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

USP7:4.2 μM

P5091与Lenalidomide,HDAC抑制剂SAHA或Dexamethasone联用显示协同的抗MM活性.在动物肿瘤模型研究中,P005091具有良好的耐受性,抑制肿瘤生长并延长生存期.

P5091展现出针对USP7的强效,特异性和选择性去泛素化活性。相反,P5091不抑制测试的其他DUBs或其他家族半胱氨酸蛋白酶 (EC50>100 mM)。P5091降低HDM2和HDMX,上调p53和p21水平。总体而言,P5091-诱导的细胞毒性部分是通过HDM2-p21信号轴介导的,尽管P5091处理后p53上调,但P5091的细胞毒性不依赖于p53。P5091浓度依赖性抑制具有HA-UbVME标签的USP7。P5091剂量依赖性抑制USP7介导的超高分子量泛素链的裂解。而且,P5091抑制USP7-而非USP2-或USP8介导的-聚K48连接的泛素链的裂解。P5091抑制MM细胞中USP7去泛素化酶活性,不抑制蛋白酶活性。P5091克服骨髓间充质干细胞诱导的MM细胞生长。

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.