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 The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

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: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>