RESUMEN
Herpes simplex virus infections have been described in the medical literature for centuries, yet the the drugs available nowadays for therapy are largely ineffective and low oral bioavailability plays an important role on the inefficacy of the treatments. Additionally, the details of the inhibition of Herpes Virus type 1 are still not fully understood. Studies have shown that several viruses encode one or more proteases required for the production new infectious virions. This study presents an analysis of the interactions between HSV-1 protease and benzoxazinone derivatives through a combination of structure-activity relationships, comparative modeling and molecular docking studies. The structure activity relationship results showed an important contribution of hydrophobic and polarizable groups and limitations for bulky groups in specific positions. Two Herpes Virus type 1 protease models were constructed and compared to achieve the best model which was obtained by MODELLER. Molecular docking results pointed to an important interaction between the most potent benzoxazinone derivative and Ser129, consistent with previous mechanistic data. Moreover, we also observed hydrophobic interactions that may play an important role in the stabilization of inhibitors in the active site. Finally, we performed druglikeness and drugscore studies of the most potent derivatives and the drugs currently used against Herpes virus.
Asunto(s)
Antivirales/química , Antivirales/farmacología , Benzoxazinas/química , Benzoxazinas/farmacología , Herpesvirus Humano 1/efectos de los fármacos , Herpesvirus Humano 1/enzimología , Modelos Moleculares , Péptido Hidrolasas/química , Sitios de Unión , Humanos , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Conformación Molecular , Simulación del Acoplamiento Molecular , Peso Molecular , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología , Unión Proteica , Relación Estructura-ActividadRESUMEN
In interviews on the traditional herbal medicines of Tupi-Guarany Indians at the herbal market of Asuncion and questionnaire from their users, it was clarified that various useful medicinal plants are available in Paraguay and most of them are generally used without drying. In the search for bioactive substances from those plants, a ß-glucuronidase-inhibitory diterpene called scoparic acid A (SA) was isolated from Scoparia dulcis L. together with scoparic acid B, scoparic acid C, and the aphidicolin-like tetracyclic diterpenes scopadulcic acid A (SDA) and scopadulcic acid B (SDB). HPLC analysis of diterpenes in the individual plants of Paraguayan and Asian S. dulcis revealed the presence of three chemotypes based on major component, i.e., SA type, SDB type, and SDX type containing mainly scopadiol and scopadulciol (SDC). SA and SDB were elucidated to be mainly biosynthesized in the leaves via 2-C-methyl-D-erythritol- 4-phosphate pathway, and a leaf organ culture system containing methyl jasmonate 10 µM was found to enhance the production of diterpenes by activation of Ca-signal transduction systems such as calmodulin and protein kinase C. On the other hand, SDB and SDC were found to show multifaceted pharmacological effects such as inhibitory effects on gastric acid excretion, bone resorption, replication of herpes simplex virus type 1 (HSV-1), etc. In addition, SDC was suggested to be applicable to cancer gene therapy using ganciclovir or acyclovir and the HSV-1 thymidine kinase gene called the suicide gene.
Asunto(s)
Diterpenos/aislamiento & purificación , Diterpenos/uso terapéutico , Medicina Tradicional , Scoparia/química , Abietanos/aislamiento & purificación , Abietanos/farmacología , Abietanos/uso terapéutico , Animales , Resorción Ósea/tratamiento farmacológico , Cromatografía Líquida de Alta Presión , Diterpenos/farmacología , Ácido Gástrico/metabolismo , Genes Transgénicos Suicidas , Terapia Genética , Herpesvirus Humano 1/enzimología , Herpesvirus Humano 1/fisiología , Humanos , Neoplasias/terapia , Paraguay , Fitoterapia , Ratas , Encuestas y Cuestionarios , Timidina Quinasa/genética , Replicación Viral/efectos de los fármacosRESUMEN
We describe in this paper that the synthetic chloroxoquinolinic ribonucleoside 6-chloro-1,4-dihydro-4-oxo-1-(beta-D-ribofuranosyl) quinoline-3-carboxylic acid (compound A) and its free aglycogene base (compound B) inhibit, with low cytotoxicity, the replication of herpes simplex virus type 1 and 2 (HSV-1 and HSV-2). Compound A inhibited HSV-1 replication in Vero cells with an EC(50) of 1.3 and 1.4 microM for an acyclovir (ACV)-sensitive strain and an ACV-resistant strain of this virus, respectively. Additionally, it inhibited HSV-2 replication with an EC(50) of 1.1 microM. Compound B also inhibited the ACV-sensitive and -resistant HSV-1 strains, and HSV-2 at EC(50) values of 1.7, 1.9 and 1.6 microM, respectively. Time-of-addition assays, performed with compound A, suggested that this molecule at an early time point of the HSV replication cycle. Kinetic assays demonstrated that compounds A and B inhibit the HSV DNA polymerase activity in a noncompetitive fashion, with a K(i) equal to 0.1 and 0.2 microM, respectively. Taken together, our results suggest that compounds A and B represent promising lead molecules for further anti-HSV drug design.
Asunto(s)
Aciclovir/farmacología , Antivirales/farmacología , Herpesvirus Humano 1/efectos de los fármacos , Inhibidores de la Síntesis del Ácido Nucleico , Quinolinas/farmacología , Ribonucleósidos/farmacología , Replicación Viral/efectos de los fármacos , Animales , Antivirales/química , Supervivencia Celular/efectos de los fármacos , Chlorocebus aethiops , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Herpesvirus Humano 1/enzimología , Herpesvirus Humano 1/fisiología , Quinolinas/química , Ribonucleósidos/química , Células VeroRESUMEN
Early passages of cultured cells derived from four spontaneous Balb/c murine adenocarcinomas were used to explore the feasibility of a nonviral HSVtk-based suicide gene therapy system. After lipofection with pCMVtk, the transiently HSVtk expressing P07 (lung), M3, M05, and M38 (mammary gland) cells were, respectively, about 130-, 30-, 120-, and 170-fold more sensitive to ganciclovir (GCV) in vitro than their respective controls. Eighty percent of Balb/c mice subcutaneously inoculated with ex vivo pCMVtk-lipofected P07 cells, followed by intraperitoneal GCV injection for 7 days, displayed a complete inhibition of tumor growth for over 70 days. Control animals started to display tumors 13 days after inoculation. We present evidence showing that early passages of cultured tumor cells can efficiently express lipofected genes and that they are sensitive to the lipoplex-mediated HSVtk/GCV system.
Asunto(s)
Adenocarcinoma/terapia , Antivirales/uso terapéutico , Ganciclovir/uso terapéutico , Herpesvirus Humano 1/genética , Neoplasias Pulmonares/terapia , Neoplasias Mamarias Experimentales/terapia , Simplexvirus/enzimología , Timidina Quinasa/genética , Adenocarcinoma/patología , Animales , Efecto Espectador , Herpesvirus Humano 1/enzimología , Humanos , Técnicas In Vitro , Liposomas , Neoplasias Pulmonares/patología , Masculino , Neoplasias Mamarias Experimentales/patología , Ratones , Ratones Endogámicos BALB C , Tasa de Supervivencia , Timidina Quinasa/metabolismo , Transducción Genética , Células Tumorales Cultivadas , beta-Galactosidasa/metabolismoRESUMEN
A quantitative structure-activity relationship study of N2-(substituted)-phenylguanines (PHG) as inhibitors of herpes simplex virus thymidine kinase (HSV TK) was performed. The activity of a set of PHG derivatives were analyzed against the thymidine kinase of herpes simplex virus types 1 (HSV1 TK) and 2 (HSV2 TK). Classic and calculated physicochemical parameters were included in the analysis. The results showed that there is an important difference in the activity of the meta substituted PHG derivatives against HSV1 TK and HSV2 TK. The activity of the meta derivatives against HSV2 TK is influenced by a steric effect, which is not observed against HSV1 TK. The superposition of the three-dimensional structures of the active sites of HSV1 TK (crystal structure) and HSV2 TK (homology model) revealed that the amino acid Ile97 is located near the meta position in the HSV1 TK active site, whereas the amino acid Leu97 is located near the meta position in the HSV2 TK active site. This single difference in the active sites of both enzymes can explain the source of the steric effect and serves as an indication that our previously proposed binding mode for the PHG derivatives is plausible. However, another observed mutation in the active site region, Ala168 by Ser168, suggests that an alternative binding mode, similar to that of ganciclovir, could be possible.
Asunto(s)
Gráficos por Computador , Inhibidores Enzimáticos/química , Guanina/análogos & derivados , Guanina/química , Simplexvirus/enzimología , Timidina Quinasa/antagonistas & inhibidores , Secuencia de Aminoácidos , Simulación por Computador , Inhibidores Enzimáticos/farmacología , Guanina/farmacología , Herpesvirus Humano 1/enzimología , Herpesvirus Humano 2/enzimología , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Molecular , Relación Estructura-Actividad Cuantitativa , Alineación de Secuencia , Estadística como Asunto , Timidina Quinasa/química , Timidina Quinasa/metabolismoRESUMEN
The probable binding mode of the herpes simplex virus thymidine kinase (HSV1 TK) N2-[substituted]-phenylguanine inhibitors is proposed. A computational experiment was designed to check some qualitative binding parameters and to calculate the interaction binding energies of alternative binding modes of N2-phenylguanines. The known binding modes of the HSV1 TK natural substrate deoxythymidine and one of its competitive inhibitors ganciclovir were used as templates. Both the qualitative and quantitative parts of the computational experiment indicated that the N2-phenylguanine derivatives bind to the HSV1 TK active site in the deoxythymidine-like binding mode. An experimental observation that N2-phenylguanosine derivatives are not phosphorylated during the interaction with the HSV1 TK gives support to the proposed binding mode.