Decorti G, Peloso I, Favarin D, Klugmann F B, Candussio L, Crivellato E, Mallardi F, Baldini L
Department of Biomedical Sciences, University of Trieste, Italy.
J Pharmacol Exp Ther. 1998 Jul;286(1):525-30.
The characteristics of doxorubicin handling have been studied in the cultured kidney epithelial cell line LLC-PK1, which has structure and function similar to those of renal tubular cells and expresses P-glycoprotein. The uptake of doxorubicin by LLC-PK1 cells was time dependent, reaching a steady state at about 4 hr, and reduced at low temperature; the initial uptake was saturable. The efflux of doxorubicin from LLC-PK1 cells was also temperature dependent but, even at 37 degrees C, a significant percentage of the drug remained associated with the cells after 180 min, which suggests a strong cellular binding, and the fluorescence microscopy revealed that the drug was concentrated in intracellular organelles. Substances that are substrates for P-glycoprotein, such as verapamil, vinblastine, vincristine and quinidine, significantly increased doxorubicin concentrations in LLC-PK1 cells. Similar results were obtained with the metabolic inhibitors sodium metavanadate and 2,4-dinitrophenol. On the other hand, the uptake was not affected by the classic organic cation transport drugs cimetidine, decynium 22 or decynium 24, nor by the organic anion drug probenecid. These results indicate that, in LLC-PK1 cells, doxorubicin enters by passive diffusion, is trapped in intracellular organelles and then is extruded from cells by a mechanism that probably involves P-glycoprotein. On the contrary, substances that interfere with the renal organic cation or anion secretory system have no effect on doxorubicin net accumulation in these cells.
已在培养的肾上皮细胞系LLC-PK1中研究了阿霉素的处理特性，该细胞系具有与肾小管细胞相似的结构和功能，并表达P-糖蛋白。LLC-PK1细胞对阿霉素的摄取呈时间依赖性，在约4小时达到稳态，且在低温下降低；初始摄取是可饱和的。阿霉素从LLC-PK1细胞中的流出也与温度有关，但即使在37℃时，180分钟后仍有相当比例的药物与细胞结合，这表明细胞结合力很强，荧光显微镜显示药物集中在细胞内细胞器中。作为P-糖蛋白底物的物质，如维拉帕米、长春碱、长春新碱和奎尼丁，可显著提高LLC-PK1细胞中阿霉素的浓度。代谢抑制剂偏钒酸钠和2,4-二硝基苯酚也得到了类似的结果。另一方面，摄取不受经典有机阳离子转运药物西咪替丁、癸鎓22或癸鎓24的影响，也不受有机阴离子药物丙磺舒的影响。这些结果表明，在LLC-PK1细胞中，阿霉素通过被动扩散进入细胞，被困在细胞内细胞器中，然后通过一种可能涉及P-糖蛋白的机制从细胞中排出。相反，干扰肾脏有机阳离子或阴离子分泌系统的物质对这些细胞中阿霉素的净积累没有影响。
