GERN NEWS!
Geron Announces First In Vivo Data Indicating Telomerase Expression in Normal
(Business Wire 12/28 18:22:19)
Human Cells Extends Their Replicative Lifespan Without Oncogenic Transformation
Business/Health and Medical Writers
MENLO PARK, Calif.--(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
cancer.
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 cardiovascular diseases.
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. |
