Massart C, Gibassier J, Raoul M, Pourquier P, Leclech G, Robert J, Lucas C
Laboratoire de Biochimie A, CHU de Pontchaillou, Rennes, France.
Anticancer Drugs. 1995 Feb;6(1):135-46. doi: 10.1097/00001813-199502000-00016.
Multidrug resistance was investigated in TT cells, a human medullary thyroid carcinoma (MTC) cell line and in normal thyrocytes. MDR1 mRNA was revealed by polymerase chain reaction (PCR) analysis both in normal and neoplastic cells despite the absence of glycoprotein P (Pgp) by immunohistochemistry using JSB-1 monoclonal antibody. Glutathione-S-transferase mRNA was undetectable by Northern blotting in TT cells. Doxorubicin-induced cytotoxicity was evaluated in TT cells with MTT, lacticodehydrogenase (LDH), glutathione (GSH) assays and neutral red uptake. IC50 values obtained for MTT assays were higher than those obtained with the three other tests. Cyclosporin A (CSA) (3 microM), verapamil (10 microM) and S9788 (5 microM) partially reversed the resistance to doxorubicin after a 48 h co-incubation (followed by a 24 h post-incubation for the S9788). Under these conditions, GSH levels were altered by verapamil and S9788, whereas CSA decreased LDH activity. CSA and verapamil had no effect on MTT assay. In conclusion this MTC cell line exhibited over-expression of the MDR1 gene and its resistance to doxorubicin can be partially reversed by CSA, verapamil and S9788.
在人甲状腺髓样癌（MTC）细胞系TT细胞和正常甲状腺细胞中研究了多药耐药性。尽管使用JSB - 1单克隆抗体进行免疫组织化学检测未发现糖蛋白P（Pgp），但通过聚合酶链反应（PCR）分析在正常细胞和肿瘤细胞中均检测到了MDR1 mRNA。通过Northern印迹法在TT细胞中未检测到谷胱甘肽 - S - 转移酶mRNA。使用MTT、乳酸脱氢酶（LDH）、谷胱甘肽（GSH）测定法和中性红摄取法评估了阿霉素诱导的TT细胞毒性。MTT测定获得的IC50值高于其他三种测试获得的值。环孢菌素A（CSA）（3 microM）、维拉帕米（10 microM）和S9788（5 microM）在共孵育48小时后（S9788共孵育后再孵育24小时）部分逆转了对阿霉素的耐药性。在这些条件下，维拉帕米和S9788改变了GSH水平，而CSA降低了LDH活性。CSA和维拉帕米对MTT测定没有影响。总之，这种MTC细胞系表现出MDR1基因的过表达，其对阿霉素的耐药性可被CSA、维拉帕米和S9788部分逆转。
