Oxidative DNA Damage Repair

DNA is a nucleic acid that has the genetic instructions which all living organisms use to function except for RNA viruses. Oxidative stress on the other hand is a discrepancy between the production of reactive oxygen species and an organism’s ability to biologically facilitate detoxification or repair the resultant damage. This oxidative stress can cause DNA damage. Researchers have however discovered how such DNA is repaired and this makes the possibility of less invasive cancer treatment options achievable. Oxidative stress causes a variety of diseases especially when the body is exposed to electrically charged oxygen compounds. Such diseases include diabetes, arteriosclerosis and many types of cancer. The sources of these compounds include metabolic processes, exposure to X-rays or UV light. Disease manifests when the body’s defenses are overpowered and the aggressive oxygen compounds destroy genetic material. This process leads to the formation of 8-oxo-guanine base mutations which are harmful. Enni Markkanen from the University of Zurich in partnership with the University of Oxford decoded the mechanism of DNA repair. Organisms achieve this by copying thousands of 8-oxo-guanines without their harmful mutations. The researchers give a detailed outline of the mechanism in a publication in “PNAS” including its temporal and local coordination. The researchers expect that less invasive approaches to cancer therapy will be developed thanks to the discovery of this repair mechanism. In addition, early detection of cancer is also expected to become more efficient. A study coordinated by the researchers and the University Hospital Zurich, currently underway, is aimed at examining different samples of cancerous tissue so as to understand their repair genes and mechanisms of regulation.

The sequence of the human genome, the nature of DNA and our understanding of inherited and acquired diseases from their genetic basis has made curing these diseases a possibility. Genetic diseases are now treated by modulating the host’s genome. Previously, this was achieved through gene replacement but now, with this discovery, gene repair will prove to be even more effective as highlighted in the article. Understanding the mechanism of DNA repair will aid in cancer treatment since the risk of cancer is associated with inherited mutations that influence DNA repair genes. For instance, breast cancer is associated with two mutations, namely BRCA1 and BRCA2, which are associated with multiple repair pathways. The understanding of the DNA repair pathway will increase the effectiveness of therapeutic procedures that work by overpowering the ability of the cell to repair DNA damage, hence causing the death of such cells. It will also help doctors giving the treatment localize it to the cancer affected cells and not other rapidly dividing cells, for instance stem cells. Patients suffering from diseases associated with diminished DNA repair function will also be beneficiaries. These diseases include Bloom’s syndrome, Werner’s syndrome and Ataxia telengiectasia. The later causes increased sensitivity to some chemical agents and ionizing radiation. “Segmental progerias” is the term used to define this group of diseases since the patients suffer from aging-associated diseases and they appear elderly at a very young age. Finally, there is hope for patients with xeroderma pigmentosum. In this disease, repair of sunlight-induced DNA damage is defective. In addition, there is a high occurance of basal cell carcinoma. The discovery of the DNA repair mechanism will facilitate the development of therapeutic techniques that will hasted the repair of photo-damaged DNA and relieve these patients of their suffering. With a discovery that holds this much promise the only question that can be asked is “how effectively will the discovery of the DNA mechanism change human health?”