Cell Suicide Prevented by Survival Signals

October 29, 1998—As most cells age or become damaged, a genetic program triggers their self-destruction. This "programmed" cell death performs a critical housekeeping function that prevents damaged, malfunctioning or misplaced cells from causing future harm.

In some instances, however, the death sentence is commuted and certain cells cheat death. How this happens is still largely a mystery, but recent findings from the laboratory of Hermann Steller, an HHMI investigator at the Massachusetts Institute of Technology, may offer new insight. In the October 29, 1998, issue of the journal Cell, Steller's team defines a precise molecular target that allows cells from the fruit fly Drosophila to survive in the presence of death-inducing stimuli.

For the last several years, influential researchers such as Martin Raff of the Medical Research Council Laboratory for Molecular Cell Biology at University College in London, have advanced the idea that the survival of all cells is governed by "social controls" that exert their effects via extracellular signals. An extreme view of social control, noted by Raff in a 1992 Nature review article, is the notion that "just as a cell seems to need signals from other cells in order to proliferate, so it needs signals from other cells in order to survive."

"It seems that cell survival and cell death are subject to the same kinds of social controls that operate on cell proliferation; yet compared with the control of cell proliferation, relatively little is known about the control of cell survival," writes Raff in Nature.

Cancer cells provide one of the best examples of this theory in action, says Steller. "At some point during tumorigenesis, every cancer cell achieves some independence from extracellular survival factors, that is, it escapes the 'soci
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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
29-Oct-1998