Design, synthesis, and molecular docking of novel indole scaffold-based VEGFR-2 inhibitors as targeted anticancer agents.

A series of new indole derivatives 1-18 was synthesized and tested for their cytotoxic activity on a panel of 60 tumor cell lines. Additionally, molecular docking was carried out to study their binding pattern and binding affinity in the VEGFR-2 active site using sorafenib as a reference VEGFR-2 inhibitor. Based on the molecular docking results, compounds 5a, 5b, 6, 7, 14b, 18b, and 18c were selected to be evaluated for their VEGFR-2 inhibitory activity. Compound 18b exhibited a broad-spectrum antiproliferative activity on 47 cell lines, with GI % ranging from 31 to 82.5%. Moreover, compound 18b was the most potent VEGFR-2 inhibitor with an IC50 value of 0.07 μM, which is more potent than that of sorafenib (0.09 μM). A molecular docking study attributed the promising activity of this series to their hydrophobic interaction with the VEGFR-2 binding site hydrophobic side chains and their hydrogen bonding interaction with the key amino acids Glu885 and/or Asp1046.