Figure 7.

Inhibition of USP7 leads to MM cell apoptosis by inducing Maf protein degradation. A, chemical structure of the USP7-specific inhibitor P5091. B, RPMI-8226 and LP1 cells were treated with P5091 for 24 h, followed by IP/IB assays. C, RPMI-8226 and OCI-MY5 cells were treated with P5091 for 24 h, followed by IP/IB assay as indicated. D, MARE.Luci reporter plasmid was co-transfected into HEK293T cells with USP7 and MafB or c-Maf. Twenty four hours later, cells were treated with P5091 for another 24 h before being subjected to luciferase assay. E–G, RPMI-8226 and LP1 cells (E), OCI-MY5 (F), and KMS11 (G) cells were treated with P5091 for 24 h, followed by cell lysate preparations and IB assays against specific antibodies as indicated. H, KMS11, OCI-MY5, and RPMI-8226 cells were treated by P5091 for 24 h, followed by annexin V–FITC and propidium iodide staining and flow cytometric analysis.