miRNA调控舌鳞癌细胞线粒体分裂和化疗敏感性的机制研究

To improve the treatment efficacy of advanced tongue squamous cell carcinoma(TSCC), it's necessary to enhance the chemosensitivity. Recently, studies revealed that mitochondrial fission mediated cell apoptosis and played important roles in many diseases, but its role in regulating tumor chemosensitivity remains unclear. Our preliminary experiment demonstrated that cisplatin treatment could increase TSCC cell apoptosis by inducing mitochondrial fission. Regulatory factors of mitochondrial fission influenced cisplatin sensitivity, and their expression were regulated at post-transcription level. Combining our other studies on miRNAs regulating biological characteristics of tongue squamous cell carcinoma, we will investigate functions of miRNA in regulating Drp1 and its receptors Fis1, Mff and Mid49/Mid51 which influences mitochondrial fission. We will also demonstrate roles of miRNA in regulating mitochondrial fission and chemosensitivity, and explore transcription factors which control miRNA expression. Finally, we will correlate expression of mitochondrial fission regulatory factors, miRNAs and transcription factors with chemotherapy sensitivity and prognosis of TSCC patients. This project intends to explore mechanism of mitochondrial fission in regulating chemosensitivity of TSCC cells at transcription and post-transcription level, and will provide potential therapeutic targets to enhance the chemosensitivity in tongue squamous cell carcinoma.

增强化疗敏感性是提高中晚期舌鳞癌综合治疗疗效的重要因素，目前仍未取得重大进展。近年研究发现线粒体分裂介导的细胞凋亡在多种疾病中具有重要作用，但在恶性肿瘤化疗敏感性中的作用和机制尚不清楚。我们预实验发现顺铂可通过诱导舌鳞癌细胞线粒体分裂引起细胞凋亡，线粒体分裂调控因子可以介导舌鳞癌顺铂敏感性，而且其表达存在转录后调控。结合前期我们在miRNA调控舌鳞癌细胞生物学特性方面的研究基础，本课题将以miRNA作为切入点，研究其对线粒体分裂调控因子Drp1及其受体分子Fis1、Mff、Mid49/Mid51的靶向调控作用，及其对线粒体分裂和舌鳞癌顺铂敏感性的影响，并探寻miRNA的上游调控转录因子，同时结合组织样本和患者临床资料分析其临床意义。本课题将从转录水平和转录后调控水平阐明舌鳞癌细胞线粒体分裂对顺铂化疗敏感性的调控机制，为提高顺铂化疗敏感性的研究提供新思路，为今后相关药物研发提供潜在新靶点。

既往众多耐药机制的发现并未使得临床克服顺铂耐药取得实质性进展，因而重新反思顺铂诱导凋亡的本源机制可能更具现实意义。近年研究证实线粒体分裂诱导的凋亡在多种疾病中具有重要作用，但在顺铂化疗敏感性中的作用和机制尚不清楚。本研究我们发现顺铂可通过诱导舌鳞癌细胞线粒体分裂继而引起细胞凋亡，而线粒体分裂调控因子MFF和FIS1可介导舌鳞癌顺铂化疗敏感性同时其表达存在转录后调控。我们进步明确线粒体分裂调控因子MFF和FIS1对舌鳞癌顺铂化疗敏感性的确切作用；我们发现miR-483-5p可靶向调控FIS1，miR-593-5p可靶向调控MFF且其转录水平受BRCA1的调控。进一步动物实验证实了miR-483-5p-FIS1和BRCA1-miR-593-5p-MFF轴可调控舌鳞癌顺铂化疗敏感性。临床样本进一步证实miR-483-5p-FIS1和BRCA1-miR-593-5p-MFF轴可调控舌鳞癌顺铂化疗敏感性。本课题从转录以及转录后调控水平阐明线粒体分裂诱导细胞凋亡的机制及其对顺铂化疗敏感性的作用，将为临床提高舌鳞癌顺铂化疗敏感性提供新思路和更为有效的靶标。