DNA methylation changes associated with risk factors in tumors of the upper aerodigestive tract

Cancers of the upper aerodigestive tract (UADT) are common forms of malignancy associated with tobacco and alcohol exposures, although human papillomavirus and nutritional deficiency are also important risk factors. While somatically acquired DNA methylation changes have been associated with UADT cancers, what triggers these events and precise epigenetic targets are poorly understood. In this study, we applied quantitative profiling of DNA methylation states in a panel of cancer-associated genes to a case-control study of UADT cancers. Our analyses revealed a high frequency of aberrant hypermethylation of several genes, including MYOD1, CHRNA3 and MTHFR in UADT tumors, whereas CDKN2A was moderately hypermethylated. Among differentially methylated genes, we identified a new gene (the nicotinic acetycholine receptor gene) as target of aberrant hypermethylation in UADT cancers, suggesting that epigenetic deregulation of nicotinic acetycholine receptors in non-neuronal tissues may promote the development of UADT cancers. Importantly, we found that sex and age is strongly associated with the methylation states, whereas tobacco smoking and alcohol intake may also influence the methylation levels in specific genes. This study identifies aberrant DNA methylation patterns in UADT cancers and suggests a potential mechanism by which environmental factors may deregulate key cellular genes involved in tumor suppression and contribute to UADT cancers.IARCIARCla Ligue National (Francaise) Contre le Cancerla Ligue National (Francaise) Contre le CancerNational Institutes of Health/National Cancer Institute (NIH/NCI), United StatesNational Institutes of Health/National Cancer Institute (NIH/NCI), United StatesAssociation pour la Recherche sur le Cancer (ARC, France)l'Association pour la Recherche sur le Cancer (ARC), Francela Ligue Nationale (Francaise) Contre le Cancer (Comite SaoneetLoire), Francela Ligue Nationale (Francaise) Contre le Cancer (Comite Saone-et-Loire), FranceSwiss Bridge AwardSwiss Bridge Awar

Estudo comparativo da expressão imuno-histoquímica das proteínas Bcl-2, p53, caspase-3 e Ki-67 em hiperplasias fibrosas inflamatórias, queilites actínicas e carcinomas de células escamosas no lábio inferior

The natural ultraviolet radiation has been identified as the main aetiology of skin and lip injuries. Actinic keratosis in lip or actinic cheilitis, according to World Health Organization, as a premalignant lesion of the labial cancer, is presented, clinically, as the first signal that damages had been caused to the lip, most of the times, irreparable, being able to develop, in its great majority, in a squamous cell carcinoma. The action of the ultraviolet radiation in the development of malignant injuries occurs through its direct action in the cells leading to the damage in its DNA allowing that they continue the mitotic cycle with defective genes. The disordered relation between proliferation and cellular death can, mostly, predict the evolution and behavior of these injuries, besides supplying important information of the tumoral progression. The aim of this work was to evaluate, immunohistochemically, the inhibiting and proliferate expression of apoptosis and cellular proliferation proteins as, p53, mutate p53, Bcl-2, Ki-67 and caspase-3 in 20 cases of inflammatory fibrous hyperplasia, 20 of actinic cheilitis, being four with epithelium dysplasia and 20 of squamous cells carcinoma, all located in lower lip. The results had presented that the identification of proteins p53 (DO-7) and mutate p53 (PAb-240) had shown increasing with the progression of the injuries in the suprabasal region with diffuse distribution, as the Bcl-2 protein. Significant descriptive and quantitative difference were observed between proteins p53 (DO-7) and mutate p53 (PAb-240) in the three analyzed groups, showing that antibody DO-7 revealed a higher expression than the PAb-240. The antibody Ki-67 revealed high expression of the protein in the suprabasal region of all the groups although had not presented significant difference between them. The cases of cheilitis with and without epithelium dysplasia had disclosed a significant difference only for the markers mutate p53 (PAb-240) and Bcl-2. The xpression of these markers and p53 (DO-7) had shown higher in the cases without epithelium dysplasia. The expression detected in this study for these markers in all the lesions suggests that the loss of the regulation of apoptosis and the cellular proliferation also occurs in an initial phase of the development of the premalignant lesions included those where morphologically it is not possible to detect any alteration. These data show the importance of the immunomarkers study involved in bucal carcinogenesis for evaluation of the prognostic of premalignant and malignant lesions and the indication of more efficient therapeutical and preventive procedures.Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorA radiação ultravioleta natural tem sido identificada como o maior agente etiológico de lesões em pele e lábio. A ceratose actínica em lábio ou queilite actínica considerada, segundo a Organização Mundial de Saúde, como uma lesão prémaligna do câncer labial, apresenta-se, clinicamente, como o primeiro sinal de que danos foram causados ao lábio, muitas vezes irreparáveis, podendo evoluir, em sua grande maioria, para um carcinoma de células escamosas. A atuação da radiação ultravioleta no desenvolvimento de lesões malignas ocorre através da sua ação direta nas células levando ao dano em seu DNA permitindo que prossigam o ciclo mitótico com genes defeituosos. A relação desordenada entre proliferação e morte celular pode, muitas vezes, predizer a evolução e comportamento destas lesões, além de fornecer informações importantes da progressão tumoral. O objetivo deste trabalho foi avaliar através da técnica de imuno-histoquímica, a expressão de proteínas inibidoras e promotoras da apoptose e da proliferação celular como, p53, p53 mutado, Bcl-2, Ki-67 e caspase-3 em 20 casos de hiperplasias fibrosas inflamatórias, 20 de queilites actínicas, sendo quatro com displasia epitelial e 20 de carcinomas de células escamosas, todos localizados em lábio inferior. Os resultados mostraram que a identificação das proteínas p53 (DO-7) e p53 mutada (PAb-240) revelaram-se crescente com a progressão das lesões na região suprabasal com distribuição difusa, bem como a proteína Bcl-2. Observou-se diferença descritiva e quantitativa significante entre as proteínas p53 (DO-7) e p53 mutada (PAb-240) nos três grupos analisados, sendo que o anticorpo DO-7 revelou uma expressão mais elevada do que o PAb-240. A expressão da proteína Ki-67 mostrou-se elevada na região suprabasal de todos os grupos embora não tenha apresentado diferença significativa entre eles. Os casos de queilite com e sem displasia epitelial revelaram diferença significativa apenas para os marcadores p53 mutado (PAb-240) e para Bcl- 2. A expressão desses marcadores e do p53 (DO-7) revelaram-se mais elevada nos casos sem displasia epitelial. A expressão detectada neste estudo para esses marcadores em todas as lesões sugere que o desequilíbrio na regulação da apoptose e da proliferação celular ocorre numa fase inicial do desenvolvimento das lesões pré-malignas, inclusive nas lesões onde morfologicamente não é possível detectar nenhuma alteração ainda. Estes dados reforçam a importância do estudo de imunomarcadores envolvidos na carcinogênese bucal para avaliação do prognóstico de lesões pré-malignas e malignas e consequentemente a indicação de procedimentos terapêuticos e preventivos mais eficazes

Comparative analysis of the action of anabolic steroids on the gingiva and reproductive system of rats (Rattus norvegicus)

Os esteróides anabólicos-androgênicos (EAA) se caracterizam como um grupo de compostos naturais e sintéticos formados a partir da testosterona e seus derivados e foram desenvolvidos com finalidade terapêutica. No entanto, a partir da década de 90 o seu uso tem sido considerado um problema de saúde pública; e o seu consumo aumentado entre atletas profissionais e amadores que usam a medicação até 100 vezes acima da dose recomendada. Os efeitos adversos mais comuns relacionados ao uso dos EAA são alterações hepáticas, endócrinas, músculo-esqueléticas, cardiovasculares, imunológicas, reprodutivas, psicológicas, efeitos virilizantes e feminilizantes; e efeitos tóxicos. Apesar de diversos efeitos deletérios, os EAA em dose e freqüência adequada podem ter efeitos benéficos no reparo de feridas, revertendo os efeitos de corticosteróides. O objetivo deste trabalho foi avaliar os efeitos de doses suprafisiológicas (10mg/semana, por 60 dias) do EAA decanoato de nandrolona em 32 ratos (Rattus norvegicus), sendo divididos igualmente para o grupo experimental e controle (8 fêmeas e 8 machos para cada grupo) através da macroscopia, microscopia e morfometria. Os resultadosmostraram que os animais do grupo controle ganharam mais peso ao final do tratamento do que os animais tratados. Os ovários e testículos apresentaram atrofiaenquanto a hipertrofia foi observada nos úteros e próstatas, com diferença de peso significativa estatisticamente em todos os órgãos entre o grupo experimental e controle. Nos testículos, a contagem do número de células de Sertoli não apresentou diferença estatística, assim como no percentual de fibras colágenas entre o grupo experimental e controle. A média da altura das células epiteliais nas próstatas dos animais tratados apresentou-se maior que as do controle. Os ovários das ratas medicadas apresentaram diminuição de corpos lúteos e folículos atrésicos. Os resultados encontrados indicam que as altas doses do EAA decanoato de nandrolona causam alterações macroscópicas e morfológicas nos sistemas reprodutores de machos e fêmeas, podendo ser irreversíveis. O efeito benéfico do uso de EAA na síntese de colágeno não foi observado nos fragmentos de gengiva analisados.The anabolic-androgenic steroids (AAS) are characterized as a group of natural and synthetic compounds formed from testosterone and derivatives, and have been developed for therapeutic purposes. However, after the 1990s, their utilization has been considered a public health problem and the intake increased among professional and amateur athletes, who ingest up to 100 times the recommended dose of the drug. The most common adverse effects related to utilization of AAS are hepatic, endocrine, muscle-skeletal, cardiovascular, immunological, reproductive and psychological alterations; masculinizing and feminizing effects; and toxic effects. Despite the several harmful effects, utilization of AAS at adequate dose and frequency may have beneficial effects on wound repair, reverting the effects of corticosteroids. This study evaluated the effects of supraphysiological doses (10mg/week, for 60 days) of the AAS nandrolone decanoate in 32 rats (Rattus norvegicus), equally divided into experimental and control groups (8 females and 8 males for each group), by macroscopic, microscopic and morphometric analyses. The results revealed that animals in the control group gained more weight at treatment completion than treated animals. The ovaries and testicles presented atrophy, and hypertrophy of uterus and prostates was observed, with statistically significant difference in weight in all organs between the experimental and control groups. In the testicles, counting of the number of Sertoli cells and the percentage of collagen fibers did not present statistically significant difference between the experimental and control groups. The mean height of epithelial cells in the prostates of treated animals was greater in treated animals than in the control group. The ovaries of treated rats exhibited reduction in corpora lutea and atresic follicles. The results indicated that high doses of AAS nandrolone decanoate caused macroscopic and morphological alterations in the reproductive systems of males and females, which may be irreversible. The beneficial effect of utilization of AAS on the collagen synthesis was not observed on gingival fragments analyze

Aberrant DNA methylation of cancer-associated genes in gastric cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC-EURGAST)

Epigenetic events have emerged as key mechanisms in the regulation of critical biological processes and in the development of a wide variety of human malignancies, including gastric cancer (GC), however precise gene targets of aberrant DNA methylation in GC remain largely unknown. Here, we have combined pyrosequencing-based quantitative analysis of DNA methylation in 98 GC cases and 64 controls nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort and in cancer tissue and non-tumorigenic adjacent tissue of an independent series of GC samples. A panel of 10 cancer-associated genes (CHRNA3, DOK1, MGMT, RASSF1A, p14ARF, CDH1, MLH1, ALDH2, GNMT and MTHFR) and LINE-1 repetitive elements were included in the analysis and their association with clinicopathological characteristics (sex, age at diagnosis, anatomical sub-site, histological sub-type) was examined. Three out of the 10 genes analyzed exhibited a marked hypermethylation, whereas two genes (ALDH2 and MTHFR) showed significant hypomethylation, in gastric tumors. Among differentially methylated genes, we identified new genes (CHRNA3 and DOK1) as targets of aberrant hypermethylation in GC, suggesting that epigenetic deregulation of these genes and their corresponding cellular pathways may promote the development and progression of GC. We also found that global demethylation of tumor cell genomes occurs in GC, consistent with the notion that abnormal hypermethylation of specific genes occurs concomitantly with genome-wide hypomethylation. Age and gender had no significant influence on methylation states, but an association was observed between LINE-1 and MLH1 methylation levels with histological subtype and anatomical sub-site. This study identifies aberrant methylation patters in specific genes in GC thus providing information that could be exploited as novel biomarkers in clinics and molecular epidemiology of GC. (C) 2011 Elsevier Ireland Ltd. All rights reserved