抗胃癌MG7单链抗体与重组超抗原SEB融合蛋白在体内外对胃癌细胞的杀伤作用研究

目的 研究SEB-scFv融合蛋白对胃癌的抑制作用.方法 在体外通过MTT法观察SEB-scFv融合蛋白对人胃癌细胞的增殖抑制作用;DNA ladder法观察融合蛋白对胃癌细胞凋亡的影响;在电子显微镜下观察融合蛋白处理后胃癌细胞的形态变化;流式细胞仪分析胃癌细胞凋亡率.采用胃癌动物模型观察治疗后肿瘤重量和存活时间.结果 胃癌细胞的增殖抑制率随SEB-scFv融合蛋白作用浓度的增加而逐渐增大,且对不表达MG7相关抗原的肿瘤细胞不表现杀伤效应;1.0μg/ml和10μg/ml高浓度融合蛋白组DNA凝胶电泳呈现明显的梯状条带;在电子显微镜下可观察到被融合蛋白活化的免疫效应细胞攻击后的胃癌细胞表现出典型的凋亡特征性变化;融合蛋白0.1μg/ml、1.0μg/ml、10μg/ml组细胞G0/G1期前有明显的凋亡峰出现,三者的凋亡率分别达到51.62%、54.21%和61.55%,而生理盐水组凋亡率仅为1.44%,差异具有统计学意义(P＜0.05).融合蛋白治疗组大鼠移植瘤的瘤重明显低于其他各组(P＜0.05),抑瘤率高达61.3%,其生存时间为(31.7±2.1)d,存活时间延长达54.6%.结论 SEB-scFv融合蛋白作为一种新的抗肿瘤生物制剂有明显的抑癌效应.

Inhibitive effect of SEB-scFv fusion protein on gastric cancer

Objective To evaluate the antitumor effect of SEB-scFv fusion Drotein on gastric cancer. Methods Typical changes of morphologic features and super-microstructure were observed when SEB-scFv fusion protein was used in SGC7901 cens;and the effects of SEB-scFv and its concentration on the cell growth were examined by methyltetrazolium(MTT)assay;DNA ladder and flow cytometry were employed respectively to detect the inhibition phenomenon or apoptosis.We produced a subcutaneous gastric tumor model in baby SD rats by implanting SGC7901 cells.The SEB and SEB-scFv were injeeted to the vena caudalis in the trial groups,and normal saline to the control group.The weight of the tumor and the survival were recorded after treatment. Results Cell inhibitory rate was increased along with increased concentration of SEB-scFv fusion protein.Electron microscopy revealed that the cell presented typical changes of apoptosis.FCM indicated that the apoptotic rate of SGC7901 cell lines significantly increased with increasing dose of SEB-scFv fusion protein,and agarose gel electrophoresis appeared marked DNA ladder.The average weight of tumor in the SEB-scFv group was lower than that in control groups(P＜0.05).The tumor inhibition rate was 61.3%,and the mean survival period of rats in SEB-scFv group was longer than that of other group(P＜0.05)with a survival prolongation rate of 54.6%. Conclusion The resuhs indicate that SEB-scFv fusion protein has an obvious antitumor effect on gastric cancer.