Sildenafil, the active ingredient in Viagra, may do more than treat erectile dysfunction. Researchers in Israel reported that the drug appears to help keep cancer from spreading by disrupting how cancer cells use cholesterol, a shift they say could open a new way to interfere with metastasis.
The finding matters now because it comes from both lab work and a large patient-record analysis. In experiments on mouse and human cancer cells, sildenafil slowed cholesterol transport and made the cells less able to metastasize. In medical records from five million patients within Clalit Health Services, people with cancer who were also taking sildenafil appeared to survive longer than similar patients who were not.
Ayelet Erez said the team uncovered a new biological pathway linking a well-known signaling molecule to cholesterol regulation inside cells, and that the pathway could be harnessed to interfere with cancer cells' ability to form metastases. The researchers found that cGMP can bind to a protein involved in cholesterol transport, and that higher cGMP levels reduce that transport. In another sign that the pathway may matter, combining sildenafil with statins further limited metastasis, and cancer patients who took both drugs were even less likely to die of cancer in the analysis.
That is promising, but it is not proof. The work was published in Cancer Research, and the researchers themselves said more studies will be needed to verify the findings and determine whether the effect is clinically meaningful. The record analysis shows an association, not a cure, and the lab results do not yet tell doctors whether sildenafil can be used as a cancer treatment in people.
For now, the study leaves a sharper question than the one that brought attention to sildenafil in the first place: whether this common drug, alone or with statins, can actually be turned into a practical way to slow metastatic cancer.
