Screening circular RNA related to chemotherapeutic resistance in breast cancer. Gao Danfeng,Zhang Xiufen,Liu Beibei,Meng Dong,Fang Kai,Guo Zijian,Li Lihua Epigenomics AIM:We aimed to identify circular RNAs (circRNAs) associated with breast cancer chemoresistance. MATERIALS & METHODS:CircRNA microarray expression profiles were obtained from Adriamycin (ADM) resistant MCF-7 breast cancer cells (MCF-7/ADM) and parental MCF-7 cells and were validated using quantitative real-time reverse transcription PCR. The expression data were analyzed bioinformatically. RESULTS:We detected 3093 circRNAs and identified 18 circRNAs that are differentially expressed between MCF-7/ADM and MCF-7 cells; after validating by quantitative real-time reverse transcription PCR, we predicted the possible miRNAs and potential target genes of the seven upregulated circRNAs using TargetScan and miRanda. The bioinformatics analysis revealed several target genes related to cancer-related signaling pathways. Additionally, we discovered a regulatory role of the circ_0006528-miR-7-5p-Raf1 axis in ADM-resistant breast cancer. CONCLUSION:These results revealed that circRNAs may play a role in breast cancer chemoresistance and that hsa_circ_0006528 might be a promising candidate for further functional analysis. 10.2217/epi-2017-0055
Predictive value of lncRNA LOC100505851 in breast cancer in the neoadjuvant setting. Gland surgery BACKGROUND:The expression and function of long noncoding RNA (lncRNA) LOC100505851 in breast cancer are still unknown. We aimed to examine the expression of lncRNA LOC100505851 in breast cancer and adjacent tissues and preliminarily explore its predictive value and function in breast cancer patients receiving neoadjuvant therapy (NAT). METHODS:The expression of lncRNA LOC100505851 was tested by qRT-PCR. The correlation between LOC100505851 expression and clinicopathological factors as well as pathological complete response (pCR) was analyzed by chi-squared test and logistic regression, respectively. The online database Kaplan-Meier plotter (KM plotter) was used to compare relapse-free survival (RFS) and overall survival (OS) between groups with different LOC100505851 expression levels. Subcellular localization of LOC100505851 was determined by nuclear and cytoplasmic extraction. A bioinformatics tool was used to predict RNA-binding proteins (RBPs) and interaction among these proteins. RESULTS:LncRNA LOC100505851 was significantly expressed at lower levels in cancer tissues than in adjacent tissues (P<0.001). Its expression was related to human epidermal growth factor receptor 2 (HER2) expression (P=0.003) and molecular subtype based on immunohistochemistry (P=0.001). Patients with high LOC100505851 expression were prone to pCR (OR =3.077, 95% CI: 1.042-9.086, P=0.042) and better RFS (HR =0.68, 95% CI: 0.59-0.79, P<0.001) and OS (HR =0.60, 95% CI: 0.43-0.84, P=0.0026) according to the online database KM plotter. The subcellular localization of LOC100505851 was in the nucleus, and its binding proteins were predicted by bioinformatics tools. CONCLUSIONS:LncRNA LOC100505851 was located mainly in the nucleus and was significantly downregulated in breast cancers. Its expression was related to a higher pCR rate and better RFS and OS, indicating its potential value as a novel predictive and prognostic biomarker in breast cancer. 10.21037/gs-21-3
A novel long non-coding RNA-ARA: adriamycin resistance-associated. Jiang Min,Huang Ou,Xie Zuoquan,Wu Shuchao,Zhang Xi,Shen Aijun,Liu Hongchun,Chen Xiaosong,Wu Jiayi,Lou Ying,Mao Yan,Sun Kan,Hu Shudong,Geng Meiyu,Shen Kunwei Biochemical pharmacology Long non-coding RNAs (lncRNAs) are emerging as an integral functional component of human genome and have been investigated as critical regulators in molecular biology of cancer. A recent study reported that lncRNA-UCA1 induced drug resistance in adriamycin chemotherapy. However, the contributions of lncRNAs to adriamycin resistance in cancers remain largely unknown. To address this issue, we performed a genome-wide lncRNA microarray analysis in adriamycin resistant MCF-7/ADR and parental MCF-7 cells, and revealed differential expression of lncRNAs in distinct category and chromosome distribution patterns. A specific differentially expressed lncRNA (Adriamycin Resistance Associated, termed ARA) was validated in MCF-7/ADR and HepG2/ADR cells. ARA is derived from an intron of PAK3 gene, predicted to contain several stable hairpins in secondary structure and has conservative sequences in primates. ARA expression is significantly associated with adriamycin sensitivity in a panel of breast and liver cancer cell lines and is markedly up-regulated in parental sensitive MCF-7 and HepG2 cell lines after receiving adriamycin treatment. The functions of ARA were assessed by silencing this lncRNA in vitro, and we found that ARA knockdown reduced the proliferation, induced cell death, G2/M arrest and migration defects. Furthermore, microarray transcriptomic analysis was carried out to comprehensively depict the ARA-regulated genes. We showed that ARA can modulate multiple signalling pathways, including MAPK signalling pathway, metabolism pathways, cell cycle and cell adhesion-related biological pathways, and regulate cellular processes, including transcriptional processes and protein binding function. Overall, our results indicate novel insights of adriamycin resistance in lncRNA level. 10.1016/j.bcp.2013.10.020
Transcriptome Analysis of Triple-Negative Breast Cancer Reveals an Integrated mRNA-lncRNA Signature with Predictive and Prognostic Value. Jiang Yi-Zhou,Liu Yi-Rong,Xu Xiao-En,Jin Xi,Hu Xin,Yu Ke-Da,Shao Zhi-Ming Cancer research While recognized as a generally aggressive disease, triple-negative breast cancer (TNBC) is highly diverse in different patients with variable outcomes. In this prospective observational study, we aimed to develop an RNA signature of TNBC patients to improve risk stratification and optimize the choice of adjuvant therapy. Transcriptome microarrays for 33 paired TNBC and adjacent normal breast tissue revealed tumor-specific mRNAs and long noncoding RNAs (lncRNA) that were associated with recurrence-free survival. Using the Cox regression model, we developed an integrated mRNA-lncRNA signature based on the mRNA species for FCGR1A, RSAD2, CHRDL1, and the lncRNA species for HIF1A-AS2 and AK124454 The prognostic and predictive accuracy of this signature was evaluated in a training set of 137 TNBC patients and then validated in a second independent set of 138 TNBC patients. In addition, we enrolled 82 TNBC patients who underwent taxane-based neoadjuvant chemotherapy (NCT) to further verify the predictive value of the signature. In both the training and validation sets, the integrated signature had better prognostic value than clinicopathologic parameters. We also confirmed the interaction between the administration of taxane-based NCT and different risk groups. In the NCT cohort, patients in the low-risk group were more likely to achieve pathologic complete remission after taxane-based NCT (P = 0.014). Functionally, we showed that HIF1A-AS2 and AK124454 promoted cell proliferation and invasion in TNBC cells and contributed there to paclitaxel resistance. Overall, our results established an integrated mRNA-lncRNA signature as a reliable tool to predict tumor recurrence and the benefit of taxane chemotherapy in TNBC, warranting further investigation in larger populations to help frame individualized treatments for TNBC patients. Cancer Res; 76(8); 2105-14. ©2016 AACR. 10.1158/0008-5472.CAN-15-3284
Highly penetrating nanobubble polymer enhances LINC00511-siRNA delivery for improving the chemosensitivity of triple-negative breast cancer. Yuan Yanchi,Li Erjing,Zhao Jing,Wu Bolin,Na Ziyue,Cheng Wen,Jing Hui Anti-cancer drugs Ultrasound-mediated nanobubble destruction (UMND), which can utilize the physical energy of ultrasound irradiation to improve the transfer efficiency to target cells is becoming one of the most promising carriers for gene delivery. The purpose of this study was to establish cell-penetrating peptide (CPP)-loaded nanobubbles (CNBs) connected with long intergenic nonprotein coding RNA 00511-small interfering RNA (LINC00511-siRNA) and evaluate its feasibility for improving the chemosensitivity of triple-negative breast cancer in vitro. First, fluorescence imaging confirmed the loading of siLINC00511 on CNBs, and the CNBs-siLINC00511 were characterized by the Zetasizer Nano ZS90 analyzer and transmission electron microscopy. Next, cell counting kit 8 assay was used to detect the inhibitory activity of cisplatin on the proliferation of MDA-MB-231 cells, and the 50% inhibition concentration value before and after transfer was calculated. Finally, the silencing effect of siLINC00511 was evaluated in vitro using an apoptosis assay, transwell assay, real time-PCR and western blotting. UMND combined with CNBs could effectively transfer the siRNA to MDA-MB-231 cells, thus evidently reducing the expression of LINC00511. Furthermore, inhibitory activity of cisplatin on MDA-MB-231 cells was enhanced after downregulation of LINC00511 expression. Downregulation of LINC00511 alters expression of cell cycle-related (CDK 6) and apoptosis-related (Bcl-2 and Bax) proteins in MDA-MB-231 cells. These results suggested that siRNA-CNBs may be an ideal vector for the treatment of tumors, with high efficiency RNA interference under the combined action of UMND. It may provide a new therapeutic method for triple negative breast cancer. 10.1097/CAD.0000000000000985
Hypermethylation of lncRNA MEG3 impairs chemosensitivity of breast cancer cells. Li Hongchang,Wang Puhua,Liu Jiazhe,Liu Weiyan,Wu Xubo,Ding Junbin,Kang Jie,Li Jindong,Lu Jingfeng,Pan Gaofeng Journal of clinical laboratory analysis BACKGROUND:Chemoresistance posed a barrier to successful treatment of breast cancer (BC), and lncRNA MEG3 has been documented to implicate in BC development. However, whether MEG3 methylation, which led to low MEG3 expression, was relevant to BC progression and chemoresistance remained uncertain. METHODS:In the aggregate, 374 pairs of tumor tissues and adjacent normal tissues were collected from pathologically confirmed BC patients, and four BC cell lines, including MDA-MB-231, Bcap-37, MCF-7, and SK-BR-3, were purchased. Moreover, methylation-specific polymerase chain reaction (PCR) was adopted to evaluate the methylation status of BC tissues and cell lines, and chemo-tolerance of BC cell lines was assessed by performing MTT assay. Concurrently, transwell assay and scratch assay were carried out to estimate the migratory and invasive capability of BC cell lines. RESULTS:Methylated MEG3, lowly expressed MEG3, large tumor size (≥2 cm), advanced TNM grade and lymphatic metastasis were potentially symbolic of poor prognosis among BC patients (P < .05). Besides, MDA-MB-231 cell line exhibited the strongest resistance against paclitaxel, adriamycin, and vinorelbine (P < .05), while MCF-7 cell line seemed more sensitive against these drugs than any other BC cell line (P < .05). Furthermore, pcDNA3.1-MEG3 and 5-Aza-dC markedly sensitized MDA-MB-231 and MCF-7 cell lines against the drug treatments (P < .05). Simultaneously, proliferation and metastasis of the BC cell lines were slowed down under the force of pcDNA3.1-MEG3 and 5-Aza-dC (P < .05). CONCLUSION:Preventing methylation of MEG3 might matter in lessening BC chemoresistance, owing to its hindering proliferation and metastasis of BC cells. 10.1002/jcla.23369
LncRNA AWPPH and miRNA-21 regulates cancer cell proliferation and chemosensitivity in triple-negative breast cancer by interacting with each other. Liu Ai-Na,Qu Hua-Jun,Gong Wen-Jing,Xiang Jin-Yu,Yang Miao-Miao,Zhang Wei Journal of cellular biochemistry Long-non-coding RNAs (lncRNA) AWPPH promotes the progression of liver and bladder cancer, indicating its oncogenic role. The current study aimed to explore the involvement of AWPPH in triple-negative breast cancer (TNBC). In the current study, we found that plasma levels of lncRNA AWPPH and microRNA-21 (miRNA-21) were upregulated in patients with TNBC than in healthy controls, and the upregulation of plasma lncRNA AWPPH and miRNA-21 distinguished early-stage patients with TNBC from healthy controls. Plasma levels of lncRNA AWPPH and miRNA-21 were significantly and positively correlated in both patients with TNBC and healthy controls. LncRNA AWPPH and miRNA-21 overexpression led to promoted cancer cells proliferation and improved cancer cell viability under carboplatin treatment, while lncRNA AWPPH small interfering RNA (siRNA) silencing played an opposite role. In addition, miRNA-21 overexpression attenuated the effects of lncRNA AWPPH siRNA silencing on of cancer cell behaviors. LncRNA AWPPH overexpression led to upregulated miRNA-21 in TNBC cells, while miRNA-21 overexpression also led to significantly upregulated lncRNA AWPPH expression. Therefore, lncRNA AWPPH and miRNA-21 may regulate cancer cell proliferation and chemosensitivity in TNBC by interacting with each other. 10.1002/jcb.28747
MYC-binding lncRNA EPIC1 promotes AKT-mTORC1 signaling and rapamycin resistance in breast and ovarian cancer. Wang Yifei,Zhang Min,Wang Zehua,Guo Weiwei,Yang Da Molecular carcinogenesis AKT-mTORC1 (mammalian target of rapamycin complex 1) signaling pathway plays a critical role in tumorigenesis and can be targeted by rapamycin. However, the underlying mechanism of how long noncoding RNA (lncRNAs) regulate the AKT-mTORC1 pathway remains unclear. EPIC1 (epigenetically-induced lncRNA 1) is a Myc-binding lncRNA, which has been previously demonstrated to be overexpressed in multiple cancer types. In a pathway analysis including 4962 cancer patients, we observed that lncRNA EPIC1 expression was positively correlated with the AKT-mTORC1 signaling pathway in more than 10 cancer types, including breast and ovarian cancers. RNA-seq analysis of breast and ovarian cancer cells demonstrated that EPIC1-knockdown led to the downregulation of genes in the AKT-mTORC1 signaling pathway. In MCF-7, OVCAR4, and A2780cis cell lines, EPIC1 knockdown and overexpression, respectively, inhibited and activated phosphorylated AKT and the downstream phosphorylation levels of 4EBP1 and S6K. Further knockdown of Myc abolished the EPIC1's regulation of AKT-mTORC1 signaling; suggested that the regulation of phosphorylation level of AKT, 4EBP1, and S6K by EPIC1 depended on the expression of Myc. Moreover, EPIC1 overexpressed MCF-7, A2780cis, and OVCAR4 cells treated with rapamycin showed a significant decreasing in rapamycin mediated inhibition of p-S6K and p-S6 comparing with the control group. In addition, Colony Formation assay and MTT assay indicated that EPIC1 overexpression led to rapamycin resistance in breast and ovarian cancer cell lines. Our results demonstrated the lncRNA EPIC1 expression activated the AKT-mTORC1 signaling pathway through Myc and led to rapamycin resistance in breast and ovarian cancer. 10.1002/mc.23248
lncMat2B regulated by severe hypoxia induces cisplatin resistance by increasing DNA damage repair and tumor-initiating population in breast cancer cells. García-Venzor Alfredo,Mandujano-Tinoco Edna Ayerim,Ruiz-Silvestre Araceli,Sánchez José Manuel,Lizarraga Floria,Zampedri Cecilia,Melendez-Zajgla Jorge,Maldonado Vilma Carcinogenesis Multicellular tumor spheroids (MCTSs) constitute a three-dimensional culture system that recapitulates the in vivo tumor microenvironment. Tumor cells cultured as MCTSs present antineoplastic resistance due to the effect of microenvironmental signals acting upon them. In this work, we evaluated the biological function of a new microenvironment-regulated long non-coding RNA, lncMat2B, in breast cancer. In MCTSs, the expression of lncMat2B presented an increase and a zonal heterogeneity, as it was expressed principally in quiescent cells of hypoxic regions of the MCTSs. As expected, functional assays supported the role of severe hypoxia in the regulation of lncMat2B. Moreover, gain- and loss-of-function assays using a transcriptional silencing CRISPR/Cas9 system and gBlock revealed that lncMAT2B regulates the tumor-initiating phenotype. Interestingly, lncMat2B is overexpressed in a cisplatin-resistant MCF-7 cell line, and its ectopic expression in wild type MCF-7 cells increased survival to cisplatin exposure by reducing DNA damage and reactive oxygen species accumulation. lncMAT2B is a possible link between severe hypoxia, tumor-initiating phenotype and drug resistance in breast cancer cells. 10.1093/carcin/bgaa078
LINC00160 mediated paclitaxel-And doxorubicin-resistance in breast cancer cells by regulating TFF3 via transcription factor C/EBPβ. Wu Huaiguo,Gu Juan,Zhou Daoping,Cheng Wei,Wang Yueping,Wang Qingping,Wang Xuedong Journal of cellular and molecular medicine Chemoresistance represents a major challenge in breast cancer (BC) treatment. This study aimed to probe the roles of LINC00160 in paclitaxel- and doxorubicin-resistant BC cells. Three pairs of BC and adjacent normal tissue were used for lncRNA microarray analysis. Paclitaxel-resistant MCF-7 (MCF-7/Tax) and doxorubicin-resistant BT474 (BT474/Dox) cells were generated by exposure of parental drug-sensitive MCF-7 or BT474 cells to gradient concentrations of drugs. Correlation between LINC00160 expression and clinical response to paclitaxel in BC patients was examined. Short interfering RNAs specifically targeting LINC00160 or TFF3 were designed to construct LINC00160- and TFF3-depleted BC cells to discuss their effects on biological episodes of MCF-7/Tax and BT474/Dox cells. Interactions among LINC00160, transcription factor C/EBPβ and TFF3 were identified. MCF-7/Tax and BT474/Dox cells stable silencing of LINC00160 were transplanted into nude mice. Consequently, up-regulated LINC00160 led to poor clinical response to paclitaxel in BC patients. LINC00160 knockdown reduced drug resistance in MCF-7/Tax and BT474/Dox cells and reduced cell migration and invasion. LINC00160 recruited C/EBPβ into the promoter region of TFF3 and increased TFF3 expression. LINC00160-depleted MCF-7/Tax and BT474/Dox cells showed decreased tumour growth rates in nude mice. Overall, we identified a novel mechanism of LINC00160-mediated chemoresistance via the C/EBPβ/TFF3 axis, highlighting the potential of LINC00160 for treating BC with chemoresistance. 10.1111/jcmm.15487
LncRNA DLX6-AS1 Contributes to Epithelial-Mesenchymal Transition and Cisplatin Resistance in Triple-negative Breast Cancer via Modulating Mir-199b-5p/Paxillin Axis. Du Chuang,Wang Yan,Zhang Yingying,Zhang Jianhua,Zhang Linfeng,Li Jingruo Cell transplantation Triple-negative breast cancer (TNBC) is one of the most aggressive cancer types with high recurrence, metastasis, and drug resistance. Recent studies report that long noncoding RNAs (lncRNAs)-mediated competing endogenous RNAs (ceRNA) play an important role in tumorigenesis and drug resistance of TNBC. Although elevated lncRNA DLX6 antisense RNA 1 (DLX6-AS1) has been observed to promote carcinogenesis in various cancers, the role in TNBC remained unclear. In this study, expression levels of DLX6-AS1 were increased in TNBC tissues and cell lines when compared with normal tissues or breast fibroblast cells which were determined by quantitative real-time PCR (RT-qPCR). Then, CCK-8 assay, cell colony formation assay and western blot were performed in CAL-51 cells transfected with siRNAs of DLX6-AS1 or MDA-MB-231 cells transfected with DLX6-AS1 over expression plasmids. Knock down of DLX6-AS1 inhibited cell proliferation, epithelial-mesenchymal transition (EMT), decreased expression levels of BCL2 apoptosis regulator (Bcl-2), Snail family transcriptional repressor 1 (Snail) as well as N-cadherin and decreased expression levels of cleaved caspase-3, γ-catenin as well as E-cadherin, while up regulation of DLX6-AS1 had the opposite effect. Besides, knockdown of DLX6-AS1 in CAL-51 cells or up regulation of DLX6-AS1 in MDA-MB-231 cells also decreased or increased cisplatin resistance of those cells analyzed by MTT assay. Moreover, by using dual luciferase reporter assay, RNA immunoprecipitation and RNA pull down assay, a ceRNA which was consisted by lncRNA DLX6-AS1, microRNA-199b-5p (miR-199b-5p) and paxillin (PXN) was identified. And DLX6-AS1 function through miR-199b-5p/PXN in TNBC cells. Finally, results of xenograft experiments using nude mice showed that DLX6-AS1 regulated cell proliferation, EMT and cisplatin resistance by miR-199b-5p/PXN axis in vivo. In brief, DLX6-AS1 promoted cell proliferation, EMT, and cisplatin resistance through miR-199b-5p/PXN signaling in TNBC in vitro and in vivo. 10.1177/0963689720929983
Silencing of lncRNA PART1 inhibits proliferation, invasion and migration of breast cancer cells and promotes the efficacy of cisplatin in breast cancer cells. Zhang Li,Zhang Jie,Ni Chuandou General physiology and biophysics LncRNAs have proved to be related to the progression of multiple cancers. The present study aimed to investigate the effect of PART1 on the proliferation, invasion and migration of breast cancer cells and the efficacy of cisplatin in these cells. The expression of lncRNA PART1 in tissues and cells were detected by RT-qPCR analysis which was also used to verify the transfection effects. The cell proliferation, invasion and migration of breast cancer cells were respectively analyzed by CCK-8 assay, transwell assay and wound healing assay. The cell apoptosis was determined by flow cytometry analysis. The detection of CDK2, cyclinE1, P21, MMP3, MMP10, MMP13, Bcl2, Bax, cleaved caspase-3, caspase-3, MDP1, MRP1, GST-π and ABCB1 expression was performed by Western blot analysis. The results revealed that PART1 was increased in breast cancer tissues and cells, silencing of PART1 significantly inhibited cell proliferation, invasion and migration by regulating the expression of relative proteins. In addition, silencing of PART1 obviously improved the sensitivity of breast cancer cells to cisplatin, promoted cell apoptosis, and decreased the expression of breast cancer resistance proteins. In conclusion, silencing of PART1 inhibited proliferation, invasion and migration of breast cancer cells and promoted the efficacy of cisplatin in these cells. Therefore, PART1 may be considered as a novel therapeutic target in breast cancer. 10.4149/gpb_2020008
Knockdown of lncRNA H19 restores chemo-sensitivity in paclitaxel-resistant triple-negative breast cancer through triggering apoptosis and regulating Akt signaling pathway. Han Jiguang,Han Baojuan,Wu Xueya,Hao Jie,Dong Xiaoqun,Shen Qiang,Pang Hui Toxicology and applied pharmacology Triple negative breast cancer (TNBC) is associated with poor prognosis and systemic chemotherapy is the only treatment for TNBC. However, development of chemo-resistance remains a major obstacle for TNBC treatment. Paclitaxel-resistance is mainly related to the activation of the Akt signaling pathway and deregulation of apoptotic regulatory proteins. LncRNAs are frequently dysregulated in various malignancies, including breast cancer, facilitating cell proliferation, metastasis and drug resistance. LncRNA H19 is overexpressed in approximately 70% of breast cancer patients, and has been reported to confer chemo-resistance in breast cancer. In the present study, we investigated the expression level of lncRNA H19 in paclitaxel-resistant and paclitaxel-sensitive cell lines. The results showed that the level of lncRNA H19 expression in paclitaxel-resistant cells was significantly higher than that in paclitaxel-sensitive cells, and knockdown of lncRNA H19 might restore chemo-sensitivity in paclitaxel-resistant TNBC by mediating the AKT signaling pathway. Thus, lncRNA H19 might be an efficient therapeutic target in paclitaxel-resistant TNBC treatment. 10.1016/j.taap.2018.09.018
lncRNA profile study reveals the mRNAs and lncRNAs associated with docetaxel resistance in breast cancer cells. Huang Peide,Li Fengyu,Li Lin,You Yuling,Luo Shizhi,Dong Zhensheng,Gao Qiang,Wu Song,Brünner Nils,Stenvang Jan Scientific reports Resistance to adjuvant systemic treatment, including taxanes (docetaxel and paclitaxel) is a major clinical problem for breast cancer patients. lncRNAs (long non-coding RNAs) are non-coding transcripts, which have recently emerged as important players in a variety of biological processes, including cancer development and chemotherapy resistance. However, the contribution of lncRNAs to docetaxel resistance in breast cancer and the relationship between lncRNAs and taxane-resistance genes are still unclear. Here, we performed comprehensive RNA sequencing and analyses on two docetaxel-resistant breast cancer cell lines (MCF7-RES and MDA-RES) and their docetaxel-sensitive parental cell lines. We identified protein coding genes and pathways that may contribute to docetaxel resistance. More importantly, we identified lncRNAs that were consistently up-regulated or down-regulated in both the MCF7-RES and MDA-RES cells. The co-expression network and location analyses pinpointed four overexpressed lncRNAs located within or near the ABCB1 (ATP-binding cassette subfamily B member 1) locus, which might up-regulate the expression of ABCB1. We also identified the lncRNA EPB41L4A-AS2 (EPB41L4A Antisense RNA 2) as a potential biomarker for docetaxel sensitivity. These findings have improved our understanding of the mechanisms underlying docetaxel resistance in breast cancer and have provided potential biomarkers to predict the response to docetaxel in breast cancer patients. 10.1038/s41598-018-36231-4
LncRNA XIST promotes chemoresistance of breast cancer cells to doxorubicin by sponging miR-200c-3p to upregulate ANLN. Zhang Min,Wang Feng,Xiang Zhen,Huang Teng,Zhou Wei-Bing Clinical and experimental pharmacology & physiology The resistance of breast cancer cells to drugs is a major obstacle to effective cancer chemotherapy. Here, we study the function mechanisms of long non-coding RNA XIST in chemoresistance of breast cancer to doxorubicin. We examined the 50% inhibitive concentration of doxorubicin to MDA-MB-231 and MDA-MB-231/ADM cells, showing that the doxorubicin resistance of MDA-MB-231/ADM cells was much higher than MDA-MB-231 cells. The gene or protein expression of XIST and ANLN were also higher in MDA-MB-231/ADM cells than that in MDA-MB-231 cells. Moreover, XIST overexpression promoted cell proliferation and inhibited apoptosis of doxorubicin-treated MDA-MB-231 cells by promoting ANLN expression. XIST silencing inhibited cell proliferation and promoted apoptosis of doxorubicin-treated MDA-MB-231/ADM cells by inhibiting ANLN expression. Luciferase reporter assay showed that XIST functioned as a competing endogenous RNA to repress miR-200c-3p, which controlled its downstream target ANLN. In conclusion, these data reveal that XIST promotes chemoresistance of breast cancer cells to doxorubicin by sponging miR-200c-3p to upregulate ANLN. This work explores the relationship between lncRNA XIST and doxorubicin resistance in breast cancer cells and highlights a novel therapeutic target for the treatment of breast cancer. 10.1111/1440-1681.13307
Long non-coding RNA H19 regulates proliferation and doxorubicin resistance in MCF-7 cells by targeting PARP1. Wang Yu,Zhou Peihong,Li Ping,Yang Fengxia,Gao Xue-Qiang Bioengineered Chemoresistance is a major obstacle to effective breast cancer chemotherapy. However, the underlying molecular mechanisms remain unclear. The long noncoding RNA H19 (H19) is involved in various stages of tumorigenesis, however, its role in doxorubicin resistance remains unknown. The goal of this study was to evaluate the role of H19 in the development of doxorubicin-resistant breast cancer. Quantitative real-time PCR (qRT-PCR) analyzed H19 expression in chemotherapy-resistant and sensitive breast cancer tissues. Both knockdown and overexpression of H19 were used to assess the sensitivity to doxorubicin in breast cancer cells . qRT-PCR and Western blot were used to explore the doxorubicin resistance mechanism of H19. We observed that the H19 expression was significantly upregulated in chemotherapy-resistant breast cancer tissues and doxorubicin-resistant breast cancer cell lines. Knockdown of H19 enhanced the sensitivity to doxorubicin both and . While H19 overexpression developed doxorubicin-resistant in breast cancer cells both and . Furthermore, it was revealed that H19 negatively regulated PARP1 expression in breast cancer cells following doxorubicin treatment. Knockdown of H19 sensitized breast cancer cells to doxorubicin by promoting PARP1 upregulation. H19 overexpression could recapitulate doxorubicin resistance by PARP1 downregulation. Our findings revealed that H19 plays a leading role in breast cancer chemoresistance development, mediated mainly through a H19-PARP1 pathway. 10.1080/21655979.2020.1761512
Structure of LINC00511-siRNA-conjugated nanobubbles and improvement of cisplatin sensitivity on triple negative breast cancer. Wu Bolin,Yuan Yanchi,Han Xue,Wang Qiucheng,Shang Haitao,Liang Xitian,Jing Hui,Cheng Wen FASEB journal : official publication of the Federation of American Societies for Experimental Biology The drug resistance of triple negative breast cancer (TNBC) is considered as a major obstacle for the curative effect of chemotherapy. Long intergenic noncoding RNA 00511 (LINC00511) has been considered as a target gene of drug resistance. A novel theranostic agent loaded with LINC00511-siRNA to deliver siRNA was structured, and the responses of drug sensitivity in TNBC were detected. Next-generation high-throughput RNA sequencing (RNA-Seq) was performed to accurately analyze the differential expression of mRNAs and lncRNA targets after LINC00511-siRNA transfection with low-frequency ultrasound (LFUS). The LINC00511-siRNA conjugated nanobubble complexes showed appropriate characterization, with a mean diameter of 516.1 ± 24.7 nm and a zeta potential of -38.05 ± 0.24 mV. The transfection efficiency of nanobubble complexes was approximately 50% with LFUS. By RNA-Seq, the differential expressions of lncRNA transcripts and mRNA transcripts were identified, and then analyzed. The GO and KEGG enrichment analyses revealed the TNBC drug resistance related target genes and pathways. The combination of LFUS irradiation and nanobubble complexes is regarded as an efficient and safe method for siRNA transfection. The TNBC drug resistance occurs as a result of synergistic reactions between a variety of genes and a variety of pathways. 10.1096/fj.202000481R
LINC00511 knockdown enhances paclitaxel cytotoxicity in breast cancer via regulating miR-29c/CDK6 axis. Zhang Hualong,Zhao Bin,Wang Xiuxia,Zhang Fan,Yu Wenlong Life sciences AIMS:Drug resistance is becoming a major clinical challenge to the success of breast cancer treatment. Compelling evidence has shown the association between the deregulated long non-coding RNAs (lncRNAs) and drug resistance in various malignancies. However, the effects of long intergenic noncoding RNA 00511 (LINC00511), a newly identified oncogenic lncRNA, on the drug resistance of breast cancer cells remain unknown. MAIN METHODS:RT-qPCR was performed to detect the expressions of LINC00511, miR-29c, and cyclin dependent kinase 6 (CDK6) in breast cancer tissues and cells. Pearson correlation analysis was used to analyze the correlation between miR-29c, CDK6 and LINC00511 expression in breast cancer tissues. The interactions between LINC00511, CDK6 and miR-29c were explored by luciferase reporter assay, RT-qPCR and western blot. MTT assay and flow cytometry analysis were applied to evaluate paclitaxel cytotoxicity. KEY FINDINGS:LINC00511 and CDK6 were upregulated while miR-29c was downregulated in breast cancer tissues and cells. miR-29c was negatively correlated with LINC00511 and CDK6 expression while LINC00511 was positively correlated with CDK6 expression in breast cancer tissues. LINC0051 directly interacted with miR-29c to suppress its expression. LINC00511 knockdown enhanced paclitaxel cytotoxicity in breast cancer cells by upregulating miR-29c. CDK6 was identified as a target of miR-29c. CDK6 knockdown attenuated the effects of miR-29c inhibition on paclitaxel cytotoxicity in breast cancer cells. LINC00511 positively regulated CDK6 expression in breast cancer cells. SIGNIFICANCE:LINC00511 knockdown enhanced paclitaxel cytotoxicity in breast cancer cells via regulating miR-29c/CDK6 axis. 10.1016/j.lfs.2019.04.063
Long noncoding RNA RP11-70C1.3 confers chemoresistance of breast cancer cells through miR-6736-3p/NRP-1 axis. Bosnian journal of basic medical sciences Chemoresistance remains a major obstacle for improving the clinical outcome of patients with breast cancer. Recently, long noncoding RNAs (lncRNAs) have been implicated in breast cancer chemoresistance. However, the function and underlying mechanism are still largely unknown. Using lncRNA microarray, we identified 122 upregulated and 475 downregulated lncRNAs that might be related to the breast cancer chemoresistance. Among them, RP11-70C1.3 was one of the most highly expressed lncRNAs. In breast cancer patients, high RP11-70C1.3 expression predicted poor prognosis. Knockdown of RP11-70C1.3 inhibited the multidrug resistance of breast cancer cells in vitro and in vivo. Further investigations revealed that RP11-70C1.3 functioned as a competing endogenous RNA (ceRNA) for miR-6736-3p to increase NRP-1 expression. Notably, the rescue experiments showed that both miR-6736-3p inhibitor and NRP-1 overexpression could partly reverse the suppressive influence of RP11-70C1.3 knockdown on breast cancer chemoresistance. In conclusion, our study indicated that lncRNA RP11-70C1.3 regulated NRP-1 expression by sponging miR-6736-3p to confer chemoresistance of breast cancer cells. RP11-70C1.3 might be a potential therapeutic target in enhancing the clinical efficacy of chemotherapy in breast cancer. 10.17305/bjbms.2021.5803
Long non-coding RNA NEAT1 confers oncogenic role in triple-negative breast cancer through modulating chemoresistance and cancer stemness. Shin Vivian Yvonne,Chen Jiawei,Cheuk Isabella Wai-Yin,Siu Man-Ting,Ho Chi-Wang,Wang Xian,Jin Hongchuan,Kwong Ava Cell death & disease Triple-negative breast cancer (TNBC) is a malignant subtype of breast cancer with the absence of targeted therapy, resulting in poor prognosis in patients. Chemotherapy remains the mainstay of treatment for TNBC; however, development of drug resistance is the main obstacle for successful treatments. In recent years, long non-coding RNA (lncRNA) has been implicated in multiple biological functions in various diseases, particularly cancers. Accumulating evidence suggested that lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) expression is dysregulated in many human cancers and thus is a useful prognostic marker for cancer patients. Nevertheless, the mechanism of how NEAT1 confers drug resistance in TNBC is still largely unknown. We performed lncRNA profiling by the LncRNA Profiler qPCR Array Kit in normal control (NC) and breast cancers (BC) blood samples and further validated in a larger cohort of samples by qRT-PCR. Gene expression level and localization were investigated by qRT-PCR, western blotting, and immunofluorescence staining. Flow cytometric analysis was carried out to detect cancer stem cells. Functional studies were performed both in vitro and in vivo xenograft model. Among 90 lncRNAs, NEAT1 was highly expressed in the blood samples of breast cancer patients than in NC. In particular, the expression of NEAT1 was higher in TNBC tissues than other subgroups. Functional studies revealed that NEAT1 conferred oncogenic role by regulating apoptosis and cell cycle progression in TNBC cells. We identified that knockdown of NEAT1 sensitized cells to chemotherapy, indicating the involvement in chemoresistance. Importantly, shNEAT1 reduced stem cell populations such as CD44+/CD24-, ALDH+, and SOX2+, implicating that NEAT1 was closely related to cancer stemness in TNBC. Our data highlighted the roles of NEAT1 chemoresistance and cancer stemness, suggesting that it could be used as a new clinical therapeutic target for treating TNBC patients especially those with drug resistance. 10.1038/s41419-019-1513-5
Long non-coding RNA TUG1 sponges miR-197 to enhance cisplatin sensitivity in triple negative breast cancer. Tang Tielei,Cheng Yonggang,She Qing,Jiang Yaru,Chen Yuanyuan,Yang Wenqiang,Li Youhuai Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie Breast cancer is the leading cause of women death worldwide. Several long non-coding RNAs (lncRNAs) have been identified as oncogenes or tumor suppressors during the progression of cancers. However, the role of taurine upregulated gene (TUG1) in mediating the chemotherapy sensitivity of triple negative breast cancer (TNBC) has not been studied yet. In TNBC patients, we observed a significant decrease of TUG1 in tumor tissues compared to the normal tissues. Similarly, TUG1 expression was significantly decreased in TNBC cell lines compared with normal breast epithelial cell line and cell lines of other subtypes of breast cancer. In MDA-MB-231 and BT549, cisplatin induced cell growth arrest was remarkably augmented by overexpression of TUG1 and was significantly reduced by TUG1 silencing. Moreover, very low concentration of cisplatin caused cell proliferation inhibition in TUG1-overexpressed-TNBC cells. In addition, we found that TUG1 negatively regulated miR-197 expression in the tested TNBC cell lines. Sponging of TUG1 to miR-197 was proved by a dual luciferase reporter assay. We further predicted and validated that nemo-like kinase (NLK), which was positively controlled by TUG1, was a target gene of miR-197. Via regulation of miR-197/NLK, TUG1 inactivated WNT signaling pathway and thus increasing chemotherapy sensitivity of TNBC cells. Analysis of TCGA database showed that higher expression of TUG1 was associated with better prognosis in breast cancer patients. Our current study drew a preliminary conclusion that TUG1 was involved in chemotherapy sensitivity in TNBC cells. 10.1016/j.biopha.2018.07.076
Long noncoding RNA H19 acts as a miR-340-3p sponge to promote epithelial-mesenchymal transition by regulating YWHAZ expression in paclitaxel-resistant breast cancer cells. Yan Lei,Yang Shuo,Yue Cheng-Xu,Wei Xin-Yu,Peng Wei,Dong Zheng-Yuan,Xu He-Nan,Chen Su-Lian,Wang Wen-Rui,Chen Chang-Jie,Yang Qing-Ling Environmental toxicology Breast cancer (BC) is the leading cause of cancer-related death in women worldwide and one of the most prevalent malignancy. In recent years, increasing evidence had illuminated that long noncoding RNAs (lncRNAs) serve as critical factors in multiple tumor progression, including BC. Emerging references had indicated that the lncRNA H19 acts as significant roles in tumor progression and epithelial-mesenchymal transition (EMT). However, the underlying molecular mechanisms and biological roles of H19 in BC invasion, metastasis and EMT are still unclear. In this study, it was detected that the expression level of H19 was increased in BC paclitaxel-resistant (PR) cells subline (MCF-7/PR) in comparison with MCF-7 parental cells. In vitro, there were demonstrated that H19 overexpression promoted BC cells proliferation, metastasis, invasion and EMT procedures, and suppressed cells apoptosis. Whereas, H19 suppression resulted in the contrary biological effects. Besides, bioinformatics tools and dual-luciferase reporters assays indicated that miR-340-3p could act as a potential target gene of H19, the underlying mechanism studies proved that H19 could act as a competing endogenous RNA (ceRNA) via competitively binding miR-340-3p to promote BC cell proliferation, metastasis and EMT by regulating tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) and potentiate the Wnt/β-catenin signaling in BC cells. In summary, our findings demonstrated that H19 could act as a ceRNA in BC progression, metastasis and EMT through modulating miR-340-3p/YWHAZ axis and activating the canonical Wnt/β-catenin signaling pathway, indicating that H19 might act as an underlying therapeutic target and prognostic biomarker for BC therapy. 10.1002/tox.22938
LncRNA SNORD3A specifically sensitizes breast cancer cells to 5-FU by sponging miR-185-5p to enhance UMPS expression. Luo Liyun,Zhang Jianlei,Tang Hailin,Zhai Dongfeng,Huang Danqing,Ling Li,Wang Xiaorong,Liu Ting,Zhang Qiong,Zhang Zhijie,He Zhimin,Zheng Guopei Cell death & disease Breast cancer is the most common cancer type in women. Long non-coding RNAs (lncRNAs) have been reported as potential new diagnostic markers, prognostic factors, and therapeutic targets in cancer. However, the specific roles and mechanisms of lncRNAs in breast cancer remain to be elucidated. Here we demonstrated the downregulation of lncRNA SNORD3A in breast cancer cells and tissues and verified its non-protein-coding property. SNORD3A overexpression had no effect on cell proliferation but specifically sensitized breast cancer cells to 5-fluorouracil (5-FU) in vitro and in vivo. Mechanistically, SNORD3A exerts its effect via enhancing uridine monophosphate synthetase (UMPS) protein expression. SNORD3A acts as a competing endogenous RNA for miR-185-5p, leading to UMPS protein upregulation. miR-185-5p overexpression disrupted the effect of SNORD3A on chemosensitization to 5-FU in vitro and in vivo. Moreover, Meis1 overexpression transcriptionally promotes SNORD3A expression, and Meis1 is downregulated in breast cancer cells and tissues. In breast cancer tissues, SNORD3A level positively correlates with Meis1 and UMPS protein levels, whereas miR-185-5p level negatively correlates with UMPS protein level. High SNORD3A transcript and Meis1 and UMPS protein levels predicts a better outcome, but high miR-185-5p level predicts a worse outcome in breast cancer patients receiving 5-FU-based chemotherapy. Our findings indicate that Meis1-regulated SNORD3A specifically sensitizes breast cancer cells to 5-FU via enhancing UMPS expression. The SNORD3A-UMPS axis may serve as a potential biomarker and therapeutic target to improve the efficacy of 5-FU-based chemotherapy for breast cancer patients. 10.1038/s41419-020-2557-2
High XIST and Low 53BP1 Expression Predict Poor Outcome after High-Dose Alkylating Chemotherapy in Patients with a BRCA1-like Breast Cancer. Schouten Philip C,Vollebergh Marieke A,Opdam Mark,Jonkers Martijn,Loden Martin,Wesseling Jelle,Hauptmann Michael,Linn Sabine C Molecular cancer therapeutics In previous studies, high expression of XIST and low expression of 53BP1 were respectively associated with poor systemic therapy outcome in patients and therapy resistance in BRCA1-deficient mouse tumor models, but have not been evaluated in BRCA1-deficient patients. Previously, we demonstrated that classifying breast cancer copy number profiles as BRCA1-like or non-BRCA1-like identified patients enriched for defects in BRCA1 that benefit from high-dose (HD) alkylating chemotherapy compared with a conventional standard regimen. We investigated whether XIST and 53BP1 expression predicted poor outcome of HD chemotherapy within 28 BRCA1-like patients from a trial randomizing between HD [4 cycles 5-fluorouracil, epirubicin, cyclophosphamide (FEC) followed by 1 cycle HD carboplatin, thiotepa, cyclophosphamide] or conventional chemotherapy (5 cycles FEC), for which both XIST and 53BP1 statuses were available. High RNA expression of XIST (n = 5) and low protein expression of 53BP1 (n = 3) expression did not coincide. Patients with either one had poor outcome after treatment with HD chemotherapy, whereas patients with low expression of XIST and high expression of 53BP1 derived substantial benefit of this regimen on recurrence-free survival, disease-free survival, and overall survival, corroborating preclinical findings. XIST and 53BP1 may be predictive biomarkers in BRCA1-like breast cancer. 10.1158/1535-7163.MCT-15-0470
Long non-coding RNA LINC-PINT attenuates paclitaxel resistance in triple-negative breast cancer cells via targeting the RNA-binding protein NONO. Chen Jinghua,Zhu Meiqin,Zou Liqiu,Xia Junxian,Huang Jiacheng,Deng Quantong,Xu Ruilian Acta biochimica et biophysica Sinica The treatment of triple-negative breast cancer (TNBC) relies largely on chemotherapies. However, it is frequent that TNBC patients develop resistance to the chemotherapy drugs. Generation of drug-resistant cell lines facilitates the identification of drug resistance. Here, we established two paclitaxel (PTX)-resistant TNBC cancer cell lines using an intermittent and stepwise method and found that long non-coding RNA long intergenic non-protein-coding RNA p53-induced transcript (LINC-PINT) was significantly decreased in PTX-resistant cancer cells. Ectopic expression of LINC-PINT sensitized both PTX-resistant TNBC and wild-type TNBC to PTX. Moreover, RNA immunoprecipitation showed that LINC-PINT bound to RNA-binding protein NONO. Overexpression of LINC-PINT resulted in the degradation of NONO in a proteasome-dependent manner and vice versa. Knockdown of NONO with siRNA sensitized TNBC to PTX. We further analyzed the expression level of LINC-PINT and NONO in patient samples via online database and found that LINC-PINT and NONO may function antagonistically in all types of breast cancers. Taken together, our data illustrated a tumor suppressor role of LINC-PINT in sensitizing TNBC to chemotherapies via destabilizing NONO. 10.1093/abbs/gmaa072
Linc-ROR promotes the progression of breast cancer and decreases the sensitivity to rapamycin through miR-194-3p targeting MECP2. Zhou Qian,Guo Juan,Huang Wenjie,Yu Xiaosi,Xu Chen,Long Xinghua Molecular oncology linc-ROR is reported to be a potential biomarker of breast cancer, but the detailed mechanism of linc-ROR-mediated breast cancer regulation has not been fully studied. We aimed to explore how linc-ROR affects proliferation, metastasis, and drug sensitivity in breast cancer. Cell lines in which linc-ROR was overexpressed or knocked down were constructed, and the cell proliferation, colony formation, cell migration, and invasion abilities of these lines were explored. A CCK-8 assay was performed to determine the sensitivity of the breast cancer cells to rapamycin. Next-generation sequencing was conducted to explore the detailed regulatory mechanism of linc-ROR; differentially expressed RNAs in the linc-ROR-overexpressing cell line compared with the negative control were screened out, and their target genes were chosen to perform Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes analysis, protein-protein interaction network analysis, and competing endogenous RNA (ceRNA) network analysis. The ceRNA mechanism of linc-ROR for miR-194-3p, which targets MECP2, was determined through dual-luciferase reporter assay, RT-qPCR, western blot, and rescue experiments. Finally, we found that linc-ROR was upregulated in breast tumor tissues. linc-ROR promoted the cell proliferation, colony formation, cell migration, and invasion of breast cancer and decreased the sensitivity of breast cancer cells to rapamycin. The overexpression of linc-ROR triggered changes in the whole transcriptome of breast cancer cells, and a total of 85 lncRNAs, 414 microRNAs, 490 mRNAs, and 92 circRNAs were differentially expressed in the linc-ROR-overexpressing cell line compared with the negative control. Through a series of bioinformatic analyses, the 'linc-ROR/miR-194-3p/MECP2' ceRNA regulatory axis was confirmed to be involved in the linc-ROR-mediated progression and drug sensitivity of breast cancer. In conclusion, linc-ROR serves as an onco-lncRNA in breast cancer and promotes the survival of breast cancer cells during rapamycin treatment by functioning as a ceRNA sponge for miR-194-3p, which targets MECP2. 10.1002/1878-0261.12700
Transcriptome Analysis Identifies GATA3-AS1 as a Long Noncoding RNA Associated with Resistance to Neoadjuvant Chemotherapy in Locally Advanced Breast Cancer Patients. Contreras-Espinosa Laura,Alcaraz Nicolás,De La Rosa-Velázquez Inti A,Díaz-Chávez José,Cabrera-Galeana Paula,Rebollar-Vega Rosa,Reynoso-Noverón Nancy,Maldonado-Martínez Héctor A,González-Barrios Rodrigo,Montiel-Manríquez Rogelio,Bautista-Sánchez Diana,Castro-Hernández Clementina,Alvarez-Gomez Rosa M,Jiménez-Trejo Francisco,Tapia-Rodríguez Miguel,García-Gordillo José A,Pérez-Rosas Augusto,Bargallo-Rocha Enrique,Arriaga-Canon Cristian,Herrera Luis A The Journal of molecular diagnostics : JMD Breast cancer is one of the leading causes of mortality in women worldwide, and neoadjuvant chemotherapy has emerged as an option for the management of locally advanced breast cancer. Extensive efforts have been made to identify new molecular markers to predict the response to neoadjuvant chemotherapy. Transcripts that do not encode proteins, termed long noncoding RNAs (lncRNAs), have been shown to display abnormal expression profiles in different types of cancer, but their role as biomarkers in response to neoadjuvant chemotherapy has not been extensively studied. Herein, lncRNA expression was profiled using RNA sequencing in biopsies from patients who subsequently showed either response or no response to treatment. GATA3-AS1 was overexpressed in the nonresponder group and was the most stable feature when performing selection in multiple random forest models. GATA3-AS1 was experimentally validated by quantitative RT-PCR in an extended group of 68 patients. Expression analysis confirmed that GATA3-AS1 is overexpressed primarily in patients who were nonresponsive to neoadjuvant chemotherapy, with a sensitivity of 92.9% and a specificity of 75.0%. The statistical model was based on luminal B-like patients and adjusted by menopausal status and phenotype (odds ratio, 37.49; 95% CI, 6.74-208.42; P = 0.001); GATA3-AS1 was established as an independent predictor of response. Thus, lncRNA GATA3-AS1 is proposed as a potential predictive biomarker of nonresponse to neoadjuvant chemotherapy. 10.1016/j.jmoldx.2021.07.014
Long non-coding RNA FTH1P3 activates paclitaxel resistance in breast cancer through miR-206/ABCB1. Wang Ruoming,Zhang Tengteng,Yang Zhen,Jiang Chunxia,Seng Jingjing Journal of cellular and molecular medicine Emerging evidence has indicated the important function of long non-coding RNAs (lncRNAs) in tumour chemotherapy resistance. However, the underlying mechanism is still ambiguous. In this study, we investigate the physiopathologic role of lncRNA ferritin heavy chain 1 pseudogene 3 (FTH1P3) on the paclitaxel (PTX) resistance in breast cancer. Results showed that lncRNA FTH1P3 was up-regulated in paclitaxel-resistant breast cancer tissue and cells (MCF-7/PTX and MDA-MB-231/PTX cells) compared with paclitaxel-sensitive tissue and parental cell lines (MCF-7, MDA-MB-231). Gain- and loss-of-function experiments revealed that FTH1P3 silencing decreased the 50% inhibitory concentration (IC50) value of paclitaxel and induced cell cycle arrest at G2/M phase, while FTH1P3-enhanced expression exerted the opposite effects. In vivo, xenograft mice assay showed that FTH1P3 silencing suppressed the tumour growth of paclitaxel-resistant breast cancer cells and ABCB1 protein expression. Bioinformatics tools and luciferase reporter assay validated that FTH1P3 promoted ABCB1 protein expression through targeting miR-206, acting as a miRNA "sponge." In summary, our results reveal the potential regulatory mechanism of FTH1P3 on breast cancer paclitaxel resistance through miR-206/ABCB1, providing a novel insight for the breast cancer chemoresistance. 10.1111/jcmm.13679
Circulating HOTAIR expression predicts the clinical response to neoadjuvant chemotherapy in patients with breast cancer. Lu Rongzhao,Zhang Jie,Zhang Wei,Huang Yanhua,Wang Ningxia,Zhang Qing,Qu Shaohua Cancer biomarkers : section A of Disease markers BACKGROUND:Long noncoding RNA HOTAIR has been detected in the serum of patients with various malignances and may be served as novel biomarker for diagnosis and prognosis prediction of breast cancer. However, the value of circulating HOTAIR to predict the response to neoadjuvant chemotherapy (NAC) remains unclear. OBJECTIVE:In the present study, we analyzed whether pretreatment circulating HOTAIR levels predict the response to NAC and investigated prognostic impact of circulating HOTAIR on disease-free survival (DFS) in breast cancer patients treated with NAC. METHODS:Circulating HOTAIR levels in the serum of 112 breast cancer patients before NAC were measured using quantitative real-time PCR. The correlation of circulating HOTAIR with the clinicopathologic status and the response to NAC were analyzed. Kaplan-Meier survival analysis and log-rank test were used to estimate the DFS. RESULTS:In 112 serum samples obtained before NAC, high circulating HOTAIR was associated with larger tumor size, more positive lymph nodes as well as more distant metastasis. However, there was no significant correlation between the circulating HOTAIR levels and age, Ki67 status or hormone receptor. Furthermore, patients with high circulating HOTAIR achieved less clinical response as well as pathologic complete response than those with low circulating HOTAIR (p< 0.05). The Kaplan-Meier survival curve with a median follow-up of 48 months demonstrated that patients with high circulating HOTAIR expression had a worse disease-free survival than those with low circulating HOTAIR (log-rank p= 0.012). CONCLUSIONS:High circulating HOTAIR level correlates with less response to neoadjuvant chemotherapy as well as a worse prognosis in breast cancer patients. Therefore, the present study provides a favorable basis to use circulating HOTAIR as a predictor of neoadjuvant chemotherapy response. 10.3233/CBM-170874
Long non-coding RNA CRALA is associated with poor response to chemotherapy in primary breast cancer. Li Yudong,Wang Baoxiao,Lai Hongna,Li Shunying,You Qiuting,Fang Yichao,Li Qian,Liu Yujie Thoracic cancer BACKGROUND:Breast cancer is the most commonly diagnosed cancer in women, and has become the second leading cause of cancer death among women worldwide. Chemoresistance has become an important problem in breast cancer clinics. The identification of new mechanisms affecting chemosensitivity is of great clinical value for the treatment of breast cancer. METHODS:The expression levels of chemoresistance-associated long non-coding RNA (CRALA), a newly discovered long non-coding RNA, were measured by quantitative real time-PCR in 79 pre-treatment biopsied primary breast cancer samples. Small interfering RNAs were used to knockdown CRALA expression. The effect of CRALA on chemosensitivity was evaluated using cell growth assay. RESULTS:Non-responding tumors (poor response to chemotherapy, 32 samples) had fourfold higher CRALA expression than responding tumors (good response to chemotherapy, 47 samples). CRALA is upregulated in chemoresistant breast cancer cell lines compared to their parental lines. Silencing of CRALA in chemoresistant breast cancer cells resensitizes the cells to chemotherapy in vitro. Furthermore, univariate and multivariate analysis showed that higher CRALA expression was significantly associated with poor prognosis in 144 breast cancer patients. CONCLUSION:The study findings indicate that CRALA expression may be an important biomarker for predicting the clinical response to chemotherapy and prognosis in breast cancer patients. It is possible to target CRALA to reverse chemoresistance in breast cancer patients. 10.1111/1759-7714.12487
A nine-lncRNA signature predicts distant relapse-free survival of HER2-negative breast cancer patients receiving taxane and anthracycline-based neoadjuvant chemotherapy. Sun Min,Liu Xiaoxiao,Xia Lingyun,Chen Yuying,Kuang Li,Gu Xinsheng,Li Tian Biochemical pharmacology Multi-gene prognostic signatures of long non-coding RNAs (lncRNAs) provide new insights into mechanisms of HER2-negative breast cancer development and progression, and predict distant relapse-free survival (DRFS) of patients receiving taxane and anthracycline-based neoadjuvant chemotherapy. The aim of this study was to develop such a multi-lncRNAs signature. Optimal multiple candidate signature lncRNAs associated with DRFS were firstly identified by a univariate Cox proportional hazard regression survival analysis and a robust likelihood-based survival analysis of the GEO dataset GSE25055. A nine-lncRNA prognostic risk score model Risk Score = 0.0289 × EXP - 0.0814 × EXP - 0.2422 × EXP - 0.2433 × EXP + 0.4690 × EXP - 0.2483 × EXP - 0.2464 × EXP + 0.3349 × EXP - 0.0216 × EXP was built according to the coefficients of multivariate survival analysis of the association between the candidate lncRNAs and survival. EXP was the standardized log2-transformed expression level of the gene. According to this model, higher scores predicted lower survival probability. The area under Receiver operating characteristic (ROC) curve (AUC) was 0.777 to 0.823 from 1- to 7- year survival rate. The model and its individual lncRNAs differentiated survival probability between the higher scores (expression) and the lower scores (expression). The nine-lncRNA signature had the robust prognostic power compared with ER, PR, tumor size (T), lymph node invasion (N), TNM stage, pathologic response, chemosensitivity prediction and PAM50 signature. These results were consistent with those based on the GEO dataset GSE25065. The predictive nomograms integrating both the nine-lncRNA signature classifier and clinical-pathological risk factors were robust in predicting 1-, 3- and 5- year survival probabilities. These results supported that the nine-lncRNA signature was a robust and effective model in predicting DRFS of patients with HER2-negative breast cancer following taxane and anthracycline-based neoadjuvant chemotherapy. 10.1016/j.bcp.2020.114285
Circulating lncRNA H19 may be a useful marker of response to neoadjuvant chemotherapy in breast cancer. Özgür Emre,Ferhatoğlu Ferhat,Şen Fatma,Saip Pinar,Gezer Ugur Cancer biomarkers : section A of Disease markers BACKGROUND:Novel biomarkers are needed to predict the effectiveness of the treatment of presurgical neoadjuvant chemotherapy (NAC) in breast cancer (BC). OBJECTIVE:This is an exploratory study to assess the impact of 3 cancer-related long non-coding RNAs (lncRNAs) (H19, MALAT1 and GA5) in blood plasma of patients with BC in predicting the response to NAC. METHODS:The plasma levels of RNAs were relatively measured by quantitative PCR at baseline, and at the end of the fourth cycle of NAC in patients with locally advanced BC. RESULTS:Only H19 was associated with patients' characteristics, and with the response to NAC. Higher plasma expression of H19 was associated with younger age at diagnosis, triple negative tumors, and Ki-67 index. Patients with a pathological complete response (20%) had lower pre-therapeutic levels of H19 compared with the non-complete responders (relative levels 0.1 vs 0.2, respectively, P: 0.04). In addition, the patients with higher degree of downstaging of initial tumors had lower baseline levels of H19 among non-complete responders. CONCLUSION:Our study reveals that H19, but not MALAT1 and GAS5, may be a useful marker of response to NAC in BC. 10.3233/CBM-190085
Clinical significance of SPRY4-IT1 in efficacy and survival prediction in breast cancer patients undergoing neoadjuvant chemotherapy. Zheng Ang,Zhang Lin,Song Xinyue,Jin Feng Histology and histopathology Breast cancer is the most frequent malignancy and the leading cause of cancer death among females. Long noncoding RNAs (lncRNAs) are under investigation as novel prognostic biomarkers in cancer. The aim of the study was to investigate the expression, clinical implications and prognostic significance of lncRNA SPRY4-IT1, and to identify the predictive value of SPRY4-IT1 on the outcome of chemotherapy in breast cancer patients undergoing neoadjuvant chemotherapy (NACT). Bioinformatics indicated SPRY4-IT1 was related to chemo-resistance in breast cancer. SPRY4-IT1 expression was assessed by qRT-PCR in breast cancer tissues and matched normal breast tissues (n=26 pairs). SPRY4-IT1 expression was also detected by In situ hybridization (ISH) in 60 paraffin slices with complete clinical datum. In this study, SPRY4-IT1 was significantly more expressed in cancer tissues than in normal tissues (P<0.05). Increased SPRY4-IT1 expression was significantly corre¬lated with increased rates of lymph node metastasis (P=0.002) and recurrence (P=0.017). Both were independent factors of SPRY4-IT1 expression (P<0.05). High-SPRY4-IT1 patients had significantly lower overall survival and disease-free survival. High SPRY4-IT1 expression indicated poor clinical response in the whole group, luminal A subgroup and luminal B subgroup (P<0.05) and pathological complete response in the whole group. Overexpression of SPRY4-IT1 promoted chemo-resistance of MCF-7 and MDA-MB-231 cells to epirubicin. SPRY4-IT1 has the potential to be a biomarker to predict NACT efficacy and prognosis in breast cancer patients. 10.14670/HH-18-175
Research Progress on Long Non-coding RNAs and Drug Resistance of Breast Cancer. Zhang Xiping,Yang Hongjian Clinical breast cancer Breast cancer, as the foremost cause of women's death in the world, is highly metastatic and mutable. Resistance to drugs for chemotherapies, endocrine therapies, and targeted therapies is an important factor that impacts the prognosis of breast cancer. Long non-coding ribonucleic acids (LncRNAs) are crucial regulators of intracellular gene expressions. Some researchers have suggested that expression level of several types of LncRNAs were closely related to the prognosis of patients with breast cancer. LncRNAs significantly impact biological processes such as drug transport, detoxication, apoptosis, epithelial to mesenchymal transition (EMT), and autophagy by regulating intracellular signaling pathways such as multi-drug resistance gene 1 (MDR1), nuclear factor erythroid 2-related factor 2 (NRF2), phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR), transforming growth factor-β (TGF-β), BRCA1/2, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). This paper will summarize research progress on correlations between LncRNA and drug resistance of breast cancer. It will particularly expound molecular mechanisms through which LncRNAs regulate drug resistance of breast cancer. It will further discuss the feasibility as molecular markers for forecasting drug resistance of breast cancer and may be becoming new targets for treating breast cancer in the future. 10.1016/j.clbc.2019.11.001
Chemoresistance‑related long non‑coding RNA expression profiles in human breast cancer cells. Huang Lei,Zeng Lihua,Chu Jiahui,Xu Pengfei,Lv Mingming,Xu Juan,Wen Juan,Li Wenqu,Wang Luyu,Wu Xiaowei,Fu Ziyi,Xie Hui,Wang Shui Molecular medicine reports Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death in females worldwide. Chemoresistance has been a major reason for the drug therapy failure. The present study performed a microarray analysis between MCF‑7 and MCF‑7/adriamycin (ADR) cells, and intended to identify long non‑coding (lnc)RNA expression character in drug resistant breast cancer cells. MCF‑7/ADR cells were induced from MCF‑7 cells via pulse‑selection with doxorubicin for 4 weeks, and the resistance to doxorubicin of ADR cells was confirmed by MTT assay. Microarray analysis was performed between MCF‑7 and MCF‑7/ADR cells. Total RNA was extracted from the two cell lines respectively and was transcribed into cDNA. The results of the microarray were verified by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). Gene Ontology (GO) and pathways analysis were conducted to enrich the dysregulated lncRNAs presented in the microarray results. Compared to the MCF‑7 cells, 8,892 lncRNAs were differentially expressed in MCF/ADR cells (absolute fold‑change >2.0). A total of 32 lncRNAs were selected for RT‑qPCR by fold‑change filtering, standard Student's t‑test, and multiple hypothesis testing. Among the dysregulated lncRNAs, AX747207 was prominent because its associated gene RUNX3 was previously reported to be relative to malignant tumor chemoresistance. GO analysis results also indicated some biological processes and molecular functions linked to chemoresistance. The pathway enrichment results provided some potential pathways associated with chemoresistance. In the present study, the authors intended to identify lncRNA expression character in drug resistant cell line MCF‑7/ADR, corresponding to the parental MCF‑7 cell line. In addition, the study identified the lncRNA AX747207, and its potential targeted gene RUNX3, may be related to chemoresistance in breast cancer. These results may new insights into exploring the mechanisms of chemoresistance in breast cancer. 10.3892/mmr.2018.8942
Long noncoding RNA LINP1 acts as an oncogene and promotes chemoresistance in breast cancer. Liang Yiran,Li Yaming,Song Xiaojin,Zhang Ning,Sang Yuting,Zhang Hanwen,Liu Ying,Chen Bing,Zhao Wenjing,Wang Lijuan,Guo Renbo,Yu Zhigang,Yang Qifeng Cancer biology & therapy Recent studies have shown that long non-coding RNAs (lncRNAs) are involved in a number of biological processes; however, further study is still warranted to comprehensively reveal their functions. In this study, we showed that the lncRNA in non-homologous end joining (NHEJ) pathway 1 (LINP1) was related to breast cancer cell proliferation, metastasis and chemoresistance. Loss- and gain-of function studies were used to assess the role of LINP1 in promoting breast cancer progression. LINP1 knockdown mitigated breast cancer cell growth by inducing G1-phase cell cycle arrest and apoptosis. LINP1 also promoted breast cancer cell metastasis and influenced the expression of epithelial-mesenchymal transition-related markers. We identified p53 as a regulator of LINP1, and LINP1 overexpression could restore the metastatic effects of p53. Furthermore, LINP1 was upregulated in doxorubicin- and 5-fluorouracil-resistant cells and induced chemoresistance. We also observed that LINP1 enrichment played a critical functional role in chemoresistance by inhibiting chemotherapeutics-induced apoptosis. Moreover, LINP1 in tumors was associated with lower overall survival and disease-free survival. In conclusion, LINP1 may serve as a potential oncogene and chemoresistance-related regulator of breast cancer cells, suggesting that LINP1 might be a potent therapeutic target and might reduce chemoresistance in breast cancer. 10.1080/15384047.2017.1394543
Long noncoding RNA cancer susceptibility candidate 9 promotes doxorubicin‑resistant breast cancer by binding to enhancer of zeste homolog 2. Jiang Baohong,Li Yuehua,Qu Xiaofei,Zhu Hongbo,Tan Yeru,Fan Qun,Jiang Yiling,Liao Mingchu,Wu Xiaoping International journal of molecular medicine The present study aimed to investigate the effect of the long noncoding RNA cancer susceptibility candidate 9 (CASC9) on doxorubicin (DOX)‑resistant breast cancer and to reveal the potential underlying mechanisms. The expression of CASC9 in breast cancer tissues and cell lines, in addition to drug‑resistant breast cancer cells (MCF‑7/DOX), was detected by reverse transcription‑quantitative polymerase chain reaction. Subsequently, MCF‑7/DOX cells were transfected with the silencing vector pS‑CASC9, containing enhancer of zeste homolog 2 (EZH2), multidrug resistance protein 1 (MDR1) or control small interfering (si)RNAs. The viability, apoptosis, migration and invasion of the transfected cells were assessed via an MTT assay, flow cytometry and a Transwell assay, respectively. The expression levels of apoptosis‑associated proteins (apoptosis regulator Bcl‑2, apoptosis regulator BAX, caspase‑3 and caspase‑9) were determined by western blotting. An RNA pull‑down assay was performed to identify CASC9‑binding candidates. In addition, the expression levels of the MDR1 gene and its encoded protein, P‑glycoprotein, were detected. CASC9 expression was upregulated in breast cancer tissues and cell lines, and drug‑resistant breast cancer cells. CASC9 knockdown significantly inhibited the growth and metastasis of drug‑resistant breast cancer cells, and decreased the half‑maximal inhibitory concentration DOX in MCF‑7/DOX cells. The RNA pull‑down assay revealed that CASC9 engaged EZH2; EZH2 siRNA significantly inhibited the cell growth, metastasis and chemoresistance of MCF‑7/DOX cells. Additionally, EZH2 may regulate the MDR1 gene. The present study demonstrated the oncogenic role of CASC9 in drug‑resistant breast cancer by binding to EZH2 and regulating the MDR1 gene. Modulation of CASC9 expression may be a promising target in the therapy of breast cancer and drug‑resistant breast cancer. 10.3892/ijmm.2018.3812
Exosome-mediated transfer of long noncoding RNA H19 induces doxorubicin resistance in breast cancer. Wang Xinxing,Pei Xinhong,Guo Guangcheng,Qian Xueke,Dou Dongwei,Zhang Zhe,Xu Xiaodong,Duan Xin Journal of cellular physiology Development of the acquired resistance is one major obstacle during chemotherapy for cancer patients. Exosomes mediate intercellular communication and cause environmental changes in tumor progression by transmitting active molecules. In this study, the role of long noncoding RNA H19 within exosomes is elucidated in terms of regulating doxorubicin (DOX) resistance of breast cancer. As a result, increased H19 expression was observed in DOX-resistant breast cancer cells in comparison with the corresponding parental cells. Suppression of H19 significantly lowered DOX resistance by decreasing cell viability, lowering colony-forming ability, and inducing apoptosis. Moreover, extracellular H19 could be moved to sensitive cells via being incorporated into exosomes. Treating sensitive cells with exosomes from resistant cells increased the chemoresistance of DOX, while downregulation of H19 in sensitive cells abated this effect. Taken together, H19 could be delivered by exosomes to sensitive cells, leading to the dissemination of DOX resistance. Our finding highlights the potential of exosomal H19 as a molecular target to reduce DOX resistance. 10.1002/jcp.29585
miR-638 mediated regulation of BRCA1 affects DNA repair and sensitivity to UV and cisplatin in triple-negative breast cancer. Tan Xiaohui,Peng Jin,Fu Yebo,An Shejuan,Rezaei Katayoon,Tabbara Sana,Teal Christine B,Man Yan-gao,Brem Rachel F,Fu Sidney W Breast cancer research : BCR INTRODUCTION:Triple-negative breast cancer (TNBC) represents 15 to 20% of all types of breast cancer; however, it accounts for a large number of metastatic cases and deaths, and there is still no effective treatment. The deregulation of microRNAs (miRNAs) in breast cancer has been widely reported. We previously identified that miR-638 was one of the most deregulated miRNAs in breast cancer progression. Bioinformatics analysis revealed that miR-638 directly targets BRCA1. The aim of this study was to investigate the role of miR-638 in breast cancer prognosis and treatment. METHODS:Formalin-fixed, paraffin-embedded (FFPE) breast cancer samples were microdissected into normal epithelial and invasive ductal carcinoma (IDC) cells, and total RNA was isolated. Several breast cancer cell lines were used for the functional analysis. miR-638 target genes were identified by TARGETSCAN-VERT 6.2 and miRanda. The expression of miR-638 and its target genes was analyzed by real-time qRT-PCR and Western blotting. Dual-luciferase reporter assay was employed to confirm the specificity of miR-638 target genes. The biological function of miR-638 was analyzed by MTT chemosensitivity, matrigel invasion and host cell reactivation assays. RESULTS:The expression of miR-638 was decreased in IDC tissue samples compared to their adjacent normal controls. The decreased miR-638 expression was more prevalent in non-TNBC compared with TNBC cases. miR-638 expression was significantly downregulated in breast cancer cell lines compared to the immortalized MCF-10A epithelial cells. BRCA1 was predicted as one of the direct targets of miR-638, which was subsequently confirmed by dual-luciferase reporter assay. Forced expression of miR-638 resulted in a significantly reduced proliferation rate as well as decreased invasive ability in TNBC cells. Furthermore, miR-638 overexpression increased sensitivity to DNA-damaging agents, ultraviolet (UV) and cisplatin, but not to 5-fluorouracil (5-FU) and epirubicin exposure in TNBC cells. Host cell reactivation assays showed that miR-638 reduced DNA repair capability in post UV/cisplatin-exposed TNBC cells. The reduced proliferation, invasive ability, and DNA repair capabilities are associated with downregulated BRCA1 expression. CONCLUSIONS:Our findings suggest that miR-638 plays an important role in TNBC progression via BRCA1 deregulation. Therefore, miR-638 might serve as a potential prognostic biomarker and therapeutic target for breast cancer. 10.1186/s13058-014-0435-5
Improving breast cancer sensitivity to paclitaxel by increasing aneuploidy. Rodrigues-Ferreira Sylvie,Nehlig Anne,Moindjie Hadia,Monchecourt Clarisse,Seiler Cynthia,Marangoni Elisabetta,Chateau-Joubert Sophie,Dujaric Marie-Eglantine,Servant Nicolas,Asselain Bernard,de Cremoux Patricia,Lacroix-Triki Magali,Arnedos Monica,Pierga Jean-Yves,André Fabrice,Nahmias Clara Proceedings of the National Academy of Sciences of the United States of America Predictive biomarkers for tumor response to neoadjuvant chemotherapy are needed in breast cancer. This study investigates the predictive value of 280 genes encoding proteins that regulate microtubule assembly and function. By analyzing 3 independent multicenter randomized cohorts of breast cancer patients, we identified 17 genes that are differentially regulated in tumors achieving pathological complete response (pCR) to neoadjuvant chemotherapy. We focused on the gene, whose major product, ATIP3, is a microtubule-associated protein down-regulated in aggressive breast tumors. We show here that low levels of ATIP3 are associated with an increased pCR rate, pointing to ATIP3 as a predictive biomarker of breast tumor chemosensitivity. Using preclinical models of patient-derived xenografts and 3-dimensional models of breast cancer cell lines, we show that low ATIP3 levels sensitize tumors to the effects of taxanes but not DNA-damaging agents. ATIP3 silencing improves the proapoptotic effects of paclitaxel and induces mitotic abnormalities, including centrosome amplification and multipolar spindle formation, which results in chromosome missegregation leading to aneuploidy. As shown by time-lapse video microscopy, ATIP3 depletion exacerbates cytokinesis failure and mitotic death induced by low doses of paclitaxel. Our results favor a mechanism by which the combination of ATIP3 deficiency and paclitaxel treatment induces excessive aneuploidy, which in turn results in elevated cell death. Together, these studies highlight ATIP3 as an important regulator of mitotic integrity and a useful predictive biomarker for a population of chemoresistant breast cancer patients. 10.1073/pnas.1910824116
Regulation of apoptosis by long non-coding RNA GAS5 in breast cancer cells: implications for chemotherapy. Pickard Mark R,Williams Gwyn T Breast cancer research and treatment The putative tumour suppressor and apoptosis-promoting gene, growth arrest-specific 5 (GAS5), encodes long ncRNA (lncRNA) and snoRNAs. Its expression is down-regulated in breast cancer, which adversely impacts patient prognosis. In this preclinical study, the consequences of decreased GAS5 expression for breast cancer cell survival following treatment with chemotherapeutic agents are addressed. In addition, functional responses of triple-negative breast cancer cells to GAS5 lncRNA are examined, and mTOR inhibition as a strategy to enhance cellular GAS5 levels is investigated. Breast cancer cell lines were transfected with either siRNA to GAS5 or with a plasmid encoding GAS5 lncRNA and the effects on breast cancer cell survival were determined. Cellular responses to mTOR inhibitors were evaluated by assaying culture growth and GAS5 transcript levels. GAS5 silencing attenuated cell responses to apoptotic stimuli, including classical chemotherapeutic agents; the extent of cell death was directly proportional to cellular GAS5 levels. Imatinib action in contrast, was independent of GAS5. GAS5 lncRNA promoted the apoptosis of triple-negative and oestrogen receptor-positive cells but only dual PI3K/mTOR inhibition was able to enhance GAS5 levels in all cell types. Reduced GAS5 expression attenuates apoptosis induction by classical chemotherapeutic agents in breast cancer cells, providing an explanation for the relationship between GAS5 expression and breast cancer patient prognosis. Clinically, this relationship may be circumvented by the use of GAS5-independent drugs such as imatinib, or by restoration of GAS5 expression. The latter may be achieved by the use of a dual PI3K/mTOR inhibitor, to improve apoptotic responses to conventional chemotherapies. 10.1007/s10549-014-2974-y
[Erratum] Chemoresistance‑related long non‑coding RNA expression profiles in human breast cancer cells. Huang Lei,Zeng Lihua,Chu Jiahui,Xu Pengfei,Lv Mingming,Xu Juan,Wen Juan,Li Wenqu,Wang Luyu,Wu Xiaowei,Fu Ziyi,Xie Hui,Wang Shui Molecular medicine reports Subsequently to the publication of this article, the authors have noted that the second and third named authors on the paper, Lihua Zeng and Jiahui Chu, were not accredited as being joint first authors on this paper, and equal contributors with Lei Huang. The elimination of the necessary asterisks occurred during the pre‑press stages. Therefore, the correct author affliations for this article should have appeared as follows: Lei Huang1,2*, Lihua Zeng3*, Jiahui Chu1*, Pengfei Xu3, Mingming Lv3, Juan Xu3, Juan Wen3, Wenqu Li3, Luyu Wang4, Xiaowei Wu5, Ziyi Fu3, Hui Xie1 and Shui Wang1. 1Department of Breast Surgery, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029; 2Department of General Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, Jiangsu 210008; 3Nanjing Maternity and Child Health Medical Institute, Affiliated Nanjing Maternal and Child Health Hospital, Nanjing Medical University, Nanjing, Jiangsu 210004; 4Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004; 5Department of Pharmacology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China. *Contributed equally. The Editor apologizes to the authors for this oversight on our part, and for the inconvenience caused. [the original article was published in Molecular Medicine Reports 18: 243‑253, 2018; DOI: 10.3892/mmr.2018.8942]. 10.3892/mmr.2019.10003
Long noncoding RNA CASC2 promotes paclitaxel resistance in breast cancer through regulation of miR-18a-5p/CDK19. Zheng Pengfei,Dong Liangpeng,Zhang Bin,Dai Jinfang,Zhang Yifu,Wang Yanan,Qin Shuang Histochemistry and cell biology Breast cancer is one of the most prevalent cancers in women. Chemoresistance is a major obstacle for the treatment of breast cancer. We investigated the role of long noncoding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) in paclitaxel (PTX) resistance in breast cancer. CASC2 expression was increased in PTX-resistant clinical samples and cell lines. PTX induced CASC2 expression in a concentration-dependent manner. Downregulation of CASC2 increased PTX toxicity and decreased IC50 value, while upregulation of CASC2 decreased PTX toxicity and increased IC50 value in MCF-7/PTX and MDA-MB-231/PTX cells. Moreover, downregulation of CASC2 decreased tumor growth in xenograft mice implanted with MCF-7/PTX cells. miR-18a-5p possessed a putative binding site in 3'-UTR of CASC2 and cyclin-dependent kinase 19 (CDK19). In PTX-resistant breast cancer cells, miR-18a-5p expression was decreased. CASC2 and miR-18a-5p could negatively regulate the expression of each other. CDK19 expression could be negatively regulated by miR-18a-5p, but positively regulated by CASC2. miR-18a-5p mimics or downregulation of CDK19 decreased tumor growth in xenograft mice implanted with MCF-7/PTX cells. In summary, we identified that CASC2 activated PTX resistance in breast cancer through regulation of miR-18a-5p/CDK19. We highlight the importance of CASC2/miR-18a-5p/CDK19 axis in the chemoresistance of breast cancer and provide potential targets for the improving chemotherapy of breast cancer. 10.1007/s00418-019-01794-4
Circulating non‑coding RNA‑biomarker potential in neoadjuvant chemotherapy of triple negative breast cancer? Ritter Andrea,Hirschfeld Marc,Berner Kai,Rücker Gerta,Jäger Markus,Weiss Daniela,Medl Markus,Nöthling Claudia,Gassner Sandra,Asberger Jasmin,Erbes Thalia International journal of oncology Due to the positive association between neoadjuvant chemotherapy (NACT) and the promising early response rates of patients with triple negative breast cancer (TNBC), including probabilities of pathological complete response, NACT is increasingly used in TNBC management. Liquid biopsy‑based biomarkers with the power to diagnose the early response to NACT may support established monitoring tools, which are to a certain extent imprecise and costly. Simple serum‑ or urine‑based analyses of non‑coding RNA (ncRNA) expression may allow for fast, minimally‑invasive testing and timely adjustment of the therapy regimen. The present study investigated breast cancer‑related ncRNAs [microRNA (miR)‑7, ‑9, ‑15a, ‑17, ‑18a, ‑19b, ‑21, ‑30b, ‑222 and ‑320c, PIWI‑interacting RNA‑36743 and GlyCCC2] in triple positive BT‑474 cells and three TNBC cell lines (BT‑20, HS‑578T and MDA‑MB‑231) treated with various chemotherapeutic agents using reverse transcription‑quantitative PCR. Intracellular and secreted microvesicular ncRNA expression levels were analysed using a multivariable statistical regression analysis. Chemotherapy‑driven effects were investigated by analysing cell cycle determinants at the mRNA and protein levels. Serum and urine specimens from 8 patients with TNBC were compared with 10 healthy females using two‑sample t‑tests. Samples from the patients with TNBC were compared at two time points. Chemotherapeutic treatments induced distinct changes in ncRNA expression in TNBC cell lines and the BT‑474 cell line in intra‑ and extracellular compartments. Serum and urine‑based ncRNA expression analysis was able to discriminate between patients with TNBC and controls. Time point comparisons in the urine samples of patients with TNBC revealed a general rise in the level of ncRNA. Serum data suggested a potential association between piR‑36743, miR‑17, ‑19b and ‑30b expression levels and an NACT‑driven complete clinical response. The present study highlighted the potential of ncRNAs as liquid biopsy‑based biomarkers in TNBC chemotherapy treatment. The ncRNAs tested in the present study have been previously investigated for their involvement in BC or TNBC chemotherapy responses; however, these previous studies were restricted to patient tissue or in vitro models. The data from the present study offer novel insight into ncRNA expression in liquid samples from patients with TNBC, and the study serves as an initial step in the evaluation of ncRNAs as diagnostic biomarkers in the monitoring of TNBC therapy. 10.3892/ijo.2019.4920
A Minimal lncRNA-mRNA Signature Predicts Sensitivity to Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer. Wang Qian,Li Chunmei,Tang Peipei,Ji Runyuan,Chen Song,Wen Jian Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology BACKGROUND/AIMS:Triple-negative breast cancer (TNBC) is a highly aggressive malignancy that responds in a diverse manner to neoadjuvant chemotherapy (NAC). This study was aimed to uncover an RNA signature in TNBC patients which predicts pathological complete responses (pCR) to NAC by analyzing long noncoding RNA (lncRNA) and coding gene expression. METHODS:Microarray datasets from 26 TNBC patients receiving NAC including ten patients showing pCR were obtained from the Gene Expression Omnibus database. RESULTS:A total of 172 coding genes and 84 lncRNAs were differentially expressed between patients achieving pCR and those who did not. Filtering based on the predictive efficacy of response to NAC using receiver operator characteristic curve (ROC) and area under the curve (AUC) shortlisted 23 lncRNAs and 15 coding genes from consideration. Finally, a response score consisting of 1 lncRNA and 2 coding genes was developed: response score = 2.595*BPESC1 - 1.09*WDR72 -1.428*GADD45A - 0.731. The response score had good predictive performance (AUC=0.931, p< 0.01) and at the cut-off of 0.545, the response score had sensitivity and specificity of 0.8 and 0.9, respectively. CONCLUSION:We propose a simple gene expression signature of only three RNA species could be employed clinically to predict pCR in TNBC patients receiving NAC. 10.1159/000492698
Long noncoding RNA MIAT regulates apoptosis and the apoptotic response to chemotherapeutic agents in breast cancer cell lines. Almnaseer Zainab A,Mourtada-Maarabouni M Bioscience reports The long noncoding RNA myocardial infarction associated transcript (MIAT) is involved in a number of diseases, including myocardial infarction and diabetic retinopathy. Emerging evidence suggests that MIAT expression levels are increased in different type of cancers, including breast cancer. In the present study, we further evaluated the role of MIAT in breast cancer and investigated the consequences of its silencing on breast cancer response to chemotherapeutic agents. Expression levels of MIAT mRNA in breast cancer were determined using TissueScan™ Breast Cancer cDNA Arrays. Breast cancer cell lines were transfected with MIAT specific siRNAs, with silencing confirmed using RT-qPCR and the effects on breast cancer cell survival and response to different apoptotic stimuli determined. MIAT transcript levels were significantly elevated in breast cancer samples. Such increase was specific to the early stages of the disease, ER, PR +ve, HER -ve, and triple negative breast cancer samples. Silencing of MIAT induced growth arrest and increased basal apoptosis. Reduced levels of MIAT augmented the apoptotic response of breast cancer cells to a wide range of apoptotic stimuli. Our results also showed that MIAT down-regulation was associated with a decrease in OCT4 mRNA, suggesting the existence of a MIAT/OCT4 regulatory loop, similar to that observed in malignant mature B cells. Taken together with the recent demonstration of oncogene characteristics, our observations suggest that MIAT plays an important role in breast tumorigenesis. Strategies to decrease MIAT expression levels may improve sensitivity to therapy in breast cancer by enhancing the apoptotic responses to conventional chemotherapies. 10.1042/BSR20180704
Effects of miRNAs on functions of breast cancer stem cells and treatment of breast cancer. Zhang Ying,Xu Bin,Zhang Xi-Ping OncoTargets and therapy Breast cancer is one of the most common malignancies for women, which accounts for 30% of all female malignancies. The formation of breast cancer stem cells (BCSCs) is attributed to the acquisition of stemness of tumor cells. With self-renewal potential, these stem cells are insensitive to either radiotherapy or chemotherapy but are significant in regulating tumor behaviors and drug resistance. MicroRNA (miRNA) is a kind of noncoding small RNA for negatively regulating gene expressions. Research findings suggest that many miRNAs specifically regulate the expression of target genes and signal pathways of BCSCs. They play an important role in self-renewal, growth, and metastasis of breast cancer cells as potential targets for treating breast cancer. These signal pathways include phosphatase and tensin homolog deleted on chromosome 10-phosphatidylinositol 3-kinase/Akt, Wnt/β-catenin, Notch, and so on. This paper reviews the progress of research about miRNAs in self-renewal, metastasis, epithelial-mesenchymal transition and metastasis, mediation of resistance to chemotherapies, and treatment of breast cancer. 10.2147/OTT.S165156
Inferences of individual drug responses across diverse cancer types using a novel competing endogenous RNA network. Zhang Yan,Li Xin,Zhou Dianshuang,Zhi Hui,Wang Peng,Gao Yue,Guo Maoni,Yue Ming,Wang Yanxia,Shen Weitao,Ning Shangwei,Li Yixue,Li Xia Molecular oncology Differences in individual drug responses are an obstacle to progression in cancer treatment, and predicting responses would help to plan treatment. The accumulation of cancer molecular profiling and drug response data provides opportunities and challenges to identify novel molecular signatures and mechanisms of tumor responsiveness to drugs. This study evaluated drug responses with a competing endogenous RNA (ceRNA) system that depended on competition between diverse RNA species. We identified drug response-related ceRNA (DRCEs) by combining the sequence and expression data of long noncoding RNA (lncRNA), microRNA (miRNA), and messenger RNA (mRNA), and the survival data of cancer patients treated with drugs. We constructed a patient-drug two-layer integrated network and used a linear weighting method to predict individual drug responses. DRCEs were found to be significantly enriched in known cancer and drug-associated data resources, involved in biological processes known to mediate drug responses, and correlated to drug activity in cancer cell lines. The dysregulation of DRCE expression influenced drug response-associated functions and pathways, suggesting DRCEs as potential therapeutic targets affecting drug responses. A further case study in breast invasive carcinoma (BRCA) found that DRCE expression was consistent with the drug response pattern and the aberrant expression of the two NEAT1-related DRCEs may lead to poor response to tamoxifen therapy for patients with TP53 mutations. In summary, this study provides a framework for ceRNA-based evaluation of clinical drug responses across multiple cancer types. Understanding the underlying molecular mechanisms of drug responses will allow improved response to chemotherapy and outcomes of cancer treatment. 10.1002/1878-0261.12181
Circulating MiR-125b as a marker predicting chemoresistance in breast cancer. Wang Hongjiang,Tan Guang,Dong Lei,Cheng Lei,Li Kejun,Wang Zhongyu,Luo Haifeng PloS one BACKGROUND:Chemotherapy is an important component in the treatment paradigm for breast cancers. However, the resistance of cancer cells to chemotherapeutic agents frequently results in the subsequent recurrence and metastasis. Identification of molecular markers to predict treatment outcome is therefore warranted. The aim of the present study was to evaluate whether expression of circulating microRNAs (miRNAs) can predict clinical outcome in breast cancer patients treated with adjuvant chemotherapy. METHODOLOGY/PRINCIPAL FINDINGS:Circulating miRNAs in blood serum prior to treatment were determined by quantitative Real-Time PCR in 56 breast cancer patients with invasive ductal carcinoma and pre-operative neoadjuvant chemotherapy. Proliferating cell nuclear antigen (PCNA) immunostaining and TUNEL were performed in surgical samples to determine the effects of chemotherapy on cancer cell proliferation and apoptosis, respectively. Among the miRNAs tested, only miR-125b was significantly associated with therapeutic response, exhibiting higher expression level in non-responsive patients (n = 26, 46%; p = 0.008). In addition, breast cancers with high miR-125b expression had higher percentage of proliferating cells and lower percentage of apoptotic cells in the corresponding surgical specimens obtained after neoadjuvant chemotherapy. Increased resistance to anticancer drug was observed in vitro in breast cancer cells with ectopic miR-125b expression; conversely, reducing miR-125b level sensitized breast cancer cells to chemotherapy. Moreover, we demonstrated that the E2F3 was a direct target of miR-125b in breast cancer cells. CONCLUSIONS/SIGNIFICANCE:These data suggest that circulating miR-125b expression is associated with chemotherapeutic resistance of breast cancer. This finding has important implications in the development of targeted therapeutics for overcoming chemotherapeutic resistance in novel anti-cancer strategies. 10.1371/journal.pone.0034210
Expression of miR-335 in triple-negative breast cancer and its effect on chemosensitivity. Hao Jie,Lai Minghua,Liu Chunsheng Journal of B.U.ON. : official journal of the Balkan Union of Oncology PURPOSE:To investigate the expression of miR-335 in triple-negative breast cancer (TNBC) and its effect on chemosensitivity. METHODS:The expression of miR-335 in cancer tissues and adjacent tissues of 42 patients with TNBC who underwent mastectomy in our hospital was detected by qRT-PCR. Liposome was used to transfect miR-335 mimics (miR-335-mimic) and empty vectors (miR-NC) into cells of TNBC cell line MDA-MB-231, and untransfected cells were used as blank control cells (NC). Three groups of cells were cultured in culture Levbeit's medium supplemented with 2 μmol/L paclitaxel, 5 μmol/L cisplatin and 4 μmol/L doxorubicin. Proliferation rate and apoptosis rate of tumor cells were measured by MTT assay and TUNEL assay 48 h after transfection. RESULTS:The relative expression level of miR-335 in cancer tissues was significantly lower than that in adjacent tissues of TNBC patients (p<0.05). After paclitaxel, cisplatin and doxorubicin treatment, the proliferation and apoptosis rates of the three groups were statistically different (p<0.05). There was no significant difference in cell proliferation rate and apoptosis rate between NC group and miR-NC group (p>0.05), but the proliferation rate of cells was higher and apoptosis rate was lower in the NC group and miR-NC group than that in miR-335-mimic group (p<0.05). CONCLUSION:The expression level of miR-335 in cancer tissues of TNBC patients is lower than that in adjacent tissues. Overexpression of miR-335 can increase the sensitivity of tumor cells to paclitaxel, cisplatin and doxorubicin, and improve the effect of chemotherapy.
MicroRNA in diagnosis and therapy monitoring of early-stage triple-negative breast cancer. Kahraman Mustafa,Röske Anne,Laufer Thomas,Fehlmann Tobias,Backes Christina,Kern Fabian,Kohlhaas Jochen,Schrörs Hannah,Saiz Anna,Zabler Cassandra,Ludwig Nicole,Fasching Peter A,Strick Reiner,Rübner Matthias,Beckmann Matthias W,Meese Eckart,Keller Andreas,Schrauder Michael G Scientific reports Breast cancer is a heterogeneous disease with distinct molecular subtypes including the aggressive subtype triple-negative breast cancer (TNBC). We compared blood-borne miRNA signatures of early-stage basal-like (cytokeratin-CK5-positive) TNBC patients to age-matched controls. The miRNAs of TNBC patients were assessed prior to and following platinum-based neoadjuvant chemotherapy (NCT). After an exploratory genome-wide study on 21 cases and 21 controls using microarrays, the identified signatures were verified independently in two laboratories on the same and a new cohort by RT-qPCR. We differentiated the blood of TNBC patients before NCT from controls with 84% sensitivity. The most significant miRNA for this diagnostic classification was miR-126-5p (two tailed t-test p-value of 1.4 × 10). Validation confirmed the microarray results for all tested miRNAs. Comparing cancer patients prior to and post NCT highlighted 321 significant miRNAs (among them miR-34a, p-value of 1.2 × 10). Our results also suggest that changes in miRNA expression during NCT may have predictive potential to predict pathological complete response (pCR). In conclusion we report that miRNA expression measured from blood facilitates early and minimally-invasive diagnosis of basal-like TNBC. We also demonstrate that NCT has a significant influence on miRNA expression. Finally, we show that blood-borne miRNA profiles monitored over time have potential to predict pCR. 10.1038/s41598-018-29917-2
Downregulation of miR‑200c‑3p contributes to the resistance of breast cancer cells to paclitaxel by targeting SOX2. Chen Junqing,Tian Wei,He Haifei,Chen Feng,Huang Jian,Wang Xiaojia,Chen Zhanhong Oncology reports Acquisition of resistance to paclitaxel is a major obstacle to successful treatment of breast cancer patients, but the molecular mechanisms underlying the development of drug resistance remain largely unclear. The aim of the present study was to investigate the role and mechanism of action of miR‑200c‑3p in the resistance of breast cancer to paclitaxel. It was observed that miR‑200c‑3p expression, as determined by reverse transcription‑quantitative polymerase chain reaction analysis, was significantly downregulated in paclitaxel‑resistant MCF‑7/Tax cells compared with parental MCF‑7 cells. Overexpression of miR‑200c‑3p increased the chemosensitivity to paclitaxel and enhanced apoptosis in MCF‑7/Tax cells, whereas the downregulation of miR‑200c‑3p exerted the opposite effect. In addition, upregulation of miR‑200c‑3p in MCF‑7/Tax cells suppressed the expression of sex‑determining region Y‑box 2 (SOX2) at the mRNA and protein levels. Dual‑luciferase reporter assay demonstrated that SOX2 is a target of miR‑200c‑3p in MCF‑7/Tax cells. Moreover, knockdown of SOX2 expression increased chemosensitivity to paclitaxel and upregulated miR‑200c‑3p expression in MCF‑7/Tax cells. Taken together, the results of the present study indicated that miR‑200c‑3p plays a key role in the development of paclitaxel resistance in breast cancer, possibly partially through regulating SOX2 expression, suggesting that the miR‑200c‑3p‑SOX2 loop may serve as a potential target for the reversal of paclitaxel resistance in breast cancer. 10.3892/or.2018.6735
MiR-487a resensitizes mitoxantrone (MX)-resistant breast cancer cells (MCF-7/MX) to MX by targeting breast cancer resistance protein (BCRP/ABCG2). Ma Meng-Tao,He Miao,Wang Yan,Jiao Xu-Yang,Zhao Lin,Bai Xue-Feng,Yu Zhao-Jin,Wu Hui-Zhe,Sun Ming-Li,Song Zhi-Guo,Wei Min-Jie Cancer letters Breast cancer resistance protein (BCRP/ABCG2) specifically transports various chemotherapeutic agents and is involved in the development of multidrug resistance (MDR) in cancer cells. MicroRNAs (miRNAs) can play an important role in modulating the sensitivity of cancer cells to chemotherapeutic agents. Therefore, after confirming that BCRP was increased in the mitoxantrone (MX)-resistant MCF-7 breast cancer cell line MCF-7/MX compared with its parental sensitive MCF-7 cell line, we aimed to explore the miRNAs that regulate BCRP expression and sensitize breast cancer cells to chemotherapeutic agents. In the present study, bioinformatic analysis indicated that miR-487a was one of the miRNAs that could bind to the 3' untranslated region (3'UTR) of BCRP. Quantitative RT-PCR (qRT-PCR) analysis demonstrated that the expression of miR-487a was reduced in MCF-7/MX cells, and a luciferase reporter assay demonstrated that miR-487a directly bound to the 3'UTR of BCRP. Moreover, ectopic miR-487a down-regulated BCRP expression at the mRNA and protein levels, increasing the intracellular accumulation and cytotoxicity of MX in resistant MCF-7/MX breast cancer cells. Meanwhile, inhibition of miR-487a increased BCRP expression at the mRNA and protein levels and induced MX resistance in sensitive MCF-7 breast cancer cells. Furthermore, the reduced expression of BCRP and increased antitumor effects of MX were also detected in MCF-7/MX xenograft tumors treated with the miR-487a agmir. Thus, our results suggested that miR-487a can directly regulate BCRP expression and reverse chemotherapeutic drug resistance in a subset of breast cancers. 10.1016/j.canlet.2013.07.016
Serum miR-21 and miR-125b as markers predicting neoadjuvant chemotherapy response and prognosis in stage II/III breast cancer. Liu Baoquan,Su Fei,Chen Mingwei,Li Yue,Qi Xiuying,Xiao Jianbing,Li Xuemei,Liu Xiangchen,Liang Wenlong,Zhang Yafang,Zhang Jianguo Human pathology The predictive value of serum miRNAs (ser-miRNA) for the response to neoadjuvant chemotherapy (NCT) and the prognosis of breast cancer patients were investigated in the current study. The study included 118 stage II/III breast cancer patients and 30 healthy adult women. Peripheral blood was drawn from participants before the start (baseline [BL]), at the end of the second cycle (first evaluation during NCT [FEN]), and at the end of NCT (second evaluation during NCT [SEN]). The expression of ser-miRNAs was examined by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and their association with chemotherapy response and prognosis was analyzed. MiR-19a, miR-21, miR-125b, miR-155, miR-205, and miR-373 were significantly up-regulated in the serum of breast cancer patients at BL, miR-451 was significantly down-regulated, and miR-122 was unchanged compared with the levels in healthy women. The expression of ser-miR-125b and the changes of ser-miR-21 expression during NCT were associated with chemotherapy response and disease-free survival (DFS). In chemotherapy responders, ser-miR-125b expression was lower than that of non-responders at BL, FEN, and SEN, and ser-miR-21 levels decreased from BL to FEN and from BL to SEN. Survival analysis showed that patients with lower ser-miR-125b expression at BL, FEN, and SEN had favorable DFS, and those with decreased ser-miR-21 expression from BL to FEN and from BL to SEN had better DFS. In conclusion, ser-miR-21 and ser-miR-125b were identified as novel, noninvasive predictive markers for NCT response and prognosis in breast cancer. 10.1016/j.humpath.2017.03.016
miR-27a regulates the sensitivity of breast cancer cells to cisplatin treatment via BAK-SMAC/DIABLO-XIAP axis. Zhou Sumei,Huang Qidi,Zheng Shurong,Lin Kuailu,You Jie,Zhang Xiaohua Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine MicroRNA-27a (miR-27a) has been reported to be an onco-microRNA in multiple cancers promoting tumor growth and metastasis, but the role of miR-27a in regulating the cancer sensitivity to chemotherapy remains unknown. In this study, upregulation of miR-27a was validated by real-time PCR analysis in breast cancer (BC) cell lines and samples of BC patients. A negative correlation between miR-27a and bak was also observed in normal breast epithelial cell line MCF-10A and BC cell lines, suggesting that the bak is the potential target of miR-27a. miR-27a could modulate the growth and metastasis of BC cells. More importantly, we found that knockdown of miR-27a by the specific inhibitors significantly increased the sensitivity of T-47D cells to cisplatin (CDDP) treatment. After further investigation, we indicated that the knockdown of miR-27a promoted the apoptosis via mitochondrial pathway in T-47D cells treated with CDDP, depending on the BAK-second mitochondria-derived activator of caspase/direct IAP binding protein with low pI (SMAC/DIABLO)-X-linked inhibitor of apoptosis (XIAP) axis. Interestingly, we found that the sensitivity of T-47D cells to some other chemotherapeutic agents (5-fluorouracil, doxorubicin, and tumor necrosis factor-related apoptosis-inducing ligand) was also regulated by miR-27a. These findings improve our understanding of the role of miR-27a in breast cancer and might provide a novel strategy for cancer therapy. 10.1007/s13277-015-4500-1