Construcción QSAR de redes complejas de compuestos de interés en Química Farmacéutica, Microbiología y Parasitología

El diseño para la búsqueda y desarrollo de fármacos eficaces para el tratamiento de estas enfermedades, que supriman la eliminación o la degeneración celular respectivamente, es una de las líneas de investigación más importantes dentro de la química farmacéutica. En esto entra el diseño de fármacos; el diseño de fármacos está dedicado al desarrollo de modelos matemáticos para predecir propiedades de interés para una gran variedad de sistemas químicos incluyendo moléculas de bajo peso molecular, polímeros, biopolímeros, sistemas heterogéneos, formulaciones farmacéuticas, conglomerados de moléculas e iones, materiales, nano-estructuras y otros. Este tipo de predicciones no pretenden sustituir las técnicas experimentales sino complementar las mismas ayudando a obtener nuevas moléculas activas con mayor probabilidad de éxito, con la ventaja que ello supone en términos de ahorro de tiempo, recursos materiales, y muy importante: el refinamiento y reducción en el uso de animales de laboratorio. Esta metodología se basa en el uso de cálculos por ordenador y en las nuevas tecnologías de la informática. Las cuales pueden ser usadas: Para moléculas pequeñas: a) Estudios de relación cuantitativa estructura molecular-actividad farmacológica (QSAR) y de estructura molecular propiedades toxicológicas y eco-toxicológicas incluyendo mutagenicidad e carcinogénesis (QSTR). b) Predicción de propiedades químicas y fisicoquímicas de moléculas. Estudios de relación estructura molecular y propiedades de absorción, distribución, metabolismo y eliminación (ADME). c) Predicción de mecanismos de acción biológica de moléculas y evaluación in sílico de alta eficacia para grandes bases de datos (virtual HTS). Para macromoléculas: a) Estudios de interacción fármaco-receptor (neuronas). b) Bioinformática aplicada a estudios de relación secuencia-función y propiedades estructurales de ácidos nucleicos y proteínas. c) Búsqueda de nuevas dianas terapéuticas y “sitio activo” a partir de datos de Genómica, Proteómica. d) Búsqueda de biomarcadores para diagnóstico de enfermedades o como indicadores de contaminaciones. e) Predicción de propiedades fisicoquímicas de polímeros sintéticos, biopolímeros, materiales y nano-estructuras. f) Predicción, diseño, y optimización de enzimas mutadas para procesos biotecnológicos

Current and future chemotherapy for Chagas disease

Luís Gaspar is thankful to FCT for funding (scholarship reference: SFRH/BD/81604/2011). The research leading to these results has received funding from the European Community’s Seventh Framework Programme under grant agreement No.602773 (Project KINDRED) and No. 603240 (Project NMTrypI).American trypanosomiasis, commonly called Chagas disease, is one of the most neglected illnesses in the world and remains one of the most prevalent chronic infectious diseases of Latin America with thousands of new cases every year. The only treatments available have been introduced five decades ago. They have serious, undesirable side effects and disputed benefits in the chronic stage of the disease – a characteristic and debilitating cardiomyopathy and/or megavisceras. Several laboratories have therefore focused their efforts in finding better drugs. Although recent years have brought new clinical trials, these are few and lack diversity in terms of drug mechanism of action, thus resulting in a weak drug discovery pipeline. This fragility has been recently exposed by the failure of two candidates, posaconazole and E1224, to sterilely cure patients in phase 2 clinical trials. Such setbacks highlight the need for continuous, novel and high quality drug discovery and development efforts to discover better and safer treatments. In this article we will review past and current findings on drug discovery for Trypanosoma cruzi made by academic research groups, industry and other research organizations over the last half century. We will also analyze the current research landscape that is now better placed than ever to deliver alternative treatments for Chagas disease in the near futurePostprintPeer reviewe

In vitro metabolism of tetrazole aminoquinolines and derivatives of metergoline and fusidic acid

Includes bibliographical references.Drug metabolism is recognised as a key component of the drug discovery and development process. It exerts an influence on the action, duration of action and toxicity of a drug in vivo. The integration of drug metabolism studies is therefore crucial to compound progression through the various stages of the development process. This work details the in vitro metabolism work conducted during the early development of aminoquinoline tetrazoles, and derivatives of metergoline and fusidic acid as potential antiplasmodial and/or antimycobacterial agents

NONCOVALENT FLUOROUS INTERACTIONS: NEW APPROACHES FOR DRUG DISCOVERY AND DRUG DELIVERY

The unique chemical properties of fluorine atom (high electronegativity, high ionization potential, low polarizability and low van der Waals interactions) modify the chemical properties of organic compounds as well as their reactivity when hydrogen atoms are replaced by fluorines. Actually, fluorocarbons show low polarity, which is responsible for the high hydrophobicity of these molecules. Additionally, the low polarizability of fluorines leads to weaker van der Waals interactions, which makes fluorocarbons lipophobic. Therefore, fluorinated compounds show an amphiphilic character that leads to the formation of the fluorous phase, which is separated to both aqueous and organic layers. The aim of my project was applying the strong and noncovalent fluorous interactions to drug discovery and drug delivery. The first part of my thesis is focused on the development of a new strategy for target identification able to overcome the several limitations associated to classic chemical proteomics techniques. Indeed, traditional chemical proteomics methodology uses agarose beads covalently bound to streptavidin as stationary phase for affinity purification. This resin is able to retain biotin-tagged proteins as well as sticky components abundant in the lysate. These contaminants might be aspecifically eluted with the biological targets, complicating the mass analysis and therefore the target identification. In order to increase the selectivity of the proteomics approach, we designed an innovative fluorous proteomics methodology using the strong fluorous-fluorous interactions as recognition system for affinity purification. Indeed, perfluorinated stationary phase can anchor only fluorinated species, avoiding aspecific binding. To test the fluorous proteomics approach, papain was considered as biological target. Fluorinated inhibitors of papain with different fluorinated-chain length were synthesized. The number of fluorine atom of the inhibitor is crucial for the interaction with the fluorinated stationary phase in the purification step. Actually, only papain inhibitors with a long fluorous alkyl chain are able to bind the fluorinated resin and therefore immobilize papain. In contrast, inhibitors with a short fluorous alkyl chain cannot bind the fluorinated stationary phase by means of fluorous-fluorous interactions. Consequently, papain cannot be anchored to the resin. The second part of my thesis is focused on the application of fluorous interactions for drug delivery. This project was carried out in the School of Pharmacy, University of Wisconsin-Madison (Madison, WI, U.S.A.) under the supervision of Professor Sandro Mecozzi. The aim was designing and synthesizing semifluorinated dibranched polymers. The synthesis of fluorinated molecules is a challenge, due to their poor reactivity and low solubility in commonly-used organic solvents. To increase the final yield, each step of the synthesis of the semifluorinated dibranched polymers was optimized. The dibranched fluorinated polymers will be used to prepare oil-in-water nanoemulsions for controlled drug release of paclitaxel. We reasoned that semifluorinated polymers with different chemical structures might lead to nanoemulsions with different stability and drug release profile. Small diameter of the nanoemulsion droplets and long half-lives are desired to maximize the tumoritropic accumulation of these nanosystems by EPR effect before drug release. This allows the release of the drug within the tumor instead of in the bloodstream, avoiding side effects due to the interaction of the drug with off targets and consequently reducing the systemic toxicity

Synthesis and biological evaluation of novel anti-tumour (E)-styrylsulfonyl methylpyridines

ON01910.Na (Rigosertib, Estybon®), a styryl benzylsulfone, is a Phase III stage anti-cancer agent. This non-ATP competitive kinase inhibitor has multi-targeted activity, promoting mitotic arrest and apoptosis. Extensive Phase I/II studies with ON01910.Na, conducted in patients with solid tumours and haematological cancers demonstrate excellent efficacy. However, issues remain affecting its development. These include incomplete understanding of anti-tumour mechanisms, low oral bioavailability and unpredictable pharmacokinetics. In an attempt to improve drug-likeness and ADME properties of ON01910.Na analogues, a novel series of (E)-styrylsulfonyl methylpyridine derivatives was designed and synthesised. The SAR of this novel series is discussed. The lead compounds TL-68, TL-77, and AH-123 are highly potent mitotic inhibitors. Their selective cytotoxicity to cancer cells was identified in the screening cascade. Impressively, TL-77 possesses excellent pharmaceutical properties, with improved oral bioavailability when compared to ON01910.Na. The detailed cellular mechanisms of TL-77 were further investigated in comparison with ON01910.Na. TL-77 exhibits potent anti-proliferative activity against a wide range of human tumour cell lines, and demonstrated > 2 fold greater potency in cancer cell lines over normal cells.. Cell cycle analyses reveal that TL-77 evokes profound G2/M cell cycle arrest at ≥ 6 h in cancer cells, followed by the onset of apoptosis. In cell-free conditions, TL-77 as well as ON01910.Na potently inhibits tubulin polymerization. Mitotically arrested cells display multipolar spindles and misalignment of chromosomes, indicating TL-77 interfere mitotic spindle assembly in cancer cells. These effects are accompanied by induction of DNA damage, inhibition of Cdc25c (Ser198) phosphorylation [indicative polo-like kinase 1 (Plk1) inhibition], and downstream inhibition of cyclin B1. However, kinase assays failed to confirm the inhibition of Plk1. Non-significant effects on PI3K/AKT signal transduction are observed after TL-77 treatment. Analysis of apoptotic signalling pathways reveals that TL-77 down-regulates expression of B-cell lymphoma 2 (Bcl-2) family proteins [Bid (BH3 interacting-domain death agonist), Bcl-xl (B-cell lymphoma-extra large) and Mcl-1 (induced myeloid leukaemia cell differentiation protein)] and stimulates caspase activation. These effects are comparable to those elicited by ON01910.Na. Unlike ON01910.Na, however, TL-77 causes preferential toxicity in cancer cells when compared to normal cells and mediates rapid mitotic inhibitory effects. In summary, selective in vitro anti-tumour activity and multi-faceted mechanisms of action of a novel molecule TL-77 have been identified, presenting a strong rationale for further development of (E)-styrylsulfonyl methylpyridine derivatives as therapeutic agents for cancer

Synthesis and biological evaluation of novel anti-tumour (E)-styrylsulfonyl methylpyridines

ON01910.Na (Rigosertib, Estybon®), a styryl benzylsulfone, is a Phase III stage anti-cancer agent. This non-ATP competitive kinase inhibitor has multi-targeted activity, promoting mitotic arrest and apoptosis. Extensive Phase I/II studies with ON01910.Na, conducted in patients with solid tumours and haematological cancers demonstrate excellent efficacy. However, issues remain affecting its development. These include incomplete understanding of anti-tumour mechanisms, low oral bioavailability and unpredictable pharmacokinetics. In an attempt to improve drug-likeness and ADME properties of ON01910.Na analogues, a novel series of (E)-styrylsulfonyl methylpyridine derivatives was designed and synthesised. The SAR of this novel series is discussed. The lead compounds TL-68, TL-77, and AH-123 are highly potent mitotic inhibitors. Their selective cytotoxicity to cancer cells was identified in the screening cascade. Impressively, TL-77 possesses excellent pharmaceutical properties, with improved oral bioavailability when compared to ON01910.Na. The detailed cellular mechanisms of TL-77 were further investigated in comparison with ON01910.Na. TL-77 exhibits potent anti-proliferative activity against a wide range of human tumour cell lines, and demonstrated > 2 fold greater potency in cancer cell lines over normal cells.. Cell cycle analyses reveal that TL-77 evokes profound G2/M cell cycle arrest at ≥ 6 h in cancer cells, followed by the onset of apoptosis. In cell-free conditions, TL-77 as well as ON01910.Na potently inhibits tubulin polymerization. Mitotically arrested cells display multipolar spindles and misalignment of chromosomes, indicating TL-77 interfere mitotic spindle assembly in cancer cells. These effects are accompanied by induction of DNA damage, inhibition of Cdc25c (Ser198) phosphorylation [indicative polo-like kinase 1 (Plk1) inhibition], and downstream inhibition of cyclin B1. However, kinase assays failed to confirm the inhibition of Plk1. Non-significant effects on PI3K/AKT signal transduction are observed after TL-77 treatment. Analysis of apoptotic signalling pathways reveals that TL-77 down-regulates expression of B-cell lymphoma 2 (Bcl-2) family proteins [Bid (BH3 interacting-domain death agonist), Bcl-xl (B-cell lymphoma-extra large) and Mcl-1 (induced myeloid leukaemia cell differentiation protein)] and stimulates caspase activation. These effects are comparable to those elicited by ON01910.Na. Unlike ON01910.Na, however, TL-77 causes preferential toxicity in cancer cells when compared to normal cells and mediates rapid mitotic inhibitory effects. In summary, selective in vitro anti-tumour activity and multi-faceted mechanisms of action of a novel molecule TL-77 have been identified, presenting a strong rationale for further development of (E)-styrylsulfonyl methylpyridine derivatives as therapeutic agents for cancer