Design, synthesis, anticancer activity, bioimaging, and molecular docking of novel fluorescent isatin derivatives

Breast cancer remains a leading global health challenge, driving the urgent need for innovative therapeutic strategies. This study presents the initial results of the design, synthesis, characterization, and in vitro evaluation of a novel fluorescent agent for breast cancer treatment, focusing on its subcellular localization and molecular docking. Seven novel fluorescent compounds ( 3a-g ) were synthesized via isatin derivatives and 4-bromo 1,8-naphthalimide conjugation. The compounds were spectroscopically characterized and tested in MDA-MB-231 and MCF-7 cells using viability assays, Annexin-V and propidium iodide flow cytometry to define cytotoxic mechanisms, confocal microscopy with nuclear and mitochondrial markers for subcellular localization, and molecular docking to VEGFR2. Several conjugates, particularly 3a and 3g in MCF-7 and 3c in MDA-MB-231, showed strong activity, while 3b was observed to be largely inactive. Docking indicated that 3c binds VEGFR2 through a binding mode distinct from sunitinib, supporting its promise as a lead together with 3a .