Inhibition of the JNK signalling pathway enhances proteasome inhibitor-induced apoptosis of kidney cancer cells by suppression of BAG3 expression
Inhibition of the JNK signalling pathway enhances proteasome inhibitor-induced apoptosis of kidney cancer cells by suppression of BAG3 expression
复制标题
抑制 JNK 信号通路通过抑制 BAG3 表达增强蛋白酶体抑制剂诱导的肾癌细胞凋亡
DOI：
10.1111/j.1476-5381.2009.00455.x
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发表时间：
2009-11-01
影响因子：
7.3
通讯作者：
Du, Zhen-Xian
中科院分区：
文献类型：
--
作者：
Wang, Hua-Qin;Liu, Bao-Qin;Du, Zhen-Xian
背景和目的：蛋白酶体抑制剂是一类新型的抗肿瘤药物，对血液病和实体瘤具有临床疗效。抗凋亡蛋白BAG 3是Bcl-2相关的凋亡基因家族的成员。我们以前已经表明，BAG 3是上调后，暴露于蛋白酶体抑制剂和BAG 3的抑制敏感细胞凋亡诱导的蛋白酶体抑制。然而，蛋白酶体抑制诱导BAG 3表达的机制仍不清楚，本实验旨在阐明这些mechanism.Experimental approach：蛋白酶体抑制剂MG 132对有丝分裂信号通路激活的影响进行了评估，在肾癌细胞（A498，Caki 1，Caki 2），与蛋白质印迹。针对单个促有丝分裂信号通路的特异性抑制剂、实时逆转录-聚合酶链反应和荧光素酶报告基因测定被用于研究促有丝分裂信号通路在蛋白酶体抑制后BAG 3诱导中的作用。使用膜联蛋白V/碘化丙啶染色和随后的流式细胞仪评估细胞死亡。关键结果：MG 132激活了几种关键的促有丝分裂信号通路，包括细胞外信号调节激酶（ERK）、c-Jun N末端激酶（JNK）和p38有丝分裂原激活蛋白激酶（MAPK）活性。MG 132对BAG 3的诱导作用可通过阻断JNK而非ERK 1/2和p38 MAPK信号通路来抑制。此外，SP 600125和显性阴性JNK 1抑制BAG 3启动子驱动的报告基因表达。此外，JNK通路的激活诱导了MG 132处理后肾癌细胞的BAG。结论：我们的研究结果表明，JNK通路通过介导BAG 3的诱导与蛋白酶体抑制的保护性反应有关。
Background and purpose:Proteasome inhibitors represent a novel class of anti-tumour agents that have clinical efficacy against haematological and solid cancers. The anti-apoptotic protein BAG3 is a member of the Bcl-2-associated athanogene family. We have previously shown that BAG3 is up-regulated after exposure to proteasome inhibitors and that inhibition of BAG3 sensitized cells to apoptosis induced by proteasome inhibition. However, the mechanisms by which proteasome inhibition induced BAG3 expression remained unclear and the present experiments were designed to elucidate these mechanisms.Experimental approach:Effects of the proteasome inhibitor MG132 on activation of mitogenic signalling pathways were evaluated in kidney cancer cells (A498, Caki1, Caki2), with Western blotting. Specific inhibitors against individual mitogenic signalling pathways, real-time reverse transcription-polymerase chain reaction and luciferase reporter assays were used to investigate the roles of mitogenic signalling pathways in BAG3 induction after proteasome inhibition. Cell death was evaluated using Annexin V/propidium iodide staining and subsequent FACS.Key results:MG132 activated several key mitogenic signalling pathways including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) activities. Induction of BAG3 by MG132 was inhibited by blocking JNK, but not ERK1/2 and p38 MAPK signalling pathways. In addition, SP600125 and dominant-negative JNK1 suppressed BAG3 promoter-driven reporter gene expression. Furthermore, activation of the JNK pathway induced BAG in kidney cancer cells after treatment with MG132.Conclusions and implications:Our results suggested that the JNK pathway was associated with the protective response against proteasome inhibition, by mediating induction of BAG3.