Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

MDC Researchers Solve Puzzle of B-Cell Lymphoma Development

24.09.2012
In the germinal centers of the lymphatic system B cells produce antibodies specific for the pathogen. However, most lymphomas derive from the B cells at the germinal centers.

Now, Dr. Dinis Pedro Calado and Dr. Klaus Rajewsky of the Max Delbrück Center (MDC) have identified subgroups of B cells in germinal centers in which the proto-oncogene Myc, a critical regulator of cellular proliferation, is highly activated.


In germinal centers (here: whithin the spleen of a mouse) immune cells learn to fight pathogens with high specificity. Dr. Dinis Calado and Dr. Klaus Rajewsky now identified subpopulations of B cells at the germinal centers which express the proto-oncogene Myc (red). They showed that Myc is essential for the formation and maintenance of germinal centers. Their findings have implications for the pathogenesis of B-cell lymphomas.

(Photo: Dinis Calado/ Copyright: MDC)

They showed that the Myc gene in these subpopulations is essential for the formation and maintenance of the germinal centers. Their findings also shed light on the origin of B-cell lymphomas derived from B cells at the germinal center (Nature Immunology, DOI:10.1038/ni.2418)*.

The Myc gene is a key regulator of cellular proliferation and is frequently involved in chromosomal translocations in human lymphomas derived from B cells at the germinal center reaction. Such translocations, seen in roughly 10 percent of diffuse large B-cell lymphomas and almost all cases of sporadic Burkitt lymphoma, juxtapose Myc and enhancers in immunoglobulin loci, leading to deregulated Myc expression.
These observations have puzzled researchers for many years because translocations of this gene can only take place in those cells where Myc is active. “However, Myc is thought not to be expressed in B cells at the germinal center reaction, the progenitors of most B-cell lymphomas,” Dr. Rajewsky said. So the question was: if B cells at the germinal center reaction do not express Myc, how can they give rise to B cell lymphomas carrying Myc translocations?

Germinal centers are located in the lymphatic organs such as the spleen, lymph nodes and Peyer’s patches in the intestinal wall. In the germinal centers the B cells are confronted with antigens and quickly proliferate. For the immune system to be able to cope with the huge variety of antigens, B cells must modify their DNA through mutation (somatic hypermutation) and recombination (class-switch recombination). However, the fast proliferation together with the ongoing DNA modifications may increase the occurrence of errors, which makes the malignant transformation of B cells at the germinal center reaction probable. “B-cell lymphomas are the most common type of human lymphoid malignancies. They mostly originate either from B cells at the germinal center reaction or from B cells that have passed through the germinal center reaction,” Dr. Calado and Dr. Rajewsky pointed out.

What then is the role of the Myc gene? How can Myc be highly activated through translocations in B-cell lymphomas although it is not active in healthy B cells of the germinal center reaction? Dr. Calado and Dr. Rajewsky have now found an answer to this question. They identified subpopulations of B cells located in the germinal centers in which the Myc gene is activated. They also showed that c-Myc is essential for the formation and maintenance of the germinal centers. When they knocked out the Myc gene in B cells they could show that germinal centers could not be formed or maintained.

“The MYC-positive germinal center B-cell subpopulations are probably at high risk for malignant transformation. Our work has direct implications for the understanding of the pathogenesis of human germinal center-derived B-cell lymphomas carrying MYC chromosomal translocations and therefore can contribute to a better understanding of how these lymphomas occur,” Dr. Calado and Dr. Rajewsky said.

*The cell-cycle regulator c-Myc is essential for the formation and maintenance of germinal centers

Dinis Pedro Calado1,2, Yoshiteru Sasaki3, Susana A. Godinho4, Alex Pellerin1, Karl Köchert2, Barry P. Sleckman5, Ignacio Moreno de Alborán6, Martin Janz2,7, Scott Rodig8, & Klaus Rajewsky1,2

1Program of Cellular and Molecular Medicine, Children's Hospital, and Immune Disease Institute, Harvard Medical School, Boston, Massachusetts, USA. 2Max Delbrück Center for Molecular Medicine, Berlin, Germany. 3Department of Molecular and Cellular Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan. 4Department of Pediatric Oncology, Dana-Farber Cancer Institute, Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA. 5Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA. 6Department of Immunology and Oncology, National Centre for Biotechnology, Madrid, Spain. 7Hematology, Oncology and Tumor Immunology, Charité, University Medical School, Berlin, Germany. 8Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA.

Contact:
Barbara Bachtler
Press Department
Max Delbrück Center for Molecular Medicine (MDC) Berlin-Buch
in the Helmholtz Association
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 | Max-Delbrück-Centrum
Further information:
http://www.mdc-berlin.de/

More articles from Life Sciences:

nachricht What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Simple processing technique could cut cost of organic PV and wearable electronics

06.12.2016 | Materials Sciences

3-D printed kidney phantoms aid nuclear medicine dosing calibration

06.12.2016 | Medical Engineering

Robot on demand: Mobile machining of aircraft components with high precision

06.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>