Slowing Ovarian Tumor Growth With Dipththeria Toxin DNA

Slowing Ovarian TumorA new technique for reducing the burden of ovarian tumors in mice might be available for testing in humans within 18 to 24 months.

Although early-stage ovarian cancer sometimes responds to surgery followed by chemotherapy, there are no effective treatments for advanced ovarian cancer that has recurred after surgery and primary chemotherapy. Therefore, most treated early-stage cancers recur.

Colleagues at the Massachusetts Institute of Technology evaluated the efficacy of a 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 drugs ovarian tumors.

Measuring tumor volume before and after treatment, the researchers found that although treated tumors increased in size by two-fold, the control mice experienced a 4.1-fold to six-fold increase.

Four of the treated tumors did not grow at all, but all control tumors in creased in size. Giving nanoparticles to three different ovarian drugs cancer mouse models prolonged life spans by almost four weeks and suppressed tumor growth more effectively, and with minimal nonspecific cytotoxicity, compared with mice receiving clinically relevant doses of cisplatin (Platinol) and paclitaxel (Taxol, Bristol-Myers Squibb).

Of prime importance is the need for the therapy to be able to reach the target. A major accomplishment of this research is the delivery of diphtheria toxin genes to the actual tumor site (the peritoneum).

Source: Cancer Res, August 1, 2009