Design and synthesis of new substituted spirooxindoles as potential inhibitors of the MDM2–p53 interaction

The designed compounds, 4a–p, were synthesized using a simple and smooth method with an asymmetric 1,3-dipolar reaction as the key step. The chemical structures for all synthesized compounds were elucidated and confirmed by spectral analysis. The molecular complexity and the absolute stereochemistry of 4b and 4e designed analogs were determined by X-ray crystallographic analysis. The anticancer activities of the synthesized compounds were tested against colon (HCT-116), prostate (PC-3), and hepatocellular (HepG-2) cancer cell lines. Molecular modeling revealed that the compound 4d binds through hydrophobic–hydrophobic interactions with the essential amino acids (LEU: 57, GLY: 58, ILE: 61, and HIS: 96) in the p53-binding cleft, as a standard p53-MDM2 inhibitor (6SJ). The mechanism underlying the anticancer activity of compound 4d was further evaluated, and the study showed that compound 4d inhibited colony formation, cell migration, arrested cancer cell growth at G2/M, and induced apoptosis through intrinsic and extrinsic pathways. Transactivation of p53 was confirmed by flow cytometry, where compound 4d increased the level of activated p53 and induced mRNA levels of cell cycle inhibitor, p21.