Mixed lineage kinase 3 connects reactive oxygen species to c-Jun NH2-terminal kinase-induced mitochondrial apoptosis in genipin-treated PC3 human prostate cancer cells
Mixed lineage kinase 3 connects reactive oxygen species to c-Jun NH2-terminal kinase-induced mitochondrial apoptosis in genipin-treated PC3 human prostate cancer cells
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DOI：
10.1016/j.bbrc.2007.07.165
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发表时间：
2007-10-19
影响因子：
3.1
通讯作者：
Kim, Byung-Chul
中科院分区：
文献类型：
--
作者：
Hong, Hye-Young;Kim, Byung-Chul
京尼平（genipin）是京尼平苷（geniposide）的糖苷配基，通过NADPH氧化酶-活性氧（ROS）-c-Jun氨基末端激酶（JNK）依赖的线粒体途径诱导人肝癌细胞凋亡。这项持续的工作旨在确定混合谱系激酶3（MLK 3）是京尼平诱导的细胞死亡信号传导中ROS和JNK之间的关键介导剂。在PO人前列腺癌细胞中，京尼平以浓度和时间依赖性方式刺激MLK 3活性。用显性阴性形式的MLK 3稳定转染的PC 3细胞对亚G1凋亡细胞的群体、半胱天冬酶的活化、线粒体膜电位的崩溃和由京尼平触发的细胞色素e的释放较不敏感，表明MLK 3在京尼平信号传导至凋亡性细胞死亡中的关键作用。二苯基碘铵（DPI），NADPH氧化酶的特异性抑制剂，显着抑制京尼平处理的细胞中的ROS的产生和MLK 3磷酸化。JNK特异性抑制剂SP 0600125预处理可抑制京尼平诱导的细胞凋亡，但MEK 1/2特异性抑制剂U 0126和p38特异性抑制剂PD 169316均不能抑制京尼平诱导的细胞凋亡。值得注意的是，在表达显性阴性MLK 3突变体的PC 3-EGFP-MLK 3（K144 R）细胞中，京尼平诱导的JNK磷酸化和c-Jun诱导均被显著抑制。综上所述，我们的观察表明京尼平信号传导至PC 3细胞的凋亡是通过激活ROS依赖性MLK 3介导的，这导致下游JNK的激活。(C)2007年爱思唯尔公司All rights reserved.
It has been reported that genipin, the aglycone of geniposide, induces apoptotic cell death in human hepatoma cells via a NADPH oxidase-reactive oxygen species (ROS)-c-Jun NH2-terminal kinase (JNK)-dependent activation of mitochondrial pathway. This continuing work aimed to define that mixed lineage kinase 3 (MLK3) is a key mediator, which connect between ROS and JNK in genipin-induced cell death signaling. In PO human prostate cancer cells, genipin stimulated MLK3 activity in concentration- and time-dependent manner. The PC3 cells stably transfected with dominant-negative form of MLK3 was less susceptible to population of the sub-Gl apoptotic cells, activation of caspase, collapse of mitochondrial membrane potential, and release of cytochrome e triggered by genipin, suggesting a crucial role of MLK3 in genipin signaling to apoptotic cell death. Diphenylenciodonium (DPI), a specific inhibitor of NADPH oxidase, markedly inhibited ROS generation and MLK3 phosphorylation in the genipin-treated cells. Pretreatment with SP0600125, a specific inhibitor of JNK but neither U0126, a specific inhibitor of MEK1/2 nor PD169316, a specific inhibitor of p38 suppressed genipin-induced apoptotic cell death. Notably, both the phosphorylation of JNK and induction of c-Jun induced by genipin were markedly inhibited in PC3-EGFP-MLK3 (K144R) cells expressing a dominant-negative MLK3 mutant. Taken together, our observations suggest genipin signaling to apoptosis of PC3 cells is mediated via activation of ROS-dependent MLK3, which leads to downstream activation of JNK. (C) 2007 Elsevier Inc. All rights reserved.