Study On Fusion Immunotoxin Targeting Colorectal Cancer

In order to improve the recombinant immunotoxin(IT)of colorectal cancer targeted therapy,a novel recombinant immunotoxin(IT)with high safty and efficiency was successfully prepared by recombinant fusion of anti-CEA(serum carcinoembryonic antigen,CEA)nanobody and PE(Pseudomonas aeruginosa exotoxin,PE).Our work laid a foundation for a potential application of the recombinant IT for colorectal cancer targeting therapy.In this work,an anti-CEA nanobody(11C12)with high specificity and affinity was preapard and screened,and then a fusion expression vector of 11C12 with structural engineered PE toxin(PE40)was successfully constructed,named as pET28a-11C12/PE40.Based on the construct of pET28a-11C12/PE40,a expression vector of PE/11C12 fusion proteins and a protective nanobody against PE toxin was also constructed for studing its protective effects,named as pET28a-11C12/PE40/2F2.The recombinant fusion proteins were expressed in E.coli system and purified.LoVo and SW480 that expressing CEA as well as human normal colonic epithelial cell that has no CEA expression were tested.The study showed that both of the rocombiant ITs had significant inhibitory effect on colorectal cancer cells expressing CEA.Cytotoxocity,effect of PE/11C12 fusion protein was also observed in normal human colonic epithelial 2950 cells,protective effect was observed for the protective IT fusion protein.Our study offered a novel,safe and efficient solution for coloreactal therapy.