丙戊酸抗裸鼠Kasumi-1细胞移植瘤血管新生的作用研究

本研究旨在探讨组蛋白去乙酰化酶抑制剂丙戊酸（VPA）体内、体外抑制急性髓系白血病血管新生及其作用机制。用不同浓度的VPA处理人t（8；21）急性白血病细胞株Kasumi-1细胞3d后用RT-PCR及Westernblot分析细胞Angl、Ang2mRNA及蛋白水平的变化；建立Kasumi-1细胞裸鼠移植瘤模型，采用RT-PCR、Westernblot的方法分析对照组和VPA治疗组瘤组织ang]、Ang2、VEGFmRNA及蛋白水平的变化，免疫组织化学的方法分析瘤组织CD34及Angl、An蛇蛋白水平的改变。结果表明，VPAl-3mmol／L处理3d能够下调Kasumi-1细胞AnglmRNA（3mmol／L组0．040±0．008，对照组O．360±0．116）、Ang2mRNA（3mmol／L组0．146±0．038，对照组0．540±0．049）及蛋白的相对表达，呈浓度依赖性；VPA500mg／kg，ip，处理14d能够明显降低裸鼠瘤组织Angl、Ang2、VEGFmRNA及蛋白的相对表达（P〈0．01），并能明显减少荷Kasumi-1细胞裸鼠移植瘤微血管密度（8．470±0．3001352．600±O．200）。结论：VPA可能通过调节血管生成素及VEGF的表达，阻碍白血病的血管新生，从而抑制白血病细胞浸润、迁移。

Effect of Valproic Acid against Angiogenesis of Kasumi-1 Xenograft Tumor in Nude Mice

This study was aimed to investigate the effect of valproic acid（ VPA）, a histone deacetylase inhibitor, on angiogenesis of acute myeloid leukemia in vivo and vitro, and to explore its molecular mechanism. Human t（8 ;21 ） AML cell line Kasumi-1 cells were treated with VPA at different concentration for 3 d, the mRNA and protein expression levels of Angl and Ang2 were determined by semi-quantitative RT-PCR and Western blot respectively. Nude mice model with xenograft Kasumi-1 tumor was established by subcutaneous inoculation of Kasumi-1 cells. The CD34, Angl and Ang2 protein levels were analyzed by immunohistochemistry method. The mRNA and protein expression levels of Angl, Ang2 and VEGF were determined by semi-quantitative RT-PCR and Western blot. The results showed that in vitro, VPA at 3 mmol/L downregulated the Ang mRNA relative expression level for Angl from 0.360 ±0. 116 to 0.040 ±0.008, Ang2 from 0.540 ±0.049 to 0. 146 ±0.038. The animal experiment further verified that VPA 500 mg/kg, ip, for 14 d, reduced the relative expression of Angl ,Ang2 and VEGF mRNA and proteins in Kasumi-1 tumor of nude mice, and reduced microvascullar density in xenograft tumor of nude mice （8.470± 0.300 vs 2.600 ±0.200）. It is concluded that VPA significantly inhibits tumor angiogenesis through the regulation of angiopoietins, thereby inhibits the proliferation and metastasis of leukemia cells.