Lawrence J Marnett

Gateway-Vanderbilt Cancer Treatment Center, Clarksville, Tennessee, United States

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Publications (545)2767.6 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A polypharmacologic approach to prostanoid based anti-inflammatory therapeutics was undertaken in order to exploit both the anti- and proinflammatory properties attributed to the various prostanoid receptors. Multitargeting of selected prostanoid receptors yielded a prototype compound, compound 1 (AGN 211377), that antagonizes prostaglandin D2 receptors DP1 (49) and DP2 (558), prostaglandin E2 receptors EP1 (266) and EP4 (117), prostaglandin F2α receptor (61), and thromboxane A2 receptor (TP) (11) while sparing EP2, EP3, and prostaglandin I2 receptors (IP); Kb values (in nanomoles) are given in parentheses. Compound 1 evoked a pronounced inhibition of cytokine/chemokine secretion from lipopolysaccharide or TNF-α stimulated primary human macrophages. These cytokine/chemokines included cluster of designation 40 receptor (CD40), epithelial-derived neutrophil-activating protein 78 (ENA-78), granulocyte colony stimulating factor (G-CSF), granulocyte macrophage colony stimulating factor (GM-CSF), IL-8, IL-18, monocyte chemotactic protein-1 (CCL2) (MCP-1), tissue plasminogen activator inhibitor (PAI-1), and regulated on activation, normal T cell expressed and secreted. In contrast, the inhibitory effects of most antagonists selective for a single receptor were modest or absent, and selective EP2 receptor blockade increased cytokine release in some instances. Compound 1 also showed clear superiority to the cyclooxygenase inhibitors diclofenac and rofecoxib. These findings reveal that blockade of multiple prostanoid receptors, with absent antagonism of EP2 and IP, may provide more effective anti-inflammatory activity than global suppression of prostanoid synthesis or highly selective prostanoid receptor blockade. These investigations demonstrate the first working example of prostanoid receptor polypharmacology for potentially safer and more effective anti-inflammatory therapeutics by blocking multiple proinflammatory receptors while sparing those with anti-inflammatory activity.-Wang, J. W., Woodward, D. F., Martos, J. L., Cornell, C. L., Carling, R. W., Kingsley, P. J., Marnett, L. J. Multitargeting of selected prostanoid receptors provides agents with enhanced anti-inflammatory activity in macrophages.
    The FASEB Journal 09/2015; DOI:10.1096/fj.15-275610 · 5.04 Impact Factor
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    ABSTRACT: Cyclooxygenase-2 (COX-2) oxygenates arachidonic acid (AA) and its ester analog, 2-arachidonoylglycerol (2-AG), to prostaglandins (PGs) and prostaglandin glyceryl esters (PG-Gs), respectively. Although the efficiency of oxygenation of these substrates by COX-2 in vitro is similar, cellular biosynthesis of PGs far exceeds that of PG-Gs. Evidence that the COX enzymes are functional heterodimers suggests that competitive interaction of AA and 2-AG at the allosteric site of COX-2 might result in differential regulation of the oxygenation of the two substrates when both are present. Modulation of AA levels in RAW264.7 macrophages uncovered an inverse correlation between cellular AA levels and PG-G biosynthesis. In vitro kinetic analysis using purified protein demonstrated that the inhibition of 2-AG oxygenation by high concentrations of AA far exceeded the inhibition of AA oxygenation by high concentrations of 2-AG. An unbiased systems-based mechanistic model of the kinetic data revealed that binding of AA or 2-AG at the allosteric site of COX-2 results in a decreased catalytic efficiency of the enzyme toward 2-AG, whereas 2-AG binding at the allosteric site increases COX-2's efficiency toward AA. The results suggest that substrates interact with COX-2 via multiple potential complexes involving binding to both the catalytic and allosteric sites. Competition between AA and 2-AG for these sites, combined with differential allosteric modulation, gives rise to a complex interplay between the substrates, leading to preferential oxygenation of AA.
    Proceedings of the National Academy of Sciences 09/2015; DOI:10.1073/pnas.1507307112 · 9.67 Impact Factor
  • Clinical Cancer Research 08/2015; 21(16 Supplement):POSTER-BIOL-1350-POSTER-BIOL-1350. DOI:10.1158/1557-3265.OVCASYMP14-POSTER-BIOL-1350 · 8.72 Impact Factor
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  • Cancer Research 08/2015; 75(15 Supplement):2068-2068. DOI:10.1158/1538-7445.AM2015-2068 · 9.33 Impact Factor
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    ABSTRACT: Carbaboranes are increasingly studied as pharmacophores, particularly as replacements for aromatic systems. However, especially ortho-carbaborane is prone to degradation of the cluster, which hampers biological application. This study demonstrates that deboronation of the cluster may not only lead to a more active analogue, but can also improve the solubility and stability of a carbaborane-containing inhibitor. Notably, introduction of a nido-dicarbaborate cluster into the cyclooxygenase (COX) inhibitor indomethacin results in remarkably increased inhibitory potency and selectivity for COX-2 relative to the respective phenyl analogue. The first crystal structure of a carbaborane-containing inhibitor bound to COX-2 further reveals a novel binding mode for the inhibitor that is strikingly different from that of indomethacin. These results indicate that nido-dicarbaborate is a promising pharmacophore that exhibits properties which are also highly beneficial for its introduction into other inhibitor classes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    ChemMedChem 06/2015; DOI:10.1002/cmdc.201500199 · 2.97 Impact Factor
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    ABSTRACT: Background: In aggregate, livers donated after circulatory death (DCD) provide lower rates of graft and patient survival compared to brain dead donors (DBD). A method to identify DCD livers likely to perform well would lead to better decision-making regarding which livers to use and which to discard and is an important unmet clinical need. We hypothesized that the ischemic time between extubation and cold perfusion in the donor leads to immediate and unique biochemical and molecular changes that could be used to predict subsequent function. Methods: Biopsies from normal perfused liver, immediately after cold perfusion during DCD or DBD liver procurement, and during subsequent cold storage were analyzed and compared. Biochemical analysis included adenosine triphosphate (ATP), adenosine diphosphate, adenosine monophosphate, hypoxanthine, xanthine, inosine, nicotinamide adenine dinucleotide, and flavin adenine dinucleotide. Levels of these metabolites were compared to peak posttransplant aspartate aminotransferase as a marker of ischemic injury. Molecular analysis was performed by transcriptional profiling using high throughput sequencing. Results: Immediately after cold perfusion in the donor, biochemical analysis revealed lower levels of ATP and adenosine diphosphate in DCD versus DBD liver samples (P < 0.01 in both cases). The ATP levels showed high negative correlation with peak aspartate aminotransferase levels in recipients (P = 0.029). Four hundred seventy genes showed differential expression in DCD but not DBD samples immediately after cold perfusion compared with normal liver samples. Upregulated genes function in inflammation and immunity, whereas downregulated genes function in translation. During cold storage, samples were transcriptionally inactive with no consistent changes in messenger RNA expression. Conclusion: The ATP content of liver samples taken immediately postperfusion correlates with ischemic injury. Transcriptional profiling identifies biological process that may be relevant for enhancing function in DCD liver transplantation. Transcriptional inactivity of cold stored samples suggests messenger RNA levels over time are unlikely to provide prognostic data.
    06/2015; 1(5):1-9. DOI:10.1097/TXD.0000000000000527
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    ABSTRACT: Cyclooxygenase-2 (COX-2) is a promising target for the imaging of cancer in a range of diagnostic and therapeutic settings. We report a near-infrared COX-2-targeted probe, fluorocoxib C (FC), for visualization of solid tumors by optical imaging. FC exhibits selective and potent COX-2 inhibition in both purified protein and human cancercell lines. In vivo optical imaging shows selective accumulation of FC in COX-2-overexpressing human tumor xenografts [1483 head and neck squamous cell carcinoma (HNSCC)] implanted in nude mice, while minimal uptake is detectable in COX-2-negative tumor xenografts (HCT116)or 1483 HNSCC xenografts preblocked with the COX-2-selective inhibitor celecoxib. Time course imaging studies conducted from 3 h to 7-day post-FC injection revealed a marked reduction in nonspecific fluorescent signals with retention of fluorescence in 1483 HNSCC tumors. Thus, use of FC in a delayed imaging protocol offers an approach to improve imaging signal-to-noise that should improve cancer detection in multiple preclinical and clinical settings.
    Journal of Biomedical Optics 05/2015; 20(5):050502. DOI:10.1117/1.JBO.20.5.050502 · 2.86 Impact Factor
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    ABSTRACT: Cyclooxygenase-1 (COX-1) is implicated in ovarian cancer. However, patterns of COX expression and function have been unclear and controversial. In this report, patterns of COX-1 and COX-2 gene expression were obtained from RNA-seq data through The Cancer Genome Atlas. Our analysis revealed markedly higher COX-1 mRNA expression than COX-2 in high-grade serous ovarian cancers (HGSOC) and higher COX-1 expression in HGSOC tumors than 10 other tumor types. High microarray. In contrast, lower or similar expression of COX-1 compared to COX-2 was observed in endometrioid, mucinous and clear cell tumors. Stable COX-1 knockdown in HGSOC-representative OVCAR-3 ovarian cancer cells reduced gene expression in multiple pro-tumorigenic pathways. Functional cell viability, clonogenicity, and migration/invasion assays were consistent with transcriptomic changes. These effects were reversed by stable over-expression of COX-1 in SKOV-3 cells. Our results demonstrate a distinct pattern of COX-1 over-expression in HGSOC tumors and strong association of COX-1 with multiple pro-tumorigenic pathways in ovarian cancer cells. cancer and support further development of methods to selectively target COX-1 in the management of HGSOC tumors.
    Oncotarget 05/2015; 6(25). DOI:10.18632/oncotarget.3860 · 6.36 Impact Factor
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    ABSTRACT: We report the design and synthesis of an activatable molecular imaging probe to detect hypoxia in mouse models of retinal vascular diseases. Hypoxia of the retina has been associated with the initiation and progression of blinding retinal vascular diseases including age-related macular degeneration, diabetic retinopathy, and retinopathy of prematurity. In vivo retinal imaging of hypoxia may be useful for early detection and timely treatment of retinal diseases. To achieve this goal, we synthesized HYPOX-3, a near-infrared (NIR) imaging agent coupled to a dark quencher, Black Hole Quencher 3 (BHQ3), which has been previously reported to contain a hypoxia-sensitive cleavable azo-bond. HYPOX-3 was cleaved in hypoxic retinal cell culture and animal models, enabling detection of hypoxia with high signal-to-noise ratios without acute toxicity. HYPOX-3 fluorescences in hypoxic cells and tissues and was undetectable under normoxia. These imaging agents are promising candidates for imaging retinal hypoxia in preclinical disease models and patients.
    ACS Medicinal Chemistry Letters 04/2015; 6(4):445-9. DOI:10.1021/ml5005206 · 3.12 Impact Factor
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    ABSTRACT: Etheno DNA adducts are a prevalent type of DNA damage caused by vinyl chloride (VC) exposure and oxidative stress. Etheno adducts are mutagenic and may contribute to the initiation of several pathologies; thus, elucidating the pathways by which they induce cellular transformation is critical. Although N(2),3-ethenoguanine (N(2),3-εG) is the most abundant etheno adduct, its biological consequences have not been well characterized in cells due to its labile glycosidic bond. Here, a stabilized 2'-fluoro-2'-deoxyribose analog of N(2),3-εG was used to quantify directly its genotoxicity and mutagenicity. A multiplex method involving next-generation sequencing enabled a large-scale in vivo analysis, in which both N(2),3-εG and its isomer 1,N(2)-ethenoguanine (1,N(2)-εG) were evaluated in various repair and replication backgrounds. We found that N(2),3-εG potently induces G to A transitions, the same mutation previously observed in VC-associated tumors. By contrast, 1,N(2)-εG induces various substitutions and frameshifts. We also found that N(2),3-εG is the only etheno lesion that cannot be repaired by AlkB, which partially explains its persistence. Both εG lesions are strong replication blocks and DinB, a translesion polymerase, facilitates the mutagenic bypass of both lesions. Collectively, our results indicate that N(2),3-εG is a biologically important lesion and may have a functional role in VC-induced or inflammation-driven carcinogenesis. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.
    Nucleic Acids Research 04/2015; 43(11). DOI:10.1093/nar/gkv243 · 9.11 Impact Factor
  • Gastroenterology 04/2015; 148(4):S-80. DOI:10.1016/S0016-5085(15)30280-8 · 16.72 Impact Factor
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    ABSTRACT: Cyclooxygenase enzymes (COX-1 and COX-2) catalyze the conversion of arachidonic acid (AA) to prostaglandin (PG)G2. The inhibitory activity of rapid, reversible COX inhibitors (ibuprofen, naproxen, mefenamic acid, and lumiracoxib) demonstrated a significant increase in potency and time-dependence of inhibition against double tryptophan mCOX-2 mutants at the 89/90 and 89/119 positions. In contrast, the slow, time-dependent COX inhibitors (diclofenac, indomethacin, and flurbiprofen) were unaffected by those mutations. Further mutagenesis studies suggested that mutation at position 89 was principally responsible for the changes in inhibitory potency of rapid, reversible inhibitors, while mutation at position 90 may exert some effect on the potency of COX-2-selective diarylheterocycle inhibitors; no effect was observed with mutation at position 119. Several crystal structures with or without NSAIDs indicated that placement of a bulky residue at position 89 caused a closure of a gap at the lobby, and alteration of histidine to tryptophan at position 90 changed the electrostatic profile of the side-pocket of COX-2. Thus, these two residues, especially Val-89 at the lobby region, are crucial for the entrance and exit of some NSAIDs from the COX active site. Copyright © 2015, The American Society for Biochemistry and Molecular Biology.
    Journal of Biological Chemistry 03/2015; 290(20). DOI:10.1074/jbc.M114.635987 · 4.57 Impact Factor
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    ABSTRACT: Products of oxidative damage to lipids include 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE), both of which are cytotoxic electrophiles. ONE reacts more rapidly with nucleophilic amino acid side chains, resulting in covalent protein adducts, including residue-residue cross-links. Previously, we demonstrated that peptidylprolyl cis/trans isomerase A1 (Pin1) was highly susceptible to adduction by HNE and that the catalytic cysteine (Cys113) was the preferential site of modification. Here, we show that ONE also preferentially adducts Pin1 at the catalytic Cys, but results in a profoundly different modification. Results from experiments using purified Pin1 incubated with ONE revealed the principal product to be a Cys-Lys pyrrole-containing cross-link between the side chains of Cys113 and Lys117. In vitro competition assays between HNE and ONE demonstrate that ONE reacts more rapidly than HNE with Cys113. Exposure of RKO cells to alkynyl-ONE (aONE) followed by copper-mediated click chemistry and streptavidin purification revealed that Pin1 is also modified by ONE in cells. Analysis of the Pin1 crystal structure reveals that Cys113 and Lys117 are oriented toward each other in the active site, facilitating formation of an ONE cross-link.
    Chemical Research in Toxicology 03/2015; 28(4). DOI:10.1021/acs.chemrestox.5b00038 · 3.53 Impact Factor
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    ABSTRACT: Non-melanoma skin cancer (NMSC) is the most common form of cancer in the US and its incidence is increasing. The current standard of care is visual inspection by physicians and/or dermatologists, followed by skin biopsy and pathologic confirmation. We have investigated the use of in vivo fluorescence imaging using fluorocoxib A as a molecular probe for early detection and assessment of skin tumors in mouse models of NMSC. Fluorocoxib A targets the cyclooxygenase-2 (COX-2) enzyme that is preferentially expressed by inflamed and tumor tissue, and therefore has potential to be an effective broadly active molecular biomarker for cancer detection. We tested the sensitivity of fluorocoxib A in a BCC allograft SCID hairless mouse model using a wide-field fluorescence imaging system. Subcutaneous allografts comprised of 1000 BCC cells were detectable above background. These BCC allograft mice were imaged over time and a linear correlation (R(2) = 0.8) between tumor volume and fluorocoxib A signal levels was observed. We also tested fluorocoxib A in a genetically engineered spontaneous BCC mouse model (Ptch1(+/-) K14-Cre-ER2 p53(fl/fl)), where sequential imaging of the same animals over time demonstrated that early, microscopic lesions (100 μm size) developed into visible macroscopic tumor masses over 11 to 17 days. Overall, for macroscopic tumors, the sensitivity was 88% and the specificity was 100%. For microscopic tumors, the sensitivity was 85% and specificity was 56%. These results demonstrate the potential of fluorocoxib A as an in vivo imaging agent for early detection, margin delineation and guided biopsies of NMSCs. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    Neoplasia (New York, N.Y.) 02/2015; 146(2). DOI:10.1016/j.neo.2014.12.009 · 4.25 Impact Factor
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    ABSTRACT: Cyclooxygenase-2 (COX-2) oxygenates arachidonic acid (AA) and the endocannabinoids, 2-arachidonoylglycerol (2-AG) and arachidonylethanolamide, to prostaglandins, prostaglandin glyceryl esters, and prostaglandin ethanolamides, respectively. A structural homodimer, COX-2 acts as a conformational heterodimer with a catalytic and an allosteric monomer. Prior studies have demonstrated substrate-selective negative allosteric regulation of 2-AG oxygenation. Here we describe AM-8138 (13(S)-methylarachidonic acid), a substrate-selective allosteric potentiator that augments 2-AG oxygenation by up to 3.5-fold with no effect on AA oxygenation. In the crystal structure of an AM-8138:COX-2 complex, AM-8138 adopts a conformation similar to an unproductive conformation of AA in the substrate binding site. Kinetic analysis suggests that binding of AM-8138 to the allosteric monomer of COX-2 increases 2-AG oxygenation by increasing kcat, and preventing inhibitory binding of 2-AG. AM-8138 restored the activity of COX-2 mutants that exhibited very poor 2-AG oxygenating activity and increased the activity of COX-1 toward 2-AG. Competition of AM-8138 for the allosteric site prevented the inhibition of COX-2-dependent 2-AG oxygenation by substrate-selective inhibitors and blocked the inhibition of AA or 2-AG oxygenation by nonselective time-dependent inhibitors. AM-8138 selectively enhanced 2-AG oxygenation in intact RAW264.7 macrophage-like cells. Thus, AM-8138 is an important new tool compound for the exploration of allosteric modulation of COX enzymes and their role in endocannabinoid metabolism. Copyright © 2015, The American Society for Biochemistry and Molecular Biology.
    Journal of Biological Chemistry 02/2015; 290(12). DOI:10.1074/jbc.M114.634014 · 4.57 Impact Factor
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    ABSTRACT: Cyclooxygenase (COX) is an enzyme involved in tumorigenesis and is associated with tumor cell resistance against platinum-based antitumor drugs. Cisplatin analogues were conjugated with COX inhibitors (indomethacin, ibuprofen) to study the synergistic effects that were previously observed in combination treatments. The conjugates ensure concerted transport of both drugs into cells, and subsequent intracellular cleavage enables a dual-action mode. Whereas the platinum(II) complexes showed cytotoxicities similar to those of cisplatin, the platinum(IV) conjugates revealed highly increased cytotoxic activities and were able to completely overcome cisplatin-related resistance. Although some of the complexes are potent COX inhibitors, the conjugates appear to execute their cytotoxic action via COX-independent mechanisms. Instead, the increased lipophilicity and kinetic inertness of the conjugates seem to facilitate cellular accumulation of the platinum drugs and thus improve the efficacy of the antitumor agents. These conjugates are important tools for the elucidation of the direct influence of COX inhibitors on platinum-based anticancer drugs in tumor cells.
    ChemMedChem 01/2015; 10(1). DOI:10.1002/cmdc.201402353 · 2.97 Impact Factor
  • Lawrence J. Marnett · Philip J. Kingsley · Daniel J. Hermanson
    The Endocannabinoidome, 01/2015: pages 49-65; , ISBN: 9780124201262
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    Shu Xu · Carol A Rouzer · Lawrence J Marnett
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    ABSTRACT: Oxicams are a class of nonsteroidal anti-inflammatory drugs (NSAIDs) structurally related to the enolic acid class of 4-hydroxy-1,2-benzothiazine carboxamides. They are used clinically to treat both acute and chronic inflammation by inhibiting the activity of the two cyclooxygenase (COX) isoforms, COX-1 and COX-2. Oxicams are structurally distinct from all other NSAIDs, exhibiting a novel binding pose in the COX active site. The 4-hydroxyl group on the thiazine ring partners with Ser-530 via hydrogen bonding while two coordinated water molecules mediate a polar interaction between the oxicam and COX. The rotation of Leu-531 in the complex opens a new pocket, which is not used for binding other NSAIDs to the enzyme. This structure provides the basis for understanding documented structure-activity relationships within the oxicam class. In addition, from the oxicam template, a series of potent microsomal prostaglandin E synthase-1 (mPGES-1) inhibitors represents a new direction for drug development. Here, we review the major route of oxicam synthesis and structure-activity for COX inhibition, as well as recent advances in oxicam-mediated mPGES-1 inhibition. © 2014 IUBMB Life, 2014. © 2014 International Union of Biochemistry and Molecular Biology.
    International Union of Biochemistry and Molecular Biology Life 12/2014; 66(12). DOI:10.1002/iub.1334 · 3.14 Impact Factor
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    ABSTRACT: Apoptolidin A has been described among the top 0.1 % most-cell-selective cytotoxic agents to be evaluated in the NCI 60 cell line panel. The molecular structure of apoptolidin A consists of a 20-membered macrolide with mono- and disaccharide moieties. In contrast to apoptolidin A, the aglycone (apoptolidinone) shows no cytotoxicity (>10 μM) when evaluated against several tumor cell lines. Apoptolidin H, the C27 deglycosylated analogue of apoptolidin A, displayed sub-micromolar activity against H292 lung carcinoma cells. Selective esterification of apoptolidins A and H with 5-azidopentanoic acid afforded azido-functionalized derivatives of potency equal to that of the parent macrolide. They also underwent strain-promoted alkyne–azido cycloaddition reactions to provide access to fluorescent and biotin-functionalized probes. Microscopy studies demonstrate apoptolidins A and H localize in the mitochondria of H292 human lung carcinoma cells.
    Angewandte Chemie International Edition 11/2014; 54(3). DOI:10.1002/anie.201408906 · 11.26 Impact Factor

Publication Stats

24k Citations
2,767.60 Total Impact Points


  • 1997–2015
    • Gateway-Vanderbilt Cancer Treatment Center
      Clarksville, Tennessee, United States
  • 1990–2015
    • Vanderbilt University
      • • Department of Biochemistry
      • • Center in Molecular Toxicology
      Nashville, Michigan, United States
  • 2011
    • University of Leipzig
      • Institute of Inorganic Chemistry
      Leipzig, Saxony, Germany
  • 2010
    • Molecular Toxicology, Inc.
      بون، كارولاينا الشمالية, North Carolina, United States
  • 2005
    • Kagawa University
      • Department of Biochemistry
      Takamatu, Kagawa, Japan
  • 2002
    • Massachusetts Institute of Technology
      Cambridge, Massachusetts, United States
  • 2001
    • University of Leicester
      • Department of Cancer Studies and Molecular Medicine
      Leiscester, England, United Kingdom
  • 1977–1997
    • Wayne State University
      • Department of Chemistry
      Detroit, MI, United States
  • 1994
    • University of Adelaide
      • Discipline of Clinical and Experimental Pharmacology
      Adelaide, South Australia, Australia
  • 1985
    • University of California, Berkeley
      Berkeley, California, United States
  • 1983
    • Oak Ridge National Laboratory
      Oak Ridge, Florida, United States