Prodrugging fungicidal amphotericin B significantly decreases its toxic effects.

Amphotericin B (AmB) is one of the most effective antifungal drugs, with a strong, dose-dependent activity against most Candida and Aspergillus species responsible for life-threatening infections. However, AmB is severely toxic, which hinders its broad use. In this proof-of-concept study, we demonstrate that prodrugging AmB considerably decreases AmB toxicity without affecting its fungicidal activity.

Benzo[]pyrene-Induced Genotoxicity in Rats Is Affected by Co-Exposure to Sudan I by Altering the Expression of Biotransformation Enzymes.

The environmental pollutant benzo[]pyrene (BaP) is a human carcinogen that reacts with DNA after metabolic activation catalysed by cytochromes P450 (CYP) 1A1 and 1B1 together with microsomal epoxide hydrolase. The azo dye Sudan I is a potent inducer of CYP1A1/2. Here, Wistar rats were either treated with single doses of BaP (150 mg/kg bw) or Sudan I (50 mg/kg bw) alone or with both compounds in combination to explore BaP-derived DNA adduct formation .

Photo-initiated crosslinking extends mapping of the protein-protein interface to membrane-embedded portions of cytochromes P450 2B4 and b₅.

Protein-protein interactions play a central role in the regulation of many biochemical processes (e.g. the system participating in enzyme catalysis).

Quantification of interactions between cytochrome P450 2B4 and cytochrome b5 in a functional membrane complex.

Objectives: The mammalian mixed function oxidase (MFO) system participates in hydroxylation of many hydrophobic endogenous compounds as well as xenobiotics such as drugs and carcinogens. This biotransformation system, located in a membrane of endoplasmic reticulum, consists of cytochrome P-450 (P450), NADPH:P450 oxidoreductase and a facultative component, cytochrome b5. The knowledge of the interactions among the individual components of the MFO system is essential to understand the relationships between the structure and function of this system that finally dictate a qualitative and quantitative pattern of produced metabolites (e.

The anticancer drug ellipticine activated with cytochrome P450 mediates DNA damage determining its pharmacological efficiencies: studies with rats, Hepatic Cytochrome P450 Reductase Null (HRN™) mice and pure enzymes.

Ellipticine is a DNA-damaging agent acting as a prodrug whose pharmacological efficiencies and genotoxic side effects are dictated by activation with cytochrome P450 (CYP). Over the last decade we have gained extensive experience in using pure enzymes and various animal models that helped to identify CYPs metabolizing ellipticine. In this review we focus on comparison between the in vitro and in vivo studies and show a necessity of both approaches to obtain valid information on CYP enzymes contributing to ellipticine metabolism.

Role of rat cytochromes P450 in the oxidation of 17α-ethinylestradiol.

17α-Ethinylestradiol (EE2) is an endocrine disruptor (ED) used as an ingredient of oral contraceptives. Rat hepatic microsomes metabolize EE2 to three products; two of them are hydroxylated EE2 derivatives. Of the hydroxylation reactions, 2-hydroxylation, is the major reaction.

Cytochrome b5 and epoxide hydrolase contribute to benzo[a]pyrene-DNA adduct formation catalyzed by cytochrome P450 1A1 under low NADPH:P450 oxidoreductase conditions.

In previous studies we had administered benzo[a]pyrene (BaP) to genetically engineered mice (HRN) which do not express NADPH:cytochrome P450 oxidoreductase (POR) in hepatocytes and observed higher DNA adduct levels in livers of these mice than in wild-type mice. To elucidate the reason for this unexpected finding we have used two different settings for in vitro incubations; hepatic microsomes from control and BaP-pretreated HRN mice and reconstituted systems with cytochrome P450 1A1 (CYP1A1), POR, cytochrome b5, and epoxide hydrolase (mEH) in different ratios. In microsomes from BaP-pretreated mice, in which Cyp1a1 was induced, higher levels of BaP metabolites were formed, mainly of BaP-7,8-dihydrodiol.

The effect of benzo[a]pyrene on metabolic activation of anticancer drug ellipticine in mice.

Objectives: The aim of this study was to investigate a role of cytochrome P450 (CYP) and peroxidase in ellipticine oxidative activation in two mouse strains differing in expression of NADPH:CYP reductase (POR) [the HRN (Hepatic Cytochrome P450 Reductase Null) mice, in which POR is deleted in hepatocytes and its wild-type (WT) counterpart], and in levels of CYP1A1/2 and cytochrome b5 that were modulated by treatment of these mouse models with a CYP1A inducer, benzo[a]pyrene (BaP).

Methods: Ellipticine-DNA adducts were detected by 32P-postlabeling. HPLC was employed for the separation and characterization of ellipticine metabolites.

Cytochrome b5 increases cytochrome P450 3A4-mediated activation of anticancer drug ellipticine to 13-hydroxyellipticine whose covalent binding to DNA is elevated by sulfotransferases and N,O-acetyltransferases.

The antineoplastic alkaloid ellipticine is a prodrug, whose pharmacological efficiency is dependent on its cytochrome P450 (P450)- and/or peroxidase-mediated activation in target tissues. The P450 3A4 enzyme oxidizes ellipticine to five metabolites, mainly to 13-hydroxy- and 12-hydroxyellipticine, the metabolites responsible for the formation of ellipticine-13-ylium and ellipticine-12-ylium ions that generate covalent DNA adducts. Cytochrome b(5) alters the ratio of ellipticine metabolites formed by P450 3A4.