RESUMEN
An O-methyltyrosine-containing azadipeptide nitrile was synthesised and investigated for its inhibitory activity towards cathepsins L, S, K, and B. Labelling with carbon-11 was accomplished by reaction of the corresponding phenolic precursor with [11 C]methyl iodide starting from cyclotron-produced [11 C]methane. Radiopharmacological evaluation of the resulting radiotracer in a mouse xenograft model derived from a mammary tumour cell line by small animal PET imaging indicates tumour targeting with complex pharmacokinetics. Radiotracer uptake in the tumour region was considerably lower under treatment with the nonradioactive reference compound and the epoxide-based irreversible cysteine cathepsin inhibitor E64. The in vivo behaviour observed for this radiotracer largely confirms that of the corresponding 18 F-fluoroethylated analogue and suggests the limited suitability of azadipeptide nitriles for the imaging of tumour-associated cysteine cathepsins despite target-mediated uptake is evidenced.
Asunto(s)
Radioisótopos de Carbono , Catepsinas/metabolismo , Cisteína/metabolismo , Dipéptidos/química , Nitrilos/química , Nitrilos/síntesis química , Tomografía de Emisión de Positrones/métodos , Animales , Transporte Biológico , Línea Celular Tumoral , Técnicas de Química Sintética , Femenino , Humanos , Ratones , Ratones Desnudos , Nitrilos/metabolismo , Trazadores RadiactivosRESUMEN
Cleavage of the invariant chain is the key event in the trafficking pathway of major histocompatibility complex classâ II. Cathepsinâ S is the major processing enzyme of the invariant chain, but cathepsinâ F acts in macrophages as its functional synergist which is as potent as cathepsinâ S in invariant chain cleavage. Dedicated low-molecular-weight inhibitors for cathepsinâ F have not yet been developed. An active site mapping with 52 dipeptide nitriles, reacting as covalent-reversible inhibitors, was performed to draw structure-activity relationships for the non-primed binding region of human cathepsinâ F. In a stepwise process, new compounds with optimized fragment combinations were designed and synthesized. These dipeptide nitriles were evaluated on human cysteine cathepsinsâ F, B, L, K and S. Compounds 10 (N-(4-phenylbenzoyl)-leucylglycine nitrile) and 12 (N-(4-phenylbenzoyl)leucylmethionine nitrile) were found to be potent inhibitors of human cathepsinâ F, with Ki values <10â nM. With all dipeptide nitriles from our study, a 3D activity landscape was generated to visualize structure-activity relationships for this series of cathepsinâ F inhibitors.
Asunto(s)
Catepsina F/antagonistas & inhibidores , Inhibidores de Cisteína Proteinasa/química , Dipéptidos/química , Nitrilos/química , Sitios de Unión , Dominio Catalítico , Catepsina F/metabolismo , Inhibidores de Cisteína Proteinasa/síntesis química , Inhibidores de Cisteína Proteinasa/metabolismo , Humanos , Simulación del Acoplamiento Molecular , Nitrilos/síntesis química , Nitrilos/metabolismo , Unión Proteica , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/metabolismo , Relación Estructura-ActividadRESUMEN
An activity-based probe, containing an irreversibly locked GFP-like fluorophore, was synthesized and evaluated as an inhibitor of human cathepsins and, as exemplified with cathepsin K, it proved to be suitable for ex vivo imaging and quantification of cysteine cathepsins by SDS-PAGE.
Asunto(s)
Catepsinas/análisis , Cisteína/análisis , Electroforesis en Gel de Poliacrilamida/métodos , Colorantes Fluorescentes/análisis , Proteínas Fluorescentes Verdes/análisis , Catepsina K/análisis , Fluorescencia , Células HEK293 , HumanosRESUMEN
A fluorinated cathepsin inhibitor based on the azadipeptide nitrile chemotype was prepared and selected for positron emission tomography (PET) tracer development owing to its high affinity for the oncologically relevant cathepsins L, S, K and B. Labelling with fluorine-18 was accomplished in an efficient and reliable two-step, one-pot radiosynthesis by using 2-[(18) F]fluoroethylnosylate as a prosthetic agent. The pharmacokinetic properties of the resulting radiotracer compound were studied inâ vitro, exâ vivo and inâ vivo in normal rats by radiometabolite analysis and small-animal positron emission tomography. These investigations revealed rapid conjugate formation of the tracer with glutathione in the blood, which is associated with slow blood clearance. The potential of the developed (18) F-labelled probe to image tumour-associated cathepsin activity was investigated by dynamic small-animal PET imaging in nude mice bearing tumours derived from the human NCI-H292 lung carcinoma cell line. Computational analysis of the obtained image data indicated the time-dependent accumulation of the radiotracer in the tumours. The expression of the target enzymes in the tumours was confirmed by immunohistochemistry with specific antibodies. This indicates that azadipeptide nitriles have the potential to target thiol-dependent cathepsins inâ vivo despite their disadvantageous pharmacokinetics.
Asunto(s)
Compuestos Aza/química , Catepsinas/metabolismo , Dipéptidos/química , Radioisótopos de Flúor/química , Nitrilos/química , Radiofármacos/síntesis química , Animales , Catepsinas/química , Línea Celular Tumoral , Dipéptidos/farmacocinética , Semivida , Humanos , Cinética , Ratones , Neoplasias/diagnóstico por imagen , Tomografía de Emisión de Positrones , Radiofármacos/farmacocinética , Ratas , Ratas Wistar , Distribución Tisular , Trasplante HeterólogoRESUMEN
Cysteine cathepsins play an important role in many (patho)physiological conditions. Among them, cathepsins L, S, K and B are subjects of several drug discovery programs. Besides their role as drug targets, cysteine cathepsins are additionally considered to be possible biomarkers for inflammation and cancer. Herein, we describe the design, synthesis, biological evaluation and spectral properties of fluorescently labeled dipeptide- and azadipeptide nitriles.
Asunto(s)
Catepsinas/antagonistas & inhibidores , Inhibidores de Cisteína Proteinasa/farmacología , Dipéptidos/química , Fluorescencia , Nitrilos/farmacología , Catepsinas/metabolismo , Inhibidores de Cisteína Proteinasa/síntesis química , Inhibidores de Cisteína Proteinasa/química , Relación Dosis-Respuesta a Droga , Diseño de Fármacos , Estructura Molecular , Nitrilos/síntesis química , Nitrilos/química , Relación Estructura-ActividadRESUMEN
A series of dipeptide nitriles with different P3 substituents was designed to explore the S3 binding pocket of cathepsin S. Racemic 7-16 and the enantiopure derivative (R)-22 proved to be potent inhibitors of human cathepsin S and exhibited notable selectivity over human cathepsins L, K, and B. Inhibition of cathepsin F, the functional synergist of cathepsin S, was not observed. The azadipeptide analogue of 22, compound 26, was highly potent but nonselective.
Asunto(s)
Catepsina F/antagonistas & inhibidores , Catepsina F/metabolismo , Catepsinas/antagonistas & inhibidores , Catepsinas/metabolismo , Nitrilos/farmacología , Inhibidores de Proteasas/farmacología , Proteolisis/efectos de los fármacos , Dipéptidos/química , Humanos , Concentración 50 Inhibidora , Cinética , Nitrilos/síntesis química , Nitrilos/química , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/química , Especificidad por SustratoAsunto(s)
Catepsina K/síntesis química , Dipéptidos/síntesis química , Inhibidores Enzimáticos/farmacología , Leucina/química , Nitrilos/farmacología , Catepsina K/química , Dipéptidos/química , Diseño de Fármacos , Inhibidores Enzimáticos/química , Enlace de Hidrógeno , Estructura Molecular , Nitrilos/químicaAsunto(s)
Catepsina B/antagonistas & inhibidores , Dipéptidos/síntesis química , Dipéptidos/farmacología , Diseño de Fármacos , Hidrocarburos Fluorados/síntesis química , Hidrocarburos Fluorados/farmacología , Nitrilos/síntesis química , Nitrilos/farmacología , Técnicas Químicas Combinatorias , Dipéptidos/química , Humanos , Hidrocarburos Fluorados/química , Estructura Molecular , Nitrilos/química , EstereoisomerismoRESUMEN
Using the example of cathepsin K, we demonstrate the design of highly potent and selective azadipeptide nitrile inhibitors. A systematic scan with respect to P2 and P3 substituents was carried out. Structural modifications strongly affected the enzyme-inhibitor association (but not dissociation) rate. A combination of optimized P2 and P3 substituents with a methylation of the P3-P2 amide linker resulted in the picomolar cathepsin K inhibitor 19 with remarkable selectivity over cathepsins L, B, and S.
Asunto(s)
Compuestos Aza/síntesis química , Catepsina K/antagonistas & inhibidores , Dipéptidos/síntesis química , Nitrilos/síntesis química , Compuestos Aza/química , Catepsina K/química , Dipéptidos/química , Cinética , Nitrilos/química , Relación Estructura-ActividadRESUMEN
It is now becoming clear that several papain-like cysteine cathepsins are involved in the pathophysiology of diseases such as osteoporosis, autoimmune disorders, and cancer. Therefore, the development of potent and selective cathepsin inhibitors is an attractive subject for medicinal chemists. New advances have been made for nitrile-based inhibitors, leading to the identification of the cathepsin K inhibitor odanacatib and other candidates with potential for therapeutic use. This review summarizes the development of peptidic and peptidomimetic compounds with an electrophilic nitrile 'warhead' as inhibitors of the cysteine cathepsins B, S, L, C, and K. Peptide nitriles have been shown to reversibly react with the active site cysteine under formation of a covalent thioimidate adduct. The structural optimization with respect to the positions P3, P2, P1, P1', and P2' resulted in the identification of potent and selective inhibitors of the corresponding cathepsins. The underlying structure-activity relationships are discussed herein.
Asunto(s)
Catepsinas/antagonistas & inhibidores , Diseño de Fármacos , Nitrilos/farmacología , Péptidos/farmacología , Animales , Dominio Catalítico/efectos de los fármacos , Catepsinas/metabolismo , Humanos , Nitrilos/síntesis química , Nitrilos/química , Péptidos/síntesis química , Péptidos/química , Relación Estructura-ActividadRESUMEN
Azadipeptide nitriles-novel cysteine protease inhibitors-display structure-dependent antimalarial activity against both chloroquine-sensitive and chloroquine-resistant lines of cultured Plasmodium falciparum malaria parasites. Inhibition of parasite's hemoglobin-degrading cysteine proteases was also investigated, revealing the azadipeptide nitriles as potent inhibitors of falcipain-2 and -3. A correlation between the cysteine protease-inhibiting activity and the antimalarial potential of the compounds was observed. These first generation azadipeptide nitriles represent a promising new class of compounds for antimalarial drug development.
Asunto(s)
Antimaláricos/química , Compuestos Aza/química , Cisteína Endopeptidasas/química , Inhibidores de Cisteína Proteinasa/química , Dipéptidos/química , Nitrilos/química , Antimaláricos/síntesis química , Antimaláricos/farmacología , Cisteína Endopeptidasas/metabolismo , Inhibidores de Cisteína Proteinasa/síntesis química , Inhibidores de Cisteína Proteinasa/farmacología , Nitrilos/síntesis química , Nitrilos/farmacología , Plasmodium falciparum/efectos de los fármacosRESUMEN
The synthesis of a series of new isothiazol-3(2H)-one 1,1-dioxides with halogenated (mostly fluorinated) pyridinyl and pentafluorophenyl substituents at 2-position is reported. These compounds (18-24) became easily accessible from 2-thiocyanato-1-carboxaldehydes and aminopyridines, pentafluoroaniline, respectively, by an isothiazolium cyclization-oxidation route. Compound 21 exhibited an IC(50) value of 3.1 microM toward human leukocyte elastase. The proteases cathepsin G, trypsin, cathepsin L, and angiotensin-converting enzyme, and the serine esterases acetylcholinesterase and cholesterol esterase were not inhibited by 21.
Asunto(s)
Óxidos S-Cíclicos/síntesis química , Óxidos S-Cíclicos/farmacología , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Elastasa de Leucocito/antagonistas & inhibidores , Acetilcolinesterasa/efectos de los fármacos , Catepsina G , Catepsina L , Catepsinas/antagonistas & inhibidores , Cristalografía por Rayos X , Óxidos S-Cíclicos/química , Ciclización , Cisteína Endopeptidasas , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/química , Humanos , Modelos Moleculares , Estructura Molecular , Oxidación-Reducción , Peptidil-Dipeptidasa A/efectos de los fármacos , Serina Endopeptidasas , Estereoisomerismo , Esterol Esterasa/antagonistas & inhibidores , Relación Estructura-Actividad , Tripsina/efectos de los fármacosAsunto(s)
Compuestos Aza/química , Inhibidores de Cisteína Proteinasa/química , Dipéptidos/química , Nitrilos/química , Papaína/antagonistas & inhibidores , Compuestos Aza/síntesis química , Compuestos Aza/farmacología , Inhibidores de Cisteína Proteinasa/síntesis química , Inhibidores de Cisteína Proteinasa/farmacología , Dipéptidos/síntesis química , Dipéptidos/farmacología , Humanos , Nitrilos/síntesis química , Nitrilos/farmacologíaRESUMEN
Modifications of the Zwikker- and Parri color detection tests were examined and compared according to their ability to distinguish between nine different barbituric acids and hydantoins. These tests comprised the formation of complexes with cobalt(II) and copper(II) salts and organic amines. Using the color palette introduced herein, the evaluation of the tests could be reduced to a simple yes/no decision on the basis of only seven defined colors. Suitable components for the color tests could be selected from the thirty six modifications.