P5091

P5091 (P005091) is a cell permeable, potent and specific inhibitor of deubiquitylating enzyme USP7, which induces elevated p53 and apoptosis in cancer cell lines. P5091-induced cytotoxicity is mediated in part via HDM2-p21 signaling axis and although p53 is upregulated in response to P5091 treatment, the cytotoxic activity of P5091 is not dependent on p53. P5091 induces HDM2 polyubiquitylation and accelerates degradation of HDM2. P5091 displays antiangiogenic activity in vivo. P5091 is well tolerated, inhibits tumor growth and prolongs survival in animal models of cancer.