RESUMO
High levels of Pim expression have been implicated in several hematopoietic and solid tumor cancers, suggesting that inhibition of Pim signaling could provide patients with therapeutic benefit. Herein, we describe our progress towards this goal using a screening hit (rac-1) as a starting point. Modification of the indazole ring resulted in the discovery of a series of imidazopyridazine-based Pim inhibitors exemplified by compound 22m, which was found to be a subnanomolar inhibitor of the Pim-1 and Pim-2 isoforms (IC50 values of 0.024nM and 0.095nM, respectively) and to potently inhibit the phosphorylation of BAD in a cell line that expresses high levels of all Pim isoforms, KMS-12-BM (IC50=28nM). Profiling of Pim-1 and Pim-2 expression levels in a panel of multiple myeloma cell lines and correlation of these data with the potency of compound 22m in a proliferation assay suggests that Pim-2 inhibition would be advantageous for this indication.
Assuntos
Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Piridazinas/química , Piridazinas/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Modelos Moleculares , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-pim-1/metabolismo , Relação Estrutura-AtividadeRESUMO
PIM kinases are a family of Ser/Thr kinases that are implicated in tumorigenesis. The discovery of a new class of PIM inhibitors, 5-(1H-indol-5-yl)-1,3,4-thiadiazol-2-amines, is discussed with optimized compounds showing excellent potency against all three PIM isoforms.
Assuntos
Aminas/química , Aminas/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Aminas/síntese química , Carbolinas/síntese química , Carbolinas/química , Carbolinas/farmacologia , Linhagem Celular Tumoral , Descoberta de Drogas , Humanos , Modelos Moleculares , Inibidores de Proteínas Quinases/síntese química , Proteínas Proto-Oncogênicas c-pim-1/química , Relação Estrutura-AtividadeRESUMO
The three Pim kinases are a small family of serine/threonine kinases regulating several signaling pathways that are fundamental to tumorigenesis. As such, the Pim kinases are a very attractive target for pharmacological inhibition in cancer therapy. Herein, we describe our efforts toward the development of a potent, pan-Pim inhibitor. The synthesis and hit-to-lead SAR development from a 3-(pyrazin-2-yl)-1H-indazole derived hit 2 to the identification of a series of potent, pan-Pim inhibitors such as 13o are described.
Assuntos
Indazóis/química , Indazóis/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Descoberta de Drogas , Humanos , Relação Estrutura-AtividadeRESUMO
High levels of Pim expression have been implicated in several hematopoietic and solid tumor cancers. These findings suggest that inhibition of Pim signaling by a small molecule Pim-1,2 inhibitor could provide patients with therapeutic benefit. Herein, we describe our progress towards this goal starting from the highly Pim-selective indole-thiadiazole compound (1), which was derived from a nonselective hit identified in a high throughput screening campaign. Optimization of this compound's potency and its pharmacokinetic properties resulted in the discovery of compound 29. Cyclopropane 29 was found to exhibit excellent enzymatic potency on the Pim-1 and Pim-2 isoforms (Ki values of 0.55nM and 0.28nM, respectively), and found to inhibit the phosphorylation of BAD in the Pim-overexpressing KMS-12 cell line (IC50=150nM). This compound had moderate clearance and bioavailability in rat (CL=2.42L/kg/h; %F=24) and exhibited a dose-dependent inhibition of p-BAD in KMS-12 tumor pharmacodynamic (PD) model with an EC50 value of 6.74µM (18µg/mL) when dosed at 10, 30, 100 and 200mg/kg po in mice.
Assuntos
Oxidiazóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Cristalografia por Raios X , Descoberta de Drogas , Estrutura Molecular , Oxidiazóis/químicaRESUMO
Replacement of the piperazine sulfonamide portion of the PI3Kα inhibitor AMG 511 (1) with a range of aliphatic alcohols led to the identification of a truncated gem-dimethylbenzylic alcohol analog, 2-(5-(4-amino-6-methyl-1,3,5-triazin-2-yl)-6-((5-fluoro-6-methoxypyridin-3-yl)amino)pyridin-3-yl)propan-2-ol (7). This compound possessed good in vitro efficacy and pharmacokinetic parameters and demonstrated an EC50 of 239 ng/mL in a mouse liver pharmacodynamic model measuring the inhibition of hepatocyte growth factor (HGF)-induced Akt Ser473 phosphorylation in CD1 nude mice 6 h post-oral dosing.
Assuntos
Álcoois/química , Inibidores de Fosfoinositídeo-3 Quinase , Piperazinas/química , Inibidores de Proteínas Quinases/química , Piridinas/síntese química , Sulfonamidas/química , Triazinas/síntese química , Animais , Feminino , Meia-Vida , Fígado/metabolismo , Masculino , Camundongos , Camundongos Nus , Conformação Molecular , Fosfatidilinositol 3-Quinases/metabolismo , Piperazina , Piperazinas/metabolismo , Piperazinas/farmacocinética , Ligação Proteica , Inibidores de Proteínas Quinases/metabolismo , Inibidores de Proteínas Quinases/farmacocinética , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Piridinas/metabolismo , Piridinas/farmacocinética , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-Atividade , Sulfonamidas/metabolismo , Sulfonamidas/farmacocinética , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismo , Triazinas/metabolismo , Triazinas/farmacocinéticaRESUMO
Structure-activity relationship (SAR) investigations of a novel class of triazolopyridazinone p38α mitogen activated protein kinase (MAPK) inhibitors are disclosed. From these studies, increased in vitro potency was observed for 2,6-disubstituted phenyl moieties and N-ethyl triazolopyridazinone cores due to key contacts with Leu108, Ala157 and Val38. Further investigation led to the identification of three compounds, 3g, 3j and 3m that are highly potent inhibitors of LPS-induced MAPKAP kinase 2 (MK2) phosphorylation in 50% human whole blood (hWB), and possess desirable in vivo pharmacokinetic and kinase selectivity profiles.
Assuntos
Proteína Quinase 14 Ativada por Mitógeno/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Piridazinas/farmacologia , Triazóis/farmacologia , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Humanos , Proteína Quinase 14 Ativada por Mitógeno/metabolismo , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Piridazinas/síntese química , Piridazinas/química , Estereoisomerismo , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/químicaRESUMO
Replacement of the azetidine carboxylate of an S1P(1) agonist development candidate, AMG 369, with a range of acyclic head-groups led to the identification of a novel, S1P(3)-sparing S1P(1) agonist, (-)-2-amino-4-(3-fluoro-4-(5-(1-phenylcyclopropyl)thiazolo[5,4-b]pyridin-2-yl)phenyl)-2-methylbutanoic acid (8c), which possessed good in vivo efficacy and pharmacokinetic properties. A 0.3mg/kg oral dose of 8c produced a statistically significant reduction in blood lymphocyte counts 24h post-dosing in female Lewis rats.
Assuntos
Aminas/química , Ácidos Carboxílicos/química , Isoformas de Proteínas/química , Piridinas/química , Piridinas/síntese química , Piridinas/farmacologia , Receptores de Lisoesfingolipídeo/agonistas , Tiazóis/química , Administração Oral , Animais , Ciclização , Feminino , Concentração Inibidora 50 , Estrutura Molecular , Ligação Proteica/efeitos dos fármacos , Ratos , Ratos Endogâmicos Lew , Tiazóis/síntese química , Tiazóis/farmacologiaRESUMO
We reveal how a N-scan SAR strategy (systematic substitution of each CH group with a N atom) was employed for quinolinone-based S1P(1) agonist 5 to modulate physicochemical properties and optimize in vitro and in vivo activity. The diaza-analog 17 displays improved potency (hS1P(1) RI; 17: EC(50)=0.020 µM, 120% efficacy; 5: EC(50)=0.070 µM, 110% efficacy) and selectivity (hS1P(3) Ca(2+) flux; 17: EC(50) >25 µM; 5: EC(50)=1.5 µM, 92% efficacy), as well as enhanced pharmacokinetics (17: CL=0.15 L/h/kg, V(dss)=5.1L/kg, T(1/2)=24h, %F=110; 5: CL=0.93L/h/kg, V(dss)=11L/kg, T(1/2)=15 h, %F=60) and pharmacodynamics (17: 1.0mg/kg po, 24h PLC POC=-67%; 5: 3mg/kg po, 24h PLC POC=-51%) in rat.
Assuntos
Físico-Química/métodos , Quinolonas/farmacologia , Receptores de Lisoesfingolipídeo/agonistas , Receptores de Lisoesfingolipídeo/química , Animais , Área Sob a Curva , Doenças Cardiovasculares/metabolismo , Desenho de Fármacos , Feminino , Humanos , Imunossupressores/farmacologia , Técnicas In Vitro , Cinética , Linfócitos/citologia , Linfócitos/metabolismo , Modelos Químicos , Esclerose Múltipla/tratamento farmacológico , Quinolonas/química , Ratos , Ratos Endogâmicos Lew , Relação Estrutura-AtividadeRESUMO
A novel class of pyrazolopyridazine p38alpha mitogen-activated protein kinase (MAPK) inhibitors is disclosed. A structure activity relationship (SAR) investigation was conducted driven by the ability of these compounds to inhibit the p38alpha enzyme, the secretion of TNFalpha in a LPS-challenged THP1 cell line and TNFalpha-induced production of IL-8 in the presence of 50% human whole blood (hWB). This study resulted in the discovery of several inhibitors with IC(50) values in the single-digit nanomolar range in hWB. Further investigation of the pharmacokinetic profiles of these lead compounds led to the identification of three potent and orally bioavailable p38alpha inhibitors 2h, 2m, and 13h. Inhibitor 2m was found to be highly selective for p38alpha/beta over a panel of 402 other kinases in Ambit screening, and was highly efficacious in vivo in the inhibition of TNFalpha production in LPS-stimulated Lewis rats with an ED(50) of ca. 0.08mg/kg.
Assuntos
Anti-Inflamatórios/química , Benzamidas/química , Inibidores de Proteínas Quinases/química , Pirazóis/química , Piridazinas/química , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Administração Oral , Animais , Anti-Inflamatórios/síntese química , Anti-Inflamatórios/farmacocinética , Benzamidas/síntese química , Benzamidas/farmacocinética , Sítios de Ligação , Linhagem Celular Tumoral , Cristalografia por Raios X , Humanos , Interleucina-8 , Lipopolissacarídeos/toxicidade , Masculino , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Pirazóis/síntese química , Pirazóis/farmacocinética , Piridazinas/síntese química , Piridazinas/farmacocinética , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
A series of 2-aminothiadiazole of inhibitors of AKT1 is described. SAR relationships are discussed, along with selectivity for protein kinase A (PKA) and cyclin-dependent kinase 2 (CDK2). Moderate selectivity observed in several compounds for AKT1 versus PKA is rationalized by X-ray crystallographic analysis. Key compounds showed activity in cellular assays measuring phosphorylation of two AKT substrates, PRAS40 and FKHRL1. Compound 30 was advanced to a mouse liver PD assay, where it showed dose-dependent inhibition of AKT activity, as measured by the inhibition of phospho-PRAS40.
Assuntos
Antineoplásicos/química , Isoquinolinas/química , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Tiadiazóis/química , Tiazóis/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/farmacocinética , Domínio Catalítico , Cristalografia por Raios X , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Quinase 2 Dependente de Ciclina/antagonistas & inibidores , Quinase 2 Dependente de Ciclina/metabolismo , Isoquinolinas/síntese química , Isoquinolinas/farmacocinética , Camundongos , Neoplasias/tratamento farmacológico , Fosforilação , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Relação Estrutura-Atividade , Tiadiazóis/síntese química , Tiadiazóis/farmacocinética , Tiazóis/síntese química , Tiazóis/farmacocinéticaRESUMO
A novel class of fused pyrazole-derived inhibitors of p38alpha mitogen-activated protein kinase (MAPK) is disclosed. These inhibitors were evaluated for their ability to inhibit the p38alpha enzyme, the secretion of TNFalpha in a LPS-challenged THP1 cell line and TNFalpha-induced production of IL-8 in 50% human whole blood. This series was optimized through a SAR investigation to provide inhibitors with IC(50) values in the low single-digit nanomolar range in whole blood. Further investigation of their pharmacokinetic profiles led to the identification of two potent and orally bioavailable p38 inhibitors 10 m and 10 q. Inhibitor 10 m was found to be efficacious in vivo in the inhibition of TNFalpha production in LPS-stimulated Lewis rats with an ED(50) of 0.1mg/kg while 10 q was found to have an ED(50) of 0.05-0.07 mg/kg.
Assuntos
Anti-Inflamatórios/química , Proteína Quinase 14 Ativada por Mitógeno/antagonistas & inibidores , Inibidores de Proteínas Quinases/química , Pirazóis/química , Piridonas/química , Administração Oral , Animais , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/farmacocinética , Sítios de Ligação , Linhagem Celular , Simulação por Computador , Cristalografia por Raios X , Humanos , Interleucina-8/sangue , Lipopolissacarídeos/farmacologia , Masculino , Proteína Quinase 14 Ativada por Mitógeno/metabolismo , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/farmacocinética , Pirazóis/administração & dosagem , Pirazóis/farmacocinética , Piridonas/administração & dosagem , Piridonas/farmacocinética , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Pim kinases are a family of constitutively active serine/threonine kinases that are partially redundant and regulate multiple pathways important for cell growth and survival. In human disease, high expression of the three Pim isoforms has been implicated in the progression of hematopoietic and solid tumor cancers, which suggests that Pim kinase inhibitors could provide patients with therapeutic benefit. Herein, we describe the structure-guided optimization of a series of quinazolinone-pyrrolodihydropyrrolone analogs leading to the identification of potent pan-Pim inhibitor 28 with improved potency, solubility, and drug-like properties. Compound 28 demonstrated on-target Pim activity in an in vivo pharmacodynamic assay with significant inhibition of BAD phosphorylation in KMS-12-BM multiple myeloma tumors for 16 h postdose. In a 2-week mouse xenograft model, daily dosing of compound 28 resulted in 33% tumor regression at 100 mg/kg.
Assuntos
Antineoplásicos/uso terapêutico , Neoplasias Hematológicas/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Pirróis/uso terapêutico , Quinazolinonas/uso terapêutico , Animais , Antineoplásicos/síntese química , Antineoplásicos/farmacocinética , Feminino , Humanos , Camundongos SCID , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Pirróis/síntese química , Pirróis/farmacocinética , Quinazolinonas/síntese química , Quinazolinonas/farmacocinética , Relação Estrutura-Atividade , Suínos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Deregulation of the receptor tyrosine kinase c-Kit is associated with an increasing number of human diseases, including certain cancers and mast cell diseases. Interference of c-Kit signaling with multi-kinase inhibitors has been shown clinically to successfully treat gastrointestinal stromal tumors and mastocytosis. Targeted therapy of c-Kit activity may provide therapeutic advantages against off-target effects for non-oncology applications. A new structural class of c-Kit inhibitors is described, including in vitro c-Kit potency, kinase selectivity, and the observed binding mode.
Assuntos
Amidas/síntese química , Amidas/farmacologia , Isoxazóis/síntese química , Isoxazóis/farmacologia , Proteínas Proto-Oncogênicas c-kit/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-kit/metabolismo , Amidas/química , Técnicas de Química Combinatória , Cristalografia por Raios X , Humanos , Isoxazóis/química , Conformação Molecular , Estrutura Molecular , Receptores Proteína Tirosina Quinases/metabolismo , Relação Estrutura-Atividade , Proteínas Quinases p38 Ativadas por Mitógeno/efeitos dos fármacosRESUMO
Cathepsin K is a cysteine protease that plays an important role in the pathological process of bone resorption. Selective cathepsin K inhibitors may thus provide great potential in the treatment of osteoporosis. Pharmaceutical interest in this area is highlighted by the rising number of publications and patent applications. Most recently, the interim results of three clinical trials conducted by Novartis, GlaxoSmithKline, and Merck have strengthened the validation of the target for the therapeutic intervention of osteoporosis. Here we report a series of Cbz-leucyl-(4-piperidinylphenyl)aminoethyl amides based on dipeptidyl anilines for cathepsin K inhibition. These new non-covalent inhibitors exhibit single digit nM inhibition of the cathepsin family. Molecular modeling studies on the interactions responsible for the potency of these inhibitors for cathepsin K will be also discussed.
Assuntos
Catepsinas/antagonistas & inibidores , Inibidores de Cisteína Proteinase/uso terapêutico , Osteoporose/tratamento farmacológico , Catepsina K , Inibidores de Cisteína Proteinase/química , Inibidores de Cisteína Proteinase/farmacologia , Humanos , Modelos Moleculares , Relação Estrutura-AtividadeRESUMO
Panitumumab and cetuximab target the epidermal growth factor receptor for the treatment of metastatic colorectal cancer. These therapies provide a significant survival benefit to patients with metastatic colorectal cancer with wild-type RAS. A single point mutation in the ectodomain of EGFR (S468R) confers acquired or secondary resistance in cetuximab treated patients, which is not observed in panitumumab-treated patients. Structural and biophysical studies presented here show this mutation directly blocks cetuximab binding to EGFR domain III and describes a unique mechanism by which panitumumab uses a central cavity to accommodate this mutation.
RESUMO
The identification of Pim-1/2 kinase overexpression in B-cell malignancies suggests that Pim kinase inhibitors will have utility in the treatment of lymphoma, leukemia, and multiple myeloma. Starting from a moderately potent quinoxaline-dihydropyrrolopiperidinone lead, we recognized the potential for macrocyclization and developed a series of 13-membered macrocycles. The structure-activity relationships of the macrocyclic linker were systematically explored, leading to the identification of 9c as a potent, subnanomolar inhibitor of Pim-1 and -2. This molecule also potently inhibited Pim kinase activity in KMS-12-BM, a multiple myeloma cell line with relatively high endogenous levels of Pim-1/2, both in vitro (pBAD IC50 = 25 nM) and in vivo (pBAD EC50 = 30 nM, unbound), and a 100 mg/kg daily dose was found to completely arrest the growth of KMS-12-BM xenografts in mice.
RESUMO
The high expression of proviral insertion site of Moloney murine leukemia virus kinases (Pim-1, -2, and -3) in cancers, particularly the hematopoietic malignancies, is believed to play a role in promoting cell survival and proliferation while suppressing apoptosis. The three isoforms of Pim protein appear largely redundant in their oncogenic functions. Thus, a pan-Pim kinase inhibitor is highly desirable. However, cell active pan-Pim inhibitors have proven difficult to develop because Pim-2 has a low Km for ATP and therefore requires a very potent inhibitor to effectively block the kinase activity at cellular ATP concentrations. Herein, we report a series of quinazolinone-pyrrolopyrrolones as potent and selective pan-Pim inhibitors. In particular, compound 17 is orally efficacious in a mouse xenograft model (KMS-12 BM) of multiple myeloma, with 93% tumor growth inhibition at 50 mg/kg QD upon oral dosing.
Assuntos
Antineoplásicos/farmacologia , Descoberta de Drogas , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Pirróis/farmacologia , Quinazolinonas/farmacologia , Administração Oral , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Camundongos , Modelos Moleculares , Estrutura Molecular , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/patologia , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-pim-1/metabolismo , Pirróis/administração & dosagem , Pirróis/química , Quinazolinonas/administração & dosagem , Quinazolinonas/química , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Success in the design of targeted covalent inhibitors depends in part on a knowledge of the factors influencing electrophile reactivity. In an effort to further develop an understanding of structure-reactivity relationships among N-arylacrylamides, we determined glutathione (GSH) reaction rates for a family of N-arylacrylamides independently substituted at ortho-, meta-, and para-positions with 11 different groups common to inhibitor design. We find that substituent effects on reaction rates show a linear Hammett correlation for ortho-, meta-, and para-substitution. In addition, we note a correlation between (1)H and (13)C NMR chemical shifts of the acrylamide with GSH reaction rates, suggesting that NMR chemical shifts may be a convenient surrogate measure of relative acrylamide reactivity. Density functional theory calculations reveal a correlation between computed activation parameters and experimentally determined reaction rates, validating the use of such methodology for the screening of synthetic candidates in a prospective fashion.
Assuntos
Acrilamidas/química , Acrilamidas/farmacologia , Glutationa/metabolismo , Descoberta de Drogas , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , TermodinâmicaRESUMO
The kinase/endonuclease inositol requiring enzyme 1 (IRE1α), one of the sensors of unfolded protein accumulation in the endoplasmic reticulum that triggers the unfolded protein response (UPR), has been investigated as an anticancer target. We identified potent allosteric inhibitors of IRE1α endonuclease activity that bound to the kinase site on the enzyme. Structure-activity relationship (SAR) studies led to 16 and 18, which were selective in kinase screens and were potent against recombinant IRE1α endonuclease as well as cellular IRE1α. The first X-ray crystal structure of a kinase inhibitor (16) bound to hIRE1α was obtained. Screening of native tumor cell lines (>300) against selective IRE1α inhibitors failed to demonstrate any effect on cellular viability. These results suggest that IRE1α activity is not essential for viability in most tumor cell lines, in vitro, and that interfering with the survival functions of the UPR may not be an effective strategy to block tumorigenesis.
RESUMO
The development and optimization of a series of quinolinylpurines as potent and selective PI3Kδ kinase inhibitors with excellent physicochemical properties are described. This medicinal chemistry effort led to the identification of 1 (AMG319), a compound with an IC50 of 16 nM in a human whole blood assay (HWB), excellent selectivity over a large panel of protein kinases, and a high level of in vivo efficacy as measured by two rodent disease models of inflammation.