Coherence between Cellular Responses and in Vitro Splicing Inhibition for the Anti-tumor Drug Pladienolide B and Its Analogs
Coherence between Cellular Responses and in Vitro Splicing Inhibition for the Anti-tumor Drug Pladienolide B and Its Analogs
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DOI：
10.1074/jbc.m113.515536
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发表时间：
2014-01-24
影响因子：
4.8
通讯作者：
Jurica, Melissa S.
中科院分区：
文献类型：
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作者：
Effenberger, Kerstin A.;Anderson, David D.;Jurica, Melissa S.
白花烯内酯B(PB)是一种针对剪接体SF3B1亚单位的有效癌细胞生长抑制物。该化合物作为一种潜在的化疗药物以及研究SF3B1在剪接和癌症发展中的功能的工具，受到了相当大的兴趣。PB是一种细菌天然产物，其分子结构包含一个12元大环内酯环和一个延伸的含环氧基侧链。利用一种新颖的简洁的对映选择性合成方法，我们合成了一系列的PB结构类似物和结构相关的化合物Herboxdiene。我们发现，PB侧链上的两个甲基，以及大环内酯环的一个特征，是抑制体外剪接所必需的。出乎意料的是，我们发现环氧基对PB效力的贡献很小，对活性来说并不是绝对必要的。大环外至少两个手性中心的取向对PB的活性没有影响。重要的是，类似物在体外抑制剪接的能力与它们在一系列细胞检测中的效果直接相关。这些影响可能源于抑制细胞中的一些内源性剪接事件，就像之前报道的结构不同的SF3B1抑制剂Spliceostatin A一样，我们的数据支持这样的观点，即PB对细胞的影响来自于它损害SF3B1在剪接中功能的能力，也证明了PB支架的简化是可行的。
Pladienolide B (PB) is a potent cancer cell growth inhibitor that targets the SF3B1 subunit of the spliceosome. There is considerable interest in the compound as a potential chemotherapeutic, as well as a tool to study SF3B1 function in splicing and cancer development. The molecular structure of PB, a bacterial natural product, contains a 12-member macrolide ring with an extended epoxide-containing side chain. Using a novel concise enantioselective synthesis, we created a series of PB structural analogs and the structurally related compound herboxidiene. We show that two methyl groups in the PB side chain, as well as a feature of the macrolide ring shared with herboxidiene, are required for splicing inhibition in vitro. Unexpectedly, we find that the epoxy group contributes only modestly to PB potency and is not absolutely necessary for activity. The orientations of at least two chiral centers off the macrolide ring have no effect on PB activity. Importantly, the ability of analogs to inhibit splicing in vitro directly correlated with their effects in a series of cellular assays. Those effects likely arise from inhibition of some, but not all, endogenous splicing events in cells, as previously reported for the structurally distinct SF3B1 inhibitor spliceostatin A. Together, our data support the idea that the impact of PB on cells is derived from its ability to impair the function of SF3B1 in splicing and also demonstrate that simplification of the PB scaffold is feasible.