RESUMO
PURPOSE: Constitutive activation of ERK1/2 controls proliferation of uveal melanoma cells. Because an autocrine fibroblast growth factor (FGF) activation loop controls ERK1/2 activation in many cancers, this study was conducted to examine the role of the FGF/FGF receptor autocrine loop in the ERK1/2-dependent proliferation and survival of uveal melanoma cells. METHODS: Primary tumors and cell lines (OCM-1, MKT-BR, SP6.5, Mel270 and 92.1) were used to define the role of the FGF/FGFR system in human uveal melanoma. Cell proliferation was assessed by MTT-staining, and apoptosis was quantified by flow cytometry. Specific pharmacologic inhibitors of ERK1/2 and FGFR1, an anti-FGF2 neutralizing antibody and an antisense oligonucleotide directed against FGF2 were used to analyze signaling in the FGF/FGFR autocrine loop. RESULTS: FGF1, FGF2, and their FGFR1 receptor were strongly expressed in the primary uveal melanomas. All five uveal melanoma cell lines expressed and secreted FGF2. They also expressed FGFR1. Cell proliferation was strongly reduced by the antisense oligonucleotide-mediated depletion of endogenous FGF2, immunoneutralization of secreted FGF2, and pharmacologic inhibition of FGFR1. The FGF2/FGFR1-mediated signaling pathway was identified by showing that inhibition of either FGF2 or FGFR1 reduced ERK1/2 activation, cell proliferation, and survival. CONCLUSIONS: The FGF/FGFR/ERK signaling pathway may be a target for therapeutic strategies against uveal melanoma.
Assuntos
Comunicação Autócrina/fisiologia , Proliferação de Células , Fator 2 de Crescimento de Fibroblastos/metabolismo , Melanoma/metabolismo , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Neoplasias Uveais/metabolismo , Apoptose , Western Blotting , Sobrevivência Celular , Inibidores Enzimáticos/farmacologia , Fator 2 de Crescimento de Fibroblastos/antagonistas & inibidores , Citometria de Fluxo , Humanos , Melanoma/patologia , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Oligonucleotídeos Antissenso/farmacologia , Proteínas Proto-Oncogênicas B-raf/fisiologia , RNA Mensageiro/metabolismo , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sais de Tetrazólio/metabolismo , Tiazóis/metabolismo , Tionucleotídeos/farmacologia , Células Tumorais Cultivadas , Neoplasias Uveais/patologiaRESUMO
Gains and losses of chromosomes 1, 3, 6 and 8 are nonrandom chromosomal aberrations in uveal melanoma. Monosomy 3 is the most frequent abnormality and is associated with poor prognosis. To identify regions of allelic loss on the short arm of chromosome 1 and to investigate if these alterations contribute to uveal melanoma progression, we performed microsatellite analysis of 10 loci in 70 uveal melanomas. A total of 51 tumors were obtained from patients with clinical follow-up data, 19 tumors were from recent patients without follow-up. Loss of heterozygosity (LOH) of at least 1 marker was more frequent in tumors with monosomy 3 (40%) than in tumors with disomy 3 (10%). In particular, loss of the entire short arm of chromosome 1 was only observed in tumors with monosomy 3 (p = 0.0001). By comparing the extent of 1p LOH in all tumors with monosomy 3, we were able to define a smallest region of overlap (SRO) of approximately 55 Mb, which is flanked by markers D1S507 and D1S198. On the basis of our data and published cytogenetic data, we propose that 1p31 harbors genes involved in the progression of uveal melanoma with monosomy 3.
