Silencing Hypoxia-inducible Factor-1α gene Transcription on Effects of Human hepG2 cell Proliferation and Angiogenesis Factors

Hypoxia-inducible factor (HIF)-1 alpha is a key transcription regulator for multiple angiogenic factors and appealing target and HIF-1 alpha promotes angiogenesis are not fully understood. Therefore, we investigated the effects of silencing HIF-1 alpha on proliferation of HepG2 cells and angiogenesis. After the cells transfected with HIF-1 alpha miRNA at 72 h, HIF-1 alpha expression was down to 23 % at mRNA level by quantitative real time PCR and 44 % at protein level by Western blotting. The expressions of the down-stream vascular endothelial growth factor and angiopoietin-2 were decreased 54 % and 34 % by enzyme-linked immunosorbent assay, respectively. The alteration of cell cycle proportion was 61.49 % in G1 phase, 22.40 % in S phase, and not in G2/M phase. The apoptotic ratio of HepG2 cells increased from 22.46 % to 36.99 % with 65.68 % of G1 phase and 19.47 % of S phase when HIF-1 alpha activation interfering with miRNA plus doxorubicin by flow cytometry or annexin Annexin-V-FLUOS assay. The down-regulated HIF-1 alpha expression resulted in decreasing angiogenic factors, inhibition of HepG2 cell growth, and inducing apoptosis. Therefore, we conclude that HIF-1 alpha may serve as a useful molecular target for miRNA-based liver cancer therapy.