RESUMO
Structure-guided design led to the discovery of novel chemical scaffolds for B-Raf inhibitors. Both type I and type II kinase inhibitors have been explored and lead compounds with good potency and excellent selectivity have been identified.
Assuntos
Desenho de Fármacos , Inibidores Enzimáticos/síntese química , Isoindóis/síntese química , Ftalazinas/síntese química , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Benzenossulfonatos/química , Benzenossulfonatos/farmacologia , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Imidazóis/química , Imidazóis/farmacologia , Isoindóis/química , Isoindóis/farmacologia , Modelos Moleculares , Estrutura Molecular , Niacinamida/análogos & derivados , Compostos de Fenilureia , Ftalazinas/química , Ftalazinas/farmacologia , Piridinas/química , Piridinas/farmacologia , Sorafenibe , Relação Estrutura-AtividadeRESUMO
In continuation of our efforts toward hit identification and optimization for a B-Raf kinase project, we have employed a scaffold hopping strategy. The original HTS hit scaffold pyrazolo[1,5-a]pyrimidine was replaced with different thienopyrimidine and thienopyridine scaffolds to append the optimal pharmacophore moieties in order to generate novel B-raf kinase inhibitors with desirable potency and properties. This strategy led to the identification of additional lead compound 11b which had good enzyme and cell potency, while maintaining selectivity over a number of kinases.
Assuntos
Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Modelos Moleculares , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/química , Pirimidinas/farmacologia , Relação Estrutura-AtividadeRESUMO
B-Raf kinase plays a critical role in the Raf-MEK-ERK signaling pathway and inhibitors of B-Raf could be used in the treatment of melanomas, colorectal cancer, and other Ras related human cancers. We have identified novel small molecule pyrazolo[1,5-a]pyrimidine derivatives as B-Raf kinase inhibitors. Structure-activity relationship was generated for various regions of the scaffold to improve the biochemical profile.
Assuntos
Inibidores de Proteínas Quinases/síntese química , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Pirimidinas/síntese química , Linhagem Celular Tumoral , Simulação por Computador , Humanos , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/metabolismo , Pirimidinas/química , Pirimidinas/farmacologia , Relação Estrutura-AtividadeRESUMO
Our continued effort towards optimization of the pyrazolo[1,5-a]pyrimidine scaffold as B-Raf kinase inhibitors is described. Structure guided design was utilized to introduce kinase hinge region interacting groups in the 2-position of the scaffold. This strategy led to the identification of lead compound 9 with enhanced enzyme and cellular potency, while maintaining good selectivity over a number of kinases.
Assuntos
Antineoplásicos/química , Inibidores Enzimáticos/química , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Pirazóis/química , Pirimidinas/química , Antineoplásicos/farmacologia , Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Humanos , Pirazóis/farmacologia , Pirimidinas/farmacologiaRESUMO
A series of pyrazolo[1,5-alpha]pyrimidine analogs has been prepared and found to be potent and selective B-Raf inhibitors. Molecular modeling suggests they bind to the active conformation of the enzyme.
Assuntos
Descoberta de Drogas , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Pirazóis/farmacologia , Pirimidinas/farmacologia , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas B-raf/metabolismo , Pirazóis/síntese química , Pirazóis/química , Pirimidinas/síntese química , Pirimidinas/química , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
A novel series of pyrazolo[1,5-a]pyrimidines bearing a 3-hydroxyphenyl group at C(3) and substituted tropanes at C(7) have been identified as potent B-Raf inhibitors. Exploration of alternative functional groups as a replacement for the C(3) phenol demonstrated indazole to be an effective isostere. Several compounds possessing substituted indazole residues, such as 4e, 4p, and 4r, potently inhibited cell proliferation at submicromolar concentrations in the A375 and WM266 cell lines, and the latter two compounds also exhibited good therapeutic indices in cells.
Assuntos
Antineoplásicos/química , Inibidores Enzimáticos/química , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Pirazóis/química , Piridinas/química , Pirimidinas/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Humanos , Pirazóis/farmacologia , Piridinas/farmacologia , Pirimidinas/farmacologiaRESUMO
As part of our research effort to discover B-Raf kinase inhibitors, we prepared a series of C-3 substituted N-(3-(pyrazolo[1,5-a]pyrimidin-7-yl)phenyl)-3-(trifluoromethyl)benzamides. X-ray crystallography studies revealed that one of the more potent inhibitors (10n) bound to B-Raf kinase without forming a hinge-binding hydrogen bond. With basic amine residues appended to C-3 aryl residues, cellular activity and solubility were enhanced over previously described compounds of this class.
Assuntos
Benzamidas/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Pirazóis/farmacologia , Pirimidinas/farmacologia , Benzamidas/síntese química , Benzamidas/química , Cristalografia por Raios X , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Proteínas Proto-Oncogênicas B-raf/metabolismo , Pirazóis/síntese química , Pirazóis/química , Pirimidinas/síntese química , Pirimidinas/química , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
A series of substituted 7-alkenyl 4[3-chloro-4-(1-methyl-1H-imidazol-2-ylsulfanyl)]anilino-3-quinolinecarbonitrile analogs were synthesized and evaluated as MEK1 kinase inhibitors. The synthetic details, structure-activity relationships, biological activity, and selected oral exposure studies of these analogs are described. From these studies, compound 5m was chosen as a strong candidate for further evaluation. The selectivity of 5m was ascertained against a panel of 17 kinases, where activity was observed against EGFR, Src, Lyn, and IR kinases. Western blot studies in WM-266 cells demonstrated that 5m inhibited phosphorylation of ERK, while additional kinase pathways tested showed no inhibition at up to 10 microM of 5 m. PK studies, as well as a xenograft and in vivo biomarker studies are described for 5m.
Assuntos
Alcenos/química , Compostos de Anilina/química , MAP Quinase Quinase 1/antagonistas & inibidores , Nitrilas/síntese química , Nitrilas/farmacologia , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacologia , Animais , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Isoquinolinas/química , MAP Quinase Quinase 1/metabolismo , Camundongos , Camundongos Nus , Estrutura Molecular , Neoplasias/enzimologia , Nitrilas/química , Inibidores de Proteínas Quinases/química , Relação Estrutura-Atividade , Especificidade por Substrato , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
A high-throughput screen for Ras-mitogen-activated protein kinase (MAPK) signaling inhibitors identified two series (class 1 and 2) of substituted 4-anilino-3-quinolinecarbonitriles as potent (IC(50)s <10 nmol/L) mitogen-activated protein/extracellular signal-regulated kinase 1 (MEK1) kinase inhibitors. These compounds had cyanoquinoline cores, but differed in their respective aniline groups [1a, 1b: 4-phenoxyphenylaniline; 2a, 2b: 3-chloro-4-(1-methylimidazol-2-sulfanyl)aniline]. These compounds were competitive inhibitors of ATP binding by MEK1 kinase, and they had minimal or no effect on Raf, epidermal growth factor receptor (EGFR), Akt, cyclin-dependent kinase 4 (CDK4), or MK2 kinases at concentrations >100-fold higher than those that inhibited MEK1 kinase. Both class 1 and 2 compounds inhibited in vitro growth of human tumor cell lines. A class 2 compound (2b) was the most potent inhibitor of human tumor cell growth in vitro, and this effect was linked to distinct suppression of MAPK phosphorylation in cells. Compound 2b did not affect phosphorylation status of other kinases, such as EGFR, Akt, and stress-activated protein (SAP)/c-jun-NH kinase (Jnk); nor did it affect overall tyrosine phosphorylation level in cells. However, compound 2b did inhibit MEK1 phosphorylation in cells. Inhibition of MEK1 phosphorylation by 2b was not due to a major effect on Raf kinase activity, because enzyme assays showed minimal Raf kinase inhibition. We believe compound 2b inhibits kinase activity upstream of Raf, and thereby affects MEK1 phosphorylation in cells. Even with the dual effect of 2b on MEK and MAPK phosphorylation, this compound was well tolerated and significantly inhibited growth of the human colon tumor cell line LoVo (at 50 and 100 mg/kg BID, i.p.) in a nude mouse xenograft model.
Assuntos
Compostos de Anilina/farmacologia , Antineoplásicos/farmacologia , Inibidores Enzimáticos/farmacologia , MAP Quinase Quinase 1/antagonistas & inibidores , Trifosfato de Adenosina/metabolismo , Compostos de Anilina/química , Animais , Antineoplásicos/química , Antineoplásicos/classificação , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/classificação , Humanos , Concentração Inibidora 50 , Cinética , MAP Quinase Quinase 1/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Camundongos Nus , Nitrilas/química , Nitrilas/farmacologia , Proteínas Proto-Oncogênicas c-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-raf/metabolismo , Quinolinas/química , Quinolinas/farmacologia , Sensibilidade e Especificidade , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Raf/MEK-1/MAPK cascade inhibitor activity-directed fractionation of the sponge Stylissa massa afforded eight known alkaloids: aldisine (1), 2-bromoaldisine (2), 10Z-debromohymenialdisine (3), 10E-hymenialdisine (4), 10Z-hymenialdisine (5), hymenin (6), oroidin (7), and 4,5-dibromopyrrole-2-carbonamide (8). Both 4 and 5 showed significant enzyme inhibitory activity (IC(50) 3 and 6 nM, respectively). Secondary assays identified these compounds as potent MEK-1 inhibitors. Compounds 4 and 5 also inhibited the growth of human tumor LoVo cells.
Assuntos
Antineoplásicos/farmacologia , Azepinas/farmacologia , Inibidores Enzimáticos/farmacologia , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Poríferos/química , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Pirróis/farmacologia , Animais , Antineoplásicos/isolamento & purificação , Azepinas/isolamento & purificação , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/isolamento & purificação , Ensaio de Imunoadsorção Enzimática , Humanos , MAP Quinase Quinase 1 , Filipinas , Fosforilação , Pirróis/isolamento & purificação , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Clinical trials of selective RAF inhibitors in patients with melanoma tumors harboring activated BRAFV600E have produced very promising results, and a RAF inhibitor has been approved for treatment of advanced melanoma. However, about a third of patients developed resectable skin tumors during the course of trials. This is likely related to observations that RAF inhibitors activate extracellular signal-regulated kinase (ERK) signaling, stimulate proliferation, and induce epithelial hyperplasia in preclinical models. Because these findings raise safety concerns about RAF inhibitor development, we further investigated the underlying mechanisms. We showed that the RAF inhibitor PF-04880594 induces ERK phosphorylation and RAF dimerization in those epithelial tissues that undergo hyperplasia. Hyperplasia and ERK hyperphosphorylation are prevented by treatment with the mitogen-activated protein/extracellular signal-regulated kinase (MEK) inhibitor PD-0325901 at exposures that extrapolate to clinically well-tolerated doses. To facilitate mechanistic and toxicologic studies, we developed a three-dimensional cell culture model of epithelial layering that recapitulated the RAF inhibitor-induced hyperplasia and reversal by MEK inhibitor in vitro. We also showed that PF-04880594 stimulates production of the inflammatory cytokine interleukin 8 in HL-60 cells, suggesting a possible mechanism for the skin flushing observed in dogs. The complete inhibition of hyperplasia by MEK inhibitor in epithelial tissues does not seem to reduce RAF inhibitor efficacy and, in fact, allows doubling of the PF-04880594 dose without toxicity usually associated with such doses. These findings indicated that combination treatment with MEK inhibitors might greatly increase the safety and therapeutic index of RAF inhibitors for the treatment of melanoma and other cancers.
Assuntos
Benzamidas/administração & dosagem , Benzamidas/farmacologia , Difenilamina/análogos & derivados , Epitélio/patologia , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Pirazóis/farmacologia , Pirimidinas/farmacologia , Animais , Benzamidas/química , Difenilamina/administração & dosagem , Difenilamina/química , Difenilamina/farmacologia , Cães , Relação Dose-Resposta a Droga , Epiderme/efeitos dos fármacos , Epiderme/patologia , Epitélio/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Células HL-60 , Humanos , Hiperplasia , Interleucina-8/metabolismo , Camundongos , Camundongos Nus , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Modelos Biológicos , Fosforilação , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/química , Multimerização Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas B-raf/metabolismo , Proteínas Proto-Oncogênicas c-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-raf/metabolismo , Pirazóis/administração & dosagem , Pirazóis/química , Pirimidinas/administração & dosagem , Pirimidinas/químicaRESUMO
Novel indazolylpyrazolo[1,5-a]pyrimidine analogues have been prepared and found to be extremely potent type I B-Raf inhibitors. The lead compound shows good selectivity against a panel of 60 kinases, possesses a desirable pharmacokinetic profile, and demonstrates excellent in vivo antitumor efficacy in B-Raf mutant xenograft models.
Assuntos
Antineoplásicos/síntese química , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Indazóis/síntese química , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Pirazóis/síntese química , Pirimidinas/síntese química , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indazóis/química , Indazóis/farmacologia , Camundongos , Modelos Moleculares , Mutação , Transplante de Neoplasias , Proteínas Proto-Oncogênicas B-raf/genética , Pirazóis/química , Pirazóis/farmacologia , Pirimidinas/química , Pirimidinas/farmacologia , Relação Estrutura-Atividade , Transplante HeterólogoRESUMO
4-[3-Chloro-4-(1-methyl-1H-imidazol-2-ylsulfanyl)]anilino-6,7-diethoxy-3-quinolinecarbonitrile (3) was identified as a MEK1 kinase inhibitor with exceptional activity against LoVo cells. The structure-activity relationships of the C-4 aniline substituents were explored, and water-solubilizing groups were added at the C-7 position to improve physical properties. Secondary cellular assays revealed that a compound possessing the appropriate aniline substituents inhibited MEK1 as well as MAPK phosphorylation, thereby acting as a dual inhibitor of the Ras-MAPK signaling cascade.