RESUMO
Ponatinib (AP24534) was previously identified as a pan-BCR-ABL inhibitor that potently inhibits the T315I gatekeeper mutant, and has advanced into clinical development for the treatment of refractory or resistant CML. In this study, we explored a novel series of five and six membered monocycles as alternate hinge-binding templates to replace the 6,5-fused imidazopyridazine core of ponatinib. Like ponatinib, these monocycles are tethered to pendant toluanilides via an ethynyl linker. Several compounds in this series displayed excellent in vitro potency against both native BCR-ABL and the T315I mutant. Notably, a subset of inhibitors exhibited desirable PK and were orally active in a mouse model of T315I-driven CML.
Assuntos
Alcinos/síntese química , Alcinos/farmacologia , Compostos de Anilina/síntese química , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Tolueno/síntese química , Administração Oral , Alcinos/química , Compostos de Anilina/química , Compostos de Anilina/farmacologia , Animais , Ciclização , Modelos Animais de Doenças , Proteínas de Fusão bcr-abl/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Camundongos , Modelos Moleculares , Estrutura Molecular , Mutação , Ratos , Relação Estrutura-Atividade , Tolueno/química , Tolueno/farmacologiaRESUMO
Novel N(9)-arenethenyl purines, optimized potent dual Src/Abl tyrosine kinase inhibitors, are described. The key structural feature is a trans vinyl linkage at N(9) on the purine core which projects hydrophobic substituents into the selectivity pocket at the rear of the ATP site. Their synthesis was achieved through a Horner-Wadsworth-Emmons reaction of N(9)-phosphorylmethylpurines and substituted benzaldehydes or Heck reactions between 9-vinyl purines and aryl halides. Most compounds are potent inhibitors of both Src and Abl kinase, and several possess good oral bioavailability.
Assuntos
Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Purinas/química , Purinas/farmacologia , Quinases da Família src/antagonistas & inibidores , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Inibidores do Crescimento/química , Inibidores do Crescimento/farmacologia , Humanos , Células K562 , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-abl/fisiologia , RatosRESUMO
In the treatment of chronic myeloid leukemia (CML) with BCR-ABL kinase inhibitors, the T315I gatekeeper mutant has emerged as resistant to all currently approved agents. This report describes the structure-guided design of a novel series of potent pan-inhibitors of BCR-ABL, including the T315I mutation. A key structural feature is the carbon-carbon triple bond linker which skirts the increased bulk of Ile315 side chain. Extensive SAR studies led to the discovery of development candidate 20g (AP24534), which inhibited the kinase activity of both native BCR-ABL and the T315I mutant with low nM IC(50)s, and potently inhibited proliferation of corresponding Ba/F3-derived cell lines. Daily oral administration of 20g significantly prolonged survival of mice injected intravenously with BCR-ABL(T315I) expressing Ba/F3 cells. These data, coupled with a favorable ADME profile, support the potential of 20g to be an effective treatment for CML, including patients refractory to all currently approved therapies.
Assuntos
Antineoplásicos/síntese química , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Imidazóis/síntese química , Inibidores de Proteínas Quinases/síntese química , Piridazinas/síntese química , Administração Oral , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Barreira Hematoencefálica/metabolismo , Linhagem Celular Tumoral , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Proteínas de Fusão bcr-abl/genética , Imidazóis/farmacocinética , Imidazóis/farmacologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/mortalidade , Camundongos , Camundongos SCID , Modelos Moleculares , Mutação , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/farmacologia , Piridazinas/farmacocinética , Piridazinas/farmacologia , RatosRESUMO
Inhibition of BCR-ABL by imatinib induces durable responses in many patients with chronic myeloid leukemia (CML), but resistance attributable to kinase domain mutations can lead to relapse and a switch to second-line therapy with nilotinib or dasatinib. Despite three approved therapeutic options, the cross-resistant BCR-ABL(T315I) mutation and compound mutants selected on sequential inhibitor therapy remain major clinical challenges. We report design and preclinical evaluation of AP24534, a potent, orally available multitargeted kinase inhibitor active against T315I and other BCR-ABL mutants. AP24534 inhibited all tested BCR-ABL mutants in cellular and biochemical assays, suppressed BCR-ABL(T315I)-driven tumor growth in mice, and completely abrogated resistance in cell-based mutagenesis screens. Our work supports clinical evaluation of AP24534 as a pan-BCR-ABL inhibitor for treatment of CML.
Assuntos
Proteínas de Fusão bcr-abl/antagonistas & inibidores , Imidazóis/farmacologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Piridazinas/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Cristalografia por Raios X , Proteínas de Fusão bcr-abl/química , Proteínas de Fusão bcr-abl/genética , Proteínas de Fusão bcr-abl/metabolismo , Humanos , Imidazóis/química , Leucemia Mielogênica Crônica BCR-ABL Positiva/enzimologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Camundongos , Camundongos SCID , Modelos Moleculares , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-abl/química , Proteínas Proto-Oncogênicas c-abl/genética , Proteínas Proto-Oncogênicas c-abl/metabolismo , Piridazinas/química , Transdução de Sinais/efeitos dos fármacosRESUMO
A novel series of potent dual Src/Abl kinase inhibitors based on a 9-(arenethenyl)purine core has been identified. Unlike traditional dual Src/Abl inhibitors targeting the active enzyme conformation, these inhibitors bind to the inactive, DFG-out conformation of both kinases. Extensive SAR studies led to the discovery of potent and orally bioavailable inhibitors, some of which demonstrated in vivo efficacy. Once-daily oral administration of inhibitor 9i (AP24226) significantly prolonged the survival of mice injected intravenously with wild type Bcr-Abl expressing Ba/F3 cells at a dose of 10 mg/kg. In a separate model, oral administration of 9i to mice bearing subcutaneous xenografts of Src Y527F expressing NIH 3T3 cells elicited dose-dependent tumor shrinkage with complete tumor regression observed at the highest dose. Notably, several inhibitors (e.g., 14a, AP24163) exhibited modest cellular potency (IC50 = 300-400 nM) against the Bcr-Abl mutant T315I, a variant resistant to all currently marketed therapies for chronic myeloid leukemia.
Assuntos
Desenho de Fármacos , Inibidores de Proteínas Quinases/síntese química , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Purinas/síntese química , Quinases da Família src/antagonistas & inibidores , Animais , Feminino , Humanos , Células K562 , Camundongos , Células NIH 3T3 , Conformação Proteica , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-abl/química , Purinas/farmacologia , Ratos , Relação Estrutura-Atividade , Quinases da Família src/químicaRESUMO
Oncogenic mutations of the Kit receptor tyrosine kinase occur in several types of malignancy. Juxtamembrane domain mutations are common in gastrointestinal stromal tumors, whereas mutations in the kinase activation loop, most commonly D816V, are seen in systemic mastocytosis and acute myelogenous leukemia. Kit activation-loop mutants are insensitive to imatinib mesylate and have been largely resistant to targeted inhibition. We determined the sensitivities of both Kit mutant classes to the adenosine triphosphate (ATP)-based inhibitors AP23464 and AP23848. In cell lines expressing activation-loop mutants, low-nM concentrations of AP23464 inhibited phosphorylation of Kit and its downstream targets Akt and signal transducer and activator of transcription 3 (STAT3). This was associated with cell-cycle arrest and apoptosis. Wild-type Kit-and juxtamembrane-mutant-expressing cell lines required considerably higher concentrations for equivalent inhibition, suggesting a therapeutic window in which cells harboring D816V Kit could be eliminated without interfering with normal cellular function. Additionally, AP23464 did not disrupt normal hematopoietic progenitor-cell growth at concentrations that inhibited activation-loop mutants of Kit. In a murine model, AP23848 inhibited activation-loop mutant Kit phosphorylation and tumor growth. Thus, AP23464 and AP23848 potently and selectively target activation-loop mutants of Kit in vitro and in vivo and could have therapeutic potential against D816V-expressing malignancies.