黄芩苷对高致瘤HL-60细胞裸鼠移植瘤模型的体内抑瘤作用和机制探讨

Effects of Baicalin on HL-60 Cell Xenografts in Nude Mice and Its Mechanism

本研究旨在探讨黄芩苷对高致瘤人白血病HL-60细胞裸鼠异种移植瘤的体内抑瘤作用及其作用机制。制备高致瘤HL-60细胞裸鼠异种移植瘤模型,将荷瘤裸鼠随机分为6组:阴性对照组(注射5%NaHCO3),黄芩苷25、50和100 mg/kg剂量组,联合用药组(黄芩苷50 mg/kg+VP16 2 mg/kg)和VP16 4 mg/kg阳性对照组,每组10只裸鼠。采用腹腔注射方式给药,14 d后每组处死5只裸鼠,对剥取的瘤块称重计算抑瘤率;通过电子显微镜观察瘤组织超微结构,病理组织学观察裸鼠各主要脏器结构改变,瘤块组织蛋白检测信号转导通路指标。观察裸鼠生存时间。结果表明,黄芩苷可抑制裸鼠HL-60细胞皮下移植瘤的生长,呈剂量依赖性。瘤组织病理组织学和透射电子显微镜检查结果显示,黄芩苷组和联合用药组的肿瘤坏死和细胞凋亡现象较阴性对照组多见。黄芩苷可能通过抑制Akt活性,下调p-Akt、mTOR和p-mTOR的表达来抑制裸鼠异种移植瘤的增长。联合用药组裸鼠中位生存时间明显长于阴性对照组(P<0.05)。结论:黄芩苷可抑制高致瘤HL-60细胞裸鼠异种移植瘤的生长,诱导瘤组织中HL-60细胞的凋亡,其机制之一可能与抑制Akt活性并下调PI3K/Akt/mTOR信号通路有关;黄芩苷与VP16联用可明显提高荷瘤裸鼠的中位生存期,具有协同抗高致瘤HL-60细胞裸鼠异种移植瘤的作用。

This study was aimed to investigate the effects of baicalin on HL-60 cell xenografts in nude mice in vivo and explore its mechanism.Xenograft tumor model of HL-60 cells in nude mice was established,which was divided randomly into 6 groups： negative control group（injection of 5% NaHCO3）,25,50 and 100 mg/kg baicalin groups,combination group（50 mg/kg baicalin＋2 mg/kg VP16） and positive control group（VP16 4 mg/kg）.The nude mice with HL-60 cell xenografts were treated with drugs via intraperitoneal injection daily.After treatment for 14 days average weigh and inhibitory rate of transplanted tumor stripped from 5 nude mice in each group were calculated,and the ultrastructure change of xenografts cells were tested by transmission electron microscopy.Histopathologic examination was used to observed the change of main organs in nude mice.The expression of signaling molecular PI3K/Akt proteins extracted from xenografts was detected by Western blot.The effects of baicalin on overall survival time in nude mice with HL-60 cell xenografts were evaluated.The results showed that baicalin could inhibit the growth of transplanted tumors in dose-dependent manner.There were more necrotic and apoptotic cells in mice of baicalin-treated groups and combination group than that in mice of negative control group.Baicalin could inhibit the proliferation of HL-60 cells in vivo by down-regulating the PI3K/Akt/mTOR signal pathway,where the expressions of p-Akt,mTOR and p-mTOR proteins decreased compared with negative control group,and no significant difference of Akt expression was found between different groups.Compared with negative control group,the median survival time of mice in combination group was more prolongated（P 0.05）.It is concluded that baicalin can inhibit growth and induce apoptosis of HL-60 cell xenografts in nude mice,and prolong median survival time of nude mice.The possible mechanisms may be related to inhibition of Akt activity and down-regulation of the PI3K / Akt / mTOR signal pathway.The combination of baicalin and VP16 shows a synergistic effect on inhibiting growth of HL-60 cell xenografts in nude mice.