RESUMEN
BACKGROUND: Members of the cytochrome P450 1A family metabolize many procarcinogens such as polycyclicaromatic hydrocarbons and heterocyclic amines. Inactivation of these enzymes is a prerequisite for cancer prevention and treatment in certain cases. Mechanism-based inhibition (time and co-factor dependent) is an effective method for the inactivation of these enzymes. Our recent study on emodin analogs revealed an anthraquinone with ortho-methylarylamine moiety that exhibited timedependent inhibition of P450 enzymes 1A1 and 1A2. METHODS: To determine whether the amino group or the methyl group or both were responsible for the time-dependent inhibition of these enzymes, a set of eleven compounds containing the orthomethylarylamine moiety were identified through a database search, and studied for the inhibition of the P450 enzymes 1A1, 1A2, 2A6 and 2B1. Our earlier studies on carbazole derivatives provided us with highly selective P450 1A2 inhibitors. Glycine scanning studies were performed on the docked proteinligand complexes of compounds 1-20 in order to understand the contribution of different protein residues towards the ligand binding. RESULTS: Four compounds were found to cause selective time-dependent inhibition of P450 1A1 with KI values ranging from 0.24 to 8.25 mM. These compounds exhibited only direct inhibition of P450 1A2. Molecular modeling studies of these molecules indicated that the shapes of the molecules, their binding modes, and the methyl substituent in close proximity (4.5-5.7 Å) to the heme-Fe all contributed to their selective time-dependent inhibition activity on P450 1A1. Glycine scanning studies for P450 1A1 indicated that ligand interaction with Phe123 was the strongest binding contributor and similar studies for P450 1A2 indicated that ligand interactions with the phenylalanine residues 226 and 260 were the largest binding contributors. CONCLUSION: Four compounds have been identified that exhibit selective time-dependent inhibition of P450 1A1. Modeling studies have indicated that the proximity of the aromatic methyl group to the heme-Fe could be the main contributor for time-dependent inhibition. Future studies will focus on the confirmation of the involvement of the aromatic methyl group in enzyme inactivation.
Asunto(s)
Antraquinonas/farmacología , Citocromo P-450 CYP1A1/metabolismo , Inhibidores del Citocromo P-450 CYP1A2/farmacología , Citocromo P-450 CYP1A2/metabolismo , Pruebas de Enzimas , Humanos , Concentración 50 Inhibidora , Ligandos , Simulación del Acoplamiento Molecular , Fenilalanina/metabolismo , Unión Proteica , Factores de TiempoRESUMEN
PIM1 is a proto-oncogene encoding the serine/threonine PIM1 kinase. PIM1 kinase plays important roles in regulating aspects of cell cycle progression, apoptosis resistance, and has been implicated in the development of such malignancies as prostate cancer and acute myeloid leukemia among others. Knockout of PIM1 kinase in mice has been shown to be non-lethal without any obvious phenotypic changes, making it an attractive therapeutic target. Our investigation of anthraquinones as kinase inhibitors revealed a series of quinone analogs showing high selectivity for inhibition of the PIM kinases. Molecular modeling studies were used to identify key interactions and binding poses of these compounds within the PIM1 binding pocket. Compounds 1, 4, 7 and 9 inhibited the growth of DU-145 prostate cancer cell lines with a potency of 8.21µM, 4.06µM, 3.21µM and 2.02µM.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias de la Próstata/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas c-pim-1/antagonistas & inhibidores , Quinonas/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Masculino , Estructura Molecular , Neoplasias de la Próstata/patología , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas c-pim-1/metabolismo , Quinonas/síntesis química , Quinonas/química , Relación Estructura-ActividadRESUMEN
Cytochrome P450's (CYP's) constitute a diverse group of over 500 monooxygenase hemoproteins, catalyzing transformations that involve xenobiotic metabolism, steroidogenesis and other metabolic processes. Over-production of the steroid hormone cortisol is implicated in the progression of diseases such as diabetes, heart failure and hypertension, stroke, Cushing's syndrome, obesity and renal failure, among others. The biosynthesis of cortisol involves a cascade of cholesterol metabolizing reactions regulated through three major CYP proteins: 17α-hydroxylase-C17/20-lyase (CYP17), 21-hydroxylase (CYP21), and 11ß-hydroxylase (CYP11B1). Excess activities of these enzymes are linked to the progression of malignancies including prostate, breast, ovarian, and uterine cancers. A series of novel functionalized dioxane analogs have been developed and recently patented as CYP17, CYP21, and CYP11B1 inhibitors, which lead to the modulation of cortisol production as a method for treating, delaying, slowing, and inhibiting the implicated diseases. The findings disclosed in this patent have been analyzed and compared with the literature data on inhibitors of CYP17, CYP21, and CYP11B1. The compiled data provide insight into the novel functionality of the compounds described in the patent. In this regard, an objective opinion on the effectiveness and novel biochemistry of these compounds in comparison to current CYP inhibitors used in the treatment of cortisol-related diseases is presented in this paper.
Asunto(s)
Inhibidores Enzimáticos del Citocromo P-450/farmacología , Dioxanos/farmacología , Hidrocortisona/metabolismo , Inhibidores Enzimáticos del Citocromo P-450/química , Dioxanos/química , Diseño de Fármacos , Humanos , Patentes como Asunto , Esteroide 11-beta-Hidroxilasa/antagonistas & inhibidores , Esteroide 11-beta-Hidroxilasa/metabolismo , Esteroide 17-alfa-Hidroxilasa/antagonistas & inhibidores , Esteroide 17-alfa-Hidroxilasa/metabolismo , Esteroide 21-Hidroxilasa/antagonistas & inhibidores , Esteroide 21-Hidroxilasa/metabolismoRESUMEN
One new sodium salt of an iridoid acid, sodium 6-O-methyldeacetylasperulosidate (1) and one new heterocyclic compound, 1,3,6-trimethylpyrano[2,3- d]imidazole-2,5(1H,3H)-dione (2) were isolated from Hedyotis lindleyana Hook. (Rubiaceae), together with seven known compounds, oleanolic acid (3), ursolic acid (4), teneoside D (5), 6ß-hydroxygeniposide (6), deacetylasperulosidic acid sodium salt (7), liquiritin (8), and 3,3',4'-tri-O-methylellagic acid (9). The structures were established by spectroscopic (1D, 2D NMR) and HR-ESI-MS analysis, as well as by comparison with data reported in the literature.
Asunto(s)
Hedyotis/química , Imidazoles/aislamiento & purificación , Iridoides/aislamiento & purificación , Piranos/aislamiento & purificación , Imidazoles/química , Iridoides/química , Estructura Molecular , Ácido Oleanólico/aislamiento & purificación , Piranos/química , Triterpenos/aislamiento & purificación , Ácido UrsólicoRESUMEN
A voltammetric method based on a combination of incorporated Nafion, single-walled carbon nanotubes and poly(3-methylthiophene) film-modified glassy carbon electrode (NF/SWCNT/PMT/GCE) has been successfully developed for selective determination of dopamine (DA) in the ternary mixture of dopamine, ascorbic acid (AA) and uric acid (UA) in 0.1M phosphate buffer solution (PBS) pH 4. It was shown that to detect DA from binary DA-AA mixture, the use of NF/PMT/GCE was sufficient, but to detect DA from ternary DA-AA-UA mixture NF/SWCNT/PMT/GCE was required. The later modified electrode exhibits superior electrocatalytic activity towards AA, DA and UA thanks to synergic effect of NF/SWCNT (combining unique properties of SWCNT such as high specific surface area, electrocatalytic and adsorptive properties, with the cation selectivity of NF). On the surface of NF/SWCNT/PMT/GCE AA, DA, UA were oxidized respectively at distinguishable potentials of 0.15, 0.37 and 0.53 V (vs. Ag/AgCl), to form well-defined and sharp peaks, making possible simultaneous determination of each compound. Also, it has several advantages, such as simple preparation method, high sensitivity, low detection limit and excellent reproducibility. Thus, the proposed NF/SWCNT/PMT/GCE could be advantageously employed for the determination of DA in real pharmaceutical formulations.