剪接因子RBM10在肺腺癌中的功能与作用机制研究

RNA splicing defects have been proposed to make significant contributions to cancer, but their specific effects and underlying mechanisms remain largely unknown. Mutations in the RNA binding protein and splicing regulator RBM10 are frequently observed in lung adenocarcinoma (LUAD). In our previous studies, we have elucidated molecular mechanisms of RBM10-mediated alternative splicing and RBM10-mediated autoregulation and cross-regulation of its paralog RBM5. We have also characterized the functional consequences of LUAD-associated RBM10 mutations. In addition, we and others have shown that RBM10 suppresses LUAD cell proliferation in part by regulating the splicing of its target gene NUMB. In this study, we propose to: i) systematically investigate the functional impacts of RBM10 on LUAD pathogenesis using LUAD and lung epithelium-derived cell lines, xenograft nude mice and Rbm10 conditional knockout LUAD mice models; ii) identify RBM10-mediated changes in splicing and gene expression, explore the functions of distinct isoforms for key RBM10 target genes and perform rescue experiments to elucidate molecular mechanisms underlying RBM10 contributions to LUAD; iii) explore the clinical implications of the above findings using tissue samples from Chinese LUAD patients and data from the TCGA database. Taken together, the investigations described in this proposal will elucidate the functions, underlying molecular mechanisms and clinical implications of RBM10-mediated splicing in LUAD, and thereby facilitate the development of new approaches to its diagnosis and treatment. The experimental and computational methods established here should also be widely applicable to functional and mechanistic studies of other cancer-associated splicing regulators, thereby greatly deepening the mechanistic understandings of splicing defects in cancer.

RNA剪接异常是肿瘤的一个新的标志性分子特征，然而大量肿瘤相关剪接异常的功能及形成的分子机制未被阐明。RBM10是一个在肺腺癌中高频率突变的剪接因子，我们前期的研究揭示了RBM10介导剪接调控、其负向调控自身及RBM5表达的分子机制，并对肺腺癌相关的RBM10突变进行了功能分析。本研究中，我们将：1）构建干预RBM10的肺腺癌与肺上皮细胞系、条件敲除Rbm10的肺腺癌小鼠模型，进行系统功能分析，揭示RBM10对肺腺癌发生发展的功能性影响；2）鉴定并验证RBM10引起的剪接变化，揭示其关键靶标基因的不同剪接异构体的功能，并进行功能挽救实验，阐明RBM10在肺腺癌中发挥功能的分子机制；3）通过临床样本实验验证及关联分析，揭示研究结果的临床意义。该研究将阐明RBM10及其调控的靶标基因在肺腺癌中的功能、作用机制及临床意义，促进其在肺腺癌诊断、治疗中的应用，推动剪接异常在肿瘤中的功能与机制研究。

RNA剪接异常是肿瘤的一个新标志性分子特征，然而大量肿瘤相关剪接异常的功能及分子机制未被阐明。肺癌是世界范围内癌症致死的首要原因，剪接异常在肺癌中普遍存在且发挥重要作用，其中剪接因子RBM10在肺腺癌这一最常见肺癌亚型中高频率突变。本研究中，我们运用细胞、小鼠模型与临床样本，发现：肺腺癌中RBM10突变主要为功能缺失突变，引起广泛的剪接变化，这些剪接变化可作为肺腺癌预后评价的新分子标记物；RBM10通过调控翻译起始因子基因EIF4H的剪接从而抑制肺腺癌进展；EIF4H包含外显子5的长剪接亚型在多种癌症中高表达，对肺腺癌细胞增殖及成瘤至关重要，选择性促进原癌基因CCND1的蛋白表达，可作为肺癌潜在治疗新靶标；这些研究结果发表在EBioMedicine上。在此基础上进一步利用条件敲除小鼠模型揭示Rbm10或Trp53缺失促进EGRF突变肺癌的发生发展，相关论文完成修稿待发表。受邀在Science China Life Sciences上撰写综述，系统总结了癌症中RNA剪接异常及治疗策略的研究进展。本项目的研究揭示了剪接因子RBM10突变在肺腺癌中的驱动功能与新分子机制，为肺癌提供了基于RBM10及其靶标基因剪接的诊断、治疗新靶标，并为剪接异常及其与mRNA翻译的交互作用在肿瘤中的研究与临床转化提供了重要启示。