P 22077 is a cell-permeable ubiquitin-specific protease 7 (USP7) inhibitor with an EC₅₀ of 8.01 μM. It also inhibits USP47 with an EC₅₀ of 8.74 μM. IC50 & Target: EC50: 8.01 μM (USP7), 8.74 μM (USP47)^[1] In Vitro: P 22077 is an inhibitor of USP7 and DUB USP47, with EC₅₀s of 8.01 μM and 8.74 μM, respectively. P 22077 (15-45 μM) inhibits a much smaller subset of DUBs. P 22077 (25 μM) causes DUBs inhibition in HEK293T cells^[1]. P 22077 (0-20 μM) greatly reduces the cell viability of Neuroblastoma (NB) cells including IMR-32, NGP, CHLA-255, and SH-SY5Y cells but without NB-19 and SK-N-AS cells. P 22077 (10 μM) increases p53 activity and induces apoptosis in p53 wild-type and HDM2-expressing NB cells. P 22077 (5 μM) enhances the cytotoxic effect of Dox and VP-16 on NB cells, and enhances Dox- and VP-16-induced p53-mediated apoptosis^[2]. In Vivo: P 22077 (15 mg/kg, i.p. 21 days) shows potent antitumor activities in an xenograft mouse model bearing IMR-32-derived tumors; P 22077 also exhibits antitumor effects after treatment at 10 mg/kg for 14 days in mice bearing SH-SY5Y-derived tumors, and at 20 mg/kg for 12 days in mice bearing NGP-derived tumors^[2].