Research has uncovered a number of promising drug targets to halt the progression of prostate cancer, including proteins that inhibit the immune response to molecules that drive growth of a tumor's blood vessels. By taking aim at one protein in particular, scientists have been able slow the growth of prostate cancer in mice and also activate a kill switch in the tumor's cells.

The protein, called P21 activated kinases-1 (PAK-1), plays a key role in the development of prostate cancer cells. Researchers at the University of Georgia (UGA) liken it to an on-off switch for cancer, and had previously tried to intervene with a molecule called IPA-3 that is known to inhibit its activity. They encountered problems, however, with the body's metabolism breaking the molecule down before it could properly perform its role.

But Brian Cummings, associate professor at UGA's College of Pharmacy, has now developed a protective vessel that shields IPA-3 from destruction, allowing it time to go to work on the PAK-1 protein. This assistance came in the form of a tiny nanoscale bubble that houses the molecule as it is being delivered.

Called a liposome, the researchers found that injecting IPA-3 intravenously inside this shell significantly slowed the progression of prostate cancer in mice. Furthermore, it was also shown to trigger self-destruction of the cancer cells, a process known as apoptosis.

"When we first began these experiments, we injected IPA-3 directly into the bloodstream, but it was absorbed so quickly that we had to administer the treatment seven days a week for it to be effective," says study co-author Somanath Shenoy, an associate professor in UGA's College of Pharmacy. "But the liposome that Dr. Cummings created makes the IPA-3 much more stable, and it reduced the treatment regimen to only twice a week."

The team says that the early results indicate the technique may one day develop into a suitable treatment for humans, but there is more work to do first, namely determining what the adverse effects might be.

"The results of our experiments are promising, and we hope to move toward clinical trials soon," says Shenoy. "But we must figure out what side effects this treatment may have before we can think about using it in humans."

The research was published in the journal Nanomedicine.