RESUMEN
The androgen receptor is a major driver of prostate cancer and inhibition of its transcriptional activity using competitive antagonists, such as enzalutamide remains a frontline therapy for prostate cancer management. However, the majority of patients eventually develop drug resistance. We propose that targeting the androgen receptor for degradation via Proteolysis Targeting Chimeras (PROTACs) will be a better therapeutic strategy for targeting androgen receptor signaling in prostate cancer cells. Here we perform a head-to-head comparison between a currently approved androgen receptor antagonist enzalutamide, and its PROTAC derivative, ARCC-4, across different cellular models of prostate cancer drug resistance. ARCC-4 is a low-nanomolar androgen receptor degrader able to degrade about 95% of cellular androgen receptors. ARCC-4 inhibits prostate tumor cell proliferation, degrades clinically relevant androgen receptor point mutants and unlike enzalutamide, retains antiproliferative effect in a high androgen environment. Thus, ARCC-4 exemplifies how protein degradation can address the drug resistance hurdles of enzalutamide.
RESUMEN
Proteolysis targeting chimeras (PROTACs) are bifunctional molecules that recruit an E3 ligase to a target protein to facilitate ubiquitination and subsequent degradation of that protein. While the field of targeted degraders is still relatively young, the potential for this modality to become a differentiated and therapeutic reality is strong, such that both academic and pharmaceutical institutions are now entering this interesting area of research. In this article, we describe a broadly applicable process for identifying degrader hits based on the serine/threonine kinase TANK-binding kinase 1 (TBK1) and have generalized the key structural elements associated with degradation activities. Compound 3i is a potent hit (TBK1 DC50 = 12 nM, Dmax = 96%) with excellent selectivity against a related kinase IKKε, which was further used as a chemical tool to assess TBK1 as a target in mutant K-Ras cancer cells.
Asunto(s)
Proteínas Serina-Treonina Quinasas/metabolismo , Proteolisis/efectos de los fármacos , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/metabolismo , Línea Celular , Proliferación Celular/efectos de los fármacos , Técnicas de Química Sintética , Polarización de Fluorescencia , Genes ras , Humanos , Quinasa I-kappa B/genética , Quinasa I-kappa B/metabolismo , Estructura Molecular , Mutación , Proteínas Serina-Treonina Quinasas/genética , Interferencia de ARN , Relación Estructura-Actividad , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/química , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/genéticaRESUMEN
Proteolysis targeting chimera (PROTAC) technology has emerged over the last two decades as a powerful tool for targeted degradation of endogenous proteins. Herein we describe the development of PROTACs for receptor tyrosine kinases, a protein family yet to be targeted for induced protein degradation. The use of VHL-recruiting PROTACs against this protein family reveals several advantages of degradation over inhibition alone: direct comparisons of fully functional, target-degrading PROTACs with target-inhibiting variants that contain an inactivated E3 ligase-recruiting ligand show that degradation leads to more potent inhibition of cell proliferation and a more durable and sustained downstream signaling response, and thus addresses the kinome rewiring challenge seen with many receptor tyrosine kinase inhibitors. Combined, these findings demonstrate the ability to target receptor tyrosine kinases for degradation using the PROTAC technology and outline the advantages of this degradation-based approach.
Asunto(s)
Inhibidores Enzimáticos , Proteolisis , Proteínas Tirosina Quinasas Receptoras , Ubiquitina-Proteína Ligasas , Humanos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Ligandos , Proteínas Tirosina Quinasas Receptoras/antagonistas & inhibidores , Proteínas Tirosina Quinasas Receptoras/metabolismo , Ubiquitina-Proteína Ligasas/antagonistas & inhibidores , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Prostate cancer has the second highest incidence among cancers in men worldwide and is the second leading cause of cancer deaths of men in the United States. Although androgen deprivation can initially lead to remission, the disease often progresses to castration-resistant prostate cancer (CRPC), which is still reliant on androgen receptor (AR) signaling and is associated with a poor prognosis. Some success against CRPC has been achieved by drugs that target AR signaling, but secondary resistance invariably emerges, and new therapies are urgently needed. Recently, inhibitors of bromodomain and extra-terminal (BET) family proteins have shown growth-inhibitory activity in preclinical models of CRPC. Here, we demonstrate that ARV-771, a small-molecule pan-BET degrader based on proteolysis-targeting chimera (PROTAC) technology, demonstrates dramatically improved efficacy in cellular models of CRPC as compared with BET inhibition. Unlike BET inhibitors, ARV-771 results in suppression of both AR signaling and AR levels and leads to tumor regression in a CRPC mouse xenograft model. This study is, to our knowledge, the first to demonstrate efficacy with a small-molecule BET degrader in a solid-tumor malignancy and potentially represents an important therapeutic advance in the treatment of CRPC.
Asunto(s)
Antineoplásicos/administración & dosificación , Proteínas Nucleares/metabolismo , Neoplasias de la Próstata Resistentes a la Castración/tratamiento farmacológico , Neoplasias de la Próstata Resistentes a la Castración/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas de Unión al ARN/metabolismo , Factores de Transcripción/metabolismo , Animales , Proteínas de Ciclo Celular , Línea Celular Tumoral , Humanos , Masculino , Ratones , Proteínas Nucleares/genética , Neoplasias de la Próstata Resistentes a la Castración/genética , Proteínas Serina-Treonina Quinasas/genética , Proteolisis , Proteínas de Unión al ARN/genética , Receptores Androgénicos/genética , Receptores Androgénicos/metabolismo , Transducción de Señal/efectos de los fármacos , Factores de Transcripción/genéticaRESUMEN
BRD4, a bromodomain and extraterminal domain (BET) family member, is an attractive target in multiple pathological settings, particularly cancer. While BRD4 inhibitors have shown some promise in MYC-driven malignancies such as Burkitt's lymphoma (BL), we show that BRD4 inhibitors lead to robust BRD4 protein accumulation, which may account for their limited suppression of MYC expression, modest antiproliferative activity, and lack of apoptotic induction. To address these limitations we designed ARV-825, a hetero-bifunctional PROTAC (Proteolysis Targeting Chimera) that recruits BRD4 to the E3 ubiquitin ligase cereblon, leading to fast, efficient, and prolonged degradation of BRD4 in all BL cell lines tested. Consequently, ARV-825 more effectively suppresses c-MYC levels and downstream signaling than small-molecule BRD4 inhibitors, resulting in more effective cell proliferation inhibition and apoptosis induction in BL. Our findings provide strong evidence that cereblon-based PROTACs provide a better and more efficient strategy in targeting BRD4 than traditional small-molecule inhibitors.
Asunto(s)
Azepinas/farmacología , Proteínas Nucleares/metabolismo , Péptido Hidrolasas/metabolismo , Transducción de Señal/efectos de los fármacos , Talidomida/análogos & derivados , Factores de Transcripción/metabolismo , Acetanilidas/toxicidad , Proteínas Adaptadoras Transductoras de Señales , Apoptosis/efectos de los fármacos , Azepinas/química , Azepinas/toxicidad , Proteínas de Ciclo Celular , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Compuestos Heterocíclicos con 3 Anillos/toxicidad , Humanos , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-myc/metabolismo , Talidomida/química , Talidomida/farmacología , Factores de Transcripción/antagonistas & inhibidores , Triazoles/toxicidad , Ubiquitina-Proteína LigasasRESUMEN
The discovery and potency optimization of a series of 7-aminofuro[2,3-c]pyridine inhibitors of TAK1 is described. Micromolar hits taken from high-throughput screening were optimized for biochemical and cellular mechanistic potency to ~10nM, as exemplified by compound 12az. Application of structure-based drug design aided by co-crystal structures of TAK1 with inhibitors significantly shortened the number of iterations required for the optimization.
Asunto(s)
Quinasas Quinasa Quinasa PAM/antagonistas & inhibidores , Piridinas , Aminas/síntesis química , Aminas/química , Aminas/farmacología , Animales , Cristalografía por Rayos X , Diseño de Fármacos , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/farmacología , Furanos/síntesis química , Furanos/química , Furanos/farmacología , Humanos , Concentración 50 Inhibidora , Ratones , Estructura Molecular , Neoplasias/tratamiento farmacológico , Piridinas/síntesis química , Piridinas/farmacocinética , Piridinas/farmacología , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The kinase selectivity and pharmacokinetic optimization of a series of 7-aminofuro[2,3-c]pyridine inhibitors of TAK1 is described. The intersection of insights from molecular modeling, computational prediction of metabolic sites, and in vitro metabolite identification studies resulted in a simple and unique solution to both of these problems. These efforts culminated in the discovery of compound 13a, a potent, relatively selective inhibitor of TAK1 with good pharmacokinetic properties in mice, which was active in an in vivo model of ovarian cancer.
Asunto(s)
Inhibidores Enzimáticos , Quinasas Quinasa Quinasa PAM/antagonistas & inhibidores , Piridinas , Aminas/síntesis química , Aminas/química , Aminas/farmacología , Animales , Cristalografía por Rayos X , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/farmacología , Furanos/síntesis química , Furanos/química , Furanos/farmacología , Humanos , Concentración 50 Inhibidora , Quinasas Quinasa Quinasa PAM/metabolismo , Ratones , Estructura Molecular , Neoplasias/tratamiento farmacológico , Fosfotransferasas/química , Fosfotransferasas/metabolismo , Piridinas/síntesis química , Piridinas/farmacocinética , Piridinas/farmacología , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
This Letter describes the medicinal chemistry effort towards a series of novel imidazo[1,5-a]pyrazine derived inhibitors of ACK1. Virtual screening led to the discovery of the initial hit, and subsequent exploration of structure-activity relationships and optimization of drug metabolism and pharmacokinetic properties led to the identification of potent, selective and orally bioavailable ACK1 inhibitors.
Asunto(s)
Imidazoles/química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Pirazinas/química , Administración Oral , Animales , Humanos , Imidazoles/farmacocinética , Imidazoles/farmacología , Ratones , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacocinética , Pirazinas/farmacocinética , Pirazinas/farmacología , Relación Estructura-ActividadRESUMEN
The phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway is frequently activated in human cancers, and mTOR is a clinically validated target. mTOR forms two distinct multiprotein complexes, mTORC1 and mTORC2, which regulate cell growth, metabolism, proliferation, and survival. Rapamycin and its analogues partially inhibit mTOR through allosteric binding to mTORC1, but not mTORC2, and have shown clinical utility in certain cancers. Here, we report the preclinical characterization of OSI-027, a selective and potent dual inhibitor of mTORC1 and mTORC2 with biochemical IC(50) values of 22 nmol/L and 65 nmol/L, respectively. OSI-027 shows more than 100-fold selectivity for mTOR relative to PI3Kα, PI3Kß, PI3Kγ, and DNA-PK. OSI-027 inhibits phosphorylation of the mTORC1 substrates 4E-BP1 and S6K1 as well as the mTORC2 substrate AKT in diverse cancer models in vitro and in vivo. OSI-027 and OXA-01 (close analogue of OSI-027) potently inhibit proliferation of several rapamycin-sensitive and -insensitive nonengineered and engineered cancer cell lines and also, induce cell death in tumor cell lines with activated PI3K-AKT signaling. OSI-027 shows concentration-dependent pharmacodynamic effects on phosphorylation of 4E-BP1 and AKT in tumor tissue with resulting tumor growth inhibition. OSI-027 shows robust antitumor activity in several different human xenograft models representing various histologies. Furthermore, in COLO 205 and GEO colon cancer xenograft models, OSI-027 shows superior efficacy compared with rapamycin. Our results further support the important role of mTOR as a driver of tumor growth and establish OSI-027 as a potent anticancer agent. OSI-027 is currently in phase I clinical trials in cancer patients.
Asunto(s)
Imidazoles/farmacología , Inhibidores de Proteínas Quinasas/farmacología , Proteínas/antagonistas & inhibidores , Sirolimus/farmacología , Factores de Transcripción/antagonistas & inhibidores , Triazinas/farmacología , Animales , Apoptosis/efectos de los fármacos , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Femenino , Células HeLa , Humanos , Imidazoles/química , Imidazoles/farmacocinética , Diana Mecanicista del Complejo 1 de la Rapamicina , Ratones , Ratones Desnudos , Complejos Multiproteicos , Fosfohidrolasa PTEN/genética , Fosfohidrolasa PTEN/metabolismo , Fosforilación/efectos de los fármacos , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacocinética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Serina-Treonina Quinasas TOR , Triazinas/química , Triazinas/farmacocinética , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The discovery and optimization of a series of imidazo[1,5-a]pyrazine inhibitors of mTOR is described. HTS hits were optimized for potency, selectivity and metabolic stability to provide the orally bioavailable proof of concept compound 4c that demonstrated target inhibition in vivo and concomitant inhibition of tumor growth in an MDA-MB-231 xenograft model.
Asunto(s)
Imidazoles/farmacología , Proteínas/antagonistas & inhibidores , Pirazinas/farmacología , Factores de Transcripción/antagonistas & inhibidores , Administración Oral , Línea Celular Tumoral , Humanos , Imidazoles/administración & dosificación , Diana Mecanicista del Complejo 1 de la Rapamicina , Modelos Moleculares , Complejos Multiproteicos , Pirazinas/administración & dosificación , Serina-Treonina Quinasas TOR , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
A complex of RON(M1254T) with AMP-PNP and Mg(2+) reveals a substratelike positioning of Tyr1238 as well as likely catalysis-competent placement of the AMP-PNP and Mg(2+) components and indicates a tendency for cis phosphorylation. The structure shows how the oncogenic mutation may cause the constitutive activation and suggests a mechanistic hypothesis for the autophosphorylation of receptor tyrosine kinases.
Asunto(s)
Proteínas Tirosina Quinasas Receptoras/química , Proteínas Tirosina Quinasas Receptoras/metabolismo , Adenilil Imidodifosfato , Fosforilación , Fosfotransferasas , Proteínas Tirosina Quinasas Receptoras/genéticaRESUMEN
The PI3K/Akt/mTOR pathway is frequently activated in human cancers, and mTOR is a clinically validated target for therapeutic intervention in this pathway. The discovery of the involvement of rapamycin-insensitive mTOR complex 2 (mTORC2) in the activation of Akt, combined with the limited clinical antitumor activity of mTOR complex 1 (mTORC1)-directed rapamycin analogs, have led to the discovery of ATP-competitive selective inhibitors of the mTOR kinase that inhibit the function of both mTORC1 and mTORC2. This review describes progress in the identification of selective and novel inhibitors of mTORC1/2, focusing on the profile of inhibitors that are in clinical development.
Asunto(s)
Terapia Molecular Dirigida , Neoplasias/tratamiento farmacológico , Proteínas/antagonistas & inhibidores , Transducción de Señal/efectos de los fármacos , Factores de Transcripción/antagonistas & inhibidores , Animales , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina , Complejos Multiproteicos , Neoplasias/metabolismo , Proteínas/metabolismo , Transducción de Señal/fisiología , Serina-Treonina Quinasas TOR , Factores de Transcripción/metabolismoRESUMEN
Imidazo[1,5-a]pyrazines 1 undergo regioselective C3-metalation and C5/C3-dimetalation to afford a range of functionalized derivatives 2a-2g (Table 1 ), and 4a-4d (Table 2 ). Under similar conditions, the C3-methyl derivatives 2a and 5 undergo surprising regioselective C5-deprotonation to afford, after electrophile quench, products 4b and 6a-6p (Table 3 ), results that are rationalized by quantum mechanical calculations. Benzamide 7b, obtained from such metalation chemistry followed by Suzuki cross coupling, undergoes directed remote metalation-cyclization to afford 8, representing the hitherto unknown triazadibenzo[cd,f]azulen-7(6H)-one tricyclic ring system.
Asunto(s)
Imidazoles/síntesis química , Metales/química , Pirazinas/síntesis química , Ciclización , Imidazoles/química , Estructura Molecular , Pirazinas/química , Teoría Cuántica , EstereoisomerismoRESUMEN
A general and efficient synthesis of 5-aryl imidazo[1,5- a]pyrazines by palladium-catalyzed coupling of the corresponding 8-substituted derivatives with aryl halides is described. The scope of this new reaction for the imidazo[1,5- a]pyrazine ring system was explored using three readily available 8-substituted precursors, X = NH2, NMe2, and OMe, as well as 8-aryl derivatives, X = Ar'. On the basis of these results as well as studies using a deuterated derivative, a Heck-like mechanism is proposed for this transformation.
Asunto(s)
Hidrocarburos Bromados/química , Imidazoles/síntesis química , Paladio/química , Pirazinas/síntesis química , Catálisis , Técnicas Químicas Combinatorias , Imidazoles/química , Estructura Molecular , Pirazinas/química , EstereoisomerismoRESUMEN
A highly effective one-pot Friedländer quinoline synthesis using inexpensive reagents has been developed. o-Nitroarylcarbaldehydes were reduced to o-aminoarylcarbaldehydes with iron in the presence of catalytic HCl (aq.) and subsequently condensed in situ with aldehydes or ketones to form mono- or di-substituted quinolines in high yields (66-100%).
Asunto(s)
Aldehídos/química , Benzaldehídos/química , Quinolinas/síntesis química , Hierro/química , Cetonas/química , Estructura Molecular , Oxidación-Reducción , Quinolinas/químicaRESUMEN
OSI-930 is a novel inhibitor of the receptor tyrosine kinases Kit and kinase insert domain receptor (KDR), which is currently being evaluated in clinical studies. OSI-930 selectively inhibits Kit and KDR with similar potency in intact cells and also inhibits these targets in vivo following oral dosing. We have investigated the relationships between the potency observed in cell-based assays in vitro, the plasma exposure levels achieved following oral dosing, the time course of target inhibition in vivo, and antitumor activity of OSI-930 in tumor xenograft models. In the mutant Kit-expressing HMC-1 xenograft model, prolonged inhibition of Kit was achieved at oral doses between 10 and 50 mg/kg and this dose range was associated with antitumor activity. Similarly, prolonged inhibition of wild-type Kit in the NCI-H526 xenograft model was observed at oral doses of 100 to 200 mg/kg, which was the dose level associated with significant antitumor activity in this model as well as in the majority of other xenograft models tested. The data suggest that antitumor activity of OSI-930 in mouse xenograft models is observed at dose levels that maintain a significant level of inhibition of the molecular targets of OSI-930 for a prolonged period. Furthermore, pharmacokinetic evaluation of the plasma exposure levels of OSI-930 at these effective dose levels provides an estimate of the target plasma concentrations that may be required to achieve prolonged inhibition of Kit and KDR in humans and which would therefore be expected to yield a therapeutic benefit in future clinical evaluations of OSI-930.