Wednesday, December 16, 2009

Stem-cell activators switch function, repress mature cells

Source: Ohio State University Medical Center
Date: December 16, 2009

Summary:

In a developing animal, stem cells proliferate and differentiate to form the organs needed for life. A new study shows how a crucial step in this process happens and how a reversal of that step contributes to cancer. The study, led by researchers at the Ohio State University Comprehensive Cancer Center-Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, shows for the first time that three proteins, called E2f1, E2f2 and E2f3, play a key role in the transition stem cells make to their final, differentiated, state.

These proteins help stimulate stem cells to grow and proliferate. But once stem cells begin to differentiate into their final cell type - a cell in the retina or in the lining of the intestine, for example - the same three proteins switch function and stop them from dividing any more. The research also shows how these proteins can switch course yet again in cells that have mutations in the retinoblastoma (Rb) gene. Mutated Rb genes occur in many types of cancer, suggesting that these E2f proteins might offer a safe and novel therapeutic target in these tumors. The findings are published in back-to-back papers in the Dec. 17 issue of the journal Nature.