circularCUX1在肝癌细胞程序性死亡因子1配体耐药机制中的作用研究

Study on the role of circularCUX1 in the mechanism of drug resistance mediated by programmed death factor 1 ligand in hepatocellular carcinoma cells

目的:探究circularCUX1(circCUX1)对肝癌细胞免疫逃逸的作用及其相关机制。方法;收集45例肝癌切除肿瘤组织,qRT-PCR检测肿瘤组织程序性死亡因子1配体(PD-L1)的表达水平,circRNA-seq分析PD-L1高表达和低表达肿瘤组织中circRNA的差异表达,并比较circCUX1与PD-L1表达的相关性。在细胞实验中采用qRT-PCR和Western blot检测HCCLM3、HepG2、SMMC-7721细胞circCUX1和PD-L1的表达水平,通过NK细胞毒性实验检测对NK细胞的敏感性。将HCCLM3细胞分为si-NC组(转染si-NC)和si-circCUX1组(转染si-circCUX1),检测两组细胞circCUX1和PD-L1的表达水平以及对NK细胞的敏感性。结果:在肝癌患者肿瘤组织中,与PD-L1低表达肿瘤组织比较,PD-L1高表达肿瘤组织有282个circRNA表达上调,307个circRNA表达下调,其中circCUX1与PD-L1的表达水平呈正相关(R=0.6289,P<0.05)。与HepG2细胞和SMMC-7721细胞比较,HCCLM3细胞中circCUX1的表达水平升高(P<0.05),PD-L1 mRNA和蛋白的表达水平升高(P<0.05),其对NK细胞的敏感性降低(P<0.05)。与si-NC组比较,circCUX1组circCUX1的表达水平降低(P<0.05),PD-L1 mRNA和蛋白的表达水平降低(P<0.05),其对NK细胞的敏感性增加(P<0.05)。结论:在肝癌组织中circCUX1与PD-L1的表达呈正相关,circCUX1通过影响PD-L1表达介导肝癌细胞的免疫逃逸。

Objective: To explore the effect of circularCUX1(circCUX1)on the immune escape of hepatocellular carcinoma cells and its related mechanism.Methods: Forty-five cases of hepatocellular carcinoma resected tumor tissues were collected,and the expression level of programmed death factor 1 ligand(PD-L1)in tumor tissues was detected by qRT-PCR.circRNA-seq was used to analyze the circRNA expression difference between the high and low expression of PD-L1,and the correlation between circCUX1 and PD-L1 expression was compared.In cell experiments,the expression levels of circCUX1 and PD-L1 in HCCLM3,HepG2 and SMMC-7721 cells were detected by qRT-PCR and Western blot,and the sensitivity to NK cells was detected by NK cell toxicity assay.HCCLM3 cells were divided into si-NC group(transfected with si-NC)and si-circCUX1 group(transfected with si-circCUX1),and the expression levels of circCUX1 and PD-L1 and their sensitivity to NK cells were detected.Results: In tumor tissues of hepatocellular carcinoma patients,compared with tumor tissues with low PD-L1 expression,282 circRNA with high PD-L1 expression were up-regulated and 307 circRNA were down-regulated,among which circCUX1 was positively correlated with PD-L1 expression level(R=0.6289,P<0.05).Compared with HepG2 cells and SMMC-7721 cells,the expression level of circCUX1 and the mRNA and protein expression of PD-L1 in HCCLM3 cells increased(P<0.05),the sensitivity of HCCLM3 cells to NK cells decreased(P<0.05).Compared with si-NC group,circCUX1 group had lower circCUX1 expression(P<0.05),lower PD-L1 mRNA and protein expression(P<0.05),and higher sensitivity to NK cells(P<0.05).Conclusion: circCUX1 is positively correlated with the expression of PD-L1 in hepatocellular carcinoma cells,and circCUX1 mediates the immune escape of HCC cells by affecting the expression of PD-L1.