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.
Protocol
Kinase experiment: | WAY-316606 binding to purified sFRP is determined by spectroscopy methods. The sFRP-1 or -2 stock solutions are diluted to 1 μM in a buffered solution and the initial fluorescence is measured. Increasing concentrations of WAY-316606 (0 to 50 μM) are added to the protein in the cuvette and incubated for 5 min prior to assessing fluorescence intensity using a Fluoromax-2 fluorometer. In control experiments, the DMSO (vehicle control)-matched buffer solution is used. Fluorescence spectra are scanned in the ratio mode (S/R, signal/reference) to compensate for variations in lamp output as a function of wavelength. Fluorescence changes are fitted to a quadratic equation to obtain apparent dissociation constants[2]. |
Cell experiment: | U2OS bone cells are infected with recombinant adenovirus 5 (Ad5)?WNT3 at a multiplicity of infection (MOI) of 2, followed by infection with Ad5-sFRP-1 and Ad5-16xTCF-luciferase, each at an MOI of 10. Four hours after infection, the cells are frozen in sterile cryogenic vials at a cell density of 9×106 cells/mL and stored in a ?150°C freezer. For the assay, a vial of frozen cells is thawed, and the cells are resuspended in plating medium [phenol red-free RPMI 1640 medium containing 5% fetal calf serum, 2 mM GlutaMAX-l, and 1% (v/v) penicillin-streptomycin] to a final cell density of 1.5×105 cells/mL. The resuspended cells are then plated in 96-well tissue culture treated plates at a volume of 100 μL of cell suspension/well (i.e., 1.5×104 cells/well). The plates are incubated at 37°C inside a 5% CO2/ 95% humidified air incubator for 5 h or until the cells have attached and started to spread. Prior to the addition of WAY-316606, the medium is replaced with 50 μL/well of phenol red-free RPMI 1640 containing 10% fetal calf serum, 2 mM GlutaMAX-l, and 1% (v/v) penicillin-streptomycin. WAY-316606, or vehicle (typically DMSO), diluted in phenol red-free RPMI 1640 containing 2 mM GlutaMAX-l, and l % (v/v) penicillin-streptomycin are then added to the wells in replicates of 4 wells/dilution and the plates are incubated at 37°C overnight. Dose?response experiments are performed with the compounds in 2-fold serial dilutions from 10000?4.9 nM. After the overnight incubation, the cells are washed twice with 150 uL/well of PBS w/o calcium or magnesium and lysed with 50 μL/well of 1× cell culture lysis reagent on a shaker at room temperature for 30 min. Aliquots of the cell lysates (30 μL) are transferred to 96-well luminometer plates, and the luciferase activity is measured in a MicroLumat PLUS luminometer using 100 μL/well of luciferase substrate. |
参考文献: [1]. Moore, WJ, 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 (2009), 52(1), 105-116.
[2]. Bodine PV, et al. A small molecule inhibitor of the Wnt antagonist secreted frizzled-related protein-1 stimulates bone formation. Bone. 2009 Jun;44(6):1063-8. |
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