Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ras Gene Causes Cancer Via Different Pathways in Humans vs. Mice

15.08.2002


Finding May Present a New Target for Anti-Cancer Drugs



Researchers at the Duke Comprehensive Cancer Center have found that a known cancer-causing gene, Ras, may exert its influence through very different pathways in humans than in mice, a finding that could offer tantalizing new targets for anti-cancer therapy.

While studying the Ras, gene, Duke researchers unexpectedly found that it activates an obscure group of proteins in humans, but not in mice, in order to turn normal cells malignant. Yet many cancer treatments are based on data scientists derive from mouse models.


“Our study highlights a little-known pathway that appears to play a critical role in the ability of Ras, to transform human cells, but not mouse cells, to become tumorigenic,” said Christopher Counter, Ph.D., a cancer biologist at the Duke Comprehensive Cancer Center. “This pathway could present a new protein target for anti-cancer drugs in humans, and it reinforces the inherent differences between human and mouse cancers in terms of how they evolve.”

Results of the Duke study are being published in the Aug. 15, 2002, issue of Genes and Development.

The Duke researchers decided to study oncogenic Ras, one of the first genes found to be involved in human cancers, because it is associated with very different malignancies in humans than in mice. Ras is activated in one-third of all human cancers, and as high as 90 percent in specific cancers, like pancreatic. In mice, Ras is associated with breast, skin and lung cancers.

Despite these differences, it was assumed that Ras signals the same set of proteins in mice as it does in humans for cells to become cancerous. The Duke scientists challenged this assumption and studied, for the first time, how Ras transforms human cells.

Team members Nesrin Hamad, Ph.D., and Joel Elconin, M.D., set out to map how Ras communicates with various signaling pathways that, when over-activated, ultimately command cells to proliferate uncontrollably. The scientists placed human and mouse cells in laboratory dishes, genetically modified the cells to express mutated forms of Ras, then traced how the protein produced by the Ras gene promoted cells to transform.

As expected, Ras exerted its malignant effects in mice cells primarily through a protein called Raf, whose specific job is to modify a chain of additional proteins that direct the cell’s behavior to proliferate. Unexpectedly, Raf was not sufficient to turn normal human cells cancerous, the study found. Instead, in human cells the Ras gene appeared to activate a different protein pathway, called RalGEFs, to transform normal cells into cancer.

Little is known about RalGEFs, possibly because they have never been considered critical to human cancers, but researchers suspect that they may assist cells in ferrying molecules within and outside of cells -- a process called vesicle transport. How these functions relate to Ras’ ability to transform normal cells into cancers remains unknown, said Counter. Nevertheless, the Duke study clearly showed that RalGEFs were necessary for the ability of Ras to transform normal human cells, he added.

“We propose that there are multiple proteins that Ras signals through in order to transform human cells, but there are significant differences in the relative potency of each pathway between humans and mice” Counter said. “The Ras oncogene appears to exert its function in humans through a pathway that was largely ignored.”

Rebecca Levine | EurekAlert!
Further information:
http://cancer.duke.edu/
http://www.genesdev.org/

More articles from Health and Medicine:

nachricht The genes are not to blame
20.07.2018 | Technische Universität München

nachricht Targeting headaches and tumors with nano-submarines
20.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>