21 December 2021
Recent research from the Malaghan Institute, funded by the Prostate Cancer Foundation of NZ has uncovered a new way prostate cancer could be targeted by immunotherapies.
The study, which has recently been published in Frontiers in Immunology, found that immune cells, called MAIT cells, that can reside in prostate tissue, function abnormally and have an abundance of a molecule called PD-1 on their surface. When these MAIT cells were activated using a vitamin B variant and the PD-1 molecule was blocked, it resulted in anti-tumour activity that destroyed the cancer cells.
This research was conducted by Dr Ellie May Jarvis as part of her PhD with the Malaghan Institute.
“Immunotherapies that effectively treat prostate cancer are not yet a standard of care. This dual strategy of activating MAIT cells and blocking PD-1 could offer a potential way of treating malignancies including prostate cancer,” says Dr Robert Weinkove, Malaghan Institute Clinical Director, who supervised the research.
Prostate cancer is one of the most prevalent cancers that affect men. Though it can affect men of any age, the chances of developing prostate cancer increase dramatically with age. 1 in 8 Kiwi men will be diagnosed with the condition in their lifetime. About 4,000 will be diagnosed this year and over 700 will die.
Current treatments for prostate cancer can involve surgery, radiotherapy, chemotherapy or medications that slow the growth of the cancer. Some of these treatments can cause side-effects, so the search for ways to prompt our own immune system to target and destroy cancer cells is important. Immunotherapy is routine for some cancers but has not been highly effective for prostate cancer to date.
The Chief Executive of the Prostate Cancer Foundation of NZ, Peter Dickens, says the findings hold great promise. “Along with providing vital support and information to the 42,000 men and those around them living with prostate cancer in our country, we are committed to doing what we can do to support research to find new therapies that will make a positive difference. While there is a long way to go, we are enormously proud to have supported Dr Jarvis and the team in this research and we look forward to seeing further developments in the field of immunotherapy to treat prostate cancer.”
Dr Jarvis says her research involved experimental work using blood cells from healthy donors and people with prostate cancer in the lab. “I’d like to thank Professor John Nacey, Dr Brendan Luey and Prof Brett Delahunt who helped me to recruit patients for this study. More work needs to be done to understand if it can be applied in clinical trials, but it’s a promising starting point,” says Dr Jarvis.
“We and other researchers in New Zealand and overseas are exploring various immunotherapies that activate MAIT cells, and our research suggests that blocking PD-1 in conjunction with these might be important for cancer therapy.”