Search

To date, there is no effective therapy for hormone-independent prostate cancer. Therefore, as a new strategy for refractory cancer, gene therapy is showing increasing promise. In this study, we attempted to use a nonviral gene transfer system, in vivo electroporation, in prostate cancer cell PC-3 xenografts with the wild-type p53 (wt-p53) gene, as gene therapy for hormone-independent prostate cancer. To evaluate this in vivo gene transfer method, the beta-galactosidase gene was transfected into xenografts by electroporation. Then, the efficiency of transfection of exogenous p53 gene by electroporation was confirmed by reverse transcription-PCR, which indicated that p53 mRNA was present in samples from xenografts. Next, to estimate the reduction of prostate cancer xenografts by this method, we measured the size of PC-3 xenografts in nude mice after electroporation with the wt-p53 gene. The growth of tumors was markedly suppressed by wt-p53 gene transfection by electroporation compared with transfection of mutated type p53 gene (P = 0.0027) or vector only (P = 0.0015). Furthermore, histological specimens revealed increased apoptotic cell death in p53-transfected tumors. These results suggest that it is possible to transfer wt-p53 into prostate cancer xenografts using electroporation and to suppress the growth of tumors; they, furthermore, suggest that this system might be used for local advanced hormone-independent prostate cancer.

OBJECTIVE To investigate the antitumour effect of electroporation (EP), a drug delivery system that has been shown to be effective synergistically with antitumour drugs, with bleomycin on the growth of prostate cancer xenografts in nude mice. MATERIALS AND METHODS PC-3 cells were implanted subcutaneously into nude mice. After determination of the optimal conditions of electric pulse voltage and bleomycin dose, tumour growth in mice treated with EP plus bleomycin was compared with that in mice receiving EP alone, bleomycin alone or no treatment. In all four groups, apoptosis in the tumours was assessed. RESULTS There was a significant reduction in tumour growth in mice that received EP with bleomycin. Apoptotic cells in tumours at 24 h after treatment with EP plus bleomycin showed a significant difference compared with the other three groups, but not at 12 h after treatment. CONCLUSIONS These results indicate the possibility that EP with bleomycin could be effective as an ablation therapy for prostate cancer, especially androgen-independent cancer. [ABSTRACT FROM AUTHOR]