Featured Research

from universities, journals, and other organizations

Dual Role In Breast Tissue For Protein Involved In Leukemia

Date:
June 30, 2009
Source:
Georgetown University Medical Center
Summary:
A protein known to play a role in growth of some types of leukemia appears to have a mixed function in breast cancer development, say researchers.

A protein known to play a role in growth of some types of leukemia appears to have a mixed function in breast cancer development, say researchers from the Lombardi Comprehensive Cancer Center at Georgetown University Medical Center (GUMC).

The findings, presented at the annual meeting of the Endocrine Society in Washington, DC, indicate that the function of this protein, known as Stat5a, may be different in developing breast cancer cells that are estrogen receptor-positive as compared to estrogen receptor-negative. When estrogen receptor levels were overexpressed, loss of Stat5a reduced development of a lobular type of preneoplasia. However, when estrogen receptor levels were normal, loss of Stat5a not only had no effect on reducing preneoplasia, but increased susceptibility to carcinogen-induced breast cancer. The results illustrate the importance of breast cancer heterogeneity when testing new therapeutic targets.

The researchers say Stat5a could be a target for treatment of leukemia, but add, "If Stat5a is to be used as a drug target for leukemia or other cancers, it is important to fully understand how altering its function impacts the breast, especially since it appears it may play different roles in different types of breast cancer," says the study's lead author, Anne Miermont, MS, a doctoral graduate student in tumor biology at Georgetown University Medical Center.

Stat5a is a member of the STAT family of proteins, which are key to regulating cell growth and differentiation. Because they have been found to be over-expressed in leukemia, Miermont and Priscilla Furth, MD, a professor of oncology, sought to see if they were important in breast cancer development. Estrogen receptors are over-expressed in more than half of human breast cancers, so the investigators set up studies to test if the function of Stat5a was the same or different in cells with estrogen receptor overexpression.

They found that Stat5a A is rather "two-faced" when it comes to its role in breast tissue. Previous studies had shown that mice born without the gene produce breast cells that are a little less differentiated than they should be, meaning that they are not fully developed enough to participate in milk production. Miermont found that when the animals were exposed to a cancer-causing chemical, they were more likely to develop breast cancer than mice with intact Stat5a genes. At the same time, however, Miermont found that when estrogen receptor was over-expressed, Stat5a collaborated with it to promote growth of a type of precancerous lesion of the breast termed a hyperplastic alveolar nodule.

"Our studies in in vivo mouse models illustrate a dual role for the Stat5a protein in breast tissue. While it can contribute to the growth of one type of precancerous lesion in the breast, this protein also appears to protects mammary cells from carcinogenic exposure," says Miermont.

These findings need to be validated and expanded, Furth says, but she adds that "while Stat5a is obviously a complicated protein that has many functions, the results underscore the need to specifically understand the mechanisms that regulate its different roles in breast cells and how changes in Stat5a activity may affect different types of breast cancer generation."

The National Cancer Institute, National Institutes of Health and the Department of Defense Breast Cancer Research Program funded the study.


Story Source:

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


Cite This Page:

Georgetown University Medical Center. "Dual Role In Breast Tissue For Protein Involved In Leukemia." ScienceDaily. ScienceDaily, 30 June 2009. <www.sciencedaily.com/releases/2009/06/090612143936.htm>.
Georgetown University Medical Center. (2009, June 30). Dual Role In Breast Tissue For Protein Involved In Leukemia. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2009/06/090612143936.htm
Georgetown University Medical Center. "Dual Role In Breast Tissue For Protein Involved In Leukemia." ScienceDaily. www.sciencedaily.com/releases/2009/06/090612143936.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) 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