The impact of the RNA-binding protein hnRNP-A1 on translation in inflammation-associated tumorigenesis

RNA结合蛋白hnRNP-A1对炎症相关肿瘤发生中翻译的影响

• 批准号: 240138667
• 负责人: Privatdozent Dr. Tobias Schmid
• 金额: --
• 依托单位: Institut für Biochemie I: Pathobiochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/240138667?language=en
• 关键词: impact; RNA; binding; protein; hnRNP

The inflammatory tumor microenvironment is shaped by infiltrating immune cells, most notably macrophages, which release pro-inflammatory mediators that contribute to malignant transformation. In line, inflammatory conditions are widely accepted to support the process of tumorigenesis. We have previously shown that macrophage-associated inflammatory conditions, in addition to inducing transcriptional changes, elicit translational changes in tumor cells that foster tumor development. Preliminary data imply that hnRNP-A1 could play an important role in the regulation of cap-independent translation changes under these conditions. Thus, we now aim to identify and characterize inflammation-induced translational changes in tumor cells that depend on the RNA-binding protein hnRNP-A1. Using polysomal fractionation, we will assess hnRNP-A1-dependent translational changes in tumor cells under inflammatory conditions. In addition, we will determine the exact binding sites of hnRNP-A1 on its mRNA targets by PAR-CLIP (photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation) analysis. Combining both approaches we will identify translationally regulated hnRNP-A1 targets that interact with hnRNP-A1 via their 5' untranslated region. These targets will be analyzed for the presence of internal ribosome entry site (IRES)-elements facilitating cap-independent initiation of translation. Determination of shared sequences or structural motifs will predict hnRNP-A1 responsive IRESs. Further analyses aim at identifying potential co-IRES trans-acting factors (ITAFs) contributing the IRES-dependent translation of selected hnRNP-A1 targets. Finally, the elucidation of the macrophage-dependent inflammatory factors contributing to the altered IRES-activities and the contributing signaling cascades will provide the basis for translation-targeted interventions.

炎症性肿瘤微环境是由浸润性免疫细胞（尤其是巨噬细胞）形成的，它们释放促炎介质，促进恶性转化。因此，炎症条件被广泛认为支持肿瘤发生过程。我们之前已经表明，巨噬细胞相关的炎症除了诱导转录变化外，还会引起肿瘤细胞的翻译变化，从而促进肿瘤的发展。初步数据表明，hnRNP-A1 在这些条件下可能在调节与帽无关的翻译变化中发挥重要作用。因此，我们现在的目标是识别和表征依赖于 RNA 结合蛋白 hnRNP-A1 的肿瘤细胞中炎症诱导的翻译变化。使用多核糖体分级分离，我们将评估炎症条件下肿瘤细胞中 hnRNP-A1 依赖性翻译变化。此外，我们将通过 PAR-CLIP（光激活核糖核苷增强交联和免疫沉淀）分析确定 hnRNP-A1 在其 mRNA 靶标上的确切结合位点。结合这两种方法，我们将鉴定翻译调节的 hnRNP-A1 靶标，这些靶标通过其 5' 非翻译区与 hnRNP-A1 相互作用。将分析这些靶标是否存在内部核糖体进入位点 (IRES) 元件，以促进与帽无关的翻译起始。共享序列或结构基序的确定将预测 hnRNP-A1 响应 IRES。进一步的分析旨在确定潜在的共 IRES 反式作用因子 (ITAF)，有助于选定 hnRNP-A1 靶标的 IRES 依赖性翻译。最后，阐明导致 IRES 活性改变的巨噬细胞依赖性炎症因子和信号级联将为翻译靶向干预提供基础。