Background
AZD-5153 6-hydroxy-2-naphthoic acid (HNT salt) is a potent, selective, and orally available BET/BRD4 bromodomain inhibitor with pKi of 8.3 for BRD4. AZD-5153 inhibits the expression of Nuclear receptor binding SET domain protein 3 (NSD3) target genes. NSD3, via H3K36me2, acts as an epigenetic deregulator to facilitate the expression of oncogenesis-promoting genes.
Unlike previously described monovalent inhibitors, AZD5153 ligates two bromodomains in BRD4 simultaneously. AZD5153 treatment markedly affects transcriptional programs of MYC, E2F, and mTOR. Of note, mTOR pathway modulation is associated with cell line sensitivity to AZD5153. AZD5153 potently disrupts BRD4 foci in U2OS cells with an IC50 value of 1.7 nmol/L. AZD5153 efficiently downregulates MYC protein levels across the cell line panel irrespective of their sensitivity to AZD5153. AML, MM, and DLBCL cell lines are highly sensitive to AZD5153[1].
In vivo administration of AZD5153 leads to tumor stasis or regression in multiple xenograft models of acute myeloid leukemia, multiple myeloma, and diffuse large B-cell lymphoma. AZD5153 modulates MYC and HEXIM1 in AML xenograft tumors and human whole blood[1]. AZD5153 is administered orally to mice bearing MV-4-11 xenografts, and pharmacodynamic activity (intratumoral levels of c-Myc) is measured at 2, 4, and 8 h postdose. A considerable decrease in c-Myc expression is observed out to 8 h post dose at free plasma levels of compound <0.2 μM. This decrease in c-Myc expression after treatment with AZD5153 is consistent with other published BET inhibitors[2].
[1] Rhyasen GW, et al. Mol Cancer Ther. 2016, 15(11):2563-2574.
[2] Bradbury RH, et al. J Med Chem. 2016, 59(17):7801-17.
Protocol
Animal experiment: | Mice: Mice are treated with either vehicle (0.5% hydroxymethylcellulose, 0.1% Tween80) or AZD5153 by oral gavage mini-pump infusion. For continuous administration of AZD5153, compound is solubilized in 20% v/v DMSO/60% v/v HP-B-CD in water, loaded into a mini pump and implanted subcutaneously in mice. Tumor fragments collected are snap frozen or fixed in 10% buffered formalin. Blood samples are collected from the same mice and stabilized in EDTA. Plasma concentrations are determined by liquid chromatography/tandem mass spectrometry method[1]. |
参考文献: [1]. Rhyasen GW, et al. AZD5153: A Novel Bivalent BET Bromodomain Inhibitor Highly Active against Hematologic Malignancies. Mol Cancer Ther. 2016 Nov;15(11):2563-2574. |
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