RÉSUMÉ
We designed and prepared synthetic phospholipids that generate lyso-phosphatidylcholine products with a unique mass for convenient detection by LC-MS in complex biological matrices. We demonstrated that compound 4, formulated either as a Triton X-100 emulsion or incorporated in synthetic HDL particles can serve as a substrate for plasma EL with useful specificity.
Sujet(s)
Antienzymes/pharmacologie , Triacylglycerol lipase/antagonistes et inhibiteurs , Phospholipides/pharmacologie , Relation dose-effet des médicaments , Antienzymes/synthèse chimique , Antienzymes/composition chimique , Humains , Triacylglycerol lipase/sang , Triacylglycerol lipase/métabolisme , Structure moléculaire , Phospholipides/synthèse chimique , Phospholipides/composition chimique , Relation structure-activitéRÉSUMÉ
Human clinical studies conducted with LCI699 established aldosterone synthase (CYP11B2) inhibition as a promising novel mechanism to lower arterial blood pressure. However, LCI699's low CYP11B1/CYP11B2 selectivity resulted in blunting of adrenocorticotropic hormone-stimulated cortisol secretion. This property of LCI699 prompted its development in Cushing's disease, but limited more extensive clinical studies in hypertensive populations, and provided an impetus for the search for cortisol-sparing CYP11B2 inhibitors. This paper summarizes the discovery, pharmacokinetics, and pharmacodynamic data in preclinical species and human subjects of the selective CYP11B2 inhibitor 8.
Sujet(s)
Cytochrome P-450 CYP11B2/antagonistes et inhibiteurs , Antienzymes/composition chimique , Indoles/composition chimique , Antagonistes des récepteurs des minéralocorticoïdes/composition chimique , Pyridines/composition chimique , Sulfonamides/composition chimique , Aldostérone/métabolisme , Animaux , Cytochrome P-450 CYP11B2/métabolisme , Antienzymes/pharmacocinétique , Antienzymes/pharmacologie , Halogénation , Haplorhini , Humains , Hypertension artérielle/traitement médicamenteux , Indoles/pharmacocinétique , Indoles/pharmacologie , Méthylation , Antagonistes des récepteurs des minéralocorticoïdes/pharmacocinétique , Antagonistes des récepteurs des minéralocorticoïdes/pharmacologie , Pyridines/pharmacocinétique , Pyridines/pharmacologie , Rats , Rat Sprague-Dawley , Sulfonamides/pharmacocinétique , Sulfonamides/pharmacologieRÉSUMÉ
CYP11B2, the aldosterone synthase, and CYP11B1, the cortisol synthase, are two highly homologous enzymes implicated in a range of cardiovascular and metabolic diseases. We have previously reported the discovery of LCI699, a dual CYP11B2 and CYP11B1 inhibitor that has provided clinical validation for the lowering of plasma aldosterone as a viable approach to modulate blood pressure in humans, as well normalization of urinary cortisol in Cushing's disease patients. We now report novel series of aldosterone synthase inhibitors with single-digit nanomolar cellular potency and excellent physicochemical properties. Structure-activity relationships and optimization of their oral bioavailability are presented. An illustration of the impact of the age of preclinical models on pharmacokinetic properties is also highlighted. Similar biochemical potency was generally observed against CYP11B2 and CYP11B1, although emerging structure-selectivity relationships were noted leading to more CYP11B1-selective analogs.
Sujet(s)
Cytochrome P-450 CYP11B2/antagonistes et inhibiteurs , Antienzymes/pharmacologie , Antienzymes/pharmacocinétique , Microsomes du foie/effets des médicaments et des substances chimiques , Steroid 11-beta-hydroxylase/antagonistes et inhibiteurs , Aldostérone/pharmacologie , Animaux , Anti-inflammatoires/pharmacologie , Corticostérone/pharmacologie , Antienzymes/composition chimique , Imidazoles/pharmacologie , Mâle , Microsomes du foie/enzymologie , Modèles moléculaires , Structure moléculaire , Pyridines/pharmacologie , Rats , Rat Sprague-Dawley , Relation structure-activité , Distribution tissulaireRÉSUMÉ
3ß,16ß,17α-Trihydroxycholest-5-en-22-one 16-O-(2-O-4-methoxybenzoyl-ß-D-xylopyranosyl)-(1â3)-2-O-acetyl-α-L-arabinopyranoside (OSW-1) is a natural product with potent antitumor activity against various types of cancer cells, but the exact mechanisms of action remain to be defined. In this study, we showed that OSW-1 effectively killed leukemia cells at subnanomolar concentrations through a unique mechanism by causing a time-dependent elevation of cytosolic Ca(2+) prior to induction of apoptosis. A mechanistic study revealed that this compound inhibited the sodium-calcium exchanger 1 on the plasma membrane, leading to an increase in cytosolic Ca(2+) and a decrease in cytosolic Na(+). The elevated cytosolic Ca(2+) caused mitochondrial calcium overload and resulted in a loss of mitochondrial membrane potential, release of cytochrome c, and activation of caspase-3. Furthermore, OSW-1 also caused a Ca(2+)-dependent cleavage of the survival factor GRP78. Inhibition of Ca(2+) entry into the mitochondria by the uniporter inhibitor RU360 or by cyclosporin A significantly prevented the OSW-1-induced cell death, indicating the important role of mitochondria in mediating the cytotoxic activity. The extremely potent activity of OSW-1 against leukemia cells and its unique mechanism of action suggest that this compound may be potentially useful in the treatment of leukemia.
Sujet(s)
Produits biologiques/pharmacologie , Calcium/métabolisme , Cholesténones/pharmacologie , Homéostasie/effets des médicaments et des substances chimiques , Leucémies/métabolisme , Leucémies/anatomopathologie , Saponines/pharmacologie , Canaux calciques/métabolisme , Calpain/métabolisme , Caspase-3/métabolisme , Mort cellulaire/effets des médicaments et des substances chimiques , Lignée cellulaire tumorale , Ciclosporine/pharmacologie , Cytochromes c/métabolisme , Cytosol/effets des médicaments et des substances chimiques , Cytosol/métabolisme , Tests de criblage d'agents antitumoraux , Réticulum endoplasmique/effets des médicaments et des substances chimiques , Réticulum endoplasmique/métabolisme , Chaperonne BiP du réticulum endoplasmique , Activation enzymatique/effets des médicaments et des substances chimiques , Espace extracellulaire/effets des médicaments et des substances chimiques , Espace extracellulaire/métabolisme , Protéines du choc thermique/métabolisme , Humains , Leucémies/enzymologie , Lymphomes/enzymologie , Lymphomes/anatomopathologie , Potentiel de membrane mitochondriale/effets des médicaments et des substances chimiques , Mitochondries/effets des médicaments et des substances chimiques , Mitochondries/métabolisme , Échangeur sodium-calcium/antagonistes et inhibiteurs , Échangeur sodium-calcium/métabolisme , Thapsigargine/pharmacologie , Facteurs tempsRÉSUMÉ
OSW-1 is a highly potent anticancer natural saponin with an unknown mode of action. To determine its cellular target(s) biotinylated OSW-1 was successfully synthesized in nine steps.
Sujet(s)
Antinéoplasiques d'origine végétale/synthèse chimique , Antinéoplasiques d'origine végétale/toxicité , Biotine/analogues et dérivés , Cholesténones/composition chimique , Saponines/synthèse chimique , Antinéoplasiques d'origine végétale/composition chimique , Biotine/synthèse chimique , Biotine/composition chimique , Biotine/toxicité , Biotinylation , Lignée cellulaire tumorale , Cholesténones/synthèse chimique , Cholesténones/toxicité , Humains , Saponines/composition chimique , Saponines/toxicitéRÉSUMÉ
The naturally occurring compound 3beta,16beta,17alpha-trihydroxycholest-5-en-22-one 16-O-(2-O-4-methoxybenzoyl-beta-D-xylopyranosyl)-(1-->3)-(2-O-acetyl-alpha-L-arabinopyranoside) (OSW-1) is found in the bulbs of Ornithogalum saudersiae and is highly cytotoxic against tumor cell lines. Using various human cancer and nonmalignant cell lines, we investigated the anticancer activity and selectivity of OSW-1 and its underlying mechanisms of action. OSW-1 exhibited extremely potent cytotoxic activity against cancer cells in vitro. Nonmalignant cells were statistically significantly less sensitive to OSW-1 than cancer cells, with concentrations that cause a 50% loss of cell viability 40-150-fold greater than those observed in malignant cells. Electron microscopy and biochemical analyses revealed that OSW-1 damaged the mitochondrial membrane and cristae in both human leukemia and pancreatic cancer cells, leading to the loss of transmembrane potential, increase of cytosolic calcium, and activation of calcium-dependent apoptosis. Clones of leukemia cells with mitochondrial DNA defects and respiration deficiency that had adapted the ability to survive in culture without mitochondrial respiration also were resistant to OSW-1. In vitro analysis revealed that OSW-1 effectively killed primary leukemia cells from chronic lymphocytic leukemia patients with disease refractory to fludarabine. The promising anticancer activity of OSW-1 and its unique mechanism of action make this compound worthy of further investigation for its potential to overcome drug resistance.
Sujet(s)
Antinéoplasiques/pharmacologie , Apoptose/effets des médicaments et des substances chimiques , Cholesténones/pharmacologie , Leucémie chronique lymphocytaire à cellules B/traitement médicamenteux , Membranes mitochondriales/effets des médicaments et des substances chimiques , Saponines/pharmacologie , Canaux calciques/métabolisme , Lignée cellulaire tumorale , Résistance aux médicaments antinéoplasiques , Humains , Concentration inhibitrice 50 , Microscopie électronique , Vidarabine/analogues et dérivés , Vidarabine/pharmacologieRÉSUMÉ
High-performance capillary electrophoresis with electrochemical detection was employed to analyse active ingredients of Rhododendron dauricum L., an important crude herb frequently used in Chinese medicines. Farrerol, quercetin, syringic acid, vanillic acid, 4-hydroxybenzoic acid, protocatechuic acid are major important active ingredients. Operated in a wall-jet configuration, a 300-microm diameter carbon-disk electrode was used as the working electrode, which exhibits a good response at +950 mV (vs. saturated calomel electrodes) for six analytes. Under the optimum conditions, the analytes were baseline separated within 16 min in a borax buffer (pH 8.7). Notably, excellent linearity was obtained over two orders of magnitude with detection limits (S/N=3) ranged from 9 x 10(-7) to 3.0 x 10(-6) M for all analytes. This method was successfully used in the analysis of Rhododendron dauricum L. with relatively simple extraction procedures, and the assay results were satisfactory.