MicroRNA-363-3p/p21(Cip1/Waf1) axis is regulated by HIF-2α in mediating stemness of melanoma cells

Abstract

Melanoma is a malignant tumor. The acquisition of stemness by melanoma cells aggravates the malignant transformation, which can be regulated by microRNAs (miRNAs, miR). MiR-363-3p is a key tumor-related miRNA, but its role in stemness and melanoma cells is still unknown. Presently, miR-363-3p induced by hypoxia inducible factor (HIF)-2α has a positive role in melanoma cell stemness. The levels of miR-363-3p and HIF-2α are upregulated in melanoma cell lines. Overexpression of HIF-2α significantly increased levels of miR-363-3p. However, both HIF-2α knockdown and miR-363-3p inhibition decreased the levels of stemness markers (CD133, CD271, Jarid1B and Nanog). Furthermore, the levels of miR-363-3p and HIF-2α were upregulated in fluorescence activated cell sorting (FACS)-sorted CD271high/+ cells. Whereas, miR-363-3p depletion reduced the proportion and the ability of the CD271high/+ cells to form spheroids, decreased the levels of CD133, CD271, Jarid1B and Nanog with restrained proliferative activity of CD271high/+ cells. Additionally, miR-363-3p was confirmed a key downstream effector of HIF-2α. Intriguingly, cyclin-dependent kinase inhibitor 1A [CDKN1A, p21(Cip1/Waf1)], a key inhibitor of S-phase DNA synthesis and cell cycle progression, was confirmed a target gene of miR-363-3p by luciferase reporter gene assay. The protein levels of CD133, CD271, Jarid1B and Nanog were upregulated with enhanced proliferative activity of CD271high/+ cells by inhibition of p21 in melanoma cells. In conclusion, miR-363-3p is induced by HIF-2α to promote stemness of melanoma cells via inhibiting p21. The present study provides novel insights and indicates that HIF-2α/miR-363-3p/p21 signaling may be a potential target in melanoma research and therapy.