Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Breast cancer: How tumor cells break free and form metastases

08.07.2008
When tumor cells acquire the capacity to move around and invade other tissues, there is a risk of metastases and cancer treatment becomes more difficult.

At the Institut Curie, CNRS Director of Research Philippe Chavrier and his group have just discovered how breast cancer cells break the bonds that tether them to the tumor. The basement membrane around the mammary gland is a barrier to the spread of cancer cells.

Three proteins in the tumor cells transport enzymes needed to perforate this barrier, and another protein puts these enzymes in the right place. These discoveries, published in the 16 June 2008 issue of The Journal of Cell Biology and in Current Biology on 8 July 2008, shed light on the early mechanisms of the formation of metastases in certain breast cancers. These findings constitute an essential step in the quest for the early identification of highly invasive tumors, or even the blocking of formation of metastases.

Tissues are generally formed by cells arranged side by side. Epithelial cells cover an outer surface, such as the skin or an organ such as the mammary gland, and remain tightly bound together. This cohesion is vital to the body’s functioning, and the epithelial cells remain in position in their original tissue until they die. Sometimes, though, they detach and move away, and while such migration is essential during embryonic development as cells give rise to new tissues, when tumor cells break loose this often heralds the formation of metastases.

When tumor cells break loose

Tumor cells accumulate errors, become totally anarchic, and flout all the rules. Some even become detached from the tumor through complex and poorly understood mechanisms. The Membrane and Cytoskeleton Dynamics Group headed by Philippe Chavrier(1) (UMR 144 CNRS/Institut Curie) has now shed new light on the way cells, in this case breast cancer cells, escape their shackles. The mammary gland is separated from the neighboring tissue by the basement membrane, which the tumor cells will have to cross before continuing on their way.

The cell first forms protrusions called invadopodia and anchors them in the basement membrane. These “feet” provide everything needed to breach the membrane. The tumor cells produce a whole range of proteases that degrade the proteins of the extracellular matrix that hems them in, part of which is the basement membrane. These proteases cut a hole in the basement membrane through which the cells can escape.

In a first publication, the researchers used a model of metastatic breast cancer cells to show that the proteins sec3, sec8 and IQGAP1 transport vesicles containing proteases to the invadopodia. Without sec3, sec8 and IQGAP1 the vesicles cannot be fastened to the ends of the invadopodia and so the cells fail to escape into the neighboring tissue. Before the proteases can degrade the membrane, they must first be released from the vesicles.

In a second publication, Philippe Chavrier and colleagues show that the protein Vamp7 fuses protease-containing vesicles with the membrane of tumor cells. Only then can the proteases at the ends of the invadopodia progressively erode the basement membrane of the mammary gland. Inactivation of Vamp7 greatly reduces the ability of the breast cancer cells to degrade the extracellular matrix.

So tumor cells can only escape from the mammary gland by accomplishing a whole series of modifications. Philippe Chavrier and his group have shown how they hijack cellular mechanisms to leave their original tissue, after which they can spread throughout the body and form metastases.

These discoveries may help to explain why certain breast cancers are more aggressive than others, or even to identify highly invasive tumors at an early stage. It is also conceivable that tumor invasion could be blocked by acting on the underlying mechanisms identified by Philippe Chavrier and colleagues.

Celine Giustranti | alfa
Further information:
http://www.jcb.org
http://www.current-biology.com/

Further reports about: Chavrier Membrane invadopodia mammary mechanisms metastases proteases vesicles

More articles from Life Sciences:

nachricht Molecular Force Sensors
20.09.2017 | Max-Planck-Institut für Biochemie

nachricht Foster tadpoles trigger parental instinct in poison frogs
20.09.2017 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>