Effect of p53 gene transfer and cisplatin in a peritonitis carcinomatosa model with p53-deficient ovarian cancer cells.

OBJECTIVE

To determine whether combination treatment consisting of p53 gene transfer and cisplatin (CDDP) improves prognosis of ovarian cancer patients with peritonitis carcinomatosa, we tried this therapy in a peritonitis carcinomatosa model that we developed.

METHODS

A human ovarian adenocarcinoma cell line, HRA, which has homozygous deletion of the p53 gene, was used. For p53 gene transfection, we used a recombinant adenovirus carrying a wild-type p53 gene (AxCAp53). To determine the efficiency of the recombinant adenovirus to transduce HRA cells, the cells were infected with AxCALacZ, and the transduced cells were detected by beta-galactosidase staining. The expression of the p53 protein was monitored by Western blot analysis up to 15 days after infection of 50 MOI AxCAp53. The combination effect of AxCAp53 and CDDP was evaluated by 3-(4, 5-dimethelthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. Apoptotic cells were assessed morphologically by staining with Hoechst 33258. For the peritonitis carcinomatosa model in this study, we used severe combined immunodeficiency mice with an intraperitoneal injection of HRA cells.

RESULTS

The p53 protein was expressed at 24 h after infection with AxCAp53 and disappeared on the 14th day. The present in vitro study showed that wild-type p53 gene transduction significantly enhanced sensitivity to CDDP and the apoptotic index in HRA cells. A significant survival advantage was observed in the combination treatment of AxCAp53 and CDDP compared with single treatments. However, the repetitious treatment did not show significant survival advantage in the long term.

CONCLUSION

The present study suggests that intraperitoneal treatment with AxCAp53 and CDDP is potentially useful as an adjuvant therapeutic modality for peritonitis carcinomatosa, although further study is needed to improve the long-term survival for those patients.