In: Categories » Health » Cancer » What are Free Radicals and how do they contribute to Cancer
|
Free radicals are playing a role in gene mutations and oncogene overexpression. They are molecules that are unstable because they contain an unpaired electron. When a free radical molecule contacts the electrons of a stable molecule, the free radical molecule gains or loses electrons to achieve a stable paired-electron configuration. In the process, however, the electron balance of the stable molecule is disturbed, and the stable molecule becomes a free radical molecule. In this manner, free radicals initiate a chain reaction of destruction. Free radicals can damage DNA, protein, and fats. Indeed, free radical damage has been implicated as a major contributor to cancer, as well as to other degenerative diseases such as aging, cardiovascular disease, immune dysfunction, brain dysfunction, and cataracts. Free radicals can be produced by a variety of means. They can be produced by external factors such as radiation and cigarette smoke, and by internal events such as immune cell activity and cellular respiration (cellular “breathing” of oxygen). In humans, up to 5 percent of oxygen taken in is converted to free radicals during cellular respiration. During respiration, cells consume oxygen (O2) and produce water (H2O). By products of this process include the superoxide radical (O2), which can lead to the production of the very damaging hydroxyl radical (OH) (The dot represents unpaired electrons.) The hydroxyl radical is the most toxic of all the oxygen-based free radicals. Other important kinds of free radicals include the peroxyl and the alkoxyl radicals, both of which are involved in lipid peroxidation (oxidative damage to fats). In recent years, the term reactive oxygen species (ROS) has been adopted, since it includes the above-mentioned radicals plus hydrogen peroxide (H2O2) and molecular oxygen (O2). While not free radicals in themselves, these two can easily become free radicals in the body. The body maintains a variety of antioxidants as a multilevel defense against free radical damage. These include the enzymes superoxide dismutase, catalase, and glutathione peroxidase; antioxidants synthesized in the body, such as glutathione, proteins, and uric acid; and antioxidants obtained from the diet, such as flavonoids, vitamins C and E, and beta-carotene. Nevertheless, antioxidant defenses are not perfect, and DNA is damaged regularly. There may be as many as 10,000 oxidative hits to DNA per cell per day in humans.12 The vast majority of these lesions are repaired by cellular enzymes. Those that are not repaired may progress toward neoplasia (the formation of cancer cells). Because of the continual bombardment of DNA and other tissues by free radicals, the body must obtain ample antioxidant supplies through the diet. Epidemiological studies support a protective role for dietary antioxidants by consistently reporting that populations who consume inadequate amounts of fresh fruits and vegetables are at a higher risk for cancer, heart disease, and other degenerative diseases. Not only can free radicals initiate cancer, they can also facilitate cancer progression. And in fact, multiple human tumor cell lines have been reported to produce ROS (especially hydrogen peroxide) in vitro.14 Under normal circumstances, few cells other than immune cells produce hydrogen peroxide. Free radical production by tumor cells may help them mutate or display other malignant properties such as tissue invasion. For example, superoxide radicals have been reported to increase the invasive capacity of rat liver cancer cells in vitro. To be clear though, free radicals are not always bad. Only when they are overproduced or the body’s antioxidant system is overwhelmed do they cause problems.
|
legal disclaimer
1) Our website is not responsible for the information contained by this article as well for any and all copyright infringements by authors and writers. E-articles is a free information resource. If you suspect this article for any copyright infringements, please read the Terms of service and contact us to investigate the problem.
2) The E-articles directory team is not responsible for inaccuracies, falsehoods, or any other types of misinformation this tutorial may contain and will not be liable for any loss or damage suffered by a user through the user's reliance on the information gained here. Please read the Terms of service
Useful tools and features
If you like this article (tutorial), please link to it from your web page using the information above. Linking to this page, this is the only way to help us improve our service, the same time providing your visitors with a way to improve their online experience.
related articles
Cell differentiation is a measure of the maturity of a cell. Cells that are fully differentiated (fully mature) resemble their parent cells in form and function, and they proliferate very slowly, if at all. In contrast, immature cells are poorly differentiated, do not yet resemble their parents, and are able to proliferate at a higher rate. Most cancer cells are less differentiated, less mature, than normal cells, allowing cancer cells to proliferate readily. The degree to which a cell differentiates is re...
2. SEVEN STRATEGIES FOR CANCER INHIBITION
To be clear, not all cancers develop exactly as in the scenario above. This scenario is common, however, and within it lies the foundation for all our discussions on cancer inhibition. From it, we can identify seven clusters of procancer events: 1. Induction of genetic instability. Each cancer cell carries within itself genetic instability, and this instability increases the chances the cell will be able to mutate as needed to adapt to its environment. 2. Abnormal expression of genes. ...
3. DEVELOPMENT OF CANCER AND CHARACTERISTICS OF CANCER CELLS
Imagine a healthy tissue containing thousands of cells. Each cell serves the greater good, which is the continuation of a person’s life. Each cell is programmed so that when the cell is old or no longer needed, it dies a peaceful and timely death. This death is called apoptosis. All cells are in communication, which allows for the smooth repair and replacement of tissues and other aspects of cell behavior. Communication takes place either indirectly, via exchange of messenger compounds such as hormon...
4. How antioxidant vitamins and minerals protect your body
Since the antioxidant vitamins tend to obtain the major part of the pressure and publicity, much of people are unaware of that there are also important antioxidant minerals which are essential with the continuous battle of the body against the free radicals and the damage that they. To make sure that the suitable food is consumed daily is a part necessary to help the body to be able to also low keep damage of free radical like possible. An mineral, the vitamin or any other food is considered antioxidant if it, only or as an essential ...
Are you afraid of writing a cancer research paper? Relax! Now writing a paper is no more a nightmare as, many companies provide personalized and professional writing services. A custom paper is assigned to students so that they can have a deep insight into a particular subject matter and can widen their area of understanding too. Students are also made to write the paper so that they can develop meticulous knowledge about the same. Comprehensive and informative paper fetch more marks and helps students to improve their grades. ...
6. Mesothelioma Treatment
There are several methods of treatment for mesothelioma although none of them have a high success rate. In general, the chances of curing a patient mesothelioma depends on how much the cancer has grown and matured processed. If tackle in its infancy, there is a good chance of survival. Because of the difficulty of diagnosis of mesothelioma in its infancy, many mesothelioma treatments focus on improving the quality of life of patients. Before a patient is being treated then the doctor will determine the best method of treatment is by conside...
7. URINARY SEPTICAEMIA: TREATMENT
Sepsis as a result of a urinary tract infection is a serious condition that can lead to septic shock and death. Septicaemia or sepsis is the clinical syndrome caused by bacterial infection of the blood, confirmed by positive blood cultures for a speci.c organism. There should be a documented source of infection with a systemic response to the infection. The systemic response is known as the systemic inflammatory response syndrome (SIRS) and is de.ned by as at least two of the following: - Fever (>38°C) o...
8. Understanding the Mesothelioma Cause
Mesothelioma cause refers to the thing or event responsible for cancer mesothelioma. It is a cancer of the lining of the abdominal organs, lungs and heart. Almost all cases of mesothelioma some disease or the other are associated with exposure to asbestos particles. Exposure to asbestos particles could cause mesothelioma, even if the level of exposure is very low. Studies show that approximately 70 to 80% of all cases of mesothelioma have a history of exposure to asbestos and the identification of asbestos most important cause mesothelioma. Sur...
9. Relation Between Mesothelioma Lung Cancer and Asbestos Exposure
A good understanding of asbestos is necessary before attempting to understand lung cancer, mesothelioma. Asbestos, a natural mineral fiber, commonly used in the construction and manufacturing industries is detrimental to human health. Continuous inhalation of its fibers increases susceptibility to respiratory diseases and can lead to many dangerous diseases. A prime example of this dangerous disease is Mesothelioma lung cancer. In fact, lung cancer, mesothelioma is a misnomer because mesothelioma incidence of cancer of the lining of the lungs (...
10. The Facts About Pleural Mesothelioma
Mesothelioma cancer is the most common form of mesothelioma by far, and represents 75% of all cases. Prostate cancer affects the respiratory areas of the body, such as the lungs. Specifically, the attacks against cancer of the lining of the lungs and pleura called coasts hence the name pleural mesothelioma. The main cause of pleural mesothelioma is exposure to asbestos. What few months to be exposed to the deadly dust and asbestos fibers without protection can cause pleural mesothelioma thirty to fifty years later. The men aged sixty to s...