下调同源重组分子MUS81对上皮性卵巢癌化疗的增敏作用及其机制研究

Chemotherapy with platinum metallic antitumor drugs after sugery is a necessary and complementary treatment in epithiel ovarian cancer (EOC) . Homologous recombination (HR), a unique mode of the repair of impaired dsDNA, activities of which elevated extremely in EOC, has a direct impact on the sensitivity of platinum-containing drugs chemohtherapy. Our preliminary experiment indicated that MUS81 is the pivotal molecule involved in regulating HR; when EOC cells were treated with platinum-containing drugs, DNA repair and synthesis was decreased remarkably after the expression of MUS81 was downregulated, and the proliferation of the transduced cells was reduced and the growth was inhibited significantly, which indicated that the downregualtion of MUS81 can improve the sensitivity of chemotherapy. However, the mechanisms are still unclear. Thus, we will use tissue experiments to identify the mechanisms of the genome instability regulated by MUS81 and explore its relationship with outcomes of clinical treatment; we will upregulate or downregulate MUS81 to analyze the biological effects such as the changes of cell cycle and apoptosis; we will use the techniques such as transcriptional profile analysis and interaction protein screening array, etc. to explore molecular network and pathway of DNA repair regulated by MUS81, and to elucidate the melocular mechanisms in the cell proliferation and the sensitivity of drugs; we also will use the in vivo experiments to validate the differences in volume of the mass and metastasis of tumor with chemotherapeutic drugs when MUS81 is decreased. The project is helpful to reveal the mechanisms that the downregualtion of MUS81 can promote the sensitization to chemotherapy in EOC, which lay a foundation on improving the clinical EOC management.

铂类化疗是上皮性卵巢癌(EOC) 术后重要的治疗手段。同源重组(HR)是受损双链DNA的主要修复方式，在EOC中异常活跃，直接影响铂类化疗敏感性。本课题预实验发现，MUS81是调控HR的关键分子；铂类药物作用下，EOC细胞经MUS81表达下调后其DNA修复与合成、细胞增殖、生长能力均显著降低，提示MUS81下调可增加化疗敏感性，相关机制尚不清楚。本课题拟通过组织学实验，探索MUS81参与基因组不稳定的调节机制，分析MUS81与临床疗效的关系；通过细胞水平上/下调MUS81，观察细胞周期、凋亡等生物学改变，采用细胞基因表达谱分析、蛋白芯片等技术揭示MUS81参与DNA修复的分子网络与通路，阐明其调节细胞周期、药物敏感的分子机制；通过体内实验验证MUS81下调对铂类药物引起肿瘤缩小及转移的差异。本研究有助于揭示下调MUS81提高EOC化疗敏感性的机制，对于指导临床EOC化疗具有实际应用价值。

铂类化疗是上皮性卵巢癌(EOC) 术后重要的治疗手段。同源重组(HR)是受损双链DNA的主要修复方式，在EOC中异常活跃，直接影响铂类化疗敏感性。本课题预实验发现，MUS81是调控HR的关键分子；铂类药物作用下，EOC细胞经MUS81表达下调后其DNA修复与合成、细胞增殖、生长能力均显著降低，提示MUS81下调可增加化疗敏感性，相关机制尚不清楚。.本课题拟通过组织学实验，探索MUS81参与基因组不稳定的调节机制，分析MUS81与临床疗效的关系；通过细胞水平上/下调MUS81，观察细胞周期、凋亡等生物学改变，采用细胞基因表达谱分析、蛋白芯片等技术揭示MUS81参与DNA修复的分子网络与通路，阐明其调节细胞周期、药物敏感的分子机制；通过体内实验验证MUS81下调对铂类药物引起肿瘤缩小及转移的差异。通过四年系统研究，项目组发现MUS81在EOC中高表达且与疾病进展高度相关，是EOC全新的预后预测分子；通过系统的体内、外模型探索明确MUS81表达有助于稳定EOC基因组，维持细胞生存；证实MUS81直接参与EOC对包括奥拉帕尼、CPT等在内多种化疗药物的耐受过程，是驱动EOC化疗耐受的全新关键分子。进一步机制探索从多角度、多层面解析了MUS81促进EOC化疗耐受的分子机制；描绘了MUS81下游多种作用途径：CHK1/CyclinB信号、Rad51、BM28、以及MCM2，全面阐述了MUS81发挥作用的机制，为临床个体化治疗奠定基础。此外，通过构建体外细胞模型与体内皮下移植瘤模型，系统测试了下调MUS81策略对于EOC化疗敏感性的作用；运用大量实验数据证实下调MUS81表达可有效克服EOC对奥拉帕尼、CPT等药物的耐受，增强其疗效。本项目研究成果望为临床个体化治疗奠定基础。这一新型分子干预手段有望切实提高EOC患者的疗效，对提高我国EOC治疗水平有积极而深远的意义。