cellular mutation and cancer - or lack thereof.

[Zack Clayton <zclayton@YAHOO.COM>]

I just wonder what this news means for radiological cancer induction

and the LNT?  Cellular mutations apparently DON'T cause cancer by

themselves.



http://www.sciencedaily.com/releases/2003/06/030604084515.htm



Source:  

St. Jude Children's Research Hospital



Date:  

2003-06-04

 

Cloning Embryos From Cancer Cells



MEMPHIS, TENN. (June 3, 2003) -- Nuclei removed from mouse brain tumor

cells and transplanted into mouse eggs whose own nuclei have been

removed, give rise to cloned embryos with normal tissues, even though

the mutations causing the cancer are still present. This research, from

scientists at St. Jude Children's Research Hospital, appears in the

June 1 issue of Cancer Research.



The finding demonstrates that the cancerous state can be reversed by

reprogramming the genetic material underlying the cancer, according to

James Morgan, Ph.D., a member of the St. Jude Department of

Developmental Neurobiology, and lead author of the study. The findings

also indicate that genetic mutations alone are not always sufficient to

cause a cell to become cancerous.



“Specifically, it shows that so-called epigenetic factors are key

elements in the development and maintenance of tumors,” Morgan said.



Epigenetic factors are those that influence the cell’s behavior.

Examples include environmental effects and chemical modification.



“The concept of epigenetic factors having a role in cancer is already

largely accepted,” Morgan said. “In fact, it’s already known that

epigenetic alterations of chromosomes can cause certain rare forms of

cancer. And some anti-cancer agents actually target epigenetic changes.

But this is the first formal proof of the theory in a living animal.”



Unlike mutations, epigenetic modifications of DNA are potentially

reversible molecular events that cause changes in gene expression. Some

genes that help prevent the development of cancer (e.g., tumor

suppressor genes) can be targets of epigenetic factors. The

inactivation of such a gene might make the DNA more vulnerable to

developing a cancer-causing mutation.



The St. Jude researchers used nuclei from mouse medulloblastoma cells

to create the clones. Medulloblastomas are brain tumors that tend to

spread to the spinal cord. They account for about 20 percent of

childhood brain tumors and most often occur in children under ten years

of age.



The team, led by Morgan and department chair Tom Curran, Ph.D., placed

nuclei from medulloblastoma cells into mouse eggs whose own DNA had

been removed.



“Since the embryos did not develop tumors, we conclude that the

cancerous properties were removed by reprogramming,” Morgan said.



“The use of mouse eggs to reprogram cancer cell DNA represents a new

strategy for investigating the molecular basis of cancer,” Curran said.

“By studying this model we hope to identify which epigenetic factors

may contribute to this form of brain tumor. In addition, it also gives

us a valuable tool for testing new therapies.”



Other authors of the study include Leyi Li, Michele Connelly and

Cynthia Wetmore.



### This work was supported in part by a National Institute of Health

(NIH) Cancer Center Support CORE grant, ALSAC, the Pediatric Brain

Tumor Foundation and NIH grants.



St Jude Children's Research Hospital is internationally recognized for

its pioneering work in finding cures and saving children with cancer

and other catastrophic diseases. Founded by late entertainer Danny

Thomas and based in Memphis, Tenn., St. Jude freely shares its

discoveries with scientific and medical communities around the world.

No family ever pays for treatments not covered by insurance, and

families without insurance are never asked to pay. St. Jude is

financially supported by ALSAC, its fund-raising organization. For more

information, please visit http://www.stjude.org.



Editor's Note: The original news release can be found here.



This story has been adapted from a news release issued by St. Jude

Children's Research Hospital.

 



Zack Clayton

HP III

Columbus, Ohio







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