Stem and cancer cells have something in common
Shared protein patrols cell proliferation.
30 December 2002
KENDALL POWELL
The same protein may control the proliferation of stem cells and cancer cells, according to a new study1.
The finding will help researchers understand how both types of cell can divide indefinitely. But it also highlights concerns that stem cell transplants could run the risk of seeding cancers.
The discovery should help scientists manipulate stem cells to give an unlimited source for use in medicine, says Robert Tsai at the National Institute of Neurological Disorders and Stroke in Bethesda, Maryland. The hope is that stem-cell therapy will one day be able to replace or repair any damaged tissue in the body.
To do this, scientists must be able to control proliferation so that transplanted cells don't become cancerous. More researchers should be "paying attention to the molecular events that take part in the earliest stages of stem cells," says Julia Polak, director of Imperial College London's Tissue Engineering and Regenerative Medicine Centre.
The body normally maintains the ability of certain stem cells to renew themselves so that they can replace cells that wear out. Cancer cells hijack this property to transform into dividing tumours. The molecular link now established between stem cells and cancer cells "is something novel, as far as I'm aware," says Polak.
Tsai, and his colleague Ronald McKay showed that the protein nucleostemin is abundant in self-renewing cells such as mouse embryonic and neural stem cells and several human cancer cell lines.
By contrast, the protein is scarce in cells that have grown into a mature cell type and can no longer divide. Increasing or knocking down the level of nucleostemin in neural stem cells and cancer-like cells in the lab reduced their proliferation.
Although the exact function of nucleostemin is not yet known, it appears to behave like a molecular switch to control cell division. The researchers also showed that it binds to a protein called p53, which regulates cell proliferation and is implicated in many cancers.
References
1. Tsai, R. Y. L. & McKay, R. D. G. A nucleolar mechanism controlling cell proliferation in stem cells and cancer cells. Genes &Development, 16, 2991 - 3003, (2002). |Article|
© Nature News Service / Macmillan Magazines Ltd 2002 |
