Featured Research

from universities, journals, and other organizations

Major source of cells' defense against oxidative stress identified

Date:
April 6, 2012
Source:
University of Southern California
Summary:
New research on a protein that protects cancer and other cells from oxidative stresses could one day help doctors to break down cancer cells' defenses, making them more susceptible to treatment.

Both radiation and many forms of chemotherapy try to kill tumors by causing oxidative stress in cancer cells. New research from USC on a protein that protects cancer and other cells from these stresses could one day help doctors to break down cancer cells' defenses, making them more susceptible to treatment.

In the March 23 issue of the Journal of Biological Chemistry, scientists led by USC Professor Kelvin J. A. Davies demonstrated that a protein known as Nrf2 governs a cell's ability to cope with oxidative stress by increasing the expression of key genes for removing damaged proteins.

Typically, oxidative stress is to be avoided. People eat foods high in antioxidants (such as fruits and vegetables) to try to block oxidation in their cells, in hopes of lowering their risk of illnesses such as cancer, heart disease, stroke and Alzheimer disease -- which are all linked to oxidative stress.

But in the case of cancer cells, if the Nrf2 response could some day be selectively turned off, treatments like chemotherapy and radiation could be more effective, Davies said.

"One of the problems you have is that cancer cells start becoming resistant to those treatments: they adapt," said Davies, who holds joint appointments in the USC Davis School of Gerontology the USC Dornsife College of Letters, Arts and Sciences. "The next time they may be more resistant because they've seen it before."

Nrf2 is a transcription factor protein, meaning that it binds to specific sequences of DNA, turning on the process of copying the blueprints encoded in those DNA sequences into functional enzymes. In particular, the new work from the Davies lab shows that production of proteasome and a proteasome regulator (Pa28) is controlled by Nrf2 during oxidative stress. Proteosome, in turn, is a large protein enzyme that breaks down oxidized proteins that would otherwise accumulate and cause cells to die.

When oxidative stress increases (simulated in the lab by adding hydrogen peroxide -- the major product of both radiation therapy and chemotherapy), Davies and his team found that the Nrf2 in a cell starts ramping up proteasome production.

The researchers then tested their findings by blocking Nrf2 with various chemical and genetic inhibitors, which in turn decreased the cell's ability to make more proteasome and cope with the hydrogen peroxide.

In normal young cells, Nrf2 allows continuous regulation of proteasome production in response to changing oxidative environments. This ability may decline in aging and age-related diseases, making older individuals less able to cope with stress.

"We would like to be able to reverse this decline in normal cells, while making cancer cells less stress-resistant and more easily killed by radiation therapy and chemotherapy," Davies said.

This research was supported by the National Institutes of Health/National Institute of Environmental Health Sciences.


Story Source:

The above story is based on materials provided by University of Southern California. Note: Materials may be edited for content and length.


Journal Reference:

  1. A. M. Pickering, R. A. Linder, H. Zhang, H. J. Forman, K. J. A. Davies. Nrf2-dependent Induction of Proteasome and Pa28 Regulator Are Required for Adaptation to Oxidative Stress. Journal of Biological Chemistry, 2012; 287 (13): 10021 DOI: 10.1074/jbc.M111.277145

Cite This Page:

University of Southern California. "Major source of cells' defense against oxidative stress identified." ScienceDaily. ScienceDaily, 6 April 2012. <www.sciencedaily.com/releases/2012/04/120406141757.htm>.
University of Southern California. (2012, April 6). Major source of cells' defense against oxidative stress identified. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2012/04/120406141757.htm
University of Southern California. "Major source of cells' defense against oxidative stress identified." ScienceDaily. www.sciencedaily.com/releases/2012/04/120406141757.htm (accessed October 21, 2014).

Share This



More Health & Medicine News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

CDC Revamps Ebola Guidelines After Criticism

CDC Revamps Ebola Guidelines After Criticism

Newsy (Oct. 21, 2014) The Centers for Disease Control and Prevention have issued new protocols for healthcare workers interacting with Ebola patients. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Vaccine Trials to Start a in January

WHO: Ebola Vaccine Trials to Start a in January

AP (Oct. 21, 2014) Tens of thousands of doses of experimental Ebola vaccines could be available for "real-world" testing in West Africa as soon as January as long as they are deemed safe in soon to start trials, the World Health Organization said Tuesday. (Oct. 21) Video provided by AP
Powered by NewsLook.com
First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

Newsy (Oct. 21, 2014) A medical team has for the first time given a man the ability to walk again after transplanting cells from his brain onto his severed spinal cord. Video provided by Newsy
Powered by NewsLook.com
CDC Issues New Ebola Guidelines for Health Workers

CDC Issues New Ebola Guidelines for Health Workers

Reuters - US Online Video (Oct. 21, 2014) The U.S. Centers for Disease Control and Prevention has set up new guidelines for health workers taking care of patients infected with Ebola. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins