Vulcano Francesca, Ciccarelli Carmela, Mattia Gianfranco, Marampon Francesco, Giampiero Macioce, Milazzo Luisa, Pascuccio Massimiliano, Zani Bianca M, Giampaolo Adele, Hassan Hamisa J
Section of Transfusion Methodologies, Department of Hermatology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
Exp Cell Res. 2006 May 15;312(9):1590-7. doi: 10.1016/j.yexcr.2006.01.017.
Valproic acid (VPA), a histone deacetylase inhibitor, causes differentiation in different cell lines and in a cell-specific manner; yet, its effect on megakaryocytic (MK) differentiation has not been studied. We evaluated whether VPA induces MK differentiation in a UT-7 cell line through histone acetylation in the GpIIIa gene region and activation of the ERK pathway. UT-7 cells, derived from megakaryoblastic leukemia, were treated with VPA at various concentrations, and the expression of differentiation markers as well as the gene expression profile was assessed. Flow cytometry, immunoblot analysis, and RT-PCR demonstrated that VPA induced the expression of the early MK markers GpIIIa (CD61) and GpIIb/IIIa (CD41) in a dose-dependent manner. The VPA-treated cells showed hyperacetylation of the histones H3 and H4; in particular, histone acetylation was found to have been associated with CD61 expression, in that the GpIIIa promoter showed H4 hyperacetylation, as demonstrated by the chromatin immunoprecipitation assay. Furthermore, activation of the ERK pathway was involved in VPA-mediated CD61/CD41 expression and in cell adhesion, as demonstrated by using the MEK/ERK inhibitor U0126. In conclusion, the capacity of VPA to commit UT-7 cells to MK differentiation is mediated by its inhibitory action on HDAC and the long-lived activation of ERK1/2.
丙戊酸（VPA）是一种组蛋白去乙酰化酶抑制剂，可在不同细胞系中以细胞特异性方式诱导分化；然而，其对巨核细胞（MK）分化的影响尚未得到研究。我们评估了VPA是否通过GpIIIa基因区域的组蛋白乙酰化和ERK途径的激活来诱导UT-7细胞系中的MK分化。源自巨核母细胞白血病的UT-7细胞用不同浓度的VPA处理，并评估分化标志物的表达以及基因表达谱。流式细胞术、免疫印迹分析和RT-PCR表明，VPA以剂量依赖性方式诱导早期MK标志物GpIIIa（CD61）和GpIIb/IIIa（CD41）的表达。经VPA处理的细胞显示组蛋白H3和H4的高度乙酰化；特别是，发现组蛋白乙酰化与CD61表达相关，因为染色质免疫沉淀试验表明GpIIIa启动子显示H4高度乙酰化。此外，如使用MEK/ERK抑制剂U0126所证明的，ERK途径的激活参与了VPA介导的CD61/CD41表达和细胞黏附。总之，VPA使UT-7细胞向MK分化的能力是由其对HDAC的抑制作用和ERK1/2的长期激活介导的。
