pEgr-hPTEN稳定转染联合辐射诱导人胶质瘤SHG-44细胞凋亡及Bcl-2表达下调

目的 探讨辐射诱导表达载体pEgr-hPTEN体外稳定转染人胶质瘤SHG-44细胞后联合X射线照射，诱导细胞凋亡的作用及凋亡相关蛋白Bcl-2表达的变化。方法 以脂质体介导携有外源野生型PTEN基因的辐射诱导表达载体pEgr-hPTEN，体外转染SHG-44细胞，筛选稳定转染的细胞克隆并扩增培养；应用电子显微镜、流式细胞仪等方法，检测稳定转染联合X射线照射对胶质瘤细胞超微结构、细胞凋亡及Bcl-2蛋白表达等特性的影响。结果 稳定转染细胞超微结构有明显的退行性改变，可见核内染色质趋边的类似早期凋亡的改变；稳定转染联合X射线照射可诱导肿瘤细胞凋亡，5Gy以内随吸收剂量的增加，早期凋亡细胞百分数明显增加，稳定转染不同剂量照射组早期凋亡细胞百分数分别为稳定转染0Gy假照组的1．5—2．3倍、为未转染照射组的1．9—4．4倍、为未转染0Gy假照组的3．4—5．1倍；同时稳定转染细胞Bcl-2蛋白表达则呈剂量依赖性下降。结论 体外PTEN基因转染联合X射线照射可诱导肿瘤细胞凋亡明显增多，Bcl-2蛋白表达下调，具有显著的肿瘤抑制作用。

Apoptosis and down-reguled expression of Bcl-2 in SHG-44 glioma cells induced by pEgr-hPTEN stable transfection in combination with X-ray irradiation

Objective To investigate the apoptotie effect and the changes of Bcl-2 protein expression of pEgr-hPTEN stable transfection in SHG-44 human glioma cells in combination with irradiation. Methods pEgr- hPTEN vector containing the exogenous wild type PTEN gene was transfected into SHG-44 cells under mediation of lipefectamine in vitro ; the positive cell clones called SHG-44-hPTEN were selected and amplified by using G418. Transmission electron-microscope was used to detect the cell ultrastruetural changes and flow cytometry to measure the apeptotic effect and Bcl-2 expression of SHG-44- hPTEN cells after X-ray irradiation at different doses. Results Many degenerative changes and early apeptotic changes including the chromosome condensate around the nuclear envelope were observed in SHG-44- hPTEN cells, pEgr-hPTEN stable transfection in combination with X-ray irradiation can significantly induce the apeptosis of SHG-44 cells. The percentage of early apeptosis is of SHG-44-hPTEN cells irradiated with X-rays at different doses was 1.5-2.3 times as much as that of SHG-44-hPTEN/0 Gy group, 1.9-4.4 times as much as that of SHG-44 irradiated group, and 3.4-5.1 times as much as that of SHG-44/0 Gy group. The expression of Bcl-2 proteins decreased in dose-dependent manner. Conclusion PTEN stable transfection in combination with irradiation can significantly induce the apeptosis of tumor cells and significantly down-regulate the expression of Bcl-2 protein.