Dauphinot L, De Oliveira C, Melot T, Sevenet N, Thomas V, Weissman B E, Delattre O
INSERM U509, Laboratoire de Pathologie Moléculaire des Cancers, Institut Curie, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
Oncogene. 2001 May 31;20(25):3258-65. doi: 10.1038/sj.onc.1204437.
Ewing tumour is characterized by specific chromosome translocations which fuse EWS to a subset of genes encoding ETS transcription factors, most frequently FLI-1. We report the analysis of the expression of various cell cycle regulators both in Ewing tumour derived cell lines and in different cellular models with either inducible or constitutive EWS-FLI-1 cDNA expression. In Ewing cell lines, cyclin D1, CDK4, Rb, p27KIP1 and c-Myc were consistently highly expressed whereas p57KIP2, p15INK4B and p14ARF demonstrated undetectable or low expression levels. The amount of p16INK4A, p21CIP1, p18INKAC and CDK6 was variable from one cell line to the other. The inducible expression of EWS-FLI-1 led to a strong upregulation of c-Myc and a considerable downregulation of p57KIP2. Other proteins did not show evident modification. High c-Myc and very low p57KIP2 expression levels were also observed in neuroblastoma NGP cells constitutively expressing EWS-FLI-1 as compared to parental cells. Analysis of the p57KIP2 promoter indicated that EWS-FLI-1 downregulates, possibly through an indirect mechanism, the transcription of this gene. Finally, we show that ectopic expression of p57KIP2 in Ewing cells blocks proliferation through a complete G1 arrest. These results suggest that the modulation of p57(KIP2) expression by EWS-FLI-1 is a fundamental step in Ewing tumorigenesis.
尤因肉瘤的特征是特定的染色体易位，该易位将EWS与编码ETS转录因子的一组基因融合，其中最常见的是FLI-1。我们报告了对各种细胞周期调节因子在尤因肉瘤衍生细胞系以及具有诱导型或组成型EWS-FLI-1 cDNA表达的不同细胞模型中的表达分析。在尤因细胞系中，细胞周期蛋白D1、细胞周期蛋白依赖性激酶4（CDK4）、视网膜母细胞瘤蛋白（Rb）、p27KIP1和c-Myc始终高度表达，而p57KIP2、p15INK4B和p14ARF的表达水平检测不到或很低。p16INK4A、p21CIP1、p18INKAC和CDK6的量在不同细胞系之间有所不同。EWS-FLI-1的诱导表达导致c-Myc强烈上调以及p57KIP2显著下调。其他蛋白质未显示明显变化。与亲代细胞相比，在组成型表达EWS-FLI-1的神经母细胞瘤NGP细胞中也观察到高c-Myc和极低p57KIP2表达水平。对p57KIP2启动子的分析表明，EWS-FLI-1可能通过间接机制下调该基因的转录。最后，我们表明p57KIP2在尤因细胞中的异位表达通过完全的G1期阻滞来阻断增殖。这些结果表明，EWS-FLI-1对p57（KIP2）表达的调节是尤因肉瘤发生的一个基本步骤。
