NSC 207895 is an inhibitor of the p53-binding protein MDMX. It decreases MDMX promoter activity in a reporter assay using HT-1080 cells in a concentration-dependent manner. NSC 207895 (5 μmol/L) decreases the expression and protein levels of MDMX and increases the expression of the p53 target gene CDKN1 (p21) in MCF-7 cells overexpressing MDMX. It also increases the expression of the pro-apoptotic genes PUMA, Bax, and PIG3. NSC 207895 (5 μmol/L) induces apoptosis and decreases cell viability in MCF-7 cells in a p53-dependent manner. It also induces p53-independent apoptosis in wild-type, mutated, and truncated p53 Ewing sarcoma cell lines (IC50s = 98.9-1,613, 236-299, and 121-396 nM, respectively) selectively over wild-type and p53-null osteosarcoma cells (IC50s = 3,690-5,416 and 2,143 nM, respectively).
