Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Estrogen-Dependent Switch Tempers Killing Activity of Immune Cells

12.08.2009
The sex hormone estrogen tempers the killing activity of a specific group of immune cells, the cytotoxic T cells (CTLs), which are known to attack tumor cells and cells infected by viruses.

The key player in this process is a cytotoxic T cell molecule which has been known for a long time and which scientists have named EBAG9. Cancer researchers Dr. Constantin Rüder and Dr. Armin Rehm together with immunologist Dr. Uta Höpken of the Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch and Charité – University Medicine Berlin, Germany, have now unraveled the function of EBAG9. Modulated by estrogen, EBAG9 tempers the activity of CTLs. In the absence of EBAG9, the activity of CTLs is enhanced (Journal of Clinical Investigation, Vol. 119, No. 8, pp 2184-2203, August 3, 2009)*.

The sex hormone estrogen plays a critical role in the regulation of growth and the development of cells. It is also crucial for cell-type-specific gene expression in various tissues. Deregulation of this system results in breast and ovarian cancer.

Those tumors are successfully treated with drugs such as tamoxifen. Researchers suggest that this drug inhibits tumor growth by blocking the estrogen receptors of the tumor cells. However, up to now it has been unclear what effect this inhibition has on the immune system.

In a previous study, Japanese researchers detected large amounts of EBAG9 in estrogen-dependent tumors. Dr. Rehm and his colleagues wondered what effect elevated levels of estrogen would have on cytotoxic T cells that attack tumors. They assumed that EBAG9 could transmit this effect of estrogen and therefore wanted to know what would happen if they knocked out the gene for EBAG9 in mice.

After knocking out the gene for EBAG9, they found that in the absence of EBAG9 the “brake” of the immune cells is loosened. The immune cells can release much more of the tumor-killing enzymes than in the presence of EBAG9. The deathly harbingers are stored in granules (secretory lysosomes) in the cytotoxic T cells. They have greater quantities of these granules at their disposal once the blockage of the immune cells through EBAG9 is lifted.

These findings of the researchers in Berlin may also explain why drugs like tamoxifen act on tumor cell growth. One argument is that once the estrogen receptors of the tumor cells are inhibited by the drug, the sex hormone can no longer promote tumor growth. At the same time EBAG9 can no longer inhibit the cytotoxic T cells. The immune cells are ready to attack and destroy the tumor cells.

“In this way, tamoxifen not only inhibits tumor growth but may also be able to enhance the effect of the immune system,” Dr. Rehm said. His working hypothesis is that EBAG9 acts as a molecular switch which regulates the immune cells.

As a next step, he and his colleagues plan to study cytotoxic T cells from patients with estrogen-dependent tumors to see if EBAG9 levels are increased.

*The tumor-associated antigen EBAG9 negatively regulates the cytolytic capacity of mouse CD8+ T cells

Constantin Rüder,1 Uta E. Höpken,1 Jana Wolf,1 Hans-Willi Mittrücker,2 Boris Engels,1 Bettina Erdmann,1 Susanne Wollenzin,1 Wolfgang Uckert,1 Bernd Dörken,1,3 and Armin Rehm1,3

1Max Delbrück Center for Molecular Medicine, Berlin, Germany. 2Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.3Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany.


Barbara Bachtler
Press and Public Affairs
Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch
Robert-Rössle-Straße 10; 13125 Berlin; Germany
Phone: +49 (0) 30 94 06 - 38 96
Fax: +49 (0) 30 94 06 - 38 33
e-mail: presse@mdc-berlin.de

Barbara Bachtler | EurekAlert!
Further information:
http://www.mdc-berlin.de/

More articles from Life Sciences:

nachricht Rutgers scientists discover 'Legos of life'
23.01.2018 | Rutgers University

nachricht Researchers identify a protein that keeps metastatic breast cancer cells dormant
23.01.2018 | Institute for Research in Biomedicine (IRB Barcelona)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Optical Nanoscope Allows Imaging of Quantum Dots

Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.

Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Rutgers scientists discover 'Legos of life'

23.01.2018 | Life Sciences

Seabed mining could destroy ecosystems

23.01.2018 | Earth Sciences

Transportable laser

23.01.2018 | Physics and Astronomy

VideoLinks Science & Research
Overview of more VideoLinks >>>