Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New way to target – and kill – proliferating tumors

14.11.2011
UC San Diego researchers find surprising role for enzyme in tumor cell division and new drug to combat it

Researchers at the University of California, San Diego School of Medicine and the UC San Diego Moores Cancer Center have identified a new drug discovery approach enabling the destruction of the most highly proliferative tumors.

The discovery, published in the Nov. 13 online issue of the journal Nature Medicine, points to an effective, alternative method for killing fast-growing cancer cells without causing some of the negative effects of current therapies.

The scientists, led by David A. Cheresh, PhD, professor of pathology and associate director for translational research at the Moores Cancer Center, used an innovative chemical and biological approach to design a new class of drugs that arrests division in virtually all tumor cells by binding to and altering the structure of an enzyme called RAF.

RAF has been long-studied, but its role in cell division – critical to cell proliferation and tumor growth – was a surprise. "By designing a new class of drugs that changes the shape of RAF, we were able to reveal this previously undiscovered role for RAF in a wide range of highly proliferative tumors," Cheresh said.

Current cancer drugs that target enzymes like RAF are generally designed to interact with the active site of the enzyme. Unfortunately, these drugs often lack specificity, Cheresh said. "They hit many different targets, meaning they can produce undesired side effects and induce dose-limiting toxicity." More of a concern is that tumor cells often develop resistance to this class of drugs rendering them inactive against the cancer.

Cheresh and colleagues pursued development of a new class of RAF inhibitors that do not bind to the active site of the enzyme and so avoid the limitations of current drugs. Instead, this new class, called allosteric inhibitors, changes the shape of the target enzyme and in doing so, renders it inactive. The specific drug tested, known as KG5, singles out RAF in proliferating cells, but ignores normal or resting cells. In affected tumor cells, RAF is unable to associate with the mitotic apparatus to direct cell division, resulting in cell cycle arrest leading to apoptosis or programmed cell death. KG5 in a similar manner effectively interferes with proliferating blood vessels, a process called angiogenesis.

"It's an unusual discovery, one that really challenges current dogma," said Cheresh. "Before this drug was designed, we had no idea RAF could promote tumor cell cycle progression. This may be only one example of how, by designing drugs that avoid the active site of an enzyme, we can identify new and unexpected ways to disrupt the growth of tumors. In essence, we are attacking an important enzyme in a whole new way and thereby discovering new things this enzyme was intended for."

KG5 produced similar results in tests on cancer cell lines, in animal models and in tissue biopsies from human cancer patients. The research team has since developed variants of KG5 that are 100-fold more powerful than the original drug. They hope one of these more powerful compounds will soon enter clinical trials at Moores Cancer Center.

The new RAF targeted compounds are being developed by Amitech Therapeutic Solutions, Inc a start-up company in San Diego.

Co-authors of the study, all from the departments of Pathology or Radiation Oncology at the UC San Diego Moores Cancer Center, are Ainhoa Mielgo, Laetitia Seguin, Miller Huang, Fernanda Camargo, Sudarshan Anand, Aleksandra Franovic, Sara M. Weis, Sunil Advani and Eric Murphy.

Funding for this research came from the National Institutes of Health.

Scott LaFee | EurekAlert!
Further information:
http://www.ucsd.edu

Further reports about: Cancer Medicine blood vessel cancer drug cell cycle cell division tumor cells

More articles from Health and Medicine:

nachricht New antibody analysis accelerates rational vaccine design
09.08.2018 | Scripps Research Institute

nachricht Distrust of power influences choice of medical procedures
01.08.2018 | 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: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

Im Focus: World record: Fastest 3-D tomographic images at BESSY II

The quality of materials often depends on the manufacturing process. In casting and welding, for example, the rate at which melts solidify and the resulting microstructure of the alloy is important. With metallic foams as well, it depends on exactly how the foaming process takes place. To understand these processes fully requires fast sensing capability. The fastest 3D tomographic images to date have now been achieved at the BESSY II X-ray source operated by the Helmholtz-Zentrum Berlin.

Dr. Francisco Garcia-Moreno and his team have designed a turntable that rotates ultra-stably about its axis at a constant rotational speed. This really depends...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

'Building up' stretchable electronics to be as multipurpose as your smartphone

14.08.2018 | Information Technology

During HIV infection, antibody can block B cells from fighting pathogens

14.08.2018 | Life Sciences

First study on physical properties of giant cancer cells may inform new treatments

14.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>