Jiang X R, Macey M G, Collins P W, Newland A C
Department of Haematology, London Hospital Medical College, London.
Br J Haematol. 1994 Mar;86(3):547-54. doi: 10.1111/j.1365-2141.1994.tb04785.x.
The effects of cyclosporin A (CSA) and cellular energy depletion on daunorubicin (DAU) transport kinetics were investigated in a human erythroid leukaemia cell line K562 c1.6 selected for resistance to daunorubicin. K562 c1.6/DAU resistant cells displayed high levels of P-glycoprotein and a high level of multidrug resistance against several antitumour drugs. The resistance factors of K562 c1.6/DAU cells to DAU, doxorubicin, vinblastine and etoposide were 106, 114, 85 and 13 respectively. A 1.6-fold decrease (P < 0.01, n = 8) in DAU accumulation and a 4-fold increase (P < 0.001, n = 8) in DAU efflux were shown in the resistant cells when compared to K562 c1.6 drug-sensitive parental cells. K562 c1.6/DAU cells were also shown to reach a DAU saturation level (SL) 8-fold faster (P < 0.001, n = 8) than the parental cells. Addition of CSA to the resistant cells led to a dose-dependent increase in cellular DAU retention, while no such effect was observed in the sensitive cells by the introduction of CSA. Resistance to the antitumour drugs could be reduced to various extents by CSA. The patterns of changes and modulations of DAU transport kinetics, as well as chemosensitivity in K562 c1.6/DAU cells were found to be similar to a vinblastine-resistant leukaemia cell line CEM/VLB100. However, K562 c1.6/DAU cells were more resistant to DAU, doxorubicin and etoposide than the CEM/VLB100 cells. An increase in DAU accumulation, intracellular SL and the time to reach 90% saturation level (SL90), and a decrease in DAU efflux in the resistant but not the sensitive cells were found in response to ATP depletion by sodium azide. These effects could be completely reversed by addition of glucose. Our results suggest that the presence of an energy-dependent effluxing mechanism responsible for the decreased drug accumulation and enhanced drug efflux may make a major contribution to the mechanism of resistance in K562 c1.6/DAU resistant cells.
在一株对柔红霉素具有抗性的人红白血病细胞系K562 c1.6中，研究了环孢菌素A（CSA）和细胞能量耗竭对柔红霉素（DAU）转运动力学的影响。K562 c1.6/DAU抗性细胞表现出高水平的P-糖蛋白以及对多种抗肿瘤药物的高水平多药耐药性。K562 c1.6/DAU细胞对DAU、阿霉素、长春碱和依托泊苷的耐药因子分别为106、114、85和13。与K562 c1.6药物敏感的亲本细胞相比，抗性细胞中DAU蓄积降低了1.6倍（P<0.01，n = 8），DAU流出增加了4倍（P<0.001，n = 8）。还显示K562 c1.6/DAU细胞达到DAU饱和水平（SL）的速度比亲本细胞快8倍（P<0.001，n = 8）。向抗性细胞中添加CSA导致细胞内DAU滞留呈剂量依赖性增加，而在敏感细胞中引入CSA未观察到这种效应。CSA可在不同程度上降低对抗肿瘤药物的抗性。发现K562 c1.6/DAU细胞中DAU转运动力学的变化和调节模式以及化学敏感性与长春碱抗性白血病细胞系CEM/VLB100相似。然而，K562 c1.6/DAU细胞对DAU、阿霉素和依托泊苷的抗性比CEM/VLB100细胞更强。发现叠氮化钠导致ATP耗竭后，抗性细胞而非敏感细胞中DAU蓄积增加、细胞内SL和达到90%饱和水平（SL90）的时间增加，以及DAU流出减少。添加葡萄糖可使这些效应完全逆转。我们的结果表明，存在一种能量依赖性流出机制，其导致药物蓄积减少和药物流出增强，这可能是K562 c1.6/DAU抗性细胞耐药机制的主要原因。
