A drug that has been used for years to kill tapeworms blocks a gene that promotes the spread of colon cancer, at least in cancer cells and mice.
Colon cancer is most serious when it spreads outside the colon to other organs, like the liver or lungs. It is this spread or metastasis that causes death.
Now German scientists have found a gene that begins the process of colon cancer metastasis. What’s more they’ve discovered that niclosamide, a medicine for tapeworms, blocks expression of that gene.
When beta-catenin is mutated, as it often is in colon cancer, it can trigger expression of S100A4/metastasin, the gene that drives metastasis. Niclosamide blocks S100A4/metastasin.
After discovering the important role of S100A4/metastasin in colon cancer metastasis, the research team screened 1,280 active medicines to see if one might inhibit S100A4. Niclosamide not only blocked protein expression, but when applied to cancer cells reduced their ability to divide, move, and form new cell colonies.
The scientists then grew colon cancers in mice and treated half of them with niclosamide. All of the control mice, who didn’t get the drug, developed liver metastases. But only one third (34.9%) of the treated mice did.
After treatment ended, the mice who were given niclosamide lived almost twice as long as the control animals (median 46.5 days versus 24 days).
The team will be moving to clinical trials to test safety and effectiveness in human patients, but those trials are not yet underway.
Ulrike Stein, PhD, and his team at the Max Delbruck Center for Molecular Medicine in Berlin concluded,
Niclosamide inhibits S100A4-induced metastasis formation in a mouse model of colon cancer and has therapeutic potential.
SOURCE: Stein et al., Journal of the National Cancer Institute, Online June 17, 2011.
What This Means for Patients
Although niclosamide is on the market and approved by the FDA to treat tapeworm infections, there is no evidence that it works in humans to keep colon cancer from spreading.
It may not even be safe for people with colon cancer, particularly if they are being treated with other medicine.
Hard as it is to wait, it is important that clinical trials show that it is both safe and effective as treatment for colon cancer before it is used for that purpose.