Publications

• Expression and Functional Characterization of Breast Cancer-Associated Cytochrome P450 4Z1 in Saccharomyces cerevisiae.

  McDonald M.G., Ray S., Amorosi C.J., Sitko K.A., Kowalski J.P., Paco L., Nath A., Gallis B., Totah R.A., Dunham M.J., Fowler D.M., Rettie A.E.

  CYP4Z1 is an "orphan" cytochrome P450 (P450) enzyme that has provoked interest because of its hypothesized role in breast cancer through formation of the signaling molecule 20-hydroxyeicosatetraenoic acid (20-HETE). We expressed human CYP4Z1 in <i>Saccharomyces cerevisiae</i> and evaluated its cat ... >> More

  CYP4Z1 is an "orphan" cytochrome P450 (P450) enzyme that has provoked interest because of its hypothesized role in breast cancer through formation of the signaling molecule 20-hydroxyeicosatetraenoic acid (20-HETE). We expressed human CYP4Z1 in <i>Saccharomyces cerevisiae</i> and evaluated its catalytic capabilities toward arachidonic and lauric acids (AA and LA). Specific and sensitive mass spectrometry assays enabled discrimination of the regioselectivity of hydroxylation of these two fatty acids. CYP4Z1 generated 7-, 8-, 9-, 10-, and 11-hydroxy LA, whereas the 12-hydroxy metabolite was not detected. HET0016, the prototypic CYP4 inhibitor, only weakly inhibited laurate metabolite formation (IC₅₀ ∼15 <i>μ</i>M). CYP4Z1 preferentially oxidized AA to the 14(S),15(R)-epoxide with high regioselectivity and stereoselectivity, a reaction that was also insensitive to HET0016, but neither 20-HETE nor 20-carboxy-AA were detectable metabolites. Docking of LA and AA into a CYP4Z1 homology model was consistent with this preference for internal fatty acid oxidation. Thus, human CYP4Z1 has an inhibitor profile and product regioselectivity distinct from most other CYP4 enzymes, consistent with CYP4Z1's lack of a covalently linked heme. These data suggest that, if CYP4Z1 modulates breast cancer progression, it does so by a mechanism other than direct production of 20-HETE. << Less

  Drug Metab. Dispos. 45:1364-1371(2017) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.

• Stereoselective epoxidation of the last double bond of polyunsaturated fatty acids by human cytochromes P450.

  Lucas D., Goulitquer S., Marienhagen J., Fer M., Dreano Y., Schwaneberg U., Amet Y., Corcos L.

  Cytochromes P450 (CYPs) metabolize polyunsaturated long-chain fatty acids (PUFA-LC) to several classes of oxygenated metabolites. Through use of human recombinant CYPs, we recently showed that CYP1A1, -2C19, -2D6, -2E1, and -3A4 are mainly hydroxylases, whereas CYP1A2, -2C8, -2C9, and -2J2 are mai ... >> More

  Cytochromes P450 (CYPs) metabolize polyunsaturated long-chain fatty acids (PUFA-LC) to several classes of oxygenated metabolites. Through use of human recombinant CYPs, we recently showed that CYP1A1, -2C19, -2D6, -2E1, and -3A4 are mainly hydroxylases, whereas CYP1A2, -2C8, -2C9, and -2J2 are mainly epoxygenases of arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), respectively. It is worth noting that the last double bond of these PUFAs, i.e., omega6 in AA or omega3 in EPA and DHA, respectively, was preferentially epoxidized. In this study, we have characterized the stereoselectivity of this epoxidation reaction by comparison with the PUFA-LC epoxide stereoisomers obtained from the enantioselective bacterial CYP102A1 F87V. The stereoselectivity of the epoxidation of the last olefin of AA (omega6), EPA (omega3), or DHA (omega3) differed between the CYP isoforms but was similar for EPA and DHA. These data give additional insight into the PUFA-LC epoxide enantiomers generated by the hepatic CYPs. << Less

  J. Lipid Res. 51:1125-1133(2010) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.

• Analysis of epoxyeicosatrienoic acids by chiral liquid chromatography/electron capture atmospheric pressure chemical ionization mass spectrometry using [13C]-analog internal standards.

  Mesaros C., Lee S.H., Blair I.A.

  The metabolism of arachidonic acid (AA) to epoxyeicosatrienoic acids (EETs) is thought to be mediated primarily by the cytochromes P450 (P450s) from the 2 family (2C9, 2C19, 2D6, and 2J2). In contrast, P450s of the 4 family are primarily involved in omega oxidation of AA (4A11 and 4A22). The abili ... >> More

  The metabolism of arachidonic acid (AA) to epoxyeicosatrienoic acids (EETs) is thought to be mediated primarily by the cytochromes P450 (P450s) from the 2 family (2C9, 2C19, 2D6, and 2J2). In contrast, P450s of the 4 family are primarily involved in omega oxidation of AA (4A11 and 4A22). The ability to determine enantioselective formation of the regioisomeric EETs is important in order to establish their potential biological activities and to asses which P450 isoforms are involved in their formation. It has been extremely difficult to analyze individual EET enantiomers in biological fluids because they are present in only trace amounts and they are extremely difficult to separate from each other. In addition, the deuterium-labeled internal standards that are commonly used for stable isotope dilution liquid chromatography/mass spectrometry (LC/MS) analyses have different LC retention times when compared with the corresponding protium forms. Therefore, quantification by LC/MS-based methodology can be compromised by differential suppression of ionization of the closely eluting isomers. We report the preparation of [(13)C(20)]-EET analog internal standards and the use of a validated high-sensitivity chiral LC/electron capture atmospheric pressure chemical ionization (ECAPCI)-MS method for the trace analysis of endogenous EETs as their pentafluorobenzyl (PFB) ester derivatives. The assay was then used to show the exquisite enantioselectivity of P4502C19-, P4502D6-, P4501A1-, and P4501B1-mediated conversion of AA into EETs and to quantify the enantioselective formation of EETs produced by AA metabolism in a mouse epithelial hepatoma (Hepa) cell line. << Less

  Rapid Commun. Mass Spectrom. 24:3237-3247(2010) [PubMed] [EuropePMC]

  This publication is cited by 4 other entries.

• Molecular cloning and expression of CYP2J2, a human cytochrome P450 arachidonic acid epoxygenase highly expressed in heart.

  Wu S., Moomaw C.R., Tomer K.B., Falck J.R., Zeldin D.C.

  A cDNA encoding a human cytochrome P450 arachidonic acid epoxygenase was isolated from a human liver cDNA library. Sequence analysis revealed that this 1,876-base pair cDNA contained an open reading frame and encoded a new 502-amino acid protein designated CYP2J2. Blot hybridization analysis of RN ... >> More

  A cDNA encoding a human cytochrome P450 arachidonic acid epoxygenase was isolated from a human liver cDNA library. Sequence analysis revealed that this 1,876-base pair cDNA contained an open reading frame and encoded a new 502-amino acid protein designated CYP2J2. Blot hybridization analysis of RNA prepared from human tissues revealed that CYP2J2 was highly expressed in the heart. Recombinant CYP2J2 protein was prepared using the baculovirus expression system and purified to near electrophoretic homogeneity. The enzyme metabolized arachidonic acid predominantly via olefin epoxidation to all four regioisomeric cis-epoxyeicosatrienoic acids (catalytic turnover 65 pmol of product formed/nmol of cytochrome P450/min at 30 degrees C). Epoxidation of arachidonic acid by CYP2J2 at the 14,15-olefin was highly enantioselective for (14R, 15S)-epoxyeicosatrienoic acid (76% optical purity). Immunoblotting of microsomal fractions prepared from human tissues using a polyclonal antibody raised against the recombinant hemoprotein confirmed primary expression of CYP2J2 protein in human heart. The in vivo significance of CYP2J2 was suggested by documenting the presence of epoxyeicosatrienoic acids in the human heart using gas chromatography/mass spectroscopy. Importantly, the chirality of CYP2J2 products matched that of the epoxyeicosatrienoic acid enantiomers present, in vivo, in human heart. We propose that CYP2J2 is one of the enzymes responsible for epoxidation of endogenous arachidonic acid pools in human heart and that epoxyeicosatrienoic acids may, therefore, play important functional roles in cardiac physiology. << Less

  J. Biol. Chem. 271:3460-3468(1996) [PubMed] [EuropePMC]

  This publication is cited by 6 other entries.

• CYP2C40, a unique arachidonic acid 16-hydroxylase, is the major CYP2C in murine intestinal tract.

  Tsao C.C., Foley J., Coulter S.J., Maronpot R., Zeldin D.C., Goldstein J.A.

  We recently identified five different murine CYP2C cDNAs from a murine cDNA library. When expressed in a bacterial cDNA expression system, all five recombinant proteins metabolized arachidonic acid but produced distinctly different profiles. In addition, some CYP2C mRNAs were found in extrahepatic ... >> More

  We recently identified five different murine CYP2C cDNAs from a murine cDNA library. When expressed in a bacterial cDNA expression system, all five recombinant proteins metabolized arachidonic acid but produced distinctly different profiles. In addition, some CYP2C mRNAs were found in extrahepatic tissues, as well as in liver. Immunoblots with an antibody raised against recombinant CYP2C38, which recognizes all five murine CYP2Cs, demonstrated that among extrahepatic tissues, colon and cecum contained the highest amount of CYP2Cs. The highest concentration of CYP2Cs occurred in cecum and colon (cecum >/= proximal colon >> distal colon), with lower levels in duodenum, jejunum, and ileum. Immunohistochemical studies revealed that CYP2Cs were localized principally in epithelial cells and autonomic ganglia in gut and colon. Polymerase chain reaction amplification of reverse-transcribed mRNA using murine CYP2C-specific primers followed by cloning and sequencing identified CYP2C40 as the major CYP2C isoform expressed in murine intestinal tract. Recombinant CYP2C40 metabolized arachidonic acid in a regio- and stereospecific manner to 16(R)-HETE (hydroxyeicosatetraenoic acid) as the major product. To our knowledge, CYP2C40 is the first enzyme known to produce primarily 16-HETE. We conclude that CYP2C40 is one of the major cytochrome P450 proteins in the mouse intestinal tract. In the light of vasoactive and anti-neutrophilic effects of 16-HETE, we hypothesize that CYP2C40 may play an important role in endogenous biological functions in intestine. << Less

  Mol. Pharmacol. 58:279-287(2000) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• The kidney cytochrome P-450 2C23 arachidonic acid epoxygenase is upregulated during dietary salt loading.

  Holla V.R., Makita K., Zaphiropoulos P.G., Capdevila J.H.

  Excess dietary salt intake induces the activity of the kidney arachidonate epoxygenase and markedly increases the urinary excretion of its metabolites. The epoxyeicosatrienoic acids, products of the kidney P-450 arachidonate epoxygenase, inhibit distal nephron Na(+) reabsorption. Nucleic acid hybr ... >> More

  Excess dietary salt intake induces the activity of the kidney arachidonate epoxygenase and markedly increases the urinary excretion of its metabolites. The epoxyeicosatrienoic acids, products of the kidney P-450 arachidonate epoxygenase, inhibit distal nephron Na(+) reabsorption. Nucleic acid hybridization studies demonstrated the expression of P-450s 2C23, 2C24, and 2C11 as the predominant kidney 2C isoforms and the lack of significant dietary salt-dependent transcriptional regulation of these proteins. Recombinant P-450s 2C11, 2C23, and 2C24 catalyze arachidonate metabolism to mixtures of epoxy- and monohydroxylated acids. Whereas the arachidonate 11,12-olefin was the preferred target for epoxidation by P-450 2C23 (57% of total products), P-450s 2C11 and 2C24 epoxidized the 11,12-olefins and 14,15-olefins with nearly equal efficiency. Stereochemical comparisons demonstrated that the regiochemical and enantiofacial selectivity of P-450 2C23 matched that of the kidney microsomal epoxygenase and that excess dietary salt does not alter the regiochemical or stereochemical selectivity of the kidney arachidonate epoxygenase. Inhibition and immunoelectrophoresis experiments using antibodies raised against recombinant P-450s 2C11 and 2C23 demonstrated that P-450 2C23 is the major 2C arachidonic acid epoxygenase in the rat kidney and the renal P-450 isoform regulated by excess dietary salt intake. << Less

  J. Clin. Invest. 104:751-760(1999) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.

• Molecular cloning, expression and characterization of an endogenous human cytochrome P450 arachidonic acid epoxygenase isoform.

  Zeldin D.C., DuBois R.N., Falck J.R., Capdevila J.H.

  A cDNA containing an open reading frame coding for a human cytochrome P450 arachidonic acid epoxygenase was isolated from a male human kidney cDNA library. Sequence analysis showed that, with few exceptions, this cDNA was nearly identical to the published sequence for human liver Cyp 2C8 (S. T. Ok ... >> More

  A cDNA containing an open reading frame coding for a human cytochrome P450 arachidonic acid epoxygenase was isolated from a male human kidney cDNA library. Sequence analysis showed that, with few exceptions, this cDNA was nearly identical to the published sequence for human liver Cyp 2C8 (S. T. Okino et al., 1987, J. Biol. Chem. 262, 16072-16079) and encoded a polypeptide of 490 amino acids. Nucleic acid hybridization indicated that: (a) Cyp 2C8 and 2C10 were expressed at comparable levels in the human liver and (b) compared to Cyp 2C10, the steady state concentrations of Cyp 2C8 transcripts in the human kidney were substantially lower. The kidney 2C8 cDNA was cloned into a pBlue BacIII vector, expressed using a baculovirus/Sf9 insect cell system, and the recombinant Cyp 2C8 protein was purified by a combination of hydrophobic and hydroxylapatite chromatography. Purified recombinant Cyp 2C8 and 2C10 were reconstituted in the presence of NADPH and NADPH-cytochrome P450 reductase and shown to metabolize arachidonic via olefin epoxidation with both proteins generating, almost exclusively, epoxygenase-derived products (94 and 90% of total products, respectively). Catalytic turnover (1.05 and 0.75 nmol of product/nmol of hemoprotein/min at 30 degrees C for Cyp 2C8 and 2C10, respectively) was inhibited by the addition of purified cytochrome b5. Metabolism by recombinant 2C8 was both regio- and enantioselective for 11(R), 12(S)- and 14(R), 15(S)-epoxyeicosatrienoic acids (82% optical purity, each). Compared to Cyp 2C8, arachidonic acid epoxidation by Cyp 2C10 was less regio- and stereo-selective and generated mixtures of 8(S), 9(R)-, 11(S), 12(R)-, and 14(R), 15(S)-epoxyeicosatrienoic acids (with optical purities of 66, 69, 63%, respectively). Importantly, recombinant Cyp 2C8 and 2C10 epoxidized the arachidonic acid 11, 12-olefin with opposite enantiofacial selectivities. Only for Cyp 2C8 did the chirality of the products match that of the enantiomers present, in vivo, in human kidney cortex (A. Karara et al., 1990, FEBS Lett. 268, 227-230). Hence, we propose that Cyp 2C8 is one of the human cytochrome P450 isoforms responsible for the metabolism of endogenous arachidonic acid pools. << Less

  Arch. Biochem. Biophys. 322:76-86(1995) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.