(+)-JQ-1

(+)-JQ-1 (JQ1), a chemical probe, is a potent, specific, CNS-penetrant and reversible BET bromodomain inhibitor, with IC₅₀s of 77 and 33 nM for the first and second bromodomain (BRD4(1/2))^[1]. (+)-JQ-1 also activates autophagy^[2]. IC50 & Target:IC50: 77/33 nM (BRD4(1/2))^[1] In Vitro:(+)-JQ-1 represents a potent, highly specific and Kac competitive inhibitor for the BET family of bromodomains. (+)-JQ-1 (100 nM, 48 h) prompts squamous differentiation exhibited by cell spindling, flattening and increased expression of keratin. (+)-JQ-1 (250 nM) induces rapid expression of keratin in treated NMC 797 cells compared to (-)-JQ1 (250 nM) and vehicle controls, as determined by quantitative immunohistochemistry.(+)-JQ-1 (250 nM) elicits a time-dependent induction of strong (3+) keratin staining of treated NMC 797 cells, compared to (-)-JQ1 (250 nM)^[1]. De-repression of autophagy genes is observed almost immediately after (+)-JQ-1 addition^[2]. (+)-JQ-1 is a potent thienodiazepine inhibitor (K_d=90 nM) of the BET family coactivator protein BRD4, which is implicated in the pathogenesis of cancer via transcriptional control of the MYC oncogene. Dose-ranging studies of (+)-JQ-1 demonstrates potent inhibition of H4Kac4 binding with a IC₅₀ value of 10 nM for murine BRDT(1) and 11 nM for human BRDT(1)^[3]. In Vivo:Matched cohorts of mice with established tumors are randomized to treatment with (+)-JQ1 (50 mg/kg) or vehicle, administered by daily intraperitoneal injection. Prior to randomization, and after four days of therapy, mice are evaluated by FDG-PET imaging. A marked reduction in FDG uptake is observed with (+)-JQ1 treatment. Tumor-volume measurements confirm a reduction in tumor growth with JQ1 treatment. Pharmacokinetic studies of (+)-JQ1 are performed in CD1 mice following intravenous and oral administration. Mean plasma concentration-time profiles of (+)-JQ1 after intravenous dosing (5 mg/kg). The pharmacokinetic parameters for intravenous (+)-JQ1 demonstrate excellent drug exposure (AUC=2090 hr*ng/mL) and an approximately one hour half-life (T1/2). Mean plasma concentration-time profiles of (+)-JQ1 after oral dosing (10 mg/kg). The pharmacokinetic parameters for oral (+)-JQ1 demonstrate excellent oral bioavailability (F=49%), peak plasma concentration (C_max=1180 ng/mL) and drug exposure (AUC=2090 hr*ng/mL)^[1].