RESUMEN

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).

Asunto(s)

Antineoplásicos/farmacología , Descubrimiento de Drogas , Inhibidores Enzimáticos/farmacología , Neoplasias Experimentales/tratamiento farmacológico , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Piridazinas/farmacología , Piridinas/farmacología , Administración Oral , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/síntesis química , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/síntesis química , Femenino , Ratones , Ratones Endogámicos C57BL , Modelos Moleculares , Estructura Molecular , Neoplasias Experimentales/enzimología , Poli(ADP-Ribosa) Polimerasa-1 , Poli(ADP-Ribosa) Polimerasas/metabolismo , Piridazinas/síntesis química , Piridazinas/química , Piridinas/síntesis química , Piridinas/química , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

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.

Asunto(s)

Antineoplásicos/síntesis química , Bencimidazoles/síntesis química , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Animales , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Proteína BRCA1/deficiencia , Bencimidazoles/farmacología , Bencimidazoles/uso terapéutico , Disponibilidad Biológica , Barrera Hematoencefálica/metabolismo , Carboplatino/administración & dosificación , Línea Celular Tumoral , Cristalografía por Rayos X , Dacarbazina/administración & dosificación , Dacarbazina/análogos & derivados , Ensayos de Selección de Medicamentos Antitumorales , Femenino , Melanoma Experimental/tratamiento farmacológico , Ratones , Ratones Endogámicos C57BL , Ratones SCID , Modelos Moleculares , Trasplante de Neoplasias , Estereoisomerismo , Relación Estructura-Actividad , Temozolomida , Trasplante Heterólogo

RESUMEN

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.

Asunto(s)

Amidas/química , Antineoplásicos/química , Descubrimiento de Drogas/métodos , Isoindoles/química , Neoplasias/enzimología , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Amidas/metabolismo , Amidas/uso terapéutico , Antineoplásicos/metabolismo , Antineoplásicos/uso terapéutico , Cristalografía por Rayos X , Isoindoles/metabolismo , Isoindoles/uso terapéutico , Neoplasias/tratamiento farmacológico , Poli(ADP-Ribosa) Polimerasas/metabolismo , Relación Estructura-Actividad

RESUMEN

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.

Asunto(s)

Antineoplásicos/farmacología , Bencimidazoles/farmacología , Inhibidores Enzimáticos/farmacología , Melanoma Experimental/patología , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacocinética , Área Bajo la Curva , Bencimidazoles/administración & dosificación , Bencimidazoles/farmacocinética , Disponibilidad Biológica , Carboplatino/administración & dosificación , Ciclofosfamida/administración & dosificación , Dacarbazina/administración & dosificación , Dacarbazina/análogos & derivados , Perros , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/farmacocinética , Femenino , Haplorrinos , Humanos , Espectroscopía de Resonancia Magnética , Ratones , Ratones SCID , Ratas , Temozolomida

RESUMEN

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.

Asunto(s)

Antineoplásicos/síntesis química , Química Farmacéutica/instrumentación , Inhibidores Enzimáticos/síntesis química , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Animales , Antineoplásicos/farmacología , Bencimidazoles/farmacología , Línea Celular Tumoral , Química Farmacéutica/métodos , ADN/química , Reparación del ADN , Diseño de Fármacos , Ensayos de Selección de Medicamentos Antitumorales , Inhibidores Enzimáticos/farmacología , Cinética , Ratones , Trasplante de Neoplasias , Transcripción Genética

RESUMEN

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.

Asunto(s)

Bencimidazoles/química , Bencimidazoles/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Melanoma Experimental/tratamiento farmacológico , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Cisplatino/uso terapéutico , Dacarbazina/análogos & derivados , Dacarbazina/uso terapéutico , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Humanos , Ratones , Relación Estructura-Actividad , Temozolomida , Trasplante Heterólogo , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

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.

Asunto(s)

Hipotensión/inducido químicamente , Indazoles/síntesis química , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Pirazoles/síntesis química , Piridinas/síntesis química , Administración Oral , Animales , Disponibilidad Biológica , Cristalografía por Rayos X , Perros , Indazoles/efectos adversos , Indazoles/farmacología , Ratones , Modelos Moleculares , Conformación Proteica , Ramos Subendocárdicos/efectos de los fármacos , Ramos Subendocárdicos/fisiología , Pirazoles/efectos adversos , Pirazoles/farmacología , Piridinas/efectos adversos , Piridinas/farmacología , Ratas , Estereoisomerismo , Relación Estructura-Actividad

RESUMEN

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.

Asunto(s)

Inhibidores Enzimáticos/farmacología , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Pirazoles/síntesis química , Piridinas/síntesis química , Cristalografía por Rayos X , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/patología , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Pirazoles/química , Pirazoles/farmacología , Piridinas/química , Piridinas/farmacología , Relación Estructura-Actividad , Células Tumorales Cultivadas/efectos de los fármacos

RESUMEN

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.

Asunto(s)

Indoles/química , Neoplasias/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Piridinas/química , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Ratones , Modelos Moleculares , Estructura Molecular , Oxindoles , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/química , Estereoisomerismo , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de Xenoinjerto

RESUMEN

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.

Asunto(s)

Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Isoquinolinas/química , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Piridinas/química , Piridinas/farmacología , Animales , Antineoplásicos/química , Línea Celular Tumoral , Cristalografía por Rayos X , Humanos , Ratones , Estructura Molecular , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Piridinas/síntesis química , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de Xenoinjerto