RESUMEN
The ubiquitously expressed protein tyrosine phosphatase SHP2 is required for signaling downstream of receptor tyrosine kinases (RTKs) and plays a role in regulating many cellular processes. Genetic knockdown and pharmacological inhibition of SHP2 suppresses RAS/MAPK signaling and inhibit the proliferation of RTK-driven cancer cell lines. Here, we describe the first reported fragment-to-lead campaign against SHP2, where X-ray crystallography and biophysical techniques were used to identify fragments binding to multiple sites on SHP2. Structure-guided optimization, including several computational methods, led to the discovery of two structurally distinct series of SHP2 inhibitors binding to the previously reported allosteric tunnel binding site (Tunnel Site). One of these series was advanced to a low-nanomolar lead that inhibited tumor growth when dosed orally to mice bearing HCC827 xenografts. Furthermore, a third series of SHP2 inhibitors was discovered binding to a previously unreported site, lying at the interface of the C-terminal SH2 and catalytic domains.
Asunto(s)
Neoplasias , Proteína Tirosina Fosfatasa no Receptora Tipo 11 , Humanos , Ratones , Animales , Transducción de Señal , Proteínas Tirosina Quinasas Receptoras/metabolismo , Sitio AlostéricoRESUMEN
This article discusses the reactivity of 6-azaindazole (1) and 2,6-naphthyridine (2), proposed to be "heteroaromatic rings of the future," which would be useful for fragment-based drug discovery (FBDD) campaigns, developing growth vectors for fragment elaboration by selectively functionalizing different positions on the rings. The pyridone oxygens and pyrazole nitrogen can be functionalized selectively. Arylation at the α-carbon of the pyridone moiety was achieved by a transition metal-free radical cross-coupling using aryl hydrazines. This method proceeded under mild conditions without the need for protection of the hydroxypyridine. Additionally, we developed a method for the regioselective C-3 functionalization of heterocycle 1via N-sulfonamide rearrangement. This method involved a novel regioselective base-mediated N-C migration of the N-1 sulfonamide to yield the C-3 sulfone. This procedure is also applicable for indazole C-3 functionalization and mechanistic studies of the rearrangement suggest that an intermolecular process is involved. These reactions enable the fragment elaboration of heterocycles 1 and 2 in several growth vectors to facilitate their use in FBDD.
Asunto(s)
Carbono , Nitrógeno , Catálisis , Hidrazinas , Indazoles , Naftiridinas , Pirazoles , Piridonas , Sulfonamidas , SulfonasRESUMEN
Aberrant activation of the mitogen-activated protein kinase pathway frequently drives tumor growth, and the ERK1/2 kinases are positioned at a key node in this pathway, making them important targets for therapeutic intervention. Recently, a number of ERK1/2 inhibitors have been advanced to investigational clinical trials in patients with activating mutations in B-Raf proto-oncogene or Ras. Here, we describe the discovery of the clinical candidate ASTX029 (15) through structure-guided optimization of our previously published isoindolinone lead (7). The medicinal chemistry campaign focused on addressing CYP3A4-mediated metabolism and maintaining favorable physicochemical properties. These efforts led to the identification of ASTX029, which showed the desired pharmacological profile combining ERK1/2 inhibition with suppression of phospho-ERK1/2 (pERK) levels, and in addition, it possesses suitable preclinical pharmacokinetic properties predictive of once daily dosing in humans. ASTX029 is currently in a phase I-II clinical trial in patients with advanced solid tumors.
Asunto(s)
Antineoplásicos/uso terapéutico , Indoles/uso terapéutico , Proteína Quinasa 1 Activada por Mitógenos/antagonistas & inhibidores , Neoplasias/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirimidinas/uso terapéutico , Animales , Antineoplásicos/síntesis química , Antineoplásicos/metabolismo , Antineoplásicos/farmacocinética , Cristalografía por Rayos X , Perros , Humanos , Indoles/síntesis química , Indoles/metabolismo , Indoles/farmacocinética , Masculino , Ratones Endogámicos BALB C , Proteína Quinasa 1 Activada por Mitógenos/química , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Estructura Molecular , Fosforilación/efectos de los fármacos , Unión Proteica , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/metabolismo , Inhibidores de Proteínas Quinasas/farmacocinética , Proto-Oncogenes Mas , Pirimidinas/síntesis química , Pirimidinas/metabolismo , Pirimidinas/farmacocinética , Ratas Sprague-Dawley , Ratas Wistar , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Inhibitor of apoptosis proteins (IAPs) are promising anticancer targets, given their roles in the evasion of apoptosis. Several peptidomimetic IAP antagonists, with inherent selectivity for cellular IAP (cIAP) over X-linked IAP (XIAP), have been tested in the clinic. A fragment screening approach followed by structure-based optimization has previously been reported that resulted in a low-nanomolar cIAP1 and XIAP antagonist lead molecule with a more balanced cIAP-XIAP profile. We now report the further structure-guided optimization of the lead, with a view to improving the metabolic stability and cardiac safety profile, to give the nonpeptidomimetic antagonist clinical candidate 27 (ASTX660), currently being tested in a phase 1/2 clinical trial (NCT02503423).
Asunto(s)
Antineoplásicos/farmacología , Compuestos Heterocíclicos con 2 Anillos/farmacología , Piperazinas/farmacología , Proteína Inhibidora de la Apoptosis Ligada a X/antagonistas & inhibidores , Administración Oral , Animales , Antineoplásicos/química , Antineoplásicos/farmacocinética , Línea Celular Tumoral , Cristalografía por Rayos X , Canal de Potasio ERG1/antagonistas & inhibidores , Compuestos Heterocíclicos con 2 Anillos/química , Compuestos Heterocíclicos con 2 Anillos/farmacocinética , Humanos , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Macaca fascicularis , Masculino , Ratones Endogámicos BALB C , Piperazinas/química , Piperazinas/farmacocinética , Ratas Sprague-Dawley , Relación Estructura-Actividad , Proteína Inhibidora de la Apoptosis Ligada a X/química , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Aberrant activation of the MAPK pathway drives cell proliferation in multiple cancers. Inhibitors of BRAF and MEK kinases are approved for the treatment of BRAF mutant melanoma, but resistance frequently emerges, often mediated by increased signaling through ERK1/2. Here, we describe the fragment-based generation of ERK1/2 inhibitors that block catalytic phosphorylation of downstream substrates such as RSK but also modulate phosphorylation of ERK1/2 by MEK without directly inhibiting MEK. X-ray crystallographic and biophysical fragment screening followed by structure-guided optimization and growth from the hinge into a pocket proximal to the C-α helix afforded highly potent ERK1/2 inhibitors with excellent kinome selectivity. In BRAF mutant cells, the lead compound suppresses pRSK and pERK levels and inhibits proliferation at low nanomolar concentrations. The lead exhibits tumor regression upon oral dosing in BRAF mutant xenograft models, providing a promising basis for further optimization toward clinical pERK1/2 modulating ERK1/2 inhibitors.
Asunto(s)
Biocatálisis/efectos de los fármacos , Descubrimiento de Drogas , Proteína Quinasa 1 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Administración Oral , Animales , Disponibilidad Biológica , Línea Celular Tumoral , Humanos , Ratones , Proteína Quinasa 1 Activada por Mitógenos/química , Proteína Quinasa 3 Activada por Mitógenos/química , Modelos Moleculares , Fosforilación/efectos de los fármacos , Conformación Proteica , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacocinéticaRESUMEN
XIAP and cIAP1 are members of the inhibitor of apoptosis protein (IAP) family and are key regulators of anti-apoptotic and pro-survival signaling pathways. Overexpression of IAPs occurs in various cancers and has been associated with tumor progression and resistance to treatment. Structure-based drug design (SBDD) guided by structural information from X-ray crystallography, computational studies, and NMR solution conformational analysis was successfully applied to a fragment-derived lead resulting in AT-IAP, a potent, orally bioavailable, dual antagonist of XIAP and cIAP1 and a structurally novel chemical probe for IAP biology.
Asunto(s)
Compuestos Heterocíclicos con 2 Anillos/química , Compuestos Heterocíclicos con 2 Anillos/farmacología , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Piperazinas/química , Piperazinas/farmacología , Proteína Inhibidora de la Apoptosis Ligada a X/antagonistas & inhibidores , Animales , Línea Celular Tumoral , Cristalografía por Rayos X , Descubrimiento de Drogas , Células HEK293 , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones SCID , Peptidomiméticos , Bibliotecas de Moléculas Pequeñas , Relación Estructura-ActividadRESUMEN
The DDR1 and DDR2 receptor tyrosine kinases are activated by extracellular collagen and have been implicated in a number of human diseases including cancer. We performed a fragment-based screen against DDR1 and identified fragments that bound either at the hinge or in the back pocket associated with the DFG-out conformation of the kinase. Modeling based on crystal structures of potent kinase inhibitors facilitated the "back-to-front" design of potent DDR1/2 inhibitors that incorporated one of the DFG-out fragments. Further optimization led to low nanomolar, orally bioavailable inhibitors that were selective for DDR1 and DDR2. The inhibitors were shown to potently inhibit DDR2 activity in cells but in contrast to unselective inhibitors such as dasatinib, they did not inhibit proliferation of mutant DDR2 lung SCC cell lines.
RESUMEN
Inhibitor of apoptosis proteins (IAPs) are important regulators of apoptosis and pro-survival signaling pathways whose deregulation is often associated with tumor genesis and tumor growth. IAPs have been proposed as targets for anticancer therapy, and a number of peptidomimetic IAP antagonists have entered clinical trials. Using our fragment-based screening approach, we identified nonpeptidic fragments binding with millimolar affinities to both cellular inhibitor of apoptosis protein 1 (cIAP1) and X-linked inhibitor of apoptosis protein (XIAP). Structure-based hit optimization together with an analysis of protein-ligand electrostatic potential complementarity allowed us to significantly increase binding affinity of the starting hits. Subsequent optimization gave a potent nonalanine IAP antagonist structurally distinct from all IAP antagonists previously reported. The lead compound had activity in cell-based assays and in a mouse xenograft efficacy model and represents a highly promising start point for further optimization.
Asunto(s)
Antineoplásicos/farmacología , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , Proteínas Inhibidoras de la Apoptosis/efectos de los fármacos , Fragmentos de Péptidos/farmacología , Proteína Inhibidora de la Apoptosis Ligada a X/antagonistas & inhibidores , Animales , Antineoplásicos/síntesis química , Antineoplásicos/farmacocinética , Proliferación Celular/efectos de los fármacos , Biología Computacional , Diseño de Fármacos , Descubrimiento de Drogas , Ensayos Analíticos de Alto Rendimiento , Humanos , Ratones , Ratones Endogámicos BALB C , Modelos Moleculares , Fragmentos de Péptidos/síntesis química , Fragmentos de Péptidos/farmacocinética , Piperazinas/síntesis química , Piperazinas/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
A series of resorcylic acid macrolactams, nitrogen analogues of the naturally occurring macrolactone radicicol, have been prepared by chemical synthesis and evaluated as inhibitors of heat shock protein 90 (Hsp90), an emerging attractive target for novel cancer therapeutic agents. The synthesis involves, as key steps, ring opening of an isocoumarin intermediate, followed by a ring-closing metathesis reaction to form the macrocycle. Subsequent manipulation of the ester group into a range of amides allows access to a range of new macrolactams following deprotection of the two phenolic groups. These new resorcylic acid lactams exhibit metabolic stability greater than that of related lactone counterparts, while co-crystallization of three macrolactams with the N-terminal domain ATP site of Hsp90 confirms that they bind in a similar way to the natural product radicicol and to our previous synthetic lactone analogues. Interestingly, however, in the case of the N-benzylamide, additional binding to a hydrophobic pocket of the protein was observed. In biological assays, the new macrocyclic lactams exhibit a biological profile equivalent or superior to that of the related lactones and show the established molecular signature of Hsp90 inhibitors in human colon cancer cells.
Asunto(s)
Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Lactamas Macrocíclicas/farmacología , Proliferación Celular/efectos de los fármacos , Cristalografía por Rayos X , Células HCT116 , Humanos , Lactamas Macrocíclicas/síntesis química , Lactamas Macrocíclicas/metabolismo , Macrólidos/metabolismo , Macrólidos/farmacología , Microsomas Hepáticos/metabolismo , Modelos MolecularesRESUMEN
A series of resorcylic acid macrolactones, analogues of the natural product radicicol has been prepared by chemical synthesis, and evaluated as inhibitors of heat shock protein 90 (Hsp90), an emerging attractive target for novel cancer therapeutic agents. The synthesis involves acylation of an ortho-toluic acid dianion, esterification, followed by a ring-closing metathesis to form the macrocycle. Subsequent manipulation of the protected hydroxymethyl side chain allows access to a range of new analogues following deprotection of the two phenolic groups. Co-crystallization of one of the new macrolactones with the N-terminal domain of yeast Hsp90 confirms that it binds in a similar way to the natural product radicicol and to our previous synthetic analogues, but that the introduction of the additional hydroxymethyl substituent appears to result in an unexpected change in conformation of the macrocyclic ring. As a result of this conformational change, the compounds bound less favorably to Hsp90.
Asunto(s)
Antineoplásicos/síntesis química , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Compuestos Macrocíclicos/química , Compuestos Macrocíclicos/síntesis química , Macrólidos/síntesis química , Antineoplásicos/química , Antineoplásicos/uso terapéutico , Sitios de Unión , Línea Celular Tumoral , Cristalografía por Rayos X , Proteínas HSP90 de Choque Térmico/química , Proteínas HSP90 de Choque Térmico/metabolismo , Humanos , Macrólidos/química , Macrólidos/uso terapéutico , Conformación Molecular , Neoplasias/tratamiento farmacológico , Unión ProteicaRESUMEN
A series of benzo-macrolactones has been prepared by chemical synthesis, and evaluated as inhibitors of heat shock protein 90 (Hsp90), an emerging attractive target for novel cancer therapeutic agents. A new synthesis of these resorcylic acid macrolactone analogues of the natural product radicicol is described in which the key steps are the acylation and ring opening of a homophthalic anhydride to give an isocoumarin, followed by a ring-closing metathesis to form the macrocycle. The methodology has been extended to a novel series of macrolactones incorporating a 1,2,3-triazole ring.