Identification of p21WAF1/CIP1 as a direct target of EWS-Fli1 oncogenic fusion protein
Identification of p21WAF1/CIP1 as a direct target of EWS-Fli1 oncogenic fusion protein
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DOI：
10.1074/jbc.m211470200
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发表时间：
2003-04-25
影响因子：
4.8
通讯作者：
Iwamoto, Y
中科院分区：
文献类型：
--
作者：
Nakatani, F;Tanaka, K;Iwamoto, Y
易位t（11;22）是一种核型异常，在超过90%的尤文氏家族肿瘤中检测到。这种易位导致EWS-Fli 1融合基因，该基因已被证明是一种有效的单步转化基因。我们以前报道过EWS-Fli 1融合蛋白的抑制改变了G（1）调节性细胞周期蛋白和细胞周期蛋白依赖性激酶抑制剂在mRNA和蛋白水平的表达，导致尤文氏家族肿瘤细胞系G（1）生长停滞。这些数据表明，G（1）调节分子可能是EWS-Fli 1融合蛋白的靶点，EWS-Fli 1融合蛋白作为异常转录因子发挥作用。通过使用电泳迁移率变动分析，我们在这里显示EWS-Fli 1融合蛋白与ETS共有序列的直接关联，这些序列位于p21（WAF 1/CIP 1）基因的启动子中。报告基因分析表明，p21（WAF 1/CIP 1）启动子的活性受到EWS-Fli 1融合蛋白通过启动子中至少两个ETS结合位点的负调控。EWS-Fli 1与p300共反式激活因子相互作用并抑制其组蛋白乙酰转移酶活性，这可能是EWS-Fli 1下调p21（WAF 1/CIP 1）的原因。在组蛋白去乙酰化酶抑制剂的存在下，尤文氏家族肿瘤细胞的组蛋白乙酰转移酶活性恢复，导致p21的诱导，并且细胞生长被显著抑制。这些结果表明，p21（WAF 1/CIP 1）可能是EWS-Fli 1的直接靶点之一，并且p21（WAF 1/CIP 1）可以作为尤文氏家族肿瘤分子治疗的靶点。
Translocation t(11;22) is a karyotypic abnormality detected in over 90% of Ewing's family tumors. This translocation results in the EWS-Fli1 fusion gene, which has been shown to be a potent, single-step transforming gene. We reported previously that suppression of the EWS-Fli1 fusion protein altered the expression of G(1) regulatory cyclins and cyclin-dependent kinase inhibitors both at mRNA and protein levels, resulting in G(1) growth arrest in Ewing's family tumor cell lines. These data suggest that the G(1) regulatory molecules may be targets of the EWS-Fli1 fusion protein, which functions as an aberrant transcription factor. By using electrophoretic mobility shift assays, we show here the direct association of EWS-Fli1 fusion protein with ETS consensus sequences, which are in the promoter of the p21(WAF1/CIP1) gene. Reporter gene assays revealed that the activity of the p21(WAF1/CIP1) promoter is negatively regulated by EWS-Fli1 fusion protein through at least two ETS-binding sites in the promoter. EWS-Fli1 interacted with p300 cotransactivator and suppressed its histone acetyltransferase activity, which may explain the down-regulation of p21(WAF1/CIP1) by EWS-Fli1. In the presence of a histone deacetylase inhibitor, the histone acetyltransferase activity of the Ewing's family tumor cell was recovered resulting in the induction of p21, and the cell growth was dramatically inhibited. These results demonstrated that p21(WAF1/CIP1) might be one of the direct targets of EWS-Fli1, and that p21(WAF1/CIP1) could serve as a target for a molecularly based therapy for Ewing's family tumors.