Nanoparticle delivery of diphtheria toxin-encoding DNA selectively expressed in ovarian cancer cells reduced the burden of ovarian tumors in mice, and researchers expect this therapy could be tested in humans within 18 to 24 months, according to a report in Cancer Research, a journal of the American Association for Cancer Research.
Although early stage ovarian cancer can be treated with a combination of surgery followed by chemotherapy, there are currently no effective treatments for advanced ovarian cancer that has recurred after surgery and primary chemotherapy. Therefore, the majority of treated early stage cancers will relapse.
"This report is definitely a reason to hope. We now have a potential new therapy for the treatment of advanced ovarian cancer that has promise for targeting tumor cells and leaving healthy cells healthy," said lead researcher Janet Sawicki, Ph.D., a professor at the Lankenau Institute for Medical Research.
Sawicki and colleagues at the Massachusetts Institute of Technology evaluated the therapeutic efficacy of a cationic biodegradable beta-amino ester polymer as a vector for the nanoparticle delivery of a DNA encoding diphtheria toxin suicide gene. These nanoparticles were injected into mice with primary or metastatic ovarian tumors.
To test the efficacy of this technique, the researchers measured tumor volume before and after treatment. They found that while treated tumors increased 2-fold, this was significantly less than the between 4.1-fold and 6-fold increase in control mice.
Furthermore, four of the treated tumors failed to grow at all, while all control tumors increased in size. Administration of nanoparticles to three different ovarian cancer mouse models prolonged lifespan by nearly four weeks and suppressed tumor growth more effectively, and with minimal non-specific cytotoxicity, than in mice treated with clinically relevant doses of cisplatin and paclitaxel.