Featured Research

from universities, journals, and other organizations

Male Sex Hormones Cooperate With Breast Cancer Gene To Suppress Tumors

Date:
July 1, 2003
Source:
Salk Institute
Summary:
BRCA-2, a gene linked with breast and ovarian cancer, cooperates with male sex hormones to enhance its ability to activate transcription of genes, which may suppress tumor formation in normal cells, Salk Institute researchers have found.

BRCA-2, a gene linked with breast and ovarian cancer, cooperates with male sex hormones to enhance its ability to activate transcription of genes, which may suppress tumor formation in normal cells, Salk Institute researchers have found.

The study, published in the June 10 Proceedings of the National Academy of Sciences, provides details on how the normal form of the gene may work, and how mutant forms of BRCA-2 may malfunction and therefore likely contribute to the development of breast cancer. It also gives greater insight into the causes of male breast cancer. BRCA-2 is one of two genes (the other is BRCA-1) linked to at least 10 percent of all breast cancers; the mutant form appears in nearly all male breast cancers.

Sook Shin, a postdoctoral fellow at the Salk, and Inder Verma, a Salk professor of genetics, found that the normal form of BRCA-2 enhanced the activity of androgen receptors that bind to androgens, which are male sex hormones like testosterone. Androgens exhibit antiproliferative activity in addition to their actions in developing male sex characteristics. Women also produce androgens, but have different levels in their bodies; the hormones play a role in female and male cancers.

In its mutated form, however, BRCA-2 could not enhance the androgen receptor's activity and thus may allow cancer cells to proliferate, the scientists discovered. Interestingly, for BRCA2 to function, it needs to synergize with co-activators located on the cell nucleus named GRIP1, a protein previously identified by Salk scientists working on nuclear hormone receptors in Salk Professor Ron Evans' laboratory.

"We think that BRCA-2 may be involved in DNA repair, or synthesis of new gene products, but haven't had enough detail on how this gene functions," said Verma. "This study shows how BRCA-2 helps androgen receptors do a better job of perhaps suppressing tumors, and may help us arrive at new targets for treating or preventing breast cancer."

By comparing mutated and normal forms of BRCA-2 in mouse cells, Sook Shin found that the normal BRCA-2 enhanced the androgen receptors' transcriptional activity (copying DNA into RNA, ultimately producing gene products) by binding with the receptor. The binding, however, could only happen with the help of GRIP1 and enhanced activity by 10-fold. Furthermore BRCA2 and GRIP1 cooperate with histone acetyl transferase enzymes required for remodeling chromatin, the material in chromosomes, providing more evidence of BRCA-2's role in DNA repair and possible tumor suppression. The mutant form of BRCA-2 could not enhance androgen receptor activity.

The scientists' work will take several years before there is any sign of a new treatment for cancer. But since people who have the mutated form of BRCA-1 or 2 face a much higher chance of getting cancer than normal, knowing how these genes work should eventually prove invaluable in reducing cases of cancer.

Verma's team now is looking at what other genes are turned on by this interaction of BRCA-2, GRIP1 and male sex hormones, and what are the specific targets in the cell of the breast cancer genes.

The Salk Institute for Biological Studies, located in La Jolla, Calif., is an independent nonprofit organization dedicated to fundamental discoveries in the life sciences, the improvement of human health and conditions, and the training of future generations of researchers. Jonas Salk, M.D., founded the institute in 1960 with a gift of land from the City of San Diego and the financial support of the March of Dimes Birth Defects Foundation.


Story Source:

The above story is based on materials provided by Salk Institute. Note: Materials may be edited for content and length.


Cite This Page:

Salk Institute. "Male Sex Hormones Cooperate With Breast Cancer Gene To Suppress Tumors." ScienceDaily. ScienceDaily, 1 July 2003. <www.sciencedaily.com/releases/2003/06/030630111151.htm>.
Salk Institute. (2003, July 1). Male Sex Hormones Cooperate With Breast Cancer Gene To Suppress Tumors. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2003/06/030630111151.htm
Salk Institute. "Male Sex Hormones Cooperate With Breast Cancer Gene To Suppress Tumors." ScienceDaily. www.sciencedaily.com/releases/2003/06/030630111151.htm (accessed July 23, 2014).

Share This




More Health & Medicine News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Stone Fruit Listeria Scare Causes Sweeping Recall

Stone Fruit Listeria Scare Causes Sweeping Recall

Newsy (July 22, 2014) The Wawona Packing Company has issued a voluntary recall on the stone fruit it distributes due to a possible Listeria outbreak. Video provided by Newsy
Powered by NewsLook.com
Huge Schizophrenia Study Finds Dozens Of New Genetic Causes

Huge Schizophrenia Study Finds Dozens Of New Genetic Causes

Newsy (July 22, 2014) The 83 new genetic markers could open dozens of new avenues for schizophrenia treatment research. Video provided by Newsy
Powered by NewsLook.com
CDC Head Concerned About a Post-Antibiotic Era

CDC Head Concerned About a Post-Antibiotic Era

AP (July 22, 2014) Sounding alarms about the growing threat of antibiotic resistance, CDC Director Tom Frieden warned Tuesday if the global community does not confront the problem soon, the world will be living in a devastating post-antibiotic era. (July 22) Video provided by AP
Powered by NewsLook.com
Courts Conflicted Over Healthcare Law

Courts Conflicted Over Healthcare Law

AP (July 22, 2014) Two federal appeals courts issued conflicting rulings Tuesday on the legality of the federally-run healthcare exchange that operates in 36 states. (July 22) 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:
from the past week

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