A Western research team is developing a way to diagnose prostate cancer without resorting to surgery, possibly reducing the number of biopsies that need to be conducted.
A team led by Len Luyt, a Chemistry professor cross-appointed to Medical Imaging, has developed a new class of imaging agents targeting the prostate. Molecular imaging using trace amounts of radioactive metals or dye administered by injection or patch would provide a detailed picture of the prostate, allowing for more accurate detection of tumours.
“Prostate cancer is one area where there is a need to more confidently diagnose a tumour and estimate the extent of the disease, to avoid over-treatment,” said Luyt, a Senior Scientist with the London Regional Cancer Program. “Our goal is to create imaging agents that will improve treatment decisions by accurately detecting and localizing cancer, so we know if treatment is needed and where to direct it. This can have a real effect on the lives of prostate cancer patients.”
One in eight Canadian men will be diagnosed with prostate cancer in their lifetime. It is the most commonly diagnosed cancer among Canadian men with 21,600 new cases in 2016 and 4,000 deaths.
By adding radioactive metals into peptides that target tumours, cameras can then locate a tumour without a biopsy. Peptide receptors are located on the surface of tumour cells.
Having his research group embedded within a cancer research lab helps bring to light what he calls “unmet clinical needs,” such as the need for a diagnosis without a biopsy. That close connection also came into play with a project related to breast and other cancers likely to metastasize, which previously had no known molecules that would target them.
Last year, Luyt’s colleague at the London Regional Cancer Program and Oncology, Biochemistry and Surgery professor, Eva Turley, discovered a new peptide receptors called RHAMM (receptor for hyaluronan-mediated motility). This protein in humans regulates cell movement and stem cell differentiation and is overexpressed in breast cancer.
Turley and Luyt received the 2016 WORLDiscoveries Vanguard Award for Innovator(s) of the Year for their work with the RHAMM in finding treatments for a variety of inflammatory conditions including bronchopulmonary dysplasia in premature infants, arthritis and emphysema.
Luyt’s team screens millions of different compounds to see which will interact with the cancer target, developing large ‘libraries’ of peptides. Peptides play an important role in the body as hormones and neurotransmitters by relaying signals from one nerve cell to another.
Researchers don’t go directly to the library ‘shelf’ for a specific peptide, Luyt said.
“The starting point is typically a completely random situation,” he explained. “As we discover compounds that target cancer, we create a focused library set up with portions of molecules we know are important, and start to make other changes to make the molecule even better.”
Luyt and Turley started a research project to find the peptides that would target RHAMM, discovering new molecules that bond well. The molecules show great potential as a drug and the team is working with a pharmaceutical company to move to clinical trials.
“This is an example of how chemists are able to collaborate with cancer scientists to move an academic biology discovery forward,” Luyt said.
“Chemists are not historically part of health research in Canada, but they play a key role in translating scientific discovery to clinical use. Specific applied projects may be more visible, but we need the fundamental science discoveries chemists can make to drive innovation, create new diagnostics and therapeutics for cancer and result in better outcomes.”