Pifusertib (hydrochloride)

Pifusertib (TAS-117) hydrochloride is a potent, selective, orally active allosteric Akt inhibitor (with IC₅₀s of 4.8, 1.6, and 44 nM for Akt1, 2, and 3, respectively). Pifusertib hydrochloride triggers anti-myeloma activities and enhances fatal endoplasmic reticulum (ER) stress induced by proteasome inhibition. Pifusertib hydrochloride induces apoptosis and autophagy^[1]. In Vitro: Pifusertib (1 μM; 6 hours) blocks basal phosphorylation of Akt and downstream p-FKHR/FKHRL1 in MM cells with high baseline p-Akt^[1].
Pifusertib (0-10 μM; 72 hours) selectively inhibits Akt and induces cytotoxicity in MM cells with high baseline phosphorylation of Akt^[1].
Pifusertib abrogates the cytoprotective effect of the bone marrow microenvironment associated with Akt inhibition in both MM cells and BMSCs. Pifusertib enhances Carfilzomib-induced cytotoxicity and fatal ER stress in MM cells. Pifusertib (0.5, 1 μM) triggers G0/G1 arrest followed by apoptosis, associated with induction of autophagy and endoplasmic reticulum stress response^[1].
Pifusertib enhances bortezomib-induced cytotoxicity, associated with increased CHOP (a fatal ER-stress marker) and PARP cleavage and blockade of bortezomib-induced p-Akt, suggesting that Pifusertib augments Bortezomib-induced ER stress and apoptotic signaling^[1]. In Vivo: Pifusertib (12-16 mg/kg; p.o.; daily for 5 days a week, 21 days) inhibits tumor growth in murine xenograft models of human MM^[1].
Pifusertib enhances bortezomib-induced MM cytotoxicity in vivo^[1].