Atwell G J, Fan J Y, Tan K, Denny W A
Auckland Cancer Society Research Centre, Faculty of Medicine and Health Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
J Med Chem. 1998 Nov 19;41(24):4744-54. doi: 10.1021/jm9803119.
A series of bis(hydroxymethyl)-substituted imidazoles, thioimidazoles, and pyrrolizines and related bis(carbamates), linked to either 9-anilinoacridine (intercalating) or 4-(4-quinolinylamino)benzamide (minor groove binding) carriers, were synthesized and evaluated for sequence-specific DNA alkylation and cytotoxicity. The imidazole and thioimidazole analogues were prepared by initial synthesis of [(4-aminophenyl)alkyl]imidazole-, thioimidazole-, or pyrrolizine dicarboxylates, coupling of these with the desired carrier, and reduction to give the required bis(hydroxymethyl) alkylating moiety. The pyrrolizines were the most reactive alkylators, followed by the thioimidazoles, while the imidazoles were unreactive. The pyrrolizines and some of the thioimidazoles cross-linked DNA, as measured by agarose gel electrophoresis. Strand cleavage assays showed that none of the compounds reacted at purine N7 or N3 sites in the gpt region of the plasmid gpt2Eco, but the polymerase stop assay showed patterns of G-alkylation in C-rich regions. The corresponding thioimidazole bis(carbamates) were more selective than the bis(hydroxymethyl) pyrrolizines, with high-intensity bands at 5'-NCCN, 5'-NGCN and 5'-NCGN sequences in the PCR stopping assay ( indicates block sites). The data suggest that these targeted compounds, like the known thioimidazole bis(carbamate) carmethizole, alkylate exclusively at guanine residues via the 2-amino group, with little or no alkylation at N3 and N7 guanine or adenine sites. The cytotoxicities of the compounds correlated broadly with their reactivities, with the bis(hydroxymethyl)imidazoles being the least cytotoxic (IC50s >1 microM; P388 leukemia) and with the intercalator-linked analogues being more cytotoxic than the corresponding minor-groove-targeted ones. This was true also for the more reactive thioimidazole bis(carbamates) (IC50s 0.8 and 11 microM, respectively), but both were more active than the analogous "untargeted" carmethizole (IC50 20 microM). The bis(hydroxymethyl)pyrrolizine analogues were the most cytotoxic, with IC50s as low as 0.03 microM.
合成了一系列与9-苯胺基吖啶（嵌入剂）或4-（4-喹啉基氨基）苯甲酰胺（小沟结合剂）载体相连的双（羟甲基）取代的咪唑、硫代咪唑和吡咯嗪以及相关的双（氨基甲酸酯），并对其序列特异性DNA烷基化和细胞毒性进行了评估。咪唑和硫代咪唑类似物通过最初合成[(4-氨基苯基)烷基]咪唑、硫代咪唑或吡咯嗪二羧酸酯，将这些与所需载体偶联，然后还原得到所需的双（羟甲基）烷基化部分来制备。吡咯嗪是反应性最强的烷基化剂，其次是硫代咪唑，而咪唑则无反应性。通过琼脂糖凝胶电泳测定，吡咯嗪和一些硫代咪唑会使DNA交联。链断裂分析表明，这些化合物在质粒gpt2Eco的gpt区域的嘌呤N7或N3位点均无反应，但聚合酶终止分析显示在富含C的区域有G-烷基化模式。相应的硫代咪唑双（氨基甲酸酯）比双（羟甲基）吡咯嗪更具选择性，在PCR终止分析中，在5'-NCCN、5'-NGCN和5'-NCGN序列处有高强度条带（表示阻断位点）。数据表明，这些靶向化合物与已知的硫代咪唑双（氨基甲酸酯）卡美噻唑一样，仅通过2-氨基在鸟嘌呤残基处烷基化，在鸟嘌呤或腺嘌呤的N3和N7位点几乎没有或没有烷基化。这些化合物的细胞毒性与其反应性大致相关，双（羟甲基）咪唑的细胞毒性最小（IC50s>1 microM；P388白血病），与嵌入剂相连的类似物比相应的小沟靶向类似物细胞毒性更大。反应性更强的硫代咪唑双（氨基甲酸酯）也是如此（IC50s分别为0.8和11 microM），但两者均比类似的“非靶向”卡美噻唑（IC50 20 microM）更具活性。双（羟甲基）吡咯嗪类似物的细胞毒性最大，IC50低至0.03 microM。
