An activator of p53; increases expression of p53 and the p53 target DR5 in wild-type and p53-knockout HCT116 colon adenocarcinoma cells; selective for p53, having no effect on p73 expression in HCT116 cells (2 μM); increases p53 expression, decreases expression of the p53 suppressor MDMX, and reduces viability in a panel of breast cancer cell lines (0.5 μM); reduces growth of AMC-HN9 HNC cells in vitro and in vivo when administered alone or in combination with cisplatin in a mouse xenograft model (70 mg/kg)