Featured Research

from universities, journals, and other organizations

Protein Thought To Promote Cancer Instead Functions As Tumor Suppressor

Date:
July 8, 2008
Source:
UT Southwestern Medical Center
Summary:
A protein previously thought to promote colorectal cancer instead suppresses the growth of human cancer cells in culture, researchers have found.

A research team led by Dr. Lawrence Lum (right) and including Dr. Wei Tang has discovered that a protein previously thought to promote colorectal cancer instead suppresses the growth of human cancer cells in culture.
Credit: UT Southwestern Medical Center

A protein previously thought to promote colorectal cancer instead suppresses the growth of human cancer cells in culture, researchers at UT Southwestern Medical Center have found.

Related Articles


"This finding reshapes a fundamental model of how colorectal cancer arises," said Dr. Lawrence Lum, assistant professor of cell biology at UT Southwestern and senior author of the study, which appears online today and in a future issue of the Proceedings of the National Academy of Sciences.

Approximately 90 percent of colorectal cancers are caused by a biochemical malfunction that arises from mutations in a gene that activates a gene called TCF7L2, Dr. Lum said. As a result, TCF7L2 has been suspected of helping to trigger colorectal cancer.

In the current study, the researchers used a novel genetic screening approach known as RNAi mediated interference, or RNAi, to identify genes that contributed to this malfunction.

The researchers employed more than 80,000 small snippets of chemically synthesized RNAs (ribonucleic acids) known as "small interfering RNAs" or siRNAs, that are each capable of inactivating a specific gene. The researchers mixed these siRNAs with specially engineered human cancer cells that glowed when the cancer-causing malfunction is activated. When an siRNA made a cell glow, the researchers were able to flag the gene as a candidate cancer gene.

As the researchers examined the genes of interest more closely, they unexpectedly found that a gene called TCF7L2, which had been thought to boost malignant cell growth, instead suppressed it. When the gene was inactivated, human colorectal cancer cells grew more rapidly in culture and emitted a stronger glow.

"The function of TCF7L2 in cancer was previously determined from studies in animals but no one has genetically tested its role in human colorectal cancer cells before," said Dr. Lum, who is a Virginia Murchison Linthicum Scholar in Medical Research. "Prior to the advent of RNAi technology, this was very difficult to do in human cultured cells."

The next step is to understand more fully all the steps in the biochemical pathway involved in controlling the action of TCF7L2. This knowledge could then be used to identify new therapeutic targets for treating colorectal cancer. Therapeutic strategies derived from such studies may also be useful in treating type II diabetes, for which risk is strongly associated with mutations in TCF7L2, Dr. Lum said.

Dr. Lum noted that the findings about TCF7L2 show the effectiveness of this high throughput screening technique, which can quickly and systematically check many thousands of genes.

The success of this relatively new screening method for identifying candidate cancer genes demonstrates its usefulness to understanding human disease, Dr. Lum said.

"It's a way to analyze human gene action directly in human tissue at a genome-scale," he said.

Other UT Southwestern researchers involved in the study were Dr. Wei Tang, postdoctoral researcher in cell biology; graduate student Michael Dodge; former laboratory technician Deepika Gundapaneni; Dr. Carolyn Michnoff, former manager of the High-Throughput Screening facility; and Dr. Michael Roth, professor of biochemistry.

The work was supported by the National Institutes of Health, the American Cancer Society, and the Welch Foundation.


Story Source:

The above story is based on materials provided by UT Southwestern Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

UT Southwestern Medical Center. "Protein Thought To Promote Cancer Instead Functions As Tumor Suppressor." ScienceDaily. ScienceDaily, 8 July 2008. <www.sciencedaily.com/releases/2008/07/080707171734.htm>.
UT Southwestern Medical Center. (2008, July 8). Protein Thought To Promote Cancer Instead Functions As Tumor Suppressor. ScienceDaily. Retrieved March 31, 2015 from www.sciencedaily.com/releases/2008/07/080707171734.htm
UT Southwestern Medical Center. "Protein Thought To Promote Cancer Instead Functions As Tumor Suppressor." ScienceDaily. www.sciencedaily.com/releases/2008/07/080707171734.htm (accessed March 31, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Tuesday, March 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Solitair Device Aims to Takes Guesswork out of Sun Safety

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015) — The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Soda, Salt and Sugar: The Next Generation of Taxes

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015) — Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline. Video provided by Washington Post
Powered by NewsLook.com
UnitedHealth Buys Catamaran

UnitedHealth Buys Catamaran

Reuters - Business Video Online (Mar. 30, 2015) — The $12.8 billion merger will combine the U.S.&apos; third and fourth largest pharmacy benefit managers. Analysts say smaller PBMs could also merge. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
S. Leone in New Anti-Ebola Lockdown

S. Leone in New Anti-Ebola Lockdown

AFP (Mar. 28, 2015) — Sierra Leone imposed a three-day nationwide lockdown Friday for the second time in six months in a bid to prevent a resurgence of the deadly Ebola virus. Duration: 01:17 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins