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1.
Malar J ; 22(1): 210, 2023 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-37454145

RESUMEN

BACKGROUND: Plasmodium falciparum cysteine-rich protective antigen (PfCyRPA) is an invasion complex protein essential for erythrocyte invasion. In contrast to several previously clinically tested merozoite vaccine candidate antigens, PfCyRPA is not polymorphic, making it a promising candidate antigen for blood stage vaccine development. METHODS: Mice and rabbits were immunized with vaccine formulations of recombinantly expressed PfCyRPA adjuvanted either with the glucopyranosyl lipid A (GLA) containing adjuvants GLA-LSQ, GLA-SE, GLA-Alum or with Nanoalum. ELISA and indirect immunofluorescence assays (IFA) were used to analyse elicited IgG titers and the P. falciparum growth inhibitory activity was determined with a standardized in vitro [3H]-hypoxanthine incorporation assay. RESULTS: In the mouse experiments, the GLA adjuvanted formulations were superior to the Nanoalum formulation with respect to antibody titer development, IFA sero-conversion rates and in vitro parasite growth-inhibitory activity. In rabbits, the highest titers of parasite growth inhibitory antibodies were obtained with the GLA-SE formulation. Comparable mean ELISA IgG endpoint titers were reached in rabbits after three immunizations with GLA-SE adjuvanted PfCyRPA doses of 5, 25 and 100 µg, but with 100 µg of antigen, only two immunizations were required to reach this titer. CONCLUSION: PfCyRPA formulated with the human-compatible adjuvant GLA-SE represents an attractive vaccine candidate for early clinical testing in a controlled P. falciparum blood stage challenge trial.


Asunto(s)
Vacunas contra la Malaria , Malaria Falciparum , Parásitos , Animales , Ratones , Humanos , Conejos , Receptor Toll-Like 4 , Lípido A , Plasmodium falciparum , Adyuvantes Inmunológicos , Antígenos de Protozoos , Proteínas Protozoarias , Malaria Falciparum/prevención & control , Animales de Laboratorio , Adyuvantes Farmacéuticos , Inmunoglobulina G , Anticuerpos Antiprotozoarios
2.
Chemistry ; 23(57): 14345-14357, 2017 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-28967982

RESUMEN

Malaria remains a major threat to mankind due to the perpetual emergence of resistance against marketed drugs. Twenty-one pyrazolopyran-based inhibitors bearing terminal biphenyl, aryl sulfonamide, or aryl sulfone motifs were synthesized and tested towards serine hydroxymethyltransferase (SHMT), a key enzyme of the folate cycle. The best ligands inhibited Plasmodium falciparum (Pf) and Arabidopsis thaliana (At) SHMT in target, as well as PfNF54 strains in cell-based assays in the low nanomolar range (18-56 nm). Seven co-crystal structures with P. vivax (Pv) SHMT were solved at 2.2-2.6 Šresolution. We observed an unprecedented influence of the torsion angle of ortho-substituted biphenyl moieties on cell-based efficacy. The peculiar lipophilic character of the sulfonyl moiety was highlighted in the complexes with aryl sulfonamide analogues, which bind in their preferred staggered orientation. The results are discussed within the context of conformational preferences in the ligands.

3.
Bioorg Med Chem Lett ; 24(8): 1944-7, 2014 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-24666648

RESUMEN

Bexarotene, a retinoid X receptor (RXR) agonist, is being tested as a potential disease modifying treatment for neurodegenerative conditions. To limit the peripheral exposure of bexarotene and release it only in the affected areas of the brain, we designed a prodrug strategy based on the enzyme NAD(P)H/quinone oxidoreductase (NQO1) that is elevated in neurodegenerative diseases. A series of indolequinones (known substrates of NQO1) was synthesized and coupled to bexarotene. Bexarotene-3-(hydroxymethyl)-5-methoxy-1,2-dimethyl-1H-indole-4,7-dione ester 7a was cleaved best by NQO1. The prodrugs are not cleaved by esterase.


Asunto(s)
Sistemas de Liberación de Medicamentos , Indoles/síntesis química , NAD(P)H Deshidrogenasa (Quinona)/química , Profármacos/síntesis química , Tetrahidronaftalenos/química , Tetrahidronaftalenos/síntesis química , Bexaroteno , Indolquinonas/síntesis química , Indolquinonas/química , Indolquinonas/farmacología , Indoles/química , Indoles/farmacología , Estructura Molecular , Profármacos/química , Profármacos/farmacología , Receptores X Retinoide/agonistas , Tetrahidronaftalenos/farmacología
4.
Cell Rep ; 43(4): 114012, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38573856

RESUMEN

Plasmodium falciparum is a human-adapted apicomplexan parasite that causes the most dangerous form of malaria. P. falciparum cysteine-rich protective antigen (PfCyRPA) is an invasion complex protein essential for erythrocyte invasion. The precise role of PfCyRPA in this process has not been resolved. Here, we show that PfCyRPA is a lectin targeting glycans terminating with α2-6-linked N-acetylneuraminic acid (Neu5Ac). PfCyRPA has a >50-fold binding preference for human, α2-6-linked Neu5Ac over non-human, α2-6-linked N-glycolylneuraminic acid. PfCyRPA lectin sites were predicted by molecular modeling and validated by mutagenesis studies. Transgenic parasite lines expressing endogenous PfCyRPA with single amino acid exchange mutants indicated that the lectin activity of PfCyRPA has an important role in parasite invasion. Blocking PfCyRPA lectin activity with small molecules or with lectin-site-specific monoclonal antibodies can inhibit blood-stage parasite multiplication. Therefore, targeting PfCyRPA lectin activity with drugs, immunotherapy, or a vaccine-primed immune response is a promising strategy to prevent and treat malaria.


Asunto(s)
Eritrocitos , Plasmodium falciparum , Polisacáridos , Proteínas Protozoarias , Humanos , Antígenos de Protozoos/metabolismo , Antígenos de Protozoos/inmunología , Antígenos de Protozoos/genética , Eritrocitos/parasitología , Eritrocitos/metabolismo , Lectinas/metabolismo , Lectinas/genética , Malaria Falciparum/parasitología , Plasmodium falciparum/metabolismo , Polisacáridos/metabolismo , Unión Proteica , Proteínas Protozoarias/metabolismo , Proteínas Protozoarias/genética
5.
Front Bioeng Biotechnol ; 10: 879078, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35669054

RESUMEN

Plasmodium falciparum cysteine-rich protective antigen (PfCyRPA) has been identified as a promising blood-stage candidate antigen to include in a broadly cross-reactive malaria vaccine. In the last couple of decades, substantial effort has been committed to the development of scalable cost-effective, robust, and high-yield PfCyRPA production processes. Despite insect cells being a suitable expression system due to their track record for protein production (including vaccine antigens), these are yet to be explored to produce this antigen. In this study, different insect cell lines, culture conditions (baculovirus infection strategy, supplementation schemes, culture temperature modulation), and purification strategies (affinity tags) were explored aiming to develop a scalable, high-yield, and high-quality PfCyRPA for inclusion in a virosome-based malaria vaccine candidate. Supplements with antioxidants improved PfCyRPA volumetric titers by 50% when added at the time of infection. In addition, from three different affinity tags (6x-His, 4x-His, and C-tag) evaluated, the 4x-His affinity tag was the one leading to the highest PfCyRPA purification recovery yields (61%) and production yield (26 mg/L vs. 21 mg/L and 13 mg/L for 6x-His and C-tag, respectively). Noteworthy, PfCyRPA expressed using High Five cells did not show differences in protein quality or stability when compared to its human HEK293 cell counterpart. When formulated in a lipid-based virosome nanoparticle, immunized rabbits developed functional anti-PfCyRPA antibodies that impeded the multiplication of P. falciparum in vitro. This work demonstrates the potential of using IC-BEVS as a qualified platform to produce functional recombinant PfCyRPA protein with the added benefit of being a non-human expression system with short bioprocessing times and high expression levels.

6.
Eur Radiol ; 21(1): 1-10, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20668860

RESUMEN

OBJECTIVES: Diffusion-weighted MR imaging has shown diagnostic value for differential diagnosis of breast lesions. Diffusion tensor imaging (DTI) adds information about tissue microstructure by addressing diffusion direction. We have examined the diagnostic application of DTI of the breast. METHODS: A total of 59 patients (71 lesions: 54 malignant, 17 benign) successfully underwent prospective echo planar imaging-DTI (EPI-DTI) (1.5 T). First, diffusion direction both of parenchyma as well as lesions was assessed on parametric maps. Subsequently, apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured. Statistics included univariate (Mann-Whitney U test, receiver operating analysis) and multivariate (logistic regression analysis, LRA) tests. RESULTS: Main diffusion direction of parenchyma was anterior-posterior in the majority of cases (66.1%), whereas lesions (benign, malignant) showed no predominant diffusion direction in the majority of cases (23.9%). ADC values showed highest differences between benign and malignant lesions (P<0.001) with resulting area under the curve (AUC) of 0.899. FA values were lower in benign (interquartile range, IR, 0.14-0.24) compared to malignant lesions (IR 0.21-0.35, P<0.002) with an AUC of 0.751-0.770. Following LRA, FA did not prove to have incremental value for differential diagnosis over ADC values. CONCLUSIONS: Microanatomical differences between benign and malignant breast lesions as well as breast parenchyma can be visualized by using DTI.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Imagen de Difusión por Resonancia Magnética , Femenino , Humanos , Proyectos Piloto , Radiografía , Sensibilidad y Especificidad
7.
PLoS Negl Trop Dis ; 14(6): e0008357, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32589646

RESUMEN

Mycolactones, macrolide cytotoxins, are key virulence factors of Mycobacterium ulcerans, the etiological agent of the chronic necrotizing skin disease Buruli ulcer. There is urgent need for a simple point-of-care laboratory test for Buruli ulcer and mycolactone represents a promising target for the development of an immunological assay. However, for a long time, all efforts to generate mycolactone-specific antibodies have failed. By using a protein conjugate of a truncated non-toxic synthetic mycolactone derivative, we recently described generation of a set of mycolactone-specific monoclonal antibodies. Using the first mycolactone-specific monoclonal antibodies that we have described before, we were able to develop an antigen competition assay that detects mycolactones. By the systematic selection of a capturing antibody and a reporter molecule, and the optimization of assay conditions, we developed an ELISA that detects common natural variants of mycolactone with a limit of detection in the low nanomolar range. The mycolactone-specific ELISA described here will be a very useful tool for research on the biology of this macrolide toxin. After conversion into a simple point-of-care test format, the competition assay may have great potential as laboratory assay for both the diagnosis of Buruli ulcer and for the monitoring of treatment efficacy.


Asunto(s)
Ensayo de Inmunoadsorción Enzimática/métodos , Macrólidos/inmunología , Macrólidos/aislamiento & purificación , Mycobacterium ulcerans/metabolismo , Animales , Anticuerpos Monoclonales , Úlcera de Buruli/diagnóstico , Úlcera de Buruli/microbiología , Modelos Animales de Enfermedad , Humanos , Macrólidos/química , Ratones , Ratones Endogámicos BALB C , Técnicas de Diagnóstico Molecular/métodos , Mycobacterium ulcerans/aislamiento & purificación , Sensibilidad y Especificidad
8.
NPJ Vaccines ; 5: 9, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32025340

RESUMEN

The Plasmodium falciparum (Pf) cysteine-rich protective antigen (PfCyRPA) has emerged as a promising blood-stage candidate antigen for inclusion into a broadly cross-reactive malaria vaccine. This highly conserved protein among various geographical strains plays a key role in the red blood cell invasion process by P. falciparum merozoites, and antibodies against PfCyRPA can efficiently prevent the entry of the malaria parasites into red blood cells. The aim of the present study was to develop a human-compatible formulation of the PfCyRPA vaccine candidate and confirming its activity in preclinical studies. Recombinant PfCyRPA expressed in HEK 293 cells was chemically coupled to phosphoethanolamine and then incorporated into the membrane of unadjuvanted influenza virosomes approved as antigen delivery system for humans. Laboratory animals were immunised with the virosome-based PfCyRPA vaccine to determine its immunogenic properties and in particular, its capacity to elicit parasite binding and growth-inhibitory antibodies. The vaccine elicited in mice and rabbits high titers of PfCyRPA-specific antibodies that bound to the blood-stage parasites. At a concentration of 10 mg/mL, purified total serum IgG from immunised rabbits inhibited parasite growth in vitro by about 80%. Furthermore, in a P. falciparum infection mouse model, passive transfer of 10 mg of purified total IgG from PfCyRPA vaccinated rabbits reduced the in vivo parasite load by 77%. Influenza virosomes thus represent a suitable antigen delivery system for the induction of protective antibodies against the recombinant PfCyRPA, designating it as a highly suitable component for inclusion into a multivalent and multi-stage virosomal malaria vaccine.

9.
Biol Chem ; 390(8): 707-15, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19453275

RESUMEN

Mitochondria are highly dynamic organelles forming a tubular network that is sustained by fusion and fission events. Impairment thereof leads to various neuropathies in humans, such as optic atrophy and Parkinson's disease. We have only begun to understand the molecular machineries facilitating fusion and fission of mitochondria and how these processes are regulated. The physiological role of mitochondrial dynamics and how it may be involved in maintaining mitochondrial functionality is still unclear. Here, we discuss current views in this emerging field focusing on the molecular basis of how mitochondrial morphology is regulated and how this may contribute to mitochondrial quality control.


Asunto(s)
Membranas Mitocondriales/fisiología , Miopatías Mitocondriales/fisiopatología , Animales , Enfermedad de Charcot-Marie-Tooth/fisiopatología , Metabolismo Energético , Proteínas de Unión al GTP/fisiología , Humanos , Mitocondrias/fisiología , Proteínas Mitocondriales/fisiología , Proteínas de Saccharomyces cerevisiae/fisiología
10.
ChemMedChem ; 13(9): 931-943, 2018 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-29655285

RESUMEN

With the discovery that serine hydroxymethyltransferase (SHMT) is a druggable target for antimalarials, the aim of this study was to design novel inhibitors of this key enzyme in the folate biosynthesis cycle. Herein, 19 novel spirocyclic ligands based on either 2-indolinone or dihydroindene scaffolds and featuring a pyrazolopyran core are reported. Strong target affinities for Plasmodium falciparum (Pf) SHMT (14-76 nm) and cellular potencies in the low nanomolar range (165-334 nm) were measured together with interesting selectivity against human cytosolic SHMT1 (hSHMT1). Four co-crystal structures with Plasmodium vivax (Pv) SHMT solved at 2.2-2.4 Šresolution revealed the key role of the vinylogous cyanamide for anchoring ligands within the active site. The spirocyclic motif in the molecules enforces the pyrazolopyran core to adopt a substantially more curved conformation than that of previous non-spirocyclic analogues. Finally, solvation of the spirocyclic lactam ring of the receptor-bound ligands is discussed.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Glicina Hidroximetiltransferasa/antagonistas & inhibidores , Indenos/farmacología , Oxindoles/farmacología , Plasmodium/efectos de los fármacos , Compuestos de Espiro/farmacología , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Glicina Hidroximetiltransferasa/metabolismo , Humanos , Indenos/síntesis química , Indenos/química , Ligandos , Modelos Moleculares , Estructura Molecular , Oxindoles/síntesis química , Oxindoles/química , Pruebas de Sensibilidad Parasitaria , Plasmodium/enzimología , Compuestos de Espiro/síntesis química , Compuestos de Espiro/química , Relación Estructura-Actividad
11.
J Med Chem ; 60(12): 4840-4860, 2017 06 22.
Artículo en Inglés | MEDLINE | ID: mdl-28537728

RESUMEN

Target-based approaches toward new antimalarial treatments are highly valuable to prevent resistance development. We report several series of pyrazolopyran-based inhibitors targeting the enzyme serine hydroxymethyltransferase (SHMT), designed to improve microsomal metabolic stability and to identify suitable candidates for in vivo efficacy evaluation. The best ligands inhibited Plasmodium falciparum (Pf) and Arabidopsis thaliana (At) SHMT in target assays and PfNF54 strains in cell-based assays with values in the low nanomolar range (3.2-55 nM). A set of carboxylate derivatives demonstrated markedly improved in vitro metabolic stability (t1/2 > 2 h). A selected ligand showed significant in vivo efficacy with 73% of parasitemia reduction in a mouse model. Five new cocrystal structures with PvSHMT were solved at 2.3-2.6 Å resolution, revealing a unique water-mediated interaction with Tyr63 at the end of the para-aminobenzoate channel. They also displayed the high degree of conformational flexibility of the Cys364-loop lining this channel.


Asunto(s)
Antimaláricos/farmacología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Glicina Hidroximetiltransferasa/antagonistas & inhibidores , Animales , Antimaláricos/química , Proteínas de Arabidopsis/antagonistas & inhibidores , Técnicas de Química Sintética , Cristalografía por Rayos X , Cisteína/química , Estabilidad de Medicamentos , Inhibidores Enzimáticos/metabolismo , Glicina Hidroximetiltransferasa/metabolismo , Semivida , Ligandos , Malaria Falciparum/tratamiento farmacológico , Ratones SCID , Plasmodium falciparum/efectos de los fármacos , Plasmodium falciparum/enzimología , Plasmodium falciparum/patogenicidad , Plasmodium vivax/enzimología , Conformación Proteica , Ratas , Relación Estructura-Actividad , Tiofenos/síntesis química , Tiofenos/farmacología
12.
Oncogene ; 24(12): 2076-86, 2005 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-15688006

RESUMEN

Originally identified in Drosophila melanogaster, the Warts(Wts)/Lats protein kinase has been proposed to function with two other Drosophila proteins, Hippo (Hpo) and Salvador (Sav), in the regulation of cell cycle exit and apoptosis. In mammals, two candidate Warts/Lats homologs, termed Lats1 and Lats2, have been described, and the targeted disruption of LATS1 in mice increases tumor formation. Little, however, is known about the function and regulation of human Lats kinases. Here we report that human Mst2, a STE20-family member and purported Hpo ortholog, phosphorylates and activates both Lats1 and Lats2. Deletion analysis revealed that regulation of Lats1 occurs through the C-terminal, catalytic domain. Within this domain, two regulatory phosphorylation sites were identified by mass spectrometry. These sites, S909 in the activation loop and T1079 within a hydrophobic motif, have been highly conserved during evolution. Moreover, a direct interaction was observed between Mst2 and hWW45, a putative ortholog of Drosophila Sav. These results indicate that Mst2-like kinases regulate Lats kinase activities in an evolutionarily conserved regulatory pathway. Although the function of this pathway remains poorly understood in mammals, it is intriguing that, in Drosophila, it has been linked to development and tissue homeostasis.


Asunto(s)
Proteínas Serina-Treonina Quinasas/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular , Drosophila melanogaster , Regulación de la Expresión Génica , Genes Supresores de Tumor , Células HeLa , Humanos , Riñón , Fragmentos de Péptidos/química , Proteínas Serina-Treonina Quinasas/genética , Serina-Treonina Quinasa 3 , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Proteínas Supresoras de Tumor/metabolismo
13.
J Med Chem ; 59(3): 1232-8, 2016 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-26820900

RESUMEN

The nuclear receptor Nurr1 can be activated by RXR via heterodimerization (RXR-Nurr1) and is a promising target for treating neurodegenerative diseases. We herein report the enantioselective synthesis and SAR of sterically constricted benzofurans at RXR. The established SAR, using whole cell functional assays, lead to the full agonist 9a at RXR (pEC50 of 8.2) and RXR-Nurr1. The X-ray structure shows enantiomeric discrimination where 9a optimally addresses the ligand binding pocket of RXR.


Asunto(s)
Benzofuranos/farmacología , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Multimerización de Proteína/efectos de los fármacos , Receptores X Retinoide/metabolismo , Benzofuranos/síntesis química , Benzofuranos/química , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Humanos , Modelos Moleculares , Estructura Molecular , Miembro 2 del Grupo A de la Subfamilia 4 de Receptores Nucleares/agonistas , Receptores X Retinoide/agonistas , Relación Estructura-Actividad
14.
Nanoscale ; 8(31): 14858-69, 2016 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-27452350

RESUMEN

Medical applications of anticancer and antimalarial drugs often suffer from low aqueous solubility, high systemic toxicity, and metabolic instability. Smart nanocarrier-based drug delivery systems provide means of solving these problems at once. Herein, we present such a smart nanoparticle platform based on self-assembled, reduction-responsive amphiphilic graft copolymers, which were successfully synthesized through thiol-disulfide exchange reaction between thiolated hydrophilic block and pyridyl disulfide functionalized hydrophobic block. These amphiphilic graft copolymers self-assembled into nanoparticles with mean diameters of about 30-50 nm and readily incorporated hydrophobic guest molecules. Fluorescence correlation spectroscopy (FCS) was used to study nanoparticle stability and triggered release of a model compound in detail. Long-term colloidal stability and model compound retention within the nanoparticles was found when analyzed in cell media at body temperature. In contrast, rapid, complete reduction-triggered disassembly and model compound release was achieved within a physiological reducing environment. The synthesized copolymers revealed no intrinsic cellular toxicity up to 1 mg mL(-1). Drug-loaded reduction-sensitive nanoparticles delivered a hydrophobic model anticancer drug (doxorubicin, DOX) to cancer cells (HeLa cells) and an experimental, metabolically unstable antimalarial drug (the serine hydroxymethyltransferase (SHMT) inhibitor (±)-1) to Plasmodium falciparum-infected red blood cells (iRBCs), with higher efficacy compared to similar, non-sensitive drug-loaded nanoparticles. These responsive copolymer-based nanoparticles represent a promising candidate as smart nanocarrier platform for various drugs to be applied to different diseases, due to the biocompatibility and biodegradability of the hydrophobic block, and the protein-repellent hydrophilic block.


Asunto(s)
Antimaláricos/administración & dosificación , Antineoplásicos/administración & dosificación , Portadores de Fármacos/química , Nanopartículas , Doxorrubicina/administración & dosificación , Células HeLa , Humanos , Micelas , Polímeros
15.
Drug Discov Today ; 19(11): 1812-1821, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25173701

RESUMEN

Protein-protein interactions (PPIs) are implicated in every disease and mastering the ability to influence PPIs with small molecules would considerably enlarge the druggable genome. Whereas inhibition of PPIs has repeatedly been shown to work successfully, targeted stabilization of PPIs is underrepresented in the literature. This is all the more surprising because natural products like FK506, rapamycin, brefeldin, forskolin and fusicoccin confer their physiological activity by stabilizing specific PPIs. However, recently a number of very interesting synthetic molecules have been reported from drug discovery projects that indeed achieve their desired activities by stabilizing either homo- or hetero-oligomeric complexes of their target proteins.


Asunto(s)
Descubrimiento de Drogas , Proteínas/metabolismo , Humanos , Preparaciones Farmacéuticas/metabolismo , Estabilidad Proteica/efectos de los fármacos
16.
Future Med Chem ; 6(8): 903-21, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24962282

RESUMEN

One of the proteins that is found in a diverse range of eukaryotic protein-protein interactions is the adaptor protein 14-3-3. As 14-3-3 is a hub protein with very diverse interactions, it is a good model to study various protein-protein interactions. A wide range of classes of molecules, peptides, small molecules or natural products, has been used to modify the protein interactions, providing both stabilization or inhibition of the interactions of 14-3-3 with its binding partners. The first protein crystal structures were solved in 1995 and gave molecular insights for further research. The plant analog of 14-3-3 binds to a plant plasma membrane H(+)-ATPase and this protein complex is stabilized by the fungal phytotoxin fusicoccin A. The knowledge gained from the process in plants was transferred to and applied in human models to find stabilizers or inhibitors of 14-3-3 interaction in human cellular pathways.


Asunto(s)
Proteínas 14-3-3/metabolismo , Productos Biológicos/metabolismo , Péptidos/metabolismo , Proteínas 14-3-3/química , Sitios de Unión , Productos Biológicos/química , Humanos , Péptidos/química , Dominios y Motivos de Interacción de Proteínas , Estructura Terciaria de Proteína , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/metabolismo
17.
MMW Fortschr Med ; 160(6): 74, 2018 Apr.
Artículo en Alemán | MEDLINE | ID: mdl-29619683
18.
MMW Fortschr Med ; 160(8): 58, 2018 May.
Artículo en Alemán | MEDLINE | ID: mdl-29721862
19.
J Med Chem ; 55(22): 9607-18, 2012 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-23043242

RESUMEN

In continuation of our previous work, several 1-alkyl-2,3,5-tris(4-hydroxyphenyl)aryl-1H-pyrroles with chlorine or fluorine substituents in the aryl residues were synthesized and tested for estrogen receptor (ER) binding at isolated ERα/ERß receptors (HAP assay) and in transactivation assays using ERα-positive MCF-7/2a as well as U2-OS/ERα and U2-OS/ERß cells. In the competition experiment at ERα the compounds displayed very high relative binding affinities of up to 37% (determined for 8m) but with restricted subtype selectivity (e.g., ERα/ERß (8m) = 9). The highest estrogenic potency in ERα-positive MCF-7/2a cells was determined for 2,3,5-tris(2-fluoro-4-hydroxyphenyl)-1-propyl-1H-pyrrole 8m (EC(50) = 23 nM), while in U2-OS/ERα cells 2-(2-fluoro-4-hydroxyphenyl)-3,5-bis(4-hydroxyphenyl)-1-propyl-1H-pyrrole 8b (EC(50) = 0.12 nM) was the most potent agonist, only 30-fold less active than estradiol (E2, EC(50) = 0.004 nM). In U2-OS/ERß cells for all pyrroles no transactivation could be observed, which indicates that they are selective ERα agonists in cellular systems.


Asunto(s)
Proliferación Celular/efectos de los fármacos , Cloro/química , Receptor alfa de Estrógeno/agonistas , Receptor beta de Estrógeno/agonistas , Flúor/química , Fenoles/farmacología , Pirroles/farmacología , Western Blotting , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/metabolismo , Receptor alfa de Estrógeno/metabolismo , Receptor beta de Estrógeno/metabolismo , Femenino , Humanos , Luciferasas/metabolismo , Modelos Moleculares , Osteosarcoma/tratamiento farmacológico , Osteosarcoma/metabolismo , Fenoles/química , Unión Proteica , Pirroles/química , Relación Estructura-Actividad , Células Tumorales Cultivadas
20.
ChemMedChem ; 6(5): 794-803, 2011 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-21416612

RESUMEN

In this study, we synthesized 1,2,4-triarylpyrroles as ligands for the estrogen receptor (ER). Two pyrrole series were prepared with either C3-alkyl or C3/C5-dialkyl residues. Compounds from both series were susceptible to oxidative degradation-dialkylated compounds (t(1/2) =33-66 h) to a higher extent than their monoalkylated congeners (t(1/2) =140-211 h). Nevertheless, stability was sufficient for determination of in vitro ER binding affinity. The most active agonist in hormone-dependent, ERα-positive MCF-7/2a and U2-OS/α cells was 1,2,4-tris(4-hydroxyphenyl)-3-propyl-1H-pyrrole (6 d) (MCF-7/2a: EC(50) =70 nM; U2-OS/α: EC(50) =1.6 nM). A corresponding inactivity in U2-OS/ß cells demonstrated the high ERα selectivity. This trend was confirmed in a competition experiment using estradiol (E2) and purified hERα and hERß proteins (relative binding affinity (RBA) calculated for 6 d: RBA(ERα)=1.85 %; RBA(ERß) <0.01 %). Generally, C3/C5-dialkyl substitution led to reduction of activity, possibly due to lower stability.


Asunto(s)
Antineoplásicos/síntesis química , Receptor alfa de Estrógeno/química , Pirroles/química , Antineoplásicos/química , Antineoplásicos/toxicidad , Línea Celular Tumoral , Diseño de Fármacos , Receptor alfa de Estrógeno/metabolismo , Humanos , Ligandos , Oxidación-Reducción , Unión Proteica , Pirroles/síntesis química , Pirroles/toxicidad , Relación Estructura-Actividad
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