RESUMO
Macrophages have a key role in tumor-associated pulmonary inflammation that supports the proliferation of tumor cells and promotes lung tumor growth. Although increased numbers of tumor-associated macrophages are linked to poor prognosis in lung cancer patients, little is known regarding the transcriptional mechanisms controlling recruitment of macrophages during lung tumorigenesis. Forkhead Box m1 (Foxm1) transcription factor is induced in multiple cell types within tumor lesions and its increased expression is associated with poor prognosis in patients with lung adenocarcinomas. To determine the role of Foxm1 in recruitment of tumor-associated macrophages, a mouse line with macrophage-specific Foxm1 deletion was generated (macFoxm1(-/-)). Lung tumorigenesis was induced using a 3-methylcholanthrene/butylated hydroxytoluene (BHT; 3,5-di-t-butyl-4-hydroxytoluene) tumor initiation/promotion protocol. Ablation of Foxm1 in macrophages reduced the number and size of lung tumors in macFoxm1(-/-) mice. Decreased tumorigenesis was associated with diminished proliferation of tumor cells and decreased recruitment of macrophages during the early stages of tumor formation. The expression levels of the pro-inflammatory genes iNOS, Cox-2, interleukin-1b (IL-1b) and IL-6, as well as the migration-related genes macrophage inflammatory protein-1 (MIP-1α), MIP-2 and MMP-12, were decreased in macrophages isolated from macFoxm1(-/-) mice. Migration of Foxm1-deficient macrophages was reduced in vitro. The chemokine receptors responsible for monocyte recruitment to the lung, CX(3)CR1 and CXCR4, were decreased in Foxm1-deficient monocytes. In co-transfection experiments, Foxm1 directly bound to and transcriptionally activated the CX(3)CR1 promoter. Adoptive transfer of wild-type monocytes to macFoxm1(-/-) mice restored BHT-induced pulmonary inflammation to the levels observed in control mice. Expression of Foxm1 in macrophages is required for pulmonary inflammation, recruitment of macrophages into tumor sites and lung tumor growth.
Assuntos
Movimento Celular/genética , Fatores de Transcrição Forkhead/genética , Neoplasias Pulmonares/genética , Macrófagos/metabolismo , Pneumonia/genética , Transferência Adotiva , Animais , Hidroxitolueno Butilado/análogos & derivados , Receptor 1 de Quimiocina CX3C , Quimiocina CCL3/genética , Quimiocina CCL3/metabolismo , Quimiocina CXCL2/genética , Quimiocina CXCL2/metabolismo , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Citometria de Fluxo , Proteína Forkhead Box M1 , Fatores de Transcrição Forkhead/metabolismo , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/metabolismo , Macrófagos/patologia , Metaloproteinase 12 da Matriz/genética , Metaloproteinase 12 da Matriz/metabolismo , Camundongos , Camundongos Knockout , Monócitos/metabolismo , Monócitos/transplante , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Pneumonia/induzido quimicamente , Pneumonia/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica , Receptores CXCR4/genética , Receptores CXCR4/metabolismo , Receptores de Citocinas/genética , Receptores de Citocinas/metabolismo , Receptores de HIV/genética , Receptores de HIV/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
The AML1-ETO fusion protein, which is present in 10-15% of cases of acute myeloid leukemia, is known to repress myeloid differentiation genes through DNA binding and recruitment of chromatin-modifying proteins and transcription factors in target genes. ChIP-chip analysis of human hematopoietic stem/progenitor cells transduced with the AML1-ETO fusion gene enabled us to identify 1168 AML1-ETO target genes, 103 of which were co-occupied by histone deacetylase 1 (HDAC1) and had lost the hyperacetylation mark at histone H4, and 264 showed a K9 trimethylation at histone H3. Enrichment of genes involved in hematopoietic differentiation and in specific signaling pathways was observed in the presence of these epigenetic modifications associated with an 'inactive' chromatin status. Furthermore, AML1-ETO target genes had a significant correlation between the chromatin marks studied and transcriptional silencing. Interestingly, AML1 binding sites were absent on a large number of selected AML1-ETO promoters and an Sp1 binding site was found in over 50% of them. Reversible silencing induced by the fusion protein in the presence of AML1 and/or Sp1 transcription factor binding site was confirmed. Therefore, this study provides a global analysis of AML1-ETO functional chromatin modifications and identifies the important role of Sp1 in the DNA binding pattern of AML1-ETO, suggesting a role for Sp1-targeted therapy in this leukemia subtype.
Assuntos
Cromatina/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Fator de Transcrição Sp1/metabolismo , Acetilação , Sítios de Ligação , Células Cultivadas , Imunoprecipitação da Cromatina , Subunidade alfa 2 de Fator de Ligação ao Core/antagonistas & inibidores , Epigênese Genética , Genômica , Células-Tronco Hematopoéticas/citologia , Histona Desacetilase 1/genética , Histona Desacetilase 1/metabolismo , Histonas/metabolismo , Humanos , Proteínas de Fusão Oncogênica/antagonistas & inibidores , Regiões Promotoras Genéticas/genética , RNA Mensageiro/genética , Proteína 1 Parceira de Translocação de RUNX1 , Reação em Cadeia da Polimerase em Tempo Real , Fator de Transcrição Sp1/antagonistas & inibidores , Fator de Transcrição Sp1/genética , Cordão Umbilical/citologia , Cordão Umbilical/metabolismoAssuntos
Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Subunidade gama Comum de Receptores de Interleucina/fisiologia , Interleucina-3/metabolismo , Leucemia Mieloide Aguda/metabolismo , Fator de Células-Tronco/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Proliferação de Células/efeitos dos fármacos , Feminino , Citometria de Fluxo , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
A cross-sectional study on noise-induced hearing loss and blood pressure was conducted in a steel mill company. Three hundred testees were selected by cluster sampling. They were physically examined and an audiometry was done. Only 151 workers, who had the highest hearing threshold at 4000 Hz and without any family history of hypertension or treatment of drugs on cardiovascular troubles, were selected as subjects in this study. Multiple regression analyses revealed that body mass index, employment duration, age and hearing loss explained a significant amount of variation in systolic and diastolic blood pressure (R2 = 0.16 and 0.12, respectively). There was no significant relationship between hearing loss and blood pressure. In order to adjust confounding factors, analyses of covariances were used and the results suggest that hearing loss is unrelated to blood pressure. It seems that hearing loss is not appropriate as a noise exposure index to measure the relationship between noise exposure and blood pressure.