The role of the TP53 gene during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

DNA methylation in the CTCF-binding site I and the expression pattern of the H19 gene: Does positive expression predict poor prognosis in early stage head and neck carcinomas?

Loss of allele-specific expression by the imprinted genes IGF2 and H19 has been correlated with a differentially methylated region (DMR) upstream to the H19 gene. The H19-DMR contains seven potential CCCTC-binding factor (CTCF) binding sites. CTCF is a chromatin insulator and a multifunctional transcription factor whose binding to the H19-DMR is suppressed by DNA methylation. Our study included a group of 41 head and neck squamous cell carcinoma (HNSCC) samples. The imprinting status of the H19 gene was analyzed in 11 out of 35 positive cases for H19 gene expression, and only 1 of them showed loss of imprinting. We detected a significant correlation (P=0.041, Fisher's exact test) between H19 expression and tumor recurrence. Among H19 positive cases, six were T2, in which five developed recurrence and/or metastasis. Inversely, in the group of tumors that showed no H19 gene expression, 5 out of 24 were T2 and only I presented regional recurrence. These data support the hypothesis that H19 expression could be used as a prognostic marker to indicate recurrence in early stage tumors. We also examined the methylation of the CTCF binding site 1 in a subgroup of these samples. The H19 gene silencing and loss of imprinting were not correlated with the methylation pattern of the CTCF binding site 1. However, the significant correlation between H19 expression and tumor recurrence suggest that this transcript could be a marker for the progression of HNSCC. (c) 2005 Wiley-Liss, Inc.

The 434(G > C) polymorphism in the eosinophil cationic protein gene and its association with tissue eosinophilia in oral squamous cell carcinomas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gene expression profiling reveals molecular marker candidates of laryngeal squamous cell carcinoma

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gene Mutations and Polymorphisms of TP53 and FHIT in Chronic Esophagitis and Esophageal Carcinoma

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Differentially expressed genes in giant cell tumor of bone

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Alterations of the TP53 Gene in Gastric and Esophageal Carcinogenesis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Association of matrix metalloproteinase-8 gene variation with breast cancer prognosis

Animal and cell studies indicate an inhibitory effect of matrix metalloproteinase-8 (MMP8) on tumorigenesis and metastasis. We investigated whether MMP8 gene variation was associated with breast cancer metastasis and prognosis in humans. We first studied nine tagging single nucleotide polymorphisms (SNP) in the MMP8 gene in 140 clinically and pathologically well-characterized breast cancer patients. Four of the SNPs were found to be associated with lymph node metastasis, the most pronounced being a promoter SNP (rs11225395) with its minor allele (T) associating with reduced susceptibility to lymph node metastasis (P = 0.02). This SNP was further evaluated for association with cancer relapse and survival among a cohort of similar to 1,100 breast cancer patients who had been followed for cancer recurrence and mortality for a median of 7.1 years. The T allele was associated with reduced cancer relapse and greater survival, particularly among patients with earlier stage cancer. Among patients of tumor-node-metastasis stage 0 to 11, the adjusted hazard ratio of disease-free survival was 0.7 [95% confidence interval (95% CI), 0.5-0.9] for patients carrying T allele compared with those homozygous for the C allele (P = 0.02). In vitro experiments showed that the T allele had higher promoter activity than the C allele in breast cancer cells. Electrophoretic mobility shift assays showed binding of nuclear proteins to the DNA sequence at the SNP site of the T allele but not that of the C allele. The data suggest that MMP8 gene variation may influence breast cancer prognosis and support the notion that MMP8 has an inhibitory effect on cancer metastasis.

Methylation status of CDH1 gene in samples of gastric mucous from brazilian patients with chronic gastritis infected by Helicobacter pylori

CONTEXTO:O câncer gástrico é uma das principais neoplasias que causam o óbito no Brasil e no mundo. Helicobacter pylori é um carcinógeno do tipo I relacionado à gastrite crônica. Diferenças no grau de virulência de suas cepas levam a maior risco de desenvolvimento de doenças gástricas. A metilação de ilhas CpGs está envolvida com o processo de tumorigênese em diferentes tipos de câncer. CDH1 é um gene supressor tumoral que, quando inativado, pode aumentar as chances de metástase. A metilação deste gene em estágios precoces da carcinogênese gástrica ainda não é totalmente compreendida. OBJETIVO: Investigar o padrão de metilação do gene CDH1 em amostras de gastrites crônicas e correlacionar com a presença do H. pylori. MÉTODOS: Foram usadas 60 biopsias de mucosas gástricas. A detecção de H. pylori foi realizada por PCR para o gene da urease C e a genotipagem com PCR para os genes cagA e vacA (região s e m). O padrão de metilação do gene CDH1 foi analisado usando a técnica de PCR e específica para a metilação e sequenciamento direto dos produtos de PCR. RESULTADOS: A bactéria H. pylori foi detectada em 90% das amostras de gastrites crônicas; destas, 33% portavam o gene cagA e 100% vacA s1. O genótipo vacA s2/m1 não foi detectado nas amostras analisadas. Metilação de CDH1 foi detectada em 63,3% das amostras de gastrites e 95% delas eram portadoras de H. pylori. CONCLUSÃO: Os resultados deste estudo sugerem que a metilação em CDH1 e a infecção pelo H. pylori são eventos frequentes em amostras de pacientes brasileiros com gastrite crônica e reforça a correlação entre infecção por H. pylori e inativação do gene CDH1 em estágios precoces da tumorigênese gástrica.

p53 gene analysis in childhood B non - Hodgkin's lymphoma

CONTEXTO: Alterações do gene supressor de tumor p53, como mutações e deleções, são lesões genéticas encontradas com maior freqüência nas neoplasias humanas, incluindo câncer de mama, pulmão e cólon. Entre as malignidades hematológicas, o gene 53 é freqüentemente mutado no linfoma de Burkitt, sendo detectadas mutações em 30-40% das amostras tumorais e em 70% das linhagens celulares. OBJETIVO: Analisar as alterações do gene p53 em crianças com linfoma não-Hodgkin de origem B. TIPO DE ESTUDO: Estudo descritivo. LOCAL: Centro de Oncologia Terciário. PARTICIPANTES: O estudo analisou 12 pacientes com linfoma não-Hodgkin B classificados como linfoma de Burkitt. A análise de possíveis mutações do gene p53 foi realizada pela técnica de PCR-SSCP dos exons 5, 6 ,7 e 8/9 do gene. RESULTADOS: Um padrão anormal de migração foi observado em quatro pacientes (33.3%), em um paciente no exon 6 e em três no exon 7. Os casos positivos incluíam dois pacientes que evoluíram para o óbito por progressão da doença. CONCLUSÃO: Esses resultados preliminares sugerem que as alterações do gene p53 são freqüentes em crianças com linfoma de Burkitt e podem contribuir para patogênese ou progressão da doença.

GLUCOCORTICOID-REGULATED GENE IN TRANSFORMED TO NORMAL PHENOTYPIC REVERSION

Glucocorticoid hormones modulate the actions of peptide growth factors and constitute important therapeutic tools as anti-inflammatory and anti-tumor agents. The C6 rat glioma cell line responds to glucocorticoids with changes in morphology and growth block. The hyper-responsive ST1 cell variant displays a dramatic phenotypic reversion under the influence of these hormones. Thus, the transformed and tumorigenic cells reversibly change to a normal and non-tumorigenic phenotype. In addition, the cells also produce a C-type retrovirus. We used poly A(+) mRNA from ST1 cells that had been treated with hydrocortisone to generate a cDNA library that was then screened, by differential hybridization,for glucocorticoid-responsive cellular sequences. The retroviral genomic RNA was used to generate a viral-specific probe. Cross hybridization led to the isolation of at least 4 cDNA clones of which 3 are cellular sequences and one corresponds to a retroviral gene. These clones were characterized by DNA sequencing and Northern blot hybridization analysis.

MKK3/6-p38 MAPK negatively regulates murine MMP-13 gene expression induced by IL-1 beta and TNF-alpha in immortalized periodontal ligament fibroblasts

Matrix metalloprotease-13 (MMP-13) or collagenase-3 is involved in a number of pathologic processes such as tumor metastasis and angiogenesis, osteoarthritis, rheumatoid arthritis and periodontal diseases. These conditions are associated with extensive degradation of both connective tissue and bone. This report examines gene regulation mechanisms and signal transduction pathways involved in Mmp-13 expression induced by proinflammatory cytokines in periodontal ligament (PDL) fibroblasts. Mmp-13 mRNA expression was increased 10.7 and 9.5 fold after stimulation with IL-1 beta (5 ng/mL) and TNF-alpha (10 ng/mL), respectively. However, inhibition of p38 MAPKinase with SB203580 resulted in significant (p < 0.001) induction (23.2 and 18.1 fold, respectively) of Mmp-13 mRNA as assessed by real time PCR. Negative regulation of IL-1 induced Mmp-13 expression was confirmed by inhibiting p38 MAPK gene expression with siRNA. Transient transfection of dominant negative forms of MKK3 and MKK6 also resulted in increased levels of Mmp-13 mRNA after IL-1 beta stimulation. Mmp-13 mRNA expression induced by TNF-alpha was decreased by JNK and ERK inhibition. Western blot and zymogram analysis indicated that Mmp-13 protein expression induced by the proinflammatory cytokines were also upregulated by inhibition of p38 MAPK. Reporter gene experiments using stable cell lines harboring 660-bp sequence of the murine Mmp-13 proximal promoter indicated that transcriptional mechanisms were at least partially involved in this negative regulation of Mmp-13 expression by p38 MAPK and upstream MKK3/6. These results suggest a negative transcriptional regulatory mechanism mediated by p38 MAPK and upstream MKK3/6 on Mmp-13 expression induced by proinflammatory cytokines in PDL fibroblasts. (c) 2005 Elsevier B.V./International Society of Matrix Biology. All rights reserved.

CDKN2A promoter methylation is related to the tumor location and histological subtype and associated with Helicobacter pylori flaA(+) strains in gastric adenocarcinomas

Promoter hypermethylation of CDKN2A (p16INK4A protein) is the main mechanism of gene inactivation. However, its association with Helicobacter pylori infection is a controversial issue. Therefore, we examined a series of gastric adenocarcinomas to assess the association between p16INK4A inactivation and H. pylori genotype (vacA, cagA, cagE, virB11 and flaA) according to the location and histological subtype of the tumors. p16INK4A expression and CDKN2A promoter methylation were found in 77 gastric adenocarcinoma samples by immunohistochemistry and methylation-specific PCR, respectively. Helicobacter pylori infection and genotype were determined by PCR. A strong negative correlation between immunostaining and CDKN2A promoter region methylation was found. In diffuse subtype tumors, the inactivation of p16INK4A by promoter methylation was unique in noncardia tumors (p = 0.022). In addition, H. pylori-bearing flaA was associated with non-methylation tumors (p = 0.008) and H. pylori strain bearing cagA or vacAs1m1 genes but without flaA was associated with methylated tumors (p = 0.022 and 0.003, respectively). Inactivation of p16INK4A in intestinal and diffuse subtypes showed distinct carcinogenic pathways, depending on the tumor location. Moreover, the process of methylation of the CDKN2A promoter seems to depend on the H. pylori genotype. The present data suggest that there is a differential influence and relevance of H. pylori genotype in gastric cancer development.

Secretion of tumor necrosis factor-alpha by mouse peritoneal macrophages in the presence of dental sealers, sealapex and endomethasone

After filling root canals, the healing process depends on the chemical composition or physical-chemical properties of the material used, among other factors. All root canal sealers, whether solid or plastic, are foreign matter for the body if they remain in permanent contact with apical and periapical tissues. As a result, the first organic reaction that occurs is an attempt to phagocytize the material. During phagocytosis, macrophages release a large number of cell mediators into the area, among which are cytokines that are essential in intercellular communication and in many physiological and pathophysiological processes. One of these cytokines is tumor necrosis factor-alfa (TNF-α), which acts through links to specific receptors on the cell membrane initiating a cascade of events leading to induction, activation, or inhibition of numerous cytokine-regulated genes in the cell nucleus. The release of TNF-α in a cell culture of mouse peritoneal macrophages incubated with three concentrations (25, 50, and 100 mg/ml) of two endodontic sealers was measured. The solutions containing the calcium hydroxide-based root canal sealer (Sealapex) released fewer units of TNF-α than solutions containing the zinc oxide and eugenol-based sealer (Endomethasone).

Cytokine gene variants and venous thrombotic risk in the BRATROS (BRAZILIAN THROMBOSIS STUDY)

Introduction: Venous thrombosis (VT) and inflammation are two closely related entities. In the present investigation we assessed whether there is a relation between genetic modifiers of the inflammatory response and the risk of VT. Materials and methods: 420 consecutive and unrelated patients with an objective diagnosis of deep VT and 420 matched controls were investigated. The frequencies of the following gene polymorphisms were determined in all subjects: TNF-α- 308 G/A, LT-α+ 252 A/G, IL-6-174 G/C, IL1-ra 86 bp VNTR, IL-10-1082 A/G and CD-31 125 C/G. Results: Overall odds ratio (OR) for VT related to TNF-α- 308 G/A, LT-α+ 252 A/G, IL-6-174 G/C, A1 allele (4 bp repeat) of the IL1-ra 86 bp VNTR, IL-10-1082 A/G and CD-31 125 C/G were respectively: 1.0 (CI95: 0.8-1.5), 1.3 (CI95: 1.0-1.7), 1.1 (CI95: 0.9-1.5), 1.6 (CI95: 1-2.5), 1.2 (CI95: 0.8-1.7) and 0.8 (CI95: 0.6-1.1). A possible interaction between polymorphisms was observed only for the co-inheritance of the mutant alleles of the LT-α+ 252 A/G and IL-10-1082 G/A polymorphisms (OR = 2; CI95: 1.1-3.8). The risk of VT conferred by factor V Leiden and FII G20210A was not substantially altered by co-inheritance with any of the cytokine gene polymorphisms. Conclusions: Cytokine gene polymorphisms here investigated did not significantly influence venous thrombotic risk. © 2006 Elsevier Ltd. All rights reserved.