Arita I, Tatsumi K, Tachibana A, Toyoda M, Takebe H
Department of Molecular Oncology, Faculty of Medicine, Kyoto University, Japan.
Mutat Res. 1988 Jul;208(3-4):167-72. doi: 10.1016/0165-7992(88)90055-3.
Three lymphoblastoid cell lines (LCLs) had extremely low activities of O6-alkylguanine-DNA alkyltransferase (O6-AGT), and were classified as Mex-. They were highly sensitive to cell killing by 1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)-3-nitrosoure a hydrochloride (ACNU), whereas NMO2, a Mex+ LCL with a high O6-AGT activity, was resistant to the agent. Small fractions of these Mex- LCLs survived the treatment with 10 micrograms/ml of ACNU for 24 h, and the surviving cells were found to be resistant to subsequent treatments with the agent. In addition, they contained O6-AGT activities comparable to that of NMO2 and were therefore regarded as Mex+. These results suggest that the Mex- phenotype in LCLs is unstable.
三种淋巴母细胞样细胞系（LCLs）的O6-烷基鸟嘌呤-DNA烷基转移酶（O6-AGT）活性极低，被归类为Mex-。它们对1-(4-氨基-2-甲基-5-嘧啶基)-甲基-3-(2-氯乙基)-3-亚硝基脲盐酸盐（ACNU）的细胞杀伤作用高度敏感，而具有高O6-AGT活性的Mex+ LCL NMO2对该药物具有抗性。这些Mex- LCLs中有一小部分在10微克/毫升的ACNU处理24小时后存活下来，并且发现存活细胞对该药物的后续处理具有抗性。此外，它们所含的O6-AGT活性与NMO2相当，因此被视为Mex+。这些结果表明LCLs中的Mex-表型不稳定。
