>H SCI: New Telomerase Research

John D. Gleason (gleasojb@bc.edu)
Tue, 13 Jan 1998 14:30:41 -0500 (EST)

It looks like telomerase may be the fountain of youth after all!

from http://www.eurekalert.org/releases/extendhum-cell.html

For Immediate Release: 13 January 1997
Embargo Lifted at 13:15:00 ET US

Contact: Heather Stieglitz
(214) 648-3404
University of Texas Southwestern Medical Center

Note to media: photos and illustrations are available upon request

Scientists Extend The Life Span Of Human Cells

DALLAS -- Jan. 13, 1998 -- Researchers at UT Southwestern Medical Center
at Dallas and their colleagues at Geron Corp., Menlo Park, Calif., say
they have figured out how to overcome the mechanisms that control cellular
aging and extend the life span of human cells.

In the Jan. 16 issue of Science, Drs. Woodring Wright and Jerry Shay, UT
Southwestern professors of cell biology and neuroscience, and their
collaborators report finding that the enzyme telomerase -- which UT
Southwestern scientists call a "cellular fountain of youth" -- causes
human cells grown in the laboratory to retain their "youth" and continue
to divide long past the time when they normally stop dividing.

Normal human cells have a limited capacity to proliferate. After a certain
finite number of cell divisions, time on the biological clock runs out;
the cells "age" and stop dividing. Time remaining in a cell's life
correlates with the length of the telomeres -- repeated sequences of DNA
on the ends of chromosomes that protect the tips from degradation. In
normal cells, telomeres shorten with each cell division. Although some
have thought that this telomere shortening might be the biological clocks
control mechanism, the hypothesis was controversial. The research now
proves that human cells grow older each time they divide because their
telomeres shorten.

Specialized reproductive cells and most cancer cells appear to divide
indefinitely. They contain the enzyme telomerase, which adds back
telomeric DNA to the ends of chromosomes. Most normal cells do not have
this enzyme.

"We have found that cellular aging can be bypassed by the introduction of
the catalytic component of the immortalizing enzyme telomerase," Shay
said. "The expression of telomerase LIFE SPAN -- 2in normal human cells
should extend their lifespan indefinitely. From a basic research point of
view, we could begin to replace the abnormal tumor-cell lines now being
used to study biochemical and physiological aspects of growth and
differentiation with normal, yet immortal cell lines."

The scientists introduced telomerase into normal human cells to see if the
cells' life spans could be prolonged. The cells with telomerase extended
the length of their telomeres, divided for 20 additional generations past
the time they normally would stop dividing and are continuing to divide.
The cells also grew and divided in a normal manner, giving rise to normal
cells with the normal number of chromosomes. By all accounts these cells
had found their fountain of youth.

"The extension of normal cell lifespan in a youthful state by telomerase
is a dramatic confirmation of the telomere hypothesis and one that
presents numerous opportunities for biotechnology and medicine," said Dr.
Calvin Harley, Geron vice president and chief scientific officer.

One immediate use of finding that telomere shortening controls cellular
aging may be in the area of producing engineered products in human cells.
Instead of using uncharacterized primary human-cell cultures to produce
vaccines or other biological products, one should now be able to produce
products in a re-engineered normal human cell-type that does not change,
Wright said.

"This research raises the possibility that we could take a patient's own
cells, rejuvenate them, then modify the cells as needed and give them back
to the patient to treat a variety of genetic and other diseases," Wright
said. "The potential long-term applications are simply staggering."

Other investigators on the project included Drs. Andrea Bodnar, Maria
Frolkis, Choy-Pik Chiu, Gregg B. Morin, Calvin Harley and Serge
Lichtsteiner of Geron Corp.; and Drs. Michel Ouellette and Shawn Holt,
research fellows in UT Southwestern's Department of Cell Biology and
Neuroscience. The research was funded in part by the National Institutes
of Health.

The investigators' website can be found at:


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