Sangamo's Zinc Finger Nuclease Technology Used to Efficiently Modify Human Stem Cells

Tue Sep 8, 2009 7:00am EDT

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Sangamo's Zinc Finger Nuclease Technology Used to Efficiently Modify Human
Stem Cells
Novel Approach Enables Breakthrough in Human Stem Cell Manipulation for
Medical Research and for the Development of Stem Cells as Therapeutics

RICHMOND, Calif., Sept. 8 /PRNewswire-FirstCall/ -- Scientists from The
Whitehead Institute used zinc finger nucleases (ZFNs) designed by Sangamo
BioSciences, Inc., (Nasdaq: SGMO) to efficiently and precisely modify the
genomes of human embryonic stem cells (hESCs) and induced pluripotent stem
cells (hiPSCs). Human ESCs and iPSCs are useful tools in drug discovery and
development.  Scientists also hope to use these cells therapeutically in
transplantation medicine and other regenerative applications. The research was
described in a paper which appears in today's issue of the scientific journal
Nature Biotechnology.

"The application of ZFN technology to human stem cells opens a new phase in
human genetics," said Rudolf Jaenisch, M.D., a member of the Whitehead
Institute and Professor of Biology at Massachusetts Institute of Technology
(MIT). "In contrast to mouse stem cells which have been easy to modify, it has
been very difficult and time-consuming to modify genes in human ESCs and
iPSCs.  This has severely limited their usefulness for the study of cell
differentiation and as models for human disease.  The work that our team
published in Nature Biotechnology demonstrates that ZFNs enable new, rapid,
efficient and specific methods to work with stem cells giving researchers the
tools to gain valuable insights into how embryonic stem cells differentiate
into adult cells and enabling the generation of patient-specific models of
human disease."

Stem cells differ from other cell types in two fundamental ways. First, they
are unspecialized cells capable of renewing themselves through cell division.
Second, under certain conditions, they can be induced to become tissue- or
organ-specific cells with special functions.  Stem cells have the potential to
develop into the body's many different cell types and in many tissues they
serve a repair function, differentiating and replacing damaged cells.  iPSCs
are adult cells that have been genetically reprogrammed to an embryonic stem
cell-like state. An advantage of iPSCs is that they can be derived from the
adult cells of a person and will possess the same genetic background as that

"These data are another powerful demonstration of the specificity and broad
applicability of Sangamo's ZFP technology across medically and commercially
relevant cell types," stated Philip Gregory, D. Phil., Sangamo's chief
scientific officer and vice president of research.  "The ability to
efficiently modify stem cells enables the generation of valuable new tools for
drug screening and the study of human disease as well as therapeutic
applications in regenerative medicine."

In the article published today, Dr. Jaenisch and his team demonstrated the
broad applicability of gene editing applications enabled by ZFNs in hESCs and
hiPSCs.  In one example, they generated hESCs that carried a reporter gene. 
This gave researchers a visual method to clearly identify undifferentiated
cells from those that had differentiated to their final cell type.  In another
example they inserted a new gene into a specific site in the genome of hESCs
and demonstrated that ZFNs can be used to generate reporter cells in
non-expressed genes in the genomes of hESCs and iPSCs, tools that will be
useful in the study of cell fate and differentiation protocols.  

("Efficient Targeting of Expressed and Silent Genes in Human ESCs and iPSCs
Using Zinc Finger Nucleases" D.Hockemeyer, Soldner, F., Beard, C., Gao, Q.,
Mitalipova, M., DeKelver, R. C., Katibah,  G.E., Amora, R., Boydston, E.A.,
Zeitler, B., Meng, X., Miller, J.C., Zhang, L., Rebar, E.J., Gregory, P.D,
Urnov, F.D., and Jaenisch, R. Nature Biotechnology (2009) Vol 27:September)

About Sangamo Biosciences, Inc.
Sangamo BioSciences, Inc. is focused on the research and development of novel
DNA-binding proteins for therapeutic gene regulation and modification.  The
most advanced ZFP Therapeutic(TM) development program is currently in Phase 2
clinical trials for evaluation of safety and clinical effect in patients with
diabetic neuropathy and ALS. Sangamo also has a Phase 1 clinical trial to
evaluate safety and clinical effect of a ZFP Therapeutic approach for the
treatment of HIV/AIDS. Other therapeutic development programs are focused on
cancer, neuropathic pain, nerve regeneration, Parkinson's disease and
monogenic diseases.  Sangamo's core competencies enable the engineering of a
class of DNA-binding proteins known as zinc finger DNA-binding proteins
(ZFPs).  By engineering ZFPs that recognize a specific DNA sequence Sangamo
has created ZFP transcription factors (ZFP TF) that can control gene
expression and, consequently, cell function.  Sangamo also is developing
sequence-specific ZFP Nucleases (ZFN) for gene modification.  Sangamo has
established strategic partnerships with companies in non-therapeutic
applications of its technology including Dow AgroSciences, Sigma-Aldrich
Corporation and several companies applying its ZFP technology to engineer cell
lines for the production of protein pharmaceuticals. For more information
about Sangamo, visit the company's web site at

This press release may contain forward-looking statements based on Sangamo's
current expectations. These forward-looking statements include, without
limitation, references to the application of Sangamo's ZFN technology. Actual
results may differ materially from these forward-looking statements due to a
number of factors, including technological challenges, the ability of Sangamo
and its partners to develop commercially viable products and technological
developments by Sangamo's competitors.  See the company's SEC filings, and in
particular, the risk factors described in the company's Annual Report on Form
10-K and its most recent quarterly report on Form 10-Q. Sangamo assumes no
obligation to update the forward-looking information contained in this press

SOURCE  Sangamo BioSciences, Inc.

Elizabeth Wolffe, Ph.D.,, +1-510-970-6000 x271
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