肿瘤细胞外泌体通过miR-195a-5p和Angptl2蛋白对肿瘤恶病质骨骼肌萎缩与脂肪脂解的诱导作用及机制研究

Cancer cachexia is a major complication of various malignancies, accompanied with severe loss of skeletal muscle and adipose tissue. The research on the role of exosomes in muscle atrophy and lipolysis of cancer cachexia has attracted more and more interest of researchers. In our preliminary study, it was found that exosomes secreted by C26 cells (cachexia-inducing cell line) can induce muscle atrophy and lipolysis in vitro. Using proteomic analysis and transcriptomics analysis technologies, miR-195a-5p and Angptl2 were identified as possible active miRNA and protein in C26 exosomes, respectively. In the present project, based on our preliminary results, we will focus on studying the signal transduction of exosomes in cancer cachexia. Firstly, we would try to confirm the roles of C26 exosomes and its active components in inducing muscle atrophy and lipolysis using in vitro and in vivo cancer cachexia models. Secondly, the possible target genes of miR-195a-5p and possible down-stream signals of Angptl2 would be searched. Thirdly, we would try to reveal the effects of C26 exosomes in regulating miR-195a-5p-smad7/sirt1/Zfp423 and Angptl2-ROS signaling pathways which result in muscle atrophy and fat lipolysis. The aim of this project is to clarify the mechanisms of C26 exosomes in inducing cancer cachexia, and to explore new targets for the therapy of cancer cachexia.

肿瘤恶病质是各种恶性肿瘤患者的主要并发症，以骨骼肌与脂肪组织的消耗最为明显。外泌体在肿瘤恶病质骨骼肌与脂肪组织消耗中的参与作用日益受到重视。我们前期研究发现，恶病质性C26肿瘤细胞分泌的外泌体能够诱导体外肌肉萎缩和脂肪脂解，应用蛋白质组学与转录组学分析发现，外泌体携带的miR-195a-5p与Angptl2蛋白可能是诱导肌萎缩与脂肪脂解的效应分子。本课题拟在前期工作的基础上，以外泌体介导的信号传导为主线：①从细胞和动物水平进一步确证C26外泌体及其效应分子诱导肿瘤恶病质骨骼肌与脂肪组织消耗的作用；②寻找miR-195a-5p的靶基因和Angptl2蛋白的下游信号；③明确C26外泌体通过miR-195a-5p-smad7/sirt1/Zfp423信号通路和Angptl2-ROS信号通路诱导肌萎缩与脂解的作用，揭示C26外泌体参与肿瘤恶病质病理发展的分子机制，拓展肿瘤恶病质治疗的新思路。

肿瘤恶病质是各种恶性肿瘤患者的主要并发症和主要致死因素之一，以骨骼肌与脂肪组织的消耗最为明显。肿瘤恶病质病理机制尚不够清楚，本项目对致恶病质C26结肠癌细胞分泌的外泌体及其活性miRNA和蛋白成分参与肿瘤恶病质肌萎缩与脂解的作用及其机制进行了深入的研究：①应用体外、体内肌萎缩与脂肪降解模型，明确了C26肿瘤细胞外泌体对骨骼肌与脂肪组织消耗的诱导作用；②采用蛋白质组学与转录组学分析，结合分子生物学与肿瘤恶病质细胞和动物模型，寻找并验证了C26 外泌体中调控肿瘤恶病质肌萎缩和脂肪降解的miRNA 与蛋白效应分子；③研究阐明了C26 外泌体中miR-195a-5p、miR-125b-1-3p调控肿瘤恶病质肌萎缩的分子作用机制，与靶向Bcl-2基因，激活凋亡信号通路诱导骨骼肌萎缩有关；④研究阐明了C26外泌体携带的GDF15蛋白调控肿瘤恶病质肌萎缩的分子作用机制，GDF15通过激活凋亡信号诱导骨骼肌萎缩。本项目的研究结果揭示了肿瘤外泌体及其活性成分介导的信号通路在肿瘤恶病质的发生发展中的参与机制和地位，增加了对肿瘤恶病质病理机制的了解，拓展肿瘤恶病质治疗的新思路，具有较高的科学意义和学术价值；针对肿瘤外泌体分泌、外泌体中活性成分miRNA和蛋白，开发抗肿瘤恶病质新药，具有较好的应用前景和实用价值。本项目取得的研究成果包括6篇SCI研究文章和1篇中文核心期刊综述，6篇SCI研究文章均发表在相应研究领域的权威杂志，5篇文章的影响因子均大于5分（其中3篇大于10分）；作为研究课题协助培养了3名博士研究生和3名硕士研究生。圆满完成了项目设定的研究计划和预期研究目标。