Agents that reverse multidrug resistance, tamoxifen, verapamil, and cyclosporin A, block glycosphingolipid metabolism by inhibiting ceramide glycosylation in human cancer cells
Agents that reverse multidrug resistance, tamoxifen, verapamil, and cyclosporin A, block glycosphingolipid metabolism by inhibiting ceramide glycosylation in human cancer cells
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DOI：
10.1074/jbc.272.3.1682
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发表时间：
1997-01-17
影响因子：
4.8
通讯作者：
Cabot, MC
中科院分区：
文献类型：
--
作者：
Lavie, Y;Cao, HT;Cabot, MC
我们先前已经表明，多药耐药癌细胞显示葡糖神经酰胺水平升高（Lavie，Y.，曹，H.，Bursten，S. L.，朱利亚诺，A. E、和Cabot，M. C.（1996）J.Biol.Chem.271，19530-19536）。在这项研究中，我们使用了多药耐药的人乳腺癌细胞。细胞系MCF-7-阿霉素抗性（AdrR），其与亲本MCF-7野生型（药物敏感性）细胞系相比表现出葡糖神经酰胺的显著积累，以确定糖脂与多药耐药（MDR）之间的关系。本文显示，临床相关浓度的他莫昔芬、维拉帕米和环孢菌素A（所有MDR的规避物）显著降低MCF-7-AdrR细胞中的葡糖神经酰胺水平（IC 50值分别为1.0、0.8和2.3 μ M）。在完整的细胞中，他莫昔芬抑制鞘糖脂合成的神经酰胺糖基化的步骤。在葡萄糖神经酰胺合酶的无细胞测定中，他莫昔芬（与神经酰胺的摩尔比为1：10）抑制葡萄糖神经酰胺形成近50%。在细胞培养中，他莫昔芬对葡萄糖神经酰胺合成的抑制与其使MCF-7-AdrR细胞对阿霉素毒性敏感的能力相关。此外，用葡糖神经酰胺合成抑制剂1-苯基-2-棕榈酰氨基-3-吗啉代-1-丙醇处理细胞，同样使MCF-7-AdrR细胞对阿霉素敏感。可以得出结论，高细胞水平的葡萄糖神经酰胺与MDR相关，糖脂是MDR逆转剂，如他莫昔芬的作用的目标。这些数据接受了耐药性现象与细胞代谢神经酰胺的能力一致的观点。
We have previously shown that multidrug-resistant cancer cells display elevated levels of glucosylceramide (Lavie, Y., Cao, H., Bursten, S. L., Giuliano, A. E., and Cabot, M. C. (1996) J. Biol. Chem. 271, 19530-19536). In this study we used the multidrug-resistant human breast cancer cell. line MCF-7-Adriamycin-resistant (AdrR), which exhibits marked accumulation of glucosylceramide compared with the parental MCF-7 wild type (drug-sensitive) cell line, to define the relationship between glycolipids and multidrug resistance (MDR). Herein it is shown that clinically relevant concentrations of tamoxifen, verapamil, and cyclosporin A, all circumventors of MDR, markedly decrease glucosylceramide levels in MCF-7-AdrR cells (IC50 values, 1.0, 0.8, and 2.3 mu M, respectively). In intact cells, tamoxifen inhibited glycosphingolipid synthesis at the step of ceramide glycosylation. In cell-free assays for glucosylceramide synthase, tamoxifen (1:10 molar ratio with ceramide) inhibited glucosylceramide formation by nearly 50%. In cell cultures, inhibition of glucosylceramide synthesis by tamoxifen is correlated with its ability to sensitize MCF-7-AdrR cells to Adriamycin toxicity. Moreover, treatment of cells with 1-phenyl-2-palnitoylamino-3-morpholino-1-propanol, an inhibitor of glucosylceramide synthesis, likewise sensitized MCF-7-AdrR cells to Adriamycin. It is concluded that high cellular levels of glucosylceramide are correlated with MDR, and that glycolipids are a target for the action of MDR-reversing agents such as tamoxifen. The data entertain the notion that drug resistance phenomena are aligned with cell capacity to metabolize ceramide.