Zhexue Wu

CYP2J2 and CYP2C19 Are the Major Enzymes Responsible for Metabolism of Albendazole and Fenbendazole in Human Liver Microsomes and Recombinant P450 Assay Systems

ABSTRACT Albendazole and fenbendazole are broad-spectrum anthelmintics that undergo extensive metabolism to form hydroxyl and sulfoxide metabolites. Although CYP3A and flavin-containing monooxygenase have been implicated in sulfoxide metabolite formation, the enzymes responsible for hydroxyl metabolite formation have not been identified. In this study, we used human liver microsomes and recombinant cytochrome P450s (P450s) to characterize the enzymes involved in the formation of hydroxyalbendazole and hydroxyfenbendazole from albendazole and fenbendazole, respectively. Of the 10 recombinant P450s, CYP2J2 and/or CYP2C19 was the predominant enzyme catalyzing the hydroxylation of albendazole and fenbendazole. Albendazole hydroxylation to hydroxyalbendazole is primarily mediated by CYP2J2 (0.34 μl/min/pmol P450, which is a rate 3.9- and 8.1-fold higher than the rates for CYP2C19 and CYP2E1, respectively), whereas CYP2C19 and CYP2J2 contributed to the formation of hydroxyfenbendazole from fenbendazole (2.68 and 1.94 μl/min/pmol P450 for CYP2C19 and CYP2J2, respectively, which are rates 11.7- and 8.4-fold higher than the rate for CYP2D6). Correlation analysis between the known P450 enzyme activities and the rate of hydroxyalbendazole and hydroxyfenbendazole formation in samples from 14 human liver microsomes showed that albendazole hydroxylation correlates with CYP2J2 activity and fenbendazole hydroxylation correlates with CYP2C19 and CYP2J2 activities. These findings were supported by a P450 isoform-selective inhibition study in human liver microsomes. In conclusion, our data for the first time suggest that albendazole hydroxylation is primarily catalyzed by CYP2J2, whereas fenbendazole hydroxylation is preferentially catalyzed by CYP2C19 and CYP2J2. The present data will be useful in understanding the pharmacokinetics and drug interactions of albendazole and fenbendazole in vivo.

Inhibition of cytochrome P450 2J2 by tanshinone IIA induces apoptotic cell death in hepatocellular carcinoma HepG2 cells.

Cytochrome P450 2J2 (CYP2J2) is highly expressed in human tumors and carcinoma cell lines, and has been implicated in the pathogenesis of human cancers. The aim of this study was to identify a compound that could inhibit the activity of CYP2J2, and to examine its anticancer activity. To identify CYP2J2 inhibitors, 10 terpenoids obtained from plants were screened using astemizole as a CYP2J2 probe substrate in human liver microsomes (HLMs). Of these, tanshinone IIA dose-dependently and non-competitively inhibited CYP2J2-mediated astemizole O-demethylation activity. Tanshinone IIA significantly decreased viability of human hepatoma HepG2 cells and SiHa cervical cancer cells; however, it was not cytotoxic against mouse hepatocytes. Furthermore, treatment of cells with tanshinone IIA significantly increased apoptotic cell death rate, as shown by the increase in Annexin V-stained cell populations, Bcl-2 associated X protein (Bax)/B-cell lymphoma 2 (Bcl-2) ratio, and poly (ADP-ribose) polymerase 1 (PARP-1) cleavage in HepG2 cells. Furthermore, the results of this study showed that tanshinone IIA significantly decreased HepG2 cell-based tumor growth in nude mice in a dose-dependent manner. On the other hand, the tanshinone IIA-induced apoptotic cell death rate was significantly attenuated by enhanced up-regulation of CYP2J2 expression. Thus, our data strongly suggest that tanshinone IIA exerts its anticancer effect by inhibiting CYP2J2 activity.

Potential of decursin to inhibit the human cytochrome P450 2J2 isoform.

CYP2J2 enzyme is highly expressed in human tumors and carcinoma cell lines, and epoxyeicosatrienoic acids, CYP2J2-mediated metabolites, have been implicated in the pathologic development of human cancers. To identify a CYP2J2 inhibitor, 50 natural products obtained from plants were screened using astemizole as a CYP2J2 probe substrate in human liver microsomes. Of these, decursin noncompetitively inhibited CYP2J2-mediated astemizole O-demethylation and terfenadine hydroxylation activities with Ki values of 8.34 and 15.8μM, respectively. It also showed cytotoxic effects against human hepatoma HepG2 cells in a dose-dependent manner while it did not show cytotoxicity against mouse hepatocytes. The present data suggest that decursin is a potential candidate for further evaluation for its CYP2J2 targeting anti-cancer activities. Studies are currently underway to test decursin as a potential therapeutic agent for cancer.

Identification of acetylshikonin as the novel CYP2J2 inhibitor with anti-cancer activity in HepG2 cells

BACKGROUND Acetylshikonin is one of the biologically active compounds derived from the root of Lithospermum erythrorhizon, a medicinal plant with anti-cancer and anti-inflammation activity. Although there have been a few previous reports demonstrating that acetylshikonin exerts anti-cancer activity in vitro and in vivo, it is still not clear what is the exact molecular target protein of acetylshikonin in cancer cells. PURPOSE The purpose of this study is to evaluate the inhibitory effect of acetylshikonin against CYP2J2 enzyme which is predominantly expressed in human tumor tissues and carcinoma cell lines. STUDY DESIGN The inhibitory effect of acetylshikonin on the activities of CYP2J2-mediated metabolism were investigated using human liver microsomes (HLMs), and its cytotoxicity against human hepatoma HepG2 cells was also evaluated. METHOD Astemizole, a representative CYP2J2 probe substrate, was incubated in HLMs in the presence or absence of acetylshikonin. After incubation, the samples were analyzed by liquid chromatography and triple quadrupole mass spectrometry. The anti-cancer activity of acetylshikonin was evaluated on human hepatocellular carcinoma HepG2 cells. WST-1, cell counting, and colony formation assays were further adopted for the estimation of the growth rate of HepG2 cells treated with acetylshikonin. RESULTS Acetylshikonin inhibited CYP2J2-mediated astemizole O-demethylation activity (Ki = 2.1µM) in a noncompetitive manner. The noncompetitive inhibitory effect of acetylshikonin on CYP2J2 enzyme was also demonstrated using this 3D structure, which showed different binding location of astemizole and acetylshikonin in CYP2J2 model. It showed cytotoxic effects against human hepatoma HepG2 cells (IC50 = 2μM). In addition, acetylshikonin treatment inhibited growth of human hepatocellular carcinoma HepG2 cells leading to apoptosis accompanied with p53, bax, and caspase3 activation as well as bcl2 down-regulation. CONCLUSION Taken together, our present study elucidates acetylshikonin displays the inhibitory effects against CYP2J2 in HLMs and anti-cancer activity in human hepatocellular carcinoma HepG2 cells.

Inhibitory Potential of Thelephoric Acid on CYP2J2 Activities in Human Liver Microsomes

Cytochrome P450 2J2 (CYP2J2) is an enzyme mainly found in human extrahepatic tissues, with predominant expression in the cardiovascular system. CYP2J2 plays important roles in the metabolism of endogenous metabolites and therapeutic drugs, such as arachidonic acid, astemizole, ebastine, and terfenadine. CYP2J2 is also overexpressed in human cancer tissues and cancer cell lines and may represent a potential target for therapy of human cancers. In this study, 10 natural products obtained from plants and microorganisms were screened as potential CYP2J2 inhibitors. Among them, thelephoric acid showed strong inhibition of astemizole O-demethylation activity (

In vitro metabolism of an estrogen-related receptor γ modulator, GSK5182, by human liver microsomes and recombinant cytochrome P450s.

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Lipidomic platform for structural identification of skin ceramides with α-hydroxyacyl chains

GSK5182 (4‐[(Z)‐1‐[4‐(2‐dimethylaminoethyloxy)phenyl]‐hydroxy‐2‐phenylpent‐1‐enyl]phenol) is a specific inverse agonist for estrogen‐related receptor γ, a member of the orphan nuclear receptor family that has important functions in development and homeostasis. This study was performed to elucidate the metabolites of GSK5182 and to characterize the enzymes involved in its metabolism. Incubation of human liver microsomes with GSK5182 in the presence of NADPH resulted in the formation of three metabolites, M1, M2 and M3. M1 and M3 were identified as N‐desmethyl‐GSK5182 and GSK5182 N‐oxide, respectively, on the basis of liquid chromatography‐tandem mass spectrometric (LC‐MS/MS) analysis. M2 was suggested to be hydroxy‐GSK5182 through interpretation of its MS/MS fragmentation pattern. In addition, the specific cytochrome P450 (P450) and flavin‐containing monooxygenase (FMO) isoforms responsible for GSK5182 oxidation to the three metabolites were identified using a combination of correlation analysis, chemical inhibition in human liver microsomes and metabolism by expressed recombinant P450 and FMO isoforms. GSK5182 N‐demethylation and hydroxylation is mainly mediated by CYP3A4, whereas FMO1 and FMO3 contribute to the formation of GSK5182 N‐oxide from GSK5182. The present data will be useful for understanding the pharmacokinetics and drug interactions of GSK5182 in vivo. Copyright

Danazol Inhibits Cytochrome P450 2J2 Activity in a Substrate-independent Manner

Skin ceramides are sphingolipids consisting of sphingoid bases, which are linked to fatty acids via an amide bond. Typical fatty acid acyl chains are composed of α-hydroxy fatty acid (A), esterified ω-hydroxy fatty acid (EO), non-hydroxy fatty acid (N), and ω-hydroxy fatty acid (O). We recently established a lipidomic platform to identify skin ceramides with non-hydroxyacyl chains using tandem mass spectrometry. We expanded our study to establish a lipidomic platform to identify skin ceramides with α-hydroxyacyl chains. Tandem mass spectrometry analysis of A-type ceramides using chip-based direct infusion nanoelectrospray-mass spectrometry showed the characteristic fragmentation pattern of both acyl and sphingoid units, which can be applied for structural identification of ceramides. Based on the tandem mass spectrometry fragmentation patterns of A-type ceramides, comprehensive fragmentation schemes were proposed. Our results may be useful for identifying A-type ceramides in the stratum corneum of human skin.

Mass Spectrometry-based Lipidomics and Its Application to Biomedical Research.

Cytochrome P450 2J2 (CYP2J2) is an enzyme responsible for the metabolism of endogenous substrates including arachidonic acid, as well as therapeutic drugs such as albendazole, astemizole, ebastine, and terfenadine. Selective inhibitors of CYP2J2 are essential for P450 reaction phenotyping studies. To find representative CYP2J2 index inhibitors, we evaluated the inhibitory potential of danazol, hydroxyebastine, telmisartan, and terfenadone against CYP2J2 activity for four representative CYP2J2 substrates (albendazole, astemizole, ebastine, and terfenadine) using recombinant CYP2J2. Of these four CYP2J2 inhibitors, danazol strongly inhibited CYP2J2-mediated albendazole, astemizole, ebastine, and terfenadine metabolism in a substrate-independent manner, with IC50 values of 0.05, 0.07, 0.18, and 0.34 μM, respectively. Danazol noncompetitively inhibited CYP2J2-mediated astemizole O-demethylation activities with a Ki value of 0.06 μM. Terfenadone strongly inhibited CYP2J2-mediated albendazole, astemizole, and terfenadine metabolism (IC50 < 0.21 μM), whereas it showed weak inhibition against CYP2J2-catalyzed ebastine hydroxylase activity (IC50 = 6.04 μM). Telmisartan had no inhibitory effect on CYP2J2-mediated ebastine and terfenadine hydroxylation (IC50 > 20 μM). Taken together, these data suggest that danazol may be used as a CYP2J2 index inhibitor in reaction phenotyping studies.

In vitro metabolism of obovatol and its effect on cytochrome P450 enzyme activities in human liver microsomes

Lipidomics, a branch of metabolomics, is the large-scale study of pathways and networks of all cellular lipids in biological systems such as cells, tissues or organisms. The recent advance in mass spectrometry technologies have enabled more comprehensive lipid profiling in the biological samples. In this review, we compared four representative lipid profiling technoligies including GC-MS, LC-MS, direct infusion-MS and imaging-MS. We also summarized representative lipid database, and further discussed the applications of lipidomics to the diagnostics of various diseases such as diabetes, obesity, hypertension, and Alzheimer diseases.