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OVC Researchers’ New Approach Holds Promise in Fighting Ovarian Cancer

Image of an ovarian tumour that has normalized blood vessels.A novel approach to ovarian cancer research at the University of Guelph’s Ontario Veterinary College (OVC) is delivering promising results.

“The treatment for women with advanced ovarian cancer has not changed appreciably in 40 years,” notes OVC Biomedical Sciences professor Jim Petrik. Current treatments have limited effectiveness, focusing on destroying the tumour’s blood supply and trying to starve it.

“A cancerous tumour grows rapidly with a vast expanding blood vessel system, but it is a poorly functioning blood system,” explains Petrik.

A recent groundbreaking study from his lab showed opening up these blood vessels — vascular normalization —is potentially more effective in fighting ovarian cancer than destroying the tumour’s blood supply.

The study was the first to investigate this approach in mouse models with advanced ovarian cancer.

Dr. Jim Petrik, Department of Biomedical Sciences, Ontario Veterinary College, University of GuelphHis research team developed an approach to prune the dysfunctional blood vessels, establishing a tumour with a good blood supply. This pathway was then used to deliver treatment to the tumour, including new approaches such as oncolytic viruses and immunotherapy.

The latter work, in collaboration with Profs. Byram Bridle and Sarah Wootton, in OVC’s Department of Pathobiology, explores the power of oncolytic viruses to infect and kill cancer cells and to stimulate anti-tumour responses in the body. Part of the response is to also recruit and activate nearby immune cells which then also enter the tumour.

The study not only showed an uptake of the oncolytic virus, but also a dramatic increase in uptake and activation of the immune cells the virus produces.

“Once we’ve activated and recruited those immune cells, they initiate a very potent anti-tumour effect,” says Petrik. “We see this in the primary tumour, but importantly, we see the exact same mechanism replicated in the metastatic tumours. This is critical because in ovarian cancer, as with a lot of other late stage cancers, it’s the metastatic disease that ultimately causes a lot of morbidity.”

Close collaborations with McMaster University and Western University is further advancing the work.

“We’re collaborating with clinicians at both medical schools as we try and transition this to a Phase 1 Clinical Trial with human patients,” says Petrik. “We’re working with human ovarian cancer cells and so far we’ve been able to show that the therapy is equally as effective in human cancer samples as we see with our animal model.”

An important translational step will include bringing the therapy to companion animals with naturally occurring cancers. He recently received funding from OVC Pet Trust to begin this work.

OVC’s Mona Campbell Centre for Animal Cancer is the ideal place to investigate these therapies in dogs and cats with spontaneous disease and offer these treatments.

“Companion animals live in the same environment that we do and their naturally occurring disease is similar to what we see in humans,” says Petrik. “If we have therapeutic success in the mouse models and then also with companion animals, we may have a therapy that’s far more robust and will have much better efficacy in human cancer patients.”

“We’re taking a novel approach to a very challenging problem,” notes Petrik. “There’s a lot of hope that this is going to really improve our ability to treat these very difficult diseases.”

(Photo: Image of an ovarian tumour that has normalized blood vessels. The blue are tumour cells, the red are endothelial cells that line the inside of blood vessels and the green are the smooth muscle cells that are present in mature, normalized blood vessels.)