Twisted amides based on the spirohydantoin scaffold as potential anticancer agents

• DOI: 10.1016/j.molstruc.2025.141680
• Publication Date: 2025-02-06T16:54:38Z
• Authors: Anita Lazić; Relja Suručić; Nađa Grozdanić St...; Jelena Popović-Dj...; Nebojša Banjac; Tatjana Stanojković; Nemanja Trišović
• Keywords: VEGFR-2; Cytotoxic activity; Twisted amide; Drug-likeness; Spirohydantoin

A series of cyclohexanespiro5-hydantoins bearing either a 4-substituted benzoyl group (compounds 1–6) or a 2-(4-substituted phenyl)-2-oxoethyl group (compounds 7, 8) in position 3 was synthesized and structurally characterized. Compounds 1–6 feature a distorted exocyclic amide bond that results from the twisting in a combination with pyramidalization of the N3 atom. Particularly, compound with a fluoro substituent (3) contains one of the most distorted acyclic amide bonds reported so far. The cytotoxic effects of the investigated compounds were evaluated against human cancer cell lines: cervical adenocarcinoma (HeLa), colorectal adenocarcinoma (LS174T), lung epithelial carcinoma (A549) as well as normal human lung fibroblasts (MRC5) cell line. It appeared that moderately distorted twisted amides with highly lipophilic substituents showed high cytotoxic potency against selected cancer cell lines. Compound 6 bearing a tert‑butyl group demonstrated the highest cytotoxic activity against all cell lines tested, with IC50 values ranging from 10.08±3.90 to 15.86±4.64 µM against HeLa and LS174T cell line, respectively. Compound 5 with a bromo substituent was the next one in terms of cytotoxic activity against HeLa cell line with IC50 value of 36.03±10.15 µM and against LS174T cell line with IC50 value of 48.03±3.92 µM. This compound showed the highest selectivity toward HeLa cell line compared to normal MRC cell line with the selectivity coefficient of 2.42. The cell cycle analysis demonstrated that compounds 5 and 6 exerted a potent proapoptotic effect on HeLa cancer cells in vitro. Furthermore, we analyzed the molecular binding features of the investigated compounds with the vascular endothelial growth factor receptor 2 (VEGFR-2) that is responsible for stimulation of pathological angiogenesis. The study of structural and biological properties of the investigated compounds provided guidelines for the development of twisted amides with potential cytotoxic activity.