Oxidative DNA damage and repair after genotoxic treatment of head and neck cancer cells

Introduction: DNA repair is critical for cancer cells susceptibility to genetoxic treatment. Oxidative lesions are the most abundant from DNA damage caused by many drugs and radiation. In the present study we examined the level of oxidative DNA damage and the efficacy of its repair after head and neck squamous cell carcinoma (HNSCC) treatment with hydrogen peroxide, cisplatin, MNNG and γ-radiation. Material and methods: The cells form tissue biopsies of 37 cancer patients and 35 healthy donors were employed to this examination. DNA oxidative lesions were evaluated by alkaline single cell gel electrophoresis and probed by DNA repair enzymes endonuclease III (NthI) and formamidopyrimidine-DNA glycosylase (Fpg). Results: It was found that HNSCC cancer cells were sensitive to genotoxic treatment and displayed impaired repair of oxidative DNA lesions. It was also found that HNSCC cells were the most sensitive to γ-radiation especially cells from metastasis. Conclusions: Our results suggested that DNA repair of oxidative lesions might be critical for genotoxic susceptibility of HNSCC cells what in turn might affect an efficiency of head and neck cancer therapy. (Clin Exp Med Lett 2009; 50(1):5-10)

Keywords: DNA Repair, oxidative lesions, head and neck cancer, Comet Assay