miR-205 can be responsible for breast cancer

December 21, 2012

Over the past couple of years research into miRNAs has become increasingly diversified and attracted a great number of research articles across genetics and medicine. This should hardly come as a surprise to any scientist in the field, especially since it has become clear that miRNAs, a recently discovered class of non-coding RNAS, are represented in nearly all cellular functions and molecular pathways. A growing list of reports demonstrates that microRNAs play a critical role in cancer initiation and progression, and that miRNA alterations are ubiquitous in human cancers. In fact, several studies have shown that miRNAs can act either as tumor suppressors or as oncogenes, and that measurement of miRNA expression in malignancies may have diagnostic implications or otherwise lead to novel treatments of breast cancer.

In the article "Mir-205 modulates acinar size and morphology of transformed breast epithelial cells" which will be released later this week in OncomiRs - an open access journal published by Versita, molecular biologists from CEA Saclay and Université Paris-Sud, led by Prof. Annick Harel-Bellan, studied the microRNAs expression potentially responsible for the abnormal acini formation of breast cancer cells. They observed that the overexpression of the miR-205 influences the morphology of acini, linking this miRNA to breast epithelial cell transformation.

A genome-wide microRNA expression screen comparing non-transformed and tumorigenic MCF10A cell lines identified miR-205 as a potential modifier of acinus size. Forced expression of miR-205 in non-transformed MCF10A cells increased the size of acini, whereas miR-205 antisense oligonucleotides restored a normal morphology. MiR-205 did not modify cell proliferation, but rather inhibited cell death by apoptosis. Moreover, miR-205 targets ZEB1, an inhibitor of E-cadherin. Downregulating E-cadherin restored normal acinar morphology in miR-205 expressing cells, consistent with E-cadherin being involved in the miR-205-dependent acini phenotype.

The researchers further examined critical cellular formation in breast cancer. It has been demonstrated that normal breast epithelial cells form highly organized multi-cellular structures - the breast lobules, terminating in acinar structures called alveoli, which can be mimicked in vitro in three-dimensional (3D) cultures. Moreover, breast epithelial cells self-organize to form "acini". The size and morphology of acini is highly dependent on the degree of cancerous transformation of breast epithelial cells. Transformed cell lines form larger acini than normal cells, and cancer cells do not form normal acini, but instead form much larger aggregates of cells with no well-defined lumen.

Commenting on the research results, Prof. Annick Harel-Bellan notes: ' miR-205 is definitely not a simple tumor-suppressor miRNA in breast as previously believed, but it can be overexpressed in transformed cells and can be responsible for the abnormally large morphology of acini.'

The research highlights the complexity of miR-205 function in breast epithelial cells: miR-205 can act not only as a tumor suppressor, as formerly proposed, but also as an oncogene that favors cell proliferation or represses cell death. "Consequently, the use of miR-205 as a curative miRNA in cancer, as previously suggested by others, should be approached with great caution" observes Harel-Bellan in her article. Without doubt, continuous efforts to identify and describe miRNAs will provide novel insights into breast cancer biology, and will eventually arrange for a new molecular target for alternative treatments.
-end-


De Gruyter Open

Related Breast Cancer Articles from Brightsurf:

Oncotarget: IGF2 expression in breast cancer tumors and in breast cancer cells
The Oncotarget authors propose that methylation of DVDMR represents a novel epigenetic biomarker that determines the levels of IGF2 protein expression in breast cancer.

Breast cancer: AI predicts which pre-malignant breast lesions will progress to advanced cancer
New research at Case Western Reserve University in Cleveland, Ohio, could help better determine which patients diagnosed with the pre-malignant breast cancer commonly as stage 0 are likely to progress to invasive breast cancer and therefore might benefit from additional therapy over and above surgery alone.

Partial breast irradiation effective treatment option for low-risk breast cancer
Partial breast irradiation produces similar long-term survival rates and risk for recurrence compared with whole breast irradiation for many women with low-risk, early stage breast cancer, according to new clinical data from a national clinical trial involving researchers from The Ohio State University Comprehensive Cancer Center - Arthur G.

Breast screening linked to 60 per cent lower risk of breast cancer death in first 10 years
Women who take part in breast screening have a significantly greater benefit from treatments than those who are not screened, according to a study of more than 50,000 women.

More clues revealed in link between normal breast changes and invasive breast cancer
A research team, led by investigators from Georgetown Lombardi Comprehensive Cancer Center, details how a natural and dramatic process -- changes in mammary glands to accommodate breastfeeding -- uses a molecular process believed to contribute to survival of pre-malignant breast cells.

Breast tissue tumor suppressor PTEN: A potential Achilles heel for breast cancer cells
A highly collaborative team of researchers at the Medical University of South Carolina and Ohio State University report in Nature Communications that they have identified a novel pathway for connective tissue PTEN in breast cancer cell response to radiotherapy.

Computers equal radiologists in assessing breast density and associated breast cancer risk
Automated breast-density evaluation was just as accurate in predicting women's risk of breast cancer, found and not found by mammography, as subjective evaluation done by radiologists, in a study led by researchers at UC San Francisco and Mayo Clinic.

Blood test can effectively rule out breast cancer, regardless of breast density
A new study published in PLOS ONE demonstrates that Videssa® Breast, a multi-protein biomarker blood test for breast cancer, is unaffected by breast density and can reliably rule out breast cancer in women with both dense and non-dense breast tissue.

Study shows influence of surgeons on likelihood of removal of healthy breast after breast cancer dia
Attending surgeons can have a strong influence on whether a patient undergoes contralateral prophylactic mastectomy after a diagnosis of breast cancer, according to a study published by JAMA Surgery.

Young breast cancer patients undergoing breast conserving surgery see improved prognosis
A new analysis indicates that breast cancer prognoses have improved over time in young women treated with breast conserving surgery.

Read More: Breast Cancer News and Breast Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.