ABSTRACT
Discovery of the activating mutation V617F in Janus Kinase 2 (JAK2(V617F)), a tyrosine kinase critically involved in receptor signaling, recently ignited interest in JAK2 inhibitor therapy as a treatment for myelofibrosis (MF). Herein, we describe the design and synthesis of a series of small molecule 4-aryl-2-aminopyrimidine macrocycles and their biological evaluation against the JAK family of kinase enzymes and FLT3. The most promising leads were assessed for their in vitro ADME properties culminating in the discovery of 21c, a potent JAK2 (IC(50) = 23 and 19 nM for JAK2(WT) and JAK2(V617F), respectively) and FLT3 (IC(50) = 22 nM) inhibitor with selectivity against JAK1 and JAK3 (IC(50) = 1280 and 520 nM, respectively). Further profiling of 21c in preclinical species and mouse xenograft and allograft models is described. Compound 21c (SB1518) was selected as a development candidate and progressed into clinical trials where it is currently in phase 2 for MF and lymphoma.
Subject(s)
Antineoplastic Agents/chemical synthesis , Bridged-Ring Compounds/chemical synthesis , Janus Kinase 2/antagonists & inhibitors , Lymphoma/drug therapy , Primary Myelofibrosis/drug therapy , Pyrimidines/chemical synthesis , fms-Like Tyrosine Kinase 3/antagonists & inhibitors , Adenosine Triphosphate/chemistry , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Binding Sites , Bridged-Ring Compounds/pharmacokinetics , Bridged-Ring Compounds/pharmacology , Cell Line, Tumor , Dogs , Drug Screening Assays, Antitumor , Humans , In Vitro Techniques , Mice , Mice, Nude , Microsomes, Liver/metabolism , Models, Molecular , Neoplasm Transplantation , Pyrimidines/pharmacokinetics , Pyrimidines/pharmacology , Rats , Solubility , Transplantation, Heterologous , Transplantation, HomologousABSTRACT
Thirty-six novel acylurea connected straight chain hydroxamates were designed and synthesized. Structure-activity relationships (SAR) were established for the length of linear chain linker and substitutions on the benzoylurea group. Compounds 5g, 5i, 5n, and 19 showed 10-20-fold enhanced HDAC1 potency compared to SAHA. In general, the cellular potency pIC(50) (COLO205) correlates with enzymatic potency pIC(50) (HDAC1). Compound 5b (SB207), a structurally simple and close analogue to SAHA, is more potent against HDAC1 and HDAC6 compared to the latter. As a representative example of this series, good in vitro enzymatic and cellular potency plus an excellent pharmacokinetic profile has translated into better efficacy than SAHA in both prostate cancer (PC3) and colon cancer (HCT116) xenograft models.
Subject(s)
Histone Deacetylase Inhibitors/chemical synthesis , Histone Deacetylase Inhibitors/pharmacology , Hydroxamic Acids/pharmacology , Urea/pharmacology , Animals , Cell Line, Tumor , Histone Deacetylase Inhibitors/chemistry , Humans , Hydroxamic Acids/chemistry , Kinetics , Mice , Structure-Activity Relationship , Transplantation, HeterologousABSTRACT
A series of alkenyl indazoles were synthesized and evaluated in Aurora kinase enzyme assays. Several promising leads were optimized for selectivity towards Aurora B. Excellent binding affinity and good selectivity were achieved with optimized compounds in isolated Aurora subfamily assays.
Subject(s)
Protein Kinase Inhibitors/chemical synthesis , Protein Serine-Threonine Kinases/antagonists & inhibitors , Aurora Kinases , Drug Evaluation, Preclinical , Models, Molecular , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/metabolism , Protein Kinase Inhibitors/pharmacology , Protein Serine-Threonine Kinases/metabolismABSTRACT
A series of N-hydroxy-1,2-disubstituted-1H-benzimidazol-5-yl acrylamides were designed and synthesized as novel HDAC inhibitors. General SAR has been established for the substituents at positions 1 and 2, as well as the importance of the ethylene group and its attachment to position 5. Optimized compounds are much more potent than SAHA in both enzymatic and cellular assays. A representative compound, 23 (SB639), has demonstrated antitumor activity in a colon cancer xenograft model.
Subject(s)
Acrylamides/chemical synthesis , Antineoplastic Agents/chemical synthesis , Benzimidazoles/chemical synthesis , Histone Deacetylase Inhibitors , Acrylamides/administration & dosage , Acrylamides/pharmacology , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/pharmacology , Benzimidazoles/administration & dosage , Benzimidazoles/pharmacology , Cell Line, Tumor , Crystallography, X-Ray , Drug Screening Assays, Antitumor/methods , Female , HCT116 Cells , Histone Deacetylases/metabolism , Humans , Mice , Mice, Nude , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
The Aurora family of serine/threonine kinases are mitotic regulators involved in centrosome duplication, formation of the bipolar mitotic spindle and the alignment of the chromosomes along the spindle. These proteins are frequently overexpressed in tumor cells as compared to normal cells and are therefore potential therapeutic oncology targets. An Aurora A high throughput screen revealed a promising sub-micromolar indazole-benzimidazole lead. Modification of the benzimidazole portion of the lead to a C2 linker with a phenyl ring was proposed to achieve novelty. Docking revealed that a conjugated linker was optimal and the resulting compounds were equipotent with the lead. Further structure-guided optimization of substituents on the 5 & 6 position of the indazole led to single digit nanomolar potency. The homology between the Aurora A & Aurora B kinase domains is 71% but their binding sites only differ at residues 212 & 217 (Aurora A numbering). However interactions with only the latter residue may be used for obtaining selectivity. An analysis of published Aurora A and Aurora B X-ray structures reveals subtle differences in the shape of the binding sites. This was exploited by introduction of appropriately sized substituents in the 4 & 6 position of the indazole leading to Aurora B selective inhibitors. Finally we calculate the conformational energy penalty of the putative bioactive conformation of our inhibitors and show that this property correlates well with the Aurora A binding affinity.
