Apoptosis Induction in Glioma Cells by Downregulation of HIF-1α Gene

HIF-1 transcription factor is a key determinant of oxygen-dependent gene regulation, which its role has been demonstrated for the survival and progress of cancer tumors. The effect of suppression of HIF-1α on the evaluation of HIF-1 dependent processes and interference with pathophysiological events caused by hypoxia is important. The aim of this study was the apoptosis induction in glioma cells by downregulation of Hif-1α gene. In this experimental study, a specific siRNA against the HIF1α gene was developed using OligoWalk and Mit (siRNA.wi.mit.edu) servers and the online design department of Invivogene and Qiagene companies and the efficacy of its silencing in the U87 glioma cell line was quantitatively investigated by the Real-time PCR technique. In order to find out the effect of reduction of expression in the process of cell cycle and apoptosis, staining with PI and Annexin-PI was performed and the number of cells in each phase and the rate of cell mortality with control were compared by flow cytometry. The designed HIF-1a-siRNA was able to reduce HIF1α expression by 40%. The treatment of U87 cells after 24 hours increased the cells by 6% and after 48 hours, increased them by 12% in the sub G1 stage. Confirming the cell cycle changes, 48-hour treatment induced apoptosis in 58% of cells; regarding the 1.5% rate of apoptosis in the control cells, this cell death rate was very significant and showed the ability of the designed siRNA to induce apoptosis. The apoptosis induction of specific siRNA designed against HIF1α gene has a significant effect on the reduction of HIF-1α gene expression, cell growth, and apoptosis.