Nanoparticle-Delivered Suicide Gene Therapy Effectively Reduces Ovarian Tumor Burden in Mice

There is currently no effective therapy for patients with advanced ovarian cancer. To address the need for a more effective treatment for this deadly disease, we conducted preclinical tests in ovarian tumor-bearing mice to evaluate the therapeutic efficacy of using a cationic biodegradable poly(beta-amino ester) polymer as a vector for nanoparticulate delivery of DNA encoding a diphtheria toxin suicide protein (DT-A). The promoter sequences of two genes that are highly active in ovarian tumor cells, MSLN and HE4, were used to target DT-A expression to tumor cells. Administration of DT-A nanoparticles directly to s.c. xenograft tumors and to the peritoneal cavity of mice bearing primary and metastatic ovarian tumors resulted in a significant reduction in tumor mass and a prolonged life span compared to control mice. Minimal nonspecific tissue and blood chemistry toxicity was observed following extended treatment with nanoparticles. DT-A nanoparticle therapy suppressed tumor growth more effectively than treatment with clinically relevant doses of cisplatin and paclitaxel. Our findings suggest that i.p. administration of polymeric nanoparticles to deliver DT-A encoding DNA, combined with transcriptional regulation to target gene expression to ovarian tumor cells, holds promise as an effective therapy for advanced-stage ovarian cancer. [Cancer Res 2009;69(15):6184-91]