Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Role of microRNA identified in breast cancer

15.08.2005


Scientists mining vast, largely unexplored regions of the human genome have identified a small handful of mini-molecules that play a major role in the development of cancer and perhaps many other diseases.



This newly identified set of molecules is called microRNA (miRNA), a collection of hundreds of snippets of non-coding RNA – typically no more than 22 nucleotides in length – that may comprise a master network controlling genes and protein production throughout the body, according to scientists in Ohio State University’s Comprehensive Cancer Center.

The researchers were the first to define how miRNA malfunctions in some forms of leukemia and lymphoma, and now have discovered how it works in breast cancer. More importantly, they say the miRNA “signature” in breast cancer is directly linked to several biological features that physicians routinely use to diagnose and appropriately treat the disease.


The findings appear in the Aug. 15 issue of Cancer Research.

“MiRNA is opening up a whole new way of understanding carcinogenesis,” says Carlo Croce, professor and chair of the department of molecular virology, immunology and medical genetics at Ohio State and the senior author of the study.

Traditional science holds that a specific stretch of DNA, or gene, encodes a sequence of messenger RNA that in turn creates instructions for the cell to make a particular protein. Cancer arises when there are mutations, deletions or other alterations in that initiating gene.

But what governs the entire process? A growing number of researchers like Croce believe that miRNA may play a major role. In contrast to regular RNA, miRNA does not code for protein production. Instead, it causes the destruction of coding RNA directly, or garbles its translational activity so proper protein production cannot take place.

MiRNA was first discovered almost 15 years ago in studies of roundworms, and since then, it has been found throughout plant and animal genomes. Because it becomes active early on in development and appears to be tissue-specific, researchers believe miRNA plays a fundamental role throughout an organism’s lifespan.

Scientists have identified over 200 distinct miRNAs, but Croce feels there may be hundreds more, and adds that researchers are just beginning to understand what they do. “Some of the breast cancer-specific miRNA we identified appear to act like tumor suppressors, and others appear to act like oncogenes, encouraging tumor growth.”

Interestingly, earlier research in Croce’s laboratory revealed that the majority of miRNA genes in humans are located near chromosomal sites that are especially vulnerable to alteration, a finding that leads him to believe that the role of miRNA in cancer is underestimated.

Croce, along with colleagues at Ohio State, Thomas Jefferson University and three cancer centers in Italy, used a microarray containing all known miRNA to examine miRNA activity in 76 breast tumors. They compared the findings to a microarray analysis of 34 samples of normal breast tissue.

They found 29 miRNAs that are significantly deregulated in breast cancer (some were over-expressed and others were under-expressed) and discovered that only five members of that group (identified as miR10b, miR-125b, miR-145, miR-21 and miR-155) were needed to successfully separate normal tissue from cancerous tissue 100 percent of the time.

They also conducted multiple tests designed to reveal any links between the newly identified expression pattern and important clinical features of the breast cancer, such as the type of the cancer - lobular versus ductal, estrogen and progesterone receptor status, lymph node metastasis, vascular invasion, proliferation index, and presence of two genes that can play a role in tumor growth, HER2 and p53.

They found that miRNA expression was correlated with breast tumors’ hormone status as well as its metastatic, invasive and proliferative potential.

“This leaves little doubt that aberrant expression of miRNA is involved in the development of breast cancer,” says Croce, adding that this information and the results of related studies already under way should offer valuable information for physicians as well as for researchers designing new treatments.

The National Cancer Institute and a Kimmel Scholar Award supported the study, as well as grants from the Associazione Italiana per la Ricerca and Cancro; Ministero dell’Istruzione, dell’Universita e della Ricera Programma Post-genoma; Ministero della Salute Italiano; and Progetto CAN2005-Comitato dei Sostenitori.

Michelle Gailiun | EurekAlert!
Further information:
http://www.osu.edu

More articles from Life Sciences:

nachricht Decoding the genome's cryptic language
27.02.2017 | University of California - San Diego

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

New pop-up strategy inspired by cuts, not folds

27.02.2017 | Materials Sciences

Sandia uses confined nanoparticles to improve hydrogen storage materials performance

27.02.2017 | Interdisciplinary Research

Decoding the genome's cryptic language

27.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>