Analysis of the RNA-interactome governing oncogenesis of osteosarcoma

骨肉瘤是儿童、青少年和年轻人最常见的原发性恶性骨肿瘤。长期存活率从仅手术切除肿瘤的约10%提高到20世纪70年代引入化疗的约60%-75%。然而，由于这一进展已经取得了进展。40年前，存活率几乎没有进一步提高。开发新的治疗方案和获得对骨肉瘤生物学的新见解的挑战之一是缺乏反映这种疾病的关键特征的临床前模型。因此，在我们以前的工作中，我们建立了一系列临床前原位小鼠和细胞培养模型，忠实地反映了原发性肿瘤的重要特征。因此，这些模型代表了有价值的工具，分析骨肉瘤的肿瘤发生机制，并在临床前开发新的治疗策略。尽管广泛的基因组，表观基因组和转录组学分析，没有统一的遗传机制解释骨肉瘤的发展。该项目基于RNA：蛋白质相互作用在骨肉瘤的肿瘤发生中起关键作用的假设。我们现在已经利用了申请人之一的发明和活细胞中全局RNA相互作用组分析方法的改进以及另一个申请人的实验室中患者来源的临床前模型的开发。因此，我们的目的是深入了解以前未被认识到的基因调控水平在骨肉瘤的肿瘤发生。该项目的总体目标是（1）全面解读正常成骨细胞和间充质细胞与患者来源的骨肉瘤细胞之间的RNA相互作用组的差异（2）研究同一患者从首次诊断到复发的演变过程中骨肉瘤细胞的RNA相互作用组的动力学，（3）功能验证无偏全局分析得出的最高评分候选者，和（4）鉴定和测试骨肉瘤细胞中的潜在治疗靶点，其基于它们在骨肉瘤细胞中的特异性、临床数据、癌症演变的动力学和RNA结合蛋白的翻译后修饰。

Osteosarcoma is the most common primary malignant bone tumor in children, adolescents and young adults. Long term survival has improved from about 10% with surgical resection of the tumor alone to about 60%-75% with the introduction of chemotherapy in the 1970ies. However, since this progress has been achieved approx. 40 years ago, there has been almost no further improvement of survival rates. One of the challenges of developing new treatment options and of gaining new insights into the biology of osteosarcoma has been the lack of preclinical models reflecting key characteristics of this disease. In our previous work we have thus established a series of preclinical orthotopic mouse and cell culture models faithfully reflecting important features of the primary tumors. These models thus represent valuable tools to analyze mechanisms of the oncogenesis of osteosarcoma and to preclinically develop novel treatment strategies. Despite extensive genomic, epigenomic and transcriptomic analyses there is no unifying genetic mechanism explaining the development of osteosarcomas. This project is based on the hypothesis that RNA:protein interactions play key roles in the oncogenesis of osteosarcoma. We have now leveraged the invention and the refinement of the methodology for global RNA-interactome analysis in living cells by of one of the applicants and the development of patient-derived preclinical models in the laboratory of the other. We thus aim at gaining insight into a previously unrecognized level of gene regulation in the oncogenesis of osteosarcoma. The overall objectives of this project are (1) to comprehensively decipher the differences of the RNA-interactomes between normal osteoblasts and mesenchymal cells vs. patient-derived osteosarcoma cells (2) to study the dynamics of RNA-interactomes of osteosarcoma cells during the evolution from first diagnosis to relapse in the same patient, (3) to functionally validate top-scoring candidates resulting from the unbiased global analysis, and (4) to identify and test potential therapeutic targets in osteosarcoma cells which are based on their specificity in osteosarcoma cells, clinical data, dynamics in cancer evolution and on post-translational modifications of the RNA-binding proteins.