3-nitrotyrosine and Precancerous-Conditions

Hepatocellular carcinoma (HCC), one of the most frequent and deadliest cancers, has been increasing considerably in the United States. In the absence of a proven effective therapy for HCC, novel chemopreventive strategies are urgently needed to lower the current morbidity and mortality of HCC. Recently, we have reported that resveratrol, a compound present in grapes and red wine, significantly prevents diethylnitrosamine (DENA)-induced liver tumorigenesis in rats, although the mechanism of action is not completely understood. In the present study, we have examined the underlying mechanisms of resveratrol chemoprevention of hepatocarcinogenesis by investigating the effects of resveratrol on oxidative damage and inflammatory markers during DENA-initiated rat liver carcinogenesis. There was a significant increase in hepatic lipid peroxidation and protein oxidation in carcinogen control animals compared with their normal counterparts at the end of the study (20 weeks). Elevated expressions of inducible nitric oxide synthase and 3-nitrotyrosine were noticed in the livers of the same animals. Dietary resveratrol (50-300 mg/kg) administered throughout the study reversed all the aforementioned markers in a dose-responsive fashion in rats challenged with DENA. Resveratrol also elevated the protein and mRNA expression of hepatic nuclear factor E2-related factor 2 (Nrf2). Results of the present investigation provide evidence that attenuation of oxidative stress and suppression of inflammatory response mediated by Nrf2 could be implicated, at least in part, in the chemopreventive effects of this dietary agent against chemically induced hepatic tumorigenesis in rats. The outcome of this study may benefit the development of resveratrol in the prevention and intervention of human HCC.

Topics: Animals; Antioxidants; Carcinogens; Chemical and Drug Induced Liver Injury; Diethylnitrosamine; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Enzyme Induction; Female; Hyperplasia; Inflammation; Lipid Peroxidation; Liver; Liver Neoplasms, Experimental; NF-E2-Related Factor 2; Nitric Oxide Synthase Type II; Oxidative Stress; Phenobarbital; Precancerous Conditions; Rats; Rats, Sprague-Dawley; Resveratrol; RNA, Messenger; Stilbenes; Tyrosine

The molecular and cellular mechanisms linking chronic inflammation and gastrointestinal malignancy are not known with certainty.. To investigate changes in potential causative factors during progression of esophagus cancer in a population living in high-risk area in Iran.. Formalin-fixed, paraffin-embedded esophageal specimens (n=87) from patients with gastroesophageal reflux disease (GERD), Barrett's metaplasia, adenocarcinoma (ADC) and squamous cells carcinoma (SCC) were collected based on their pathological diagnosis.. Immunohistochemical (IHC) technique was used to study tissue accumulation of P53, P21, cyclooxygenase-2 (COX-2), glutathione S-transferase-P (GST-Pi) and nitrotyrosine (NT) in patients and controls.. P53 expression was not detected in esophageal tissues from normal and GERD samples, whereas it was found positive in Barrett's, ADC, and SCC samples. P21 positive sample was relatively higher in ADC patients as compared to that in SCC (ADC: 52.6%; SCC: 25%). GST-Pi expression was equally accumulated in all the samples. NT was predominantly expressed in ADC (72.7%). COX-2 expression was significantly higher in Barrett's (60.0%) and ADC (66.6%) as compared to that in GERD, SCC and normal. These data were further confirmed by detecting the scores of immunostainings in all the positive samples.. The pathological changes in ADC and SCC samples which were associated with increasing frequency of NT and COX-2 provides further evidence for involvement of these inflammatory factors in progression of esophagus cancer.

Topics: Adenocarcinoma; Adult; Aged; Aged, 80 and over; Barrett Esophagus; Biomarkers, Tumor; Carcinoma, Squamous Cell; Case-Control Studies; Cyclin-Dependent Kinase Inhibitor p21; Cyclooxygenase 2; Disease Progression; Esophageal Neoplasms; Esophagus; Female; Gastroesophageal Reflux; Glutathione S-Transferase pi; Humans; Immunohistochemistry; Iran; Male; Middle Aged; Precancerous Conditions; Tumor Suppressor Protein p53; Tyrosine; Young Adult

Oral leukoplakia is a premalignant lesion associated with development of oral cancer. To clarify the mechanism of development of oral carcinogenesis from leukoplakia, we examined DNA damage in oral epithelium of biopsy specimens of patients with leukoplakia by immunohistochemical methods. Histological changes, such as epithelial dysplasia and infiltration of inflammatory cells were observed in oral tissues of leukoplakia patients. A double immunofluorescence labeling study demonstrated that the accumulation of mutagenic 8-nitroguanine, an indicator of nitrative DNA damage, and 8-oxo-7,8-dihydro-2'-deoxyguanosine, an indicator of oxidative DNA damage, was apparently observed in the oral epithelium of patients with leukoplakia, whereas little or no immunoreactivity was observed in normal oral mucosa. Expression of inducible nitric oxide synthase (iNOS) was also observed in oral epithelium of leukoplakia patients. Immunoreactivity of 3-nitrotyrosine, an indicator of nitrative stress, was observed in oral epithelial cells and colocalized with 8-nitroguanine. Moreover, proliferating cell nuclear antigen and p53 were expressed in 8-nitroguanine-positive epithelial cells in the basal layer. These results suggest that iNOS-mediated nitrative stress contributes to development of oral carcinogenesis from leukoplakia through DNA damage as well as oxidative stress.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Biomarkers, Tumor; Deoxyguanosine; Female; Fluorescent Antibody Technique; Guanine; Humans; Leukoplakia, Oral; Male; Middle Aged; Mouth Mucosa; Nitric Oxide Synthase Type II; Oxidative Stress; Precancerous Conditions; Proliferating Cell Nuclear Antigen; Tumor Suppressor Protein p53; Tyrosine

Recent studies suggest that reactive oxygen (ROS) and nitrogen species (RNS) are highly associated with the pathogenesis of cigarette smoke related lung diseases but their role in the malignant conversion of bronchial epithelium is unclear. The immunohistochemical expression of inducible, endothelial and neuronal nitric oxide synthases (iNOS, eNOS and nNOS) and nitrotyrosine as a biomarker of oxidative/nitrosative stress was evaluated in 79 cases including 13 non-smokers, 20 smokers without chronic obstructive pulmonary disease (COPD), 22 with COPD and 24 with metaplasia-dysplasia-sequence of the bronchial epithelium. Normal lung of non-smokers was mainly negative for nitrotyrosine, while it was higher in the alveolar macrophages of cigarette smokers and COPD than in non-smokers (p=0.025, p<0.001), and in the alveolar epithelium of smokers and COPD than in non-smokers (p=0.049). There were no major differences in the nitrotyrosine immunoreactivity between the metaplastic/dysplastic lesions and bronchial epithelium of cigarette smokers. Inducible NOS and nNOS were mainly non-detectable or weak in the normal looking bronchial epithelium of smokers and COPD, whereas metaplasia and dysplasia showed positivity for iNOS (22/24) and nNOS (14/24) in the majority of cases. Strong immunoreactivity for iNOS and nNOS was also found more often in dysplastic than metaplastic (p=0.011 and p=0.049, respectively) specimens. Thus, smoking can cause protein nitration also in normal lung. Prominent iNOS and nNOS immunoreactivity in the metaplasia-dysplasia-lesions suggests a divergent role of NOSs in lung carcinogenesis.

Topics: Aged; Analysis of Variance; Biomarkers; Bronchi; Bronchoscopy; Cell Transformation, Neoplastic; Female; Humans; Immunoenzyme Techniques; Male; Middle Aged; Nitric Oxide Synthase; Nitric Oxide Synthase Type I; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Oxidative Stress; Precancerous Conditions; Pulmonary Disease, Chronic Obstructive; Smoking; Tyrosine

To investigate the extent of oxidative stress in pre-neoplastic and neoplastic gastric mucosa in relation to their pathological criteria and histological subtypes.. A total of 104 gastric adenocarcinomas from 98 patients (88 infiltrative and 16 intraepithelial tumors) were assessed immunohistochemically for expression of iNOS and occurrence of nitrotyrosine (NTYR)-containing proteins and 8-hydroxy-2'-deoxyguanosine (8-OH-dG)-containing DNA, as markers of NO production and damages to protein and DNA.. Tumor cells staining for iNOS, NTYR and 8-OH-dG were detected in 41%, 62% and 50% of infiltrative carcinoma, respectively. The three markers were shown for the first time in intraepithelial carcinoma. The expression of iNOS was significantly more frequent in tubular carcinoma (TC) compared to diffuse carcinoma (DC) (54% vs 18%; P = 0.008) or in polymorphous carcinoma (PolyC) (54% vs 21%; P = 0.04). NTYR staining was obviously more often found in TC than that in PolyC (72% vs 30%; P = 0.03). There was a tendency towards a higher rate of iNOS staining when distant metastasis (pM) was present. In infiltrative TC, the presence of oxidative stress markers was not significantly correlated with histological grade, density of inflammation, the depth of infiltration (pT), lymph nodes dissemination (pN) and pathological stages (pTNM).. The iNOS-oxidative pathway may play an important role in TC, but moderately in PolyC and DC. DNA oxidation and protein nitration occur in the three subtypes. Based on the significant differences of NTYR levels, TC and PolyC appear as two distinct subtypes.

Topics: Adenocarcinoma; Adult; Aged; Aged, 80 and over; Biomarkers; Carcinoma in Situ; Deoxyguanine Nucleotides; DNA, Neoplasm; Female; Gastric Mucosa; Humans; Immunohistochemistry; Male; Middle Aged; Neoplasm Proteins; Nitric Oxide; Nitric Oxide Synthase Type II; Oxidative Stress; Precancerous Conditions; Retrospective Studies; Stomach Neoplasms; Tyrosine

Previously, we proposed a novel mouse model for colitis-related colon carcinogenesis using azoxymethane (AOM) and dextran sodium sulfate (DSS) (Cancer Sci 2003; 94: 965-73). In the current study, sequential analysis of pathological alterations during carcinogenesis in our model was conducted to establish the influence of inflammation caused by DSS on colon carcinogenesis in this model. Male ICR mice were given a single intraperitoneal injection of AOM (10 mg/kg body weight) and given 2% (w/v) DSS in the drinking water for 7 days, starting 1 week after the AOM injection. They were sequentially sacrificed at weeks 2, 3, 4, 5, 6, 9, 12, and 14 for histopathological and immunohistochemical examinations. Colonic adenomas were found in 2 (40% incidence and 0.40 +/- 0.49 multiplicity) of 5 mice at week 3 and colon carcinomas developed in 2 (40% incidence and 2.00 +/- 3.52 multiplicity) of 5 mice at week 4. Their incidence gradually increased with time and reached 100% (6.20 +/- 2.48 multiplicity) at week 6. At week 14, the multiplicity of adenocarcinoma was 9.75 +/- 2.49 (100% incidence). In addition, colonic dysplasia was noted at all time-points. The scores of colonic inflammation and nitrotyrosine immunohistochemistry were extremely high at early time-points and were well correlated. Our results suggest that combined treatment of mice with AOM and DSS generates neoplasms in the colonic mucosa via dysplastic lesions induced by nitrosative stress.

Topics: Adenocarcinoma; Animals; Azoxymethane; Carcinogens; Colitis; Colon; Colonic Neoplasms; Dextran Sulfate; Immunoenzyme Techniques; Incidence; Injections, Intraperitoneal; Intestinal Mucosa; Male; Mice; Mice, Inbred ICR; Precancerous Conditions; Tyrosine

Human liver cancers have been associated mainly with chronic inflammations such as viral hepatitis B or C. This suggests that prolonged cell damage by chronic inflammation is critical in cancer development. Overproduction of nitric oxide (NO.) and its derivative (NOx, peroxynitrite) has been implicated as a cause of tissue damage by inflammation, thus contributing to tumor promotion. We have demonstrated the expression of the inducible isoform of nitric oxide synthase (iNOS) and 3-nitrotyrosine, a marker of peroxynitrite formation, by immunohistochemistry in preneoplastic and neoplastic rat liver tissues induced by continuous infusion of N-nitrosodiethylamine with mini-pumps. The preneoplastic lesions were characterized by proliferation of phenotypically altered hepatic foci (PAHF), dysplastic hepatocytes and oval cells. Histologically, the tumors were hepatocellular carcinomas (HCCs) of trabecular, (pseudo)glandular and solid types with or without cholangiocellular involvement. iNOS was located mainly in oval cells, capillary endothelial and muscular cells, epithelia of cholangiomas and glandular HCCs. 3-Nitrotyrosine was observed in the cytoplasms of PAHF and dysplastic hepatocytes in preneoplasias and in the cytoplasms of some living or apoptotic HCC cells, connective tissues, proteinaceous fluids, sinusoidal endothelia of tumorous hepatocytes and cholangiomas in tumors. From these observations, we suggest that: (i) chronic tissue damage by chemical carcinogens may act to induce iNOS and peroxynitrite formation; (ii) oval cells play a key role in development and/or growth of tumor tissues by producing NO. via iNOS, which may also cause tissue damage by peroxynitrite; (iii) iNOS can be considered as a phenotypic marker in cells of oval cell lineage and neovascularized capillaries in tumor tissues.

Topics: Adenoma, Bile Duct; Animals; Apoptosis; Carcinoma, Hepatocellular; Diethylnitrosamine; Immunohistochemistry; Liver; Liver Neoplasms; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Precancerous Conditions; Rats; Rats, Inbred F344; Rats, Sprague-Dawley; Tyrosine