卵巢癌中基因损伤和PD-L1表达之间的关系研究

Study on the Relationship Between Gene Damage and PD-L1 Expression in Ovarian Cancer

目的本研究拟证明卵巢癌细胞基因修复功能损伤的程度和程序性死亡配体-1(Programmed death ligand-1,PD-L1)之间的关系,为PD-L1治疗卵巢癌提供依据。方法采用卵巢癌组织芯片(tissue microarray,TMA)样本,非小细胞肺癌TMA为对照。采用辅助损伤修复检测(repair assisted damage detection,RADD)法和改良的RADD法检测DNA损伤及修复功能缺陷水平。应用免疫组化方法观察卵巢肿瘤细胞中DNA损伤和PD-L1蛋白表达,采用激光共聚焦显微镜对TMAs内的每个组织核芯进行成像并行图像采集。记录每个核芯的荧光强度,绘制图像并计算二者的相关性。结果RADD法和改良RADD法都能有效的检测出肿瘤组织中的DNA损伤水平,其中改良的RADD(mRADD)法检出水平更高。卵巢肿瘤中DNA氧化损伤的发生率很高。随着DNA氧化损伤水平增加,PD-L1在肿瘤中的表达也随之增加。与正常组织相比,高级别浆液性腺癌和子宫内膜样腺癌的DNA损伤水平差异最明显。而且PD-L1表达和DNA损伤水平有很好的相关性。相关性分析发现,采用改良RADD法检测高级别浆液性癌和子宫内膜样腺癌的DNA损伤水平与PD-L1之间都具有良好的相关性。卵巢粘液性腺癌中的DNA损伤水平与PD-L1表达的相关性最高。结论卵巢癌DNA氧化损伤或其与PD-L1协同表达关系可能是改善PD-L1阻断治疗有效性分类筛选中的一个潜在生物标志物。

Objective This study aims to prove the relationship between the degree of damage of gene repair function of ovarian cancer cells and PD-L1,and provide evidence for the treatment of ovarian cancer with PD-L1.Methods Tissue microarray(TMA)samples of ovarian cancer and TMA of non-small cell lung cancer were used as controls.Repair assisted damage detection(RADD)and modified RADD were used to detect DNA damage and repair function deficits.DNA damage and PD-L1 protein expression in ovarian tumor cells were observed by immunohistochemistry.Confocal laser microscopy was used to image each tissue core in TMAs.The fluorescence intensity of each core was recorded,the image was plotted and the correlation between the two was calculated.Results Both RADD method and modified RADD method could effectively detect the level of DNA damage in tumor tissues,and the modified RADD(mRADD)method had a higher detection level.There was a high incidence of oxidative DNA damage in ovarian tumors.As the level of oxidative damage to DNA increased,the expression of PD-L1 in tumors also increased.The difference in DNA damage levels between high-grade serous adenocarcinoma and endometrioid adenocarcinoma was most pronounced compared to normal tissue.Moreover,the expression of PD-L1 had a good correlation with the level of DNA damage.Correlation analysis showed that the DNA damage level of high-grade serous carcinoma and endometrioid adenocarcinoma detected by modified RADD method had a good correlation with PD-L1.The level of DNA damage in mucinous ovarian adenocarcinoma had the highest correlation with PD-L1 expression.Conclusion Oxidative damage of ovarian cancer DNA or its co-expression with PD-L1 may be a potential biomarker for improving the classification of efficacy of PD-L1 blocking therapy.