Differential effect of the calmodulin inhibitor trifluoperazine in modulating cellular accumulation, retention and cytotoxicity of doxorubicin in progressively doxorubicin-resistant L1210 mouse leukemia cells. Lack of correlation between cellular doxorubi
Differential effect of the calmodulin inhibitor trifluoperazine in modulating cellular accumulation, retention and cytotoxicity of doxorubicin in progressively doxorubicin-resistant L1210 mouse leukemia cells. Lack of correlation between cellular doxorubi
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钙调蛋白抑制剂三氟拉嗪在调节阿霉素逐渐耐药的 L1210 小鼠白血病细胞中阿霉素的细胞积累、保留和细胞毒性方面的不同作用。
DOI：
10.1016/0006-2952(88)90716-2
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发表时间：
1988
影响因子：
5.8
通讯作者：
Grabowski,D
中科院分区：
文献类型：
--
作者：
Ganapathi,R;Grabowski,D
钙调素抑制剂可以有效地增强阿霉素（DOX）在DOX耐药细胞中的细胞毒性作用，可能是通过提高药物的细胞水平。在本研究中，L1210小鼠白血病细胞适应于在0.025 ~ 0.25 μg/ml DOX存在下的体外生长，鉴定为L1210/DOX0.025、L1210/DOX0.05、L1210/DOX0.1和L1210/DOX0.25，与亲本敏感细胞（L1210/S）相比，分别具有约5倍、10倍、20倍和40倍的DOX抗性。通过软琼脂集落实验和3小时的药物暴露，在无5 μM三氟拉嗪（TFP）和无细胞毒性浓度5 μM三氟拉嗪（TFP）存在的情况下，DOX在逐渐耐药（5- 40倍）L1210细胞中的ic50浓度分别为0.25 ~ 2.0 μg/ml和0.08 ~ 0.25 μg/ml。此外，根据观察到的卵细胞毒性反应，在L1210/ DOX0.025、L1210/DOX0.05、L1210/DOX0.1和L1210/DOX0.25耐药亚系中，5 μM TFP存在下DOX的ic50浓度分别比不含5 μM TFP的DOX低2.5倍、4倍、6.7倍和8倍。与此相反，加或不加5 μM TFP时，L1210/S细胞中DOX的ic50约为0.05 μg/ml。与类似处理的L1210/S细胞相比，渐进式耐药L1210亚组的DOX细胞积累降低了15-50%。然而，在5 μM TFP存在下，与L1210/DOX0.05和L1210/DOX0.1而非L1210/DOX0.25细胞中DOX的细胞积累与L1210/S细胞相当。在同样处理的L1210/S、L1210/DOX0.05和L1210/DOX0.1细胞中，不存在5 μM TFP时DOX的细胞保留率与存在5 μM TFP时相似，并且只有在L1210/DOX0.25细胞中，DOX的保留率比不存在5 μM TFP时降低2倍。在5 μM TFP存在下，DOX的浓度为50时，虽然在1 ~ 20 μM TFP范围内DOX的细胞积累是浓度依赖性的，但在1 ~ 5 μM TFP范围内DOX的细胞毒性增强是剂量依赖性的，而在5 ~ 20 μM TFP范围内则不是。在DOX单独或DOX加5 μM TFP浓度下处理3小时的细胞中，抗性细胞的DOX积累量分别比敏感细胞高7- 14倍和2.5- 3.5倍。此外，在不存在5 μM TFP或不存在5 μM TFP的情况下，以ic50剂量的DOX治疗3小时后，耐药细胞的药物保留率分别比敏感细胞高4至6倍和1.5倍。本研究结果表明：(1)TFP对DOX细胞毒性的影响依赖于获得性耐药水平；(2)与敏感细胞相比，抗性亚细胞在不存在TFP的情况下需要更高的细胞水平的DOX才能达到相同的细胞毒性；(3)在敏感和耐药亚系中积累或保留期间DOX的细胞水平差异似乎与耐药表达的大小无关。
Calmodulin inhibitors are effective in enhancing cytotoxic effects of doxorubicin (DOX) in DOX-resistant cells, possibly by enhancing cellular levels of drug. In the present study, L1210 mouse leukemia cells adapted to growin vitro, in the presence of 0.025 to 0.25 μg/ml DOX, and identified as L1210/DOX0.025, L1210/DOX0.05, L1210/DOX0.1, and L1210/DOX0.25 were approximately 5-, 10-, 20-, and 40-fold DOX resistant, respectively, compared to parent-sensitive cells (L1210/S). Using a soft agar colony assay and 3-hr drug exposure, theic50concentration of DOX in the progressively DOX-resistant (5- to 40-fold) L1210 cells ranged from 0.25 to 2.0 μg/ml and from 0.08 to 0.25 μg/ml in the absence and presence of a non-cytotoxic concentration of 5 μM trifluoperazine (TFP) respectively. Further, based on the observedin vitrocytotoxic response, theic50concentration of DOX in the presence of 5 μM TFP was 2.5-, 4-, 6.7- and 8-fold lower than DOX without 5 μM TFP in the L1210/ DOX0.025, L1210/DOX0.05, L1210/DOX0.1, and L1210/DOX0.25 resistant sublines respectively. In contrast, theic50of DOX in L1210/S cells was approximately 0.05 μg/ml with or without 5 μM TFP. Cellular accumulation of DOX was 15–50% lower in the progressively resistant L1210 sublines compared to similarly treated L1210/S cells. However, in the presence of 5 μM TFP, cellular accumulation of DOX in the L1210/DOX0.05 and L1210/DOX0.1 but not L1210/DOX0.25 was comparable to the L1210/S cells. Cellular retention of DOX in the absence or presence of 5 μM TFP was comparable in similarly treated L1210/S, L1210/DOX0.05 and L1210/DOX0.1 cells, and a 2-fold reduction in the retention of DOX in the absence versus the presence of 5 μM TFP was apparent only in L1210/DOX0.25 cells. At theic50of DOX in the presence of 5 μM TFP, although cellular accumulation of DOX was concentration dependent over the range of 1–20 μM TFP, enhancement in cytotoxicity of DOX was dose dependent at 1–5 μM TFP but not 5–20 μM TFP. In cells treated for 3 hr at theic50concentration of DOX alone or DOX plus 5 μM TFP, cellular accumulation of DOX was 7- to 14-fold and 2.5- to 3.5-fold higher, respectively, in resistant than in sensitive cells. Additionally, following treatment for 3hr at theic50dose of DOX in the absence or presence of 5 μM TFP, drug retention at 3 hr was 4- to 6-fold and 1.5-fold higher, respectively, in the resistant versus sensitive cells. Results from this study demonstrate that: (1) the effect of TFP on DOX cytotoxicity was dependent on the level of acquired resistance; (2) in contrast to sensitive cells, the resistant sublines required much higher cellular levels of DOX in the absence versus the presence of TFP to achieve equivalent cytotoxicity; and (3) differences in cellular levels of DOX during accumulation or retention in sensitive versus resistant sublines did not appear to correlate with the magnitude in expression of resistance.