Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Low dose radiation evades cancer cells’ protective ’radar’

06.10.2004


Kills more cells than high-dose radiation

A new study shows that lower doses of radiation elude a damage detection "radar" in DNA and actually kill more cancer cells than high-dose radiation. With these findings, scientists believe they can design therapy to dismantle this "radar" sensor allowing more radiation to evade detection and destroy even greater numbers of cancer cells.
Researchers at the Johns Hopkins Kimmel Cancer Center tested the low-dose radiation strategy on cultured prostate and colon cancer cell lines and found that it killed up to twice as many cells as high-dose radiation. The extra lethality of the low-dose regimen was found to result from suppression of a protein, called ATM* which works like a radar to detect DNA damage and begin repair.


Theodore DeWeese, M.D., who led the study, speculates that cells hit with small amounts of radiation fail to switch on the ATM radar, which prevents an error-prone repair process. DeWeese, who will present his evidence at the annual meeting of the American Society for Therapeutic Radiology and Oncology on October 5 in Atlanta, explains.

"DNA repair is not foolproof - it can lead to mistakes or mutations that are passed down to other generations of cells," explains DeWeese, chairman of the Department of Radiation Oncology and Molecular Radiation Sciences at Johns Hopkins. "A dead cell is better than a mutant cell, so if the damage is mild, cells die instead of risking repair."

Higher doses of radiation cause extreme DNA damage and widespread cell death, so the ATM damage sensor is activated to preserve as many cells as possible, protecting, ironically, the cancer cells under target for destruction by the radiation.

While the low-dose regimen works in cultured cells, it has not proved successful in humans. This has lead to effort by Hopkins scientists to study ways to use viruses that can deliver ATM-blocking drugs to the cells. Tests in animals are expected to begin soon.

In the current study, colon and prostate cancer cells lines were treated with either high levels of radiation or small amounts spread over many days. Low-level radiation is approximately 10 times more powerful than normal exposure, while high doses are 1,000 times stronger. Approximately 35 percent of colon cancer cells survived low-dose radiation as compared to 60 percent receiving high-dose. In prostate cancer cell lines, half of the cells survived low-dose radiation, while 65 percent remained in higher doses.

In the low-dose group, ATM activation was reduced by 40 to 50 percent. The researchers proved ATM inactivation was the culprit since low-dose irradiated cells fared better after ATM was reactivated with chloroqine, best known as a treatment for malaria.

"Tricking cancer cells into ignoring the damage signals that appear on its radar could succeed in making radiation more effective in wiping out the disease," says DeWeese.

This research was funded by the National Cancer Institute.

Research participants from Johns Hopkins include Spencer Collis, Julie Schwaninger, Alfred Ntambi, Thomas Keller, Larry Dillehay, and William Nelson.

Vanessa Wasta | EurekAlert!
Further information:
http://www.jhmi.edu
http://www.radonc.jhmi.edu
http://www.hopkinskimmelcancercenter.org

More articles from Studies and Analyses:

nachricht Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

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: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

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...

Im Focus: Quantum Particles Form Droplets

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>