Coccia P, Sen S, Erba E, Pagani P, Marinello C, D'Incalci M
Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
Cancer Chemother Pharmacol. 1992;30(1):77-80. doi: 10.1007/BF00686490.
The DNA repair enzyme O6-alkylguanine-DNA alkyltransferase (AT) was analysed in the human ovarian-cancer SW626 cell line and in the human promonocytic leukemia U937 cell line following their synchronisation with low non-toxic concentrations of methotrexate. In SW626, AT increased in the early S phase of the cell cycle and then declined during progression of the S phase to levels found in the G1 phase of unsynchronised cells. In contrast, at the G1/S-phase boundary and in the S phase, U937 cells showed a lower AT content than did exponentially growing unsynchronised cells. In addition, AT activity was greatly reduced in resting U937 cells but was not reduced appreciably in resting SW937 cells but was not reduced appreciably in resting SW626 cells. The results of these studies indicate that AT fluctuations do not follow a constant pattern during the cell cycle of different cell lines.
采用低无毒浓度的甲氨蝶呤对人卵巢癌细胞系SW626和人早幼粒细胞白血病细胞系U937进行同步化处理后，分析了DNA修复酶O6-烷基鸟嘌呤-DNA烷基转移酶（AT）。在SW626细胞中，AT在细胞周期的早期S期增加，然后在S期进展过程中下降至未同步化细胞G1期的水平。相比之下，在G1/S期边界和S期，U937细胞的AT含量低于指数生长的未同步化细胞。此外，静止的U937细胞中AT活性大大降低，但静止的SW626细胞中AT活性没有明显降低。这些研究结果表明，在不同细胞系的细胞周期中，AT的波动并不遵循恒定模式。
