RESUMO
BACKGROUND: Several cancer-related genes are silenced by promoter hypermethylation in skin cancers. However, to date the somatic epigenetic events that occur in cutaneous squamous cell carcinoma (SCC) tumorigenesis have not been well defined. OBJECTIVES: To examine epigenetic abnormalities of FOXE1, a gene located on chromosome 9q22, a region frequently lost in SCC. METHODS: We investigated the methylation status of FOXE1 in 60 cases of cutaneous SCC by methylation-specific polymerase chain reaction, and comparatively examined mRNA and protein expression by real-time polymerase chain reaction and Western blot, respectively. RESULTS: We found a higher frequency of FOXE1 promoter hypermethylation in SCCs (55%), as compared with the adjacent uninvolved skin (12%) and blood control samples (9.5%). FOXE1 methylation was frequently seen in association with a complete absence of or downregulated gene expression. Treatment with the demethylating agent 5-Aza-2'-deoxycytidine resulted in profound reactivation of FOXE1 expression. CONCLUSIONS: These results indicate that FOXE1 is a crucial player in development of cutaneous SCC.
Assuntos
Carcinoma de Células Escamosas/genética , Metilação de DNA , Fatores de Transcrição Forkhead/genética , Neoplasias Cutâneas/genética , Idoso , Antimetabólitos Antineoplásicos/uso terapêutico , Azacitidina/análogos & derivados , Azacitidina/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/metabolismo , DNA de Neoplasias/genética , Decitabina , Feminino , Fatores de Transcrição Forkhead/biossíntese , Predisposição Genética para Doença , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas de Neoplasias/biossíntese , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , RNA Neoplásico/genética , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/metabolismoRESUMO
BACKGROUND: FOXE1 is a candidate tumour suppressor gene at human chromosome locus 9q22. This is a region frequently lost in squamous cell cancer. OBJECTIVES: To assess the influence of FOXE1 variations on genetic susceptibility to cutaneous squamous cell carcinoma (SCC). METHODS: We performed mutational analysis of FOXE1 in 320 DNA samples isolated from 60 SCC specimens, 60 adjacent histologically normal skin samples and 200 blood samples. RESULTS: No somatic mutations were evident. Instead the polyalanine tract showed marked variation in its length between samples from patients with SCC and normal controls. CONCLUSIONS: These results imply that another tumour suppressor gene at this locus may be more important than FOXE1 in skin carcinogenesis and suggest that variation in the FOXE1 polyalanine tract length predisposes to cutaneous SCC.
Assuntos
Carcinoma de Células Escamosas/genética , Fatores de Transcrição Forkhead/genética , Genes Supressores de Tumor , Neoplasias Cutâneas/genética , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/genética , Estudos de Casos e Controles , Análise Mutacional de DNA , Feminino , Humanos , Masculino , MutaçãoRESUMO
AIMS: Microcosm experiments simulating an oil spill event were performed to evaluate the response of the natural microbial community structure of Messina harbour seawater following the accidental load of petroleum. METHODS AND RESULTS: An experimental harbour seawater microcosm, supplemented with nutrients and crude oil, was monitored above 15 days in comparison with unpolluted ones (control microcosms). Bacterial cells were counted with a Live/Dead BacLight viability kit; leucine aminopeptidase, beta-glucosidase, alkaline phosphatase, lipase and esterase enzymes were measured using fluorogenic substrates. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil addition stimulated an increase of the total bacterial abundance, leucine aminopeptidase and phosphatase activity rates, as well as a change in the community structure. This suggested a prompt response of micro-organisms to the load of petroleum hydrocarbons. CONCLUSIONS: The present study on the viability, specific composition and metabolic characteristics of the microbial community allows a more precise assessment of oil pollution. Both structural and functional parameters offer interesting perspectives as indicators to monitor changes caused by petroleum hydrocarbons. SIGNIFICANCE AND IMPACT OF THE STUDY: A better knowledge of microbial structural successions at oil-polluted sites is essential for environmental bioremediation. Data obtained in microcosm studies improve our understanding of natural processes occurring during oil spills.