Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stem-cell sentry sounds the alarm to maintain balance between cancer and aging

16.10.2008
Like a sentry guarding the castle walls, a molecular messenger inside adult stem cells sounds the alarm when it senses hazards that could allow the invasion of an insidious enemy: Cancer.

The alarm bell halts the process of cell division in its tracks, preventing an error that could lead to runaway cell division and eventually, tumor formation.

"Our work suggests that to be able to prevent abnormal cell proliferation, which could lead to cancer, stem cells developed this self-checking system, what we're calling a checkpoint," said Yukiko Yamashita of the University of Michigan's Life Sciences Institute.

"And if it looks like the cell is going to divide in the wrong way, the checkpoint senses there's a problem and sends the signal: 'Don't divide! Don't divide!'" said Yamashita, a research assistant professor of life sciences and an assistant professor of cell and developmental biology at the U-M Medical School.

If everything looks OK, the checkpoint allows adult stem-cell division to proceed, providing new cells to replace damaged and worn-out tissues.

Yamashita and her colleagues have not yet identified the molecules that form the checkpoint mechanism. But they've seen it at work in adult stem cells of the fruit-fly testes, so-called germ-line stem cells.

"Aging is too few divisions and cancer is too many divisions, and people have long speculated that some process controls the balance between them," Yamashita said. "We may have found the mechanism that maintains the delicate balance between over-proliferation---which can lead to cancer---and aging."

The team's findings will be published Oct. 15 in the online version of the journal Nature.

If humans possess a similar checkpoint system and if researchers could someday harness it, they could fine-tune the rate of cellular division to control tumor development as well as tissue aging. But Yamashita stressed that no mammal studies of the checkpoint have been undertaken, so talk of potential human applications is highly speculative.

In fruit flies, the checkpoint monitors germ-line stem cells as they're about to divide. It can sense problems that would derail the division process, which is called mitosis.

Under normal conditions, adult stem-cell division creates one new stem cell and one cell committed to develop into a specific tissue type – such as a skin cell, a blood cell or, in this case, a sperm cell. That form of mitosis is called asymmetric division, and it's exactly what stem cells need to maintain a healthy balance between uncommitted and committed cells.

Cell division is controlled in part by the location of a pair of cellular components called centrosomes. They provide the framework that helps direct how chromosomes are distributed between daughter cells during mitosis.

Normally, centrosomes in a dividing stem cell remain perpendicular to an adjoining messenger cell called the hub. Yamashita and her colleagues found that improper orientation of the centrosomes disrupts the mitotic machinery, steering it on a course toward stem-cell over-proliferation and cancer.

The checkpoint mechanism senses when centrosomes are misaligned, then sounds the alarm that stops cell division.

By preventing faulty cell division, the checkpoint helps ward off cancer. But a balance must be struck: If the checkpoint mechanism slows cell division to a trickle, the resulting shortage of new cells will accelerate tissue aging.

"It's a double-edged sword, and both outcomes are bad," she said. "One path leads to cancer and the other leads to aging. And we haven't found a way to avoid aging without getting cancer."

Jim Erickson | EurekAlert!
Further information:
http://www.umich.edu

Further reports about: Aging Alarm Balance Cancer Lead Stem Stem-cell Yamashita centrosomes checkpoint divide fruit flies maintain mechanism sense sounds stem cells tumor formation

More articles from Life Sciences:

nachricht Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel

nachricht Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>