RESUMEN
DNA methylation is the most studied epigenetic event. Since the methylation profile of the genome is widely modified in cancer cells, DNA methyltransferases are the target of new anticancer therapies. Nucleosidic inhibitors suffer from toxicity and chemical stability, while non-nucleosidic inhibitors lack potency. Here, we found a novel DNMT inhibitor scaffold by enzymatic screening and structure-activity relationship studies. The optimization studies led to an inhibitor containing three fragments: a gallate frame, a hydrazone linker and a benzothiazole moiety. Interestingly, the compound inhibits DNMT3A with micromolar potency (EC50 = 1.6 µM) and does not inhibit DNMT1; this DNMT3A selectivity is supported by a docking study. Finally, the compound reactivates a reporter gene in leukemia KG-1 cells.
Asunto(s)
Antineoplásicos/farmacología , ADN (Citosina-5-)-Metiltransferasas/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Ácido Gálico/farmacología , Hidrazonas/farmacología , Neoplasias/tratamiento farmacológico , Antineoplásicos/síntesis química , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , ADN (Citosina-5-)-Metiltransferasas/metabolismo , ADN Metiltransferasa 3A , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Ácido Gálico/química , Humanos , Hidrazonas/síntesis química , Hidrazonas/química , Neoplasias/metabolismo , Relación Estructura-ActividadRESUMEN
Quinoline derivative SGI-1027 (N-(4-(2-amino-6-methylpyrimidin-4-ylamino)phenyl)-4-(quinolin-4-ylamino)benzamide) was first described in 2009 as a potent inhibitor of DNA methyltransferase (DNMT) 1, 3A and 3B. Based on molecular modeling studies, performed using the crystal structure of Haemophilus haemolyticus cytosine-5 DNA methyltransferase (MHhaI C5 DNMT), which suggested that the quinoline and the aminopyridimine moieties of SGI-1027 are important for interaction with the substrates and protein, we designed and synthesized 25 derivatives. Among them, four compoundsnamely the derivatives 12, 16, 31 and 32exhibited activities comparable to that of the parent compound. Further evaluation revealed that these compounds were more potent against human DNMT3A than against human DNMT1 and induced the re-expression of a reporter gene, controlled by a methylated cytomegalovirus (CMV) promoter, in leukemia KG-1 cells. These compounds possessed cytotoxicity against leukemia KG-1 cells in the micromolar range, comparable with the cytotoxicity of the reference compound, SGI-1027. Structureactivity relationships were elucidated from the results. First, the presence of a methylene or carbonyl group to conjugate the quinoline moiety decreased the activity. Second, the size and nature of the aromatic or heterocycle subsitutents effects inhibition activity: tricyclic moieties, such as acridine, were found to decrease activity, while bicyclic substituents, such as quinoline, were well tolerated. The best combination was found to be a bicyclic substituent on one side of the compound, and a one-ring moiety on the other side. Finally, the orientation of the central amide bond was found to have little effect on the biological activity. This study provides new insights in to the structure-activity relationships of SGI-1027 and its derivative.
Asunto(s)
Aminoquinolinas/síntesis química , Aminoquinolinas/farmacología , Metilación de ADN/efectos de los fármacos , Diseño de Fármacos , Pirimidinas/síntesis química , Pirimidinas/farmacología , Quinolinas/química , Aminoquinolinas/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , ADN (Citosina-5-)-Metiltransferasa 1 , ADN (Citosina-5-)-Metiltransferasas/antagonistas & inhibidores , ADN (Citosina-5-)-Metiltransferasas/metabolismo , ADN Metiltransferasa 3A , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Pirimidinas/química , Relación Estructura-ActividadRESUMEN
DNA methyltransferases (DNMT) are promising drug targets in cancer provided that new, more specific, and chemically stable inhibitors are discovered. Among the non-nucleoside DNMT inhibitors, N-phthaloyl-l-tryptophan 1 (RG108) was first identified as inhibitor of DNMT1. Here, 1 analogues were synthesized to understand its interaction with DNMT. The indole, carboxylate, and phthalimide moieties were modified. Homologated and conformationally constrained analogues were prepared. The latter were synthesized from prolinohomotryptophan derivatives through a methodology based amino-zinc-ene-enolate cyclization. All compounds were tested for their ability to inhibit DNMT1 in vitro. Among them, constrained compounds 16-18 and NPys derivatives 10-11 were found to be at least 10-fold more potent than the reference compound. The cytotoxicity on the tumor DU145 cell line of the most potent inhibitors was correlated to their inhibitory potency. Finally, docking studies were conducted in order to understand their binding mode. This study provides insights for the design of the next-generation of DNMT inhibitors.
Asunto(s)
ADN (Citosina-5-)-Metiltransferasas/antagonistas & inhibidores , Ftalimidas/síntesis química , Triptófano/análogos & derivados , Dominio Catalítico , Línea Celular Tumoral , ADN (Citosina-5-)-Metiltransferasa 1 , ADN (Citosina-5-)-Metiltransferasas/química , Humanos , Simulación del Acoplamiento Molecular , Ácidos Ftálicos/síntesis química , Ácidos Ftálicos/química , Ácidos Ftálicos/farmacología , Ftalimidas/química , Ftalimidas/farmacología , Estereoisomerismo , Relación Estructura-Actividad , Triptófano/síntesis química , Triptófano/química , Triptófano/farmacologíaRESUMEN
Eighteen new meroterpene derivatives, dichrostachines A-R (1-18), have been isolated from the root and stem barks of Dichrostachys cinerea, and their structures determined by spectroscopic means and molecular modeling. From a biosynthetic standpoint these compounds arise from a Diels-Alder reaction between a labdane diene of the raimonol type and a flavonoid B-ring-derived quinone. The hypothesis was tested by the partial synthesis of similar compounds by simply mixing methyl communate and a synthetic flavonoid quinone. The hemisynthetic compounds were shown by NMR to have configurations different from those of the natural products, thus allowing a refinement of the biosynthesis hypothesis. Most of the compounds were assayed for their ability to inhibit the enzyme protein farnesyl transferase. The most active compounds exhibited IC50 and cytotoxicity values in the 1 microM range.
Asunto(s)
Transferasas Alquil y Aril/antagonistas & inhibidores , Fabaceae/química , Plantas Medicinales/química , Terpenos/aislamiento & purificación , Terpenos/farmacología , República Democrática del Congo , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Corteza de la Planta/química , Terpenos/químicaRESUMEN
A novel series of compounds, derived from 4-amino-phenyl piperazine, has been designed to selectively inhibit farnesyl protein transferase (FPTase) as CAAX tetrapeptide analogues. Certain of these compounds were shown to possess low nanomolar inhibitory activity both against the isolated enzyme and in cultured cells.
Asunto(s)
Transferasas Alquil y Aril/antagonistas & inhibidores , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Piperazinas/síntesis química , Piperazinas/farmacología , Transferasas Alquil y Aril/metabolismo , Inhibidores Enzimáticos/química , Humanos , Proteínas de la Membrana/química , Modelos Moleculares , Oligopéptidos/química , Piperazinas/química , Prenilación de Proteína/efectos de los fármacos , Relación Estructura-Actividad , Transferasas/antagonistas & inhibidores , Células Tumorales Cultivadas , Proteínas ras/efectos de los fármacos , Proteínas ras/metabolismoRESUMEN
Starting from a FPP analogue with nanomolar inhibitory activity against isolated FPTase, yet lacking activity in cellular assays, structural modifications were performed to enhance cellular activity by removing all acidic functionalities. Overall, these changes resulted in the transformation of a pure FPP to a mixed FPP and CAAX competitive inhibitor with nanomolar activity on isolated FPTase and micromolar inhibitory activity in the farnesylation of H-Ras in cultured DLD-1 cells.