ELK1转录激活PD-L1表达对结直肠癌细胞增殖及侵袭影响  

Transcriptional activation of PD-L1 by ELK1 contributes to the proliferation and migration of colorectal carcinoma cancer cells

作　　者：侯倩倩[1] 杨芳[1] 王大庆[1] 肖杨[1] 赵鹏[2] 石庆芳[1] HOU Qian-qian;YANG Fang;WANG Da-qing;XIAO Yang;ZHAO Peng;SHI Qing-fang(Hengshui Harrison International Peace Hospital,Hengshui 053000,P.R.China)

机构地区：[1]衡水市哈励逊国际和平医院肿瘤内科,河北衡水053000 [2]衡水市哈励逊国际和平医院放射科,河北衡水053000

出　　处：《中华肿瘤防治杂志》2020年第2期122-129,共8页Chinese Journal of Cancer Prevention and Treatment

基　　金：河北省衡水市科技局立项课题（15011）

摘　　要：目的含ETS域转录因子Elk1(ETS transcription factor Elk1,ELK1)作为原癌基因,具体分子作用机制仍不清楚。本研究探讨结直肠癌中ELK1与程序性死亡因子配体1(programmed death-ligand 1,PD-L1)表达相关性以及二者在促进结直肠癌细胞增殖中的作用及其机制。方法应用免疫组织化学染色方法检测ELK1与PD-L1在衡水市哈励逊国际和平医院病理科2017-03-02-2018-12-26收集87例结直肠癌及其癌旁正常黏膜组织中的表达。利用慢病毒转染技术对SW480细胞进行ELK1基因过表达,通过CCK8、Transwell小室和蛋白质印迹法检测在过表达ELK1基因前后SW480细胞系的增殖、侵袭和PD-L1表达水平的变化,采用双荧光素酶报告基因和染色质沉淀RT-qPCR实验验证ELK1是否直接通过ELK1基序结合到PD-L1的基因启动子区。结果ELK1在结直肠癌组织中的阳性表达率(75.86%,66/87)高于癌旁黏膜组织(12.64%,11/87),差异有统计学意义,χ^2=80.352,P<0.001。PD-L1在结直肠癌组织中的阳性表达率(59.77%,52/87)高于癌旁黏膜组织(3.45%,3/87),差异有统计学意义,χ^2=75.287,P<0.001。ELK1和PD-L1蛋白表达均与患者的性别、年龄和肿瘤部位无关联,P>0.05;而与其肿瘤分化程度、浸润深度和有无淋巴结转移有关联,χ^2值分别为43.152、24.671和23.104,均P<0.001。ELK和PD-L1表达水平呈高度正相关,r=0.967,P<0.001。与空白对照组相比,ELK1过表达组细胞的增殖、侵袭和PD-L1表达均升高。ELK1干扰组细胞的增殖、侵袭和PD-L1表达均降低;双荧光素酶报告基因和染色质沉淀RT-qPCR实验研究结果表明,ELK1可直接结合在PD-L1启动子上。结论 ELK1可转录激活PD-L1表达,从而促进结直肠癌细胞增殖及侵袭。OBJECTIVE To investigate the expression,function and the relationship between ELK1 and PD-L1(programmed death-ligand-1,PD-L1)in colorectal carcinoma.METHODS ELK1 and PD-L1 protein expression were detected in 87 cases of colorectal carcinoma tissues compared with the adjacent normal mucosa by immunohistochemistry assay.Lentivirus-mediated recombination ELK1 was transfected into SW480 cells.The cell proliferation and migration were detected by CCK8 assay and Transwell assay,respectively.Western Blot was used to detect the expression of PD-L1.Dual luciferase reporter gene assays and chromatin immunoprecipitation RT-qPCR assays were used to verify the interaction between ELK1 and PD-L1.RESULTS The expression of ELK1 in colorectal carcinoma tissues(75.86%,66/87)was higher than that in normal adjacent mucosa tissues(12.64%,11/87;χ^2=80.352,P<0.001).The expression of PD-L1 in colorectal carcinoma tissues(59.77%,52/87)was higher than that in normal adjacent mucosa tissues(3.45%,3/87;χ^2=75.287,P<0.001).The expression of ELK1 and PD-L1 protein was independent from tumor location,patient’s gender and age(P>0.05);but it was associated with tumor differentiation degree,invasion depth and lymph node metastasis(χ^2 values were 43.152,24.671 and 23.104,and P<0.001).The level of ELK1 was positively correlated with the level of PD-L1 protein(r=0.967,P<0.001).The proliferation and migration of SW480 cells in ELK1 over-expressed SW480 cells were increased as compared with control group(P<0.05),and the protein expression level of PD-L1 in ELK1 overexpressed SW480 cells were increased(P<0.05).On the contrary,ELK1 knockdown expression in SW480 cells decreased their proliferation,migration and PD-L1 expression.Dual luciferase reporter gene assays and chromatin immunoprecipitation RT-qPCR assays showed that PD-L1 was a direct transcriptional target of ELK1.CONCLUSION ELK1 transcriptionally upregulated PD-L1,thus enhancing colorectal carcinoma cancer cells proliferation and migration.

关 键 词：结直肠癌 含ETS域转录因子Elk1 程序死亡配体-1 转录激活 增殖及侵袭 

分 类 号：R735.3[医药卫生—肿瘤]