Dalhousie Medical School cancer researcher Dr. Patrick Lee has proven that a common virus can infect and kill breast cancer stem cells.
This breakthrough finding is published in the current issue of Molecular Therapy, the prestigious journal of the American Society of Gene Therapy.
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, Cameron Chair in Basic Cancer Research at Dalhousie Medical School. "They continuously produce new cancer cells, aggressively forming tumours 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 tumour, but as long as there are cancer stem cells present, disease will recur."
Dr. Lee is optimistic that his team has found the key to destroying cancer stem cells. The researchers have recently shown that human reovirus, a common virus that does not cause disease, effectively targets and kills cancer stem cells in breast cancer tissue.
"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," remarks Dr. Lee, who was 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. A Calgary-based company, Oncolytics Biotech Inc., is testing reovirus in clinical trials to prove the treatments are safe and effective.
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, a Capital Health surgical oncologist who is working with Dr. Lee on the reovirus research, along with post-doctoral fellow Dr. Paola Marcato and research assistant Cheryl Dean.