RESUMO
Nucleoside phosphonates are widely used therapeutic agents with a broad spectrum of antiviral activity. However, only a few of them are reported to have antitumor activity. In this study, we show that a tetrahydrofuran phosphonate analogue of guanosine, (-)-2-R-dihydroxyphosphinoyl-5-(S)-(guanin-9'-ylmethyl) tetrahydrofuran (BCH-1868), previously reported as having antiviral activity, also displays antitumor activity. In vitro, BCH-1868 inhibited the proliferation of several murine and human cancer cell lines with IC50s in the microM range independently of the tissue type or the presence of multidrug resistance protein MRP/gp190. In vivo, BCH-1868 was active against a variety of human tumor xenograft models (Caki-1, HT-29, DU 145, COLO 205, and CCRF-CEM). In all tumors tested, a significant tumor growth inhibition was noted at 40-50 mg/kg (daily x 5), but no tumor regression was observed in the settings used. To better understand these results, we partially characterized, at the cellular level, the mechanism of action of this new cyclic nucleoside phosphonate and investigated its pharmacokinetic characteristics in mice. We showed that BCH-1868 exerts its antitumor activity by an inhibitory mechanism at the level of DNA polymerase a, resulting in arrest of DNA synthesis and a block of cell division at the S phase of the cell cycle. Low-circulating plasma concentration (Cmax = 87 microM; area under the curve = 1138 micromol x min/liters; after a bolus i.v. injection of 10 mg/kg) and rapid clearance of the drug (terminal half-life, t1/2 = 16 min) may contribute to the modest antitumor efficacy observed in vivo.
Assuntos
Antineoplásicos/farmacocinética , Antivirais/farmacologia , Guanina/farmacocinética , Ácidos Fosfínicos/farmacocinética , Animais , Ciclo Celular , Divisão Celular , DNA Polimerase I/antagonistas & inibidores , Relação Dose-Resposta a Droga , Guanina/análogos & derivados , Humanos , Concentração Inibidora 50 , Fígado/metabolismo , Camundongos , Camundongos Nus , Camundongos SCID , Modelos Químicos , Transplante de Neoplasias , Fatores de Tempo , Células Tumorais CultivadasRESUMO
The HCV NS5B RNA dependent RNA polymerase plays an essential role in viral replication. The discovery of a novel class of inhibitors based on an N,N-disubstituted phenylalanine scaffold and structure-activity relationships studies to improve potency are described.
Assuntos
Antivirais/síntese química , Inibidores Enzimáticos/síntese química , Hepacivirus/enzimologia , Fenilalanina/análogos & derivados , Fenilalanina/síntese química , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Proteínas não Estruturais Virais/antagonistas & inibidores , Antivirais/química , Inibidores Enzimáticos/química , Fenilalanina/química , Relação Estrutura-AtividadeRESUMO
We have identified several nucleotide phosphonates demonstrating in vitro antiproliferative activity in several human cancer cell lines with IC(50) values in the microM range. The synthesis as well as structure-activity relationship are described.
Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Furanos/síntese química , Furanos/farmacologia , Nucleotídeos/síntese química , Nucleotídeos/farmacologia , Organofosfonatos/síntese química , Organofosfonatos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Relação Estrutura-Atividade , Timidina/metabolismo , Células Tumorais CultivadasRESUMO
Herein, we describe the structure-activity relationship (SAR) of N,N-disubstituted phenylalanine series of NS5B polymerase inhibitors of hepatitis C. The NS5B polymerase inhibitory activity of the most active compound exhibited an IC(50) of 2.7 microM.
Assuntos
Inibidores Enzimáticos/química , Hepacivirus/enzimologia , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Proteínas não Estruturais Virais/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Hepacivirus/efeitos dos fármacos , Humanos , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/metabolismoRESUMO
X-ray crystal structures of two non-nucleoside analogue inhibitors bound to hepatitis C virus NS5B RNA-dependent RNA polymerase have been determined to 2.0 and 2.9 A resolution. These noncompetitive inhibitors bind to the same site on the protein, approximately 35 A from the active site. The common features of binding include a large hydrophobic region and two hydrogen bonds between both oxygen atoms of a carboxylate group on the inhibitor and two main chain amide nitrogen atoms of Ser(476) and Tyr(477) on NS5B. The inhibitor-binding site lies at the base of the thumb domain, near its interface with the C-terminal extension of NS5B. The location of this inhibitor-binding site suggests that the binding of these inhibitors interferes with a conformational change essential for the activity of the polymerase.
Assuntos
Nucleosídeos/química , Proteínas não Estruturais Virais/genética , Sítio Alostérico , Sequência de Aminoácidos , Sítios de Ligação , Ligação Competitiva , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Ligação de Hidrogênio , Concentração Inibidora 50 , Modelos Químicos , Modelos Moleculares , Dados de Sequência Molecular , Nitrogênio , Oxigênio , Ligação Proteica , Conformação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Serina/química , Tirosina/químicaRESUMO
The discovery of a novel class of HCV NS5B polymerase inhibitors, 3-arylsulfonylamino-5-phenyl-thiophene-2-carboxylic acids is described. SAR studies have yielded several potent inhibitors of HCV polymerase as well as of HCV subgenomic RNA replication in Huh-7 cells.
Assuntos
Inibidores Enzimáticos/farmacologia , Hepacivirus/enzimologia , RNA Viral/metabolismo , Sulfonamidas/farmacologia , Tiofenos/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Ácidos Carboxílicos , Carcinoma Hepatocelular/química , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/virologia , Inibidores Enzimáticos/química , Genoma Viral , Humanos , Neoplasias Hepáticas/química , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/virologia , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Replicon/efeitos dos fármacos , Relação Estrutura-Atividade , Sulfonamidas/química , Tiofenos/química , Replicação Viral/efeitos dos fármacosRESUMO
Further SAR studies on the thiophene-2-carboxylic acids are reported. These studies led to the identification of a series of tertiary amides that show inhibition of both HCV NS5B polymerase in vitro and HCV subgenomic RNA replication in Huh-7 cells. Structural insights about the bioactive conformation of this class of molecules were deduced from a combination of modeling and transferred NOE (trNOE) studies.
Assuntos
Amidas/farmacologia , Inibidores Enzimáticos/farmacologia , Hepacivirus/enzimologia , RNA Viral/metabolismo , Tiofenos/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Amidas/química , Ácidos Carboxílicos , Carcinoma Hepatocelular/química , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/virologia , Inibidores Enzimáticos/química , Genoma Viral , Humanos , Neoplasias Hepáticas/química , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/virologia , Espectroscopia de Ressonância Magnética , Conformação Molecular , Estrutura Molecular , RNA Polimerase Dependente de RNA/antagonistas & inibidores , Replicon/efeitos dos fármacos , Relação Estrutura-Atividade , Tiofenos/química , Replicação Viral/efeitos dos fármacosRESUMO
HCV NS5B RNA-dependent RNA polymerase (NS5B) is essential for viral replication and is therefore considered a target for antiviral drug development. From our ongoing screening effort in the search for new anti-HCV agents, a novel inhibitor 1 with low microM activity against the HCV NS5B polymerase was identified. SAR analysis indicated the optimal substitution pattern required for activity, for example, carboxylic acid group at 2-position of thiophene ring. We describe the steps taken to identify and solve the bioactive conformation of derivative 6 through the use of the transferred NOE method (trNOE).