RESUMO
Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas without effective therapeutics. Bioinformatics was used to identify potential therapeutic targets. Paired Box (PAX), Eyes Absent (EYA), Dachsund (DACH) and Sine Oculis (SIX) genes, which form a regulatory interactive network in Drosophila, were found to be dysregulated in human MPNST cell lines and solid tumors. We identified a decrease in DACH1 expression, and increases in the expressions of PAX6, EYA1, EYA2, EYA4, and SIX1-4 genes. Consistent with the observation that half of MPNSTs develop in neurofibromatosis type 1 (NF1) patients, subsequent to NF1 mutation, we found that exogenous expression of the NF1-GTPase activating protein-related domain normalized DACH1 expression. EYA4 mRNA was elevated more than 100-fold as estimated by quantitative real-time PCR in most MPNST cell lines. In vitro, suppression of EYA4 expression using short hairpin RNA reduced cell adhesion and migration and caused cellular necrosis without affecting cell proliferation or apoptotic cell death. MPNST cells expressing shEYA4 either failed to form tumors in nude mice or formed very small tumors, with extensive necrosis but similar levels of proliferation and apoptosis as control cells. Our findings identify a role of EYA4 and possibly interacting SIX and DACH proteins in MPNSTs and suggest the EYA4 pathway as a rational therapeutic target.
Assuntos
Neoplasias Experimentais/genética , Neoplasias de Bainha Neural/genética , Interferência de RNA , Transativadores/genética , Animais , Western Blotting , Linhagem Celular Tumoral , Células Cultivadas , Análise por Conglomerados , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Camundongos , Camundongos Nus , Necrose , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Neoplasias de Bainha Neural/metabolismo , Neoplasias de Bainha Neural/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Fator de Transcrição PAX6 , Fatores de Transcrição Box Pareados/genética , Fatores de Transcrição Box Pareados/metabolismo , Proteínas Tirosina Fosfatases/genética , Proteínas Tirosina Fosfatases/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transativadores/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transplante HeterólogoRESUMO
Bloom's syndrome (BS) is a rare recessive disorder caused by germline mutation of the BLM gene. Individuals with BS manifest growth retardation, immunodeficiency, and a predisposition to cancer. In this report, we describe an individual with BS and multiple colonic adenomas reminiscent of familial adenomatous polyposis coli (FAP). Molecular studies revealed APC mutations in 4 of 6 adenomas, including 2 adenomas with the identical APC mutation and microsatellite instability in 1 of 6 adenomas. These results demonstrate similar pathways to colorectal neoplasia in BS as in the normal population and suggest that individuals with BS may be particularly susceptible to colorectal neoplasia.
Assuntos
Adenoma/patologia , Síndrome de Bloom/patologia , Neoplasias do Colo/patologia , Adenoma/etiologia , Adenoma/genética , Adulto , Síndrome de Bloom/complicações , Síndrome de Bloom/genética , Neoplasias do Colo/etiologia , Neoplasias do Colo/genética , Humanos , Masculino , Repetições de MicrossatélitesAssuntos
Processamento Alternativo , Proteínas do Citoesqueleto/genética , Neoplasias Neuroepiteliomatosas/genética , Neurônios/metabolismo , Proteína da Polipose Adenomatosa do Colo , Animais , Células Cultivadas , Cerebelo/citologia , Cerebelo/metabolismo , DNA/química , DNA/genética , Análise Mutacional de DNA , Expressão Gênica , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Meduloblastoma/genética , Meduloblastoma/patologia , Mutação , Neoplasias Neuroepiteliomatosas/patologia , Neurônios/citologia , Polimorfismo Conformacional de Fita Simples , RNA/genética , RNA/metabolismo , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Medula Espinal/citologia , Medula Espinal/embriologia , Medula Espinal/metabolismo , Células Tumorais CultivadasRESUMO
Mutations in the tumor suppressor gene APC invariably lead to the development of colorectal cancer. The vast majority of these mutations are nonsense or frameshifts resulting in nonfunctional, truncated APC protein products. Eleven cyclin-dependent kinase (CDK) consensus phosphorylation sites have been identified in the frequently deleted carboxyl-terminal region of APC; loss of these phosphorylation sites by mutation could therefore compromise the ability of APC to inhibit cell growth. This report demonstrates that immunoprecipitates of full-length, but not truncated, APC protein include a mitosis-specific kinase activity in vivo. Biochemical and Western analysis of these immunoprecipitates confirms the presence of the CDK p34(cdc2). We also show that APC is a substrate for recombinant human p34(cdc2)-cyclin B1. Modification of APC by p34(cdc2) implicates phosphorylation as a mechanism for regulating APC function via a link to the cell cycle.
