Covalent binding of antitumor benzoacronycines to double-stranded DNA induces helix opening and the formation of single-stranded DNA: unique consequences of a novel DNA-bonding mechanism.
Covalent binding of antitumor benzoacronycines to double-stranded DNA induces helix opening and the formation of single-stranded DNA: unique consequences of a novel DNA-bonding mechanism.
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DOI：
10.1158/1535-7163.71.4.1
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发表时间：
2005-01
影响因子：
5.7
通讯作者：
M. David-Cordonnier;W. Laine;A. Lansiaux;F. Rosu;P. Colson;E. De Pauw;S. Michel;F. Tillequin;M. Koch;J. Hickman;A. Pierré;C. Bailly
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文献类型：
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作者：
M. David-Cordonnier;W. Laine;A. Lansiaux;F. Rosu;P. Colson;E. De Pauw;S. Michel;F. Tillequin;M. Koch;J. Hickman;A. Pierré;C. Bailly
目前已知的大多数DNA结合小分子都能稳定双链DNA，防止热变性。药物引起的DNA熔化温度（Tm）的高升高通常被认为是选择DNA配体的良好标准，也是一些抗癌药物的共同特征，如插入剂（如蒽环类药物）和烷基化剂（如ecteinascidin 743）。相反的情况（DNA的不稳定以促进其变性）可能是鉴定作用于DNA结构的治疗剂的一个有吸引力的选择。我们已经鉴定出具有肿瘤活性的苯并缩氨酸衍生物S23906-1[(+/-)-顺-1,2-二乙酰氧基-6-甲氧基-3,3,14-三甲基-1,2,3,14-四氢- 7h -苯并[b]吡喃[3,2]吖啶-7- 1]是一种具有解旋酶样活性的有效DNA烷基化剂。利用互补分子方法，我们发现双乙酸化合物S23906-1及其单乙酸类似物S28687-1与DNA的共价结合诱导了双螺旋结构的明显不稳定，形成烷基化的ssDNA。采用互补的生化（电迁移位移测定、核酸酶S1定位）和光谱学（荧光和Tm测量）方法，研究了一系列苯并缩氨酸衍生物（包括二氨基甲酸酯类似物S29385-1）的DNA键合特性及其对DNA结构的影响。DNA中的鸟嘌呤被S28687-1烷基化，导致DNA局部变性，易被核酸酶S1切割，显著降低DNA的Tm。该药物也直接烷基化单链DNA，但质谱实验表明，双链结构的鸟嘌呤在很大程度上优于单链结构。这项分子研究扩大了DNA结合机制的范围，并为小分子DNA识别提供了一个新的维度。
The majority of DNA-binding small molecules known thus far stabilize duplex DNA against heat denaturation. A high, drug-induced increase in the melting temperature (Tm) of DNA is generally viewed as a good criterion to select DNA ligands and is a common feature of several anticancer drugs such as intercalators (e.g., anthracyclines) and alkylators (e.g., ecteinascidin 743). The reverse situation (destabilization of DNA to facilitate its denaturation) may be an attractive option for the identification of therapeutic agents acting on the DNA structure. We have identified the tumor-active benzoacronycine derivative S23906-1 [(+/-)-cis-1,2-diacetoxy-6-methoxy-3,3,14-trimethyl-1,2,3,14-tetrahydro-7H-benzo[b]pyrano[3,2]acridin-7-one] as a potent DNA alkylating agent endowed with a helicase-like activity. Using complementary molecular approaches, we show that covalent binding to DNA of the diacetate compound S23906-1 and its monoacetate analogue S28687-1 induces a marked destabilization of the double helix with the formation of alkylated ssDNA. The DNA-bonding properties and effects on DNA structure of a series of benzoacronycine derivatives, including the dicarbamate analogue S29385-1, were studied using complementary biochemical (electromobility shift assay, nuclease S1 mapping) and spectroscopic (fluorescence and Tm measurements) approaches. Alkylation of guanines in DNA by S28687-1 leads to a local denaturation of DNA, which becomes susceptible to cleavage by nuclease S1 and significantly decreases the Tm of DNA. The drug also directly alkylates single-strand DNA, but mass spectrometry experiments indicate that guanines in duplexes are largely preferred over single-stranded structures. This molecular study expands the repertoire of DNA-binding mechanisms and provides a new dimension for DNA recognition by small molecules.