The impact of hypoxia inducible factor 1α antisense oligonucleotides on the expression of hypoxia inducible factor 1α、P53、Bcl-2 and apoptosis in osteosarcoma cell line MG-63

Background and purpose:To investigate the effect of hypoxia inducible factor 1α(HIF-1α) antisense oligonucleotides(ASODN) on the expression of HIF-1α、P53、Bcl-2 and apoptosis in osteosarcoma cell line MG-63 under hypoxia environment, and to explore the mechanism of HIF-1α on apoptosis induced by hypoxia in tumor cell. Methods:The ASODN and sense oligodeoxynucleotides(SODN) were designed on the basis of the HIF-1α cDNA sequence.The hypoxia culture model was established by a hypoxia incubator. The gene productions of HIF-1α、P53 and Bcl-2 were observed at different hypoxia culture phase. The semi-quantitative reverse transcriotion PCR(RT-PCR) was used to test the mRNA expression of HIF-1α、P53 and Bcl-2.The protein levels of HIF-1α、P53 and Bcl-2 were observed by immunohistochemical staining and Western Blot analysis. The induction of apoptosis were analyzed using flow cytometryResults:Compared with cells under aerobic situation, the mRNA level of HIF-1α was not significantly changed for the cells under hypoxic environment, however, the protein expression of HIF-1α was remarkably increased with correspondence to the time of the cells exposure to both pure hypoxia and the SODN hypoxia. The expression of P53 and Bcl-2 were up-regulated in terms of mRNA and protein levels. The apoptotic rate was not markedly increased. After treated with the ASODN, the cellular mRNA and protein levels of HIF-1α、P53 and Bcl-2 were evidently decreased and the apoptotic rate was significantly increased .Conclusions:The expression of HIF-1α and Bcl-2 are upregulated through induction of wild type P53 to mutation under hypoxia environment, which would inhibit the apoptosis of tumour cell. However, the ASODN could reduce the P53 mutation and the Bcl-2 expression by inhibiting the activity of the HIF-1α,which would salvage the cells from apoptosis.