抗微生物药物耐药性对公共卫生产生了重大影响，并继续威胁着抗菌疗法的有效性。新型细菌拓扑异构酶抑制剂（NBTIs）是一类有希望的抗菌剂，具有独特的结合模式和不同的药理学特性，使其能逃避现有的耐药机制。NBTIs的临床开发一直受到多个问题的困扰，包括心血管安全性。在这里，我们报告了一系列具有酰胺连接的三环NBTIs，显示出有前景的抗菌活性，对DNA旋转酶和拓扑异构酶IV（TopoIV）的强效双靶点抑制作用，以及改善了心血管安全性和代谢剖面。这些酰胺NBTIs通过葡萄球菌DNA旋转酶介导引起了pBR322 DNA的单链和双链断裂，而典型的NBTIs只引起单链断裂。令人意外的是，酰胺1a和1b靶向人类拓扑异构酶IIα（TOP2α），导致pBR322 DNA的单链和双链断裂，并使完整的人类白血病K562细胞发生DNA链断裂。此外，包含TOP2α水平降低的抗癌药物耐药K/VP.5细胞对酰胺1a和1b也出现交叉耐药。综上所述，这些结果表明所选三环NBTIs具有广谱抗菌性能、良好的安全性、不寻常的诱导DNA双链断裂能力以及对人类TOP2α的活性。未来的工作将致力于优化和开发针对细菌具有强效和选择性活性的三环NBTIs。最后，当前的结果可能为选择性抗癌剂的开发提供了额外途径。

Antimicrobial resistance has made a sizeable impact on public health and continues to threaten the effectiveness of antibacterial therapies. Novel bacterial topoisomerase inhibitors (NBTIs) are a promising class of antibacterial agents with a unique binding mode and distinct pharmacology that enables them to evade existing resistance mechanisms. The clinical development of NBTIs has been plagued by several issues, including cardiovascular safety. Herein, we report a sub-series of tricyclic NBTIs bearing an amide linkage that displays promising antibacterial activity, potent dual-target inhibition of DNA gyrase and topoisomerase IV (TopoIV), as well as improved cardiovascular safety and metabolic profiles. These amide NBTIs induced both single- and double-strand breaks in pBR322 DNA mediated by Staphylococcus aureus DNA gyrase, in contrast to prototypical NBTIs that cause only single-strand breaks. Unexpectedly, amides 1a and 1b targeted human topoisomerase IIα (TOP2α) causing both single- and double-strand breaks in pBR322 DNA, and induced DNA strand breaks in intact human leukemia K562 cells. In addition, anticancer drug-resistant K/VP.5 cells containing decreased levels of TOP2α were cross-resistant to amides 1a and 1b. Together, these results demonstrate broad spectrum antibacterial properties of selected tricyclic NBTIs, desirable safety profiles, an unusual ability to induce DNA double-stranded breaks, and activity against human TOP2α. Future work will be directed toward optimization and development of tricyclic NBTIs with potent and selective activity against bacteria. Finally, the current results may provide an additional avenue for development of selective anticancer agents.