丙戊酸抗裸鼠Kasumi-1细胞移植瘤血管新生的作用研究

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

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3 d后用RT-PCR及Western blot分析细胞Ang1、Ang2 mRNA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、Western blot的方法分析对照组和VPA治疗组瘤组织Ang1、Ang2、VEGF mRNA及蛋白水平的变化,免疫组织化学的方法分析瘤组织CD34及Ang1、Ang2蛋白水平的改变。结果表明,VPA 1-3 mmol/L处理3 d能够下调Kasumi-1细胞Ang1 mRNA(3 mmol/L组0.040±0.008,对照组0.360±0.116)、Ang2 mRNA(3 mmol/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;VPA 500 mg/kg,ip,处理14 d能够明显降低裸鼠瘤组织Ang1、Ang2、VEGF mRNA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±0.300vs 2.600±0.200)。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。

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.