Connotation of Glutathione-S-Transferase Enzyme Expression (GST) and Glutathione (GSH) in Human Head and Neck Squamous Cell Carcinoma Cancer

Abstract

Introduction: A series of enzymes deliver protection from harmful injury by toxic chemicals. Among these, Glutathione-S-transferase (GST) is most imperative for detoxifying exogenous and endogenous substances to protect cells from the toxic effects of ROS. Reactive oxygen free radicals are implicated in the pathogenesis of a multistage process of head and neck carcinogenesis, which are proposed to cause DNA base alterations, strand breaks, damage to tumor suppressor genes and an enhanced expression of proto-oncogenes. Materials and Methods: This study was conducted in COMSATS institute of Information Technology Islamabad supported by a grant from Higher Education Commission, Islamabad (Pakistan). Results: In the present study, alterations of Glutathione S-transferase (GST) enzyme activity were investigated in 500 samples (cohort 1 containing 200 head and neck cancer blood samples along with 200 healthy controls and cohort II with 50 head and neck squamous cell carcinoma tissue samples along with 50 control tissues) by high performance liquid chromatography and ELISA techniques. The results specified that mean blood GSH levels were significantly reduced in head and neck squamous cell carcinoma patients (p<0.001) blood samplesas compared to respective controls. In contrast, the levels of GSH (p<0.05) were significantly elevated in head and neck squamous cell carcinoma tissues compared with adjacent cancer free control tissues. The Glutathione S-transferase (GST) enzyme activity, (p<0.05) were significantly reduced in head and neck squamous cell carcinoma patient’s compared to adjacent cancer-free control tissues. Conclusion: Our study suggests that dysregulation of glutathione (GHS) levels and Glutathione S-transferase (GST) enzyme activity in head and neck cancer may have potential to contribute to the pathogenesisof HNSCC malignancies. This Investigation of the expression of GST-activity and GSH levels may provide information for prediction of individual cancer risk and the anticipation of cancer.