Science Current Events | Science News | Brightsurf.com
 

Scientists identify major source of cells' defense against oxidative stress

April 09, 2012
Research on how cells cope with stress could lead to more effective ways to weaken and kill cancer cells

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.

University of Southern California


Related Oxidative Stress Current Events and Oxidative Stress News Articles


Cholecystokinin octapeptide antagonizes apoptosis in retinal pigment epithelial cells
Oxidative stress may cause retinal pigment epithelial (RPE) cell apoptosis. Nitric oxide and superoxide react to produce peroxynitrite, which, along with its derivatives, are strong oxidants. Cholecystokinin octapeptide-8 (CCK-8) can protect cholinergic neurons against basal forebrain lesion caused by brain injury.

Single enzyme is necessary for development of diabetes
An enzyme called 12-LO promotes the obesity-induced oxidative stress in the pancreatic cells that leads to pre-diabetes, and diabetes.

Oxidative Stress Is Significant Predictor for Hip Fracture, Research Shows
Oxidative stress is a significant predictor for hip fracture in postmenopausal women, according to new research led by University of Cincinnati (UC) epidemiologists.

Treating Alzheimer's disease with Yizhijiannao granules by inhibiting neuronal apoptosis
Previous studies have shown that Yizhijiannao granule can enhance cognitive performance in Alzheimer's disease patients and Alzheimer's disease-model mice.

Analysis of African plant reveals possible treatment for aging brain
For hundreds of years, healers in São Tomé e Príncipe-an island off the western coast of Africa-have prescribed cata-manginga leaves and bark to their patients. These pickings from the Voacanga africana tree are said to decrease inflammation and ease the symptoms of mental disorders.

NUS study shows effectiveness of common anti-malarial drug in controlling asthma
Asthmatic patients may soon have a more effective way to control the condition, thanks to a new pharmacological discovery by researchers from the National University of Singapore (NUS).

Antioxidant Biomaterial Promotes Healing
When a foreign material like a medical device or surgical implant is put inside the human body, the body always responds.

BU researchers discover that Klotho is neuroprotective against Alzheimer's disease
Boston University School of Medicine researchers may have found a way to delay or even prevent Alzheimer's disease (AD).

Anti-pain agent shrinks oral cancers, leaves healthy tissues alone
Mouse models of human oral cancer treated with an agent called capsazepine showed dramatic tumor shrinkage without damage to surrounding tissues, researchers from the School of Dentistry and School of Medicine at The University of Texas Health Science Center at San Antonio found.

Strategies to preserve myelin during secondary degeneration following neurotrauma
Researchers at the University of Western Australia, led by Associate Professor Melinda Fitzgerald, have discovered that preventing abnormalities in the insulating sheath surrounding nerve cells is associated with better function following neurotrauma.
More Oxidative Stress Current Events and Oxidative Stress News Articles

Oxidative Stress: What is Oxidative Stress?

Oxidative Stress: What is Oxidative Stress?
by Matthew Jordan (Author)


The term oxidative stress has been linked to multiple diseases and aging. Oxidative stress and managing free radicals through antioxidants has also become big business and it is important that consumers educate themselves on effective oxidative stress management. This book will provide a simple definition of oxidative stress along with sources of oxidative stress management.

Molecular Basis of Oxidative Stress: Chemistry, Mechanisms, and Disease Pathogenesis

Molecular Basis of Oxidative Stress: Chemistry, Mechanisms, and Disease Pathogenesis
by Frederick A. Villamena (Author)


Sets the stage for the development of better diagnostic techniques and therapeuticsFeaturing contributions from an international team of leading clinicians and biomedical researchers, Molecular Basis of Oxidative Stress reviews the molecular and chemical bases of oxidative stress, describing how oxidative stress can lead to the development of cancer and cardiovascular and neurodegenerative diseases. Moreover, it explains the potential role of free radicals in both the diagnosis and the development of therapeutics to treat disease.Molecular Basis of Oxidative Stress is logically organized, beginning with a comprehensive discussion of the fundamental chemistry of reactive species. Next, the book:Presents new mechanistic insights into how oxidative damage of biomolecules occursExamines how...

Free Radicals in Biology and Medicine

Free Radicals in Biology and Medicine
by Barry Halliwell (Author), John Gutteridge (Author)


Free Radicals in Biology and Medicine has become a classic text in the field of free radical and antioxidant research since its first publication in 1985.

This latest edition has been comprehensively rewritten and updated (over 80% of the text is new), while maintaining the clarity of its predecessor. There is expanded coverage of isoprostanes and related compounds, mechanisms of oxidative damage to DNA and proteins (and the repair of such damage), the free radical theory of aging and the roles played by reactive species in signal transduction, cell death, human reproduction, and other important biological events. Greater emphasis has also been placed on the methods available to measure reactive species and oxidative damage (and their potential pitfalls), as well as the importance...

Liver Metabolism and Fatty Liver Disease (Oxidative Stress and Disease)

Liver Metabolism and Fatty Liver Disease (Oxidative Stress and Disease)
by Oren Tirosh (Editor)


Nonalcoholic fatty liver disease is one of the most common liver diseases worldwide affecting patients from all ages, races, and ethnic backgrounds. It comprises a spectrum of hepatic pathology ranging from simple steatosis, in which there is an increase of fat accumulation in hepatocytes, to nonalcoholic steatohepatitis and cirrhosis. The significant prevalence of this disease—between 15 and 45 percent of the general population—means that it contributes to an increased burden of ill health both today and in the future. Liver Metabolism and Fatty Liver Disease addresses the current understanding of the development of nonalcoholic fatty liver disease as well as the clinical aspects of the disease by examining the current knowledge surrounding metabolism in the liver. The book discusses...

Oxidative Stress in Aging: From Model Systems to Human Diseases (Aging Medicine)

Oxidative Stress in Aging: From Model Systems to Human Diseases (Aging Medicine)
by Satomi Miwa (Editor), Kenneth Bruce Beckman (Editor), Florian Muller (Editor)


Human aging is a complex phenomenon. This state-of-the-art book discusses the role of free radicals in aging in different animal models, as well as the relevance of free radicals on age-related diseases and pathological conditions in humans (following an introduction section of the basics and theory of free radicals). In addition, the major interventions trials of antioxidant supplements in age-related disease, cancer and so forth are reviewed and discussed.

Oxidative Stress, Exercise and Aging

Oxidative Stress, Exercise and Aging
by Helaine M. Alessio (Editor), Ann E. Hagerman (Editor)


This book brings together some of the leading researchers in the actively investigated field of oxidative stress, an area of study which is of importance to human health and disease. It examines oxidative stress in a variety of models, at rest and after exercise, in young and old. Key concepts of oxidative stress, exercise and aging are presented in clear and easy-to-understand terms. Oxidative stress in different types of exercises - isometric, isotonic and sports - is explained in detail, with several chapters focusing on acute and chronic adaptations of skeletal muscles following both aerobic and non-aerobic exercises. The book includes current knowledge of the underlying mechanisms influencing health and disease processes associated with oxidative stress.

Oxidative Stress and Hormesis in Evolutionary Ecology and Physiology: A Marriage Between Mechanistic and Evolutionary Approaches

Oxidative Stress and Hormesis in Evolutionary Ecology and Physiology: A Marriage Between Mechanistic and Evolutionary Approaches
by David Costantini (Author)


This book discusses oxidative stress and hormesis from the perspective of an evolutionary ecologist or physiologist. In the first of ten chapters, general historical information, definitions, and background of research on oxidative stress physiology, hormesis, and life history are provided. Chapters 2-10 highlight the different solutions that organisms have evolved to cope with the oxidative threats posed by their environments and lifestyles. The author illustrates how oxidative stress and hormesis have shaped diversity in organism life-histories, behavioral profiles, morphological phenotypes, and aging mechanisms. The book offers fascinating insights into how organisms work and how they evolve to sustain their physiological functions under a vast array of environmental conditions.

Oxidative Stress in Aquatic Ecosystems

Oxidative Stress in Aquatic Ecosystems
by Doris Abele (Editor), Jose Pablo Vazquez-Medina (Editor), Tania Zenteno-Savin (Editor)


Reactive oxygen species (ROS) are  increasingly appreciated as down-stream effectors of cellular damage and dysfunction under natural and anthropogenic stress scenarios in aquatic systems. This comprehensive volume describes oxidative stress phenomena in different climatic zones and groups of organisms, taking into account specific habitat conditions and how they affect susceptibility to ROS damage.A comprehensive and detailed methods section is included which supplies complete protocols for analyzing ROS production, oxidative damage, and antioxidant systems. Methods are also evaluated with respect to applicability and constraints for different types of research.The authors are all internationally recognized experts in particular fields of oxidative stress research.This comprehensive...

The Methuselah Project - How the science of anti-aging can help you live happier, longer and stronger

The Methuselah Project - How the science of anti-aging can help you live happier, longer and stronger


Half Price for a Limited Time - Normally $8.99!Do you want to harness the latest advances in science to build a blueprint for a long life?In what is by far his most comprehensive work to date, James Lee (author of "Brain 2.0" and "Brain Hacks") has trawled through the latest research journals (and some older, lesser known studies) to identify the sources of premature aging and what you can do to increase your chances of living to 100 and beyond. Anti-aging should go beyond just the "best anti-aging cream" and encompass every aspect of life-extension and healthy aging.Lee takes you through the work that scientists are currently undertaking to pin down exactly why it is we age and what can we do about it. Many scientists believe that there is no theoretical upper limit to lifespan that...

Adrenal Fatigue: The 21st Century Stress Syndrome

Adrenal Fatigue: The 21st Century Stress Syndrome
by James Wilson (Author), Jonathan V. Wright (Foreword)


This is an incredibly informative and reader-friendly book about a common debilitating medical condition that goes largely undiagnosed and untreated. ADRENAL FATIGUE: The 21st Century Stress Syndrome is a very empowering work cram-packed with vital information about a condition that very likely affects millions of people.

© 2014 BrightSurf.com