Antidepressants show promise for treating prostate cancer

"Suppressing this enzyme and combining it with current therapies may provide a better way to manage and cure men with metastatic prostate cancer," says Leland Chung. (Credit: hit thatswitch/Flickr)

There’s new evidence that certain drugs used to treat depression might also help stop the growth of prostate cancer.

The antidepressants in question are MAO-A inhibitors. They suppress monoamine oxidase A, an enzyme that has been linked to depression, as well as to autistic behaviors, aggression, and anxiety.


A recent study with mice shows that suppressing the enzyme reduces prostate tumor growth.

“This is the first paper showing that MAO-A plays an important role in prostate cancer progression and metastasis. MAO-A inhibitors may provide an unmet need in cancer treatment,” says Jean C. Shih, a professor at the University of Southern California School of Pharmacy and co-corresponding author of the research published in the Journal of Clinical Investigation.

“When this enzyme is not suppressed, it produces a tumor-rich environment that fuels the growth and metastasis of prostate cancer cells,” says Leland Chung, corresponding author of the paper and director of the Uro-Oncology Research Program at the Cedars-Sinai Samuel Oschin Comprehensive Cancer Institute. “Suppressing this enzyme and combining it with current therapies may provide a better way to manage and cure men with metastatic prostate cancer.”

Stop cancer from spreading

Recently, scientists noticed that MAO-A levels were especially high in individuals suffering from prostate cancer—but were unable to determine why.

Shih, Chung, and their team found that MAO-A produces an oxygen-rich, free-radical environment for cancer cells to thrive in—promoting stronger growth and invasiveness. They were able to control this effect in mice, strongly suggesting that the drugs already in existence to inhibit MAO-A for mental depression can do double-duty to suppress prostate cancer.

“We’re happy to be able to translate our discoveries in basic research to clinical application,” says Shih, who has studied MAO-A for 30 years and is also the director of the USC-Taiwan Center for Translational Research.

Next steps include a Phase II clinical trial of the MAO-A inhibitor in prostate cancer, in collaboration with Mitchell Gross of the Keck School of Medicine of USC and colleagues in USC Norris Cancer Center.

The National Institutes of Health, the Department of Defense, the USC-Taiwan Center for Translational Research, and the Daniel Tsai Family Fund supported the research.

Source: University of Southern California