Improvement of physiochemical properties of the tetrahydroazepinoindole series of farnesoid X receptor (FXR) agonists: beneficial modulation of lipids in primates.

In an effort to develop orally active farnesoid X receptor (FXR) agonists, a series of tetrahydroazepinoindoles with appended solubilizing amine functionalities were synthesized. The crystal structure of the previously disclosed FXR agonist, 1 (FXR-450), aided in the design of compounds with tethered solubilizing functionalities designed to reach the solvent cavity around the hFXR receptor. These compounds were soluble in 0.5% methylcellulose/2% Tween-80 in water (MC/T) for oral administration. In vitro and in vivo optimization led to the identification of 14dd and 14cc, which in a dose-dependent fashion regulated low density lipoprotein cholesterol (LDLc) in low density lipoprotein receptor knockout (LDLR(-/-)) mice. Compound 14cc was dosed in female rhesus monkeys for 4 weeks at 60 mg/kg daily in MC/T vehicle. After 7 days, triglyceride (TG) levels and very low density lipoprotein cholesterol (VLDLc) levels were significantly decreased and LDLc was decreased 63%. These data are the first to demonstrate the dramatic lowering of serum LDLc levels by a FXR agonist in primates and supports the potential utility of 14cc in treating dyslipidemia in humans beyond just TG lowering.

A small molecule inhibitor of the Wnt antagonist secreted frizzled-related protein-1 stimulates bone formation.

Canonical Wnt signaling has been demonstrated to increase bone formation, and Wnt pathway components are being pursued as potential drug targets for osteoporosis and other metabolic bone diseases. Deletion of the Wnt antagonist secreted frizzled-related protein (sFRP)-1 in mice activates canonical signaling in bone and increases trabecular bone formation in aged animals. We have developed small molecules that bind to and inhibit sFRP-1 in vitro and demonstrate robust anabolic activity in an ex vivo organ culture assay. A library of over 440,000 drug-like compounds was screened for inhibitors of human sFRP-1 using a cell-based functional assay that measured activation of canonical Wnt signaling with an optimized T-cell factor (TCF)-luciferase reporter gene assay. One of the hits in this screen, a diarylsulfone sulfonamide, bound to sFRP-1 with a K(D) of 0.35 microM in a tryptophan fluorescence quenching assay. This compound also selectively inhibited sFRP-1 with an EC(50) of 3.9 microM in the cell-based functional assay. Optimization of this high throughput screening hit for binding and functional potency as well as metabolic stability and other pharmaceutical properties led to improved lead compounds. One of these leads (WAY-316606) bound to sFRP-1 with a K(D) of 0.08 microM and inhibited it with an EC(50) of 0.65 microM. Moreover, this compound increased total bone area in a murine calvarial organ culture assay at concentrations as low as 0.0001 microM. This work demonstrates the feasibility of developing small molecules that inhibit sFRP-1 and stimulate canonical Wnt signaling to increase bone formation.

Modulation of Wnt signaling through inhibition of secreted frizzled-related protein I (sFRP-1) with N-substituted piperidinyl diphenylsulfonyl sulfonamides.

The diphenylsulfonyl sulfonamide scaffold represented by 1 (WAY-316606) are small molecule inhibitors of the secreted protein sFRP-1, an endogenous antagonist of the secreted glycoprotein Wnt. Modulators of the Wnt pathway have been proposed as anabolic agents for the treatment of osteoporosis or other bone-related disorders. Details of the structure-activity relationships and biological activity from the first structural class of this scaffold will be discussed.