肾细胞癌PBRM1表达缺失抑制CD8^(+)T细胞浸润

PBRM1 Deletion Inhibits CD 8^(+)T Cells Infiltration in Tumor Microenvironment of Renal Cell Carcinoma

[目的]探讨PBRM1调控CD8^(+)T在肾透明细胞癌组织中细胞浸润的分子机制。[方法]以肾透明细胞癌患者肿瘤临床标本为研究对象,探讨CD8^(+)T细胞在人肾癌中的浸润及其与临床病理特征的关系,以免疫印迹、荧光免疫、ELISA等分子生物学方法明确PBRM1调控CD8^(+)T细胞浸润的分子机制。免疫荧光检测CD63、EZH2及PHK26在细胞中的分布。免疫印迹检测IFN-γ,IL-6和TNF-α不同因子处理对肾癌细胞EZH2的诱导表达。实验结果经GraphPad Prism软件,t检验对两组间差异进行统计学分析。[结果]肾透明细胞癌组织免疫组化结果显示,在肿瘤组织中CD8^(+)T细胞浸润数量显著性下降(P<0.001),CD8^(+)T细胞浸润与患者总生存期呈正相关(P<0.001)。患者肿瘤组织PBRM1着色和CD8^(+)T细胞浸润数量结果显示:PBRM1表达与CD8^(+)T细胞浸润数量呈正相关(P<0.001)。IFN-γ,IL-6和TNF-α细胞因子促进EZH2在细胞表达升高,同时被外泌体包载被运输到受体细胞,外泌体EZH2进入受体细胞抑制CXCL9和CXCL10细胞因子分泌。[结论] PBRM1缺失激活exo-EZH2/CXCL9(10)信号轴抑制CD8^(+)T细胞肿瘤组织浸润。

[Objective] To explore the molecular mechanism of PBRM1 in regulating CD8^(+)T cell infiltration in clear cell renal cell carcinoma tissue. [Methods] The expression of PBRM1 in renal clear cell carcinoma were detected by tissue microarray and its relation with CD8^(+)T cell infiltration in tumor microenvironment was analyzed. Western blot was also applied to detect EZH2 expression after IFN-γ, IL-6 and TNF-α treatment in renal cell carcinoma cells. Immunofluorescence was used to detect the distribution of CD63, EZH2 and PHK26 in cells. The effect of EZH2 on CXCL9/10 secretion was detected by ELISA assay. The Graph Pad Prism software was used for statistical analysis. [Results] Tissue microarray results showed that the infiltration density of CD8^(+)T cells in tumor tissues was lower than that in adjacent tissues(P<0.001). High CD8^(+)T cell infiltration was positively correlated with the overall survival of patients( P < 0. 001), and low PBRM1 protein expression was associated with decreased infiltration of CD8^(+)T cells(P <0.001).IFN-γ, IL-6 and TNF-α promoted the expression of EZH2 protein, which was packaged in exosomes and entered into recipient cells to inhibit CXCL9 and CXCL10 secretion. [Conclusion]PBRM1 deletion activates the exo-EZH2/CXCL9(10) signal axis and inhibits CD8^(+)T cell tumor tissue infiltration in renal cell carcinoma.