Telomerase Expression in Human Cells!
tmatth at netcom.ca
Mon Dec 28 23:33:16 EST 1998
Geron Announces First In Vivo Data Indicating Telomerase Expression in
Normal Human Cells Extends Their Replicative Lifespan Without Oncogenic
MENLO PARK, CALIF. (Dec. 28) BW HEALTHWIRE -Dec. 28, 1998--Geron
Corporation (Nasdaq:GERN) and the University of Texas Southwestern
Medical Center at Dallas announced today the publication of two papers
in the Jan. 1, 1999, issue of Nature Genetics demonstrating that
telomerase expression in normal cells confers an infinite replicative
capacity, but does not result in cellular changes associated with
These findings have important implications for scientific research as
well as pharmaceutical drug discovery and product development.
Telomerase is an "immortalizing" enzyme that imparts infinite
replicative capacity to reproductive and cancer cells. Conversely,
normal somatic cells that do not express telomerase have a finite
replicative capacity and eventually senesce. Senescent cells can damage
surrounding tissues, contributing to age-related pathologies. For
example, senescent skin fibroblasts can contribute to slower healing
and wrinkling. Similarly, senescent retinal pigment epithelial cells
can contribute to age-related macular degeneration.
Research published Jan. 16, 1998, in Science (by the same two research
teams making today's announcement) demonstrated that the introduction
of telomerase into normal cells resulted in the extension of their
replicative lifespan. The two papers announced today provide new in
vitro and the first in vivo data demonstrating that telomerase
expression in normal cells results in cellular immortality but does not
induce cancer-associated physical and biochemical characteristics.
Specifically, the Geron researchers report that human skin fibroblasts
and retinal pigment epithelial cells transfected with telomerase over a
year ago have been continually dividing and can therefore now be
considered immortal. Moreover, these same cells retain normal growth
control and do not form tumors in vivo, even after twice the normal
maximum number of population doublings. The University of Texas
Southwestern Medical Center researchers report that the expression of
telomerase in human fibroblasts is sufficient in vitro to extend their
replicative capacity three times beyond when they would normally
senesce without malignant transformation.
According to Dr. Calvin Harley, Geron's chief scientific officer,
"These findings and similar results from others to whom we have given
the telomerase gene, increase our confidence that `telomerizing' normal
human cells will prove useful in research, genetic engineering, drug
discovery, and treating disease".
Geron believes that being able to generate an essentially unlimited
supply of normal human cells will create new opportunities to study
basic mechanisms of cell growth and differentiation, and as a result
provide a reproducible source of young normal cells for both drug
screening and testing as well as cell and gene therapy. For example,
telomerase could be used to extend the limited lifespan of blood vessel
forming cells, the shortage of which has prevented their widespread use
for discovery of new treatments for hypertension and other
The ability to increase and potentially regulate the lifespan of normal
cells should also help overcome a major hurdle in genetic engineering
and cell and gene therapies. For example, it is now known that the
isolation, expansion, and manipulation of cells outside the body for
reimplantation into patients causes accelerated aging of the cells.
The use of `telomerized' cells with an extended lifespan should enable
the cells to survive longer in the body. Finally, for therapeutic
applications, Geron will seek to use regulated telomerase expression to
postpone or reverse senescence and age-related pathologies such as
macular degeneration, skin atrophy, and atherosclerosis.
Telomerase is actually a complex of at least two distinct molecules,
one made of RNA and another made of protein. These two molecules are
necessary for making active telomerase. Geron owns or co-owns issued
patents with claims on both these molecules as well as their use in
research, diagnostics and therapeutics.
Senior author of the Geron Nature Genetics paper, "Telomerase
Expression in Human Somatic Cells does not Induce Changes Associated
with a Transformed Phenotype," is Dr. Choy-Pik Chiu at Geron.
Co-authors at Geron include Xu-Rong Jiang, Edwin Chang, Maria Frolkis,
Brenda Kusler and Andrea Bodnar. The work reported in this paper was
done in collaboration with Dr. Geoffrey M. Wahl at the Salk Institute
and Dr. Thea Tlsty at the University of California, San Francisco.
Geron Corporation is a biopharmaceutical company focusing on
discovering and developing therapeutic and diagnostic products based
upon the company's understanding of human embryonic stem cells, and of
telomeres and telomerase in cells -- fundamental biological platforms
underlying cancer and other age-related degenerative diseases.
The company desires to take advantage of the "safe harbor" provision of
the Private Securities Litigation Reform Act of 1995. Specifically, the
company wishes to alert readers that the matters discussed in this
press release may constitute forward-looking statements that are
subject to certain risks and uncertainties. Actual results may differ
materially from the results anticipated in these forward-looking
statements. Additional information on potential factors that could
affect the company's results is included in the company's quarterly
report on Form 10-Q for the quarter ended September 30, 1998.
To receive an index and copies of recent press releases, call Geron's
News On Demand toll-free fax service, 1-800-782-3279. Additional
information about the company can be obtained at www.geron.com.
CONTACT: Geron Corporation
Nancy Robinson, 650-473-7765 (Investor & Media Relations)
Mike Jackman, 415/388-3216 (Media)
Lisa Burns or John Nugent, 212/213-0006 (IR)
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