(NEW HAVEN) -- Combining Salmonella injections with radiation therapy in mice has shown promising new results for improved cancer treatment. The findings by a team of Yale Cancer Center scientists in collaboration with Vion Pharmaceuticals, New Haven, Conn., were reported at the 91st Annual Meeting of the American Association for Cancer Research in San Francisco today.
The researchers had previously developed a tumor-targeting, genetically-altered strain of Salmonella -- the same bacterium that, in its unaltered or wild type form, can cause food poisoning and septic shock. It was shown to be safe in animal studies, significantly prolonging the lives of mice by suppressing tumor growth. The genetically altered bacteria are currently being tested in Phase I clinical trials with human cancer patients.
"For a number of reasons, we thought that combining these Salmonella with X-ray treatments might be a good strategy for improved therapy," noted John Pawelek, M.D., senior research scientist at the Yale University School of Medicine. "It was exciting to see the positive results."
In a typical experiment, tumor suppression by a combination of X-rays and Salmonella was greater than that seen with either X-rays or Salmonella alone. In fact, the effects of the combination were greater than what would have been expected by the simple addition of the effects of either treatment alone. These results were seen against two different types of melanoma, as well as in colon and breast cancers.
"It appears that the combination of genetically engineered Salmonella with radiotherapy could be a new and beneficial treatment for solid tumors," said Pawelek. "Because of the large number of cancer patients who receive radiation therapy, the potential impact of this finding is tremendous."
Collaborating with Pawelek at Yale were Sara Rockwell, Ph.D. and K. Brooks Low, Ph.D. along with David Bermudes, Ph.D. of Vion Pharmaceuticals.