食管鳞状细胞癌YES-2细胞顺铂耐药致其恶性生物学行为及PD-L1表达的变化

Transformation of malignant biological behaviors and PD-L1 expression in esophageal squamous cell carcinoma YES-2 cell induced by CDDP resistance

目的:探讨食管鳞状细胞癌(esophageal squamous cell carcinoma,ESCC)YES-2细胞顺铂(cis-dichlorodiammine platinum,CDDP)耐药后(YES-2/CDDP-R)细胞恶性生物学行为的变化和程序性死亡受体-配体1(programmed cell death-ligand 1,PD-L1)表达的变化。方法:用CDDP由低质量浓度到高质量浓度(0.25~2.0μg/ml)间断冲击(间隔15~25 d)的方法处理YES-2细胞,建立CDDP耐药细胞株YES-2/CDDP-R。倒置显微镜下观察YES-2/CDDP-R细胞的形态学变化,MTT法检测细胞对CDDP敏感性的变化,划痕愈合实验检测耐药前后细胞迁移能力的变化,qPCR和Western blotting检测耐药前后细胞中PD-L1 mRNA和蛋白表达水平的变化。结果:经过CDDP梯度给药9个月后成功建立YES-2/CDDP-R细胞。显微镜下见YES-2/CDDP-R细胞的形态大小不一、胞内空泡及黑色颗粒明显增多且出现巨大细胞。与YES-2细胞比较,YES-2/CDDP-R细胞的IC50值显著升高,表明其对CDDP的敏感程度降低(P<0.05);YES-2/CDDP-R细胞的增殖和迁移能力显著增强(P<0.05或P<0.01),PD-L1 mRNA和蛋白表达水平显著升高(均P<0.01)。结论:成功建立的CDDP耐药细胞株YES-2/CDDP-R对CDDP的敏感程度降低,其增殖和迁移能力增强。YES-2/CDDP-R细胞中PD-L1表达水平升高,提示CDDP耐药可能通过上调YES-2细胞PD-L1表达水平促进免疫逃逸。

Objective: To investigate the changes in malignant biological behaviors and expression of programmed cell death-ligand 1(PD-L1) in esophageal squamous cell carcinoma(ESCC) YES-2 cell line after cis-dichlorodiammine platinum(CDDP) induction(YES-2/CDDP-R). Methods: YES-2 cells were treated with CDDP from low concentration to high concentration(0.25-2.0 μg/ml) with intermittent impact(15-25 days per concentration) to establish ESCC CDDP-resistant cell line YES-2/CDDP-R. The morphological change of YES-2/CDDP-R cells was observed under the inverted microscope. Methyl thiazolyl tetrazolium(MTT) was used to detect cell sensitivity to CDDP. Wound healing assay was used to detect cell migration ability. qPCR and Western blotting were used to detect mRNA and protein expressions of PD-L1. Results: After CDDP gradient treatment for 9 months, YES-2/CDDP-R cells were successfully established. The morphology of the YES-2/CDDP-R cells showed uneven size, intracellular vacuoles and significantly increased black particles along with the appearance of huge cells. The IC50 of CDDP for YES-2/CDDP-R cells was significantly higher than that for parental cells, indicating decreased sensitivity to CDDP(P<0.05). Compared to theYES-2 cells, the proliferation and migration of YES-2/CDDP-R cells were significantly increased(P<0.05 or P<0.01), and the mRNA and protein expressions of PD-L1 were significantly up-regulated(all P<0.001). Conclusion: YES-2 cells with CDDP resistance(YES-2/CDDP-R) were successfully established.The sensitivity of YES-2/CDDP-R cells to CDDP was significantly reduced while the abilities of cell proliferation and migration were enhanced. The up-regulation of PD-L1 in YES-2/CDDP-R cells suggests that CDDP-resistance could promote immune escape by inducing PD-L1 up-regulation.