ABSTRACT
Deoxycholic acid derivatives were designed as P-glycoprotein (Pgp, ABCB1) inhibitors. Thus the synthesis and the biological activity of methyl deoxycholate derivatives 5-10 and their ether analogs 15-20 have been reported. The potency of these compounds to modulate Pgp-mediated MDR was evaluated through daunorubicin accumulation and potentiation of doxorubicin cytotoxicity in K562/R7 multidrug resistant cells overexpressing Pgp. In parallel, their intrinsic toxicity was appreciated on K562 sensitive cells. Methyl 12α-[(2R or 2S) tetrahydro-2H-pyran-2-yloxy]-3-oxo-5ß-cholan-24-oate 9b has shown a good efficiency as a Pgp inhibitor and a low intrinsic toxicity. Therefore, this derivative constitutes a new lead compound which can be used as a starting point to improve the design of non-toxic Pgp modulators.
Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors , Daunorubicin/metabolism , Deoxycholic Acid/analogs & derivatives , Deoxycholic Acid/pharmacology , Doxorubicin/metabolism , ATP Binding Cassette Transporter, Subfamily B/antagonists & inhibitors , ATP Binding Cassette Transporter, Subfamily B/metabolism , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Deoxycholic Acid/chemistry , Drug Resistance, Multiple , Drug Resistance, Neoplasm , Humans , K562 CellsABSTRACT
A simple route for improving the potency of progesterone as a modulator of P-gp-mediated multidrug resistance was established by esterification or etherification of hydroxylated 5α/ß-pregnane-3,20-dione or 5ß-cholan-3-one precursors. X-ray crystallography of representative 7α-, 11α-, and 17α-(2'R/S)-O-tetrahydropyranyl ether diastereoisomers revealed different combinations of axial-equatorial configurations of the anomeric oxygen. Substantial stimulation of accumulation and chemosensitization was observed on K562/R7 erythroleukemia cells resistant to doxorubicin, especially using 7α,11α-O-disubstituted derivatives of 5α/ß-pregnane-3,20-dione, among which the 5ß-H-7α-benzoyloxy-11α-(2'R)-O-tetrahydropyranyl ether 22a revealed promising properties (accumulation index 2.9, IC50 0.5 µM versus 1.2 and 10.6 µM for progesterone), slightly overcoming those of verapamil and cyclosporin A. Several 7α,12α-O-disubstituted derivatives of 5ß-cholan-3-one proved even more active, especially the 7α-O-methoxymethyl-12α-benzoate 56 (accumulation index 3.8, IC50 0.2 µM). The panel of modulating effects from different O-substitutions at a same position suggests a structural influence of the substituent completing a simple protection against stimulating effects of hydroxyl groups on P-gp-mediated transport.
Subject(s)
ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors , Drug Resistance, Multiple/drug effects , Drug Resistance, Neoplasm/drug effects , Leukemia, Erythroblastic, Acute/drug therapy , Leukemia, Erythroblastic, Acute/metabolism , Progesterone/pharmacology , ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism , Cell Survival/drug effects , Crystallography, X-Ray , Humans , K562 Cells , Leukemia, Erythroblastic, Acute/pathology , Models, Molecular , Molecular Conformation , Progesterone/chemical synthesis , Progesterone/chemistry , Tumor Cells, CulturedABSTRACT
Bisphenol A (BPA), is one of the most abundant endocrine disruptors that are present in our environment, and has been repeatedly detected in most human biological samples. As it has been suggested that part of the BPA measured in human samples is due to contamination during samples collection or laboratory measurements, we have developed a specific radioimmunoassay for the measurement of BPA-glucuronide (BPA-G), the main endogenous metabolite of BPA in urine. We used a polyclonal anti-BPA antibody which has a 95% cross reactivity with BPA-G, and insignificant cross reactivity with most analogous BPA phenolic structures. To eliminate unconjugated BPA from urine samples, an extraction step with dichloromethane was required. The method proved to be valid, precise and accurate in the range of 0.05 µg/L to 5 µg/L. With this method, we measured BPA-G in 163 urine samples from a hospital population. We detected BPA-G in all samples, with mean values of 4.64 µg/L. In conclusion, the present radioimmunoassay is a useful tool for the screening of BPA exposure in human populations encompassing the problem of eventual contamination from laboratory manipulation.
Subject(s)
Benzhydryl Compounds/chemistry , Benzhydryl Compounds/urine , Endocrine Disruptors/chemistry , Endocrine Disruptors/urine , Glucuronides/chemistry , Phenols/chemistry , Phenols/urine , Urinalysis/methods , Environmental Exposure/analysis , Humans , Radioimmunoassay , Time FactorsABSTRACT
Bisphenol A (BPA) is widely used in the manufacturing of polycarbonate plastic food and drink packaging. Possessing a weak estrogenic activity, BPA is listed among a growing list of endocrine disrupting compounds. In this study, a polyclonal anti-BPA antibody was obtained by immunization with BPA-monocarboxymethylether covalently linked to BSA. The antibody demonstrates negligible cross-reactivity with most analogous BPA phenolic structures, and no cross-reactivity with endogenous steroids. An extraction step with ethyl acetate minimized matrix effects and allowed the BPA measurement in plasma and other biological samples. Recovery after loading test was 96 +/- 4% and dilution tests had a linear profile (r2 > 0.93). The limit of detection of the BPA RIA was 0.08 microg L(-1) with an IC50 of 1.25 microg L(-1). The intra- and inter-assay coefficients of variation were 5.6 and 8.6%, respectively at a BPA concentration of 0.7 microg L(-1) and 6.9 and 5.7% at a BPA concentration of 1.3 microg L(-1). A significant correlation was found between the values obtained by the RIA and HPLC-MS (r2 = 0.92) or HPLC coupled to a fluorescence detector (r2 = 0.80). In conclusion, we described a BPA-RIA that is a suitable tool for evaluating human exposure to BPA.
