RESUMO
PARP-1, the most abundant member of the PARP superfamily of nuclear enzymes, has emerged as a promising molecular target in the past decade particularly for the treatment of cancer. A number of PARP-1 inhibitors, including veliparab discovered at Abbott, have advanced into different stages of clinical trials. Herein we describe the development of a new tetrahydropyridopyridazinone series of PARP-1 inhibitors. Many compounds in this class, such as 20w, displayed excellent potency against the PARP-1 enzyme with a K(i) value of <1nM and an EC(50) value of 1nM in a C41 whole cell assay. The presence of the NH in the tetrahydropyridyl ring of the tetrahydropyridopyridazinone scaffold improved the pharmacokinetic properties over similar carbon based analogs. Compounds 8c and 20u are orally available, and have demonstrated significant efficacy in a B16 murine xenograft model, potentiating the efficacy of temozolomide (TMZ).
Assuntos
Antineoplásicos/farmacologia , Descoberta de Drogas , Inibidores Enzimáticos/farmacologia , Neoplasias Experimentais/tratamento farmacológico , Inibidores de Poli(ADP-Ribose) Polimerases , Piridazinas/farmacologia , Piridinas/farmacologia , Administração Oral , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/síntese química , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/síntese química , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Estrutura Molecular , Neoplasias Experimentais/enzimologia , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/metabolismo , Piridazinas/síntese química , Piridazinas/química , Piridinas/síntese química , Piridinas/química , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
We have developed a series of phenylpyrrolidine- and phenylpiperidine-substituted benzimidazole carboxamide poly(ADP-ribose) polymerase (PARP) inhibitors with excellent PARP enzyme potency as well as single-digit nanomolar cellular potency. These efforts led to the identification of (S)-2-(2-fluoro-4-(pyrrolidin-2-yl)phenyl)-1H-benzimidazole-4-carboxamide (22b, A-966492). Compound 22b displayed excellent potency against the PARP-1 enzyme with a K(i) of 1 nM and an EC(50) of 1 nM in a whole cell assay. In addition, 22b is orally bioavailable across multiple species, crosses the blood-brain barrier, and appears to distribute into tumor tissue. It also demonstrated good in vivo efficacy in a B16F10 subcutaneous murine melanoma model in combination with temozolomide and in an MX-1 breast cancer xenograft model both as a single agent and in combination with carboplatin.
Assuntos
Antineoplásicos/síntese química , Benzimidazóis/síntese química , Inibidores de Poli(ADP-Ribose) Polimerases , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Proteína BRCA1/deficiência , Benzimidazóis/farmacologia , Benzimidazóis/uso terapêutico , Disponibilidade Biológica , Barreira Hematoencefálica/metabolismo , Carboplatina/administração & dosagem , Linhagem Celular Tumoral , Cristalografia por Raios X , Dacarbazina/administração & dosagem , Dacarbazina/análogos & derivados , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Melanoma Experimental/tratamento farmacológico , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Modelos Moleculares , Transplante de Neoplasias , Estereoisomerismo , Relação Estrutura-Atividade , Temozolomida , Transplante HeterólogoRESUMO
Through conformational restriction of a benzamide by formation of a seven-membered hydrogen-bond with an oxindole carbonyl group, a series of PARP inhibitors was designed for appropriate orientation for binding to the PARP surface. This series of compounds with a 3-oxoisoindoline-4-carboxamide core structure, displayed modest to good activity against PARP-1 in both intrinsic and cellular assays. SAR studies at the lactam nitrogen of the pharmacophore have suggested that a secondary or tertiary amine is important for cellular potency. An X-ray structure of compound 1e bound to the protein confirmed the formation of a seven-membered intramolecular hydrogen bond. Though revealed previously in peptides, this type of seven-membered intramolecular hydrogen bond is rarely observed in small molecules. Largely due to the formation of the intramolecular hydrogen bond, the 3-oxoisoindoline-4-carboxamide core structure appears to be planar in the X-ray structure. An additional hydrogen bond interaction of the piperidine nitrogen to Gly-888 also contributes to the binding affinity of 1e to PARP-1.
Assuntos
Amidas/química , Antineoplásicos/química , Descoberta de Drogas/métodos , Isoindóis/química , Neoplasias/enzimologia , Inibidores de Poli(ADP-Ribose) Polimerases , Amidas/metabolismo , Amidas/uso terapêutico , Antineoplásicos/metabolismo , Antineoplásicos/uso terapêutico , Cristalografia por Raios X , Isoindóis/metabolismo , Isoindóis/uso terapêutico , Neoplasias/tratamento farmacológico , Poli(ADP-Ribose) Polimerases/metabolismo , Relação Estrutura-AtividadeRESUMO
We have developed a series of cyclic amine-containing benzimidazole carboxamide PARP inhibitors with a methyl-substituted quaternary center at the point of attachment to the benzimidazole ring system. These compounds exhibit excellent PARP enzyme potency as well as single-digit nanomolar cellular potency. These efforts led to the identification of 3a (2-[(R)-2-methylpyrrolidin-2-yl]-1H-benzimidazole-4-carboxamide, ABT-888), currently in human phase I clinical trials. Compound 3a displayed excellent potency against both the PARP-1 and PARP-2 enzymes with a K(i) of 5 nM and in a C41 whole cell assay with an EC(50) of 2 nM. In addition, 3a is aqueous soluble, orally bioavailable across multiple species, and demonstrated good in vivo efficacy in a B16F10 subcutaneous murine melanoma model in combination with temozolomide (TMZ) and in an MX-1 breast cancer xenograft model in combination with either carboplatin or cyclophosphamide.
Assuntos
Antineoplásicos/farmacologia , Benzimidazóis/farmacologia , Inibidores Enzimáticos/farmacologia , Melanoma Experimental/patologia , Inibidores de Poli(ADP-Ribose) Polimerases , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacocinética , Área Sob a Curva , Benzimidazóis/administração & dosagem , Benzimidazóis/farmacocinética , Disponibilidade Biológica , Carboplatina/administração & dosagem , Ciclofosfamida/administração & dosagem , Dacarbazina/administração & dosagem , Dacarbazina/análogos & derivados , Cães , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/farmacocinética , Feminino , Haplorrinos , Humanos , Espectroscopia de Ressonância Magnética , Camundongos , Camundongos SCID , Ratos , TemozolomidaRESUMO
Poly(ADP-ribose) polymerases (PARPs) play significant roles in various cellular functions including DNA repair and control of RNA transcription. PARP inhibitors have been demonstrated to potentiate the effect of cytotoxic agents or radiation in a number of animal tumor models. Utilizing a benzimidazole carboxamide scaffold in which the amide forms a key intramolecular hydrogen bond for optimal interaction with the enzyme, we have identified a novel series of PARP inhibitors containing a quaternary methylene-amino substituent at the C-2 position of the benzimidazole. Geminal dimethyl analogs at the methylene-amino substituent were typically more potent than mono-methyl derivatives in both intrinsic and cellular assays. Smaller cycloalkanes such as cyclopropyl or cyclobutyl were tolerated at the quaternary carbon while larger rings were detrimental to potency. In vivo efficacy data in a B16F10 murine flank melanoma model in combination with temozolomide (TMZ) are described for two optimized analogs.
Assuntos
Antineoplásicos/síntese química , Química Farmacêutica/instrumentação , Inibidores Enzimáticos/síntese química , Inibidores de Poli(ADP-Ribose) Polimerases , Animais , Antineoplásicos/farmacologia , Benzimidazóis/farmacologia , Linhagem Celular Tumoral , Química Farmacêutica/métodos , DNA/química , Reparo do DNA , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/farmacologia , Cinética , Camundongos , Transplante de Neoplasias , Transcrição GênicaRESUMO
We have developed a series of cyclic amine-containing benzimidazole carboxamide poly(ADP-ribose)polymerase (PARP) inhibitors, with good PARP-1 enzyme potency, as well as cellular potency. These efforts led to the identification of a lead preclinical candidate, 10b, 2-(1-propylpiperidin-4-yl)-1H-benzimidazole-4-carboxamide (A-620223). 10b displayed very good potency against both the PARP-1 enzyme with a K(i) of 8nM and in a whole cell assay with an EC(50) of 3nM. 10b is aqueous soluble, orally bioavailable across multiple species, and demonstrated good in vivo efficacy in a B16F10 subcutaneous murine melanoma model in combination with temozolomide (TMZ) and in an MX-1 breast xenograph model in combination with cisplatin.
Assuntos
Benzimidazóis/química , Benzimidazóis/farmacologia , Neoplasias da Mama/tratamento farmacológico , Melanoma Experimental/tratamento farmacológico , Inibidores de Poli(ADP-Ribose) Polimerases , Animais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Cisplatino/uso terapêutico , Dacarbazina/análogos & derivados , Dacarbazina/uso terapêutico , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Camundongos , Relação Estrutura-Atividade , Temozolomida , Transplante Heterólogo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Compound 7 was identified as a potent (IC50 = 14 nM), selective, and orally bioavailable (F = 70% in mouse) inhibitor of protein kinase B/Akt. While promising efficacy was observed in vivo, this compound showed effects on depolarization of Purkinje fibers in an in vitro assay and CV hypotension in vivo. Guided by an X-ray structure of 7 bound to protein kinase A, which has 80% homology with Akt in the kinase domain, our efforts have focused on structure-activity relationship (SAR) studies of the phenyl moiety, in an attempt to address the cardiovascular liability and further improve the Akt potency. A novel and efficient synthetic route toward diversely substituted phenyl derivatives of 7 was developed utilizing a copper-mediated aziridine ring-opening reaction as the key step. To improve the selectivity of these Akt inhibitors over other protein kinases, a nitrogen atom was incorporated into selected phenyl analogues of 7 at the C-6 position of the methyl indazole scaffold. These modifications resulted in the discovery of inhibitor 37c with greater potency (IC50 = 0.6 nM vs Akt), selectivity, and improved cardiovascular safety profile. The SARs, pharmacokinetic profile, and CV safety of selected Akt inhibitors will be discussed.
Assuntos
Hipotensão/induzido quimicamente , Indazóis/síntese química , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Pirazóis/síntese química , Piridinas/síntese química , Administração Oral , Animais , Disponibilidade Biológica , Cristalografia por Raios X , Cães , Indazóis/efeitos adversos , Indazóis/farmacologia , Camundongos , Modelos Moleculares , Conformação Proteica , Ramos Subendocárdicos/efeitos dos fármacos , Ramos Subendocárdicos/fisiologia , Pirazóis/efeitos adversos , Pirazóis/farmacologia , Piridinas/efeitos adversos , Piridinas/farmacologia , Ratos , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Thr-211 is one of three different amino acid residues in the kinase domain of protein kinase B/Akt as compared to protein kinase A (PKA), a closely related analog in the same AGC family. In an attempt to improve the potency and selectivity of our indazole-pyridine series of Akt inhibitors over PKA, efforts have focused on the incorporation of a chemical functionality to interact with the hydroxy group of Thr-211. Several substituents including an oxygen anion, amino, and nitro groups have been introduced at the C-6 position of the indazole scaffold, leading to a significant drop in Akt potency. Incorporation of a nitrogen atom into the phenyl ring at the same position (i.e., 9f) maintained the Akt activity and, in some cases, improved the selectivity over PKA. The structure-activity relationships of the new pyridine-pyrazolopyridine series of Akt inhibitors and their structural features when bound to PKA are also discussed.
Assuntos
Inibidores Enzimáticos/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Pirazóis/síntese química , Piridinas/síntese química , Cristalografia por Raios X , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/patologia , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Pirazóis/química , Pirazóis/farmacologia , Piridinas/química , Piridinas/farmacologia , Relação Estrutura-Atividade , Células Tumorais Cultivadas/efeitos dos fármacosRESUMO
The structure-activity relationships of a series of isoquinoline-pyridine-based protein kinase B/Akt antagonists have been investigated in an effort to improve the major short-comings of the lead compound 3, including poor pharmacokinetic profiles in several species (e.g., mouse i.v. t(1/2) = 0.3 h, p.o. F = 0%). Chlorination at C-1 position of the isoquinoline improved its pharmacokinetic property in mice (i.v. t(1/2) = 5.0 h, p.o. F = 51%) but resulted in >500-fold drop in potency. In a mouse MiaPaCa-2 xenograft model, an amino analog 10y significantly slowed the tumor growth, however was accompanied by toxicity.
Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Isoquinolinas/química , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Piridinas/química , Piridinas/farmacologia , Animais , Antineoplásicos/química , Linhagem Celular Tumoral , Cristalografia por Raios X , Humanos , Camundongos , Estrutura Molecular , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Piridinas/síntese química , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
We describe a series of potent and selective oxindole-pyridine-based protein kinase B/Akt inhibitors. The most potent compound 11n in this series demonstrated an IC(50) of 0.17nM against Akt1 and more than 100-fold selectivity over other Akt isozymes. The selectivity against other protein kinases was highly dependent on the C-3 substitutions at the oxindole scaffold, with unsubstituted 9e or 3-furan-2-ylmethylene (11n) more selective and 3-(1H-pyrrol-2-yl)methylene (11f) or 3-(1H-imidazol-2-yl)methylene (11k) less selective. In a mouse xenograft model, 9d, 11f, and 11n inhibited tumor growth but with accompanying toxicity.