Effect of Hypoxia on the Expression of Hypoxia Inducible Factor 1α、p53 、bcl-2 and Apoptosis in Osteosarcoma Cell Line MG-63

Objective 　To investigate the effect of hypoxia on the expression of ypoxia inducible factor 1α (HIF-1α) 、p53 、bcl-2 and apoptosis in osteosarcoma cell line MG263 under hypoxia environment . Methods The hypoxia culture model was established by a hypoxia incubator. The gene productions of HIF-1α、p53 、bcl-2 and the changes of the apoptosis were observed at different hypoxia culture phase. The semi-quantitative reverse t ranscriotion PCR(RT-PCR) was used to test the mRNA expression of HIF-1α、p53 and bcl-2. The protein level of HIF-1α、p53 and bcl-2 was observed by immunohistochemical staining and western blot analysis. The changes of apoptosis were analyzed using flow cytometry. Results 　After the hypoxia treatment, the mRNA level of HIF-1αwas not changed significantly, however, the protein expression of HIF-1αwas increased remarkably with correspondence to the hypoxia time. But the expression of p53 and bcl-2 were up-regulated in mRNA and protein level .Besides, the bcl-2 activity was markedly associated with the level of HIF-1α. However, the apoptosis rate was not increased markedly. Conclusion 　In hypoxia environment, the apoptosis of osteosarcoma cell line MG-63 could not induce by the p53 avenue which depended on HIF-1α. The mechanism is possibly related with the mutation of p53 that increases the expression of HIF-1αand bcl-2.