AZ 960

AZ960 is a novel inhibitor of janus-associated kinases (JAKs) that exhibits a potent inhibition against janus kinase 2 (JAK2) with the value of inhibition constant of K_i of 0.45 nmol/L. It also exhibits a lesser inhibitory effects against other JAKs family members, including JAK1, JAK3 and TYK2 as well as other kinases, including TrkA, Aurora A and FAK, with 50% inhibition concentration IC₅₀ of around 0.1 μmol/L. In recent studies, AZ960 demonstrates potential anti-cancer activity against adult T-cell leukemia (ATL), an aggressive malignancy of CD4+ T lymphocytes, by effectively inducing growth arrest and apoptosis in human T-cell lumphotropic virus type 1 (HTLV-1) infected T cells.

Reference

Yang J, Ikezoe T, Nishioka C, Furihata M, Yokoyama A. AZ960, a novel Jak2 inhibitor, induces growth arrest and apoptosis in adult T-cell leukemia cells. Mol Cancer Ther. 2010;9(12):3386-3395.

Discovery and antiparasitic activity of AZ960 as a Trypanosoma brucei ERK8 inhibitor.[Pubmed:27519462]

Bioorg Med Chem. 2016 Oct 1;24(19):4647-4651.

Human African trypanosomiasis (HAT) is a lethal, vector-borne disease caused by the parasite Trypanosoma brucei. Therapeutic strategies for this neglected tropical disease suffer from disadvantages such as toxicity, high cost, and emerging resistance. Therefore, new drugs with novel modes of action are needed. We screened cultured T. brucei against a focused kinase inhibitor library to identify promising bioactive compounds. Among the ten hits identified from the phenotypic screen, AZ960 emerged as the most promising compound with potent antiparasitic activity (IC50=120nM) and was shown to be a selective inhibitor of an essential gene product, T. brucei extracellular signal-regulated kinase 8 (TbERK8). We report that AZ960 has a Ki of 1.25muM for TbERK8 and demonstrate its utility in establishing TbERK8 as a potentially druggable target in T. brucei.

AZ960, a novel Jak2 inhibitor, induces growth arrest and apoptosis in adult T-cell leukemia cells.[Pubmed:21159615]

Mol Cancer Ther. 2010 Dec;9(12):3386-95.

Adult T-cell leukemia/lymphoma (ATL) is a highly aggressive disease in which the Jak2/Stat5 pathway is constitutively activated. This study found that AZ960, a novel inhibitor of Jak2 kinase, effectively induced growth arrest and apoptosis of human T-cell lymphotropic virus type 1, HTLV-1-infected T cells (MT-1 and MT-2) in parallel with downregulation of the phosphorylated forms of Jak2 and Bcl-2 family proteins including Bcl-2 and Mcl-1. Interestingly, AZ960 increased levels of Bcl-xL in MT-1 and MT-2 cells in association with accumulation of cAMP response element-binding protein bound to the Bcl-xL promoter as measured by chromatin immunoprecipitation assay. Importantly, genetic inhibition of Bcl-xL by a small interfering RNA potentiated antiproliferative effects of AZ960 in MT-1 cells. Taken together, Jak2 is an attractive molecular target for treatment of ATL. Concomitant blockade of Jak2 and Bcl-xL may be a promising treatment strategy for this lethal disease.

Expression of p-JAK2 predicts clinical outcome and is a potential molecular target of acute myelogenous leukemia.[Pubmed:21207414]

Int J Cancer. 2011 Nov 15;129(10):2512-21.

Our study determined if Janus kinase 2 (JAK2) was activated in acute myelogenous leukemia (AML; n = 77, excluding acute promyelocytic leukemia) by immunohistochemistry (IHC) using a phosphor-specific antibody against JAK2. p-JAK2 was detectable in all cases, although its levels varied between patient samples (high levels, n = 31; low levels, n = 46). The quantification of levels of p-JAK2 by IHC was well correlated with that assessed by Western blot analyses and fluorescence-activated cell sorting (FACS). Levels of p-JAK2 were directly correlated with high white blood cell count (52.3 x 10(3) /L in patients with high p-JAK2 vs. 28.3 x 10(3) /L in patients with low p-JAK2, p < 0.01) and were inversely correlated with complete remission rates (45% in patients with high p-JAK2 vs. 78% in patients with low p-JAK2, p < 0.003). In addition, multivariate analysis confirmed that high levels of p-JAK2 remained a significant factor for overall survival (hazard ratio = 2.213; 95% confidence interval, 1.212-4.041, p = 0.023). Moreover, we found that AZ960, a novel and specific inhibitor of the JAK2 kinase, potently inhibited the clonogenic growth and induced apoptosis of freshly isolated AML cells from patients in association with cleavage of caspase 3 and downregulation of anti-apoptotic Bcl-xL proteins. Taken together, JAK2 may be a promising molecular target for treatment of AML.

Effects of the JAK2 inhibitor, AZ960, on Pim/BAD/BCL-xL survival signaling in the human JAK2 V617F cell line SET-2.[Pubmed:18775810]

J Biol Chem. 2008 Nov 21;283(47):32334-43.

The Janus-associated kinase 2 (JAK2) V617F mutation is believed to play a critical role in the pathogenesis of polycythemia vera, essential thrombocythemia, and idiopathic myelofibrosis. We have characterized a novel small molecule JAK2 inhibitor, AZ960, and used it as a tool to investigate the consequences of JAK2 V617F inhibition in the SET-2 cell line. AZ960 inhibits JAK2 kinase with a K(i) of 0.00045 microm in vitro and treatment of TEL-JAK2 driven Ba/F3 cells with AZ960 blocked STAT5 phosphorylation and potently inhibited cell proliferation (GI(50)=0.025 microm). AZ960 demonstrated selectivity for TEL-JAK2-driven STAT5 phosphorylation and cell proliferation when compared with cell lines driven by similar fusions of the other JAK kinase family members. In the SET-2 human megakaryoblastic cell line, heterozygous for the JAK2 V617F allele, inhibition of JAK2 resulted in decreased STAT3/5 phosphorylation and inhibition of cell proliferation (GI(50)=0.033 microm) predominately through the induction of mitochondrial-mediated apoptosis. We provide evidence that JAK2 inhibition induces apoptosis by direct and indirect regulation of the anti-apoptotic protein BCL-xL. Inhibition of JAK2 blocked BCL-XL mRNA expression resulting in a reduction of BCL-xL protein levels. Additionally, inhibition of JAK2 resulted in decreased PIM1 and PIM2 mRNA expression. Decreased PIM1 mRNA corresponded with a decrease in Pim1 protein levels and inhibition of BAD phosphorylation at Ser(112). Finally, small interfering RNA-mediated suppression of BCL-xL resulted in apoptotic cell death similar to the phenotype observed following JAK2 inhibition. These results suggest a model in which JAK2 promotes cell survival by signaling through the Pim/BAD/BCL-xL pathway.