IMPAIRED DRUG UPTAKE IN METHOTREXATE RESISTANT CRITHIDIA-FASCICULATA WITHOUT CHANGES IN DIHYDROFOLATE-REDUCTASE ACTIVITY OR GENE AMPLIFICATION
IMPAIRED DRUG UPTAKE IN METHOTREXATE RESISTANT CRITHIDIA-FASCICULATA WITHOUT CHANGES IN DIHYDROFOLATE-REDUCTASE ACTIVITY OR GENE AMPLIFICATION
复制标题
DOI：
10.1016/0166-6851(86)90120-9
复制
发表时间：
1986-05-01
影响因子：
1.5
通讯作者：
SIMPSON, L
中科院分区：
文献类型：
--
作者：
DEWES, H;OSTERGAARD, HL;SIMPSON, L
在成分确定的培养基中生长的束状隐翅虫细胞对氨甲喋呤（MTX）敏感，氨甲喋呤是二氢叶酸还原酶（DHFR）的抑制剂。当用2-5 μ M MTX攻击细胞时，细胞分裂在3-4次分裂后停止，细胞变圆并不运动约60小时，在此期间细胞活力降低40%。然后细胞恢复正常形态，细胞分裂恢复。经过这种处理的细胞可以直接转移到高水平的药物（1-2 mM）中。在不存在药物的情况下，耐药表型是稳定的。耐药性与[3 H]MTX的摄取受损相关，在野生型细胞中，[3 H] MTX通过载体介导的过程摄取。没有迹象表明在DNA水平或DHFR活性水平上存在基因扩增，就像耐甲氨蝶呤的大型利什曼原虫一样。几个抗甲氨蝶呤L.显示基因扩增的主要受试者也表现出[3 H]MTX摄取受损。
Crithidia fasciculata cells grown in defined medium are sensitive to methotrexate (MTX), an inhibitor of dihydrofolate reductase (DHFR). When cells are challenged with 2-5 .mu.M MTX, cell division ceases after 3-4 divisions and the cells become rounded and immotile for approximately 60 h, with a 40% decrease in cell viability occurring during this period. The cells then recover normal morphology and cell division resumes. Cells which undergo this treatment can be transferred directly into high levels of the drug (1-2 mM). The resistance phenotype is stable in the absence of drug. Resistance correlates with impaired uptake of [3H]MTX, which in wild-type cells is taken up by a carrier-mediated process. There is no indication of gene amplification at the DNA level or at the level of DHFR activity, as occurs in the case of MTX-resistant Leishmania major. Several lines of MTX-resistant L. major which show gene amplification also exhibit impaired uptake of [3H]MTX.