U of G Prof Helps Explain Cancer’s Spread

December 21, 2012 - News Release

Canadian scientists – including a University of Guelph professor – have made a major discovery about how cancer spreads.

They found that proteins produced in normal cells near a tumour affect the cancer’s ability to spread to other tissues of the body, a process called metastasis. The research was published Thursday in the journal Cell.

Guelph’s Prof. Alicia Viloria-Petit, a biomedical scientist and investigator in the Ontario Veterinary College’s new Institute for Comparative Cancer Investigation, worked with researchers Valbona Luga and Liang Zhang on the study. Luga and Zhang work with Jeff Wrana, an international leader in cancer research at Mount Sinai’s Samuel Lunenfeld Research Institute in Toronto.

“Their findings are a breakthrough in the field of breast cancer metastasis,” Viloria-Petit said.

Doctors might now be able to target one of the proteins, called Cd81, to halt the spread of breast cancer and other tumours. The newly identified protein is part of tiny fragments of cells called exosomes.

Tumour cells release exosomes to affect neighbouring cells. The researchers discovered that normal cells surrounding the tumour also secrete exosomes, which help the tumour cells to spread.

“The existence of vesicles or cell particles – exosomes -- released to the extracellular environment by cancerous cells has been known for a while,” Viloria-Petit said. “But it’s the first time normal cells present in the tumour surroundings have been identified as a significant source of these vesicles, which are able to actively communicate with the cancer cells to promote their migration and colonization of distant organs -- metastasis.”

Researchers might target these molecules to block metastatis, she added.

Viloria-Petit worked with Luga and Zhang on the animal studies and helped design experiments that showed how exosome-mediated signalling affects breast cancer metastasis. The research, which was funded by the Terry Fox Research Institute and the Canadian Institutes of Health Research, also involved Dr. Mark Basik from the Lady Davis Institute for Medical Research at Jewish General Hospital in Montreal.

“This study is a very good example of the type of work that can be achieved through a multidisciplinary, multi-institutional collaboration,” she said. “I am extremely grateful to the Wrana laboratory for inviting me to be part of the team. This was a logical extension to the work I did there as a post-doctoral fellow and helped me gain more experience in the breast cancer metastasis field, a line of research I continue to pursue now as an independent investigator here at Guelph.”

A U of G professor since 2009, Viloria-Petit studies how cells change to enable cancer metastasis. By understanding how the process occurs, she hopes to help develop more effective treatments for advanced breast cancer.

She received the prestigious Jennifer Dorrington Award from the Banting Research Foundation – Canada’s oldest medical research institute -- and was one of five Canadian recipients of a Banting Research Foundation award in 2009.

For media questions, contact Communications and Public Affairs: Lori Bona Hunt, 519-824-4120, Ext. 53338.

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