Navegando por Palavras-chave "4-Nitroquinoline 1-oxide"
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- ItemSomente MetadadadosAlkylation-induced genotoxicity as a predictor of DNA repair deficiency following experimental oral carcinogenesis(Springer, 2012-04-01) Carvalho, Juliana Gonçalves [UNIFESP]; Noguti, Juliana [UNIFESP]; Silva, Victor Hugo Pereira da [UNIFESP]; Dedivitis, Rogerio Aparecido; Franco, Marcello Fabiano de [UNIFESP]; Ribeiro, Daniel Araki [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Ana Costa Hosp & Santa Casa SantosThe aim of this study was to evaluate alkylation induced genotoxicity as a result of DNA repair deficiency during 4-nitroquinoline 1-oxide (4NQO)-induced rat tongue carcinogenesis by means of single cell gel (comet) assay. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12, and 20 weeks. Ten animals were used as negative control. Blood samples and oral mucosa cells collected from all animals were divided into two aliquots of 20 mu L each to study basal DNA damage and DNA damage due to genotoxin sensitivity. the first aliquot was processed immediately for comet assay to assess basal DNA damage. the second aliquot was treated with a known genotoxin, methylmetanesulfonate. Significantly greater DNA damage was noticed to oral mucosa cells from 4, and 12 weeks post-treatment. Peripheral blood cells did show statistically significant differences (P < 0.05) after 20 weeks-group (squamous cell carcinoma). in conclusion, alkylation induced genotoxicity as a result of DNA repair deficiency is present in oral mucosa cells following oral experimental carcinogenesis.
- ItemSomente MetadadadosGenomic instability in blood cells is able to predict the oral cancer risk: an experimental study in rats(Springer, 2008-10-01) Ribeiro, Daniel Araki [UNIFESP]; Grilli, Daniela Gimenes [UNIFESP]; Salvadori, Daisy Maria Favero; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)This study was undertaken to investigate the genomic instability on blood cells during 4-nitroquinoline 1-oxide (4NQO)-induced rat tongue carcinogenesis by means of single cell gel (comet) and micronucleus assays. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12, and 20 weeks. Ten animals were used as negative control. Although no histopathological abnormalities were induced in the epithelium after 4 weeks of carcinogen exposure, genetic damage was found in blood cells as depicted by the mean tail moment and an increase of micronucleated polychromatic erythrocytes. After 12 and 20 weeks treatment, the same picture occurred, being the strong effect observed in the micronucleus induction. These periods correspond to pre-neoplastic lesions and well-differentiated squamous cell carcinomas, respectively. Taken together, our results support the idea that genomic instability on blood cells appears to be associated with the risk and progression of oral cancer, being a reliable tool for detecting early systemic conditions of malignancy.
- ItemSomente MetadadadosNo mutations found in exon 2 of gene p16CDKN2A during rat tongue carcinogenesis induced by 4-nitroquinoline-1-oxide(Springer, 2009-02-01) Minicucci, Eliana Maria; Silva, Glenda Nicioli da; Ribeiro, Daniel Araki [UNIFESP]; Favero Salvadori, Daisy Maria; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)The medium-term tongue carcinogenesis assay is a useful model for studying oral squamous cell carcinomas phase by phase. the present study aimed to investigate mutations in exon 2 of gene p16CDKN2A during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO) using direct DNA-sequencing method. A total of 30 male Wistar rats were treated with 4-nitroquinoline 1-oxide (4NQO) in drinking water for 4, 12, and 20 weeks at 50 ppm dose. Ten animals were used as negative control. No histopathological changes in tongue epithelia were observed among controls or in the group treated for 4 weeks with 4NQO. Following 12-week treatment, hyperplasia and epithelial dysplasia were found in mild and moderate forms. At 20 weeks, the tongue presented moderate and/or severe oral dysplasia and squamous cell carcinoma, with squamous cell carcinoma in the majority of animals. No mutations were found in any experimental period evaluated that corresponded to normal oral mucosa, hyperplasia, dysplasia and squamous cell carcinomas. Taken together, our results suggest that p16CDKN2A mutations in exon 2 are not involved in the multistep tongue carcinogenesis of Wistar rats induced by 4NQO.
- ItemSomente MetadadadosProtective effects of purple carrot extract (Daucus carota) against rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide(Humana Press Inc, 2018) Soares, Glaucia Resende [UNIFESP]; Moura, Carolina Foot Gomes de [UNIFESP]; Silva, Marcelo Jose Dias; Vilegas, Wagner; Santamarina, Aline Boveto [UNIFESP]; Pisani, Luciana Pellegrini [UNIFESP]; Estadella, Debora [UNIFESP]; Ribeiro, Daniel Araki [UNIFESP]The aim of this study was to evaluate the chemopreventive potential of purple carrot extract following rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO). For this purpose, histopathological analysis, proliferative status, antioxidant activity and inflammatory status were investigated in this setting. A total of 20 male rats were distributed into four groups as follows (n = 5 per group): Group 1-free access to water and commercial diet for 12 weeks
- ItemSomente MetadadadosThe role of the TP53 gene during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide(Elsevier B.V., 2011-07-01) Minicucci, Eliana Maria; Ribeiro, Daniel Araki [UNIFESP]; Silva, Glenda Nicioli da; Pardini, Maria Inês de Moura Campos; Montovani, Jair Cortez; Salvadori, Daisy Maria Favero; Universidade Federal de São Paulo (UNIFESP); São Paulo State UnivThe medium-term tongue carcinogenesis assay is a useful model for studying oral squamous cell carcinomas phase by phase. the aim of the present study was to investigate the expression of p53 by immunohistochemistry and examine the DNA sequence of exons 5, 6, 7, and 8 of Tp53 for mutations during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO). A total of 30 male Wistar rats were treated with 4-nitroquinoline 1-oxide in their drinking water for 4, 12, and 20 weeks at a dose of 50 ppm. Ten animals were used as negative controls. No histopathological changes in the tongue epithelia were observed in the control group or in the treatment group after 4 weeks of 4NQO. Following 12 weeks of treatment, hyperplasia as well as epithelial dysplasia was found in both mild and moderate forms. At 20 weeks, moderate and/or severe oral dysplasia and squamous cell carcinoma of the tongue were found, and the majority of animals had squamous cell carcinoma. the levels of p53 protein were increased (p < 0.05) in pre-neoplastic lesions and in squamous cell carcinomas in some of the tumor cells in squamous cell carcinomas. No mutations were found in any of the exons that were evaluated after the 4-, 12-, or 20-week treatments. Taken together, our results suggest that p53 expression may be an important event in the malignant conversion, whereas Tp53 mutations are not involved in the multi-step tongue carcinogenesis of Wistar rats induced by 4NQO. (C) 2010 Elsevier GmbH. All rights reserved.
- ItemSomente MetadadadosWnt/beta-catenin signalling pathway following rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide(Elsevier B.V., 2010-02-01) Cuzzuol Fracalossi, Ana Carolina [UNIFESP]; Silva, Marcelo de Souza [UNIFESP]; Oshima, Celina Tizuko Fujiyama [UNIFESP]; Ribeiro, Daniel Araki [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)The Wnt/beta-catenin signaling pathway plays an important role in development, tissue homeostasis, and regeneration. Inappropriate activation of the Writ pathway is linked to a wide range of human cancers. the purpose of this study was to characterize the Wnt/beta-catenin signaling pathway as depicted by the expression of Wnt1, Frizzled-1, Wnt5a. Frizzled-5 and beta-catenin during 4NQO-induced rat tongue carcinogenesis by immunohistochemistry. Male Wistar rats were distributed into three groups of 10 animals each and treated with 4NQO solution at 50 ppm through their drinking water for 4,12, and 20 weeks. Ten animals were used as control group. No histopathological abnormalities were induced in the epithelium after 4 weeks of carcinogen exposure; however, an overexpression of Wnt5a was noticed when compared to control group (p<0.05). the Wnt1 showed significant differences (p<0.05) in pre-neoplastic lesions at 12 weeks following carcinogen exposure. in well-differentiated squamous cell carcinoma induced after 20 weeks of treatment with 4NQO, Wnt1 was expressed in the majority of the dysplasic cells and tumor cells. This was statistically significant (p<0.05). No significant differences (p>0.05) were found in expression of Frizzled-1, Frizzled-5 or beta-catenin following oral carcinogenesis. Taken together, our results support the belief that expression of Wnt1 and Wnt5a is related to malignant transformation and conversion of oral mucosa. (C) 2009 Elsevier Inc. All rights reserved.