The RNA helicase p68 is a novel androgen receptor coactivator involved in splicing and is overexpressed in prostate cancer.
Cancer research
The androgen receptor (AR) is a member of the nuclear steroid hormone receptor family and is thought to play an important role in the development of both androgen-dependent and androgen-independent prostatic malignancy. Elucidating roles by which cofactors regulate AR transcriptional activity may provide therapeutic advancement for prostate cancer (PCa). The DEAD box RNA helicase p68 (Ddx5) was identified as a novel AR-interacting protein by yeast two-hybrid screening, and we sought to examine the involvement of p68 in AR signaling and PCa. The p68-AR interaction was verified by colocalization of overexpressed protein by immunofluorescence and confirmed in vivo by coimmunoprecipitation in the PCa LNCaP cell line. Chromatin immunoprecipitation in the same cell line showed AR and p68 recruitment to the promoter region of the androgen-responsive prostate-specific antigen (PSA) gene. Luciferase reporter, minigene splicing assays, and RNA interference (RNAi) were used to examine a functional role of p68 in AR-regulated gene expression, whereby p68 targeted RNAi reduced AR-regulated PSA expression, and p68 enhanced AR-regulated repression of CD44 splicing (P = 0.008). Tyrosine phosphorylation of p68 was found to enhance coactivation of ligand-dependent transcription of AR-regulated luciferase reporters independent of ATP-binding. Finally, we observe increased frequency and expression of p68 in PCa compared with benign tissue using a comprehensive prostate tissue microarray (P = 0.003; P = 0.008). These findings implicate p68 as a novel AR transcriptional coactivator that is significantly overexpressed in PCa with a possible role in progression to hormone-refractory disease.
10.1158/0008-5472.CAN-08-0932
Camptothecin induced DDX5 degradation increased the camptothecin resistance of osteosarcoma.
Zhao Xingkai,Bao Miao,Zhang Fengmin,Wang Wenbo
Experimental cell research
Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. Unfortunately, chemo-resistance is a huge obstacle in the treatment of OS. However, the underlying molecular mechanisms of OS chemo-resistance still remain unknown. Here we reported that the resistance to camptothecin (cpt) therapy was driven by degradation of DDX5. DDX5 knockdown decreased cell death and DNA damage and recovered cell proliferation in cpt treated 143B cells. Furthermore, we found that DDX5 bound to NONO, a kind of DNA repairing protein, and regulated NONO functions. Our data verified that cpt-induced degradation of DDX5 following by breaking down the protein bound of NONO, which participated in the resistance of cpt. In the summary, according to our results, DDX5 might be a potential therapeutic target for improving clinical outcomes of cpt in OS.
10.1016/j.yexcr.2020.112148
LINC01207 is up-regulated in gastric cancer tissues and promotes disease progression by regulating miR-671-5p/DDX5 axis.
Liu Hongquan,Liu Xiaoyu
Journal of biochemistry
LINC01207 is involved in the progression of some cancers. This study was designed to delve into the biological function and mechanism of LINC01207 in gastric cancer. Quantitative polymerase chain reaction (qPCR) was adopted to examine the expression levels of LINC01207, miR-671-5p, dead-box polypeptide 5 (DDX5) mRNA in gastric cancer tissues and cells. After LINC01207 was overexpressed or depleted, MTT and bromodeoxyuridine (BrdU) assays were conducted to detect cell proliferation. Transwell assay was employed to detect cell migration and invasion. Western blot was used to detect the expression of DDX5 protein in cells. Bioinformatics analysis, luciferase reporter assay and RNA pull-down assay were performed to predict and validate the binding site between miR-671-5p and LINC01207 or DDX5. LINC01207 and DDX5 mRNA were upregulated in gastric cancer, while miR-671-5p was downregulated; high expression of LINC01207 and transfection of miR-671-5p inhibitors facilitated the proliferation of gastric cancer cells; however, knocking down LINC01207 and the overexpression of miR-671-5p mimics had opposite biological effects. LINC01207 and miR-671-5p were interacted and miR-671-5p was negatively regulated by LINC01207. MiR-671-5p could reverse the function of LINC01207. DDX5 was a downstream target of miR-671-5p and was positively modulated by LINC01207. LINC01207 promotes the proliferation and metastasis of gastric cancer cells by regulating miR-671-5p/DDX5 axis.
10.1093/jb/mvab050
Knockdown of terminal differentiation induced ncRNA (TINCR) suppresses proliferation and invasion in hepatocellular carcinoma by targeting the miR-218-5p/DEAD-box helicase 5 (DDX5) axis.
Zhao Huibo,Xie Zhantao,Tang Gaofeng,Wei Sidong,Chen Guoyong
Journal of cellular physiology
Terminal differentiation induced ncRNA (TINCR), a newly identified lncRNA, has been found to be associated with different human cancers including hepatocellular carcinoma (HCC). However, little is known regarding the pathological mechanisms of TINCR in HCC progression. In this study, we confirmed that TINCR expression was upregulated in HCC tumors and cell lines, and high TINCR expression was associated with larger tumor size, advanced tumor node metastasis stage, and poor prognosis. Functionally, knockdown of TINCR facilitated apoptosis and suppressed viability, colony formation and invasion in Huh7 and Hep3B cells. Mechanically, TINCR functioned as competing endogenous RNA (ceRNA) to regulate DEAD-box helicase 5 (DDX5) expression through sponging miR-218-5p. Moreover, the miR-218-5p expression was downregulated and DDX5 expression was upregulated in HCC tumors. The silencing of miR-218-5p or ectopic expression of DDX5 abated the tumor-suppressive effect of TINCR knockdown in vitro. Furthermore, si-TINCR-induced inactivation of AKT signaling was rescued by suppression of miR-218-5p or overexpression of DDX5. Also, the silencing of TINCR resulted in tumor growth inhibition in vivo. In summary, knockdown of TINCR suppressed HCC progression presumably by inactivation of AKT signaling through targeting the miR-218-5p/DDX5 axis, suggesting a novel TINCR/miR-218-5p/DDX5 pathway and therapy target for HCC.
10.1002/jcp.29595
LncPSCA in the 8q24.3 risk locus drives gastric cancer through destabilizing DDX5.
EMBO reports
Genome-wide association studies (GWAS) have identified multiple gastric cancer risk loci and several protein-coding susceptibility genes. However, the role of long-noncoding RNAs (lncRNAs) transcribed from these risk loci in gastric cancer development and progression remains to be explored. Here, we functionally characterize a lncRNA, lncPSCA, as a novel tumor suppressor whose expression is fine-regulated by a gastric cancer risk-associated genetic variant. The rs2978980 T > G change in an intronic enhancer of lncPSCA interrupts binding of transcription factor RORA, which down-regulates lncPSCA expression in an allele-specific manner. LncPSCA interacts with DDX5 and promotes DDX5 degradation through ubiquitination. Increased expression of lncPSCA results in low levels of DDX5, less RNA polymerase II (Pol II) binding with DDX5 in the nucleus, thus activating transcription of multiple p53 signaling genes by Pol II. These findings highlight the importance of functionally annotating lncRNAs in GWAS risk loci and the great potential of modulating lncRNAs as innovative cancer therapy.
10.15252/embr.202152707
The lncRNA NEAT1 activates Wnt/β-catenin signaling and promotes colorectal cancer progression via interacting with DDX5.
Zhang Meng,Weng Weiwei,Zhang Qiongyan,Wu Yong,Ni Shujuan,Tan Cong,Xu Midie,Sun Hui,Liu Chenchen,Wei Ping,Du Xiang
Journal of hematology & oncology
BACKGROUND:The long noncoding RNA nuclear-enriched abundant transcript 1 (NEAT1) has been reported to be overexpressed in colorectal cancer (CRC). However, its underlying mechanisms in the progression of CRC have not been well studied. METHODS:To investigate the clinical significance of NEAT1, we analyzed its expression levels in a publicly available dataset and in 71 CRC samples from Fudan University Shanghai Cancer Center. Functional assays, including the CCK8, EdU, colony formation, wound healing, and Transwell assays, were used to determine the oncogenic role of NEAT1 in human CRC progression. Furthermore, RNA pull-down, mass spectrometry, RNA immunoprecipitation, and Dual-Luciferase Reporter Assays were used to determine the mechanism of NEAT1 in CRC progression. Animal experiments were used to determine the role of NEAT1 in CRC tumorigenicity and metastasis in vivo. RESULTS:NEAT1 expression was significantly upregulated in CRC tissues compared with its expression in normal tissues. Altered NEAT1 expression led to marked changes in proliferation, migration, and invasion of CRC cells both in vitro and in vivo. Mechanistically, we found that NEAT1 directly bound to the DDX5 protein, regulated its stability, and sequentially activated Wnt signaling. Our study showed that NEAT1 indirectly activated the Wnt/β-catenin signaling pathway via DDX5 and fulfilled its oncogenic functions in a DDX5-mediated manner. Clinically, concomitant NEAT1 and DDX5 protein levels negatively correlated with the overall survival and disease-free survival of CRC patients. CONCLUSIONS:Our findings indicated that NEAT1 activated Wnt signaling to promote colorectal cancer progression and metastasis. The NEAT1/DDX5/Wnt/β-catenin axis could be a potential therapeutic target of pharmacological strategies.
10.1186/s13045-018-0656-7
LncRNA PRADX-mediated recruitment of PRC2/DDX5 complex suppresses UBXN1 expression and activates NF-κB activity, promoting tumorigenesis.
Li Yansheng,Liu Xing,Cui Xiaoteng,Tan Yanli,Wang Qixue,Wang Yunfei,Xu Can,Fang Chuan,Kang Chunsheng
Theranostics
Accumulating evidence indicates that long noncoding RNAs (lncRNAs) play crucial roles in cancer progression; however, only few have been characterized in detail. The current study aimed to identify a novel cancer driver lncRNA in glioblastoma and colon adenocarcinoma. We performed whole transcriptome analysis of TCGA pan-cancer datasets to compare the lncRNA expression profiles of tumor and paired normal tissues. hybridization of tissue sections was performed to validate the expression data and determine the localization of lncRNAs that may be linked to glioblastoma and colon adenocarcinoma. Chromatin isolation by RNA purification (ChIRP), chromatin immunoprecipitation (ChIP), and Co-immunoprecipitation (Co-IP) assays were performed to assess the interaction between lncRNA, proteins, and chromatin. The functional significance of the identified lncRNAs was verified and by knockdown or exogenous expression experiments. We found a lncRNA ENST00000449248.1 termed PRC2 and DDX5 associated lncRNA (PRADX) that is highly expressed in glioblastoma and colon adenocarcinoma cells and tissues. PRADX, mainly located in the nucleus of tumor cells, could bind to EZH2 protein via the 5' terminal sequence. Moreover, PRADX increased the trimethylation of H3K27 in the UBXN1 gene promoter via PRC2/DDX5 complex recruitment and promoted NF-κB activity through UBXN1 suppression. Knockdown of PRADX significantly inhibited tumor cell viability and clonogenic growth . In xenograft models, PRADX knockdown suppressed tumor growth and tumorigenesis and prolonged the survival of tumor-bearing mice. PRADX acts as a cancer driver and may serve as a potential therapeutic target for glioblastoma and colon adenocarcinoma.
10.7150/thno.54549
Resveratrol directly targets DDX5 resulting in suppression of the mTORC1 pathway in prostate cancer.
Taniguchi T,Iizumi Y,Watanabe M,Masuda M,Morita M,Aono Y,Toriyama S,Oishi M,Goi W,Sakai T
Cell death & disease
Resveratrol has various attractive bioactivities, such as prevention of cancer, neurodegenerative disorders, and obesity-related diseases. Therefore, identifying its direct binding proteins is expected to discover druggable targets. Sirtuin 1 and phosphodiesterases have so far been found as the direct molecular targets of resveratrol. We herein identified 11 novel resveratrol-binding proteins, including the DEAD (Asp-Glu-Ala-Asp) box helicase 5 (DDX5, also known as p68), using resveratrol-immobilized beads. Treatment with resveratrol induced degradation of DDX5 in prostate cancer cells. Depletion of DDX5 caused apoptosis by inhibiting mammalian target of rapamycin complex 1 (mTORC1) signaling. Moreover, knockdown of DDX5 attenuated the inhibitory activities of resveratrol against mTORC1 signaling and cancer cell growth. These data show that resveratrol directly targets DDX5 and induces cancer cell death by inhibiting the mTORC1 pathway.
10.1038/cddis.2016.114
LncRNA CCAT1 Promotes Prostate Cancer Cell Proliferation by Interacting with DDX5 and MIR-28-5P.
You Zonghao,Liu Chunhui,Wang Can,Ling Zhixin,Wang Yiduo,Wang Yali,Zhang Minghao,Chen Shuqiu,Xu Bin,Guan Han,Chen Ming
Molecular cancer therapeutics
Accumulated evidence indicates that CCAT1 functions as an oncogene in the progression of a variety of tumors. However, little is known as to how CCAT1 impacts tumorigenesis in human prostate cancer. In this study, we found from The Cancer Genome Atlas and Memorial Sloan Kettering Cancer Center database that CCAT1 is highly upregulated in castration-resistant prostate cancer (CRPC) compared with androgen-dependent prostate cancer (ADPC). Higher level of CCAT1 leads to increased mortality in patients with CRPC. and studies show that CCAT1 promotes prostate cancer cell proliferation as well as the tumor growth of prostate cancer xenografts. Mechanistically, in cytoplasm, CCAT1 sponges MIR-28-5P to prevent the anticancer effect. In nucleus, CCAT1 acts as a scaffold for DDX5 (P68) and AR transcriptional complex to facilitate the expression of AR-regulated genes, thus stimulating CRPC progression. Our findings suggest that CCAT1 is an oncogenic factor in the progression of CRPC with different regulatory mechanisms in the nucleus and cytoplasm of cells.
10.1158/1535-7163.MCT-19-0095
LMTK3 escapes tumour suppressor miRNAs via sequestration of DDX5.
Cancer letters
Lemur tyrosine kinase-3 (LMTK3) plays an important role in cancer progression and is associated with breast, lung, gastric and colorectal cancer. MicroRNAs (miRNAs) are small endogenous non-coding RNAs that typically repress target genes at post-transcriptional level and have an important role in tumorigenesis. By performing a miRNA expression profile, we identified a subset of miRNAs modulated by LMTK3. We show that LMTK3 induces miR-34a, miR-196-a2 and miR-182 levels by interacting with DEAD-box RNA helicase p68 (DDX5). LMTK3 binds via DDX5 to the pri-miRNA of these three mature miRNAs, thereby sequestrating them from further processing. Ectopic expression of miR-34a and miR-182 in LMTK3-overexpressing cell lines (MCF7-LMTK3 and MDA-MB-231-LMTK3) inhibits breast cancer proliferation, invasion and migration. Interestingly, miR-34a and miR-182 directly bind to the 3'UTR of LMTK3 mRNA and consequently inhibit both its stability and translation, acting as tumour suppressor-like miRNAs. In aggregate, we show that LMTK3 is involved in miRNA biogenesis through modulation of the Microprocessor complex, inducing miRNAs that target LMTK3 itself.
10.1016/j.canlet.2015.12.026
Analysis of the RNA helicase p68 (Ddx5) as a transcriptional regulator.
Nicol Samantha M,Fuller-Pace Frances V
Methods in molecular biology (Clifton, N.J.)
The DEAD box RNA helicase p68 (Ddx5) has been demonstrated to act as a transcriptional co-activator for a number of highly regulated transcription factors (e.g. estrogen receptor alpha and the tumour suppressor p53) and to be recruited to promoters of genes that are responsive to activation of these transcription factors, suggesting that it may play a role in transcription initiation. We have investigated the function of p68 as a co-activator of the tumour suppressor p53, with a particular emphasis on the importance of p68 in the induction of p53 transcriptional activity by DNA damage. These studies have involved RNAi-mediated suppression of p68 in cells expressing wild-type p53 and determining its effect on the expression of cellular p53 target genes in response to DNA damage. Additionally a significant amount of our research has focused on the study of the role of p68 in transcriptional initiation; this has included an investigation of the recruitment of p68 to the promoters of p53-responsive genes and of the importance of p68 in influencing recruitment of p53. Here we present detailed methods for RNAi knock-down of p68 expression, determination of its effect on expression of p53-responsive genes by quantitative RT-PCR and Western blotting, and chromatin immunoprecipitation techniques for determining recruitment of p68 and p53 to p53-responsive promoters.
10.1007/978-1-60327-355-8_19
The DEAD box protein p68: a crucial regulator of AKT/FOXO3a signaling axis in oncogenesis.
Sarkar M,Khare V,Guturi K K N,Das N,Ghosh M K
Oncogene
Increased abundance of proto-oncogene AKT and reduced expression of tumor suppressor Forkhead box O3 (FOXO3a), the downstream target of AKT, is frequent in carcinogenesis. Mechanistic insights of AKT gene regulation are limited. DEAD box RNA helicase p68 is overexpressed in various cancers and acts as a transcriptional co-activator of several transcription factors, including β-catenin. Here, we report a novel mechanism of p68-mediated transcriptional activation of AKT, and its ensuing effect on FOXO3a, in colon carcinogenesis. Interestingly, we found that the expression of p68 and AKT exhibits strong positive correlation in normal and colon carcinoma patient samples. In addition, p68 increased both AKT messenger RNA (mRNA) and protein, enhanced AKT promoter activity in multiple colon cancer cell lines. Conversely, p68 knockdown led to reduced AKT mRNA and protein, diminished AKT promoter activity. Here, we demonstrated that p68 occupies AKT promoter with β-catenin as well as nuclear factor-κB (NF-κB)and cooperates with these in potentiating AKT transcription. Furthermore, p68 and FOXO3a expression followed inverse correlation in the same set of colon carcinoma samples. We observed that p68 significantly reduced FOXO3a protein level in an AKT-dependent manner. Studies in primary tumors and metastatic lung nodules generated in mice colorectal allograft model, using syngeneic cells stably expressing p68, corroborated our in vitro findings. Hence, a new mechanism of oncogenesis is attributed to p68 by upregulation of AKT and consequent nuclear exclusion and degradation of tumor suppressor FOXO3a.
10.1038/onc.2015.42