Biochemists Find How Cells ‘Die’ in Renewal Process

Biochemists have identified a pathway that cells use to commit suicide, an advance that promises developments in treating cancer, stroke and a multitude of other diseases.

Programmed cell death, or apoptosis, is necessary for the body to develop and function properly. In developing embryos, the cells of early stages must die to make room for those that come along later. In adults, cells constantly turn over, so the old ones must die to make room for the ones that are replacing them.

When old cells won’t die, cancer can result. Researchers hope that a better understanding of cell death will lead to better ways to fight the disease and others that result from malfunctions in apoptosis.

Biochemist Xiaodong Wang has contributed to that effort over the last two years by identifying the chemical signals that tell a cell it’s time to die. In a paper published Nov. 13 in the journal Cell, he describes the chain of commands in full.

“I think this is going to have a lot of broad ramifications for a lot of diseases,” said David Fisher of the Dana Farber Cancer Institute.

Wang and six colleagues described how a molecule known as cytochrome c, when let loose in a cell, dooms it. Cytochrome c signals another molecule, known as Apaf-1, and that sets off a molecular chain reaction that ends in self-destruction.

Knowing every link in that chain gives researchers the opportunity to block it. That might be helpful in treating Lou Gehrig’s disease and other conditions in which programmed cell death happens when it shouldn’t.

The knowledge may also help researchers devise a way to stimulate apoptosis when it stops. That’s what happens in many cases of cancer.