ANN ARBOR, Mich.---Like a sentry guarding the castle walls, a molecular messenger inside adult stem cells sounds the alarm when it senses hazards that could allow the invasion of an insidious enemy: Cancer.
The alarm bell halts the process of cell division in its tracks, preventing an error that could lead to runaway cell division and eventually, tumor formation.
"Our work suggests that to be able to prevent abnormal cell proliferation, which could lead to cancer, stem cells developed this self-checking system, what we're calling a checkpoint," said Yukiko Yamashita of the University of Michigan's Life Sciences Institute.
"And if it looks like the cell is going to divide in the wrong way, the checkpoint senses there's a problem and sends the signal: 'Don't divide! Don't divide!'" said Yamashita, a research assistant professor of life sciences and an assistant professor of cell and developmental biology at the U-M Medical School.
The mechanisms which the body has for protecting against cancers are problematic for the development of stem cell therapies. Our stem cells become less able to divide as they age. Research done in mice shows that blood in the aged contains compounds that suppress stem cells. Maybe some of the factors that stop the cell division mentioned above are coming from the blood or surrounding tissues. We need to understand in detail each of the mechanisms by which stem cells become less able to divide with age.
Stem cells can be genetically engineered to ignore some of the factors that suppress stem cell replication. But this approach seems problematic. Aging isn't the only cause of the body's production of compounds that suppress growth. Stem cells that ignore growth suppression signals might cause problems similar to those caused by cancers.
|Share |||Randall Parker, 2008 October 23 12:31 AM Biotech Stem Cells|