Background:

WAY 316606 is a selective small-molecule inhibitor of secreted frizzled-related protein-1 (sFRP-1) with EC50 value of 0.65 μM [1].
The Wnt signaling has been proved to be a drug target of treatment for metabolic bone diseases such as osteoporosis. The studies found that loss-of-function mutations of Wnt antagonists caused increased bone formation and deletion of the Wnt antagonist sFRP-1 resulted in increased trabecular bone formation in aged mice. Thus small-molecule inhibitors of Wnt antagonist (sFRP-1) have been discovered and developed. WAY 316606 was screened out from a library of over 440,000 compounds by the cell-based assay measuring activation of Wnt signaling. It bound to sFRP-1 preferentially (Kd value of 0.08 μM) and inhibited the negative regulation of Wnt caused by sFRP-1. WAY 316606 has been proved to promote bone formation in an organ culture assay [1].
WAY 316606 is a selective inhibitor of sFRP-1. It bound to sFRP-2 with 10-fold weaker affinity (Kd value of 1 μM). In a fluorescence polarization binding assay, WAY 316606 inhibited sFRP-1 with IC50 value of 0.5 μM. Although sequence of sFRP-1, -2 and -5 showed high identity, WAY 316606 selectively inhibited sFRP-1 against other two proteins. In the osteosarcoma U2-OS cell line used in a cell-based transient transfection and luciferase reporter assay, treatment of WAY 316606 dose-dependently increased Wnt-signaling with EC50 value of 0.65 μM. In an ex vivo assay using neonatal murine calvarium, treatment of WAY 316606 dose-dependently enhanced the osteoblast activity and stimulated bone formation up to 60% with EC50 value of 1 nM [1 and 2].
Although WAY 316606 had good aqueous solubility and good stability, WAY 316606 exerted high plasma clearance (77 mL/min/kg) in rats, which suppressed sustained exposure and limited the compound's advancement as an orally administered anabolic bone agent [1].
参考文献:
[1] Bodine P V N, Stauffer B, Ponce-de-Leon H, et al. A small molecule inhibitor of the Wnt antagonist secreted frizzled-related protein-1 stimulates bone formation. Bone, 2009, 44(6): 1063-1068.
[2] Moore W J, Kern J C, Bhat R, et al. Modulation of Wnt Signaling Through Inhibition of Secreted Frizzled-Related Protein I (sFRP-1) with N-Substituted Piperidinyl Diphenylsulfonyl Sulfonamides?. Journal of medicinal chemistry, 2008, 52(1): 105-116.