MicroRNA-199a-3p inhibits tumorigenesis of hepatocellular carcinoma cells by targeting ZHX1/PUMA signal

Background and objective: MicroRNAs play an important role in cell proliferation, apoptosis, differentiation, and invasion by regulating the expression of various genes. For example, the downregulation of microRNA-199a-3p (miR-199a-3p) that is noted in numerous human malignancies, including hepatocellular carcinoma (HCC), results in a poor prognosis in patients with HCC. This finding suggests that miR-199a-3p overexpression in HCC could provide a new treatment approach. We explored this possibility by examining the effects of miR-199a-3p on the growth and apoptosis of HCC cells in vitro and vivo.

Methods: The miR-199a-3p signaling pathway was examined using ZHX1 (zinc-fingers and homeoboxes-1) or PUMA (a p53 upregulated modulator of apoptosis) siRNA transfection to determine the effects of miR-199a-3p on growth and apoptosis of HepG2 cells in vitro. A subcutaneously implanted tumor model of HepG2 cells in nude mice was used to assess the effects of miR-199a-3p on the signaling pathway and tumorigenesis development in vivo.

Results: miR-199a-3p inhibited growth and induced apoptosis of HepG2 cells in vitro. These effects were accompanied by upregulation of ZHX1 and PUMA. Targeting ZHX1 inhibited upregulation of PUMA after miR-199a-3p transfection. In addition, miR-199a-3p inhibited Bcl2 expression, but increased Bax and cleaved caspase-3 expression. Targeting PUMA or ZHX1 reversed the effect of miR-199a-3p, followed by upregulation of Bcl2 and downregulation of Bax and cleaved caspase-3, respectively. Furthermore, miR-199a-3p inhibited tumorigenesis of xenografts in nude mice.

Conclusions: miRNA-199a-3p could effectively prevent primary tumor formation. The ability of this therapy to decrease tumorigenesis may be related toZHX1-dependent PUMA signals.