
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: FRIDAY, October 21, 1994                   TAG: 9410210054
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A4   EDITION: METRO 
SOURCE: CHICAGO TRIBUNE
DATELINE:                                 LENGTH: Medium

DISCOVERY MAY HELP IN CANCER

A new discovery by University of Chicago biologists may help unlock one of the key mysteries of cancer: how malignant cells become ``immortal'' and divide uncontrollably until the body chokes on them.

Daniel Gottschling, associate professor of molecular genetics and cell biology, reported Thursday in the journal Science that he and a colleague had identified the gene responsible for the suspected immortalizing agent in cancer cells.

The gene produces an enzyme called telomerase that normally adds genetic material to the endcaps, or telomeres, of chromosomes of sperm and egg cells to keep them young and vigorous as they divide.

The endcaps prevent chromosomes, the repositories of genes, from being joined together or chewed up and rearranged by other chemical reactions inside the cell.

Scientists think body cells, which apparently lack the telomerase enzyme, stop dividing and die off appropriately after 50 to 100 divisions when their telomeres get worn down to the nub.

Gene hunters have long considered the farthest chromosomal tips, the telomeres, a nightmare dotted by endless random DNA repeats and gene detritus deposited eons ago by foreign viruses. But recently has come the realization that the long chains may serve as a kind of biological clock that monitors the natural lifespan of cells.

``The lack of telomerase results in the telomeres shrinking, which provides a way for the cells to mark time and age every time they divide.''

Recently, scientists discovered the enzyme actively being produced in cancer cells, a place it had no business being. That led them to suspect that telomerase somehow had become reactivated in malignancy and caused the telomeres to begin growing again.

Hence, a new cancer theory: If telomere length is a cell's way of knowing when to die, and if in a tumor cell the length stays the same with each cell division because of telomerase, the cancer cell may continue dividing merely because nothing tells it to stop.

That makes telomerase a tantalizing target for new anti-cancer drugs.

by CNB