Corporate Banner
Satellite Banner
Proteomics
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Protein Complex May Play Role in Preventing Many Forms of Cancer, Study Shows

Published: Tuesday, May 07, 2013
Last Updated: Tuesday, May 07, 2013
Bookmark and Share
Researchers at the Stanford University School of Medicine have identified a group of proteins that are mutated in about one-fifth of all human cancers.

The finding suggests that the proteins, which are members of a protein complex that affects how DNA is packaged in cells, work to suppress the development of tumors in many types of tissues.

The broad reach of the effect of mutations in the complex, called BAF, rivals that of another well-known tumor suppressor called p53. It also furthers a growing notion that these so-called chromatin-regulatory complexes may function as much more than mere cellular housekeepers.

"Although we knew that this complex was likely to play a role in preventing cancer, we didn't realize how extensive it would be," said postdoctoral scholar Cigall Kadoch, PhD. "It's often been thought that these complexes play supportive, maintenance-like roles in the cell. But this is really changing now."

Kadoch shares lead authorship of the study with postdoctoral scholar Diana Hargreaves, PhD. Gerald Crabtree, MD, professor of developmental biology and of pathology, is the senior author of the study, published online May 5 in Nature Genetics.

Chromatin-regulatory complexes work to keep DNA tightly condensed, while also granting temporary access to certain portions for replication or to allow the expression of genes necessary for the growth or function of the cell.

Members of Crabtree's laboratory have been interested in BAF complexes and their function for many years. Recently, they reported in the journal Nature that switching subunits within these complexes can convert human fibroblasts to neurons, which points to their instructive role in development and, possibly, cancer.

"Somehow these chromatin-regulatory complexes manage to compress nearly two yards of DNA into a nucleus about one one-thousandth the size of a pinhead," said Crabtree, who is also a member of the Stanford Cancer Institute and a Howard Hughes Medical Institute investigator. "And they do this without compromising the ability of the DNA to be replicated and selectively expressed in different tissues — all without tangling. In 1994 we reported that complexes of this type were likely to be tumor suppressors. Here we show that they are mutated in nearly 20 percent of all human malignancies thus far examined."

The researchers combined biochemical experiments with the data mining of 44 pre-existing studies to come to their conclusions, which would not have been possible without the advent of highly accurate, genome-wide DNA sequencing of individual human tumor samples. Interestingly, mutations to certain subunits, or particular combinations of mutations in the complex's many subunits, seem to herald the development of specific types of cancer — favoring the development of ovarian versus colon cancer, for example.

The importance of the BAF complex as a tumor suppressor is further emphasized by the fact that, in some cases, a mutation in one subunit is sufficient to initiate cancer development.

"For example," said Kadoch, "a type of mutation called a chromosomal translocation in the gene encoding one of these newly identified subunits, SS18, is known to be the hallmark of a cancer called synovial sarcoma. It is clearly the driving oncogenic event and very often the sole genomic abnormality in these cancers." Kadoch and Crabtree published a study in March in Cell uncovering the mechanism and functional consequences of BAF complex perturbation in synovial sarcoma.

The startling prevalence of mutations in the BAF complex was discovered when Kadoch conducted a series of experiments to determine exactly which proteins in the cell were true subunits of the complex. (The exact protein composition of the large complex varies among cell types and species.) Kadoch used an antibody that recognized one core component to purify intact BAF complexes in various cell types, including embryonic stem cells and skin, nerve and other cells. She then analyzed the various proteins isolated by the technique.

Using this method, Kadoch identified seven proteins previously unknown to be BAF components. She and Hargreaves then turned to previously published studies in which the DNA from a variety of human tumors had been sequenced to determine how frequently any of the members of the complex were mutated.

The results, once the newly discovered members were included, were surprising: 19.6 percent of all human tumors displayed a mutation in at least one of the complex's subunits. In addition, for some types of cancers (such as synovial sarcoma), every individual tumor sample examined had a mutation in a BAF subunit. The results suggest that the BAF complex, when unmutated, plays an important protective role against the development of cancer in many different tissues.

The researchers are now focused on learning how the mutations affect the tumor-suppressing activity of the BAF complex.

"We certainly want to further our understanding of the mechanism behind these findings," said Hargreaves. "Do they promote cancer development by inhibiting the proper progression of the cell cycle? Or perhaps they affect how the complex is positioned on the DNA. We'd like to determine how to recapitulate some of these mutations experimentally to see what types of defects they introduce into the complex."


Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,400+ scientific posters on ePosters
  • More than 3,700+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Long-sought Discovery Fills in Missing Details of Cell 'Switchboard'
A biomedical breakthrough reveals never-before-seen details of the human body’s cellular switchboard that regulates sensory and hormonal responses.
Monday, July 27, 2015
A Protein's Novel Role In Several Types Of Cancers Discovered
Stanford ChEM-H scientists are helping to develop a novel cancer therapy based on a new finding of a protein that inadvertently promotes cancer growth.
Friday, February 27, 2015
Stanford Chemists Take Step Toward Solving Mystery of How Enzymes Work
Steven Boxer and his students have found that the electrostatic field within an enzyme accounts for the lion's share of its success.
Wednesday, December 24, 2014
Scientists Identify Two Molecules that Affect Brain Plasticity in Mice
Stanford researchers have identified a set of molecular brakes that stabilize the developing brain’s circuitry.
Tuesday, December 01, 2009
Sequential Genomic Analysis Links Gene with Human Kidney Aging
The new approach that combines sequential transcriptional profiling and eQTL mapping, can help find other genetic associations.
Tuesday, October 27, 2009
Stanford Researchers Find Protein Targets for Potential Treatment of Multiple Sclerosis
Stanford researchers have identified therapy targets that could lead to personalized treatments for MS patients at each phase of the illness.
Monday, February 18, 2008
Scientific News
TOPLESS Plants Provide Clues to Human Molecular Interactions
Scientists at Van Andel Research Institute have revealed an important molecular mechanism in plants that has significant similarities to certain signaling mechanisms in humans, which are closely linked to early embryonic development and to diseases such as cancer.
Toxin from Salmonid Fish has Potential to Treat Cancer
Researchers from the University of Freiburg decode molecular mechanism of fish pathogen.
Study Finds Non-Genetic Cancer Mechanism
Cancer can be caused solely by protein imbalances within cells, a study of ovarian cancer has found.
Long-sought Discovery Fills in Missing Details of Cell 'Switchboard'
A biomedical breakthrough reveals never-before-seen details of the human body’s cellular switchboard that regulates sensory and hormonal responses.
Rice Disease-Resistance Discovery Closes the Loop for Scientific Integrity
Researchers reveal how disease resistant rice detects and responds to bacterial infections.
The Mystery of the Instant Noodle Chromosomes
Researchers from the Lomonosov Moscow State University evaluated the benefits of placing the DNA on the principle of spaghetti.
New Mussel-Inspired Surgical Protein Glue
Korean scientists have developed a light-activated, mussel protein-based bioadhesive that works on the same principles as mussels attaching to underwater surfaces and insects maintaining structural balance and flexibility.
Vital Protein in Healthy Fertilization Process Identified
Researchers at the National Institutes of Health have discovered a protein that plays a vital role in healthy egg-sperm union in mice.
Teeth Reveal Lifetime Exposures to Metals, Toxins
Researchers have identified dental biomarkers to reveal links between early iron exposure and late life brain diseases.
View of Bacterial Pump at the Atomic Level
Researchers have determined the structure of a simple but previously unexamined pump that controls the passage of proteins through a bacterial cell membrane, an achievement that offers new insight into the mechanics that allow bacteria to manipulate their environments.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,400+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,700+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!