Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers discover why melanoma is so malignant

05.09.2005


About 60,000 Americans will be diagnosed with melanoma this year, says the American Cancer Society, and 10,000 of those cases will be fatal. If not caught in the early stages, melanoma can be a particularly virulent form of cancer, spreading through the body with an efficiency that few tumors possess. Now, researchers at Whitehead Institute for Biomedical Research have discovered one of the reasons why this particular skin tumor is so ruthless. Unlike other cancers, melanoma is born with its metastatic engines fully revved.



"Other cancers need to learn how to spread, but not melanoma," says Whitehead Member Robert Weinberg, senior author of the paper that will be published September 4 in the early online edition of the journal Nature Genetics. "Now, for the first time, we understand the genetic mechanism responsible for this."

Metastasis (the spread of disease to an unconnected body part) is a highly inefficient, multi-step process that requires cancer cells to jump through many hoops. The cells first must invade a nearby tissue, then make their way into the blood or lymphatic vessels. Next they must migrate through the bloodstream to a distant site, exit the bloodstream, and establish new colonies. Researchers have wondered why melanoma in particular is able to do this not only more efficiently than other cancers, but at a far earlier stage. This new study shows that as melanocytes--cells that protect the skin from sun damage by producing pigmentation--morph into cancer cells, they immediately reawaken a dormant cellular process that lets them travel swiftly throughout the body.


Central to this reawakened process is a gene called Slug (named after the bizarre embryo shape that its mutated form can cause in fruit flies). Slug is active in the neural crest, an early embryonic cluster of cells that eventually gives rise to a variety of cell types in the adult, including dermal melanocytes. In this early embryonic stage, Slug enables the neural crest cells to travel, and then settle, throughout the developing embryo.

"Slug is a key component of the neural crest’s ability to migrate," says Piyush Gupta, a MIT graduate student in Weinberg’s lab and first author on the paper. "Following its activation during embryonic development, Slug is shut off in adult tissues." But when skin cells in, say, an individual’s mole, become malignant, they readily reactivate Slug and gain the ability to spread--something that other cancers can spend decades trying to do.

Weinberg’s team demonstrated this through a number of experiments. In the first, they created models of various cancer types by introducing cancer-causing genes into normal human cells and then injecting the tumor cells underneath the skin of mice. Mice injected with breast cancer cells or with fibroblast (connective tissue) cancer cells developed tumors, but the tumors didn’t spread. Those injected with melanoma cells immediately developed invasive tumors throughout their body, spreading everywhere from the lungs to the spleen. This strongly supported the suspicion that melanoma is so metastatic in part due to properties intrinsic to melanocytes themselves, and not simply because it is external and thus uniquely exposed to environmental stresses.

For the second experiment, the team used microarray technology (chips covered with fragments of DNA that can measure gene levels) and found that Slug was expressed in human melanoma. "Really, this isn’t that surprising," says Gupta, "when you consider that melanocytes in the skin are direct descendants of the neural crest." In fact, Gupta points out that occasionally physicians discover that perfectly benign melanocytes will sometimes manage to migrate through a patient’s body into, say, the lymph nodes. This phenomenon isn’t related to cancer, but rather demonstrates the latent ability of melanocytes to travel

Finally, the research team found that when Slug was knocked out in melanoma cells, the cancer was unable to metastasize when placed into a mouse.

"This work is yet another demonstration of the notion that certain embryonic genes normally involved in transferring cells from one part of the body to another are also involved in enabling cancer cells to spread," says Weinberg, who is also a professor of biology at MIT.

David Cameron | EurekAlert!
Further information:
http://www.wi.mit.edu

More articles from Life Sciences:

nachricht New gene catalog of ocean microbiome reveals surprises
18.08.2017 | University of Hawaii at Manoa

nachricht Organ Crosstalk: Fatty Liver Can Cause Damage to Other Organs
18.08.2017 | Deutsches Zentrum für Diabetesforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New gene catalog of ocean microbiome reveals surprises

18.08.2017 | Life Sciences

Astrophysicists explain the mysterious behavior of cosmic rays

18.08.2017 | Physics and Astronomy

AI implications: Engineer's model lays groundwork for machine-learning device

18.08.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>