As2O3-induced c-Src/EGFR/ERK signaling is via Sp1 binding sites to stimulate p21WAF1/CIP1 expression in human epidermoid carcinoma A431 cells
As2O3-induced c-Src/EGFR/ERK signaling is via Sp1 binding sites to stimulate p21WAF1/CIP1 expression in human epidermoid carcinoma A431 cells
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DOI：
10.1016/j.cellsig.2005.04.006
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发表时间：
2006-02-01
影响因子：
4.8
通讯作者：
Huang, HS
中科院分区：
文献类型：
--
作者：
Liu, ZM;Huang, HS
砷已被有效地用于治疗急性早幼粒细胞白血病，并可诱导人类实体瘤细胞周期阻滞或凋亡。以前，我们已经证明，As 2 O3可以诱导p21（WAF 1/CIP 1）（p21）在A431细胞中的表达，然后由于细胞毒性。目前，我们已经阐明了这些信号传导事件，并将其与EGF进行了比较。利用报告基因分析、RT-PCR和Western blotting技术，我们发现c-Src的激活可能是As_2O_3诱导EGFR/Ras/Raf/ERK信号转导的先决条件。此外，借助于5 ′-缺失和定点突变，我们证明Sp1结合位点，范围从-64到-84 bp，是As 2 O3或EGF调控的p21表达所必需的。最后，我们的实验利用放线菌酮提示的建议，mRNA或蛋白质的稳定性也有助于As 2 O3或EGF诱导的p21表达。综上所述，我们认为Sp1结合位点是As 2 O3通过c-Src/EGFR/Ras/Raf/ERK途径诱导p21基因转录所必需的。此外，转录后或翻译后稳定机制也是As_2O_3诱导p21表达所必需的。EGF诱导的p21表达可能涉及与A431细胞中As 2 O3介导的反应类似的机制。(c)2005年爱思唯尔公司All rights reserved.
Arsenic has been effectively used to treat acute promyelocytic leukemia, and can induce cell cycle arrest or apoptosis in human solid tumors. Previously, we have demonstrated that As2O3 can induce p21(WAF1/CIP1) (p21) expression in A431 cells and then due to cellular cytotoxicity. Presently, we have clarified these signaling events and compared them with EGF. Using reporter assay, RT-PCR and Western blotting, we show that c-Src activation might be a prerequisite for As2O3-induced EGFR/Ras/Raf/ERK signaling. Furthermore, with the aids of 5'-deletion and site-directed mutagenesis, we demonstrate that Sp1 binding sites, ranging from -64 to -84 bp, are essential for As2O3- or EGF-regulated p21 expression. Finally, our experiments utilizing cycloheximide prompt the suggestion that the stability of mRNA or protein also contributes to As2O3- or EGF-induced p21 expression. Taken together, we conclude that the Sp1 binding sites are required for As2O3-induced p21 gene transcription through c-Src/EGFR/Ras/Raf/ERK pathway. Furthermore, post-transcriptional or post-translational stabilization mechanism is also essential for As2O3-induced p21 expression. EGF-induced p21 expression may involve similar mechanisms as those that operate in the As2O3-mediated reactions in A431 cells. (c) 2005 Elsevier Inc. All rights reserved.