Abstract: This work aims to conduct the prokaryotic expression and purification of a novel recombinant toxin rCCK_96-104PE38,and to verify the targeted killing effect on colon cancer cells. A reversed cholecystokinin（rCCK_96-104）was conjunct to pseudomonas exotoxin（PE38）by gene amplified technology to construct a prokaryotic expression vector. Ni-NTA affinity chromatograph was used for purification. The anti-tumor ability of rCCK_96-104PE38 was verified by in vitro cytotoxicity of colon cancer cells and vivo experiment with nude mice model. Results showed that the amplified gene of rCCK_96-104PE38 was in correct sequence as designed,i.e.,the active expression was successfully achieved using prokaryotic expression system of pET-28a. The purified recombinant protein induced the apoptosis of colon cancer cells in vitro,and inhibited the tumor growth in nude mice model. Conclusively,it was successful to produce the recombinant toxin rCCK_96-104PE38 in high purity and with no tags,the vitro and vivo experiments confirmed that it had inhibitory ability on colon cancer.

Key words: recombinant toxin, colon cancer, cholecystokinin, pseudomonas exotoxin