STAT5 Inhibitor III, Pimozide

Toxicity: Regulatory Review (Z)

A cell-permeable and orally available diphenylbutylpiperidine class of psychotropic drug with antagonistic activity against DAT (dopamine transporter) as well as several postsynaptic receptors, including D₁, D₂, D₃, D₄, α₁-/α₂-adrenergic, and 5-HT_2A receptors. In addition to its antipsychotic property, Pimozide is shown to inhibit the constitutive STAT5 Tyr694 phosphorylation (5 to 10 µM for 3h) and transcription activity (5 µM for 18 h) in Bcr-Abl+ K562 and KU812 cultures, while exhibiting little activity against IFNα-stimulated STAT1 phosphorylation or LIF-stimulated STAT3 phosphorylation in K562 cells (10 µM 1 h pretreatment). The mechanism of STAT5 inhibition is currently unknown and Primozide is reported to exhibit little inhibitory activity against cellular Bcr-Abl autophosphorylation or the kinase activities of Abl1 (Wt & T315I), Hck, Lyn A/B, and Src (≤7%) in cell-free kinase assays. Shown to exhibit selective antiproliferative activity against K562, KU812, and primary bone marrow mononuclear cells from CML patients (by >80%; 10 µM for 48 h), but not peripheral blood mononuclear cells from healthy individuals, due to G0/G1 cell cycle arrest and apoptosis induction. Acts as a selective and non-competitive inhibitor of human USP1/UAF1 and USP7 activities (IC₅₀ = 2 and 47 µM, respectively) with no effect on UCH-L1 and UCH-L3 (IC₅₀ >500 µM).

Chen, J., et al. 2011. Chem. Biol18, 1390.
Nelson, E.A., et al. 2011. Blood117, 3421.

Packaged under inert gas

Following reconstitution, aliquot and freeze (-20°C). Stock solutions ar stable for up to 6 months at -20°C.

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