Takaaki Inaba

Conformation-activity relationship on novel 4-pyridylmethylthio derivatives with antiangiogenic activity.

We found 4-pyridylmethylthio derivative 1 to be very effective in using antiangiogenesis activity to prevent proliferation of HUVECs (Human Umbilical Vein Endothelial Cells), which was induced by vascular endothelial growth factor (VEGF). Compound 1 was equally effective in inhibiting VEGF receptor2 tyrosine kinase (KDR, IC(50)=26nM). We deduced that the inhibition was the result of binding the catalytic domain of VEGF receptor2 tyrosine kinase in a similar fashion to both phthalazine derivative PTK787 2 and anthranylamide derivative AAL993 3. In this report, we will describe the conformational analyses, from ab initio MO calculation and X-ray crystallographic analyses, of compound 1 and the analogs, which include non-active 9, all in comparison with 2 and 3. The conformation-activity relationships suggest that a nonbonded intramolecular interaction between the sulfur and the carbonyl oxygen of 1 was very important in inhibiting KDR.

Pyridylmethylthio derivatives as VEGF inhibitors: Part 2

Optimization of compounds 5 and 6 led to the discovery of VEGF inhibitor 10g which reduced CYP inhibition. It was highly active in vitro (VEGF induced HUVEC proliferation assay) and showed efficacies in three disease models in vivo (cancer, RA, and AMD).