AUGUSTA, Ga. A protein that helps regulate expression of androgen receptors could prove a new focal point for staging and treating testosterone-fueled prostate cancer, Medical College of Georgia researchers say.
Levels of the protein, βarrestin2, are lower in some prostate cancer cells than in normal prostate cells while expression of testosterone-fed androgen receptors is higher, they report in Proceedings of the National Academy of Sciences Online Early Edition this week.
"An increase in the number of androgen receptors is believed responsible for prostate cancer progression in men with advanced disease," says the study's corresponding author, Dr. Yehia Daaka, Distinguished Chair in Oncologic Pathology in the MCG School of Medicine.
With increased numbers of androgen receptors, prostate cancer can make use of the limited testosterone available after a diseased prostate gland is removed or after testosterone production is blocked by drug therapy. In fact, the increased number of androgen receptors may mutate so they can start feeding off other steroids or even growth factors, Dr. Daaka says.
These wily skills help explain why cancer returns despite initially promising treatment results.
"It is clear that signaling by the androgen receptor is paramount for not only the initiation but also the progression of the disease, including escape to a hormone-refractory disease," he says. Moves androgen receptors make to support cancer growth make it "unbeatable at this point," for some patients.
However increased levels of βarrestin2 appear to halt the potentially deadly increase in androgen receptor expression, the MCG research team has found.
Androgen receptors have co-factors that can activate or repress their activity. "You could make the leap and say perhaps prostate cancer initiation and progression may be regulated by expression or non-expression of these co-factors," says Dr. Da
|Contact: Toni Baker|
Medical College of Georgia