HIF-1alpha restricts proliferation and apoptosis of Tca8113 cells through up regulation of Hippo signaling pathway under hypoxic conditions.

OBJECTIVE: The hypoxia-inducible factor-1alpha (HIF-1alpha) is a key factor for tumor cells adaptation to hypoxia. Studies have shown that under hypoxic conditions, HIF-1alpha expression was significantly increased in human tongue squamous cell carcinoma cells (Tca8113). This research aims to determine the exact mechanism of HIF-1alpha on the proliferation and apoptosis of Tca8113 cells. MATERIALS AND METHODS: Tca8113 cells were cultured under normoxia and hypoxia. Real Time-PCR and Western blot were used to measure the expression levels of HIF-1alpha and TAZ. Under hypoxic condition, HIF-1alpha siRNA was transfected into Tca8113 cells. CCK8 was used to measure the proliferation of Tca8113 cells. Flow cytometry was used to detect apoptosis of Tca8113 cells. RESULTS: Under hypoxic condition, the expression levels of HIF-1alpha and TAZ at both mRNA and protein levels were significantly increased (p <0.05). The downregulation of HIF-1alpha by siRNA significantly inhibited Tca8113 cells proliferation, increased their apoptosis, and reduced the expression level of TAZ. CONCLUSIONS: Under hypoxic conditions, HIF-1alpha inhibits the proliferation and apoptosis of Tca8113 cells via the elevation of the Hippo signaling pathway.