RESUMEN
A series of inhibitors of Autotaxin (ATX) have been developed from a high throughput screening hit, 1a, which shows an alternative binding mode to known catalytic site inhibitors. Selectivity over the hERG channel and microsomal clearance were dependent on the lipophilicity of the compounds, and this was optimised by reduction of clogD whilst maintaining high affinity ATX inhibition. Compound 15a shows good oral exposure, and concentration dependent inhibition of formation of LPA in vivo, as shown in pharmacokinetic-pharmacodynamic (PK/PD) experiments.
Asunto(s)
Amidas/farmacología , Cinamatos/farmacología , Desarrollo de Medicamentos , Inhibidores Enzimáticos/farmacología , Hidrolasas Diéster Fosfóricas/metabolismo , Tetrazoles/farmacología , Amidas/síntesis química , Amidas/química , Animales , Cinamatos/síntesis química , Cinamatos/química , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Ratones , Modelos Moleculares , Estructura Molecular , Ratas , Relación Estructura-Actividad , Tetrazoles/síntesis química , Tetrazoles/químicaRESUMEN
Tyrosyl DNA phosphodiesterase 2 (TDP2) facilitates the repair of topoisomerase II (TOP2)-linked DNA double-strand breaks and, as a consequence, is required for cellular resistance to TOP2 "poisons". Recently, a deazaflavin series of compounds were identified as potent inhibitors of TDP2, in vitro. Here, however, we show that while some deazaflavins can induce cellular sensitivity to the TOP2 poison etoposide, they do so independently of TDP2 status. Consistent with this, both the cellular level of etoposide-induced TOP2 cleavage complexes and the intracellular concentration of etoposide was increased by incubation with deazaflavin, suggesting an impact of these compounds on etoposide uptake/efflux. In addition, deazaflavin failed to increase the level of TOP2 cleavage complexes or sensitivity induced by m-AMSA, which is a different class of TOP2 poison to which TDP2-defective cells are also sensitive. In conclusion, while deazaflavins are potent inhibitors of TDP2 in vitro, their limited cell permeability and likely interference with etoposide influx/efflux limits their utility in cells.
Asunto(s)
Compuestos Aza/química , Proteínas de Unión al ADN/antagonistas & inhibidores , Etopósido/farmacocinética , Flavinas/farmacología , Inhibidores de Topoisomerasa II/farmacocinética , Animales , Transporte Biológico , Línea Celular , Pollos , Flavinas/química , Flavinas/farmacocinética , Humanos , Hidrolasas Diéster Fosfóricas , Bibliotecas de Moléculas Pequeñas/farmacologíaRESUMEN
A series of inhibitors of Autotaxin (ATX) has been developed using the binding mode of known inhibitor, PF-8380, as a template. Replacement of the benzoxazolone with a triazole zinc-binding motif reduced crystallinity and improved solubility relative to PF-8380. Modification of the linker region removed hERG activity and led to compound 12 - a selective, high affinity, orally-bioavailable inhibitor of ATX. Compound 12 concentration-dependently inhibits autotaxin and formation of LPA in vivo, as shown in pharmacokinetic-pharmacodynamic experiments.
Asunto(s)
Diseño de Fármacos , Inhibidores de Fosfodiesterasa/farmacología , Hidrolasas Diéster Fosfóricas/metabolismo , Triazoles/farmacología , Administración Oral , Animales , Benzoxazoles/farmacología , Estabilidad de Medicamentos , Humanos , Masculino , Microsomas/metabolismo , Inhibidores de Fosfodiesterasa/administración & dosificación , Inhibidores de Fosfodiesterasa/síntesis química , Inhibidores de Fosfodiesterasa/farmacocinética , Piperazinas/farmacología , Ratas Sprague-Dawley , Solubilidad , Triazoles/administración & dosificación , Triazoles/síntesis química , Triazoles/farmacocinéticaRESUMEN
MASTL (microtubule-associated serine/threonine kinase-like), more commonly known as Greatwall (GWL), has been proposed as a novel cancer therapy target. GWL plays a crucial role in mitotic progression, via its known substrates ENSA/ARPP19, which when phosphorylated inactivate PP2A/B55 phosphatase. When over-expressed in breast cancer, GWL induces oncogenic properties such as transformation and invasiveness. Conversely, down-regulation of GWL selectively sensitises tumour cells to chemotherapy. Here we describe the first structure of the GWL minimal kinase domain and development of a small-molecule inhibitor GKI-1 (Greatwall Kinase Inhibitor-1). In vitro, GKI-1 inhibits full-length human GWL, and shows cellular efficacy. Treatment of HeLa cells with GKI-1 reduces ENSA/ARPP19 phosphorylation levels, such that they are comparable to those obtained by siRNA depletion of GWL; resulting in a decrease in mitotic events, mitotic arrest/cell death and cytokinesis failure. Furthermore, GKI-1 will be a useful starting point for the development of more potent and selective GWL inhibitors.
Asunto(s)
Proteínas Asociadas a Microtúbulos/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/síntesis química , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Cristalización , Células HeLa , Humanos , Proteínas Asociadas a Microtúbulos/química , Fosforilación , Dominios Proteicos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Serina-Treonina Quinasas/química , Relación Estructura-ActividadRESUMEN
Using a parallel synthesis approach to target a non-conserved region of the PI3K catalytic domain a pan-PI3K inhibitor 1 was elaborated to provide alpha, delta and gamma isoform selective Class I PI3K inhibitors 21, 24, 26 and 27. The compounds had good cellular activity and were selective against protein kinases and other members of the PI3K superfamily including mTOR and DNA-PK.