Geron Announces Publication of Studies Showing That Cells Derived from Human
Embryonic Stem Cells Can Be Immortalized
by Telomerase
MENLO PARK, Calif.--(BUSINESS WIRE)--Nov. 11, 2004--Geron
Corporation (Nasdaq:GERN) announced today the publication of studies
that demonstrate the synergy of Geron's telomerase and human embryonic
stem cell (hESC) technologies to produce immortalized cells for
research, biologics production, and therapeutic applications.
In a report published in the November issue of the journal Stem
Cells, scientists from Geron and the Roslin Institute demonstrated (i)
that fibroblast-like cells could be differentiated from hESCs, (ii)
that those cells could be immortalized with telomerase, and (iii) that
the immortalized cells could then be used to produce conditioned
medium to support feeder-free growth of undifferentiated hESCs.
hESCs are unique, unspecialized stem cells that can be grown in
large quantities and differentiated into a wide variety of cell types
potentially useful for treating a range of human diseases.
Undifferentiated hESCs have unlimited proliferative capacity because
they express the enzyme telomerase. In the course of differentiation,
telomerase is down-regulated and the resulting differentiated cells
have a finite lifespan. In these studies, the researchers derived
fibroblast-like cells, termed HEF1 cells, from hESCs. The
telomerase-negative HEF1 cells underwent senescence after
approximately ten population doublings. Upon insertion of the gene
encoding the catalytic subunit of telomerase in the HEF1 cells, the
cells stably expressed high levels of telomerase activity, showed
continuous growth in culture, and did not senesce. Moreover, the
telomerase-immortalized HEF1 cells still responded to osteogenic
inductive factors and were capable of differentiating into fully
mature osteoblasts (bone-producing cells). These results show that
cells derived from hESCs can be immortalized by insertion of the
telomerase gene without affecting their ability to further
differentiate into functional effector cells.
Geron has previously reported its development of an improved
method for culturing hESCs in medium conditioned by mouse embryonic
fibroblasts (MEFs), instead of on feeder layers of MEFs, thereby
eliminating the need for direct contact with mouse cells. In the new
studies, the telomerase-immortalized HEF1 cells were used to produce
conditioned medium, which was shown to be capable of supporting the
growth of undifferentiated hESCs, including the same hESC line from
which the HEF1 cell was derived. The culture system was thus both
human- rather than mouse-based, and genotypically homogeneous.
"This development further reduces the risk of exposure of hESCs to
potential mouse xenogeneic pathogens," stated Jane S. Lebkowski,
Geron's senior vice president of regenerative medicine. "Moreover, it
allows the production of hESCs in a totally isogenic system where the
conditioned medium is produced by derivatives of the hESCs
themselves."
"Geron has recently been awarded a U.S. patent on feeder-free
cultures for the propagation of human embryonic stem cells," stated
Thomas B. Okarma, Geron's president and chief executive officer. "This
development is one of a series of key technologies developed at Geron
to scalably and economically produce cells safe for therapeutic use.
These results are significant also because they demonstrate that
hESC-derived cells can be immortalized with telomerase, thereby
broadening the possible applications of hESC-derived cell types."
Geron is a biopharmaceutical company focused on developing and
commercializing therapeutic and diagnostic products for cancer based
on its telomerase technology, and cell-based therapeutics using its
human embryonic stem cell technology.
This news release may contain forward-looking statements made
pursuant to the "safe harbor" provisions of the Private Securities
Litigation Reform Act of 1995. Investors are cautioned that such
forward-looking statements in this press release regarding potential
applications of Geron's technologies for the development of
hESC-derived cells constitute forward-looking statements that involve
risks and uncertainties, including, without limitation, risks inherent
in the development and commercialization of potential products, need
for future capital and maintenance of our intellectual property
rights. Actual results may differ materially from the results
anticipated in these forward-looking statements. Additional
information on potential factors that could affect our results and
other risks and uncertainties are detailed from time to time in
Geron's periodic reports, including the quarterly report on Form 10-Q
for the quarter ended September 30, 2004.
--30--MCC/sf*
CONTACT: Geron Corporation
David L. Greenwood, 650-473-7765
KEYWORD: CALIFORNIA
INDUSTRY KEYWORD: BIOTECHNOLOGY MEDICAL PHARMACEUTICAL PUBLISHING
PRODUCT
SOURCE: Geron Corporation
Copyright Business Wire 2004
Nov-11-2004 12:30 GMT
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