Persistent activation of STAT3 by PIM2-driven positive feedback loop for epithelial-mesenchymal transition in breast cancer.
Cancer science
Metastasis of breast cancer is promoted by epithelial-mesenchymal transition (EMT). Emerging evidence suggests that STAT3 is a critical signaling node in EMT and is constitutively activated in many carcinomas, including breast cancer. However, its signaling mechanisms underlying persistent activation of STAT3 associated with EMT remain obscure. Here, we report that PIM2 promotes activation of STAT3 through induction of cytokines. Activation of STAT3 caused an increase in PIM2 expression, implicating a positive feedback loop between PIM2 and STAT3. In agreement, targeting of either PIM2, STAT3 or PIM2-dependent cytokines suppressed EMT-associated migratory and invasive properties through inhibition of ZEB1. Taken together, our findings identify the signaling mechanisms underlying the persistent activation of STAT3 and the oncogenic role of PIM2 in EMT in breast cancer.
10.1111/cas.12668
UBE2O promotes the proliferation, EMT and stemness properties of breast cancer cells through the UBE2O/AMPKα2/mTORC1-MYC positive feedback loop.
Liu Xu,Ma Fei,Liu Chunxiao,Zhu Kaiyuan,Li Wenjie,Xu Yuting,Li Ge,Niu Zhenbo,Liu Jiaxin,Chen Du,Li Zhigao,Fu Yingqiang,Qian Cheng
Cell death & disease
Ubiquitin-conjugating enzyme E2O (UBE2O) is a large E2 ubiquitin-conjugating enzyme that possesses both E2 and E3 ligase activities. Ectopic UBE2O overexpression is associated with a variety of human diseases, especially cancers. However, the expression profile and functional biology of UBE2O in human breast cancer (BC) remain unclear. In this study, we found that UBE2O was significantly overexpressed in human BC tissues and cells. Patients with high UBE2O expression tended to have a high risk of metastasis and poor prognosis. In vitro assays revealed that UBE2O promoted BC cell proliferation and epithelial-mesenchymal transformation (EMT) and endowed BC cells with cancer stemness properties (CSPs). UBE2O knockdown in MDA-MB-231 cells suppressed tumour growth and lung metastasis in MDA-MB-231 xenograft mouse models. Mechanistically, UBE2O functioned as a ubiquitin enzyme of AMPKα2, promoting its ubiquitination and degradation and thus activating the mTORC1 signal pathway and contributing to BC oncogenesis and metastasis. Furthermore, as a downstream factor of the UBE2O/AMPKα2/mTORC1 axis, the oncoprotein MYC transcriptionally promoted UBE2O and formed a positive feedback loop in human BC. Collectively, our study demonstrated that UBE2O/AMPKα2/mTORC1-MYC forms a positive feedback loop in human BC cells that regulates BC cell proliferation and EMT and endows BC cells with CSPs.
10.1038/s41419-019-2194-9
MiR-23a promotes TGF-β1-induced EMT and tumor metastasis in breast cancer cells by directly targeting CDH1 and activating Wnt/β-catenin signaling.
Ma Fei,Li Wenjie,Liu Chunxiao,Li Wei,Yu Haining,Lei Bo,Ren Yanlv,Li Zhigao,Pang Da,Qian Cheng
Oncotarget
TGF-β1-induced epithelial-mesenchymal transition (EMT) has been proved to be associated with metastasis of breast cancer cells. We attempted to detect a novel mechanism that microRNAs mediated the TGF-β1-induced EMT in the process of breast cancer metastasis. Here we reported that the expression of miR-23a was higher in breast cancer cells with high metastasis ability and patients with lymph node metastasis and the treatment of TGF-β1 significantly upregulated the expression of miR-23a in breast cancer cells. We found that miR-23a was upregulated by TGF-β1 post-transcriptionally and Smads directly bound the RNA Smad binding element (R-SBE) of miR-23a. Functional studies showed that inhibition of miR-23a suppressed the TGF-β1-induced EMT, migration, invasion and metastasis of breast cancer both and . In addition, we determined that miR-23a directly targeted and suppressed CDH1, one important gene in EMT phenomenon. Notably, Wnt/β-catenin signaling was activated by the suppression of CDH1 in the miR-23a mediated process of TGF-β1-induced EMT and tumor invasion. These results demonstrate that miR-23a promotes TGF-β1-induced tumor metastasis in breast cancer by targeting CDH1 and activating Wnt/β-catenin signaling. Taken together, our results indicate a novel regulatory mechanism of TGF-β1-induced EMT and suggest that miR-23a might be a potential target in breast cancer therapy.
10.18632/oncotarget.18422
Downregulation of cytokeratin 18 enhances BCRP-mediated multidrug resistance through induction of epithelial-mesenchymal transition and predicts poor prognosis in breast cancer.
Shi Ruizan,Wang Chang,Fu Naijie,Liu Linhong,Zhu Diying,Wei Zehui,Zhang Huifeng,Xing Jianfeng,Wang Yan
Oncology reports
Multiple drug resistance (MDR) and metastasis have been identified as the two major causes of the poor prognosis of patients with breast cancer. However, the relationship between MDR and metastasis has not been characterized. Epithelial‑mesenchymal transition (EMT), a process known to promote metastasis in cancer, has been shown to be associated with the MDR phenotype of many tumor types. Reduced cytokeratin 18 (CK18) expression is thought to be one of the hallmarks of EMT, and the role of CK18 in MDR of metastatic breast cancer remains unknown. In the present study, we revealed that the expression of CK18 was significantly downregulated in breast cancer tissues and in an MDR cell line overexpressing breast cancer resistant protein (BCRP), and the presence of low levels of CK18 was associated with TNM stage, lymph node metastasis, and unfavorable survival in breast cancer patients. Further results demonstrated that CK18 stable knockdown using shRNA increased BCRP expression and induced the EMT process in human breast cancer MCF‑7 cells. Moreover, CK18 knockdown was associated with the activation of the NF‑κB/Snail signaling pathway, which has been revealed to regulate EMT and BCRP. Based on these findings, we concluded that CK18 knockdown enhanced BCRP‑mediated MDR in MCF‑7 cells through EMT induction partly via the NF‑κB/Snail pathway. These findings provide a valuable insight into the potential role of CK18 in MDR, migration and invasion of breast cancer cells. Reduced expression of CK18 may be a novel biomarker for predicting the poor prognosis of breast cancer patients.
10.3892/or.2019.7069
miR-516a-3p inhibits breast cancer cell growth and EMT by blocking the Pygo2/Wnt signalling pathway.
Chi Yanyan,Wang Feng,Zhang Tengfei,Xu Han,Zhang Yana,Shan Zhengzheng,Wu Shaoxuan,Fan Qingxia,Sun Yan
Journal of cellular and molecular medicine
miR-516a-3p has been reported to play a suppressive role in several types of human tumours. However, the expression level, biological function and fundamental mechanisms of miR-516a-3p in breast cancer remain unclear. In the present study, we found that miR-516a-3p expression was down-regulated and Pygopus2 (Pygo2) expression was up-regulated in human breast cancer tissues and cells. Through analysing the clinicopathological characteristics, we demonstrated that low miR-516a-3p expression or positive Pygo2 expression was a predictor of poor prognosis for patients with breast cancer. The results of a dual luciferase reporter assay and Western blot analysis indicated that Pygo2 was a target gene of miR-516a-3p. Moreover, overexpression of miR-516a-3p inhibited cell growth, migration and invasion as well as epithelial-mesenchymal transition (EMT) of breast cancer cells, whereas reduced miR-516a-3p expression promoted breast cancer cell growth, migration, invasion and EMT. Furthermore, we showed that miR-516a-3p suppressed cell proliferation, metastasis and EMT of breast cancer cells by inhibiting Pygo2 expression. We confirmed that miR-516a-3p exerted an anti-tumour effect by inhibiting the activation of the Wnt/β-catenin pathway. Finally, xenograft tumour models were used to show that miR-516a-3p inhibited breast cancer cell growth and EMT via suppressing the Pygo2/Wnt signalling pathway. Taken together, these results show that miR-516a-3p inhibits breast cancer cell growth, metastasis and EMT by blocking the Pygo2/ Wnt/β-catenin pathway.
10.1111/jcmm.14515
Overexpression of KRT17 promotes proliferation and invasion of non-small cell lung cancer and indicates poor prognosis.
Cancer management and research
PURPOSE:Keratin 17 (KRT17) is a 48 KDa type I intermediate filament, which is mainly expressed in epithelial basal cells. KRT17 has been shown to be overexpressed in many malignant tumors and play an important role in the occurrence and development of tumors. Therefore, this study explored the role and underlying mechanism of KRT17 in non-small cell lung cancers (NSCLC). METHODS:KRT17 expression and its correlations with clinicopathological factors were examined in lung cancer tissues by immunohistochemistry. The prognosis value of KRT17 in NSCLCs was retrieved from The Cancer Genome Atlas (TCGA) online databases. The expression level of KRT17 was increased or decreased by KRT17 gene transfection or small RNA interference in lung cancer cells, respectively. Further, proliferation and invasiveness of lung cancer cells were determined by cell proliferation and invasion assays, respectively. Finally, expression levels of proteins related to Wnt signaling pathways and epithelial mesenchymal transition (EMT) were detected by Western blot. RESULTS:The expression level of KRT17 in NSCLCs was significantly higher than normal lung tissues. High expression of KRT17 predicted poor prognosis of patients with NSCLCs, especially lung adenocarcinomas, and was correlated with poor differentiation and lymphatic metastasis. Overexpression of KRT17 enhanced, while KRT17 knockdown inhibited, the proliferation and invasiveness of lung cancer cells. Overexpression of KRT17 up-regulated β-catenin activity and levels of Wnt target genes, such as cyclin D1, c-Myc, and MMP7. Moreover, KRT17 promoted EMT by up-regulating Vimentin, MMP-9, and Snail expression and down-regulating E-cadherin expression. CONCLUSION:Overexpression of KRT17 is common in NSCLCs and indicates poor prognosis. Overexpression of KRT17 enhances the proliferation and invasiveness of NSCLC cells by activating the Wnt signaling pathway and EMT process. KRT17 is a potential indicator of NSCLC progression and poor survival.
10.2147/CMAR.S218926
MicroRNA-148a suppresses epithelial-mesenchymal transition and invasion of pancreatic cancer cells by targeting Wnt10b and inhibiting the Wnt/β-catenin signaling pathway.
Oncology reports
Epithelial-mesenchymal transition (EMT) plays a critical role in the process of cancer invasion and metastasis. The Wnt/β-catenin signaling pathway is known as a stimulative factor, which may trigger EMT and metastasis of cancer cells. In addition, several microRNAs (miRNAs) have been proven to regulate the EMT process. Recent research revealed that miR‑148a is downregulated in pancreatic cancer. However, the definite role of miR-148a in EMT and invasion of pancreatic cancer is still unknown. The present study attempted to demonstrate the underlying mechanism of miR-148a in the regulation of EMT and invasion of pancreatic cancer cells. Our data revealed that the expression of miR-148a was markedly downregulated in human pancreatic ductal adenocarcinoma (PDAC) cell lines and tissues. In addition, the downregulation of miR-148a was associated with poor prognosis and EMT phenotype. Furthermore, restoration of miR-148a expression inhibited the EMT process, as well as the migration and invasion of BxPC-3 pancreatic cancer cells. Wnt10b, a promoting molecule of the Wnt/β-catenin signaling pathway, was demonstrated by dual‑luciferase reporter assay to be a direct target of miR‑148a. Subsequently, we found that miR‑148a negatively regulated the protein expression of β-catenin, cyclin D1 and MMP-9, which were important components of the Wnt/β-catenin signaling pathway. In conclusion, these findings revealed that miR-148a suppresses EMT and invasion of pancreatic cancer cells by targeting Wnt10b and inhibiting the Wnt/β-catenin signaling pathway, and thus, miR-148a may serve as a novel therapeutic target for pancreatic cancer.
10.3892/or.2017.5705
RETRACTED: MiR-361-5p inhibits the mobility of gastric cancer cells through suppressing epithelial-mesenchymal transition via the Wnt/β-catenin pathway.
Gene
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).Several figures presented in the manuscript appear to have been doctored. Figure 1C contains copied areas between the Control group and miR-361-5p mock panels. An area from Figure 1C miR-361-5p mock panel is copied from Figure 2B lncRNA-MEG3 panel from the publication Oncology Reports 39-48, 2018 doi:10.3892/or.2018.6424Figure 1D contains copied areas between the Control group and miR-361-5p mock panels. Figures 1E and 1F show several copied areas between one other. At higher contrast, the western blot presented in Figure 3G shows signs of picture manipulationThe journal has tried to contact the authors of this article but at the time of publication of this notice has not received any explanation for the image manipulations. The Editor-in-Chief of Gene has therefore lost confidence in the validity of this work and has decided to retract it.
10.1016/j.gene.2018.06.095