Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers pinpoint a new enemy for tumor-suppressor p53

30.06.2009
Researchers at The University of Texas M. D. Anderson Cancer Center have identified a protein that marks the tumor suppressor p53 for destruction, providing a potential new avenue for restoring p53 in cancer cells.

The new protein, called Trim24, feeds p53 to a protein-shredding complex known as the proteasome by attaching targeting molecules called ubiquitins to the tumor suppressor, the team reported this week in the Proceedings of the National Academy of Sciences Online Early Edition.

"Targeting Trim24 may offer a therapeutic approach to restoring p53 and killing tumor cells," said senior author Michelle Barton, Ph.D., professor in M. D. Anderson's Department of Biochemistry and Molecular Biology.

The discovery is based on an unusual approach to studying p53, which normally forces potentially cancerous cells to kill themselves and is shut down or depleted in most human cancers. Studies of the p53 protein and gene tend to focus on cancer cell lines or tumors, where the dysfunction already is established, Barton said. "We wanted to purify p53 from normal cells to better understand the mechanisms that regulate it."

The team developed a strain of mice with a biochemical tag attached to every p53 protein expressed. After first assuring that the tagged p53 behaved like normal p53, the team then used the tag, or hook, to extract the protein. "We could then identify proteins that were attached to p53, interacting with it, through mass spectrometry," Barton said.

They found Trim24, a protein previously unassociated with p53 that is highly expressed in tumors and is a target of two known oncogenes in distinct forms of leukemia and thyroid cancer.

Subsequent experiments showed that decreased levels of Trim24 led to increased levels of p53 expression in the cell nucleus, and increasing Trim24 expression reduced p53 levels. Loss of Trim24 expression in a breast cancer cell line caused spontaneous programmed cell death - apoptosis. A similar response was confirmed in human lung, colon and prostate cancer cells.

Treating cells with a proteasome inhibitor also led to increased p53 expression. Removing an important binding domain of Trim24 or depleting it completely both led to greatly reduced ubiquitin targeting of p53.

An analogous system in fruit flies showed that a simpler version of Trim24 in the flies plays a similar role regulating p53, demonstrating that the relationship is evolutionarily conserved.

Co-authors with Barton are first author Kendra Allton, Abhinav Jain, Ph.D., Hans-Martin Herz, Ph.D., Wen-Wei Tsai, Ph.D., Andres Bergmann, Ph.D., and Randy Johnson, Ph.D., all of M. D. Anderson's Department of Biochemistry and Molecular Biology; and Sung Yun Jung, Ph.D., and Jun Qin, Ph.D., of the Department of Molecular and Cellular Biology at Baylor College of Medicine. Allton completed the paper as her master's degree thesis for The University of Texas Graduate School of Biomedical Sciences, a joint program of M. D. Anderson and The University of Texas Health Science Center at Houston. Allton, Jain, Tsai, Johnson and Barton also are with M. D. Anderson's Center for Stem Cell and Developmental Biology.

Funding for the project was provided by M. D. Anderson's Kleberg Fund for Innovative Research, grants from the National Institutes of Health, CellCentric, Ltd., the Kadoorie Foundation, the Welch Foundation, the National Cancer Institute and the Laura and John Arnold Foundation Odyssey Fellowship (for Abhinav Jain).

About M. D. Anderson

The University of Texas M. D. Anderson Cancer Center in Houston ranks as one of the world's most respected centers focused on cancer patient care, research, education and prevention. M. D. Anderson is one of only 40 comprehensive cancer centers designated by the National Cancer Institute. For four of the past six years, including 2008, M. D. Anderson has ranked No. 1 in cancer care in "America's Best Hospitals," a survey published annually in U.S. News & World Report.

Scott Merville | EurekAlert!
Further information:
http://www.mdanderson.org

More articles from Life Sciences:

nachricht New catalyst controls activation of a carbon-hydrogen bond
21.11.2017 | Emory Health Sciences

nachricht The main switch
21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

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

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>