The BH3 α-Helical Mimic BH3-M6 Disrupts Bcl-XL, Bcl-2, and MCL-1 Protein-Protein Interactions with Bax, Bak, Bad, or Bim and Induces Apoptosis in a Bax- and Bim-dependent Manner
The BH3 α-Helical Mimic BH3-M6 Disrupts Bcl-XL, Bcl-2, and MCL-1 Protein-Protein Interactions with Bax, Bak, Bad, or Bim and Induces Apoptosis in a Bax- and Bim-dependent Manner
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DOI：
10.1074/jbc.m110.203638
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发表时间：
2011-03-18
影响因子：
4.8
通讯作者：
Sebti, Said M.
中科院分区：
文献类型：
--
作者：
Kazi, Aslamuzzaman;Sun, Jiazhi;Sebti, Said M.
癌细胞存活的关键标志是逃避凋亡。这通常是由于抗凋亡蛋白如Bcl-2、Bcl-X-L和Mcl-1的过表达，其结合促凋亡蛋白如Bax、巴克、Bad和Bim的BH 3 α-螺旋结构域，并抑制它们的功能。我们设计了一种BH 3 α-螺旋模拟物BH 3-M6，其与Bcl-X-L和Mcl-1结合，并在体外阻止它们与荧光标记的巴克-或Bim-BH 3肽结合。使用几种方法，我们证明了BH 3-M6是一种泛Bcl-2拮抗剂，其抑制Bcl-X-L、Bcl-2和Mcl-1与多结构域Bax或巴克的结合，或在无细胞系统和完整的人类癌细胞中仅BH 3的Bim或Bad的结合，释放促凋亡蛋白以诱导凋亡。BH 3-M6对这些蛋白质-蛋白质相互作用的破坏与细胞色素c从线粒体释放、半胱天冬酶-3活化和PARP裂解相关。使用半胱天冬酶抑制剂和Bax和巴克siRNA，我们证明了BH 3-M6诱导的细胞凋亡是半胱天冬酶和Bax依赖的，但不是巴克依赖的。此外，BH 3-M6破坏Bcl-X-L/Bim、Bcl-2/Bim和Mcl-1/Bim蛋白质-蛋白质相互作用，释放Bim以诱导人类癌细胞的凋亡，所述人类癌细胞的肿瘤存活依赖于Bim与Bcl-X-L、Bcl-2或Mcl-1的中和。最后，BH 3-M6使细胞对蛋白酶体抑制剂CEP-1612诱导的细胞凋亡敏感。
A critical hallmark of cancer cell survival is evasion of apoptosis. This is commonly due to overexpression of anti-apoptotic proteins such as Bcl-2, Bcl-X-L, and Mcl-1, which bind to the BH3 alpha-helical domain of pro-apoptotic proteins such as Bax, Bak, Bad, and Bim, and inhibit their function. We designed a BH3 alpha-helical mimetic BH3-M6 that binds to Bcl-X-L and Mcl-1 and prevents their binding to fluorescently labeled Bak- or Bim-BH3 peptides in vitro. Using several approaches, we demonstrate that BH3-M6 is a pan-Bcl-2 antagonist that inhibits the binding of Bcl-X-L, Bcl-2, and Mcl-1 to multi-domain Bax or Bak, or BH3-only Bim or Bad in cell-free systems and in intact human cancer cells, freeing up pro-apoptotic proteins to induce apoptosis. BH3-M6 disruption of these protein-protein interactions is associated with cytochrome c release from mitochondria, caspase-3 activation and PARP cleavage. Using caspase inhibitors and Bax and Bak siRNAs, we demonstrate that BH3-M6-induced apoptosis is caspase- and Bax-, but not Bak-dependent. Furthermore, BH3-M6 disrupts Bcl-X-L/Bim, Bcl-2/Bim, and Mcl-1/Bim protein-protein interactions and frees up Bim to induce apoptosis in human cancer cells that depend for tumor survival on the neutralization of Bim with Bcl-X-L, Bcl-2, or Mcl-1. Finally, BH3-M6 sensitizes cells to apoptosis induced by the proteasome inhibitor CEP-1612.