FasL、B7-1联合基因修饰的胃癌细胞诱导抗胃癌主动免疫的研究

Active immunity of anti-gastric cancer induced by FasL and B7-1 gene modified tumor cells

目的 探讨FasL、B7-1联合基因转移是否具有协同的抗肿瘤效应。方法 采用重组腺病毒载体将FasL、B7-1基因导入人胃癌细胞SGC-7901,G418阳性克隆筛选,流式细胞分析,逆转录-聚合酶链反应(RT-PCR),显示FasL和B7-1的表达,并且通过Hoechst33342染色检测胃癌细胞凋亡;将携带 FasL和 B7-1基因的胃癌细胞(命名为 SGC-7901/FB-11)接种于 C57BL/6小鼠背部皮下,观测其致瘤性能;SGC-7901/FB-11致敏的小鼠对野生型瘤细胞是否具有免疫保护作用;用SGC-7901和 SGC-7901/FB-11细胞分别经腹腔免疫小鼠,得到腹腔浸润淋巴细胞及致敏脾细胞,MTT法检测其体外杀伤实验。结果 FasL和B7-1基因在胃癌细胞中获得高表达并可诱导胃癌细胞的凋亡,双基因转染的胃癌细胞的致瘤性明显下降;SGC-7901/FB-11诱导的细胞毒T淋巴细胞(CTL)对SGC-7901的杀伤活性显著高于野生型SGC-7901诱导的CTL对相同靶细胞的杀伤活性(P<0.05);SGC-7901/FB-11诱导的 CTL对 SGC-7901/FB-11的杀伤率显著高于对野生型 SGC-7901的杀伤率(P<0.05)。结论 FasL促进胃癌细胞凋亡,B7-1促进抗胃癌CTL的增殖、活化,在效应阶段两基因发挥着重要的协同作用。

Objective To study the activation of CTLs against gastric cancer cells induced by FasL and B7-1 gene modified tumor cells and to explore whether co-expression of FasL and B7-1 in SGC- 7901 tumor cells could initiate an synergistic antitumor effect. Methods FasL and B7-1 genes were transfected into human gastric cancer SGC-7901 cells mediated with adenovirus. The positive clones were selected by G418. The flow cytometry and RT-PCR were used for detection of the FasL and B7-1 expres- sion. FasL + /B7-1 + SGC-7901 (SGC-7901/FB-11) cells were inoculated into the back of C57BL/6 mice subcutaneously for observation of their tumorigenicity. The SGC-7901/FB-11 cell sensitized mice obtained the protective immune activity against the rechanllenge of wild type SGC-7901 cells. The ab- dominal infiltrating lymphocytes and sensitized spleen cells were obtained from the mice immunized with SGC-7901/FB-11 or wild type SGC-7901 cells intraperitoneally, and the cytotoxicity of these CTLs a- gainst tumor cells was detected by MTT assay. Results FasL and B7-1 genes were highly expressed in gastric cancer cells and could induce the apoptosis of gastric cancer cells. The gastric cancer cells with transfection of FasL and B7-1 genes had a significantly decreased tumorigenicity. The cytotoxicity of CTL induced by SGC-7901/FB-11 against SGC-7901 was significantly higher than that by wild SGC-7901 a- gainst the same target cells (P < 0.05). Conclusion The FasL and B7-1 can effectively promote the ac- tivity of CTL against gastric cancer cells. FasL/B7-1 molecules play an important role in CTL cytotoxicity function as well. After introduced into SGC-7901 cells, Ad-B7-1 shows enhanced therapeutic efficiency for SGC-7901 cells when combined with Ad-FasL.