RESUMEN
A series of suitable five-membered heterocyclic alternatives to thiophenes within a thienobenzoxepin class of PI3-kinase (PI3K) inhibitors was discovered. Specific thiazolobenzoxepin 8-substitution was identified that increased selectivity over PI3Kß. PI3Kß-sparing compound 27 (PI3Kß Ki,app/PI3Kα Ki,app=57) demonstrated dose-dependent knockdown of pAKT, pPRAS40 and pS6RP in vivo as well as differential effects in an in vitro proliferation cell line screen compared to pan PI3K inhibitor GDC-0941. A new structure-based hypothesis for reducing inhibition of the PI3K ß isoform while maintaining activity against α, δ and γ isoforms is presented.
Asunto(s)
Benzoxepinas/química , Inhibidores Enzimáticos/química , Inhibidores de las Quinasa Fosfoinosítidos-3 , Tiazoles/química , Benzoxepinas/síntesis química , Benzoxepinas/farmacología , Sitios de Unión , Proliferación Celular/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Humanos , Células MCF-7 , Simulación del Acoplamiento Molecular , Fosfatidilinositol 3-Quinasa/metabolismo , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/metabolismo , Estructura Terciaria de Proteína , Proteínas Proto-Oncogénicas c-akt/metabolismo , Relación Estructura-ActividadRESUMEN
Structure-activity relationships have been investigated for inhibition of DNA-dependent protein kinase (DNA-PK) and ATM kinase by a series of pyran-2-ones, pyran-4-ones, thiopyran-4-ones, and pyridin-4-ones. A wide range of IC50 values were observed for pyranones and thiopyranones substituted at the 6-position, with the 3- and 5-positions proving intolerant to substitution. Related pyran-2-ones, pyran-4-ones, and thiopyran-4-ones showed similar IC50 values against DNA-PK, whereas the pyridin-4-one system proved, in general, ineffective at inhibiting DNA-PK. Extended libraries exploring the 6-position of 2-morpholino-pyran-4-ones and 2-morpholino-thiopyrano-4-ones identified the first highly potent and selective ATM inhibitor 2-morpholin-4-yl-6-thianthren-1-yl-pyran-4-one (151C; ATM; IC50=13 nM) and revealed constrained SARs for ATM inhibition compared with DNA-PK. One of the most potent DNA-PK inhibitors identified, 2-(4-methoxyphenyl)-6-(morpholin-4-yl)pyran-4-one (16; DNA-PK; IC50=220 nM) effectively sensitized HeLa cells to the topoisomerase II inhibitor etoposide in vitro.
