Journal of Pharmacy And Bioallied Sciences

DENTAL SCIENCE - REVIEW ARTICLE
Year
: 2015  |  Volume : 7  |  Issue : 5  |  Page : 197--199

DNA adducts-chemical addons


TR Rajalakshmi1, N AravindhaBabu1, KT Shanmugam2, K. M. K. Masthan1,  
1 Department of Oral Pathology, Sree Balaji Dental College and Hospital, Chennai, Tamil Nadu, India
2 Department of Oral Pathology, Madha Dental College, Chennai, Tamil Nadu, India

Correspondence Address:
Dr. T R Rajalakshmi
Department of Oral Pathology, Sree Balaji Dental College and Hospital, Chennai, Tamil Nadu
India

Abstract

DNA adduct is a piece of DNA covalently bond to a chemical (safrole, benzopyrenediol epoxide, acetaldehyde). This process could be the start of a cancerous cell. When a chemical binds to DNA, it gets damaged resulting in abnormal replication. This could be the start of a mutation and without proper DNA repair, this can lead to cancer. It is this chemical that binds with the DNA is our prime area of concern. Instead of performing the whole body analysis for diagnosing cancer, this test could be carried out for early detection of cancer. When scanning tunneling microscope is used, the DNA results can be obtained earlier. DNA adducts in scientific experiments are used as biomarkers.



How to cite this article:
Rajalakshmi T R, AravindhaBabu N, Shanmugam K T, Masthan K. DNA adducts-chemical addons.J Pharm Bioall Sci 2015;7:197-199


How to cite this URL:
Rajalakshmi T R, AravindhaBabu N, Shanmugam K T, Masthan K. DNA adducts-chemical addons. J Pharm Bioall Sci [serial online] 2015 [cited 2019 Dec 13 ];7:197-199
Available from: http://www.jpbsonline.org/text.asp?2015/7/5/197/155901


Full Text

Oral Cancer is one of the major threats to public health of developing countries in the world. In developed countries, cancer is the second most common cause of death. Among cancers, squamous cell carcinoma of the oral cavity is one of the malignant neoplasms in India. [1],[2]

Cells are the basic living units. Cells divide and produce daughter cells that are very essential for the replacement of cells lost during the course of life. The process of cell division is a tightly regulated program and occurs in the body only to the extent needed in any meticulous situation. During the process of cell division, one cell may obtain some genetic mutation that would alter the cell division control mechanism of that cell. This transformed cell no longer listens to the control signals for cell division and may continue to divide and proliferate. This uncontrolled cell division and growth ultimately result in cancer.

Neoplasm means "new growth."

According to British oncologist Willis "a neoplasm is an abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of the normal tissue and persists in the same excessive manner even after the cessation of the stimuli which evoked the change."

Oral cancer is a malignant neoplasm in the oral cavity that occurs at an average age of 60 years, with a frequency higher in men than in women.

 Major Causes for Oral Cancer



SmokingAlcoholBetel nut chewing.

 Carcinogens in Oral Cancer



AcetaldehydeBenzopyrenediol epoxide (BPDE)Safrole.

 Mechanism of Action of Carcinogens in Oral Cancer



Smoking

Smoking cigarette causes cancers of the esophagus, larynx, oral cavity, lung, bladder and pancreas.

Cigarette smoke contains more than three dozen distinct chemical species considered to be tumorigenic in humans or animals, among the most prominent are polynuclear aromatic hydrocarbons such as BPDE, aka-arenes such as dibenzo-acridine, N-nitrosamines, aromatic amines, [3],[4] aldehydes, arsenic, nickel, and chromium. Some of these chemicals are capable of initiating tumors while others can promote the development of previously initiated cancers. [1]

Benzopyrenediol epoxide, an extremely carcinogenic metabolite, is produced by burning tobacco, which irreversibly attaches to cell's nuclear DNA, which may destroy the cell or cause genetic mutation. [5] If the mutation inhibits the programmed cell death, the cell can turn into a cancer cell. Tobacco smoking use may induce mutations in p53 and Rb tumor suppressor genes. [6]

Alcohol

Alcohol use is widespread in most communities worldwide and is the most common drug abuse.

Ethanol is absorbed rapidly through the gastric and duodenal mucosa and metabolized mainly in the liver before elimination.

Mechanism of carcinogenesis

Alcohol oxidizes to acetaldehyde via the enzyme alcohol dehydrogenaseConversion of acetaldehyde to acetate by the enzyme aldehyde dehydrogenaseThen, acetate is oxidized to produce fatty acids, carbon dioxide, and waterThe action of antidiuretic hormone allows the accumulation of aldehyde in the oral mucosa, which in turn affects the DNA and causes mutation.

Betel quid

Betel quid refers to a chewing mixture of betel nut/areca catechu nut, slaked lime, betel leaves, and gambir.

Betel nut contains nicotine and pyridine alkaloids respectively. These components do not induce cancer, but when slaked lime is added there is severe caustic damage to both epithelium and the underlying tissues.

Nitrosamine was reported to be an important carcinogen, and another chemical constituent is polyphenols. Polyphenol bind to protein readily. Thus, the chance of betel nut polyphenols binding to the cellular nuclear materials and leading to the changes in cellular proliferation.

DNA damage

When a chemical binds to DNA, the DNA becomes damaged and complete replication cannot occur to make the normal intended cell. This could be the start of a mutation and without proper DNA repair it can lead to carcinogenesis, the initiator of cancer [Figure 1].{Figure 1}

The presence of such an imperative indicates prior exposure to a potential carcinogen.

 DNA Adduct Test



ELISA test can be performed to evaluate DNA adduct levels. [7],[8],[9] scanning tunneling microscope (STM) is used in order to achieve the DNA adducts level earlier.

 Conclusion



Studies to date strongly suggest that smoking, alcohol, betel quid are important causes for oral cancer. Instead of performing the whole body analysis for diagnosing cancer, DNA adduct test can be performed to detect the cancer. Thus, DNA adduct helps as the biomarker. And the cancer can be treated and prevented at the earlier stages. The association between the DNA adducts and early detection of cancer with STM being the key factor as new emerging concepts with wide reaching ramification needs more evidence and research.

References

1La DK, Swenberg JA. DNA adducts: Biological markers of exposure and potential applications to risk assessment. Mutat Res 1996;365:129-46.
2Farmer P. "Biomarkers of exposure and effect for environmental carcinogens, and their applicability to human molecular epidemiological studies". Public Health Applications of Human Biomonitoring. U.S. EPA. Available from: www.digplanet.com/wiki/DNA_adduct. [Last retrieved on 2011 Jun 22].
3den Engelse L, van Benthem J, Scherer E. Immunocytochemical analysis of in vivo DNA modification. Mutat Res 1990;233:265-87.
4Gorelick NJ, Wogan GN. Fluoranthene-DNA adducts: Identification and quantification by an HPLC-32P-postlabeling method. Carcinogenesis 1989;10:1567-77.
5Vahakangas K, Haugen A, Harris CC. An applied synchronous fluorescence spectrophotometric assay to study benzo[a] pyrene-diolepoxide-DNA adducts. Carcinogenesis 1985;6:1109-15.
6van Schooten FJ, van Leeuwen FE, Hillebrand MJ, de Rijke ME, Hart AA, van Veen HG, et al. Determination of benzo[a] pyrene diol epoxide-DNA adducts in white blood cell DNA from coke-oven workers: The impact of smoking. J Natl Cancer Inst 1990;82:927-33.
7Hemminki K, Grzybowska E, Chorazy M, Twardowska-Saucha K, Sroczynski JW, Putman KL, et al. DNA adducts in human environmentally exposed to aromatic compounds in an industrial area of Poland. Carcinogenesis 1990;11:1229-31.
8Hemminki K, Randerath K, Reddy MV, Putman KL, Santella RM, Perera FP, et al. Postlabeling and immunoassay analysis of polycyclic aromatic hydrocarbons - Adducts of deoxyribonucleic acid in white blood cells of foundry workers. Scand J Work Environ Health 1990;16:158-62.
9Phillips DH, Hemminki K, Alhonen A, Hewer A, Grover PL. Monitoring occupational exposure to carcinogens: Detection by 32P-postlabelling of aromatic DNA adducts in white blood cells from iron foundry workers. Mutat Res 1988;204:531-41.