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. 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.

Development of Benzimidazole-Substituted Spirocyclopropyl Oxindole Derivatives as Cytotoxic Agents: Tubulin Polymerization Inhibition and Apoptosis Inducing Studies.

A series of spirocyclopropyl oxindoles with benzimidazole substitutions was synthesized and tested for their cytotoxicity against selected human cancer cells. Most of the molecules exhibited significant antiproliferative activity with compound 12 p being the most potent. It exhibited significant cytotoxicity against MCF-7 breast cancer cells (IC50 value 3.14±0.50 µM), evidenced by the decrease in viable cells and increased apoptotic features during phase contrast microscopy, such as AO/EB, DAPI and DCFDA staining studies. Compound 12 p also inhibited cell migration in wound healing assay. Anticancer potential of 12 p was proved by the inhibition of tubulin polymerization with IC50 of 5.64±0.15 µM. These results imply the potential of benzimidazole substituted spirocyclopropyl oxindoles, notably 12 p, as cytotoxic agent for the treatment of breast cancer.