Role of hypoxia-inducible-1α in hepatocellular carcinoma cells using a Tet-on inducible system to regulate its expression in vitro.

Hypoxia-inducible-1α (HIF-1α) expression was intimately correlated with apoptosis and proliferation of cancer cells. However, conclusions of different studies on the effects of HIF-1α expression on cell apoptosis and cell proliferation of hepatoma cells remain controversial. In view of the current status, we reassess its roles and possible mechanism in hepatoma cells. In order to acquire more convincing and reliable results, we used a Tet-on system to stably and effectively regulate HIF-1α expression in the HepG2 cells in vitro. In our study we not only confirmed some common conclusions of previous studies, but also acquired some different and significant results that HIF-1α facilitates cell proliferation and cell cycle through influencing the expression of cyclin A and cyclin D, and suppresses cell apoptosis through inducing the expression of survivin and Bcl-2. These results further enrich our knowledge on the role of HIF-1α expression on cell apoptosis and cell proliferation of hepatoma cells.