OncoTargets and Therapy (Oct 2020)
miR-135b-5p Suppresses Androgen Receptor-Enhanced Hepatocellular Carcinoma Cell Proliferation via Regulating the HIF-2α/c-Myc/P27 Signals in vitro
Abstract
Shi-xiang Bao,1,* Chun-hua Wang,2,* Shuai Jin,1 Kong-wang Hu,2 Jing-tao Lu1,3 1School of Life Sciences, Anhui Medical University, Hefei 230032, People’s Republic of China; 2Departments of General Surgery, The First Affiliated Hospital, Anhui Medical University, Hefei 230032, People’s Republic of China; 3George Whipple Laboratory for Cancer Research, Departments of Pathology and Urology and the Wilmot Cancer Center, University of Rochester Medical Center, Rochester, NY 14642, USA*These authors contributed equally to this workCorrespondence: Jing-tao Lu; Kong-wang HuAnhui Medical University, 81 Meishan Road, Shushan District, Hefei 230032, People’s Republic of ChinaTel/Fax +86 551 65160393Email [email protected]; [email protected]: Hepatocellular carcinoma (HCC) accounts for more than 90% of liver cancers and is ranked as the fifth most common malignancy. Androgen receptor (AR) may promote the progression of HCC at an early stage of the disease. However, this study identified miR-135b-5p as an AR upstream regulator can suppress AR protein expression and inhibit HCC proliferation, consistent with the idea that AR expression is negatively correlated with HCC progression.Methods: The target microRNAs were predicted using online databases (TargetScan, miRDB, and MicroCosm Targets). Cell proliferation ability was measured by MTT and colony formation assay. Western blot was performed to analyze the expression levels of AR, HIF-2α, c-Myc, and p27, which are related to HCC proliferation. Chromatin immunoprecipitation (ChIP) assay and luciferase reporter assay were carried out to investigate the mechanism by which miR-135b-5p decreases AR expression.Results: miR-135b-5p suppresses HCC cell proliferation and AR expression. Downregulation of AR expression by miR-135b-5p may in turn transcriptionally modulate HIF-2α expression via direct binding of AR to the androgen response element (ARE) in the HIF-2α promoter. Further dissection of the mechanism revealed that AR-modulated HIF-2α could suppress c-Myc expression resulting in increased p27 expression that likely contributes to the suppression of proliferation in HCC cells.Conclusion: miR-135b-5p suppresses HCC cell proliferation via targeting AR-modulated HIF-2α/c-Myc/p27 signals, which may help to develop more effective therapies to prevent HCC progression.Keywords: HCC, miR-135b-5p, AR, HIF-2α, c-Myc, p27
