Navigation Links
Key function of mutation in hereditary breast and ovarian cancer gene discovered
Date:9/1/2011

Richmond, Va. (September 1, 2011) It is widely known that mutations in the breast cancer susceptibility 1 (BRCA1) gene significantly increase the chance of developing breast and ovarian cancers, but the mechanisms at play are not fully understood. Now, researchers at Virginia Commonwealth University Massey Cancer Center have shown that certain BRCA1 mutations result in excessive, uncontrolled DNA repair, which challenges the prior assumption that mutations in BRCA1 only contribute to breast cancer through a reduction in function.

Recently published in the journal Aging, the study led by Kristoffer Valerie, Ph.D., discovered that certain BRCA1 mutations affecting the BRCA1 C-terminal (BRCT) binding site resulted in excessive DNA repair, or hyper-recombination, which may contribute to the development of breast and ovarian cancers. The BRCT domain is a protein binding site typically found on DNA repair proteins like BRCA1 that are responsible for maintaining genomic stability and facilitating DNA repair. This study has implications for the treatment, diagnosis and development of therapies for patients with breast and ovarian cancer.

"Our findings suggest that caution should be exercised when targeting BRCA1 for breast and ovarian cancer therapies," says Valerie, co-leader of the Radiation Biology and Oncology program and a professor in the Department of Radiation Oncology at VCU Massey Cancer Center. "We need to better understand the biological mechanisms that lead to the development of breast and ovarian cancer before we attempt to attack it through targeted therapies aimed at causing DNA damage."

When DNA damage occurs, various forms of BASC (BRCA1-associated genome surveillance complex) bind to the BRCT domain on BRCA1. BASC is a protein complex that in part binds to the BRCT domain and serves as a "docking site" for other proteins and enzymes to come in, effectively repair the DNA damage and leave when repair is completed. However, certain BRCT mutants unable to bind to BASC disrupt the delicate DNA repair process. Previously, it was assumed this meant that BRCA1 was unable to assist with the repair process and, thus, recombination did not occur.

Valerie and his colleagues showed through experiments with cultured breast cancer cells and tissue samples from breast cancer patients that BRCT mutants increased ubiquination of BASC, which, in turn, increased recombination several-fold over normal levels. Ubiquitin is a small protein in all living organisms that "marks" other proteins for degradation or, as more recently discovered, the participation in specific cellular processes such as recombination. The researchers proposed that the hyper-recombination resulting from increased ubiquination of the BASC might result in improperly repaired DNA and increased genomic instability, which could lead to the development and aggressive progression of breast and ovarian cancers.

"Our results point to ubiquitination as a potential therapeutic target," says Valerie. "By disrupting ubiquitination we may be able to prevent hyper-recombination and stop the growth of cancer cells with these BRCT mutations. This might sensitize the cancer cells to radiation therapy while having little effect on cells with normal BRCA1 function."

The researchers hope to continue studying the role of BRCA1 in DNA double-strand break repair in order to determine whether the mutations they examined are important for the onset of cancer and whether targeted therapies can be developed.


'/>"/>

Contact: John Wallace
wallacej@vcu.edu
804-628-1550
Virginia Commonwealth University
Source:Eurekalert

Related medicine news :

1. Common Heart Dysfunction Can Help Bring on Heart Failure
2. When erectile dysfunction isnt whole story
3. New piece to the puzzle of brain function
4. Medical Tattoo Tracks Body Functions
5. With Age, Focus on Body Shifts From Appearance to Function
6. Neighborhood status influences older womens cognitive function, study finds
7. Antioxidants of growing interest to address infertility, erectile dysfunction
8. Drug improves brain function in condition that leads to Alzheimers
9. Exposure to Common Chemicals May Affect Thyroid Function
10. Stem cell treatment may restore cognitive function in patients with brain cancer
11. New brain research suggests eating disorders impact brain function
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/13/2017)... Vegas, Nevada (PRWEB) , ... October 13, 2017 , ... ... 7® Hemp CBD Oil utilizing Purzorb™ technology. Applying the Purzorb™process to full spectrum CBD ... dose required and providing a CBD form that can be easily incorporated into liquid ...
(Date:10/13/2017)... (PRWEB) , ... October 13, 2017 , ... The Visiting ... Day Market. Featuring a collection of specialty vendors and unique items from across the ... and quality-focused health and wellness services offered by the VNA. The boutique will ...
(Date:10/13/2017)... ... October 13, 2017 , ... Coveros, a ... has been awarded a contract by the Center for Medicare and Medicaid Services ... accelerate the enterprise use of Agile methodologies in a consistent and high value ...
(Date:10/12/2017)... ... ... Planet Fitness, one of the largest and fastest growing franchisors and operators ... location in Covington, LA at 401 N. U.S. Highway 190, in January of 2018. ... in the Holiday Square shopping center. Its location allows it to serve both Covington ...
(Date:10/12/2017)... ... 12, 2017 , ... Information about the technology: , Otomagnetics ... enable prevention of a major side effect of chemotherapy in children. Cisplatin and ... For cisplatin, hearing loss is FDA listed on-label as a dose limiting toxicity. ...
Breaking Medicine News(10 mins):
(Date:10/12/2017)... , Oct. 12, 2017 AVACEN Medical ... the company with their  2017 New Product Innovation Award ... on extensive primary and secondary medical device market research by ... through its first-to-market OTC, drug-free pain relief product, the AVACEN ... approach to treating fibromyalgia widespread pain. ...
(Date:10/12/2017)... -- West Pharmaceutical Services, Inc. (NYSE: WST), ... administration, today announced that it will release third-quarter 2017 ... 26, 2017, and will follow with a conference call ... a.m. Eastern Time. To participate on the call, please ... is 94093362. A ...
(Date:10/11/2017)...  Caris Life Sciences ® , a leading innovator ... precision medicine, today announced that St. Jude Medical Center,s ... (POA) as its 17 th member. Through participation ... Cancer Institute will help develop standards of care and ... making cancer treatment more precise and effective. ...
Breaking Medicine Technology: