Cancer Cells With No Future

WASHINGTON, D.C.--Scientists have discovered a gene that destines certain cancer cells to a limited lifetime. Experts hope that the finding, reported here this week at the American Society for Cell Biology's annual meeting, could eventually lead to a new kind of gene therapy for cancer.

Most human adult cells are quiescent, which means they have stopped dividing, after having received certain biochemical signals. But even without those signals, most cells would eventually stop dividing on their own, reaching a permanent kind of quiescence called "senescence." Cancer cells disregard signals to become quiescent, and many types never reach senescence. They're called immortal, because in theory they could go on dividing forever.

Using a painstaking combination of trial and error and standard genetic techniques, gerontologist Olivia Pereira-Smith and her colleagues at the Baylor College of Medicine in Houston, Texas, have now found a gene that ends immortality in one of the four classes of immortal cells. They used cell lines from brain and cervical cancer. Based on its sequence, the group says the gene may encode a transcription factor, a protein that controls expression of other genes--perhaps those that give cells a limited lifetime.

The finding "is going to give us insights into the whole process of [cellular] immortality," says Harvey Ozer, a molecular and cell biologist at the New Jersey Medical School in Newark, because this is the first time researchers have found a gene involved in the process. The gene might someday be used to treat cancer, Ozer says. "If you were to figure out a way of introducing a normal version of this [gene] into a [patient's] cancer cell, you might stop it from growing."

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