P005091 (P5091) is a selective and potent inhibitor of ubiquitin-specific protease 7 (USP7) with EC50 of 4.2 μM.

USP7:4.2 μM

Recombinant enzymes in 20 mM Tris-HCl (pH 8.0), 2 mM CaCl2, and 2 mM β-mercaptoethanol are incubated with dose ranges of P005091 for 30 min in a 96-well plate before the addition of Ub-PLA2 and NBD C6-HPC or Ub-EKL and EKL substrate. The liberation of a fluorescent product within the linear range of the assay is monitored using a Perkin Elmer Envision fluorescence plate reader. Vehicle (2% [v/v] DMSO) and 10 mM N-ethylmaleimide (NEM) are included as controls.

Animal Models: CB-17 SCID-mice are subcutaneously inoculated with MM.1S, ARP-1, or RPMI-8226 cells in 100 μL of serum free RPMI-1640 medium. Formulation: P005091 is dissolved in 4% NMP(N-methyl-2-Pyrrolidone), 4% Tween-80, and 92% Milli-Q water at a final concentration of 2 mg/mL.