B7H1在胰腺癌panc-1细胞的表达及其功能研究

目的:探讨胰腺癌细胞株panc-1中B7同源物1(B7H1)的表达及其对T细胞增殖活化的调节作用。方法:分别应用RT-PCR和流式细胞术检测B7H1在γ-干扰素(IFN-γ)处理或B7H1小干扰RNA(siRNA)转染前后panc-1细胞中的表达。采用植物血凝素(PHA)刺激人外周血T细胞体外增殖,加入IFN-γ处理或B7H1-siRNA转染前后panc-1细胞混合培养72 h,四甲基偶氮唑盐(MTT)比色法检测T细胞的增殖,用酶联免疫吸附法(ELISA)检测共培养上清中的IFN-γ、白细胞介素-2(IL-2)和白细胞介素-10(IL-10)的分泌。结果:panc-1细胞组成性表达B7H1。IFN-γ处理可以显著上调B7H1表达,抑制共培养T细胞的增殖和IFN-γ、IL-2分泌,但是促进IL-10的分泌。相反,应用B7H1-siRNA阻断B7H1表达后则显著促进T细胞增殖和IFN-γ、IL-2的分泌,但下调IL-10的分泌。结论:B7H1分子在体外通过抑制T细胞增殖和Th1类细胞因子分泌来下调T细胞功能。应用siRNA技术阻断B7H1有望成为治疗胰腺癌的新途径。

Functional expression of B7H1 on pancreatic carcinoma panc-1 cells

AIM: To observe the effect of B7H1 expression in pancreatic carcinoma cells on the proliferation and activation of co-cultured T lymphocytes. METHODS: B7H1 expression in panc-1 cells before and after interferon-γ(IFN-γ) treatment or B7H1-siRNA transfection was evaluated by RT-PCR and flow cytometry. The influence of B7H1 expression on co-cultured PHA-activated T lymphocytes was determined by the methods of MTT and enzyme-linked immunosorbent assay (ELISA). RESULTS: B7H1 was highly expressed in panc-1 cells and up-regulated after IFN-γ stimulation. Such up-regulation led to the significant inhibition of T cell proliferation and secretion of cytokines such as IFN-γ and interleukin-2(IL-2). However, IL-10 production was enhanced. In contrast, knockdown of B7H1 expression in panc-1 cells by RNA interference resulted in increased T cell proliferation as well as IFN-γ and IL-2 production. Meanwhile, the IL-10 secretion decreased. CONCLUSION: B7H1-expressing panc-1 cells suppress T cell function by inhibiting T cell proliferation and production of Th1 cytokines. Suppression of B7H1 expression through siRNA restores T cell immune functions, indicating a potential strategy for immunotherapy against pancreatic cancer.