[CAS NO. 63208-82-2]  Pifithrin-α (PFTα) HBr

Pifithrin-α inhibits p53-dependent transactivation of p53-responsive genes in ConA cells. Pifithrin-α (10 μM) inhibits apoptotic death of C8 cells induced by Dox, etoposide, Taxol, cytosine arabinoside. Pifithrin-α inhibits p53-dependent growth arrest of human diploid fibroblasts in response to DNA damage but has no effect on p53-deficient fibroblasts. Pifithrin-α may modulate the nuclear import or export (or both) of p53 or may decrease the stability of nuclear p53. Pifithrin-α (100-200 nM) completely suppresses the camptothecin-induced increase in the level of p53 DNA binding as well as the p53-responsive gene Bax in hippocampal cell. Pifithrin-α also decreases the basal level of p53 DNA-binding activity. Pifithrin-α (200 nM) protects cultured hippocampal neurons against death induced by DNA-damaging agents. Pifithrin-α (200 μM) stabilizes mitochondrial function, suppresses caspase activation and protects cultured hippocampal neurons against death induced by glutamate and amyloid β-peptide. Pifithrin α, in addition to p53, can suppress heat shock and glucocorticoid receptor signaling but has no effect on nuclear factor-kappaB signaling. Pifithrin α (10 μM) reduces activation of heat shock transcription factor (HSF1) and increases cell sensitivity to heat. Pifithrin α (10 μM) reduces activation of glucocorticoid receptor and rescues mouse thymocytes from apoptotic death after dexamethasone treatment in HeLa cells. PFTalpha blocks p53-mediated induction of p21/Waf-1 in human embryonic kidney cells. PFTalpha does, however, cause a left shift in the dexamethasone dose response curve by increasing intracellular dexamethasone concentration.