Evaluation of the preventive and therapeutic effects of a recombinant vector co-expressing prostate-specific stem cell antigen and Clostridium perfringens enterotoxin on prostate cancer in rats

The effects of Clostridium perfringens enterotoxin (CPE) and prostate stem cell antigen (PSCA) on cancer prevention or treatment have been previously studied separately. For the first time, here we have elaborated a recombinant vector to co-express and study the cumulative effects of both of these factors on prostate cancer (PCa) in an animal model. The recombinant pBudCE4.1-cpe-PSCA vector was constructed in large scale. Rats were vaccinated by vector or vector plus chitosan nanoparticles before or after induction of PCa (preventive or therapeutic studies) by N-methyl N-nitrosurea and testosterone. Prostate tumors were weighed and histologically examined. Tumors and infusion site tissues as well as blood samples of all rats were collected and assessed by serological and molecular tests. We showed that vaccination with vector (along with or without nanoparticles) led to lower PCa incidence and tumor weight. The L-1β, IL6, and TNF-α serum levels and their gene expression accompanied by C-CAM1 gene expression in vaccinated groups were significantly higher than controls while no difference was seen in CK20 expression among all groups. Our findings showed that vector could effectively stimulate the immune system of rats to either prevent or suppress the PCa tumors. Adding chitosan nanoparticles did not affect the results significantly.