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Dalhousie researchers hit paydirt with discovery
HALIFAX, Nova Scotia—A group of Canadian researchers has pinpointed a common virus that could provide a new and effective approach to eliminating breast cancer stem cells—a key tool in the battle against the deadly disease.
The research team at Dalhouise Medical School in Halifax, Nova Scotia is led by Dr. Patrick Lee, who says he and his colleagues tested reovirus against breast cancer tissue extracted from patients and found that the virus attacked the cancer stem cells and surrounding cancer cells in the tissue samples. In addition, says the researcher, the reovirus stimulated the body's immune system to help ward off the cancer.
The team's breakthrough finding has been published in Molecular Therapy, a journal of the American Society of Gene Therapy.
Lee and his team are investigating how the twin strategies would work in patients. Researchers have been focused particularly on cancer stem cells, noting their role in metastasis and how they resist currently used therapies like chemotherapy. 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. They continuously produce new cancer cells, aggressively forming tumors even when there are only a few of them," Lee says.
Lee points out that cancer cells are difficult to kill as they respond poorly to chemotherapy and radiation.
"You can kill all the regular cancer cells in a tumor, but as long as there are cancer stem cells present, disease will recur," he says.
According to Dr. Brad Thompson, president and CEO of Oncolytics Biotech Inc., the preclinical work done by Lee and Oncolytics' other collaborators worldwide continues to support their efforts to develop Reolysin as a cancer therapeutic.
"Study after study has demonstrated that the reovirus can infect and kill up to two-thirds of all human cancer cells, while sparing normal cells," Thompson says. "Dr. Lee's study is yet another example demonstrating the potential of the reovirus."
According to Lee, Calgary-based Oncolytics is sponsoring all the reovirus human trials. The company made the first discovery of reovirus, a common virus that does not cause disease, killing cancer a decade ago.
Lee says he's optimistic that his team has found a key in destroying cancer stem cells, with research finding that human reovirus effectively targets and kills cancer stem cells in breast cancer tissue.
"The company owns all the intellectual properties on reovirus cancer therapy, but the Dalhousie Industry Liaison and Innovation office is working on my and my team's behalf in negotiation with the company on discoveries made here at Dalhouise," says Lee.
Unlike most cancer studies, which use cancer cell lines developed for laboratory use, this study used fresh breast cancer tissue removed from a patient of Dr. Carman Giacomantonio, a Capital Health surgical oncologist who is working with Lee on the reovirus research.
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, Lee and postdoctoral 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.
They are now trying to find a way to harness the immune system to destroy cancer cells while allowing reovirus to freely infect and kill cancer cells.
"Refining this two-pronged approach to killing cancer is our next step," says 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."
Lee's discovery is making waves throughout the world, gaining the attention of LeadDiscovery, a UK-based organization dedicated to promoting drug discovery and development. LeadDiscovery has identified the finding to be of particular interest to the drug development sector and will feature it in its next update to the global scientific community and pharmaceutical industry.
According to Thompson, the preclinical work done by Lee and Onoclytics' other collaborators worldwide continues to support their efforts to develop Reolysin as a cancer therapeutic.
"Study after study has demonstrated that the reovirus can infect and kill up to two thirds of all human cancer cells, while sparing normal cells," Thompson says. "Dr. Lee's study is yet another example demonstrating the potential of the reovirus."
Thompson also notes there is no licensing agreement in place "as Oncolytics holds extensive patent coverage in the area of using oncolytic viruses as cancer therapeutics."