Prostate Cancer Expression Profiles of Cytoplasmic ERβ1 and Nuclear ERβ2 are Associated with Poor Outcomes following Radical Prostatectomy.

Purpose: Existing data regarding the expression of estrogen receptors (ERs) and prostate cancer outcomes have been limited. We evaluated the relationship of expression profiles of ERβ subtypes and the ER GPR30 (G-protein-coupled receptor-30) with patient factors at diagnosis and outcomes following radical prostatectomy.

Materials And Methods: Tissue microarrays constructed using samples from 566 men with long-term clinical followup were analyzed by immunohistochemistry targeting ERβ1, ERβ2, ERβ5 and GPR30.

Ah Receptor Signaling Controls the Expression of Cardiac Development and Homeostasis Genes.

Congenital heart disease (CHD) is the most common congenital abnormality and one of the leading causes of newborn death throughout the world. Despite much emerging scientific information, the precise etiology of this disease remains elusive. Here, we show that the aryl hydrocarbon receptor (AHR) regulates the expression of crucial cardiogenesis genes and that interference with endogenous AHR functions, either by gene ablation or by agonist exposure during early development, causes overlapping structural and functional cardiac abnormalities that lead to altered fetal heart physiology, including higher heart rates, right and left ventricle dilation, higher stroke volume, and reduced ejection fraction.

Manipulation of olfactory tight junctions using papaverine to enhance intranasal delivery of gemcitabine to the brain.

Context: Delivery of drugs from the nasal cavity to the brain is becoming more widely accepted, due to the non-invasive nature of this route and the ability to circumvent the blood brain barrier (BBB).

Objective: Because of similarities in the proteins comprising the olfactory epithelial tight junction (TJ) proteins and those of the BBB, we sought to determine whether papaverine (PV), which is known to reversibly enhance BBB permeability, could increase the delivery of intranasally administered gemcitabine to the central nervous system in rats. Experimental methods: Included intranasal administration of gemcitabine, fluorescein isothiocyanate-dextran beads and PV, histopathology, immunostaining, RT-PCR, western blot analysis, immunofluorescence localization, spectrofluorometric analysis, in vivo brain microdialysis, HPLC analysis and in vitro gemcitabine recovery.

Induction of oxidative stress responses by dioxin and other ligands of the aryl hydrocarbon receptor.

TCDD and other polyhalogenated aromatic hydrocarbon ligands of the aryl hydrocarbon receptor (AHR) have been classically considered as non-genotoxic compounds because they fail to be directly mutagenic in either bacteria or most in vitro assay systems. They do so in spite of having repeatedly been linked to oxidative stress and to mutagenic and carcinogenic outcomes. Oxidative stress, on the other hand, has been used as a marker for the toxicity of dioxin and its congeners.

HDAC1 bound to the Cyp1a1 promoter blocks histone acetylation associated with Ah receptor-mediated trans-activation.

Metabolic bioactivation of polycyclic aromatic hydrocarbons, such as the environmental procarcinogen benzo[a]pyrene, is catalyzed by a cytochrome P450 monooxygenase encoded by the substrate-inducible Cyp1a1 gene. Cyp1a1 induction requires trans-activation by the heterodimeric transcriptional complex formed by the liganded Ah receptor (AHR) and its partner, ARNT. Previously, we showed that constitutively bound HDAC1 dissociates from Cyp1a1 promoter chromatin after ligand-mediated induction, concomitantly with the recruitment of AHR/ARNT complexes and p300.

Long term low-dose arsenic exposure induces loss of DNA methylation.

Arsenic ranks as the number one toxic environmental contaminant. In humans, arsenic exposure is associated with various forms of cancer, cardiovascular and skin diseases, neuropathies of the central nervous system, and genotoxic and immunotoxic effects. Although a well recognized human carcinogen, arsenic itself is not a potent mutagen and has been thought to act through epigenetic mechanisms that modify DNA methylation patterns, perhaps in conjunction with DNA-damaging agents.

Butylhydroquinone protects cells genetically deficient in glutathione biosynthesis from arsenite-induced apoptosis without significantly changing their prooxidant status.

Arsenic, first among the top environmentally hazardous substances, is associated with skin, lung, liver, kidney, prostate, and bladder cancer. Arsenic is also a cardiovascular and a central nervous system toxicant, and it has genotoxic and immunotoxic effects. Paradoxically, arsenic trioxide is used successfully in the treatment of acute promyelocytic leukemia and multiple myeloma.

Ah receptor signals cross-talk with multiple developmental pathways.

For many years, the Ah receptor (AHR) has been a favorite of toxicologists and molecular biologists studying the connections between genes and the changes in the control of gene expression resulting from environmental exposures. Much of the attention given to the Ah receptor has focused on the nature of its ligands, many of which are known or suspected carcinogens, and on the role that its best studied regulatory product, the CYP1A1 enzyme, plays in toxic responses and carcinogen activation. This understandable bias has resulted in a disproportionate amount of Ah receptor research being directed at toxicological or adaptive end points.

Gene expression profiles of mouse aorta and cultured vascular smooth muscle cells differ widely, yet show common responses to dioxin exposure.

Exposure to environmental toxicants may play a role in the onset and progression of cardiovascular disease. Many environmental agents, such as dioxin, are risk factors for atherosclerosis because they may exacerbate an underlying disease by altering gene expression patterns. Expression profiling of vascular tissues allows the simultaneous analysis of thousands of genes and may provide predictive information particularly useful in early disease stages.

A critical role for MAP kinases in the control of Ah receptor complex activity.

The heterodimeric complex of aromatic hydrocarbon receptor (AHR) and Ah receptor nuclear translocator (ARNT) plays a pivotal role in controlling the expression of drug metabolism genes, such as the cytochromes p450 (Cyp) 1a1 and 1b1, believed to be responsible for most toxic effects of the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In this study, we show that activation of Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) modulates ARNT transcription activity and potentiates the transcriptional activity of AHR/ARNT complexes. Inhibition of ERK by chemical compounds and ablation of JNK caused significant decreases in CYP1A1 induction by TCDD.

The aryl hydrocarbon receptor displaces p300 from E2F-dependent promoters and represses S phase-specific gene expression.

The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes a wide range of toxic, teratogenic, and carcinogenic effects. TCDD is a ligand for the aromatic hydrocarbon receptor (AHR), a ligand-activated transcription factor believed to be the primary mediator of these effects. Activation of the AHR by TCDD also elicits a variety of effects on cell cycle progression, ranging from proliferation to arrest.

The control of cell motility and epithelial morphogenesis by Jun kinases.

Originally identified as stress-activated protein kinases that control cell survival and proliferation through transcription factor c-Jun, the Jun N-terminal kinase (JNK) subgroup of MAP kinases (MAPKs) have recently emerged as crucial regulators of cell migration and the morphogenetic movement of epithelial sheets. In Drosophila, a well-orchestrated JNK signaling pathway controls formation of actin stress fibers and cell shape changes, which are required for the sealing of embryonic epidermis in a process known as dorsal closure. The JNK pathway is also involved in morphogenetic processes in mice including closure of the eyelid, neural tube and optic fissure.

MEK kinase 1 regulates c-Jun phosphorylation in the control of corneal morphogenesis.

Purpose: To study the in vivo role of MEK kinase 1 (MEKK1) in corneal development.

Methods: Wild type and Mekk1DeltaKD/DeltaKD mice eye tissues were examined by staining with hematoxylin and eosin for morphogenesis and Masson's trichrome for extracellular matrix (ECM) deposition. The cells expressing ECM gene transcripts of Collagen I, Keratocan, and Lumican in corneal stroma were identified by in situ hybridization and the level of Collagen I mRNA in the developing cornea was quantified by real-time RT-PCR.

Chromium inhibits transcription from polycyclic aromatic hydrocarbon-inducible promoters by blocking the release of histone deacetylase and preventing the binding of p300 to chromatin.

Co-contamination with complex mixtures of carcinogenic metals, such as chromium, and polycyclic aromatic hydrocarbons is a common environmental problem with multiple biological consequences. Chromium exposure alters inducible gene expression, forms chromium-DNA adducts and chromium-DNA cross-links, and disrupts transcriptional activator-co-activator complexes. We have shown previously that exposure of mouse hepatoma Hepa-1 cells to chromate inhibits the induction of the Cyp1a1 and Nqo1 genes by dioxin.

Clinical importance of the cytochromes P450.

The human cytochrome P450 (CYP) superfamily comprises 57 genes. These genes code for enzymes that can have a role in: metabolism of drugs, foreign chemicals, arachidonic acid and eicosanoids; cholesterol metabolism and bile-acid biosynthesis; steroid synthesis and metabolism; vitamin D(3) synthesis and metabolism; retinoic acid hydroxylation; and those of still unknown function. Cytochrome P450 was once believed to be mainly a hepatic drug detoxication system, but is now understood to include a myriad of enzymic reactions implicated in important life processes.

Dioxin exposure is an environmental risk factor for ischemic heart disease.

Epidemiologic studies have linked dioxin exposure to increased mortality caused by ischemic heart disease. To test the hypothesis that dioxin exposure may constitute an environmental risk factor for atherosclerosis, we exposed C57BL/6J mice to 5 microg/kg of dioxin daily for 3 d, and measured various molecular and physiological markers of heart disease. Dioxin treatment led to an increase in the urinary excretion of vasoactive eicosanoids and an elevation in the mean tail-cuff blood pressure.

Role of the aryl hydrocarbon receptor in cell cycle regulation.

Traditionally, the aryl hydrocarbon receptor (AHR) is considered to be a ligand-activated receptor and transcription factor responsible for the induction of drug-metabolizing enzymes. Its role in the combinatorial matrix of cell functions was neatly established long before the first report of an AHR cDNA sequence was published. Only recently, other functions of this protein have begun to be recognized.

Knockout of the mouse glutamate cysteine ligase catalytic subunit (Gclc) gene: embryonic lethal when homozygous, and proposed model for moderate glutathione deficiency when heterozygous.

The biosynthesis of reduced glutathione (GSH) is carried out by the enzymes gamma-glutamylcysteine synthetase (GCL) and GSH synthetase. GCL is the rate-limiting step and represents a heterodimeric enzyme comprised of a catalytic subunit (GCLC) and a ("regulatory"), or modifier, subunit (GCLM). The nonhomologous Gclc and Gclm genes are located on mouse chromosomes 9 and 3, respectively.

"Gene-swap knock-in" cassette in mice to study allelic differences in human genes.

Genetic differences in environmental toxicity and cancer susceptibility among individuals in a human population often reflect polymorphisms in the genes encoding drug-metabolizing enzymes (DMEs), drug transporters, and receptors that control DME levels. This field of study is called "ecogenetics", and a subset of this field--concerning genetic variability in response to drugs--is termed "pharmacogenetics". Although human-mouse differences might be 3- to perhaps 10-fold, human interindividual differences can be as great as 20-fold or more than 40-fold.

Transgenic zebrafish as sentinels for aquatic pollution.

Using the golden mutant zebrafish having a decrease in interfering pigmentation, we are developing transgenic lines in which DNA motifs that respond to selected environmental pollutants are capable of activating a reporter gene that can be easily assayed. We have begun with three response elements that recognize three important classes of foreign chemicals. Aromatic hydrocarbon response elements (AHREs) respond to numerous polycyclic hydrocarbons and halogenated coplanar molecules such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin) and polychlorinated biphenyls.

The transcriptional signature of dioxin in human hepatoma HepG2 cells.

We have used a high density microarray hybridization approach to characterize the transcriptional response of human hepatoma HepG2 cells to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). We find that exposure to 10 nM TCDD for 8 hr alters by at least a factor of 2.1 the expression of 310 known genes and of an equivalent number of expressed sequence tags.

Suggestions for the nomenclature of human alleles: relevance to ecogenetics, pharmacogenetics and molecular epidemiology.

The current number of 9422 symbols for human gene names (http://www.gene.ucl.

Tissue- and cell type-specific expression of cytochrome P450 1A1 and cytochrome P450 1A2 mRNA in the mouse localized in situ hybridization.

We used in situ hybridization to examine organ- and cell type-specific constitutive and 3-methylcholanthrene (3MC)-inducible cytochrome P450 (CYP)1A1 and CYP1A2 mRNA expression in various tissues of the C57BL/6N mouse. In situ hybridization was carried out 10 hr after the mice had received intraperitoneal 3MC, or vehicle alone. We detected levels of 3MC-induced CYP1A1 mRNA in: liver (centrilobular, more so than periportal, regions); lung (Clara Type II cells much more than Type I epithelial cells); brain, especially endothelial cells lining the vascular surface of the choroid plexus; the digestive tract (duodenum > jejunum > ileum > colon > esophagus > stomach--in particular, the villous epithelium, plus cells surrounding glands in the lamina propria); renal corpuscles of the kidney; the ovary (medulla more so than cortex); and the endothelial cells of blood vessels throughout the animal.

Trout CYP1A3 Gene: Recognition of Fish DNA Motifs by Mouse Regulatory Proteins.

: Transcriptional up-regulation of mammalian CYP1A1 genes by dioxin is known to require binding of dioxin to the Ah receptor (AHR), subsequent interaction of this ligand-receptor complex with the AHR nuclear translocator (ARNT), and binding of this heterodimer to aromatic hydrocarbon response elements (AHREs) located in the 5' flanking sequences. From the rainbow trout (Oncorhyncus mykiss), we have isolated and sequenced the CYP1A3 gene-spanning 4.0 kb and containing seven exons and six introns-and 1897 bp of the 5' flanking region.

Markedly increased constitutive CYP1A1 mRNA levels in the fertilized ovum of the mouse.

Using a highly sensitive RT-PCR technique that measures mRNA (cDNA)-to-DNA ratios, we are able to detect constitutive CYP1A1 mRNA in adult mouse liver as well as in the oocyte. Twelve hours after fertilization of the ovum, there is a more than 100-fold increase in constitutive CYP1A1 mRNA levels; this dramatic increase completely disappears by the 2-cell stage at gestational day 1.5 (GD1.