Navigation Links
Team discovers how a cancer-causing bacterium spurs cell death
Date:11/1/2011

CHAMPAIGN, Ill. Researchers report they have figured out how the cancer-causing bacterium Helicobacter pylori attacks a cell's energy infrastructure, sparking a series of events in the cell that ultimately lead it to self-destruct.

H. pylori are the only bacteria known to survive in the human stomach. Infection with H. pylori is associated with an increased risk of gastric cancer, the second-leading cause of cancer-related deaths worldwide.

"More than half the world's population is currently infected with H. pylori," said University of Illinois microbiology professor Steven Blanke, who led the study. "And we've known for a long time that the host doesn't respond appropriately to clear the infection from the stomach, allowing the bacterium to persist as a risk factor for cancer."

The new study, in Proceedings of the National Academy of Sciences, is the first to show how a bacterial toxin can disrupt a cell's mitochondria its energy-generation and distribution system to disable the cell and spur apoptosis (programmed cell death).

"One of the hallmarks of long-term infection with H. pylori is an increase in apoptotic cells," Blanke said. "This may contribute to the development of cancer in several ways." Apoptosis can damage the epithelial cells that line the stomach, he said, "and chronic damage to any tissue is a risk factor for cancer." An increase in apoptotic cells may also spur the hyper-proliferation of stem cells in an attempt to repair the damaged tissue, increasing the chance of mutations that can lead to cancer.

Previous studies had shown that VacA, a protein toxin produced by H. pylori, induces host cell death, Blanke said, "but the mechanism had been unknown."

The VacA protein was known to target the mitochondrion, an organelle that produces chemical energy where it is needed in the cell. In healthy cells, mitochondria fuse to form elaborate energy-generating networks in response to cellular needs. Mitochondria are important to a lot of other cellular processes; most important to Blanke and his colleagues, they regulate cell death.

While studying how a cell responds to infection, the researchers noticed that H. pylori induced mitochondrial fission. Instead of fusing and forming filamentous networks to respond to the cell's energy needs, the mitochondria were breaking into smaller, unconnected organelles.

"Fusion and fission are two dynamic and opposing processes that must be balanced to regulate mitochondrial structure and function," Blanke said. But infection with H. pylori or with purified VacA toxin alone was pushing the mitochondria toward fission.

The researchers found that VacA recruited a host protein, Drp1, to the mitochondria. This protein plays a central role in mitochondrial fission. Further experiments showed that Drp1-mediated fission of the mitochondrial networks was linked to activation of a cell-death-inducing factor, called Bax.

"The link between VacA action at the mitochondria and Bax-dependent cell death had previously been unknown," Blanke said.

This study provides a first direct link between a bacterial toxin-mediated disruption of mitochondrial dynamics and host cell death, Blanke said. It also opens a new avenue of investigation of other diseases linked to impaired mitochondrial function, he said.

"Hundreds of human diseases and disorders are associated with mitochondrial dysfunction, ranging from cancers to degenerative diseases such as Alzheimer's disease and Parkinson's," Blanke said. "As yet, no one has methodically investigated a potential link between bacterial infections and mitochondrial diseases, despite the fact that several dozen pathogenic bacteria and viruses are known to directly target mitochondria."

Blanke and his colleagues are beginning to investigate that link.

"To us, finding that a pathogen can disrupt mitochondria in a manner that has striking similarities to what has been observed in known mitochondrial diseases is potentially very exciting," said Blanke, who also is an affiliate of the Institute for Genomic Biology at Illinois.


'/>"/>

Contact: Diana Yates
diya@illinois.edu
217-333-5802
University of Illinois at Urbana-Champaign
Source:Eurekalert  

Related medicine news :

1. 23andMe discovers genetic variant that may protect those at risk for Parkinsons disease
2. Louisiana State University Health Sciences Center research discovers key to survival of brain cells
3. UNH researcher discovers research manipulated to support pro-eugenic beliefs
4. Research discovers genetic link to Barretts esophagus, esophageal cancer
5. Expert discovers simple method of dealing with harmful radioactive iodine
6. UCSF team discovers key to fighting drug-resistant leukemia
7. UCSF team discovers new way to predict breast cancer survival and enhance effectiveness of treatment
8. OHSU Doernbecher discovers new approach to drug resistance in aggressive childhood cancer
9. MU chemist discovers shortcut for processing drugs
10. deCODE discovers genetic markers that improve the power of PSA testing for detecting prostate cancer
11. UT professor defines play, discovers even turtles need recess
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Team discovers how a cancer-causing bacterium spurs cell death
(Date:3/24/2017)... ... March 24, 2017 , ... “Finding Christ Through Social Media: ... journal chronicling the writer’s path toward true communion with God. “Finding Christ Through ... is the creation of published author Lea Michelle Johnson, a follower of Christ, ...
(Date:3/24/2017)... (PRWEB) , ... March 24, 2017 , ... ... collection of inspiring stories about real people of God in congregations across the ... John Miller, a Presbyterian minister ordained in 1964 who has served congregations in ...
(Date:3/23/2017)... ... 2017 , ... A recent report from the National Council on Teacher Quality ... report suggests, based on a review of GPA and SAT/ACT requirements at 221 institutions ... U.S. It argues that this higher bar should be set by states, by the ...
(Date:3/23/2017)... New Braunfels, TX (PRWEB) , ... March 23, 2017 , ... ... a new clinic, located at 960 Gruene Road in Building 2. The clinic is ... co-owner Dr. Andrew Bennett, PT, says opening the company’s second New Braunfels location brings ...
(Date:3/23/2017)... ... 23, 2017 , ... The MBI “Hall of Fame” recognizes the contributions of those whose careers ... impact on the careers of all others involved. , On Monday, March 21st, ... MBI’s Hall of Fame. The induction took place during the World of Modular – ...
Breaking Medicine News(10 mins):
(Date:3/24/2017)... , Mar. 24, 2017 Research and Markets has ... Analysis, 2016" report to their offering. ... The IPF pipeline is very strong with a total ... & Co., Inc., Biogen and Sanofi are involved in the development of ... which one is in Phase III stage, 15 are in Phase II ...
(Date:3/24/2017)... YORK , March 24, 2017 ... and Equipment stocks, which are: Neovasc Inc. (NASDAQ: NVCN), Hologic ... Heart Inc. (NASDAQ: SSH ). These companies are ... its prior gains on Thursday, March 23 rd , 2017, ... afternoon, while shares of health care companies in the S&P ...
(Date:3/24/2017)... surveys with 9,250 insured consumers fielded from February 2015 ... help from their plans in five key areas: 1) ... help closing gaps in care, 3) better digital connections, ... real-time guidance. Meeting these needs is essential to promoting ... A Reason to Stay Engaged in Health ...
Breaking Medicine Technology: