Hsa-miR-637 inhibits human hepatocyte proliferation by targeting Med1-interacting proteins

Background:Recent studies have shown that mediator complex subunit 1(Med1)can significantly affect hepatocyte proliferation and differentiation.Acting as a tumor suppressor,microRNA-637(hsa-miR-637)can inhibit the growth of hepatocarcinoma cells and further induce cell apoptosis.However,the function of hsa-miR-637 and its target genes during liver regeneration remains to be elucidated.Methods:This study used co-immunoprecipitation(Co-IP)assay,transfection,luciferase reporter assay,functional assay by cell counting kit-8(CCK-8),Annexin V-FITC/propidium iodide apoptosis assay,and quantitative polymerase chain reaction analysis of chromatin immunoprecipitation(ChIP)for analysis.Results:Hsa-miR-637 has been suggested to suppress the expression of two Med1-interacting nuclear receptors,identified as the peroxisome proliferator-activated receptor alpha(PPARA)and thyroid hormone receptor alpha(THRA)at the transcriptional and translational levels in the human liver HL-7702 cell line.The interaction between Med1 and PPARA/THRA in HL-7702 cells was then confirmed.The transcriptional repression of hsa-miR-637 on PPARA and THRA was also demonstrated.Moreover,hsamiR-637 has been determined to suppress the proliferation of HL-7702 cells.Furthermore,cell cycle arrest of HL-7702 cells was induced by transfection of hsa-miR-637 at the S phase,but its apoptosis failed.Finally,PPARA was indicated to directly bind to the promoter of some transcription factors,like bcatenin,mouse double minute 2(MDM2),and p53.Conclusions:This study has confirmed that hsa-miR-637 plays an antiproliferative role during liver regeneration,which may contribute in understanding the regenerative process of the liver.