Selective VEGFR-2 inhibitors: Synthesis of pyridine derivatives, cytotoxicity and apoptosis induction profiling

VEGFR-2 is a key regulator in Cancer angiogenesis. This research displays the design and synthesis of novel 3-cyano-6-naphthylpyridine scaffold-based derivatives as selective VEGFR-2 inhibitors and cytotoxic agents. In vitro percent kinase activity inhibition screening against a panel of 23 kinases at a single high dose (30 nM) affirmed that VEGFR-2 was selectively the most responsive to inhibition by the investigated chemotypes. IC₅₀ values determination demonstrated kinase inhibitory activities of the test compounds at the sub-nanomolar level. In vitro testing of the new compounds against two prostate Cancer cell lines namely PC3 and DU145 and two breast Cancer cell lines namely MCF-7 and MDA-MB435 confirmed their potent cytotoxic activity with IC₅₀s at the nanomolar level. The most active compound against MCF-7 viz.11d was subjected to an in vivo examination against a xenograft mouse model and was found effective. Studying the tissue mRNA expression levels of various cell cycle controlling biomolecules in 11d-treated MCF-7 cells demonstrated (i) upregulation of p53, p21 and p27, (ii) cleavage of PARP protein, (iii) activation of Caspase-3, -8 and -9, (iv) downregulation of the anti-apoptotic protein Bcl, (v) upregulation of the pro-apoptotic protein Bax, and (vi) decreased expression of Cdks 2, 4, 6 and cyclin D1. Additionally, 11d affected a cell cycle arrest at the G1 phase in treated MCF-7 cells and an S phase arrest in MCF-7 p53 knockdown cells. Additionally, molecular docking was performed to predict how 11d might bind to its biological target VEGFR-2. Finally, in-silico ADME and drug-likeness profiling of these derivatives demonstrated favorable properties thereof.