A drug discovery team at Genentech, Inc., has uncovered a chink in the molecular armor of Ras, the most commonly occurring oncogene, which is a gene that when mutated has the potential of causing cancer in humans.
The chink, binding pocket of "functional significance" on the Ras oncoprotein could provide the long-sought attack point for a therapeutic agent, making the "undruggable" Ras oncogene "druggable," the researchers reported at the American Society for Cell Biology's 51st Annual Meeting in Denver.
The first human oncogene to be identified, Ras is mutated in about 25% of all human tumors. For cancer patients, the presence of an activated Ras oncogene is a poor prognosis marker.
Ras has a molecular on-off switch, activated by the energy transfer molecule GTP. In the "on" position, the oncogene activates critical cell signaling pathways involving cell proliferation, cell migration and cell differentiation, all of which are in hyper-drive in tumors.
To develop a drug that would switch off Ras, scientists needed a binding site, an opening in the Ras oncoprotein to which the docking mechanism of a therapeutic molecule could attach.
At the ASCB meeting, Joachim Rudolph, Ph.D., Weiru Wang, Ph.D., and Guowei Fang, Ph.D., of Genentech, a member of the Roche Group, reported that they identified such a binding pocket by fragment-based lead discovery, a screening process that sorted through 3,300 small molecule compounds. Nuclear magnetic resonance (NMR) spectroscopy was used to pinpoint molecules with even a weak affinity for binding to Ras oncoproteins. The researchers identified 25 compounds, none of which knocked out the oncoprotein.
However, NMR spectroscopy revealed that the 25 compounds were binding to the same location on the Ras oncoprotein. The researchers determined that the binding pocket was not static but could be enlarged once the ligand from the small molecule engaged it, providing researchers an opening for engineering the next generation of compounds.
Fang said that even the weak ligands formed by these compounds interfered with the Ras oncoprotein by blocking an enzyme, abbreviated SOS, that is required for activating the oncoprotein.
"The small molecules identified here represent the first generation of Ras inhibitors that directly prevent Ras activation," Fang said.
Guowei Fang, Ph.D. Genentech, Inc. Fang.email@example.com 650-228-8497
Robin Snyder, Ph.D. Director, External Communications Genentech Corporate Relations 650.467.7152 firstname.lastname@example.org
John Fleischman American Society for Cell Biology email@example.com 513-929-4635 513-706-0212 (cell)
Cathy Yarbrough American Society for Cell Biology firstname.lastname@example.org 858-243-1814
Sunday, Dec. 4, 2011 5:35 to 5:55 p.m. Minisymposium: Chemical Biology: Probes and Therapeutics Presentation 24
John Fleischman | EurekAlert!
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
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...
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...
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,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy