Researchers at the Mayo Clinic campus in Florida have found that a drug now being tested to treat a range of human cancers significantly inhibited colon cancer development in mice. Because the agent appears to have minimal side effects, it may represent an effective chemopreventive treatment in people at high risk for colon cancer, the investigators say.

Their study, published in the Feb. 15 issue of Cancer Research, found that use of the agent, enzastaurin, significantly reduced development of cancerous colon tumors in treated animals. Furthermore, the tumors that did develop in the mice were of a lower grade, which meant they were less advanced and aggressive than the tumors seen in animals not given the drug. "There is need for an agent that has a proven ability to reduce colon cancer risk, and this study suggests that enzastaurin could be uniquely effective," says the study's senior investigator, Nicole Murray, Ph.D., of the Department of Cancer Biology.

Individuals at high risk for colon cancer often develop numerous precancerous colon polyps, which must be periodically removed during a colonoscopy, Dr. Murray says.

The laboratories of Dr. Murray, and her collaborator and co-author, Alan Fields, Ph.D., chair of the Department of Cancer Biology, focus on characterizing the genes involved in different stages of colon carcinogenesis. They have zeroed in on the protein kinase C (PKC) family of enzymes as major players in cancer development and progression, but it has taken them years to understand the different roles of each type of PKC molecule or "isozyme…