RESUMO
Background: The mitotic kinesin, KIF18A, is required for proliferation of cancer cells that exhibit chromosome instability (CIN), implicating it as a promising target for treatment of a subset of aggressive tumor types. Determining regions of the KIF18A protein to target for inhibition will be important for the design and optimization of effective small molecule inhibitors. Methods: In this study, we used cultured cell models to investigate the effects of mutating S284 within the alpha-4 helix of KIF18A, which was previously identified as a phosphorylated residue. Results: Mutations in S284 cause relocalization of KIF18A from the plus-ends of spindle microtubules to the spindle poles. Furthermore, KIF18A S284 mutants display loss of KIF18A function and fail to support proliferation in CIN tumor cells. Interestingly, similar effects on KIF18A localization and function were seen after treatment of CIN cells with KIF18A inhibitory compounds that are predicted to interact with residues within the alpha-4 helix. Conclusion: These data implicate the KIF18A alpha-4 helix as an effective target for inhibition and demonstrate that small molecules targeting KIF18A selectively limit CIN tumor cell proliferation and result in phenotypically similar effects on mitosis at the single cell level compared to genetic perturbations.
RESUMO
The mitotic kinesin, KIF18A, is required for proliferation of cancer cells that exhibit chromosome instability (CIN), implicating it as a promising target for treatment of a subset of aggressive tumor types. Determining regions of the KIF18A protein to target for inhibition will be important for the design and optimization of effective small molecule inhibitors. In this study, we investigated the effects of mutating S284 within the alpha-4 helix of KIF18A, which was previously identified as a phosphorylated residue. Mutations in S284 cause relocalization of KIF18A from the plus-ends of spindle microtubules to the spindle poles. Furthermore, KIF18A S284 mutants display loss of KIF18A function and fail to support proliferation in CIN tumor cells. Interestingly, similar effects on KIF18A localization and function were seen after treatment of CIN cells with KIF18A inhibitory compounds that are predicted to interact with residues within the alpha-4 helix. These data implicate the KIF18A alpha-4 helix as an effective target for inhibition and demonstrate that small molecules targeting KIF18A selectively limit CIN tumor cell proliferation and result in phenotypically similar effects on mitosis at the single cell level compared to genetic perturbations.
RESUMO
Structure-based methods were used to design a potent and highly selective group II p21-activated kinase (PAK) inhibitor with a novel binding mode, compound 17. Hydrophobic interactions within a lipophilic pocket past the methionine gatekeeper of group II PAKs approached by these type I 1/2 binders were found to be important for improving potency. A structure-based hypothesis and strategy for achieving selectivity over group I PAKs, and the broad kinome, based on unique flexibility of this lipophilic pocket, is presented. A concentration-dependent decrease in tumor cell migration and invasion in two triple-negative breast cancer cell lines was observed with compound 17.
Assuntos
Alcinos/síntese química , Antineoplásicos/síntese química , Benzimidazóis/síntese química , Pirimidinas/síntese química , Quinases Ativadas por p21/antagonistas & inibidores , Alcinos/química , Alcinos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Benzimidazóis/química , Benzimidazóis/farmacologia , Sítios de Ligação , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Pirimidinas/química , Pirimidinas/farmacologia , Relação Estrutura-Atividade , Neoplasias de Mama Triplo Negativas , Quinases Ativadas por p21/químicaRESUMO
A therapeutic rationale is proposed for the treatment of inflammatory diseases, such as psoriasis and inflammatory bowel diseases (IBD), by selective targeting of TYK2. Hit triage, following a high-throughput screen for TYK2 inhibitors, revealed pyridine 1 as a promising starting point for lead identification. Initial expansion of 3 separate regions of the molecule led to eventual identification of cyclopropyl amide 46, a potent lead analog with good kinase selectivity, physicochemical properties, and pharmacokinetic profile. Analysis of the binding modes of the series in TYK2 and JAK2 crystal structures revealed key interactions leading to good TYK2 potency and design options for future optimization of selectivity.
Assuntos
Inibidores de Proteínas Quinases/farmacologia , TYK2 Quinase/antagonistas & inibidores , Relação Dose-Resposta a Droga , Humanos , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Relação Estrutura-Atividade , TYK2 Quinase/metabolismoRESUMO
The advancement of a series of ligand efficient 2-amino-[1,2,4]triazolo[1,5-a]pyridines, initially identified from high-throughput screening, to a JAK2 inhibitor with pharmacodynamic activity in a mouse xenograft model is disclosed.
Assuntos
Amitrol (Herbicida)/química , Amitrol (Herbicida)/uso terapêutico , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Janus Quinase 2/antagonistas & inibidores , Pirimidinas/química , Pirimidinas/uso terapêutico , Triazóis/química , Triazóis/uso terapêutico , Amitrol (Herbicida)/farmacologia , Animais , Antineoplásicos/farmacologia , Cristalografia por Raios X , Humanos , Janus Quinase 2/química , Janus Quinase 2/metabolismo , Camundongos , Modelos Moleculares , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Neoplasias/patologia , Pirimidinas/farmacologia , Relação Estrutura-Atividade , Triazóis/farmacologiaRESUMO
Herein we report our lead optimization effort to identify potent, selective, and orally bioavailable TYK2 inhibitors, starting with lead molecule 3. We used structure-based design to discover 2,6-dichloro-4-cyanophenyl and (1R,2R)-2-fluorocyclopropylamide modifications, each of which exhibited improved TYK2 potency and JAK1 and JAK2 selectivity relative to 3. Further optimization eventually led to compound 37 that showed good TYK2 enzyme and interleukin-12 (IL-12) cell potency, as well as acceptable cellular JAK1 and JAK2 selectivity and excellent oral exposure in mice. When tested in a mouse IL-12 PK/PD model, compound 37 showed statistically significant knockdown of cytokine interferon-γ (IFNγ), suggesting that selective inhibition of TYK2 kinase activity might be sufficient to block the IL-12 pathway in vivo.
Assuntos
4-Aminopiridina/análogos & derivados , 4-Aminopiridina/síntese química , Aminopiridinas/síntese química , Benzamidas/síntese química , TYK2 Quinase/antagonistas & inibidores , 4-Aminopiridina/farmacocinética , 4-Aminopiridina/farmacologia , Administração Oral , Aminopiridinas/farmacocinética , Aminopiridinas/farmacologia , Animais , Benzamidas/farmacocinética , Benzamidas/farmacologia , Disponibilidade Biológica , Cristalografia por Raios X , Interferon gama/antagonistas & inibidores , Interferon gama/biossíntese , Interleucina-12/metabolismo , Janus Quinase 1/antagonistas & inibidores , Janus Quinase 2/antagonistas & inibidores , Janus Quinase 3/antagonistas & inibidores , Camundongos , Microssomos Hepáticos/metabolismo , Modelos Moleculares , Ligação Proteica , Ratos , Fator de Transcrição STAT4/antagonistas & inibidores , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Herein we report on the structure-based discovery of a C-2 hydroxyethyl moiety which provided consistently high levels of selectivity for JAK1 over JAK2 to the imidazopyrrolopyridine series of JAK1 inhibitors. X-ray structures of a C-2 hydroxyethyl analogue in complex with both JAK1 and JAK2 revealed differential ligand/protein interactions between the two isoforms and offered an explanation for the observed selectivity. Analysis of historical data from related molecules was used to develop a set of physicochemical compound design parameters to impart desirable properties such as acceptable membrane permeability, potent whole blood activity, and a high degree of metabolic stability. This work culminated in the identification of a highly JAK1 selective compound (31) exhibiting favorable oral bioavailability across a range of preclinical species and robust efficacy in a rat CIA model.
Assuntos
Antirreumáticos/síntese química , Compostos Heterocíclicos com 3 Anéis/síntese química , Imidazóis/síntese química , Janus Quinase 1/antagonistas & inibidores , Janus Quinase 2/antagonistas & inibidores , Piridinas/síntese química , Pirróis/síntese química , Administração Oral , Animais , Antirreumáticos/química , Antirreumáticos/farmacologia , Artrite Experimental/tratamento farmacológico , Artrite Experimental/etiologia , Disponibilidade Biológica , Permeabilidade da Membrana Celular , Colágeno , Cristalografia por Raios X , Cães , Haplorrinos , Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Imidazóis/química , Imidazóis/farmacologia , Isoenzimas/antagonistas & inibidores , Isoenzimas/química , Janus Quinase 1/química , Janus Quinase 2/química , Células Madin Darby de Rim Canino , Microssomos Hepáticos/metabolismo , Modelos Moleculares , Estrutura Molecular , Piridinas/química , Piridinas/farmacologia , Pirróis/química , Pirróis/farmacologia , Ratos , EstereoisomerismoRESUMO
Herein we report the discovery of the C-2 methyl substituted imidazopyrrolopyridine series and its optimization to provide potent and orally bioavailable JAK1 inhibitors with selectivity over JAK2. The C-2 methyl substituted inhibitor 4 exhibited not only improved JAK1 potency relative to unsubstituted compound 3 but also notable JAK1 vs JAK2 selectivity (20-fold and >33-fold in biochemical and cell-based assays, respectively). Features of the X-ray structures of 4 in complex with both JAK1 and JAK2 are delineated. Efforts to improve the in vitro and in vivo ADME properties of 4 while maintaining JAK1 selectivity are described, culminating in the discovery of a highly optimized and balanced inhibitor (20). Details of the biological characterization of 20 are disclosed including JAK1 vs JAK2 selectivity levels, preclinical in vivo PK profiles, performance in an in vivo JAK1-mediated PK/PD model, and attributes of an X-ray structure in complex with JAK1.