赛赓啶对 KBV200细胞多药抗性的逆转作用

研究赛赓啶对KB_V200细胞多药抗性的逆转作用及逆转机制。在KB_V200细胞,采用MTT法,测出赛赓啶对长春新碱、阿霉素和鬼臼乙叉甙耐药的逆转系数分别为5.5,2.0和1.9,而对5-氟尿嘧啶、美法仑的细胞毒性作用无明显影响,表明赛赓啶为多药抗性逆转剂。荧光分光光度法测定表明,赛赓啶可使KB_V200细胞内阿霉素蓄积量增加。流式细胞荧光测定显示赛赓啶可增加罗丹明123的蓄积并减慢其外排。免疫细胞化学及狭缝杂交表明赛赓啶不影响KB_V200细胞的P-糖蛋白染色深度和 mdr1 RNA 表达水平。以上结果提示赛赓啶的多药抗性逆转机制是抑制P-糖蛋白泵的功能。

REVERSAL OF MULTIDRUG RESISTANCE BY CYPROHEPTADINE IN KB V200 CELLS

The cyproheptadine (CYP) reversal of multidrug resistance (MDR) and its mechanism in KBV200 cell line were studies. MTT assay showed that CYP 15.0 mumol.L-1 could reverse vincristine, adriamycin (ADR) and etoposide resistance in KBV200 cells by a factor of 5.5, 2.0 and 1.9, respectively. CYP appeared to have no influence on the cytotoxicity of 5-fluorouracil (5-FU) and melphalan (MEL) in the cells. These results indicate that CYP is a MDR reversing agent. CYP 15.0 mumol.L-1 increased the ADR accumulation in KBV200 cells from 0.68 +/- 0.03 microgram/10(6) cells to 1.36 +/- 0.08 micrograms/10(6) cells (P < 0.01). CYP 15.0 mumol.L-1 was shown to obviously increase rhodamine 123 (R123) accumulation in and decrease its efflux from the cells. There was no change in PGP dying intensity under immunocytochemical assay and in mdr1 RNA level through slot blot analysis in the KBV200 cells exposed continuously to CYP 15.0 mumol.L-1 for 72 h. These results suggest that CYP acts by inhibiting the pumping function of PGP.