DNA replication and repair are complex processes accomplished by the concerted action of a network of enzymes and proteins. DNA ligases play a crucial role in these processes by catalyzing the nick joining between DNA strands. As compared to normal cells, elevated levels of human DNA ligase I (hLigI) is reported in some cancers. We studied the inhibition of hLigI mediated DNA nick sealing activity followed by the antiproliferative activity of novel indole-chalcone based benzopyran compounds on cancer cells. One molecule called compound 27 showed a notable preference for inhibition of hLigI as compared to other ligases and showed enhanced cytotoxicity against colon cancer (DLD-1) cells as compared to normal cells. Mechanistic studies showed that compound 27 directly interacts with hLigI in a competitive manner and did not interact with the DNA substrate during ligation. This novel and potent hLigI inhibitor showed significant inhibition of both monolayer culture as well as 3D culture of DLD-1 cells that mimic solid tumor. It also affected the migration of DLD-1 cells indicating the potential anti-metastatic activity. This novel hLigI inhibitor could therefore serve as a promising lead for anticancer drug development.

DNA复制和修复是复杂的过程，通过酶和蛋白质网络的协同作用来完成。DNA连接酶通过催化DNA链之间的缺口连接，在这些过程中起着至关重要的作用。与正常细胞相比，据报道在某些癌症中人类DNA连接酶I（hLigI）的水平升高。我们研究了抑制hLigI介导的DNA切口封闭活性，然后研究了基于吲哚-查尔酮的新型苯并吡喃化合物对癌细胞的抗增殖活性。与其他连接酶相比，一种称为化合物27的分子表现出对hLigI抑制的显着偏好，与正常细胞相比，对结肠癌（DLD-1）细胞的细胞毒性增强。机理研究表明，化合物27在连接过程中直接与hLigI相互作用，而与DNA底物不相互作用。这种新型有效的hLigI抑制剂对模拟实体瘤的DLD-1细胞的单层培养和3D培养均显示出显着抑制作用。它还影响了DLD-1细胞的迁移，表明其潜在的抗转移活性。因此，这种新颖的hLigI抑制剂可以作为抗癌药物开发的有希望的先导。