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

用DXR与GSH通过戊二醛的合成缀合物（GSH-DXR）处理细胞，导致细胞色素c在通过典型的DNA片段化有效激活半胱天冬酶-3和-9后从线粒体释放到细胞质。这种凋亡是由JNK信号通路调节的。在本实验中，用GSH-DXR处理细胞引起Bcl-xL的脱酰胺，其位于线粒体膜中。Bcl-xL的脱酰胺作用使其抗凋亡作用消失，并促进线粒体细胞色素c的释放。此外，GSH-DXR诱导的JNK激活引起Bax从胞质移位到线粒体，并且还促进细胞色素c的释放。Bax在胞浆中与胞浆蛋白形成50-60 kDa的复合物，并通过GSH-DXR诱导的JNK激活而被转运到线粒体中。GST-P过表达可抑制JNK的激活，并降低Bcl-xL脱酰胺和Bax转位。这些结果提示Bcl-2家族如Bcl-xL和Bax作为JNK的靶分子参与了JNK诱导细胞凋亡的作用。此外，病灶/结节在5 - 6周时增加，此后形成结节。病灶/结节中GST-P水平在5周时显著升高，此后逐渐下降。而JNK在各期的表达水平无明显变化。提示GST-P对JNK活性的抑制作用随病灶/结节的形成而增强，从而加速了肿瘤的恶变。

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.