Attenuation of both apoptotic and necrotic actions of cadmium by Bcl-2.
Attenuation of both apoptotic and necrotic actions of cadmium by Bcl-2.
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DOI：
10.1289/ehp.0211037
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发表时间：
2002-01
影响因子：
10.4
通讯作者：
Kunimoto, Manabu
中科院分区：
文献类型：
--
作者：
Ishido, Masami;Ohtsubo, Rieko;Adachi, Tatsumi;Kunimoto, Manabu
我们研究了镉对bcl-2家族蛋白--bcl-2、bax、bad和bcl-xS/L--在镉诱导的细胞毒性中的影响。向培养的猪肾LLC-PK（1）细胞中加入10 μ M镉可引起细胞凋亡。Western印迹分析表明，镉显着增加内源性bcl-2蛋白（3 - 4倍的野生型细胞中的水平）早于金属硫蛋白诱导，但金属没有增强诱导的bax，坏，或bcl-xS蛋白。镉还诱导bcl-2的转录，bcl-2的量在暴露1 - 2小时达到最大值;这种增加早于镉诱导的原癌基因如c-myc的增加。镉诱导的内源性bcl-2蛋白的增加，也被认为是在大鼠原代胸腺细胞。通过基因转染过表达bcl-2蛋白阻止镉诱导的细胞凋亡。在检测到细胞凋亡后，观察到培养基中乳酸脱氢酶的释放（坏死的标志物），并且这种释放也被bcl-2的过表达抑制。电子显微镜观察也支持这样的事实，即镉诱导凋亡染色质凝聚在曝光的早期阶段，其次是细胞的坏死特征，这两者也被抑制过表达的bcl-2蛋白。因此，我们的数据表明，镉的凋亡和坏死的行动衰减bcl-2。
We examined the effects of cadmium on the bcl-2 family of proteins--bcl-2, bax, bad, and bcl-xS/L--in cadmium-induced cytotoxicity. Addition of 10 microM cadmium to cultured porcine kidney LLC-PK(1) cells caused apoptosis. Western blot analyses revealed that cadmium markedly increased endogenous bcl-2 protein (to 3-4 times the level in wild-type cells) earlier than metallothionein induction, but that the metal did not enhance the induction of bax, bad, or bcl-xS proteins. Cadmium also induced the transcript of bcl-2, with the amount of bcl-2 reaching a maximum at 1-2 hr of exposure; this increase occurred earlier than cadmium-induced increase in the protooncogene such as c-myc. A cadmium-induced increase in endogenous bcl-2 protein was also seen in rat primary thymocytes. Overexpression of the bcl-2 protein by gene transfection prevented cadmium-induced apoptosis. Following the detection of apoptosis, lactate dehydrogenase release in the culture medium (a marker of necrosis) was observed, and this release was also inhibited by overexpression of bcl-2. Electron microscopic observations also supported the fact that cadmium induced apoptotic chromatin condensation at an early stage of exposure, followed by necrotic features of the cells, both of which were also inhibited by overexpression of bcl-2 proteins. Thus, our data demonstrated that both apoptotic and necrotic actions of cadmium were attenuated by bcl-2.