Design, development of pyrazole-linked spirocyclopropyl oxindole-carboxamides as potential cytotoxic agents and Type III allosteric VEGFR-2 inhibitors.

ABSTRACT

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. Sunitinib was rationally modified to spirocyclopropyloxindoline carboxamides and their in vitro cytotoxic profiling were evaluated. The molecular modelling studies enabled the screening of designed analogues and identified possible interactions within the type III allosteric inhibitor binding site of VEGFR-2. The biological screening of compounds 15a-y, revealed the ability of compound 15w to inhibit the cell growth in MCF-7 cells 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. VEGFR-2 inhibition was validated through HUVEC tube formation inhibition assay. 15w also inhibited cell migration in wound healing assay. The qualitative assessment of apoptosis induction by 15w in MCF-7 cells was evaluated through AO/EB and DAPI staining studies, whereas apoptotic quantification and cell cycle analysis were performed through FACS analysis. The current study strives to sequentially optimize the structural attributes of 3-alkenyl oxindole core to surpass the existing challenges of well-known VEGFR-2 inhibitors and compound 15w was identified to be a prominent lead towards the development of clinical drug candidates.