lnc-POP1-1通过调控MCM5蛋白DNA修复活性增强口腔鳞癌细胞顺铂耐药的机制

DNA损伤修复导致的顺铂耐药是口腔鳞癌化疗失败的主要原因之一，而长链非编码RNA（lncRNA）在DNA损伤修复中的作用尚不明确。申请人前期从口腔鳞癌顺铂耐药细胞中筛选出表达上调但功能未知的核内lncRNA lnc-POP1-1；发现其与口腔鳞癌细胞顺铂耐药有关，并参与调控DNA损伤修复途径；进一步发现lnc-POP1-1与DNA修复相关蛋白MCM5结合，调控MCM5蛋白的表达。据此我们推测：lnc-POP1-1通过与MCM5蛋白相互作用调控MCM5蛋白稳定性和DNA修复活性来增强口腔鳞癌细胞顺铂耐药性。本项目拟通过CRISPR/Cas9、RNA pull-down、RIP、Co-IP等方法，从临床样本检测、实验动物学及分子生物学等层面系统阐述lnc-POP1-1调控口腔鳞癌顺铂耐药的具体机制。这将丰富我们对口腔鳞癌顺铂耐药的认知，同时为临床寻找顺铂耐药预测标记和逆转靶点提供新的研究基础。

Cisplatin resistance caused by DNA damage repair is one of the main reasons for the chemotherapy failure of oral squamous cell carcinoma (OSCC), and the role of long noncoding RNA (lncRNA) in DNA damage repair is still unclear. In our recent studies, the applicant screened a novel lncRNA named lnc-POP1-1 which was mostly localized in the nucleus and was upregulated in cisplatin-resistant OSCC cells, however, the function of lnc-POP1-1 was unknown. Our preliminary experiments found that lnc-POP1-1 was related to cisplatin resistance of OSCC cells and participated in DNA damage repair pathways. Furthermore, lnc-POP1-1 could bind to Minichromosome maintenance proteins 5 (MCM5) which was a DNA repair-related protein to upregulate the protein expression of MCM5. Based on the results of preliminary experiments, we propose the hypothesis that lnc-POP1-1 enhances cisplatin resistance of OSCC cells by interacting with MCM5 and regulating the stability and DNA repair activity of MCM5 protein. The purpose of this project is to systematically study the effect of lnc-POP1-1 on cisplatin resistance of OSCC from clinical tissue specimens, experimental zoology and molecular biology, and to clarify the mechanism of lnc-POP1-1 participating in DNA damage repair by the methods of CRISPR/Cas9 system, RNA pull-down, RNA Binding Protein Immunoprecipitation (RIP), Co-Immunoprecipitation (Co-IP), etc. This study will enrich the understanding of cisplatin resistance in OSCC, which provides a new experimental basis for identifying the predictive biomarkers and the reversed therapeutic targets for cisplatin resistance.