Rational targeting of protein translation of cancer treatments

描述(申请人提供)：靶向蛋白质翻译用于癌症治疗是一种有吸引力的策略，通过剥夺癌细胞的必要营养来限制它们的增殖。然而，目前可用的药物针对的是蛋白质翻译机制的组件，这些组件也是正常细胞功能所必需的。在这里，我们建议开发一种更合理的方法，通过靶向癌细胞中的蛋白质翻译调节因子。我们的初步数据表明，应激激活的RNA结合蛋白hnRNP A18通过调节防止细胞凋亡和/或促进DNA修复的关键蛋白的表达，赋予癌细胞生长优势。HnRNP A18通过与其靶向转录产物的3‘UTRs中的特定RNA签名基序结合并与一般翻译机制相互作用来增加蛋白质翻译。因此，靶向hnRNP A18可以阻止hnRNP A18过度表达的癌细胞中的蛋白质翻译，并且只会影响含有hnRNP A18签名基序的转录本的翻译。我们的工作假设是，合理靶向hnRNP A18将抑制致力于赋予癌细胞生长优势的特定RNA转录本的翻译。为了验证这一假设，我们设计了三个具体目标。目的1：确定hnRNP A18在肿瘤细胞对抗癌药物敏感性中的作用。HnRNPA18的水平将被操纵，细胞对临床相关剂量的抗癌药物或辐射的敏感性将通过克隆生存分析、细胞凋亡和DNA修复(γH2AX)进行分析。目的：鉴定hnRNP A18与其靶向转录本的生化和功能结合活性，评价hnRNP A18在肿瘤进展中的作用。这将通过系统地分析与hnRNP A18 RNA基序的不同茎和凸起的结合，并评估hnRNP A18磷酸化对与这些不同RNA结构结合的影响来实现。目的3：确定hnRNP A18的三维结构并鉴定hnRNP A18与RNA的结合界面。在没有APO和存在3‘UTRRNA(签名基序)的情况下，未磷酸化和磷酸化的hnRNP A18的结构将在溶液中通过核磁共振(NMR)谱来解析。我们的长期目标是开发能够靶向hnRNP A18的药物来控制并可能阻止癌症的进展。这可以通过解决hnRNP A18的三维结构和使用计算机辅助药物设计(CADD)技术来识别可以靶向hnRNP A18的小分子来实现。

DESCRIPTION (provided by applicant): Targeting protein translation for cancer therapy is an attractive strategy to limit cancer cells proliferation by depriving them of essential nutriments. However, the currently available drugs target components of the protein translational machinery that are also essential for normal cell functions. Here, we propose to develop a more rational approach by targeting a regulator of protein translation in cancer cells. Our preliminary data indicate that the stress-activated RNA binding protein hnRNP A18 confers growth advantage to cancer cells by regulating the expression of key proteins that prevent apoptosis and/or increase DNA repair. hnRNP A18 increases protein translation by binding to a specific RNA signature motif in the 3'UTRs of its targeted transcripts and interacting with the general translational machinery. Therefore, targeting hnRNP A18 could prevent protein translation in cancer cells, where hnRNP A18 is over expressed, and would only affect the translation of transcripts harboring hnRNP A18 signature motif. Our working hypothesis is that rational targeting of hnRNP A18 will inhibit the translation of specific RNA transcripts devoted to confer growth advantages to cancer cells. To test this hypothesis three specific Aims have been designed. Aim 1: Determine the role of hnRNP A18 in cancer cells sensitivity to anticancer treatments. Levels of hnRNP A18 will be manipulated and the cellular sensitivity to clinically relevant doses of anticancer drugs or radiation will be analyzed by clonogenic survival assays, apoptosis and DNA repair (γH2AX). Aim 2: Characterize the biochemical and functional binding activity of hnRNP A18 to its targeted transcripts and evaluate the effect of hnRNP A18 on cancer progression. This will be performed by systematically analyzing binding to the different stems and bulges of the hnRNP A18 RNA motif and evaluating the effect of hnRNP A18 phosphorylation on the binding to these different RNA structures. Aim 3: Determine the three-dimensional structure of hnRNP A18 and identify the hnRNP A18-RNA binding interface. The structures of unphosphorylated and phosphorylated hnRNP A18 in the absence (apo) and presence of 3'UTR RNA (signature motif) will be solved in solution by Nuclear Magnetic Resonance (NMR) spectroscopy. Our long term goal is to develop drugs that could target hnRNP A18 to control and possibly stop cancer progression. This could be accomplished by solving hnRNP A18 three dimensional structure and use computer-aided drug design (CADD) technology to identify small molecules that could target hnRNP A18.