Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cancer drug target Chk1 may also be source of drug resistance

02.09.2005


New findings suggest balancing Chk1 activity will produce less toxic cancer drugs



A study published by The Burnham Institute in the September edition of Molecular Cell reports that a cell-cycle checkpoint protein, known to be activated by an important class of anticancer drugs, may play crucial roles in both the hampering of therapeutic actions and aiding cancer cells to "recover" and start dividing again after treatment with these drugs. The study is expected to help academic researchers and biotechnology and pharmaceutical companies design drugs that combat cancer using this checkpoint protein, but with fewer side effects.

Robert Abraham, Ph.D., former director of The Burnham Institute’s Cancer Center and now vice president for oncology research at Wyeth Pharmaceuticals, together with his colleagues, found that the Chk1 protein responds with cell-survival activity to stressful conditions induced by hypoxia and certain anticancer drugs. Furthermore these same conditions target Chk1 for eventual destruction. Ironically, stimulation of Chk1 triggers certain repair responses that fight cancer while the simultaneous degradation of Chk1 can allow cancer cells to escape drug-induced death and resume progressive tumor growth.


The study suggests the Chk1 protein is critical for ensuring the repair of mutations and other errors in DNA replication before they can alter the function of a cell. If not repaired, these errors can kill the cell when it attempts to divide and proliferate. In cancer cells, Chk1 is responds as a natural defense to the therapeutic damage done by radiation and chemotherapy and attempts to effect repair to DNA damage caused by the cancer therapy, thus makes the drug therapy less effective.

The researchers also found that the chemotherapy agent campthothecin (CPT), a clinically important anticancer agent, reduced the activity of the Chk1 protein. "These findings lend strong support to the idea that inactivation of Chk1 contributes to the antitumor activity of CPT by allowing cells bearing damaged DNA to progress through the cell cycle, leading to an unsuccessful and often lethal attempt to undergo cell division," said Abraham. "Combination therapy, which pairs a chemotherapy agent with an inhibitor of Chk1, may therefore be an effective strategy to increase the efficacy of certain anticancer drugs, and may well overcome clinical resistance to these drugs."

By studying the effects of radiation and other stresses on the pathway that normally regulate Chk1, the researchers discovered that the same pathway that activates Chk1 via phosphorylation by its regulatory enzyme, ATR, also marks Chk1 for eventual destruction.

"We expect this process prevents activated Chk1 from accumulating in normal cells and prevents abnormal cell proliferation," said Abraham. "ATR activates, but also destabilizes Chk1, which creates a homeostatic mechanism that balances the genome protective function of Chk1 with the process of cell proliferation. This is a new look at drug therapy. Textbook descriptions of ATR and Chk1 don’t describe this dual role."

"The findings also provide further insight into Chk1 activation and tumor sensitivity," Abraham added. "Cancer cells rely heavily on Chk1 for survival and proliferation under stressful environmental conditions. Instead of halting abnormal growth of cancer cells, drug therapy could in effect induce Chk1 natural activity to prevent cell death in cancer cells."

Collaborators on this publication include You-wei Zhang, Diane M. Otterness, and Gary Chiang from Dr. Abraham’s laboratory at The Burnham Institute; and Weilin Xie, and Franklin Mercurio of Celgene Corporation; and Yun-Cai Liu of La Jolla Institute for Allergy and Immunology.

Nancy Beddingfield | EurekAlert!
Further information:
http://www.burnham.org

More articles from Studies and Analyses:

nachricht New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg

nachricht Disarray in the brain
18.12.2017 | Universität zu Lübeck

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>