Pacritinib (SB1518), a JAK2/FLT3 inhibitor for the treatment of acute myeloid leukemia

FMS-like tyrosine kinase 3 (FLT3) is the most commonly mutated gene found in acute myeloid leukemia (AML) patients and its activating mutations have been proven to be a negative prognostic marker for clinical outcome. Pacritinib (SB1518) is a tyrosine kinase inhibitor (TKI) with equipotent activity against FLT3 (IC50=22 n) and Janus kinase 2 (JAK2, IC50=23 n). Pacritinib inhibits FLT3 phosphorylation and downstream STAT, MAPK and PI3 K signaling in FLT3-internal-tandem duplication (ITD), FLT3-wt cells and primary AML blast cells. Oral administration of pacritinib in murine models of FLT3-ITD-driven AML led to significant inhibition of primary tumor growth and lung metastasis. Upregulation of JAK2 in FLT3-TKI-resistant AML cells was identified as a potential mechanism of resistance to selective FLT3 inhibition. This resistance could be overcome by the combined FLT3 and JAK2 activities of pacritinib in this cellular model. Our findings provide a rationale for the clinical evaluation of pacritinib in AML including patients resistant to FLT3-TKI therapy

The oral HDAC inhibitor pracinostat (SB939) is efficacious and synergistic with the JAK2 inhibitor pacritinib (SB1518) in preclinical models of AML

Acute myeloid leukemia (AML) is currently treated with aggressive chemotherapy that is not well tolerated in many elderly patients, hence the unmet medical need for effective therapies with less toxicity and better tolerability. Inhibitors of FMS-like tyrosine kinase 3 (FLT3), JAK2 and histone deacetylase inhibitors (HDACi) have been tested in clinical studies, but showed only moderate single-agent activity. High efficacy of the HDACi pracinostat treating AML and synergy with the JAK2/FLT3 inhibitor pacritinib is demonstrated. Both compounds inhibit JAK-signal transducer and activator of transcription (STAT) signaling in AML cells with JAK2V617F mutations, but also diminish FLT3 signaling, particularly in FLT3-ITD (internal tandem duplication) cell lines. In vitro, this combination led to decreased cell proliferation and increased apoptosis. The synergy translated in vivo in two different AML models, the SET-2 megakaryoblastic AML mouse model carrying a JAK2V617F mutation, and the MOLM-13 model of FLT3-ITD-driven AML. Pracinostat and pacritinib in combination showed synergy on tumor growth, reduction of metastases and synergistically decreased JAK2 or FLT signaling, depending on the cellular context. In addition, several plasma cytokines/growth factors/chemokines triggered by the tumor growth were normalized, providing a rationale for combination therapy with an HDACi and a JAK2/FLT3 inhibitor for the treatment of AML patients, particularly those with FLT3 or JAK2 mutations

Epigenetic modulators as therapeutic targets in prostate cancer

Prostate cancer is one of the most common non-cutaneous malignancies among men worldwide. Epigenetic aberrations, including changes in DNA methylation patterns and/or histone modifications, are key drivers of prostate carcinogenesis. These epigenetic defects might be due to deregulated function and/or expression of the epigenetic machinery, affecting the expression of several important genes. Remarkably, epigenetic modifications are reversible and numerous compounds that target the epigenetic enzymes and regulatory proteins were reported to be effective in cancer growth control. In fact, some of these drugs are already being tested in clinical trials. This review discusses the most important epigenetic alterations in prostate cancer, highlighting the role of epigenetic modulating compounds in pre-clinical and clinical trials as potential therapeutic agents for prostate cancer management.info:eu-repo/semantics/publishedVersio

Modulation of the interleukin-6 receptor subunit glycoprotein 130 complex and its signaling by LMO4 interaction

10.1074/jbc.M500175200Journal of Biological Chemistry2801312747-12757JBCH

First-in-Human, Healthy Volunteers Integrated Protocol of ETC-206, an Oral Mnk 1/2 Kinase Inhibitor Oncology Drug

10.1111/cts.12678Clinical and Translational Science13157-6

Phase I and pharmacodynamic study of an orally administered novel inhibitor of histone deacetylases, SB939, in patients with refractory solid malignancies

10.1093/annonc/mdq784Annals of Oncology22112516-2522ANON