To grow, spread and be deadly, prostate cancer feeds off male hormones like testosterone. When the cancer spreads outside the prostate, men are typically treated with hormone therapy, which cuts off the supply of testosterone and slows tumour growth.
But in some cases, the cancer continues to grow even without testosterone around. It evolves into castrate resistant prostate cancer (CRPC) and becomes incurable. The big question: how is it possible for prostate cancer to grow when its testosterone supply has been cut off? A Canadian team is researching a new discovery – that the cancer is actually using cholesterol to feed its growth by changing it into testosterone.
“Cholesterol is really important for all cells. The more quickly the cell grows, the more cholesterol it needs,” says Dr. Michael Cox, senior scientist at Vancouver Prostate Centre. “In prostate cancer, testosterone is the key driver, and cholesterol is the required building block for testosterone.”
Stopping the cholesterol transformation
Dr. Cox, along with Dr. Kishor Wasan, Professor and Former Dean in the College of Pharmacy and Nutrition at University of Saskatchewan, discovered that CRPC cells contain much more of a certain molecule than they should. They found that this molecule captures cholesterol from the body and delivers it to cancer cells, where it is transformed into testosterone to fuel cancer growth.
Drs. Cox and Wasan are looking at common cholesterol-lowering drugs, called statins, to block this molecule, cutting off cholesterol’s pathways into the prostate cancer cells. No cholesterol means no testosterone, which means cancer cells starve and stop growing.
Living with CRPC
Dr. Wasan says:
“It’s not always as simple as removing the prostate or blocking hormones – you can’t always eliminate the cancer that way.”
Eric Huffey taking part in Movember
to raise funds and awareness
for prostate cancer
Eric Huffey is living with an advanced form of prostate cancer and is being treated with hormone therapy. He knows it could eventually stop responding and become CRPC and is happy that Movember and Prostate Cancer Canada are supporting this research.
“In one sense, it’s almost too hard to believe, because if every prostate cancer cell is going to stop growing of a lack of cholesterol, then maybe it could be considered a cure,” says Eric. “I’m on cholesterol pills myself, so who knows whether that’s helping me in my prostate cancer fight.”
Eric was diagnosed at 55. Eight years after surgery, his PSA started to rise. He was given the option of radiation, but did not want to risk the side effects. Another seven years later, his PSA reached unacceptable levels according to his doctor, and he started intermittent hormone therapy. He recently finished his third round in four years.
“We’ll see how long or short it is before I go back on hormone therapy, and of course at some point it will become permanent,” he says.
Dr. Kishor Wasan
“Research like Dr. Cox’s is good. Any time life can be extended, it’s positive news. That’s the number one thing every prostate cancer patient is hoping for.”
What’s next?
The team is working to create a new therapy that, in combination with statins, will reduce the amount of cholesterol in the body and stop cholesterol entering prostate cancer cells.
“The hope is that we’ll be able to turn advanced prostate cancer into a manageable condition, not a lethal disease.”
This project is proudly funded by Movember and awarded by Prostate Cancer Canada as part of the Discovery Grant program. In 2019, this was one of ten projects awarded through the program to save and improve more lives of those affected by prostate cancer.