5-氟尿嘧啶半乳糖神经酰胺脂质体的抗耐药作用及部分机制研究

目的研究5氟尿嘧啶半乳糖神经酰胺脂质体(5FuGCL)体外对耐5FuHepG2细胞株的抑制作用并对其抗耐药机制进行探讨。方法在建立耐5Fu的HepG2细胞株模型的基础上,采用MTT法检测5FuGCL对其的抑制作用。另外,通过高效液相法(HPLC)检测细胞内液的药物含量、免疫组化法检测胸苷酸合酶(TS)的表达、化学法检测NO含量等研究其抗耐药作用机制。结果5FuGCL(75,150,300,600,1200μmol·L-1)对耐5Fu的HepG2细胞株有明显的抑制作用,IC50为158.6μmol·L-1,远小于游离5Fu(400.9μmol·L-1);5FuGCL(300μmol·L-1)对耐5Fu的HepG2细胞的抑制作用随时间的延长而增强,其中(24～48h)的抑制作用明显强于相同浓度的游离5Fu。5FuGCL(300μmol·L-1)与相同浓度的游离5Fu比较,能明显增加药物进入HepG2细胞内液的程度;5FuGCL(75,300,1200μmol·L-1)既可明显降低TS的表达,又可显著增加NO的含量,且5FuGCL(300,1200μmol·L-1)与相同浓度的游离5Fu相比,其作用明显增强。结论5FuGCL有明显的抗5Fu耐药作用,这可能是通过增加细胞内液5Fu的含量,抑制TS的表达和增加NO含量实现的。

Inhibitory effect of 5-fluorouracil encapsulated by galactosylceramide liposomes on drug resistance and its mechanisms

Aim To study inhibitory effect of 5-fluorouracil encapsulated by galactosylceramide liposomes (5-Fu-GCL)on 5-Fu-resistent HepG_2 cells and its mechanisms. Methods Inhibitory effect of 5-Fu-GCL on established model of 5-Fu-resistant HepG_2 cells was assessed with MTT assay in vitro. The concentration-time course of 5-Fu-GCL in intracellular fluid was detected with high performance liquid chromatography (HPLC). Thymidylic acid synthase (TS) expression was observed with immunohistochemical method,and NO content was determined with chemical method. Results Obvious inhibitory effects of 5-Fu-GCL (75,150,300,600,1200μmol·L-1) on 5-Fu-resistant HepG_2 cells were observed with IC_ 50 of 158.6 μmol·L-1,far lower than that of free 5-Fu (400.9 μmol·L-1). 5-Fu-GCL (300 μmol·L-1) inhibited 5-Fu-resistant HepG_2 cells in a time-dependent manner,and the inhibitory effect of 5-Fu-GCL was stronger than that of free 5-Fu during 12～48 h. Compared with free 5-Fu,5-Fu-GCL (300 μmol·L-1) increased the content of intracellular fluid in 5-Fu-resistant HepG_2 cells. 5-Fu-GCL(62.5,300,1200 μmol·L-1) not only inhibited the expression of TS,but also increased the production of NO in 5-Fu-resistant HepG_2 cells,and these effects of 5-Fu-GCL(300,1200 μmol·L-1) were stronger than those of free 5-Fu. Conclusion 5-Fu-GCL has inhibitory effect on 5-Fu-resistant HepG_2 cells. The effect may be related to the increased concentration of 5-Fu-GCL in intracellular fluid,inhibited expression of TS and increased production of NO.