Novel Allosteric Mechanism of Dual p53/MDM2 and p53/MDM4 Inhibition by a Small Molecule.

Restoration of the p53 tumor suppressor for personalised cancer therapy is a promising treatment strategy. However, several high-affinity MDM2 inhibitors have shown substantial side effects in clinical trials. Thus, elucidation of the molecular mechanisms of action of p53 reactivating molecules with alternative functional principle is of the utmost importance.

Inhibition of glycolytic enzymes mediated by pharmacologically activated p53: targeting Warburg effect to fight cancer.

Unique sensitivity of tumor cells to the inhibition of glycolysis is a good target for anticancer therapy. Here, we demonstrate that the pharmacologically activated tumor suppressor p53 mediates the inhibition of glycolytic enzymes in cancer cells in vitro and in vivo. We showed that p53 binds to the promoters of metabolic genes and represses their expression, including glucose transporters SLC2A12 (GLUT12) and SLC2A1 (GLUT1).

Learning-induced lateralized activation of the MAPK/ERK cascade in identified neurons of the food-aversion network in the mollusk Helix lucorum.

The MAPK/ERK pathway plays an important role in the regulation of gene expression during memory formation both in vertebrates and invertebrates. In the mollusk Helix lucorum, serotonin induces activation of MAPK/ERK in the central nervous system (CNS) upon food aversion learning. Such learning depends on a neuronal network in which specialized neurons play distinct roles so that they may exhibit different activation levels of the MAPK/ERK pathway.

Rescue of the apoptotic-inducing function of mutant p53 by small molecule RITA.

Expression of mutant p53 correlates with poor prognosis in many tumors, therefore strategies aimed at reactivation of mutant p53 are likely to provide important benefits for treatment of tumors that are resistant to chemotherapy and radiotherapy. We have previously identified and characterized a small molecule RITA which binds p53 and induces a conformational change which prevents the binding of p53 to several inhibitors, including its own destructor MDM2. In this way, RITA rescues the tumor suppression function of wild type p53.

Ablation of key oncogenic pathways by RITA-reactivated p53 is required for efficient apoptosis.

Targeting "oncogene addiction" is a promising strategy for anticancer therapy. We report a potent inhibition of crucial oncogenes by p53 upon reactivation by small-molecule RITA in vitro and in vivo. RITA-activated p53 unleashes the transcriptional repression of antiapoptotic proteins Mcl-1, Bcl-2, MAP4, and survivin; blocks the Akt pathway on several levels; and downregulates c-Myc, cyclin E, and beta-catenin.