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 (4AGD) and KIT (3G0E) as co-crystals. 3a (3,85 µM and 2,99 µM) and 3c (1,77 µM and 77,31 µM) emerged as two candidates with high cytotoxic potential, exhibiting the lowest IC₅₀ values in MCF-7 and MDA-MB-231 cell lines, respectively, at the 24