Construction of scFv-psm-ETA recombinant immunotoxin and its antitumor effect on human prostate cancer cells in vitro and in vivo / 中华泌尿外科杂志

ABSTRACT

Objective To evaluate the construction of scFv-psm-ETA immunotoxin and to study its antitumor effect on human prostate cancer cells. Methods The genes encoding the heavy and light chain Fv regions of the monoclonal murine antibody Ed-5,which recognizes prostate specific membrane antigen on the surface of human prostate cell,were cloned by PCR technique and were used to generate single-chain immunotoxins containing Pseudomonas exotoxin A(ETA).The light and heavy chains were connected by a flexible linker to form a single-chain antigen-binding protein,which was in turn fused to truncated forms of ETA.The resulting plasmid,pSW200-psm,was transformed intoE.coli CC118 and the recombinant immunotoxins,scFv-psm-ETA,were expressed and purified to near homogeneity.The cell killing activity and in vivo antitumor activity of scFv-psm-ETA were tested using human prostate cancer cell line LNCaP. Results scFv-psm-ETA was shown to be cytotoxic specifically to 80% of LNCaP cells,which expressed the PSM on their surface at a dose up to 100 ng/ml.In athymic nude mice, administration of the scFv-psm-ETA inhibited the growth of human prostate cancer cells LNCaP.The size of the tumors was 153 mm3 and 272 mm3,respectively, in treatment group and control group (P