P22077

P22077 is a potent and selective ubiquitin-specific protease 7 (USP7) inhibitor. P22077 stabilized p53 by inducing HDM2 protein degradation in NB cells. P22077 also significantly augmented the cytotoxic effects of doxorubicin (Dox) and etoposide (VP-16) in NB cells with an intact USP7-HDM2-p53 axis but not in NB cells with mutant p53 or without human homolog of MDM2 (HDM2) expression. In an in vivo orthotopic NB mouse model, P22077 significantly inhibited the xenograft growth of three NB cell lines. P22077 treatment of U2OS cells during release from G1/S arrest induces with hydroxyurea resulted in a dose-dependent loss of claspin protein and a concomitant decrease in phospho Serine 317 Chk1.