Role of nitric oxide and antioxidant enzymes in the pathogenesis of oral cancer

Abstract

Background: Oral cancer is the leading malignancy in India. Nitric oxide and antioxidant enzymes play an important role in etiology of oral cancer. Therefore, the present study evaluates nitric oxide and antioxidant enzyme levels in healthy individual without tobacco habits (NHT, N=30) and healthy individuals with tobacco habits (WHT, n=90), patients with oral precancers (OPC, n=15) and oral cancer patients (n=126).Materials and Methods: Blood samples were collected from the subjects. NO 2 +NO 3 (nitrite+nitrate), superoxide dismutase (SOD) and catalase levels were estimated using highly specific spectrophotometeric methods. Statistical analysis was done by SPSS statistical software version 10.Results: Mean plasma NO 2 +NO 3 levels were elevated in patients with OPC and oral cancer patients as compared to the controls. Mean activities of erythrocyte SOD and catalase were higher in WHT than NHT. Erythrocyte SOD and catalase levels were higher in WHT and patients with OPC as compared to NHT. The erythrocyte SOD and catalase activities were lower in oral cancer patients than patients with OPC. The erythrocyte SOD activity was higher in advanced oral cancer than the early disease. Erythrocyte catalase activity was lower in poorly differentiated tumors than well and moderately differentiated tumors. Pearson's correlation analysis revealed that alterations in plasma NO 2 +NO 3 levels were negatively associated with changes in erythrocyte SOD activities. Conclusion:The data revealed that the alterations in antioxidant activities were associated with production of nitric oxide in oral cancer, which may have significant role in oral carcinogenesis.

Estimation of Superoxide Dismutase and Glutathione Peroxidase in Oral Submucous Fibrosis, Oral Leukoplakia and Oral Cancer - A Comparative Study

“…Earlier studies have shown that these habits have clastogenic and carcinogenic effects (Patel et al, 2009). The fundamental hypothesis is, free radicals damage the cellular materials which would result in triggering or transforming normal cells into malignant ones.…”

Targeting Nitric Oxide Signaling with nNOS Inhibitors As a Novel Strategy for the Therapy and Prevention of Human Melanoma

“…In the skin, serving as an important second messenger, NO-mediated signaling also contributes to UV-induced melanogenesis and pigmentation (47). Large quantities of NO have been detected in many types of cancer tissues, and the roles of NO in carcinogenesis, cell survival and proliferation, tumor growth, and metastasis have been well documented in nonmelanoma skin cancer and other tumors (1,46,48). Constitutive production of NO in melanoma results in increased proliferation, impaired immune response, and lymphangiogenesis, which has been associated with poor survival in patients (13,16,35).…”

Serum levels of Antioxidant in patients with Oral Squamous Cell Carcinoma: a preliminary study

“…[9] The results are in contrast to Khanna R, S. Syed Sultan Beevi who has stated that the levels of antioxidants are considerably decreased in cancer patients than normal individuals [17,19]. Patel J et al, found erythrocyte SOD activities to be significantly increased in OSCC than normal individuals with smoking habits and in patients with pre-cancerous lesions [2]. Gurudath S et al also found that Erythrocyte -SOD (E-SOD) and GPx levels were decreased in not only OSCC but oral leukoplakia and oral submucous fibrosis also [20].…”

“…Though the role of tobacco and areca nut is well established with their etiopathogenesis and mutative changes in the oral epithelium, newer research indicates that body's own defence has a pivotal role to play in progression and prognosis of oral cancer. Substantial evidence has established the carcinogenic role of Reactive Oxygen Species (ROS) in the initiation and promotion of cancer [2] ROS is a molecule or molecule fragments containing unpaired electrons in the valence shell that is capable of existing independently (free) [3]. The ROS produced in cells include hydrogen peroxide, hypochlorous acid, and free radicals such as the hydroxyl radical and the superoxide anion.…”