双靶向5-氟尿嘧啶纳米粒对小鼠原位肝癌模型的抑制作用

Inhibitory effects of liver-targeting dual-ligand-modified 5-fluorouracil nanoparticles in murine liver cancer

目的观察双靶向5-氟尿嘧啶(5-FU)纳米粒的体内靶向性,其对小鼠原位肝癌模型的抑制作用及其可能的机制。方法半乳糖(LA)和甘草次酸(GA)这两个配体与壳聚糖(CTS)成功合成乳糖酸化甘草次酸壳聚糖(GCGA),并将GCGA和5-FU合成GCGA/5-FU纳米粒。建立小鼠原位肝癌移植模型,将实验模型分对照组(Control组),GCGA组,5-FU组,CTS/5-FU组,GA-CTS/5-FU组和GCGA/5-FU组,除Control组采用生理盐水静脉注射外,其余各组均采用对应药物尾静脉注射,剂量均为200μl。观察GCGA/5-FU纳米粒体内靶向作用及其对小鼠原位肝癌模型的抑制作用。结果 GCGA/5-FU纳米粒的粒径为239.9 nm,多分散指数为0.040,Zeta电势为+21.2 m V,载药量为3.90%。肝脏组织中的5-FU浓度浓度由高到底依次为GCGA/5-FU组,GA-CTS/5-FU组,CTS/5-FU组和5-FU组;GCGA/5-FU纳米粒在体内分布表明,肝脏的5-FU浓度最高,具有明显的肝脏靶向性。GCGA/5-FU纳米粒具有明显抑制小鼠原位肝癌抑制模型的作用,延长小鼠的生存期,并且发现GCGA纳米粒具有缓解5-FU的毒副作用,GCGA纳米粒具有促进5-FU抑制肿瘤生长作用,与缓解5-FU对机体免疫抑制有关,主要通过缓解机体的Treg细胞的比率升高,缓解CTL和NK细胞的比率降低和促进活化,同时缓解机体的IL-2和IFN-γ水平的下降有关。结论GCGA/5-FU纳米粒具有明显的肝脏靶向性,对小鼠原位肝癌模型具有明显的抑制作用,具有提高机体的细胞免疫功能的作用。

Objective To observe the targeted therapy of liver-targeting dual-ligand-modified 5-fluorouracil nanoparticles（ GCGA/5-FU） in murine liver cancer in vivo,the inhibitory effects of orthotopic liver cancer and its mechanism. Methods The dual-ligand modified chitosan（ GCGA） nanomaterial were synthesized using lactose acid（ LA）,glycyrrhetinic acid（ GA） and chitosan（ CTS） to target for liver,since the LA and GA could bind to the receptors on liver cell surface. The GCGA /5-FU nanoparticles were then synthesized by conjugating 5-fluorouracil（ 5-FU） onto the GCGA nanomaterial. The orthotopic liver cancer in mice were established,and the model mice were divided into control,GCGA,5-FU,CTS /5-FU,GA-CTS /5-FU and GCGA /5-FU groups. The corresponding therapeutic strategies were used in each groups.The liver-targeted and inhibitory effects of GCGA /5-FU were observed. Results The prepared GCGA /5-FU nanoparticles had a mean particle size of 239. 9 nm,a polydispersity index of 0. 040,a zeta potential of ＋ 21. 2 m V,and a drug loading of 3. 90%. The concentrations of 5-FU in liver tissue from high to bottom in turn were GCGA /5-FU group,GA-CTS /5-FU group,CTS /5-FU group and 5-FU group. The inhibitory effects of GCGA /5-FU on tumor cells were targeted for liver,and were time-and dose-dependent. GCGA nanomaterial could significantly prolong the efficacy of 5-FU to tumor cells,and can alleviate the resistance of tumor cells to 5-FU. The in vivo distribution of GCGA /5-FU nanoparticles showed that 5-FU was most concentrated in the liver,indicating that the GCGA nanoparticles were liver-targeted. GCGA /5-FU nanoparticles significantly suppressed tumor growth in orthotopic liver transplantation mouse model,and improved mouse survival. We also found that GCGA nanoparticles enhanced the inhibitory effects of 5-FU by attenuating the toxicity of 5-FU. This may because that GCGA could alleviate 5-FU-induced immune suppression by reducing Treg ratio,inducing CTL and NK cell proliferation and activation,and by up-regulating IL-2 and IFN-γ level. Conclusion The GCGA /5-FU nanoparticles are significantly liver-targeted,and it has significantly inhibitory in orthotopic liver transplantation mouse model and can improve the body＇s cellular immune function.