'Erectile dysfunction' drugs can help detect cancer cells
08 December, 2006
Drugs that help men with erectile dysfunction now also show promise in unmasking cancer cells so that the immune system can recognize and attack them, say scientists at the Johns Hopkins Kimmel Cancer Center.
Tests at Hopkins on mice with implanted colon and
breast tumors showed that tumor size decreased two- and threefold
in sildenafil-treated
animals, compared to mice that did not get the drug. In mice engineered
to lack an immune system, tumors were unaffected, proof of principle,
the scientists say, that the drug is abetting the immune system's
own cellular response to cancer.
In a report published in the Nov. 27 issue of the Journal of Experimental Medicine, researchers revealed that boosted levels of the chemical messenger nitric oxide appear to dampen the effects of a specialized cell that diverts the immune system away from tumors, allowing swarms of cancer-attacking T-cells to migrate to tumor sites in the rodents.
Lab-grown cancer cells treated with sildenafil showed similar results, as did tissue samples taken from 14 head and neck cancer and multiple myeloma patients.
Sildenafil, marketed under the trade name Viagra, is one of a class of drugs used to treat erectile dysfunction in millions of men, and in recent years, its ability to stimulate the production of NO has been investigated by experts in diseases linked to the activity of blood vessels and blood components.
