Cancer Cells Don't Age!
JOURNAL WATCH
Copyright 1988 Massachusetts Medical Society. All rights
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9/25/90
7. UNRAVELING THE BIOLOGY OF CELLULAR AGING
We grow old because our cells grow old -- a process we think of as
inevitable and immutable.
Cancer cells, however, seem to escape the process of aging and
become "immortal." This review of recent research sheds some light
on the cellular aging process and suggests a connection between the
biology of cellular aging and the biology of cancer.
Investigators have observed that a human diploid fibroblast placed
in a cell culture goes through a limited, predictable number of
replications before it stops dividing.
Moreover, the replicative life span of an animal's fibroblasts has
been shown to correlate with the life span of the species. When a
fibroblast becomes senescent, its growth is stopped at a particular
part of the cell cycle (the G1/S boundary) and it ceases to respond
to certain growth factors.
Certain growth-inducing proto-oncogenes seem to be turned off, while
concentrations of possibly growth-retarding proteins seem to be
increased.
Researchers speculate that cancer cells circumvent the mechanisms of
senescence, and experiments have shown that specific molecular
manipulations can cause a senescent cell to begin dividing again.
It remains to be shown whether further understanding of cellular
aging will have implications for the control of aging in plants and
animals, but the prospect is exciting. -- ALK.
Goldstein S.
Replicative senescence: the human fibroblast comes of age.
Science 1990 Sep 7; 249:1129-33
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