肿瘤抑制剂GA对SH-SY5Y细胞凋亡的影响及分子机制研究

Effects of GA on apoptosis of SH-SY5Y cells and its molecular mechanisms

为了探讨HSP90特异的功能抑制剂geldanamycin(GA)能否用于神经母细胞瘤的临床治疗 ,通过检测未分化的和全反式维甲酸 (RA)诱导分化的神经母细胞瘤SH SY5Y细胞在不同浓度GA处理后的细胞存活率 ,发现GA呈剂量依赖性诱导SH SY5Y细胞凋亡 ,但是分化细胞对同样剂量的GA不是很敏感 [细胞存活率依次为 (82 0±6 0 ) %比较 (6 5 0± 3 0 ) % ,P <0 0 2 ;(6 7 9± 3 1) %比较 (4 3 4± 3 9) % ,P <0 0 3;(4 3± 0 8) %比较 (0 4±0 1) % ,P <0 0 5 ]。Western印迹分析和免疫荧光实验显示 ,GA能抑制细胞中c Jun和c Fos的表达 ,并且GA剂量越高 ,其抑制越明显 ;同时GA也诱导了p5 3的核聚集。与未分化细胞相比 ,在相同剂量GA处理后分化细胞中c Jun和c Fos的表达均比未分化细胞略高 ;但是分化细胞中p5 3的核聚集却不如前者明显。提示未分化细胞对同样剂量的GA比分化细胞更敏感 ,可能与分化细胞能抵抗GA引起的c Jun、c Fos的降低以及p5 3的核聚集有关。

In order to investigate whether geldanamycin(GA), a specific inhibitor for Hsp90 function, can be clinically used to treat neuroblastomas, cell viability of undifferentiated and RA-induced differentiated SH-SY5Y under different concentrations of GA was detected. We found that GA induced apoptosis of SH-SY5Y in a dose-dependent manner, while the differentiated cells are more resistant to GA than the undifferentiated counterpart in the same concentration of GA [cell viability was as follow in turn: (82.0±6.0)% compare with (65.0±3.0)%, P<0.02; (67.9±3.1)% compare with (43.4±3.9)%, P<0.03; (4.3±0.8)% compare with (0.4±0.1)%, P< 0.05]. Western blot and immunofluorescence analyses showed that GA impaired the expression of both c-Jun and c-Fos while induced nuclear accumulation of p53. As comparing with SH-SY5Y cells, differentiated cells expressed slightly higher level of c-Jun and c-Fos in control condition and in the same concentration of GA treatment as well. However, the nuclear accumulation of p53 was not evident in differentiated cells. These results suggest that the inefficient repression of c-Jun and c-Fos and/or lower level of nuclear accumulation of p53 in the differentiated cells may confer higher resistance to GA induced apoptosis.