目的： 表达并纯化转化生长因子α与绿脓杆菌外毒素融合蛋白（TGFα-PE40），探讨其对EGF受体（EGFR）阳性肿瘤细胞的靶向杀伤作用。方法：用pET28a表达载体构建表达TGFα-PE40蛋白的重组体pV28，IPTG诱导其表达后，提取包涵体蛋白并用Ni柱纯化，MTT法观察复性融合蛋白对肿瘤细胞A431和SK-OV3的杀伤效用。结果：成功构建基因重组质粒pV28，纯化后的包涵体蛋白中TGFα-PE40蛋白纯度达98％以上，这种活性毒素蛋白对EGFR高表达的A431癌细胞抑制率为50％（IC50）时所需蛋白浓度为(0.86±0.07)μg/ml，低于EGFR低表达的SK-OV3癌细胞的IC50 (6.37±2.18μg/ml)，差异显著（P<0.05）。结论： 融合蛋白 TGFα-PE40 对肿瘤细胞的毒性与肿瘤细胞表面表达的EGFR数量成正相关，可选择性杀伤肿瘤细胞。

Objective：To express and purify transforming growth factor α (TGFα)-pseudomonas exotoxin 40 and investigate its cytotoxic effect on cancer cells overexpressing epidermal growth factor (EGF) receptor. Methods：Recombinant plasmid pV28 was constructed by inserting the gene coding TGFα-PE40 into the vector pET28a Expression of fusion protein was conducted using the host BL21. Production of the recombinant protein was induced by IPTG, following extraction and purification of inclusion bodies with His-tag purification system. Cell viability assay (by MTT) was performed to determine the cytotoxic effect of TGFα-PE40 on cancer cells (A431 and SK-OV3).Results：Recombinant plasmid pV28, which expresses TGFα-PE40, was constructed successfully. Purity of TGFα-PE40 was about 98% after a purification procedure using His-tag column. Cytotoxic experiment showed that at a concentration of 0.86±0.07 μg/ml, TGFα-PE40 could reduce 50% viability of A431, which has high expression of EGFR. Whereas the IC50 for ovarian cancer cell SK-OV3, which expresses less EGFR, was 6.37±2.18 μg/ml.There was a significant difference between these two groups (P<0.05). Conclusion：The cytotoxicity ability of the fusion protein on tumor cells depends on the number of the EGFR presented on tumor cells.

国家自然科学基金（30171507）