Mitani H, Ito K, Fujino M, Takebe H
Mutat Res. 1987 Jul-Aug;191(3-4):201-5. doi: 10.1016/0165-7992(87)90154-0.
We examined the sensitivity to the lethal effects of methylating agents and the O6-methylguanine methyltransferase (MTR) activities of in vitro transformed NIH3T3 cell clones. The sensitivities to the lethal effects of MNNG were not different among all 49 transformed cell clones examined and do not correlate with the MTR activities. All 8 spontaneously transformed cell clones showed the same sensitivities to ACNU as the parental cell line. 2 of 20 transformants induced by UV or MNNG showed higher sensitivities to the ACNU although the MTR activity was normal. One cell clone transformed by UV was sensitive to ACNU and showed about half MTR activity. 5 of 19 cell clones transformed by oncogenes (Ha-ras or SV40 ori-) were sensitive to the lethal effects of ACNU and showed the low MTR activities, but were not as much sensitive as a Ha-MuSV transformed cell clone, Ha821.
我们检测了体外转化的NIH3T3细胞克隆对甲基化剂致死效应的敏感性以及O6-甲基鸟嘌呤甲基转移酶（MTR）的活性。在所检测的全部49个转化细胞克隆中，对MNNG致死效应的敏感性并无差异，且与MTR活性无关。所有8个自发转化细胞克隆对ACNU的敏感性与亲本细胞系相同。紫外线或MNNG诱导的20个转化体中有2个对ACNU表现出更高的敏感性，尽管其MTR活性正常。一个经紫外线转化的细胞克隆对ACNU敏感，且MTR活性约为正常水平的一半。19个由癌基因（Ha-ras或SV40 ori-）转化的细胞克隆中有5个对ACNU的致死效应敏感，且MTR活性较低，但不如Ha-MuSV转化细胞克隆Ha821敏感。
