Inhibitory effect of 5-fluorouracil encapsulated by galactosylceramide liposomes on drug resistance and its mechanisms / 中国药理学通报

ABSTRACT

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 (75,150,300,600,1200?mol?L-1) on 5-Fu-resistant HepG_2 cells were observed with IC_ 50 of 158.6 ?mol?L-1,far lower than that of free 5-Fu (400.9 ?mol?L-1). 5-Fu-GCL (300 ?mol?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 ?mol?L-1) increased the content of intracellular fluid in 5-Fu-resistant HepG_2 cells. 5-Fu-GCL(62.5,300,1200 ?mol?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 ?mol?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.