Pifithrin-µ

Pifithrin-μ (PFT-μ) is an inhibitor of p53-mediated apoptosis, preventing p53 binding to Bcl-xL and Bcl-2 at the mitochondria without affecting p53 transactivational activities. In vitro, PFT-μ binds both p53 (Kd = 0.82 mM) and Bcl-xL (Kd = 0.80 mM). It reduces p53-mediated apoptosis induced by γ-radiation in mouse thymocytes in vitro and protects mice from doses of radiation that cause lethal hematopoietic syndrome. At 25 μM, PFT-μ reduces apoptosis triggered by nutlin-3, which inhibits MDM2/p53 binding and potentiates p53-mediated growth arrest and apoptosis.