1303607-07-9

Ki: 0.88 nM (MDM2)

MI-773 potently induces expression of p53 and its downstream targets p21, MDM2, and induces phosphorylation of p53 (serine 392) in low passage primary human ACC cells. Notably, MI-773 induces a dose-dependent increase in the fraction of apoptotic ACC cells and in the fraction of cells in the G1 phase of cell cycle (P<0.05). Consequently, MI-773 causes apoptotic cell death. MI-773 is an advanced synthetic small molecule inhibitor, displays high binding affinity against MDM2 (K _d =8.2 nM).

MI-773 at 10 mg/kg modestly reduces the rate of tumor growth, whereas 100 mg/kg causes significant tumor regression. Control tumors reach an average of 1,000 mm ³ at 20 days of treatment, compare to an average volume of 600 mm ³ for the 10 mg/kg group and 30 mm ³ for the 100 mg/kg group. Kaplan-Meier analysis shows an increase in tumor failure, define as two times increase in tumor volume as compared to pretreatment volume (P=0.044), for vehicle-treated mice when compare to mice treated with 100 mg/kg MI-773.