MiR-186, miR-216b, miR-337-3p, and miR-760 cooperatively induce cellular senescence by targeting α subunit of protein kinase CKII in human colorectal cancer cells.

We previously demonstrated that downregulation of protein kinase CKII induces cellular senescence in human colon cancer HCT116 cells. To investigate the role of microRNAs (miRNAs) in CKII downregulation during senescence, we employed computational algorithms. Four miRNAs (miR-186, miR-216b, miR-337-3p, and miR-760) were predicted to be miRNAs against CKIIα mRNA. Mimics of all four miRNAs jointly downregulated CKIIα expression in HCT116 cells. Reporter analysis and RT-PCR have suggested that these four miRNAs may stimulate degradation of CKIIα mRNA by targeting its 3' untranslated regions (UTRs). The four miRNA mimics increased senescent-associated β-galactosidase (SA-β-gal) staining, p53 and p21(Cip1/WAF1) expression, and reactive oxygen species (ROS) production. In contrast, concomitant knockdown of the four miRNAs by antisense inhibitors increased the CKIIα protein level and suppressed CKII inhibition-mediated senescence. Finally, CKIIα overexpression antagonized senescence induced by the four miRNA mimics. Therefore, the present results show that miR-186, miR-216b, miR-337-3p, and miR-760 cooperatively promote cellular senescence through the p53-p21(Cip1/WAF1) pathway by CKII downregulation-mediated ROS production in HCT116 cells.