In vitro study | RG7112 is a potent and selective MDM2 antagonist, a member of the Nutlin family, and is currently in Phase I clinical studies. RG7112 binds MDM2 with high affinity (K D of 10.7 nM), blocking its interaction with p53 in vitro. The crystal structure of the RG7112-MDM2 complex indicates that the small molecule binds to the p53 pocket of MDM2, mimicking the interaction of important p53 amino acid residues. Treatment of cancer cells expressing wild-type p53 by RG7112 activates the p53 pathway, leading to cell cycle arrest and apoptosis. RG7112 exhibited potent anti-tumor activity against a panel of tumor cell lines. However, their anti-apoptotic activity was quite different, with optimal responses observed in MDM2 gene-amplified osteosarcoma cells. |