RESUMEN
Human DNA polymerase theta (Polθ), which is essential for microhomology-mediated DNA double strand break repair, has been proposed as an attractive target for the treatment of BRCA deficient and other DNA repair pathway defective cancers. As previously reported, we recently identified the first selective small molecule Polθ in vitro probe, 22 (ART558), which recapitulates the phenotype of Polθ loss, and in vivo probe, 43 (ART812), which is efficacious in a model of PARP inhibitor resistant TNBC in vivo. Here we describe the discovery, biochemical and biophysical characterization of these probes including small molecule ligand co-crystal structures with Polθ. The crystallographic data provides a basis for understanding the unique mechanism of inhibition of these compounds which is dependent on stabilization of a "closed" enzyme conformation. Additionally, the structural biology platform provided a basis for rational optimization based primarily on reduced ligand conformational flexibility.
Asunto(s)
Reparación del ADN por Unión de Extremidades , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Humanos , Ligandos , ADN/metabolismo , ADN Polimerasa thetaRESUMEN
Phosphatidyl inositol (4,5)-bisphosphate (PI(4,5)P2) plays several key roles in human biology and the lipid kinase that produces PI(4,5)P2, PIP5K, has been hypothesized to provide a potential therapeutic target of interest in the treatment of cancers. To better understand and explore the role of PIP5K in human cancers there remains an urgent need for potent and specific PIP5K inhibitor molecules. Following a high throughput screen of the AstraZeneca collection, a novel, moderately potent and selective inhibitor of PIP5K, 1, was discovered. Detailed exploration of the SAR for this novel scaffold resulted in the considerable optimization of both potency for PIP5K, and selectivity over the closely related kinase PI3Kα, as well as identifying several opportunities for the continued optimization of drug-like properties. As a result, several high quality in vitro tool compounds were identified (8, 20 and 25) that demonstrate the desired biochemical and cellular profiles required to aid better understanding of this complex area of biology.
Asunto(s)
Amidas/farmacología , Inhibidores Enzimáticos/farmacología , Fosfotransferasas (Aceptor de Grupo Alcohol)/antagonistas & inhibidores , Amidas/química , Amidas/metabolismo , Animales , Células CACO-2 , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/metabolismo , Humanos , Microsomas Hepáticos/química , Microsomas Hepáticos/metabolismo , Estructura Molecular , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Ratas , Relación Estructura-ActividadRESUMEN
KRAS-mutant colorectal cancers are resistant to therapeutics, presenting a significant problem for â¼40% of cases. Rapalogs, which inhibit mTORC1 and thus protein synthesis, are significantly less potent in KRAS-mutant colorectal cancer. Using Kras-mutant mouse models and mouse- and patient-derived organoids, we demonstrate that KRAS with G12D mutation fundamentally rewires translation to increase both bulk and mRNA-specific translation initiation. This occurs via the MNK/eIF4E pathway culminating in sustained expression of c-MYC. By genetic and small-molecule targeting of this pathway, we acutely sensitize KRASG12D models to rapamycin via suppression of c-MYC. We show that 45% of colorectal cancers have high signaling through mTORC1 and the MNKs, with this signature correlating with a 3.5-year shorter cancer-specific survival in a subset of patients. This work provides a c-MYC-dependent cotargeting strategy with remarkable potency in multiple Kras-mutant mouse models and metastatic human organoids and identifies a patient population that may benefit from its clinical application. SIGNIFICANCE: KRAS mutation and elevated c-MYC are widespread in many tumors but remain predominantly untargetable. We find that mutant KRAS modulates translation, culminating in increased expression of c-MYC. We describe an effective strategy targeting mTORC1 and MNK in KRAS-mutant mouse and human models, pathways that are also commonly co-upregulated in colorectal cancer.This article is highlighted in the In This Issue feature, p. 995.
Asunto(s)
Neoplasias Colorrectales/genética , Factor 4E Eucariótico de Iniciación/efectos de los fármacos , Péptidos y Proteínas de Señalización Intracelular/efectos de los fármacos , Inhibidores mTOR/farmacología , Proteínas Serina-Treonina Quinasas/efectos de los fármacos , Animales , Neoplasias Colorrectales/metabolismo , Modelos Animales de Enfermedad , Factor 4E Eucariótico de Iniciación/metabolismo , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ratones , Ratones Endogámicos C57BL , Fosforilación , Proteínas Serina-Treonina Quinasas/metabolismoRESUMEN
A novel series of EP4 agonists and antagonists have been identified, and then used to validate their potential in the treatment of inflammatory pain. This paper describes these novel ligands and their activity within a number of pre-clinical models of pain, ultimately leading to the identification of the EP4 partial agonist GSK726701A.
Asunto(s)
Antiinflamatorios/química , Isoindoles/química , Subtipo EP4 de Receptores de Prostaglandina E/agonistas , Animales , Antiinflamatorios/farmacocinética , Antiinflamatorios/uso terapéutico , Células Sanguíneas/citología , Células Sanguíneas/efectos de los fármacos , Células Sanguíneas/metabolismo , Dinoprostona/química , Dinoprostona/uso terapéutico , Evaluación Preclínica de Medicamentos , Semivida , Humanos , Concentración 50 Inhibidora , Isoindoles/farmacocinética , Isoindoles/uso terapéutico , Lipopolisacáridos/farmacología , Dolor/tratamiento farmacológico , Dolor/patología , Dolor/veterinaria , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/metabolismo , Ratas , Subtipo EP4 de Receptores de Prostaglandina E/metabolismo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The discovery and optimisation of novel, potent and selective small molecule inhibitors of the α-isoform of type III phosphatidylinositol-4-kinase (PI4Kα) are described. Lead compounds show cellular activity consistent with their PI4Kα potency inhibiting the accumulation of IP1 after PDGF stimulation and reducing cellular PIP, PIP2 and PIP3 levels. Hence, these compounds are useful in vitro tools to delineate the complex biological pathways involved in signalling through PI4Kα.
Asunto(s)
Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Fosfotransferasas (Aceptor de Grupo Alcohol)/antagonistas & inhibidores , Diseño de Fármacos , Ensayos Analíticos de Alto Rendimiento , Humanos , Fosfatos de Inositol/metabolismo , Antígenos de Histocompatibilidad Menor , Modelos Moleculares , Factor de Crecimiento Derivado de Plaquetas/farmacología , Transducción de Señal/efectos de los fármacos , Bibliotecas de Moléculas Pequeñas , Relación Estructura-ActividadRESUMEN
Two series of inhibitors of type III phosphatidylinositol-4-kinase were identified by high throughput screening and optimised to derive probe compounds that independently and selectively inhibit the α- and the ß-isoforms with no significant activity towards related kinases in the pathway. In a cellular environment, inhibition of the α- but not the ß-subtype led to a reduction in phosphatidylinositol-4-phosphate and phosphatidylinositol-4,5-bisphosphate concentration, causing inhibition of inositol-1-phosphate formation and inhibition of proliferation in a panel of cancer cell lines.