RESUMEN
Approved therapies for hepatitis B virus (HBV) treatment include nucleos(t)ides and interferon alpha (IFN-α) which effectively suppress viral replication, but they rarely lead to cure. Expression of viral proteins, especially surface antigen of the hepatitis B virus (HBsAg) from covalently closed circular DNA (cccDNA) and the integrated genome, is believed to contribute to the persistence of HBV. This work focuses on therapies that target the expression of HBV proteins, in particular HBsAg, which differs from current treatments. Here we describe the identification of AB-452, a dihydroquinolizinone (DHQ) analogue. AB-452 is a potent HBV RNA destabilizer by inhibiting PAPD5/7 proteins in vitro with good in vivo efficacy in a chronic HBV mouse model. AB-452 showed acceptable tolerability in 28-day rat and dog toxicity studies, and a high degree of oral exposure in multiple species. Based on its in vitro and in vivo profiles, AB-452 was identified as a clinical development candidate.
Asunto(s)
Virus de la Hepatitis B , Hepatitis B Crónica , Ratones , Ratas , Animales , Perros , Virus de la Hepatitis B/genética , Antígenos de Superficie de la Hepatitis B , Antivirales/uso terapéutico , Hepatitis B Crónica/tratamiento farmacológico , ARN Viral/genética , Relación Estructura-Actividad , Naftiridinas/farmacología , Naftiridinas/uso terapéutico , ADN Viral/genética , Replicación ViralRESUMEN
The recent COVID-19 pandemic underscored the limitations of currently available direct-acting antiviral treatments against acute respiratory RNA-viral infections and stimulated major research initiatives targeting anticoronavirus agents. Two novel nsp5 protease (MPro) inhibitors have been approved, nirmatrelvir and ensitrelvir, along with two existing nucleos(t)ide analogues repurposed as nsp12 polymerase inhibitors, remdesivir and molnupiravir, but a need still exists for therapies with improved potency and systemic exposure with oral dosing, better metabolic stability, and reduced resistance and toxicity risks. Herein, we summarize our research toward identifying nsp12 inhibitors that led to nucleoside analogues 10e and 10n, which showed favorable pan-coronavirus activity in cell-infection screens, were metabolized to active triphosphate nucleotides in cell-incubation studies, and demonstrated target (nsp12) engagement in biochemical assays.
Asunto(s)
Antivirales , Tratamiento Farmacológico de COVID-19 , Nucleósidos , SARS-CoV-2 , Antivirales/farmacología , Antivirales/química , SARS-CoV-2/efectos de los fármacos , Humanos , Nucleósidos/farmacología , Nucleósidos/química , Animales , Descubrimiento de Drogas , Proteínas no Estructurales Virales/antagonistas & inhibidores , Proteínas no Estructurales Virales/metabolismo , Chlorocebus aethiops , Células Vero , COVID-19/virología , ARN Polimerasa Dependiente de ARN de CoronavirusRESUMEN
Accumulating evidence suggests that autoreactive plasma cells play an important role in systemic lupus erythematosus (SLE). In addition, several proinflammatory cytokines promote autoreactive B cell maturation and autoantibody production. Hence, therapeutic targeting of such cytokine pathways using a selective JAK2 inhibitor, CEP-33779 (JAK2 enzyme IC(50) = 1.3 nM; JAK3 enzyme IC(50)/JAK2 enzyme IC(50) = 65-fold), was tested in two mouse models of SLE. Age-matched, MRL/lpr or BWF1 mice with established SLE or lupus nephritis, respectively, were treated orally with CEP-33779 at 30 mg/kg (MRL/lpr), 55 mg/kg or 100 mg/kg (MRL/lpr and BWF1). Studies included reference standard, dexamethasone (1.5 mg/kg; MRL/lpr), and cyclophosphamide (50 mg/kg; MRL/lpr and BWF1). Treatment with CEP-33779 extended survival and reduced splenomegaly/lymphomegaly. Several serum cytokines were significantly decreased upon treatment including IL-12, IL-17A, IFN-α, IL-1ß, and TNF-α. Anti-nuclear Abs and frequencies of autoantigen-specific, Ab-secreting cells declined upon CEP-33779 treatment. Increased serum complement levels were associated with reduced renal JAK2 activity, histopathology, and spleen CD138(+) plasma cells. The selective JAK2 inhibitor CEP-33779 was able to mitigate several immune parameters associated with SLE advancement, including the protection and treatment of mice with lupus nephritis. These data support the possibility of using potent, orally active, small-molecule inhibitors of JAK2 to treat the debilitative disease SLE.
Asunto(s)
Inhibidores Enzimáticos/uso terapéutico , Janus Quinasa 2/antagonistas & inhibidores , Nefritis Lúpica/tratamiento farmacológico , Células Plasmáticas/efectos de los fármacos , Piridinas/uso terapéutico , Triazoles/uso terapéutico , Administración Oral , Animales , Anticuerpos Antinucleares/sangre , Autoinmunidad/efectos de los fármacos , Autoinmunidad/inmunología , Separación Celular , Citocinas/sangre , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/farmacocinética , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Nefritis Lúpica/inmunología , Nefritis Lúpica/patología , Ratones , Ratones Endogámicos MRL lpr , Células Plasmáticas/inmunología , Piridinas/farmacocinética , Triazoles/farmacocinéticaRESUMEN
A series of macrocyclic calcitonin gene-related peptide (CGRP) receptor antagonists identified using structure-based design principles, exemplified by HTL0028016 (1) and HTL0028125 (2), is described. Structural characterization by X-ray crystallography of the interaction of two of the macrocycle antagonists with the CGRP receptor ectodomain is described, along with structure-activity relationships associated with point changes to the macrocyclic antagonists. The identification of non-peptidic/natural product-derived, macrocyclic ligands for a G protein coupled receptor (GPCR) is noteworthy.
Asunto(s)
Receptores de Péptido Relacionado con el Gen de Calcitonina , Receptores Acoplados a Proteínas G , Proteína Similar al Receptor de Calcitonina/química , Proteína Similar al Receptor de Calcitonina/metabolismo , Cristalografía por Rayos X , Ligandos , Receptores de Péptido Relacionado con el Gen de Calcitonina/química , Receptores de Péptido Relacionado con el Gen de Calcitonina/metabolismo , Receptores Acoplados a Proteínas G/metabolismoRESUMEN
The synthesis and biological evaluation of potent and selective anaplastic lymphoma kinase (ALK) inhibitors from a novel class of 2,4-diaminopyrimidines, incorporating 2,3,4,5-tetrahydro-benzo[d]azepine fragments, is described. An orally bioavailable analogue (18) that displayed antitumor efficacy in ALCL xenograft models in mice was identified and extensively profiled.
Asunto(s)
Benzazepinas/química , Linfoma Anaplásico de Células Grandes/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/química , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Pirimidinas/química , Administración Oral , Quinasa de Linfoma Anaplásico , Animales , Benzazepinas/farmacocinética , Benzazepinas/uso terapéutico , Ratones , Inhibidores de Proteínas Quinasas/farmacocinética , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Tirosina Quinasas/metabolismo , Pirimidinas/farmacocinética , Pirimidinas/uso terapéutico , Ratas , Ratas Sprague-Dawley , Proteínas Tirosina Quinasas Receptoras , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Members of the JAK family of nonreceptor tyrosine kinases play a critical role in the growth and progression of many cancers and in inflammatory diseases. JAK2 has emerged as a leading therapeutic target for oncology, providing a rationale for the development of a selective JAK2 inhibitor. A program to optimize selective JAK2 inhibitors to combat cancer while reducing the risk of immune suppression associated with JAK3 inhibition was undertaken. The structure-activity relationships and biological evaluation of a novel series of compounds based on a 1,2,4-triazolo[1,5-a]pyridine scaffold are reported. Para substitution on the aryl at the C8 position of the core was optimum for JAK2 potency (17). Substitution at the C2 nitrogen position was required for cell potency (21). Interestingly, meta substitution of C2-NH-aryl moiety provided exceptional selectivity for JAK2 over JAK3 (23). These efforts led to the discovery of CEP-33779 (29), a novel, selective, and orally bioavailable inhibitor of JAK2.
Asunto(s)
Antineoplásicos/síntesis química , Janus Quinasa 2/antagonistas & inhibidores , Piridinas/síntesis química , Triazoles/síntesis química , Administración Oral , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Disponibilidad Biológica , Línea Celular , Cristalografía por Rayos X , Perros , Humanos , Ratones , Ratones Desnudos , Microsomas Hepáticos/metabolismo , Modelos Moleculares , Estructura Molecular , Piridinas/química , Piridinas/farmacología , Ratas , Relación Estructura-Actividad , Triazoles/química , Triazoles/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Oxygen dependent quenching of phosphorescence allows for non-invasive measurements of oxygen in tissue. We have designed and constructed a novel multi-frequency instrument for measurement of phosphorescence lifetimes and developed algorithms for determining the distribution of oxygen (oxygen histogram) in the microvasculature of tissue with good temporal resolution (Vinogradov et al., 2002, Compar. Biochem. A, these proceedings). This technology, in combination with a new water soluble near infra red phosphor (Oxyphor G2), was used to examine the oxygenation of subcutaneous Q7 tumors grown on the flank of Buffalo rats and their response to giving the rats oxygen or carbogen to breathe. Phosphorescence was measured using excitation at 635 nm and emission at >700 nm (the phosphorescence maximum is near 800 nm). The excitation and collection light guides were placed on the surface of the skin of the anesthetized animals separated by approximately 0.8 cm. A 6 x 6 or 7 x 7 grid (approx. 4 cm x 4 cm) was drawn on the flank and oxygen histograms were measured in each square, providing 'images' of the oxygen distribution in the tissue. This procedure determines the tissue oxygen distribution at each position in the grid. Regions of relative hypoxia (associated with the tumor) can be readily localized and the extent of hypoxia quantitatively evaluated.