EZH2-mediated Pathways Promote Tumor Progression In Prostate Cancer And Bladder Cancer

Attenuation of TGFBR2 Expression and Tumour Progression in Prostate Cancer Involve Diverse Hypoxia-Regulated EZH2-associated PathwayBackground:Dysregulation of transforming growth factor ?(TGF-?)signaling and hypoxic microenvironment have respectively been reported to be involved in disease progression in malignancies of prostate.Emerging evidence indicates that downregulation of TGFBR2,a pivotal regulator of TGF-? signaling,may contribute to carcinogenesis and progression of prostate cancer(PCa).However,the biological function and regulatory mechanism of TGFBR2 in PCa remain poorly understood.In this study,we propose to investigate the crosstalk of hypoxia and TGF-? signaling and provide insight into the molecular mechanism underlying the regulatory pathways in PCaMethods:Prostate cancer cell lines were cultured in hypoxia or normoxia to evaluate the effect of hypoxia on TGFBR2 expression.Methylation specific polymerase chain reaction(MSP)and demethylation agents was used to evaluate the methylation regulation of TGFBR2 promoter.Besides,silencing of EZH2 via specific siRNAs or chemical inhibitor was used to validate the regulatory effect of EZH2 on TGFBR2.Moreover,we conducted PCR,western blot,and luciferase assays which studied the relationship of miR-93 and TGFBR2 in PCa cell lines and specimens.We also detected the impacts of hypoxia on EZH2 and miR-93,and further examined the tumorigenic functions of miR-93 on proliferation and epithelial-mesenchymal transition via a series of experimentsResults:TGFBR2 expression was attenuated under hypoxia.Hypoxia-induced EZH2 promoted H3K27me3 which caused TGFBR2 promoter hypermethylation and contributed to its epigenetic silencing in PCa.Besides,miR-93 was significantly upregulated in PCa tissues and cell lines,and negatively correlated with the expression of TGFBR2.Ectopic expression of miR-93 promoted cell proliferation,migration and invasion in PCa,and its expression could also be induced by hypoxia.In addition,TGFBR2 was identified as a bona fide target of miR-93Conclusions:Our findings elucidate diverse hypoxia-regulated pathways including EZH2-mediated hypermethylation and miR-93-induced silencing contribute to attenuation of TGFBR2 expression and promote cancer progression in prostate cancerLncRNA-TUGl promotes cell growth and chemo-resistance by regulating CCND2 via epigenetically silencing of miR-194-5p in bladder cancerObjectives:Taurine upregulated 1(TUG1)has been involved in tumorigenesis of several human cancers,but its precise biological role in bladder cancer remains largely elusiveMaterials and Methods:Quantitative real-time PCR and western blot were utilized to evaluate the mRNA and protein expression level,respectively.Methylation specific PCR was conducted to determine the promoter methylation status.The miRNA and target mRNA binding was validated with dual luciferase reporter assay.In addition,MTS assay/colony formation,flow cytometry,animal experiment were used for evaluating the treatment on cell proliferation,apoptosis,and tumor growthResults:TUG1 was upregulated in bladder cancer and the expression of TUG1 was positively and negatively correlated with CCND2 and miR-194-5p,respectively.MiR-194-5p expression was frequently decreased through promoter hypermethylation while it was epigenetically increased following cisplatin and 5-Aza-DC treatment.Furthermore,knockdown of TUG1 attenuated the expression of epigenetic regulator EZH2,alleviated the promoter hypermethylation of miR-194-5p and induced its expression.Increased miR-194-5p expression or decreased TUG1 expression significantly sensitized bladder cancer cells to cisplatin,inhibited the proliferation,and induced apoptosis.Besides,CCND2 was a direct target of miR-194-5p,while miR-194-5p was regulated by TUG1.CCND2 could partially restore the tumor suppressive effects on cell proliferation and cisplatin resistance following TUG1 silencing.Additionally,TUG1 expression was correlated with clinical stage,lymphatic metastasis,and patient prognosis.Conclusions:TUG1 promotes bladder cancer cell growth and chemoresistance by regulating CCND2 via EZH2-associated silencing of miR-194-5p.Our study may be conducive to elucidate the molecular mechanism and provide novel therapeutic target and biomarker for bladder cancer.