Reduction of BCNU toxicity to lung cells by high-level expression of O(6)-methylguanine-DNA methyltransferase.
Reduction of BCNU toxicity to lung cells by high-level expression of O(6)-methylguanine-DNA methyltransferase.
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DOI：
10.1152/ajplung.2001.280.4.l755
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发表时间：
2001-04
期刊：
影响因子：
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通讯作者：
M. Wu;M. Kelley;W. K. Hansen;W. Martin
中科院分区：
文献类型：
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作者：
M. Wu;M. Kelley;W. K. Hansen;W. Martin
1,3-双（2-氯乙基）-1-亚硝基脲（BCNU）是肺毒性的重要原因。BCNU在鸟嘌呤的O(6)位置烷基化DNA。O(6)-甲基鸟嘌呤-DNA甲基转移酶（MGMT）是一种DNA修复蛋白，可以去除鸟嘌呤O(6)位置上的烷基。为了确定MGMT在肺细胞中的过表达是否会降低BCNU毒性，我们将MGMT基因转染到肺上皮细胞系A549细胞中。转染的A549细胞群显示出高水平的MGMT RNA、MGMT蛋白和DNA修复活性。MGMT在肺上皮细胞中的过表达对BCNU的细胞毒性作用具有保护作用。对照A549细胞与100 microM BCNU孵育后，细胞存活率为12.5 +/- 1.2%；而过表达MGMT的A549细胞存活率为71.8±2.7% （P < 0.001）。我们还成功地将MGMT转染到人肺动脉内皮细胞中，并成功培养了MGMT过表达的大鼠II型肺泡上皮细胞，从而对BCNU毒性产生了显著的保护作用。这些数据表明，肺细胞中DNA修复蛋白（如MGMT）的过度表达可能保护肺细胞免受BCNU等癌症化疗药物的细胞毒性作用。
1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) is an important cause of pulmonary toxicity. BCNU alkylates DNA at the O(6) position of guanine. O(6)-methylguanine-DNA methyltransferase (MGMT) is a DNA repair protein that removes alkyl groups from the O(6) position of guanine. To determine whether overexpression of MGMT in a lung cell reduces BCNU toxicity, the MGMT gene was transfected into A549 cells, a lung epithelial cell line. Transfected A549 cell populations demonstrated high levels of MGMT RNA, MGMT protein, and DNA repair activity. The overexpression of MGMT in lung epithelial cells provided protection from the cytotoxic effects of BCNU. Control A549 cells incubated with 100 microM BCNU had a cell survival rate of 12.5 +/- 1.2%; however, A549 cells overexpressing MGMT had a survival rate of 71.8 +/- 2.7% (P < 0.001). We also demonstrated successful transfection of MGMT into human pulmonary artery endothelial cells and a primary culture of rat type II alveolar epithelial cells with overexpression of MGMT, resulting in significant protection from BCNU toxicity. These data suggest that overexpression of DNA repair proteins such as MGMT in lung cells may protect the lung cells from cytotoxic effects of cancer chemotherapy drugs such as BCNU.