beltman713
06-09-2005, 04:09 PM
http://www.msnbc.msn.com/id/8135713/
Scientists Find Key to Stem Cell "Immortality"
MicroRNAs short-circuit
cellular ‘stop signals’
By Alan Boyle
Science editor
MSNBC
Updated: 9:26 p.m. ET June 8, 2005
One of the medical marvels of stem cells is that they continue to divide and renew themselves when other cells would quit. But what is it that gives stem cells this kind of immortality?
Researchers report in the journal Nature that microRNAs — tiny snippets of genetic material that have now been linked to growth regulation in normal cells as well as cancer growth in abnormal cells — appear to shut off the "stop signals" or brakes that would normally tell cells to stop dividing.
"What we think we see is that there is a special mechanism to get rid of the brakes," said University of Washington biochemist Hannele Ruohola-Baker, a leading member of the research team.
Stem cells have been the focus of intense research interest because of their role in regenerating all the body's tissue types, from blood cells to brain cells. MicroRNAs could conceivably be harnessed to give a boost to aging stem cells, or even add some of the qualities of stem cells to more ordinary types of cells, Ruohola-Baker told MSNBC.com.
Link to cancer
Too much of the wrong kinds of microRNAs could be a bad thing: In fact, three other studies in Thursday's issue of Nature linked certain combinations of microRNAs to cancer:
* One team of researchers reported that a cluster of microRNAs can cause blood cancer in mice, and was also apparently linked to a variety of human tumors.
* Another found that some microRNAs cooperate with a gene known as c-Myc that is already known to cause human cancers.
* The third team found that different human cancers have different microRNA signatures — suggesting that doctors might someday use microRNA profiles to diagnose human tumors.
In a commentary, Dr. Paul Meltzer of the National Human Genome Research Institute said microRNAs "are now definitely linked to the development of cancer." But one of the researchers involved in the c-Myc study, Dr. Chi Dang of the Johns Hopkins Kimmel Cancer Center, emphasized that microRNAs can have a beneficial as well as a detrimental effect on cell function.
"Whether too much or too little of these or other microRNAs is a good thing or a bad thing — whether it would contribute to or help prevent cancer — depends on their targets in the cell," he said in a Johns Hopkins news release.
Scientists Find Key to Stem Cell "Immortality"
MicroRNAs short-circuit
cellular ‘stop signals’
By Alan Boyle
Science editor
MSNBC
Updated: 9:26 p.m. ET June 8, 2005
One of the medical marvels of stem cells is that they continue to divide and renew themselves when other cells would quit. But what is it that gives stem cells this kind of immortality?
Researchers report in the journal Nature that microRNAs — tiny snippets of genetic material that have now been linked to growth regulation in normal cells as well as cancer growth in abnormal cells — appear to shut off the "stop signals" or brakes that would normally tell cells to stop dividing.
"What we think we see is that there is a special mechanism to get rid of the brakes," said University of Washington biochemist Hannele Ruohola-Baker, a leading member of the research team.
Stem cells have been the focus of intense research interest because of their role in regenerating all the body's tissue types, from blood cells to brain cells. MicroRNAs could conceivably be harnessed to give a boost to aging stem cells, or even add some of the qualities of stem cells to more ordinary types of cells, Ruohola-Baker told MSNBC.com.
Link to cancer
Too much of the wrong kinds of microRNAs could be a bad thing: In fact, three other studies in Thursday's issue of Nature linked certain combinations of microRNAs to cancer:
* One team of researchers reported that a cluster of microRNAs can cause blood cancer in mice, and was also apparently linked to a variety of human tumors.
* Another found that some microRNAs cooperate with a gene known as c-Myc that is already known to cause human cancers.
* The third team found that different human cancers have different microRNA signatures — suggesting that doctors might someday use microRNA profiles to diagnose human tumors.
In a commentary, Dr. Paul Meltzer of the National Human Genome Research Institute said microRNAs "are now definitely linked to the development of cancer." But one of the researchers involved in the c-Myc study, Dr. Chi Dang of the Johns Hopkins Kimmel Cancer Center, emphasized that microRNAs can have a beneficial as well as a detrimental effect on cell function.
"Whether too much or too little of these or other microRNAs is a good thing or a bad thing — whether it would contribute to or help prevent cancer — depends on their targets in the cell," he said in a Johns Hopkins news release.