苯丁酸钠联合5-氮杂脱氧胞苷抑制Kasumi-1细胞裸鼠移植瘤的生长

Combination of phenylbutyrate and 5-Aza2’-deoxycytidine inhibits human Kasumi-1 xenograft tumor growth in nude mice

目的 探讨组蛋白脱乙酰化酶 (HDAC)抑制剂苯丁酸钠 (PB)联合 5 氮杂脱氧胞苷 (5 Aza CdR)对t(8;2 1)急性髓系白血病裸鼠移植瘤模型的抑瘤活性与作用机制。方法 用Kasumi 1细胞皮下接种的方法建立t(8;2 1)急性髓系白血病裸鼠移植瘤模型 ;观察裸鼠的致瘤潜伏期、PB预处理Kasumi 1细胞的致瘤性改变 ,以及PB和 5 Aza CdR腹腔注射对移植瘤生长的抑制作用。流式细胞术检测细胞分化抗原和细胞周期 ,末端脱氧核糖核酸转移酶介导的dUTP原位缺口末端标记 (TUNEL)检测瘤组织凋亡 ,免疫组织化学染色检测血管新生。结果 切脾和不切脾裸鼠接种Kasumi 1细胞后致瘤潜伏期分别为 17～ 2 3d和 4 0～ 5 0d ,瘤细胞不转移 ,仍检测出t(8;2 1)和AML1 ETO融合基因。接种PB预处理Kasumi 1细胞的裸鼠未见成瘤。PB、5 Aza CdR单独或联合裸鼠体内用药后 ,移植瘤生长抑制率分别为 4 9.0 7%、2 5 .6 9%和 87.4 6 % (P <0 .0 5 ) ,凋亡细胞指数分别为 (2 .2 5± 0 .85 ) %、(1.32± 0 .6 8) %和 (5 .4 1± 1.5 6 ) % (P <0 .0 5 ) ,微血管密度 (MVD)分别为 2 1.6 9± 6 .2 5 ,2 8.34± 4 .2 4和 9.4 8± 3.2 1(P <0 .0 1) ,与对照组相比有显著性差异 (P值均 <0 .0 5 )。PB腹腔注射后移植瘤细胞CD11b、CD13表达增高 [(12 .0

Objective To investigate the tumor suppression efficacy of histone deacetylase inhibitor, phenylbutyrate (PB), in combination with DNA methylation inhibitor 5 Aza 2 deoxycytidine(5 Aza CdR) in the treatment of Kasumi 1 xenograft tumor in nude mice and its mechanism. Methods The nude mice model of Kasumi 1 xenograft tumor was established by subcutaneous inoculation. Latency of tumor formation, the ability of Kasumi 1 cells pre treated with PB to form the xenograft tumor, and the tumor suppression activity of PB and 5 Aza CdR by intraperitoneal injection in xenografted mice model were detected. Cell differentiation and cell cycle parameters of the tumor cells were analyzed by flow cytometry analysis, apoptosis by TUNEL in situ hybridization, and tumor microvessel density (MVD) by immunohistochemistry study. Results The latency of tumor formation in mice with or without previous lienectomy was 17～23 and 40～50 days, respectively. Tumor cells xenografted could not be found in other tissues than in inoculation area, and still harbored the specific t(8;21) and AML1 ETO fusion gene. When the xenografted mice models treated with PB, 5 Aza CdR, or both, the tumor growth inhibition rates were 49.07%, 25.69% and 87.46%(P<0.05), the apoptosis indexes (AI) of tumor cells were (2.25±0.85)%, (1.32±0.68)%, and (5.41±1.56)%( P<0.05 ), and the microvessel densities (MVD) were 21.69±6.25,28.34±4.24 and 9.48±3.21( P<0.01 ),respectively. All the data above were significantly different from that in control(P<0.05). The expression of CD11b and CD13 antigen of the tumor cells was increased in xenografted mice model treated with PB when compared with the control\[(12.08±1.02)% and (54.91±2.72)%\], respectively(P< 0.01 ), and tumor cells showed a cell cycle arrest with increased G 0/G 1 phase cells and decreased S phase cells. Conclusion PB inhibited the growth of Kasumi 1 xenograft tumor by inducing tumor cell apoptosis and differentiation, and suppressing its angiogenesis in vivo. 5 Aza CdR could significantly enhance the antitumor activity of PB.