Featured Research

from universities, journals, and other organizations

No brakes on breast cancer cells

Date:
January 6, 2012
Source:
Helmholtz Association of German Research Centres
Summary:
Scientists have discovered a tiny RNA molecule, called miR-520, which at once blocks two important pathways in the development of cancer in cells. In estrogen receptor-negative breast cancer, the production of this microRNA is often reduced and this is correlated with malignant behavior of tumor cells. The team has found out that tumors with low levels of miR-520 have a particularly strong tendency to metastasize.

Breast cancer cells; proteins of the cytoskeleton are shown in red.
Credit: Lutz Langbein, German Cancer Research Center

Scientists of the German Cancer Research Center (DKFZ) have discovered a tiny RNA molecule, called miR-520, which at once blocks two important pathways in the development of cancer in cells. In estrogen receptor-negative breast cancer, the production of this microRNA is often reduced and this is correlated with malignant behavior of tumor cells. The DKFZ team has found out that tumors with low levels of miR-520 have a particularly strong tendency to metastasize.

MicroRNAs or miRNAs are tiny RNA molecules that have only about 20 nucleotides and do not code for proteins. They regulate many important processes in cells by binding to target messenger RNAs -- the instructions for protein production -, thus blocking production of the respective protein. In cancer, the production of some miRNAs is often reduced or amplified. This particularly affects miRNAs that regulate the activity of cancer-promoting genes.

A key molecule in the development of cancer is a transcription factor called NFkappaB, which is an important switch for many genes with inflammation-promoting effects. At DKFZ, Professor Dr. Stefan Wiemann and collaborators have now investigated whether microRNAs that affect NFkappaB production are deregulated in breast cancer. Jointly with colleagues at Heidelberg and Tuebingen University Hospitals, the DKFZ team studied over 800 miRNAs and discovered a family of RNA molecules known as miR-520, which particularly strongly reduce the production of NFkappaB. "If the cells produce less NFkappaB, the production of inflammation-promoting signaling molecules is reduced. This puts a brake on cancer growth, because these signaling molecules promote invasive capacity, formation of new vessels and metastasis," says Ioanna Keklikoglou, a doctoral student Wiemann's department, explaining this mechanism.

However, miR-520 does not only act like a cancer brake by suppressing NFkappaB. In addition, Wiemann's team discovered that this microRNA also blocks another cancer-promoting signaling pathway that is triggered by growth factor TGF-beta. TGF-beta signals cause malignant cells to be less firmly anchored in the tissue and, thus, better able to invade surrounding organs -- a characteristic feature of cancer cells.

Subsequently, the DKFZ researchers studied the question of whether the findings obtained in cancer cells in the culture dish are also involved in breast cancer. Studying tumor tissue samples of 76 patients, the team discovered that tumors which have already spread to the lymph nodes produce less miR-520 than those which have not yet spread. However, this connection was only found in tumors that do not produce receptors for the female sexual hormone, estrogen (ER-negative tumors).

"Our findings clearly demonstrate that miR-520 is a genuine cancer brake that suppresses the malignant behavior of tumor cells in two different ways at once," said Stefan Wiemann, commenting on the findings reported in his now published work. "This cancer brake appears to fail in many ER-negative breast tumors -- and also in cells of other types of cancer, as colleagues have now demonstrated." ER-negative breast cancer is particularly difficult to treat in many cases. Developing a microRNA therapy that blocks several cancer-promoting signaling pathways at once may therefore be an interesting option.


Story Source:

The above story is based on materials provided by Helmholtz Association of German Research Centres. Note: Materials may be edited for content and length.


Journal Reference:

  1. I Keklikoglou, C Koerner, C Schmidt, J D Zhang, D Heckmann, A Shavinskaya, H Allgayer, B Gückel, T Fehm, A Schneeweiss, Ö Sahin, S Wiemann, U Tschulena. MicroRNA-520/373 family functions as a tumor suppressor in estrogen receptor negative breast cancer by targeting NF-κB and TGF-β signaling pathways. Oncogene, 2011; DOI: 10.1038/onc.2011.571

Cite This Page:

Helmholtz Association of German Research Centres. "No brakes on breast cancer cells." ScienceDaily. ScienceDaily, 6 January 2012. <www.sciencedaily.com/releases/2011/12/111216112806.htm>.
Helmholtz Association of German Research Centres. (2012, January 6). No brakes on breast cancer cells. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2011/12/111216112806.htm
Helmholtz Association of German Research Centres. "No brakes on breast cancer cells." ScienceDaily. www.sciencedaily.com/releases/2011/12/111216112806.htm (accessed April 17, 2014).

Share This



More Health & Medicine News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) — A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Thousands Of Vials Of SARS Virus Go Missing

Thousands Of Vials Of SARS Virus Go Missing

Newsy (Apr. 16, 2014) — A research institute in Paris somehow misplaced more than 2,000 vials of the deadly SARS virus. Video provided by Newsy
Powered by NewsLook.com
Formerly Conjoined Twins Released From Dallas Hospital

Formerly Conjoined Twins Released From Dallas Hospital

Newsy (Apr. 16, 2014) — Conjoined twins Emmett and Owen Ezell were separated by doctors in August. Now, nearly nine months later, they're being released from the hospital. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Now Linked To 121 Deaths

Ebola Outbreak Now Linked To 121 Deaths

Newsy (Apr. 15, 2014) — The ebola virus outbreak in West Africa is now linked to 121 deaths. Health officials fear the virus will continue to spread in urban areas. Video provided by Newsy
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