SV40 DNA replication inhibition by the monofunctional DNA alkylator Et743.
SV40 DNA replication inhibition by the monofunctional DNA alkylator Et743.
复制标题
单功能 DNA 烷基化剂 Et743 对 SV40 DNA 复制的抑制。
DOI：
10.1021/bi049407x
复制
发表时间：
2004
期刊：
影响因子：
2.9
通讯作者：
Beerman,TerryA
中科院分区：
文献类型：
--
作者：
Dziegielewska,Barbara;Kowalski,David;Beerman,TerryA
Et743(Et743)是一种高度细胞毒性的抗癌药物，从鼻甲蠕虫中分离出来，它在富含GC的序列中使小沟中的DNA烷化，导致不寻常的向大沟弯曲。利用哺乳动物细胞和无细胞提取物中哺乳动物DNA复制的猴病毒(SV40)模型，研究了Et743阻止DNA复制的能力。用天然双向琼脂糖凝胶电泳法分析经Et743处理的BSC-1细胞内SV40 DNA。低频率的Et743加合物在药物浓度为30dna，100nM时可抑制−的起始活性，并诱导形成异常的dna复制中间产物。在无细胞条件下，只有较高的Et743加合物频率降低SV40DNA的合成。涉及相关DNA烷化剂托马霉素和沙拉霉素A的比较研究显示，在高于Et743约10倍的浓度时，细胞中的SV40 DNA复制受到抑制。在无细胞条件下，托马霉素或沙拉霉素A加成的DNA模板抑制DNA合成的作用类似于Et743。Et743似乎在其他烷化剂中是不寻常的，因为它的加合物强烈抑制细胞内SV40 DNA复制，但在无细胞条件下作为顺式抑制剂的作用相对较弱。
Ecteinascidin 743 (Et743) is a highly cytotoxic anticancer agent isolated from the squirtEcteinascidia turbinate, which alkylates DNA in the minor groove at GC-rich sequences resulting in an unusual bending toward the major groove. The ability of Et743 to block DNA replication was studied using the well-established simian virus (SV40) model for mammalian DNA replication in cells and cell-free extracts. Intracellular SV40 DNA isolated from Et743-treated BSC-1 cells was analyzed by native, two-dimensional agarose gel electrophoresis. A low frequency of Et743 adducts detected at 30−100 nM drug concentrations inhibited SV40 origin activity and induced formation of unusual DNA replication intermediates. Under cell-free conditions, only a high Et743 adduct frequency reduced SV40 DNA synthesis. Comparative studies involving related DNA alkylators, tomamycin and saframycin A, revealed inhibition of SV40 DNA replication in cells at concentrations approximately 10 times higher than Et743. Under cell-free conditions tomamycin- or saframycin-A-adducted DNA templates inhibited DNA synthesis similarly to Et743. Et743 appears to be unusual among other alkylators, because its adducts strongly inhibit intracellular SV40 DNA replication but are relatively weak as cis inhibitors as measured under cell-free conditions.