Their report appears as an electronic advance article of PNAS, the Proceedings of the National Academy of Sciences ( http://www.pnas.org/cgi/reprint/102/5/1649). The research was performed on human cells in the laboratory and was found effective against human cancer cells. Researchers say it will be at least a year before the discovery can be applied in a human clinical trial.
The Findings
For the first time, the Mayo Clinic research group provides laboratory evidence to describe a new mechanism by which cells lose the protection of tumor suppressors -- and therefore become vulnerable to cancerous cell growth. In particular, they show that Skp2 is the cellular player that interacts with FOXO1 by tagging it for destruction. This degradation of FOXO1 by high levels of Skp2, in turn, abolishes the ability of FOXO1 to suppress tumors. The result of their experiment indicates that human prostate cancer grows without the protection of the tumor suppressor protein FOXO1. Importantly, they also show that this loss of function can be reversed -- even in the presence of high levels of Skp2, by using chemicals that inhibit protein destruction, and thus block Skp2's action against FOXO1.
Significance of the Finding
"The major finding of our studies is that the tumor suppression function of FOXO1 is abolished due to Skp2-mediated protein degradation," says Haojie Huang, Ph.D., the urology researcher who performed the study. Co-investigator Donald J. Tindall, Ph.D., adds, "We've discovered a viable therapeutic t
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Contact: Robert Nellis
newsbureau@mayo.edu
507-284-5005
Mayo Clinic
14-Feb-2005