Additional Gene Therapy with rAAV-wt-p53 Enhanced the Efficacy of Cisplatin in Human Bladder Cancer Cells

Abstract

Objective:Gene therapy is defined as the treatment of an acquired or inherited disease by transfer of genetic material. The most common strategies in gene therapy of bladder cancer are corrective, inductive and cytotoxic gene therapy. Mutations in the p53 tumor suppressor gene are the most common molecular genetic abnormalities in bladder cancer and p53 gene transfer in the human bladder cancer cell line by adenoviral or other vectors was demonstrated to be cytotoxic. However, so far there has been no report of adeno-associated virus-2 vector-mediated p53 gene deliveries in bladder cancer. In this study, wild-type p53 cDNA was transfected into the bladder cancer cells, using the adeno-associated virus-2 vector, and the capability of rAAV-wt-p53 gene therapy in bladder cancer was evaluated in vitro. Method:Bladder cancer cell lines 5637 were transduced with adeno-associated virus-2 vectors containing wild-type human p53 gene (rAAV-wt-p53). Gene expression and transcriptional activation of p53 was determined by Western blot analysis. The cellular growth inhibition and apoptosis of rAAV-mediated p53 transfection were assessed by flow cytometry. The combination effect of rAAV-wt-p53 and cisplatin was measured by MTT assay. Results:The virus rAAV efficiently enters the cells and expresses its gene products. The gene product of rAAV-wt-p53 is cytotoxic to bladder cancer cells. The bladder cell line 5637 was found to experience a synergistic killing effect when rAAV-wt-p53 was used in combination with cisplatin. Conclusion: rAAV-mediated p53 gene transfer could offer a powerful novel therapeutic approach in bladder cancer.