Featured Research

from universities, journals, and other organizations

Researchers Identify Gene As Protector Of DNA, Enemy Of Tumors

Date:
August 3, 2006
Source:
University of Texas M. D. Anderson Cancer Center
Summary:
A single gene plays a pivotal role launching two DNA damage detection and repair pathways in the human genome, suggesting that it functions as a previously unidentified tumor suppressor gene, researchers at the University of Texas M. D. Anderson Cancer Center report in Cancer Cell.

A single gene plays a pivotal role launching two DNA damage detection and repair pathways in the human genome, suggesting that it functions as a previously unidentified tumor suppressor gene, researchers at The University of Texas M. D. Anderson Cancer Center report in Cancer Cell.

Related Articles


The advance online publication also reports that the gene - called BRIT1 - is under-expressed in human ovarian, breast and prostate cancer cell lines.

Defects in BRIT1 seem to be a key pathological alteration in cancer initiation and progression, the authors note, and further understanding of its function may contribute to novel, therapeutic approaches to cancer.

"Disruption of BRIT1 function abolishes DNA damage responses and leads to genomic instability," said senior author Shiaw-Yih Lin, Ph.D., assistant professor in the Department of Molecular Therapeutics at M. D. Anderson. Genomic instability fuels the initiation, growth and spread of cancer.

A signaling network of molecular checkpoint pathways protects the human genome by detecting DNA damage, initiating repair and halting division of the damaged cell so that it does not replicate.

In a series of laboratory experiments, Lin and colleagues show that BRIT1 activates two of these checkpoint pathways. The ATM pathway springs into action in response to damage caused by ionizing radiation. The ATR pathway responds to DNA damage caused by ultraviolet radiation.

By using small interfering RNA (siRNA) to silence the BRIT1 gene, the scientists shut down both checkpoint pathways in cells exposed to either type of radiation.

Researchers then used siRNA to silence the gene in normal human mammary epithelial cells (HMEC). The result: Inactivation of the gene caused chromosomal aberrations in 21.2 to 25.6 percent of cells. Control group HMEC had no cells with chromosomal aberrations. In cells with the gene silenced that were then exposed to ionizing radiation, 80 percent of cells had chromosomal aberrations.

"We also found that BRIT1 expression is aberrant in several forms of human cancer," Lin said. The team found reduced expression of the gene in 35 of 87 cases of advanced epithelial ovarian cancer. They also found reduced expression in breast and prostate cancer tissue compared with non-cancerous cells.

Genetic analysis of breast cancer specimens revealed a truncated, dysfunctional version of the BRIT1 protein in one sample.

Loss of the DNA damage checkpoint function and the ability to proliferate indefinitely are two cellular changes required for the development of cancer. Lin and colleagues have now tied the gene to both factors. They previously identified BRIT1 as a repressor of hTERT, a protein that when reactivated immortalizes cells, allowing them to multiply indefinitely.

Co-authors with Lin are first author Rekha Rai, Ph.D., Hui Dai, M.D., John P. Lahad, M.S., Jiyong Liang, Ph.D., and Gordon Mills, M.D., Ph.D., all of the Department of Molecular Therapeutics; Asha S. Multani, Ph.D., Department of Cancer Genetics at M.D. Anderson; Funda Meric-Bernstam, M.D., Department of Surgical Oncology, M. D. Anderson; Kaiyi Li, Ph.D., Department of Surgery at Baylor College of Medicine; and Koei Chin, M.D., Ph.D., and Joe Gray, Ph.D., of the Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, Calif.


Story Source:

The above story is based on materials provided by University of Texas M. D. Anderson Cancer Center. Note: Materials may be edited for content and length.


Cite This Page:

University of Texas M. D. Anderson Cancer Center. "Researchers Identify Gene As Protector Of DNA, Enemy Of Tumors." ScienceDaily. ScienceDaily, 3 August 2006. <www.sciencedaily.com/releases/2006/08/060803181449.htm>.
University of Texas M. D. Anderson Cancer Center. (2006, August 3). Researchers Identify Gene As Protector Of DNA, Enemy Of Tumors. ScienceDaily. Retrieved April 25, 2015 from www.sciencedaily.com/releases/2006/08/060803181449.htm
University of Texas M. D. Anderson Cancer Center. "Researchers Identify Gene As Protector Of DNA, Enemy Of Tumors." ScienceDaily. www.sciencedaily.com/releases/2006/08/060803181449.htm (accessed April 25, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, April 25, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

85 Killed in Niger by Meningitis Since Start of Year

85 Killed in Niger by Meningitis Since Start of Year

AFP (Apr. 24, 2015) A meningitis outbreak in Niger has killed 85 people since the start of the year prompting authorities to close schools in the capital Niamey until Monday. Video provided by AFP
Powered by NewsLook.com
C-Section Births a Trend in Brazil

C-Section Births a Trend in Brazil

AFP (Apr. 24, 2015) More than half of Brazil&apos;s babies are born via cesarean section, as mothers and doctors opt for a faster and less painful experience despite the health risks. Duration: 02:02 Video provided by AFP
Powered by NewsLook.com
Anti-Malaria Jab Hope

Anti-Malaria Jab Hope

Reuters - News Video Online (Apr. 24, 2015) The world&apos;s first anti-malaria vaccine could get the go-ahead for use in Africa from October if approved by international regulators. Paul Chapman reports. Video provided by Reuters
Powered by NewsLook.com
3D Food Printing: The Meal of the Future?

3D Food Printing: The Meal of the Future?

AP (Apr. 23, 2015) Developers of 3D food printing hope the culinary technology will revolutionize the way we cook and eat. (April 23) Video provided by AP
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