Discovery of a Small‐Molecule pBcl‐2 Inhibitor that Overcomes pBcl‐2‐Mediated Resistance to Apoptosis
Discovery of a Small‐Molecule pBcl‐2 Inhibitor that Overcomes pBcl‐2‐Mediated Resistance to Apoptosis
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DOI：
10.1002/cbic.201402639
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发表时间：
2015-03
期刊：
影响因子：
3.2
通讯作者：
T. Song;Xiaoyan Yu;Yubo Liu;Xiangqian Li;G. Chai;Zhichao Zhang
中科院分区：
文献类型：
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作者：
T. Song;Xiaoyan Yu;Yubo Liu;Xiangqian Li;G. Chai;Zhichao Zhang
尽管对BH3类似物，如ABT-737和S1的抗性机制中，Bc l-2的磷酸化作用仍有争议。我们发现S1类似物S1-16是PBCL-2的小分子抑制物。S1-16通过阻断EEE-Bcl-2或天然PBCL-2与Bax和Bak的相互作用，有效地杀死表达EEE-Bcl-2(模拟磷酸化的T69E、S70E和S87E突变体)的HL-60细胞和高表达PBCL-2的细胞。体外结合实验表明，S1-16能与BH3结合(IC50=0.12μM，IC50=0.12μM)，也能与非磷酸化Bcl2结合。然而，ABT737和S1对eEE-Bcl2的亲和力(IC50分别为1.43和10μM)明显弱于npBcl2(IC50分别为0.011和0.74μM)。首次阐明了BH3结合槽中的变构效应是通过环区的bcl2磷酸化来实现的。
Although the role of Bcl‐2 phosphorylation is still under debate, it has been identified in a resistance mechanism to BH3 mimetics, for example ABT‐737 and S1. We identified an S1 analogue, S1‐16, as a small‐molecule inhibitor of pBcl‐2. S1‐16 efficiently kills EEE‐Bcl‐2 (a T69E, S70E, and S87E mutant mimicking phosphorylation)‐expressing HL‐60 cells and high endogenously expressing pBcl‐2 cells, by disrupting EEE‐Bcl‐2 or native pBcl‐2 interactions with Bax and Bak, followed by apoptosis. In vitro binding assays showed that S1‐16 binds to the BH3 binding groove of EEE‐Bcl‐2 (Kd=0.38 μM by ITC; IC50=0.16 μM by ELISA), as well as nonphosphorylated Bcl‐2 (npBcl‐2; Kd=0.38 μM; IC50=0.12 μM). However, ABT‐737 and S1 had much weaker affinities to EEE‐Bcl‐2 (IC50=1.43 and >10 μM, respectively), compared with npBcl‐2 (IC50=0.011 and 0.74 μM, respectively). The allosteric effect on BH3 binding groove by Bcl‐2 phosphorylation in the loop region was illustrated for the first time.