关键词: X 线, 神经胶质瘤, P27^kip1<, sup>, 细胞周期

Abstract: To investigate the effects of pEgr-hPTEN stable transfer combined with irradiation on the cell cycle progression and the expression of cell cycle kinase inhibitor P27^kip1 protein of SHG-44 human glioma cells. Methods pEgr-hPTEN vector containing the exogenous wild type PTEN gene was transfected into SHG-44 cells under mediation of lipofectamine in vitro, the positive cell clones were selected and amplified by using G418.Western blotting was used to measure the expression of PTEN protein. Transmission electron microscope was adopted to detect the cell ultrastructural changes and flow cytometry was adopted to analysis the changes of cell cycle progression and the expression of P27^kip1 in SHG-44- sPTEN cells followed by different doses of X-ray irradiation. Results Egr-1 promoter could be induced and activated by irradiation and then enhanced the expression of downstream PTEN gene within 5Gy. The ultrastructure of SHG-44- sPTEN cells had many degenerative changes and many early apoptotic changes including the chromosome condensate around the nuclear envelope. pEgr-hPTEN stable transfer combined with X-ray irradiation could significantly induce G₁ arrest. The expression of P27^kip1 proteins increased in SHG-44-sPTEN stable transfected cells. Conclusion PTEN stable transfer combined with irradiation can significantly induce G₁ arrest. The molecular basis may be correlated with the enhanced expression of PTEN induced by irradiation and increased expression of cell cycle kinase inhibitor P27^kip1.

Key words: X-rays, glioma, P27^kip1<, sup>, cell cycle