Experts from the Lombardi Comprehensive Cancer Center at Georgetown University Medical Center (GUMC) say that this finding indicates that the function of the protein, known as Stat5a, may be different in developing breast cancer cells that are estrogen receptor-positive as compared to estrogen receptor-negative.
Presenting their findings at the annual meeting of the Endocrine Society in Washington, DC, the researchers revealed that when estrogen receptor levels were over-expressed, 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 also increased susceptibility to carcinogen-induced breast cancer.
According to the researchers, the new findings illustrate the importance of breast cancer heterogeneity when testing new therapeutic targets.
The researchers agree that Stat5a could be a target for treatment of leukemia.
However, lead author Dr. Anne Miermont, a doctoral graduate student in tumor biology at Georgetown University Medical Center, adds: “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.”
Stat5a belongs to a family of proteins that are key to regulating cell growth and differentiation. Because they have been found to be over-expressed in leukemia, the researchers sought to see whether they were important in breast cancer development or not.
Miermont and Dr. Priscilla Furth, a professor of oncology, say that estrogen receptors are over-expressed in more than half of human breast cancers, and thus they set up studies to test whether the function of Stat5a was the same or different in cells with estrogen receptor over-expression or not.
Their study showed that Stat5a A is rather “two-faced” when it comes to its role in breast tissue.
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.
However, when estrogen receptor was over-expressed, Stat5a collaborated with it to promote growth of a type of pre-cancerous 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.
Furth says that these findings need to be validated and expanded, 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. (ANI)
Filed under Cancer, News
Related?Rogue protein behind breast cancer foundJanuary 14th, 2009 TORONTO - A new Canadian study has found a protein that is linked to the progression of breast cancer. Researchers at the University of Montreal and the University of Alberta say the new protein - named ARF1 - is crucially active in promoting growth of cancer cells and thus tumours. New findings may take scientists a step ahead to treat deadly Mixed-lineage LeukemiaDecember 19th, 2008 Blood cancer myeloid/lymphoid or mixed lineage leukemia (MLL) is very difficult to pre-detect, as a result survival rate of infants suffering with MLL is too low. Chromosomal translocations involving the mixed lineage leukemia (MLL) gene are often observed in acute leukemias of both myeloid and lymphocytic origin. Gene behind most common form of breast cancer identifiedMay 12th, 2009 WASHINGTON - Defects in a gene, called p18, have been found to be the cause of the most common form of breast cancer, say scientists. Researchers at the University of North Carolina at Chapel Hill School of Medicine and UNC Lineberger Comprehensive Cancer Center, say that their discovery, if combined with new laboratory techniques, could help scientists identify and test new treatments for luminal-type tumours,
Luminal-type tumours account for between 70 and 80 percent of all breast cancers, but are generally slower growing than other types. Gene that protects tumour suppressor in breast cancer identifiedApril 7th, 2009 WASHINGTON - In a novel study, researchers from The University of Texas M. D. Anderson Cancer Centre have identified a gene that protects PTEN, a major tumour-suppressor in breast cancer. Majority of breast cancer patients take antioxidants despite likely riskJune 8th, 2009 WASHINGTON - A large number of women with breast cancer go for antioxidant supplements while undergoing cancer treatment, despite the possible side-effects of the practice remain unknown, according to a study. The study called for additional research to determine the effects of antioxidant supplementation on the health and survival of breast cancer patients. 'Silencing' single gene in lung cancer disrupts genome functioningDecember 30th, 2008 WASHINGTON - 'Silencing' a single gene in lung cancer disrupts functioning of genome in cancer cases, according to a new study. Researchers also found a strong link between modification of the key gene, MTHFR, and tobacco use by lung cancer patients - even if the patient had smoked for a short period of time. Researchers unravel protein role in repair of cancer damaged cellJanuary 6th, 2009 WASHINGTON - A key protein in cells plays a critical role in not one but dual processes affecting the development of cancer, according to a new discovery. 'Most proteins involved in responding to DNA damage that can cause cancer either help detect the damage and warn the rest of the cell, or help repair the damage,' said David O. Potential new drug target to stop Alzheimer's progression identifiedMarch 20th, 2009 WASHINGTON - Scientists have moved a step closer to developing a drug that could actually stop the progress of Alzheimer's disease. They have identified a molecule that can form the basis for a new therapy for the neurodegenerative disease.
Protein involved in leukemia plays mixed role in breast cancer development
View this post on my blog: http://diseasecancer.net/protein-involved-in-leukemia-plays-mixed-role-in-breast-cancer-development
0 comments:
Post a Comment