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Introduction: The known connections between the terms 'sartans' and 'melanoma' has grown recently in the clinical field, suggesting that the relationship between these concepts is very likely to be significant, rather than hypothetical or unfeasible. This is because: 1) the presence of angiotensin receptors in melanoma tissue, melanocytes and skin is a known fact; 2) the influence of sartans on the processes of melanogenesis has already been presented in recent published scientific papers; 3) key in vitro studies have shown that angiotensin receptor blockers (sartans) could potentiate carcinogenesis in the direction of melanoma and metastases; and 4) clinical examples of the occurrence of melanoma after starting therapy with sartans have become numerous and difficult to ignore.Areas covered: We report the first case of occult melanoma in an 87-year-old Bulgarian patient, this manifested in the form of a solitary metastasis on the left arm, which occurred after long-term therapy with telmisartan.Expert opinion: The fact that nitrosamines have a proven carcinogenic effect and are the cause of heterogeneous neoplasms shows that they have the potential to be possible melanoma triggers. The multifactorial pathogenesis of melanoma could certainly be clarified after the 'crystallization' of this currently serious issue.
Assuntos
Melanoma/induzido quimicamente , Neoplasias Cutâneas/induzido quimicamente , Telmisartan/efeitos adversos , Idoso de 80 Anos ou mais , Bloqueadores do Receptor Tipo 1 de Angiotensina II/administração & dosagem , Bloqueadores do Receptor Tipo 1 de Angiotensina II/efeitos adversos , Humanos , Melanoma/diagnóstico , Melanoma/patologia , Nitrosaminas/administração & dosagem , Nitrosaminas/efeitos adversos , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/patologia , Telmisartan/administração & dosagemRESUMO
Tobacco smoke is a complex mixture of chemicals, many of which are toxic and carcinogenic. Hazard assessments of tobacco smoke exposure have predominantly focused on either single chemical exposures or the more complex mixtures of tobacco smoke or its fractions. There are fewer studies exploring interactions between specific tobacco smoke chemicals. Aldehydes such as formaldehyde and acetaldehyde were hypothesized to enhance the carcinogenic properties of the human carcinogen, 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK) through a variety of mechanisms. This hypothesis was tested in the established NNK-induced A/J mouse lung tumor model. A/J mice were exposed to NNK (intraperitoneal injection, 0, 2.5, or 7.5 µmol in saline) in the presence or absence of acetaldehyde (0 or 360 ppmv) or formaldehyde (0 or 17 ppmv) for 3 h in a nose-only inhalation chamber, and lung tumors were counted 16 weeks later. Neither aldehyde by itself induced lung tumors. However, mice receiving both NNK and acetaldehyde or formaldehyde had more adenomas with dysplasia or progression than those receiving only NNK, suggesting that aldehydes may increase the severity of NNK-induced lung adenomas. The aldehyde coexposure did not affect the levels of NNK-derived DNA adduct levels. Similar studies tested the ability of a 3 h nose-only carbon dioxide (0, 5, 10, or 15%) coexposure to influence lung adenoma formation by NNK. While carbon dioxide alone was not carcinogenic, it significantly increased the number of NNK-derived lung adenomas without affecting NNK-derived DNA damage. These studies indicate that the chemicals in tobacco smoke work together to form a potent lung carcinogenic mixture.
Assuntos
Aldeídos/toxicidade , Dióxido de Carbono/toxicidade , Carcinógenos/toxicidade , Neoplasias Pulmonares/induzido quimicamente , Nitrosaminas/toxicidade , Administração por Inalação , Aldeídos/administração & dosagem , Aldeídos/química , Animais , Dióxido de Carbono/administração & dosagem , Dióxido de Carbono/química , Carcinógenos/administração & dosagem , Carcinógenos/química , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Neoplasias Pulmonares/metabolismo , Camundongos , Estrutura Molecular , Nitrosaminas/administração & dosagem , Nicotiana/químicaAssuntos
Metformina/efeitos adversos , Neoplasias/induzido quimicamente , Nitrosaminas/efeitos adversos , Padrões de Prática Médica , Preparações de Ação Retardada/efeitos adversos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Indústria Farmacêutica/ética , Indústria Farmacêutica/legislação & jurisprudência , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/complicações , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/psicologia , Humanos , Hipoglicemiantes/uso terapêutico , Metformina/administração & dosagem , Nitrosaminas/administração & dosagem , Segurança do Paciente/legislação & jurisprudência , Relações Médico-Paciente , Padrões de Prática Médica/ética , Padrões de Prática Médica/legislação & jurisprudência , Reino Unido , Estados UnidosRESUMO
Metabolic activation of the carcinogenic tobacco-specific nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) results in formation of reactive electrophiles that modify DNA to produce a variety of products including methyl, 4-(3-pyridyl)-4-oxobutyl (POB)-, and 4-(3-pyridyl)-4-hydroxybutyl adducts. Among these are adducts such as 7-POB-deoxyguanosine (N7POBdG) which can lead to apurinic/apyrimidinic (AP) sites by facile hydrolysis of the base-deoxyribonucleoside bond. In this study, we used a recently developed highly sensitive mass spectrometric method to quantitate AP sites by derivatization with O-(pyridin-3-yl-methyl)hydroxylamine (PMOA) (detection limit, 2 AP sites per 108 nucleotides). AP sites were quantified in DNA isolated from tissues of rats treated with NNN and NNK and from human lung tissue and leukocytes of cigarette smokers and nonsmokers. Rats treated with 5 or 21 mg/kg bw NNK for 4 days by s.c. injection had 2-6 and 2-17 times more AP sites than controls in liver and lung DNA (p < 0.05). Increases in AP sites were also found in liver DNA of rats exposed for 10 and 30 weeks (p < 0.05) but not for 50 and 70 weeks to 5 ppm of NNK in their drinking water. Levels of N7POBG were significantly correlated with AP sites in rats treated with NNK. In rats treated with 14 ppm (S)-NNN in their drinking water for 10 weeks, increased AP site formation compared to controls was observed in oral and nasal respiratory mucosa DNA (p < 0.05). No significant increase in AP sites was found in human lung and leukocyte DNA of cigarette smokers compared to nonsmokers, although AP sites in leukocyte DNA were significantly correlated with urinary levels of the NNK metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). This is the first study to use mass spectrometry based methods to examine AP site formation by carcinogenic tobacco-specific nitrosamines in laboratory animals and to evaluate AP sites in DNA of smokers and nonsmokers.
Assuntos
DNA/efeitos dos fármacos , Nicotiana/química , Nitrosaminas/análise , Produtos do Tabaco/análise , Animais , Dano ao DNA , Humanos , Leucócitos/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Masculino , Espectrometria de Massas , Nitrosaminas/administração & dosagem , Nitrosaminas/farmacologia , não Fumantes , Ratos , Ratos Endogâmicos F344 , FumantesRESUMO
Lung cancer remains the leading cause of cancer-related deaths worldwide. In order to understand lung cancer biology and evaluate novel therapeutic strategies, preclinical mouse models have been developed that mimic early and advanced-stage lung cancer. Among autochthonous models, carcinogen-induced systems are valuable preclinical tools since tobacco smoking remains the number one risk factor for lung tumor development. Among the several thousand chemicals within cigarette smoke, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent carcinogen with tumorigenic effects described in both mice and humans. Herein, we describe the methodology for inducing lung tumors in mice using the tobacco carcinogen NNK and subsequent lung fixation for quantitative assessment of tumor development and analysis of oncogenic mutations in tumors.
Assuntos
Carcinógenos/toxicidade , Modelos Animais de Doenças , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Pulmão/patologia , Pulmão/cirurgia , Nitrosaminas/toxicidade , Animais , DNA/genética , DNA/isolamento & purificação , Análise Mutacional de DNA , Imuno-Histoquímica , Pulmão/citologia , Neoplasias Pulmonares/induzido quimicamente , Camundongos , Camundongos Endogâmicos , Nitrosaminas/administração & dosagem , Nicotiana/toxicidade , Fluxo de TrabalhoRESUMO
INTRODUCTION: This 8-week multisite, randomized controlled trial of snus examined the differential effects of instructions on (1) snus use, (2) smoking and smoking-related measures, and (3) exposure to tobacco-related constituents. METHOD: US adult daily cigarette smokers (n = 150; 43.3% female; Medianage = 43.5) were recruited from Minneapolis, Minnesota; Columbus and Coshocton, Ohio; and Buffalo, New York. Following a 1-week sampling phase of snus, participants who used at least 7 pouches were randomized to either (1) partial substitution (PS; "use snus as you like with your cigarettes"), (2) complete substitution (CS; "avoid cigarettes"), or (3) usual brand cigarettes (UB). Analyses included between-group analyses (eg, PS vs. CS) using Wilcoxon rank sum test of cigarettes per day and snus pouches per day, and a linear mixed model (biomarkers). RESULTS: Compared to the PS and UB groups, smokers assigned to CS reported greater reductions in cigarettes per day (ps < .001), using more snus pouches per day (p = .02), and more smoke-free days (CS median = 14.5, PS and UB medians = 0, p < .001). In addition, results demonstrated reductions in carbon monoxide (p < .001), total nicotine equivalents (p = .02), and four out of five measured volatile organic compounds (ps < .01) over time among the CS group. Exposure to N'-nitrosonornicotine increased by trial end only among the PS group (p < .04). Phenanthrene tetraol increased among all groups by trial end (p = .02) with no difference between groups. CONCLUSIONS: Instructions to completely switch from cigarettes to snus resulted in the greatest reduction in cigarettes and exposure to harmful constituents. IMPLICATIONS: Directly instructing smokers to switch completely to snus, rather than using ad libitum (with no instructions to avoid cigarettes), is necessary for reductions in smoking and subsequent exposure to harmful constituents.
Assuntos
Biomarcadores/metabolismo , Fumar/epidemiologia , Fumar/psicologia , Tabagismo/epidemiologia , Tabagismo/metabolismo , Tabaco sem Fumaça/estatística & dados numéricos , Adolescente , Adulto , Monóxido de Carbono/análise , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Minnesota/epidemiologia , New York/epidemiologia , Nitrosaminas/administração & dosagem , Fumar/metabolismo , Abandono do Hábito de Fumar/métodos , Tabagismo/diagnóstico , Adulto JovemRESUMO
Esophageal cancer is prevalent in Cixian, China, but the etiology of this disease remains largely unknown. Therefore, we explored this by conducting a DNA adductome analysis. Both tumorous and nontumorous tissues were collected from patients who underwent surgical procedures at Cixian Cancer Hospital and the Fourth Hospital of Hebei Medical University, which is in a low-incidence area. N2-(3,4,5,6-Tetrahydro-2H-pyran-2-yl)deoxyguanosine (THP-dG) was the major adduct detected in samples from esophageal cancer patients in Cixian. The precursor of THP-dG, N-nitrosopiperidine (NPIP), exhibited a strong mutagenic activity under metabolic activation in the Ames test and a significant dose-dependent increase in mutation frequency during an in vivo mutagenicity test with guanine phosphoribosyltransferase (gpt) delta rats. The NPIP-induced mutation was dominated by A:T to C:G transversions, followed by G:C to A:T and A:T to G:C transitions, in the liver and esophagus of animal samples. A similar mutational pattern was observed in the mutational signature of esophageal cancer patients that demonstrated weak correlation with THP-dG levels. These findings suggested that NPIP exposure is partly involved in the development of esophageal cancer in Cixian residents.
Assuntos
Adutos de DNA/análise , Neoplasias Esofágicas/diagnóstico , Nitrosaminas/análise , Administração Oral , Adulto , Idoso , Animais , China , Cromatografia Líquida , DNA/química , DNA/isolamento & purificação , Neoplasias Esofágicas/induzido quimicamente , Neoplasias Esofágicas/etiologia , Feminino , Humanos , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Nitrosaminas/administração & dosagem , Ratos , Ratos Endogâmicos F344RESUMO
The tobacco-specific carcinogens N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) require metabolic activation to exert their carcinogenicity. NNN and NNK are metabolized to the same reactive diazonium ions, which alkylate DNA forming pyridyloxobutyl (POB) DNA base and phosphate adducts. We have characterized the formation of both POB DNA base and phosphate adducts in NNK-treated rats and the formation of POB DNA base adducts in NNN-treated rats. However, POB DNA phosphate adducts in NNN-treated rats are still uncharacterized. In this study, we quantified the levels of POB DNA phosphate adducts in tissues of rats chronically treated with ( S)-NNN or ( R)-NNN for 10, 30, 50, and 70 weeks during a carcinogenicity study. The highest amounts of POB DNA phosphate adducts were observed in the esophagus of the ( S)-NNN-treated rats, with a maximum level of 5400 ± 317 fmol/mg DNA at 50 weeks. The abundance of POB DNA phosphate adducts in the esophagus was consistent with the results of the carcinogenicity study showing that the esophagus was the primary site of tumor formation from treatment with ( S)-NNN. Compared to the ( R)-NNN group, the levels of POB DNA phosphate adducts were higher in the oral mucosa, esophagus, and liver, while lower in the nasal mucosa of the ( S)-NNN-treated rats. Among 10 combinations of all isomers of POB DNA phosphate adducts, Ap(POB)C and combinations with thymidine predominated across all the rat tissues examined. In the primary target tissue, esophageal mucosa, Ap(POB)C accounted for â¼20% of total phosphate adducts in the ( S)-NNN treatment group throughout the 70 weeks, with levels ranging from 780 ± 194 to 1010 ± 700 fmol/mg DNA. The results of this study showed that POB DNA phosphate adducts were present in high levels and persisted in target tissues of rats chronically treated with ( S)- or ( R)-NNN. These results improve our understanding of DNA damage during NNN-induced carcinogenesis. The predominant POB DNA phosphate isomers observed, such as Ap(POB)C, may serve as biomarkers for monitoring chronic exposure of tobacco-specific nitrosamines in humans.
Assuntos
Adutos de DNA/análise , Nitrosaminas/metabolismo , Fosfatos/análise , Piridinas/análise , Animais , Adutos de DNA/metabolismo , Hidrólise , Masculino , Espectrometria de Massas , Estrutura Molecular , Nitrosaminas/administração & dosagem , Nitrosaminas/química , Fosfatos/metabolismo , Piridinas/metabolismo , Ratos , Ratos Endogâmicos F344 , EstereoisomerismoRESUMO
The tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), is a potent lung carcinogen that exerts its carcinogenic effects upon metabolic activation. The identification and quantitation of NNK metabolites could identify potential biomarkers of bioactivation and detoxification of this potent carcinogen and may be used to predict lung cancer susceptibility among smokers. Here, we used in vivo isotope-labeling and high-resolution-mass-spectrometry-based methods for the comprehensive profiling of all known and unknown NNK metabolites. The sample-enrichment, LC-MS, and data-analysis workflow, including a custom script for automated d0- d4- m/ z-pair-peak detection, enabled unbiased identification of numerous NNK metabolites. The structures of the metabolites were confirmed using targeted LC-MS2 with retention-time ( tR) and MS2-fragmentation comparisons to those of standards when possible. Eleven known metabolites and unchanged NNK were identified simultaneously. More importantly, our workflow revealed novel NNK metabolites, including 1,3-Diol (13), α-OH-methyl-NNAL-Gluc (14), nitro-NK- N-oxide (15), nitro-NAL- N-oxide (16), γ-OH NNAL (17), and three N-acetylcysteine (NAC) metabolites (18a-c). We measured the differences in the relative distributions of a panel of nitroso-containing NNK-specific metabolites in rats before and after phenobarbital (PB) treatment, and this served as a demonstration of a general strategy for the detection of metabolic differences in animal and cell systems. Lastly, we generated a d4-labeled NNK-metabolite mixture to be used as internal standards ( d4-rat urine) for the relative quantitation of NNK metabolites in humans, and this new strategy will be used to assess carcinogen exposure and ultimately to evaluate lung-cancer risk and susceptibility in smokers.
Assuntos
Carcinógenos/análise , Carcinógenos/metabolismo , Metabolômica , Animais , Carcinógenos/administração & dosagem , Cromatografia Líquida , Injeções Intraperitoneais , Marcação por Isótopo , Espectrometria de Massas , Estrutura Molecular , Nitrosaminas/administração & dosagem , Nitrosaminas/metabolismo , Nitrosaminas/urina , Ratos , Ratos Endogâmicos F344RESUMO
Smoking leads to the occurrence and development of a variety of diseases. Most importantly, it is an independent risk factor of cardiovascular atherosclerosis. In recent years, electronic cigarettes have become a popular alternative to traditional cigarettes, since modern micro-electronic techniques provide the possibility of simulating the process of traditional smoking. Additionally, it is convenient and fashionable. Nevertheless, comments about the safety of electronic cigarettes remain controversial. Although the research about electronic cigarettes increased exponentially, there has been no systematic study of its safety. The aim of the current study is to review the literature reports about the safety of electronic cigarettes, and to understand their hazards and disadvantages. It was found that most of the current research about electronic cigarettes comprises short-term and in vitro studies. There are few reports of in vivo and long-term studies. Notably, the level of harmful components such as volatile organic compounds, tobacco-specific nitrosamines and heavy metals in electronic cigarettes are even higher than in traditional cigarettes. Therefore, the harm of electronic cigarettes should not be underestimated. In conclusion, the question of whether electronic cigarettes are a safe and sufficient substitute for traditional smoking needs further investigation.
Assuntos
Aterosclerose/etiologia , Sistemas Eletrônicos de Liberação de Nicotina , Nicotina/administração & dosagem , Nitrosaminas/administração & dosagem , Fumar/efeitos adversos , Compostos Orgânicos Voláteis/administração & dosagem , Aterosclerose/fisiopatologia , Humanos , Nicotina/efeitos adversos , Nitrosaminas/efeitos adversos , Medição de Risco , Fatores de Risco , Fumar/epidemiologia , Fumar/fisiopatologia , Abandono do Hábito de Fumar/métodos , Compostos Orgânicos Voláteis/efeitos adversosRESUMO
The tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is metabolically converted to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in a reaction which is both stereoselective and reversible. NNAL is also a lung carcinogen, with both (R)-NNAL and (S)-NNAL inducing a high incidence of lung tumours in rats. Both NNAL and NNK undergo metabolic activation to intermediates which react with DNA to form pyridylhydroxybutyl and pyridyloxobutyl DNA adducts, respectively. DNA adduct formation by NNAL and NNK is an important step in their mechanisms of carcinogenesis. In this study, we quantified both pyridylhydroxybutyl and pyridyloxobutyl DNA phosphate adducts in the lung of rats treated with 5 ppm of (R)-NNAL or (S)-NNAL in drinking water for 10, 30, 50 and 70 weeks. In (R)-NNAL-treated rats, the pyridylhydroxybutyl and pyridyloxobutyl phosphate adducts were 4530-6920 fmol/mg DNA and 46-175 fmol/mg DNA, accounting for 45-51% and 0.3-1% of the total measured DNA phosphate and base adducts, respectively. In (S)-NNAL-treated rats, the two types of phosphate adducts were 3480-4180 fmol/mg DNA and 1180-4650 fmol/mg DNA, accounting for 30-36% and 11-38% of the total adducts, respectively. Distinct patterns of adduct formation were observed, with higher levels of NNAL-derived pyridylhydroxybutyl phosphate adducts and lower levels of NNK-derived pyridyloxobutyl phosphate adducts in the (R)-NNAL treatment group than the (S)-NNAL group. The persistence and increase over time of certain pyridylhydroxybutyl phosphate adducts over the course of the study suggest that these adducts could be useful biomarkers of chronic exposure to NNAL and NNK. The results of this study provide important new information regarding DNA damage by NNAL and NNK, and contribute to understanding mechanisms of tobacco-related carcinogenesis.
Assuntos
Adutos de DNA/metabolismo , DNA/metabolismo , Nicotiana/química , Nitrosaminas/administração & dosagem , Nitrosaminas/química , Fosfatos/metabolismo , Piridinas/química , Animais , Adutos de DNA/química , Masculino , Fosfatos/química , Ratos Endogâmicos F344 , EstereoisomerismoRESUMO
The role of deficiency of oxoguanine glycosylase 1 (Ogg1) Mmh homolog, a repair enzyme of the 8-hydroxy-2'-deoxyguanosine (8-OHdG) residue in DNA, was investigated using the multiorgan carcinogenesis bioassay in mice. A total of 80 male and female six-week-old mice of C57BL/6J background carrying a mutant Mmh allele of the Mmh/Ogg1 gene (Ogg1-/-) and wild type (Ogg1+/+) mice were administered N-diethylnitrosamine (DEN), N-methyl-N-nitrosourea (MNU), N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN), N-bis (2-hydroxypropyl) nitrosamine (DHPN) and 1,2-dimethylhydrazine dihydrochloride (DMH) (DMBDD) to induce carcinogenesis in multiple organs, and observed up to 34 weeks. Significant increase of lung adenocarcinomas incidence was observed in DMBDD-treated Ogg1-/- male mice, but not in DMBDD-administered Ogg1+/+ animals. Furthermore, incidences of lung adenomas were significantly elevated in both Ogg1-/- males and females as compared with respective Ogg1-/- control and DMBDD-treated Ogg1+/+ groups. Incidence of total liver tumors (hepatocellular adenomas, hemangiomas and hemangiosarcomas) was significantly higher in the DMBDD-administered Ogg1-/- males and females. In addition, in DMBDD-treated male Ogg1-/- mice, incidences of colon adenomas and total colon tumors showed a trend and a significant increase, respectively, along with significant rise in incidence of simple hyperplasia of the urinary bladder, and a trend to increase for renal tubules hyperplasia in the kidney. Furthermore, incidence of squamous cell hyperplasia in the forestomach of DMBDD-treated Ogg1-/- male mice was significantly higher than that of Ogg1+/+ males. Incidence of small intestine adenomas in DMBDD Ogg1-/- groups showed a trend for increase, as compared to the wild type mice. The current results demonstrated increased susceptibility of Ogg1 mutant mice to the multiorgan carcinogenesis induced by DMBDD. The present bioassay could become a useful tool to examine the influence of various targets on mouse carcinogenesis.
Assuntos
Carcinogênese/genética , Carcinógenos/toxicidade , DNA Glicosilases/genética , Mutação , 1,2-Dimetilidrazina/administração & dosagem , 1,2-Dimetilidrazina/toxicidade , Adenocarcinoma/induzido quimicamente , Adenocarcinoma/genética , Animais , Butilidroxibutilnitrosamina/administração & dosagem , Butilidroxibutilnitrosamina/toxicidade , Carcinogênese/induzido quimicamente , Carcinógenos/administração & dosagem , Carcinoma Hepatocelular/induzido quimicamente , Carcinoma Hepatocelular/genética , Dietilnitrosamina/administração & dosagem , Dietilnitrosamina/toxicidade , Feminino , Neoplasias Hepáticas/induzido quimicamente , Neoplasias Hepáticas/genética , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/genética , Masculino , Metilnitrosoureia/administração & dosagem , Metilnitrosoureia/toxicidade , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nitrosaminas/administração & dosagem , Nitrosaminas/toxicidadeRESUMO
4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent and prevalent nitrosamine procarcinogen found in cigarette smoke. The aim of this work is to study alterations in peroxiredoxin (Prx) expression induced by NNK during carcinogenesis. Characterization of Prx genes from hamster was performed using bioinformatics. V79 cells were induced with different concentrations of NNK (0.1-0.4 mg/mL), and the expression levels of six Prx genes (Prx1-Prx6) were measured by qRT-PCR 24 h following NNK treatment. Prx gene expression was induced by NNK stress, and the highest transcription levels were induced by over 20.42-fold relative to that of the control. NNK induced alterations in Prx expression over the course of lung cancer, which means Prxs may play important roles in ROS detoxification under NNK stress and their functions are complementary.
Assuntos
Carcinógenos/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Nitrosaminas/toxicidade , Peroxirredoxinas/metabolismo , Animais , Carcinógenos/administração & dosagem , Linhagem Celular , Sobrevivência Celular , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Nitrosaminas/administração & dosagem , Peroxirredoxinas/genéticaRESUMO
Recently, we have shown that (S)-N'-Nitrosonornicotine [(S)-NNN], the major form of NNN in tobacco products, is a potent oral cavity and esophageal carcinogen in rats. To determine the early molecular alterations induced by (S)-NNN in the oral and esophageal mucosa, we administered the carcinogen to rats in the drinking water for 10 wk and global gene expression alterations were analyzed by RNA sequencing. At a false discovery rate P-value < 0.05 and fold-change ≥2, we found alterations in the level of 39 genes in the oral cavity and 69 genes in the esophagus. Validation of RNA sequencing results by qRT-PCR assays revealed a high cross-platform concordance. The most significant impact of exposure to (S)-NNN was alteration of genes involved in immune regulation (Aire, Ctla4, and CD80), inflammation (Ephx2 and Inpp5d) and cancer (Cdkn2a, Dhh, Fetub B, Inpp5d, Ly6E, Nr1d1, and Wnt6). Consistent with the findings in rat tissues, most of the genes were deregulated, albeit to different degrees, in immortalized oral keratinocytes treated with (S)-NNN and in non-treated premalignant oral cells and malignant oral and head and neck squamous cells. Furthermore, interrogation of TCGA data sets showed that genes deregulated by (S)-NNN in rat tissues (Fetub, Ly6e, Nr1d1, Cacna1c, Cd80, and Dgkg) are also altered in esophageal and head and neck tumors. Overall, our findings provide novel insights into early molecular changes induced by (S)-NNN and, therefore, could contribute to the development of biomarkers for the early detection and prevention of (S)-NNN-associated oral and esophageal cancers. © 2016 Wiley Periodicals, Inc.
Assuntos
Carcinogênese/genética , Carcinógenos/toxicidade , Neoplasias Esofágicas/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Bucais/genética , Nitrosaminas/toxicidade , Transcriptoma , Animais , Carcinogênese/induzido quimicamente , Carcinógenos/administração & dosagem , Neoplasias Esofágicas/induzido quimicamente , Esôfago/efeitos dos fármacos , Esôfago/metabolismo , Humanos , Masculino , Boca/efeitos dos fármacos , Boca/metabolismo , Neoplasias Bucais/induzido quimicamente , Nitrosaminas/administração & dosagem , Ratos Endogâmicos F344RESUMO
(S)-N'-Nitrosonornicotine [(S)-NNN] and racemic NNN are powerful oral and esophageal carcinogens in the F344 rat, whereas (R)-NNN has only weak activity. Tumor formation in these tissues of rats treated with racemic NNN was far greater than the sum of the activities of the individual enantiomers. We hypothesized that metabolites of (R)-NNN enhanced levels of DNA adducts produced by (S)-NNN. A test of that hypothesis necessitated the development of a novel liquid chromatography-nanoelectrospray ionization-high resolution tandem mass spectrometry method for the analysis of O(6)-[4-(3-pyridyl)-4-oxobut-1-yl]-2'-deoxyguanosine (O(6)-POB-dGuo), a highly mutagenic DNA adduct not previously quantified in rats treated with NNN. The new method, with a limit of detection of 6.5 amol for diluted standard and 100 amol for DNA samples, was applied in this study. Groups of nine F344 rats were treated with doses as follows: 7 ppm (R)-NNN, 7 ppm (S)-NNN, and 14 ppm racemic NNN; 14 ppm (R)-NNN, 14 ppm (S)-NNN, and 28 ppm racemic NNN; or 28 ppm (R)-NNN, 28 ppm (S)-NNN, and 56 ppm racemic NNN for 5 weeks, and tissues were analyzed for DNA adducts. We found statistically significant, but modest, synergistic enhancement of levels of O(6)-POB-dGuo in the esophagus but not the oral cavity of rats treated with racemic NNN (low and median doses only) compared to the sum of the amounts formed in these tissues of rats treated with (S)-NNN or (R)-NNN. There was no synergy in the formation of other POB-DNA adducts of NNN in oral cavity and esophagus, nor was there any evidence for synergy in nasal respiratory and olfactory epithelium, lung, or liver. Our results provide the first quantitation of O(6)-POB-dGuo in DNA from tissues of rats treated with NNN and evidence for synergy in DNA adduct formation as one possible mechanism by which (R)-NNN enhances the carcinogenicity of (S)-NNN in rats.
Assuntos
Adutos de DNA/análise , Adutos de DNA/química , Desoxiguanosina/análogos & derivados , Nitrosaminas/química , Nitrosaminas/farmacocinética , Animais , Desoxiguanosina/química , Masculino , Estrutura Molecular , Nitrosaminas/administração & dosagem , Nitrosaminas/farmacologia , Ratos , Ratos Endogâmicos F344 , Distribuição TecidualRESUMO
OBJECTIVES: Animal evidence shows that N-nitrosamines and similar xenobiotic compounds are pancreatic carcinogens. We aimed to determine whether occupational exposure to N-nitrosamines or to pesticides increases risk of pancreatic cancer development. METHODS: Participants (504 cases, 643 controls) in a population-based case-control study (The Queensland Pancreatic Cancer Study) provided data on demographic, medical and lifestyle factors and lifetime job histories. Specific questions were asked regarding work in rubber and leather industries, metalworking jobs and occupational or direct use of pesticides on animals or crops. An occupational hygienist reviewed this information (blind to case status) to assess likelihood of exposure to N-nitrosamines and pesticides, and estimated level and frequency of such exposures. RESULTS: No associations were found for risk of pancreatic cancer and occupational exposure to N-nitrosamines (OR=0.85, 95% CI 0.51 to 1.42) and no associations were seen with level or frequency of exposure. No associations were observed for ever exposure to pesticides in general (OR=0.90, 95% CI 0.61 to 1.33) or to any of the pesticide subgroups. Stratification by history of cigarette smoking did not change these results. CONCLUSIONS: This comprehensive analysis of a large case-control study does not support an association between occupational exposure to N-nitrosamines or pesticide use and risk of pancreatic cancer.
Assuntos
Nitrosaminas/administração & dosagem , Exposição Ocupacional , Ocupações , Neoplasias Pancreáticas/etiologia , Praguicidas , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinógenos , Estudos de Casos e Controles , Feminino , Humanos , Indústrias , Masculino , Pessoa de Meia-Idade , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/análise , Razão de Chances , Praguicidas/efeitos adversos , Queensland , Risco , Medição de Risco , Fatores de Risco , FumarRESUMO
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a multiple-site, multiple-species carcinogen that induces cancer in multiple organs. The molecular mechanisms underlying TCDD-induced lung tumorigenesis remain unclear. In the present study, a two-stage lung tumorigenesis model was established by administrating a single low dose of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) combined with TCDD to female A/J mice. The results indicated that TCDD combined with low-dose NNK has a significant tumor-promoting effect compared with TCDD or low-dose NNK alone. Resistance to apoptosis is a hallmark of cancer and is thought to be one of the tumor-promoting mechanisms regulated by TCDD. We performed an additional series of experiments in the normal human bronchial epithelial cell line Beas2B cells, in which TCDD was combined with the apoptosis inducer staurosporine. Our in vitro results confirmed that TCDD could rescue cells from apoptosis induced by staurosporine. The inhibition of apoptosis is likely mediated by the activation of the Akt and ERK1/2 pathways, as determined by the effectiveness of pathway-specific inhibitors in abrogating the anti-apoptotic activity of TCDD. In conclusion, we demonstrated that TCDD promoted NNK-induced lung tumorigenesis and revealed that TCDD inhibits staurosporine-induced apoptosis, at least in part, through the Akt and ERK1/2 signaling pathways.
Assuntos
Carcinógenos Ambientais/toxicidade , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Nitrosaminas/administração & dosagem , Dibenzodioxinas Policloradas/toxicidade , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Proliferação de Células , Cocarcinogênese , Sinergismo Farmacológico , Inibidores Enzimáticos/farmacologia , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/metabolismo , Camundongos , Nitrosaminas/toxicidade , Estaurosporina/farmacologiaRESUMO
Emission and accumulation of carbon dioxide (CO2) in the atmosphere exert an environmental and climate change challenge. An attempt to deal with this challenge is made at Mongstad by application of amines for CO2 capture and storage (CO2 capture Mongstad (CCM) project). As part of the CO2 capture process, nitrosamines and nitramines may be emitted. Toxicological testing of nitrosamines and nitramines indicate a genotoxic potential of these substances. Here we present a risk characterization and assessment for five nitrosamines (N-Nitrosodi-methylamine (NDMA) N-Nitrosodi-ethylamine (NDEA), N-Nitroso-morpholine (NNM), N-Nitroso-piperidine (NPIP), and Dinitroso-piperazine (DNP)) and two nitramines (N-Methyl-nitramine (NTMA), Dimethyl-nitramine (NDTMA)), which are potentially emitted from the CO2 capture plant (CCP). Human health risk assessment of genotoxic non-threshold substances is a heavily debated topic, and no consensus methodology exists internationally. Extrapolation modeling from high-dose animal exposures to low-dose human exposures can be crucial for the final risk calculation. In the work presented here, different extrapolation models are discussed, and suggestions on applications are given. Then, preferred methods for calculating derived minimal effect level (DMEL) are presented with the selected nitrosamines and nitramines.
Assuntos
Compostos de Anilina/toxicidade , Dióxido de Carbono/isolamento & purificação , Nitrobenzenos/toxicidade , Nitrosaminas/toxicidade , Compostos de Anilina/administração & dosagem , Animais , Mudança Climática , Exposição Ambiental , Humanos , Testes de Mutagenicidade , Mutagênicos/administração & dosagem , Mutagênicos/toxicidade , Nitrobenzenos/administração & dosagem , Nitrosaminas/administração & dosagem , Medição de RiscoRESUMO
The tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), induces lung tumors in rodents and has been suggested as a causative factor in human lung cancer. NNK is activated by α-hydroxylation at either the methyl or methylene carbon adjacent to the N-nitroso group to yield unstable intermediates that spontaneously decompose to produce alkylating agents. 4-(Hydroxymethylnitrosamino)-1-(3-pyridyl)-1-butanone (HO-methyl NNK) glucuronide, a glucuronide of the reactive intermediate of NNK has been identified. However, there are no available data concerning HO-methyl NNK glucuronide. In the present study, we investigated the tissue distribution of HO-methyl NNK glucuronide in control and phenobarbital (PB)-treated rats after intraperitoneal administration of NNK. In PB-treated rats, HO-methyl NNK glucuronide was detected in plasma, kidney, liver, lung, and pancreas. On the contrary, in the control rats, HO-methyl NNK glucuronide was detected only in plasma, kidney and liver at low concentrations compared with PB-treated rats. The results of cumulative urinary excretion of HO-methyl NNK glucuronide in Wistar and Gunn rats suggested that PB-inducible UDP-glucuronosyltransferase 2B isoforms mainly contribute to the formation of HO-methyl NNK glucuronide.
Assuntos
Glucuronídeos/metabolismo , Nitrosaminas/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Glucuronídeos/administração & dosagem , Glucuronídeos/química , Glucuronídeos/urina , Glucuronosiltransferase/fisiologia , Humanos , Injeções Intraperitoneais , Isoenzimas , Rim/metabolismo , Fígado/metabolismo , Masculino , Espectrometria de Massas , Antígenos de Histocompatibilidade Menor , Nitrosaminas/administração & dosagem , Nitrosaminas/química , Nitrosaminas/urina , Pâncreas/metabolismo , Fenobarbital , Ratos , Ratos Gunn , Ratos Wistar , Distribuição Tecidual , NicotianaRESUMO
The potential of the carcinogenic tobacco specific nitrosamine 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-1-butanone (NNK) to induce preneoplastic hepatocellular altered foci (HAF) was tested in the in ovo carcinogenicity assessment (IOCA) assay. Single doses of NNK over a dose range from 0.1 mg to 6 mg were injected into fertilized turkey eggs prior to incubation for 24 days. The livers were investigated by histological, histochemical and morphometric methods. Mortality was increased for eggs exposed to 6 mg. In this group, the whole livers were severely altered, showing pronounced changes of nucleus size and signs of cell death. At the dose of 2 mg various types of foci of altered hepatocytes (HAF) were observed. Basophilic cell foci of the solid or tubular type were most frequent. The NNK-induced HAF were very similar to the preneoplastic lesions that occur in the livers of mammals during hepatocarcinogenesis which are regarded as early indicators of carcinogenesis. The similarity to the HAF in rodents included histochemically detectable alterations like decreased activities of glucose-6-phosphatase, adenosine triphosphatase and glycogen phosphorylase. At doses of 1 mg or below, no HAF were detected. At all dose levels an increased occurrence of enlarged hepatocytes with enlarged nuclei and prominent nucleoli (karyomegalic hepatocytes) were observed. The increase in karyomegalic hepatocytes was also statistically significant at the low dose of 0.1 mg/kg NNK but the dose-effect curve for their induction was clearly non-linear. Induction of HAF and karyomegalic hepatocytes in ovo is a simple (one dose), rapid (24 days) and inexpensive (no animal purchase or housing) experimental approach for studies on chemically induced hepatocarcinogenesis.