Mechanism of apoptotic induction by targeting of GST P and its targeting therapy

通过戊二醛（GSH-DXR）将DXR与GSH合成偶联物（GSH-DXR）处理细胞，在典型的DNA片段激活caspase-3和-9后，细胞色素c从线粒体释放到细胞质中。这种凋亡受jnk信号通路的调控。在本实验中，用GSH-DXR处理细胞引起Bcl-xL脱酰胺，Bcl-xL定位于线粒体膜。脱酰胺使Bcl-xL的抗凋亡功能消失，促进线粒体细胞色素c的释放。此外，gsh - dxr诱导的JNK激活导致Bax从细胞质转移到线粒体，并促进细胞色素c的释放。在细胞质中，Bax定位为50-60 kDa的Bax复合物，与胞质蛋白结合，通过gsh - dxr诱导的JNK激活，解离的25 kDa Bax被转移到线粒体。GST-P过表达抑制JNK活化，降低Bcl-xL脱酰胺和Bax易位。这些结果提示Bcl-2家族如Bcl-xL和Bax作为JNK的靶分子起诱导凋亡的作用。大鼠腹腔注射二甲基亚硝胺，注射后2 ~ 3周观察到肝脏小灶的形成。5 ~ 6周灶/结节增多，随后形成结节。病灶/结节GST-P水平在5周时急剧升高，随后逐渐下降。各阶段JNK表达水平均无变化。提示GST-P对JNK活性的抑制随着灶/结节的形成而增加，从而加速了恶性改变。

Treatment of cells with a synthetic conjugate of DXR with GSH via glutaraldehyde (GSH-DXR) caused cytochrome c release from the mitochondria to the cytosol following potent activation of caspase-3 and -9 by typical DNA fragmentation. This apoptosis was regulated by the JNK-signaling pathway. In the present experiment, treatment of cells with GSH-DXR caused deamidation of Bcl-xL, which is localized in mitochondrial membrane. The deamidation of Bcl-xL was disappeared anti-apoptotic function and facilitated the release of cytochrome c from mitochondria. Moreover, GSH-DXR-induced JNK activation caused Bax translocation from cytosol to mitochondria, and also facilitated the release of cytochrome c. Bax was localized as 50-60 kDa Bax-complex with cytosolic protein in cytosol, and dissociated 25 kDa Bax was translocated to mitochondria by GSH-DXR-induced JNK activation. Overexpression of GST-P was suppressed JNK activation and decreased in both Bcl-xL deamidation and Bax translocation. These result were suggested that Bcl-2 family such as Bcl-xL and Bax, acted the induction of apoptosis as target molecule of JNK.When dimethylnitrosamine was injected intraperitoneally to rat, the formation of mini-foci in the liver was observed at two to three weeks after injection. Moreover, foci/nodule was increased at five to six weeks and nodule was formed thereafter. GST-P levels in Foci/nodule was increased extremely at five weeks and decreased gradually thereafter. However, no change in the level of JNK expression in each stage. It was suggested that suppression of JNK activity by GST-P increase in accordance with the formation of Foci/nodule caused to accelerate malignant alteration.