ubiquinone and Carcinoma--Squamous-Cell

Low-molecular-weight antioxidants are some of the most efficient agents of the skin defense mechanism against environmental factors, such as cosmic rays, smoke, and pollutants. The total skin concentrations of hydrophilic ascorbic and uric acids, as well as lipophilic α-tocopherol, β-carotene, and ubiquinol-10 antioxidants were determined by an HPLC-EC detector from 18 biopsies of human nonmelanoma skin carcinomas and 18 biopsies from skin areas adjacent to carcinomas. No significant differences in the concentrations of lipophilic antioxidants in both carcinomas and normal-looking skin areas adjacent to carcinomas were observed. On the contrary, ascorbic and uric acid concentrations were found to be 18 and 36% lower in carcinomas than in normal-looking skin areas, respectively. No statistical significance was observed between antioxidant concentrations and age, sex, phototype, profession, site of tumor, frequency, and time of UV light exposure either. Accordingly the antioxidant concentrations in both cancerous skin and adjacent normal-looking areas were found to be much higher than in normal skin, in contrast to literature data.

Topics: Adult; Aged; Aged, 80 and over; alpha-Tocopherol; Antioxidants; Ascorbic Acid; beta Carotene; Carcinoma, Basal Cell; Carcinoma, Squamous Cell; Female; Humans; Male; Middle Aged; Molecular Weight; Skin; Skin Neoplasms; Ubiquinone; Uric Acid

Bleomycin (BLM) is an anti-cancer drug that can induce formation of reactive oxygen species (ROS). To investigate the association between up-regulation of antioxidant enzymes and coenzyme Q(10) (CoQ(10)) in acquired BLM resistance, one BLM-resistant clone, SBLM24 clone, was selected from a human oral cancer cell line, SCC61 clone. The BLM resistance of SBLM24 clone relative to a sub-clone of SCC61b cells was confirmed by analysis of clonogenic ability and cell cycle arrest. CoQ(10) levels and levels of Mn superoxide dismutase, glutathione peroxidase 1, catalase and thioredoxin reductase 1 were augmented in SBLM24 clone although there was also a mild increase in the expression of BLM hydrolase. Suppression of CoQ(10) levels by 4-aminobenzoate sensitized BLM-induced cytotoxicity. The results of suppression on enhanced ROS production by BLM and the cross-resistance to hydrogen peroxide in SBLM24 clone further demonstrated the development of adaptation to oxidative stress during the formation of acquired BLM resistance.

Topics: 4-Aminobenzoic Acid; Antibiotics, Antineoplastic; Bleomycin; Carcinoma, Squamous Cell; Catalase; Cell Cycle; Cell Line, Tumor; Cell Survival; Cysteine Endopeptidases; Drug Resistance, Neoplasm; Drug Synergism; Enzyme Assays; Humans; Hydrogen Peroxide; Mouth Neoplasms; Oxidants; Reactive Oxygen Species; Superoxide Dismutase; Ubiquinone; Up-Regulation; Vitamin B Complex