8-hydroxy-2--deoxyguanosine and Papilloma

: Oxidant/antioxidant balance has been suggested as an important factor for initiation and progression of cancer. The objective of this study was to determine 8-hydroxydeoxyguanosine (8-OHdG) level as a marker of oxidative DNA damage, glutathione peroxidase (G-Px), and superoxide dismutase (SOD) activities as antioxidant activity, in sera from women with breast cancer.. : Forty-nine patients with malign breast tumor were included in the study. Blood samples were collected before the surgical operation. Serum level of 8-OHdG was measured with a competitive enzyme-linked immunusorbent assay kit, SOD, and G-Px activities were measured by spectrophotometric kits.. : 8-Hydroxydeoxyguanosine level and SOD activity were found to be increased in breast cancer group as compared with control group. Glutathione peroxidase activity in the breast cancer group was lower than those in the control group. The ratio of 8-OHdG/G-Px in breast cancer patients was found to be higher than those in the controls. There were correlations between 8-OHdG and CA19-9 (r = 0.77; P < 0.01); age and G-Px (r = -0.84; P < 0.05) in the breast cancer group.. : Data show that serum levels of 8-OHdG and SOD activities are higher in patients with breast cancer. Glutathione peroxidase activity is lower in the breast cancer group. Increased ratio of 8-OHdG/G-Px in breast cancer patients is the evidence for impaired oxidant/ antioxidant balance in breast cancer.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Breast Neoplasms; Carcinoma; Case-Control Studies; Deoxyguanosine; Female; Fibroadenoma; Glutathione Peroxidase; Humans; Middle Aged; Oxidative Stress; Papilloma; Superoxide Dismutase

Helicobacter pylori (H. pylori) infection has been associated with gastric carcinogenesis, but responsible and detail mechanisms are insufficient by the absence of adequate data. To obtain direct evidence regarding the carcinogenicity of H. pylori, we investigated the initiating and promoting activity of H. pylori water extract (HPE) in two-stage mouse skin carcinogenesis model. HPE treatment, as an initiation, significantly enhanced tumor formation compared with control group. Moreover, HPE treatment increased production of 8-hydroxydeoxyguanosine in epidermal cells and HPE-initiated/TPA-promoted papillomas demonstrated a point mutation of the Ha-ras gene. These results suggest an initiating activity of HPE on two-stage mouse skin carcinogenesis.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Alleles; Animals; Carcinogens; Cell Fractionation; Cocarcinogenesis; Codon; Deoxyguanosine; Disease Progression; DNA; DNA Adducts; DNA Damage; Female; Genes, ras; Helicobacter pylori; Luminescent Measurements; Mice; Mice, Inbred SENCAR; Oxidative Stress; Papilloma; Peroxidase; Point Mutation; Skin; Skin Neoplasms; Superoxides; Tetradecanoylphorbol Acetate; Water

The mouse skin tumor initiation-promotion model was used to investigate the protective effect of diet restriction in mechanistic and quantitative terms. A total of five groups of 14 male NMRI mice were initiated with 100 nmol 7,12-dimethylbenz[a]anthracene (DMBA) and promoted twice weekly with 2.5, 1.25, or 0.625 nmol 12-O-tetradecanoylphorbol-13-acetate (TPA). Food intake was ad libitum (all 3 TPA dose levels) or restricted to 70% (high and intermediate TPA dose levels). Time of appearance of the first papilloma was recorded for each mouse. Two weeks later, an osmotic minipump delivering 5-bromo-2'-deoxyuridine (BrdU) was implanted and the mouse was killed after 24 h. Cell proliferation in the epidermis was assessed by immunohistochemistry for BrdU incorporated into DNA. 8-hydroxy-2'-deoxyguanosine (8-OH-dG) in epidermal DNA was determined by HPLC/electrochemical detection. The median latency time (t50) for the appearance of skin papilloma in the high-, intermediate-, and low-dose TPA groups fed ad libitum was 9, 15.5, and 23.5 weeks, respectively. The diet-restricted groups (high and intermediate TPA dose) showed t50 values of 16 and 26 weeks. Therefore, diet restriction to 70% had approximately the same protective effect as reducing the dose of TPA by a factor of two. Both the rate of cell proliferation and the level of 8-OH-dG in the epidermis increased with the dose of TPA. Median values were increased 3- to 4-fold at the highest dose. In controls, but not in TPA-treated animals, diet restriction resulted in a decrease for both markers, by 25 and 40% for the labeling index for cell division and the level of 8-OH-dG, respectively. Both markers showed an inverse relationship with the median papilloma latency time. On an individual basis, the correlation was significant in some groups, but only for the labeling index. The data indicate that protection from the skin tumor-promoting effect of TPA by diet restriction could be based more on a reduction of the rate of cell division than on a reduction of oxidative DNA damage.

Topics: 8-Hydroxy-2'-Deoxyguanosine; 9,10-Dimethyl-1,2-benzanthracene; Animals; Body Weight; Carcinogens; Cell Division; Deoxyguanosine; Diet; DNA; DNA Damage; Immunohistochemistry; Male; Mice; Oxidative Stress; Papilloma; Skin Neoplasms; Tetradecanoylphorbol Acetate

The question was addressed whether the risk of cancer of an individual in a heterogeneous population can be predicted on the basis of measurable biochemical and biological variables postulated to be associated with the process of chemical carcinogenesis. Using the skin tumor model with outbred male NMRI mice, the latency time for the appearance of a papilloma was used as an indicator of the individual cancer risk. Starting at 8 weeks of age, a group of 29 mice was treated twice weekly with 20 nmol of 7,12-dimethylbenz[alpha]anthracene (DMBA) applied to back skin. The individual papilloma latency time ranged from 13.5 to 25 weeks of treatment. Two weeks after the appearance of the first papilloma in each mouse, an osmotic minipump delivering 5-bromo-2'-deoxyuridine was s.c. implanted and the mouse was killed 24 hr later. Levels of DMBA-DNA adducts, of 8-hydroxy-2'-deoxyguanosine, and various measures of the kinetics of cell division were determined in the epidermis of the treated skin area. The levels of 8-hydroxy-2'-deoxyguanosine and the fraction of cells in DNA replication (labeling index for the incorporation of 5-bromo-2'-deoxyuridine) were significantly higher in those mice that showed short latency times. On the other hand, the levels of DMBA-DNA adducts were lowest in animals with short latency times. The latter finding was rather unexpected but can be explained as a consequence of the inverse correlation seen for the labeling index: with each round of cell division, the adduct concentration is reduced to 50% because the new DNA strand is free of DMBA adducts until the next treatment. Under the conditions of this bioassay, therefore, oxygen radical-related genotoxicity and the rate of cell division, rather than levels of carcinogen-DNA adducts, were found to be of predictive value as indicators of an individual cancer risk.

Topics: 8-Hydroxy-2'-Deoxyguanosine; 9,10-Dimethyl-1,2-benzanthracene; Animals; Cell Division; Deoxyguanosine; DNA; DNA Adducts; DNA Damage; DNA Replication; Immunohistochemistry; Kinetics; Male; Mice; Mice, Inbred Strains; Papilloma; Skin; Skin Neoplasms; Time Factors