Dalhousie Medical School cancer researcher Dr. Patrick Lee has proven that a common virus can infect and kill breast cancer stem cells.
“We suspected that reovirus might be effective against cancer stem cells, because we have shown time and again how well it destroys regular cancer cells,” said Dr. Lee (pictured middle), Cameron Chair in Basic Science Research at Dalhousie Medical School and the first in the world to discover that a benign and naturally occurring virus could selectively infect and kill cancer cells without harming healthy cells.
It is only within the past few years that the scientific community has understood the full significance of cancer stem cells and the urgent need to find a means of eliminating them.
“Cancer stem cells are essentially mother cells,” explains Dr. Lee. “They continuously produce new cancer cells, aggressively forming tumors even when there are only a few of them.”
Cancer stem cells are difficult to kill as they respond poorly to chemotherapy and radiation. As Dr. Lee notes, “You can kill all the regular cancer cells in a tumor, but as long as there are cancer stem cells present, disease will recur.”
Unlike most cancer studies, which use cancer cell lines developed for laboratory use, this study used fresh breast cancer tissue. This cancer tissue was removed from a patient of Dr. Carman Giacomantonio (pictured left), an assistant professor of surgery and surgical oncologist at Capital Health. Also the clinical leader of Cancer Care Nova Scotia's surgical oncology network, Dr. Giacomantonio is working with Dr. Lee on the reovirus research, along with research assistant Cheryl Dean and post-doctoral fellow Dr. Paola Marcato (pictured right), who is funded by the Alberta Heritage Foundation.
“This finding promises to be the basis for a major new approach to dealing with many different types of cancer,” says Dr. Gerry Johnston, Dalhousie Medical School’s associate dean of research. “Clearly, the more we understand about the molecular basis for cancer the better equipped we are to deal with cancer in a very directed fashion – a way that spares healthy tissue and eradicates only the disease.”
“We are incredibly proud to have provided funding for Dr. Lee’s research,” said Nancy Margeson, CEO, Canadian Breast Cancer Foundation – Atlantic Region. “For an organization dedicated to a future without breast cancer, research is the most significant part of our work. To have a breakthrough of this magnitude, substantiates our faith that one day our vision will come true. The thousands of people who have put their belief in the work of CBCF should take pride in this achievement.”
In addition to its ability to kill cancer cells and cancer stem cells, reovirus stimulates the anti-cancer immune system. Since virus therapy also invokes an anti-virus response, Dr. Lee and post-doctoral fellow Dr. Shashi Gujar are working on a way to harness the immune system so it attacks cancer cells while allowing the virus to freely infect and destroy cancerous cells.
“Refining this two-pronged approach to killing cancer is our next step,” says Dr. Lee. “We are taking advantage of the natural characteristics of reovirus and the immune system itself to create a powerful virus-based anti-cancer therapy.”
Illustration: Dalhousie University.
Dalhousie University News Release (04/13/09)
Medical News Today (04/08/09)
Science Daily (04/09/09)
Abstract (Molecular Therapy; (03/17/09))