With a goal of identifying potent topoisomerase (topo) inhibitor, the C4-aromatic ring of the anticancer agent, 3,4-diarylisoquinolone, was strategically shifted to design 1,3-diarylisoquinoline. Twenty-two target compounds were synthesized in three simple and efficient steps. The 1,3-diarylisoquinolines exhibited potent anti-proliferative effects on cancer cells but few compounds spared non-cancerous cells. Inhibition of topo I/IIα-mediated DNA relaxation by several derivatives was greater than that by camptothecin (CPT)/etoposide even at low concentration (20 μM). In addition, these compounds had little or no effect on polymerization of tubulin. A series of biological evaluations performed with the most potent derivative 4cc revealed that the compound is a non-intercalative topo I catalytic inhibitor interacting with free topo I. Collectively, the potent cytotoxic effect on cancer cells including the drug resistance ones, absence of lethal effect on normal cells, and different mechanism of action than topo I poisons suggest that the 1,3-diarylisoquinolines might be a promising class of anticancer agents worthy of further pursuit.

为了鉴定有效的拓扑异构酶（拓扑）抑制剂，将抗癌药3,4-二芳基异喹诺酮的C4-芳族环策略性地转移到设计1,3-二芳基异喹啉上。通过三个简单有效的步骤合成了22种目标化合物。1,3-二芳基异喹啉类药物对癌细胞具有有效的抗增殖作用，但很少有化合物能幸免于非癌细胞。即使在低浓度（20μM）下，几种衍生物对topo I /IIα介导的DNA松弛的抑制作用也比喜树碱（CPT）/依托泊苷高。另外，这些化合物对微管蛋白的聚合几乎没有影响。用最有效的衍生物4cc进行的一系列生物学评估 揭示了该化合物是一种与游离topo I相互作用的非插入式topo I催化抑制剂。总的来说，它对癌细胞具有强力的细胞毒性作用，包括耐药性，对正常细胞没有致死作用以及与topo I不同的作用机制。毒物表明1,3-二芳基异喹啉可能是一类有前途的抗癌药物，值得进一步研究。