Design, Development of Pyrazole‐Linked Spirocyclopropyl Oxindole‐Carboxamides as Potential Cytotoxic Agents and Type III Allosteric VEGFR‐2 Inhibitors

Tumor progression depends on angiogenesis, which is stimulated by growth factors like VEGF, targeting VEGFR kinase with small molecules is an effective anti‐angiogenic therapeutic approach. The rational modification of sunitinib (VEGFR‐2 inhibitor) to spirocyclopropyloxindoline carboxamides have been performed and their in vitro cytotoxic profiling was evaluated. The molecular modelling studies enabled the screening of designed analogues and identifying the possible interactions within the type III allosteric inhibitor binding site of VEGFR‐2. The biological screening of synthesized compounds 15 a–y, revealed the ability of compound 15 w to inhibit the cell growth in MCF‐7 cell line with IC50 value of 3.87±0.19 μM and alongside inhibition of VEGFR‐2 kinase at a IC50 concentration of 4.34±0.13 μM was observed. Also, VEGFR‐2 inhibition was validated through HUVEC tube formation inhibition assay. The qualitative assessment of apoptosis induction by 15 w in MCF‐7 cells was evaluated through staining studies such as AO/EB and DAPI staining, whereas quantification of apoptosis and cell cycle analysis were performed through FACS analysis. The metastatic ability of the cancer cells was evaluated through inhibition of cell migration by a scratch wound healing assay. The current study strives to sequentially optimize the structural attributes of the 3‐alkenyl oxindole core to surpass the existing challenges of well‐known VEGFR‐2 inhibitors. The findings observed from this study highlights that compound 15 w to be a prominent lead towards the development of clinical drug candidates. A novel series of spirocyclopropyloxindoline carboxamides were synthesized, which were screened for VEGFR‐2 kinase inhibition. Compound 15 w emerged as a potent inhibitor with an IC50 of 4.34 μM against VEGFR‐2 and 3.87 μM in MCF‐7 cell cytotoxicity. It also inhibited HUVEC tube formation and cell migration, induced apoptosis, and showed promise as a lead for anti‐angiogenic drug development.