Publications by authors named "Kevin Coe"

18 Publications

  • Page 1 of 1

The Genetic Diversity of Cranberry Crop Wild Relatives, Aiton and L., in the US, with Special Emphasis on National Forests.

Plants (Basel) 2020 Oct 26;9(11). Epub 2020 Oct 26.

Department of Horticulture, University of Wisconsin, Madison, WI 53706, USA.

Knowledge of the genetic diversity in populations of crop wild relatives (CWR) can inform effective strategies for their conservation and facilitate utilization to solve agricultural challenges. Two crop wild relatives of the cultivated cranberry are widely distributed in the US. We studied 21 populations of Aiton and 24 populations of L. across much of their native ranges in the US using 32 simple sequence repeat (SSR) markers. We observed high levels of heterozygosity for both species across populations with private alleles ranging from 0 to 26. For , we found a total of 613 alleles and high levels of heterozygosity (H = 0.99, H = 0.75). We also observed high numbers of alleles (881) and levels of heterozygosity (H = 0.71, H = 0.80) in (4x). Our genetic analyses confirmed the field identification of a native population of on the Okanogan-Wenatchee National Forest in the state of Washington, far outside the previously reported range for the species. Our results will help to inform efforts of the United States Department of Agriculture Agricultural Research Service (USDA-ARS) and the United States Forest Service (USFS) to conserve the most diverse and unique wild cranberry populations through ex situ preservation of germplasm and in situ conservation in designated sites on National Forests.
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http://dx.doi.org/10.3390/plants9111446DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7716231PMC
October 2020

Is News Surveillance related to Cancer Knowledge in Underserved Adults? Testing Three Versions of the Cognitive Mediation Model.

Journal Stud 2020 23;21(9):1186-1199. Epub 2020 Mar 23.

Department of Communication, University of Utah.

The cognitive mediation model (CMM) proposes indirect paths to news learning such that news surveillance increases news learning through attention to the news and elaboration about the news. But there is a need for additional research that tests key postulates of the CMM especially for media targeting underserved populations. The present study tested three versions of the CMM to model ethnic newspaper learning within a low-income, Spanish-speaking population ( = 150). The original CMM was not supported by the data as elaboration was not related to knowledge; however, a simplified version of the CMM (surveillance → attention → knowledge) was supported. Moreover, a serial mediation model that included a measure of health maven was supported such that news surveillance was positively related to knowledge through maven-ness and attention.
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http://dx.doi.org/10.1080/1461670x.2020.1731706DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7577324PMC
March 2020

Substituted Azabicyclo[2.2.1]heptanes as Selective Orexin-1 Antagonists: Discovery of JNJ-54717793.

ACS Med Chem Lett 2020 Oct 27;11(10):2002-2009. Epub 2020 Apr 27.

Janssen Research & Development L.L.C., 3210 Merryfield Row, San Diego, California 92121, United States.

The orexin system consists of two neuropeptides (orexin-A and orexin-B) that exert their mode of action on two receptors (orexin-1 and orexin-2). While the role of the orexin-2 receptor is established as an important modulator of sleep wake states, the role of the orexin-1 receptor is believed to play a role in addiction, panic, or anxiety. In this manuscript, we describe the optimization of a nonselective substituted azabicyclo[2.2.1]heptane dual orexin receptor antagonist (DORA) into orally bioavailable, brain penetrating, selective orexin-1 receptor (OX1R) antagonists. This resulted in the discovery of our first candidate for clinical development, JNJ-54717793.
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http://dx.doi.org/10.1021/acsmedchemlett.0c00085DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7549262PMC
October 2020

Design, Synthesis, and Preclinical Evaluation of 3-Methyl-6-(5-thiophenyl)-1,3-dihydro-imidazo[4,5-]pyridin-2-ones as Selective GluN2B Negative Allosteric Modulators for the Treatment of Mood Disorders.

J Med Chem 2020 09 28;63(17):9181-9196. Epub 2020 Aug 28.

Janssen Research & Development, LLC, 3210 Merryfield Row, San Diego, California 92121-1126, United States.

Selective inhibitors of the GluN2B subunit of -methyl-d-aspartate receptors in the ionotropic glutamate receptor superfamily have been targeted for the treatment of mood disorders. We sought to identify structurally novel, brain penetrant, GluN2B-selective inhibitors suitable for evaluation in a clinical setting in patients with major depressive disorder. We identified a new class of negative allosteric modulators of GluN2B that contain a 1,3-dihydro-imidazo[4,5-]pyridin-2-one core. This series of compounds had poor solubility properties and poor permeability, which was addressed utilizing two approaches. First, a series of structural modifications was conducted which included replacing hydrogen bond donor groups. Second, enabling formulation development was undertaken in which a stable nanosuspension was identified for lead compound . Compound was found to have robust target engagement in rat with an ED of 1.4 mg/kg. The nanosuspension enabled sufficient margins in preclinical toleration studies to nominate for progression into advanced good laboratory practice studies.
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http://dx.doi.org/10.1021/acs.jmedchem.9b02113DOI Listing
September 2020

Optimization and biological evaluation of thiazole-bis-amide inverse agonists of RORγt.

Bioorg Med Chem Lett 2020 06 21;30(12):127205. Epub 2020 Apr 21.

Janssen Research and Development, LLC, San Diego, CA 92121, USA. Electronic address:

The nuclear receptor retinoic acid receptor-related orphan receptor gamma t (RORγt) is a transcription factor that drives Th17 cell differentiation and IL-17 production in both innate and adaptive immune cells. The IL-23/IL-17 pathway is implicated in major autoimmune and inflammatory diseases. RORγt lies at the core of this pathway and represents an attractive opportunity for intervention with small molecule therapeutics. Despite diverse chemical series having been reported, combining high potency and nuclear receptor selectivity with good physicochemical properties remains a challenging endeavor in the field of RORγt drug discovery. We recently described the discovery and evaluation of a new class of potent and selective RORγt inverse agonists based on a thiazole scaffold. Herein we describe the successful optimization of this class by incorporation of an additional amide moiety at the 4-position of the thiazole core. In several optimization cycles, we have reduced human PXR activation, improved solubility, and increased potency while maintaining nuclear receptor selectivity. X-ray crystallographic analysis of compound 1g bound in the sterol binding site of the ligand binding domain of RORγt was largely consistent with an earlier structure, guiding further insight into the molecular mechanism for RORγt inhibition with this series. Compound 1g is orally bioavailable, potent in a human whole blood assay and proved to be efficacious in an ex-vivo IL-17A assay, and was selected for preclinical evaluation.
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http://dx.doi.org/10.1016/j.bmcl.2020.127205DOI Listing
June 2020

Discovery of Imidazo[1,2-]pyrazines and Pyrazolo[1,5-]pyrimidines as TARP γ-8 Selective AMPAR Negative Modulators.

ACS Med Chem Lett 2019 Mar 26;10(3):267-272. Epub 2018 Dec 26.

Janssen Research & Development L.L.C., 3210 Merryfield Row, San Diego, California 92121 United States.

This report discloses the discovery and characterization of imidazo[1,2-]pyrazines and pyrazolo[1,5-]pyrimidines as selective negative modulators of α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors (AMPARs) associated with transmembrane AMPAR regulatory protein γ-8. Imidazopyrazine was initially identified as a promising γ-8 selective high-throughput screening hit, and subsequent structure-activity relationship optimization yielded subnanomolar, brain penetrant leads. Replacement of the imidazopyrazine core with an isosteric pyrazolopyrimidine scaffold improved microsomal stability and efflux liabilities to provide , JNJ-61432059. Following oral administration, exhibited time- and dose-dependent AMPAR/γ-8 receptor occupancy in mouse hippocampus, which resulted in robust seizure protection in corneal kindling and pentylenetetrazole (PTZ) anticonvulsant models.
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http://dx.doi.org/10.1021/acsmedchemlett.8b00599DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6421542PMC
March 2019

1-Pyrrolo[3,2-]pyridine GluN2B-Selective Negative Allosteric Modulators.

ACS Med Chem Lett 2019 Mar 10;10(3):261-266. Epub 2019 Jan 10.

Janssen Research & Development, LLC, 3210 Merryfield Row, San Diego, California 92121-1126, United States.

Herein, we disclose a series of selective GluN2B negative allosteric modulators containing a 1-pyrrolo[3,2-]pyridine core. Lead optimization efforts included increasing brain penetration as well as decreasing cytochrome P450 inhibition and hERG channel binding. The series was also optimized to reduce metabolic turnover in human and rat. Compounds , , , and have good in vitro GluN2B potency and good predicted absorption, but moderate to high projected clearance. They were assessed in vivo to determine their target engagement. All four compounds achieved >75% receptor occupancy after an oral dose of 10 mg/kg in rat. Compound receptor occupancy was measured in a dose-response experiment, and its ED was found to be 2.0 mg/kg.
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http://dx.doi.org/10.1021/acsmedchemlett.8b00542DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6421534PMC
March 2019

Carotenoid Presence Is Associated with the Gene in Domesticated Carrot.

Genetics 2018 12 23;210(4):1497-1508. Epub 2018 Oct 23.

Department of Horticulture, University of Wisconsin-Madison, Wisconsin 53706

Carrots are among the richest sources of provitamin A carotenes in the human diet, but genetic variation in the carotenoid pathway does not fully explain the high levels of carotenoids in carrot roots. Using a diverse collection of modern and historic domesticated varieties, and wild carrot accessions, an association analysis for orange pigmentation revealed a significant genomic region that contains the gene, advancing it as a candidate for carotenoid presence in carrot. Analysis of sequence variation at the locus revealed a nonsynonymous mutation cosegregating with carotenoid content. This mutation was absent in all wild carrot samples and nearly fixed in all orange domesticated samples. has been found to control carotenoid presence in other crops but has not previously been described in carrot. Our analysis also allowed us to more completely characterize the genetic structure of carrot, showing that the Western domesticated carrot largely forms one genetic group, despite dramatic phenotypic differences among market classes. Eastern domesticated and wild accessions form a second group, which reflects the recent cultivation history of carrots in Central Asia. Other wild accessions form distinct geographic groups, particularly on the Iberian peninsula and in Northern Africa. Using genome-wide , nucleotide diversity, and the cross-population composite likelihood ratio, we analyzed the genome for regions putatively under selection during domestication and identified 12 regions that were significant for all three methods of detection, one of which includes the gene. The domestication allele appears to have been selected after the initial domestication of yellow carrots in the East, near the proposed center of domestication in Central Asia. The rapid fixation of the domestication allele in almost all orange and nonorange carrots in the West may explain why it has not been found with less genetically diverse mapping populations.
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http://dx.doi.org/10.1534/genetics.118.301299DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6283172PMC
December 2018

Lead Optimization of 5-Aryl Benzimidazolone- and Oxindole-Based AMPA Receptor Modulators Selective for TARP γ-8.

ACS Med Chem Lett 2018 Aug 13;9(8):821-826. Epub 2018 Jul 13.

Janssen Research & Development L.L.C., 3210 Merryfield Row, San Diego, California 92121, United States.

Glutamate mediates fast excitatory neurotransmission via ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. The trafficking and gating properties of AMPA receptors (AMPARs) can be amplified by transmembrane AMPAR regulatory proteins (TARPs), which are often expressed in localized brain regions. Herein, we describe the discovery, lead optimization, and preclinical characterization of 5-arylbenzimidazolone and oxindole-based negative modulators of AMPARs associated with TARP γ-8, the primary TARP found in hippocampus. High-throughput screen lead was optimized for potency and brain penetration to provide benzimidazolone , JNJ-55511118.1 Replacement of the benzimidazolone core in with an oxindole mitigated reactive metabolite formation and led to the identification of (GluA1/γ-8 pIC = 9.7). Following oral dosing in rats, demonstrated robust target engagement in hippocampus as assessed by autoradiography (ED = 0.6 mg/kg, plasma EC = 9 ng/mL).
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http://dx.doi.org/10.1021/acsmedchemlett.8b00215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6088354PMC
August 2018

A Dipolar Cycloaddition Reaction To Access 6-Methyl-4,5,6,7-tetrahydro-1H-[1,2,3]triazolo[4,5-c]pyridines Enables the Discovery Synthesis and Preclinical Profiling of a P2X7 Antagonist Clinical Candidate.

J Med Chem 2018 01 20;61(1):207-223. Epub 2017 Dec 20.

Janssen Research & Development, LLC , 3210 Merryfield Row, San Diego, California 92121, United States.

A single pot dipolar cycloaddition reaction/Cope elimination sequence was developed to access novel 1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridine P2X7 antagonists that contain a synthetically challenging chiral center. The structure-activity relationships of the new compounds are described. Two of these compounds, (S)-(2-fluoro-3-(trifluoromethyl)phenyl)(1-(5-fluoropyrimidin-2-yl)-6-methyl-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl)methanone (compound 29) and (S)-(3-fluoro-2-(trifluoromethyl)pyridin-4-yl)(1-(5-fluoropyrimidin-2-yl)-6-methyl-1,4,6,7-tetrahydro-5H-[1,2,3]triazolo[4,5-c]pyridin-5-yl)methanone (compound 35), were found to have robust P2X7 receptor occupancy at low doses in rat with ED values of 0.06 and 0.07 mg/kg, respectively. Compound 35 had notable solubility compared to 29 and showed good tolerability in preclinical species. Compound 35 was chosen as a clinical candidate for advancement into phase I clinical trials to assess safety and tolerability in healthy human subjects prior to the initiation of proof of concept studies for the treatment of mood disorders.
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http://dx.doi.org/10.1021/acs.jmedchem.7b01279DOI Listing
January 2018

4-Methyl-6,7-dihydro-4H-triazolo[4,5-c]pyridine-Based P2X7 Receptor Antagonists: Optimization of Pharmacokinetic Properties Leading to the Identification of a Clinical Candidate.

J Med Chem 2017 06 25;60(11):4559-4572. Epub 2017 May 25.

Janssen Research & Development, LLC , 3210 Merryfield Row, San Diego, California 92121, United States.

The synthesis and preclinical characterization of novel 4-(R)-methyl-6,7-dihydro-4H-triazolo[4,5-c]pyridines that are potent and selective brain penetrant P2X7 antagonists are described. Optimization efforts based on previously disclosed unsubstituted 6,7-dihydro-4H-triazolo[4,5-c]pyridines, methyl substituted 5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrazines, and several other series lead to the identification of a series of 4-(R)-methyl-6,7-dihydro-4H-triazolo[4,5-c]pyridines that are selective P2X7 antagonists with potency at the rodent and human P2X7 ion channels. These novel P2X7 antagonists have suitable physicochemical properties, and several analogs have an excellent pharmacokinetic profile, good partitioning into the CNS and show robust in vivo target engagement after oral dosing. Improvements in metabolic stability led to the identification of JNJ-54175446 (14) as a candidate for clinical development. The drug discovery efforts and strategies that resulted in the identification of the clinical candidate are described herein.
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http://dx.doi.org/10.1021/acs.jmedchem.7b00408DOI Listing
June 2017

Effects of abiotic stress on physiological plasticity and water use of Setaria viridis (L.).

Plant Sci 2016 Oct 20;251:128-138. Epub 2016 Jul 20.

Department of Plant Sciences, University of California Davis, Davis, CA 95616, USA. Electronic address:

The emerging model Setaria viridis with its C4 photosynthesis and adaptation to hot and dry locations is a promising system to investigate water use and abiotic stress tolerance. We investigated the physiological plasticity of six S. viridis natural accessions that originated from different regions of the world under normal conditions and conditions of water-deficit stress and high temperatures. Accessions Zha-1, A10.1 and Ula-1 showed significantly higher leaf water potential (Ψleaf), photosynthesis (A), transpiration (E), and stomatal conductance (gs) rates compared to Ast-1, Aba-1 and Sha-1 when grown under stress conditions. Expression analysis of genes associated with C4 photosynthesis, aquaporins, ABA biosynthesis and signaling including genes involved in stress revealed an increased sensitivity of Ast-1, Aba-1 and Sha-1 to stresses. Correlation analysis of gene expression data with physiological and biochemical changes characterized A10.1 and Ast-1 as two extreme tolerant and sensitive accessions originated from United States and Azerbaijan under water-deficit and heat stress, respectively. Although preliminary, our study demonstrated the plasticity of S. viridis accessions under stress, and allows the identification of tolerant and sensitive accessions that could be use to study the mechanisms associated with stress tolerance and to characterize of the regulatory networks involved in C4 grasses.
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http://dx.doi.org/10.1016/j.plantsci.2016.06.011DOI Listing
October 2016

Identification of (R)-(2-Chloro-3-(trifluoromethyl)phenyl)(1-(5-fluoropyridin-2-yl)-4-methyl-6,7-dihydro-1H-imidazo[4,5-c]pyridin-5(4H)-yl)methanone (JNJ 54166060), a Small Molecule Antagonist of the P2X7 receptor.

J Med Chem 2016 09 8;59(18):8535-48. Epub 2016 Sep 8.

Janssen Pharmaceutical Research & Development, LLC , 3210 Merryfield Row, San Diego, California 92121 United States.

The synthesis and SAR of a series of 4,5,6,7-tetrahydro-imidazo[4,5-c]pyridine P2X7 antagonists are described. Addressing P2X7 affinity and liver microsomal stability issues encountered with this template afforded methyl substituted 4,5,6,7-tetrahydro-imidazo[4,5-c]pyridines ultimately leading to the identification of 1 (JNJ 54166060). 1 is a potent P2X7 antagonist with an ED50 = 2.3 mg/kg in rats, high oral bioavailability and low-moderate clearance in preclinical species, acceptable safety margins in rats, and a predicted human dose of 120 mg of QD. Additionally, 1 possesses a unique CYP profile and was found to be a regioselective inhibitor of midazolam CYP3A metabolism.
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http://dx.doi.org/10.1021/acs.jmedchem.6b00989DOI Listing
September 2016

The fragmented mitochondrial ribosomal RNAs of Plasmodium falciparum.

PLoS One 2012 22;7(6):e38320. Epub 2012 Jun 22.

Seattle Biomedical Research Institute, Seattle, Washington, United States of America.

Background: The mitochondrial genome in the human malaria parasite Plasmodium falciparum is most unusual. Over half the genome is composed of the genes for three classic mitochondrial proteins: cytochrome oxidase subunits I and III and apocytochrome b. The remainder encodes numerous small RNAs, ranging in size from 23 to 190 nt. Previous analysis revealed that some of these transcripts have significant sequence identity with highly conserved regions of large and small subunit rRNAs, and can form the expected secondary structures. However, these rRNA fragments are not encoded in linear order; instead, they are intermixed with one another and the protein coding genes, and are coded on both strands of the genome. This unorthodox arrangement hindered the identification of transcripts corresponding to other regions of rRNA that are highly conserved and/or are known to participate directly in protein synthesis.

Principal Findings: The identification of 14 additional small mitochondrial transcripts from P. falciparum and the assignment of 27 small RNAs (12 SSU RNAs totaling 804 nt, 15 LSU RNAs totaling 1233 nt) to specific regions of rRNA are supported by multiple lines of evidence. The regions now represented are highly similar to those of the small but contiguous mitochondrial rRNAs of Caenorhabditis elegans. The P. falciparum rRNA fragments cluster on the interfaces of the two ribosomal subunits in the three-dimensional structure of the ribosome.

Significance: All of the rRNA fragments are now presumed to have been identified with experimental methods, and nearly all of these have been mapped onto the SSU and LSU rRNAs. Conversely, all regions of the rRNAs that are known to be directly associated with protein synthesis have been identified in the P. falciparum mitochondrial genome and RNA transcripts. The fragmentation of the rRNA in the P. falciparum mitochondrion is the most extreme example of any rRNA fragmentation discovered.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0038320PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3382252PMC
March 2013

Comparison of in vitro bioactivation of flutamide and its cyano analogue: evidence for reductive activation by human NADPH:cytochrome P450 reductase.

Chem Res Toxicol 2008 Dec;21(12):2393-406

Department of Drug Metabolism and Pharmacokinetics, Roche Palo Alto, Palo Alto, California 94304, USA.

Flutamide (FLU), a nonsteroidal antiandrogen drug widely used in the treatment of prostate cancer, has been associated with idiosyncratic hepatotoxicity in patients. It is proposed that bioactivation of FLU and subsequent binding of reactive metabolite(s) to cellular proteins play a causative role. A toxicogenomic study comparing FLU and its nitro to cyano analogue (CYA) showed that the nitroaromatic group of FLU enhanced cytotoxicity to hepatocytes, indicating that reduction of the nitroaromatic group may represent a potential route of FLU-induced hepatotoxicity [Coe et al. (2007) Chem. Res. Toxicol. 20, 1277-1290]. In the current study, we compared in vitro bioactivation of FLU and CYA in human liver microsomes and cryopreserved human hepatocytes. A nitroreduction metabolite FLU-6 was formed in liver microsomal incubations of FLU under atmospheric oxygen levels and, to a greater extent, under anaerobic conditions. Seven glutathione (GSH) adducts of FLU, FLU-G1-7, were tentatively identified in human liver microsomal incubations using liquid chromatography-tandem mass spectrometry (LC/ MS/MS), while CYA formed only four corresponding GSH adducts, CYA-G1-4, under the same conditions. Of particular interest was the formation of FLU-G5-7 from FLU, where the nitroaromatic group of FLU was reduced to an amino group. A tentative pathway is that upon nitroreduction, the para-diamines undergo cytochrome P450 (P450)-catalyzed two-electron oxidations to form corresponding para-diimine intermediates that react with GSH to form GSH adducts FLU-G5-7, respectively. The identities of FLU-G5-7 were further confirmed by LC/MS/MS analyses of microsomal incubations of a synthesized standard FLU-6. In an attempt to identify enzymes involved in the nitroreduction of FLU, NADPH:cytochrome P450 reductase (CPR) was shown to reduce FLU to FLU-6 under both aerobic and anaerobic conditions. Furthermore, the formation of FLU-G5-7 was completely blocked by the addition of a reversible CPR inhibitor, alpha-lipoic acid, to the incubations of FLU under aerobic conditions. In summary, these results clearly demonstrate that nitroreduction of FLU by CPR contributes to bioactivation and potentially to hepatotoxicity of FLU.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2802856PMC
http://dx.doi.org/10.1021/tx800281hDOI Listing
December 2008

Comparison of the cytotoxicity of the nitroaromatic drug flutamide to its cyano analogue in the hepatocyte cell line TAMH: evidence for complex I inhibition and mitochondrial dysfunction using toxicogenomic screening.

Chem Res Toxicol 2007 Sep 17;20(9):1277-90. Epub 2007 Aug 17.

Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA.

Flutamide (FLU) is an antiandrogen primarily used in the treatment of metastatic prostate cancer. It is an idiosyncratic hepatotoxicant that sometimes results in severe liver toxicity. FLU possesses a nitroaromatic group, which may be a contributor to its mechanism of toxicity. A nitro to cyano analogue of FLU (CYA) was synthesized and used to test this hypothesis in the TGFalpha-transfected mouse hepatocyte cell line (TAMH). MTT cell viability assays and confocal microscopy showed that hepatocytes are more sensitive to cytotoxicity caused by FLU than CYA (LD 50 75 vs 150 microM, respectively). Despite the structural modification, the antiandrogen activity of CYA is comparable to that of FLU. Comparisons of transcriptomic changes caused by FLU with those caused by a panel of known cytotoxicants [acetaminophen, tetrafluoroethylcysteine, diquat, and rotenone (ROT)] indicated that FLU results in a temporal gene expression pattern similar to ROT, a known inhibitor of complex I of the electron transport chain. A subsequent microarray analysis comparing FLU to CYA and ROT revealed many similarities among these three compounds; however, FLU and ROT result in more substantial changes than CYA in the expression of genes associated with oxidative phosphorylation, fatty acid beta-oxidation, antioxidant defense, and cell death pathways. Electron microscopy confirmed that FLU leads to mitochondrial toxicity that has some similarities to the mitochondrial effects of ROT, but the morphologic changes caused by FLU were greater in scope with both intra- and intercellular manifestations. Biochemical studies confirmed that both ROT and FLU deplete cellular ATP levels and inhibit complex I of the electron transport chain to a greater extent than CYA. Thus, as compared to CYA, the nitroaromatic group of FLU enhances cytotoxicity to hepatocytes, likely through mechanisms involving mitochondrial dysfunction and ATP depletion that include complex I inhibition.
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http://dx.doi.org/10.1021/tx7001349DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2802183PMC
September 2007

Cytosolic heat shock proteins and heme oxygenase-1 are preferentially induced in response to specific and localized intramitochondrial damage by tetrafluoroethylcysteine.

Biochem Pharmacol 2006 Jun 29;72(1):80-90. Epub 2006 Mar 29.

Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195, USA.

Previously, S-(1,1,2,2-tetrafluoroethyl)-l-cysteine (TFEC) was shown to mediate cytotoxicity by covalently modifying a well-defined group of intramitochondrial proteins including aconitase, alpha-ketoglutarate dehydrogenase (alphaKGDH) subunits, heat shock protein 60 (HSP60) and mitochondrial HSP70 (mtHSP70). To investigate the cellular responses to this mitochondrial damage, microarray analysis of TFEC treated murine hepatocytes of the TAMH cell line was carried out. Results of these studies revealed a HSP response that was significantly stronger than other well-characterized hepatotoxicants including acetaminophen, diquat and rotenone. Specifically, cytosolic HSP25, HSP40, HSP70, HSP105 and microsomal HSP32 (HO-1) were strongly upregulated within the first few hours of TFEC treatment, while little change was observed among other HSPs that are predominantly localized in the mitochondria and endoplasmic reticulum (ER). Post-translational modification of HSP25 was also observed with the appearance of a unique DTT-resistant immunoreactive band at about 50kDa, a putative dimer. The biological significance of HSP responses to TFEC-induced toxicity were subsequently demonstrated using the "gain of function" pretreatment: heat shock. Overall, we report an atypical HSP induction profile that does not conform to changes expected of a classical temperature shock. Furthermore, despite a well-defined intramitochondrial origin of toxicity, TFEC rapidly evokes an early and strong upregulation of cytosolic stress proteins. The cytoprotective effects of such HSP responses suggest a plausible role in modulating the progression of TFEC-induced cellular injury.
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http://dx.doi.org/10.1016/j.bcp.2006.03.019DOI Listing
June 2006

Profiling the hepatic effects of flutamide in rats: a microarray comparison with classical aryl hydrocarbon receptor ligands and atypical CYP1A inducers.

Drug Metab Dispos 2006 Jul 12;34(7):1266-75. Epub 2006 Apr 12.

Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA.

The antiandrogen flutamide (FLU) is used primarily for prostate cancer and is an idiosyncratic hepatotoxicant that sometimes causes severe liver problems. To investigate FLU's overt hepatic effects, especially on inducible drug clearance-related gene networks, FLU's hepatic gene expression profile was examined in female Sprague-Dawley rats using approximately 22,500 oligonucleotide microarrays. Rats were dosed daily for 3 days with FLU at 500, 250, 62.5, 31.3, and 15.6 mg/kg/day, and hepatic RNA was isolated. FLU resulted in the dose-dependent regulation of approximately 350 genes. Employing a gene-response compendium, FLU was compared with three classical aryl hydrocarbon receptor (AhR) ligands, 3-methylcholanthrene, benzo[a]pyrene, and beta-naphthoflavone, and four atypical CYP1A inducers, indole-3-carbinol (I3C), omeprazole (OME), chlorpromazine (CPZ), and clotrimazole (CLO). The FLU gene response was comparable with classical AhR ligands across a signature AhR ligand gene set that included CYP1A1 and other members of the AhR gene battery. Dose-related responses of CYP1 genes established a maximum response ceiling and discerned potency differences in atypical inducers. FLU had a sharp down-regulation of c-fos that was comparable with all the compounds except CPZ and CLO. FLU absorption, distribution, metabolism, and excretion (ADME) gene expression analysis revealed that FLU, as well as I3C and OME, induced CYP2B and CYP3A, distinguishing them from the classical AhR ligands. By using a compendium of gene expression profiles, FLU was shown to signal in rats similar to an AhR activator with additional CYP2B and CYP3A effects that most resembled the ADME gene expression pattern of the atypical CYP1A inducers I3C and OME.
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http://dx.doi.org/10.1124/dmd.105.009159DOI Listing
July 2006