Identification of small molecule inhibitors of Zcchc11 TUTase activity
Identification of small molecule inhibitors of Zcchc11 TUTase activity
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DOI：
10.1080/15476286.2015.1058478
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发表时间：
2015-08-03
期刊：
影响因子：
4.1
通讯作者：
Gregory, Richard I.
中科院分区：
文献类型：
--
作者：
Lin, Shuibin;Gregory, Richard I.
RNA结合蛋白Lin 28在早期胚胎发育过程中调节let-7家族microRNA（miRNAs）的表达。Lin 28将3末端尿苷酰转移酶（TUTase）Zcchc 11（TUT 4）和/或Zcchc 6（TUT 7）募集到前体let-7 RNA（pre-let-7）以选择性地阻断let-7生物合成。尿苷酸化的pre-let-7被下游核酸外切酶Dis 3l 2靶向降解，从而防止加工成成熟的let-7。通过上调Lin 28表达激活这种致癌途径可促进细胞转化，驱动小鼠模型中的肿瘤发生，并且经常在多种癌症中观察到。最近的原理验证实验表明，Zcchc 11敲低抑制了表达Lin 28的人类癌细胞的致瘤性，并将这种酶确定为人类恶性肿瘤的可能的新治疗靶点。然而，目前还没有已知的能够靶向这种新型酶的药理学试剂。在这项研究中，我们开发并应用了一种灵敏的生化检测，监测Zcchc 11活性。使用该测定，我们对大约15，000种化学物质进行了自动化高通量筛选，以鉴定推定的TUTase抑制剂。这些小分子中的几种被验证为Zcchc 11活性的特异性抑制剂。我们的研究结果证明了筛选TUTase抑制剂的可行性，并提出了一个相对简单的平台，可用于未来旨在恢复let-7在癌症中表达的药物发现工作。
The RNA-binding protein Lin28 regulates the expression of the let-7 family of microRNAs (miRNAs) during early embryonic development. Lin28 recruits the 3 terminal uridylyl transferase (TUTase) Zcchc11 (TUT4) and/or Zcchc6 (TUT7) to precursor let-7 RNA (pre-let-7) to selectively block let-7 biogenesis. Uridylated pre-let-7 is targeted for decay by the downstream exonuclease Dis3l2 thereby preventing processing to mature let-7. Activation of this oncogenic pathway via up-regulation of Lin28 expression promotes cellular transformation, drives tumorigenesis in mouse models, and is frequently observed in a wide variety of cancer. Recent proof-of-principle experiments showed that Zcchc11 knockdown inhibits the tumorigenicity of Lin28-expressing human cancer cells and established this enzyme as a possible new therapeutic target for human malignancies. However, there are currently no known pharmacological agents capable of targeting this novel enzyme. In this study we developed and applied a sensitive biochemical assay that monitors Zcchc11 activity. Using this assay we performed an automated high-throughput screen of approximate to 15,000 chemicals to identify putative TUTase inhibitors. Several of these small molecules were validated as specific inhibitors of Zcchc11 activity. Our results demonstrate the feasibility of screening for TUTase inhibitors and present a relatively simple platform that can be exploited for future drug discovery efforts aimed at restoring let-7 expression in cancer.