Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Potential ’weak link’ between virus and liver cancer discovered

22.07.2005


Researchers at The University of Texas M. D. Anderson Cancer Center have uncovered a crucial molecular link between a viral infection and development of a common and fatal form of liver cancer. In the process, they have identified a possible way to treat this disease as well as a number of other cancers.



In findings reported in the journal Molecular Cell, the researchers traced the pathway by which the hepatitis B virus (HBV) leads to development of hepatocellular carcinoma (HCC) and found that it "turns off" an enzyme known as GSK-3ß, which acts to suppress tumor formation as well as inhibit the spread of cancer.

GSK-3ß could prove to be the Achilles heel for liver cancer and other tumors - including breast, colon, kidney and stomach - that use a similar "pathway" to cancer development, the researchers say.


"This study identified a novel mechanism for how hepatitis B primes liver cells to turn cancerous, and what we found has potential relevance for other cancers as well," says the study’s lead author Mien-Chie Hung, Ph.D., professor and chair of the Department of Molecular and Cellular Oncology. Hung collaborated with a team of researchers that included scientists from Baylor College of Medicine in Houston, Germany, Taiwan and China.

Infection from HBV is widespread throughout the world, especially in developing nations, and is considered by the World Health Organization (WHO) to be a serious global health problem. The virus, transmitted by blood or body fluids, is up to 100 times more infectious than HIV (human immunodeficiency virus).

Of the 2 billion people who have been infected with HBV, more than 350 million have chronic, or lifelong, infections that put them at high risk of death from cirrhosis of the liver and liver cancer, according to WHO. These diseases kill about one million people worldwide each year.

"HCC accounts for up to 90 percent of all liver cancers, and individuals who carry the hepatitis B virus have a greater than 100-fold increased relative risk of developing HCC," Hung says. "Many researchers have been working to understand how the virus causes this cancer so that potential treatments can be designed."

Scientists have long linked development of HBV to HCC, the most common form of liver cancer. They also believe that this cancer is due to activation of a signaling pathway that includes a protein known as beta catenin. When this protein functions normally, it sits on the outside surface of a cell and helps the cell stick to others like it in a tissue, but when it is found inside the cell’s cytoplasm or nucleus, it works to turn on genes involved in cancer development. In the study, 50 percent to 70 percent of all HCC tumors showed an abnormal accumulation of this "oncoprotein" within the cell, Hung says.

What Hung and his team of researchers investigated was just how HBV results in accumulation and activation of the beta catenin oncoprotein. To do that, Qingqing Ding, M.D., a postdoctoral fellow in Hung’s lab, initiated experiments to investigate the chain of molecular events that links how HBX, a gene encoded by HBV virus, "upregulates" beta catenin.

What they found is that HBX shuts down GSK-3ß, whose role is to degrade the beta catenin proteins that enter the interior of a cell. Therefore, GSK-3ß functions as a tumor suppressor, and when it is inactive, beta catenin accumulates in the cell cytoplasm and nucleus. They also resolved a puzzle regarding the relationship between GSK-3ß and Erk, a well-known enzyme frequently activated in human cancers. Erk interacts with and phosphorylates GSK-3ß at a specific amino acid residue Thr 43, resulting in degradation and thus inactivation of GSK-3ß.

"When GSK-3ß becomes inactive, then beta catenin is over-expressed," Hung says. "This is important because beta catenin over-expression is found in many cancer types."

But Hung says the investigators found "a way to turn this around." In current research, they have created a super-active mutant of the GSK-3ß gene at amino acid residue Thr 43. By adding this gene into liver cancer cells, over-expression of beta catenin was downregulated, therefore, proliferation of cancer cells will be inhibited. Based on this finding, "we think it may be possible in the near future to develop novel therapeutic approaches for treatment of the aforementioned cancers including development of gene therapy and a small molecule that will activate GSK-3ß," he says.

Nancy Jensen | EurekAlert!
Further information:
http://www.mdanderson.org

More articles from Studies and Analyses:

nachricht The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

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,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

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

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>