2-(4-Bromobenzyl) tethered 4-amino aryl/alkyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidines: design, synthesis, anticancer assessment via dual topoisomerase-I/II inhibition, and in silico studies†

Abstract

A series of 2-(4-bromobenzyl) tethered 4-amino aryl/alkyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidines (7a–7u) were designed, synthesized, characterized and screened against a panel of cancer cell lines. Compound 7a, in particular, emerged as a potent antiproliferative agent against FaDu cells (HTB-43) with an IC₅₀ value of 1.73 μM. 7a induced morphological alterations in FaDu cells were observed via brightfield microscopy and DAPI staining, confirming cytotoxicity. Autophagy and apoptotic effects of 7a were confirmed by acridine orange staining, Rhodamine 123 staining, and western blot analysis, which revealed dose-dependent increases in LC3A/B and cleaved caspase-3 levels, respectively. Further, 7a impaired cell migration and colony formation, as demonstrated by scratch and clonogenic assays. Additionally, 7a reduced oxidative stress and induced G2/M phase cell cycle arrest in MCF-7 cells. 7a emerged as a dual topoisomerase I and II inhibitor, and results were supported by molecular docking and simulation studies. In anti-inflammatory studies, 7a exhibited selective inhibition of COX-2 over COX-1, supporting its dual anticancer and anti-inflammatory properties.