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A safer way to combat cancer

Virus that destroys tumour cells has been given a helping hand

Ovarian cancer, the leading cause of death of all female reproductive cancers, might have met its match with a new tumour cell-destroying duo.

A new protein, being analyzed in the lab of Dr. Jim Petrik at the University of Guelph in collaboration with researchers at Harvard University, has the ability to shrink the size of ovarian tumours in mice by up to 50 per cent, and increase tumour uptake of chemotherapy drugs.

Researchers are now combining this protein, called 3TSR, with the virus from Newcastle disease to promote blood flow into tumours and safely destroy tumour cells.

Newcastle disease is an oncolytic virus, which means that it terminates tumour cells without damaging healthy body cells. Kathy Matuszewska, a PhD candidate from the Department of Biomedical Sciences, and a team of researchers are using 3TSR to help enhance this process.

Tumours’ rapid growth cause blood vessels within them to be poorly organized, leading to obstructed blood flow into the tumour. The effectiveness of Newcastle disease virus relies on the vessels that deliver the virus into the tumour. 3TSR has the ability to promote stable blood flow by destroying abnormal vessels, while leaving healthy ones intact. As a result, researchers predict that Newcastle disease virus will reach the tumour more efficiently with the aid of 3TSR.

They also found that the combination of 3TSR and oncolytic viruses, such as Newcastle disease, stopped the spread of secondary tumours (which develop from the original tumour in a new area and can complicate treatment).  

Newcastle disease is central to this research because it is found only in avian species. Most humans haven’t encountered it, so they haven’t developed the immunity to extinguish it. Healthy cells in the body have the ability to combat Newcastle disease through the development of an immune response. However, tumours are unable to protect themselves, due to the diminished immune activity that is inherent within them. This allows the virus to survive long enough to reach the tumour, without causing side effects and attacking the host.

“We also want to investigate 3TSR further in combination with other treatments, in hopes that it will increase their efficacy. Combination therapy has the potential to really help women with advanced stage cancer in the future, considering the limited treatment options available to them today,” says Matuszewska.

This research is in collaboration with advisors Drs. Byram Bridle and Sarah Wootton. Funding is provided by the Canadian Institutes of Health Research and the OVC Doctoral Scholarship.

Article by OVC SPARK writer Sydney Pearce

(Top photo: Kathy Matuszewska, PhD candidate, Department of Biomedical Sciences, with Lisa Santry, PhD candidate, Department of Pathobiology.)