New Protein Target Discovered for Prostate Cancer Treatment

Cell surface protein found to promote cancer growth.

Prostate cancer is projected to cause more than 27,000 deaths in 2015 as the second leading cause of cancer death in American men.

In an effort to slow down this epidemic, researchers have identified a promising therapeutic target in the treatment of the disease. In a study conducted at the University of Southern California, investigators found evidence that a newly discovered cell surface protein found in G-protein coupled receptors (GPCRs) promotes the growth of prostate cancer cells.

The GPR158 protein was discovered as the researchers were searching for new glaucoma drug targets.

"When a prostate cancer tumor is in its early stages, it depends on hormones called androgens to grow," corresponding author Nitin Patel, PhD, said in a press release. "Eventually it progresses to a more lethal form, called castration-resistant prostate cancer (CRPC), and is resistant to drugs that block androgen receptors. We found that GPR158, unlike other members of the GPCR family, is stimulated by androgens, which in turn stimulates androgen receptor expression, leading to tumor growth."

To evaluate the protein, the researchers utilized a conditional Pten knockout mouse model of prostate cancer.

The study found a link between GPR158 and neuroendocrine transdifferentiation (NED) of epithelial prostate tumor cells. This process is a vital component in the development of resistance to contemporary androgen receptor-target therapies.

The researchers also discovered a recurrence of prostate cancer in patients with elevated GPR158 expression, which indicates that GPR158 protein may serve as an ideal target for new prostate cancer treatments.

The researchers will next evaluate the molecular pathways that are involved in the functional role of GPR158 in NED for the development of CRPC in order to examine potential GPR158-targeted antibody treatments.