Choline kinase active site provides features for designing versatile inhibitors.

Choline kinase (CK) is a homodimeric enzyme that catalyses the transfer of the ATP γ-phosphate to choline, generating phosphocholine and ADP in the presence of magnesium. Several isoforms of CK are present in humans but only the HsCKα has been associated with cancer and validated as a drug target to treat this disease. As a consequence a large number of compounds based on Hemicholinium (HC-3) have been described. Two compounds, previously reported to inhibit the human enzyme, have recently been shown to inhibit P. falciparum CK (PfCK) and therefore their potential applications might be anticipated to other pathogens. Herein, using molecular dynamic simulations, we have firstly observed that the ATP and the choline binding site of different CK in pathogens and human are conserved, suggesting that previous compounds inhibiting the human enzyme may also interact with CKs from different pathogens. We have substantiated such observation with experimental assays showing that HsCKα1, PfCK and CpCK bind to two compounds with distinct structural features in the low µM range. Collectively, these results uncover similarities among the choline kinase binding site from different pathogenic species and the human enzyme, highlighting the feasibility of designing novel inhibitors based on the choline binding pocket.

Melatonin synthetic analogs as nitric oxide synthase inhibitors.

Nitric oxide (NO), which is produced by oxidation of L-arginine to L-citrulline in a process catalyzed by different isoforms of nitric oxide synthase (NOS), exhibits diverse roles in several physiological processes, including neurotransmission, blood pressure regulation and immunological defense mechanisms. On the other hand, an overproduction of NO is related with several disorders as Alzheimer's disease, Huntington's disease and the amyotrophic lateral sclerosis. Taking melatonin as a model, our research group has designed and synthesized several families of compounds that act as NOS inhibitors, and their effects on the excitability of N-methyl-D-aspartate (NMDA)-dependent neurons in rat striatum, and on the activity on both nNOS and iNOS were evaluated. Structural comparison between the three most representative families of compounds (kynurenines, kynurenamines and 4,5-dihydro-1H-pyrazole derivatives) allows the establishment of structure-activity relationships for the inhibition of nNOS, and a pharmacophore model that fulfills all of the observed SARs were developed. This model could serve as a template for the design of other potential nNOS inhibitors. The last family of compounds, pyrrole derivatives, shows moderate in vitro NOS inhibition, but some of these compounds show good iNOS/nNOS selectivity. Two of these compounds, 5-(2-aminophenyl)-1H-pyrrole-2-carboxylic acid methylamide and cyclopentylamide, have been tested as regulators of the in vivo nNOS and iNOS activity. Both compounds prevented the increment of the inducible NOS activity in both cytosol (iNOS) and mitochondria (i-mtNOS) observed in a MPTP model of Parkinson's disease.

Derivados de 4, 5-DIHIDRO-1H-PIRAZOL como inhibidores selectivos de nNOS: Síntesis y relaciones estructura-actividad / 4, 5-DIHYDRO-1H-PYRAZOLE as nNOS selective inhibitors: Synthesis and structure-activity relationship

INTRODUCCIÓN: La oxido nítrico sintasa (NOS) es la enzima que cataliza la biosíntesis de óxido nítrico (NO) a partir de L-arginina. 1 Hasta el momento, se han descubierto cuatro isoformas:2 nNOS, iNOS, eNOS y mtNOS. El NO es un biomensajero relacionado con importantes funciones fisiológicas. 3Sin embargo, se ha demostrado que una sobreproducción de NO por la nNOS está implicada en procesos neurodegenerativos. 4 Este hecho justifica la necesidad terapéutica de encontrar inhibidores selectivos de la nNOS que permitan luchar contra enfermedades tales como Alzheimer, Parkinson, esclerosis lateral amiotrófica y corea de Huntington. Nuestro grupo de investigación ha sintetizado y evaluado una serie de derivados kinurenínicos 5 1 y kinurenamínicos 6 2 como agentes neuroprotectores que resultaron desprovistos de actividad inhibitoria frente a la enzima kinurenina-3-hidroxilasa (KYN3OH), lo que demuestra que su actividad neuroprotectora se debe a la inhibición de la nNOS. OBJETIVO: Basándonos en estos antecedentes, hemos sintetizado y realizado la evaluación biológica in vitrofrente a las isoformas nNOS e iNOS de una serie de derivados de 4,5-dihidro-1H-pirazol con estructura general 3, con objeto de encontrar inhibidores selectivos de alguna de estas isoformas. METODOLOGÍA: Tomando como referencia los derivados kinurenínicos y kinurenamínicos, hemos sintetizado los análogos rígidos con un resto de 4,5-dihidro-1H-pirazol. Además de la restricción conformacional, se han llevado a cabo otras modificaciones, como la introducción de distintos sustituyentes en el anillo aromático y la modificación del grupo acilo en el anillo de pirazolina(AU)

CONCLUSIÓN /DISCUSIÓN: Todos los compuestos ensayados inhiben nNOS. La inhibición de iNOS es ínfima en la mayoría de los casos, por lo que se pueden considerar selectivos, y no hay inhibición de KYN3OH. Por consiguiente, el potencial neuroprotector de estos derivados se debe únicamente a la inhibición de nNOS(AU)

INTRODUCTION: Nitric Oxide Synthase (NOS) is the enzyme which catalyses the biosynthesis of Nitric Oxide (NO)from L-arginine 1. Four NOS isoforms have been described: 2 nNOS, iNOS, eNOS and mtNOS. NO is a biological messenger involved in several physiologic processes. 3 However, an over production of NO by nNOS produces neurotoxicity which has been associated with various neurological disorders 4.Therefore, it is necessary to found nNOS inhibitors to fight pathologies such as Alzheimer’s disease, Parkinson, amyotrophic lateral sclerosis and Huntington’s disease. In previous papers, our research group have described the synthesis of a series of kynurenine 5 1 and kynurenamine 6 2 derivatives as neuroprotective agents which are not active versus kynurenine-3-hydroxylase (KYN3OH). This fact demonstrates that their neuroprotective activity is only due to then NOS inhibition. 2 3 OBJECTIVE: Basing on these precedents, we have developed and evaluated in vivo, versus nNOS and iNOS, a series of 4,5-dihydro-1H-pyrazole derivatives with general structure 3 in order to find new selective compounds. METHODOLOGY: Taking kynurenine and kynurenamine derivatives as reference, we have synthesized rigid analogous with a ring of 4,5-dihydro-1H-pyrazole . Besides the conformacional restriction, other modification shave been carried out, as the introduction of different substituents in the aromatic ring and the modification of the acyl group in the pyrazoline ring . CONCLUSION /DISCUSION: All compounds inhibit nNOS. In most of cases, the inhibition of iNOS is negligible. Thus, they can be considered selective. On the other hand, there is no KYN3OH inhibition. Consequently, the neuroprotective potential of these derivatives is due only to the inhibition of nNOS(AU)

(Q)SAR studies to design new human choline kinase inhibitors as antiproliferative drugs.

Most of the signal transduction pathways are mediated by protein kinases regulating every aspect of cell function. Mutations which deregulate their expression or their function or both result in cancers. Therefore, protein kinase inhibitors have become the focus of development of new therapies for cancer. A comprehensive review of Choline kinase (ChoK) was published by us in 2003. Since then, molecular information of ChoK inhibitors has been accumulated. In this review, we intend to summarize the new lines of evidence that will include the design of the most active antiproliferative agents so far described against ChoK. Studies have been aimed at the establishment of structure-activity relationships and the structural parameters that define ChoK inhibitory and antiproliferative activities of a set of twenty-five acyclic biscationic pyridophane and forty acyclic biscationic quinolinephane compounds. The corresponding QSAR equation was obtained for the whole set of bisquinolinium compounds for the antiproliferative activity, taking into consideration the electronic parameter sigma(R) of R(4), the molar refractivity (MR) of R(8), and the lipophilic parameters clog P and pi(linker). The most potent antiproliferative agent shows an IC(50) = 0.45 microM, predicted by the QSAR equation, whilst its experimental value is IC(50) = 0.20 microM. Finally, toxicity assays were performed for the most promising compounds because of their interesting antiproliferative activities [IC(50 HT-29) = 0.70, 0.80, 1.50 and 1.90 microM] and low toxicity [LD(50) = 16.7, 12.5, > 25 and > 20 mg/kg of mouse]. These biological activities justify further analysis for antitumoral assays under in vivo conditions.

Structural elucidation of a new delta2-pyrazoline derivatives using 1H and 13C NMR spectroscopy.

This paper describes the unequivocal structural elucidation of a new kind of Delta2-pyrazoline derivatives carried out by means of monodimensional 1H and 13C NMR spectroscopies, bidimensional ones such as HMBC and HMQC experiments, and NOEDIFF effects. Conformational analysis of this molecule agrees very well with the experimentally NOEDIFF effects found.

Embolización arterial uterina. Resultados a corto plazo / Uterine artery embolisation short term results

La embolización de las arterias uterinas es un tratamiento alternativo a la histerectomía en pacientes con miomas sintomáticos que consiste en la oclusión de dichas arterias bajo control radioscópico inyectando partículas de alcohol polivinílico gelificado. En este estudio presentamos los resultados obtenidos en el Hospital Universitario Virgen de las Nieves de Granada durante los años 2001 y 2002, en cuanto a mejoría sintomática, disminución del tamaño uterino, satisfacción de las pacientes y fertilidad posterior (AU)

LUMO energy of model compounds of bispyridinium compounds as an index for the inhibition of choline kinase.

Eleven derivatives of 1,1'-[1,2-ethylenebis(benzene-1,4-diylmethylene)]bis(4-pyridinium) dibromides bearing various groups at C-4 of the pyridinium moiety were synthesized and examined for their inhibition of choline kinase (ChoK) and antiproliferative activities. The C-4 substituents include electron-releasing, neutral or electron-withdrawing groups. A one-parameter regression equation has been derived which satisfactorily describes the ex vivo inhibitory potency of ChoK of the title compounds. The electronic effect plays a critical function in the ex vivo inhibition of ChoK although the role of electrostatic interactions could be altered due to a solvation process of both ChoK and ligands.

Los nuevos retos de la industria farmacéutica / New challenges of the pharmaceutical industry

En este trabajo se analizan los distintos retos de la industria farmacéutica moderna. La elevada competitividad del sector farmacéutico y las nuevas regulaciones dictadas por los diferentes gobiernos u organismos encargados de velar por la salud pública han generado la necesidad de idear nuevas vías en el descubrimiento de nuevos medicamentos. Por una parte, el diseño racional de fármacos ha adquirido un enorme protagonismo y, por otra, el desarrollo de la robótica han potenciado el desarrollo de la química combinatoria y del tamizado de alta producción. La futura industria farmacéutica debe ser más dinámica e innovadora. Uno de sus fenómenos observados ha sido el elevado número de fusiones de empresas farmacéuticas, ante la necesidad de reducir los costes de los productos (AU)

A New Systematization of the Conformational Behavior of Seven-Membered Rings. Isoclinal Anomeric and Related Orientations(1).

The chair and twist-chair conformations of seven-membered rings are classified as a function of the signs of their endocyclic torsion angles. The conformational analysis (MM3) of the methoxy- and methyloxepanes 1-6 used as patterns allows the study and classification of the different types of hydrogen orientation in the seven-membered saturated heterocycles. General principles are established, allowing the prediction of the stability of the different twist-chair conformations as a function of the substituent type, its position in the ring, and the type of hydrogen atom that has been substituted. These results are extended to the 1,4-dioxepane derivatives 7-13 and are compared with experimental data.

Anticancer pyrimidine acyclonucleosides.

Several acyclonucleosides have been synthesized. Series 8 could liberate 5-FU and acrolein selectively in the tumour tissue whilst 9 only discharge 5-FU. The conformational analysis of 8 and 9 has been carried out by means of Molecular Mechanics, using the MM2 force field. It was observed that the open chain linked to the N-1 of the 5-FU moiety mimics the conformational structure of the sugar of desoxyuridine. Biological assays have been carried out in vitro on tumour growth in Ehrlich ascitic cells with the consequent decrease of 35% in the cellular mitosis. IC50 showed values between 3-45 microM for series 8 whilst series 9 were less active than 5-FU. Compared with that of 5-FU the acute and chronic toxicity is considerably decreased.