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Sample records for placental aromatase cytochrome

  1. Placental expression and molecular characterization of aromatase cytochrome P450 in the spotted hyena (Crocuta crocuta).

    PubMed

    Conley, A J; Corbin, C J; Browne, P; Mapes, S M; Place, N J; Hughes, A L; Glickman, S E

    2007-07-01

    At birth, the external genitalia of female spotted hyenas (Crocuta crocuta) are the most masculinized of any known mammal, but are still sexually differentiated. Placental aromatase cytochrome P450 (P450arom) is an important route of androgen metabolism protecting human female fetuses from virilization in utero. Therefore, placental P450arom expression was examined in spotted hyenas to determine levels during genital differentiation, and to compare molecular characteristics between the hyena and human placental enzymes. Hyena placental P450arom activity was determined at gestational days (GD) 31, 35, 45, 65 and 95 (term, 110), and the relative sensitivity of hyena and human placental enzyme to inhibition by the specific inhibitor, Letrozole, was also examined. Expression of hyena P450arom in placenta was localized by immuno-histochemistry, and a full-length cDNA was cloned for phylogenetic analysis. Aromatase activity increased from GD31 to a peak at 45 and 65, apparently decreasing later in gestation. This activity was more sensitive to inhibition by Letrozole than was human placental aromatase activity. Expression of P450arom was localized to syncytiotrophoblast and giant cells of mid-gestation placentas. The coding sequence of hyena P450arom was 94% and 86% identical to the canine and human enzymes respectively, as reflected by phylogenetic analyses. These data demonstrate for the first time that hyena placental aromatase activity is comparable to that of human placentas when genital differentiation is in progress. This suggests that even in female spotted hyenas clitoral differentiation is likely protected from virilization by placental androgen metabolism. Decreased placental aromatase activity in late gestation may be equally important in allowing androgen to program behaviors at birth. Although hyena P450arom is closely related to the canine enzyme, both placental anatomy and P450arom expression differ. Other hyaenids and carnivores must be investigated to

  2. Higher order organization of human placental aromatase.

    PubMed

    Ghosh, Debashis; Jiang, Wenhua; Lo, Jessica; Egbuta, Chinaza

    2011-07-01

    Aromatase (CYP19A1) is an integral membrane enzyme that catalyzes the removal of the 19-methyl group and aromatization of the A-ring of androgens. All human estrogens are synthesized from their androgenic precursors by this unique cytochrome P450. The crystal structure of active aromatase purified from human placenta has recently been determined in complex with its natural substrate androstenedione in the high-spin ferric state of heme. Hydrogen bond forming interactions and tight packing hydrophobic side chains closely complement puckering of the steroid backbone, thereby providing the molecular basis for the androgenic specificity of aromatase. In the crystal, aromatase molecules are linked by a head-to-tail intermolecular interaction via a surface loop between helix D and helix E of one aromatase molecule that penetrates the heme-proximal cavity of the neighboring, crystallographically related molecule, thus forming in tandem a polymeric aromatase chain. This intermolecular interaction is similar to the aromatase-cytochrome P450 reductase coupling and is driven by electrostatics between the negative potential surface of the D-E loop region and the positively charged heme-proximal cavity. This loop-to-proximal site link in aromatase is rather unique--there are only a few of examples of somewhat similar intermolecular interactions in the entire P450 structure database. Furthermore, the amino acids involved in the intermolecular contact appear to be specific for aromatase. Higher order organization of aromatase monomers may have implications in lipid integration and catalysis.

  3. Aromatase activity modulation by lindane and bisphenol-A in human placental JEG-3 and transfected kidney E293 cells.

    PubMed

    Nativelle-Serpentini, C; Richard, S; Séralini, G-E; Sourdaine, P

    2003-08-01

    Aromatase is the cytochrome P-450 involved in converting androgens to estrogens. The cytochrome P-450 family plays a central role in the oxidative metabolism of compounds including environmental pollutants. Since lindane and bisphenol-A (BPA) are two well-characterized endocrine disruptors that have been detected in animals and humans, it was important to learn whether they could affect aromatase activity and consequently estrogen biosynthesis. The present study investigates the effects of BPA and lindane on cytotoxicity, aromatase activity and mRNA levels in human placental JEG-3 cells and transfected human embryonal kidney 293 cells. Both cell lines were exposed to increasing concentrations of lindane (25, 50 and 75 microM) and bisphenol-A (25, 50 and 100 microM) over different time periods (10 min-18 h). As a result, none of these concentrations showed cytotoxicity. After short pre-incubation times (10 min-6 h), aromatase activity was enhanced by both compounds. Longer time incubation (18 h), however, produced dose-related inhibition. Lindane and BPA had no significant effects on CYP19 mRNA levels. Therefore, lindane and BPA modulate aromatase activity suggesting an interaction with the cytochrome P-450 aromatase. This study highlights the endocrine-modulating properties of lindane and bisphenol-A.

  4. The effect of opiates on the activity of human placental aromatase/CYP19.

    PubMed

    Zharikova, Olga L; Deshmukh, Sujal V; Kumar, Meena; Vargas, Ricardo; Nanovskaya, Tatiana N; Hankins, Gary D V; Ahmed, Mahmoud S

    2007-01-15

    Aromatase, cytochrome P450 19, is a key enzyme in the biosynthesis of estrogens by the human placenta. It is also the major placental enzyme that metabolizes the opiates L-acetylmethadol (LAAM), methadone, and buprenorphine (BUP). Methadone and BUP are used in treatment of the opiate addict and are competitive inhibitors of testosterone conversion to estradiol (E(2)) and 16alpha-hydroxytestosterone (16-OHT) to estriol (E(3)) by aromatase. The aim of this investigation is to determine the effect of 20 opiates, which can be administered to pregnant patients for therapeutic indications or abused, on E(2) and E(3) formation by placental aromatase. Data obtained indicated that the opiates increased, inhibited, or had no effect on aromatase activity. Their effect on E(3) formation was more pronounced than that on E(2) due to the lower affinity of 16-OHT than testosterone to aromatase. The K(i) values for the opiates that inhibited E(3) formation were sufentanil, 7 +/- 1 microM; LAAM, 13 +/- 8 microM; fentanyl, 25 +/- 5 microM; oxycodone, 92 +/- 22 microM; codeine, 218 +/- 69 microM; (+)-pentazocine, 225 +/- 73 microM. The agonists morphine, heroin, hydromorphone, oxymorphone, hydrocodone, propoxyphene, meperidine, levorphanol, dextrorphan, and (-)-pentazocine and the antagonists naloxone and naltrexone caused an increase in E(3) formation by 124-160% of control but had no effect on E(2) formation. Moreover, oxycodone and codeine did not inhibit E(2) formation and the IC(50) values for fentanyl, sufentanil, and (+)-pentazocine were >1000 microM. It is unlikely that the acute administration of the opiates that inhibit estrogen formation would affect maternal and/or neonatal outcome. However, the effects of abusing any of them during the entire pregnancy are unclear at this time.

  5. Isolation and characterization of a complementary DNA specific for human aromatase-system cytochrome P-450 mRNA.

    PubMed Central

    Evans, C T; Ledesma, D B; Schulz, T Z; Simpson, E R; Mendelson, C R

    1986-01-01

    A cloned complementary DNA sequence has been isolated from a human placental cDNA library in the bacteriophage expression vector lambda gt11 after screening with polyclonal antibodies against human placental aromatase-system cytochrome P-450 (P-450Arom). A single recombinant clone, lambda hAROM1, was characterized by its ability to generate a beta-galactosidase fusion protein that reacted independently with polyclonal antibodies raised against beta-galactosidase and cytochrome P-450Arom and with monoclonal antibodies specific for cytochrome P-450Arom. The cDNA insert, which was found to be 1.8 kilobases in length, was radiolabeled and used to analyze poly(A)+ RNA isolated from human placenta and total RNA isolated from human adipose stromal cells cultured in the absence or presence of regulatory factors. The radiolabeled cDNA hybridized to several size species of mRNA in both placental and adipose stromal cell RNA fractions. Changes in the levels of adipose stromal cell RNA that hybridized to the cDNA insert were associated with comparable changes in the levels of translatable cytochrome P-450Arom mRNA and aromatase system activity. These findings are indicative that lambda hAROM1 contains DNA sequences complementary to human cytochrome P-450Arom mRNA and are suggestive that regulatory factors affect aromatase activity by altering the transcriptional activity of the cytochrome P-450Arom gene. Images PMID:3018730

  6. Immunohistochemical localization of cytochrome P450 aromatase in equine gonads.

    PubMed

    Almadhidi, J; Seralini, G E; Fresnel, J; Silberzahn, P; Gaillard, J L

    1995-06-01

    Estrogens are the major steroids produced by equine gonads. To identify the cells responsible for estrogen synthesis, an antiserum against purified equine testicular cytochrome P450 aromatase was produced in rabbits. The reactivity and specificity of the antiserum were assessed by ELISA, immunoblot analysis, and immunoneutralization studies. Immunofluorescence microscopy demonstrated that in the male gonad, cytochrome P450 aromatase (P450arom) was localized in the interstitial tissue, whereas, under the experimental conditions used, the Sertoli and germ cells did not show any specific staining. In the ovary, the granulosa cells of small follicles exhibited faint immunofluorescent staining for P450arom and the granulosa cells of large, viable more follicles showed a high degree of immunoreactivity. In the corpus luteum, all the luteinized cells showed immunoreactivity. No immunoreactivity was detected in other cells of small and large viable follicles. Immunolocalization of P450arom in the equine testicular Leydig cells and in ovarian granulosa and luteinized cells indicates that these cells have the ability to metabolize androgens to estrogens and possibly to catechol estrogens.

  7. Aromatase inhibition by synthetic lactones and flavonoids in human placental microsomes and breast fibroblasts - A comparative study

    SciTech Connect

    Meeuwen, J.A. van Nijmeijer, S.; Mutarapat, T.; Ruchirawat, S.; Jong, P.C. de; Piersma, A.H.; Berg, M. van den

    2008-05-01

    Interference of exogenous chemicals with the aromatase enzyme can be useful as a tool to identify chemicals that could act either chemopreventive for hormone-dependent cancer or adverse endocrine disruptive. Aromatase is the key enzyme in the biosynthesis of steroids, as it converts androgens to estrogens. Certain flavonoids, plant derived chemicals, are known catalytic aromatase inhibitors. Various systems are in use to test aromatase inhibitory properties of compounds. Commonly used are microsomes derived from ovary or placental tissue characterized by high aromatase activity. To a lesser extent whole cell systems are used and specifically cell systems that are potential target tissue in breast cancer development. In this study aromatase inhibitory properties of fadrozole, 8-prenylnaringenin and a synthetic lactone (TM-7) were determined in human placental microsomes and in human primary breast fibroblasts. In addition, apigenin, chrysin, naringenin and two synthetic lactones (TM-8 and TM-9) were tested in human microsomes only. Comparison of the aromatase inhibitory potencies of these compounds between the two test systems showed that the measurement of aromatase inhibition in human placental microsomes is a good predictor of aromatase inhibition in human breast fibroblasts.

  8. Aromatase inhibition by synthetic lactones and flavonoids in human placental microsomes and breast fibroblasts--a comparative study.

    PubMed

    van Meeuwen, J A; Nijmeijer, S; Mutarapat, T; Ruchirawat, S; de Jong, P C; Piersma, A H; van den Berg, M

    2008-05-01

    Interference of exogenous chemicals with the aromatase enzyme can be useful as a tool to identify chemicals that could act either chemopreventive for hormone-dependent cancer or adverse endocrine disruptive. Aromatase is the key enzyme in the biosynthesis of steroids, as it converts androgens to estrogens. Certain flavonoids, plant derived chemicals, are known catalytic aromatase inhibitors. Various systems are in use to test aromatase inhibitory properties of compounds. Commonly used are microsomes derived from ovary or placental tissue characterized by high aromatase activity. To a lesser extent whole cell systems are used and specifically cell systems that are potential target tissue in breast cancer development. In this study aromatase inhibitory properties of fadrozole, 8-prenylnaringenin and a synthetic lactone (TM-7) were determined in human placental microsomes and in human primary breast fibroblasts. In addition, apigenin, chrysin, naringenin and two synthetic lactones (TM-8 and TM-9) were tested in human microsomes only. Comparison of the aromatase inhibitory potencies of these compounds between the two test systems showed that the measurement of aromatase inhibition in human placental microsomes is a good predictor of aromatase inhibition in human breast fibroblasts.

  9. Gossypol enantiomers potently inhibit human placental 3β-hydroxysteroid dehydrogenase 1 and aromatase activities.

    PubMed

    Dong, Yaoyao; Mao, Baiping; Li, Linxi; Guan, Hongguo; Su, Ying; Li, Xiaoheng; Lian, Qingquan; Huang, Ping; Ge, Ren-Shan

    2016-03-01

    Gossypol is a chemical isolated from cotton seeds. It exists as (+) or (-) enantiomer and has been tested for anticancer, abortion-inducing, and male contraception. Progesterone formed from pregnenolone by 3β-hydroxysteroid dehydrogenase 1 (HSD3B1) and estradiol from androgen by aromatase (CYP19A1) are critical for the maintenance of pregnancy or associated with some cancers. In this study we compared the potencies of (+)- and (-)-gossypol enantiomers in the inhibition of HSD3B1 and aromatase activities as well as progesterone and estradiol production in human placental JEG-3 cells. (+) Gossypol showed potent inhibition on human placental HSD3B1 with IC50 value of 2.3 μM, while (-) gossypol weakly inhibited it with IC50 over 100 μM. In contrast, (-) gossypol moderately inhibited CYP19A1 activity with IC50 of 23 μM, while (+) gossypol had no inhibition when the highest concentration (100 μM) was tested. (+) Gossypol enantiomer competitively inhibited HSD3B1 against substrate pregnenolone and showed mixed mode against NAD(+). (-) Gossypol competitively inhibited CYP19A1 against substrate testosterone. Gossypol enantiomers showed different potency related to their inhibition on human HSD3B1 and CYP19A1. Whether gossypol enantiomer is used alone or in combination relies on its application and beneficial effects.

  10. Inhibition of human placental aromatase activity by hydroxylated polybrominated diphenyl ethers (OH-PBDEs)

    SciTech Connect

    Canton, Rocio F. Scholten, Deborah E.A.; Marsh, Goeran; Jong, Paul C. de; Berg, Martin van den

    2008-02-15

    Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in many different polymers, resins and substrates. Due to their widespread production and use, their high binding affinity to particles, and their lipophilic properties, several PBDE congeners can bioaccumulate in the environment. As a result, PBDEs and their hydroxylated metabolites (OH-PBDEs) have been detected in humans and various wildlife samples, such as birds, seals, and whales. Furthermore, certain OH-PBDEs and their methoxylated derivatives (MeO-PBDEs) are natural products in the marine environment. Recently, our laboratory focused on the possible effects on steroidogenesis of PBDEs and OH-PBDEs, e.g. in the human adrenocortical carcinoma (H295R) cell line indicating that some OH-PBDEs can significantly influence steroidogenic enzymes like CYP19 (aromatase) and CYP17. In the present study, human placental microsomes have been used to study the possible interaction of twenty two OH-PBDEs and MeO-PBDEs with aromatase, the enzyme that mediates the conversion of androgens into estrogens. All OH-PBDE derivates showed significant inhibition of placental aromatase activity with IC{sub 50} values in the low micromolar range, while the MeO-PBDEs did not have any effect on this enzyme activity. Enzyme kinetics studies indicated that two OH-PBDEs, 5-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (5-OH-BDE47) and 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE47), had a mixed-type inhibition of aromatase activity with apparent K{sub i}/K{sub i}' of 7.68/0,02 {mu}M and 5.01/0.04 {mu}M respectively. For comparison, some structurally related compounds, a dihydroxylated polybrominated biphenyl, which is a natural product (2,2'-dihyroxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diOH-BB80)) and its non-bromo derivative were also included in the study. Again inhibition of aromatase activity could be measured, but their potency was significantly less than those observed for the OH-PBDEs. These results show

  11. Inhibition of human placental aromatase activity by hydroxylated polybrominated diphenyl ethers (OH-PBDEs).

    PubMed

    Cantón, Rocío F; Scholten, Deborah E A; Marsh, Göran; de Jong, Paul C; van den Berg, Martin

    2008-02-15

    Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants in many different polymers, resins and substrates. Due to their widespread production and use, their high binding affinity to particles, and their lipophilic properties, several PBDE congeners can bioaccumulate in the environment. As a result, PBDEs and their hydroxylated metabolites (OH-PBDEs) have been detected in humans and various wildlife samples, such as birds, seals, and whales. Furthermore, certain OH-PBDEs and their methoxylated derivatives (MeO-PBDEs) are natural products in the marine environment. Recently, our laboratory focused on the possible effects on steroidogenesis of PBDEs and OH-PBDEs, e.g. in the human adrenocortical carcinoma (H295R) cell line indicating that some OH-PBDEs can significantly influence steroidogenic enzymes like CYP19 (aromatase) and CYP17. In the present study, human placental microsomes have been used to study the possible interaction of twenty two OH-PBDEs and MeO-PBDEs with aromatase, the enzyme that mediates the conversion of androgens into estrogens. All OH-PBDE derivates showed significant inhibition of placental aromatase activity with IC(50) values in the low micromolar range, while the MeO-PBDEs did not have any effect on this enzyme activity. Enzyme kinetics studies indicated that two OH-PBDEs, 5-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (5-OH-BDE47) and 6-hydroxy-2,2',4,4'-tetrabromodiphenyl ether (6-OH-BDE47), had a mixed-type inhibition of aromatase activity with apparent K(i)/K(i)' of 7.68/0,02 microM and 5.01/0.04 microM respectively. For comparison, some structurally related compounds, a dihydroxylated polybrominated biphenyl, which is a natural product (2,2'-dihyroxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diOH-BB80)) and its non-bromo derivative were also included in the study. Again inhibition of aromatase activity could be measured, but their potency was significantly less than those observed for the OH-PBDEs. These results show that a

  12. Gas chromatography-mass spectrometric study of 19-oxygenation of the aromatase inhibitor 19-methylandrostenedione with human placental microsomes.

    PubMed

    Numazawa, Mitsuteru; Nagaoka, Masao; Handa, Wakako; Yamada, Akane

    2006-06-01

    To gain insight into the catalytic function of aromatase, we studied 19-oxygenation of 19-methyl-substituted derivative of the natural substrate androstenedione (AD), compound 1, with human placental aromatase by use of gas chromatography-mass spectrometry (GC-MS). Incubation of the 19-methyl derivative 1 with human placental microsomes in the presence of NADPH under an aerobic condition did not yield a detectable amount of [19S]19-hydroxy product 2 or its [19R]-isomer 3 when the product was analyzed as the bis-methoxime-trimethylsilyl (TMS) derivative by GC-MS; moreover, the production of estrogen was not detected as the bis-TMS derivative of estradiol (detection limit: about 3 ng and 10 pg per injection for the 19-ol and estradiol, respectively). The results reveal that the 19-methyl steroid 1 does not serve as a substrate of aromatase, although it does serve as a powerful inhibitor of the enzyme.

  13. Differential Effects of Glyphosate and Roundup on Human Placental Cells and Aromatase

    PubMed Central

    Richard, Sophie; Moslemi, Safa; Sipahutar, Herbert; Benachour, Nora; Seralini, Gilles-Eric

    2005-01-01

    Roundup is a glyphosate-based herbicide used worldwide, including on most genetically modified plants that have been designed to tolerate it. Its residues may thus enter the food chain, and glyphosate is found as a contaminant in rivers. Some agricultural workers using glyphosate have pregnancy problems, but its mechanism of action in mammals is questioned. Here we show that glyphosate is toxic to human placental JEG3 cells within 18 hr with concentrations lower than those found with agricultural use, and this effect increases with concentration and time or in the presence of Roundup adjuvants. Surprisingly, Roundup is always more toxic than its active ingredient. We tested the effects of glyphosate and Roundup at lower nontoxic concentrations on aromatase, the enzyme responsible for estrogen synthesis. The glyphosate-based herbicide disrupts aromatase activity and mRNA levels and interacts with the active site of the purified enzyme, but the effects of glyphosate are facilitated by the Roundup formulation in microsomes or in cell culture. We conclude that endocrine and toxic effects of Roundup, not just glyphosate, can be observed in mammals. We suggest that the presence of Roundup adjuvants enhances glyphosate bioavailability and/or bioaccumulation. PMID:15929894

  14. Differential effects of glyphosate and roundup on human placental cells and aromatase.

    PubMed

    Richard, Sophie; Moslemi, Safa; Sipahutar, Herbert; Benachour, Nora; Seralini, Gilles-Eric

    2005-06-01

    Roundup is a glyphosate-based herbicide used worldwide, including on most genetically modified plants that have been designed to tolerate it. Its residues may thus enter the food chain, and glyphosate is found as a contaminant in rivers. Some agricultural workers using glyphosate have pregnancy problems, but its mechanism of action in mammals is questioned. Here we show that glyphosate is toxic to human placental JEG3 cells within 18 hr with concentrations lower than those found with agricultural use, and this effect increases with concentration and time or in the presence of Roundup adjuvants. Surprisingly, Roundup is always more toxic than its active ingredient. We tested the effects of glyphosate and Roundup at lower nontoxic concentrations on aromatase, the enzyme responsible for estrogen synthesis. The glyphosate-based herbicide disrupts aromatase activity and mRNA levels and interacts with the active site of the purified enzyme, but the effects of glyphosate are facilitated by the Roundup formulation in microsomes or in cell culture. We conclude that endocrine and toxic effects of Roundup, not just glyphosate, can be observed in mammals. We suggest that the presence of Roundup adjuvants enhances glyphosate bioavailability and/or bioaccumulation.

  15. Molecular characterization and expression of equine testicular cytochrome P450 aromatase.

    PubMed

    Seralini, Gilles Eric; Tomilin, Alexey; Auvray, Pierrïck; Nativelle-Serpentini, Celine; Sourdaine, Pascal; Moslemi, Safa

    2003-02-20

    We characterized testicular equine aromatase and its expression. A 2707 bp cDNA was isolated, it encoded a polypeptide of 503 residues with a deduced molecular mass of 57.8 kDa. The sequence features were those of a cytochrome P450 aromatase, with a 78% polypeptide identity with the human counterpart. The gene has a minimal length of 74 kb comprising at least 9 exons and expresses a 2.8 kb mRNA in the testis. Transient cDNA transfections in E293 cells and in vitro translations in a reticulocyte lysate system allowed aromatase protein and activity detections. The activity increased with androstenedione as substrate in a dose-dependent manner. The isolation of testicular aromatase by a new immunoaffinity method demonstrated that the protein could exist either glycosylated or not with a 2 kDa difference. All these results taken together allow new structural studies to progress in the understanding of this cytochrome P450.

  16. Equine cytochrome P450 aromatase exhibits an estrogen 2-hydroxylase activity in vitro.

    PubMed

    Almadhidi, J; Moslemi, S; Drosdowsky, M A; Séralini, G E

    1996-09-01

    Aromatase (estrogen synthetase) is a steroidogenic enzyme complex which catalyzes the conversion of androgens to estrogens (termed aromatization). This enzyme was purified from adult equine testis to homogeneity by five chromatographic steps. The ability of purified and reconstituted equine aromatase to exhibit an estrogen 2-hydroxylase activity was tested and compared to testosterone aromatization. Enzymatic activities were assessed by tritiated water release from labelled estradiol and testosterone. Kinetic analysis of estradiol 2-hydroxylation showed an apparent K(m) of 23 microM and a V(max) of 18 nmol/min/mg, whereas the values for testosterone aromatization were a K(m) of 15.7 nM and a V(max) of 34.6 pmol/min/mg. A specific antiserum raised against purified testicular equine P450arom and known to inhibit aromatase activity [1] was also found to inhibit the estrogen hydroxylase activity of equine placental microsomes in a dose-dependent manner with an IC50 value of 15 microl serum: 0.5 ml incubate. The estrogen hydroxylase activity was inhibited in a dose-dependent manner by two classes of aromatase inhibitors, i.e. steroidal-- (4-hydroxyandrostenedione and 7alpha-([4-aminophenyl]thio)-androst-4-ene-3, 17-dione)--and non-steroidal--(fadrozole and miconazole). The IC50 values were approximately 300 and 890 nM for 4-hydroxyandrostenedione and 7alpha-([4-aminophenyl]thio)-androst-4-ene-3, 17-dione, and 92 and 285 nM, for fadrozole and miconazole, respectively. Furthermore, 4-hydroxyandrostenedione caused a time-dependent inactivation of estrogen hydroxylase activity. We conclude that equine aromatase is able to use estradiol as a substrate, and converts it to catechol estradiol in vitro, possibly using the active site of aromatization. This is the first demonstration that equine aromatase functions as an estrogen 2-hydroxylase, in addition to transforming androgens into estrogen.

  17. A three-dimensional model of aromatase cytochrome P450.

    PubMed Central

    Graham-Lorence, S.; Amarneh, B.; White, R. E.; Peterson, J. A.; Simpson, E. R.

    1995-01-01

    P450 hemeproteins comprise a large gene superfamily that catalyzes monooxygenase reactions in the presence of a redox partner. Because the mammalian members are, without exception, membrane-bound proteins, they have resisted structure-function analysis by means of X-ray crystallographic methods. Among P450-catalyzed reactions, the aromatase reaction that catalyzes the conversion of C19 steroids to estrogens is one of the most complex and least understood. Thus, to better understand the reaction mechanism, we have constructed a three-dimensional model of P450arom not only to examine the active site and those residues potentially involved in catalysis, but to study other important structural features such as substrate recognition and redox-partner binding, which require examination of the entire molecule (excepting the putative membrane-spanning region). This model of P450arom was built based on a "core structure" identified from the structures of the soluble, bacterial P450s (P450cam, P450terp, and P450BM-P) rather than by molecular replacement, after which the less conserved elements and loops were added in a rational fashion. Minimization and dynamic simulations were used to optimize the model and the reasonableness of the structure was evaluated. From this model we have postulated a membrane-associated hydrophobic region of aliphatic and aromatic residues involved in substrate recognition, a redox-partner binding region that may be unique compared to other P450s, as well as residues involved in active site orientation of substrates and an inhibitor of P450arom, namely vorozole. We also have proposed a scheme for the reaction mechanism in which a "threonine switch" determines whether oxygen insertion into the substrate molecule involves an oxygen radical or a peroxide intermediate. PMID:7549871

  18. Perfluorinated chemicals: Differential toxicity, inhibition of aromatase activity and alteration of cellular lipids in human placental cells

    SciTech Connect

    Gorrochategui, Eva; Pérez-Albaladejo, Elisabet; Casas, Josefina; Lacorte, Sílvia; Porte, Cinta

    2014-06-01

    The cytotoxicity of eight perfluorinated chemicals (PFCs), namely, perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorododecanoic acid (PFDoA), perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) was assessed in the human placental choriocarcinoma cell line JEG-3. Only the long chain PFCs – PFOS, PFDoA, PFNA, PFOA – showed significant cytotoxicity in JEG-3 cells with EC50 values in the range of 107 to 647 μM. The observed cytotoxicity was to some extent related to a higher uptake of the longer chain PFCs by cells (PFDoA > PFOS ≫ PFNA > PFOA > PFHxA). Moreover, this work evidences a high potential of PFOS, PFOA and PFBS to act as aromatase inhibitors in placental cells with IC50s in the range of 57–80 μM, the inhibitory effect of PFBS being particularly important despite the rather low uptake of the compound by cells. Finally, exposure of JEG-3 cells to a mixture of the eight PFCs (0.6 μM each) led to a relative increase (up to 3.4-fold) of several lipid classes, including phosphatidylcholines (PCs), plasmalogen PC and lyso plasmalogen PC, which suggests an interference of PFCs with membrane lipids. Overall, this work highlights the ability of the PFC mixture to alter cellular lipid pattern at concentrations well below those that generate toxicity, and the potential of the short chain PFBS, often considered a safe substitute of PFOS, to significantly inhibit aromatase activity in placental cells. - Highlights: • Eight perfluorinated chemicals of different chain lengths have been selected. • Long chain ones – PFOS, PFDoA, PFNA, PFOA – were cytotoxic in placenta cells. • The uptake of long chain perfluorinated chemicals by cells was comparatively higher. • PFOS, PFOA and the short chain PFBS significantly inhibited aromatase activity. • A mixture of perfluorinated chemicals significantly altered placenta cell

  19. Perfluorinated chemicals: differential toxicity, inhibition of aromatase activity and alteration of cellular lipids in human placental cells.

    PubMed

    Gorrochategui, Eva; Pérez-Albaladejo, Elisabet; Casas, Josefina; Lacorte, Sílvia; Porte, Cinta

    2014-06-01

    The cytotoxicity of eight perfluorinated chemicals (PFCs), namely, perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorododecanoic acid (PFDoA), perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) was assessed in the human placental choriocarcinoma cell line JEG-3. Only the long chain PFCs--PFOS, PFDoA, PFNA, PFOA--showed significant cytotoxicity in JEG-3 cells with EC50 values in the range of 107 to 647 μM. The observed cytotoxicity was to some extent related to a higher uptake of the longer chain PFCs by cells (PFDoA>PFOS≫PFNA>PFOA>PFHxA). Moreover, this work evidences a high potential of PFOS, PFOA and PFBS to act as aromatase inhibitors in placental cells with IC50s in the range of 57-80 μM, the inhibitory effect of PFBS being particularly important despite the rather low uptake of the compound by cells. Finally, exposure of JEG-3 cells to a mixture of the eight PFCs (0.6 μM each) led to a relative increase (up to 3.4-fold) of several lipid classes, including phosphatidylcholines (PCs), plasmalogen PC and lyso plasmalogen PC, which suggests an interference of PFCs with membrane lipids. Overall, this work highlights the ability of the PFC mixture to alter cellular lipid pattern at concentrations well below those that generate toxicity, and the potential of the short chain PFBS, often considered a safe substitute of PFOS, to significantly inhibit aromatase activity in placental cells.

  20. Effects of organochlorine compounds on cytochrome P450 aromatase activity in an immortal sea turtle cell line.

    PubMed

    Keller, Jennifer M; McClellan-Green, Patricia

    2004-01-01

    Many classes of environmental contaminants affect the reproductive function of animals through interactions with the endocrine system. The primary components affected by endocrine active compounds (EACs) are the steroid receptors and the enzymes responsible for steroidogenesis. This study sought to develop an in vitro model for assessing EAC effects in sea turtles by examining their ability to alter cytochrome P450 aromatase (CYP19) activity. Aromatase is the enzyme responsible for the conversion of testosterone to estradiol. This enzyme is critical in the sexual differentiation of reptiles which demonstrate temperature-dependent sex determination. An immortal testis cell line GST-TS from a green sea turtle was grown in culture at 30 degrees C in RPMI 1640 media. The cells were exposed to three known aromatase inducers; dexamethasone (Dex), 8Br-cyclic AMP, or human chronic gonadotropin (HCG) and one aromatase inhibitor 4-androstenol-dione (4-OHA). In addition, the GST-TS cells were exposed to 0.1-30 microM atrazine and 3-100 microM 4,4'-DDE. The inducing compounds that have been shown to increase aromatase activity in other systems failed to induce aromatase activity in the GST-TS cells, yet exposure to the inhibiting compound, 4-OHA, did result in a significant reduction. Atrazine (0.1, 1.0 and 10 microM) significantly induced aromatase activity following a 24 h exposure, and 4,4'-DDE inhibited the activity but only at cytotoxic concentrations (100 microM). Based on these results, this in vitro model can be useful in examining the endocrine effects of EACs in sea turtles.

  1. Distinct cytochrome P450 aromatase isoforms in the common carp (Cyprinus carpio): sexual dimorphism and onset of ontogenic expression.

    PubMed

    Barney, Megan L; Patil, Jawahar G; Gunasekera, Rasanthi M; Carter, Chris G

    2008-05-01

    Cytochrome P450 aromatase (CYP19) is a key enzyme in the steroidogenic pathway that catalyses the conversion of testosterone to estrogen, and therefore is thought to influence gonadal sex differentiation. In an effort to understand the role of this enzyme in ovarian differentiation, we isolated cDNA encoding the two distinct isoforms, ovarian and brain (termed cyp19a and cyp19b, respectively) of adult common carp, Cyprinus carpio. The cloned cDNA for cyp19a had an open reading frame (ORF) of 518 amino acid residues, in contrast to cyp19b with an ORF of 511 amino acids. Sequence and phylogenetic analysis showed that these CYP19 isoforms were orthologous with previously described cyp19a and cyp19b from other teleosts. Quantitative real-time PCR indicated that both isoforms are expressed in adult ovary and brain, with predominant expression of cyp19a in the ovary and cyp19b in the brain. The major aromatase expressing tissue was found to be the brain, with greatest cyp19b expression in the anterior quarter (telencephalon) in both sexes. The gonad showed sexually dimorphic expression of both genes and dimorphic expression of cyp19a was observed in the cerebellum and the liver. Ontogenic expression showed that only the ovarian aromatase transcript is inherited maternally, with lower expression observed through early larval development under warmer rearing conditions. The differential and overlapping expression suggests these two aromatase genes have different roles in reproductive physiology.

  2. Gas chromatography-mass spectrometric analysis of oxidative reactions of [19,19-(2)H(2)]19-hydroxy-3-deoxy androgens by placental aromatase. bsence of a deuterium-isotope effect.

    PubMed

    Nagaoka, Masao; Numazawa, Mitsuteru

    2005-11-01

    Aromatase is a cytochrome P-450 enzyme complex that catalyzes the conversion of androst-4-ene-3,17-dione (AD) to estrone through three sequential oxidations of the 19-methyl group. 3-DeoxyAD (1) and its 5-ene isomer 4 are potent and good competitive aromatase inhibitors, which are converted by aromatase to the aldehyde derivatives 3 and 6, respectively, through 19-hydroxy intermediates 2 and 5, respectively. To study the deuterium isotope effect on the conversions of 19-ols 2 and 5 into the corresponding 19-als 3 and 6, we initially synthesized [19,19-(2)H(2)]19-ols 2 and 5 starting from the corresponding non-labeled 19-als 3 and 6 through NaB(2)H(4) reduction of the 19-aldehyde group, followed by oxidation with pyridinium dichromate, and a subsequent NaB(2)H(4) reduction. Approximately 1:1 mixtures of non-labeled (d(0)) and deuterated (d(2)) 19-ols 2 and 5 were separately incubated with human placental microsomes in the presence of NADPH under an air atmosphere, and deuterium contents of the recovered substrates and the 19-aldehyde products were determined by gas chromatography-mass spectrometry. In each experiment, the ratio of d(0) to d(2) of the recovered substrate along with that of d(0) to d(1) of the product were identical to the d(0) to d(2) ratio of the employed substrate irrespective of the incubation time, indicating that the 19-oxygenations of the 3-deoxy steroids 2 and 5 proceeded without a detectable isotope effect, as seen in the aromatization sequence of the natural substrate AD.

  3. Porcine Hypothalamic Aromatase Cytochrome P450: Isoform Characterization, Sex-Dependent Activity, Regional Expression, and Regulation by Enzyme Inhibition in Neonatal Boars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Domestic pigs have three CYP19 genes encoding functional paralogues of the enzyme aromatase cytochrome P450 (P450arom) that are expressed in the gonads, placenta and pre-implantation blastocyst. All catalyze estrogen synthesis, but the “gonadal” type enzyme is unique in also synthesizing a nonaromat...

  4. Potential effect of Olea europea leaves, Sonchus oleraceus leaves and Mangifera indica peel extracts on aromatase activity in human placental microsomes and CYP19A1 expression in MCF-7 cell line: Comparative study.

    PubMed

    Shaban, N Z; Hegazy, W A; Abdel-Rahman, S M; Awed, O M; Khalil, S A

    2016-08-29

    Aromatase inhibitors (AIs) provide novel approaches to the adjuvant therapy for postmenopausal women with estrogen-receptor-positive (ER+) breast cancers. In this study, different plant extracts from Olea europaea leaves (OLE), Sonchus oleraceus L. (SOE) and Mangifera indica peels (MPE) were prepared to identify phytoconstituents and measure antioxidant capacities. The effects of these three extracts on aromatase activity in human placental microsomes were evaluated. Additionally, the effects of these extracts on tissue-specific promoter expression of CYP19A1 gene in cell culture model (MCF-7) were assessed using qRT-PCR. Results showed a concentration-dependent decrease in aromatase activity after treatment with OLE and MPE, whereas, SOE showed a biphasic effect. The differential effects of OLE, SOE and MPE on aromatase expression showed that OLE seems to be the most potent suppressor followed by SOE and then MPE. These findings indicate that OLE has effective inhibitory action on aromatase at both the enzymatic and expression levels, in addition to its cytotoxic effect against MCF-7 cells. Also, MPE may be has the potential to be used as a tissue-specific aromatase inhibitor (selective aromatase inhibitor) and it may be promising to develop a new therapeutic agent against ER+ breast cancer.

  5. Different in vitro metabolism of 7 alpha-methyl-19-nortestosterone by human and equine aromatases.

    PubMed

    Moslemi, S; Dintinger, T; Dehennin, L; Silberzahn, P; Gaillard, J L

    1993-06-01

    The ability of human and equine placental microsomes to aromatize 7 alpha-methyl-19-nortestosterone (MNT) was studied. Kinetic analysis indicates that MNT shares the androgen-binding site of human and equine placental microsomal aromatases. Human placental microsomal estrogen synthetase had about a 2.5-fold higher relative affinity for MNT than the equine placental enzyme (KiMNT/Km androstenedione of 32 versus 87). However, MNT was not metabolized by human placental microsomes, whereas it was very actively metabolized by equine placental microsomes. Further studies using purified equine cytochrome P-450arom indicated that the presence of a 7 alpha-methyl group and the absence of a C19 methyl group did not impair its conversion by the purified enzyme. The product of this reaction was separated and identified as 7 alpha-methylestradiol by gas chromatography coupled to mass spectrometry.

  6. Immunoexpression of aromatase cytochrome P450 and 17β-hydroxysteroid dehydrogenase in women’s ovaries after menopause

    PubMed Central

    2014-01-01

    Background Menopause results in a lack of regular menstrual cycles, leading to the reduction of estrogen production. On the other hand, ovarian androgen synthesis is still present at reduced levels and requires expression of several steroidogenic enzymes. Methods This study was performed on 104 postmenopausal women hospitalized due to uterine leiomyomas, endometriosis, and/or a prolapsed uterus. Patients were divided into three groups depending on the time from menopause. Group A patients experienced menopause 1–5 years before enrollment in the study (42 women). Group B included women who had their last menstruation 5–10 years before the study (40 women). Group C consisted of 22 women who were more than 10 years past menopause. Hysterectomy or removal of the uterine corpus with adnexa was performed during laparotomy. We evaluated the expression of aromatase cytochrome P450 (CYP 19) and 17β-hydroxysteroid dehydrogenase (17β HSD) by employing immunohistochemistry. Results Activity of 17β-HSD and CYP19 was demonstrated in the cytoplasm of stromal cells of postmenopausal ovaries, epithelium cells coating the ovaries, vascular endothelial cells, and epithelial inclusion cysts. However, overall expression of both 17β-HSD and CYP 19 decreased with time after menopause. Conclusion Demonstration of the activity of the key enzymes of ovarian steroidogenesis, CYP 19 and 17β-HSD, confirms steroidogenic activity in the ovaries of postmenopausal women. Nevertheless, ovarian steroidogenic activity decreases with time, and its significant decrease occurs 10 years after menopause. PMID:24855493

  7. A molecular model for the interaction between vorozole and other non-steroidal inhibitors and human cytochrome P450 19 (P450 aromatase).

    PubMed

    Koymans, L M; Moereels, H; Vanden Bossche, H

    1995-06-01

    In a previous study (Vanden Bossche et al., Breast Cancer Res. Treat. 30 (1994) 43) the interaction between (+)-S-vorozole and the I-helix of cytochrome P450 19 (P450 aromatase) has been reported. In the present study we extended the "I-helix model" by incorporating the C-terminus of P450 aromatase. The crystal structures of P450 101 (P450 cam), 102 (P450 BM-3) and 108 (P450 terp) reveal that the C-terminus is structurally conserved and forms part of their respective substrate binding pocket. Furthermore, the present study is extended to the interaction between P450 aromatase and its natural substrate androstenedione and the non-steroidal inhibitors (-)-R-vorozole, (-)-S-fadrozole, R-liarozole and (-)-R-aminoglutethimide. It is found that (+)-S-vorozole, (-)-S-fadrozole and R-liarozole bind in a comparable way to P450 aromatase and interact with both the I-helix (Glu302 and Asp309) and C-terminus (Ser478 and His480). The weak activity of (-)-R-aminoglutethimide might be attributed to a lack of interaction with the C-terminus.

  8. Competitive product inhibition of aromatase by natural estrogens.

    PubMed

    Shimizu, Y; Yarborough, C; Osawa, Y

    1993-03-01

    In order to better understand the function of aromatase, we carried out kinetic analyses to assess the ability of natural estrogens, estrone (E1), estradiol (E2), 16 alpha-OHE1, and estriol (E3), to inhibit aromatization. Human placental microsomes (50 micrograms protein) were incubated for 5 min at 37 degrees C with [1 beta-3H]testosterone (1.24 x 10(3) dpm 3H/ng, 35-150 nM) or [1 beta-3H,4-14C]androstenedione (3.05 x 10(3) dpm 3H/ng, 3H/14C = 19.3, 7-65 nM) as substrate in the presence of NADPH, with and without natural estrogens as putative inhibitors. Aromatase activity was assessed by tritium released to water from the 1 beta-position of the substrates. Natural estrogens showed competitive product inhibition against androgen aromatization. The Ki of E1, E2, 16 alpha-OHE1, and E3 for testosterone aromatization was 1.5, 2.2, 95, and 162 microM, respectively, where the Km of aromatase was 61.8 +/- 2.0 nM (n = 5) for testosterone. The Ki of E1, E2, 16 alpha-OHE1, and E3 for androstenedione aromatization was 10.6, 5.5, 252, and 1182 microM, respectively, where the Km of aromatase was 35.4 +/- 4.1 nM (n = 4) for androstenedione. These results show that estrogen inhibit the process of androgen aromatization and indicate that natural estrogens regulate their own synthesis by the product inhibition mechanism in vivo. Since natural estrogen binds to the active site of human placental aromatase P-450 complex as competitive inhibitors, natural estrogens might be further metabolized by aromatase. This suggests that human placental estrogen 2-hydroxylase activity is catalyzed by the active site of aromatase cytochrome P-450 and also agrees with the fact that the level of catecholestrogens in maternal plasma increases during pregnancy. The relative affinities and concentration of androgens and estrogens would control estrogen and catecholestrogen biosynthesis by aromatase.

  9. Inhibition of human estrogen synthetase (aromatase) by flavones.

    PubMed

    Kellis, J T; Vickery, L E

    1984-09-07

    Several naturally occurring and synthetic flavones were found to inhibit the aromatization of androstenedione and testosterone to estrogens catalyzed by human placental and ovarian microsomes. These flavones include (in order of decreasing potency) 7,8-benzoflavone, chrysin, apigenin, flavone, flavanone, and quercetin; 5,6-benzoflavone was not inhibitory. 7,8-Benzoflavone and chrysin were potent competitive inhibitors and induced spectral changes in the aromatase cytochrome P-450 indicative of substrate displacement. Flavones may thus compete with steroids in their interaction with certain monooxygenases and thereby alter steroid hormone metabolism.

  10. Structural basis for androgen specificity and oestrogen synthesis in human aromatase

    SciTech Connect

    Ghosh, Debashis; Griswold, Jennifer; Erman, Mary; Pangborn, Walter

    2009-03-06

    Aromatase cytochrome P450 is the only enzyme in vertebrates known to catalyse the biosynthesis of all oestrogens from androgens. Aromatase inhibitors therefore constitute a frontline therapy for oestrogen-dependent breast cancer. In a three-step process, each step requiring 1 mol of O{sub 2}, 1 mol of NADPH, and coupling with its redox partner cytochrome P450 reductase, aromatase converts androstenedione, testosterone and 16{alpha}-hydroxytestosterone to oestrone, 17{beta}-oestradiol and 17{beta},16{alpha}-oestriol, respectively. The first two steps are C19-methyl hydroxylation steps, and the third involves the aromatization of the steroid A-ring, unique to aromatase. Whereas most P450s are not highly substrate selective, it is the hallmark androgenic specificity that sets aromatase apart. The structure of this enzyme of the endoplasmic reticulum membrane has remained unknown for decades, hindering elucidation of the biochemical mechanism. Here we present the crystal structure of human placental aromatase, the only natural mammalian, full-length P450 and P450 in hormone biosynthetic pathways to be crystallized so far. Unlike the active sites of many microsomal P450s that metabolize drugs and xenobiotics, aromatase has an androgen-specific cleft that binds the androstenedione molecule snugly. Hydrophobic and polar residues exquisitely complement the steroid backbone. The locations of catalytically important residues shed light on the reaction mechanism. The relative juxtaposition of the hydrophobic amino-terminal region and the opening to the catalytic cleft shows why membrane anchoring is necessary for the lipophilic substrates to gain access to the active site. The molecular basis for the enzyme's androgenic specificity and unique catalytic mechanism can be used for developing next-generation aromatase inhibitors.

  11. Structural basis for androgen specificity and oestrogen synthesis in human aromatase.

    PubMed

    Ghosh, Debashis; Griswold, Jennifer; Erman, Mary; Pangborn, Walter

    2009-01-08

    Aromatase cytochrome P450 is the only enzyme in vertebrates known to catalyse the biosynthesis of all oestrogens from androgens. Aromatase inhibitors therefore constitute a frontline therapy for oestrogen-dependent breast cancer. In a three-step process, each step requiring 1 mol of O(2), 1 mol of NADPH, and coupling with its redox partner cytochrome P450 reductase, aromatase converts androstenedione, testosterone and 16alpha-hydroxytestosterone to oestrone, 17beta-oestradiol and 17beta,16alpha-oestriol, respectively. The first two steps are C19-methyl hydroxylation steps, and the third involves the aromatization of the steroid A-ring, unique to aromatase. Whereas most P450s are not highly substrate selective, it is the hallmark androgenic specificity that sets aromatase apart. The structure of this enzyme of the endoplasmic reticulum membrane has remained unknown for decades, hindering elucidation of the biochemical mechanism. Here we present the crystal structure of human placental aromatase, the only natural mammalian, full-length P450 and P450 in hormone biosynthetic pathways to be crystallized so far. Unlike the active sites of many microsomal P450s that metabolize drugs and xenobiotics, aromatase has an androgen-specific cleft that binds the androstenedione molecule snugly. Hydrophobic and polar residues exquisitely complement the steroid backbone. The locations of catalytically important residues shed light on the reaction mechanism. The relative juxtaposition of the hydrophobic amino-terminal region and the opening to the catalytic cleft shows why membrane anchoring is necessary for the lipophilic substrates to gain access to the active site. The molecular basis for the enzyme's androgenic specificity and unique catalytic mechanism can be used for developing next-generation aromatase inhibitors.

  12. Effects of Methoxychlor and Its Metabolite Hydroxychlor on Human Placental 3β-Hydroxysteroid Dehydrogenase 1 and Aromatase in JEG-3 Cells.

    PubMed

    Liu, Shiwen; Mao, Baiping; Bai, Yanfang; Liu, Jianpeng; Li, Huitao; Li, Xiaoheng; Lian, Qingquan; Ge, Ren-Shan

    2016-01-01

    Progesterone and estradiol produced by the human placenta are critical for maintenance of pregnancy and fetal development. In the human placenta, 3β-hydroxysteroid dehydrogenase 1 (HSD3B1) is responsible for the formation of progesterone from pregnenolone and aromatase (CYP19A1) for the production of estradiol from androgen. Insecticide methoxychlor (MXC) and its metabolite hydroxychlor (HPTE) may disrupt the activities of these 2 enzymes. In this study, we investigated the effects of MXC and HPTE on steroid production in human placental JEG-3 cells and on HSD3B1 and CYP19A1 activities. MXC and HPTE inhibited progesterone and estradiol production in JEG-3 cells. MXC and HPTE were potent HSD3B1 inhibitors with the half maximal inhibitory concentration (IC50) values of 2.339 ± 0.096 and 1.918 ± 0.078 μmol/l, respectively. MXC had no inhibition on CYP19A1 at 100 μmol/l, while HPTE was a weak inhibitor with IC50 of 97.16 ± 0.10 μmol/l. When pregnenolone was used to determine the inhibitory mode, MXC and HPTE were found to be competitive inhibitors of HSD3B1. When cofactor NAD+ was used, MXC and HPTE were the noncompetitive inhibitors of HSD3B1. When testosterone was used, HPTE was a mixed inhibitor of CYP19A1. In conclusion, MXC and HPTE are potent inhibitors of human HSD3B1, and HPTE is a weak CYP19A1 inhibitor.

  13. Modulation of cytochromes P450 with xanthone-based molecules: from aromatase to aldosterone synthase and steroid 11β-hydroxylase inhibition.

    PubMed

    Gobbi, Silvia; Hu, Qingzhong; Negri, Matthias; Zimmer, Christina; Belluti, Federica; Rampa, Angela; Hartmann, Rolf W; Bisi, Alessandra

    2013-02-28

    Imidazolylmethylflavones previously reported by us as aromatase inhibitors proved to be able to interact with aldosterone synthase (CYP11B2), a cytochrome P450 enzyme involved in the biosynthesis of the mineralcorticoid hormone aldosterone, and were used to obtain a pharmacophore model for this enzyme. Here, in the search for potential ligands for CYP11B2 and the related CYP11B1, a virtual screening of a small compounds library of our earlier synthesized aromatase inhibitors was performed and, according to the results and the corresponding biological data, led to the design and synthesis of a series of xanthones derivatives carrying an imidazolylmethyl substituent in position 1 and different substituents in position 4. Some very potent inhibitors were obtained; in particular, the 4-chlorine derivative was active in the low nanomolar or subnanomolar range on CYP11B2 and CYP11B1, respectively, proving that xanthone can be considered as an excellent scaffold, whose activity can be directed to different targets when appropriately functionalized.

  14. Steroidal inhibitors as chemical probes of the active site of aromatase.

    PubMed

    Brueggemeir, R W; Moh, P P; Ebrahimian, S; Darby, M V

    1993-03-01

    Androstenedione analogs containing 7 alpha-substituents have proven to be potent inhibitors of aromatase in human placental microsomes, in MCF-7 mammary cell cultures, and in JAr choriocarcinoma cells. Recent investigations have focused on the use of mechanism-based inhibitors, such as 7 alpha-substituted 1,4-androstadienediones, to biochemically probe the active site of aromatase. Inhibition kinetics were determined under initial velocity conditions using purified human placental cytochrome P450arom protein in a reconstituted system. Derivatives of 1,4-androstadiene-3,17-dione and 1,4,6-androstatriene-3,17-dione exhibited high affinity in the purified enzyme system. 7 alpha-(4'-Amino)phenylthio-1,4-androstadiene-3,17-dione, abbreviated 7 alpha-APTADD, demonstrated rapid time-dependent, first-order inactivation of reconstituted aromatase activity only in the presence of NADPH. The apparent Kinact for 7 alpha-APTADD is 11.8 nM, the first-order rate of inactivation is 2.72 x 10(-3) sec-1, and the half-time of inactivation at infinite inhibitor concentration is 4.25 min. The values for the rate constant and half-time of inactivation are similar to those observed in the placental microsomal assay system. Further studies were performed with radioiodinated 7 alpha-(4'-iodo)phenylthio-1,4-androstadienedione, 7 alpha-IPTADD, and the reconstituted aromatase system. Incubations with [125I] 7 alpha-IPTADD were followed by protein precipitation, solvent extraction, and column chromatography. Analysis of the isolated cytochrome P450arom by gel electrophoresis and autoradiography demonstrated the presence of only one radioactive band, which corresponded to the protein staining band for cytochrome P450arom. HPLC radiochromatographic analysis of the isolated cytochrome P450aroM confirmed the presence of only one radioactive peak coeluting with the u.v. peak for cytochrome P450arom. Peptide mapping analysis by reverse-phase HPLC of digested inhibitor-cytochrome P450arom complex

  15. Pharmacological concentration of resveratrol suppresses aromatase in JEG-3 cells.

    PubMed

    Wang, Yun; Leung, Lai K

    2007-09-28

    Estrogen is crucial in preparing of pregnancy, and its role in the maintenance of pregnancy has yet to be elucidated. During the course of pregnancy, the placenta is responsible for the provision of estrogen. The hormone biosynthesis is catalyzed by cytochrome P450 (CYP) 19 or aromatase. In the present study, we screened several common dietary components and identified the grape polyphenol resveratrol to be a potential inhibitor in the hormone synthesis. In a recombinant protein system resveratrol inhibited the aromatase activity with an IC(50) value of approximately 40 microM. Subsequent analysis was performed in the human placental JEG-3 cells, and 25 microM resveratrol significantly reduced the mRNA abundance in these cells. Since the transcriptional control of CYP19 gene is tissue-specific and the proximal promoter region of exon Ia has previously been shown to be crucial in CYP19 expression in placental cells, we also evaluated the promoter activity of this gene. Reporter gene assays revealed that resveratrol repressed the transcriptional control of promoter Ia. The present study illustrated the possibility that dietary supplementation of resveratrol interfered with the normal functioning of placental cells.

  16. Characterization and expression profile of the ovarian cytochrome P-450 aromatase (cyp19A1) gene during thermolabile sex determination in Pejerrey, Odontesthes bonariensis

    USGS Publications Warehouse

    Karube, M.; Fernandino, J.I.; Strobl-Mazzulla, P.; Strussmann, C.A.; Yoshizaki, G.; Somoza, G.M.; Patino, R.

    2007-01-01

    Cytochrome P450 aromatase (cyp19) is an enzyme that catalyzes the conversion of androgens to estrogens and may play a role in temperature- dependent sex determination (TSD) of reptiles, amphibians, and fishes. In this study, the ovarian P450 aromatase form (cyp19A1) of pejerrey Odontesthes bonariensis, a teleost with marked TSD, was cloned and its expression profile evaluated during gonadal differentiation at feminizing (17??C, 100% females), mixed-sex producing (24 and 25??C, 73.3 and 26.7% females, respectively), and masculinizing (29??C, 0% females) temperatures. The deduced cyp19A1 amino acid sequence shared high identity (>77.8%) with that from other teleosts but had low identity (<61.8%) with brain forms (cyp19A2), including that of pejerrey itself. The tissue distribution analysis of cyp19A1 mRNA in adult fish revealed high expression in the ovary. Semi-quantitative reverse transcription polymerase chain reaction analysis of the bodies of larvae revealed that cyp19A1 expression increased before the appearance of the first histological signs of ovarian differentiation at the feminizing temperature but remained low at the masculinizing temperature. The expression levels at mixed-sex producing temperatures were bimodal rather than intermediate, showing low and high modal values similar to those at the feminizing and masculinizing temperatures, respectively. The population percentages of high and low expression levels at intermediate temperatures were proportional to the percentage of females and males, respectively, and high levels were first observed at about the time of sex differentiation of females. These results suggest that cyp19A1 is involved in the process of ovarian formation and possibly also in the TSD of pejerrey. ?? 2007 Wiley-Liss, Inc.

  17. Metabolic aspects of the 1 beta-proton and the 19-methyl group of androst-4-ene-3,6,17-trione during aromatization by placental microsomes and inactivation of aromatase.

    PubMed

    Numazawa, M; Midzuhashi, K; Nagaoka, M

    1994-02-11

    Aromatase catalyzes the conversion of androst-4-ene-3,17-dione to estrogen through sequential oxygenations at the 19-methyl group. Androst-4-ene-3,6,17-trione (AT) is a suicide substrate of aromatase, and the mechanism of inactivation of aromatase has been postulated to involve enzymatic oxygenation at the 19-position. [1 beta-3H,4-14C]-, [19-3H3,4-14C]-, and [1 beta-3H,19-14C]ATs, with high specific activities, were synthesized to study metabolic aspects and the inactivation mechanism. Incubation of the labeled AT with human placental microsomes yielded the 19-oxygenated derivatives, 19-hydroxy-AT and 19-oxo-AT, as well as the aromatization products, 6-oxoestrone and 6-oxoestradiol. A stereospecific 1 beta-proton elimination occurred during the aromatization of [1 beta-3H,4-14C]AT, and a marked tritium isotope effect was observed in the first hydroxylation at C-19 of [19-3H3,4-14C]AT. After incubation of the three double-labeled ATs, the solubilized proteins were subjected to SDS-PAGE and the 3H/14C ratio of the aromatase-bound metabolite in a 46-69 kDa fraction was analyzed. A marked decrease of the 3H/14C ratio of the metabolite was observed in the experiment using [19-3H3,4-14C]AT, compared with that of the labeled AT used, but there were no significant changes in the other experiments, indicating that the adduct retains the 1 beta-proton, the 19-carbon, and one of the three 19-methyl protons of AT. Thus, we conclude that further oxygenation of 19-oxo-AT produced by the two initial hydroxylations of AT at C-19 yields not only 6-oxoestrogen (by a mechanism similar to that involved in the aromatization of the natural substrate) but also a reactive electrophile that immediately binds to the active site in an irreversible manner, resulting in inactivation of aromatase.

  18. Expression of two cytochrome P450 aromatase genes is regulated by endocrine disrupting chemicals in rare minnow Gobiocypris rarus juveniles.

    PubMed

    Wang, Jingjing; Liu, Xiaolin; Wang, Houpeng; Wu, Tingting; Hu, Xiaoqi; Qin, Fang; Wang, Zaizhao

    2010-09-01

    To elucidate the effects of endocrine disrupting chemicals (EDCs) on aromatase, the rare minnow ovarian and brain P450 aromatase (cyp19a1a and cyp19a1b) cDNA and their 5'-flanking regions were isolated and characterized. RT-PCR analysis revealed that the rare minnow cyp19a1a mRNA was predominantly expressed in ovary while cyp19a1b was predominantly expressed in brain. Sequences for binding sites of steroidogenic factor-1, peroxisome proliferators-activated receptor, aryl hydrocarbon receptor, CCAAT/enhancer binding protein, estrogen responsive element, glucocorticoid responsive element, and retinoic acid receptor were identified on promoter regions of cyp19a1 genes. The influence of several EDCs on the transcript abundance of cyp19a1a and cyp19a1b was investigated in rare minnow juveniles. Clofibrate did not influence the expression of either cyp19a1 genes. Exposure to 1nM ethinylestradiol (EE2) for 3days significantly downregulated the expression of cyp19a1a gene, however 0.1 and 1 nM EE2 significantly increased the gene expression of cyp19a1b. Exposure to 100 and 1000 nM 4-nonylphenol (NP) significantly suppressed the cyp19a1a expression, but it had no effect on the expression of cyp19a1b gene. Bisphenol A (BPA) strongly suppressed the cyp19a1b gene expression from 0.1 to 10 nM and significantly suppressed the gene expression of cyp19a1a only at 10 nM. These results indicate that EDCs may influence the expression of cyp19a1 genes through differential transcriptional modulation in rare minnow juveniles.

  19. Synthesis and evaluation of benzoxazolinonic imidazoles and derivatives as non-steroidal aromatase inhibitors.

    PubMed

    Nativelle-Serpentini, Celine; Moslemi, Safa; Yous, Said; Park, Chang Ha; Lesieur, Daniel; Sourdaine, Pascal; Séralini, Gilles-Eric

    2004-04-01

    New compounds were tested in vitro on aromatase activity in human placental and equine testicular microsomes. Equine aromatase, very well characterized biochemically, is used as a comparative model to understand the mechanism of aromatase inhibition. Among 15 molecules screened, 5 of them (11-15) strongly inhibit human and equine aromatases with IC50 values ranging from 13-85nM and from 23-103nM respectively. These results were corroborated by Ki/Km values. Moreover, spectral studies showed a type II spectrum with both enzymes, which is characteristic of an interaction between the nitrogen atom of the molecule and the heme of the cytochrome P450. Compound 12, which has the lowest IC50 and Ki/Km ratio, inactivates aromatase in a dose and time-dependent manner. This might be very important for the treatment of estrogen-dependent diseases such as breast cancer. Finally, MTT assays on E293 cells revealed that the molecules were not cytotoxic.

  20. Suppression of human cytochrome P450 aromatase activity by monoclonal and recombinant antibody fragments and identification of a stable antigenic complex.

    PubMed

    Lala, Puloma; Higashiyama, Tadayoshi; Erman, Mary; Griswold, Jennifer; Wagner, Traci; Osawa, Yoshio; Ghosh, Debashis

    2004-03-01

    Human cytochrome P450 aromatase (P450arom) is responsible for biosynthesis of estrogens from androgens. Monoclonal antibody MAb3-2C2 to P450arom specifically binds to a conformational epitope and suppresses the enzyme activity in a dose-dependent manner. The crystal structure of the Fab fragment of MAb3-2C2 has been used to engineer a recombinant single chain antibody fragment (scFv) and a homodimeric variable domain of the light chain (VL(2)). These recombinant antibody fragments have been expressed in Escherichia coli and purified. Here, we show that the recombinant scFv suppresses P450arom activity with an IC(50) value similar to that of natural MAb3-2C2 F(ab')(2). The recombinant VL(2) also exhibits dose-dependent suppression of the P450arom activity, but at a reduced level, demonstrating that the homodimer is unable to fully mimic the complementarity determining region (CDR) of a variable heavy chain (VH)-VL heterodimer. We prepare and purify a stable complex of P450arom with MAb3-2C2 F(ab')(2) and show that the complex migrates and precipitates as a single molecular assembly. Efforts to crystallize P450arom for structure-function studies have yielded small single crystals. Our results suggest that formation of stable complexes with fragments of the monoclonal antibody could provide an alternative method for crystallization of P450arom.

  1. [Exon 5 alternative splicing of the cytochrome P450 aromatase could be a regulatory mechanism for estrogen production in humans].

    PubMed

    Pepe, Carolina M; Saraco, Nora I; Baquedano, María Sonia; Guercio, Gabriela; Vaiani, Elisa; Berensztein, Esperanza; Rivarola, Marco A; Belgorosky, Alicia

    2007-01-01

    P450 aromatase (P450Aro), involved in androgen to estrogen conversion, is encoded by the CYP19 gene. P450Aro c655G>A mutation described in heterozygous form in a girl and in homozygous form in an adult male with P450Aro deficiency results in an aberrant splicing due to disruption of a donor splice site. A truncated inactive protein would be expected if intron5 is retained. Surprisingly, the girl described with this mutation showed spontaneous breast development and pubertal estradiol (E2) levels suggesting residual P450Aro activity (AA). Formerly, we postulate the in frame E5 skipping as a consequence of this mutation generating a protein with some degree of activity. When P450Aro mRNA expression was analysed from patient's lymphocytes, an aberrant spliced mRNA lacking E5 (-E5mRNA) was detected, suggesting an association between E5 skipping and the presence of the mutation. Splicing assays in Y1 cells confirmed this association. -Ex5 cDNA expression in Y1 cells resulted in an inactive protein that could not explain patient's phenotype. Exon 5 might be predicted as a poorly defined exon suggesting a susceptibility to splicing mutations and physiological alternative splicing (AS) events. Therefore, -Ex5mRNA was assessed as a natural occurring alternative transcript in normal human steroidogenic tissues. As P450Aro -E5mRNA expression was detected in human term placenta, prepubertal testis and prepubertal adrenal, we might speculate that AS of P450Aro coding region would occur in humans and would be involved in the complex AA regulation. Furthermore, tissue specific regulation of AS might suggest low expression of +E5mRNA from the c655G>A allele explaining residual AA evidenced in the affected girl.

  2. Immunolocalization of androgen receptor, aromatase cytochrome P450, estrogen receptor alpha and estrogen receptor beta proteins during the breeding season in scent glands of muskrats (Ondatra zibethicus).

    PubMed

    Lu, Lu; Zhang, Haolin; Lv, Na; Ma, Xiaoting; Tian, Long; Hu, Xiao; Liu, Shuqiang; Xu, Meiyu; Weng, Qiang; Watanabe, Gen; Taya, Kazuyoshi

    2011-10-01

    Aromatase cytochrome P450 (P450arom) is an enzyme that catalyzes the conversion of androgen to estrogen. Expression of P450arom in extra-gonadal sites and locally-synthesized estrogen play an important role in physiological conditions. The purpose of this study was to investigate the cellular immunolocalization of androgen receptor (AR), P450arom, estrogen receptor alpha (ERa) and estrogen receptor beta (ERβ) in muskrat scent glands during the breeding season. Histological observation and immunohistochemistry of AR, P450arom, ERa and ERβ were performed in the muskrat scent glands. In addition, total proteins were extracted from scent glandular tissues in the breeding season and were used for Western blotting analysis for AR, P450arom, ERα and ERβ. Histologically, glandular cells, interstitial cells, epithelial cells of the excretory duct and the excretory tubules were identified in the muskrat scent glands during the breeding season. AR was only observed in glandular cells of scent glands; P450arom was expressed in glandular cells and epithelial cells of the excretory duct; ERα was found in glandular cells, interstitial cells and epithelial cells of the excretory duct, whereas ERβ was present in glandular cells and epithelial cells of the excretory duct. Also, the positive signals of AR, P450arom, ERα and ERβ by Western blotting were all observed in scent glandular tissues. These results suggested that the scent gland is the target organ of androgens and estrogens, and that estrogens may play an important autocrine or paracrine role in glandular function of the muskrats.

  3. Ovarian expression of inhibin-subunits, 3β-hydroxysteroid dehydrogenase, and cytochrome P450 aromatase during the estrous cycle and pregnancy of shiba goats (Capra hircus).

    PubMed

    Kandiel, Mohamed M M; Watanabe, Gen; Taya, Kazuyoshi

    2010-01-01

    The cellular localization of the inhibin subunits (α, β(A), and β (B)), steroidogenic enzymes (3β-hydroxysteroid dehydrogenase (3βHSD) and cytochrome P450 aromatase (P450arom) were evaluated in the ovaries of cyclic (n=6) and pregnant (n=2) Shiba goats (Capra Hircus). The immunointensity of inhibin α and β(A) subunits showed an increase in the granulosa cells (GC) of developing follicles. Inhibin β(B) subunit and P450arom showed high expression in GC of antral follicles. 3βHSD immunoreactivity was uniform in preantral and antral follicles. In follicular phase and late pregnancy, there was a strong expression of inhibin α subunit in GC of antral follicles. Although in mid pregnancy, antral follicles GC showed moderate immunostaining of inhibin β subunits, the immunoreactivity of inhibin β(A) and β(B) subunits was high during the follicular and luteal stages, respectively. While, immunoreactivity of GC to P450arom was moderate during all studied stages, and 3βHSD immunoreactivity was plentiful in antral follicles during the luteal phase. The immunoreactivity to inhibin α subunit and P450arom was abundant during mid pregnancy in the luteal tissues. Immunoreaction to inhibin β subunits was faint-to-moderate in cyclic and pregnancy corpora lutea. Immunoexpression of 3βHSD was maximal in late pregnancy corpora lutea. The present results suggest that, in goats, the GC of antral follicles are the main source of dimeric inhibins and that corpora lutea may partially participate in the secretion of inhibin. Changes in ovarian hormonal levels might depend on the synthesizing capacity of hormones in the follicles and corpora lutea to regulate the goat's reproductive stages.

  4. Control of oestradiol secretion and of cytochrome P450 aromatase messenger ribonucleic acid accumulation by FSH involves different intracellular pathways in oestrogenic bovine granulosa cells in vitro.

    PubMed

    Silva, J M; Hamel, M; Sahmi, M; Price, C A

    2006-12-01

    The objective of this study was to determine the major intracellular signalling pathways used by FSH and insulin to stimulate cytochrome P450 aromatase (Cyp19) mRNA and oestradiol accumulation in oestrogenic bovine granulosa cells in vitro. Bovine granulosa cells from small follicles (2-4 mm diameter) were cultured for 6 days under non-luteinizing conditions in the presence of insulin at 100 ng/ml, or insulin (10 ng/ml) and FSH (1 ng/ml). On day 4 of culture, specific inhibitors of phosphatidylinositol 3-kinase (PI3K; LY-294002), protein kinase C (PKC; GF-109203X), protein kinase A (PKA; H-89) or mitogen-activated protein (MAP) kinase activation (PD-98059) were added. The addition of PI3K and PKC inhibitors, but not of PKA inhibitor, significantly decreased insulin-stimulated Cyp19 mRNA levels and oestradiol accumulation (P < 0.001). The PKA inhibitor significantly decreased FSH-stimulated Cyp19 mRNA abundance and oestradiol secretion, whereas PI3K and PKC inhibitors decreased oestradiol secretion without affecting Cyp19 mRNA accumulation. Inhibition of MAP kinase pathway significantly increased Cyp19 mRNA abundance in insulin- and FSH-stimulated cells. P450scc mRNA levels and progesterone secretion were not affected by any inhibitor in either experiment. Although FSH stimulates Cyp19 expression predominantly through PKA, oestradiol secretion is altered by PI3K and PKC pathways independently of Cyp19 mRNA levels. In addition, we suggest that Cyp19 is under tonic inhibition mediated through a MAP kinase pathway.

  5. Binding characteristics of aromatase inhibitors and phytoestrogens to human aromatase.

    PubMed

    Chen, S; Kao, Y C; Laughton, C A

    1997-04-01

    We have evaluated the binding characteristics of three steroidal inhibitors [4-hydroxyandrostenedione (4-OHA), 7alpha-(4'-amino)phenylthio-1,4-androstadiene-3,17-dione (7alpha-APTADD), and bridge (2,19-methyleneoxy) androstene-3,17-dione (MDL 101,003)], four nonsteroidal inhibitors [aminoglutethimide (AG), CGS 20267, ICI D1033, and vorozole (R83842)], and two flavone phytoestrogens (chrysin, and 7,8-dihydroxyflavone) to aromatase through a combination of computer modeling and inhibitory profile studies on the wild-type and six aromatase mutants (I133Y, P308F, D309A, T310S, I395F, and I474Y). We have generated two aromatase models based on the x-ray structures of cytochrome P450-cam and cytochrome P450bm3, respectively. A major difference between the cytochrome P450cam-based and cytochrome P450bm3-based models is in the predicted lengths of helices F and G. In the cytochrome P450cam-based model, helices F and G lie antiparallel and extend across the active-site face of the molecule from one edge to the center, so that the carboxyl-terminal residues of helix F and the N-terminal residues of helix G make a major contribution to the structure of the active site. In the cytochrome P450bm3-based model, both helices are longer and so extend almost all the way across the active-site face of the molecule. Considering the size of the androgen substrate, we evaluated our results mainly based on the cytochrome P450cam model. The mutations involved in this study are thought to be at or near the proposed active site pocket. The inhibitory profile analysis has produced very interesting results and provided a molecular basis as to how seven aromatase inhibitors with different structures bind to the active site of aromatase. Furthermore, the investigation reveals that phytoestrogens bind to the active site of aromatase in a different orientation from that in the estrogen receptor.

  6. Discovery of a new class of cinnamyl-triazole as potent and selective inhibitors of aromatase (cytochrome P450 19A1).

    PubMed

    McNulty, James; Keskar, Kunal; Crankshaw, Denis J; Holloway, Alison C

    2014-09-15

    Synthesis of a novel class of natural product inspired cinnamyl-containing 1,4,5-triazole and the potent inhibition of human aromatase (CYP 450 19A1) by select members is described. Structure-activity data generated provides insights into the requirements for potency particularly the inclusion of an aryl bromide or chloride residue as a keto-bioisostere.

  7. Effects of Neonicotinoids on Promoter-Specific Expression and Activity of Aromatase (CYP19) in Human Adrenocortical Carcinoma (H295R) and Primary Umbilical Vein Endothelial (HUVEC) Cells.

    PubMed

    Caron-Beaudoin, Élyse; Denison, Michael S; Sanderson, J Thomas

    2016-01-01

    The enzyme aromatase (CYP19; cytochrome P450 19) in humans undergoes highly tissue- and promoter-specific regulation. In hormone-dependent breast cancer, aromatase is over-expressed via several normally inactive promoters (PII, I.3, I.7). Aromatase biosynthesizes estrogens, which stimulate breast cancer cell proliferation. The placenta produces estrogens required for healthy pregnancy and the major placental CYP19 promoter is I.1. Exposure to certain pesticides, such as atrazine, is associated with increased CYP19 expression, but little is known about the effects of neonicotinoid insecticides on CYP19. We developed sensitive and robust RT-qPCR methods to detect the promoter-specific expression of CYP19 in human adrenocortical carcinoma (H295R) and primary umbilical vein endothelial (HUVEC) cells, and determined the potential promoter-specific disruption of CYP19 expression by atrazine and the commonly used neonicotinoids imidacloprid, thiacloprid, and thiamethoxam. In H295R cells, atrazine concentration-dependently increased PII- and I.3-mediated CYP19 expression and aromatase catalytic activity. Thiacloprid and thiamethoxam induced PII- and I.3-mediated CYP19 expression and aromatase activity at relatively low concentrations (0.1-1.0 µM), exhibiting non-monotonic concentration-response curves with a decline in gene induction and catalytic activity at higher concentrations. In HUVEC cells, atrazine slightly induced overall (promoter-indistinct) CYP19 expression (30 µM) and aromatase activity (≥ 3 µM), without increasing I.1 promoter activity. None of the neonicotinoids increased CYP19 expression or aromatase activity in HUVEC cells. Considering the importance of promoter-specific (over)expression of CYP19 in disease (breast cancer) or during sensitive developmental periods (pregnancy), our newly developed RT-qPCR methods will be helpful tools in assessing the risk that neonicotinoids and other chemicals may pose to exposed women.

  8. Aromatase gene expression in the stallion.

    PubMed

    Lemazurier, E; Sourdaine, P; Nativelle, C; Plainfossé, B; Séralini, G

    2001-06-10

    Adult stallion secretes very high estrogen levels in its testicular vein and semen, and the responsible enzyme cytochrome P450 aromatase (P450 arom) is known to be present mainly in Leydig cells. We studied in further details the distribution of equine aromatase in various adult tissues including the brain (hypothalamic area), liver, kidney, small intestine, muscle, bulbourethral gland and testes. The aromatase mRNA was essentially detected by RT-PCR in testis (169+/-14 amol of aromatase mRNA per microg of total RNA) and was barely detectable in brain, or below 0.1 amol/microg RNA in other tissues. This range of expression was confirmed by ELISA (50+/-7 pg/microg total protein) in the testis, and by immunoblot, evidencing a 53 kDA specific protein band in testis and brain only. The corresponding aromatase activity was well detected, by 3H(2)O release from 1beta, 2beta(3)H-androstenedione, in testis and brain (200+/-23 and 25+/-6 pmol/min per mg, respectively) and below 3 pmol product formed/min per mg in other tissues. This study indicates that the testis, among the tissues analyzed, is the major source of aromatase in the adult stallion, and that the aromatase gene expression is specifically enhanced at this level, and is responsible for the high estrogen synthesis observed. Moreover, the study of aromatase in one colt testis has shown lower levels of transcripts, protein and enzyme activity, evidencing that aromatase is regulated during the development and may serve as a useful marker of testicular function. As the second organ where aromatase mRNA and activity are both well detected is brain, this study also underlines the possible role of neurosteroids in stallion on behaviour, brain function or central endocrine control.

  9. Exon-specific northern analysis and rapid amplification of cDNA ends (RACE) reveal that the proximal promoter II (PII) is responsible for aromatase cytochrome P450 (CYP19) expression in human ovary.

    PubMed

    Jenkins, C; Michael, D; Mahendroo, M; Simpson, E

    1993-11-01

    Estrogens are synthesized from C19 steroids by a unique form of cytochrome P450, aromatase cytochrome P-450 (P-450AROM; the product of the CYP19 gene). We have shown that tissue-specific expression of human P-450AROM is determined, in part, by the use of alternative promoters. Previous methods of analysis for determining the specific 5'-termini of the different transcripts included S1 nuclease protection, primer extension, and Northern analysis. In the present study we have used the RACE procedure (rapid amplification of cDNA ends) to amplify and clone the 5' termini of P-450AROM transcripts expressed in human corpus luteum (CL). Sequencing of the resulting clones supports the results of the previously performed studies. Specifically, the proximal promoter, PII, is the predominant promoter utilized in CL, such that the start of transcription occurs 26 bp downstream of the putative TATA sequence. A minority of the clones possess an alternative 5'-end, namely I.3. Exon-specific Northern analysis confirms that the majority of the P-450AROM transcripts in CL tissue contain sequence specific for promoter II. Similarly, exon-specific Northern analysis indicates that transcripts in human follicles, as well as granulosa cells in culture, contain primarily sequence specific for promoter II.

  10. Aromatase Activity and Bone Loss in Men

    PubMed Central

    Merlotti, Daniela; Gennari, Luigi; Stolakis, Konstantinos; Nuti, Ranuccio

    2011-01-01

    Aromatase is a specific component of the cytochrome P450 enzyme system responsible for the transformation of androgen precursors into estrogens. This enzyme is encoded by the CYP19A1 gene located at chromosome 15q21.2, that is, expressed in ovary and testis, but also in many extraglandular sites such as the placenta, brain, adipose tissue, and bone. The activity of aromatase regulates the concentrations of estrogens with endocrine, paracrine, and autocrine effects on target issues including bone. Importantly, extraglandular aromatization of circulating androgen precursors is the major source of estrogen in men. Clinical and experimental evidences clearly indicate that aromatase activity and estrogen production are necessary for longitudinal bone growth, the attainment of peak bone mass, pubertal growth spurt, epiphyseal closure, and normal bone remodeling in young individuals. Moreover, with aging, individual differences in aromatase activity may significantly affect bone loss and fracture risk in men. PMID:21772971

  11. Modelling inhibition of avian aromatase by azole pesticides

    PubMed Central

    Saxena, A.K.; Devillers, J.; Bhunia, S.S.; Bro, E.

    2015-01-01

    The potential effects of pesticides and their metabolites on the endocrine system are of major concern to wildlife and human health. In this context, the azole pesticides have earned special attention due to their cytochrome P450 aromatase inhibition potential. Cytochrome P450 aromatase (CYP19) catalyses the conversion of androstenedione and testosterone into oestrone and oestradiol, respectively. Thus, aromatase modulates the oestrogenic balance essential not only for females, but also for male physiology, including gonadal function. Its inhibition affects reproductive organs, fertility and sexual behaviour in humans and wildlife species. Several studies have shown that azole pesticides are able to inhibit human and fish aromatases but the information on birds is lacking. Consequently, it appeared to be of interest to estimate the aromatase inhibition of azoles in three different avian species, namely Gallus gallus, Coturnix coturnix japonica and Taeniopygia guttata. In the absence of the crystal structure of the aromatase enzyme in these bird species, homology models for the individual avian species were constructed using the crystal structure of human aromatase (hAr) (pdb: 3EQM) that showed high sequence similarity for G. gallus (82.0%), T. guttata (81.9%) and C. japonica (81.2%). A homology model with Oncorhynchus mykiss (81.9%) was also designed for comparison purpose. The homology-modelled aromatase for each avian and fish species and crystal structure of human aromatase were selected for docking 46 structurally diverse azoles and related compounds. We showed that the docking behaviour of the chemicals on the different aromatases was broadly the same. We also demonstrated that there was an acceptable level of correlation between the binding score values and the available aromatase inhibition data. This means that the homology models derived on bird and fish species can be used to approximate the potential inhibitory effects of azoles on their aromatase. PMID

  12. Synthesis and biochemical studies of 7 alpha-substituted androsta-1,4-diene-3,17-diones as enzyme-activated irreversible inhibitors of aromatase.

    PubMed

    Ebrahimian, S; Chen, H H; Brueggemeier, R W

    1993-09-01

    Several 7 alpha-thiosubstituted derivatives of androstenedione have demonstrated effective inhibition of aromatase, the cytochrome P450 enzyme complex responsible for the biosynthesis of estrogens. Introduction of an additional double bond in the A ring resulted in 7 alpha-(4'-amino)phenylthioandrosta-1,4-diene-3,17-dione (7 alpha-APTADD), a potent inhibitor that inactivated aromatase by an enzyme-catalyzed process. Additional 7 alpha-thiosubstituted androsta-1,4-diene-3,17-dione derivatives were designed to further examine enzyme-catalyzed inactivation. Two halogenated and one unsubstituted 7 alpha-phenylthioandrosta-1,4-diene-3,17-diones were synthesized via an acid-catalyzed conjugate Michael addition of substituted thiophenols with androsta-1,4,6-triene-3,17-dione. Two 7 alpha-naphthylthioandrosta-1,4-diene-3,17-diones were synthesized via either acid-catalyzed or based-catalyzed conjugate Michael addition of substituted thionaphthols with androsta-1,4,6-triene-3,17-dione. These agents were evaluated for aromatase inhibitory activity in the human placental microsomal preparation. Under initial velocity assay conditions of low product formation, the inhibitors demonstrated potent inhibition of aromatase, with apparent Ki's ranging from 12 to 27 nM. Furthermore, these compounds produced time-dependent, first-order inactivation of aromatase in the presence of NADPH, whereas no aromatase inactivation was observed in the absence of NADPH. This enzyme-activated irreversible inhibition, also referred to as mechanism-based inhibition, can be prevented by the substrate androstenedione. Thus, the apparent Ki values for these inhibitors are consistent with earlier studies on 7 alpha-substituted competitive inhibitors that indicate bulky substituents can be accommodated at the 7 alpha-position.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. The effects of insulin and follicle-simulating hormone (FSH) during in vitro development of ovarian goat preantral follicles and the relative mRNA expression for insulin and FSH receptors and cytochrome P450 aromatase in cultured follicles.

    PubMed

    Chaves, Roberta N; Duarte, Ana Beatriz G; Rodrigues, Giovanna Q; Celestino, Juliana J H; Silva, Gerlane M; Lopes, Claudio Afonso P; Almeida, Anderson P; Donato, Mariana A M; Peixoto, C A; Moura, Arlindo A A; Lobo, Carlos H; Locatelli, Yann; Mermillod, Pascalle; Campello, Claudio C; Figueiredo, Jose Ricardo

    2012-09-01

    The actions of different concentrations of insulin alone or in combination with follicle-stimulating hormone (FSH) were evaluated by in vitro follicular development and mRNA expression of cytochrome P450 aromatase (CYP19A1) and as receptors for insulin (INSR) and FSH (FSHR) from isolated, cultured goat preantral follicles. Goat preantral follicles were microdissected and cultured for 18 days in the absence or presence of insulin (5 and 10 ng/ml or 10 μg/ml) alone or in combination with FSH. After 18 days, the addition of the maximum concentration of insulin to the culture medium reduced follicular survival and antrum formation rates significantly compared to the other treatments. However, when FSH was added to the culture medium, no differences between these two parameters were observed. Preantral and antral follicles from the fresh control as well as from all cultured follicles still presented a normal ultrastructural pattern. In medium supplemented with FSH, only insulin at 10 ng/ml presented oocytes with higher rates of meiosis resumption compared to control, as well as oocytes in metaphase II. Treatment with insulin (10 ng/ml) plus FSH resulted in significantly increased levels of INSR and CYP19A1 mRNA compared to that with other treatments. In conclusion, 10 ng/ml insulin associated with FSH was more efficient in promoting resumption of oocyte meiosis, maintaining survival, stimulating follicular development, and increasing expression of the INSR and CYP19A1 genes in goat preantral follicles.

  14. Aromatase inhibitors: past, present and future.

    PubMed

    Séralini, G; Moslemi, S

    2001-06-10

    For the cellular physiology of sex steroid sensitive cells, the androgen/estrogen ratio may be more important than only one hormone action per se, in both sexes. This ratio is controlled in vertebrates by aromatase; its gene expression can be inhibited in different ways, and this is crucial for the treatment of estrogen-dependent diseases such as breast cancer, or gynecomastia in males for instance. To reach this goal, new steroidal and non-steroidal inhibitors are continuously being developed, and some of them are used as first or second line agents. Aromatase inhibition is also an essential tool for studying the role of estrogens in the adult, or during development. Aromatase inhibitors have shown in particular that estrogens are essential also in males for skeletal maturation and bone mineralization, development of masculine dendritic morphology in male brain linked to mating behaviour, and testicular function. Testosterone is often the prohormone converted in situ in active estrogens, at these levels. Several strategies can be used for aromatase inhibition. The first ones employed were blind screening or deductions from in vivo observations, which led for instance to the discovery of the role of aminoglutethimide in aromatase inhibition. Subsequently, in the years 1975-1990, the molecular modeling of compounds to mimic the substrate shape of the enzyme constituted the major idea. Hundreds of chemicals were synthesized by numerous authors, ranging from the well-known and very efficient 4-OHA to complicated imidazole or indane derivatives tested by sophisticated comparative molecular field analyses. Reticulum-bound active aromatase has not as yet been X-ray analyzed. Thus, aromatase inhibitors were also used more recently to probe and understand the active site conformation of the enzyme and its modelization was obtained from comparisons with bacterial-related cytochromes. We developed a mammalian model considerably closer to human aromatase in order to study the

  15. Phytochemicals for breast cancer prevention by targeting aromatase.

    PubMed

    Adams, Lynn S; Chen, Shiuan

    2009-01-01

    Aromatase is a cytochrome P450 enzyme (CYP19) and is the rate limiting enzyme in the conversion of androgens to estrogens. Suppression of in situ estrogen production through aromatase inhibition is the current treatment strategy for hormone-responsive breast cancers. Drugs that inhibit aromatase have been developed and are currently utilized as adjuvant therapy for breast cancer in post-menopausal women with hormone dependent breast cancer. Natural compounds have been studied extensively for important biologic effects such as antioxidant, anti-tumor and anti-viral effects. A significant number of studies have also investigated the aromatase inhibitory properties of a variety of plant extracts and phytochemicals. The identification of natural compounds that inhibit aromatase could be useful both from a chemopreventive standpoint and in the development of new aromatase inhibitory drugs. This review will discuss whole food extracts and the common classes of phytochemicals which have been investigated for potential aromatase inhibitory activity. We will review reported aromatase inhibition, kinetic data and possible structural variations that may inhibit or enhance the interaction of phytochemicals with the aromatase enzyme.

  16. Developmental regulation of aromatase activity in the rat hypothalamus

    SciTech Connect

    Lephart, E.D.

    1989-01-01

    The brain of all mammalian species studied thus far contain an enzymatic activity (aromatase) that catalyzes the conversion of androgens to estrogens. The activity is highest during prenatal development and contributes to the establishment of sex differences which determine adult gonadotropin secretion patterns and reproductive behavior. The studies presented in this dissertation represent a systematic effort to elucidate the mechanism(s) that control the initiation of and contribute to maintaining rat hypothalamic aromatase activity during pre- and postnatal development. Aromatase enzyme activity was measured by the {sup 3}H{sub 2}O release assay or by traditional estrogen product isolation. Brain aromatase mRNA was detected by hybridization to a cDNA encoding rat aromatase cytochrome P-450. In both males and females the time of puberty was associated with a decline in hypothalamic aromatase activity. This decline may represent a factor underlying the peri-pubertal decrease in the sensitivity to gonadal steroid feedback that accompanies completion of puberty. The results also indicate that androgens regulate brain aromatase levels during both the prepubertal and peri-pubertal stages of sexual development and that this regulation is transiently lost in young adults. Utilizing a hypothalamic organotypic culture system, aromatase activity in vitro was maintained for as long as two days. The results of studies of a variety of hormonal and metabolic regulators suggest that prenatal aromatase activity is regulated by factor(s) that function independently from the classical cyclic AMP and protein kinase C trans-membrane signaling pathways.

  17. Recent developments in steroidal and nonsteroidal aromatase inhibitors for the chemoprevention of estrogen-dependent breast cancer.

    PubMed

    Ahmad, Irshad; Shagufta

    2015-09-18

    Aromatase, a cytochrome P450 enzyme complex present in breast tissues, plays a significant role in the biosynthesis of important endogenous estrogens from androgens. The source of estrogen production in breast cancer tissues is intra-tumoral aromatase, and inhibition of aromatase may inhibit the growth stimulation effect of estrogens in breast cancer tissues. Consequently, aromatase is considered a useful therapeutic target in the treatment and prevention of estrogen-dependent breast cancer. Recently, different natural products and synthetic compounds have been rapidly developed, studied, and evaluated for aromatase inhibitory activity. Aromatase inhibitors are classified into two categories on the basis of their chemical structures, i.e., steroidal and nonsteroidal aromatase inhibitors. This review highlights the synthetic steroidal and nonsteroidal aromatase inhibitors reported in the literature in the last few years and will aid medicinal chemists in the design and synthesis of novel and pharmacologically-potent aromatase inhibitors for the treatment of breast cancer.

  18. Effects of flavonoids on aromatase activity, an in vitro study.

    PubMed

    Pelissero, C; Lenczowski, M J; Chinzi, D; Davail-Cuisset, B; Sumpter, J P; Fostier, A

    1996-02-01

    In the study, the inhibitory effect of flavonoids, including isoflavonic phytoestrogens, on the ovarian aromatase enzyme complex from the rainbow trout, Oncorhynchus mykiss, was assessed in vitro. Some of the compounds tested on fish were also tested on human placental aromatase activity as a comparison between the two sources of enzyme. It was found that flavone, dl-aminoglutethimide, apigenin, quercetin, 7,4'- dihydroxyflavone, alpha-naphthoflavone and equol were potent inhibitors of the ovarian aromatase activity in rainbow trout. Relative potencies (RP) of these compounds compared to flavone (assigned an effect of 1) were, respectively, 19.0, 8.7, 5.3, 3.7, 3.2 and 0.9. Two other phytoestrogens, namely biochanin A and genistein, slightly inhibited aromatase activity. Finally, 7-hydroxyflavone, formononetin, daidzein, coumestrol, chrysin, flavanone and estradiol-17beta did not inhibit ovarian aromatase activity at doses up to 1000 microM. Experiments on human placental aromatase showed inhibitory effects of dl-aminoglutethimide, flavone, flavanone and equol with RP values of 2.8. 1, 1.5 and 0.4, respectively. These results are in accordance with previous studies. The influence of the experimental procedure on IC50 values and RP is discussed.

  19. Molecular basis for the interaction of four different classes of substrates and inhibitors with human aromatase.

    PubMed

    Hong, Yanyan; Cho, Michael; Yuan, Yate-Ching; Chen, Shiuan

    2008-03-01

    Aromatase cytochrome P450 (CYP19) converts androgen to estrogen. In this study, the interactions of four classes of compounds, 17beta-estradiol (the product of aromatase), 17-methyltestosterone (a synthetic androgen), dibenzylfluorescein (a synthetic substrate of aromatase), and coumestrol (a phytoestrogen), with aromatase were investigated through spectral analysis using purified human recombinant aromatase and site-directed mutagenesis studies using CHO cells expressing wild-type human aromatase or five aromatase mutants, E302D, D309A, T310S, S478T and H480Q. Spectral analysis showed that a type I binding spectrum was produced by the binding of 17-methyltestosterone to aromatase and a novel binding spectrum of aromatase was induced by dibenzylfluorescein. Mutagenesis experiments demonstrated that residues S478 and H480 in the beta-4 sheet play an important role in the binding of all four compounds. Computer-assisted docking of these compounds into the three-dimensional model of aromatase revealed that: (1) weak interaction between 17beta-estradiol and the beta-4 sheet of aromatase facilitates the release of 17beta-estradiol from the active site of aromatase; (2) 17-methyl group of 17-methyltestosterone affects its binding to aromatase; (3) dibenzylfluorescein binds to the active site of aromatase with its O-dealkylation site near the heme iron and residue T310; and (4) coumestrol binds to aromatase in a manner such that rings A and C of coumestrol mimic rings A and B of steroid. These structure-function studies help us to evaluate the structural model of aromatase, and to accelerate the structure-based design for new aromatase inhibitors.

  20. Design and Synthesis of Norendoxifen Analogues with Dual Aromatase Inhibitory and Estrogen Receptor Modulatory Activities

    PubMed Central

    Lv, Wei; Liu, Jinzhong; Skaar, Todd C.; Flockhart, David A.; Cushman, Mark

    2015-01-01

    Both selective estrogen receptor modulators and aromatase inhibitors are widely used for the treatment of breast cancer. Compounds with both aromatase inhibitory and estrogen receptor modulatory activities could have special advantages for treatment of breast cancer. Our previous efforts led to the discovery of norendoxifen as the first compound with dual aromatase inhibitory and estrogen receptor binding activities. To optimize its efficacy and aromatase selectivity versus other cytochrome P450 enzymes, a series of structurally related norendoxifen analogues were designed and synthesized. The most potent compound, 4'-hydroxynorendoxifen (10), displayed elevated inhibitory potency against aromatase and enhanced affinity for estrogen receptors when compared to norendoxifen. The selectivity of 10 for aromatase versus other cytochrome P450 enzymes was also superior to norendoxifen. 4'-Hydroxynorendoxifen is therefore an interesting lead for further development to obtain new anticancer agents of potential value for the treatment of breast cancer. PMID:25751283

  1. Effect of low dose exposure to the herbicide atrazine and its metabolite on cytochrome P450 aromatase and steroidogenic factor-1 mRNA levels in the brain of premetamorphic bullfrog tadpoles (Rana catesbeiana)

    PubMed Central

    Gunderson, Mark P.; Veldhoen, Nik; Skirrow, Rachel C.; Macnab, Magnus K.; Ding, Wei; van Aggelen, Graham; Helbing, Caren C.

    2011-01-01

    The transcriptional regulator steroidogenic factor 1 (SF-1) and the enzyme cytochrome P450 aromatase (CYP19) play a central role in modulation of a broad range of tissue-specific developmental processes associated with hormone homeostasis that includes differentiation of the central nervous system. SF-1 and CYP19 expression may be targeted by a variety of endocrine disruptive agents prevalent within the environment. In the present study, we cloned and characterized partial sequences for bullfrog (Rana catesbeiana) SF-1 and CYP19 and examined the effects of a 48 h exposure to 1 and 100 μg/L of the herbicide atrazine (ATZ) and its major metabolite desethylatrazine (DEA), as well as 5 ng/L of the estrogenic chemical, 17α-ethynylestradiol (EE2), and 673 ng/L of the thyroid hormone, 3,5, 3′-triiodothyronine (T3), on SF-1 and CYP19 mRNA abundance in the brains of premetamorphic bullfrog tadpoles. Quantitative RT-PCR analysis showed an increase in CYP19 mRNA following a 48 h exposure to EE2 but not T3 while no significant changes in SF-1 transcript levels occurred. We observed a strong positive correlation between CYP19 and SF-1 transcript abundance in the ATZ-exposed animals which was not evident with DEA- or hormone-exposed tadpoles. Our results are intriguing in light of reported behavioral changes in ATZ-exposed frogs and suggest that further research is warranted to examine the relationship and role of CYP19 and SF-1 in amphibian brain development. PMID:21371610

  2. A yeast screen system for aromatase inhibitors and ligands for androgen receptor: yeast cells transformed with aromatase and androgen receptor.

    PubMed

    Mak, P; Cruz, F D; Chen, S

    1999-11-01

    Endocrine disruptors are hormone mimics that modify hormonal action in humans and animals. It is thought that some endocrine disruptors modify estrogen and androgen action in humans and animals by suppressing aromatase activity. Aromatase cytochrome P450 is the key enzyme that converts C19 androgens to aromatic C18 estrogenic steroids. We have developed a novel aromatase inhibitor screening method that allows us to identify antiaromatase activity of various environmental chemicals. The screen was developed by coexpressing the human aromatase and the mouse androgen receptor in yeast cells, which carry the androgen-responsive ss-galactosidase reporter plasmid. Functional expression of aromatase in yeast has been demonstrated using the [3H]-water release assay with intact cells as well as with yeast microsomes. The aromatase activity could be blocked by known aromatase inhibitors such as aminoglutethimide (AG). Yeast-produced androgen receptors were able to transactivate a yeast basal promoter linked to an androgen-responsive element in response to androgens. The resultant triple yeast transformant responded to the treatment of testosterone, androstenedione, or 5 alpha-dihydrotestosterone (5 alpha-DHT). In the absence of the aromatase inhibitor AG, transcriptional activation was observed only for the nonaromatizable androgen 5 alpha-DHT. However, the two aromatizable androgens (testosterone and androstenedione) induced the reporter activity in the presence of AG. Using this yeast-based assay, we confirmed that two flavones, chrysin and alpha-naphtholflavone, are inhibitors of aromatase. Thus, this yeast system allows us to develop a high-throughput screening method, without using radioactive substrate, to identify aromatase inhibitors as well as new ligands (nonaromatizable androgen mimics) for the androgen receptors. In addition, this screening method also allows us to distinguish nonandrogenic aromatase inhibitors from inhibitors with androgenic activity. This yeast

  3. Mechanism-based Categorization of Aromatase Inhibitors: A Potential Discovery and Screening Tool

    EPA Science Inventory

    Cytochrome P450 aromatase is a key steroidogenic enzyme that converts androgens to estrogens in vertebrates. There is much interest in aromatase inhibitors (AIs) because a number of environmental contaminants can act as AIs, thereby disrupting endocrine function in humans and wil...

  4. Integrated approach to explore the mechanisms of aromatase inhibition and recovery in fathead minnows (Pimephales promelas)

    EPA Science Inventory

    Aromatase, a member of the cytochrome P450 superfamily, is a key enzyme in estradiol synthesis that catalyzes the aromatization of androgens into estrogens in ovaries. Here, we used an integrated approach to assess the mechanistic basis of the direct effects of aromatase inhibiti...

  5. Tissue-specific expression of the human aromatase cytochrome P-450 gene by alternative use of multiple exons 1 and promoters, and switching of tissue-specific exons 1 in carcinogenesis.

    PubMed Central

    Harada, N; Utsumi, T; Takagi, Y

    1993-01-01

    Extensive screening of aromatase cDNA was carried out in cDNA libraries from various human tissues. The DNA sequences of all the isolated cDNA clones were identical in the region encoded by exons 2-10 of the aromatase gene. However, tissue-specific sequences, which were classified into four groups, were observed in the 5' portions of the clones corresponding to the region encoded by exon 1. All of them were also found in clones isolated from a human genomic library and mapped between exons 1 and 2 of the human aromatase gene reported previously, suggesting the presence of multiple exons 1 and promoters in the gene. Reverse transcription-PCR analyses of aromatase mRNAs in various tissues revealed that aromatase transcripts are tissue-specifically spliced by alternative use of multiple exons 1, although minor forms of the transcripts were also present in each tissue. Aromatase mRNA is spliced from 10 exons in most tissues, but from 9 exons in the prostate and from 10 or 11 exons in the placenta. This suggests that tissue-specific regulation of the aromatase gene in various tissues may be explained by alternative use of multiple exons 1 flanked with tissue-specific promoters. The alternative use of multiple exons 1 for liver transcripts was found to change developmentally. Furthermore, switch from an adipose-specific exon 1 to another type of exon 1 was observed in aromatase transcripts of adipose tissues of three of five breast cancer patients. Images Fig. 3 Fig. 4 PMID:8248245

  6. The effects of dietary phytoestrogens on aromatase activity in human endometrial stromal cells.

    PubMed

    Edmunds, Katie M; Holloway, Alison C; Crankshaw, Denis J; Agarwal, Sanjay K; Foster, Warren G

    2005-01-01

    Dietary phytoestrogens have been reported to inhibit aromatase activity in placental microsomes, but the effects in the human endometrium are unknown. Aromatase, the rate-limiting enzyme in the conversion of androgens to estrogens, has recently been shown to be expressed in the endometrium of women with endometriosis and is thought to play a role in the pathophysiology of this disease. Therefore, the objective of this study was to screen dietary phytoestrogens for their ability to inhibit aromatase activity in human endometrial stromal cells (ESC) and identify potential novel therapeutic agents for the treatment of endometriosis. The inhibition of aromatase activity by direct interaction with the dietary phytoestrogens genistein, daidzein, chrysin, and naringenin was tested in a cell free assay. Furthermore, test compound effects on aromatase activity in ESC cultures were also examined. Genistein and daidzein were inactive in the human recombinant aromatase assay whereas naringenin and chrysin inhibited aromatase activity. However, genistein (1 nM to 1 mM) stimulated aromatase activity in ESC whereas other phytoestrogens had no effect. Immunopositive aromatase cells were demonstrated in genistein-treated ESC but not in untreated control cultures. Taken together, our data suggest that genistein can increase aromatase activity in ESC likely via increased enzyme expression.

  7. White button mushroom phytochemicals inhibit aromatase activity and breast cancer cell proliferation.

    PubMed

    Grube, B J; Eng, E T; Kao, Y C; Kwon, A; Chen, S

    2001-12-01

    Estrogen is a major factor in the development of breast cancer. In situ estrogen production by aromatase/estrogen synthetase in breast cancer plays a dominant role in tumor proliferation. Because natural compounds such as flavones and isoflavones have been shown to be inhibitors of aromatase, it is thought that vegetables that contain these phytochemicals can inhibit aromatase activity and suppress breast cancer cell proliferation. Heat-stable extracts were prepared from vegetables and screened for their ability to inhibit aromatase activity in a human placental microsome assay. The white button mushroom (species Agaricus bisporus) suppressed aromatase activity dose dependently. Enzyme kinetics demonstrated mixed inhibition, suggesting the presence of multiple inhibitors or more than one inhibitory mechanism. "In cell" aromatase activity and cell proliferation were measured using MCF-7aro, an aromatase-transfected breast cancer cell line. Phytochemicals in the mushroom aqueous extract inhibited aromatase activity and proliferation of MCF-7aro cells. These results suggest that diets high in mushrooms may modulate the aromatase activity and function in chemoprevention in postmenopausal women by reducing the in situ production of estrogen.

  8. Three-dimensional quantitative structure-activity relationships of steroid aromatase inhibitors

    NASA Astrophysics Data System (ADS)

    Oprea, Tudor I.; García, Angel E.

    1996-06-01

    Inhibition of aromatase, a cytochrome P450 that converts androgens to estrogens, is relevant in the therapeutic control of breast cancer. We investigate this inhibition using a three-dimensional quantitative structure-activity relationship (3D QSAR) method known as Comparative Molecular Field Analysis, CoMFA [Cramer III, R.D. et al., J. Am. Chem. Soc., 110 (1988) 5959]. We analyzed the data for 50 steroid inhibitors [Numazawa, M. et al., J. Med. Chem., 37 (1994) 2198, and references cited therein] assayed against androstenedione on human placental microsomes. An initial CoMFA resulted in a three-component model for log(1/Ki), with an explained variance r2 of 0.885, and a cross-validated q2 of 0.673. Chemometric studies were performed using GOLPE [Baroni, M. et al., Quant. Struct.-Act. Relatsh., 12 (1993) 9]. The CoMFA/GOLPE model is discussed in terms of robustness, predictivity, explanatory power and simplicity. After randomized exclusion of 25 or 10 compounds (repeated 25 times), the q2 for one component was 0.62 and 0.61, respectively, while r2 was 0.674. We demonstrate that the predictive r2 based on the mean activity (Ym) of the training set is misleading, while the test set Ym-based predictive r2 index gives a more accurate estimate of external predictivity. Using CoMFA, the observed differences in aromatase inhibition among C6-substituted steroids are rationalized at the atomic level. The CoMFA fields are consistent with known, potent inhibitors of aromatase, not included in the model. When positioned in the same alignment, these compounds have distinct features that overlap with the steric and electrostatic fields obtained in the CoMFA model. The presence of two hydrophobic binding pockets near the aromatase active site is discussed: a steric bulk tolerant one, common for C4, C6-alpha and C7-alpha substitutents, and a smaller one at the C6-beta region.

  9. Combining computational and biochemical studies for a rationale on the anti-aromatase activity of natural polyphenols.

    PubMed

    Neves, Marco A C; Dinis, Teresa C P; Colombo, Giorgio; Sá e Melo, M Luisa

    2007-12-01

    Aromatase, an enzyme of the cytochrome P450 family, is a very important pharmacological target, particularly for the treatment of breast cancer. The anti-aromatase activity of a set of natural polyphenolic compounds was evaluated in vitro. Strong aromatase inhibitors including flavones, flavanones, resveratrol, and oleuropein, with activities comparable to that of the reference anti-aromatase drug aminoglutethimide, were identified. Through the application of molecular modeling techniques based on grid-independent descriptors and molecular interaction fields, the major physicochemical features associated with inhibitory activity were disclosed, and a putative virtual active site of aromatase was proposed. Docking of the inhibitors into a 3D homology model structure of the enzyme defined a common binding mode for the small molecules under investigation. The good correlation between computational and biological results provides the first rationalization of the anti-aromatase activity of polyphenolic compounds. Moreover, the information generated in this approach should be further exploited for the design of new aromatase inhibitors.

  10. Inhibition and inactivation of equine aromatase by steroidal and non-steroidal compounds. A comparison with human aromatase inhibition.

    PubMed

    Moslemi, S; Seralini, G E

    1997-12-01

    In order to approach the detailed structure-function relationships of aromatase, we studied the inhibitory and inactivatory potencies of several steroidal androstenedione analogues (1: 4-hydroxyandrostenedione, 2: 4-acetoxyandrostenedione and 3: 7 alpha-(4'-amino)phenylthio-4-androstene-3, 17-dione) and non-steroidal imidazole derivatives (4: ketoconazole, 5: miconazole and 6: fadrozole) on equine aromatase in placental microsomes, a well established mammalian model. Human placental microsomes and the purified enzyme from equine testis were also used to compare inhibition by 1 and 2. In equine microsomes, all compounds tested exhibited a competitive inhibition, with Ki values of 4.1, 26 and 1.8 nM for 1, 2 and 3, and of 2400, 1.4 and 4 nM for 4, 5, and 6, respectively. The Km for androstenedione, the substrate mainly used in these studies, was 1.8 +/- 0.13 nM. The three non-steroidal derivatives did not inactivate equine aromatase, but 1 and 2 acted as comparable inactivators to a much higher degree than 3. Compound 1 inhibited in a similar manner (89-94%) purified or equine and human microsomal aromatases, whereas 2 inhibited microsomal aromatase more efficiently in the horse than in man (92% and 33% inhibition, respectively). There was only a 40% inhibition with 2 on the purified equine enzyme, which is no more in the natural membrane environment. The comparisons between equine and human microsomal aromatases allow precise functional and structural differences to be observed with these enzymes.

  11. Metformin Reverses Development of Pulmonary Hypertension via Aromatase Inhibition.

    PubMed

    Dean, Afshan; Nilsen, Margaret; Loughlin, Lynn; Salt, Ian P; MacLean, Margaret R

    2016-08-01

    Females are more susceptible to pulmonary arterial hypertension than males, although the reasons remain unclear. The hypoglycemic drug, metformin, is reported to have multiple actions, including the inhibition of aromatase and stimulation of AMP-activated protein kinase. Inhibition of aromatase using anastrazole is protective in experimental pulmonary hypertension but whether metformin attenuates pulmonary hypertension through this mechanism remains unknown. We investigated whether metformin affected aromatase activity and if it could reduce the development of pulmonary hypertension in the sugen 5416/hypoxic rat model. We also investigated its influence on proliferation in human pulmonary arterial smooth muscle cells. Metformin reversed right ventricular systolic pressure, right ventricular hypertrophy, and decreased pulmonary vascular remodeling in the rat. Furthermore, metformin increased rat lung AMP-activated protein kinase signaling, decreased lung and circulating estrogen levels, levels of aromatase, the estrogen metabolizing enzyme; cytochrome P450 1B1 and its transcription factor; the aryl hydrocarbon receptor. In human pulmonary arterial smooth muscle cells, metformin decreased proliferation and decreased estrogen synthesis by decreasing aromatase activity through the PII promoter site of Cyp19a1 Thus, we report for the first time that metformin can reverse pulmonary hypertension through inhibition of aromatase and estrogen synthesis in a manner likely to be mediated by AMP-activated protein kinase.

  12. Molecular mechanisms of aromatase inhibition by new A, D-ring modified steroids.

    PubMed

    Cepa, Margarida; Correia-da-Silva, Georgina; Tavares da Silva, Elisiário J; Roleira, Fernanda M F; Hong, Yanyan; Chen, Shiuan; Teixeira, Natércia A

    2008-09-01

    A recent approach for treatment and prevention of estrogen-dependent breast cancer focuses on the inhibition of aromatase, the enzyme that catalyzes the final step of estrogen biosynthesis. Some synthetic steroids, such as formestane and exemestane, resembling the natural enzyme substrate androstenedione, revealed to be potent and useful aromatase inhibitors (AIs) and were approved for the treatment of estrogen-dependent breast cancer in postmenopausal women. Recently, we found that five newly synthesized steroids with chemical features in the A- and D-rings considered important for drug-receptor interaction efficiently inhibit aromatase derived from human placental microsomes. In this work, these steroids showed a similar pattern of anti-aromatase activity in several aromatase-expressing cell lines. 5alpha-androst-3-en-17-one and 3alpha,4alpha-epoxy-5alpha-androstan-17-one were revealed to be the most potent inhibitors. These compounds induced a time-dependent inhibition of aromatase, showing to be irreversible AIs. The specific interactions of these compounds with aromatase active sites were further demonstrated by site-directed mutagenesis studies and evaluated by computer-aided molecular modeling. Both compounds were able to suppress hormone-dependent proliferation of MCF-7aro cells in a dose-dependent manner. These findings are important for the elucidation of a structure-activity relationship on aromatase, which may help in the development of new AIs.

  13. Presence of aromatase inhibitors in cycads.

    PubMed

    Kowalska, M T; Itzhak, Y; Puett, D

    1995-07-28

    Cycads, the most primitive of the living gymnosperms, have been used and continue to be used for food and medicinal purposes by many cultures, although toxins must be removed before ingestion. In our quest to identify tropical plants that contain inhibitors of the cytochrome P-450 aromatase and thus may be efficacious in treating estrogen-dependent tumors, we have screened extracts from 5 species of cycad folia encompassing 3 genera: Cycas cairnsiana F. Muell., Cycas revoluta Thunb., Cycas rumphii Miq., Dioon spinulosum Dyer and Encephalartos ferox Bertol. All extracts were found to contain inhibitors of the human enzyme.

  14. Aromatase inhibitors: possible future applications.

    PubMed

    Karaer, Oznur; Oruç, Semra; Koyuncu, Faik Mümtaz

    2004-08-01

    In premenopausal women ovaries are the major sites of estrogen production, while in postmenopausal women estrogen is produced by aromatization of ovarian and adrenal androgens in extragonadal sites, mostly in adipose tissue. Aromatase is a cytochrome P450 hemoprotein-containing enzyme complex that catalyzes the rate-limiting step in the conversion of androstenedione and testosterone to estrone and estradiol (E2). Aromatase inhibitors (AIs) have been developed primarily for use in either natural or surgical postmenopausal patients. In premenopausal women, the ovary can overcome the estrogen blockade by reflex increments of luteinizing hormone (LH) and follicle stimulating hormone (FSH), so AIs must be combined with a gonadotropin releasing hormone (GnRH) agonist to prevent the reflex LH and FSH increments. In advanced hormone-dependent breast cancer treatment, AIs have been shown to be superior to tamoxifen. Preliminary evidence also suggests superiority in the adjuvant, neoadjuvant settings and also for breast cancer prevention. AIs have been used in infertility and can increase ovulation rate. Reducing FSH dose, estrogen levels, improving response to FSH, implantation rates, and developing multiple follicles that can be used in in vitro maturation procedures are potential areas that AIs might be used in in assisted reproductive technologies (ART), besides simple ovulation induction. AIs are reported to be successful in treatment of endometriosis, an estrogen-dependent process. The use of AIs in gynecomastia, puberte precox, leiomyoma uteri, some estrogen-dependent cancers (ovarian), endometrial cancer and male infertility are reported; some of the results are promising but more clinical trials are needed. AIs are predicted to become the gold standard in the treatment of estrogen-dependent diseases in reproductive medicine in the near future.

  15. Synthesis and aromatase inhibitory activity of novel pyridine-containing isoflavones.

    PubMed

    Kim, Young-Woo; Hackett, John C; Brueggemeier, Robert W

    2004-07-29

    Aromatase, a cytochrome P450 hemoprotein that is responsible for estrogen biosynthesis by conversion of androgens into estrogens, has been an attractive target in the treatment of hormone-dependent breast cancer. As a result, a number of synthetic steroidal or nonsteroidal aromatase inhibitors have been successfully developed. In addition, there are several classes of natural products that exert potent activities in aromatase inhibition, with the flavonoids being most prominent. Previous studies have exploited flavone and flavanone scaffolds for the development of new aromatase inhibitors. In this paper, we describe the design, synthesis, and biological evaluation of a novel series of 2-(4'-pyridylmethyl)thioisoflavones as the first example of synthetic isoflavone-based aromatase inhibitors.

  16. Placental hypoxia during placental malaria

    PubMed Central

    Boeuf, Philippe; Tan, Aimee; Romagosa, Cleofe; Radford, Jane; Mwapasa, Victor; Molyneux, Malcolm E.; Meshnick, Steven R.; Hunt, Nicholas H.; Rogerson, Stephen J.

    2009-01-01

    Background Placental malaria causes fetal growth retardation (FGR), which has been linked epidemiologically to placental monocyte infiltrates. We investigated whether parasite or monocyte infiltrates were associated with placental hypoxia, as a potential mechanism underlying malarial FGR. Methods We studied the hypoxia markers hypoxia inducible factor (HIF)-1α, vascular endothelial growth factor (VEGF), placental growth factor, VEGF receptor 1 and its soluble form and VEGF receptor 2. We used real time PCR (in 59 women) to examine gene transcription, immunohistochemistry (in 30 women) to describe protein expression and laser capture microdissection (in 23 women) to examine syncytiotrophoblast-specific changes in gene expression. We compared gene and protein expression in relation to malaria infection, monocytes infiltrates and birth weight. Results we could not associate any hallmark of placental malaria with a transcription, expression or tissue distribution profile characteristic of a response to hypoxia but found higher HIF-1α (P=.0005) and lower VEGF levels (P=.0026) in the syncytiotrophoblast of malaria cases versus asymptomatic controls. Conclusion our data are inconsistent with a role for placental hypoxia in the pathogenesis of malaria-associated FGR. The laser capture microdissection study was small, but suggests that malaria affects syncytiotrophoblast gene transcription, and proposes novel potential mechanisms for placental malaria-associated FGR. PMID:18279052

  17. A yeast screen system for aromatase inhibitors and ligands for androgen receptor: yeast cells transformed with aromatase and androgen receptor.

    PubMed Central

    Mak, P; Cruz, F D; Chen, S

    1999-01-01

    Endocrine disruptors are hormone mimics that modify hormonal action in humans and animals. It is thought that some endocrine disruptors modify estrogen and androgen action in humans and animals by suppressing aromatase activity. Aromatase cytochrome P450 is the key enzyme that converts C19 androgens to aromatic C18 estrogenic steroids. We have developed a novel aromatase inhibitor screening method that allows us to identify antiaromatase activity of various environmental chemicals. The screen was developed by coexpressing the human aromatase and the mouse androgen receptor in yeast cells, which carry the androgen-responsive ss-galactosidase reporter plasmid. Functional expression of aromatase in yeast has been demonstrated using the [3H]-water release assay with intact cells as well as with yeast microsomes. The aromatase activity could be blocked by known aromatase inhibitors such as aminoglutethimide (AG). Yeast-produced androgen receptors were able to transactivate a yeast basal promoter linked to an androgen-responsive element in response to androgens. The resultant triple yeast transformant responded to the treatment of testosterone, androstenedione, or 5 alpha-dihydrotestosterone (5 alpha-DHT). In the absence of the aromatase inhibitor AG, transcriptional activation was observed only for the nonaromatizable androgen 5 alpha-DHT. However, the two aromatizable androgens (testosterone and androstenedione) induced the reporter activity in the presence of AG. Using this yeast-based assay, we confirmed that two flavones, chrysin and alpha-naphtholflavone, are inhibitors of aromatase. Thus, this yeast system allows us to develop a high-throughput screening method, without using radioactive substrate, to identify aromatase inhibitors as well as new ligands (nonaromatizable androgen mimics) for the androgen receptors. In addition, this screening method also allows us to distinguish nonandrogenic aromatase inhibitors from inhibitors with androgenic activity. This yeast

  18. New aromatase inhibitors. Synthesis and biological activity of aryl-substituted pyrrolizine and indolizine derivatives.

    PubMed

    Sonnet, P; Dallemagne, P; Guillon, J; Enguehard, C; Stiebing, S; Tanguy, J; Bureau, R; Rault, S; Auvray, P; Moslemi, S; Sourdaine, P; Séralini, G E

    2000-05-01

    We report herein the design and the synthesis of some aryl-substituted pyrrolizine and indolizine derivatives, on the basis of a hypothetical pharmacophore structure designed to fit the catalytic site of the human cytochrome P450 aromatase. The in vitro biological evaluation of these compounds allowed us to point out two new potent non-steroidal aromatase inhibitors, MR 20494 and MR 20492, with IC50 values in the range of 0.1 microM.

  19. Aromatase, Aromatase Inhibitors, and Breast Cancer

    PubMed Central

    Chumsri, Saranya; Howes, Timothy; Bao, Ting; Sabnis, Gauri; Brodie, Angela

    2011-01-01

    Estrogens are known to be important in the growth of breast cancers in both pre- and postmenopausal women. As the number of breast cancer patients increases with age, the majority of breast cancer patients are postmenopausal women. Although estrogens are no longer made in the ovaries after menopause, peripheral tissues produce sufficient concentrations to stimulate tumor growth. As aromatase catalyzes the final and rate-limiting step in the biosynthesis of estrogen, inhibitors of this enzyme are effective targeted therapy for breast cancer. Three aromatase inhibitors (AIs) are now FDA approved and have been shown to be more effective than the antiestrogen tamoxifen and are well tolerated. AIs are now a standard treatment for postmenopausal patients. AIs are effective in adjuvant and first-line metastatic setting. This review describes the development of AIs and their current use in breast cancer. Recent research focuses on elucidating mechanisms of acquired resistance that may develop in some patients with long term AI treatment and also on innate resistance. Preclinical data in resistance models demonstrated that the crosstalk between ER and other signaling pathways particularly MAPK and PI3K/Akt is an important resistant mechanism. Blockade of these other signaling pathways is an attractive strategy to circumvent the resistance to AI therapy in breast cancer. Several clinical trials are ongoing to evaluate the role of these novel targeted therapies to reverse resistance to AIs. PMID:21335088

  20. Immunolocalization of aromatase in stallion Leydig cells and seminiferous tubules.

    PubMed

    Sipahutar, Herbert; Sourdaine, Pascal; Moslemi, Safa; Plainfossé, Bruno; Séralini, Gilles-Eric

    2003-03-01

    High levels of plasma estrogens constitute an endocrine peculiarity of the adult stallion. This is mostly due to testicular cytochrome p450 aromatase, the only irreversible enzyme responsible for the bioconversion of androgens into estrogens. To identify more precisely the testicular aromatase synthesis sites in the stallion, testes from nine horses (2-5 years) were obtained during winter or spring. Paraplast-embedded sections were processed using rabbit anti-equine aromatase, followed by biotinylated goat anti-rabbit antibodies, and amplified with a streptavidin-peroxidase complex. Immunoreactivity was detected with diaminobenzidine. Immunofluorescence detection, using fluoroisothiocyanate-conjugated goat anti-rabbit antibodies, was also applied. Specific aromatase immunoreactivity was observed intensely in Leydig cells but also for the first time, to a lesser extent, in the cytoplasm surrounding germ cells at the junction with Sertoli cells. Interestingly, the immunoreactivity in Sertoli cells appears to vary with the spermatogenic stages in the basal compartment (with spermatogonia) as well as in the adluminal one (with spermatids). Relative staining intensity in Leydig and Sertoli cells and testicular microsomal aromatase activity increased with age. The present study in stallions indicates that in addition to Leydig cells, Sertoli cells also appear to participate in estrogen synthesis, and this could play a paracrine role in the regulation of spermatogenesis.

  1. Molecular pharmacology of aromatase and its regulation by endogenous and exogenous agents.

    PubMed

    Brueggemeier, R W; Richards, J A; Joomprabutra, S; Bhat, A S; Whetstone, J L

    2001-12-01

    Aromatase (estrogen synthase) is the cytochrome P450 enzyme complex that converts C19 androgens to C18 estrogens. Aromatase activity has been demonstrated in breast tissue in vitro, and expression of aromatase is highest in or near breast tumor sites. Thus, local regulation of aromatase by both endogenous factors as well as exogenous medicinal agents will influence the levels of estrogen available for breast cancer growth. The prostaglandin E2 (PGE2) increases intracellular cAMP levels and stimulates estrogen biosynthesis, and our recent studies have shown a strong linear association between CYP19 expression and the sum of COX-1 and COX-2 expression in breast cancer specimens. PGE2 can bind to four receptor subtypes, EP1-EP4, which are coupled to different intracellular signaling pathways. In primary human breast stromal cell cultures, aromatase activity was significantly induced by PGE2, dexamethasone, and agonists for the EP1 and EP2 receptor subtypes. An EP1 antagonist, SC-19220, inhibited the induction of enzyme activity by PGE2 or 17-phenyltrinor-PGE2, an EP1 agonist. Sulprostone, an EP3 agonist, did not alter aromatase activity levels. Investigations are also underway on the regulation of aromatase by exogenous medicinal agents. Selective steroidal and nonsteroidal agents are effective in inhibiting breast tissue aromatase. The benzopyranone ring system is a molecular scaffold of considerable interest, and this scaffold is found in certain flavonoid natural products that have weak aromatase inhibitory activity. Our novel synthetic route for benzopyranones utilizes readily available salicylic acids and terminal alkynes as starting materials. The synthesis of flavones with diversity on the benzopyranone moiety and at the C-2 position occurs with good to excellent yields using these reaction conditions, resulting in an initial benzopyranone library of thirty compounds exhibiting enhanced and differential aromatase inhibition. Current medicinal chemistry efforts

  2. Effects of a short-term exposure to the aromatase inhibitor fadrozole on steroid production and gene expression in the ovary of female fathead minnows (Pimephales promelas)

    EPA Science Inventory

    Cytochrome P450 aromatase is a steriodogenic enzyme that converts C19 androgens to C18 estrogens and is critical for normal reproduction in females. Fadrozole is a well-studied aromatase inhibitor that has been shown to suppress estrogen production in the ovaries of fish. Howev...

  3. Placental insufficiency

    MedlinePlus

    ... other drugs Certain medicines can also increase the risk of placental insufficiency. In some cases, the placenta: May have an abnormal shape May not grow big enough (more likely if you are carrying twins or other multiples) Does not attach correctly to ...

  4. Tamoxifen metabolites as active inhibitors of aromatase in the treatment of breast cancer.

    PubMed

    Lu, Wenjie Jessie; Desta, Zeruesenay; Flockhart, David A

    2012-01-01

    The mechanism of tamoxifen action in the treatment of breast cancer is believed to be via active metabolites that act as potent estrogen receptor antagonists. Attempts to identify relationships between active metabolite concentrations and clinical outcomes have produced mixed results. Since anti-estrogenic effects may be brought about not only by estrogen antagonism, but also by reduced estrogen synthesis, we tested the ability of tamoxifen and its principal metabolites to inhibit aromatase in vitro. The activity of human aromatase in both recombinant and placental microsomal preparations was measured using the rate of generation of a fluorescent metabolite in the presence and absence of multiple concentrations of tamoxifen, endoxifen, N-desmethyl-tamoxifen, and Z-4-hydroxy-tamoxifen. Aromatase inhibition was further characterized by measuring the inhibition of testosterone metabolism to estradiol. The biochemical mechanisms of inhibition were documented and their inhibitory potency was compared. Using recombinant human aromatase, endoxifen, and N-desmethyl-tamoxifen were able to inhibit aromatase activity with K (i) values of 4.0 and 15.9 μM, respectively. Detailed characterization of inhibition by endoxifen and N-desmethyl-tamoxifen indicated non-competitive kinetics for both inhibitors. Similarly, endoxifen-inhibited testosterone metabolism via a non-competitive mechanism. No appreciable inhibition by tamoxifen or Z-4-hydroxy-tamoxifen was observed at similar concentrations. The relative inhibitory potency was: endoxifen > N-desmethyl-tamoxifen > Z-4-hydroxy-tamoxifen > tamoxifen. Similar data were obtained in human placental microsomes. Endoxifen and N-desmethyl-tamoxifen were found to be potent inhibitors of aromatase. Inhibition by these tamoxifen metabolites may contribute to the variability in clinical effects of tamoxifen in patients with breast cancer. Relationships between tamoxifen metabolite concentrations and clinical outcomes may be complex

  5. A novel method for measuring aromatase activity in tissue samples by determining estradiol concentrations.

    PubMed

    Tinwell, H; Rascle, J B; Colombel, S; Al Khansa, I; Freyberger, A; Bars, R

    2011-07-01

    Increasing scrutiny of endocrine disrupters has led to changes to European pesticide and biocide legislation and to the introduction of the Endocrine Disrupter Screening Program by the US EPA. One element of endocrine disrupter identification is to determine its effects on aromatase, but most available assays are limited as they depend on tritiated water production to indicate enzyme activity. Whilst acceptable for determining aromatase effects using a cell-free approach, this method is unreliable for cell or tissue-based investigations as other cytochrome P-450 isoenzyme activities can similarly produce tritiated water and consequently confound interpretation of the aromatase data. To address this lack of specificity an assay directly measuring the final estrogen product by incubating rat tissue protein with testosterone and measuring the resultant estradiol concentration was developed. Using this approach we demonstrated marked increases in enzyme activity in pregnant rat ovary samples and dose-related inhibitions when incubating non-pregnant rat ovary samples with known aromatase inhibitors. Hepatic aromatase activity was investigated using our method and by tritiated water production with microsomes from rats dosed with the antiandrogen 1,1-dichloro-2,2-bis(4 chlorophenyl)ethane. Additional cytochrome P-450s were also measured. Treatment-related increased tritiated water production and general hepatic enzyme activity were recorded but estradiol was not increased, indicating that the increased tritiated water was due to general enzyme activity and not aromatase activity. A simple and specific method has been developed that can detect aromatase inhibition and induction, which when applied to tissue samples, provides a means of generating relevant animal data concerning chemical effects on the aromatase enzyme.

  6. Modulation of Aromatase by Phytoestrogens

    PubMed Central

    Lephart, Edwin D.

    2015-01-01

    The aromatase enzyme catalyzes the conversion of androgens to estrogens in many human tissues. Estrogens are known to stimulate cellular proliferation associated with certain cancers and protect against adverse symptoms during the peri- and postmenopausal intervals. Phytoestrogens are a group of plant derived naturally occurring compounds that have chemical structures similar to estrogen. Since phytoestrogens are known to be constituents of animal/human food sources, these compounds have received increased research attention. Phytoestrogens may contribute to decreased cancer risk by the inhibition of aromatase enzyme activity and CYP19 gene expression in human tissues. This review covers (a) the aromatase enzyme (historical descriptions on function, activity, and gene characteristics), (b) phytoestrogens in their classifications and applications to human health, and (c) a chronological coverage of aromatase activity modulated by phytoestrogens from the early 1980s to 2015. In general, phytoestrogens act as aromatase inhibitors by (a) decreasing aromatase gene expression, (b) inhibiting the aromatase enzyme itself, or (c) in some cases acting at both levels of regulation. The findings presented herein are consistent with estrogen's impact on health and phytoestrogen's potential as anticancer treatments, but well-controlled, large-scale studies are warranted to determine the effectiveness of phytoestrogens on breast cancer and age-related diseases. PMID:26798508

  7. Aromatase Inhibitors and Other Compounds for Lowering Breast Cancer Risk

    MedlinePlus

    ... Cancer Risk and Prevention Aromatase Inhibitors for Lowering Breast Cancer Risk Aromatase inhibitors (drugs that lower estrogen levels) ... day. Can aromatase inhibitors lower the risk of breast cancer? Aromatase inhibitors are used mainly to treat hormone ...

  8. Suppression of aromatase activity in vitro by PCBs 28 and 105 and Aroclor 1221.

    PubMed

    Woodhouse, Amanda J; Cooke, Gerard M

    2004-08-30

    The effects of polychlorinated biphenyls (PCBs) on human cytochrome P450 aromatase activity in vitro were investigated using a commercially available microsomal fraction obtained from baculovirus infected insects that had been transfected with the human CYP19 gene and cytochrome P450 reductase. The assay measured the conversion of tritiated testosterone to estradiol in Tris buffer at pH 7.4. When aroclors, commercial preparations of PCBs, were added to aromatase assays at a 10 microM concentration, Aroclor 1221 caused a reduction in the aromatase activity, whereas other aroclors (1016, 1232, 1242, 1248, 1254, 1260, 5432, 5442 and 5460) were without effect. Further investigation of the effect of Aroclor 1221 on aromatase activity showed that the inhibition was dose dependent. When a reconstituted mixture (RM) of PCBs that represented the congeneric content of human milk was investigated, no inhibition of aromatase activity at the maximum treatment of 15.0 microM was observed. None of the congeners present in the reconstituted mixture, except PCB 28 and 105, affected P450 arom activity. PCB 28 showed a statistically significant inhibition of aromatase activity (P<0.05) at 1.5 and 15 microM and a significant inhibition of aromatase activity by PCB 105 was also observed, but only at 15 microM. In three separate kinetic analyses the Km(app) for aromatase was 64, 89 and 69 nM (mean 74 nM). In addition, PCB 28 resulted in an increase in the Km(app) without a significant effect on Vmax(app), suggesting competitive inhibition by this congener. This conclusion was supported by slope (Km(app)/Vmax(app) versus [inhibitor]) and intercept (1/Vmax(app) versus [inhibitor]) replots. The slope replots gave Ki(app) values for PCB 28 of 0.9, 1.3 and 2.0 microM (mean 1.4 microM), whereas intercept replots were almost horizontal. Thus, PCB 28 is a competitive inhibitor of aromatase with a Ki(app) value approximately 20-fold the Km(app) value. Based on these studies, we conclude that

  9. Placental steroid hormone biosynthesis in primate pregnancy.

    PubMed

    Albrecht, E D; Pepe, G J

    1990-02-01

    and thus the metabolism of estradiol, while androgens exert marked inhibitory effects on placental progesterone formation, at least in vitro. Not surprisingly, the regulation of placental progesterone and estrogen formation also is multifactorial. Thus, aromatase activity is stimulated synergistically by cAMP and phorbol esters, an effect that is suppressed by peptide growth factors. Therefore, the autocrine/paracrine and multifactorial regulation of hormone biosynthesis that has been relatively well documented in other tissues should be recognized as important in the primate placenta. Finally, the basic mechanisms underlying regulation of steroidogenesis within the fetoplacental unit during primate pregnancy appear similar, in important ways, to those of widely used laboratory animals, such as the rat and rabbit.(ABSTRACT TRUNCATED AT 400 WORDS)

  10. Aromatase and breast cancer.

    PubMed

    Brodie, A; Sabnis, G; Jelovac, D

    2006-12-01

    Several aromatase inhibitors and also new antiestrogens are now available for treating breast cancer. We have developed a model to compare the antitumor efficacy of these agents and to explore strategies for their optimal use. Results from the model have been predictive of clinical outcome. In this model, tumors are grown in ovariectomized, immunodeficient mice from MCF-7 human breast cancer cells transfected with the aromatase gene (MCF-7Ca). The possibility that blockade of estrogen action and estrogen synthesis may be synergistic was explored by treating mice with the aromatase inhibitor letrozole and the antiestrogen tamoxifen alone and in combination. The results indicated that letrozole alone was better than all other treatments. In addition, when tamoxifen treatment was no longer effective, tumor growth was significantly reduced in mice switched to letrozole treatment. However, tumors ultimately began to grow during continued treatment. To investigate the mechanisms by which tumors eventually adapt and grow during letrozole treatment, we determined the expression of signaling proteins in tumors during the course of letrozole treatment compared to the tumors of control mice. Tumors initially up-regulated the ER while responding to treatment, but subsequently receptor levels decreased in tumors unresponsive to letrozole. Also, Her-2 and adapter proteins (p-Shc and Grb-2) as well as all of the signaling proteins in the MAPK cascade (p-Raf, p-Mekl/2, and p-MAPK), but not in the Pl3/Akt pathway, were increased in tumors no longer responsive to letrozole. To investigate whether sensitivity to letrozole could be regained, cells were isolated from the letrozole resistant tumors (LTLT) and treated with inhibitors of the MAPKinase pathway (PD98059 and UO126). These compounds reduced MAPK activity and increased ER expression. EGFR/Her-2 inhibitors, gefitinib and AEE78S although not effective in the parental MCF-70a cells, restored the sensitivity of LTLT cells to

  11. Genetics Home Reference: aromatase deficiency

    MedlinePlus

    ... development, aromatase converts androgens to estrogens in the placenta, which is the link between the mother's blood supply and the fetus. This conversion in the placenta prevents androgens from directing sexual development in female ...

  12. Sequencing of aromatase inhibitors

    PubMed Central

    Bertelli, G

    2005-01-01

    Since the development of the third-generation aromatase inhibitors (AIs), anastrozole, letrozole and exemestane, these agents have been the subject of intensive research to determine their optimal use in advanced breast cancer. Not only have they replaced progestins in second-line therapy and challenged the role of tamoxifen in first-line, but there is also evidence for a lack of cross-resistance between the steroidal and nonsteroidal AIs, meaning that they may be used in sequence to obtain prolonged clinical benefit. Many questions remain, however, as to the best sequence of the two types of AIs and of the other available agents, including tamoxifen and fulvestrant, in different patient groups. PMID:16100523

  13. A three-dimensional model of CYP19 aromatase for structure-based drug design.

    PubMed

    Karkola, Sampo; Höltje, Hans-Dieter; Wähälä, Kristiina

    2007-01-01

    Aromatase (CYP450(arom), CYP19) is an enzyme responsible for converting the aliphatic androgens androstenedione and testosterone to the aromatic estrogens estrone and estradiol, respectively. These endogenous hormones are a key factor in cancer tumor formation and proliferation through a cascade starting from estrogen binding to estrogen receptor. To interfere with the overproduction of estrogens especially in tumor tissue, it is possible to inhibit aromatase activity. This can be achieved using aromatase inhibitors. In order to design novel aromatase inhibitors, it is necessary to have an understanding of the active site of aromatase. As no crystal structure of the enzyme has yet been published, we built a homology model of aromatase using the first crystallized mammalian cytochrome enzyme, rabbit 21-progesterone hydroxylase 2C5, as a template structure. The initial model was validated with exhaustive molecular dynamics simulation with and without the natural substrate androstenedione. The resulting enzyme-substrate complex shows very good stability and only two of the residues are in disallowed regions in a Ramachandran plot.

  14. Genetics Home Reference: aromatase excess syndrome

    MedlinePlus

    ... Sources for This Page Fukami M, Shozu M, Ogata T. Molecular bases and phenotypic determinants of aromatase ... T, Nishigaki T, Yokoya S, Binder G, Horikawa R, Ogata T. Aromatase excess syndrome: identification of cryptic duplications ...

  15. Aromatase expression and role of estrogens in male gonad : a review

    PubMed Central

    Carreau, Serge; Lambard, Sophie; Delalande, Christelle; Denis-Galeraud, Isabelle; Bilinska, Barbara; Bourguiba, Sonia

    2003-01-01

    The ability of the testis to convert irreversibly androgens into estrogens is related to the presence of a microsomal enzymatic complex named aromatase, which is composed of a specific glycoprotein, the cytochrome P450 aromatase (P450arom) and an ubiquitous reductase. The aromatase gene is unique in humans and contained 18 exons, 9 of them being translated. In the rat testis we have immunolocalized the P450arom not only in Leydig cells but also in germ cells and especially in elongated spermatids. Related to the stage of germ cell maturation, we have shown that the level of P450arom mRNA transcripts decreases, it is much more abundant in pachytene spermatocytes and round spermatids than in mature germ cells whereas the aromatase activity is 2–4 fold greater in spermatozoa when compared to the younger germ cells. Using a highly specific quantitative competitive RT-PCR method we have evidenced that several factors direct the expression of the aromatase gene in Leydig cells, Sertoli cells, pachytene spermatocytes and round spermatids, and it is obvious that promoter PII is the main one but other promoters could be concerned. In the bank-vole testis we have observed a positive correlation between a fully developed spermatogenesis and a strong immunoreactivity for both P450arom and estrogen receptor β not only in Sertoli cells but also in pachytene spermatocytes and round spermatids. Our recent data obtained from ejaculated human spermatozoa demonstrate the presence of aromatase both in terms of mRNA and protein, and in addition, we suggest that aromatase could be involved in the acquisition of sperm motility. Indeed in men the congenital aromatase deficiency is associated with severe bone maturation problems and sterility. Together with the widespread distribution of estrogen receptors in testicular cells these data clearly show that estrogens play a physiological role in the regulation of spermatogenesis in mammals. PMID:12747806

  16. Expression profile of the aromatase enzyme in the Xenopus brain and localization of estradiol and estrogen receptors in each tissue.

    PubMed

    Iwabuchi, Junshin; Koshimizu, Kouta; Nakagawa, Tadahiko

    2013-12-01

    Estradiol (E2) with the strongest bioactivity of the estrogens, is synthesized by the cytochrome p450 aromatase enzyme and plays a key role in sex differentiation of the vertebrate's gonads. In Xenopus, aromatase mRNA is highly expressed in the brain rather than in the gonad during sex differentiation. In this study, we analyzed the stage change, tissue specificity, and localization of the aromatase expression in the Xenopus brain. Regardless of the sex difference, expression level of aromatase was remarkably higher in the brain than in other tissues during the early stages of brain morphogenesis and was observed in the formation regions of the choroid plexus of cerebral ventricle and the paleocortex and olfactory bulb of the prosencephalon. However, E2 concentrations in each tissue indicated a different localization of aromatase and were seen in the heart at almost double the level as seen in the brain. In addition, while aromatase expression level in the brain was increasing, E2 in the whole body began to increase at the same stage. Since the expression level of estrogen receptor α also corresponded to localization of E2, these results may imply that the E2 synthesized by the high aromatase expression in the choroid plexus, which generates cerebrospinal fluid, circulates to the heart and acts through ERα.

  17. Natural products as aromatase inhibitors.

    PubMed

    Balunas, Marcy J; Su, Bin; Brueggemeier, Robert W; Kinghorn, A Douglas

    2008-08-01

    With the clinical success of several synthetic aromatase inhibitors (AIs) in the treatment of postmenopausal estrogen receptor-positive breast cancer, researchers have also been investigating the potential of natural products as AIs. Natural products from terrestrial and marine organisms provide a chemically diverse array of compounds not always available through current synthetic chemistry techniques. Natural products that have been used traditionally for nutritional or medicinal purposes (e.g., botanical dietary supplements) may also afford AIs with reduced side effects. A thorough review of the literature regarding natural product extracts and secondary metabolites of plant, microbial, and marine origin that have been shown to exhibit aromatase inhibitory activity is presented herein.

  18. Cytotoxic effects and aromatase inhibition by xenobiotic endocrine disrupters alone and in combination

    SciTech Connect

    Benachour, Nora; Moslemi, Safa; Sipahutar, Herbert; Seralini, Gilles-Eric . E-mail: criigen@unicaen.fr

    2007-07-15

    Xenobiotics may cause long-term adverse effects in humans, especially at the embryonic level, raising questions about their levels of exposure, combined effects, and crucial endpoints. We are interested in the possible interactions between xenobiotic endocrine disrupters, cellular viability and androgen metabolism. Accordingly, we tested aroclor 1254 (A1254), atrazine (AZ), o,p'-DDT, vinclozolin (VZ), p,p'-DDE, bisphenol A (BPA), chlordecone (CD), nonylphenol (NP), tributylin oxide (TBTO), and diethylstilbestrol (DES) for cellular toxicity against human embryonic 293 cells, and activity against cellular aromatase, but also on placental microsomes and on the purified equine enzyme. Cellular viability was affected in 24 h by all the xenobiotics with a threshold at 50 {mu}M (except for TBTO and DES, 10 {mu}M threshold), and aromatase was inhibited at non-toxic doses. In combination synergism was observed reducing the threshold values of toxicity to 4-10 {mu}M, and aromatase activity by 50% in some cases. In placental microsomes the most active xenobiotics rapidly inhibited microsomal aromatase in a manner independent of NADPH metabolism. Prolonged exposures to low doses in cells generally amplified by 50 times aromatase inhibition. These xenobiotics may act by inhibition of the active site or by allosteric effects on the enzyme. Bioaccumulation is a feature of some xenobiotics, especially chlordecone, DDT and DDE, and low level chronic exposures can also affect cell signaling mechanisms. This new information about the mechanism of action of these xenobiotics will assist in improved molecular design with a view to providing safer compounds for use in the (human) environment.

  19. Cytotoxic effects and aromatase inhibition by xenobiotic endocrine disrupters alone and in combination.

    PubMed

    Benachour, Nora; Moslemi, Safa; Sipahutar, Herbert; Seralini, Gilles-Eric

    2007-07-15

    Xenobiotics may cause long-term adverse effects in humans, especially at the embryonic level, raising questions about their levels of exposure, combined effects, and crucial endpoints. We are interested in the possible interactions between xenobiotic endocrine disrupters, cellular viability and androgen metabolism. Accordingly, we tested aroclor 1254 (A1254), atrazine (AZ), o,p'-DDT, vinclozolin (VZ), p,p'-DDE, bisphenol A (BPA), chlordecone (CD), nonylphenol (NP), tributylin oxide (TBTO), and diethylstilbestrol (DES) for cellular toxicity against human embryonic 293 cells, and activity against cellular aromatase, but also on placental microsomes and on the purified equine enzyme. Cellular viability was affected in 24 h by all the xenobiotics with a threshold at 50 microM (except for TBTO and DES, 10 microM threshold), and aromatase was inhibited at non-toxic doses. In combination synergism was observed reducing the threshold values of toxicity to 4-10 microM, and aromatase activity by 50% in some cases. In placental microsomes the most active xenobiotics rapidly inhibited microsomal aromatase in a manner independent of NADPH metabolism. Prolonged exposures to low doses in cells generally amplified by 50 times aromatase inhibition. These xenobiotics may act by inhibition of the active site or by allosteric effects on the enzyme. Bioaccumulation is a feature of some xenobiotics, especially chlordecone, DDT and DDE, and low level chronic exposures can also affect cell signaling mechanisms. This new information about the mechanism of action of these xenobiotics will assist in improved molecular design with a view to providing safer compounds for use in the (human) environment.

  20. EVALUATION OF THE AROMATASE INHIBITOR FADROZOLE IN A SHORT-TERM REPRODUCTION ASSAY WITH THE FATHEAD MINNOW (PIMEPHALES PROMELAS)

    EPA Science Inventory

    Cytochrome P450 aromatase is a key enzyme in vertebrate steroidogenesis, catalyzing the conversion of C19 androgens to C18 estrogens such a B-estradiol (E2). The objective of this study was to assess effects of the CYP inhibitor fadrozole on fathead minnow reproductive endocrinol...

  1. Substituted androstanes as aromatase inhibitors

    NASA Astrophysics Data System (ADS)

    Levina, Inna S.

    1998-11-01

    The synthesis and structure-activity relationships of inhibitors of steroid aromatase which catalyses the last stage of a multistep biotransformation of cholesterol into estrogens, viz., aromatisation of C19-steroids into C18-phenolic steroids, are discussed. Compounds of the androstane series which are structurally related to the natural substrate, viz., androst-4-ene-3,17-dione, are the subjects of consideration. The review encompasses problems of synthesis of various substituted androstanes and their aromatase-inhibiting activities and structural requirements for selective specific aromatase inhibitors based on in vitro and in vivo structure-activity studies of compounds synthesised, their biological properties and the results of clinical trials. Special attention is paid to practical applications of aromatase inhibitors in the treatment of hormone-dependent mammary and ovarian tumours as well as benign prostatic tumours. In writing this report, the author has used all the information currently available in the chemical, biochemical, endocrinological and medicinal literature as well as in patents. The bibliography includes 173 references.

  2. [Estrogen formation in the central nervous system and characteristics of aromatase of rat hypothalamus].

    PubMed

    Takezawa, Y; Fukabori, Y; Honma, S

    1991-02-20

    Estrogen formation from androst-4-ene-3,17-dione and its kinetics were studied using microsomes from rat hypothalamus. [4-14C] androst-4-ene-3,17-dione and a homogenate of rat hypothalamus were incubated in the presence of NADPH at 37 degrees C for 3 hrs. The estrogen fraction was extracted from the incubation mixture with ethyl acetate, purified by column chromatography on Sephadex LH-20 and Bond Elut C18, and separated into estrone and estradiol fractions by HPLC. In analysis of the trimethylsilyl (TMS) derivatives of each fraction by gas chromatography-mass spectrometry (GC-MS), the molecular ion peak of the estrone fraction appeared at m/z 344, within 2 amu of that for the TMS derivative of natural estrone. The retention time of the estrone fraction derivative was 11.6 min, the same as that of natural estrone. 14C-estrone was thus concluded to be biosynthesized from [4-14C]-androst-4-ene-3,17-dione in rat hypothalamus. The kinetics of the aromatase of rat hypothalamic tissue was studied by measuring 3H2O released from [1 beta-3H]-androst-4-ene-3,17-dione and estrone as the estrogen product by measured gas chromatography selected ion monitoring (GC-SIM). High correlation was found between 3H2O release and estrone measured by GC-SIM (r = 0.97). Aromatase activity was linear with respect to incubation time and quantity of tissue. Km and Vmax were 30.3 nM and 7.98 fmol estrogen/h/mg of wet tissue, respectively. 4-hydroxyandrostenedione (4-OH-A) suppressed the activity of aromatase in both rat hypothalamic and human placental tissue in a concentration-dependent manner. Polyclonal IgG to human placental aromatase also suppressed aromatase activity of human placental tissue, but only slightly suppressed that of rat hypothalamus. The molecular structure of aromatase in rat hypothalamus was thus concluded to differ from that in human placenta.

  3. Integrated approach to explore the mechanisms of aromatase inhibition and recovery in fathead minnows (Pimephales promelas).

    PubMed

    Garcia-Reyero, Natàlia; Ekman, Drew R; Habib, Tanwir; Villeneuve, Daniel L; Collette, Timothy W; Bencic, David C; Ankley, Gerald T; Perkins, Edward J

    2014-07-01

    Aromatase, a member of the cytochrome P450 superfamily, is a key enzyme in estradiol synthesis that catalyzes the aromatization of androgens into estrogens in ovaries. Here, we used an integrated approach to assess the mechanistic basis of the direct effects of aromatase inhibition, as well as adaptation and recovery processes in fish. We exposed female fathead minnows (Pimephales promelas) via the water to 30 μg/L of a model aromatase inhibitor, fadrozole, during 8 days (exposure phase). Fish were then held in clean water for 8 more days (recovery phase). Samples were collected at 1, 2, 4, and 8 days of both the exposure and the recovery phases. Transcriptomics, metabolomics, and network inference were used to understand changes and infer connections at the transcript and metabolite level in the ovary. Apical endpoints directly indicative of endocrine function, such as plasma estradiol, testosterone, and vitellogenin levels were also measured. An integrated analysis of the data revealed changes in gene expression consistent with increased testosterone in fadrozole-exposed ovaries. Metabolites such as glycogen and taurine were strongly correlated with increased testosterone levels. Comparison of in vivo and ex vivo steroidogenesis data suggested the accumulation of steroidogenic enzymes, including aromatase, as a mechanism to compensate for aromatase inhibition.

  4. Mechanism-based categorization of aromatase inhibitors: a potential discovery and screening tool.

    PubMed

    Petkov, P I; Temelkov, S; Villeneuve, D L; Ankley, G T; Mekenyan, O G

    2009-10-01

    Cytochrome P450 aromatase is a key steroidogenic enzyme that converts androgens to estrogens in vertebrates. There is much interest in aromatase inhibitors (AIs) both because of their use as pharmaceuticals in the treatment of estrogen-sensitive breast cancers, and because a number of environmental contaminants can act as AIs, thereby disrupting endocrine function in humans and wildlife through suppression of circulating estrogen levels. The goal of the current work was to develop a mechanism-based structure-activity relationship (SAR) categorization framework highlighting the most important chemical structural features responsible for inhibition of aromatase activity. Two main interaction mechanisms were discerned: steroidal and non-steroidal. The steroid scaffold is most prominent when the structure of the target chemical is similar to the natural substrates of aromatase - androstenedione and testosterone. Chemicals acting by non-steroidal mechanism(s) possess a heteroatom (N, O, S) able to coordinate the heme iron of the cytochrome P450, and thus interfere with steroid hydroxylation. The specific structural boundaries controlling AI for both analyzed mechanisms were defined, and a software tool was developed that allowed a decision tree (profile) to be built discriminating AIs by mechanism and potency. An input chemical follows a profiling path and the structure is examined at each step to decide whether it conforms with the structural boundaries implemented in the decision tree node. Such a system would aid drug discovery efforts, as well as provide a screening tool to detect environmental contaminants that could act as AIs.

  5. Fetal safety profile of aromatase inhibitors: Animal data.

    PubMed

    Tiboni, Gian Mario; Ponzano, Adalisa

    2016-12-01

    Aromatase inhibitors (AIs) are a class of drugs that act by blocking the production of estrogens from androgens. The current review concentrates on the prenatal developmental toxicity of AIs in experimental models. Available data indicate that AIs may affect pregnancy at human therapeutic or lower doses. The window of vulnerability to AIs is not limited to organogenesis, but also includes the preimplantation stage and fetal periods. Decreased embryo/fetal survival was the prominent treatment-related effect. Morphological anomalies noted in fetuses exposed to AIs included skeletal anomalies, abnormal head morphology, increased ano-genital distance in female fetuses, and minor urinary tract system anomalies. Placental enlargement was consistently reported in rats and non-human primates after maternal treatment with several AIs. In conclusion, data from basic scientific research suggest that low intensity exposure to AIs applied during a wide gestational window can profoundly affect prenatal development.

  6. Nicotine, cotinine, and anabasine inhibit aromatase in human trophoblast in vitro.

    PubMed Central

    Barbieri, R L; Gochberg, J; Ryan, K J

    1986-01-01

    Epidemiologic studies suggest that women who smoke have lower endogenous estrogen than nonsmokers. To explore the possible link between cigarette smoking and decreased endogenous estrogens, we have examined the effects of constituents of tobacco on estrogen production in human choriocarcinoma cells and term placental microsomes. In choriocarcinoma cell cultures, nicotine, cotinine (a major metabolite of nicotine), and anabasine (a minor component of cigarette tobacco) all inhibited androstenedione conversion to estrogen in a dose-dependent fashion. Removal of nicotine, cotinine, and anabasine from the culture medium resulted in the complete reversal of the inhibition of aromatase. In the choriocarcinoma cell cultures, a supraphysiologic concentration of androstenedione (73 microM) in the culture medium blocked the inhibition of aromatase caused by nicotine, cotinine, and anabasine. In preparations of term placental microsomes, nicotine, cotinine, and anabasine inhibited the conversion of testosterone to estrogen. Kinetic analysis demonstrated the inhibition to be competitive with respect to the substrate. These findings suggest that some nicotinic alkaloids directly inhibit aromatase. This mechanism may explain, in part, the decreased estrogen observed in women who smoke. PMID:3711333

  7. Structure-activity relationships of 2alpha-substituted androstenedione analogs as aromatase inhibitors and their aromatization reactions.

    PubMed

    Numazawa, Mitsuteru; Handa, Wakako; Hasegawa, Chie; Takahashi, Madoka

    2005-12-01

    Aromatase catalyzes the conversion of androstenedione (1a, AD) to estrone through three sequential oxygenations of the 19-methyl group. To gain insight into the spatial nature of the AD binding (active) site of aromatase in relation to the catalytic function of the enzyme, we tested for the ability of 2alpha-substituted (halogeno, alkyl, hydroxy, and alkoxy) ADs (1b-1i) to inhibit aromatase in human placental microsomes as well as their ability to serve as a substrate for the enzyme. All of the steroids inhibited the enzyme in a competitive manner with the apparent K(i)'s ranging from 45 to 1150 nM. 2alpha-Halogeno (F, Cl, and Br) and 2alpha-alkyl (CH3 and CH2CH3) steroids 1b-1f were powerful to good inhibitors (Ki=45-171 nM) whereas steroids 1g-1i, having an oxygen function (hydroxy or alkoxy) at C-2alpha, were poor inhibitors (Ki=670-1150 nM). Aromatization of some of the steroids with placental microsomes was analyzed by gas chromatography-mass spectrometry, indicating that the aromatization rate of the bromide 1d was about two-fold that of the natural substrate AD and that of 2alpha-methoxide 1h was similar to that of AD. Kinetic analysis of the aromatization of androgens revealed that a good substrate was not essentially a good inhibitor for aromatase.

  8. Anti-aromatase chemicals in red wine.

    PubMed

    Eng, E T; Williams, D; Mandava, U; Kirma, N; Tekmal, R R; Chen, S

    2002-06-01

    Estrogen synthesized in situ plays a more important role in breast cancer cell proliferation than does circulating estrogen. Aromatase is the enzyme that converts androgen to estrogen and is expressed at a higher level in breast cancer tissue than in surrounding noncancer tissue. A promising route of chemoprevention against breast cancer may be through the suppression of in situ estrogen formation using aromatase inhibitors. A diet high in fruits and vegetables may reduce the incidence of breast cancer, because they contain phytochemicals that can act as aromatase inhibitors. In our previous studies, we found that grapes and wine contain potent phytochemicals that can inhibit aromatase. We show that red wine was more effective than white wine in suppressing aromatase activity. Interestingly, our results from white wine studies suggest a weak inductive effect of alcohol on aromatase activity. On the other hand, the potent effect of anti-aromatase chemicals in red wine overcomes the weak inductive effect of alcohol in wine. Several purification procedures were performed on whole red wine to separate active aromatase inhibitors from non-active compounds. These techniques included liquid-liquid extraction, silica gel chromatography, various solid phase extraction (SPE) columns, and high performance liquid chromatography. An active Pinot Noir red wine SPE C18 column fraction (20% acetonitrile:water) was more effective than complete Pinot Noir wine in suppressing aromatase assay. This red wine extract was further analyzed in a transgenic mouse model in which aromatase was over-expressed in mammary tissue. Our gavaged red wine extract completely abrogated aromatase-induced hyperplasia and other neoplastic changes in mammary tissue. These results suggest that red wine or red wine extract may be a chemopreventive diet supplement for postmenopausal women who have a high risk of breast cancer. Further research is underway to purify and characterize the active compounds in red

  9. Natural Products as Aromatase Inhibitors

    PubMed Central

    Balunas, Marcy J.; Su, Bin; Brueggemeier, Robert W.; Kinghorn, A. Douglas

    2010-01-01

    With the clinical success of several synthetic aromatase inhibitors (AIs) in the treatment of postmenopausal estrogen receptor-positive breast cancer, researchers have also been investigating also the potential of natural products as AIs. Natural products from terrestrial and marine organisms provide a chemically diverse array of compounds not always available through current synthetic chemistry techniques. Natural products that have been used traditionally for nutritional or medicinal purposes (e.g., botanical dietary supplements) may also afford AIs with reduced side effects. A thorough review of the literature regarding natural product extracts and secondary metabolites of plant, microbial, and marine origin that have been shown to exhibit aromatase inhibitory activity is presented herein. PMID:18690828

  10. The red wine polyphenol resveratrol displays bilevel inhibition on aromatase in breast cancer cells.

    PubMed

    Wang, Yun; Lee, Kai Woo; Chan, Franky L; Chen, Shiuan; Leung, Lai K

    2006-07-01

    Estrogen plays a crucial role in the development of breast cancer, and the inhibition of estrogen synthesis has been an important target for the prevention and treatment of this disease. The rate-limiting reaction of the hormone biosynthesis is catalyzed by cytochrome P450 (CYP) 19 enzyme or aromatase. It has been of genuine interest to uncover an aromatase-inhibitory compound from a dietary source. Resveratrol is a polyphenolic compound that can be isolated from grape peel. Because of its structural resemblance to estrogen, resveratrol's agonistic and antagonistic properties on estrogen receptor have been examined and demonstrated. In the present study, the effect of resveratrol on the expression and enzyme activity of aromatase was investigated. By assaying on MCF-7 cells stably transfected with CYP19 (MCF-7aro cells), resveratrol inhibited the aromatase activity with an IC(50) value of 25 microM. Kinetic analysis indicated that both competitive and noncompetitive inhibition might be involved. The administration of 10 nmol/l testosterone-a substrate of aromatase-produced a 50% increase in the MCF-7aro cell number. This cell proliferation specifically induced by testosterone was significantly reduced by 10 microM resveratrol. In addition, 50 microM resveratrol significantly reduced the CYP19-encoding mRNA abundance in SK-BR-3 cells. The transcriptional control of CYP19 gene is tissue specific, and promoter regions I.3 and II have previously been shown to be responsible for CYP19 expression in breast cancer cells. Luciferase reporter gene assays revealed that resveratrol could repress the transcriptional control dictated by the promoter regulation. The present study illustrated that pharmacological dosage of resveratrol inhibited aromatase at both the enzyme and mRNA levels.

  11. Transgenic Chickens Overexpressing Aromatase Have High Estrogen Levels but Maintain a Predominantly Male Phenotype.

    PubMed

    Lambeth, Luke S; Morris, Kirsten R; Wise, Terry G; Cummins, David M; O'Neil, Terri E; Cao, Yu; Sinclair, Andrew H; Doran, Timothy J; Smith, Craig A

    2016-01-01

    Estrogens play a key role in sexual differentiation of both the gonads and external traits in birds. The production of estrogen occurs via a well-characterized steroidogenic pathway, which is a multistep process involving several enzymes, including cytochrome P450 aromatase. In chicken embryos, the aromatase gene (CYP19A1) is expressed female-specifically from the time of gonadal sex differentiation. Ectopic overexpression of aromatase in male chicken embryos induces gonadal sex reversal, and male embryos treated with estradiol become feminized; however, this is not permanent. To test whether a continuous supply of estrogen in adult chickens could induce stable male to female sex reversal, 2 transgenic male chickens overexpressing aromatase were generated using the Tol2/transposase system. These birds had robust ectopic aromatase expression, which resulted in the production of high serum levels of estradiol. Transgenic males had female-like wattle and comb growth and feathering, but they retained male weights, displayed leg spurs, and developed testes. Despite the small sample size, this data strongly suggests that high levels of circulating estrogen are insufficient to maintain a female gonadal phenotype in adult birds. Previous observations of gynandromorph birds and embryos with mixed sex chimeric gonads have highlighted the role of cell autonomous sex identity in chickens. This might imply that in the study described here, direct genetic effects of the male chromosomes largely prevailed over the hormonal profile of the aromatase transgenic birds. This data therefore support the emerging view of at least partial cell autonomous sex development in birds. However, a larger study will confirm this intriguing observation.

  12. Time-dependent aromatase inactivation by 4 beta,5 beta-epoxides of the natural substrate androstenedione and its 19-oxygenated analogs.

    PubMed

    Numazawa, Mitsuteru; Yoshimura, Akiko; Tachibana, Mii; Shelangouski, Momoko; Ishikawa, Maya

    2002-03-01

    Aromatase catalyzes the conversion of androgens to estrogens through three sequential oxygenations. To gain insight into the catalytic function of aromatase and its aromatization mechanism, we studied the inhibition of human placental aromatase by 4 beta,5 beta-epoxyandrostenedione (5) as well as its 19-hydroxy and 19-oxo derivatives (6 and 7, respectively), and we also examined the biochemical aromatization of these steroids. All of the epoxides were weak competitive inhibitors of aromatase with apparent K(i) values ranging from 5.0 microM to 30 microM. The 19-methyl and 19-oxo compounds 5 and 7 inactivated aromatase in a time-dependent manner with k(inact) of 0.048 and 0.110 min(-1), respectively, in the presence of NADPH. In the absence of NADPH, only the former inhibited aromatase with a k(inact) of 0.091 min(-1). However, 19-hydroxy steroid 6 did not cause irreversible inactivation either in the presence or absence of NADPH. Gas chromatography-mass spectrometric analysis of the metabolite produced by a 5-min incubation of the three epoxides with human placental microsomes in the presence of NADPH under air revealed that all three compounds were aromatized to produce estradiol with rates of 8.82, 0.51, and 1.62 pmol/min/mg protein for 5, 6, and 7, respectively. In each case, the aromatization was efficiently prevented by 19-hydroxyandrost-4-en-17-one, a potent aromatase inhibitor. On the basis of the aromatization and inactivation results, it seems likely that the two pathways, aromatization and inactivation, may proceed, in part, through a common intermediate, 19-oxo compound 7, although they may be principally different.

  13. Aromatase Inhibition in a Transcriptional Network Context

    EPA Science Inventory

    A variety of chemicals in the environment have the potential to inhibit aromatase, an enzyme critical to estrogen synthesis. We examined the responses of female fathead minnow ovaries (FHM, Pimephales promelas) to a model aromatase inhibitor, fadrozole, using a transcriptional ne...

  14. Aromatase inhibitors: structural features and biochemical characterization.

    PubMed

    Hong, Yanyan; Chen, Shiuan

    2006-11-01

    Aromatase is the enzyme synthesizing estrogens from androgens. In estrogen-dependent breast tumors, estrogens induce the expression of growth factors responsible for cancer cell proliferation. In situ estrogen synthesis by aromatase "is thought to play a key role in the promotion of breast cancer growth. Aromatase inhibitors (AIs) provide new approaches for the prevention and treatment of breast cancer by inhibiting estrogen biosynthesis. Through reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemical techniques, aromatase has been found to be expressed in many endocrine tissues and tumors originating from these tissues. Unexpectedly, this enzyme is now known to also be expressed in liver, lung, and colon cancers. Such findings suggest a potential role for endocrine manipulation of these types of cancer using AIs. Three Food and Drug Administration (FDA)-approved AIs, anastrozole (Arimidex), letrozole (Femara), and exemestane (Aromasin), effectively challenging tamoxifen, have been used as first-line drugs in the treatment of hormone-dependent breast cancer, and possibly other aromatase-expressing cancers. In addition, natural anti-aromatase chemicals, such as flavones and coumarins, have been identified. Efforts to develop new lines of AIs derived from these phytochemicals have been initiated in several laboratories. Finally, significant progress has been made in the understanding of the structure-function relationship of aromatase. Such information has helped the examination of binding characteristics of AIs, the evaluation of reaction mechanism of aromatase, and the explanation of the molecular basis for a low catalytic activity of the natural variant, M364T.

  15. X-ray structure of human aromatase reveals an androgen-specific active site.

    PubMed

    Ghosh, Debashis; Griswold, Jennifer; Erman, Mary; Pangborn, Walter

    2010-02-28

    Aromatase is a unique cytochrome P450 that catalyzes the removal of the 19-methyl group and aromatization of the A-ring of androgens for the synthesis of estrogens. All human estrogens are synthesized via this enzymatic aromatization pathway. Aromatase inhibitors thus constitute a frontline therapy for estrogen-dependent breast cancer. Despite decades of intense investigation, this enzyme of the endoplasmic reticulum membrane has eluded all structure determination efforts. We have determined the crystal structure of the highly active aromatase purified from human placenta, in complex with its natural substrate androstenedione. The structure shows the binding mode of androstenedione in the catalytically active oxidized high-spin ferric state of the enzyme. Hydrogen bond-forming interactions and tight packing hydrophobic side chains that complement the puckering of the steroid backbone provide the molecular basis for the exclusive androgenic specificity of aromatase. Locations of catalytic residues and water molecules shed new light on the mechanism of the aromatization step. The structure also suggests a membrane integration model indicative of the passage of steroids through the lipid bilayer.

  16. Aromatase inhibitors and bone loss.

    PubMed

    Perez, Edith A; Weilbaecher, Katherine

    2006-08-01

    The aromatase inhibitors (AIs) anastrozole (Arimidex), letrozole (Femara), and exemestane (Aromasin) are significantly more effective than the selective estrogen-receptor modulator (SERM) tamoxifen in preventing recurrence in estrogen receptor-positive early breast cancer. Aromatase inhibitors are likely to replace SERMs as first-line adjuvant therapy for many patients. However, AIs are associated with significantly more osteoporotic fractures and greater bone mineral loss. As antiresorptive agents, oral and intravenous bisphosphonates such as alendronate (Fosamax), risedronate (Actonel), ibandronate (Boniva), pamidronate (Aredia), and zoledronic acid (Zometa) have efficacy in preventing postmenopausal osteoporosis, cancer treatment-related bone loss, or skeletal complications of metastatic disease. Clinical practice guidelines recommend baseline and annual follow-up bone density monitoring for all patients initiating AI therapy. Bisphosphonate therapy should be prescribed for patients with osteoporosis (T score < -2.5) and considered on an individual basis for those with osteopenia (T score < -1). Modifiable lifestyle behaviors including adequate calcium and vitamin D intake, weight-bearing exercise, and smoking cessation should be addressed. Adverse events associated with bisphosphonates include gastrointestinal toxicity, renal toxicity, and osteonecrosis of the jaw. These safety concerns should be balanced with the potential of bisphosphonates to minimize or prevent the debilitating effects of AI-associated bone loss in patients with early, hormone receptor-positive breast cancer.

  17. Understanding the mechanisms of aromatase inhibitor resistance

    PubMed Central

    2012-01-01

    Aromatase inhibitors (AIs) have a central role in the treatment of breast cancer; however, resistance is a major obstacle to optimal management. Evidence from endocrine, molecular and pathological measurements in clinical material taken before and after therapy with AIs and data from clinical trials in which AIs have been given as treatment either alone or in combination with other targeted agents suggest diverse causes for resistance. These include inherent tumour insensitivity to oestrogen, ineffective inhibition of aromatase, sources of oestrogenic hormones independent of aromatase, activation of signalling by non-endocrine pathways, enhanced cell survival and selection of hormone-insensitive cellular clones during treatment. PMID:22277572

  18. Aromatase inhibitors from Urtica dioica roots.

    PubMed

    Gansser, D; Spiteller, G

    1995-04-01

    Methanolic extracts of stinging nettle (Urtica dioica L.) roots were investigated for aromatase inhibition. Enzyme inhibition was detected only after appropriate chromatographic separation. Inhibitory effects on aromatase could be demonstrated in vitro for a variety of compounds belonging to different classes. The following compounds developed weak to moderate activity: secoisolariciresinol, oleanolic and ursolic acid, (9Z,11E)-13-hydroxy-9,11-octadecadienoic acid, and 14-octacosanol (5). Inhibitory effects on aromatase have been known to date neither for pentacyclic triterpenes nor for secondary fatty alcohols. The potential physiological significance of the above findings is discussed. Compound 5 is a previously unknown constituent of plants.

  19. A time-course regulatory and kinetic expression study of steroid metabolizing enzymes by calcitriol in primary cultured human placental cells.

    PubMed

    Noyola-Martínez, Nancy; Halhali, Ali; Zaga-Clavellina, Verónica; Olmos-Ortiz, Andrea; Larrea, Fernando; Barrera, David

    2017-03-01

    1,25-dihydroxivitamin D3 (calcitriol), is a secoesteroid involved in several placental functions. In particular, we and others showed that calcitriol regulates peptides, proteins, cytokines and hormones production in human trophoblastic cells. On the other hand, calcitriol modifies the activity and expression of some steroidogenic enzymes, a process that is considered tissue-specific. However, the effects of calcitriol on the expression of enzymes involved in the synthesis of sex steroids in placental tissue have not yet been entirely studied. The aim of the present study was to investigate the effects of calcitriol upon gene expression of several steroid enzymes such as cytochrome P450scc (CYP11A1), type 1 3β-hydroxysteroid dehydrogenase(3β-HSDI), 17β-HSD3, 17α-hydroxylase/17,20 lyase (CYP17A1) and aromatase (CYP19A1) in primary cultures of human placental cells. Cell cultures were performed using placentas obtained immediately after delivery by caesarean section from normotensive healthy women and calcitriol effects were evaluated, at level of transcription, by qPCR. The results showed that: 1) from basal expression values of the five genes studied, 3β-HSDI was the most expressed gene (P<0.05); 2) basal expression of all enzymes was significantly higher in cultured syncytiotrophoblast than in cytotrophoblasts (P<0.05); 3) the presence of calcitriol in cultured trophoblast cells generally resulted in a stimulatory effect of CYP11A1, CYP19A1 and 17β-HSD3 gene expression at 3h of treatment whereas 3β-HSDI was induced at 6h (P<0.05). However, a time-dependent variable was also observed; 4) protein expression of CYP11A1 and 3β-HSDI were not modified significantly by calcitriol, however that of CYP19A1 was regulated in similar fashion as gene expression. In conclusion, calcitriol affected in a time-dependent manner the expression of steroids metabolizing enzymes in human placental cell cultures.

  20. Expression and localization of aromatase during fetal mouse testis development.

    PubMed

    Borday, Caroline; Merlet, Jorge; Racine, Chrystèle; Habert, René

    2013-01-01

    Les androgènes et les oestrogènes sont indispensables au développement et aux fonctions du testicule. Le testicule est particulièrement sensible aux perturbateurs endocriniens pendant le développement fœtal et beaucoup de perturbateurs endocriniens agissent en modifiant la balance oestrogènes/androgènes. Physiologiquement, cette balance est régulée par une cascade enzymatique qui convertit irréversiblement les androgènes en oestrogènes. Le composant principal de cette cascade est le cytochrome p450 19A1 (appelé couramment aromatase). Le but de ce travail a été d’étudier l’expression de l’aromatase testiculaire au cours du développement fœtal chez la souris.En utilisant une approche par RT-PCR et par western blot, nous avons montré que l’aromatase est exprimée dès 12,5 jours post-conception (jpc) et que l’expression est maximum à 17,5 jpc. Deux transcripts tronqués ont également été détectés par RT-PCR. La localisation cellulaire de l’aromatase a été étudiée par immunohistologie et par immunomarquage après séparation des cellules testiculaires. Cette enzyme est très fortement exprimée dans les cellules de Leydig fœtales. Elle est également exprimée dans les gonocytes mais plus faiblement et à un niveau variable selon les cellules. En revanche, elle est indétectable dans les cellules de Sertoli.En conclusion, cette étude montre pour la première fois chez la souris que 1) l’aromatase est exprimée dès le début de l’ontogenèse testiculaire, 2) elle est exprimée dans les gonocytes suggérant que ces cellules interviennent dans l’endocrinologie testiculaire et que le rapport oestrogènes/androgènes est plus important dans les gonocytes que dans le liquide interstitiel. En outre, on sait que, chez le fœtus de rat l’aromatase est essentiellement exprimée par les cellules de Sertoli. Nous proposons de prendre en compte cette différence inter-espèces comme un nouveau concept pour comprendre les diff

  1. Inhibition of aromatase activity by flavonoids.

    PubMed

    Jeong, H J; Shin, Y G; Kim, I H; Pezzuto, J M

    1999-06-01

    In searching for potent cancer chemopreventive agents from synthetic or natural products, 28 randomly selected flavonoids were screened for inhibitory effects against partially purified aromatase prepared from human placenta. Over 50% of the flavonoids significantly inhibited aromatase activity, with greatest activity being demonstrated with apigenin (IC50: 0.9 microg/mL), chrysin (IC50: 1.1 microg/mL), and hesperetin (IC50: 1.0 microg/mL).

  2. NEW EXPERIMENTAL MODELS FOR AROMATASE INHIBITOR RESISTANCE

    PubMed Central

    Chen, Shiuan; Masri, Selma; Hong, Yanyan; Wang, Xin; Phung, Sheryl; Yuan, Yate-Ching; Wu, Xiwei

    2009-01-01

    Clinical trials have demonstrated the importance of aromatase inhibitor (AI) therapy in the effective treatment of hormone-dependent breast cancers. In contrast to tamoxifen, an antagonist of the estrogen receptor (ER), AIs have shown to be better tolerated along with decreased recurrence rates of the disease. Currently, three third-generation AIs are being used: exemestane, letrozole and anastrozole. Our laboratory is attempting to understand several aspects of aromatase inhibitor functionality. In this paper, we first review recent findings from our structure-function studies of aromatase as well as the molecular characterization of the interaction between AIs and aromatase. Based on these studies, we propose new evidence for the interaction of letrozole and exemestane with aromatase. In addition, we will discuss recent results generated from our AI-resistant cell lines. Our laboratory has generated MCF-7aro cells that are resistant to letrozole, anastrozole, exemestane and tamoxifen. Basic functional characterization of aromatase and ERα in these resistant cell lines has been done and microarray analysis has been employed in order to better understand the mechanism responsible for AI resistance on a genome-wide scale. The results generated so far suggest the presence of at least four types of resistant cell lines. Overall, the information presented in this paper supplements our understanding of AI function, and such information can be valuable for the development of treatment strategies against AI resistant breast cancers. PMID:17611102

  3. Cytochrome f

    SciTech Connect

    Soriano, G.M.; Smith, J.L.; Cramer, W.A.

    2001-07-17

    Cytochrome f (f, folium, leaf), a c-type cytochrome with a characteristic CysXXCysHis amino acid sequence for heme ligation, is the largest of the four major protein subunits of the membrane-embedded cytochrome b{sub 6}{sup f} complex of oxygenic photosynthesis. It contains 285-86 amino acids, consisting of a soluble 250-residue domain on the p-side (positive-side) or lumen-side of the membrane, a single trans-membrane 20-residue {alpha}-helix, and an n- or stromal-side segment consisting of 15 residues. These domains contain, respectively, the heme prosthetic group and intraprotein electron transfer pathway, the membrane anchor and a short segment that is important in the assembly of the b{sub 6}{sup f} complex. The function of the cytochrome f in oxygenic photosynthesis is to act as the terminal electron acceptor in the membrane-embedded cytochrome b{sub 6}{sup f} complex that provides the electron transport connection between the photosystem II and photosystem I reaction centers. Electron transfer through the complex is coupled to proton translocation and generation of a proton electrochemical potential that is utilized to drive the synthesis of ATP through the proton-motive ATP synthase. These functions of the cytochrome b{sub 6}{sup f} complex are analogous to those of the multisubunit cytochrome bc{sub 1} complex (ubiquinol:cytochrome c oxidoreductase) of the mitochondrial respiratory chain and photosynthetic bacteria. Both complexes contain four redox centers with very similar redox and structural properties: a covalently bound c-type heme in cytochrome f or c{sub 1}, the 2Fe-2S cluster of the Rieske ISP, and the two noncovalently bound hemes of cytochrome b. The structure properties have been defined in 3.0-3.1 {angstrom} structures of the b{sub 6}{sup f} complex from a thermophilic cyanobacterium and a green alga. These structures also defined a fifth redox prosthetic group, a novel covalently bound heme, tentatively called heme x. With the exception of

  4. Molecular basis of the inhibition of human aromatase (estrogen synthetase) by flavone and isoflavone phytoestrogens: A site-directed mutagenesis study.

    PubMed

    Kao, Y C; Zhou, C; Sherman, M; Laughton, C A; Chen, S

    1998-02-01

    Flavone and isoflavone phytoestrogens are plant chemicals and are known to be competitive inhibitors of cytochrome P450 aromatase with respect to the androgen substrate. Aromatase is the enzyme that converts androgen to estrogen; therefore, these plant chemicals are thought to be capable of modifying the estrogen level in women. In this study, the inhibition profiles of four flavones [chrysin (5, 7-dihydroxyflavone), 7,8-dihydroxyflavone, baicalein (5,6,7-trihydroxyflavone), and galangin (3,5,7-trihydroxyflavone)], two isoflavones [genistein (4,5,7-trihydroxyisoflavone) and biochanin A (5,7-dihydroxy-4-methoxyisoflavone)], one flavanone [naringenin (4, 5,7-trihydroxyflavanone)], and one naphthoflavone (alpha-naphthoflavone) on the wild-type and six human aromatase mutants (I133Y, P308F, D309A, T310S, I395F, and I474Y) were determined. In combination with computer modeling, the binding characteristics and the structure requirement for flavone and isoflavone phytoestrogens to inhibit human aromatase were obtained. These compounds were found to bind to the active site of aromatase in an orientation in which rings A and C mimic rings D and C of the androgen substrate, respectively. This study also provides a molecular basis as to why isoflavones are significantly poorer inhibitors of aromatase than flavones.

  5. Molecular basis of the inhibition of human aromatase (estrogen synthetase) by flavone and isoflavone phytoestrogens: A site-directed mutagenesis study.

    PubMed Central

    Kao, Y C; Zhou, C; Sherman, M; Laughton, C A; Chen, S

    1998-01-01

    Flavone and isoflavone phytoestrogens are plant chemicals and are known to be competitive inhibitors of cytochrome P450 aromatase with respect to the androgen substrate. Aromatase is the enzyme that converts androgen to estrogen; therefore, these plant chemicals are thought to be capable of modifying the estrogen level in women. In this study, the inhibition profiles of four flavones [chrysin (5, 7-dihydroxyflavone), 7,8-dihydroxyflavone, baicalein (5,6,7-trihydroxyflavone), and galangin (3,5,7-trihydroxyflavone)], two isoflavones [genistein (4,5,7-trihydroxyisoflavone) and biochanin A (5,7-dihydroxy-4-methoxyisoflavone)], one flavanone [naringenin (4, 5,7-trihydroxyflavanone)], and one naphthoflavone (alpha-naphthoflavone) on the wild-type and six human aromatase mutants (I133Y, P308F, D309A, T310S, I395F, and I474Y) were determined. In combination with computer modeling, the binding characteristics and the structure requirement for flavone and isoflavone phytoestrogens to inhibit human aromatase were obtained. These compounds were found to bind to the active site of aromatase in an orientation in which rings A and C mimic rings D and C of the androgen substrate, respectively. This study also provides a molecular basis as to why isoflavones are significantly poorer inhibitors of aromatase than flavones. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:9435150

  6. Aromatase inhibitors: assessment of biochemical efficacy measured by total body aromatase inhibition and tissue estrogen suppression.

    PubMed

    Lønning, Per E; Geisler, Jürgen

    2008-02-01

    The implementation of aromatase inhibitors for treatment of early and metastatic breast cancer has been one of the major improvements in endocrine therapy of breast cancer. Measurement of endocrine effects of aromatase inhibition in vivo has been a major tool in the process of evaluating novel compounds. Biochemical efficacy of aromatase inhibitors in vivo may be determined from their effects on "total body aromatization" as well changes in plasma and tissue estrogen levels. Due to high sensitivity, tracer methods allowing calculation of whole body aromatase inhibition are still considered the gold standard. The method developed by our group in collaboration with the Royal Marsden Hospital and the results of this joint program are summarized and discussed. These studies allowed classification of the different aromatase inhibitors and their optimal dosage, selecting the best compounds for clinical evaluation. In vivo total body aromatase assessment is a work-consuming method, allowing such studies to be conducted in a limited number of patients only. In contrast, plasma estrogen measurement is a cruder but simpler method, allowing screening of larger groups of patients. As plasma estrogens arise through passive diffusion of estrogens synthesized in different body compartments, plasma estrogens, as well as total body aromatase assessment, present a rough estimate of total body tissue estrogen production, and changes associated with treatment with aromatase inhibitors reflect the effects on tissue estrogen production in general. However, plasma estrogen levels do not correlate to breast cancer tissue estrogen levels. This is due to the endocrine autonomy of breast cancer tissue with significant local estrogen production in some tumors. Thus, direct measurement of intratumor estrogens is demanded to evaluate the effects of aromatase inhibitors in malignant target tissues. Our group has developed a highly sensitive HPLC-RIA for the simultaneous measurement of estrone

  7. In vivo visualization of aromatase in animals and humans

    PubMed Central

    Biegon, Anat

    2015-01-01

    Aromatase catalyzes the last and obligatory step in the biosynthesis of estrogens across species. In vivo visualization of aromatase can be performed using positron emission tomography (PET) with radiolabeled aromatase inhibitors such as [11C]vorozole. PET studies in rats, monkeys and healthy human subjects demonstrate widespread but heterogeneous aromatase availability in brain and body, which appears to be regulated in a species, sex and region-specific manner. Thus, aromatase availability is high in brain amygdala and in ovaries of all species examined to date, with males demonstrating higher levels than females in all comparable organs. However, the highest concentrations of aromatase in the human brain are found in specific nuclei of the thalamus while the highest levels in rats and monkeys are found in the amygdala. Regional brain aromatase availability is increased by androgens and inhibited by nicotine. Future studies may improve diagnosis and treatment in brain disorders and cancers overexpressing aromatase. PMID:26456904

  8. Placental sulfatase deficiency: clinical and biochemical study of 16 cases.

    PubMed

    Bedin, M; Alsat, E; Tanguy, G; Cedard, L

    1980-01-01

    Clinical and biochemical data of 16 typical cases of placental sulfatase deficiency have been observed. In vivo loading tests with DHA-S allowed us to make a prenatal diagnosis. In vitro experiments gave confirmation, showing zero or virtually zero placental sulfatase activity towards delta 5P or DHA sulfates Aromatase activities, when tested, were normal or more often less than standard values, the latter showing themselves rather large individual variations. All pregnancies were associated with the delivery of male neonates in good health but 3. The 15 living babies have been developing normally since then. These results, together with those reported in the literature, suggest that placental sulfatase deficiency is under control of an X-linked recessive character, this being supported by the recent observation of such a disorder in two sisters simultaneously pregnant. As to the high frequency problem of cesarian section, pointed out by several authors, we cannot conclude, from our own observations, that the defect has an obvious influence on the good outcome of labor, as 10 out of the 16 women delivered vaginally near term.

  9. Combination Effects of (Tri)Azole Fungicides on Hormone Production and Xenobiotic Metabolism in a Human Placental Cell Line

    PubMed Central

    Rieke, Svenja; Koehn, Sophie; Hirsch-Ernst, Karen; Pfeil, Rudolf; Kneuer, Carsten; Marx-Stoelting, Philip

    2014-01-01

    Consumers are exposed to multiple residues of different pesticides via the diet. Therefore, EU legislation for pesticides requires the evaluation of single active substances as well as the consideration of combination effects. Hence the analysis of combined effects of substances in a broad dose range represents a key challenge to current experimental and regulatory toxicology. Here we report evidence for additive effects for (tri)azole fungicides, a widely used group of antifungal agents, in the human placental cell line Jeg-3. In addition to the triazoles cyproconazole, epoxiconazole, flusilazole and tebuconazole and the azole fungicide prochloraz also pesticides from other chemical classes assumed to act via different modes of action (i.e., the organophosphate chlorpyrifos and the triazinylsulfonylurea herbicide triflusulfuron-methyl) were investigated. Endpoints analysed include synthesis of steroid hormone production (progesterone and estradiol) and gene expression of steroidogenic and non-steroidogenic cytochrome-P-450 (CYP) enzymes. For the triazoles and prochloraz, a dose dependent inhibition of progesterone production was observed and additive effects could be confirmed for several combinations of these substances in vitro. The non-triazoles chlorpyrifos and triflusulfuron-methyl did not affect this endpoint and, in line with this finding, no additivity was observed when these substances were applied in mixtures with prochloraz. While prochloraz slightly increased aromatase expression and estradiol production and triflusulfuron-methyl decreased estradiol production, none of the other substances had effects on the expression levels of steroidogenic CYP-enzymes in Jeg-3 cells. For some triazoles, prochloraz and chlorpyrifos a significant induction of CYP1A1 mRNA expression and potential combination effects for this endpoint were observed. Inhibition of CYP1A1 mRNA induction by the AhR inhibitor CH223191 indicated AhR receptor dependence of this effect. PMID

  10. Combination effects of (tri)azole fungicides on hormone production and xenobiotic metabolism in a human placental cell line.

    PubMed

    Rieke, Svenja; Koehn, Sophie; Hirsch-Ernst, Karen; Pfeil, Rudolf; Kneuer, Carsten; Marx-Stoelting, Philip

    2014-09-17

    Consumers are exposed to multiple residues of different pesticides via the diet. Therefore, EU legislation for pesticides requires the evaluation of single active substances as well as the consideration of combination effects. Hence the analysis of combined effects of substances in a broad dose range represents a key challenge to current experimental and regulatory toxicology. Here we report evidence for additive effects for (tri)azole fungicides, a widely used group of antifungal agents, in the human placental cell line Jeg-3. In addition to the triazoles cyproconazole, epoxiconazole, flusilazole and tebuconazole and the azole fungicide prochloraz also pesticides from other chemical classes assumed to act via different modes of action (i.e., the organophosphate chlorpyrifos and the triazinylsulfonylurea herbicide triflusulfuron-methyl) were investigated. Endpoints analysed include synthesis of steroid hormone production (progesterone and estradiol) and gene expression of steroidogenic and non-steroidogenic cytochrome-P-450 (CYP) enzymes. For the triazoles and prochloraz, a dose dependent inhibition of progesterone production was observed and additive effects could be confirmed for several combinations of these substances in vitro. The non-triazoles chlorpyrifos and triflusulfuron-methyl did not affect this endpoint and, in line with this finding, no additivity was observed when these substances were applied in mixtures with prochloraz. While prochloraz slightly increased aromatase expression and estradiol production and triflusulfuron-methyl decreased estradiol production, none of the other substances had effects on the expression levels of steroidogenic CYP-enzymes in Jeg-3 cells. For some triazoles, prochloraz and chlorpyrifos a significant induction of CYP1A1 mRNA expression and potential combination effects for this endpoint were observed. Inhibition of CYP1A1 mRNA induction by the AhR inhibitor CH223191 indicated AhR receptor dependence this effect.

  11. Pharmacophore modeling and in silico screening for new P450 19 (aromatase) inhibitors.

    PubMed

    Schuster, Daniela; Laggner, Christian; Steindl, Theodora M; Palusczak, Anja; Hartmann, Rolf W; Langer, Thierry

    2006-01-01

    Cytochrome P450 19 (P450 19, aromatase) constitutes a successful target for the treatment of breast cancer. This study analyzes chemical features common to P450 19 inhibitors to develop ligand-based, selective pharmacophore models for this enzyme. The HipHop and HypoRefine algorithms implemented in the Catalyst software package were employed to create both common feature and quantitative models. The common feature model for P450 19 includes two ring aromatic features in its core and two hydrogen bond acceptors at the ends. The models were used as database search queries to identify active compounds from the NCI database.

  12. Aromatase and leiomyoma of the uterus.

    PubMed

    Shozu, Makio; Murakami, Kouich; Inoue, Masaki

    2004-02-01

    In leiomyoma of the uterus, both aromatase and 17beta-hydroxysteroid dehydrogenase (17beta-HSD) type I are overexpressed compared with myometrium. This suggests that leiomyoma cells convert circulating androstenedione into estrone (via aromatase), then into the active form of estrogen, estradiol (via 17beta-HSD type I). In vitro experiments and several clinical findings support the notion that in situ estrogen plays a role in leiomyoma growth under hypoestrogenemic conditions, such as natural menopause and therapy with gonadotropin-releasing hormone (GnRH) agonists. GnRH agonists abolish estrogen production both in situ in leiomyoma and in the ovary, leading to quick and profound regression of the leiomyoma. Aromatase inhibitors also inhibit estrogen synthesis in both leiomyoma and the ovary and may be used therapeutically. Certain doses of competitive aromatase inhibitors would completely inhibit estrogen production in leiomyoma, whereas ovarian production of estrogen would continue at reduced levels. This may lead to advantageous therapeutic conditions in which leiomyoma regresses without adverse symptoms related to estrogen depletion because levels of ovarian estrogen would be insufficient to support leiomyoma growth but sufficient to prevent symptoms associated with deficiency. This article discusses the potential uses of aromatase inhibitors.

  13. QSAR modeling of aromatase inhibitory activity of 1-substituted 1,2,3-triazole analogs of letrozole.

    PubMed

    Nantasenamat, Chanin; Worachartcheewan, Apilak; Prachayasittikul, Supaluk; Isarankura-Na-Ayudhya, Chartchalerm; Prachayasittikul, Virapong

    2013-11-01

    Aromatase is an estrogen biosynthesis enzyme belonging to the cytochrome P450 family that catalyzes the rate-limiting step of converting androgens to estrogens. As it is pertinent toward tumor cell growth promotion, aromatase is a lucrative therapeutic target for breast cancer. In the pursuit of robust aromatase inhibitors, a set of fifty-four 1-substituted mono- and bis-benzonitrile or phenyl analogs of 1,2,3-triazole letrozole were employed in quantitative structure-activity relationship (QSAR) study using multiple linear regression (MLR), artificial neural network (ANN) and support vector machine (SVM). Such QSAR models were developed using a set of descriptors providing coverage of the general characteristics of a molecule encompassing molecular size, flexibility, polarity, solubility, charge and electronic properties. Important physicochemical properties giving rise to good aromatase inhibition were obtained by means of exploring its chemical space as a function of the calculated molecular descriptors. The optimal subset of 3 descriptors (i.e. number of rings, ALogP and HOMO-LUMO) was further used for QSAR model construction. The predicted pIC₅₀ values were in strong correlation with their experimental values displaying correlation coefficient values in the range of 0.72-0.83 for the cross-validated set (QCV) while the external test set (Q(Ext)) afforded values in the range of 0.65-0.66. Insights gained from the present study are anticipated to provide pertinent information contributing to the origins of aromatase inhibitory activity and therefore aid in our on-going quest for aromatase inhibitors with robust properties.

  14. Disruption of aromatase homeostasis as the cause of a multiplicity of ailments: A comprehensive review.

    PubMed

    Patel, Seema

    2017-04-01

    Human health is beset with a legion of ailments, which is exacerbated by lifestyle errors. Out of the numerous enzymes in human body, aromatase, a cytochrome P450 enzyme is particularly very critical. Occurring at the crossroads of multiple signalling pathways, its homeostasis is vital for optimal health. Unfortunately, medications, hormone therapy, chemical additives in food, and endocrine-disrupting personal care products are oscillating the aromatase concentration beyond the permissible level. As this enzyme converts androgens (C19) into estrogens (C18), its agitation has different outcomes in different genders and age groups. Some common pathologies associated with aromatase disruption include breast cancer, prostate cancer, polycystic ovary syndrome (PCOS), endometriosis, osteoporosis, ovarian cancer, gastric cancer, pituitary cancer, Alzheimer's disease, schizophrenia, male hypogonadism, and transgender issues. Several drugs, cosmetics and pesticides act as the activators and suppressors of this enzyme. This carefully-compiled critical review is expected to increase public awareness regarding the threats resultant of the perturbations of this enzyme and to motivate researchers for further investigation of this field.

  15. Study of substrate specificity of human aromatase by site directed mutagenesis.

    PubMed

    Auvray, P; Nativelle, C; Bureau, R; Dallemagne, P; Séralini, G-E; Sourdaine, P

    2002-03-01

    Human aromatase is responsible for estrogen biosynthesis and is implicated, in particular, in reproduction and estrogen-dependent tumor proliferation. The molecular structure model is largely derived from the X-ray structure of bacterial cytochromes sharing only 15-20% identities with hP-450arom. In the present study, site directed mutagenesis experiments were performed to examine the role of K119, C124, I125, K130, E302, F320, D309, H475, D476, S470, I471 and I474 of aromatase in catalysis and for substrate binding. The catalytic properties of mutants, transfected in 293 cells, were evaluated using androstenedione, testosterone or nor-testosterone as substrates. In addition, inhibition profiles for these mutants with indane or indolizinone derivatives were obtained. Our results, together with computer modeling, show that catalytic properties of mutants vary in accordance with the substrate used, suggesting possible differences in substrates positioning within the active site. In this respect, importance of residues H475, D476 and K130 was discussed. These results allow us to hypothesize that E302 could be involved in the aromatization mechanism with nor-androgens, whereas D309 remains involved in androgen aromatization. This study highlights the flexibility of the substrate-enzyme complex conformation, and thus sheds new light on residues that may be responsible for substrate specificity between species or aromatase isoforms.

  16. New aromatase inhibitors. Synthesis and biological activity of pyridyl-substituted tetralone derivatives.

    PubMed

    Bayer, H; Batzl, C; Hartmann, R W; Mannschreck, A

    1991-09-01

    The (E)-2-(4-pyridylmethylene)-1-tetralones 1-7 (1, H; 2, 5-OCH3; 3, 6-OCH3; 4, 7-OCH3; 5, 5-OH; 6, 6-OH; 7, 7-OH) were obtained by aldol condensation of the corresponding 1-tetralones with 4-pyridinecarboxaldehyde, and in the case of the OH compounds 5 and 7 subsequent ether cleavage of the OCH3-substituted 2-(4-pyridylmethylene)-1-tetralones. Catalytic hydrogenation of 1-4 gave the 2-(4-pyridylmethyl)-1-tetralones 8-11 (8, H; 9, 5-OCH3; 10, 6-OCH3; 11, 7-OCH3). Subsequent ether cleavage of 9-11 led to the corresponding OH compounds 12-14 (12, 5-OH; 13, 6-OH; 14, 7-OH). The enantiomers of 11 and 12 were separated semipreparatively by HPLC on triacetylcellulose. All compounds (1-14) showed an inhibition of human placental aromatase exhibiting relative potencies from 2.2 to 213 [compounds 6 and (+)-12, respectively; aromatase inhibitory potency of aminoglutethimide (AG) = 1]. The compounds exhibited no or only a weak inhibition of desmolase [cholesterol side chain cleavage enzyme; maximum activity shown by 12, 23% inhibition (25 microM); AG, 53% inhibition (25 microM)]. In vivo, however, the compounds were not superior to AG as far as the reduction of the plasma estradiol concentration and the mammary carcinoma (MC) inhibiting properties are concerned (PMSG-primed SD rats as well as DMBA-induced MC of the SD rat, pre- and postmenopausal experiments, and the transplantable MXT-MC of the BD2F1 mouse). This is due to a fast decrease of the plasma E2 concentration inhibiting effect as could be shown by a kinetic experiment. In addition, select compounds inhibited rat ovarian aromatase much less than human placental aromatase (12, factor of 10). Estrogenic effects as a cause for the poor in vivo activity of the test compounds could be excluded, since they did not show affinity for the estrogen receptor.

  17. Natural compounds with aromatase inhibitory activity: an update.

    PubMed

    Balunas, Marcy J; Kinghorn, A Douglas

    2010-08-01

    Several synthetic aromatase inhibitors are currently in clinical use for the treatment of postmenopausal women with hormone-receptor positive breast cancer. However, these treatments may lead to untoward side effects and so the search for new aromatase inhibitors continues, especially those for which the activity is promoter-specific, targeting the breast-specific promoters I.3 and II. Recently, numerous natural compounds have been found to inhibit aromatase in noncellular, cellular, and IN VIVO studies. These investigations, covering the last two years, as well as additional studies that have focused on the evaluation of natural compounds as promoter-specific aromatase inhibitors or as aromatase inducers, are described in this review.

  18. Placental Permeability of Lead

    PubMed Central

    Carpenter, Stanley J.

    1974-01-01

    The detection of lead in fetal tissues by chemical analysis has long been accepted as prima facie evidence for the permeability of the placenta to this nonessential trace metal. However, only a few investigations, all on lower mammalian species, have contributed any direct experimental data bearing on this physiological process. Recent radioactive tracer and radioautographic studies on rodents have shown that lead crosses the placental membranes rapidly and in significant amounts even at relatively low maternal blood levels. While it is not possible to extrapolate directly the results of these experiments to humans because of differences in placental structure and other factors, the results do serve as a warning of the possible hazard to the human embryo and fetus of even low levels of lead in the maternal system. PMID:4857497

  19. Inhibition of human aromatase by myosmine.

    PubMed

    Doering, Irene L; Richter, Elmar

    2009-04-01

    Myosmine, a minor tobacco alkaloid widely occurring in food products of plant and animal origin, inhibits the conversion of testosterone to estradiol by human aromatase (IC(50): 33+/-2 microM) sevenfold more potent than nicotine (IC(50): 223+/-10 microM) and may have implications for sexual hormone homoeostasis.

  20. Effects of chloro-s-triazine herbicides and metabolites on aromatase activity in various human cell lines and on vitellogenin production in male carp hepatocytes.

    PubMed Central

    Sanderson, J T; Letcher, R J; Heneweer, M; Giesy, J P; van den Berg, M

    2001-01-01

    We investigated a potential mechanism for the estrogenic properties of three chloro-s-triazine herbicides and six metabolites in vitro in several cell systems. We determined effects on human aromatase (CYP19), the enzyme that converts androgens to estrogens, in H295R (adrenocortical carcinoma), JEG-3 (placental choriocarcinoma), and MCF-7 (breast cancer) cells; we determined effects on estrogen receptor-mediated induction of vitellogenin in primary hepatocyte cultures of adult male carp (Cyprinus carpio). In addition to atrazine, simazine, and propazine, two metabolites--atrazine-desethyl and atrazine-desisopropyl--induced aromatase activity in H295R cells concentration-dependently (0.3-30 microM) and with potencies similar to those of the parent triazines. After a 24-hr exposure to 30 microM of the triazines, an apparent maximum induction of about 2- to 2.5-fold was achieved. The induction responses were confirmed by similar increases in CYP19 mRNA levels, determined by reverse-transcriptase polymerase chain reaction. In JEG-3 cells, where basal aromatase expression is about 15-fold greater than in H295R cells, the induction responses were similar but less pronounced; aromatase expression in MCF-7 cells was neither detectable nor inducible under our culture conditions. The fully dealkylated metabolite atrazine-desethyl-desisopropyl and the three hydroxylated metabolites (2-OH-atrazine-desethyl, -desisopropyl, and -desethyl-desisopropyl) did not induce aromatase activity. None of the triazine herbicides nor their metabolites induced vitellogenin production in male carp hepatocytes; nor did they antagonize the induction of vitellogenin by 100 nM (EC(50) 17beta-estradiol. These findings together with other reports indicate that the estrogenic effects associated with the triazine herbicides in vivo are not estrogen receptor-mediated, but may be explained partly by their ability to induce aromatase in vitro. PMID:11675267

  1. Effects of currently used pesticides in assays for estrogenicity, androgenicity, and aromatase activity in vitro.

    PubMed

    Andersen, Helle Raun; Vinggaard, Anne Marie; Rasmussen, Thomas Hoj; Gjermandsen, Irene Marianne; Bonefeld-Jørgensen, Eva Cecilie

    2002-02-15

    Twenty-four pesticides were tested for interactions with the estrogen receptor (ER) and the androgen receptor (AR) in transactivation assays. Estrogen-like effects on MCF-7 cell proliferation and effects on CYP19 aromatase activity in human placental microsomes were also investigated. Pesticides (endosulfan, methiocarb, methomyl, pirimicarb, propamocarb, deltamethrin, fenpropathrin, dimethoate, chlorpyriphos, dichlorvos, tolchlofos-methyl, vinclozolin, iprodion, fenarimol, prochloraz, fosetyl-aluminum, chlorothalonil, daminozid, paclobutrazol, chlormequat chlorid, and ethephon) were selected according to their frequent use in Danish greenhouses. In addition, the metabolite mercaptodimethur sulfoxide, the herbicide tribenuron-methyl, and the organochlorine dieldrin, were included. Several of the pesticides, dieldrin, endosulfan, methiocarb, and fenarimol, acted both as estrogen agonists and androgen antagonists. Prochloraz reacted as both an estrogen and an androgen antagonist. Furthermore, fenarimol and prochloraz were potent aromatase inhibitors while endosulfan was a weak inhibitor. Hence, these three pesticides possess at least three different ways to potentially disturb sex hormone actions. In addition, chlorpyrifos, deltamethrin, tolclofos-methyl, and tribenuron-methyl induced weak responses in one or both estrogenicity assays. Upon cotreatment with 17beta-estradiol, the response was potentiated by endosulfan in the proliferation assay and by pirimicarb, propamocarb, and daminozid in the ER transactivation assay. Vinclozolin reacted as a potent AR antagonist and dichlorvos as a very weak one. Methomyl, pirimicarb, propamocarb, and iprodion weakly stimulated aromatase activity. Although the potencies of the pesticides to react as hormone agonists or antagonists are low compared to the natural ligands, the integrated response in the organism might be amplified by the ability of the pesticides to act via several mechanism and the frequent simultaneous exposure to

  2. Methadone: a substrate and mechanism-based inhibitor of CYP19 (aromatase).

    PubMed

    Lu, Wenjie Jessie; Bies, Robert; Kamden, Landry K; Desta, Zeruesenay; Flockhart, David A

    2010-08-01

    The peripheral conversion of testosterone to estradiol by aromatase is the primary source of endogenous estrogen in postmenopausal women. Studies indicating that placental aromatase is able to metabolize methadone to its primary metabolite, 2-ethylidene-1, 5-dimethyl-3, 3-diphenylpyrrolidin (EDDP), led us to test the hypothesis that methadone is able to act as an inhibitor of aromatase. Using recombinant human CYP19, we examined the ability of methadone to bring about either reversible or mechanism-based inhibition of the conversion of testosterone to estradiol. To test for reversible inhibition, racemic methadone or its metabolite EDDP or 2-ethyl-5-methyl-3, 3-diphenylpyrroline (EMDP) was incubated for 30 min with testosterone at the K(m) (4 microM). To test for mechanism-based inhibition, microsomal preincubations were performed for up to 30 min using racemic methadone (1-1000 microM), R- or S-methadone (0.5-500 microM), or EDDP or EMDP (10 and 100 microM) followed by incubation with testosterone at a V(max) concentration (50 microM). Racemic methadone, EDDP, and EMDP did not act as competitive inhibitors of CYP19. Preincubation of methadone, EDDP, or EMDP with CYP19 resulted in time- and concentration-dependent inhibition, indicating a mechanism-based reaction that destroys CYP19 activity. The K(I) and k(inact) values for racemic methadone were calculated to be 40.6 +/- 2.8 microM and 0.061 +/- 0.001 min(-1), respectively. No stereoselectivity was observed. Methadone is metabolized by CYP19 and may act as a potent inhibitor of CYP19 in vivo. These findings may contribute to variability in methadone clearance, to drug-drug interactions, and to side effects observed in individual patients.

  3. Aromatase inhibiting and combined estrogenic effects of parabens and estrogenic effects of other additives in cosmetics

    SciTech Connect

    Meeuwen, J.A. van Son, O. van; Piersma, A.H.; Jong, P.C. de; Berg, M. van den

    2008-08-01

    There is concern widely on the increase in human exposure to exogenous (anti)estrogenic compounds. Typical are certain ingredients in cosmetic consumer products such as musks, phthalates and parabens. Monitoring a variety of human samples revealed that these ingredients, including the ones that generally are considered to undergo rapid metabolism, are present at low levels. In this in vitro research individual compounds and combinations of parabens and endogenous estradiol (E{sub 2}) were investigated in the MCF-7 cell proliferation assay. The experimental design applied a concentration addition model (CA). Data were analyzed with the estrogen equivalency (EEQ) and method of isoboles approach. In addition, the catalytic inhibitory properties of parabens on an enzyme involved in a rate limiting step in steroid genesis (aromatase) were studied in human placental microsomes. Our results point to an additive estrogenic effect in a CA model for parabens. In addition, it was found that parabens inhibit aromatase. Noticeably, the effective levels in both our in vitro systems were far higher than the levels detected in human samples. However, estrogenic compounds may contribute in a cumulative way to the circulating estrogen burden. Our calculation for the extra estrogen burden due to exposure to parabens, phthalates and polycyclic musks indicates an insignificant estrogenic load relative to the endogenous or therapeutic estrogen burden.

  4. Placental steroids in cattle: hormones, placental growth factors or by-products of trophoblast giant cell differentiation?

    PubMed

    Schuler, G; Greven, H; Kowalewski, M P; Döring, B; Ozalp, G R; Hoffmann, B

    2008-07-01

    The bovine placenta produces large amounts of steroids, mainly estrone (E1) and progesterone (P4). Specific features of bovine placental steroidogenesis are 1) the expression of all enzymes needed for the production of estrogens from cholesterol in the trophoblast 2) an only marginal and temporal contribution to peripheral maternal P4 levels restricted to a period between approx. days 150 - 240 of gestation 3) the predominance of sulfoconjugated over free E1 and 4) a complementary setting of steroidogenic enzymes in the two morphologically discriminable trophoblast cell types, the uninucleated trophoblast cells (UTC) and the trophoblast giant cells (TGC). In cattle so far no definite information is available on the specific biological roles of placental estrogens and P4. However, the detection of estrogen receptors and progesterone receptors in the placentomes suggests a role primarily as local regulators of caruncular growth, differentiation and functions. Inconsistent with a function as a caruncular growth factor is the strong evidence that in cattle placental estrogens enter the maternal compartment almost completely as estrone sulfate (E1S), which is not active at classical nuclear receptors. On the other hand, E1S may be converted locally to free active estrogens via the action of steroid sulfatase (StS), which has been detected in specific parts of the bovine caruncular epithelium. Alternatively or in addition, StS expression in the caruncular epithelium may serve the utilization of sulfated neutral steroid precursors (e.g. pregnenolone sulfate or cholesterol sulfate) supplied with maternal blood, thus providing free substrates for further metabolization in the adjacent trophoblast. The down-regulation of P450scc and P450c17 and the up-regulation of 3beta-HSD and aromatase during the differentiation of TGC from UTC in parallel with the up-regulation of ER beta and estrogen sulfotransferase in maturing TGC suggests a function of placental estrogens primarily

  5. Paternal Retrieval Behavior Regulated by Brain Estrogen Synthetase (Aromatase) in Mouse Sires that Engage in Communicative Interactions with Pairmates.

    PubMed

    Akther, Shirin; Huang, Zhiqi; Liang, Mingkun; Zhong, Jing; Fakhrul, Azam A K M; Yuhi, Teruko; Lopatina, Olga; Salmina, Alla B; Yokoyama, Shigeru; Higashida, Chiharu; Tsuji, Takahiro; Matsuo, Mie; Higashida, Haruhiro

    2015-01-01

    Parental behaviors involve complex social recognition and memory processes and interactive behavior with children that can greatly facilitate healthy human family life. Fathers play a substantial role in child care in a small but significant number of mammals, including humans. However, the brain mechanism that controls male parental behavior is much less understood than that controlling female parental behavior. Fathers of non-monogamous laboratory ICR mice are an interesting model for examining the factors that influence paternal responsiveness because sires can exhibit maternal-like parental care (retrieval of pups) when separated from their pups along with their pairmates because of olfactory and auditory signals from the dams. Here we tested whether paternal behavior is related to femininity by the aromatization of testosterone. For this purpose, we measured the immunoreactivity of aromatase [cytochrome P450 family 19 (CYP19)], which synthesizes estrogen from androgen, in nine brain regions of the sire. We observed higher levels of aromatase expression in these areas of the sire brain when they engaged in communicative interactions with dams in separate cages. Interestingly, the number of nuclei with aromatase immunoreactivity in sires left together with maternal mates in the home cage after pup-removing was significantly larger than that in sires housed with a whole family. The capacity of sires to retrieve pups was increased following a period of 5 days spent with the pups as a whole family after parturition, whereas the acquisition of this ability was suppressed in sires treated daily with an aromatase inhibitor. The results demonstrate that the dam significantly stimulates aromatase in the male brain and that the presence of the pups has an inhibitory effect on this increase. These results also suggest that brain aromatization regulates the initiation, development, and maintenance of paternal behavior in the ICR male mice.

  6. Paternal Retrieval Behavior Regulated by Brain Estrogen Synthetase (Aromatase) in Mouse Sires that Engage in Communicative Interactions with Pairmates

    PubMed Central

    Akther, Shirin; Huang, Zhiqi; Liang, Mingkun; Zhong, Jing; Fakhrul, Azam A. K. M.; Yuhi, Teruko; Lopatina, Olga; Salmina, Alla B.; Yokoyama, Shigeru; Higashida, Chiharu; Tsuji, Takahiro; Matsuo, Mie; Higashida, Haruhiro

    2015-01-01

    Parental behaviors involve complex social recognition and memory processes and interactive behavior with children that can greatly facilitate healthy human family life. Fathers play a substantial role in child care in a small but significant number of mammals, including humans. However, the brain mechanism that controls male parental behavior is much less understood than that controlling female parental behavior. Fathers of non-monogamous laboratory ICR mice are an interesting model for examining the factors that influence paternal responsiveness because sires can exhibit maternal-like parental care (retrieval of pups) when separated from their pups along with their pairmates because of olfactory and auditory signals from the dams. Here we tested whether paternal behavior is related to femininity by the aromatization of testosterone. For this purpose, we measured the immunoreactivity of aromatase [cytochrome P450 family 19 (CYP19)], which synthesizes estrogen from androgen, in nine brain regions of the sire. We observed higher levels of aromatase expression in these areas of the sire brain when they engaged in communicative interactions with dams in separate cages. Interestingly, the number of nuclei with aromatase immunoreactivity in sires left together with maternal mates in the home cage after pup-removing was significantly larger than that in sires housed with a whole family. The capacity of sires to retrieve pups was increased following a period of 5 days spent with the pups as a whole family after parturition, whereas the acquisition of this ability was suppressed in sires treated daily with an aromatase inhibitor. The results demonstrate that the dam significantly stimulates aromatase in the male brain and that the presence of the pups has an inhibitory effect on this increase. These results also suggest that brain aromatization regulates the initiation, development, and maintenance of paternal behavior in the ICR male mice. PMID:26696812

  7. Malignant cancer and invasive placentation

    PubMed Central

    D'Souza, Alaric W.; Wagner, Günter P.

    2014-01-01

    Cancer metastasis is an invasive process that involves the transplantation of cells into new environments. Since human placentation is also invasive, hypotheses about a relationship between invasive placentation in eutherian mammals and metastasis have been proposed. The relationship between metastatic cancer and invasive placentation is usually presented in terms of antagonistic pleiotropy. According to this hypothesis, evolution of invasive placentation also established the mechanisms for cancer metastasis. Here, in contrast, we argue that the secondary evolution of less invasive placentation in some mammalian lineages may have resulted in positive pleiotropic effects on cancer survival by lowering malignancy rates. These positive pleiotropic effects would manifest themselves as resistance to cancer cell invasion. To provide a preliminary test of this proposal, we re-analyze data from Priester and Mantel (Occurrence of tumors in domestic animals. Data from 12 United States and Canadian colleges of veterinary medicine. J Natl Cancer Inst 1971;47:1333-44) about malignancy rates in cows, horses, cats and dogs. From our analysis we found that equines and bovines, animals with less invasive placentation, have lower rates of metastatic cancer than felines and canines in skin and glandular epithelial cancers as well as connective tissue sarcomas. We conclude that a link between type of placentation and species-specific malignancy rates is more likely related to derived mechanisms that suppress invasion rather than different degrees of fetal placental aggressiveness. PMID:25324490

  8. Lead optimization of 4-imidazolylflavans: new promising aromatase inhibitors.

    PubMed

    Yahiaoui, Samir; Pouget, Christelle; Buxeraud, Jacques; Chulia, Albert José; Fagnère, Catherine

    2011-06-01

    Our previous studies have shown that several 7-substituted-4-imidazolylflavans are potent inhibitors of aromatase. These compounds were designed considering the anti-aromatase effect of some natural flavonoids and the importance of an azole ring for synthetic inhibitors such as letrozole or anastrozole towards binding to the heme iron of aromatase. In this study, we report the optimization of these lead compounds by the modulation of flavan A ring. The resulting 7,8-benzo-4-imidazolylflavans were tested in order to assess their ability to inhibit aromatase. Biological data concerning enantiomers obtained from the chiral separation of the racemate compound 4-imidazolyl-7-methoxyflavan are also presented.

  9. Synthesis and PET studies of [11C-cyano]letrozole (Femara), an aromatase inhibitor drug

    SciTech Connect

    kil K. E.; Biegon A.; Kil, K.-E.; Biegon, A.; Ding, Y.-S.; Fischer, A.; Ferrieri, R.A.; Kim, S.-W.; Pareto, D.; Schueller, M.J.; Fowler, J.S.

    2008-11-10

    Aromatase, a member of the cytochrome P450 family, converts androgens such as androstenedione and testosterone to estrone and estradiol respectively. Letrozole (1-[bis-(4-cyanophenyl)methyl]-1H-1,2,4-triazole, Femara{reg_sign}) is a high affinity aromatase inhibitor (K{sub i}=11.5 nM) which has FDA approval for breast cancer treatment. Here we report the synthesis of carbon-11 labeled letrozole and its assessment as a radiotracer for brain aromatase in the baboon. Letrozole and its precursor (4-[(4-bromophenyl)-1H-1,2,4-triazol-1-ylmethyl]benzonitrile, 3) were prepared in two-step syntheses from 4-cyanobenzyl bromide and 4-bromobenzyl bromide, respectively. The [{sup 11}C]cyano group was introduced via the tetrakis(triphenylphosphine)palladium(0) catalyzed coupling of [{sup 11}C]cyanide with the bromo-precursor (3). PET studies in the baboon brain were carried out to assess regional distribution and kinetics, reproducibility of repeated measures and saturability. The free fraction of letrozole in the plasma, log D, and the [{sup 11}C-cyano]letrozole fraction in the arterial plasma were also measured. [{sup 11}C-cyano]Letrozole was synthesized in 60 min with a radiochemical yield of 79-80%, with a radiochemical purity greater than 98% and a specific activity of 4.16 {+-} 2.21 Ci/{micro}mol at the end of bombardment (n=4). PET studies in the baboon revealed initial rapid and high uptake and initial rapid clearance followed by slow clearance of carbon-11 from the brain with no difference between brain regions. The brain kinetics was not affected by co-injection of unlabeled letrozole (0.1 mg/kg). The free fraction of letrozole in plasma was 48.9% and log D was 1.84. [{sup 11}C-cyano]Letrozole is readily synthesized via a palladium catalyzed coupling reaction with [{sup 11}C]cyanide. Although it is unsuitable as a PET radiotracer for brain aromatase as revealed by the absence of regional specificity and saturability in brain regions, such as amygdala, which are known

  10. Aromatase inhibition by bioavailable methylated flavones.

    PubMed

    Ta, Nga; Walle, Thomas

    2007-10-01

    Previous studies have shown chrysin, 7-hydroxyflavone and 7,4'-dihydroxyflavone to be the most potent flavonoid inhibitors of aromatase. However, very poor oral bioavailability is a major limitation for the successful use of dietary flavonoids as chemopreventive agents. We have recently shown that methylated flavones, including 5,7-dimethoxyflavone, 7-methoxyflavone and 7,4'-dimethoxyflavone, are much more resistant to metabolism than their unmethylated analogs and have much higher intestinal absorption. In this study, we examined these fully methylated flavones as potential aromatase inhibitors for the prevention and/or treatment of hormone-dependent cancers. Whereas 5,7-dimethoxyflavone had poor effect compared to its unmethylated analog chrysin, 7-methoxyflavone and 7,4'-dimethoxyflavone were almost equipotent to their unmethylated analogs with IC(50) values of 2-9 microM. Thus, some fully methylated flavones appear to have great potential as cancer chemopreventive/chemotherapeutic agents.

  11. Aromatase inhibition by bioavailable methylated flavones

    PubMed Central

    Ta, Nga; Walle, Thomas

    2007-01-01

    Previous studies have shown chrysin, 7-hydroxyflavone and 7,4′-dihydroxyflavone to be the most potent flavonoid inhibitors of aromatase. However, very poor oral bioavailability is a major limitation for the successful use of dietary flavonoids as chemopreventive agents. We have recently shown that methylated flavones, including 5,7-dimethoxyflavone, 7-methoxyflavone and 7,4′-dimethoxyflavone, are much more resistant to metabolism than their unmethylated analogs and have much higher intestinal absorption. In this study, we examined these fully methylated flavones as potential aromatase inhibitors for the prevention and/or treatment of hormone-dependent cancers. Whereas 5,7-dimethoxyflavone had poor effect compared to its unmethylated analog chrysin, 7-methoxyflavone and 7,4′-dimethoxyflavone were almost equipotent to their unmethylated analogs with IC50 values of 2 to 9 μM. Thus, some fully methylated flavones appear to have great potential as cancer chemopreventive/chemotherapeutic agents. PMID:17624765

  12. The effect of the aromatase inhibitor, 4-(phenylthio)-4-androstene-3,17-dione, on dimethylbenz(A)anthracene-induced rat mammary tumors.

    PubMed

    Abul-Hajj, Y J

    1989-01-01

    4-(Phenylthio)-4-androstene-3,17-dione (4-PTAD), a known inhibitor of human placental aromatase, was examined as a growth inhibitor of DMBA-induced rat mammary tumors. Subcutaneous administration of 4-PTAD at dose levels of 25 or 50 mg/kg/day caused a significant decrease in hormone-dependent tumor growth. Resumption of tumor growth occurred when either the administration of inhibitor was stopped or when inhibitor was coadministered with estradiol indicating that suppression of tumor growth was due to inhibition of estrogen biosynthesis. Additionally, plasma levels of estradiol were found to be lower in the animals treated with 4-PTAD. The major metabolite of 4-PTAD in vitro was identified as 4-(phenylthio)-4-androstene-17 beta-ol-3-one and was found to have 60% of the aromatase inhibitory activity of 4-PTAD.

  13. Reduced methadone clearance during aromatase inhibition.

    PubMed

    Lu, Wenjie Jessie; Thong, Nancy; Flockhart, David A

    2012-08-01

    Methadone is increasingly used in pain management and is a cornerstone in the treatment of opiate withdrawal. It is subject to highly variable clearance among patients. The complete metabolic disposition of methadone is likely to involve a number of enzymes, including specifically CYP2B6. Previous studies in vitro suggest that metabolism by aromatase may also contribute. Single-dose methadone pharmacokinetics (2 mg, intravenous) were studied in 15 healthy postmenopausal women in the presence and absence of a potent aromatase inhibitor, letrozole. A sequential design was used, involving a control period followed by treatment with letrozole (2.5 mg/d, 11 days), in which each subject served as her own control. On average, letrozole treatment reduced methadone systemic clearance by 22% (P = 0.001), increased methadone AUC by 23% (P = 0.007), and increased elimination half-life by 21% (P = 0.042). The plasma parent-to-metabolite ratio also increased (P = 0.009), and there was a linear relationship (R2 = 0.74) between change in this plasma ratio and change in methadone AUC0-∞. In contrast, there was no such association with change in apparent urinary methadone clearance. Letrozole did not change methadone distribution half-life or its volume of distribution. Overall, these data demonstrate a significant decrease in methadone clearance during coadministration of letrozole, consistent with decreased metabolism brought about by aromatase inhibition. An involvement of aromatase in the disposition of methadone may help explain the difficulty in methadone dosing and suggests a broader role for this catalyst of endogenous steroid metabolism in xenobiotic drug disposition.

  14. Induction and inhibition of aromatase (CYP19) activity by natural and synthetic flavonoid compounds in H295R human adrenocortical carcinoma cells.

    PubMed

    Sanderson, J Thomas; Hordijk, Joost; Denison, Michael S; Springsteel, Mark F; Nantz, Michael H; van den Berg, Martin

    2004-11-01

    Flavonoids and related structures (e.g., flavones, isoflavones, flavanones, catechins) exert various biological effects, including anticarcinogenic, antioxidant and (anti-)estrogenic effects, and modulation of sex hormone homeostasis. A key enzyme in the synthesis of estrogens from androgens is aromatase (cytochrome P450 19; CYP19). We investigated the effects of various natural and synthetic flavonoids on the catalytic activity and promoter-specific expression of aromatase in H295R human adrenocortical carcinoma cells. Natural flavones were consistently more potent inhibitors than flavanones. IC(50) values for 7-hydroxyflavone, chrysin, and apigenin were 4, 7, and 20 microM, respectively; for the flavanones 7-hydroxyflavanone and naringenin the IC(50) values were 65 and 85 microM, respectively. The steroidal aromatase inhibitor (positive control) 4-hydroxyandrostenedione had an IC(50) of 20 nM. The inhibition by apigenin and naringenin coincided with some degree of cytotoxicity at 100 microM. The natural flavonoid derivative rotenone (IC(50) 0.3 microM) was the most potent aromatase inhibitor tested. Several synthetic flavonoid and structurally related quinolin-4-one analogs inhibited aromatase activity. The most potent inhibitor was 4'-tert-butyl-quinolin-4-one (IC(50) 2 microM), followed by two 2-pyridinyl-substituted alpha-naphthoflavones (IC(50)s 5 and >30 microM). The two 2-pyridinyl-substituted gamma-naphthoflavones consistently produced biphasic concentration-response curves, causing about 1.5-fold aromatase induction at concentrations below 1 microM and inhibition above that level (IC(50)s 7 and >30 microM). The natural flavone quercetin and isoflavone genistein induced aromatase activity 4- and 2.5-fold induction, respectively, at 10 microM. This coincided with increased intracellular cAMP concentrations and increased levels of the cAMP-dependent pII and to a lesser extent 1.3 promoter-specific aromatase transcripts. These results shed light on the

  15. Comparative toxicity, oxidative stress and endocrine disruption potential of plasticizers in JEG-3 human placental cells.

    PubMed

    Pérez-Albaladejo, Elisabet; Fernandes, Denise; Lacorte, Silvia; Porte, Cinta

    2017-02-01

    Plasticizers are suspected to be toxic and/or to modulate or disrupt the endocrine system of humans and to cross the placental barrier, being embryonic and fetal development a particularly vulnerable period. This work investigates the comparative toxicity and ability to interfere with the synthesis of steroids and to generate reactive oxygen species (ROS) of a selected number of plasticizers, including bisphenol A (BPA), nonyl- (NP) and octylphenol (OP), benzyl butyl phthalate (BBP), dibutyl phthalate (DBP), di(2-ethylhexyl)phthalate (DEHP) and dimethyl phthalate (DMP), in the human placenta JEG-3 cells. Moreover, the bioavailability of chemicals in culture medium has been investigated. After 24h exposure, OP and NP showed the highest cytotoxicity (EC50: 36-40μM) followed by BPA (138-219μM), whereas no significant toxicity was observed for phthalates. Notwithstanding, BBP and DBP significantly decreased P450 aromatase activity (experimental IC50: 14-15μM), while NP and OP (20μM) increased the activity. Overall, this study evidences the differential toxicity and ability to modulate placental aromatase activity of some of the compounds nowadays used as plasticizers, and highlights the need of an accurate determination of the bioavailability of chemicals to improve the sensitivity of in-vitro tests.

  16. Aromatase regulates aggression in the African cichlid fish Astatotilapia burtoni.

    PubMed

    Huffman, Lin S; O'Connell, Lauren A; Hofmann, Hans A

    2013-03-15

    The roles of estrogen and androgens in male social behavior are well studied, but little is known about how these hormones contribute to behavior in a social hierarchy. Here we test the role of aromatase, the enzyme that converts testosterone into estradiol, in mediating aggression and reproductive behavior in male Astatotilapia burtoni, an African cichlid fish that displays remarkable plasticity in social behavior. We first measured aromatase expression in subordinate and dominant males in brain regions that regulate social behavior and found that subordinate males have higher aromatase expression than dominant males in the magnocellular and gigantocellular regions of the preoptic area. Next, we functionally tested the role of aromatase in regulating behavior by intraperitoneally injecting dominant males with either saline or fadrozole (FAD), an aromatase inhibitor, and found that FAD treatment decreases aggressive, but not reproductive, behaviors compared to saline controls. To determine the underlying physiological and molecular consequences of FAD treatment, we measured estradiol and testosterone levels from plasma and brain aromatase expression in FAD and saline treated dominant males. We found that estradiol levels decreased and testosterone levels increased in response to FAD treatment. Moreover, FAD treated males had increased aromatase expression in the gigantocellular portion of the POA, possibly a compensatory response. Overall, our results suggest aromatase is a key enzyme that promotes aggression in A. burtoni males through actions in the preoptic area.

  17. Natural Product Compounds with Aromatase Inhibitory Activity: An Update

    PubMed Central

    Balunas, Marcy J.; Kinghorn, A. Douglas

    2010-01-01

    Several synthetic aromatase inhibitors are currently in clinical use for the treatment of postmenopausal women with hormone-receptor positive breast cancer. However, these treatments may lead to untoward side effects and so a search for new aromatase inhibitors continues, especially those for which the activity is promoter-specific, targeting the breast-specific promoters I.3 and II. Recently, numerous natural product compounds have been found to inhibit aromatase in non-cellular, cellular, and in vivo studies. These investigations, covering the last two years, as well as additional studies that have focused on the evaluation of natural product compounds as promoter-specific aromatase inhibitors or as aromatase inducers, are described in this review. PMID:20635310

  18. Anti-tumor efficacy of new 7α-substituted androstanes as aromatase inhibitors in hormone-sensitive and resistant breast cancer cells.

    PubMed

    Amaral, Cristina; Varela, Carla L; Maurício, João; Sobral, Ana Filipa; Costa, Saul C; Roleira, Fernanda M F; Tavares-da-Silva, Elisiário J; Correia-da-Silva, Georgina; Teixeira, Natércia

    2017-04-07

    The majority of breast cancer cases are estrogen receptor positive (ER(+)). Although, third-generation aromatase inhibitors (AIs) are used as first-line treatment in post-menopausal women, they cause endocrine resistance and bone loss, which limits their success. Therefore, there is a demand to discover new potent molecules, with less toxicity that can circumvent these drawbacks. Our group has previously demonstrated that new 7α-substituted steroidal molecules, 7α-(2ξ,3ξ-epoxypropyl)androsta-1,4-diene-3,17-dione (3), 7α-allylandrost-4-ene-3,17-dione (6), 7α-allylandrost-4-en-17-one (9), 7α-allyl-3-oxoandrosta-1,4-dien-17β-ol (10) and 7α-allylandrosta-1,4-diene-3,17-dione (12) are potent AIs in placental microsomes. In this work, it was investigated their anti-aromatase activity and in vitro effects in sensitive and resistant breast cancer cells. All the steroids efficiently inhibit aromatase in breast cancer cells, allowing to establish new structure-activity relationships for this class of compounds. Moreover, the new AIs can inhibit breast cancer cell growth, by causing cell cycle arrest and apoptosis. The effects of AIs 3 and 12 on sensitive cells were dependent on aromatase inhibition and androgen receptor (AR), while for AI 9 and AI 10 were AR- and ER-dependent, respectively. In addition, it was shown that all the AIs can sensitize resistant cancer cells being their behavior similar to the sensitive cells. In summary, this study contributes to the understanding of the structural modifications in steroidal scaffold that are translated into better aromatase inhibition and anti-tumor properties, providing important information for the rational design/synthesis of more effective AIs. In addition, allowed the discovery of new potent 7α-substituted androstane molecules to inhibit tumor growth and prevent endocrine resistance.

  19. Pathogens and the Placental Fortress

    PubMed Central

    Robbins, Jennifer R.

    2011-01-01

    Summary Placental infections are major causes of maternal and fetal disease. This review introduces a new paradigm for placental infections based on current knowledge of placental defenses and how this barrier can be breached. Transmission of pathogens from mother to fetus can occur at two sites of direct contact between maternal cells and specialized fetal cells (trophoblasts) in the human placenta: (i) maternal immune and endothelial cells juxtaposed to extravillous trophoblasts in the uterine implantation site and (ii) maternal blood surrounding the syncytiotrophoblast. Recent findings suggest that the primary vulnerability is in the implantation site. We explore evidence that the placental syncytiotrophoblast evolved as a defense against pathogens, and that inflammation-mediated spontaneous abortion may benefit mother and pathogen. PMID:22169833

  20. Placental Growth Factor Administration Abolishes Placental Ischemia-Induced Hypertension.

    PubMed

    Spradley, Frank T; Tan, Adelene Y; Joo, Woo S; Daniels, Garrett; Kussie, Paul; Karumanchi, S Ananth; Granger, Joey P

    2016-04-01

    Preeclampsia is a pregnancy-specific disorder of new-onset hypertension. Unfortunately, the most effective treatment is early delivery of the fetus and placenta. Placental ischemia appears central to the pathogenesis of preeclampsia because placental ischemia/hypoxia induced in animals by reduced uterine perfusion pressure (RUPP) or in humans stimulates release of hypertensive placental factors into the maternal circulation. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes and reduces bioavailable vascular endothelial growth factor and placental growth factor (PlGF), is elevated in RUPP rats and preeclampsia. Although PlGF and vascular endothelial growth factor are both natural ligands for sFlt-1, vascular endothelial growth factor also has high affinity to VEGFR2 (Flk-1) causing side effects like edema. PlGF is specific for sFlt-1. We tested the hypothesis that PlGF treatment reduces placental ischemia-induced hypertension by antagonizing sFlt-1 without adverse consequences to the mother or fetus. On gestational day 14, rats were randomized to 4 groups: normal pregnant or RUPP±infusion of recombinant human PlGF (180 μg/kg per day; AG31, a purified, recombinant human form of PlGF) for 5 days via intraperitoneal osmotic minipumps. On day 19, mean arterial blood pressure and plasma sFlt-1 were higher and glomerular filtration rate lower in RUPP than normal pregnant rats. Infusion of recombinant human PlGF abolished these changes seen with RUPP along with reducing oxidative stress. These data indicate that the increased sFlt-1 and reduced PlGF resulting from placental ischemia contribute to maternal hypertension. Our novel finding that recombinant human PlGF abolishes placental ischemia-induced hypertension, without major adverse consequences, suggests a strong therapeutic potential for this growth factor in preeclampsia.

  1. PLACENTAL GROWTH FACTOR ADMINISTRATION ABOLISHES PLACENTAL ISCHEMIA-INDUCED HYPERTENSION

    PubMed Central

    Spradley, Frank T.; Tan, Adelene Y.; Joo, Woo S.; Daniels, Garrett; Kussie, Paul; Karumanchi, S. Ananth; Granger, Joey P.

    2016-01-01

    Preeclampsia is a pregnancy-specific disorder of new-onset hypertension. Unfortunately, the most effective treatment is early delivery of the fetus and placenta. Placental ischemia appears central to the pathogenesis of preeclampsia as placental ischemia/hypoxia induced in animals by reduced uterine perfusion pressure (RUPP) or in humans stimulates release of hypertensive placental factors into the maternal circulation. The anti-angiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), which antagonizes and reduces bioavailable vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), is elevated in RUPP rats and preeclampsia. Although PlGF and VEGF are both natural ligands for sFlt-1, VEGF also has high affinity to VEGFR2 (Flk-1) causing side effects like edema. PlGF is specific for sFlt-1. We tested the hypothesis that PlGF treatment reduces placental ischemia-induced hypertension by antagonizing sFlt-1 without adverse consequences to the mother or fetus. On gestational day 14, rats were randomized to four groups: normal pregnant (NP) or RUPP ± infusion of rhPlGF (180 μg/kg/day; AG31, a purified, recombinant human form of PlGF) for 5 days via intraperitoneal osmotic minipumps. On day 19, mean arterial blood pressure and plasma sFlt-1 were higher and glomerular filtration rate lower in RUPP than NP rats. Infusion of rhPlGF abolished these changes seen with RUPP along with reducing oxidative stress. These data indicate that the increased sFlt-1 and reduced PlGF resulting from placental ischemia contribute to maternal hypertension. Our novel finding that rhPlGF abolishes placental ischemia-induced hypertension, without major adverse consequences, suggests a strong therapeutic potential for this growth factor in preeclampsia. PMID:26831193

  2. Enzymic aromatization of 6-alkyl-substituted androgens, potent competitive and mechanism-based inhibitors of aromatase.

    PubMed

    Numazawa, M; Yoshimura, A; Oshibe, M

    1998-01-01

    To gain insight into the relationships between the aromatase inhibitory activity of 6-alkyl-substituted androgens, potent competitive inhibitors, and their ability to serve as a substrate of aromatase, we studied the aromatization of a series of 6alpha- and 6beta-alkyl (methyl, ethyl, n-propyl, n-pentyl and n-heptyl)-substituted androst-4-ene-3,17-diones (ADs) and their androsta-1,4-diene-3,17-dione (ADD) derivatives with human placental aromatase, by gas chromatography-mass spectrometry. Among the inhibitors examined, ADD and its 6alpha-alkyl derivatives with alkyl functions less than three carbons long, together with 6beta-methyl ADD, are suicide substrates of aromatase. All of the steroids, except for 6beta-n-pentyl ADD and its n-heptyl analogue as well as 6beta-n-heptyl AD, were found to be converted into the corresponding 6-alkyl oestrogens. The 6-methyl steroids were aromatized most efficiently in each series, and the aromatization rate essentially decreased in proportion to the length of the 6-alkyl chains in each series, where the 6alpha-alkyl androgens were more efficient substrates than the corresponding 6beta isomers. The Vmax of 6alpha-methyl ADD was approx. 2.5-fold that of the natural substrate AD and approx. 3-fold that of the parent ADD. On the basis of this, along with the facts that the rates of a mechanism-based inactivation of aromatase by ADD and its 6alpha-methyl derivative are similar, it is implied that alignment of 6alpha-methyl ADD in the active site could favour the pathway leading to oestrogen over the inactivation pathway, compared with that of ADD. The relative apparent Km values for the androgens obtained in this study are different from the relative Ki values obtained previously, indicating that there is a difference between the ability to serve as an inhibitor and the ability to serve as a substrate in the 6-alkyl androgen series.

  3. Aromatase excess in cancers of breast, endometrium and ovary.

    PubMed

    Bulun, Serdar E; Chen, Dong; Lu, Meiling; Zhao, Hong; Cheng, Youhong; Demura, Masashi; Yilmaz, Bertan; Martin, Regina; Utsunomiya, Hiroki; Thung, Steven; Su, Emily; Marsh, Erica; Hakim, Amy; Yin, Ping; Ishikawa, Hiroshi; Amin, Sanober; Imir, Gonca; Gurates, Bilgin; Attar, Erkut; Reierstad, Scott; Innes, Joy; Lin, Zhihong

    2007-01-01

    Pathogenesis and growth of three common women's cancers (breast, endometrium and ovary) are linked to estrogen. A single gene encodes the key enzyme for estrogen biosynthesis named aromatase, inhibition of which effectively eliminates estrogen production in the entire body. Aromatase inhibitors successfully treat breast cancer, whereas their roles in endometrial and ovarian cancers are less clear. Ovary, testis, adipose tissue, skin, hypothalamus and placenta express aromatase normally, whereas breast, endometrial and ovarian cancers overexpress aromatase and produce local estrogen exerting paracrine and intracrine effects. Tissue-specific promoters distributed over a 93-kb regulatory region upstream of a common coding region alternatively control aromatase expression. A distinct set of transcription factors regulates each promoter in a signaling pathway- and tissue-specific manner. In cancers of breast, endometrium and ovary, aromatase expression is primarly regulated by increased activity of the proximally located promoter I.3/II region. Promoters I.3 and II lie 215 bp from each other and are coordinately stimulated by PGE(2) via a cAMP-PKA-dependent pathway. In breast adipose fibroblasts exposed to PGE(2) secreted by malignant epithelial cells, PKC is also activated, and this potentiates cAMP-PKA-dependent induction of aromatase. Thus, inflammatory substances such as PGE(2) may play important roles in inducing local production of estrogen that promotes tumor growth.

  4. Weight gain increases human aromatase expression in mammary gland.

    PubMed

    Chen, Dong; Zhao, Hong; Coon, John S; Ono, Masanori; Pearson, Elizabeth K; Bulun, Serdar E

    2012-05-15

    Adulthood weight gain predicts estrogen receptor-positive breast cancer. Because local estrogen excess in the breast likely contributes to cancer development, and aromatase is the key enzyme in estrogen biosynthesis, we investigated the role of local aromatase expression in weight gain-associated breast cancer risk in a humanized aromatase (Arom(hum)) mouse model containing the coding region and the 5'-regulatory region of the human aromatase gene. Compared with littermates on normal chow, female Arom(hum) mice on a high fat diet gained more weight, and had a larger mammary gland mass with elevated total human aromatase mRNA levels via promoters I.4 and II associated with increased levels of their regulators TNFα and C/EBPβ. There was no difference in total human aromatase mRNA levels in gonadal white adipose tissue. Our data suggest that diet-induced weight gain preferentially stimulates local aromatase expression in the breast, which may lead to local estrogen excess and breast cancer risk.

  5. Flavonoid inhibition of aromatase enzyme activity in human preadipocytes.

    PubMed

    Campbell, D R; Kurzer, M S

    1993-09-01

    Eleven flavonoid compounds were compared with aminoglutethimide (AG), a pharmaceutical aromatase inhibitor, for their abilities to inhibit aromatase enzyme activity in a human preadipocyte cell culture system. Flavonoids exerting no effect on aromatase activity were catechin, daidzein, equol, genistein, beta-naphthoflavone (BNF), quercetin and rutin. The synthetic flavonoid, alpha-naphthoflavone (ANF), was the most potent aromatase inhibitor, with an I50 value of 0.5 microM. Three naturally-occurring flavonoids, chrysin, flavone, and genistein 4'-methyl ether (Biochanin A) showed I50 values of 4.6, 68, and 113 microM, respectively, while AG showed an I50 value of 7.4 microM. Kinetic analyses showed that both AG and the flavonoids acted as competitive inhibitors of aromatase. The Ki values, indicating the effectiveness of inhibition, were 0.2, 2.4, 2.4, 22, and 49 microM, for ANF, AG, chrysin, flavone, and Biochanin A, respectively. Chrysin, the most potent of the naturally-occurring flavonoids, was similar in potency and effectiveness to AG, a pharmaceutical aromatase inhibitor used clinically in cases of estrogen-dependent carcinoma. These data suggest that flavonoid inhibition of peripheral aromatase activity may contribute to the observed cancer-preventive hormonal effects of plant-based diets.

  6. Bone scan alterations in aromatase inhibitor-treated patients.

    PubMed

    De Geeter, Frank; Van den Bruel, Annick; De Cuypere, Eveline; Langlois, Michel

    2015-01-01

    We report bone scan changes in 3 patients receiving aromatase inhibitors as adjuvant treatment for postmenopausal hormone receptor-positive breast cancer. Compared with bone scans before treatment, repeated scans after at least 10 months of aromatase inhibitor treatment showed increased activity in the peripheral skeleton and the skull. In 2 patients, these alterations could be correlated with increased markers of bone turnover. They probably result from high bone turnover induced by estrogen depletion caused by aromatase inhibitors. This effect should be taken into account in the differential diagnosis of a bone scan pattern suggestive of hyperparathyroidism, which was ruled out.

  7. Programming placental nutrient transport capacity

    PubMed Central

    Fowden, A L; Ward, J W; Wooding, F P B; Forhead, A J; Constancia, M

    2006-01-01

    Many animal studies and human epidemiological findings have shown that impaired growth in utero is associated with physiological abnormalities in later life and have linked this to tissue programming during suboptimal intrauterine conditions at critical periods of development. However, few of these studies have considered the contribution of the placenta to the ensuing adult phenotype. In mammals, the major determinant of intrauterine growth is the placental nutrient supply, which, in turn, depends on the size, morphology, blood supply and transporter abundance of the placenta and on synthesis and metabolism of nutrients and hormones by the uteroplacental tissues. This review examines the regulation of placental nutrient transfer capacity and the potential programming effects of nutrition and glucocorticoid over-exposure on placental phenotype with particular emphasis on the role of the Igf2 gene in these processes. PMID:16439433

  8. Bisphenol A differentially activates protein kinase C isoforms in murine placental tissue.

    PubMed

    Tan, Wenjuan; Huang, Hui; Wang, Yanfei; Wong, Tsz Yan; Wang, C C; Leung, Lai K

    2013-06-01

    Bisphenol A is utilized to make polycarbonate plastics and is an environmental pollutant. Recent research has indicated that it is an endocrine disruptor and may interfere with reproductive processes. Our lab has previously shown that bisphenol A could regulate corticotrophin releasing hormone and aromatase in cultured placental cells. In the present study, the effect of bisphenol A on these two genes in the placenta was investigated in mice. Pregnant ICR mice were gavaged with bisphenol A at 2, 20 and 200mg/kg body weight/day from E13 to E16 and were euthanized at E17. Compared to the control mice, increased plasma estrogen and corticotrophin releasing hormone were observed in bisphenol A-treated mice. Messenger RNA quantification indicated that placental crh but not cyp19 was induced in mice treated with bisphenol A. Tracking the related signaling pathway, we found that protein kinase C ζ/λ and δ were activated in the placentas of bisphenol A-treated mice. As the gene promoter of crh contains CRE and the half site of ERE, either phospho-PKC or estrogen could stimulate the gene transactivation. These results indicate that bisphenol A might increase plasma concentrations of estradiol, testosterone, corticotrophin releasing hormone and placental phospho-PKC ζ/λ and δ in mice. Ultimately, the incidence of premature birth in these mice could increase.

  9. The effects of the standardized extracts of Ginkgo biloba on steroidogenesis pathways and aromatase activity in H295R human adrenocortical carcinoma cells

    PubMed Central

    2016-01-01

    Objectives Aromatase inhibitors that block estrogen synthesis are a proven first-line hormonal therapy for postmenopausal breast cancer. Although it is known that standardized extract of Ginkgo biloba (EGb761) induces anti-carcinogenic effects like the aromatase inhibitors, the effects of EGb761 on steroidogenesis have not been studied yet. Therefore, the effects of EGb761 on steroidogenesis and aromatase activity was studied using a H295R cell model, which was a good in vitro model to predict effects on human adrenal steroidogenesis. Methods Cortisol, aldosterone, testosterone, and 17β-estradiol were evaluated in the H295R cells by competitive enzyme-linked immunospecific assay after exposure to EGb761. Real-time polymerase chain reaction were performed to evaluate effects on critical genes in steroid hormone production, specifically cytochrome P450 (CYP11/ 17/19/21) and the hydroxysteroid dehydrogenases (3β-HSD2 and 17β-HSD1/4). Finally, aromatase activities were measured with a tritiated water-release assay and by western blotting analysis. Results H295R cells exposed to EGb761 (10 and 100 μg/mL) showed a significant decrease in 17β-estradiol and testosterone, but no change in aldosterone or cortisol. Genes (CYP19 and 17β-HSD1) related to the estrogen steroidogenesis were significantly decreased by EGb761. EGb761 treatment of H295R cells resulted in a significant decrease of aromatase activity as measured by the direct and indirect assays. The coding sequence/ Exon PII of CYP19 gene transcript and protein level of CYP19 were significantly decreased by EGb761. Conclusions These results suggest that EGb761 could regulate steroidogenesis-related genes such as CYP19 and 17β-HSD1, and lead to a decrease in 17β-estradiol and testosterone. The present study provides good information on potential therapeutic effects of EGb761 on estrogen dependent breast cancer. PMID:27188280

  10. Effectively nursing patients receiving aromatase inhibitor therapy.

    PubMed

    Wengström, Y

    2008-06-01

    Inhibiting estrogen production is a common means of preventing breast cancer recurrence. The aromatase inhibitors (AIs) are becoming the preferred treatment over tamoxifen as adjuvant therapy for postmenopausal women with hormone-sensitive early breast cancer. Like all adjuvant therapies, AIs have adverse events (AEs) associated with their use, many of which resemble symptoms common to menopause. Because of the greater efficacy of AIs in preventing breast cancer recurrence over tamoxifen, these AEs may be considered tolerable by many patients and often can be effectively managed and/or prevented. Educating patients about anticipated AEs may help them understand, accept, and cope with these AEs. This article reviews the AEs associated with different adjuvant AI treatments and highlights some strategies to manage them effectively. It also highlights the importance of patient education regarding AI therapy and involvement in treatment decisions, which may lead to better long-term adherence and ultimately to better outcomes.

  11. Aromatase deficiency, a rare syndrome: case report.

    PubMed

    Baykan, Emine Kartal; Erdoğan, Mehmet; Özen, Samim; Darcan, Şükran; Saygılı, L Füsun

    2013-01-01

    Aromatase deficiency (AD) is a rare autosomal recessive inheritance syndrome. Its worldwide incidence is unknown, and there are few case reports in the literature. Aromatase dysfunction develops due to CYP19A1 gene mutation and a decrease in estrogen synthesis. Estrogen deficiency can induce delayed epiphyseal closure, eunuchoid body habitus, osteopenia, and osteoporosis in both genders. Our patient was a 27-year-old male who presented with bone pain, recurrent bone fractures associated with minimal trauma starting in puberty, and a progressive increase in height. Laboratory tests revealed that the blood levels of follicle-stimulating hormone and luteinizing hormone were above normal, testosterone level was normal, and estrogen was undetectable. Plain bone radiography of the left wrist and hand demonstrated that the epiphyses were still unfused. Lumbar osteoporosis was detected in bone densitometry. In the genetic analysis, homozygous R375H guanine-adenine (G-A) mutation was detected in the CYP19A1 gene, and a diagnosis of AD was reached. Treatment with 25 μg transdermal estradiol was started. All family members were examined. Homozygous R375H G-A mutation was detected in the patient's younger brother. Heterozygous R375H G-A mutation was found in his mother, father, and older brother. In conclusion, this AD patient requires lifetime estrogen replacement in order to provide sufficient bone mineralization, to reduce the risk of bone fractures, and to lead a healthy life. The best method to prevent the possible complications is to diagnose the AD syndrome at early ages and to provide adequate estrogen replacement starting at puberty.

  12. Variable phenotypes associated with aromatase (CYP19) insufficiency in humans

    PubMed Central

    Lin, Lin; Ercan, Oya; Raza, Jamal; Burren, Christine P.; Creighton, Sarah M.; Auchus, Richard J.; Dattani, Mehul T.; Achermann, John C.

    2007-01-01

    Context The P450 enzyme aromatase (CYP19) plays a crucial role in the endocrine and paracrine biosynthesis of estrogens from androgens in many diverse estrogen-responsive tissues. Complete aromatase deficiency has been reported in a small number of 46,XX girls with genital ambiguity and absent pubertal development, but it is unknown whether non-classic phenotypes exist. Objective The objective of the study was to determine whether variant forms of aromatase insufficiency can occur in humans. Patients Four patients (46,XX) from three kindred with variable degrees of androgenization and pubertal failure. Methods Mutational analysis of CYP19 and assay of enzyme activity. Results Aromatase insufficiency resulting in genital ambiguity at birth, but with variable breast development at puberty (B2-B4), occurred in 46,XX patients from two kindred who harbored point mutations or single codon deletions (R435C, F234del). Absent puberty with minimal androgenization at birth was found in one girl with a deletion involving exon5 of CYP19 (exon5del), which would be predicted to lead to an in-frame deletion of 59 amino acids from the enzyme. Functional studies revealed low residual aromatase activity in the cases where breast development occurred. Conclusions These studies demonstrate that aromatase mutations can produce variable or “non-classic” phenotypes in humans. Low residual aromatase activity may be sufficient for breast and uterine development to occur at puberty, despite significant androgenization in utero. Such phenotypic variability may be influenced further by modifying factors, such as non-classic pathways of estrogen synthesis, variability in co-regulators, or differences in androgen responsiveness. PMID:17164303

  13. Differential Regulation of Aromatase Isoforms and Tissue Responses to Environmental Chemicals in Fish

    EPA Science Inventory

    As in mammals, aromatase plays a basic role in fish reproduction. Unlike most mammals, with only one form of aromatase, fish have two distinct forms. One isoform, P450aromA, predominates in ovaries. Ovarian aromatase activity controls circulating levels of estrogens and is critic...

  14. The potency and clinical efficacy of aromatase inhibitors across the breast cancer continuum

    PubMed Central

    Lønning, P. E.

    2011-01-01

    The strategy of using estrogen suppression to treat breast cancer led to the development of aromatase inhibitors, including the third-generation nonsteroidal compounds anastrozole and letrozole, and the steroidal compound exemestane. Aromatase inhibitors potently inhibit aromatase activity and also suppress estrogen levels in plasma and tissue. In clinical studies in postmenopausal women with breast cancer, third-generation aromatase inhibitors were shown superior to tamoxifen for the treatment of metastatic disease. Studies of adjuvant therapy with aromatase inhibitors include (i) head-to-head studies of 5 years of the aromatase inhibitor versus 5 years of tamoxifen monotherapy; (ii) sequential therapy of 2–3 years of tamoxifen followed by an aromatase inhibitor (or the opposite sequence) versus 5 years of tamoxifen monotherapy; (iii) extended therapy with an aromatase inhibitor after 5 years of tamoxifen; and (iv) sequential therapy with an aromatase inhibitor versus aromatase inhibitor monotherapy. Recent results from the Arimidex, Tamoxifen, Alone or in Combination and Breast International Group 1–98 trials advocate using an aromatase inhibitor upfront. This article examines the clinical data with aromatase inhibitors, following a brief summary of their pharmacology. PMID:20616198

  15. Exploring new chemical functionalities to improve aromatase inhibition of steroids.

    PubMed

    Varela, Carla L; Amaral, Cristina; Correia-da-Silva, Georgina; Costa, Saul C; Carvalho, Rui A; Costa, Giosuè; Alcaro, Stefano; Teixeira, Natércia A A; Tavares-da-Silva, Elisiário J; Roleira, Fernanda M F

    2016-06-15

    In this work, new potent steroidal aromatase inhibitors both in microsomes and in breast cancer cells have been found. The synthesis of the 3,4-(ethylenedioxy)androsta-3,5-dien-17-one (12), a new steroid containing a heterocycle dioxene fused in the A-ring, led to the discovery of a new reaction for which a mechanism is proposed. New structure-activity relationships were established. Some 5β-steroids, such as compound 4β,5β-epoxyandrostan-17-one (9), showed aromatase inhibitory activity, because they adopt a similar A-ring conformation as those of androstenedione, the natural substrate of aromatase. Moreover, new chemical features to increase planarity were disclosed, specifically the 3α,4α-cyclopropane ring, as in 3α,4α-methylen-5α-androstan-17-one (5) (IC50=0.11μM), and the Δ(9-11) double bond in the C-ring, as in androsta-4,9(11)-diene-3,17-dione (13) (IC50=0.25μM). In addition, induced-fit docking (IFD) simulations and site of metabolism (SoM) predictions helped to explain the recognition of new potent steroidal aromatase inhibitors within the enzyme. These insights can be valuable tools for the understanding of the molecular recognition process by the aromatase and for the future design of new steroidal inhibitors.

  16. Ovarian and placental morphology and endocrine functions in the pregnant giraffe (Giraffa camelopardalis).

    PubMed

    Wilsher, S; Stansfield, F; Greenwood, R E S; Trethowan, P D; Anderson, R A; Wooding, F B W; Allen, W R

    2013-06-01

    Gross, histological and immunocytochemical examinations carried out on maternal and fetal reproductive tissues from two pregnant giraffes at an estimated 8 and 13.5 months of gestation (term=15 months) revealed a typically ruminant macrocotyledonary placenta with binucleate trophoblast cells scattered sparsely in the placentome where they stained intensely with a prolactin antiserum. Binucleate cells were present in greater numbers in the intercotyledonary allantochorion where they did not stain for prolactin whereas the uninucleate trophoblast still did. A single large corpus luteum of pregnancy and several small luteinised follicles were present in the maternal ovaries while the fetal ovaries at 13.5 months gestation showed an assortment of enlarging antral follicles and partially and completely lutenised follicles, the granulosa and luteal cells of which stained positively for 3β-hydroxysteroid dehydrogenase (3β-HSD), 17,20 lyase, prolactin, progesterone receptor and androgen receptor, but negatively for aromatase. The uninucleate trophoblast of the placentome and intercotyledonary allantochorion, the epithelium of the maternal endometrial glands, the seminiferous epithelium in the fetal testis at 8 months of gestation and the zonae fasciculata and reticularis of the fetal adrenal at 13.5 months also stained positively for 3β-HSD and negatively for aromatase. Endocrinologically, it appears that the giraffe placenta is more similar to that of the sheep than the cow with a placental lactogen as the likely driver of the considerable degree of luteinisation seen in both the maternal and the fetal ovaries.

  17. Aromatase inhibitors in stimulated IVF cycles

    PubMed Central

    2011-01-01

    Aromatase inhibitors have been introduced as a new treatment modality that could challenge clomiphene citrate as an ovulation induction regiment in patients with PCOS. Although several randomized trials have been conducted regarding their use as ovulation induction agents, only few trials are available regarding their efficacy in IVF stimulated cycles. Current available evidence support that letrozole may have a promising role in stimulated IVF cycles, either when administered during the follicular phase for ovarian stimulation. Especially for women with poor ovarian response, letrozole appears to have the potential to increase clinical pregnancy rates when combined with gonadotropins, whereas at the same time reduces the total gonadotropin dose required for ovarian stimulation. However, given that in all of the trials letrozole has been administered in GnRH antagonist cycles, it is intriguing to test in the future how it may perform when used in GnRH agonist cycles. Finally administration of letrozole during luteal phase in IVF cycles offers another treatment modality for patients at high risk for OHSS taking into account that it drastically reduces estradiol levels PMID:21693033

  18. TRPA1 Mediates Aromatase Inhibitor-Evoked Pain by the Aromatase Substrate Androstenedione.

    PubMed

    De Logu, Francesco; Tonello, Raquel; Materazzi, Serena; Nassini, Romina; Fusi, Camilla; Coppi, Elisabetta; Li Puma, Simone; Marone, Ilaria M; Sadofsky, Laura R; Morice, Alyn H; Susini, Tommaso; Terreni, Alessandro; Moneti, Gloriano; Di Tommaso, Mariarosaria; Geppetti, Pierangelo; Benemei, Silvia

    2016-12-01

    Aromatase inhibitors (AI) induce painful musculoskeletal symptoms (AIMSS), which are dependent upon the pain transducing receptor TRPA1. However, as the AI concentrations required to engage TRPA1 in mice are higher than those found in the plasma of patients, we hypothesized that additional factors may cooperate to induce AIMSS. Here we report that the aromatase substrate androstenedione, unique among several steroid hormones, targeted TRPA1 in peptidergic primary sensory neurons in rodent and human cells expressing the native or recombinant channel. Androstenedione dramatically lowered the concentration of letrozole required to engage TRPA1. Notably, addition of a minimal dose of androstenedione to physiologically ineffective doses of letrozole and oxidative stress byproducts produces AIMSS-like behaviors and neurogenic inflammatory responses in mice. Elevated androstenedione levels cooperated with low letrozole concentrations and inflammatory mediators were sufficient to provoke AIMSS-like behaviors. The generation of such painful conditions by small quantities of simultaneously administered TRPA1 agonists justifies previous failure to identify a precise link between AIs and AIMSS, underscoring the potential of channel antagonists to treat AIMSS. Cancer Res; 76(23); 7024-35. ©2016 AACR.

  19. Developing predictive approaches to characterize adaptive responses of the reproductive endocrine axis to aromatase inhibition: II. Computational modeling.

    PubMed

    Breen, Miyuki; Villeneuve, Daniel L; Ankley, Gerald T; Bencic, David C; Breen, Michael S; Watanabe, Karen H; Lloyd, Alun L; Conolly, Rory B

    2013-06-01

    Endocrine-disrupting chemicals can affect reproduction and development in humans and wildlife. We developed a computational model of the hypothalamic-pituitary-gonadal (HPG) axis in female fathead minnows to predict dose-response and time-course (DRTC) behaviors for endocrine effects of the aromatase inhibitor, fadrozole (FAD). The model describes adaptive responses to endocrine stress involving regulated secretion of a generic gonadotropin (LH/FSH) from the hypothalamic-pituitary complex. For model development, we used plasma 17β-estradiol (E2) concentrations and ovarian cytochrome P450 (CYP) 19A aromatase mRNA data from two time-course experiments, each of which included both an exposure and a depuration phase, and plasma E2 data from a third 4-day study. Model parameters were estimated using E2 concentrations for 0, 0.5, and 3 µg/l FAD exposure concentrations, and good fits to these data were obtained. The model accurately predicted CYP19A mRNA fold changes for controls and three FAD doses (0, 0.5, and 3 µg/l) and plasma E2 dose response from the 4-day study. Comparing the model-predicted DRTC with experimental data provided insight into how the feedback control mechanisms in the HPG axis mediate these changes: specifically, adaptive changes in plasma E2 levels occurring during exposure and "overshoot" occurring postexposure. This study demonstrates the value of mechanistic modeling to examine and predict dynamic behaviors in perturbed systems. As this work progresses, we will obtain a refined understanding of how adaptive responses within the vertebrate HPG axis affect DRTC behaviors for aromatase inhibitors and other types of endocrine-active chemicals and apply that knowledge in support of risk assessments.

  20. Placental calcification: a metastatic process?

    PubMed

    Poggi, S H; Bostrom, K I; Demer, L L; Skinner, H C; Koos, B J

    2001-07-01

    Placental calcification commonly increases with gestational age. The mechanism of apatite mineralization probably involves one of three known mechanisms of tissue calcification: physiological (like bone), dystrophic (ischaemia-related) or metastatic (mineralization in a supersaturated environment). This study was designed to determine the mechanism of calcification by examining (1) the mineral content of placental calcifications in comparison to other physiological and pathological apatites, and (2) the expression of bone morphogenetic proteins (BMPs), which are important in physiological calcification, across gestational age. By energy-dispersive x-ray analysis (EDXA), the Ca/P weight ratio for apatitic mineral from mature calcifications was 2.00+/-0.05 (s.e.), which is similar to that for stones formed in a metastatic, supersaturated environment and lower than that observed in physiological calcification. Biologically active BMP, which was determined by bioassay, was demonstrated in mature and postmature placentae. The BMPs PLAB, PDF and related protein INSL-4 were identified by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), but their mRNA expression was independent of gestational age (7-41 weeks of gestation). We conclude that (1) the identified BMPs were not related directly to placental calcification, which argues against physiological calcification, and (2) the chemical composition of the apatitic mineral was suggestive of rapid formation in a supersaturated environment, which is consistent with a metastatic mechanism of calcification.

  1. The control of preoptic aromatase activity by afferent inputs in Japanese quail.

    PubMed

    Absil, P; Baillien, M; Ball, G F; Panzica, G C; Balthazart, J

    2001-11-01

    This review summarizes current knowledge on the mechanisms that control aromatase activity in the quail preoptic area, a brain region that plays a key role in the control of reproduction. Aromatase and aromatase mRNA synthesis in the preoptic area are enhanced by testosterone and its metabolite estradiol, but estradiol receptors of the alpha subtype are not regularly colocalized with aromatase. Estradiol receptors of the beta subtype are present in the preoptic area but it is not yet known whether these receptors are colocalized with aromatase. The regulation by estrogen of aromatase activity may be, in part, trans-synaptically mediated, in a manner that is reminiscent of the ways in which steroids control the activity of gonadotropic hormone releasing hormone neurons. Aromatase-immunoreactive neurons are surrounded by dense networks of vasotocin-immunoreactive and tyrosine hydroxylase-immunoreactive fibers and punctate structures. These inputs are in part steroid-sensitive and could therefore mediate the effects of steroids on aromatase activity. In vivo pharmacological experiments indicate that catecholaminergic depletions significantly affect aromatase activity presumably by modulating aromatase transcription. In addition, in vitro studies on brain homogenates or on preoptic-hypothalamic explants show that aromatase activity can be rapidly modulated by a variety of dopaminergic compounds. These effects do not appear to be mediated by the membrane dopamine receptors and could involve changes in the phosphorylation state of the enzyme. Together, these results provide converging evidence for a direct control of aromatase activity by catecholamines consistent with the anatomical data indicating the presence of a catecholaminergic innervation of aromatase cells. These dopamine-induced changes in aromatase activity are observed after several hours or days and presumably result from changes in aromatase transcription but rapid non-genomic controls have also been

  2. Aromatase Inhibitor Associated Musculoskeletal Symptoms are associated with Reduced Physical Activity among Breast Cancer Survivors

    PubMed Central

    Brown, Justin C.; Mao, Jun J.; Stricker, Carrie; Hwang, Wei-Ting; Tan, Kay-See; Schmitz, Kathryn H.

    2014-01-01

    Background Physical activity has numerous health benefits for breast cancer survivors. Recent data suggest that some breast cancer survivors treated with aromatase inhibitors may experience aromatase inhibitor associated musculoskeletal symptoms. It is unknown whether aromatase inhibitor associated musculoskeletal symptoms are associated with reduced physical activity and what other risk factors are associated with such physical activity reductions. Methods We conducted a cross-sectional study at a large university-based breast cancer clinic among breast cancer survivors prescribed an aromatase inhibitor. At routine follow-up, we surveyed participants about aromatase inhibitor associated musculoskeletal symptoms, as well as pre-aromatase inhibitor, and current, physical activity levels. Results Among 300 participants, 90 (30%) reported a reduction of physical activity since the initiation of aromatase inhibitor therapy. Those with aromatase inhibitor associated musculoskeletal symptoms were more likely to report decreased physical activity (62% versus 38%, p=0.001) compared to those without aromatase inhibitor associated musculoskeletal symptoms. In multivariate analyses, aromatase inhibitor associated musculoskeletal symptoms [odds ratio (OR) =2.29 (95% confidence interval (CI): 1.36–3.86)], and body mass index [OR=1.06 (95% CI: 1.02–1.12)] were associated with reductions in physical activity. In subgroup analysis among breast cancer survivors with aromatase inhibitor associated musculoskeletal symptoms, self-reported lower extremity joint pain [OR=1.23 (95% CI: 1.00–1.50)] and impaired lower extremity physical function [OR=1.07 (95% CI: 1.01–1.14)] were associated with reductions in physical activity. Conclusion Breast cancer survivors with aromatase inhibitor associated musculoskeletal symptoms were more likely to report reductions in physical activity since initiating aromatase inhibitor therapy compared to those without aromatase inhibitor associated

  3. Persistent endocrine disruption effects in medaka fish with early life-stage exposure to a triazole-containing aromatase inhibitor (letrozole).

    PubMed

    Liao, Pei-Han; Chu, Szu-Hung; Tu, Tzu-Yi; Wang, Xiao-Huan; Lin, Angela Yu-Chen; Chen, Pei-Jen

    2014-07-30

    Letrozole (LET) is a triazole-containing drug that can inhibit the activity of cytochrome P450 aromatase. It is an environmentally emerging pollutant because of its broad use in medicine and frequent occurrence in aquifers receiving the effluent of municipal or hospital wastewater. However, the toxic impact of LET on fish populations remains unclear. We exposed medaka fish (Oryzias latipes) at an early stage of sexual development to a continuous chronic LET at environmentally relevant concentrations and assessed the endocrine disruption effects in adulthood and the next generation. LET exposure at an early life stage persistently altered phenotypic sex development and reproduction in adults and skewed the sex ratio in progeny. As well, LET exposure led to a gender-different endocrine disruption as seen by the interruption in gene expression responsible for estrogen synthesis and metabolism and fish reproduction. LET interfering with the aromatase system in early life stages of medaka can disrupt hormone homeostasis and reproduction. This potent aromatase inhibitor has potential ecotoxicological impact on fish populations in aquatic environments.

  4. Molecular modeling evaluation of non-steroidal aromatase inhibitors.

    PubMed

    Narayana, Bheemanapalli Lakshmi; Pran Kishore, Deb; Balakumar, Chadrasekaran; Rao, Kaki Venkata; Kaur, Rajwinder; Rao, Akkinepally Raghuram; Murthy, Javali Narashima; Ravikumar, Muttineni

    2012-05-01

    A recent discovery of aromatase crystal structure triggered the efforts to design novel aromatase inhibitors for breast cancer therapy. While correlating docking scores with inhibitory potencies of known ligands, feeble robustness of scoring functions toward prediction was observed. This prompted us to develop new prediction models using stepwise regression analysis based on consensus of different docking and their scoring methods (GOLD, LIGANDFIT, and GLIDE). Quantitative structure-activity relationships were developed between the aromatase inhibitory activity (pIC(50) ) of flavonoid derivatives (n=39) and docking scores and docking descriptors. QSAR models have been validated internally [using leave-one-out cross-validated r(2)(cv) (LOO-Q2))] and externally to ensure the predictive capacity of the models. Model 2 [M2] developed using consensus of docking scores of scoring functions viz. ASP, potential of mean force and DOCK Score (r(2)(cv)=0.850, r(2) = 0.870, r(2)(pred) = 0.633, RMSE = 0.363 μm, r(2)(m(test)) =0.831, r(2)(m(overall)) =0.832) was found to be better in predicting aromatase inhibitory potency (pIC(50) ) compared to the Model 1 [M1] based on docking descriptors (r(2)(cv)= 0.848, r(2) = 0.825, r(2)(pred) =0.788, RMSE=0.421μm, r(2)(m(test)) =0.808, r(2)(m(overall)) =0.821). It has been observed that the natural flavonoids and their derivatives were less potent compared to these scaffolds with imidazolylmethyl substitution owing to the interaction of nitrogen atom of the imidazole ring toward the heme (Fe(3+) ) of the aromatase. Results confirm the potential of our methodology for the design of new potent non-steroidal aromatase inhibitors.

  5. Regulation of aromatase expression in breast cancer tissue.

    PubMed

    Bulun, S E; Lin, Z; Zhao, H; Lu, M; Amin, S; Reierstad, S; Chen, D

    2009-02-01

    Epithelial-stromal interactions play key roles for aromatase expression and estrogen production in breast cancer tissue. Upregulated aromatase expression in breast fibroblasts increases the tissue concentration of estradiol (E2), which then activates a large number of carcinogenic genes via estrogen receptor-alpha (ERalpha) in malignant epithelial cells. This clinically pertains, since aromatase inhibitors (AIs) are the most effective hormonal treatment of ERalpha-positive breast tumors. A single gene encodes aromatase, the key enzyme in estrogen biosynthesis, the inhibition of which by an AI effectively eliminates E2 production. Since alternative promoters regulated by distinct signaling pathways control aromatase expression, it is possible to target these pathways and inhibit estrogen production in a tissue-selective fashion. We and others previously found that the majority of estrogen production in breast cancer tissue was accounted for by the aberrant activation of the proximal promoter I.3/II region. PGE(2) that is secreted in large amounts by malignant breast epithelial cells is the most potent known natural inducer of this promoter region in breast adipose fibroblasts. Signaling effectors/transcriptional regulators that mediate PGE(2) action include the activator pathways p38/CREB-ATF and JNK/jun and the inhibitory factor BRCA1 in breast adipose fibroblasts. Selective inhibition of this promoter region may treat breast cancer while permitting aromatase expression via alternative promoters in the brain and bone and thus obviate the key side effects of the current AIs. The signaling pathways that mediate the regulation of the promoter I.3/II region in undifferentiated fibroblasts in malignant breast tumors are reviewed.

  6. [Progress in study of the structure, catalytic mechanism and inhibitors of aromatase].

    PubMed

    Fu, Jing; Shen, Zhong-Hua; Cheng, Fei-Xiong; Liu, Gui-Xia; Li, Wei-Hua; Tang, Yun

    2012-01-01

    Aromatase is a key enzyme responsible for in vivo estrogen biosynthesis. Inhibition of the activity of the aromatase has become an alterative way for treatment of breast cancer. In this review, the structure and catalytic mechanism of the aromatase is briefly introduced followed by thorough review of the progress in the study of the steroidal and non-steroidal aromatase inhibitors. This review is focused on the natural compounds that exhibit the aromatase inhibition, which include flavonoids, xanthones, coumarins, and sesquiterpenes. The structure-activity relationship of these compounds is also discussed.

  7. New 7,8-benzoflavanones as potent aromatase inhibitors: synthesis and biological evaluation.

    PubMed

    Yahiaoui, Samir; Fagnere, Catherine; Pouget, Christelle; Buxeraud, Jacques; Chulia, Albert-José

    2008-02-01

    Some natural compounds such as flavonoids are known to possess a moderate inhibitory activity against aromatase, this enzyme being an interesting target for hormone-dependent breast cancer treatment. It has been demonstrated that the modulation of flavonoid skeleton could increase anti-aromatase effect. Therefore, new 7,8-benzoflavanones were synthesized and tested for their activity toward aromatase inhibition. It was observed that the introduction of a benzo ring at position C-7 and C-8 on flavanone skeleton led to new potent aromatase inhibitors, the resulting 7,8-benzoflavanones being until nine times more potent than aminogluthetimide (the first aromatase inhibitor used clinically).

  8. Clinical utilities of aromatase inhibitors in breast cancer

    PubMed Central

    Chumsri, Saranya

    2015-01-01

    Aromatase is an enzyme that converts testosterones to estrogens. Inhibition of this enzyme has been shown to have several clinical utilities in breast cancer. Currently, there are three aromatase inhibitors (AIs) in clinical use, namely anastrozole, letrozole, and exemestane. AIs have been used in various clinical settings for breast cancer, ranging from chemoprevention in breast cancer to treating breast cancer in both early stage in the adjuvant setting and metastatic disease. This article reviews mechanism of action, AI classification, and clinical utilities of AIs in various clinical settings in the context of breast cancer. PMID:26005359

  9. Pregnancy maintenance and the regulation of placental progesterone biosynthesis in the baboon.

    PubMed

    Henson, M C

    1998-01-01

    Progesterone (P4), a major steroid hormone produced by the ovarian corpus luteum (CL) and the placental syncytiotrophoblast, is considered essential for the successful maintenance of mammalian pregnancy. It has been demonstrated in our laboratory and in the laboratories of others, that the baboon (Papio anubis/cynocephalus) is an excellent model for study of the endocrinology of human pregnancy. Results from both in-vivo and in-vitro experiments indicate that oestrogen stimulates placental P4 production by regulation of cholesterol side chain cleavage cytochrome P-450 and through the uptake of cholesterol via the low density lipoprotein (LDL) pathway. Thus, LDL uptake by the baboon placental syncytiotrophoblast increases in response to maternal oestrogen concentration, which increases with advancing gestation. Conversely, both placental LDL uptake and maternal peripheral P4 concentration decline significantly at mid- to late gestation as a result of oestrogen deprivation by either anti-oestrogen administration or the removal of fetal androgen oestrogen precursors through fetectomy. Utilizing these methods, it has been possible to decrease cellular uptake of LDL-cholesterol and, hence, maternal peripheral P4 to only a small fraction of their normal concentrations, although P4 is still detected in the maternal periphery in concentrations adequate for preservation of the conceptus. We postulate that such levels of maternal P4 are derived from cholesterol precursor provided by sources alternate to the classical LDL-receptor pathway and are produced throughout gestation by the placental syncytiotrophoblast and perhaps during late pregnancy by a resurgent CL. We further postulate that regulation of these ancillary sources of cholesterol substrate is subject to LDL-cholesterol availability in the maternal peripheral circulation and to possible ontogenetic changes in both primary and secondary cholesterol-yielding mechanisms, which may be divergently regulated in the

  10. Mammographic Breast Density Response to Aromatase Inhibition

    PubMed Central

    Vachon, Celine M.; Suman, Vera J.; Brandt, Kathleen R.; Kosel, Matthew L.; Buzdar, Aman U.; Olson, Janet E.; Wu, Fang-Fang; Flickinger, Lynn M.; Ursin, Giske; Elliott, Catherine R.; Shepherd, Lois; Weinshilboum, Richard M.; Goss, Paul E.; Ingle, James N.

    2013-01-01

    Purpose Mammographic breast density (MBD) is decreased by tamoxifen, but the effect of aromatase inhibitors (AI) is less clear. Experimental Design We enrolled early stage postmenopausal breast cancer patients initiating adjuvant AI therapy and ascertained mammograms before and at an average 10 months of AI therapy. We matched cases to healthy postmenopausal women (controls) from a large mammography screening cohort on age, baseline body mass index, baseline MBD and interval between mammograms. We estimated change in MBD using a computer-assisted thresholding program (Cumulus) and compared differences between cases and matched controls. Results In predominantly white women (96%), we found 14% of the 387 eligible cases had a MBD reduction of at least 5% after an average of 10 months of AI therapy. MBD reductions were associated with higher baseline MBD, AI use for more than 12 months and prior postmenopausal hormone use. Comparing each case to her matched control, there was no evidence of an association of change in MBD with AI therapy (median case-control difference among 369 pairs was −0.1% (10th and 90th percentile: −5.9%, 5.2%) p=0.51). Case-control differences were similar by type of AI (p’s 0.41 and 0.56); prior use of postmenopausal hormones (p=0.85); baseline MBD (p=0.55); or length of AI therapy (p=0.08). Conclusions In postmenopausal women treated with AIs, 14% of cases had a MBD reduction of >5%, but these decreases did not differ from matched controls. These data suggest that MBD is not a clinically useful biomarker for predicting the value of AI therapy in white postmenopausal women. PMID:23468058

  11. Potential utility of natural products as regulators of breast cancer-associated aromatase promoters

    PubMed Central

    2011-01-01

    Aromatase, the key enzyme in estrogen biosynthesis, converts androstenedione to estrone and testosterone to estradiol. The enzyme is expressed in various tissues such as ovary, placenta, bone, brain, skin, and adipose tissue. Aromatase enzyme is encoded by a single gene CYP 19A1 and its expression is controlled by tissue-specific promoters. Aromatase mRNA is primarily transcribed from promoter I.4 in normal breast tissue and physiological levels of aromatase are found in breast adipose stromal fibroblasts. Under the conditions of breast cancer, as a result of the activation of a distinct set of aromatase promoters (I.3, II, and I.7) aromatase expression is enhanced leading to local overproduction of estrogen that promotes breast cancer. Aromatase is considered as a potential target for endocrine treatment of breast cancer but due to nonspecific reduction of aromatase activity in other tissues, aromatase inhibitors (AIs) are associated with undesirable side effects such as bone loss, and abnormal lipid metabolism. Inhibition of aromatase expression by inactivating breast tumor-specific aromatase promoters can selectively block estrogen production at the tumor site. Although several synthetic chemical compounds and nuclear receptor ligands are known to inhibit the activity of the tumor-specific aromatase promoters, further development of more specific and efficacious drugs without adverse effects is still warranted. Plants are rich in chemopreventive agents that have a great potential to be used in chemotherapy for hormone dependent breast cancer which could serve as a source for natural AIs. In this brief review, we summarize the studies on phytochemicals such as biochanin A, genistein, quercetin, isoliquiritigenin, resveratrol, and grape seed extracts related to their effect on the activation of breast cancer-associated aromatase promoters and discuss their aromatase inhibitory potential to be used as safer chemotherapeutic agents for specific hormone

  12. Potential utility of natural products as regulators of breast cancer-associated aromatase promoters.

    PubMed

    Khan, Shabana I; Zhao, Jianping; Khan, Ikhlas A; Walker, Larry A; Dasmahapatra, Asok K

    2011-06-21

    Aromatase, the key enzyme in estrogen biosynthesis, converts androstenedione to estrone and testosterone to estradiol. The enzyme is expressed in various tissues such as ovary, placenta, bone, brain, skin, and adipose tissue. Aromatase enzyme is encoded by a single gene CYP 19A1 and its expression is controlled by tissue-specific promoters. Aromatase mRNA is primarily transcribed from promoter I.4 in normal breast tissue and physiological levels of aromatase are found in breast adipose stromal fibroblasts. Under the conditions of breast cancer, as a result of the activation of a distinct set of aromatase promoters (I.3, II, and I.7) aromatase expression is enhanced leading to local overproduction of estrogen that promotes breast cancer. Aromatase is considered as a potential target for endocrine treatment of breast cancer but due to nonspecific reduction of aromatase activity in other tissues, aromatase inhibitors (AIs) are associated with undesirable side effects such as bone loss, and abnormal lipid metabolism. Inhibition of aromatase expression by inactivating breast tumor-specific aromatase promoters can selectively block estrogen production at the tumor site. Although several synthetic chemical compounds and nuclear receptor ligands are known to inhibit the activity of the tumor-specific aromatase promoters, further development of more specific and efficacious drugs without adverse effects is still warranted. Plants are rich in chemopreventive agents that have a great potential to be used in chemotherapy for hormone dependent breast cancer which could serve as a source for natural AIs. In this brief review, we summarize the studies on phytochemicals such as biochanin A, genistein, quercetin, isoliquiritigenin, resveratrol, and grape seed extracts related to their effect on the activation of breast cancer-associated aromatase promoters and discuss their aromatase inhibitory potential to be used as safer chemotherapeutic agents for specific hormone

  13. Microparasites and Placental Invasiveness in Eutherian Mammals

    PubMed Central

    Capellini, Isabella; Nunn, Charles L.; Barton, Robert A.

    2015-01-01

    Placental invasiveness—the number of maternal tissue layers separating fetal tissues from maternal blood—is variable across mammalian species. Although this diversity is likely to be functionally important, variation in placental invasiveness remains unexplained. Here we test the hypothesis that increased risk of transplacental transmission of pathogens from the mother to the fetus promotes the evolution of non-invasive placentation, the most likely derived condition in eutherian mammals. Specifically, we predict that non-invasive placentation is associated with increased microparasite species richness relative to more invasive placental types, based on the assumption that higher numbers of microparasites in a population reflects greater risk of transplacental transmission to fetuses. As predicted, higher bacteria species richness is associated with non-invasive placentation. Protozoa species richness, however, shows the opposite pattern. Because invasive placentae facilitate the transfer of maternal antibodies to the fetus, we propose that the ancestral condition of invasive placentation is retained under selection for protection of newborns from higher risk of postnatal protozoan infection. Hence, our findings suggest that a tradeoff exists between protection against bacterial infection prenatally and protozoan infection postnatally. Future studies are needed to investigate how maternal prevalence of infection and the relative pre- versus postnatal risk of fetal infection by different microparasite groups vary among mammalian hosts in relation to placental invasiveness. PMID:26168031

  14. Dietary composition programmes placental phenotype in mice.

    PubMed

    Coan, P M; Vaughan, O R; McCarthy, J; Mactier, C; Burton, G J; Constância, M; Fowden, A L

    2011-07-15

    Dietary composition during pregnancy influences fetal and adult phenotype but its effects on placental phenotype remain largely unknown. Using molecular, morphological and functional analyses, placental nutrient transfer capacity was examined in mice fed isocaloric diets containing 23%, 18% or 9% casein (C) during pregnancy. At day 16, placental transfer of glucose, but not methyl-aminoisobutyric acid (MeAIB), was greater in C18 and C9 than C23 mice, in association with increased placental expression of the glucose transporter Slc2a1/GLUT1, and the growth factor Igf2. At day 19, placental glucose transport remained high in C9 mice while MeAIB transfer was less in C18 than C23 mice, despite greater placental weights in C18 and C9 than C23 mice. Placental System A amino acid transporter expression correlated with protein intake at day 19. Relative growth of transport verses endocrine zones of the placenta was influenced by diet at both ages without changing the absolute volume of the transport surface. Fetal weight was unaffected by diet at day 16 but was reduced in C9 animals by day 19. Morphological and functional adaptations in placental phenotype, therefore, occur to optimise nutrient transfer when dietary composition is varied, even subtly. This has important implications for the intrauterine programming of life expectancy.

  15. AOP description: Aromatase inhibition leading to reproductive dysfunction (in fish)

    EPA Science Inventory

    This adverse outcome pathway details the linkage between inhibition of gonadal aromatase activity in females and the adverse effect of reduced cumulative fecundity in repeat-spawning fish species. Cumulative fecundity is the most apical endpoint considered in the OECD 229 Fish Sh...

  16. Comment. The Comparative and Evolutionary Biology of Vertebrate Aromatase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aromatase is the enzyme responsible for the synthesis of estrogens from androgens. It is doubtful that there are many other genes that have such a broad and profound influence on reproduction and survival of species. The expression of this enzyme in various tissues controls both directly and indirec...

  17. Caught in a Network: Recovery from Aromatase Inhibition

    EPA Science Inventory

    Fadrozole is an inhibitor of aromatase, an enzyme critical to estrogen synthesis. We exposed female fathead minnows (Pimephales promelas, FHM) to 0 or 30 ug/L fadrozole for 8 days, and fish were then held in clean water for 8 extra days. We analyzed ex vivo steroid production, pl...

  18. Mechanisms of Aromatase Inhibitor-induced Musculoskeletal Symptoms

    DTIC Science & Technology

    2012-07-01

    neural physiology. For example, aromatase expression in the hippocampus protects hippocampal neurons against excitoxicity, which is thought to be a...Neuropharmacology 60, 580 (Mar, 2011). 32. I. H. Pang, M. R. Vasko, Morphine and norepinephrine but not 5-hydroxytryptamine and gamma- aminobutyric acid

  19. Quantitative AOP-based predictions for two aromatase ...

    EPA Pesticide Factsheets

    The adverse outcome pathway (AOP) framework can be used to support the use of mechanistic toxicology data as a basis for risk assessment. For certain risk contexts this includes defining, quantitative linkages between the molecular initiating event (MIE) and subsequent key events (KEs) within an AOP. One AOP for which strong, quantitative linkages have been established is aromatase inhibition leading to reproductive dysfunction in fish. A series of computational models have been linked to develop a quantitative AOP (Q-AOP). A measure of aromatase inhibition is used as the model input to estimate circulating plasma estradiol (E2) concentration and resultant circulating plasma vitellogenin (VTG) concentration. To evaluate model predictions, two aromatase inhibitors, letrozole and epoxiconazole, were selected based upon their relative aromatase inhibition potency in US EPA ToxCast assays. Reproductively mature female fathead minnows (Pimephales promelas) were exposed to varying concentrations of either letrozole (0.5, 7.5, 25, 75, 250 µg/L) or epoxiconazole (8, 25, 80, 250, 800 µg/L) in 24h flow through exposures. One additional consideration for model predictions was bioaccumulation of exposure chemicals and resultant circulating plasma concentration. To identify this, plasma from exposed minnows was extracted by supported liquid extraction (SLE) and concentrations of letrozole or epoxiconazole determined by LC-MS/MS. Plasma bioaccumulation factors (BAFplasma)

  20. Modulation of aromatase activity by diet polyphenolic compounds.

    PubMed

    Monteiro, Rosário; Azevedo, Isabel; Calhau, Conceição

    2006-05-17

    Estrogens are involved in physiological actions related to reproduction, body fat distribution, and maintenance of bone mass and are also related to the pathogenesis of estrogen-dependent cancers. The aim of this work was to study the effect of polyphenols on estrogen synthesis. The effect of polyphenols and polyphenolic-rich beverages on aromatase activity was tested in JAR cells (a choriocarcinoma cell line) through the tritiated water release assay. Some of the tested polyphenols inhibited estrogen production, chrysin being the most potent. Additionally, we observed that red wine, alcohol-free red wine, green tea, and black tea (200 microL/mL) significantly decreased aromatase activity. No effect on aromatase expression, as assessed by western blotting and RT-PCR, has been detected after 24 h of treatment with any of the flavonoids under study. In conclusion, polyphenols are able to modulate aromatase activity and, consequently, estrogen synthesis. The knowledge of such interference may help to clarify some of the biological properties attributed to polyphenols and may be useful in prevention/treatment of estrogen-dependent disorders.

  1. Time- and dose-dependent effects of roundup on human embryonic and placental cells.

    PubMed

    Benachour, N; Sipahutar, H; Moslemi, S; Gasnier, C; Travert, C; Séralini, G E

    2007-07-01

    Roundup is the major herbicide used worldwide, in particular on genetically modified plants that have been designed to tolerate it. We have tested the toxicity and endocrine disruption potential of Roundup (Bioforce on human embryonic 293 and placental-derived JEG3 cells, but also on normal human placenta and equine testis. The cell lines have proven to be suitable to estimate hormonal activity and toxicity of pollutants. The median lethal dose (LD(50)) of Roundup with embryonic cells is 0.3% within 1 h in serum-free medium, and it decreases to reach 0.06% (containing among other compounds 1.27 mM glyphosate) after 72 h in the presence of serum. In these conditions, the embryonic cells appear to be 2-4 times more sensitive than the placental ones. In all instances, Roundup (generally used in agriculture at 1-2%, i.e., with 21-42 mM glyphosate) is more efficient than its active ingredient, glyphosate, suggesting a synergistic effect provoked by the adjuvants present in Roundup. We demonstrated that serum-free cultures, even on a short-term basis (1 h), reveal the xenobiotic impacts that are visible 1-2 days later in serum. We also document at lower non-overtly toxic doses, from 0.01% (with 210 microM glyphosate) in 24 h, that Roundup is an aromatase disruptor. The direct inhibition is temperature-dependent and is confirmed in different tissues and species (cell lines from placenta or embryonic kidney, equine testicular, or human fresh placental extracts). Furthermore, glyphosate acts directly as a partial inactivator on microsomal aromatase, independently of its acidity, and in a dose-dependent manner. The cytotoxic, and potentially endocrine-disrupting effects of Roundup are thus amplified with time. Taken together, these data suggest that Roundup exposure may affect human reproduction and fetal development in case of contamination. Chemical mixtures in formulations appear to be underestimated regarding their toxic or hormonal impact.

  2. Intracellular Organisms as Placental Invaders

    PubMed Central

    Vigliani, Marguerite B.; Bakardjiev, Anna I.

    2015-01-01

    In this article we present a novel model for how the human placenta might get infected via the hematogenous route. We present a list of diverse placental pathogens, like Listeria monocytogenes or Cytomegalovirus, which are familiar to most obstetricians, but others, like Salmonella typhi, have only been reported in case studies or small case series. Remarkably, all of these organisms on this list are either obligate or facultative intracellular organisms. These pathogens are able to enter and survive inside host immune cells for at least a portion of their life cycle. We suggest that many blood-borne pathogens might arrive at the placenta via transportation inside of maternal leukocytes that enter the decidua in early pregnancy. We discuss mechanisms by which extravillous trophoblasts could get infected in the decidua and spread infection to other layers in the placenta. We hope to raise awareness among OB/GYN clinicians that organisms not typically associated with the TORCH list might cause placental infections and pregnancy complications. PMID:27695204

  3. Aromatase, estrogen receptors and brain development in fish and amphibians.

    PubMed

    Coumailleau, Pascal; Pellegrini, Elisabeth; Adrio, Fátima; Diotel, Nicolas; Cano-Nicolau, Joel; Nasri, Ahmed; Vaillant, Colette; Kah, Olivier

    2015-02-01

    Estrogens affect brain development of vertebrates, not only by impacting activity and morphology of existing circuits, but also by modulating embryonic and adult neurogenesis. The issue is complex as estrogens can not only originate from peripheral tissues, but also be locally produced within the brain itself due to local aromatization of androgens. In this respect, teleost fishes are quite unique because aromatase is expressed exclusively in radial glial cells, which represent pluripotent cells in the brain of all vertebrates. Expression of aromatase in the brain of fish is also strongly stimulated by estrogens and some androgens. This creates a very intriguing positive auto-regulatory loop leading to dramatic aromatase expression in sexually mature fish with elevated levels of circulating steroids. Looking at the effects of estrogens or anti-estrogens in the brain of adult zebrafish showed that estrogens inhibit rather than stimulate cell proliferation and newborn cell migration. The functional meaning of these observations is still unclear, but these data suggest that the brain of fish is experiencing constant remodeling under the influence of circulating steroids and brain-derived neurosteroids, possibly permitting a diversification of sexual strategies, notably hermaphroditism. Recent data in frogs indicate that aromatase expression is limited to neurons and do not concern radial glial cells. Thus, until now, there is no other example of vertebrates in which radial progenitors express aromatase. This raises the question of when and why these new features were gained and what are their adaptive benefits. This article is part of a Special Issue entitled: Nuclear receptors in animal development.

  4. Bisphenol A differentially activates protein kinase C isoforms in murine placental tissue

    SciTech Connect

    Tan, Wenjuan; Huang, Hui; Wang, Yanfei; Wong, Tsz Yan; Wang, C.C.; Leung, Lai K.

    2013-06-01

    Bisphenol A is utilized to make polycarbonate plastics and is an environmental pollutant. Recent research has indicated that it is an endocrine disruptor and may interfere with reproductive processes. Our lab has previously shown that bisphenol A could regulate corticotrophin releasing hormone and aromatase in cultured placental cells. In the present study, the effect of bisphenol A on these two genes in the placenta was investigated in mice. Pregnant ICR mice were gavaged with bisphenol A at 2, 20 and 200 mg/kg body weight/day from E13 to E16 and were euthanized at E17. Compared to the control mice, increased plasma estrogen and corticotrophin releasing hormone were observed in bisphenol A-treated mice. Messenger RNA quantification indicated that placental crh but not cyp19 was induced in mice treated with bisphenol A. Tracking the related signaling pathway, we found that protein kinase C ζ/λ and δ were activated in the placentas of bisphenol A-treated mice. As the gene promoter of crh contains CRE and the half site of ERE, either phospho-PKC or estrogen could stimulate the gene transactivation. These results indicate that bisphenol A might increase plasma concentrations of estradiol, testosterone, corticotrophin releasing hormone and placental phospho-PKC ζ/λ and δ in mice. Ultimately, the incidence of premature birth in these mice could increase. - Highlights: • The pollutant bisphenol A differentially activated PKC isoforms in the placenta. • CRE-binding activity in the nuclear protein of placenta was increased. • Bisphenol A induces CRH mRNA expression in mice.

  5. Parallel evolution between aromatase and androgen receptor in the animal kingdom.

    PubMed

    Tiwary, Basant; Tiwary, Besant K; Li, Wen-Hsiung

    2009-01-01

    There are now many known cases of orthologous or unrelated proteins in different species that have undergone parallel evolution to satisfy a similar function. However, there are no reported cases of parallel evolution for proteins that bind a common ligand but have different functions. We focused on two proteins that have different functions in steroid hormone biosynthesis and action but bind a common ligand, androgen. The first protein, androgen receptor (AR), is a nuclear hormone receptor and the second one, aromatase (cytochrome P450 19 [CYP19]), converts androgen to estrogen. We hypothesized that binding of the androgen ligand has exerted common selective pressure on both AR and CYP19, resulting in a signature of parallel evolution between these two proteins, though they perform different functions. Consistent with this hypothesis, we found that rates of amino acid change in AR and CYP19 are strongly correlated across the metazoan phylogeny, whereas no significant correlation was found in the control set of proteins. Moreover, we inferred that genomic toolkits required for steroid biosynthesis and action were present in a basal metazoan, cnidarians. The close similarities between vertebrate and sea anemone AR and CYP19 suggest a very ancient origin of their endocrine functions at the base of metazoan evolution. Finally, we found evidence supporting the hypothesis that the androgen-to-estrogen ratio determines the gonadal sex in all metazoans.

  6. Biological aromatization of delta4,6- and delta1,4,6-androgens and their 6-alkyl analogs, potent inhibitors of aromatase.

    PubMed

    Numazawa, M; Yoshimura, A

    1999-01-01

    Enzymic aromatization of delta6- and delta1,6-derivatives of the natural substrate androstenedione with human placental aromatase was first studied using gas-chromatography-mass spectrometry. The two steroids were aromatized with apparent Km and Vmax values of 62 nM and 32 pmol/min/mg protein for the delta6-steroid and 167 nM and 10 pmol/min/mg protein for the delta1,6-steroid, respectively. We next explored the aromatization of a series of 6-alkyl (methyl, ethyl, n-propyl, and n-pentyl)-substituted delta6-androstenediones and their delta1,6-analogs, potent competitive inhibitors of aromatase, to gain insight into the relationships between the inhibitory activity of the 6-alkyl-C19 steroids and their ability to serve as a substrate of aromatase. In a series of the delta1,6-androstenediones, all the 6-alkyl steroids were more efficient substrates than the parent delta1,6-steroid in which the aromatization rates of the alkyl steroids were about 2-fold that of the parent steroid, in contrast, all of the 6-alkyl-substituted delta6-androstenediones were converted into the corresponding 6-alkyl-delta6-estrogens with the rates of less than about a half that of the parent steroid. These results indicate that the 6-alkyl function decreases the aromatization rate of the delta6-steroid but enhances that of the delta1,6-steroid. The relative apparent Km values for the C19 steroids obtained in this study are different from the relative Ki values obtained previously, indicating that a good inhibitor is not essentially a good substrate in the 6-alkyl-substituted delta6- and delta1,6-androstenedione series.

  7. RELATIONSHIP BETWEEN BRAIN AND OVARY AROMATASE ACTIVITY AND ISOFORM-SPECIFIC AROMATASE MRNA EXPRESSION IN THE FATHEAD MINNOW (PIMEPHALES PROMELAS) - JOURNAL ARTICLE

    EPA Science Inventory

    There is growing evidence that some chemicals present in the environment have the capacity to inhibit, or potentially induce, aromatase activity. This study compared aromatase activities and isoform-specific mRNA expression in brain and ovary tissue from non-exposed fathead minn...

  8. Effect of hop (Humulus lupulus L.) flavonoids on aromatase (estrogen synthase) activity.

    PubMed

    Monteiro, Rosário; Becker, Hans; Azevedo, Isabel; Calhau, Conceiçáo

    2006-04-19

    The aim of this work was to study the effect of the prenylflavonoids xanthohumol, isoxanthohumol, and 8-prenylnaringenin on the activity and expression of the enzyme aromatase (estrogen synthase). The effect of different kinds of beer containing these prenylflavonoids was also tested. Aromatase activity was determined by measuring the release of tritiated water during the conversion of [(3)H]androstenedione to estrone. Aromatase expression was determined by RT-PCR. This assay was carried out in choriocarcinoma-derived JAR cells. The tested prenylflavonoids were able to inhibit estrogen formation, and their IC(50) values were determined, although no effect on aromatase expression was found. Lager beer, alcohol-free beer, stout beer, and xanthohumol-rich stout beer (200 microL/mL) significantly decreased aromatase activity. In conclusion, prenylflavonoids are able to modulate aromatase activity, decreasing estrogen synthesis, with relevance for the prevention and treatment of estrogen-dependent disorders such as breast cancer.

  9. Impact of Aromatase protein variants and drug interactions in breast cancer: a molecular docking approach.

    PubMed

    Setti, Aravind; Venugopal Rao, V; Priyamvada Devi, A; Pawar, Smita C; Naresh, B; Kalyan, C S V V

    2012-08-01

    Breast cancer is a frequently reported cancer in women all over the world. Several methods available to cure the breast cancer based on stage. This study focused on chemoprevention drugs of Aromatase, a potential target in breast cancer. Natural variants of Aromatase are very common; they have been collected and modeled, optimized the energy of mutated Aromatase protein. Reversible (Anastrozole) and irreversible (Exemestane) Aromatase inhibitors are selected and performed molecular docking studies of each drug against each variant to see the binding affinity impact on protein variant and drugs. In this comparative study, Anastrozole, a cumene derivative showed more binding affinity and Diethylstilbestrol showed weak binding affinity against among all drugs. The comparative molecular docking revealed that the binding affinity between drug and Aromatase protein variant is imprecise but fairly close; therefore the protein variants of Aromatase can be conceived to be equal for chemoprevention of breast cancer therapy.

  10. The evolution of epitheliochorial placentation.

    PubMed

    Carter, Anthony M; Enders, Allen C

    2013-01-01

    Epitheliochorial placentation is a derived condition and has evolved separately in strepsirrhine primates and laurasiatherians (pangolins, whales, and hoofed mammals). Usually it is associated with a long gestation period, small litters, and precocial young. Oxygen transfer is facilitated by indenting of the uterine and trophoblast epithelia by maternal and fetal capillaries, respectively. Histotrophic nutrition is important, and adaptations include areolas and hemophagous regions. In pigs and horses, for example, iron is transported as uteroferrin secreted from the uterine glands and taken up by areolas. In the horse, invasive trophoblast cells form cups within the endometrium that are the source of equine chorionic gonadotropin. In ruminants, binucleate trophoblast cells fuse with uterine epithelial cells to form trinucleate cells or plaques that secrete pregnancy hormones. There is evidence of immunosuppression in connection with these more invasive types of trophoblasts. The epitheliochorial condition may be advantageous for long pregnancies in large animals.

  11. Obesity and Postmenopausal Breast Cancer Risk: Determining the Role of Growth Factor-Induced Aromatase Expression

    DTIC Science & Technology

    2013-01-01

    aromatase inhibitor treatment. Obesity is accompanied by elevated levels of growth factors and inflammatory cytokines that can promote tumorigenesis and...whether the greater 8 ASC aromatase expression induced by exposure to Ob MCF-7 CM versus Con (Figure 7A) then results in greater estradiol ...ERE luciferase, when subjects that were on aromatase inhibitor treatment at the time of sera collection were eliminated from the Ob and Con sera

  12. Nelumal A, the active principle of Ligularia nelumbifolia, is a novel aromatase inhibitor.

    PubMed

    Epifano, Francesco; Genovese, Salvatore; Fiorito, Serena; Nde, Chantal Magne; Clyne, Colin

    2014-06-01

    Nelumal A, the active principle of Ligularia nelumbifolia was preliminarily tested as an aromatase inhibitors in HEK293 cells transfected with aromatase cDNA and using anastrazole as the reference drug. This screening revealed that it showed an appreciable level of inhibition. Subsequent experiments aimed to evaluate the aromatase activity and expression in KGN cells confirmed that the title natural product, after an incubation of 48 h, compared favourably with anastrazole (1 microM) in the concentration range 10-30 microM. Moreover, nelumal A (30 microM) abolished the aromatase mRNA expression in the same cell line.

  13. Sexing frogs by real-time PCR: using aromatase (cyp19) as an early ovarian differentiation marker.

    PubMed

    Navarro-Martín, L; Velasco-Santamaría, Y M; Duarte-Guterman, P; Robertson, C; Lanctôt, C; Pauli, B; Trudeau, V L

    2012-01-01

    Most anurans have no identified sex-markers; therefore, alternative methods for identification of early changes in sex ratios are required. In this study, Lithobates sylvaticus and Silurana tropicalis tadpoles were sampled at different developmental stages covering the entire process of sex differentiation. Three candidate genes known to be involved in sex differentiation in other vertebrate species were selected to develop a method to identify phenotypic sex in frogs: cytochrome p450 aromatase (cyp19), forkhead box L2 (foxl2) and the cytochrome 17-alpha-hydroxylase/17,20 lyase (cyp17). Cloning of these genes revealed nucleotide identity values ranging between 75-97% when compared to other amphibian species. Gene expression of cyp17,cyp19 and foxl2 in L. sylvaticus adult gonads and gonad-mesonephros complex (GMC) of tadpoles was analyzed by real-time RT-PCR. Results showed clear sexually dimorphic patterns in the expression of the 3 genes. Our analysis reveals that GMC gene expression levels of cyp19 alone can be used as a robust predictor of phenotypic sex in L. sylvaticus tadpoles. In addition, we validated this method measuring cyp19 mRNA levels in S. tropicalis GMCs. We propose measuring cyp19 as a tool to study the effects of chemical contaminants (including endocrine disrupting compounds) on amphibian gonadal development and sex ratios in the future.

  14. Placental immaturity, endocardial fibroelastosis and fetal hypoxia.

    PubMed

    Perez, Marie-Hélène; Boulos, Tatiana; Stucki, Pascal; Cotting, Jacques; Osterheld, Maria-Chiara; Di Bernardo, Stefano

    2009-01-01

    We describe a term newborn who, after a normal gestational course, presented at birth with absent cardiac activity and no spontaneous breathing. Death occurred within 30 h. Autopsy revealed placental villous immaturity, multiple acute hypoxic lesions, but also chronic hypoxic lesions like endocardial fibroelastosis. This striking association of endocardial fibroelastosis and placental villous immaturity is reviewed and correlated with 2 other cases of placental villous immaturity that led to in utero death at 39 and 41 weeks of gestation. Placental villous immaturity must be suspected and looked for by both pediatricians and obstetricians in every case of stillbirth or perinatal asphyxia of unclear origin. In order to minimize the risk of recurrence in further pregnancies, elective cesarean section may be considered.

  15. Comparative aspects of trophoblast development and placentation.

    PubMed

    Carter, Anthony M; Enders, Allen C

    2004-07-05

    Based on the number of tissues separating maternal from fetal blood, placentas are classified as epitheliochorial, endotheliochorial or hemochorial. We review the occurrence of these placental types in the various orders of eutherian mammals within the framework of the four superorders identified by the techniques of molecular phylogenetics. The superorder Afrotheria diversified in ancient Africa and its living representatives include elephants, sea cows, hyraxes, aardvark, elephant shrews and tenrecs. Xenarthra, comprising armadillos, anteaters and sloths, diversified in South America. All placentas examined from members of these two oldest superorders are either endotheliochorial or hemochorial. The superorder Euarchontoglires includes two sister groups, Glires and Euarchonta. The former comprises rodents and lagomorphs, which typically have hemochorial placentas. The most primitive members of Euarchonta, the tree shrews, have endotheliochorial placentation. Flying lemurs and all higher primates have hemochorial placentas. However, the lemurs and lorises are exceptional among primates in having epitheliochorial placentation. Laurasiatheria, the last superorder to arise, includes several orders with epitheliochorial placentation. These comprise whales, camels, pigs, ruminants, horses and pangolins. In contrast, nearly all carnivores have endotheliochorial placentation, whilst bats have endotheliochorial or hemochorial placentas. Also included in Laurasiatheria are a number of insectivores that have many conserved morphological characters; none of these has epitheliochorial placentation. Consideration of placental type in relation to the findings of molecular phylogenetics suggests that the likely path of evolution in Afrotheria was from endotheliochorial to hemochorial placentation. This is also a likely scenario for Xenarthra and the bats. We argue that a definitive epitheliochorial placenta is a secondary specialization and that it evolved twice, once in the

  16. Pharmacophore mapping of flavone derivatives for aromatase inhibition.

    PubMed

    Nagar, Shuchi; Islam, Md Ataul; Das, Suvadra; Mukherjee, Arup; Saha, Achintya

    2008-02-01

    Aromatase, which catalyses the final step in the steroidogenesis pathway of estrogen, has been target for the design of inhibitor in the treatment of hormone dependent breast cancer for postmenopausal women. The extensive SAR studies performed in the last 30 years to search for potent, selective and less toxic compounds, have led to the development of second and third generation of non-steroidal aromatase inhibitors (AI). Besides the development of synthetic compounds, several naturally occurring and synthetic flavonoids, which are ubiquitous natural phenolic compounds and mediate the host of biological activities, are found to demonstrate inhibitory effects on aromatase. The present study explores the pharmacophores, i.e., the structural requirements of flavones (Fig. 1) for inhibition of aromatase activity, using quantitative structure activity relationship (QSAR) and space modeling approaches. The classical QSAR studies generate the model (R (2) = 0.924, Q (2) = 0.895, s = 0.233) that shows the importance of aromatic rings A and C, along with substitutional requirements in meta and para positions of ring C for the activity. 3D QSAR of Comparative Molecular Field Analysis (CoMFA, R (2) = 0.996, R(2)(cv) = 0.791) and Comparative Molecular Similarity Analysis (CoMSIA, R (2) = 0.992, R(2)(cv) = 0.806) studies show contour maps of steric and hydrophobic properties and contribution of acceptor and donor of the molecule, suggesting the presence of steric hindrance due to ring C and R''-substituent, bulky hydrophobic substitution in ring A, along with acceptors at positions 11, and alpha and gamma of imidazole ring, and donor in ring C favor the inhibitory activity. Further space modeling (CATALYST) study (R = 0.941, Delta( cost ) = 96.96, rmsd = 0.876) adjudge the presence of hydrogen bond acceptor (keto functional group), hydrophobic (ring A) and aromatic rings (steric hindrance) along with critical distance among features are important for the inhibitory activity.

  17. The distinct proteome of placental malaria parasites.

    SciTech Connect

    Fried, Michal; Hixson, Kim K.; Anderson, Lori; Ogata, Yuko; Mutabingwa, Theonest K.; Duffy, Patrick E.

    2007-09-01

    Malaria proteins expressed on the surface of Plasmodium falciparum infected erythrocytes (IE) mediate adhesion and are targeted by protective immune responses. During pregnancy, IE sequester in the placenta. Placental IE bind to the molecule chondroitin sulfate A (CSA) and preferentially transcribe the gene that encodes VAR2CSA, a member of the PfEMP1 variant surface antigen family. Over successive pregnancies women develop specific immunity to CSA-binding IE and antibodies to VAR2CSA. We used tandem mass spectrometry together with accurate mass and time tag technology to study IE membrane fractions of placental parasites. VAR2CSA peptides were detected in placental IE and in IE from children, but the MC variant of VAR2CSA was specifically associated with placental IE. We identified six conserved hypothetical proteins with putative TM or signal peptides that were exclusively expressed by the placental IE, and 11 such proteins that were significantly more abundant in placental IE. One of these hypothetical proteins, PFI1785w, is a 42kDa molecule detected by Western blot in parasites infecting pregnant women but not those infecting children.

  18. Effect of dioxin exposure on aromatase expression in ovariectomized rats.

    PubMed

    Ye, Lan; Leung, Lai K

    2008-05-15

    Because of their persistence in the environment dioxins are one of the most concerned classes of carcinogens. Displaying both pro- and anti-agonistic properties to some hormone receptors, the pollutants are also known to be endocrine disruptors. Humans can be exposed to this pollutant through contaminated food, air, drinking water, etc. The female hormone estrogen may initiate various physiological functions, and excessive exposure to this hormone is a documented risk factor for carcinogenesis. Cyp19 (aromatase) catalyses the last step of estrogen biosynthesis, while cyp1a1 can hydroxylate and deactivate the hormone. In the present study, we investigated the effect of 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD) on aromatase expression in the brain and adipose tissue in ovariectomized Sprague Dawley rats. Female rats were given 2.5 microg/kg TCDD p.o. before and after ovariectomy. Real-time PCR and western blot analysis indicated that pre-ovariectomy administration of TCDD could significantly reduce aromatase expression in the brain but increase the expression in the adipose tissue. In addition, increased plasma estrogen level and uterine weight were observed in these rats. These parameters did not change in rats with post-ovariectomy TCDD treatment. Our results suggested that the timing of exposure to the toxicant could determine the estrogenicity of TCDD. No correlation between cyp1a1 and cyp19 expression was observed.

  19. Effect of dioxin exposure on aromatase expression in ovariectomized rats

    SciTech Connect

    Ye Lan; Leung, Lai K.

    2008-05-15

    Because of their persistence in the environment dioxins are one of the most concerned classes of carcinogens. Displaying both pro- and anti-agonistic properties to some hormone receptors, the pollutants are also known to be endocrine disruptors. Humans can be exposed to this pollutant through contaminated food, air, drinking water, etc. The female hormone estrogen may initiate various physiological functions, and excessive exposure to this hormone is a documented risk factor for carcinogenesis. Cyp19 (aromatase) catalyses the last step of estrogen biosynthesis, while cyp1a1 can hydroxylate and deactivate the hormone. In the present study, we investigated the effect of 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD) on aromatase expression in the brain and adipose tissue in ovariectomized Sprague Dawley rats. Female rats were given 2.5 {mu}g/kg TCDD p.o. before and after ovariectomy. Real-time PCR and western blot analysis indicated that pre-ovariectomy administration of TCDD could significantly reduce aromatase expression in the brain but increase the expression in the adipose tissue. In addition, increased plasma estrogen level and uterine weight were observed in these rats. These parameters did not change in rats with post-ovariectomy TCDD treatment. Our results suggested that the timing of exposure to the toxicant could determine the estrogenicity of TCDD. No correlation between cyp1a1 and cyp19 expression was observed.

  20. Modulation of Aromatase Activity as a Mode of Action for Endocrine Disrupting Chemicals in a Marine Fish

    EPA Science Inventory

    The steroidogenic enzyme aromatase catalyzes the conversion of androgens (androstenedione and testosterone) to estrogens (estrone and estradiol) and therefore plays a central role in reproduction. In contrast to most vertebrates, teleost fish have two distinct forms of aromatase....

  1. Computational Modeling to Evaluate Alternative Hypotheses for the Linkage of Aromatase Inhibition to Vitellogenin Levels in Fathead Minnows

    EPA Science Inventory

    Aromatase converts testosterone to estradiol (E2). In fish, E2 concentrations control hepatic synthesis of the glycolipoprotein vitellogenin (VTG), an egg yolk precursor protein essential to oocyte development and larval survival. Fathead minnows were exposed to the aromatase in...

  2. Modulation of aromatase activity as a mode of action for endocrine disrupting chemicals in a marine fish.

    PubMed

    Mills, Lesley J; Gutjahr-Gobell, Ruth E; Zaroogian, Gerald E; Horowitz, Doranne Borsay; Laws, Susan C

    2014-02-01

    The steroidogenic enzyme aromatase catalyzes the conversion of androgens to estrogens and therefore plays a central role in reproduction. In contrast to most vertebrates, teleost fish have two distinct forms of aromatase. Because brain aromatase activity in fish is up to 1000 times that in mammals, fish may be especially susceptible to negative effects from environmental endocrine-disrupting chemicals (EDCs) that impact aromatase activity. In this study, the effects of estradiol (E2), ethynylestradiol (EE2), octylphenol (OP), and androstatrienedione (ATD) on reproduction and aromatase activity in brains and gonads from the marine fish cunner (Tautogolabrus adspersus) was investigated. The purpose of the study was to explore the relationship between changes in aromatase activity and reproductive output in a marine fish, as well as compare aromatase activity to two commonly used indicators of EDC exposure, plasma vitellogenin (VTG) and gonadosomatic index (GSI). Results with E2, EE2, and ATD indicate that aromatase activity in cunner brain and ovary are affected differently by exposure to these EDCs. In the case of E2 and EE2, male brain aromatase activity was signficantly increased by these treatments, female brain aromatase activity was unaffected, and ovarian aromatase activity was significantly decreased. Treatment with the aromatase inhibitor ATD resulted in significantly decreased aromatase activity in male and female brain, but had no significant impact on ovarian aromatase activity. Regardless of test chemical, a decrease or an increase in male brain aromatase activity relative to controls was associated with decreased egg production in cunner and was also correlated with significant changes in GSI in both sexes. E2 and EE2 significantly elevated plasma VTG in males and females, while ATD had no significant effect. Treatment of cunner with OP had no significant effect on any measured endpoint. Overall, results with these exposures indicate EDCs that impact

  3. Impaired placentation in fetal alcohol syndrome.

    PubMed

    Gundogan, F; Elwood, G; Longato, L; Tong, M; Feijoo, A; Carlson, R I; Wands, J R; de la Monte, S M

    2008-02-01

    Intrauterine growth restriction (IUGR) is one of the key features of fetal alcohol syndrome (FAS), and IUGR can be mediated by impaired placentation. Insulin-like growth factors (IGF) regulate placentation due to stimulatory effects on extravillous trophoblasts, which are highly motile and invasive. Previous studies demonstrated that extravillous trophoblasts express high levels of aspartyl-(asparaginyl) beta-hydroxylase (AAH), a gene that is regulated by IGF and has a critical role in cell motility and invasion. The present study examines the hypothesis that ethanol impaired placentation is associated with inhibition of AAH expression in trophoblasts. Pregnant Long Evans rats were fed isocaloric liquid diets containing 0% or 37% ethanol by caloric content. Placentas harvested on gestation day 16 were used for histopathological, mRNA, and protein studies to examine AAH expression in relation to the integrity of placentation and ethanol exposure. Chronic ethanol feeding prevented or impaired the physiological conversion of uterine vessels required for expansion of maternal circulation into placenta, a crucial process for adequate placentation. Real-time quantitative RT-PCR analysis demonstrated significant reductions in IRS-1, IRS-2, and significant increases in IGF-II and IGF-II receptor mRNA levels in ethanol-exposed placentas. These abnormalities were associated with significantly reduced levels of AAH expression in trophoblastic cells, particularly within the mesometrial triangle (deep placental bed) as demonstrated by real time quantitative RT-PCR, Western blot analysis, ELISA, and immunohistochemical staining. Ethanol-impaired placentation is associated with inhibition of AAH expression in trophoblasts. This effect of chronic gestational exposure to ethanol may contribute to IUGR in FAS.

  4. Mosaic retroposon insertion patterns in placental mammals.

    PubMed

    Churakov, Gennady; Kriegs, Jan Ole; Baertsch, Robert; Zemann, Anja; Brosius, Jürgen; Schmitz, Jürgen

    2009-05-01

    One and a half centuries after Charles Darwin and Alfred Russel Wallace outlined our current understanding of evolution, a new scientific era is dawning that enables direct observations of genetic variation. However, pure sequence-based molecular attempts to resolve the basal origin of placental mammals have so far resulted only in apparently conflicting hypotheses. By contrast, in the mammalian genomes where they were highly active, the insertion of retroelements and their comparative insertion patterns constitute a neutral, virtually homoplasy-free archive of evolutionary histories. The "presence" of a retroelement at an orthologous genomic position in two species indicates their common ancestry in contrast to its "absence" in more distant species. To resolve the placental origin controversy we extracted approximately 2 million potentially phylogenetically informative, retroposon-containing loci from representatives of the major placental mammalian lineages and found highly significant evidence challenging all current single hypotheses of their basal origin. The Exafroplacentalia hypothesis (Afrotheria as the sister group to all remaining placentals) is significantly supported by five retroposon insertions, the Epitheria hypothesis (Xenarthra as the sister group to all remaining placentals) by nine insertion patterns, and the Atlantogenata hypothesis (a monophyletic clade comprising Xenarthra and Afrotheria as the sister group to Boreotheria comprising all remaining placentals) by eight insertion patterns. These findings provide significant support for a "soft" polytomy of the major mammalian clades. Ancestral successive hybridization events and/or incomplete lineage sorting associated with short speciation intervals are viable explanations for the mosaic retroposon insertion patterns of recent placental mammals and for the futile search for a clear root dichotomy.

  5. Mosaic retroposon insertion patterns in placental mammals

    PubMed Central

    Churakov, Gennady; Kriegs, Jan Ole; Baertsch, Robert; Zemann, Anja; Brosius, Jürgen; Schmitz, Jürgen

    2009-01-01

    One and a half centuries after Charles Darwin and Alfred Russel Wallace outlined our current understanding of evolution, a new scientific era is dawning that enables direct observations of genetic variation. However, pure sequence-based molecular attempts to resolve the basal origin of placental mammals have so far resulted only in apparently conflicting hypotheses. By contrast, in the mammalian genomes where they were highly active, the insertion of retroelements and their comparative insertion patterns constitute a neutral, virtually homoplasy-free archive of evolutionary histories. The “presence” of a retroelement at an orthologous genomic position in two species indicates their common ancestry in contrast to its “absence” in more distant species. To resolve the placental origin controversy we extracted ∼2 million potentially phylogenetically informative, retroposon-containing loci from representatives of the major placental mammalian lineages and found highly significant evidence challenging all current single hypotheses of their basal origin. The Exafroplacentalia hypothesis (Afrotheria as the sister group to all remaining placentals) is significantly supported by five retroposon insertions, the Epitheria hypothesis (Xenarthra as the sister group to all remaining placentals) by nine insertion patterns, and the Atlantogenata hypothesis (a monophyletic clade comprising Xenarthra and Afrotheria as the sister group to Boreotheria comprising all remaining placentals) by eight insertion patterns. These findings provide significant support for a “soft” polytomy of the major mammalian clades. Ancestral successive hybridization events and/or incomplete lineage sorting associated with short speciation intervals are viable explanations for the mosaic retroposon insertion patterns of recent placental mammals and for the futile search for a clear root dichotomy. PMID:19261842

  6. Aromatization of 7 alpha-methyl-19-nortestosterone by human placental microsomes in vitro.

    PubMed

    LaMorte, A; Kumar, N; Bardin, C W; Sundaram, K

    1994-02-01

    Part of the biological effects of testosterone (T) are mediated by its enzymatic reduction to 5 alpha-dihydrotestosterone (DHT) or aromatization to estradiol (E2). 7 alpha-Methyl-19-nortestosterone (MENT) is a synthetic androgen that is considerably more potent than T. Previous studies have shown that MENT is not 5 alpha-reduced. The studies reported here were undertaken to determine whether MENT undergoes enzymatic aromatization in vitro. Human placental microsomes were used as the source of the aromatase. Radioactive or nonradioactive T or MENT was incubated with the microsomes in the presence of NADPH and the metabolites extracted out with ethyl ether. Following evaporation of ether, the residue was dissolved in benzene-petroleum ether and extracted with 0.4 N NaOH which selectively removes phenolic metabolites of the androgens. When either radioactive T or MENT was incubated with the aromatase in the presence of NADPH, there was a 20-fold increase in the amount of radioactivity extracted with NaOH. In contrast, if the incubation was carried out in the absence of NADPH or in the presence of R76713, an aromatase inhibitor, most of the radioactivity remained in the benzene-petroleum ether phase. To further identify the enzymatic reaction products, thin layer chromatography (TLC) was performed. The Rf value for MENT was 0.22 while that of the major reaction product was 0.34, which corresponded with the RF value of the estrogen, 7 alpha-methyl-estradiol (MeE2). This was further verified by using a second solvent system for the chromatographic separation. In an effort to ascertain whether the metabolites bind to estrogen receptors (ER), rat uterine cytosol was used. NaOH extracts of medium following incubation of nonradioactive MENT with microsomes showed competitive inhibition of [3H]E2 binding to rat uterine ER. Furthermore, after [3H]MENT was incubated with microsomes, the radioactive metabolite extracted in NaOH showed specific binding to the ER which could

  7. Micro-RNA378 (miR-378) regulates ovarian estradiol production by targeting aromatase.

    PubMed

    Xu, Shengyu; Linher-Melville, Katja; Yang, Burton B; Wu, De; Li, Julang

    2011-10-01

    Estradiol is a steroid hormone that not only plays an important role in ovarian follicular development but also is associated with many reproductive disorders. Owing to the importance of aromatase in the production of estradiol, the regulation of aromatase gene expression at the transcriptional level has been an extensive area of study for over two decades. However, its regulation at the posttranscriptional level has remained unclear. Here, we show that micro-RNA378 (miR-378) is spatiotemporally expressed in porcine granulosa cells, the cells that generate estradiol in the ovary during follicular development, in an inverse manner compared with the expression of aromatase. In vitro overexpression and inhibition experiments revealed that aromatase expression, and therefore estradiol production, by granulosa cells, is posttranscriptionally down-regulated by miR-378. Furthermore, site-directed mutation studies identified two binding sites in the 3'-untranslated region (3'-UTR) of the aromatase coding sequence that are critical for the action of miR-378. Interestingly, overexpression of the aromatase 3'-UTR enhanced aromatase expression at the protein level in granulosa cells, possibly mediated by the binding of miR-378 within this region, thereby reducing the binding of this micro-RNA to the endogenous aromatase 3'-UTR.

  8. Aromatase Expression in the Hippocampus of AD Patients and 5xFAD Mice

    PubMed Central

    Prange-Kiel, Janine; Dudzinski, Danuta A.; Pröls, Felicitas; Glatzel, Markus; Matschke, Jakob; Rune, Gabriele M.

    2016-01-01

    Numerous studies show that 17β-estradiol (E2) protects against Alzheimer's disease (AD) induced neurodegeneration. The E2-synthesizing enzyme aromatase is expressed in healthy hippocampi, but although the hippocampus is severely affected in AD, little is known about the expression of hippocampal aromatase in AD. To better understand the role of hippocampal aromatase in AD, we studied its expression in postmortem material from patients with AD and in a mouse model for AD (5xFAD mice). In human hippocampi, aromatase-immunoreactivity was observed in the vast majority of principal neurons and signal quantification revealed higher expression of aromatase protein in AD patients compared to age- and sex-matched controls. The tissue-specific first exons of aromatase I.f, PII, I.3, and I.6 were detected in hippocampi of controls and AD patients by RT-PCR. In contrast, 3-month-old, female 5xFAD mice showed lower expression of aromatase mRNA and protein (measured by qRT-PCR and semiquantitative immunohistochemistry) than WT controls; no such differences were observed in male mice. Our findings stress the importance of hippocampal aromatase expression in neurodegenerative diseases. PMID:27298742

  9. Aromatase inhibition 2013: clinical state of the art and questions that remain to be solved

    PubMed Central

    Lønning, Per Eystein; Eikesdal, Hans Petter

    2013-01-01

    Following their successful implementation for the treatment of metastatic breast cancer, the ‘third-generation’ aromatase inhibitors (anastrozole, letrozole, and exemestane) have now become standard adjuvant endocrine treatment for postmenopausal estrogen receptor-positive breast cancers. These drugs are characterized by potent aromatase inhibition, causing >98% inhibition of estrogen synthesis in vivo. A recent meta-analysis found no difference in anti-tumor efficacy between these three compounds. As of today, aromatase inhibitor monotherapy and sequential treatment using tamoxifen followed by an aromatase inhibitor for a total of 5 years are considered equipotent treatment options. However, current trials are addressing the potential benefit of extending treatment duration beyond 5 years. Regarding side effects, aromatase inhibitors are not found associated with enhanced risk of cardiovascular disease, and enhanced bone loss is prevented by adding bisphosphonates in concert for those at danger of developing osteoporosis. However, arthralgia and carpal tunnel syndrome preclude drug administration among a few patients. While recent findings have questioned the use of aromatase inhibitors among overweight and, in particular, obese patients, this problem seems to focus on premenopausal patients treated with an aromatase inhibitor and an LH-RH analog in concert, questioning the efficacy of LH-RH analogs rather than aromatase inhibitors among overweight patients. Finally, recent findings revealing a benefit from adding the mTOR inhibitor everolimus to endocrine treatment indicate targeted therapy against defined growth factor pathways to be a way forward, by reversing acquired resistance to endocrine therapy. PMID:23625614

  10. Potential utility of natural products as regulators of breast cancer-assoicated aromatase promoters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aromatase, the key enzyme in estrogen biosynthesis, converts androstenedione to estrone and testosterone to estradiol. The enzyme is expressed in various tissues such as ovary, placenta, bone, brain, skin, and adipose tissue. Aromatase enzyme is encoded by a single gene CYP 19A1 and its expression i...

  11. Induction of CYP1A and cyp2-mediated arachidonic acid epoxygenation and suppression of 20-hydroxyeicosatetraenoic acid by imidazole derivatives including the aromatase inhibitor vorozole.

    PubMed

    Diani-Moore, Silvia; Papachristou, Fotini; Labitzke, Erin; Rifkind, Arleen B

    2006-08-01

    Cytochrome P450 (P450) enzymes metabolize the membrane lipid arachidonic acid to stable biologically active epoxides [eicosatrienoic acids (EETs)] and 20-hydroxyeicosatetraenoic acid (20-HETE). These products have cardiovascular activity, primarily acting as vasodilators and vasoconstrictors, respectively. EET formation can be increased by the prototype CYP1A or CYP2 inducers, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or phenobarbital (PB), respectively. We report here that imidazole derivative drugs: the anthelminthics, albendazole and thiabendazole; the proton pump inhibitor, omeprazole; the thromboxane synthase inhibitor, benzylimidazole; and the aromatase (CYP19) inhibitor vorozole (R76713, racemate; and R83842, (+) enantiomer) increased hepatic microsomal EET formation in a chick embryo model. Albendazole increased EETs by transcriptional induction of CYP1A5 and the others by combined induction of CYP1A5 and CYP2H, the avian orthologs of mammalian CYP1A2 and CYP2B, respectively. All inducers increased formation of the four EET regioisomers, but TCDD and albendazole had preference for 5,6-EET and PB and omeprazole for 14,15-EET. Vorozole, benzylimidazole, and TCDD also suppressed 20-HETE formation. Vorozole was a remarkably effective and potent inducer of multiple hepatic P450s at a dose range which overlapped its inhibition of ovarian aromatase. Increased CYP1A activity in mouse Hepa 1-6 and human HepG2 cells by vorozole and other imidazole derivatives demonstrated applicability of the findings to mammalian cells. The findings suggest that changes in P450-dependent arachidonic acid metabolism may be a new source of side effects for drugs that induce CYP1A or CYP2. They demonstrate further that in vivo induction of multiple hepatic P450s produces additive increases in arachidonic acid epoxygenase activity and can occur concurrently with inhibition of ovarian aromatase activity.

  12. The expression of aromatase in gonadotropes is regulated by estradiol and gonadotropin-releasing hormone in a manner that differs from the regulation of luteinizing hormone.

    PubMed

    Galmiche, Guillaume; Richard, Nicolas; Corvaisier, Sophie; Kottler, Marie-Laure

    2006-09-01

    The role of estrogens is dual: they suppress basal expression of gonadotropins and enhance GnRH responsiveness at the time of the LH surge. Estrogens are synthesized by cytochrome P450 aromatase (P450arom), encoded by the cyp19 gene. We focused on the cyp19 gene in rat and showed that it is expressed in gonadotropes through promoters PII and PI.f, using RT-PCR and dual fluorescence labeling with anti-P450arom and -LH antibodies. Real-time PCR quantification revealed that aromatase mRNA levels varied during the estrous cycle and were significantly increased after ovariectomy. This effect is prevented by estradiol (E2) as well as GnRH antagonist administration, suggesting that GnRH may mediate the steroid effect. Interestingly, the long-acting GnRH agonist that induces LH desensitization does not modify aromatase expression in ovariectomized rats. Administration of E2 in ovariectomized rats receiving either GnRH agonist or GnRH antagonist clearly demonstrated that E2 also reduces cyp19 expression at the pituitary level. The selective estrogen receptor-alpha ligand propyl pyrazole triol and the selective estrogen receptor-beta ligand diarylpropionitrile both mimic the E2 effects. By contrast, propyl pyrazole triol reduces LH beta expression whereas diarylpropionitrile does not. In addition, using transient transfection assays in an L beta T2 gonadotrope cell line, we provided evidence that GnRH agonist stimulated, in a dose-dependant manner, cyp19 promoters PII and PI.f and that E2 decreased the GnRH stimulation. In conclusion, our data demonstrate that GnRH is an important signal in the regulation of cyp19 in gonadotrope cells. Both common and specific intracellular factors were responsible for dissociated variations of LH beta and cyp19 expression.

  13. A quality system for placental blood banking.

    PubMed

    Sirchia, G; Rebulla, P; Mozzi, F; Lecchi, L; Lazzari, L; Ratti, I

    1998-06-01

    A Quality System for Placental Blood Banking aimed at the transplantation of haematopoietic stem cells to related and unrelated allogeneic recipients is described. It includes the organizational structure, procedures, processes and resources needed to implement quality management. The Quality System described in this article is based on ISO 9002, a model for quality assurance in production, installation and servicing developed in 1987 and revised in 1994 by the International Organization for Standardization. ISO 9002 includes 20 clauses that provide guidance for the implementation of the Quality System. The development of the Quality System is started by the Placental Blood Bank Medical Director with the definition of a General Quality Plan including: (1) the written description of the Mission, Objectives, Technical and Organizational Policies, and Staff Organization Chart; (2) the definition and acquisition of adequate financial, human and structural resources; (3) the appointment of a Quality System Head, who must identify the Placental Blood Banking process together with the Placental Blood Bank personnel; implement a documentation plan; identify quality indicators; start regular internal audit; report audit results to the Medical Director for review. Following staff training and qualification, the Quality System is launched. The Placental Blood Bank can then undergo audit by an external inspector and be finally certified for compliance to ISO 9002. The Quality System must be maintained and subjected to external audit at regular intervals so that certification is confirmed.

  14. Optimization of the aromatase inhibitory activities of pyridylthiazole analogues of resveratrol.

    PubMed

    Mayhoub, Abdelrahman S; Marler, Laura; Kondratyuk, Tamara P; Park, Eun-Jung; Pezzuto, John M; Cushman, Mark

    2012-04-01

    Aromatase is an established target not only for breast cancer chemotherapy, but also for breast cancer chemoprevention. The moderate and non-selective aromatase inhibitory activity of resveratrol (1) was improved about 100-fold by replacement of the ethylenic bridge with a thiadiazole and the phenyl rings with pyridines (e.g., compound 3). The aromatase inhibitory activity was enhanced over 6000-fold by using a 1,3-thiazole as the central ring and modifying the substituents on the 'A' ring to target the Met374 residue of aromatase. On the other hand, targeting the hydroxyl group of Thr310 by a hydrogen-bond acceptor on the 'B' ring did not improve the aromatase inhibitory activity.

  15. Design, synthesis, and 3D QSAR of novel potent and selective aromatase inhibitors.

    PubMed

    Leonetti, Francesco; Favia, Angelo; Rao, Angela; Aliano, Rosaria; Paluszcak, Anja; Hartmann, Rolf W; Carotti, Angelo

    2004-12-30

    The design, synthesis, and biological evaluation of a series of new aromatase inhibitors bearing an imidazole or triazole ring linked to a fluorene (A), indenodiazine (B), or coumarin scaffold (C) are reported. Properly substituted coumarin derivatives displayed the highest aromatase inhibitory potency and selectivity over 17-alpha-hydroxylase/17-20 lyase. The modeling of the aromatase inhibition data by Comparative Molecular Field Analysis (CoMFA/GOLPE 3D QSAR approach) led to the development of a PLS model with good fitting and predictive powers (n = 22, ONC = 3, r(2) = 0.949, s = 0.216, and q(2) = 0.715). The relationship between aromatase inhibition and the steric and electrostatic fields generated by the examined azole inhibitors enables a clear understanding of the nature and spatial location of the main interactions modulating the aromatase inhibitory potency.

  16. Nicotine Blocks Brain Estrogen Synthase (Aromatase): In Vivo Positron Emission Tomography Studies in Female Baboons

    SciTech Connect

    Biegon, A.; Biegon, A.; Kim, S.-W.; Logan, J.; Hooker, J.M.; Muench, L.; Fowler, J.S.

    2010-01-12

    Cigarette smoking and nicotine have complex effects on human physiology and behavior, including some effects similar to those elicited by inhibition of aromatase, the last enzyme in estrogen biosynthesis. We report the first in vivo primate study to determine whether there is a direct effect of nicotine administration on brain aromatase. Brain aromatase availability was examined with positron emission tomography and the selective aromatase inhibitor [{sup 11}C]vorozole in six baboons before and after exposure to IV nicotine at .015 and .03 mg/kg. Nicotine administration produced significant, dose-dependent reductions in [{sup 11}C]vorozole binding. The amygdala and preoptic area showed the largest reductions. Plasma levels of nicotine and its major metabolite cotinine were similar to those found in cigarette smokers. Nicotine interacts in vivo with primate brain aromatase in regions involved in mood, aggression, and sexual behavior.

  17. Facile synthesis of chrysin-derivatives with promising activities as aromatase inhibitors.

    PubMed

    Mohammed, Hamdoon A; Ba, Lalla A; Burkholz, Torsten; Schumann, Elena; Diesel, Britta; Zapp, Josef; Kiemer, Alexandra K; Ries, Christina; Hartmann, Rolf W; Hosny, Mohammed; Jacob, Claus

    2011-01-01

    Flavones such as chrysin show structural similarities to androgens, the substrates of human aromatase, which converts androgens to estrogens. Aromatase is a key target in the treatment of hormone-dependent tumors, including breast cancer. Flavone-based aromatase inhibitors are of growing interest, and chrysin in particular provides a (natural) lead structure. This paper reports multicomponent synthesis as a means for facile modification of the chrysin core structure in order to add functional elements. A Mannich-type reaction was used to synthesize a range of mono- and disubstituted chrysin derivatives, some of which are more effective aromatase inhibitors than the benchmark compound, aminoglutethimide. Similarly, the reaction of chrysin with various isonitriles and acetylene dicarboxylates results in a new class of flavone derivatives, tricyclic pyrano-flavones which also inhibit human aromatase. Multicomponent reactions involving flavones therefore enable the synthesis of a variety of derivatives, some of which may be useful as anticancer agents.

  18. Developing steroidal aromatase inhibitors-an effective armament to win the battle against breast cancer.

    PubMed

    Yadav, Mange Ram; Barmade, Mahesh A; Tamboli, Riyaj S; Murumkar, Prashant R

    2015-11-13

    Breast cancer, an emerging disease among the women population, occurs due to overexpression of estrogens. The enzyme aromatase plays a key rate limiting role in the biosynthesis of estrogens. Certain clinical advantages of the use of exemestane, a steroidal aromatase inhibitor over non-steroidal aromatase inhibitors have drawn the attention of researchers for the development of novel steroidal aromatase inhibitors.The current review is a humble attempt to compile the reports by various researchers till date on the synthesis of steroidal aromatase inhibitors. It has been tried to encompass the structural modifications carried out by various researchers in the steroid ring system by taking up the functional group modifications on rings A, B, ring A/B junction, ring-D, ring modifications, bridged derivatives and heterocyclic ring-fused derivatives in a systematic way.

  19. Effect of the aromatase inhibitor CGS-16949A on pregnancy and secretion of progesterone, estradiol-17beta, prostaglandins E and F2alpha (PGE; PGF2alpha) and pregnancy specific protein B (PSPB) in 90-day ovariectomized pregnant ewes.

    PubMed

    Weems, Y S; Bridges, P J; LeaMaster, B R; Sasser, R G; Ching, L; Weems, C W

    2001-09-01

    The aromatase inhibitor CGS-16949A was used to determine whether CGS-16949A altered secretion of progesterone, estradiol-17beta, PGE (PGE1 + PGE2), PGF2alpha and PSPB. Ninety day pregnant ewes were ovariectomized and received vehicle, PGF2alpha, CGS-16949A or PGF2alpha+CGS-16949A. None of the ewes treated with PGF2alpha, CGS-16949A or PGF2alpha+CGS-16949A aborted (P > or = 0.05) during the 108-h experimental period. Treatment with CGS-16949A lowered (P < or = 0.05) progesterone in jugular venous plasma but concentrations of progesterone were not affected (P > or = 0.05) by treatment with PGF2alpha. Concentrations of estradiol-17beta and PSPB in jugular venous plasma and PGE in inferior vena cava plasma were decreased (P < or = 0.05) by treatment with CGS-16949A. Concentrations of PGF2alpha in inferior vena cava plasma were not affected (P > or = 0.05) by treatment with CGS-16949A. Decreases in estradiol-17beta occurred before decreases in PSPB, which was then followed by decreases in PGE (P < or = 0.05). It is concluded that these data support the hypothesis that estradiol-17beta regulates placental secretion of PSPB; PSPB regulates placental secretion of PGE; and PGE regulates placental secretion of progesterone during mid-pregnancy in ewes.

  20. 21 CFR 862.1585 - Human placental lactogen test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... placental lactogen are used in the diagnosis and clinical management of high-risk pregnancies involving fetal distress associated with placental insufficiency. Measurements of HPL are also used in...

  1. 21 CFR 862.1585 - Human placental lactogen test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... placental lactogen are used in the diagnosis and clinical management of high-risk pregnancies involving fetal distress associated with placental insufficiency. Measurements of HPL are also used in...

  2. Aromatase enzyme expression in acromegaly and its possible relationship with disease prognosis.

    PubMed

    Selek, Alev; Cetinarslan, Berrin; Gurbuz, Yesim; Tarkun, Ilhan; Canturk, Zeynep; Cabuk, Burak

    2015-05-01

    The purpose of this study was to evaluate aromatase enzyme expression in growth hormone (GH) secreting adenomas and comparison with prolactinomas, nonfunctional adenomas, and normal pituitary tissues. Also the impact of its expression on clinical and prognostic features was evaluated. 38 acromegaly, 26 prolactinoma, and 31 nonfunctional pituitary adenoma and 11 normal pituitary gland samples from autopsies were included. Aromatase and estrogen receptor-alpha (ERα) were evaluated by Immunohistochemical method; demographic, pre- and postoperative features of the patients were noted. Aromatase was expressed in varying degrees in all cases in study including controls. Aromatase expression in patients with acromegaly was significantly higher than patients with prolactinoma, nonfunctional adenoma, and controls (p = 0.04, p = 0.01 and p < 0.001, respectively). Taken together two functional adenoma groups, prolactinoma and acromegaly, aromatase expression was negatively correlated with ER-alpha (p = 0.02, r = -0.34). Also, Ki-67 immunohistochemical results were negatively correlated with aromatase expression (p = 0.03, r = -0.27) while positively correlated with ER expression (p < 0.01). Consistent with the growing evidence about testosterone effect on pituitary functions, aromatase expression was found to be higher in GH-secreting pituitary adenoma. Aromatase was expressed in all pituitary tissues including autopsy samples; however, it was highest in patients with acromegaly. In patients with acromegaly and prolactinoma, aromatase expression was negatively correlated with Ki-67 score, and also it was higher in patients with complete postoperative remission than without remission. Therefore, aromatase expression may be a good prognostic marker predominantly in acromegaly.

  3. Placental genetic variations in circadian clock-related genes increase the risk of placental abruption

    PubMed Central

    Qiu, Chunfang; Gelaye, Bizu; Denis, Marie; Tadesse, Mahlet G; Enquobahrie, Daniel A; Ananth, Cande V; Pacora, Percy N; Salazar, Manuel; Sanchez, Sixto E; Williams, Michelle A

    2016-01-01

    The genetic architecture of placental abruption (PA) remains poorly understood. We examined variations in SNPs of circadian clock-related genes in placenta with PA risk. We also explored placental and maternal genomic contributions to PA risk. Placental genomic DNA samples were isolated from 280 PA cases and 244 controls. Genotyping was performed using the Illumina Cardio-MetaboChip. We examined 116 SNPs in 13 genes known to moderate circadian rhythms. Logistic regression models were fit to estimate odds ratios (ORs). The combined effect of multiple SNPs on PA risk was estimated using a weighted genetic risk score. We examined independent and joint associations of wGRS derived from placental and maternal genomes with PA. Seven SNPs in five genes (ARNTL2, CRY2, DEC1, PER3 and RORA), in the placental genome, were associated with PA risk. Each copy of the minor allele (G) of a SNP in the RORA gene (rs2899663) was associated with a 30% reduced odds of PA (95% CI 0.52-0.95). The odds of PA increased with increasing placental-wGRS (Ptrend<0.001). The ORs were 1.00, 2.16, 3.24 and 4.48 across quartiles. Associations persisted after the maternal-wGRS was included in the model. There was evidence of an additive contribution of placental and maternal genetic contributions to PA risk. Participants with placental- and maternal-wGRS in the highest quartile, compared with those in the lowest quartile, had a 15.57-fold (95% CI 3.34-72.60) increased odds of PA. Placental variants in circadian clock-related genes are associated with PA risk; and the association persists after control of genetic variants in the maternal genome. PMID:27186326

  4. No associations between aromatase gene polymorphisms and breast cancer risk in Saudi patients

    PubMed Central

    Alanazi, Mohammed; Alabdulkarim, Huda A; Shaik, Jilani P; Al Naeem, Abdulrahman; Elrobh, Mohammad; Al Amri, Abdullah; al-Mukaynizi, Fatimah Basil; Semlali, Abdelhabib; Warsy, Arjumand; Parine, Narasimha Reddy

    2015-01-01

    Background Cytochrome P450 (CYP)19A1 encodes aromatase, the enzyme responsible for the conversion of androgens to estrogens, and may play a role in variation in outcomes among women with breast cancer. The aim of this study was to analyze the genetic association of rs4646 (A > C) and rs700518 (Val > Val) in the CYP19A1 gene with the risk of breast cancer. Methods These two single nucleotide polymorphisms (SNPs) were analyzed in a primary study group of breast cancer patients and healthy control subjects. Genotypes were determined by the TaqMan SNP analysis technique. The study data were analyzed using the chi-square or t-test and logistic regression analysis by Statistical Package for the Social Sciences version 16 software. Results rs4646 and rs700518 had no association with susceptibility to breast cancer. There was no significant association for either of these SNPs overall in breast cancer samples when compared with healthy control samples. Our data do not support a relationship between the CYP19A1 rs4646 and rs700518 SNPs and risk of breast cancer. It may be that there are ethnic differences with regard to this relationship. Conclusion This study demonstrated that CYP19A1 rs4646 and rs700518 SNPs may not be involved in the etiology of breast cancer in the Saudi population. Confirmation of our findings in larger populations of other ethnicities could provide evidence for the role of the CYP19A1 gene in breast carcinomas. PMID:26379441

  5. Aromatase Inhibition Reduces Insulin Sensitivity in Healthy Men

    PubMed Central

    Homer, Natalie Z. M.; Faqehi, Abdullah M. M.; Upreti, Rita; Livingstone, Dawn E.; McInnes, Kerry J.; Andrew, Ruth; Walker, Brian R.

    2016-01-01

    Context: Deficiency of aromatase, the enzyme that catalyzes the conversion of androgens to estrogens, is associated with insulin resistance in humans and mice. Objective: We hypothesized that pharmacological aromatase inhibition results in peripheral insulin resistance in humans. Design: This was a double-blind, randomized, controlled, crossover study. Setting: The study was conducted at a clinical research facility. Participants: Seventeen healthy male volunteers (18–50 y) participated in the study. Intervention: The intervention included oral anastrozole (1 mg daily) and placebo, each for 6 weeks with a 2-week washout period. Main Outcome Measure: Glucose disposal and rates of lipolysis were measured during a stepwise hyperinsulinemic euglycemic clamp. Data are mean (SEM). Results: Anastrozole therapy resulted in significant estradiol suppression (59.9 ± 3.6 vs 102.0 ± 5.7 pmol/L, P = < .001) and a more modest elevation of total T (25.8 ± 1.2 vs 21.4 ± 0.7 nmol/L, P = .003). Glucose infusion rate, during the low-dose insulin infusion, was lower after anastrozole administration (12.16 ± 1.33 vs 14.15 ± 1.55 μmol/kg·min, P = .024). No differences in hepatic glucose production or rate of lipolysis were observed. Conclusion: Aromatase inhibition reduces insulin sensitivity, with respect to peripheral glucose disposal, in healthy men. Local generation and action of estradiol, at the level of skeletal muscle, is likely to be an important determinant of insulin sensitivity. PMID:26967690

  6. 21 CFR 862.1585 - Human placental lactogen test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Human placental lactogen test system. 862.1585 Section 862.1585 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Systems § 862.1585 Human placental lactogen test system. (a) Identification. A human placental...

  7. 21 CFR 862.1585 - Human placental lactogen test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Human placental lactogen test system. 862.1585 Section 862.1585 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Systems § 862.1585 Human placental lactogen test system. (a) Identification. A human placental...

  8. 21 CFR 862.1585 - Human placental lactogen test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Human placental lactogen test system. 862.1585 Section 862.1585 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Systems § 862.1585 Human placental lactogen test system. (a) Identification. A human placental...

  9. Biochemical and computational insights into the anti-aromatase activity of natural catechol estrogens.

    PubMed

    Neves, Marco A C; Dinis, Teresa C P; Colombo, Giorgio; Luisa Sá E Melo, M

    2008-05-01

    High levels of endogenous estrogens are associated with increased risks of breast cancer. Estrogen levels are mainly increased by the activity of the aromatase enzyme and reduced by oxidative/conjugative metabolic pathways. In this paper, we demonstrate for the first time that catechol estrogen metabolites are potent aromatase inhibitors, thus establishing a link between aromatase activity and the processes involved in estrogen metabolism. In particular, the anti-aromatase activity of a set of natural hydroxyl and methoxyl estrogen metabolites was investigated using biochemical methods and subsequently compared with the anti-aromatase potency of estradiol and two reference aromatase inhibitors. Catechol estrogens proved to be strong inhibitors with an anti-aromatase potency two orders of magnitude higher than estradiol. A competitive inhibition mechanism was found for the most potent molecule, 2-hydroxyestradiol (2-OHE(2)) and a rational model identifying the interaction determinants of the metabolites with the enzyme is proposed based on ab initio quantum-mechanical calculations. A strong relationship between activity and electrostatic properties was found for catechol estrogens. Moreover, our results suggest that natural catechol estrogens may be involved in the control mechanisms of estrogen production.

  10. PAAn-1b and PAAn-E: two phosphorothioate antisense oligodeoxynucleotides inhibit human aromatase gene expression.

    PubMed

    Auvray, P; Sourdaine, P; Séralini, G E

    1998-12-09

    Estrogen-dependent diseases, especially breast cancers, are frequently treated with aromatase inhibitors. Another more recent strategy is the antisense technology. In this study, after predicting aromatase mRNA secondary structure, we describe the design, the efficiency, and the toxicity of two antisense phosphorothioate oligodeoxynucleotides (PAAn-1b and PAAn-E) directed toward aromatase mRNA. Indeed, 2 microM PAAn-1b and PAAn-E encapsulated with 54 microM polyethylenimine inhibit aromatase activity by 71 and 79%, respectively, in transfected 293 cells, with IC50 values of 0.2 and 0.6 microM. The mechanism of inhibition appears to be specific after using sense and scramble oligodeoxynucleotides as controls and largely decreases aromatase mRNA and protein amounts. Moreover, PAAn-1b and PAAn-E are not cytotoxic for 293 cells. This study finally provides a new strategy for aromatase inhibition. It offers new tools for studying aromatase gene expression and its role in cancer for instance, and this could be of help for the therapy of estrogen-dependent diseases.

  11. Different catalytic properties and inhibitor responses of the goldfish brain and ovary aromatase isozymes.

    PubMed

    Zhao, J; Mak, P; Tchoudakova, A; Callard, G; Chen, S

    2001-08-01

    The brain and ovarian aromatase isozymes of goldfish (Carassius auratus) are encoded by different CYP19 genes. This study measured aromatase activity in the goldfish brain tissues. For a direct comparison of the properties of the two aromatase isozymes, Chinese hamster ovary cells were stably transfected with brain- and ovary-derived cDNAs (respectively, p450 arom B and -A) and the properties of the expressed isozymes were compared. The kinetic parameters of the two isozymes were determined using androstenedione and testosterone as substrates and compared to those of human aromatase. Inhibition profile analyses on the two isozymes were performed using seven inhibitors [4-hydroxyandrostenedione, 7 alpha-(4'-amino)phenylthio-1,4-androstadiene-3,17-dione, bridge (2,19-methyleneoxy)androstene-3,17-dione, aminoglutethimide (AG), CGS 20267, ICI D1033, and vorozole]. Except for AG, the compounds tested were found to be much stronger inhibitors against the ovary enzyme than the brain enzyme. In addition, the ovary isoform was more sensitive to two phytoestrogens, chrysin and 7,8-dihydroxyflavone, than the brain form. These studies reveal that catalytic properties of the goldfish aromatase isoforms are significantly different from those of human aromatase. In addition, differences in the K(i) values of aromatase inhibitors for the two goldfish isoforms suggest structural variance in the active sites of these isozymes.

  12. Isolation and Characterization of Aromatase Inhibitors from Brassaiopsis glomerulata (Araliaceae).

    PubMed

    Balunas, Marcy J; Su, Bin; Riswan, Soedarsono; Fong, Harry H S; Brueggemeier, Robert W; Pezzuto, John M; Kinghorn, A Douglas

    2009-02-19

    The hexane- and ethyl acetate-soluble extracts of the leaves of Brassaiopsis glomerulata (Blume) Regel (Araliaceae), collected in Indonesia, were found to inhibit aromatase, the rate-limiting enzyme in the production of estrogens from androgens, in both enzyme- and cell-based aromatase inhibition (AI) assays. Bioassay-guided fractionation led to the isolation of six known compounds of the steroid and triterpenoid classes (1-6) from the hexane extract, of which 6β-hydroxystimasta-4-en-3-one (5), was moderately active in the cell-based AI assay. Fractionation of the ethyl acetate extract afforded seven pure isolates (7-13) of the modified peptide, fatty acid, monoterpenoid, and benzenoid types, including six known compounds and the new natural product, N-benzoyl-L-phenylalanine methyl ester (9). The absolute stereochemistry of 9 and the other two peptides, 7 and 8, was determined by Marfey's analysis. Linoleic acid (10) was found to be active in the enzyme-based AI assay, while 9 and (-)-dehydrololiolide (12) showed activity in the cell-based AI assay.

  13. Cytochrome C — EDRN Public Portal

    Cancer.gov

    CYCS, or cytochrome C, is an electron carrier protein that is an important part of the electron transport chain in mitochondria. The cytochrome C protein is a small heme protein that associates with the inner membrane of the mitochondrion where it accepts electrons from cytochrome b and transfers them to the cytochrome oxidase complex. Cytochrome C also plays a role in apoptosis.

  14. The mechanism by which oxygen and cytochrome c increase the rate of electron transfer from cytochrome a to cytochrome a3 of cytochrome c oxidase.

    PubMed

    Bickar, D; Turrens, J F; Lehninger, A L

    1986-11-05

    When cytochrome c oxidase is isolated from mitochondria, the purified enzyme requires both cytochrome c and O2 to achieve its maximum rate of internal electron transfer from cytochrome a to cytochrome a3. When reductants other than cytochrome c are used, the rate of internal electron transfer is very slow. In this paper we offer an explanation for the slow reduction of cytochrome a3 when reductants other than cytochrome c are used and for the apparent allosteric effects of cytochrome c and O2. Our model is based on the conventional understanding of cytochrome oxidase mechanism (i.e. electron transfer from cytochrome a/CuA to cytochrome a3/CuB), but assumes a relatively rapid two-electron transfer between cytochrome a/CuA and cytochrome a3/CuB and a thermodynamic equilibrium in the "resting" enzyme (the enzyme as isolated) which favors reduced cytochrome a and oxidized cytochrome a3. Using the kinetic constants that are known for this reaction, we find that the activating effects of O2 and cytochrome c on the rate of electron transfer from cytochrome a to cytochrome a3 conform to the predictions of the model and so provide no evidence of any allosteric effects or control of cytochrome c oxidase by O2 or cytochrome c.

  15. Placental specializations in lecithotrophic viviparous squamate reptiles.

    PubMed

    Stewart, James R

    2015-09-01

    Squamate reptiles have been thought to be predisposed to evolution of viviparity because embryos of most oviparous species undergo considerable development in the uterus prior to oviposition. A related hypothesis proposes that prolonged intrauterine gestation, an intermediate condition leading to viviparity, requires little or no physiological adjustment, other than reduction in thickness of the eggshell. This logical framework is often accompanied by an assumption that mode of parity (oviparity, viviparity) and pattern of embryonic nutrition (lecithotrophy, placentotrophy) are independent traits that evolve in sequence. Thus, specializations for viviparity should be absent in some lecithotrophic viviparous species. Studies of species of lizards with geographic variation in mode of parity challenge this scenario by demonstrating that placental specializations are correlated with viviparity. Uterine specializations for placental transport of calcium to viviparous embryos alter uterine physiology compared to oviparous females. In addition, comparative studies of oviparous and viviparous species, i.e., in which gene flow is disrupted, reveal that both uterine and embryonic structural modifications are commonly associated with viviparity, suggesting relatively rapid evolution of placental specializations. Studies of squamate reproductive biology support two hypotheses: 1) evolution of viviparity requires physiological adjustments of the uterine environment, and 2) evolution of viviparity promotes relatively rapid adaptations for placentation. Models for the evolution of viviparity from oviparity, or for reversals from viviparity to oviparity, should reflect current understanding of squamate reproductive biology and future studies should be designed to challenge these models.

  16. Preeclampsia, biomarkers, syncytiotrophoblast stress, and placental capacity.

    PubMed

    Redman, Christopher W G; Staff, Anne Cathrine

    2015-10-01

    The maternal syndrome of preeclampsia is mediated by dysfunctional syncytiotrophoblast (STB). When this is stressed by uteroplacental malperfusion, its signaling to the mother changes, as part of a highly coordinated stress response. The STB signals are both proinflammatory and dysangiogenic such that the preeclamptic mother has a stronger vascular inflammatory response than normal, with an antiangiogenic bias. Angiogenic factors have limitations as preeclampsia biomarkers, especially for prediction and diagnosis of preeclampsia at term. However, if they are recognized as markers of STB stress, their physiological changes at term demonstrate that STB stress develops in all pregnancies. The biomarkers reveal that the duration of pregnancies is restricted by placental capacity, such that there is increasing placental dysfunction, at and beyond term. This capacity includes limitations imposed by the size of the uterus, the capacity of the uteroplacental circulation and, possibly, the supply of villous progenitor trophoblast cells. Limited placental capacity explains the increasing risks of postmaturity, including preeclampsia. Early-onset preeclampsia is predictable because STB stress and changes in its biomarkers are intrinsic to poor placentation, an early pregnancy pathology. Prediction of preeclampsia at term is not good because there is no early STB pathology. Moreover, biomarkers cannot accurately diagnose term preeclampsia against a background of universal STB dysfunction, which may or may not be clinically revealed before spontaneous or induced delivery. In this sense, postterm pregnancy is, at best, a pseudonormal state. However, the markers may prove useful in screening for women with more severe problems of postmaturity.

  17. Placental Nutrient Transport and Intrauterine Growth Restriction

    PubMed Central

    Gaccioli, Francesca; Lager, Susanne

    2016-01-01

    Intrauterine growth restriction refers to the inability of the fetus to reach its genetically determined potential size. Fetal growth restriction affects approximately 5–15% of all pregnancies in the United States and Europe. In developing countries the occurrence varies widely between 10 and 55%, impacting about 30 million newborns per year. Besides having high perinatal mortality rates these infants are at greater risk for severe adverse outcomes, such as hypoxic ischemic encephalopathy and cerebral palsy. Moreover, reduced fetal growth has lifelong health consequences, including higher risks of developing metabolic and cardiovascular diseases in adulthood. Numerous reports indicate placental insufficiency as one of the underlying causes leading to altered fetal growth and impaired placental capacity of delivering nutrients to the fetus has been shown to contribute to the etiology of intrauterine growth restriction. Indeed, reduced expression and/or activity of placental nutrient transporters have been demonstrated in several conditions associated with an increased risk of delivering a small or growth restricted infant. This review focuses on human pregnancies and summarizes the changes in placental amino acid, fatty acid, and glucose transport reported in conditions associated with intrauterine growth restriction, such as maternal undernutrition, pre-eclampsia, young maternal age, high altitude and infection. PMID:26909042

  18. BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL TROPHOBLAST DIFFERENTIATION

    EPA Science Inventory

    BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL
    TROPHOBLAST DIFFERENTIATION
    Jiangang Chen, Twanda L. Thirkill, Peter N. Lohstroh, Susan R. Bielmeier, Michael
    G. Narotsky, Deborah S. Best, Randy A. Harrison, Kala Natarajan, Rex A. Pegram,
    Bill L. Lasley, and Gordon C. Do...

  19. Long-term complete remission of metastatic breast cancer, induced by a steroidal aromatase inhibitor after failure of a non-steroidal aromatase inhibitor

    PubMed Central

    Shioi, Yoshihiro; Kashiwaba, Masahiro; Inaba, Toru; Komatsu, Hideaki; Sugai, Tamotsu; Wakabayashi, Go

    2014-01-01

    Patient: Female, 56 Final Diagnosis: Breast cancer Symptoms: Solid mass in the right breast Medication: Exemestane Clinical Procedure: — Specialty: Oncology Objective: Unusual clinical course Background: The efficacy of third-generation aromatase inhibitors for hormone receptor-positive postmenopausal metastatic breast cancer is well established. Although several clinical trials have reported incomplete cross-resistance between different aromatase inhibitors, few cases of complete responses of recurrent metastatic breast cancer occurring after substituting a second aromatase inhibitor have been reported. We here present a rare case of non-steroidal aromatase inhibitor-tolerant metastatic breast cancer with long-term complete remission following substitution of a steroidal aromatase inhibitor. Case Report: We present the case of a 56-year-old Japanese woman who underwent right breast-conserving surgery for breast cancer, TNM staging T1, N0, M0, Stage I. She received adjuvant chemotherapy with 6 cycles of FEC100 and radiation therapy, and then began hormonal therapy with anastrozole. Twelve months postoperatively, computed tomography (CT) revealed multiple lung metastases. Exemestane was substituted for anastrozole. After 3 months of exemestane, CT showed that all lung metastases had completely resolved. Her complete response was maintained for 5 years: she died during a tsunami 6 years after the initial surgery. Conclusions: Substitution of a steroidal for a non-steroidal aromatase inhibitor produced a sustained complete remission in a patient with hormonal receptor-positive postmenopausal recurrent breast cancer. Achieving complete response after switching from a non-steroidal to a steroidal aromatase inhibitor in a hormonal receptor-positive postmenopausal recurrent breast cancer contributed to a higher quality of life for the patient. Further investigation is needed to identify the predictors of long-term remission following such a switch. PMID:24587856

  20. Reduced placental volume and flow in severe growth restricted fetuses

    PubMed Central

    Abulé, Renata Montes Dourado; Bernardes, Lisandra Stein; Doro, Giovana Farina; Miyadahira, Seizo; Francisco, Rossana Pulcinelli Vieira

    2016-01-01

    OBJECTIVES: To evaluate placental volume and vascular indices in pregnancies with severe fetal growth restriction and determine their correlations to normal reference ranges and Doppler velocimetry results of uterine and umbilical arteries. METHODS: Twenty-seven fetuses with estimated weights below the 3rd percentile for gestational age were evaluated. Placental volume and vascular indices, including vascularization, flow, and vascularization flow indices, were measured by three-dimensional ultrasound using a rotational technique and compared to a previously described nomogram. The observed-to-expected placental volume ratio for gestational age and observed-to-expected placental volume ratio for fetal weight were calculated. Placental parameters correlated with the Doppler velocimetry results of uterine and umbilical arteries. RESULTS: The mean uterine artery pulsatility index was negatively correlated with the observed-to-expected placental volume ratio for gestational age, vascularization index and vascularization flow index. The observed-to-expected placental volume ratio for gestational age and observed-to-expected placental volume ratio for fetal weight and vascularization index were significantly lower in the group with a bilateral protodiastolic notch. No placental parameter correlated with the umbilical artery pulsatility index. CONCLUSIONS: Pregnancies complicated by severe fetal growth restriction are associated with reduced placental volume and vascularization. These findings are related to changes in uterine artery Doppler velocimetry. Future studies on managing severe fetal growth restriction should focus on combined results of placental three-dimensional ultrasound and Doppler studies of uterine arteries. PMID:27438567

  1. Steroidal pyrazolines evaluated as aromatase and quinone reductase-2 inhibitors for chemoprevention of cancer.

    PubMed

    Abdalla, Mohamed M; Al-Omar, Mohamed A; Bhat, Mashooq A; Amr, Abdel-Galil E; Al-Mohizea, Abdullah M

    2012-05-01

    The aromatase and quinone reductase-2 inhibition of synthesized heterocyclic pyrazole derivatives fused with steroidal structure for chemoprevention of cancer is reported herein. All compounds were interestingly less toxic than the reference drug (Cyproterone(®)). The aromatase inhibitory activities of these compounds were much more potent than the lead compound resveratrol, which has an IC(50) of 80 μM. In addition, all the compounds displayed potent quinone reductase-2 inhibition. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). The aromatase and quinone reductase-2 inhibitors resulting from this study have potential value in the treatment and prevention of cancer.

  2. Successful use of aromatase inhibitor letrozole in NOA with an elevated FSH level: a case report.

    PubMed

    Zhao, D; Pan, L; Zhang, F; Pan, F; Ma, J; Zhang, X; Liu, Y

    2014-05-01

    Aromatase inhibitors inhibit the conversion of testosterone to oestrogens and could reduce serum oestradiol concentrations. Letrozole is one of aromatase inhibitors frequently used in treatment of men with oligospermia. We present the case of an infertile man with small testes and an elevated FSH level, which was diagnosed as NOA, hypospermatogenesis proven by testicular biopsy. After taking letrozole for 3 months, semen analyses by computer-aided sperm analysis present that this man had normal spermatogenesis. This is the first case report of the activation of spermatogenesis, in man who was NOA with elevated FSH level, resulting from the use of the one of aromatase inhibitors.

  3. Resolving the relationships of Paleocene placental mammals.

    PubMed

    Halliday, Thomas J D; Upchurch, Paul; Goswami, Anjali

    2017-02-01

    The 'Age of Mammals' began in the Paleocene epoch, the 10 million year interval immediately following the Cretaceous-Palaeogene mass extinction. The apparently rapid shift in mammalian ecomorphs from small, largely insectivorous forms to many small-to-large-bodied, diverse taxa has driven a hypothesis that the end-Cretaceous heralded an adaptive radiation in placental mammal evolution. However, the affinities of most Paleocene mammals have remained unresolved, despite significant advances in understanding the relationships of the extant orders, hindering efforts to reconstruct robustly the origin and early evolution of placental mammals. Here we present the largest cladistic analysis of Paleocene placentals to date, from a data matrix including 177 taxa (130 of which are Palaeogene) and 680 morphological characters. We improve the resolution of the relationships of several enigmatic Paleocene clades, including families of 'condylarths'. Protungulatum is resolved as a stem eutherian, meaning that no crown-placental mammal unambiguously pre-dates the Cretaceous-Palaeogene boundary. Our results support an Atlantogenata-Boreoeutheria split at the root of crown Placentalia, the presence of phenacodontids as closest relatives of Perissodactyla, the validity of Euungulata, and the placement of Arctocyonidae close to Carnivora. Periptychidae and Pantodonta are resolved as sister taxa, Leptictida and Cimolestidae are found to be stem eutherians, and Hyopsodontidae is highly polyphyletic. The inclusion of Paleocene taxa in a placental phylogeny alters interpretations of relationships and key events in mammalian evolutionary history. Paleocene mammals are an essential source of data for understanding fully the biotic dynamics associated with the end-Cretaceous mass extinction. The relationships presented here mark a critical first step towards accurate reconstruction of this important interval in the evolution of the modern fauna.

  4. Chronic treatment with polychlorinated biphenyls (PCB) during pregnancy and lactation in the rat Part 2: Effects on reproductive parameters, on sex behavior, on memory retention and on hypothalamic expression of aromatase and 5alpha-reductases in the offspring.

    PubMed

    Colciago, A; Casati, L; Mornati, O; Vergoni, A V; Santagostino, A; Celotti, F; Negri-Cesi, P

    2009-08-15

    The gender-specific expression pattern of aromatase and 5alpha-reductases (5alpha-R) during brain development provides neurons the right amount of estradiol and DHT to induce a dimorphic organization of the structure. Polychlorinated biphenyls (PCBs) are endocrine disruptive pollutants; exposure to PCBs through placental transfer and breast-feeding may adversely affect the organizational action of sex steroid, resulting in long-term alteration of reproductive neuroendocrinology. The study was aimed at: a) evaluating the hypothalamic expression of aromatase, 5alpha-R1 and 5alpha-R2 in fetuses (GD20), infant (PN12), weaning (PN21) and young adult (PN60) male and female rats exposed to PCBs during development; b) correlating these parameters with the time of testicular descent, puberty onset, estrous cyclicity and copulatory behavior; c) evaluating possible alterations of some non reproductive behaviors (locomotion, learning and memory, depression/anxiety behavior). A reconstituted mixture of four indicator congeners (PCB 126, 138, 153 and 180) was injected subcutaneously to dams at the dose of 10 mg/kg daily from GD15 to GD19 and then twice a week till weanling. The results indicated that developmental PCB exposure produced important changes in the dimorphic hypothalamic expression of both aromatase and the 5alpha-Rs, which were still evident in adult animals. We observed that female puberty onset occurs earlier than in control animals without cycle irregularity, while testicular descent in males was delayed. A slight but significant impairment of sexual behavior and an important alteration in memory retention were also noted specifically in males. We conclude that PCBs might affect the dimorphic neuroendocrine control of reproductive system and of other neurobiological processes.

  5. Aromatase expression in the cerebellum of the dog infected with canine distemper virus.

    PubMed

    Yarim, Murat; Gulbahar, Mustafa Yavuz; Guvenc, Tolga; Karahan, Siyami; Harada, Nobuhiro; Kabak, Yonca Betil; Karayigit, Mehmet Onder

    2010-01-01

    Aromatase is the enzyme that catalyzes the biosynthesis of estrogens. It is implicated in neuroprotection.The present study investigated aromatase expression in the cerebellum of dogs infected with canine distemper virus (CDV), a disease characterized by demyelination in the white matter of the cerebellum. The presence of CDV infection was confirmed on the basis of histopathology and immunohistochemical localization of CDV antigen in glial cells of the white matter.The number of aromatase immunoreactive astrocytes were significantly (p < 0.05) higher in CDV-infected dogs compared to control dogs. The results suggest that astrocytes respond to invasion and persistence of CDV by means of increased estrogen production.The results also suggest that the high level of estrogen expression is maintained similarly throughout all stages of the disease since the number of aromatase immunoreactive astrocytes did not vary during the different stages of CDV infection.

  6. Use of Network Inference to Unravel the Mechanisms of Action and Specificity of Aromatase Inhibitors

    EPA Science Inventory

    The vertebrate hypothalamus-pituitary-gonadal (HPG) axis is controlled through various feedback mechanisms in order to maintain a dynamic homeostasis during changing environmental conditions, including exposure to chemical stressors. In this study, three aromatase inhibitors, fad...

  7. Understanding the pathological manifestations of aromatase excess syndrome: lessons for clinical diagnosis

    PubMed Central

    Shozu, Makio; Fukami, Maki; Ogata, Tsutomu

    2014-01-01

    CYP19A1 Aromatase excess syndrome is characterized by pre- or peripubertal onset of gynecomastia due to estrogen excess because of a gain-of-function mutation in the aromatase gene (CYP19A1). Subchromosomal recombination events including duplication, deletion, and inversion has been identified. The latter two recombinations recruit novel promoters for CYP19A1 through a unique mechanism. Gynecomastia continues for life, and although the general condition is well preserved, it may cause psychological issues. Minor symptoms (variably advanced bone age and short adult height), if present, are exclusively because of estrogen excess. Serum estradiol levels are elevated in 48% of affected males, but are not necessarily useful for diagnosis. Molecular analysis of CYP19A1 mutations is mandatory to confirm aromatase excess syndrome diagnosis. Furthermore, the use of an aromatase inhibitor can ameliorate gynecomastia. PMID:25264451

  8. The binding of lignans, flavonoids and coumestrol to CYP450 aromatase: a molecular modelling study.

    PubMed

    Karkola, Sampo; Wähälä, Kristiina

    2009-03-25

    Androgens are transformed into aromatic estrogens by CYP450 aromatase in a three-step reaction consuming three equivalents of oxygen and three equivalents of NADPH. Estrogens are substrates for nuclear estrogen receptors (ERs) and play a key role in estrogen-dependent tumour cell formation and proliferation. Natural phytoestrogens are proved to be competitive inhibitors of aromatase enzyme at IC(50) values in micromolar levels. In order to understand the mechanisms involved in the binding of various phytoestrogens, we used our model of CYP450 aromatase to study the binding of phytoestrogens using molecular dynamics simulations with a bound phytoestrogen. The simulation trajectory was analysed to find the essential interactions which take place upon binding and a representative structure of the trajectory was minimized for docking studies. Sets of phytoestrogens, such as lignans, flavonoids/isoflavonoids and coumestrol, were docked into the aromatase active site and the binding modes were studied.

  9. A Quantative Adverse Outcome Pathway Linking Aromatase Inhibition in Fathead Minnows with Population Dynamics

    EPA Science Inventory

    A Quantitative Adverse Outcome Pathway Linking Aromatase Inhibition in Fathead Minnows with Population DynamicsAn adverse outcome pathway (AOP) is a qualitative description linking a molecular initiating event (MIE) with measureable key events leading to an adverse outcome (AO). ...

  10. Clotrimazole exposure modulates aromatase activity in gonads and brain during gonadal differentiation in Xenopus tropicalis frogs.

    PubMed

    Gyllenhammar, Irina; Eriksson, Hanna; Söderqvist, Anneli; Lindberg, Richard H; Fick, Jerker; Berg, Cecilia

    2009-01-31

    Clotrimazole is a pharmaceutical used for treatment of fungal infections. It has been found in surface waters outside municipal wastewater treatment plants but data are scarce regarding its effects on aquatic organisms. It is known that clotrimazole and other imidazole fungicides are inhibitors of the enzyme aromatase (CYP 19). Aromatase converts androgens into estrogens and is suggested to be involved in the sex differentiation in amphibians. The aim of the present study was to evaluate effects of larval exposure to clotrimazole on aromatase activity in brain and gonads, and on gonadal differentiation in Xenopus tropicalis frogs. Another purpose was to determine if larval exposure to ethynylestradiol (EE(2)), at a concentration known to cause male-to-female sex reversal, affects aromatase activity in brain and gonads during gonadal differentiation. Tadpoles were exposed from shortly after hatching (Nieuwkoop and Faber developmental stages 47-48) until complete metamorphosis (NF stage 66) to 6, 41, and 375 nM clotrimazole or 100 nM (nominal) EE(2). Aromatase activity was measured in the brain and gonad/kidney complex of tadpoles during gonadal differentiation (NF stage 56) and, in the clotrimazole experiment, also at metamorphosis. In clotrimazole-exposed tadpoles gonadal aromatase activity increased over exposure time in the 41 and 375 nM groups but did not differ significantly from the control group. Gonadal aromatase activity was increased in both sexes exposed to 41 and 375 nM clotrimazole at metamorphosis. Brain aromatase activity was decreased in tadpoles (NF stage 56) exposed to 375 nM clotrimazole, but at metamorphosis no differences were seen between groups or between sexes. No effects of clotrimazole on sex ratio or gonadal histology were noted at completed metamorphosis. EE(2)-exposed tadpoles had a slightly decreased gonadal aromatase activity, though not significantly different from control group, and there was no effect of EE(2) on brain aromatase

  11. Bilateral de quervain syndrome after aromatase inhibitor administration: a case report and review of the literature.

    PubMed

    Papadimitriou, Konstantinos; Kountourakis, Panteleimon; Morakis, Emmanouil; Vassiliou, Vassilios; Barbounis, Vasileios; Ardavanis, Alexandros

    2012-01-01

    Aromatase inhibitors are widely used as one of the main treatment options of both early and advanced hormone receptor-positive breast cancer in postmenopausal women. Unfortunately, musculoskeletal symptoms are often presented in patients treated with aromatase inhibitors (AIs), and, although the pathogenesis is unknown, postulated mechanisms have been described. Herein, to our knowledge, we present the first report of bilateral De Quervain syndrome related with AIs therapy with a review of the relevant literature.

  12. Bilateral De Quervain Syndrome after Aromatase Inhibitor Administration: A Case Report and Review of the Literature

    PubMed Central

    Papadimitriou, Konstantinos; Kountourakis, Panteleimon; Morakis, Emmanouil; Vassiliou, Vassilios; Barbounis, Vasileios; Ardavanis, Alexandros

    2012-01-01

    Aromatase inhibitors are widely used as one of the main treatment options of both early and advanced hormone receptor-positive breast cancer in postmenopausal women. Unfortunately, musculoskeletal symptoms are often presented in patients treated with aromatase inhibitors (AIs), and, although the pathogenesis is unknown, postulated mechanisms have been described. Herein, to our knowledge, we present the first report of bilateral De Quervain syndrome related with AIs therapy with a review of the relevant literature. PMID:22567020

  13. Temperature-dependent aromatase expression in developing diamondback terrapin (Malaclemys terrapin) embryos.

    PubMed

    Jeyasuria, P; Place, A R

    1997-04-01

    In the diamondback terrapin, Malaclemys terrapin, males hatch at incubation temperatures below 28 degrees C whereas females hatch at temperatures above 30 degrees C. When estrogen is applied to the eggs at male temperatures early in development, females are produced. These data suggest that the enzyme necessary for estrogen synthesis (CYP19, aromatase) in the developing gonad plays a critical role in sex determination in these vertebrates. Accordingly, we have begun an examination of the role and regulation of the aromatase gene in sex determination in the diamond back terrapin, Malaclemys terrapin. We have obtained full-length cDNAs for terrapin ovarian aromatase. Using reverse transcription-polymerase chain reaction (RT-PCR) on mRNA from various tissues we have determined that aromatase is expressed in the female brain and ovary, whereas it is only expressed in the brain of the male. Brain expression of aromatase occurs before stage 15, the beginning of the temperature-dependent sex determining period. Ovarian expression occurs sometime later. To quantify expression levels, we have developed a competitive RT-PCR technique to study the ontogeny of aromatase transcript levels throughout development. The sensitivity of our assay (0.001-10 atmol of transcript) permits us to analyse individual embryonic adrenal/kidney/gonadal complexes without pooling samples. Female hatchlings (stage 26) brains express higher aromatase mRNA levels than male brains (381 +/- 80 vs 202 +/- 85 atmol/microg RNA, respectively). Similarly, ovaries express significantly higher aromatase mRNA levels than hatchling testes (352 +/- 117 vs <0.001 atmol/microg RNA, respectively).

  14. Sexual dimorphism of brain aromatase activity in medaka: induction of a female phenotype by estradiol.

    PubMed

    Melo, A C; Ramsdell, J S

    2001-03-01

    In this study we identified sex-dependent dimorphism of brain aromatase in the teleost medaka and examined its regulation by sex steriods. We first investigated differential distribution of brain aromatase activity in sexually mature male and female medaka in serial coronal sections of the brain and identified the hypothalamic nuclei contained in each section using the brain atlas of medaka. In the brain of male medaka, high levels of activity are localized in sections containing the preoptic (POA) and suprachiasmatic nuclei (SC) (63-75 fmol/hr) and low levels in the nuclei periventricular dorsalis (HD), ventralis (HV), and caudalis (Hc), nuclei diffusus of lobulus inferiores (NDIL), and nuclei tuberi anteriores (TA) and posteriores (TP) (< 25 fmol/hr). In the brain of female medaka high aromatase activity is localized in sections containing the HD, HV, Hc, NDIL, TA, and TP (85-80 fmol/hr) and highly variable levels in the POA and SC (23-70 fmol/hr). The concentration and time dependency of the exposure of male medaka to estradiol on the total brain aromatase activity and morphologic sex characteristics were determined next. Estradiol increased the activity of brain aromatase in a concentration-dependent manner at 2.5 and 25 microg/L, but the increase was lower at higher concentrations of the hormone. The effect was time dependent, gradually increasing up to the fifth day of exposure, after which it reached a plateau. Estradiol induction of brain aromatase analyzed using Lineweaver-Burke plots of saturation assays revealed a non-first-order reaction. The results indicate that a positive feedback mechanism regulates brain aromatase and imply that the sexual dimorphic distribution of aromatase may be highly sensitive to physiologic cues and environmental perturbations in fish.

  15. What do we know about the mechanisms of aromatase inhibitor resistance?

    PubMed Central

    Chen, Shiuan; Masri, Selma; Wang, Xin; Phung, Sheryl; Yuan, Yate-Ching; Wu, Xiwei

    2007-01-01

    Clinical trials have demonstrated the importance of aromatase inhibitor (AI) therapy in the effective treatment of hormone-dependent breast cancers. Yet, as with all prolonged drug therapy, resistance to aromatase inhibitors does develop. To date, the precise mechanism responsible for resistance to aromatase inhibitors is not completely understood. In this paper, several mechanisms of de novo/intrinsic resistance and acquired resistance to AIs are discussed. These mechanisms are hypothesized based on important findings from a number of laboratories. To better understand this question, our lab has generated, in vitro, breast cancer cell lines that are resistant to aromatase inhibitors. Resistant cell lines were generated over a prolonged period of time using the MCF-7aro (aromatase overexpressed) breast cancer line. These cell lines are resistant to the aromatase inhibitors letrozole, anastrozole and exemestane and the anti-estrogen tamoxifen, for comparison. Two types of resistant cell lines have been generated, those that grow in the presence of Testosterone (T) which is needed for cell growth, and resistant lines that are cultured in the presence of inhibitor only (no T). In addition to functional characterization of aromatase and ERα in these resistant cell lines, microarray analysis has been employed in order to determine differential gene expression within the aromatase inhibitor resistant cell lines versus tamoxifen, in order to better understand the mechanism responsible for AI resistance on a genome-wide scale. We anticipate that our studies will generate important information on the mechanisms of AI resistance. Such information can be valuable for the development of treatment strategies against AI resistant breast cancers. PMID:17055257

  16. History of aromatase: saga of an important biological mediator and therapeutic target.

    PubMed

    Santen, R J; Brodie, H; Simpson, E R; Siiteri, P K; Brodie, A

    2009-06-01

    Aromatase is the enzyme that catalyzes the conversion of androgens to estrogens. Initial studies of its enzymatic activity and function took place in an environment focused on estrogen as a component of the birth control pill. At an early stage, investigators recognized that inhibition of this enzyme could have major practical applications for treatment of hormone-dependent breast cancer, alterations of ovarian and endometrial function, and treatment of benign disorders such as gynecomastia. Two general approaches ultimately led to the development of potent and selective aromatase inhibitors. One targeted the enzyme using analogs of natural steroidal substrates to work out the relationships between structure and function. The other approach initially sought to block adrenal function as a treatment for breast cancer but led to the serendipitous finding that a nonsteroidal P450 steroidogenesis inhibitor, aminoglutethimide, served as a potent but nonselective aromatase inhibitor. Proof of the therapeutic concept of aromatase inhibition involved a variety of studies with aminoglutethimide and the selective steroidal inhibitor, formestane. The requirement for even more potent and selective inhibitors led to intensive molecular studies to identify the structure of aromatase, to development of high-sensitivity estrogen assays, and to "mega" clinical trials of the third-generation aromatase inhibitors, letrozole, anastrozole, and exemestane, which are now in clinical use in breast cancer. During these studies, unexpected findings led investigators to appreciate the important role of estrogens in males as well as in females and in multiple organs, particularly the bone and brain. These studies identified the important regulatory properties of aromatase acting in an autocrine, paracrine, intracrine, neurocrine, and juxtacrine fashion and the organ-specific enhancers and promoters controlling its transcription. The saga of these studies of aromatase and the ultimate

  17. Two aromatase inhibitors inhibit the ability of a third to promote mating in male rats.

    PubMed

    Yahr, Pauline

    2015-09-01

    Aromatase, the enzyme that aromatizes androstenedione (A) to estrone and testosterone (T) to estradiol (E), affects androgen control of male sex behavior in many vertebrates. In male monkeys, rats and quail, E mimics the ability of T to promote mating, and aromatase inhibitors block mating induced by T but not E. Aromatase inhibitors include androgens with different A-rings than T and A, e.g., 1,4,6-androstatriene-3,17-dione (ATD), azoles, e.g., fadrozole, and androgens α-halogenated at carbon 6, e.g., 6α-bromoA, 6α-fluoroA and 6α-fluoroT. 6α-FluoroT is the only 6α-halogenated androgen studied in regard to mating. It promotes mating in male rats and quail and was studied, before it was known to inhibit aromatase, because it cannot be aromatized yet has the same A-ring as T. 6α-FluoroT might promote mating by binding estrogen receptors (ER) directly, i.e., unassisted, or by metabolism to an androgen that binds ER. Since neither process would require aromatase, this study tested both hypotheses by determining how mating induced in castrated male rats by 6α-fluoroT is affected by ATD and fadrozole. Both aromatase inhibitors inhibited the effects of 6α-fluoroT on mating. Thus, 6α-fluoroT does not promote mating by direct ER binding or metabolism to another androgen. Since aromatase underlies a process in which 6α-fluoroT, unlike most nonaromatizable androgens, mimics T effects on male sex behavior, the process must involve a feature that 6α-fluoroT shares with T but not other nonaromatizable androgens. A-ring structure is a candidate. A hypothesis is also offered for how aromatase may participate without aromatizing the androgen.

  18. Cytochromes P450

    PubMed Central

    Bak, Søren; Beisson, Fred; Bishop, Gerard; Hamberger, Björn; Höfer, René; Paquette, Suzanne; Werck-Reichhart, Danièle

    2011-01-01

    There are 244 cytochrome P450 genes (and 28 pseudogenes) in the Arabidopsis genome. P450s thus form one of the largest gene families in plants. Contrary to what was initially thought, this family diversification results in very limited functional redundancy and seems to mirror the complexity of plant metabolism. P450s sometimes share less than 20% identity and catalyze extremely diverse reactions leading to the precursors of structural macromolecules such as lignin, cutin, suberin and sporopollenin, or are involved in biosynthesis or catabolism of all hormone and signaling molecules, of pigments, odorants, flavors, antioxidants, allelochemicals and defense compounds, and in the metabolism of xenobiotics. The mechanisms of gene duplication and diversification are getting better understood and together with co-expression data provide leads to functional characterization. PMID:22303269

  19. Aromatase expression is linked to estrogenic sensitivity of periurethral muscles in female rabbits.

    PubMed

    de los Ángeles Carrasco-Ruiz, María; García-Villamar, Verónica; López-García, Kenia; Sánchez-García, Octavio; Pacheco, Pablo; Cuevas, Estela; Martínez-Gómez, Margarita; Castelán, Francisco

    2015-06-01

    Beyond its role in the conversion of androgens to estrogens, the expression of aromatase could influence on the estrogenic signalling in targeted tissues. Considering the well-defined biochemical and physiological differences between the pubococcygeus (Pcm) and bulbospongiosus (Bsm) muscles in female rabbits, it is presently hypothesized that the aromatase expression is differentially linked to the estrogen sensitivity of each muscle. To this end, serum estradiol levels and the aromatase expression, presence of ERα and ERβ and morphometry were evaluated in the Pcm and Bsm of female rabbits allocated in control, ovariectomized (OVX) and OVX treated with estradiol benzoate (OVX + EB) groups. Aromatase expression was high in the Pcm. Independently to serum estradiol, ovariectomy increased aromatase expression in the Pcm while decreased it in the Bsm. The EB treatment avoided the effect of ovariectomy only in the Pcm. The number of immunoreactive nuclei anti-ERα and anti-ERβ was high in the Pcm of OVX and OVX + EB rabbits, while those in the Bsm remained unchanged. The number of peripheral nuclei per fibre and the cross-sectional area-to-myonucleus ratio were modified only in the Pcm. Our findings support aromatase expression in the Pcm, and Bsm of rabbits is differentially linked to estrogenic sensitivity of each muscle.

  20. Role of P-450 aromatase in sex determination of the diamondback terrapin, Malaclemys terrapin.

    PubMed

    Jeyasuria, P; Roosenburg, W M; Place, A R

    1994-09-15

    Sex determination in the diamondback terrapin, Malaclemys terrapin, is temperature-dependent. Eggs incubated at 31 degrees C, and above, hatch in approximately 45 days as females. Eggs incubated below 27 degrees C hatch in about 60 days as males. Sex is not reversible after hatching. Nest temperatures in the wild can be as low as 20 degrees C and as high as 37 degrees C with as much as a 10 degrees C diel cycle. The shortest incubation time measured in nature was 56 days and the longest approaching 120 days. Nests in our study site produced predominantly (> 95%) male hatchlings. Treatment of developing embryos with estrogen produces females at male producing temperatures while treatment with fadrozole (a nonsteroidal aromatase inhibitor) induces partial male-like gonads. Treatment with a steroidal aromatase inhibitor (4-hydroxyandrostenedione, 4-OHA) had no effect on sex determination. Both fadrozole and 4-OHA are potent competitive inhibitors (Ki approximately 40-50 nM) for terrapin in vitro aromatase activity. These findings are consistent with aromatase expression being a key step in sex determination of terrapins. We have cloned a partial single copy P-450 aromatase from the terrapin using a cDNA library constructed from ovarian mRNA. This partial clone is highly homologous to other vertebrate aromatases.

  1. The Evolutionary Tale and Future Directions of Aromatase Inhibitors in Breast Carcinoma.

    PubMed

    Bhattacharjee, Dipanjan; Kumari, Meena K; Avin, S; Babu Amberkar, Mohan V

    2017-03-27

    Aromatase inhibitors have often been likened to that of 'medical scalpels' for the treatment of breast carcinoma. By inhibiting the singular step of aromatisation, they have proven to be extremely effective allies in the treatment of breast cancer among postmenopausal women. However, their relevance soon may not be limited to the post-menopausal age group alone. Recent studies have hinted at their utility amongst the pre-menopausal women; combined with ovarian ablation techniques, aromatase inhibitors may prove to be equally effective and more, as compared to tamoxifen in this age-group. Additionally, explorations aimed at ascertaining their potential utility as an effective preventive strategy against breast carcinoma have yielded encouraging results. However, for aromatase inhibitors to be able to attain their full potential, further strategic fine-tuning aimed at maximising their efficacy and minimising their potentially far-reaching adverse effects, is the need of the hour. Despite the recent diversification, the issue of resistance to aromatase inhibitors in breast cancer threatens to derail the advances so gained till date. Fortunately, a few novel ploys have come to the fore, for instance combining aromatase inhibitors with HER-2 antibodies that could potentially help circumvent the menace of resistance in the near future. Till date, the utility of aromatase inhibitors can at best be described as one-dimensional. However, with the unearthing of potential new avenues for its application, this assortment of molecules today stands on the precipice of ushering in a new revolution in the treatment of breast carcinom.

  2. Cotargeting of CYP-19 (aromatase) and emerging, pivotal signalling pathways in metastatic breast cancer

    PubMed Central

    Daldorff, Stine; Mathiesen, Randi Margit Ruud; Yri, Olav Erich; Ødegård, Hilde Presterud; Geisler, Jürgen

    2017-01-01

    Aromatase inhibition is one of the cornerstones of modern endocrine therapy of oestrogen receptor-positive (ER+) metastatic breast cancer (MBC). The nonsteroidal aromatase inhibitors anastrozole and letrozole, as well as the steroidal aromatase inactivator exemestane, are the preferred drugs and established worldwide in all clinical phases of the disease. However, although many patients suffering from MBC experience an initial stabilisation of their metastatic burden, drug resistance and disease progression occur frequently, following in general only a few months on treatment. Extensive translational research during the past two decades has elucidated the major pathways contributing to endocrine resistance and paved the way for clinical studies investigating the efficacy of novel drug combinations involving aromatase inhibitors and emerging drugable targets like mTOR, PI3K and CDK4/6. The present review summarises the basic research that provided the rationale for new drug combinations involving aromatase inhibitors and the main findings of pivotal clinical trials that have already started to change our way to treat hormone-sensitive MBC. The challenging situation of oestrogen receptor-positive and human epidermal growth factor receptor 2-positive (HER2+) MBC is also shortly reviewed to underline the complexity of the clinical scenario in the heterogeneous subgroups of hormone receptor-positive breast cancer patients and the increasing need for personalised medicine. Finally, we summarise some of the promising findings made with the combination of aromatase inhibitors with other potent endocrine treatment options like fulvestrant, a selective oestrogen receptor downregulator. PMID:27923036

  3. Highly potent first examples of dual aromatase-steroid sulfatase inhibitors based on a biphenyl template.

    PubMed

    Woo, L W Lawrence; Jackson, Toby; Putey, Aurélien; Cozier, Gyles; Leonard, Philip; Acharya, K Ravi; Chander, Surinder K; Purohit, Atul; Reed, Michael J; Potter, Barry V L

    2010-03-11

    Single agents against multiple drug targets are of increasing interest. Hormone-dependent breast cancer (HDBC) may be more effectively treated by dual inhibition of aromatase and steroid sulfatase (STS). The aromatase inhibitory pharmacophore was thus introduced into a known biphenyl STS inhibitor to give a series of novel dual aromatase-sulfatase inhibitors (DASIs). Several compounds are good aromatase or STS inhibitors and DASI 20 (IC(50): aromatase, 2.0 nM; STS, 35 nM) and its chlorinated congener 23 (IC(50): aromatase, 0.5 nM; STS, 5.5 nM) are examples that show exceptional dual potency in JEG-3 cells. Both biphenyls share a para-sulfamate-containing ring B and a ring A, which contains a triazol-1-ylmethyl meta to the biphenyl bridge and para to a nitrile. At 1 mg/kg po, 20 and 23 reduced plasma estradiol levels strongly and inhibited liver STS activity potently in vivo. 23 is nonestrogenic and potently inhibits carbonic anhydrase II (IC(50) 86 nM). A complex was crystallized and its structure was solved by X-ray crystallography. This class of DASI should encourage further development toward multitargeted therapeutic intervention in HDBC.

  4. Inhibitory effects of pharmacological doses of melatonin on aromatase activity and expression in rat glioma cells.

    PubMed

    González, A; Martínez-Campa, C; Mediavilla, M D; Alonso-González, C; Sánchez-Barceló, E J; Cos, S

    2007-09-17

    Melatonin exerts oncostatic effects on different kinds of neoplasias, especially on oestrogen-dependent tumours. Recently, it has been described that melatonin, on the basis of its antioxidant properties, inhibits the growth of glioma cells. Glioma cells express oestrogen receptors and have the ability to synthesise oestrogens from androgens. In the present study, we demonstrate that pharmacological concentrations of melatonin decreases the growth of C6 glioma cells and reduces the local biosynthesis of oestrogens, through the inhibition of aromatase, the enzyme that catalyses the conversion of androgens into oestrogens. These results are supported by three types of evidence. Firstly, melatonin counteracts the growth stimulatory effects of testosterone on glioma cells, which is dependent on the local synthesis of oestrogens from testosterone. Secondly, we found that melatonin reduces the aromatase activity of C6 cells, measured by the tritiated water release assay. Finally, by (RT)-PCR, we found that melatonin downregulates aromatase mRNA steady-state levels in these glioma cells. We conclude that melatonin inhibits the local production of oestrogens decreasing aromatase activity and expression. By analogy to the implications of aromatase in other forms of oestrogen-sensitive tumours, it is conceivable that the modulation of the aromatase by pharmacological melatonin may play a role in the growth of glioblastomas.

  5. Netrins and Their Roles in Placental Angiogenesis

    PubMed Central

    Dakouane-Giudicelli, Mbarka; Alfaidy, Nadia; de Mazancourt, Philippe

    2014-01-01

    Netrins, a family of laminin-related proteins, were originally identified as axonal guidance molecules. Subsequently, netrins were found to modulate various biological processes including morphogenesis, tumorogenesis, adhesion, and, recently, angiogenesis. In human placenta, the most vascularized organ, the presence of netrins has also been reported. Recent studies demonstrated the involvement of netrins in the regulation of placental angiogenesis. In this review we focused on the role of netrins in human placental angiogenesis. Among all netrins examined, netrin-4 and netrin-1 have been found to be either pro- or antiangiogenic factors. These opposite effects appear to be related to the endothelial cell phenotype studied and seem also to depend on the receptor type to which netrin binds, that is, the canonical receptor member of the DCC family, the members of the UNC5 family, or the noncanonical receptor members of the integrin family or DSCAM. PMID:25143950

  6. Neurotrophins: Role in Placental Growth and Development.

    PubMed

    Sahay, A S; Sundrani, D P; Joshi, S R

    2017-01-01

    Neurotrophins, a family of closely related proteins, were originally identified as growth factors for survival, development, and function of neurons in both the central and peripheral nervous systems. Subsequently, neurotrophins have been shown to have functions in immune and reproductive systems. Neurotrophins like nerve growth factor and brain-derived neurotrophic factor (BDNF) are known to play an important role during pregnancy in the process of placental angiogenesis and maturation. Several studies have demonstrated the presence of neurotrophins in the human placenta. The current chapter reviews studies demonstrating the role of neurotrophins during pregnancy particularly in placental development. This chapter also focuses on the regional changes in neurotrophins in the human placenta and its interactions with other growth factors. Future research is needed to understand the mechanisms through which neurotrophins influence the growth and development of the placenta and pregnancy outcome.

  7. Functional genetic polymorphisms in the aromatase gene CYP19 vary the response of breast cancer patients to neoadjuvant therapy with aromatase inhibitors.

    PubMed

    Wang, Liewei; Ellsworth, Katarzyna A; Moon, Irene; Pelleymounter, Linda L; Eckloff, Bruce W; Martin, Yvette N; Fridley, Brooke L; Jenkins, Gregory D; Batzler, Anthony; Suman, Vera J; Ravi, Saranya; Dixon, J Michael; Miller, William R; Wieben, Eric D; Buzdar, Aman; Weinshilboum, Richard M; Ingle, James N

    2010-01-01

    Aromatase (CYP19) is a critical enzyme in estrogen biosynthesis and aromatase inhibitors (AI) are employed widely for endocrine therapy in postmenopausal women with breast cancer. We hypothesized that single nucleotide polymorphisms (SNPs) in the CYP19 gene may alter the effectiveness of AI therapy in the neoadjuvant setting. Genomic DNA was obtained for sequencing from 52 women pre-AI and post-AI treatment in this setting. Additionally, genomic DNA obtained from 82 samples of breast cancer and 19 samples of normal breast tissue was subjected to resequencing. No differences in CYP19 sequence were observed between tumor and germ-line DNA in the same patient. A total of 48 SNPs were identified including 4 novel SNPs when compared with previous resequencing data. For genotype-phenotype association studies, we determined the levels of aromatase activity, estrone, estradiol, and tumor size in patients pre-AI and post-AI treatment. We defined two tightly linked SNPs (rs6493497 and rs7176005 in the 5'-flanking region of CYP19 exon 1.1) that were significantly associated with a greater change in aromatase activity after AI treatment. In a follow-up study of 200 women with early-stage breast cancer who were treated with adjuvant anastrozole, these same two SNPs were also associated with higher plasma estradiol levels in patients pre-AI and post-AI treatment. Electrophoretic mobility shift and reporter gene assays confirmed likely functional effects of these two SNPs on transcription of CYP19. Our findings indicate that two common genetic polymorphisms in the aromatase gene CYP19 vary the response of breast cancer patients to aromatase inhibitors.

  8. Chronic Placental Inflammation in Twin Pregnancies

    PubMed Central

    Bang, Heejin; Bae, Go Eun; Park, Ha Young; Kim, Yeon Mee; Choi, Suk-Joo; Oh, Soo-young; Roh, Cheong-Rae; Kim, Jung-Sun

    2015-01-01

    Background: Chronic placental inflammation, such as villitis of unknown etiology (VUE) and chronic chorioamnionitis (CCA), is considered a placental manifestation of maternal anti-fetal rejection. The aim of this study is to investigate its frequency in twin pregnancies compared to singleton pregnancies. Methods: Three hundred twin placentas and 1,270 singleton placentas were consecutively collected at a tertiary medical center in Seoul, Republic of Korea from 2009 to 2012. Hematoxylin and eosin sections of tissue samples (full-thickness placental disc and chorioamniotic membranes) were reviewed. Results: Non-basal VUE was more frequent in twin placentas than in singleton placentas (6.0% vs 3.2%, p < .05). In preterm birth, CCA was found less frequently in twin placentas than in singleton placentas (9.6% vs 14.8%, p < .05), reaching its peak at an earlier gestational age in twin placentas (29–32 weeks) than in singleton placentas (33–36 weeks). CCA was more frequent in twin pregnancies with babies of a different sex than with those with the same sex (13.8% vs 6.9%, p=.052). Separate dichorionic diamniotic twin placentas were affected by chronic deciduitis more frequently than singleton placentas (16.9% vs 9.7%, p<.05). Conclusions: The higher frequency of non-basal VUE in twin placentas and of CCA in twin placentas with different fetal sex supports the hypothesis that the underlying pathophysiological mechanism is maternal anti-fetal rejection related to increased fetal antigens in twin pregnancies. The peak of CCA at an earlier gestational age in twin placentas than in singleton placentas suggests that CCA is influenced by placental maturation. PMID:26459409

  9. Quantitative analysis of long-form aromatase mRNA in the male and female rat brain.

    PubMed

    Tabatadze, Nino; Sato, Satoru M; Woolley, Catherine S

    2014-01-01

    In vitro studies show that estrogens acutely modulate synaptic function in both sexes. These acute effects may be mediated in vivo by estrogens synthesized within the brain, which could fluctuate more rapidly than circulating estrogens. For this to be the case, brain regions that respond acutely to estrogens should be capable of synthesizing them. To investigate this question, we used quantitative real-time PCR to measure expression of mRNA for the estrogen-synthesizing enzyme, aromatase, in different brain regions of male and female rats. Importantly, because brain aromatase exists in two forms, a long form with aromatase activity and a short form with unknown function, we targeted a sequence found exclusively in long-form aromatase. With this approach, we found highest expression of aromatase mRNA in the amygdala followed closely by the bed nucleus of the stria terminalis (BNST) and preoptic area (POA); we found moderate levels of aromatase mRNA in the dorsal hippocampus and cingulate cortex; and aromatase mRNA was detectable in brainstem and cerebellum, but levels were very low. In the amygdala, gonadal/hormonal status regulated aromatase expression in both sexes; in the BNST and POA, castration of males down-regulated aromatase, whereas there was no effect of estradiol in ovariectomized females. In the dorsal hippocampus and cingulate cortex, there were no differences in aromatase levels between males and females or effects of gonadal/hormonal status. These findings demonstrate that long-form aromatase is expressed in brain regions that respond acutely to estrogens, such as the dorsal hippocampus, and that gonadal/hormonal regulation of aromatase differs among different brain regions.

  10. Placentation in mammals once grouped as insectivores.

    PubMed

    Carter, Anthony M; Enders, Allen C

    2010-01-01

    Interest in insectivoran grade mammals has been reawakened by taxonomic changes that place tenrecs and golden moles in a new order and separate hedgehogs from moles, shrews and solenodons. This survey of their placentation shows there is great variation even within families. As an example three subfamilies of tenrec have been examined. The interhemal region is cellular hemomonochorial in Echinops and Microgale but endotheliochorial in Micropotamogale. Golden moles, which are placed in the same order, have hemodichorial placentation. Many insectivores have complex arrangements for histotrophic nutrition involving columnar trophoblast cells. These range from areolae in moles through complexly folded hemophagous regions in tenrecs to the trophoblastic annulus in shrews. Of these placental characters, few offer support to current phylogenies. However, the case for placing hedgehogs and gymnures in a separate order (Erinaceomorpha) is bolstered by the presence of interstitial implantation, amniogenesis by cavitation, a hemochorial barrier and a prominent spongy zone; these features do not occur in shrews, moles or solenodons (Soricomorpha). Three insectivoran grade mammals deserve close attention as they have been selected for genome sequencing. One of these, the European hedgehog (Erinaceus europaeus), has not been studied with current methodology and renewed investigation of this or the closely related genus Atelerix should be a priority.

  11. Targeting Cytochrome P450 Enzymes: A New Approach in Anti-cancer Drug Development

    PubMed Central

    Bruno, Robert D.; Njar, Vincent C.O.

    2007-01-01

    Cytochrome P450s (CYPs) represent a large class of heme-containing enzymes that catalyze the metabolism of multitudes of substrates both endogenous and exogenous. Until recently, however, CYPs have been largely overlooked in cancer drug development, acknowledged only for their role in Phase I metabolism of chemotherapeutics. The first successful strategy targeting CYP enzymes in cancer therapy was the development of potent inhibitors of CYP19 (aromatase) for the treatment of breast cancer. Aromatase inhibitors ushered in a new era in hormone ablation therapy for estrogen dependent cancers, and have paved the way for similar strategies (i.e. inhibition of CYP17) that combat androgen dependent prostate cancer. Identification of CYPs involved in the inactivation of anti-cancer metabolites of Vitamin D3 and Vitamin A has triggered development of agents that target these enzymes as well. The discovery of the over-expression of exogenous metabolizing CYPs, such as CYP1B1, in cancer cells has roused interest in the development of inhibitors for chemoprevention and of prodrugs designed to be activated by CYPs only in cancer cells. Finally, the expression of CYPs within tumors has been utilized in the development of bioreductive molecules that are activated by CYPs only under hypoxic conditions. This review offers the first comprehensive analysis of strategies in drug development that either inhibit or exploit CYP enzymes for the treatment of cancer. PMID:17544277

  12. The placental mammal ancestor and the post-K-Pg radiation of placentals.

    PubMed

    O'Leary, Maureen A; Bloch, Jonathan I; Flynn, John J; Gaudin, Timothy J; Giallombardo, Andres; Giannini, Norberto P; Goldberg, Suzann L; Kraatz, Brian P; Luo, Zhe-Xi; Meng, Jin; Ni, Xijun; Novacek, Michael J; Perini, Fernando A; Randall, Zachary S; Rougier, Guillermo W; Sargis, Eric J; Silcox, Mary T; Simmons, Nancy B; Spaulding, Michelle; Velazco, Paúl M; Weksler, Marcelo; Wible, John R; Cirranello, Andrea L

    2013-02-08

    To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obtained a phylogenetic tree that, when calibrated with fossils, shows that crown clade Placentalia and placental orders originated after the K-Pg boundary. Many nodes discovered using molecular data are upheld, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea (elephants) and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats). Our tree suggests that Placentalia first split into Xenarthra and Epitheria; extinct New World species are the oldest members of Afrotheria.

  13. Topological Analysis of Placental Arteries:. Correlation with Neonatal Growth

    NASA Astrophysics Data System (ADS)

    Yamada, H.; Yakubo, K.

    2007-07-01

    The aim of study was to assess whether any network index of placental surface arteries was associated with neonatal birth weight. Twenty-six placentas were randomly selected between 34 and 41 weeks of gestational ages. Placental weights ranged 385 to 770 g; and neonatal weights ranged 1960 to 3680 g. After visualization of placental surface arteries by a milk injection method, network indices including the number of nodes, network density, network diameter, average distance of nodes, and the degree centralization were determined. These network indices and placental weights were compared with neonatal birth weights. The Number of nodes, network density, network diameter, average distance of nodes, and the degree centralization were found to be as follows (Mean ± SD); 84.7 ± 29.3, 0.0262 ± 0.0088, 15.8 ± 2.77, 7.83 ± 1.13, 0.0263 ± 0.0091, respectively. We found that neonatal birth weights correlate with the number of nodes of placental surface arteries (correlation coefficient R=0.40) and placental weights (R=0.52) both. However, the number of nodes of placental surface arteries was not associated with the placental weights or the gestational age. We for the first time found that a topological factor, i.e., the number of nodes of placental surface arteries correlated with neonatal growth. There was no correlation between numbers of nodes and placental weights. This suggests that the number of nodes affects fetal growth independent of placental weights. A topological factor of placental vasculization might significantly affect fetal growth in utero and determine risks of vascular diseases in their future lives.

  14. Novel inhibitor discovery against aromatase through virtual screening and molecular dynamic simulation: a computational approach in drug design.

    PubMed

    Mirzaie, Sako; Chupani, Latifeh; Asadabadi, Ebrahim Barzegari; Shahverdi, Ahmad Reza; Jamalan, Mostafa

    2013-01-01

    Inhibition of aromatase (CYTP450) as a key enzyme in the estrogen biosynthesis could result in regression of estrogen-dependent tumors and even preventing the promotion of breast cancer. Although today potent steroid and non-steroid inhibitors of aromatase are available, isoflavanone derivatives as natural compounds with least side effects have been described as the candidate for a new generation of aromatase inhibitors. 2a as an isoflavanone derivative is the most potent inhibitor of aromatase, synthesized by Bonfield et al. (2012[7]). In our computational study, the mentioned compound was used as the template for virtual screening. Between 286 selected compounds with 70 % of structural similarity to 2a, 150 of them showed lower docking energy in comparison with 2a. Compound 2a_1 with 11.2 kcal/mol had the lowest docking energy. Interaction of 2a_1 with aromatase was further investigated and compared with 2a and androstenedione (ASD) as a natural substrate of aromatase, through 20 ns of molecular dynamic simulation. Analysis of trajectories showed, while ASD interacts with aromatase through hydrogen bonds and 2a just interacts via hydrophobic forces, 2a_1 not only accommodates in the hydrophobic active site of aromatase in a suitable manner but it also makes a stable coordination with iron atom of aromatase heme group via OB.

  15. Evidence of sexual dimorphism in placental vitamin D metabolism: Testosterone inhibits calcitriol-dependent cathelicidin expression.

    PubMed

    Olmos-Ortiz, Andrea; García-Quiroz, Janice; López-Marure, Rebeca; González-Curiel, Irma; Rivas-Santiago, Bruno; Olivares, Aleida; Avila, Euclides; Barrera, David; Halhali, Ali; Caldiño, Felipe; Larrea, Fernando; Díaz, Lorenza

    2016-10-01

    Male fetus and neonates show increased immune vulnerability compared to females, which results in a higher risk of perinatal infections. These differences could partially be due to sex steroids differential modulation of vitamin D metabolism; since calcitriol, the most active vitamin D metabolite, regulates immune responses and transcriptionally induces the antimicrobial peptide cathelicidin in the human placenta. Calcitriol availability depends on CYP27B1 and CYP24A1 expression, the cytochromes involved in its synthesis and degradation, respectively. However, the effects of testosterone upon these enzymes and the final biological outcome upon the calcitriol-dependent immune-target cathelicidin in the placenta have not been studied. In this study we show that testosterone significantly inhibited CYP27B1 while stimulated CYP24A1 gene expression in cultured trophoblasts. These effects were accompanied by CREB activation through cAMP-independent and androgen receptor-dependent mechanisms. Male placental cotyledons showed reduced basal CYP27B1 and cathelicidin gene expression compared to females (P<0.05). Testosterone concentration was higher in the cord blood of male neonates (P=0.007), whereas cathelicidin levels were lesser compared to females (P=0.002). Altogether our results suggest that male placentas produce less cathelicidin due to decreased calcitriol bioavailability. We propose that the observed sex-dependent differences in placental vitamin D metabolism contribute in fetal responses to infections and could partially explain why the increased male fetuses immune vulnerability. Moreover, gestational hyperandrogenemia could adversely affect placental vitamin D metabolism independently of fetal sex.

  16. Placental Protein 13 (PP13) – A Placental Immunoregulatory Galectin Protecting Pregnancy

    PubMed Central

    Than, Nándor Gábor; Balogh, Andrea; Romero, Roberto; Kárpáti, Éva; Erez, Offer; Szilágyi, András; Kovalszky, Ilona; Sammar, Marei; Gizurarson, Sveinbjorn; Matkó, János; Závodszky, Péter; Papp, Zoltán; Meiri, Hamutal

    2014-01-01

    Galectins are glycan-binding proteins that regulate innate and adaptive immune responses, and some confer maternal-fetal immune tolerance in eutherian mammals. A chromosome 19 cluster of galectins has emerged in anthropoid primates, species with deep placentation and long gestation. Three of the five human cluster galectins are solely expressed in the placenta, where they may confer additional immunoregulatory functions to enable deep placentation. One of these is galectin-13, also known as Placental Protein 13 (PP13). It has a “jelly-roll” fold, carbohydrate-recognition domain and sugar-binding preference resembling other mammalian galectins. PP13 is predominantly expressed by the syncytiotrophoblast and released from the placenta into the maternal circulation. Its ability to induce apoptosis of activated T cells in vitro, and to divert and kill T cells as well as macrophages in the maternal decidua in situ, suggests important immune functions. Indeed, mutations in the promoter and an exon of LGALS13 presumably leading to altered or non-functional protein expression are associated with a higher frequency of preeclampsia and other obstetrical syndromes, which involve immune dysregulation. Moreover, decreased placental expression of PP13 and its low concentrations in first trimester maternal sera are associated with elevated risk of preeclampsia. Indeed, PP13 turned to be a good early biomarker to assess maternal risk for the subsequent development of pregnancy complications caused by impaired placentation. Due to the ischemic placental stress in preterm preeclampsia, there is increased trophoblastic shedding of PP13 immunopositive microvesicles starting in the second trimester, which leads to high maternal blood PP13 concentrations. Our meta-analysis suggests that this phenomenon may enable the potential use of PP13 in directing patient management near to or at the time of delivery. Recent findings on the beneficial effects of PP13 on decreasing blood pressure

  17. Placental programming of blood pressure in Indian children

    PubMed Central

    Winder, Nicola R; Krishnaveni, Ghattu V; Hill, Jacqueline C; Karat, Chitra LS; Fall, Caroline HD; Veena, Sargoor R; Barker, David JP

    2011-01-01

    Aim To determine whether the size and shape of the placental surface predict blood pressure in childhood. Methods We studied blood pressure in 471 nine-year-old Indian children whose placental length, breadth and weight were measured in a prospective birth cohort study. Results In the daughters of short mothers (placental breadth increased (β = 0.69 mmHg/cm, p = 0.05) and as the ratio of placental surface area to birthweight increased (p = 0.0003). In the daughters of tall mothers, SBP rose as the difference between placental length and breadth increased (β = 1.40 mmHg/cm, p = 0.007), that is as the surface became more oval. Among boys, associations with placental size were only statistically significant after adjusting for current BMI and height. After adjustment, SBP rose as placental breadth, area and weight decreased (for breadth β = −0.68 mmHg/cm, p < 0.05 for all three measurements). Conclusions The size and shape of the placental surface predict childhood blood pressure. Blood pressure may be programmed by variation in the normal processes of placentation: these include implantation, expansion of the chorionic surface in mid-gestation and compensatory expansion of the chorionic surface in late gestation. PMID:21166711

  18. [Placental 3D Doppler angiography: current and upcoming applications].

    PubMed

    Duan, J; Perdriolle-Galet, E; Chabot-Lecoanet, A-C; Callec, R; Beaumont, M; Chavatte-Palmer, P; Tsatsaris, V; Morel, O

    2015-02-01

    The placental dysfunction, which seems to be caused by a defect of trophoblastic invasion and impaired uterine vascular remodeling since the first trimester, is responsible in a non-exclusive way for the chronic placental hypoxia, resulting secondarily in the intra-uterine growth restriction (IUGR) and/or pre-eclampsia (PE). The quality of utero-placental vasculature is essential for a proper fetal development and a successful progress of pregnancy. However, the in vivo assessment of placental vascularization with non-invasive methods is complicated by the small size of placental terminal vessel and its complex architecture. Moreover, imaging with contrast agent is not recommended to pregnant women. Until recently, the fetal and maternal vascularization could only be evaluated through pulse Doppler of uterine arteries during pregnancy, which has little clinical value for utero-placental vascularization defects assessment. Recently, a non-invasive study, without use of contrast agent for vasculature evaluation of an organ of interest has become possible by the development of 3D Doppler angiography technique. The objective of this review was to make an inventory of its current and future applications for utero-placental vasculature quantification. The main findings of the literature on the assessment of utero-placental vascularization in physiological situation and major placental vascular dysfunction pathologies such as PE and IUGR were widely discussed.

  19. Cesarean Delivery for a Life-threatening Preterm Placental Abruption

    PubMed Central

    Okafor, II; Ugwu, EO

    2015-01-01

    Placental abruption is one of the major life-threatening obstetric conditions. The fetomaternal outcome of a severe placental abruption depends largely on prompt maternal resuscitation and delivery. A case of severe preterm placental abruption with intrauterine fetal death. Following a failed induction of labor with a deteriorating maternal condition despite resuscitation, emergency cesarean delivery was offered with good maternal outcome. Cesarean delivery could avert further disease progression and possible maternal death in cases of severe preterm placental abruption where vaginal delivery is not imminent. However, further studies are necessary before this could be recommended for routine clinical practice. PMID:27057388

  20. Prevention of Defective Placentation and Pregnancy Loss by Blocking Innate Immune Pathways in a Syngeneic Model of Placental Insufficiency.

    PubMed

    Gelber, Shari E; Brent, Elyssa; Redecha, Patricia; Perino, Giorgio; Tomlinson, Stephen; Davisson, Robin L; Salmon, Jane E

    2015-08-01

    Defective placentation and subsequent placental insufficiency lead to maternal and fetal adverse pregnancy outcome, but their pathologic mechanisms are unclear, and treatment remains elusive. The mildly hypertensive BPH/5 mouse recapitulates many features of human adverse pregnancy outcome, with pregnancies characterized by fetal loss, growth restriction, abnormal placental development, and defects in maternal decidual arteries. Using this model, we show that recruitment of neutrophils triggered by complement activation at the maternal/fetal interface leads to elevation in local TNF-α levels, reduction of the essential angiogenic factor vascular endothelial growth factor, and, ultimately, abnormal placentation and fetal death. Blockade of complement with inhibitors specifically targeted to sites of complement activation, depletion of neutrophils, or blockade of TNF-α improves spiral artery remodeling and rescues pregnancies. These data underscore the importance of innate immune system activation in the pathogenesis of placental insufficiency and identify novel methods for treatment of pregnancy loss mediated by abnormal placentation.

  1. Haplotype structures and functional polymorphic variants of the drug target enzyme aromatase (CYP19A1) in South Indian population.

    PubMed

    Umamaheswaran, Gurusamy; Dkhar, Steven Aibor; Kalaivani, Sekar; Anjana, Raj; Revathy, Mohan; Jaharamma, Mohammad; Shree, Kulumani Mahadevan Lakshmi; Kadambari, Dharanipragada; Adithan, Chandrasekaran

    2013-01-01

    CYP19A1 gene product aromatase (CYP19A1) is a 58-kDa protein and belongs to the member of the cytochrome P450 superfamily, which facilitates the bioconversion of estrogens from androgens. Single-nucleotide polymorphisms (SNPs) of CYP19A1 affect the activity of the enzyme and have been implicated in the association of estrogen-dependent disease, prognosis, therapeutic efficacy, and toxicity of third-generation aromatase inhibitors (AIs). Based on ethnicity, the frequency distribution of CYP19A1 alleles will differ, and until now, no data are available for Indians. Using qRT-PCR with TaqMan assays, the frequencies of functionally important polymorphic variants of CYP19A1 gene were determined in 163 healthy subjects of South Indian origin. The observed frequencies of the CYP19A1 minor alleles for the SNPs rs4646 (T), rs10046 (T), rs700519 (T), rs700518 (G), rs727479 (G), rs4775936 (T), rs10459592 (G), rs749292 (A), rs6493497 (T), and rs7176005 (A) are 41.1 (35.8-46.4), 20.0 (15.6-24.3), 33.7 (28.6-38.9), 17.8 (13.6-21.9), 25.8 (21.0-30.5), 19.9 (15.6-24.3), 33.7 (28.6-38.9), 24.9 (20.2-29.5), 35.9 (30.7-41.1), and 35.9 (30.7-41.1), respectively. Strong linkage disequilibrium existed between CYP19A1 SNPs, and sixteen different haplotype structures with a frequency >1% were derived from all the 10 SNPs tested. The most common being the haplotype (H1) GCTATCTGTG with a frequency of about 17.8%. Gender-specific assessment showed significant difference in the allele frequency for rs749292 (p < 0.04), and greater inter-ethnic variation was detected in the distribution of CYP19A1 variants except for rs727479. Our results could provide preliminary insight for further pharmacogenetic investigations of AIs as well as for subsequent molecular epidemiological studies on the contribution of these variants to the occurrence and development of estrogen-dependent disease in South Indians.

  2. Validation of murine and human placental explant cultures for use in sex steroid and phase II conjugation toxicology studies.

    PubMed

    Sato, Brittany L; Ward, Monika A; Astern, Joshua M; Kendal-Wright, Claire E; Collier, Abby C

    2015-02-01

    Human primary placental explant culture is well established for cytokine signaling and toxicity, but has not been validated for steroidogenic or metabolic toxicology. The technique has never been investigated in the mouse. We characterized human and mouse placental explants for up to 96 h in culture. Explant viability (Lactate dehydrogenase) and sex steroid levels were measured in media using spectrophotometry and ELISA, respectively. Expression and activities of the steroidogenic (3β-hydroxysteroid dehydrogenase, Cytochrome P45017A1, Cytochrome P45019), conjugation (UDP-glucuronosyltransferase, sulfotransferase (SULT)), and regeneration (β-glucuronidase, arylsulfatase C (ASC)) enzymes were determined biochemically in tissues with fluorimetric and spectrophotometric assays, and western blot. Explants were viable up to 96 h, but progesterone, estrone, and 17β-estradiol secretion decreased. Steroidogenic enzyme expression and activities were stable in mouse explants and similar to levels in freshly isolated tissues, but were lower in human explants than in fresh tissue (P<0.01). Human and mouse explants exhibited significantly less conjugation after 96 h, SULT was not detected in the mouse, and neither explants had active ASC, although proteins were expressed. Mouse explants may be useful for steroid biochemistry and endocrine disruption studies, but not metabolic conjugation. In contrast, human explants may be useful for studying conjugation for <48 h, but not for steroid/endocrine studies.

  3. The cytochrome p450 homepage.

    PubMed

    Nelson, David R

    2009-10-01

    The Cytochrome P450 Homepage is a universal resource for nomenclature and sequence information on cytochrome P450 ( CYP ) genes. The site has been in continuous operation since February 1995. Currently, naming information for 11,512 CYPs are available on the web pages. The P450 sequences are manually curated by David Nelson, and the nomenclature system conforms to an evolutionary scheme such that members of CYP families and subfamilies share common ancestors. The organisation and content of the Homepage are described.

  4. Aromatase inhibitors as add-on treatment for men with epilepsy.

    PubMed

    Harden, Cynthia; MacLusky, Neil J

    2005-01-01

    Manipulation of neurosteroids to treat epilepsy has been an area of active research. The effect of testosterone on brain excitability and seizure threshold has been mixed; the estradiol metabolite of testosterone increases brain excitability, while the reduced metabolite of testosterone, 3alpha-androstanediol, decreases brain excitability, likely through an action at the gamma-amino butyric acid A receptor. Therefore, the metabolites of testosterone produce opposite effects on brain excitability in seizure models. Aromatase is the enzyme for the conversion of testosterone to 17beta-estradiol. Aromatase inhibitors could decrease brain excitability by decreasing local estradiol levels and therefore, could be beneficial for the treatment of epilepsy. Aromatase inhibitors are US Food and Drug Administration-approved and have a long history of safe use in menopausal women with breast cancer. This review presents the results of using anastrazole in an open-label, add-on manner in a small group of men with epilepsy in order to improve seizures. The results suggested some effect on reduction of seizures and no side effects. Testosterone levels did increase, but not to above the normal range. Letrozole used in a single case was also beneficial for seizures. It was concluded that aromatase inhibitors may be a useful adjunct to the treatment of epilepsy, but habituation to the treatment may be limiting. Many men with epilepsy have low testosterone, and aromatase inhibition may be helpful in restoring levels to normal. Modulation of reproductive hormones by aromatase inhibition as well as enhancement of the 3alpha-androstanediol pathway may be an avenue of epilepsy treatment that would not produce sedative side effects, which is often a limiting factor with standard antiseizure medications. A further interesting result is that elevated follicle stimulating hormone and luteal stimulating hormone levels were associated with seizure reduction, suggesting that they may be a

  5. Aromatase inhibitor-induced joint pain: melatonin's role.

    PubMed

    Burk, R

    2008-12-01

    Aromatase inhibitors (AIs) enjoy increasing use in breast cancer adjuvant therapy. But the joint pain associated with AIs significantly reduces patient adherence despite the clear survival benefits of this class of drugs. Two clues point to a novel hypothesis for this unexplained symptom. First, realizing that joint pain is associated with virtually all estrogen-depleting breast cancer treatments suggests that the cause is broader than this particular class of drugs. Second, the strongly circadian nature of these symptoms suggests circadian hormone involvement. This puts new light on some existing research findings: that estrogen depletion can increase pineal melatonin, that the ability of light to suppress pineal melatonin is more variable than once thought, and that an altered melatonin cycle is associated with rheumatoid arthritis patients, where identical circadian symptoms present. It is hypothesized that when AIs decrease estrogen levels, light-induced melatonin suppression (LIMS) loses efficacy, leading to an abnormal melatonin cycle as seen in rheumatoid arthritis patients, producing (via mechanisms not yet understood) the symptoms of morning stiffness. Not all frequencies of retinal light are equally effective at suppressing pineal melatonin; most artificial lighting has less relevant spectral density than sunlight. This hypothesis predicts that some patients can suppress the circadian joint pain associated with aromatase inhibitors merely by getting sufficient hours of daily retinal sunlight. A single patient history is discussed, in which a series of treatments had no effect on AI joint pain, while extended exposure to sunlight produced a definitive elimination of symptoms the next morning. To conclusively demonstrate the role of melatonin, light-emitting diodes of an appropriate frequency were mounted on a cap for the patient to wear. If worn first thing in the morning, the cap sharply curtailed the duration of morning stiffness. If worn for a

  6. Identification of aromatase activity in rodent pituitary cell strains.

    PubMed

    Callard, G V; Petro, Z; Tashjian, A H

    1983-07-01

    To date, biochemical evidence has been presented for hypophysial aromatization in only one species, a teleost fish, although the pituitary glands of several mammals have been reported to be aromatase negative. To reinvestigate this problem, established clonal strains of rodent pituitary cells (GH3, GH4C1, and AtT20/D16) were incubated at 37 C for 6-48 h in serum-less medium containing [7-3H]androstenedione. Radiolabeled metabolites were isolated by solvent extraction, thin layer chromatography, and phenolic partition. The authenticity of the estrogenic products in both cells and incubation medium was verified by methylation and recrystallization to constant specific activity. Measurement of androgen metabolites was also validated by recrystallization of selected samples. Authentic estrone and 17 beta-estradiol were identified in cultures of the two PRL- and GH-secreting clones, and there were strain differences in the quantity of estrogen produced (GH3 greater than GH4C1). Under the same conditions, aromatization was not detectable in the ACTH-secreting line (AtT20/D16). A time-yield analysis of androgen metabolism in GH4C1 cells showed that aromatization was linear for 12 h after labeling, but that substrate was diverted mainly to 5 alpha-reducing pathways. Large amounts of highly polar metabolites accumulated 24 and 48 h after the addition of [3H]androgen, and subsequent hydrolysis revealed that these were sulfo- and glucuronoconjugates. The metabolic fate of estrogen in GH4C1 cultures was investigated indirectly by adding a radioinert estrone trap together with the radiolabeled androgen substrate and was also tested in separate cultures by adding [3H]estrone and [3H]estradiol directly. Although the two estrogens were interconverted, there was no evidence that formed or added estrogen was extensively metabolized or conjugated. We conclude that the expression of aromatase activity in hypophysial cells is not a property of all transformed lines but may be dictated

  7. The role of aromatase inhibitors in early breast cancer.

    PubMed

    Chung, Cathie T; Carlson, Robert W

    2003-04-01

    The role of hormonal therapy for the treatment of patients with early stage breast cancer has been evaluated in many studies. The results of these studies establish tamoxifen as the gold standard of hormonal therapy for the adjuvant treatment of hormone receptor-positive invasive breast cancer in pre- and postmenopausal women. Studies show tamoxifen reduces the risk of invasive breast cancer in women at increased risk for the disease, including women with ductal carcinoma in situ. Tamoxifen has adverse effects such as hot flashes, increased risk of uterine cancer in postmenopausal women, and rare occurrence of thromboembolic disease. Despite the multiple therapeutic roles of tamoxifen, alternatives are needed. Aromatase inhibitors (AI) are drugs with antiestrogenic activity. AIs function by inhibiting the peripheral conversion of adrenally synthesized androstenedione to estradiol through inhibition of the aromatase enzyme. AIs do not suppress estradiol synthesis by the ovary adequately. Therefore, AIs are effective in reducing circulating estradiol levels in postmenopausal women, but not premenopausal women. Selective nonsteroidal AIs, including anastrozole (Arimidex; AstraZeneca, Wilmington, DE) and letrozole (Femara; Novartis, East Hanover, NJ), and the steroidal AI exemestane (Aromasin; Pharmacia, Peapack, NJ) have been associated with increased specificity and improved therapeutic index compared to nonselective AIs such as aminoglutethamide. Nonsteroidal and steroidal AIs have demonstrated to be superior to megestrol acetate in second-line therapy of postmenopausal women with metastatic breast cancer, and selective nonsteroidal AIs have shown to be superior to tamoxifen in first-line therapy of postmenopausal women with metastatic breast cancer. The ATAC (Arimidex, tamoxifen, alone, or in combination) trial is the only published randomized trial comparing the efficacy of an AI to tamoxifen for the adjuvant treatment of women with early breast cancer. This large

  8. Synthesis of aromatase inhibitors and dual aromatase steroid sulfatase inhibitors by linking an arylsulfamate motif to 4-(4H-1,2,4-triazol-4-ylamino)benzonitrile: SAR, crystal structures, in vitro and in vivo activities.

    PubMed

    Bubert, Christian; Woo, L W Lawrence; Sutcliffe, Oliver B; Mahon, Mary F; Chander, Surinder K; Purohit, Atul; Reed, Michael J; Potter, Barry V L

    2008-11-01

    4-(((4-Cyanophenyl)(4H-1,2,4-triazol-4-yl)amino)methyl)phenyl sulfamate (6 a) was the first dual aromatase-sulfatase inhibitor (DASI) reported. Several series of its derivatives with various linker systems between the steroid sulfatase (STS) and the aromatase inhibitory pharmacophores were synthesised and evaluated in JEG-3 cells. The X-ray crystal structures of the aromatase inhibitors, DASI precursors 42 d and 60, and DASI 43 h were determined. Nearly all derivatives show improved in vitro aromatase inhibition over 6 a but decreased STS inhibition. The best aromatase inhibitor is 42 e (IC(50)=0.26 nM) and the best DASI is 43 e (IC(50 aromatase)=0.45 nM, IC(50 STS)=1200 nM). SAR for aromatase inhibition shows that compounds containing an alkylene- and thioether-based linker system are more potent than those that are ether-, sulfone-, or sulfonamide-based, and that the length of the linker has a limited effect on aromatase inhibition beyond two methylene units. Compounds 43 d-f were studied in vivo (10 mg kg(-1), single, p.o.). The most potent DASI is 43 e, which inhibited PMSG-induced plasma estradiol levels by 92 % and liver STS activity by 98 % 3 h after dosing. These results further strengthen the concept of designing and developing DASIs for potential treatment of hormone-related cancers.

  9. Placental/umbilical cord blood transplantation.

    PubMed

    Sirchia, G; Rebulla, P

    1999-08-01

    In this article we summarize the clinical outcome of unrelated placental/umbilical cord blood (CB) transplantation, discuss the biological characteristics of CB hematopoietic progenitor/stem cells (HPC) and balance the relative advantages and disadvantages of this therapy as compared with transplantation of other HPC sources. Moreover, we discuss CB banking programs at local, national and international levels. The data reported by the investigators of the New York Placental/Umbilical Cord Blood Program and of the Eurocord group indicate that the clinical outcome of allogeneic unrelated CB transplantation is significantly related to cell dose, being more effective in children than in adults, and is highly dependent on disease stage at transplantation. Furthermore, both studies show lower graft-versus-host disease (GvHD) frequency and severity and prolonged time intervals for platelet engraftment as compared to those of bone marrow and mobilized peripheral blood recipients. Although the data from the New York Placental/Umbilical Cord Blood Program seem to support a negative effect of HLA differences, the latter were not significantly associated with survival in the Eurocord series. Additional observations are therefore necessary to collect conclusive evidence in this regard. Currently available data show that CB contains a higher proportion of primitive HPC and that CB-HPC possess higher proliferation and expansion potentials as compared to adult bone marrow. Furthermore, there is some evidence indicating that CB-HPC are more adequate than HPC from other sources for genetic manipulation and gene therapy. Despite the significant advances in the knowledge of the biology and in the clinical use of CB, a number of problems remain unsolved, including the standardization of banking procedures and unit quality and the development of suitable protocols for transplantation of adult patients.

  10. Foetal placental blood flow in the lamb

    PubMed Central

    Faber, J. Job; Green, Thomas J.

    1972-01-01

    1. Fifteen sheep foetuses of 1·5-5·2 kg body weight were prepared with indwelling arterial and venous catheters for experimentation one to six days later. 2. Unanaesthetized foetuses were found to have mean arterial and central venous blood pressures of 40 ± 1·5 (S.E. of mean) and 2·0 ± 0·3 (S.E. of mean) mm Hg respectively, compared to intra-uterine pressure. Intra-uterine pressure was 16 ± 0·8 (S.E. of mean) mm Hg with respect to atmospheric pressure at mid-uterine level. 3. Mean placental blood flow of the foetuses was 199 ± 20 (S.E. of mean) ml./(min.kg body wt.). Mean cardiac output in eleven of the foetuses was 658 ± 102 (S.E. of mean) ml./(min.kg). 4. Mean foetal and maternal colloid osmotic pressures were 17·5 ± 0·7 (S.E. of mean) and 20·5 ± 0·6 (S.E. of mean) mm Hg respectively at 38° C. 5. Intravenous infusions into six ewes of 1·8 mole of mannitol and 0·4 mole of NaCl resulted in significant increases in foetal plasma osmolarity, sodium, potassium, and haemoglobin concentrations, without detectable transfer of mannitol to the foetal circulation. 6. In the sheep placenta there is osmotic and hydrostatic equilibration of water. As a consequence, there should be an interaction between foetal placental blood flow and foetal water exchange with the maternal circulation. It was concluded that this interaction tends to stabilize foetal placental blood flow. PMID:5039279

  11. SIRT1 positively regulates breast cancer associated human aromatase (CYP19A1) expression.

    PubMed

    Holloway, Kimberly R; Barbieri, Andreia; Malyarchuk, Svitlana; Saxena, Madhurima; Nedeljkovic-Kurepa, Ana; Cameron Mehl, Mathieu; Wang, Allison; Gu, Xin; Pruitt, Kevin

    2013-03-01

    Breast cancer remains one of the leading causes of death in women diagnosed with cancer. In breast cancer, aberrant expression of the CYP19A1 gene, which encodes the aromatase enzyme, contributes to increased intratumoral levels of estradiol. Regardless of whether this estrogen is produced by peripheral tissues or within specific subpopulations of cells within the breast tumor, it is clear that the aromatase enzymatic activity is critical for the growth of estrogen-dependent tumors. Currently, aromatase inhibitors have proven to be highly effective in blocking the growth of estrogen-dependent forms of breast cancer. CYP19A1 transcription is tightly controlled by 10 tissue-specific promoters. In breast cancer, however, aromatase transcription is driven by multiple promoters that somehow override the tissue-specific regulation of normal tissue. Here, we explore the role that the deacetylase, sirtuin-1 (SIRT1), plays in positively regulating aromatase in breast cancer. We demonstrate that the use of cambinol and the SIRT1/2 inhibitor VII, 2 small molecule inhibitors of SIRT1 and SIRT2, as well as small molecule inhibitors and small interfering RNA specific to SIRT1, all reduce the levels of aromatase mRNA. We further demonstrate that pharmacologic inhibition causes a marked reduction in aromatase protein levels. Additionally, by chromatin immunoprecipitation, we demonstrate that SIRT1 occupies the promoter regions PI.3/PII and PI.4, and its inhibition leads to increased acetylation of estrogen-related receptorα, a transcription factor that positively regulates CYP19A1 transcription in epithelial cells. Finally, we demonstrate by immunohistochemistry that SIRT1 is significantly up-regulated in invasive ductal carcinoma relative to normal tissue adjacent to tumor, further suggesting a role of SIRT1 in breast cancer. This work uncovers a new mechanism for the regulation of aromatase and provides rationale for further investigation of how the inhibition of specific

  12. Aromatase overexpression induces malignant changes in estrogen receptor α negative MCF-10A cells.

    PubMed

    Wang, J; Gildea, J J; Yue, W

    2013-10-31

    Estrogen is a risk factor of breast cancer. Elevated expression of aromatase (estrogen synthase) in breast tissues increases local estradiol concentrations and is associated with breast cancer development, but the causal relationship between aromatase and breast cancer has not been identified. Accumulating data suggest that both estrogen receptor (ER)-dependent and -independent effects are involved in estrogen carcinogenesis. We established a model by expressing aromatase in ERα- MCF-10A human breast epithelial cells to investigate ERα-independent effects of estrogen in the process of malignant transformation. Overexpression of aromatase significantly increased anchorage-independent growth. Parental- or vector-expressing MCF-10A cells did not form colonies under the same conditions. The anchorage-independent growth of MCF-10A(arom) cells can be completely abolished by pre-treatment with the aromatase inhibitor, letrozole. Neither MCF-10A(arom) nor MCF-10A(vector) cells grown in monolayer were affected by short-term exposure to estradiol. Enhanced motility is another characteristic of cellular transformation. Motility of MCF-10A(arom) cells was increased, which could be inhibited by letrozole. Increases in stem cell population in breast cancer tissues are associated with tumor recurrence and metastasis. CD44(high)/CD24(low) is a stem cell marker. We found that CD24 mRNA levels were reduced in MCF-10A(arom) cells compared with those in parental- and vector-transfected cells. By examining individual clones of MCF-10A(arom) with various aromatase activities, we found that the CD24 mRNA levels were inversely correlated with aromatase activity. The ability of MCF-10A(arom) cells to form mammospheres in the absence of serum was increased. Our results suggest that overexpression of aromatase in MCF-10A cells causes malignant transformation. Estrogen metabolite-mediated genotoxicity and induction of a stem cell/progenitor cell population are possible mechanisms. These

  13. Placental glucose dehydrogenase polymorphism in Koreans.

    PubMed

    Kim, Y J; Paik, S G; Park, H Y

    1994-12-01

    The genetic polymorphism of placental glucose dehydrogenase (GDH) was investigated in 300 Korean placentae using horizontal starch gel electrophoresis. The allele frequencies for GDH1, GDH2 and GDH3 were 0.537, 0.440 and 0.005, respectively, which were similar to those in Japanese. We also observed an anodal allele which was similar to the GDH4 originally reported in Chinese populations at a low frequency of 0.015. An additional new cathodal allele (named GDH6) was observed in the present study with a very low frequency of 0.003.

  14. Providing a Placental Transfusion in Newborns Who Need Resuscitation

    PubMed Central

    Katheria, Anup C.; Brown, Melissa K.; Rich, Wade; Arnell, Kathy

    2017-01-01

    Over the past decade, there have been several studies and reviews on the importance of providing a placental transfusion to the newborn. Allowing a placental transfusion to occur by delaying the clamping of the umbilical cord is an extremely effective method of enhancing arterial oxygen content, increasing cardiac output, and improving oxygen delivery. However, premature and term newborns who require resuscitation have impaired transitional hemodynamics and may warrant different methods to actively provide a placental transfusion while still allowing for resuscitation. In this review, we will provide evidence for providing a placental transfusion in these circumstances and methods for implementation. Several factors including cord clamping time, uterine contractions, umbilical blood flow, respirations, and gravity play an important role in determining placental transfusion volumes. Finally, while many practitioners agree that a placental transfusion is beneficial, it is not always straightforward to implement and can be performed using different methods, making this basic procedure important to discuss. We will review three placental transfusion techniques: delayed cord clamping, intact umbilical cord milking, and cut-umbilical cord milking. We will also review resuscitation with an intact cord and the evidence in term and preterm newborns supporting this practice. We will discuss perceived risks versus benefits of these procedures. Finally, we will provide key straightforward concepts and implementation strategies to ensure that placental-to-newborn transfusion can become routine practice at any institution. PMID:28180126

  15. Developmental modularity and the marsupial-placental dichotomy.

    PubMed

    Goswami, A; Weisbecker, V; Sánchez-Villagra, M R

    2009-05-15

    The contrasting evolutionary histories of marsupial and placental mammals have often been attributed to their different reproductive strategies. The speciose placentals develop mainly in utero and have radiated into diverse niches, whereas marsupials are born in a highly altricial state with immediate functional requirements and are limited in taxonomic, ecological, and morphological diversity. These differences have been tied to heterochrony, and it has been hypothesized that coordinated shifts in developmental timing occur among functionally- or developmentally related structures, such as forelimbs in marsupials. We use new ossification sequence data for 11 marsupial and 14 placental species to assess the integration of first ossification timing among skeletal elements. Although cranial elements fail to demonstrate significant coordination, marsupials and placentals differ markedly in postcranial integration. Marsupials display independent anterior and posterior developmental modules, whereas placentals show significant integration of the entire appendicular skeleton. This developmental integration of the placental postcranium is consistent with a recent study of phenotypic modularity in limbs of placental mammals, showing a potential correspondence between integration of developmental timing and of shape. The observed differences in postcranial integration between marsupials and placentals may reflect the disparate evolutionary histories of these two mammalian clades.

  16. No evidence for the in vivo activity of aromatase-inhibiting flavonoids.

    PubMed

    Saarinen, N; Joshi, S C; Ahotupa, M; Li, X; Ammälä, J; Mäkelä, S; Santti, R

    2001-09-01

    Measurements of the aromatase-inhibiting and antioxidative capacities of flavonoids in vitro showed that slight changes in flavonoid structure may result in marked changes in biological activity. Several flavonoids such as 7-hydroxyflavone and chrysin (5,7-dihydroxyflavone) were shown to inhibit the formation of 3H-17beta-estradiol from 3H-androstenedione (IC(50)<1.0 microM) in human choriocarcinoma JEG-3 cells and in human embryonic kidney cells HEK 293 transfected with human aromatase gene (Arom+HEK 293). Flavone and quercetin (3,3',4',5,7-pentahydroxyflavone) showed no inhibition (IC(50)>100 microM). None of the requirements for optimal antioxidative capacity (2,3-double bond with 4'-hydroxy group, 3-hydroxyl group, 5,7-dihydroxy structure and the orthodihydroxy structure in the B-ring) is relevant for the maximum inhibition of aromatase by flavonoids. After oral administration to immature rats at a dose of 50 mg/kg body weight, which considerably exceeds amounts found in daily human diets, neither aromatase-inhibiting nonestrogenic flavonoids, such as chrysin, nor estrogenic flavonoids, such as naringenin and apigenin, induced uterine growth or reduced estrogen- or androgen-induced uterine growth. The inability of flavonoids to inhibit aromatase and, consequently, uterine growth in short-term tests may be due to their relatively poor absorption and/or bioavailability.

  17. Theoretical Study of the Mechanism of Exemestane Hydroxylation Catalyzed by Human Aromatase Enzyme.

    PubMed

    Viciano, Ignacio; Martí, Sergio

    2016-04-07

    Human aromatase (CYP19A1) aromatizes the androgens to form estrogens via a three-step oxidative process. The estrogens are necessary in humans, mainly in women, because of the role they play in sexual and reproductive development. However, these also are involved in the development and growth of hormone-dependent breast cancer. Therefore, inhibition of the enzyme aromatase, by means of drugs known as aromatase inhibitors, is the frontline therapy for these types of cancers. Exemestane is a suicidal third-generation inhibitor of aromatase, currently used in breast cancer treatment. In this study, the hydroxylation of exemestane catalyzed by aromatase has been studied by means of hybrid QM/MM methods. The Free Energy Perturbation calculations provided a free energy of activation for the hydrogen abstraction step (rate-limiting step) of 17 kcal/mol. The results reveal that the hydroxylation of exemestane is not the inhibition stage, suggesting a possible competitive mechanism between the inhibitor and the natural substrate androstenedione in the first catalytic subcycle of the enzyme. Furthermore, the analysis of the interaction energy for the substrate and the cofactor in the active site shows that the role of the enzymatic environment during this reaction consists of a transition state stabilization by means of electrostatic effects.

  18. The vascular endothelial growth factor receptor inhibitor PTK787/ZK222584 inhibits aromatase.

    PubMed

    Banerjee, Susana; Zvelebil, Marketa; Furet, Pascal; Mueller-Vieira, Ursula; Evans, Dean B; Dowsett, Mitch; Martin, Lesley-Ann

    2009-06-01

    Endocrine therapy is well established for the treatment of breast cancer, and antiangiogenic agents are showing considerable promise. Targeting the vascular endothelial growth factor (VEGF) and estrogen receptor (ER) signaling pathways concomitantly may provide enhanced therapeutic benefit in ER-positive breast cancer. Therefore, the effects of the VEGF receptor (VEGFR) tyrosine kinase inhibitor PTK787/ZK222584 (PTK/ZK) were investigated using human breast cancer cell lines engineered to express aromatase. As expected in this system, estrogen (E2) or androstenedione induced a proliferative response and increased ER-mediated transcription in ER-positive cell lines expressing aromatase. However, surprisingly, in the presence of androstenedione, PTK/ZK suppressed both the androstenedione-stimulated proliferation and ER-mediated transcription. PTK/ZK alone and in the presence of E2 had no observable effect on proliferation or ER-mediated transcription. These effects result from PTK/ZK having previously unrecognized antiaromatase activity and PTK/ZK being a competitive aromatase inhibitor. Computer-assisted molecular modeling showed that PTK/ZK could potentially bind directly to aromatase. The demonstration that PTK/ZK inhibits aromatase and VEGFR indicates that agents cross-inhibiting two important classes of targets in breast cancer could be developed.

  19. Perinatal aromatase activity in male and female rats: effect of prenatal alcohol exposure.

    PubMed

    McGivern, R F; Roselli, C E; Handa, R J

    1988-12-01

    Fetal alcohol exposure has been shown to produce long-term feminizing and demasculinizing effects on male rat behaviors which are organizationally dependent upon perinatal androgen levels. Such exposure has previously been shown to suppress the normal surge of testosterone during the critical prenatal period. Since defeminization of male rat behavior is dependent upon estrogen derived from the aromatization of testosterone in brain, brain aromatase activity was measured during the perinatal period in males and females exposed to alcohol beginning on Day 14 of gestation. Aromatase activity was measured in whole hypothalamus of fetuses from Day 16 through 20 of gestation and in the hypothalamic preoptic area and amygdala of animals 6-12 hr postparturition. Hypothalamic aromatase activity was elevated in fetal alcohol exposed males compared to controls on Days 18 and 19 of gestation and on postnatal Day 1. No effect of prenatal alcohol exposure was found in females. A sex effect in aromatase activity in the amygdala was evident on Day 1 when activity was found to be greater in males than females. Overall, these findings indicate that fetal alcohol exposure will elevate regional brain aromatase activity in males, but not females during the perinatal period of neurobehavioral sexual differentiation.

  20. Activation of endocrine-related gene expression in placental choriocarcinoma cell lines following DNA methylation knock-down.

    PubMed

    Hogg, K; Robinson, W P; Beristain, A G

    2014-07-01

    Increasingly, placental DNA methylation is assessed as a factor in pregnancy-related complications, yet the transcriptional impact of such findings is not always clear. Using a proliferative in vitro placental model, the effect of DNA methylation loss on gene activation was evaluated at a number of genes selected for being differentially methylated in pre-eclampsia-associated placentae in vivo. We aimed to determine whether reduced DNA methylation at specific loci was associated with transcriptional changes at the corresponding gene, thus providing mechanistic underpinnings for previous clinical findings and to assess the degree of transcriptional response amongst our candidate genes. BeWo and JEG3 choriocarcinoma cells were exposed to 1 μM 5-Aza-2'-deoxycytidine (5-Aza-CdR) or vehicle control for 48 h, and re-plated and cultured for a further 72 h in normal media before cells were harvested for RNA and DNA. Bisulphite pyrosequencing confirmed that DNA methylation was reduced by ∼30-50% points at the selected loci studied in both cell lines. Gene activation, measured by qRT-PCR, was highly variable and transcript specific, indicating differential sensitivity to DNA methylation. Most notably, loss of DNA methylation at the leptin (LEP) promoter corresponded to a 200-fold and 40-fold increase in LEP expression in BeWo and JEG3 cells, respectively (P < 0.01). Transcripts of steroidogenic pathway enzymes CYP11A1 and HSD3B1 were up-regulated ∼40-fold in response to 5-Aza-CdR exposure in BeWo cells (P < 0.01). Other transcripts, including aromatase (CYP19), HSD11B2, inhibin (INHBA) and glucocorticoid receptor (NR3C1) were more moderately, although significantly, affected by loss of associated DNA methylation. These data present a mixed effect of DNA methylation changes at selected loci supporting cautionary interpretation of DNA methylation results in the absence of functional data.

  1. REPRODUCTION AND AROMATASE ACTIVITY IN THE MARINE FISH CUNNER (TAUTOGOLABROUS ADSPERSUS) EXPOSED TO ATRAZINE AND OCTYLPHENOL IN THE LABORATORY

    EPA Science Inventory

    This study was conducted to test the hypothesis that reproduction in fish is altered by exposure to endocrine-disrupting chemicals (EDCs) that modify aromatase activity. Aromatase, a product of the CYP19 gene, is the enzyme that catalyzes the conversion of the androgens androst...

  2. Development of a new class of aromatase inhibitors: Design, synthesis and inhibitory activity of 3-phenylchroman-4-one (isoflavanone) derivatives

    PubMed Central

    Bonfield, Kevin; Amato, Erica; Bankemper, Tony; Agard, Hannah; Steller, Jeffrey; Keeler, James M.; Roy, David; McCallum, Adam; Paula, Stefan; Ma, Lili

    2014-01-01

    Aromatase (CYP19) catalyzes the aromatization reaction of androgen substrates to estrogens, the last and rate-limiting step in estrogen biosynthesis. Inhibition of aromatase is a new and promising approach to treat hormone-dependent breast cancer. We present here the design and development of isoflavanone derivatives as potential aromatase inhibitors. Structural modifications were performed on the A and B rings of isoflavanones via microwave-assisted, gold-catalyzed annulation reactions of hydroxyaldehydes and alkynes. The in vitro aromatase inhibition of these compounds was determined by fluorescence-based assays utilizing recombinant human aromatase (baculovirus/insect cell-expressed). The compounds 3-(4-phenoxyphenyl)chroman-4-one (1h), 6-methoxy-3-phenylchroman-4-one (2a) and 3-(pyridin-3-yl)chroman-4-one (3b) exhibited potent inhibitory effects against aromatase with IC50 values of 2.4 μM, 0.26 μM and 5.8 μM, respectively. Docking simulations were employed to investigate crucial enzyme/inhibitor interactions such as hydrophobic interactions, hydrogen bonding and heme iron coordination. This report provides useful information on aromatase inhibition and serves as a starting point for the development of new flavonoid aromatase inhibitors. PMID:22444875

  3. Brain and gonadal aromatase as potential targets of endocrine disrupting chemicals in a model species, the zebrafish (Danio rerio).

    PubMed

    Hinfray, N; Palluel, O; Turies, C; Cousin, C; Porcher, J M; Brion, F

    2006-08-01

    Many chemicals in the aquatic environment are able to adversely affect in vitro brain and ovarian aromatase expression/activity. However, it remains to be determined if these substances elicit in vivo effect in fish. With the view to further understanding possible effects of endocrine disrupting chemicals (EDCs) on aromatase function, we first developed methods to measure brain and ovarian aromatase expression/activity in a model species, the zebrafish, and assessed the effect of estradiol (E2) and androstatrienedione (ATD), a steroidal aromatase inhibitor. We showed that CYP19b gene was predominantly expressed in the brain whereas in the ovary CYP19a mRNA level was predominant. Moreover, aromatase activities (AA) were higher in brain than in ovary. In adult zebrafish, E2 treatment had no effect on aromatase expression/activity in brain, whereas at larval stage, E2 strongly triggered CYP19b expression. In the ovaries, E2 led to a complete inhibition of both CYP19a expression and AA. Exposure to ATD led to a total inhibition of both brain and ovarian AA but had no effect on CYP19 transcripts abundance. Together, these results provide relevant knowledge concerning the characterization of aromatase in the zebrafish, and reinforce the idea that brain and ovarian aromatase are promising markers of EDCs in fish and deserve further in vivo studies.

  4. Aromatase activity in the ovary and brain of the eastern mosquitofish (Gambusia holbrooki) exposed to paper mill effluent.

    PubMed Central

    Orlando, Edward F; Davis, William P; Guillette, Louis J

    2002-01-01

    Studies have shown that female mosquitofish living downstream of a paper mill located on the Fenholloway River, Florida, have masculinized secondary sex characteristics, including altered anal fin development and reproductive behavior. Masculinization can be caused by exposure to androgens in the water or from an alteration in aromatase activity in the fish. We hypothesized that aromatase activity would be inhibited by a component(s) of the paper mill effluent. Aromatase inhibition could masculinize the hormonal profile and, subsequently, secondary sex characteristics of the exposed females. Therefore, we predicted that ovarian and brain aromatase activity would be lower in the female mosquitofish from the Fenholloway River compared with the reference site, the Econfina River. Adult females were collected and standard length, body mass, anal fin length, and segment number were measured. Ovarian and brain aromatase activity were determined using a tritiated water assay. Fenholloway females had masculinized anal fin development as indicated by an increase in the number of segments in the longest anal fin ray (p < 0.0001), yet the length of the ray did not differ between sites (p = 0.95). Fenholloway females exhibited higher ovarian (p = 0.0039) and brain (p = 0.0003) aromatase activity compared with reference site fish. These data do not support aromatase inhibition as the mechanism for masculinization, suggesting that the masculinization of the Fenholloway female mosquitofish is due to androgenic contaminants. Future studies should examine the relationship between aromatase enzyme activity and exposure to environmental androgens. PMID:12060840

  5. Management of arthralgias associated with aromatase inhibitor therapy.

    PubMed

    Thorne, C

    2007-12-01

    For the upfront adjuvant therapy of postmenopausal estrogen receptor-positive breast cancer, the third-generation aromatase inhibitors (AIS) have shown a more favourable overall risk-benefit profile than has tamoxifen. Benefits of the ais include less frequent gynecologic, cerebrovascular, and thromboembolic adverse events; greater disease-free survival; and lower tumour recurrence. Although approximately 25% of postmenopausal women with early breast cancer report experiencing symptoms of arthralgia with ai therapy, 68-month data from the Arimidex, Tamoxifen, Alone or in Combination trial showed that, compared with tamoxifen, anastrozole treatment was associated with only a modest increase in the incidence of joint symptoms. The events, which were mostly mild-to-moderate in intensity, led to treatment withdrawal in 2% of patients on anastrozole as compared with 1% in the tamoxifen arm. The symptoms and changes correlate with clinical, biochemical, and radiologic findings in symptomatic women. To determine appropriate intervention, it is therefore essential to perform a comprehensive evaluation of musculoskeletal complaints to distinguish natural menopause-related degenerative disease from AI-related effects. The present review explores the advantages of differential diagnosis with an emphasis on history and physical and musculoskeletal examination; laboratory investigations are used to corroborate or rule out clinical impressions. The transient symptoms associated with the ais are manageable with an appropriate combination of lifestyle changes, including exercise and joint protection in conjunction with pharmacologic approaches.

  6. Multimodality imaging of placental masses: a pictorial review.

    PubMed

    Jha, Priyanka; Paroder, Viktoriya; Mar, Winnie; Horowtiz, Jeanne M; Poder, Liina

    2016-12-01

    Placental masses are uncommonly identified at the time of obstetric ultrasound evaluation. Understanding the pathologies presenting as placental masses is key for providing a differential diagnosis and guiding subsequent management, which may include additional imaging with magnetic resonance (MR) imaging. Potential benign entities include chorioangiomas and teratomas. Larger chorioangiomas can cause fetal cardiovascular issues from volume overload. Placental mesenchymal dysplasia has an association with fetal anomalies and detailed fetal evaluation should be performed when it is suspected. Identifying other cystic masses such as partial and complete moles is crucial to prevent erroneous pregnancy termination. This review addresses normal imaging appearance of the placenta on ultrasound and MR imaging and describes various trophoblastic and nontrophoblastic placental masses. Potential placental mass mimics including uterine contractions and thrombo-hematomas are also presented.

  7. Ethical aspects of banking placental blood for transplantation.

    PubMed

    Sugarman, J; Reisner, E G; Kurtzberg, J

    1995-12-13

    Transplantation of blood cells harvested from the umbilical cord immediately after birth has been effective in repopulating the bone marrow. These placental blood transplantations may be safer than conventional bone marrow transplantations and may suspend the need to harvest bone marrow, a process fraught with difficulties. Further understanding and advancement of this emerging technology require developing large banks of placental blood. In this article, we examine some of the ethical issues associated with placental blood banking, including (1) questions about ownership of the tissue, (2) the necessity and nature of obtaining informed consent from parents for harvesting placental blood and the information-gathering process associated with it, (3) obligations to notify parents and children of the results of medical testing for infectious diseases and genetic information, (4) matters of privacy and confidentiality related to such information, and (5) the need for fair and equitable harvesting of and access to placental blood.

  8. Characterization of aromatase binding agents from the dichloromethane extract of Corydalis yanhusuo using ultrafiltration and liquid chromatography tandem mass spectrometry.

    PubMed

    Shi, Jing; Zhang, Xiaoyu; Ma, Zhongjun; Zhang, Min; Sun, Fang

    2010-05-14

    Aromatase represents an important target for the treatment of hormone-dependent breast cancer. In the present study, nine alkaloids from the dichloromethane extract of Corydalis yanhusuo were identified by liquid chromatography tandem mass spectrometry (LC-MS/MS) and tested for their aromatase binding activities using an ultrafiltration LC-MS method by investigating the differences of peak areas of compounds before and after incubations with aromatase. It was demonstrated that the quaternary protoberberine alkaloids and the tertiary protoberberine alkaloids exhibited potent aromatase binding activities. The quaternary ammonium group and the methyl group at C-13 position of tertiary protoberberine alkaloids might be necessary for the activity. The findings should provide guidance for the discovery of potential aromatase inhibitors from natural products.

  9. Protein profiling of preeclampsia placental tissues.

    PubMed

    Shu, Chang; Liu, Zitao; Cui, Lifeng; Wei, Chengguo; Wang, Shuwen; Tang, Jian Jenny; Cui, Miao; Lian, Guodong; Li, Wei; Liu, Xiufen; Xu, Hongmei; Jiang, Jing; Lee, Peng; Zhang, David Y; He, Jin; Ye, Fei

    2014-01-01

    Preeclampsia is a multi-system disorder involved in pregnancy without an effective treatment except delivery. The precise pathogenesis of this complicated disorder is still not completely understood. The objective of this study is to evaluate the alterations of protein expression and phosphorylations that are important in regulating placental cell function in preterm and term preeclampsia. Using the Protein Pathway Array, 38 proteins in placental tissues were found to be differentially expressed between preterm preeclampsia and gestational age matched control, while 25 proteins were found to be expressed differentially between term preeclampsia and matched controls. Among these proteins, 16 proteins and their associated signaling pathways overlapped between preterm and term preeclampsia, suggesting the common pathogenesis of two subsets of disease. On the other hand, many proteins are uniquely altered in either preterm or term preeclampsia and correlated with severity of clinical symptoms and outcomes, therefore, providing molecular basis for these two subsets of preeclampsia. Furthermore, the expression levels of some of these proteins correlated with neonatal small for gestational age (PAI-1 and PAPP-A) and adverse outcomes (Flt-1) in women with preterm preeclampsia. These proteins could potentially be used as candidate biomarkers for predicting outcomes of preeclampsia.

  10. Confined placental mosaicisms and uniparental disomy

    SciTech Connect

    Kalousek, D.K.; Langlois, S.; Harrison, K.J.

    1994-09-01

    Approximately 2% of pregnancies studied with chorionic villous sampling (CVS) show confined placental mosaicism (CPM) which persists to term in 50-70% of cases. An increased frequency of complications, such as intrauterine fetal growth restriction or intrauterine death, is observed in these pregnancies. As trisomic zygote rescue is a common mechanism responsible for CPM, fetal uniparental disomy (UPD), resulting from the loss of the extra trisomic chromosome in the embryonic stem cells, would be expected to occur in a proportion of pregnancies with CPM. We have studied 27 pregnancies with CPM involving trisomies for chromosomes 2, 7, 9, 10, 12, and 16 for involvement of specific cell lineage(s) and levels of mosaicism in term placentas. Also, DNA from the parents and infant was analyzed for UPD or biparental disomy (BPD). Five infants with UPD for chromosome 16 and one infant with UPD for chromosome 7 were detected. All other infants showed BPD for the chromosome involved in CPM. For trisomy 16 mosaic gestations, a close correlation between high levels of trisomic cells in placenta and intrauterine fetal growth restriction has been found irrespective of the type of disomy present in the infant. The effect of other trisomies (2, 7, 9, 10, 12) on placental function appears to be similar, but the low numbers of pregnancies studied and lack of detection of UPD for chromosomes 2, 9, 10 and 12 does not allow a definitive conclusion.

  11. Dynamics of Aromatase and Physiological Indexes in Male Fish as Potential Biomarkers of Anthropogenic Pollution.

    PubMed

    Guyón, N F; Roggio, M A; Amé, M V; Wunderlin, D A; Bistoni, M A

    2016-11-01

    Endocrine disruption on aquatic wildlife is being increasingly reported, and the changes in gene aromatase expression are used as indicators. However, natural fluctuations in brain and gonadal aromatase expression and physiological indexes have not been previously measured in a fish species (Jenynsia multidentata) throughout a complete reproductive cycle, nor the biological effects of anthropogenic inputs on these responses. Accordingly, males were monthly collected over a year in both, a reference and a contaminated site. Physicochemical analyses of water samples were done and reflected a strong anthropogenic impact. Brain aromatase fluctuates along the reproductive cycle of this species and, noticeably, the increase of brain gene expression begins with a 1 month delay in the contaminated site. This mismatch is also evidenced for testes weight. Hepatosomatic index also revealed adverse effects in the polluted site. In turn, the alterations observed in biological responses could be affecting the reproduction of this fish species.

  12. Lichen sclerosus in a breast cancer survivor on an aromatase inhibitor: a case report.

    PubMed

    Potter, Jennifer E; Moore, Kendra A

    2013-04-01

    Lichen sclerosus is a commonly misdiagnosed disease that is characterized by thinned, hypopigmented, crinkled skin that often forms a figure-eight shape around the vaginal and anal openings. We present a case of advanced lichen sclerosus in a 53-year-old female patient prescribed a nonsteroidal aromatase inhibitor after the excision of a breast cancer tumor. We present a diagnostic approach to lichen sclerosus by recognizing its common figure-eight pattern, and we review the known causes and treatment of lichen sclerosus. Research has shown that lichen sclerosus is more common in low estrogen states, and thus it is logical that aromatase inhibitors could increase a patient's risk for developing this disease. We therefore propose that all patients prescribed aromatase inhibitors undergo regular vulvo-vaginal exams to rule out lichen sclerosus and other hypoestrogen-related vulvo-vaginal problems.

  13. Telencephalic aromatase but not a song circuit in a sub-oscine passerine, the golden collared manakin (Manacus vitellinus).

    PubMed

    Saldanha, C J; Schultz, J D; London, S E; Schlinger, B A

    2000-06-01

    In oscine passerines, the telencephalon expresses high levels of the estrogen synthetic enzyme aromatase. In contrast, forebrain aromatase is limited to low levels at discrete limbic loci in non-passerines. The function of forebrain aromatase in oscines is unknown, however, estrogen-sensitive elements of the telencephalic song circuit (an oscine characteristic) may be influenced by local aromatization. Very few studies have investigated the neuroendocrine characteristics of sub-oscine passerines. Species of this passerine sub-order are taxonomically similar to oscines, but do not appear to learn how to sing as oscines, and show no evidence of a song circuit. The neural expression of aromatase in these birds is unknown. We asked whether the golden-collared manakin, a sub-oscine, (a) showed evidence of a song circuit, and (b) expressed aromatase in the telencephalon at high levels like the zebra finch (oscine passerine) or at low levels like the quail (non-passerine). Nissl stains and immunocytochemistry for microtubule associated proteins showed no evidence of a song circuit in manakins of either sex, whereas both techniques delineate all song nuclei in the zebra finch. However, biochemical and immunocytochemical measures reveal that in the manakin, several telencephalic loci, including the hippocampus, caudomedial neostriatum, nucleus taeniae, and the lateral neostriatum express aromatase. Assays run in parallel show low to undetectable levels of aromatase in the telencephalon of the quail (nonpasserine) and abundant levels in the zebra finch (oscine passerine), suggesting a dissociation between the presence of a song circuit and forebrain aromatase expression in this sub-oscine. These data suggest that forebrain aromatase may have evolved in sub-oscine songbirds before the evolution of a song circuit and singing behavior in oscines. Alternatively, forebrain aromatase may serve functions distinct from singing behavior.

  14. HER-2/neu x aromatase double transgenic mice model: the effects of aromatase overexpression on mammary tumorigenesis.

    PubMed

    Tekmal, Rajeshwar Rao; Nair, Hareesh B; Perla, Rao P; Kirma, Nameer

    2007-01-01

    A majority of breast cancers are hormone-responsive, and require estrogen for growth, and respond to hormonal therapy that blocks estrogen receptor action. Breast tumors with low levels of or completely lacking estrogen receptor fail to respond to antiestrogen therapy yet require estrogen for tumor initiation. To address the importance of local estrogen in oncogene-mediated breast tumorigenesis, we have crossed MMTV-aromatase with MMTV-HER2/neu and examined the incidence of breast cancer in double transgenic mice in comparison with parental strains. Double transgenic mice show normal mammary development and express both transgenes at similar levels to that of parental strains. Tumor incidence in double transgenic mice (<5%) decreased compared to HER2/neu mice (>65%). In addition to a significant decrease in tumorigenesis, these mice expressed ERalpha as well as high levels of ERbeta along with decreased levels of cyclin D1 and phosphorylated pRb among other changes. Furthermore, experiments using THC (ERalpha-agonist and ERbeta-antagonist) clearly demonstrate the critical role of ERbeta in HER2/neu-mediated tumorigenesis. These studies provide the first genetic evidence that estrogen receptor, mainly ERbeta than ERalpha and its dependent changes play an important role in regulating mammary tumorigenesis. These findings provide further evidence for development and testing of novel therapeutic approaches based on selective regulation of estrogen receptors (ERalpha and beta)-dependent actions for the treatment and prevention of breast cancers.

  15. Coulometric and spectroscopic analysis of the purified cytochrome d complex of Escherichia coli: evidence for the identification of "cytochrome a1" as cytochrome b595.

    PubMed

    Lorence, R M; Koland, J G; Gennis, R B

    1986-05-06

    Coulometric and spectroscopic analyses were performed on the three cytochrome components (cytochrome d, cytochrome b558, and the cytochrome previously described as cytochrome a1) of the purified cytochrome d complex, a terminal oxidase of the Escherichia coli aerobic respiratory chain. On the basis of heme extraction, spectroscopic, and coulometric data, the "cytochrome a1" component was identified as a b-type cytochrome: cytochrome b595. The pyridine hemochromogen technique revealed the presence of two molecules of protoheme IX per cytochrome d complex. This quantity of protoheme IX fully accounted for the sum of the cytochrome b558 and cytochrome b595 components as determined coulometrically. The renaming of cytochrome a1 as cytochrome b595 was further indicated by the lack of any heme a in the complex and by its resolved reduced-minus-oxidized spectrum. The latter was found to be similar to that of cytochrome c peroxidase, which contains protoheme IX. Coulometric titrations and carbon monoxide binding titrations revealed that there are two molecules of cytochrome d per complex. A convenient measurement of the amount of cytochrome b558 was found to be the beta-band at 531 nm since cytochrome b558 was observed to be the only component of the cytochrome d complex with a peak at this wavelength. By use of this method and the extinction coefficient for the purified cytochrome b558, it was estimated that there is one molecule of cytochrome b595 and one of cytochrome b558 per cytochrome complex.

  16. Azole fungicides affect mammalian steroidogenesis by inhibiting sterol 14 alpha-demethylase and aromatase.

    PubMed

    Zarn, Jürg A; Brüschweiler, Beat J; Schlatter, Josef R

    2003-03-01

    Azole compounds play a key role as antifungals in agriculture and in human mycoses and as non-steroidal antiestrogens in the treatment of estrogen-responsive breast tumors in postmenopausal women. This broad use of azoles is based on their inhibition of certain pathways of steroidogenesis by high-affinity binding to the enzymes sterol 14-alpha-demethylase and aromatase. Sterol 14-alpha-demethylase is crucial for the production of meiosis-activating sterols, which recently were shown to modulate germ cell development in both sexes of mammals. Aromatase is responsible for the physiologic balance of androgens and estrogens. At high doses, azole fungicides and other azole compounds affect reproductive organs, fertility, and development in several species. These effects may be explained by inhibition of sterol 14-alpha-demethylase and/or aromatase. In fact, several azole compounds were shown to inhibit these enzymes in vitro, and there is also strong evidence for inhibiting activity in vivo. Furthermore, the specificity of the enzyme inhibition of several of these compounds is poor, both with respect to fungal versus nonfungal sterol 14-alpha-demethylases and versus other P450 enzymes including aromatase. To our knowledge, this is the first review on sterol 14-alpha-demethylase and aromatase as common targets of azole compounds and the consequence for steroidogenesis. We conclude that many azole compounds developed as inhibitors of fungal sterol 14-alpha-demethylase are inhibitors also of mammalian sterol 14-alpha-demethylase and mammalian aromatase with unknown potencies. For human health risk assessment, data on comparative potencies of azole fungicides to fungal and human enzymes are needed.

  17. Making males from females: the effects of aromatase inhibitors on a parthenogenetic species of whiptail lizard.

    PubMed

    Wennstrom, K L; Crews, D

    1995-09-01

    The parthenogenetic whiptail lizard Cnemidophorus uniparens provides a good model for the study of sex determination and sexual differentiation because genetic variation is minimal and all unmanipulated embryos will develop as females. Thus any deviation from the established course of development can be identified as a treatment effect. Previous work has shown that early prenatal treatment with CGS16949A, a nonsteroidal aromatase inhibitor, causes hatchlings to develop as males. The present study explores more fully the effects of dosage and timing of application of CGS16949A and examines the sex-reversing potential of CGS20267, a new and reputedly more potent aromatase inhibitor. Eggs were treated with a range of dosages of the aromatase inhibitors. Hatchlings that received 1 microgram or more of either inhibitor were all male, while those that received 0.1 microgram or less were all female. No difference in potency between the two compounds was detected. Animals treated with 100 micrograms of CGS16949A on Day 20 of incubation or later were all female, while those treated on Day 5 were all male. Seven sex-reversed male parthenogens have been raised to sexual maturity. The animals appear similar morphologically and behaviorally to males of the sexually reproducing whiptail species. Spermatogenesis and spermiogenesis have been confirmed by histological examination of the testes and by postcopulatory cloacal swabs. Application of aromatase inhibitors has been shown to sex-reverse both avian and reptilian species. In mammals, the male-determining gene of the Y chromosome (SRY) may code for an intrinsic aromatase inhibitor. Studies show the gene's product has a binding domain which recognizes regulatory elements in the promoter of the aromatase gene.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Azole fungicides affect mammalian steroidogenesis by inhibiting sterol 14 alpha-demethylase and aromatase.

    PubMed Central

    Zarn, Jürg A; Brüschweiler, Beat J; Schlatter, Josef R

    2003-01-01

    Azole compounds play a key role as antifungals in agriculture and in human mycoses and as non-steroidal antiestrogens in the treatment of estrogen-responsive breast tumors in postmenopausal women. This broad use of azoles is based on their inhibition of certain pathways of steroidogenesis by high-affinity binding to the enzymes sterol 14-alpha-demethylase and aromatase. Sterol 14-alpha-demethylase is crucial for the production of meiosis-activating sterols, which recently were shown to modulate germ cell development in both sexes of mammals. Aromatase is responsible for the physiologic balance of androgens and estrogens. At high doses, azole fungicides and other azole compounds affect reproductive organs, fertility, and development in several species. These effects may be explained by inhibition of sterol 14-alpha-demethylase and/or aromatase. In fact, several azole compounds were shown to inhibit these enzymes in vitro, and there is also strong evidence for inhibiting activity in vivo. Furthermore, the specificity of the enzyme inhibition of several of these compounds is poor, both with respect to fungal versus nonfungal sterol 14-alpha-demethylases and versus other P450 enzymes including aromatase. To our knowledge, this is the first review on sterol 14-alpha-demethylase and aromatase as common targets of azole compounds and the consequence for steroidogenesis. We conclude that many azole compounds developed as inhibitors of fungal sterol 14-alpha-demethylase are inhibitors also of mammalian sterol 14-alpha-demethylase and mammalian aromatase with unknown potencies. For human health risk assessment, data on comparative potencies of azole fungicides to fungal and human enzymes are needed. PMID:12611652

  19. Androgen metabolism in oyster Crassostrea gigas: evidence for 17beta-HSD activities and characterization of an aromatase-like activity inhibited by pharmacological compounds and a marine pollutant.

    PubMed

    Le Curieux-Belfond, O; Moslemi, S; Mathieu, M; Séralini, G E

    2001-10-01

    The annual reproductive cycle of oyster Crassostrea gigas depends on environmental factors, but its endocrine regulations are still unknown. Sexual steroids play important roles at this level in vertebrates, and some estradiol effects have been described in invertebrates such as bivalve mollusks. To question these roles in invertebrates, we studied androgen metabolism in C. gigas. Incubations of tissue homogenates with 14C-steroids such as androstenedione (A), testosterone (T), estrone (E1) and estradiol (E2), followed by TLC and HPLC, provide evidence for 17beta-hydroxysteroid dehydrogenases (17beta-HSDs, conversions of A into T, T into A, E1 into E2 and E2 into E1) and aromatase-like (A into E1) activities. The latter activity was further characterized by tritiated water release assay; it was time- and temperature-dependent. Furthermore, this oyster aromatase-like activity was inhibited by 4-hydroxyandrostenedione (IC(50) 0.456 microM) and by other pharmacological compounds including specific cytochrome P450 inhibitors (MR20494, miconazole) and a marine pollutant (tributyltin).

  20. Ontogenesis of gonadal aromatase gene expression in atlantic silverside (Menidia menidia) populations with genetic and temperature-dependent sex determination.

    PubMed

    Duffy, Tara A; Picha, Matthew E; Won, Eugene T; Borski, Russell J; McElroy, Anne E; Conover, David O

    2010-08-01

    Cytochrome P450 aromatase (P450arom), an enzyme that converts testosterone to 17beta-estradiol, is an important mediator of sex determination in teleosts with genetic sex determination (GSD) and temperature-dependent sex determination (TSD). We compared the ontogenetic expression of P450arom in two populations of Atlantic silversides, Menidia menidia, which exhibit TSD (South Carolina) or GSD (Nova Scotia, Canada) using quantitative, real-time polymerase chain reaction (qRT-PCR). Embryos and newly hatched larvae were reared at an intermediate sex ratio-producing temperature (21 degrees C), and older larvae and juveniles were reared at temperatures that feminize (15 degrees C) and masculinize (28 degrees C) to assess the temperature response of P450arom during development. Before sex determination, embryos and newly-hatched larvae displayed negligible P450arom expression, indicating minimal upregulation of this gene before sex determination. Gene expression increased in both populations during sex differentiation. Nova Scotia fish with GSD exhibited presumptive male- and female-like expression levels during early sex differentiation that were not influenced by temperature. South Carolina fish displayed low levels of expression at 28 degrees C with significantly heightened expression in some individuals at 15 degrees C, indicating that P450arom is temperature sensitive in the population with TSD. Populations also differed in the timing and maximal levels of P450arom expression, with fish from Nova Scotia exhibiting both the highest and earliest increase in expression in presumptive females. Our results support the hypothesis that P450arom is involved in female sex differentiation in this species, but is only responsive to temperature in M. menidia populations that exhibit TSD.

  1. The Cytochrome P450 Homepage

    PubMed Central

    2009-01-01

    The Cytochrome P450 Homepage is a universal resource for nomenclature and sequence information on cytochrome P450 (CYP) genes. The site has been in continuous operation since February 1995. Currently, naming information for 11,512 CYPs are available on the web pages. The P450 sequences are manually curated by David Nelson, and the nomenclature system conforms to an evolutionary scheme such that members of CYP families and subfamilies share common ancestors. The organisation and content of the Homepage are described. PMID:19951895

  2. IFPA meeting 2015 workshop report I: placental mitochondrial function, transport systems and epigenetics.

    PubMed

    Bianco-Miotto, T; Blundell, C; Buckberry, S; Chamley, L; Chong, S; Cottrell, E; Dawson, P; Hanna, C; Holland, O; Lewis, R M; Moritz, K; Myatt, L; Perkins, A V; Powell, T; Saffery, R; Sferruzzi-Perri, A; Sibley, C; Simmons, D; O'Tierney-Ginn, P F

    2016-12-01

    Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2015 there were twelve themed workshops, three of which are summarized in this report. These workshops covered areas of placental regulation and nutrient handling: 1) placental epigenetics; 2) placental mitochondrial function; 3) placental transport systems.

  3. Aromatase, estrone sulfatase, and 17β-hydroxysteroid dehydrogenase: structure-function studies and inhibitor development.

    PubMed

    Hong, Yanyan; Chen, Shiuan

    2011-07-04

    Aromatase, estrone sulfatase, and 17β-hydroxysteroid dehydrogenase type 1 are involved in the key steps of 17β-estradiol biosynthesis. Structure-function studies of aromatase, estrone sulfatase and 17β-hydroxysteroid dehydrogenase type 1 are important to evaluate the molecular basis of the interaction between these enzymes and their inhibitors. Selective and potent inhibitors of the three enzymes have been developed as antiproliferative agents in hormone-dependent breast carcinoma. New treatment strategies for hormone-dependent breast cancer are discussed.

  4. MR 20492 and MR 20494: two indolizinone derivatives that strongly inhibit human aromatase.

    PubMed

    Auvray, P; Sourdaine, P; Moslemi, S; Séralini, G E; Sonnet, P; Enguehard, C; Guillon, J; Dallemagne, P; Bureau, R; Rault, S

    1999-01-01

    In this study, we describe the synthesis of a new family of indolizinone derivatives designed to fit an extrahydrophobic pocket within the active site of aromatase and to strongly inhibit human aromatase. This could help improve the specificity of the inhibitors. Equine aromatase, very well characterized biochemically, is used as a comparative model. Indeed, in a previous comparison between both human and equine aromatases, we described the importance of the interaction between the inhibitor and this pocket for the indane derivative MR 20814. MR 20492 and MR 20494 are more potent inhibitors of human aromatase (Ki/Km: 1.0+/-0.3 and 0.5+/-0.3, respectively). The Ki/Km for MR 20494 is slightly higher than that obtained for fadrozole (0.1+/-0.0) and Ki/Km for both indolizinone derivatives are lower than those obtained for 4-hydroxyandrostenedione (1.9+/-0.8) and MR 20814 (8.1+/-.7). These new compounds are not enzyme inactivators. Moreover, as indicated by the higher Ki/Km values obtained with equine enzyme (9.0+/-0.6 and 6.1+/-1.6 for MR 20492 and MR 20494, respectively), both human and equine aromatase active sites appear to be structurally different. Difference absorption spectra study (350-500 nm) revealed that MR20492 and MR20494 were characterized by a combination of type-I and -II spectra with both enzymes. This result could be due to the isomerization of the molecule in polar solvent (Z and E forms). The evaluation of these new molecules, as well as 4-hydroxyandrostenedione and fadrozole, on aromatase activity in transfected 293 cell cultures evidenced a strong inhibition (IC50: 0.20+/-0.03 microM, 0.20+/-0.02 microM and 0.50+/-0.40 microM for MR 20494, fadrozole and 4-OHA, respectively) except for MR 20492 (3.9+/-0.9 microM) and MR 20814 (10.5+/-0.6 microM). These results proved that these molecules formed part of a promising family of potent inhibitors and that they penetrate 293 cells, without evidencing any cytotoxicity in Hela cells with MTT assay. This is

  5. Early Dexamethasone Treatment Induces Placental Apoptosis in Sheep

    PubMed Central

    Meng, Wenbin; Shang, Hongkai; Li, Shaofu; Sloboda, Deborah M.; Ehrlich, Loreen; Lange, Karolin; Xu, Huaisheng; Henrich, Wolfgang; Dudenhausen, Joachim W.; Plagemann, Andreas; Newnham, John P.; Challis, John R. G.

    2015-01-01

    Glucocorticoid treatment given in late pregnancy in sheep resulted in altered placental development and function. An imbalance of placental survival and apoptotic factors resulting in an increased rate of apoptosis may be involved. We have now investigated the effects of dexamethasone (DEX) in early pregnancy on binucleate cells (BNCs), placental apoptosis, and fetal sex as a determinant of these responses. Pregnant ewes carrying singleton fetuses (n = 105) were randomized to control (n = 56, 2 mL saline/ewe) or DEX treatment (n = 49, intramuscular injections of 0.14 mg/kg ewe weight per 12 hours over 48 hours) at 40 to 41 days of gestation (dG). Placentomes were collected at 50, 100, 125, and 140 dG. At 100 dG, DEX in females reduced BNC numbers, placental antiapoptotic (proliferating cell nuclear antigen), and increased proapoptotic factors (Bax, p53), associated with a temporarily decrease in fetal growth. At 125 dG, BNC numbers and apoptotic markers were restored to normal. In males, ovine placental lactogen-protein levels after DEX were increased at 50 dG, but at 100 and 140 dG significantly decreased compared to controls. In contrast to females, these changes were independent of altered BNC numbers or apoptotic markers. Early DEX was associated with sex-specific, transient alterations in BNC numbers, which may contribute to changes in placental and fetal development. Furthermore, in females, altered placental apoptosis markers may be involved. PMID:25063551

  6. Placental corticotrophin-releasing hormone, local effects and fetomaternal endocrinology.

    PubMed

    King, B R; Nicholson, R C; Smith, R

    2001-12-01

    The human placenta produces corticotrophin-releasing hormone (CRH) in exponentially increasing amounts during pregnancy with peak levels during labour. CRH in human pregnancy appears to be involved in many aspects of pregnancy including placental bloodflow, placental prostaglandin production, myornetrial function, fetal pituitary and adrenal function and the maternal stress axis. Since fetal cortisol levels are associated with pulmonary development and maturity, placental CRH may have an indirect role in fetal development.Although the precise role of placental CRH in the regulation of gestational length and timing of parturition is unclear it appears to be involved in a placental clock. While glucocorticoids inhibit hypothalamic CRH production they stimulate CRH gene expression in the placenta.This difference may allow the fetal and maternal stress axes to influence this placental clock.Maternal CRH levels are elevated in many pathological conditions of pregnancy where fetal well-being is compromised, and in these situations it may act to maintain a stable intrauterine environment. Therefore, CRH appears to link placental function, maternal well-being, fetal well-being and fetal development to the duration of gestation and the timing of parturition.

  7. Placental exosomes in normal and complicated pregnancy.

    PubMed

    Mitchell, Murray D; Peiris, Hassendrini N; Kobayashi, Miharu; Koh, Yong Q; Duncombe, Gregory; Illanes, Sebastian E; Rice, Gregory E; Salomon, Carlos

    2015-10-01

    While there is considerable contemporary interest in elucidating the role of placenta-derived extracellular vesicles in normal and complicated pregnancies and their utility as biomarkers and therapeutic interventions, progress in the field is hindered by a lack of standardized extracellular vesicle taxonomy and isolation protocols. The term "extracellular vesicle" is nonspecific and refers to all membrane-bound vesicles from nanometer to micrometer diameters and of different biogenic origins. To meaningfully ascribe biological function and/or diagnostic and therapeutic utility to extracellular vesicles, and in particular exosomes, greater specificity and vesicle characterization is required. The current literature relating to exosome biology must be interpreted in this context. Exosomes are a subtype of extracellular vesicle that are specifically defined by an endosomal biogenesis and particle size (40-120 nm) and density (1.13-1.19 g/mL(-1)). Exosomes are specifically package with signaling molecules (including protein, messenger RNA, microRNA, and noncoding RNA) and are released by exocytosis into biofluid compartments. Exosomes regulate the activity of both proximal and distal target cells, including translational activity, angiogenesis, proliferation, metabolism, and apoptosis. As such, exosomal signaling represents an integral pathway mediating intercellular communication. During pregnancy, the placenta releases exosomes into the maternal circulation from as early as 6 weeks of gestation. Release is regulated by factors that include both oxygen tension and glucose concentration and correlates with placental mass and perfusion. The concentration of placenta-derived exosomes in maternal plasma increases progressively during gestation. Exosomes isolated from maternal plasma are bioactive in vitro and are incorporated into target cells by endocytosis. While the functional significance of placental exosomes in pregnancy remains to be fully elucidated, available

  8. Developmental programming: impact of testosterone on placental differentiation

    PubMed Central

    Beckett, EM; Astapova, O; Steckler, TL; Veiga-Lopez, A; Padmanabhan, V

    2014-01-01

    Gestational testosterone (T) treatment causes maternal hyperinsulinemia, intra-uterine growth retardation (IUGR), low birth weight, and adult reproductive and metabolic dysfunctions. Sheep models of IUGR demonstrate placental insufficiency as an underlying cause of IUGR. Placental compromise is likely the cause of fetal growth retardation in gestational T-treated sheep. This study tested if T excess compromises placental differentiation by its androgenic action and/or via altered insulin sensitivity. A comparative approach of studying gestational T (aromatizable androgen) against dihydrotestosterone (DHT; non-aromatizable androgen) or T plus androgen antagonist, flutamide, was used to determine whether the effects of T in placental differentiation were programmed by its androgenic actions. Co-treatment of testosterone with the insulin sensitizer, rosiglitazone, was used to establish whether the effects of gestational T on placentome differentiation involved compromised insulin sensitivity. Parallel cohorts of pregnant females were maintained for lambing and the birth weight of their offspring was recorded. Placental studies were conducted on days 65, 90, or 140 of gestation. Results indicated that 1) gestational T treatment advances placental differentiation, evident as early as day 65 of gestation, and culminates in low birth weight, 2) placental advancement is facilitated at least in part by androgenic actions of T and is not a function of disrupted insulin homeostasis, and 3) placental advancement, while helping to increase placental efficiency, was insufficient to prevent IUGR and low birth weight female offspring. Findings from this study may be of relevance to women with PCOS, whose reproductive and metabolic phenotype is captured by the gestational T-treated offspring. PMID:24840528

  9. Developmental programing: impact of testosterone on placental differentiation.

    PubMed

    Beckett, E M; Astapova, O; Steckler, T L; Veiga-Lopez, A; Padmanabhan, V

    2014-08-01

    Gestational testosterone treatment causes maternal hyperinsulinemia, intrauterine growth retardation (IUGR), low birth weight, and adult reproductive and metabolic dysfunctions. Sheep models of IUGR demonstrate placental insufficiency as an underlying cause of IUGR. Placental compromise is probably the cause of fetal growth retardation in gestational testosterone-treated sheep. This study tested whether testosterone excess compromises placental differentiation by its androgenic action and/or via altered insulin sensitivity. A comparative approach of studying gestational testosterone (aromatizable androgen) against dihydrotestosterone (non-aromatizable androgen) or testosterone plus androgen antagonist, flutamide, was used to determine whether the effects of testosterone on placental differentiation were programed by its androgenic actions. Co-treatment of testosterone with the insulin sensitizer, rosiglitazone, was used to establish whether the effects of gestational testosterone on placentome differentiation involved compromised insulin sensitivity. Parallel cohorts of pregnant females were maintained for lambing and the birth weight of their offspring was recorded. Placental studies were conducted on days 65, 90, or 140 of gestation. Results indicated that i) gestational testosterone treatment advances placental differentiation, evident as early as day 65 of gestation, and culminates in low birth weight, ii) placental advancement is facilitated at least in part by androgenic actions of testosterone and is not a function of disrupted insulin homeostasis, and iii) placental advancement, while helping to increase placental efficiency, was insufficient to prevent IUGR and low-birth-weight female offspring. Findings from this study may be of relevance to women with polycystic ovary syndrome, whose reproductive and metabolic phenotype is captured by the gestational testosterone-treated offspring.

  10. Epithelial membrane protein 2 (EMP2) deficiency alters placental angiogenesis, mimicking features of human placental insufficiency.

    PubMed

    Williams, Carmen J; Chu, Alison; Jefferson, Wendy N; Casero, David; Sudhakar, Deepthi; Khurana, Nevil; Hogue, Claire P; Aryasomayajula, Chinmayi; Patel, Priya; Sullivan, Peggy; Padilla-Banks, Elizabeth; Mohandessi, Shabnam; Janzen, Carla; Wadehra, Madhuri

    2017-03-14

    Epithelial membrane protein-2 (EMP2) is a tetraspan protein predicted to regulate placental development. Highly expressed in secretory endometrium and trophectoderm cells, previous studies suggest that it may regulate implantation by orchestrating the surface expression of integrins and other membrane proteins. In order to test the role of EMP2 in pregnancy, mice lacking EMP2 (Emp2(-/-) ) were generated. Emp2(-/-) females are fertile but have reduced litter sizes when carrying Emp2(-/-) but not Emp2(+/-) fetuses. Placentas of Emp2(-/-) fetuses exhibit dysregulation in pathways related to neoangiogenesis, coagulation, and oxidative stress, and have increased fibrin deposition and altered vasculature. Given that these findings often occur due to placental insufficiency resulting in an oxygen-poor environment, the expression of hypoxia-inducible factor-1 alpha (HIF-1α) was examined. Placentas from Emp2(-/-) fetuses had increased total HIF-1α expression in large part through an increase in uterine NK (uNK) cells, demonstrating a unique interplay between uNK cells and trophoblasts modulated through EMP2. To determine if these results translated to human pregnancy, placentas from normal, term deliveries or those complicated by placental insufficiency resulting in intrauterine growth restriction (IUGR) were stained for EMP2. EMP2 was significantly reduced in both villous and extravillous trophoblast populations in IUGR placentas. Experiments in vitro using human trophoblast cells lines indicate that EMP2 modulates angiogenesis by altering HIF-1α expression. Our results reveal a novel role for EMP2 in regulating trophoblast function and vascular development in mice and humans and suggest it may be a new biomarker for placental insufficiency.

  11. Placental copper transport in the brindled mouse

    SciTech Connect

    Garnica, A.; Bates, J.

    1986-03-01

    Pregnant brindled (brin) mice were injected at 16 or 19 days gestation with 2 doses of CuCl/sub 2/ 6 mcg/g/dose, separated by 12 h, and sacrificed 6 h after the second. The copper conc. in placenta (P) and kidneys (K) of uninjected (UI) brin mice were higher than in UI controls, while conc. in liver (L) and fetal carcass (F) were lower. After injection (I), placental copper conc. increased while the carcass conc. remained unchanged. Brin mouse is a model for the human inborn error of copper metabolism, Menkes syndrome, which is characterized by signs of copper deficiency. These data indicate that metabolism of copper in brin fetus is abnormal, but depressed fetal copper levels cannot be corrected by acute copper dosing because of the sequestration of copper in placenta.

  12. Why is placentation abnormal in preeclampsia?

    PubMed Central

    Fisher, Susan J.

    2015-01-01

    The causes of preeclampsia remain one of the great medical mysteries of our time. This syndrome is thought to occur in two stages with abnormal placentation leading to a maternal inflammatory response. Specific regions of the placenta have distinct pathological features. During normal pregnancy, cytotrophoblasts emigrate from the chorionic villi and invade the uterus, reaching the inner third of the myometrium. This unusual process is made even more exceptional by the fact that the placental cells are hemi-allogeneic, co-expressing maternal and paternal genomes. Within the uterine wall, cytotrophoblasts deeply invade the spiral arteries. Cytotrophoblasts migrate up these vessels and replace, in a retrograde fashion, the maternal endothelial lining. They also insert themselves amongst the smooth muscle cells that form the tunica media. As a result, the spiral arteries attain the physiological properties that are required to adequately perfuse the placenta. In comparison, invasion of the venous side of the uterine circulation is minimal, sufficient to enable venous return. In preeclampsia, cytotrophoblast invasion of the interstitial uterine compartment is frequently shallow, although not consistently so. In many locations, spiral artery invasion is incomplete. There are many fewer endovascular cytotrophoblasts and some vessels retain portions of their endothelial lining with relatively intact muscular coats while others are not modified. Work from our group showed that these defects mirror deficits in the differentiation program that enables cytotrophoblast invasion of the uterine wall. During normal pregnancy, invasion is accompanied by downregulation of epithelial-like molecules that are indicative of their ectodermal origin and upregulation of numerous receptors and ligands that are typically expressed by endothelial or vascular smooth muscle cells. For example, the expression of epithelial-cadherin, the cell-cell adhesion molecule that many ectodermal

  13. Placental C4d deposition is a feature of defective placentation: observations in cases of preeclampsia and miscarriage.

    PubMed

    Kim, Eun Na; Yoon, Bo Hyun; Lee, Joong Yeup; Hwang, Doyeong; Kim, Ki Chul; Lee, JoonHo; Shim, Jae-Yoon; Kim, Chong Jai

    2015-06-01

    Placental C4d deposition is frequent in preeclampsia, and shallow placentation is a characteristic of both preeclampsia and miscarriage. This study was conducted to determine the relationship among placental C4d, maternal human leukocyte antigen (HLA) antibodies, and placental pathology in preeclampsia and miscarriage cases. The patient population (N = 104) included those with (1) preterm preeclampsia with fetal growth restriction (PE-FGR; n = 21), (2) preterm preeclampsia (PE; n = 20), (3) spontaneous preterm delivery (sPTD; n = 39), and (4) miscarriage (n = 24). C4d immunohistochemistry was performed, and the presence of maternal plasma HLA antibodies was examined. C4d staining of the syncytiotrophoblast was more frequent in PE-FGR patients (76.2 %) than in PE (10.0 %; p < 0.001) and sPTD (2.6 %; p < 0.001) patients. Maternal HLA antibody-positive rate was not different among the study groups. There was a significant correlation between C4d immunoreactivity and placental pathology consistent with maternal vascular underperfusion (p < 0.001) but not with maternal HLA antibody status. In miscarriages, the positive rates of C4d, HLA class I, and HLA class II antibodies were 58.3, 25.0, and 12.5 %, respectively. There was no correlation between the presence of maternal HLA class I or II antibodies and placental C4d immunoreactivity. This study confirms frequent placental C4d deposition in preeclampsia with fetal growth restriction and miscarriage. The association between placental C4d deposition and pathological findings of maternal vascular underperfusion suggests that C4d staining of the syncytiotrophoblast is a consequence of defective placentation rather than of a specific maternal immune response against fetal HLA. The study also demonstrates the usefulness of C4d as a biomarker of placentas at risk.

  14. Aromatase expression in the brain of the ruffed grouse (Bonasa umbellus) and comparisons with other galliform birds (Aves, Galliformes).

    PubMed

    Corfield, Jeremy R; Harada, Nobuhiro; Iwaniuk, Andrew N

    2013-01-01

    The enzyme aromatase is important for regulating sexual and aggressive behaviors during the reproductive season, including many aspects of courtship. In birds, aromatase is expressed at high levels in a number of different brain regions. Although this expression does vary among species, the extent to which the distribution of aromatase positive cells reflects species differences in courtship and other behaviors is not well established. Here, we examine the distribution of aromatase immunoreactive (ARO) neurons in the brain of a species with a unique courtship display, the ruffed grouse (Bonasa umbellus). Unlike most other galliforms, male ruffed grouse do not vocalize as part of their courtship and instead use their wings to create a non-vocal auditory signal to attract females. Because aromatase is involved in courtship behaviors in several bird species, including other galliforms, we hypothesized that aromatase distribution in the ruffed grouse would differ from that of other galliforms. We used an antibody raised against quail aromatase to examine aromatase immunoreactivity in the ruffed grouse, the closely related spruce grouse (Falcipennis canadensis) and the Japanese quail (Coturnix japonica). In all three species, ARO neurons were identified in the medial preoptic nucleus, the bed nucleus of the stria terminalis and the nucleus ventromedialis hypothalami. Both grouse species had ARO neurons in two regions of the telencephalon, the hyperpallium, and entopallium, and the ruffed grouse also in field L. ARO neurons were only found in one region in the telencephalon of the Japanese quail, the septum. In general, breeding male ruffed grouse had significantly more ARO neurons and those neurons were larger than that of both the non-breeding male and female ruffed grouse. Aromatase expression in the telencephalon of the ruffed grouse suggests that steroid hormones might modulate responses to visual and acoustic stimuli, but how this relates to species differences in

  15. Direct Effects, Compensation, and Recovery in Female Fathead Minnows Exposed to the Aromatase Inhibitor Fadrozole

    EPA Science Inventory

    A variety of chemicals present in the environment have the potential to inhibit aromatase, an enzyme critical to estrogen synthesis. The objective of this study was to provide a detailed characterization of the molecular and biochemical responses of female fathead minnows to a m...

  16. Direct Effects, Compensation, and Recovery in Female Fathead Minnows Exposed to a Model Aromatase Inhibitor

    EPA Science Inventory

    The paper reports on the effects of a model aromatase inhibitor, fadrozole, on molecular and biochemical endpoints within the fathead minnow reproductive axis. Unlike previous studies, this work incorporated extensive time-course characterization over the course of an 8 d exposu...

  17. Sex Amphibian, Xenopus tropicalis, following Larval Exposure to an Aromatase Inhibitor

    EPA Science Inventory

    Aromatase is a steroidogenic enzyme that catalyzes the conversion of androgens to estrogens in vertebrates. Modulation of this enzyme’s activity by xenobiotic exposure has been shown to adversely affect gonadal differentiation in a number of diverse species. We hypothesized tha...

  18. Nonsteroidal aromatase inhibitors for the treatment of breast cancer: an update.

    PubMed

    Gobbi, Silvia; Rampa, Angela; Belluti, Federica; Bisi, Alessandra

    2014-01-01

    Estrogens are known to be important in breast cancer growth in both pre- and post-menopausal women. Although circulating estrogen concentrations are very low after menopause, peripheral tissues generate sufficient concentrations to stimulate tumor growth. As aromatase is the rate-limiting enzyme in estrogen biosynthesis, inhibitors of this enzyme represent effective targeted therapy for breast cancer. Three compounds are now FDA approved and have become the first-choice endocrine drugs for postmenopausal breast cancer patients, since they are associated with superior activity and better general tolerability when compared with the estrogen receptor modulator tamoxifen. Nevertheless, some questions concerning the use of aromatase inhibitors for the treatment of breast cancer still need to be addressed, mainly related to their side-effects and the development of resistance, making research in this field still appealing. Many research groups, including our own, are still dealing with the search of new compounds that possess aromatase inhibitory properties. In this review an update of the latest achievements in the field of nonsteroidal aromatase inhibitors will be given.

  19. Hypogonadism Associated with Cyp19a1 (Aromatase) Posttranscriptional Upregulation in Celf1 Knockout Mice.

    PubMed

    Boulanger, Gaella; Cibois, Marie; Viet, Justine; Fostier, Alexis; Deschamps, Stéphane; Pastezeur, Sylvain; Massart, Catherine; Gschloessl, Bernhard; Gautier-Courteille, Carole; Paillard, Luc

    2015-09-01

    CELF1 is a multifunctional RNA-binding protein that controls several aspects of RNA fate. The targeted disruption of the Celf1 gene in mice causes male infertility due to impaired spermiogenesis, the postmeiotic differentiation of male gametes. Here, we investigated the molecular reasons that underlie this testicular phenotype. By measuring sex hormone levels, we detected low concentrations of testosterone in Celf1-null mice. We investigated the effect of Celf1 disruption on the expression levels of steroidogenic enzyme genes, and we observed that Cyp19a1 was upregulated. Cyp19a1 encodes aromatase, which transforms testosterone into estradiol. Administration of testosterone or the aromatase inhibitor letrozole partly rescued the spermiogenesis defects, indicating that a lack of testosterone associated with excessive aromatase contributes to the testicular phenotype. In vivo and in vitro interaction assays demonstrated that CELF1 binds to Cyp19a1 mRNA, and reporter assays supported the conclusion that CELF1 directly represses Cyp19a1 translation. We conclude that CELF1 downregulates Cyp19a1 (Aromatase) posttranscriptionally to achieve high concentrations of testosterone compatible with spermiogenesis completion. We discuss the implications of these findings with respect to reproductive defects in men, including patients suffering from isolated hypogonadotropic hypogonadism and myotonic dystrophy type I.

  20. Hypothesis testing with computational modeling: linking aromatase inhibition with plasma vitellogenin dynamics in fathead minnows

    EPA Science Inventory

    Fadrozole inhibits aromatase (CYP19A), a key enzyme that converts testosterone to estradiol (E2). In fish, E2 concentrations control hepatic synthesis ofthe glycolipoprotein vitellogenin (VTG), an egg yolk precursor protein essential to oocyte development and larval survival. Whe...

  1. A Study to Evaluate Genetic Predictors of Aromatase Inhibitor Musculoskeletal Symptoms (AIMSS) | Division of Cancer Prevention

    Cancer.gov

    E1Z11 is a study to determine whether certain genetic information can predict which breast cancer patients will discontinue treatment with AIs due to the development of musculoskeletal symptoms (MSS). Women with stage 1-111 breast cancer who are prescribed the aromatase inhibitor anastrozole as treatment may join. |

  2. Molecular phylogenetics and the origins of placental mammals.

    PubMed

    Murphy, W J; Eizirik, E; Johnson, W E; Zhang, Y P; Ryder, O A; O'Brien, S J

    2001-02-01

    The precise hierarchy of ancient divergence events that led to the present assemblage of modern placental mammals has been an area of controversy among morphologists, palaeontologists and molecular evolutionists. Here we address the potential weaknesses of limited character and taxon sampling in a comprehensive molecular phylogenetic analysis of 64 species sampled across all extant orders of placental mammals. We examined sequence variation in 18 homologous gene segments (including nearly 10,000 base pairs) that were selected for maximal phylogenetic informativeness in resolving the hierarchy of early mammalian divergence. Phylogenetic analyses identify four primary superordinal clades: (I) Afrotheria (elephants, manatees, hyraxes, tenrecs, aardvark and elephant shrews); (II) Xenarthra (sloths, anteaters and armadillos); (III) Glires (rodents and lagomorphs), as a sister taxon to primates, flying lemurs and tree shrews; and (IV) the remaining orders of placental mammals (cetaceans, artiodactyls, perissodactyls, carnivores, pangolins, bats and core insectivores). Our results provide new insight into the pattern of the early placental mammal radiation.

  3. The new framework for understanding placental mammal evolution.

    PubMed

    Asher, Robert J; Bennett, Nigel; Lehmann, Thomas

    2009-08-01

    An unprecedented level of confidence has recently crystallized around a new hypothesis of how living placental mammals share a pattern of common descent. The major groups are afrotheres (e.g., aardvarks, elephants), xenarthrans (e.g., anteaters, sloths), laurasiatheres (e.g., horses, shrews), and euarchontoglires (e.g., humans, rodents). Compared with previous hypotheses this tree is remarkably stable; however, some uncertainty persists about the location of the placental root, and (for example) the position of bats within laurasiatheres, of sea cows and aardvarks within afrotheres, and of dermopterans within euarchontoglires. A variety of names for sub-clades within the new placental mammal tree have been proposed, not all of which follow conventions regarding priority and stability. More importantly, the new phylogenetic framework enables the formulation of new hypotheses and testing thereof, for example regarding the possible developmental dichotomy that seems to distinguish members of the newly identified southern and northern radiations of living placental mammals.

  4. Placental Abruption Revealed by Hemoperitoneum: A Case Report

    PubMed Central

    Bertholdt, C.; Vincent-Rohfritsch, A.; Tsatsaris, V.; Goffinet, F.

    2016-01-01

    Background Hemoperitoneum is a life-threatening surgical emergency. Diagnosis of the cause is often difficult, in particular, during pregnancy when it may be either obstetric or nonobstetric. Case We report the case of a hemoperitoneum caused by the backflow of blood through a uterine tube, due to placental abruption. Conclusion Hemoperitoneum in pregnant women with no other signs can reveal placental abruption. The difficulty in identifying the cause may delay appropriate management. PMID:27994944

  5. [Fetal circulation in normal pregnancy and in placental insufficiency].

    PubMed

    Ivanov, B; Malinova, M

    2010-01-01

    The fetal circulation is different from the adult circulation. One of the quite common conditions that are challenging to the developing fetus is placental hypoxia. Regardless of its cause, placental vascular insufficiency is commonly assumed to be an important factor in the development of intrauterine growth retardation. Several mechanisms are involved in the fetal adaptation to the decompensation during hypoxemia. Doppler Ultrasound technologies can help to evaluate of the fetal wellbeing.

  6. Placental steroid deficiency: association with arylsulfatase A deficiency.

    PubMed Central

    Vidgoff, J; Buxman, M M; Shapiro, L J; Dimond, R L; Wilson, T G; Hepburn, C A; Tabei, T; Heinrichs, W R

    1982-01-01

    A family with an obstetric history consistent with placental sulfatase deficiency has X-linked ichthyosis. Steroid sulfatase deficiency was confirmed in placenta, leukocytes, and cultured skin fibroblasts of affected males; arylsulfatase A diminution was also observed in these tissues of both affected males and 2 generations of related females. No symptoms of metachromatic leukodystrophy are present in any family members. In this family, placental sulfatase deficiency, and arylsulfatase A pseudodeficiency are nonallelic. PMID:6123259

  7. Cytochrome aa3 in Haloferax volcanii

    PubMed Central

    Tanaka, Mikiei; Ogawa, Naohide; Ihara, Kunio; Sugiyama, Yasuo; Mukohata, Yasuo

    2002-01-01

    A cytochrome in an extremely halophilic archaeon, Haloferax volcanii, was purified to homogeneity. This protein displayed a redox difference spectrum that is characteristic of a-type cytochromes and a CN− complex spectrum that indicates the presence of heme a and heme a3. This cytochrome aa3 consisted of 44- and 35-kDa subunits. The amino acid sequence of the 44-kDa subunit was similar to that of the heme-copper oxidase subunit I, and critical amino acid residues for metal binding, such as histidines, were highly conserved. The reduced cytochrome c partially purified from the bacterial membrane fraction was oxidized by the cytochrome aa3, providing physiological evidence for electron transfer from cytochrome c to cytochrome aa3 in archaea. PMID:11790755

  8. Placental mammal diversification and the Cretaceous-Tertiary boundary.

    PubMed

    Springer, Mark S; Murphy, William J; Eizirik, Eduardo; O'Brien, Stephen J

    2003-02-04

    Competing hypotheses for the timing of the placental mammal radiation focus on whether extant placental orders originated and diversified before or after the Cretaceous-Tertiary (KT) boundary. Molecular studies that have addressed this issue suffer from single calibration points, unwarranted assumptions about the molecular clock, andor taxon sampling that lacks representatives of all placental orders. We investigated this problem using the largest available molecular data set for placental mammals, which includes segments of 19 nuclear and three mitochondrial genes for representatives of all extant placental orders. We used the ThorneKishino method, which permits simultaneous constraints from the fossil record and allows rates of molecular evolution to vary on different branches of a phylogenetic tree. Analyses that used different sets of fossil constraints, different priors for the base of Placentalia, and different data partitions all support interordinal divergences in the Cretaceous followed by intraordinal diversification mostly after the KT boundary. Four placental orders show intraordinal diversification that predates the KT boundary, but only by an average of 10 million years. In contrast to some molecular studies that date the rat-mouse split as old as 46 million years, our results show improved agreement with the fossil record and place this split at 16-23 million years. To test the hypothesis that molecular estimates of Cretaceous divergence times are an artifact of increased body size subsequent to the KT boundary, we also performed analyses with a "KT body size" taxon set. In these analyses, interordinal splits remained in the Cretaceous.

  9. Patterns of ossification in southern versus northern placental mammals.

    PubMed

    Hautier, Lionel; Bennett, Nigel C; Viljoen, Hermien; Howard, Lauren; Milinkovitch, Michel C; Tzika, Athanasia C; Goswami, Anjali; Asher, Robert J

    2013-07-01

    Consensus on placental mammal phylogeny is fairly recent compared to that for vertebrates as a whole. A stable phylogenetic hypothesis enables investigation into the possibility that placental clades differ from one another in terms of their development. Here, we focus on the sequence of skeletal ossification as a possible source of developmental distinctiveness in "northern" (Laurasiatheria and Euarchontoglires) versus "southern" (Afrotheria and Xenarthra) placental clades. We contribute data on cranial and postcranial ossification events during growth in Afrotheria, including elephants, hyraxes, golden moles, tenrecs, sengis, and aardvarks. We use three different techniques to quantify sequence heterochrony: continuous method, sequence-ANOVA (analysis of variance) and event-paring/Parsimov. We show that afrotherians significantly differ from other placentals by an early ossification of the orbitosphenoid and caudal vertebrae. Our analysis also suggests that both southern placental groups show a greater degree of developmental variability; however, they rarely seem to vary in the same direction, especially regarding the shifts that differ statistically. The latter observation is inconsistent with the Atlantogenata hypothesis in which afrotherians are considered as the sister clade of xenarthrans. Interestingly, ancestral nodes for Laurasiatheria and Euarchontoglires show very similar trends and our results suggest that developmental homogeneity in some ossification sequences may be restricted to northern placental mammals (Boreoeutheria).

  10. Maternal micronutrients, omega-3 fatty acids, and placental PPARγ expression.

    PubMed

    Meher, Akshaya P; Joshi, Asmita A; Joshi, Sadhana R

    2014-07-01

    An altered one-carbon cycle is known to influence placental and fetal development. We hypothesize that deficiency of maternal micronutrients such as folic acid and vitamin B12 will lead to increased oxidative stress, reduced long-chain polyunsaturated fatty acids, and altered expression of peroxisome proliferator activated receptor (PPARγ) in the placenta, and omega-3 fatty acid supplementation to these diets will increase the expression of PPARγ. Female rats were divided into 5 groups: control, folic acid deficient, vitamin B12 deficient, folic acid deficient + omega-3 fatty acid supplemented, and vitamin B12 deficient + omega-3 fatty acid supplemented. Dams were dissected on gestational day 20. Maternal micronutrient deficiency leads to lower (p < 0.05) levels of placental docosahexaenoic acid, arachidonic acid, PPARγ expression and higher (p < 0.05) levels of plasma malonidialdehyde, placental IL-6, and TNF-α. Omega-3 fatty acid supplementation to a vitamin B12 deficient diet normalized the expression of PPARγ and lowered the levels of placental TNF-α. In the case of supplementation to a folic acid deficient diet it lowered the levels of malonidialdehyde and placental IL-6 and TNF-α. This study has implications for fetal growth as oxidative stress, inflammation, and PPARγ are known to play a key role in the placental development.

  11. Relationship between placental traits and maternal intrinsic factors in sheep.

    PubMed

    Ocak, S; Ogun, S; Onder, H

    2013-06-01

    The relationship between maternal intrinsic factors and placental traits was investigated on three Southern Mediterranean breed of sheep; Cukurova Assaf (CA), Cukurova (C) and Cukurova Meat Sheep (CMS). The effect of parity and birth type were also considered in the study as a potential influencing factor. Our hypothesis was to show that while differences in placental traits between breed, parity and birth type affected lamb condition and survivability, its correlation to maternal intrinsic behavioral factors may also be a strong indicator. The study found breed related differences of maternal behavioral factors and also showed significant correlation of these behavioral patterns to various placental traits. It confirmed earlier findings that parity played a major role in the refinement of these behavioral patterns. Significant differences in birth weight (P<0.05), placental weight (P<0.05), number of cotyledons (P<0.01) and cotyledon length (P<0.05) was seen between breeds. Cotyledon weight (P<0.05), width (P<0.01) and length (P<0.05) were found to differ by parity. Breed and parity interaction significantly influenced cotyledon quantity. While we detected breed specific differences in relation to maternal intrinsic factors we also noticed significant variance within breeds to these behavioral patterns when linked to placental traits. Further study is required on the correlation between placental traits and postnatal behavior on not just the ewes but also on their lambs. This could have a significant bearing on how producers manage and maximize lamb survivability.

  12. Association between PAPP-A and placental thickness

    PubMed Central

    Mesdaghi-nia, Elaheh; Behrashi, Mitra; Saeidi, Arezoo; Abedzadeh Kalahroodi, Masoomeh; Sehat, Mojtaba

    2016-01-01

    Background: Measuring of maternal serum pregnancy-associated plasma protein-A (PAPP-A) in first trimester can be a way for early detection of adverse prenatal outcome due to faulty placenta. Objective: The aim was to Determination of association between placental thickness in second trimester with low level of PAPP-A in first trimester. Materials and Methods: In this cohort study, serum PAPP-A of 187 pregnant women was measured in the first trimester of pregnancy. Patients who had PAPP-A ≤0.8 MOM were in exposed and others who had PAPP-A >0.8 defined as unexposed group. The criteria of placental thickness in ultrasound study was thickness of 4 cm or more than 50% of placental length. Results: Of 187 patients, 87 patients had PAPP-A >0.8 and 93 patients had PAPP-A ≤0.8. Women with low levels of PAPP-A in the first trimester, had an increased incidence placental thickness of 34.4%, whereas another group had about 15% (p=0.002). Also, PAPP-A levels had acceptable sensitivity and specificity for placental thickness detection (71.1% and 54.8%, respectively. Conclusion: Our study showed that serum level of PAPP-A generally was low (≤0.8) in women with a thick placenta (>4 cm or >50% of placental length). The first trimester of pregnancy measurement of PAPP-A will be more predictable for healthy placenta. PMID:27525326

  13. Placental angiogenesis in sheep models of compromised pregnancy

    PubMed Central

    Reynolds, Lawrence P; Borowicz, Pawel P; Vonnahme, Kimberly A; Johnson, Mary Lynn; Grazul-Bilska, Anna T; Redmer, Dale A; Caton, Joel S

    2005-01-01

    Because the placenta is the organ that transports nutrients, respiratory gases and wastes between the maternal and fetal systems, development of its vascular beds is essential to normal placental function, and thus in supporting normal fetal growth. Compromised fetal growth and development have adverse health consequences during the neonatal period and throughout adult life. To establish the role of placental angiogenesis in compromised pregnancies, we first evaluated the pattern of placental angiogenesis and expression of angiogenic factors throughout normal pregnancy. In addition, we and others have established a variety of sheep models to evaluate the effects on fetal growth of various factors including maternal nutrient excess or deprivation and specific nutrients, maternal age, maternal and fetal genotype, increased numbers of fetuses, environmental thermal stress, and high altitude (hypobaric) conditions. Although placental angiogenesis is altered in each of these models in which fetal growth is adversely affected, the specific effect on placental angiogenesis depends on the type of ‘stress’ to which the pregnancy is subjected, and also differs between the fetal and maternal systems and between genotypes. We believe that the models of compromised pregnancy and the methods described in this review will enable us to develop a much better understanding of the mechanisms responsible for alterations in placental vascular development. PMID:15760944

  14. Probing the origins of aromatase inhibitory activity of disubstituted coumarins via QSAR and molecular docking.

    PubMed

    Worachartcheewan, Apilak; Suvannang, Naravut; Prachayasittikul, Supaluk; Prachayasittikul, Virapong; Nantasenamat, Chanin

    2014-01-01

    This study investigated the quantitative structure-activity relationship (QSAR) of imidazole derivatives of 4,7-disubstituted coumarins as inhibitors of aromatase, a potential therapeutic protein target for the treatment of breast cancer. Herein, a series of 3,7- and 4,7-disubstituted coumarin derivatives (1-34) with R1 and R2 substituents bearing aromatase inhibitory activity were modeled as a function of molecular and quantum chemical descriptors derived from low-energy conformer geometrically optimized at B3LYP/6-31G(d) level of theory. Insights on origins of aromatase inhibitory activity was afforded by the computed set of 7 descriptors comprising of F10[N-O], Inflammat-50, Psychotic-80, H-047, BELe1, B10[C-O] and MAXDP. Such significant descriptors were used for QSAR model construction and results indicated that model 4 afforded the best statistical performance. Good predictive performance were achieved as verified from the internal (comprising the training and the leave-one-out cross-validation (LOO-CV) sets) and external sets affording the following statistical parameters: R (2) Tr = 0.9576 and RMSETr = 0.0958 for the training set; Q (2) CV = 0.9239 and RMSECV = 0.1304 for the LOO-CV set as well as Q (2) Ext = 0.7268 and RMSEExt = 0.2927 for the external set. Significant descriptors showed correlation with functional substituents, particularly, R1 in governing high potency as aromatase inhibitor. Molecular docking calculations suggest that key residues interacting with the coumarins were predominantly lipophilic or non-polar while a few were polar and positively-charged. Findings illuminated herein serve as the impetus that can be used to rationally guide the design of new aromatase inhibitors.

  15. Aromatase inhibitors: mechanism of action and role in the treatment of breast cancer.

    PubMed

    Miller, William R

    2003-08-01

    The natural history of breast cancer is closely linked with estrogens. These hormones influence both risk to the disease and growth of many established tumors. Consequently, measures that either inhibit the synthesis or block the mechanism of action of estrogens are attractive strategies for therapeutic intervention. This is particularly true in postmenopausal women in whom hormone responsiveness is common and estrogen synthesis is primarily sited peripherally in adipose tissue, muscle and breast tissue, rather than in the ovaries as in premenopausal women. In terms of inhibiting production, the most specific effects are best achieved by blocking the last step in biosynthesis, the conversion of androgens to estrogens by the heme-containing enzyme, aromatase. Two major classes of aromatase inhibitors have been developed and are currently in clinical use. Type I steroidal drugs include formestane and exemestane; they are androgen substrate analogues that bind competitively but irreversibly to the enzyme and have been marketed as "inactivators." Type II nonsteroidal inhibitors such as anastrozole and letrozole are triazoles; they bind reversibly to the enzyme and fit into the substrate binding site, such that azole nitrogens interact with the heme prosthetic group. This type of association provides exquisite potency for and specificity against the aromatase enzyme. These agents represent several generations of development, with each step in the evolution producing an increase in both potency and specificity. The latest aromatase inhibitors are drugs of immense potential that will undoubtedly play a major role in the management of postmenopausal women with hormone-dependent breast cancer. They also represent tools by which to elucidate the roles of both aromatase and estrogen in the development and growth of breast cancer.

  16. Seasonal Changes of Androgen Receptor, Estrogen Receptors and Aromatase Expression in the Medial Preoptic Area of the Wild Male Ground Squirrels (Citellus Dauricus Brandt)

    PubMed Central

    Zhang, F.; Wang, J.; Jiao, Y.; Zhang, L.; Zhang, H.; Sheng, X.; Han, Y.; Yuan, Z.; Weng, Q.

    2016-01-01

    The wild ground squirrel is a typical seasonal breeder. In this study, using RT-PCR, western blot and immunohistochemistry, we investigated the mRNA and protein expressions of androgen receptor (AR), estrogen receptors a and β (ERα and ERβ) and aromatase cytochrome P450 (P450arom) in the medial preoptic area (MPOA) of hypothalamus of the wild male ground squirrel during the breeding season (April), the non-breeding season (June) and pre-hibernation (September). AR, ERα, ERβ and P450arom protein/mRNA were present in the MPOA of all seasons detected. The immunostaining of AR and ERα showed no significant changes in different periods, whereas ERβ and P450arom had higher immunoreactivities during the breeding season and pre-hibernation when compared to those of the non-breeding season. Consistently, both the protein and mRNA levels of P450arom and ERβ were higher in the MPOA of pre-hibernation and the breeding season than in the non-breeding season, whereas no significant difference amongst the three periods was observed for AR and ERα levels. These findings suggested that the MPOA of hypothalamus may be a direct target of androgen and estrogen. Androgen may play important regulatory roles through its receptor and/or the aromatized estrogen in the MPOA of hypothalamus of the wild male ground squirrels. PMID:27349316

  17. Models for placental transfer studies of drugs.

    PubMed

    Bourget, P; Roulot, C; Fernandez, H

    1995-02-01

    Pregnancy is a specific dynamic state, and the potential usefulness of caring for a disorder in the fetus or the mother is now well established. Previously, pregnant women have been excluded from clinical trials, therefore only a few studies concerning evaluation of the pregestational metabolism or transplacental transfer (TPT) of drugs exist. Questions regarding the TPT of drugs are extensive and complex. For example, does TPT occur at a given gestational age, in the context of a particular type of pathology or when a drug is administered by a certain dosage regimen? If this is the case, what is the rapidity of penetration of the products of conception by the drug (bearing in mind its physicochemical characteristics)? Need harmful adverse effects on the child be feared? Is such penetration desirable, of no consequence, or dangerous? Does the possibility exist of accumulation in the placenta, fetal tissue or amniotic fluid? Should such findings modify the therapeutic regimens of drugs given to expectant mothers? Exchange mechanisms are complicated and models developed in vitro only partially reflect the actual equilibria that exist between mother and fetus. These include: (i) the perfused cotyledon model, which while simple, elegant and inexpensive, offers only a localised, restricted and fixed view of pregnancy; (ii) isolated anatomical fractions that are informative, but which straddle the border between physiology and pharmacology; and (iii) the necessary study, using microsomes, of placental metabolic capacity (enzyme cartography). In vivo study of TPT is based upon various multicompartmental pharmacokinetic models, some of which have been relatively validated in animals. The simplest indicator for the in vivo evaluation of TPT of a drug in the human species is determination of a feto-maternal blood concentration ratio (usually performed at the time of placental separation). However, the usefulness and limitations of this parameter are controversial, and it

  18. Cytochromes P450 in Nanodiscs

    PubMed Central

    Denisov, Ilia G.; Sligar, Stephen G.

    2010-01-01

    Nanodiscs have proven to be a versatile tool for the study all types of membrane proteins, including receptors, transporters, enzymes and viral antigens. The self-assembled Nanodisc system provides a robust and common means for rendering these targets soluble in aqueous media while providing a native like bilayer environment that maintains functional activity. This system has thus provided a means for studying the extensive collection of membrane bound cytochromes P450 with the same biochemical and biophysical tools that have been previously limited to use with the soluble P450s. These include a plethora of spectroscopic, kinetic and surface based methods. Significant improvements in homogeneity and stability of these preparations open new possibilities for detailed analysis of equilibrium and steady-state kinetic characteristics of catalytic mechanisms of human cytochromes P450 involved in xenobiotic metabolism and in steroid biosynthesis. The experimental methods developed for physico-chemical and functional studies of membrane cytochromes P450 incorporated in Nanodiscs allow for more detailed understanding of the scientific questions along the lines pioneered by Professor Klaus Ruckpaul and his array of colleagues and collaborators. PMID:20685623

  19. Effects of Pharmaceuticals Used for Breast Cancer Treatment on Reproduction and Aromatase Activity in a Marine Fish

    EPA Science Inventory

    Laboratory experiments were conducted with the marine fish cunner (Tautogolabrus adspersus) to evaluate whether four pharmaceuticals used in breast cancer treatment have an impact on reproduction or aromatase activity. Tamoxifen binds to estrogen receptors, while anastrozole, let...

  20. EFFECTS OF INCUBATION TEMPERATURE AND ESTROGEN EXPOSURE ON AROMATASE ACTIVITY IN THE BRAIN AND GONADS OF EMBRYONIC ALLIGATORS

    EPA Science Inventory

    During embryogenesis, incubation temperature and the hormonal environment influence gonadal differentiation of some reptiles, including all crocodilians. Current evidence suggests that aromatase, the enzyme that converts androgens to estrogens, has a role in sexual differentiatio...

  1. ALTERATIONS IN THE TRANSCRIPTOME AND PROTEOME OF ZEBRAFISH (DANIO RERIO) EXPOSED TO FADROZOLE, A MODEL AROMATASE INHIBITOR

    EPA Science Inventory

    Fadrozole is a reversible, competitive inhibitor of aromatase activity and therefore an endocrine-disrupting compound (EDC) that disrupts steroidogenesis by inhibiting the conversion of testosterone to 172-estradiol. While fadrozole is a therapeutic drug with generally no enviro...

  2. Erasmus Darwin's enlightened views on placental function.

    PubMed

    Pijnenborg, R; Vercruysse, L

    2007-01-01

    In his major work "Zoonomia", Erasmus Darwin (1731-1802) devoted one chapter to the placenta, in which the new knowledge of the recently discovered element oxygen was applied to the functioning of this organ. He considered the "cavities" or "lacunae" in the placenta as the main areas for oxygenation of the fetal blood, as he thought them to be structurally comparable to the lungs and the gills of fish. He obviously was aware of species differences in the uterine arterial blood supply to the placenta between humans and cows, assuming a higher contractility of the vasculature in the latter species. The new evidence for a primarily respiratory role overshadowed ideas of a possible nutritive function of the placenta. Since Hunter's definitive demonstration of separate maternal and fetal blood circulations, nutritive functions of the placenta needed to be explained by transmembrane transport processes, which were unknown at that time. Instead Erasmus Darwin erroneously considered the amniotic fluid as the main source of nutrients for the fetus. His understanding of placental respiration found expression in his long poem on the history of life on earth.

  3. Optimising sample collection for placental research.

    PubMed

    Burton, G J; Sebire, N J; Myatt, L; Tannetta, D; Wang, Y-L; Sadovsky, Y; Staff, A C; Redman, C W

    2014-01-01

    Biobanks provide an important repository of samples for research purposes. However, for those samples to reflect the in vivo state, and for experimental reliability and reproducibility, careful attention to collection, processing and storage is essential. This is particularly true for the placenta, which is potentially subjected to stressful conditions during delivery, and sample collection may be delayed owing to routine postpartum inspection by clinical staff. In addition, standardisation of the collection procedure enables samples to be shared among research groups, allowing larger datasets to be established. Here, we provide an evidence-based and experts' review of the factors surrounding collection that may influence data obtained from the human placenta. We outline particular requirements for specific techniques, and propose a protocol for optimal sample collection. We recognise that the relevance of these factors, and of the sample types collected to a particular study will depend on the research questions being addressed. We therefore anticipate that researchers will select from the protocol to meet their needs and resources available. Wherever possible, we encourage researchers to extend their collection to include additional samples that can be shared on an international collaborative basis, with appropriate informed consent, to raise the quality, as well as quantity, of placental research.

  4. Evolutionary perspectives into placental biology and disease.

    PubMed

    Chuong, Edward B; Hannibal, Roberta L; Green, Sherril L; Baker, Julie C

    2013-12-01

    In all mammals including humans, development takes place within the protective environment of the maternal womb. Throughout gestation, nutrients and waste products are continuously exchanged between mother and fetus through the placenta. Despite the clear importance of the placenta to successful pregnancy and the health of both mother and offspring, relatively little is understood about the biology of the placenta and its role in pregnancy-related diseases. Given that pre- and peri-natal diseases involving the placenta affect millions of women and their newborns worldwide, there is an urgent need to understand placenta biology and development. Here, we suggest that the placenta is an organ under unique selective pressures that have driven its rapid diversification throughout mammalian evolution. The high divergence of the placenta complicates the use of non-human animal models and necessitates an evolutionary perspective when studying its biology and role in disease. We suggest that diversifying evolution of the placenta is primarily driven by intraspecies evolutionary conflict between mother and fetus, and that many pregnancy diseases are a consequence of this evolutionary force. Understanding how maternal-fetal conflict shapes both basic placental and reproductive biology - in all species - will provide key insights into diseases of pregnancy.

  5. Proteolytic Processing Regulates Placental Growth Factor Activities*

    PubMed Central

    Hoffmann, Daniel C.; Willenborg, Sebastian; Koch, Manuel; Zwolanek, Daniela; Müller, Stefan; Becker, Ann-Kathrin A.; Metzger, Stephanie; Ehrbar, Martin; Kurschat, Peter; Hellmich, Martin; Hubbell, Jeffrey A.; Eming, Sabine A.

    2013-01-01

    Placental growth factor (PlGF) is a critical mediator of blood vessel formation, yet mechanisms of its action and regulation are incompletely understood. Here we demonstrate that proteolytic processing regulates the biological activity of PlGF. Specifically, we show that plasmin processing of PlGF-2 yields a protease-resistant core fragment comprising the vascular endothelial growth factor receptor-1 binding site but lacking the carboxyl-terminal domain encoding the heparin-binding domain and an 8-amino acid peptide encoded by exon 7. We have identified plasmin cleavage sites, generated a truncated PlGF118 isoform mimicking plasmin-processed PlGF, and explored its biological function in comparison with that of PlGF-1 and -2. The angiogenic responses induced by the diverse PlGF forms were distinct. Whereas PlGF-2 increased endothelial cell chemotaxis, vascular sprouting, and granulation tissue formation upon skin injury, these activities were abrogated following plasmin digestion. Investigation of PlGF/Neuropilin-1 binding and function suggests a critical role for heparin-binding domain/Neuropilin-1 interaction and its regulation by plasmin processing. Collectively, here we provide new mechanistic insights into the regulation of PlGF-2/Neuropilin-1-mediated tissue vascularization and growth. PMID:23645683

  6. Benefit/risk for adjuvant breast cancer therapy with tamoxifen or aromatase inhibitor use by age, and race/ethnicity.

    PubMed

    Chlebowski, R T; Haque, R; Hedlin, H; Col, N; Paskett, E; Manson, J E; Kubo, J T; Johnson, K C; Wactawski-Wende, J; Pan, K; Anderson, G

    2015-12-01

    In early adjuvant breast cancer trial reports, aromatase inhibitors more effectively reduced breast recurrence with lower risk of thromboembolic events and endometrial cancer than tamoxifen, while aromatase inhibitors had higher fracture and cardiovascular disease risk. We used data from updated patient-level meta-analyses of adjuvant trials in analyses to summarize the benefits and risks of these agents in various clinical circumstances. Baseline incidence rates for health outcomes by age and race/ethnicity, absent aromatase inhibitor, or tamoxifen use were estimated from the Women's Health Initiative. Aromatase inhibitor and tamoxifen effects on distant recurrence were obtained from a meta-analysis of the Arimidex, Tamoxifen, Alone or in Combination (ATAC) and Breast International Group (Big-1-98) clinical trials. Impact on other health outcomes were obtained from meta-analyses of randomized trials comparing aromatase inhibitor to tamoxifen use and from placebo-controlled chemoprevention trials. All health outcomes were given equal weight when modeling net benefit/risk for aromatase inhibitor compared to tamoxifen use by breast cancer recurrence risk, age (decade), race/ethnicity, hysterectomy (yes/no), and by prior myocardial infarction. Over a 10-year period, the benefit/risk index was more favorable for aromatase inhibitor than for tamoxifen as adjuvant breast cancer therapy in almost all circumstances regardless of patient age, race/ethnicity, breast cancer recurrence risk, or presence or absence of a uterus. Only in older women with prior myocardial infarction and low recurrence risk was an advantage for tamoxifen seen. Using a benefit/risk index for endocrine adjuvant breast cancer therapy in postmenopausal women, benefit was higher for aromatase inhibitor use in almost all circumstances.

  7. Testosterone-derived estradiol production by male endothelium is robust and dependent on p450 aromatase via estrogen receptor alpha.

    PubMed

    Villablanca, Amparo C; Tetali, Sarada; Altman, Robin; Ng, Kenneth F; Rutledge, John C

    2013-12-01

    Vascular endothelium expresses both the estrogen receptors (ERs) α and β, and ERα mediates development of early atherosclerosis in male mice. This process is thought to be testosterone-dependent. We hypothesized that male murine aortic endothelium produces robust levels of estradiol by aromatase conversion of testosterone, and that regulation of this process is mediated by the presence of ERs, primarily ERα. Aortic endothelium was isolated from ERα knockout (ERα -/-) and wild-type (ERα +/+) male mice and treated with testosterone or the 5α reduction product dihydrotestosterone (DHT), with or without the P450 aromatase inhibitor anastrazole, or a non-specific estrogen receptor antagonist. Aromatase gene expression and estradiol production were assayed. Treatment with testosterone, but not DHT, caused increased aromatase expression and estradiol production in ERα +/+ endothelium that was attenuated by disruption of ERα in the ERα -/- group. Anastrazole inhibition of aromatase reduced testosterone-induced aromatase expression and estradiol levels in both ERα -/- and ERα +/+ endothelium. Antagonism of both ERs decreased testosterone-induced aromatase expression in both wild-type and knockout groups. The effects of the receptor antagonist on estradiol production differed between the two groups, however, with a reduction in estradiol release from the ERα +/+ cells and complete abolition of estradiol release from the ERα -/- cells. Thus, estradiol production in vascular endothelium from male mice is robust, depends on the aromatic conversion of testosterone and requires functional ERα to achieve maximal levels of estradiol generation. Local vascular production of aromatase-mediated estradiol in response to circulating testosterone may affect ERα-dependent mechanisms to increase susceptibility to early atheroma formation in male mice. This pathway may have important therapeutic relevance for reducing the risk of atherosclerotic cardiovascular disease in

  8. Zoledronic acid inhibits aromatase activity and phosphorylation: potential mechanism for additive zoledronic acid and letrozole drug interaction.

    PubMed

    Schech, Amanda J; Nemieboka, Brandon E; Brodie, Angela H

    2012-11-01

    Zoledronic acid (ZA), a bisphosphonate originally indicated for use in osteoporosis, has been reported to exert a direct effect on breast cancer cells, although the mechanism of this effect is currently unknown. Data from the ABCSG-12 and ZO-FAST clinical trials suggest that treatment with the combination of ZA and aromatase inhibitors (AI) result in increased disease free survival in breast cancer patients over AI alone. To determine whether the mechanism of this combination involved inhibition of aromatase, AC-1 cells (MCF-7 human breast cancer cells transfected with an aromatase construct) were treated simultaneously with combinations of ZA and AI letrozole. This combination significantly increased inhibition of aromatase activity of AC-1 cells when compared to letrozole alone. Treatment of 1 nM letrozole in combination with 1 μM or 10 μM ZA resulted in an additive drug interaction on inhibition of cell viability, as measured by MTT assay. Treatment with ZA was found to inhibit phosphorylation of aromatase on serine residues. Zoledronic acid was also shown to be more effective in inhibiting cell viability in aromatase transfected AC-1 cells when compared to inhibition of cell viability observed in non-transfected MCF-7. Estradiol was able to partially rescue the effect of 1 μM and 10 μM ZA on cell viability following treatment for 72 h, as shown by a shift to the right in the estradiol dose-response curve. In conclusion, these results indicate that the combination of ZA and letrozole results in an additive inhibition of cell viability. Furthermore, ZA alone can inhibit aromatase activity through inhibition of serine phosphorylation events important for aromatase enzymatic activity and contributes to inhibition of cell viability.

  9. Expression of P450 aromatase and 17beta-hydroxysteroid dehydrogenase type 1 at fetal-maternal interface during tubal pregnancy.

    PubMed

    Li, Yan; Qin, Li; Xiao, Zhi-Jie; Wang, Yan-Ling; Herva, Riitta; Leng, Jin-Hua; Lang, Jing-He; Isomaa, Veli; Piao, Yun-Shang

    2003-12-01

    Steroidogenesis in the placenta has been studied widely, but little is known about steroid metabolism in ectopic pregnancy. Previous studies have indicated that trophoblast invasion and placentation in the uterus and the fallopian tube may be controlled by similar mechanisms. As far as 17beta-estradiol (E(2)) production is concerned, it has been well demonstrated that its biosynthesis in the placenta involves the action of P450 aromatase (P450arom) and 17beta-hydroxysteroid dehydrogenase type 1 (17HSD1). The purpose of this study was to characterize the expression pattern of P450arom and 17HSD1 at the fetal-maternal interface, particularly in various trophoblast cells, in tubal pregnancy. Using in situ hybridization, P450arom mRNA was localized in syncytiotrophoblast (ST) cells, which are mainly responsible for hormone production during pregnancy, whereas no signal was detected in villous cytotrophoblast (VCT), column CT and extravillous CT (EVCT) cells. Immunohistochemical assays revealed that 17HSD1 is present in ST cells, a large portion of EVCT cells and 20% of column CT cells. On the other hand, no expression of 17HSD1 was detected in VCT cells. In addition, 17HSD1 was found in epithelial cells of the fallopian tube. Interestingly, the expression level of 17HSD1 in fallopian tube epithelium during tubal pregnancy was significantly higher than that during normal cycle. Our data provide the first evidence that normal and tubal pregnancies possess identical expression of P450arom and 17HSD1 in ST cells and therefore, similar E(2) production in the placenta. Further, the association of 17HSD1 with EVCT cells indicates that 17HSD1 perhaps play a role in trophoblast invasion. Finally, increased expression of 17HSD1 in epithelial cells of fallopian tube may lead to a local E(2) supply sufficient for the maintenance of tubal pregnancy.

  10. Design, synthesis, and biological evaluation of resveratrol analogues as aromatase and quinone reductase 2 inhibitors for chemoprevention of cancer.

    PubMed

    Sun, Bin; Hoshino, Juma; Jermihov, Katie; Marler, Laura; Pezzuto, John M; Mesecar, Andrew D; Cushman, Mark

    2010-07-15

    A series of new resveratrol analogues were designed and synthesized and their inhibitory activities against aromatase were evaluated. The crystal structure of human aromatase (PDB 3eqm) was used to rationalize the mechanism of action of the aromatase inhibitor 32 (IC50 0.59 microM) through docking, molecular mechanics energy minimization, and computer graphics molecular modeling, and the information was utilized to design several very potent inhibitors, including compounds 82 (IC50 70 nM) and 84 (IC50 36 nM). The aromatase inhibitory activities of these compounds are much more potent than that for the lead compound resveratrol, which has an IC50 of 80 microM. In addition to aromatase inhibitory activity, compounds 32 and 44 also displayed potent QR2 inhibitory activity (IC50 1.7 microM and 0.27 microM, respectively) and the high-resolution X-ray structures of QR2 in complex with these two compounds provide insight into their mechanism of QR2 inhibition. The aromatase and quinone reductase inhibitors resulting from these studies have potential value in the treatment and prevention of cancer.

  11. Design, synthesis, and biological evaluation of resveratrol analogues as aromatase and quinone reductase 2 inhibitors for chemoprevention of cancer

    SciTech Connect

    Sun, Bin; Hoshino, Juma; Jermihov, Katie; Marler, Laura; Pezzuto, John M.; Mesecar, Andrew D.; Cushman, Mark

    2012-07-11

    A series of new resveratrol analogues were designed and synthesized and their inhibitory activities against aromatase were evaluated. The crystal structure of human aromatase (PDB 3eqm) was used to rationalize the mechanism of action of the aromatase inhibitor 32 (IC{sub 50} 0.59 {mu}M) through docking, molecular mechanics energy minimization, and computer graphics molecular modeling, and the information was utilized to design several very potent inhibitors, including compounds 82 (IC{sub 50} 70 nM) and 84 (IC{sub 50} 36 nM). The aromatase inhibitory activities of these compounds are much more potent than that for the lead compound resveratrol, which has an IC{sub 50} of 80 {mu}M. In addition to aromatase inhibitory activity, compounds 32 and 44 also displayed potent QR2 inhibitory activity (IC{sub 50} 1.7 {mu}M and 0.27 {mu}M, respectively) and the high-resolution X-ray structures of QR2 in complex with these two compounds provide insight into their mechanism of QR2 inhibition. The aromatase and quinone reductase inhibitors resulting from these studies have potential value in the treatment and prevention of cancer.

  12. Aromatase imaging with [N-methyl-C-11]vorozole PET in healthy men and women

    SciTech Connect

    Biegon, Anat; Fowler, Joanna S.; Alexoff, David L.; Kim, Sung Won; Logan, Jean; Pareto, Deborah; Schlyer, David; Wang, Gene-Jack

    2015-02-19

    Aromatase, the last and obligatory enzyme catalyzing estrogen biosynthesis from androgenic precursors, can be labeled in vivo with ¹¹C-vorozole. Aromatase inhibitors are widely used in breast cancer and other endocrine conditions. The present study aims to provide baseline information defining aromatase distribution in healthy men and women, against which its perturbation in pathological situations can be studied. Methods: ¹¹C-vorozole (111-296 MBq/subject) was injected I.V in 13 men and 20 women (age range 23 to 67). PET data were acquired over a 90 minute period. Each subject had 4 scans, 2/day separated by 2-6 weeks, including brain and torso or pelvis scans. Young women were scanned at 2 discrete phases of the menstrual cycle (midcycle and late luteal). Men and postmenopausal women were also scanned following pretreatment with a clinical dose of the aromatase inhibitor letrozole (“blocking” studies). Time activity curves were obtained and standard uptake values (SUV) calculated for major organs including brain, heart, lungs, liver, kidneys, spleen, muscle, bone and male and female reproductive organs (penis, testes, uterus, ovaries). Organ and whole body radiation exposures were calculated using Olinda software. Results: Liver uptake was higher than all other organs, but was not blocked by pretreatment with letrozole. Mean SUVs in men were higher than in women, and brain uptake was blocked by letrozole. Male brain SUVs were also higher than all other organs (ranging from 0.48±0.05 in lungs to 1.5±0.13 in kidneys). Mean ovarian SUVs (3.08±0.7) were comparable to brain levels and higher than all other organs. Furthermore, ovarian SUVs In young women around the time of ovulation (midcycle) were significantly higher than those measured in the late luteal phase, while aging and cigarette smoking reduced ¹¹C-vorozole uptake. Conclusions: PET with ¹¹C-vorozole is useful for assessing physiological changes in estrogen synthesis capacity in the human body

  13. Aromatase imaging with [N-methyl-C-11]vorozole PET in healthy men and women

    DOE PAGES

    Biegon, Anat; Fowler, Joanna S.; Alexoff, David L.; ...

    2015-02-19

    Aromatase, the last and obligatory enzyme catalyzing estrogen biosynthesis from androgenic precursors, can be labeled in vivo with ¹¹C-vorozole. Aromatase inhibitors are widely used in breast cancer and other endocrine conditions. The present study aims to provide baseline information defining aromatase distribution in healthy men and women, against which its perturbation in pathological situations can be studied. Methods: ¹¹C-vorozole (111-296 MBq/subject) was injected I.V in 13 men and 20 women (age range 23 to 67). PET data were acquired over a 90 minute period. Each subject had 4 scans, 2/day separated by 2-6 weeks, including brain and torso or pelvismore » scans. Young women were scanned at 2 discrete phases of the menstrual cycle (midcycle and late luteal). Men and postmenopausal women were also scanned following pretreatment with a clinical dose of the aromatase inhibitor letrozole (“blocking” studies). Time activity curves were obtained and standard uptake values (SUV) calculated for major organs including brain, heart, lungs, liver, kidneys, spleen, muscle, bone and male and female reproductive organs (penis, testes, uterus, ovaries). Organ and whole body radiation exposures were calculated using Olinda software. Results: Liver uptake was higher than all other organs, but was not blocked by pretreatment with letrozole. Mean SUVs in men were higher than in women, and brain uptake was blocked by letrozole. Male brain SUVs were also higher than all other organs (ranging from 0.48±0.05 in lungs to 1.5±0.13 in kidneys). Mean ovarian SUVs (3.08±0.7) were comparable to brain levels and higher than all other organs. Furthermore, ovarian SUVs In young women around the time of ovulation (midcycle) were significantly higher than those measured in the late luteal phase, while aging and cigarette smoking reduced ¹¹C-vorozole uptake. Conclusions: PET with ¹¹C-vorozole is useful for assessing physiological changes in estrogen synthesis capacity in the

  14. Maternal risk factors for abnormal placental growth: The national collaborative perinatal project

    PubMed Central

    Baptiste-Roberts, Kesha; Salafia, Carolyn M; Nicholson, Wanda K; Duggan, Anne; Wang, Nae-Yuh; Brancati, Frederick L

    2008-01-01

    Background Previous studies of maternal risk factors for abnormal placental growth have focused on placental weight and placental ratio as measures of placental growth. We sought to identify maternal risk factors for placental weight and two neglected dimensions of placental growth: placental thickness and chorionic plate area. Methods We conducted an analysis of 24,135 mother-placenta pairs enrolled in the National Collaborative Perinatal Project, a prospective cohort study of pregnancy and child health. We defined growth restriction as < 10th percentile and hypertrophy as > 90th percentile for three placental growth dimensions: placental weight, placental thickness and chorionic plate area. We constructed parallel multinomial logistic regression analyses to identify (a) predictors of restricted growth (vs. normal) and (b) predictors of hypertrophic growth (vs. normal). Results Black race was associated with an increased likelihood of growth restriction for placental weight, thickness and chorionic plate area, but was associated with a reduced likelihood of hypertrophy for these three placental growth dimensions. We observed an increased likelihood of growth restriction for placental weight and chorionic plate area among mothers with hypertensive disease at 24 weeks or beyond. Anemia was associated with a reduced likelihood of growth restriction for placental weight and chorionic plate area. Pre-pregnancy BMI and pregnancy weight gain were associated with a reduced likelihood of growth restriction and an increased likelihood of hypertrophy for all three dimensions of placental growth. Conclusion Maternal risk factors are either associated with placental growth restriction or placental hypertrophy not both. Our findings suggest that the placenta may have compensatory responses to certain maternal risk factors suggesting different underlying biological mechanisms. PMID:18811957

  15. Cytochrome Electron Transfer and Biomolecular Electronics.

    DTIC Science & Technology

    1988-06-22

    polarograms of cytochrome c3 "a) DvM: Desulfovibrio vulgaris Miyazaki F (solid line,rmeasured; dots, si ulated) .. b) DvH: Desulfovibrio vulgaris ...Miyazaki); 2. D. vulgaris (H ldenborough); 3. D. sulfurlcans (Norway) and % 4. D. gigas. The macroscopic redox potentials for each of the hemes in the...Structure of Cytochrome C 3 Four cytochromes C have been selected for study: 1. D. vulgaris (Miyazaki) DvM) ; 2. D. vulgaris (Hildenborough) (DvH); 3. D

  16. Estrogen receptor-beta mediates the protective effects of aromatase induction in the MMTV-Her-2/neu x aromatase double transgenic mice.

    PubMed

    Nair, Hareesh B; Perla, Rao P; Kirma, Nameer B; Krishnegowda, Naveen K; Ganapathy, Manonmani; Rajhans, Rajib; Nair, Sujit S; Saikumar, Pothana; Vadlamudi, Ratna K; Tekmal, Rajeshwar Rao

    2012-04-01

    Breast cancers amplified for the tyrosine kinase receptor Her-2/neu constitute ~30% of advanced breast cancer cases, and are characterized by hormone independence and aggressive growth, implicating this pathway in breast oncogenesis. The induction of Her-2/neu leads to tumor development in 60% of transgenic mice. We have previously examined the effects of estrogen in the MMTV-Her-2/neu background by generating the MMTV-Her-2/neu x aromatase double transgenic mouse strain. MMTV-Her-2/neu x aromatase mice developed fewer mammary tumors than the Her-2/neu parental strain. Our present data show the induction of several estrogen-related genes, including the tumor suppressors BRCA1 and p53, and a decrease in several angiogenic factors. The phosphorylated forms of MAPK p42/44 and AKT were lower in the MMTV-Her-2/neu x aromatase double transgenic mice compared to the MMTV-Her-2/neu parental strain; conversely, phospho-p38 levels were higher in the double transgenic strain. The ERβ-selective antagonist THC reversed these changes. The regulation of these factors by ERβ was confirmed in clones of MCF7 breast cancer cells overexpressing Her-2/neu in combination with ERβ, suggesting that ERβ may play a direct role in regulating MAPK and AKT pathways. In summary, the data suggest that ERβ may play a major role in decreasing tumorigenesis and that it may affect breast cancer cell proliferation and survival by altering MAPK and AKT activation as well as modulation of tumor suppressor and angiogenesis factors. Treatment with selective ERβ agonist may provide therapeutic advantages for the treatment and prevention of breast cancer.

  17. Bidirectional Transfer Study of Polystyrene Nanoparticles across the Placental Barrier in an ex Vivo Human Placental Perfusion Model

    PubMed Central

    Grafmueller, Stefanie; Manser, Pius; Diener, Liliane; Diener, Pierre-André; Maeder-Althaus, Xenia; Maurizi, Lionel; Jochum, Wolfram; Krug, Harald F.; Buerki-Thurnherr, Tina; von Mandach, Ursula

    2015-01-01

    Background Nanoparticle exposure in utero might not be a major concern yet, but it could become more important with the increasing application of nanomaterials in consumer and medical products. Several epidemiologic and in vitro studies have shown that nanoparticles can have potential toxic effects. However, nanoparticles also offer the opportunity to develop new therapeutic strategies to treat specifically either the pregnant mother or the fetus. Previous studies mainly addressed whether nanoparticles are able to cross the placental barrier. However, the transport mechanisms underlying nanoparticle translocation across the placenta are still unknown. Objectives In this study we examined which transport mechanisms underlie the placental transfer of nanoparticles. Methods We used the ex vivo human placental perfusion model to analyze the bidirectional transfer of plain and carboxylate modified polystyrene particles in a size range between 50 and 300 nm. Results We observed that the transport of polystyrene particles in the fetal to maternal direction was significantly higher than for the maternal to fetal direction. Regardless of their ability to cross the placental barrier and the direction of perfusion, all polystyrene particles accumulated in the syncytiotrophoblast of the placental tissue. Conclusions Our results indicate that the syncytiotrophoblast is the key player in regulating nanoparticle transport across the human placenta. The main mechanism underlying this translocation is not based on passive diffusion, but is likely to involve an active, energy-dependent transport pathway. These findings will be important for reproductive toxicology as well as for pharmaceutical engineering of new drug carriers. Citation Grafmueller S, Manser P, Diener L, Diener PA, Maeder-Althaus X, Maurizi L, Jochum W, Krug HF, Buerki-Thurnherr T, von Mandach U, Wick P. 2015. Bidirectional transfer study of polystyrene nanoparticles across the placental barrier in an ex vivo human

  18. Heterogeneous models place the root of the placental mammal phylogeny.

    PubMed

    Morgan, Claire C; Foster, Peter G; Webb, Andrew E; Pisani, Davide; McInerney, James O; O'Connell, Mary J

    2013-09-01

    Heterogeneity among life traits in mammals has resulted in considerable phylogenetic conflict, particularly concerning the position of the placental root. Layered upon this are gene- and lineage-specific variation in amino acid substitution rates and compositional biases. Life trait variations that may impact upon mutational rates are longevity, metabolic rate, body size, and germ line generation time. Over the past 12 years, three main conflicting hypotheses have emerged for the placement of the placental root. These hypotheses place the Atlantogenata (common ancestor of Xenarthra plus Afrotheria), the Afrotheria, or the Xenarthra as the sister group to all other placental mammals. Model adequacy is critical for accurate tree reconstruction and by failing to account for these compositional and character exchange heterogeneities across the tree and data set, previous studies have not provided a strongly supported hypothesis for the placental root. For the first time, models that accommodate both tree and data set heterogeneity have been applied to mammal data. Here, we show the impact of accurate model assignment and the importance of data sets in accommodating model parameters while maintaining the power to reject competing hypotheses. Through these sophisticated methods, we demonstrate the importance of model adequacy, data set power and provide strong support for the Atlantogenata over other competing hypotheses for the position of the placental root.

  19. Histopathological placental lesions in mild gestational hyperglycemic and diabetic women

    PubMed Central

    2011-01-01

    Objective To investigate and compare the incidence of histopathological placental lesions in mild gestational hyperglycemia, gestational diabetes and overt diabetes at term and preterm gestation. Research design and methods One-hundred-and-thirty-one placental samples were collected from Diabetes mellitus (DM) positive screened patients. Two diagnostic tests, glycemic profile and 100 g oral glucose tolerance test (OGTT) in parallel identified 4 groups normoglycemic, mild gestational hyperglycemia (MGH), gestational DM (GDM) or overt DM (DM). Placental tissue specimens and sections from 4 groups were obtained by uniform random sampling and stained with hematoxylin-eosin. Results Placentas from MGH group presented 17 types of histopathological change and higher rates of syncytial nodes and endarteritis. GDM placentas presented only nine types of histopathological change, high rates of dysmaturity, low rates of calcification and no syncytial nodes. Overt DM placentas showed 22 types of histopathological change, 21 of which were present in the preterm period. There were histopathological similarities between MGH and DM placentas, but the former exhibited a higher incidence of endarteritis, which has been described as a "post-mortem" phenomenon. Conclusion Our results confirmed that the distinct placental changes associated with DM and MGH depend on gestational period during which the diabetic insult occurs. It may reasonably be inferred that subclinical maternal hyperglycemia during pregnancy, as showed in MGH group, is responsible for increased placental endarteritis, a postmortem lesion in the live fetus. PMID:21831283

  20. A higher-level MRP supertree of placental mammals

    PubMed Central

    Beck, Robin MD; Bininda-Emonds, Olaf RP; Cardillo, Marcel; Liu, Fu-Guo Robert; Purvis, Andy

    2006-01-01

    Background The higher-level phylogeny of placental mammals has long been a phylogenetic Gordian knot, with disagreement about both the precise contents of, and relationships between, the extant orders. A recent MRP supertree that favoured 'outdated' hypotheses (notably, monophyly of both Artiodactyla and Lipotyphla) has been heavily criticised for including low-quality and redundant data. We apply a stringent data selection protocol designed to minimise these problems to a much-expanded data set of morphological, molecular and combined source trees, to produce a supertree that includes every family of extant placental mammals. Results The supertree is well-resolved and supports both polyphyly of Lipotyphla and paraphyly of Artiodactyla with respect to Cetacea. The existence of four 'superorders' – Afrotheria, Xenarthra, Laurasiatheria and Euarchontoglires – is also supported. The topology is highly congruent with recent (molecular) phylogenetic analyses of placental mammals, but is considerably more comprehensive, being the first phylogeny to include all 113 extant families without making a priori assumptions of suprafamilial monophyly. Subsidiary analyses reveal that the data selection protocol played a key role in the major changes relative to a previously published higher-level supertree of placentals. Conclusion The supertree should provide a useful framework for hypothesis testing in phylogenetic comparative biology, and supports the idea that biogeography has played a crucial role in the evolution of placental mammals. Our results demonstrate the importance of minimising poor and redundant data when constructing supertrees. PMID:17101039

  1. Genomics, biogeography, and the diversification of placental mammals

    PubMed Central

    Wildman, Derek E.; Uddin, Monica; Opazo, Juan C.; Liu, Guozhen; Lefort, Vincent; Guindon, Stephane; Gascuel, Olivier; Grossman, Lawrence I.; Romero, Roberto; Goodman, Morris

    2007-01-01

    Previous molecular analyses of mammalian evolutionary relationships involving a wide range of placental mammalian taxa have been restricted in size from one to two dozen gene loci and have not decisively resolved the basal branching order within Placentalia. Here, on extracting from thousands of gene loci both their coding nucleotide sequences and translated amino acid sequences, we attempt to resolve key uncertainties about the ancient branching pattern of crown placental mammals. Focusing on ≈1,700 conserved gene loci, those that have the more slowly evolving coding sequences, and using maximum-likelihood, Bayesian inference, maximum parsimony, and neighbor-joining (NJ) phylogenetic tree reconstruction methods, we find from almost all results that a clade (the southern Atlantogenata) composed of Afrotheria and Xenarthra is the sister group of all other (the northern Boreoeutheria) crown placental mammals, among boreoeutherians Rodentia groups with Lagomorpha, and the resultant Glires is close to Primates. Only the NJ tree for nucleotide sequences separates Rodentia (murids) first and then Lagomorpha (rabbit) from the other placental mammals. However, this nucleotide NJ tree still depicts Atlantogenata and Boreoeutheria but minus Rodentia and Lagomorpha. Moreover, the NJ tree for amino acid sequences does depict the basal separation to be between Atlantogenata and a Boreoeutheria that includes Rodentia and Lagomorpha. Crown placental mammalian diversification appears to be largely the result of ancient plate tectonic events that allowed time for convergent phenotypes to evolve in the descendant clades. PMID:17728403

  2. Human placental lactogen decreases regional blood flow in anesthetized pigs.

    PubMed

    Grossini, E; Molinari, C; Battaglia, A; Mary, D A S G; Ribichini, F; Surico, N; Vacca, G

    2006-01-01

    In 22 pigs anesthetized with sodium pentobarbitone, changes in blood flow caused by infusion of human placental lactogen into the left renal, external iliac, and anterior descending coronary arteries were assessed using electromagnetic flowmeters. In 17 pigs, infusion of human placental lactogen whilst keeping the heart rate and arterial pressure constant decreased coronary, renal and iliac flow. In 5 additional pigs, increasing the dose of human placental lactogen produced a dose-related decrease in regional blood flow. The mechanisms of the above response were studied in 15 of the 17 pigs by repeating the experiment of infusion. The human placental lactogen-induced decrease in regional blood flow was not affected by blockade of cholinergic receptors (5 pigs) or of alpha-adrenergic receptors (5 pigs), but it was abolished by blockade of beta2-adrenergic receptors (5 pigs). The present study showed that intra-arterial infusion of human placental lactogen primarily decreased coronary, renal and iliac blood flow. The mechanism of this response was shown to be due to the inhibition of a vasodilatory beta2-adrenergic receptor-mediated effect.

  3. Nitric oxide and oxidative stress in placental explant cultures.

    PubMed

    Goncalves, Juvic M; Casart, Ysabel C; Camejo, María I

    2016-01-01

    Placental explant culture, and cellular cytolysis and cellular differentiation have been previously studied. However, oxidative stress and nitric oxide profiles have not been evaluated in these systems. The aim of this study was to determine the release of lipid peroxidation and nitric oxide from placental explants cultured over a seven day period. Placental explants were maintained for seven days in culture and the medium was changed every 24 hours. The response was assessed in terms of syncytiotrophoblast differentiation (human chorionic gonadotropin, hCG), cellular cytolysis (lactate dehydrogenase, LDH), oxidative stress (thiobarbituric acid reactive substances, TBARS), and nitric oxide (NO). Levels of hCG increased progressively from day two to attain its highest level on days four and five after which it decreased gradually. In contrast, the levels of LDH, TBARS, and NO were elevated in the early days of placental culture when new syncytiotrophoblast from cytotrophoblast were forming and also in the last days of culture when tissue was declining. In conclusion, the levels of NO and lipid peroxidation follow a pattern similar to LDH and contrary to hCG. Future placental explant studies to evaluate oxidative stress and NO should consider the physiological changes inherent during the time of culture.

  4. Estrogen receptor alpha is required for mammary development and the induction of mammary hyperplasia and epigenetic alterations in the aromatase transgenic mice.

    PubMed

    Tekmal, Rajeshwar Rao; Liu, Ya-Guang; Nair, Hareesh B; Jones, Jeremy; Perla, Rao P; Lubahn, Dennis B; Korach, Kenneth S; Kirma, Nameer

    2005-05-01

    Aromatase transgenic mice exhibit hyperplastic and dysplastic changes, attesting to the importance of local estrogen in breast carcinogenesis. These mice also show increased levels of the estrogen receptor alpha and beta (ERalpha, ERbeta) suggesting that this receptor may play an important role in the initiation of estrogen-mediated mammary hyperplasia observed in these mice. To address the specific role of ERalpha in the mammary development and in the induction of estrogen-mediated hyperplasia in aromatase transgenic mice, we have generated MMTV-aromatase x ERalpha knockout cross (referred as aromatase/ERKO). Even though ERbeta is expressed in aromatase/ERKO mice, lack of ERalpha leads to impaired mammary growth in these mice. The data suggest that ERalpha plays an important role in the mammary gland development as well as in the induction of mammary hyperplasia in aromatase transgenic mice. Lack of ERalpha expression in the aromatase/ERKO mice resulted in a decrease in the expression of Cyclin D1, PCNA and TGFbeta relative to the aromatase parental strain. The studies involving aromatase/ERKO mice show that lack of ERalpha results in impaired mammary development even in the presence of continuous tissue estrogen, suggesting estrogen/ERalpha-mediated actions are critical for mammary development and carcinogenesis.

  5. Cytochrome P450-activated prodrugs

    PubMed Central

    Ortiz de Montellano, Paul R

    2013-01-01

    A prodrug is a compound that has negligible, or lower, activity against a specified pharmacological target than one of its major metabolites. Prodrugs can be used to improve drug delivery or pharmacokinetics, to decrease toxicity, or to target the drug to specific cells or tissues. Ester and phosphate hydrolysis are widely used in prodrug design because of their simplicity, but such approaches are relatively ineffective for targeting drugs to specific sites. The activation of prodrugs by the cytochrome P450 system provides a highly versatile approach to prodrug design that is particularly adaptable for targeting drug activation to the liver, to tumors or to hypoxic tissues. PMID:23360144

  6. Effects of aromatase inhibitor on menopausal hyperplasia in a case of obesity.

    PubMed

    Koloszar, S; Pal, Z; Kereszturi, A; Vajda, G; Pal, A; Daru, J

    2012-02-01

    The aromatase inhibitor anastrazole proved effective in the treatment of endometrial hyperplasia and postmenopausal bleeding in an obese 65-year-old woman with high operative risk. During anastrazole administration for 12 months, the endometrial thickness decreased from 9.8 mm to 2.4 mm and the control endometrial histology showed an atrophic endometrium. Uterine bleeding did not occur in the post-treatment, 3-year follow-up period. The endometrial thicknesses measured yearly by ultrasonography were 2.9, 3.5 and 3.3 mm. The plasma estradiol levels increased from < 73 pmol/l post-treatment to 112, 98 and 103 pmol/l. This case demonstrates that long-term aromatase inhibitor treatment can result in a refractory status of the endometrium and the estradiol produced in the adipose tissue does not exert a proliferative effect.

  7. Estradiol as an anti-aromatase agent in human breast cancer cells.

    PubMed

    Pasqualini, J R; Chetrite, G S

    2006-01-01

    Estradiol (E(2)) is an important risk factor in the development and progression of breast cancer. However, a "direct effect" of E(2) in breast cancerization has not yet been demonstrated. The estrogen receptor complex can mediate the activation of oncogens, proto-oncogens, nuclear proteins and other target genes that can be involved in the transformation of normal to cancerous cells. Breast cancer cells possess all the enzymes (sulfatase, aromatase, 17beta-hydroxysteroid dehydrogenase (17beta-HSD)) necessary for the local bioformation of E(2). In the last years, many studies have shown that treatment of breast cancer patients using anti-aromatase agents has beneficial therapeutic effects. The aromatase activity is very low in most breast cancer cells but was significantly increased in a hormone-dependent breast cancer cell line: the MCF-7aro, using the aromatase cDNA transfection and G-418 (neomycin) selection. In the present study, we explore the effect of E(2) on the aromatase activity of this cell line. The MCF-7aro cell line was a gift from Dr. S. Chen (Beckman Research Institute, Duarte, U.S.A.). For experiments the cells were stripped of endogenous steroids and incubated with physiological concentrations of [(3)H]-testosterone (5 x 10(-9)mol/l) alone or in the presence of E(2) (5 x 10(-5), 5 x 10(-7) and 5 x 10(-9)mol/l) for 24h at 37 degrees C. The cellular radioactivity uptake was determined in the ethanolic supernatant and the DNA content in the remaining pellet. [(3)H]-E(2), [(3)H]-estrone ([(3)H]-E(1)) and [(3)H]-testosterone were characterized by thin layer chromatography and quantified using the corresponding standard. It was observed that [(3)H]-testosterone is converted mainly into [(3)H]-E(2) and not to E(1), which suggests very low or absence of oxidative 17beta-HSD (type 2) activity in these experimental conditions. The aromatase activity, corresponding to the conversion of [(3)H]-testosterone to [(3)H]-E(2) after 24h, is relatively high, since

  8. Catalysis by cytochrome P-450 of an oxidative reaction in xenobiotic aldehyde metabolism: deformylation with olefin formation.

    PubMed Central

    Roberts, E S; Vaz, A D; Coon, M J

    1991-01-01

    As we have briefly described elsewhere, cytochrome P-450 catalyzes the oxidative deformylation of cyclohexane carboxaldehyde to yield cyclohexene and formic acid in a reaction believed to involve a peroxyhemiacetal-like adduct formed between the substrate and molecular oxygen-derived hydrogen peroxide. This reaction is a useful model for the demethylation reactions catalyzed by the steroidogenic P-450s, aromatase, and lanosterol demethylase. In the present study, the cytochrome P-450-catalyzed formation of olefinic products from a series of xenobiotic aldehydes has been demonstrated. Isobutyraldehyde and trimethylacetaldehyde, but not propionaldehyde, are converted to the predicted olefinic products, suggesting a requirement for branching at the alpha carbon. In addition, the four C5 aldehydes of similar hydrophobicity were compared for their ability to undergo the reaction. The straight-chain valeraldehyde gave no olefinic products with five different rabbit liver microsomal P-450 isozymes. However, increasing activity was seen with the other isomers in the order of isovaleraldehyde, 2-methylbutyraldehyde, and trimethylacetaldehyde, with all of the P-450 cytochromes. The catalytic rate with trimethylacetaldehyde is highest with antibiotic-inducible P-450 form 3A6, followed by phenobarbital-inducible form 2B4 and ethanol-inducible form 2E1. Citronellal, a beta-branched aldehyde that is found in many essential oils and is widely used as an odorant and a flavorant, was found to undergo the oxidative deformylation reaction to yield 2,6-dimethyl-1,5-heptadiene, but only with P-450 2B4. The oxidative cleavage reaction with olefin formation appears to be widespread, as judged by the variety of aldehydes that serve as substrates and of P-450 cytochromes that serve as catalysts. PMID:1924356

  9. Influence of aromatase inhibition on the bone-protective effects of testosterone.

    PubMed

    Beck, Darren T; Yarrow, Joshua F; Beggs, Luke A; Otzel, Dana M; Ye, Fan; Conover, Christine F; Miller, Julie R; Balaez, Alexander; Combs, Sarah M; Leeper, Alicia M; Williams, Alyssa A; Lachacz, Stephanie A; Zheng, Nigel; Wronski, Thomas J; Borst, Stephen E

    2014-11-01

    The influence of the aromatase enzyme in androgen-induced bone maintenance after skeletal maturity remains somewhat unclear. Our purpose was to determine whether aromatase activity is essential to androgen-induced bone maintenance. Ten-month-old male Fisher 344 rats (n = 73) were randomly assigned to receive Sham surgery, orchiectomy (ORX), ORX + anastrozole (AN; aromatase inhibitor), ORX + testosterone-enanthate (TE, 7.0 mg/wk), ORX + TE + AN, ORX + trenbolone-enanthate (TREN; nonaromatizable, nonestrogenic testosterone analogue; 1.0 mg/wk), or ORX + TREN + AN. ORX animals exhibited histomorphometric indices of high-turnover osteopenia and reduced cancellous bone volume compared with Shams. Both TE and TREN administration suppressed cancellous bone turnover similarly and fully prevented ORX-induced cancellous bone loss. TE- and TREN-treated animals also exhibited greater femoral neck shear strength than ORX animals. AN co-administration slightly inhibited the suppression of bone resorption in TE-treated animals but did not alter TE-induced suppression of bone formation or the osteogenic effects of this androgen. In TREN-treated animals, AN co-administration produced no discernible effects on cancellous bone turnover or bone volume. ORX animals also exhibited reduced levator ani/bulbocavernosus (LABC) muscle mass and elevated visceral adiposity. In contrast, TE and TREN produced potent myotrophic effects in the LABC muscle and maintained fat mass at the level of Shams. AN co-administration did not alter androgen-induced effects on muscle or fat. In conclusion, androgens are able to induce direct effects on musculoskeletal and adipose tissue, independent of aromatase activity.

  10. Neural stem cell sex dimorphism in aromatase (CYP19) expression: a basis for differential neural fate

    PubMed Central

    Waldron, Jay; McCourty, Althea; Lecanu, Laurent

    2010-01-01

    Purpose Neural stem cell (NSC) transplantation and pharmacologic activation of endogenous neurogenesis are two approaches that trigger a great deal of interest as brain repair strategies. However, the success rate of clinical attempts using stem cells to restore neurologic functions altered either after traumatic brain injury or as a consequence of neurodegenerative disease remains rather disappointing. This suggests that factors affecting the fate of grafted NSCs are largely understudied and remain to be characterized. We recently reported that aging differentially affects the neurogenic properties of male and female NSCs. Although the sex steroids androgens and estrogens participate in the regulation of neurogenesis, to our knowledge, research on how gender-based differences affect the capacity of NSCs to differentiate and condition their neural fate is lacking. In the present study, we explored further the role of cell sex as a determining factor of the neural fate followed by differentiating NSCs and its relationship with a potential differential expression of aromatase (CYP19), the testosterone-metabolizing enzyme. Results Using NSCs isolated from the subventricular zone of three-month-old male and female Long-Evans rats and maintained as neurospheres, we showed that differentiation triggered by retinoic acid resulted in a neural phenotype that depends on cell sex. Differentiated male NSCs mainly expressed markers of neuronal fate, including βIII-tubulin, microtubule associated protein 2, growth-associated protein 43, and doublecortin. In contrast, female NSCs essentially expressed the astrocyte marker glial fibrillary acidic protein. Quantification of the expression of aromatase showed a very low level of expression in undifferentiated female NSCs, whereas aromatase expression in male NSCs was 14-fold greater than the female level. Conclusion Our results confirm our previous data that the neural phenotype acquired by differentiating NSCs largely depends on

  11. Design, synthesis and aromatase inhibitory activities of novel indole-imidazole derivatives.

    PubMed

    Wang, Rui; Shi, Hong-Fan; Zhao, Jing-Feng; He, Yan-Ping; Zhang, Hong-Bin; Liu, Jian-Ping

    2013-03-15

    A series of novel indole-imidazole derivatives have been prepared and evaluated in vitro on the aromatase inhibitory activities. The results suggested that proton or a small electron-withdrawing group at para-position of the phenyl ring would enhance the inhibitory activities and any bulky group should be avoided in order to keep a relative small volume for this kind of molecules.

  12. Aromatase Inhibitors for Endometriosis-Associated Infertility; Do We Have Sufficient Evidence?

    PubMed Central

    Abu Hashim, Hatem

    2016-01-01

    Orally active aromatase inhibitors (AIs) have gained attention for treatment of infertile women with endometriosis in whom aromatase p450 is aberrantly expressed. This review aimed to critically appraise and summarize the available evidence concerning the use of AIs for management of endometriosis-associated infertility. PubMed was searched to May 2015 with the following key words: endometriosis, infertility and aromatase. Priority was given for randomized controlled trials (RCTs) followed by other study designs. Main outcome measures were as follows: rates of clinical pregnancy, miscarriage and live birth as well as endocrine outcomes. Eighty-two abstracts were screened and six original articles were included. A RCT demonstrated that post-operative letrozole treatment did not improve spontaneous pregnancy rate. Another RCT reported no superiority of letrozole superovulation over clomiphene citrate (each combined with intrauterine insemination) in minimalmild endometriosis and previous laparoscopic treatment. Anastrozole significantly inhibited the growth of endometriotic cells and their estrogen production in culture. In assisted reproductive technology (ART) cycles, dual suppression (Agonist/anastrozole) was tested in a pilot study with a pregnancy rate of 45% however, high pregnancy loss (30%) occurred. A retrospective study showed that letrozole may improve endometrial receptivity in endometriotic patients undergoing in vitro fertilization (IVF). An opposite view from an in vitro study showed lower estradiol production and aromatase expression in cultured granulosa cells from endometriotic women undergoing IVF and marked reduction under letrozole. In conclusion, current evidence is limited. More trials are warranted to enhance our knowledge and provide a clear and unequivocal evidence to guide our clinical management of infertile women with endometriosis using AIs. PMID:27695608

  13. Aromatase is expressed and active in the rainbow trout oocyte during final oocyte maturation.

    PubMed

    Gohin, Maella; Bodinier, Pascal; Fostier, Alexis; Chesnel, Franck; Bobe, Julien

    2011-07-01

    While it is generally well accepted that the ovarian follicular sites of estradiol-17β (E2) synthesis are restricted to somatic cells, the possible contribution of the germinal compartment has received little or no attention in teleosts. In order to demonstrate the expression of ovarian aromatase in the oocyte, cyp19a1a mRNA was studied in ovarian follicles by in situ hybridization. In addition, the expression of cyp19a1a was studied in both somatic and germinal compartments of the ovarian follicle in rainbow trout (Oncorhynchus mykiss) during final oocyte maturation (i.e., maturational competence acquisition and subsequent meiosis resumption) by real-time PCR. The enzymatic activity of ovarian aromatase was also studied in both somatic and germinal compartments of the ovarian follicle. Finally, E2 levels were monitored in follicle-enclosed oocytes throughout the pre-ovulatory period. We were able to demonstrate a significant ovarian aromatase expression and activity in the late vitellogenic oocyte. Furthermore, a dramatic decrease in aromatase expression and activity occurs in the oocyte during late oogenesis, concomitantly with the trend observed in surrounding follicular layers. We also report an unexpected increase of E2 levels in the oocyte during the pre-ovulatory period. To our knowledge, these observations are reported for the first time in any teleost species. Together, our data support the hypothesis of the participation of the germinal compartment in follicular estrogen synthesis and a biological role of E2 during oocyte and/or early embryo development.

  14. Design and synthesis of a new type of non steroidal human aromatase inhibitors.

    PubMed

    Sonnet, P; Guillon, J; Enguehard, C; Dallemagne, P; Bureau, R; Rault S Auvray, P; Moslemi, S; Sourdiane, P; Galopin, S; Séralini, G E

    1998-05-05

    The structure-activity relationship study of one of recently described aromatase inhibitors, compound 1 (MR20814), allowed us to design some related derivatives as potential new inhibitors. Among those we synthesized, chlorophenylpyridylmethylenetetrahydroindolizinone 5 (MR20492) exhibited in vitro a ten-fold higher inhibition of the enzyme (IC50 = 0.2 +/- 0.0 microM and Ki = 10.3 +/- 3.3 nM).

  15. Blocking Endogenous Leukemia Inhibitory Factor During Placental Development in Mice Leads to Abnormal Placentation and Pregnancy Loss

    PubMed Central

    Winship, Amy; Correia, Jeanne; Krishnan, Tara; Menkhorst, Ellen; Cuman, Carly; Zhang, Jian-Guo; Nicola, Nicos A.; Dimitriadis, Evdokia

    2015-01-01

    The placenta forms the interface between the maternal and fetal circulation and is critical for the establishment of a healthy pregnancy. Specialized trophoblast cells derived from the embryonic trophectoderm play a pivotal role in the establishment of the placenta. Leukemia inhibitory factor (LIF) is one of the predominant cytokines present in the placenta during early pregnancy. LIF has been shown to regulate trophoblast adhesion and invasion in vitro, however its precise role in vivo is unknown. We hypothesized that LIF would be required for normal placental development in mice. LIF and LIFRα were immunolocalized to placental trophoblasts and fetal vessels in mouse implantation sites during mid-gestation. Temporally blocking LIF action during specific periods of placental development via intraperitoneal administration of our specific LIFRα antagonist, PEGLA, resulted in abnormal placental trophoblast and vascular morphology and reduced activated STAT3 but not ERK. Numerous genes regulating angiogenesis and oxidative stress were altered in the placenta in response to LIF inhibition. Pregnancy viability was also significantly compromised in PEGLA treated mice. Our data suggest that LIF plays an important role in placentation in vivo and the maintenance of healthy pregnancy. PMID:26272398

  16. Clinical use of placental hormones in pregnancy management.

    PubMed

    De Bonis, M; Vellucci, F L; Di Tommaso, M; Voltolini, C; Torricelli, M; Petraglia, F

    2012-09-01

    Across human pregnancy, placenta represents a transit of oxygen and nutrients from the mother to the fetus and actively produces a large number of hormones that serve to regulate and balance maternal and fetal physiology. An abnormal secretion of placental hormones may be part of the pathogenesis of the main obstetric syndrome, from early to late pregnancy, in particular chromosomopathies, miscarriage, gestational trophoblastic diseases, preeclampsia, gestational diabetes, and pre-term delivery. The possibility to measure placental hormones represents an important tool not only for the diagnosis and management of gestational disorders, but it is also fundamental in the early identification of women at risk for these pregnancy complications. In the last decades, the use of ultrasound examination has provided additional biophysical markers, improving the early diagnosis of gestational diseases. In conclusion, while few placental hormones have sufficient sensitivity for clinical application, there are promising new biochemical and biophysical markers that, if used in combination, may provide a valid screening tool.

  17. Parallel adaptive radiations in two major clades of placental mammals.

    PubMed

    Madsen, O; Scally, M; Douady, C J; Kao, D J; DeBry, R W; Adkins, R; Amrine, H M; Stanhope, M J; de Jong, W W; Springer, M S

    2001-02-01

    Higher level relationships among placental mammals, as well as the historical biogeography and morphological diversification of this group, remain unclear. Here we analyse independent molecular data sets, having aligned lengths of DNA of 5,708 and 2,947 base pairs, respectively, for all orders of placental mammals. Phylogenetic analyses resolve placental orders into four groups: Xenarthra, Afrotheria, Laurasiatheria, and Euarchonta plus Glires. The first three groups are consistently monophyletic with different methods of analysis. Euarchonta plus Glires is monophyletic or paraphyletic depending on the phylogenetic method. A unique nine-base-pair deletion in exon 11 of the BRCA1 gene provides additional support for the monophyly of Afrotheria, which includes proboscideans, sirenians, hyracoids, tubulidentates, macroscelideans, chrysochlorids and tenrecids. Laurasiatheria contains cetartiodactyls, perissodactyls, carnivores, pangolins, bats and eulipotyphlan insectivores. Parallel adaptive radiations have occurred within Laurasiatheria and Afrotheria. In each group, there are aquatic, ungulate and insectivore-like forms.

  18. Human placental coated vesicles contain receptor-bound transferrin.

    PubMed Central

    Booth, A G; Wilson, M J

    1981-01-01

    Human placental coated vesicles have been purified by a method involving sucrose-density-gradient centrifugation and treatment with wheat-germ agglutinin. These preparations were free of contamination by placental microvillus fragments. Crossed immunoelectrophoresis demonstrated that the coated vesicles contained a single serum protein, which was identified as transferrin. This transferrin was only observed after the vesicles were treated with a non-ionic detergent, and its behaviour during crossed hydrophobic-interaction immunoelectrophoresis suggested that a large proportion of it was receptor-bound. No other serum proteins, including immunoglobulin G, could be detected in these preparations. Receptor-bound transferrin was the only antigen common to placental coated vesicles and microvilli, implying that other plasma-membrane proteins are excluded from the region of membrane involved in coated-vesicle formation. Images PLATE 2 PLATE 1 Fig. 1. Fig. 2. Fig. 3. PMID:6272755

  19. Placental lesions in a case of DiGeorge sequence.

    PubMed

    Fulcheri, E; Gualco, M; Delfino, F; Pantarotto, M F

    2006-01-01

    This work describes some placental alterations found in a partial form of DiGeorge sequence, namely, hypoplasia of a cord artery with internal calcification of an extensive endoluminal thrombosis, and widespread calcification of microthrombi in the arteries of the second and third order villous branches. Hypoplasia of a cord artery is a relatively rare event, and is also associated with malformations of the gastroenteric and cardiovascular system, as sometimes described in the DiGeorge sequence. Interesting placental alterations are reported and their likely physiopathologic basis and pathogenic correlation discussed in order to give a better and more comprehensive picture of the DiGeorge sequence in which the correlated placental alterations are not sufficiently known.

  20. Activity of anandamide (AEA) metabolic enzymes in rat placental bed.

    PubMed

    Fonseca, B M; Battista, N; Correia-da-Silva, G; Rapino, C; Maccarrone, M; Teixeira, N A

    2014-11-01

    Endocannabinoids are endogenous lipid mediators, with anandamide (AEA) being the first member identified. It is now widely accepted that AEA influences early pregnancy events and its levels, which primarily depend on its synthesis by an N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD) and degradation by a fatty acid amide hydrolase (FAAH), must be tightly regulated. Previous studies demonstrated that AEA levels require in situ regulation of these respective metabolic enzymes, and thus, any disturbance in AEA levels may impact maternal remodeling processes occurring during placental development. In this study, the activities of the AEA-metabolic enzymes that result in the establishment of proper local AEA levels during rat gestation were examined. Here, we demonstrate that during placentation NAPE-PLD and FAAH activities change in a temporal manner. Our findings suggest that NAPE-PLD and FAAH create the appropriate AEA levels required for tissue remodeling in the placental bed, a process essential to pregnancy maintenance.

  1. Cytochrome c Adducts with PCB Quinoid Metabolites

    PubMed Central

    Li, Miao; Teesch, Lynn M.; Murry, Daryl J.; Pope, R. Marshal; Li, Yalan; Robertson, Larry W.; Ludewig, Gabriele

    2015-01-01

    PCBs are a group of 209 individual congeners widely used as industrial chemicals. PCBs are found as by-products in dye and paint manufacture and are legacy, ubiquitous and persistent as human and environmental contaminants. PCBs with fewer chlorine atoms may be metabolized to hydroxy- and dihydroxy- metabolites and further oxidized to quinoid metabolites both in vitro and in vivo. Specifically, quinoid metabolites may form adducts on nucleophilic sites within cells. We hypothesized that the PCB-quinones covalently bind to cytochrome c and thereby cause defects in the function of cytochrome c. In this study synthetic PCB quinones (2-(4’-chlorophenyl)-1,4-benzoquinone, 2-(3’, 5’-dichlorophenyl)-1,4-benzoquinone, 2-(3’,4’, 5’-trichlorophenyl)-1,4-benzoquinone, and 2-(4’-chlorophenyl)-3,6-dichloro-1,4-benzoquinone) were incubated with cytochrome c, and adducts were detected by LC-MS and MALDI TOF. SDS PAGE gel electrophoresis was employed to separate the adducted proteins, while trypsin digestion and LC-MS/MS were applied to identify the amino acid binding sites on cytochrome c. Conformation change of cytochrome c after binding with PCB3-para-quinone was investigated by SYBYL-X simulation and cytochrome c function was examined. We found that more than one molecule of PCB-quinone may bind to one molecule of cytochrome c. Lysine and glutamic acid were identified as the predominant binding sites. Software simulation showed conformation changes of adducted cytochrome c. Additionally, cross-linking of cytochrome c was observed on the SDS PAGE gel. Cytochrome c was found to be in the reduced form after incubation with PCB quinones. These data provide evidence that the covalent binding of PCB quinone metabolites to cytochrome c may be included among the toxic effects of PCBs. PMID:26062463

  2. Synthesis of Triphenylethylene Bisphenols as Aromatase Inhibitors that Also Modulate Estrogen Receptors

    PubMed Central

    Lv, Wei; Liu, Jinzhong; Skaar, Todd C.; O'Neill, Elizaveta; Yu, Ge; Flockhart, David A.; Cushman, Mark

    2016-01-01

    A series of triphenylethylene bisphenol analogues of the selective estrogen receptor modulator (SERM) tamoxifen were synthesized and evaluated for their abilities to inhibit aromatase, bind to estrogen receptor-α (ER-α) and estrogen receptor-β (ER-β), and antagonize the activity of β-estradiol in MCF-7 human breast cancer cells. The long-range goal has been to create dual aromatase inhibitor (AI)/selective estrogen receptor modulators (SERMs). The hypothesis is that in normal tissue the estrogenic SERM activity of a dual AI/SERM could attenuate the undesired effects stemming from global estrogen depletion caused by the AI activity of a dual AI/SERM, while in breast cancer tissue the antiestrogenic SERM activity of a dual AI/SERM could act synergistically with AI activity to enhance the antiproliferative effect. The potent aromatase inhibitory activities and high ER-α and ER-β binding affinities of several of the resulting analogues, together with the facts that they antagonize β-estradiol in a functional assay in MCF-7 human breast cancer cells and they have no E/Z isomers, support their further development in order to obtain dual AI/SERM agents for breast cancer treatment. PMID:26704594

  3. Adjuvant therapy with tamoxifen compared to aromatase inhibitors for 257 male breast cancer patients.

    PubMed

    Eggemann, Holm; Ignatov, Atanas; Smith, Bobbie J; Altmann, Udo; von Minckwitz, Gunter; Röhl, Freidrich W; Jahn, Mark; Costa, Serban-Dan

    2013-01-01

    To determine the impact of adjuvant treatment with tamoxifen and aromatase inhibitors (AI) on the survival of men with breast cancer. We analyzed 257 male patients with hormone-receptor-positive breast cancer from numerous German population-based cancer registries treated with tamoxifen (N = 207) or aromatase inhibitors (N = 50). The median follow-up was 42.2 (range 2-115) months. Median age at diagnosis was 68 (range 36-91) years. Thirty-seven (17.9 %) patients treated with tamoxifen and 16 (32.0 %) patients treated with AI died (log rank p = 0.007). After the adjustment for the patient's age, tumor size, node status, and tumor grading, the AI treatment was linked to a 1.5-fold increase in risk of mortality compared to tamoxifen (HR 1.55; 95 % CI: 1.13-2.13; p = 0.007). The overall survival in male breast cancer was significantly better after adjuvant treatment with tamoxifen compared to an aromatase inhibitor. Tamoxifen should be considered as the treatment of choice for hormone-receptor-positive male breast cancer.

  4. Coadministrating luteolin minimizes the side effects of the aromatase inhibitor letrozole.

    PubMed

    Li, Fengjuan; Wong, Tsz Yan; Lin, Shu-mei; Chow, Simon; Cheung, Wing-hoi; Chan, Franky L; Chen, Shiuan; Leung, Lai K

    2014-11-01

    Aromatase inhibitors (AIs) have been used as adjuvant therapeutic agents for breast cancer. Their adverse side effect on blood lipid is well documented. Some natural compounds have been shown to be potential AIs. In the present study, we compared the efficacy of the flavonoid luteolin to the clinically approved AI letrozole (Femara; Novartis Pharmaceuticals, East Hanover, NJ) in a cell and a mouse model. In the in vitro experimental results for aromatase inhibition, the Ki values of luteolin and letrozole were estimated to be 2.44 µM and 0.41 nM, respectively. Both letrozole and luteolin appeared to be competitive inhibitors. Subsequently, an animal model was used for the comparison. Aromatase-expressing MCF-7 cells were transplanted into ovariectomized athymic mice. Luteolin was given by mouth at 5, 20, and 50 mg/kg, whereas letrozole was administered by intravenous injection. Similar to letrozole, luteolin administration reduced plasma estrogen concentrations and suppressed the xenograft proliferation. The regulation of cell cycle and apoptotic proteins-such as a decrease in the expression of Bcl-xL, cyclin-A/D1/E, CDK2/4, and increase in that of Bax-was about the same in both treatments. The most significant disparity was on blood lipids. In contrast to letrozole, luteolin increased fasting plasma high-density lipoprotein concentrations and produced a desirable blood lipid profile. These results suggested that the flavonoid could be a coadjuvant therapeutic agent without impairing the action of AIs.

  5. Inhibition of aromatase and α-amylase by flavonoids and proanthocyanidins from Sorghum bicolor bran extracts.

    PubMed

    Hargrove, James L; Greenspan, Phillip; Hartle, Diane K; Dowd, Christopher

    2011-01-01

    We compared the ability of simple flavonoids and proanthocyanidins in Sorghum bicolor bran extracts to inhibit enzymes in vitro. In particular, aromatase is a target for breast cancer therapy, and inhibition of α-amylase can reduce the glycemic effect of dietary starches. Proanthocyanidin-rich sumac sorghum bran extract inhibited α-amylase at a lower concentration (50% inhibitory concentration [IC₅₀]=1.4 μg/mL) than did proanthocyanidin-free black sorghum bran extract (IC₅₀=11.4 μg/mL). Sumac sorghum bran extract inhibited aromatase activity more strongly than black sorghum bran extract (IC₅₀=12.1 μg/mL vs. 18.8 μg/mL, respectively). Bovine serum albumin (BSA), which binds proanthocyanidins, reduced inhibition by sumac but not black sorghum bran extract. When separated on Sephadex LH-20, sumac sorghum proanthocyanidins inhibited both enzymes but showed reduced inhibition with BSA. Flavonoids from either cultivar had higher IC₅₀ values than proanthocyanidins, and BSA had little effect on their inhibition. Proanthocyanidins and simple flavonoids in LH-20 fractions both inhibited aromatase with mixed kinetics and affected K(m) and V(max). The results show that potential health benefits of sorghum bran may include actions of monomeric flavanoids as well as proanthocyanidins.

  6. The plant polyphenol butein inhibits testosterone-induced proliferation in breast cancer cells expressing aromatase.

    PubMed

    Wang, Yun; Chan, Franky L; Chen, Shiuan; Leung, Lai K

    2005-05-20

    Chalcones are precursor compounds for flavonoid synthesis in plants, and they can also be synthesized in laboratory. Previous study has documented some of the pharmacological applications of these compounds. Estrogen has long been associated with the initiation and promotion of breast cancer. Inhibiting estrogen synthesis can be effective in the prevention and treatment of the disease. Since most breast cancers received estrogen supplied from local tissues, we employed a breast cancer cell line expressing aromatase to screen for the inhibitory potentials of five hydroxychalcones, i.e. 2-hydroxychalcone, 2'-hydroxychalcone, 4-hydroxychalcone, 4,2',4'-trihydroxy-chalcone (isoquiritigenin), 3,4,2',4'-tetrahydroxychalcone (butein). In the preliminary results, butein was found to be the strongest inhibitor among the tested compounds, and its IC(50) value was 3.75 microM. Subsequent enzyme kinetic study revealed that butein acted on aromatase with a mixed type of inhibition and the K(i) value was determined to be 0.32 microM. Cell proliferation assay indicated that the cell number increased by 10 nM-testosterone treatment was significantly reduced by 5 microM butein, and the administration of flutamide could not reverse the effect. The present study illustrated that butein was an aromatase inhibitor and a potential natural alternative for the chemoprevention or therapy of breast cancer.

  7. Effects of nutrition relevant mixtures of phytoestrogens on steroidogenesis, aromatase, estrogen, and androgen activity.

    PubMed

    Taxvig, Camilla; Elleby, Anders; Sonne-Hansen, Katrine; Bonefeld-Jørgensen, Eva C; Vinggaard, Anne Marie; Lykkesfeldt, Anne E; Nellemann, Christine

    2010-01-01

    Phytoestrogens (PEs) are naturally occurring plant components produced in a large range of plants. They can induce biologic responses in vertebrates by mimicking or modulating the action or production of endogenous hormones. This study examined mixtures of 12 food relevant PEs for effects on steroid hormone production, aromatase activity, estrogenic activity, and for interaction with the androgen receptor. The results show that a mixture of all tested PEs increased estradiol production and decreased testosterone production in H295R human adrenal corticocarcinoma cells, indicating an induced aromatase activity. Furthermore, exposure of the H295R cells to isoflavonoids caused a decrease in testosterone production, and various mixtures of PEs significantly stimulated MCF-7 human breast adenocarcinoma cell growth and induced aromatase activity in JEG-3 choriocarcinoma cells. The estrogenic effect in the MCF7 cells of the isoflavonoid mixture and coumestrol was supported by an observed increase in progesterone receptor protein expression as well as a decreased ERalpha expression. Overall, the results support that nutrition-relevant concentrations of PEs both alone and in mixtures possess various endocrine disrupting effects, all of which need to be considered when assessing the effects on human health.

  8. Modulation of breast cancer cell survival by aromatase inhibiting hop (Humulus lupulus L.) flavonoids.

    PubMed

    Monteiro, Rosário; Faria, Ana; Azevedo, Isabel; Calhau, Conceição

    2007-01-01

    Hop flavonoids are being regarded as attractive molecules to prevent or treat certain forms of cancer. Studies have focused mainly on xanthohumol, the most abundant prenylated chalcone existing in hops extract. However, during the production of beer, or after its ingestion, xanthohumol originates different metabolites, among which isoxanthohumol and 8-prenylnaringenin. The aim of this work was to study the effect of the prenylflavonoids xanthohumol, isoxanthohumol and 8-prenylnaringenin on the breast cancer Sk-Br-3 cell line proliferation, apoptosis and activity of the enzyme aromatase (estrogen synthase). Aromatase activity was determined by a tritiated water assay, cell proliferation was assessed by [(3)H]thymidine incorporation, sulforhodamine B protein measurement and Ki-67 immunostaining and apoptosis was determined by TUNEL. Our results show that all tested prenylflavonoids were able to inhibit aromatase activity and thus, estrogen formation. Additionally, breast cancer cell line proliferation was decreased and apoptosis induced by all three compounds. The presence of 17beta-estradiol in treatment medium was able to revert the effect of the prenylflavonoids on cellular proliferation. These observations strengthen the idea that hop flavonoids may have anti-breast cancer effects and shed new light on a possible mechanism of action by which these effects occur, namely through their ability to decrease estrogen synthesis.

  9. Aromatase inhibitors and their future role in post-menopausal women with early breast cancer.

    PubMed Central

    Lønning, P. E.

    1998-01-01

    Anastrozole is the first aromatase inhibitor to show a significant survival advantage over megestrol acetate in post-menopausal women with advanced breast cancer. The rationale for extending the use of aromatase inhibitors to the treatment of early breast cancer is based on the efficacy observed in the advanced setting, combined with good tolerability and a convenient dosing regimen. Furthermore, oestrogen deprivation by ovarian ablation (similar to oestrogen antagonism with tamoxifen) is already established as an effective adjuvant treatment in premenopausal women with modality breast cancer. Anastrozole produces a profound suppression of plasma oestrogen levels which is greater than that obtained with earlier aromatase inhibitors (formestane, aminoglutethimide) or megestrol acetate. This could account for the differences in clinical efficacy seen between anastrozole and megestrol acetate. In terms of benefits over other endocrine agents, anastrozole causes significantly less weight gain than megestrol acetate; it does not have the partial agonist activity of tamoxifen, and is unlikely to lead to tumour stimulation in patients resistant to tamoxifen or to exert proliferative effects on the endometrium. The lack of oestrogen agonist activity, however, may possibly have detrimental effects on bone mineral density and blood lipid profile. Current clinical trials are investigating the efficacy and safety of anastrozole in the early breast cancer setting. The results of these trials will help to determine whether anastrozole has any benefits over tamoxifen, the current treatment of choice in post-menopausal women with early breast cancer. PMID:9741783

  10. Regulation of Baboon Fetal Ovarian Development by Placental Estrogen: Onset of Puberty Is Delayed in Offspring Deprived of Estrogen In Utero1

    PubMed Central

    Pepe, Gerald J.; Lynch, Terrie J.; Albrecht, Eugene D.

    2013-01-01

    ABSTRACT Using the baboon as a model for studies of human reproductive biology, we previously showed that placental estrogen regulates fetal ovarian follicle development. In this study, offspring of baboons untreated or treated in utero with the aromatase inhibitor letrozole (estradiol reduced >95%) or letrozole and estradiol were reared to adulthood to determine whether estrogen programming of the fetal ovary impacted puberty and reproduction in adulthood. All offspring exhibited normal growth and blood pressure/chemistries. Puberty onset in untreated baboons (43.2 ± 1.4 mo) was delayed (P < 0.01) in animals of letrozole-treated mothers (49.0 ± 1.2 mo) and normal in offspring of mothers treated with letrozole and estradiol (42.7 ± 0.8 mo). During the first 2 yr postmenarche, menstrual cycles in estrogen-suppressed animals (43.2 ± 1.3 days) were longer (P < 0.05) than in untreated baboons (38.3 ± 0.5 days) or those treated with letrozole and estrogen (39.6 ± 0.8 days). Moreover, in estrogen-suppressed offspring, serum levels of estradiol were lower and follicle-stimulating hormone greater (P < 0.05) in the follicular and luteal phases, and the elevation in luteal-phase progesterone extended (P < 0.02). Thus, puberty onset was delayed and menstrual cycles prolonged and associated with altered serum hormone levels in baboon offspring that developed in an intrauterine environment in which estradiol levels were suppressed. Because puberty and follicle development, as shown previously, were normal in baboons treated in utero with letrozole and estradiol, we propose that fetal ovarian development and timely onset of puberty in the primate is programmed by fetal exposure to placental estrogen. PMID:24132960

  11. Animal models of human placentation--a review.

    PubMed

    Carter, A M

    2007-04-01

    This review examines the strengths and weaknesses of animal models of human placentation and pays particular attention to the mouse and non-human primates. Analogies can be drawn between mouse and human in placental cell types and genes controlling placental development. There are, however, substantive differences, including a different mode of implantation, a prominent yolk sac placenta, and fewer placental hormones in the mouse. Crucially, trophoblast invasion is very limited in the mouse and transformation of uterine arteries depends on maternal factors. The mouse also has a short gestation and delivers poorly developed young. Guinea pig is a good alternative rodent model and among the few species known to develop pregnancy toxaemia. The sheep is well established as a model in fetal physiology but is of limited value for placental research. The ovine placenta is epitheliochorial, there is no trophoblast invasion of uterine vessels, and the immunology of pregnancy may be quite different. We conclude that continued research on non-human primates is needed to clarify embryonic-endometrial interactions. The interstitial implantation of human is unusual, but the initial interaction between trophoblast and endometrium is similar in macaques and baboons, as is the subsequent lacunar stage. The absence of interstitial trophoblast cells in the monkey is an important difference from human placentation. However, there is a strong resemblance in the way spiral arteries are invaded and transformed in the macaque, baboon and human. Non-human primates are therefore important models for understanding the dysfunction that has been linked to pre-eclampsia and fetal growth restriction. Models that are likely to be established in the wake of comparative genomics include the marmoset, tree shrew, hedgehog tenrec and nine-banded armadillo.

  12. Interleukin-11 alters placentation and causes preeclampsia features in mice

    PubMed Central

    Winship, Amy L.; Koga, Kaori; Menkhorst, Ellen; Van Sinderen, Michelle; Rainczuk, Katarzyna; Nagai, Miwako; Cuman, Carly; Yap, Joanne; Zhang, Jian-Guo; Simmons, David; Young, Morag J.; Dimitriadis, Evdokia

    2015-01-01

    Preeclampsia (PE) is a pregnancy-specific disorder characterized by hypertension and proteinuria after 20 wk gestation. Abnormal extravillous trophoblast (EVT) invasion and remodeling of uterine spiral arterioles is thought to contribute to PE development. Interleukin-11 (IL11) impedes human EVT invasion in vitro and is elevated in PE decidua in women. We demonstrate that IL11 administered to mice causes development of PE features. Immunohistochemistry shows IL11 compromises trophoblast invasion, spiral artery remodeling, and placentation, leading to increased systolic blood pressure (SBP), proteinuria, and intrauterine growth restriction, although nonpregnant mice were unaffected. Real-time PCR array analysis identified pregnancy-associated plasma protein A2 (PAPPA2), associated with PE in women, as an IL11 regulated target. IL11 increased PAPPA2 serum and placental tissue levels in mice. In vitro, IL11 compromised primary human EVT invasion, whereas siRNA knockdown of PAPPA2 alleviated the effect. Genes regulating uterine natural killer (uNK) recruitment and differentiation were down-regulated and uNK cells were reduced after IL11 treatment in mice. IL11 withdrawal in mice at onset of PE features reduced SBP and proteinuria to control levels and alleviated placental labyrinth defects. In women, placental IL11 immunostaining levels increased in PE pregnancies and in serum collected from women before development of early-onset PE, shown by ELISA. These results indicate that elevated IL11 levels result in physiological changes at the maternal–fetal interface, contribute to abnormal placentation, and lead to the development of PE. Targeting placental IL11 may provide a new treatment option for PE. PMID:26655736

  13. Sex-Specific Placental Responses in Fetal Development

    PubMed Central

    2015-01-01

    The placenta is an ephemeral but critical organ for the survival of all eutherian mammals and marsupials. It is the primary messenger system between the mother and fetus, where communicational signals, nutrients, waste, gases, and extrinsic factors are exchanged. Although the placenta may buffer the fetus from various environmental insults, placental dysfunction might also contribute to detrimental developmental origins of adult health and disease effects. The placenta of one sex over the other might possess greater ability to respond and buffer against environmental insults. Given the potential role of the placenta in effecting the lifetime health of the offspring, it is not surprising that there has been a resurging interest in this organ, including the Human Placental Project launched by the National Institutes of Child Health and Human Development. In this review, we will compare embryological development of the laboratory mouse and human chorioallantoic placentae. Next, evidence that various species, including humans, exhibit normal sex-dependent structural and functional placental differences will be examined followed by how in utero environmental changes (nutritional state, stress, and exposure to environmental chemicals) might interact with fetal sex to affect this organ. Recent data also suggest that paternal state impacts placental function in a sex-dependent manner. The research to date linking placental maladaptive responses and later developmental origins of adult health and disease effects will be explored. Finally, we will focus on how sex chromosomes and epimutations may contribute to sex-dependent differences in placental function, the unanswered questions, and future directions that warrant further consideration. PMID:26241064

  14. HIV-1 Nef breaches placental barrier in rat model.

    PubMed

    Singh, Poonam; Agnihotri, Saurabh Kumar; Tewari, Mahesh Chandra; Kumar, Sadan; Sachdev, Monika; Tripathi, Raj Kamal

    2012-01-01

    The vertical transmission of HIV-1 from the mother to fetus is known, but the molecular mechanism regulating this transmission is not fully characterized. The fetus is highly protected by the placenta, which does not permit microbial pathogens to cross the placental barrier. In the present study, a rat model was established to observe the effect of HIV-1 protein Nef on placental barrier. Evans blue dye was used to assay permeability of placental barrier and fourteen day pregnant Sprague Dawley rats were injected intravenously with 2% Evans blue dye along with various concentrations of recombinant Nef. After an hour, animals were sacrificed and dye migration was observed through the assimilation of peripheral blood into fetus. Interestingly, traces of recombinant Nef protein were detected in the embryo as well as amniotic fluid and amniotic membrane along with placenta and uterus. Our study indicates that recombinant HIV-1-Nef protein breaches the placental barrier and allows the migration of Evans blue dye to the growing fetus. Further the concentration of Nef protein in blood is directly proportional to the intensity of dye migration and to the amount of Nef protein detected in uterus, placenta, amniotic membrane, amniotic fluid and embryo. Based on this study, it can be concluded that the HIV-1 Nef protein has a direct effect on breaching of the placental barrier in the model we have established in this study. Our observations will be helpful to understand the molecular mechanisms related to this breach of placental barrier by Nef in humans and may be helpful to identify specific Nef inhibitors.

  15. Mitochondrial cytochrome c oxidase deficiency.

    PubMed

    Rak, Malgorzata; Bénit, Paule; Chrétien, Dominique; Bouchereau, Juliette; Schiff, Manuel; El-Khoury, Riyad; Tzagoloff, Alexander; Rustin, Pierre

    2016-03-01

    As with other mitochondrial respiratory chain components, marked clinical and genetic heterogeneity is observed in patients with a cytochrome c oxidase deficiency. This constitutes a considerable diagnostic challenge and raises a number of puzzling questions. So far, pathological mutations have been reported in more than 30 genes, in both mitochondrial and nuclear DNA, affecting either structural subunits of the enzyme or proteins involved in its biogenesis. In this review, we discuss the possible causes of the discrepancy between the spectacular advances made in the identification of the molecular bases of cytochrome oxidase deficiency and the lack of any efficient treatment in diseases resulting from such deficiencies. This brings back many unsolved questions related to the frequent delay of clinical manifestation, variable course and severity, and tissue-involvement often associated with these diseases. In this context, we stress the importance of studying different models of these diseases, but also discuss the limitations encountered in most available disease models. In the future, with the possible exception of replacement therapy using genes, cells or organs, a better understanding of underlying mechanism(s) of these mitochondrial diseases is presumably required to develop efficient therapy.

  16. Mitochondrial Cytochrome c Oxidase Deficiency

    PubMed Central

    Rak, Malgorzata; Bénit, Paule; Chrétien, Dominique; Bouchereau, Juliette; Schiff, Manuel; El-Khoury, Riyad; Tzagoloff, Alexander; Rustin, Pierre

    2016-01-01

    As with other mitochondrial respiratory chain components, marked clinical and genetic heterogeneity is observed in patients with a cytochrome c oxidase deficiency. This constitutes a considerable diagnostic challenge and raises a number of puzzling questions. So far, pathological mutations have been reported in more than 30 genes, in both mitochondrial and nuclear DNA, affecting either structural subunits of the enzyme or proteins involved in its biogenesis. In this review, we discuss the possible causes of the discrepancy between the spectacular advances made in the identification of the molecular bases of cytochrome oxidase deficiency and the lack of any efficient treatment in diseases resulting from such deficiencies. This brings back many unsolved questions related to the frequent delay of clinical manifestation, variable course and severity, and tissue-involvement often associated with these diseases. In this context, we stress the importance to study different models of these diseases, but also discuss the limitations encountered in most available disease models. In the future, with the possible exception of replacement therapy using genes, cells or organs, a better understanding of underlying mechanism(s) of these mitochondrial diseases is presumably required to develop efficient therapy. PMID:26846578

  17. Placental mesenchymal dysplasia associated with hepatic and pulmonary hamartoma.

    PubMed

    Tortoledo, Maria; Galindo, A; Ibarrola, C

    2010-01-01

    This report describes a 31-week stillborn female infant with placental mesenchymal dysplasia (PMD) in association with hepatic mesenchymal hamartoma (HMH) and pulmonary hamartoma. Placental mesenchymal dysplasia was initially misdiagnosed as a partial mole. However, histologically, no trophoblastic proliferation or inclusions were observed. Differential diagnosis of the hepatic mass with similar tumors is discussed. To our knowledge, this is the first case of lung hamartoma reported in a fetus and the first case related to PMD and HMH. A common anomalous development of the mesoderm, a reparative post-injury process and a genetic mechanism, have been proposed to explain their pathogenesis.

  18. Infant sex-specific placental cadmium and DNA methylation associations

    SciTech Connect

    Mohanty, April F.; Farin, Fred M.; Bammler, Theo K.; MacDonald, James W.; Afsharinejad, Zahra; Burbacher, Thomas M.; Siscovick, David S.; and others

    2015-04-15

    Background: Recent evidence suggests that maternal cadmium (Cd) burden and fetal growth associations may vary by fetal sex. However, mechanisms contributing to these differences are unknown. Objectives: Among 24 maternal-infant pairs, we investigated infant sex-specific associations between placental Cd and placental genome-wide DNA methylation. Methods: We used ANOVA models to examine sex-stratified associations of placental Cd (dichotomized into high/low Cd using sex-specific Cd median cutoffs) with DNA methylation at each cytosine-phosphate-guanine site or region. Statistical significance was defined using a false discovery rate cutoff (<0.10). Results: Medians of placental Cd among females and males were 5 and 2 ng/g, respectively. Among females, three sites (near ADP-ribosylation factor-like 9 (ARL9), siah E3 ubiquitin protein ligase family member 3 (SIAH3), and heparin sulfate (glucosamine) 3-O-sulfotransferase 4 (HS3ST4) and one region on chromosome 7 (including carnitine O-octanoyltransferase (CROT) and TP5S target 1 (TP53TG1)) were hypomethylated in high Cd placentas. Among males, high placental Cd was associated with methylation of three sites, two (hypomethylated) near MDS1 and EVI1 complex locus (MECOM) and one (hypermethylated) near spalt-like transcription factor 1 (SALL1), and two regions (both hypomethylated, one on chromosome 3 including MECOM and another on chromosome 8 including rho guanine nucleotide exchange factor (GEF) 10 (ARHGEF10). Differentially methylated sites were at or close to transcription start sites of genes involved in cell damage response (SIAH3, HS3ST4, TP53TG1) in females and cell differentiation, angiogenesis and organ development (MECOM, SALL1) in males. Conclusions: Our preliminary study supports infant sex-specific placental Cd-DNA methylation associations, possibly accounting for previously reported differences in Cd-fetal growth associations across fetal sex. Larger studies are needed to replicate and extend these

  19. Sources for Comparative Studies of Placentation. II. Genomic Resources

    PubMed Central

    Wildman, Derek E.

    2008-01-01

    The genomes of dozens of placental mammal species are now publicly available. These genome sequences have the potential to provide insight into the development and evolution of the placenta. In particular, the variable anatomy of the placenta has likely been affected by natural selection on the genomes of living and extinct mammals. In this note the current availability of mammal genome sequences is reviewed, and strengths and limitations of these data are discussed. Additionally, museums, zoos, and commercial entities are available to provide genomic resources to the placental research community. Recommendations for tissue storage conditions of placentas in genomic research are given. PMID:18155141

  20. Placental histopathological changes associated with Plasmodium vivax infection during pregnancy.

    PubMed

    Souza, Rodrigo M; Ataíde, Ricardo; Dombrowski, Jamille G; Ippólito, Vanessa; Aitken, Elizabeth H; Valle, Suiane N; Álvarez, José M; Epiphanio, Sabrina; Epiphânio, Sabrina; Marinho, Claudio R F

    2013-01-01

    Histological evidence of Plasmodium in the placenta is indicative of placental malaria, a condition associated with severe outcomes for mother and child. Histological lesions found in placentas from Plasmodium-exposed women include syncytial knotting, syncytial rupture, thickening of the placental barrier, necrosis of villous tissue and intervillositis. These histological changes have been associated with P. falciparum infections, but little is known about the contribution of P. vivax to such changes. We conducted a cross-sectional study with pregnant women at delivery and assigned them to three groups according to their Plasmodium exposure during pregnancy: no Plasmodium exposure (n = 41), P. vivax exposure (n = 59) or P. falciparum exposure (n = 19). We evaluated their placentas for signs of Plasmodium and placental lesions using ten histological parameters: syncytial knotting, syncytial rupture, placental barrier thickness, villi necrosis, intervillous space area, intervillous leucocytes, intervillous mononucleates, intervillous polymorphonucleates, parasitized erythrocytes and hemozoin. Placentas from P. vivax-exposed women showed little evidence of Plasmodium or hemozoin but still exhibited more lesions than placentas from women not exposed to Plasmodium, especially when infections occurred twice or more during pregnancy. In the Brazilian state of Acre, where diagnosis and primary treatment are readily available and placental lesions occur in the absence of detected placental parasites, relying on the presence of Plasmodium in the placenta to evaluate Plasmodium-induced placental pathology is not feasible. Multivariate logistic analysis revealed that syncytial knotting (odds ratio [OR], 4.21, P = 0.045), placental barrier thickness (OR, 25.59, P = 0.021) and mononuclear cells (OR, 4.02, P = 0.046) were increased in placentas from P. vivax-exposed women when compared to women not exposed to Plasmodium during pregnancy. A vivax-score was

  1. Effects of incubation temperature and estrogen exposure on aromatase activity in the brain and gonads of embryonic alligators.

    PubMed Central

    Milnes, Matthew R; Roberts, Robert N; Guillette, Louis J

    2002-01-01

    During embryogenesis, incubation temperature and the hormonal environment influence gonadal differentiation of some reptiles, including all crocodilians. Current evidence suggests that aromatase, the enzyme that converts androgens to estrogens, has a role in sexual differentiation of species that exhibit temperature-dependent sex determination (TSD). During the temperature-sensitive period (TSP) of sex determination, we compared aromatase activity in the brain and gonads of putative male and female alligator embryos to determine if aromatase activity in the embryonic brain could provide the hormonal environment necessary for ovarian development in a TSD species. In addition, we assessed the pattern of aromatase activity in the brain and gonads of embryos treated with estradiol-17beta (E(2)) and incubated at male-producing temperatures to compare enzyme activity in E(2) sex-reversed females to control males and females. This has particular significance regarding wildlife species living in areas contaminated with suspected environmental estrogens. Gonadal aromatase activity remained low during the early stages of the TSP in both sexes and increased late in the TSP only in females. Aromatase activity in the brain increased prior to gonadal differentiation in both sexes. These results suggest that aromatase activity in the brain is not directly responsible for mediating differentiation of the gonad. E(2) exposure at male-producing temperatures resulted in sex-reversed females that had intermediate gonad function and masculinized brain activity. This study indicates the need to examine multiple end points and to determine the persistence of developmental alterations in contaminant-exposed wildlife populations. PMID:12060834

  2. IFPA Meeting 2011 workshop report I: Placenta: Predicting future health; roles of lipids in the growth and development of feto-placental unit; placental nutrient sensing; placental research to solve clinical problems--a translational approach.

    PubMed

    Acharya, G; Albrecht, C; Benton, S J; Cotechini, T; Dechend, R; Dilworth, M R; Duttaroy, A K; Grotmol, T; Heazell, A E; Jansson, T; Johnstone, E D; Jones, H N; Jones, R L; Lager, S; Laine, K; Nagirnaja, L; Nystad, M; Powell, T; Redman, C; Sadovsky, Y; Sibley, C; Troisi, R; Wadsack, C; Westwood, M; Lash, G E

    2012-02-01

    Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2011 there were twelve themed workshops, four of which are summarized in this report. These workshops related to both basic science and clinical research into placental growth and nutrient sensing and were divided into 1) placenta: predicting future health; 2) roles of lipids in the growth and development of feto-placental unit; 3) placental nutrient sensing; 4) placental research to solve clinical problems: a translational approach.

  3. Cytochrome c Negatively Regulates NLRP3 Inflammasomes

    PubMed Central

    Shi, Chong-Shan; Kehrl, John H.

    2016-01-01

    The release of cytochrome c from the inner mitochondrial membrane, where it is anchored by caridolipin, triggers the formation of the Apaf-1 apoptosome. Cardiolipin also interacts with NLRP3 recruiting NLRP3 to mitochondria and facilitating inflammasome assembly. In this study we investigated whether cytosolic cytochrome c impacts NLRP3 inflammasome activation in macrophages. We report that cytochrome c binds to the LRR domain of NLRP3 and that cytochrome c reduces the interactions between NLRP3 and cardiolipin and between NLRP3 and NEK7, a recently recognized component of the NLRP3 inflammasome needed for NLRP3 oligomerization. Protein transduction of cytochrome c impairs NLRP3 inflammasome activation, while partially silencing cytochrome c expression enhances it. The addition of cytochrome c to an in vitro inflammasome assay severely limited caspase-1 activation. We propose that there is a crosstalk between the NLRP3 inflammasome and apoptosome pathways mediated by cytochrome c, whose release during apoptosis acts to limit NLRP3 inflammasome activation. PMID:28030552

  4. BENZO(A)PYRENE DECREASES BRAIN AND OVARIAN AROMATASE mRNA EXPRESSION IN FUNDULUS HETEROCLITUS

    PubMed Central

    Dong, Wu; Wang, Lu; Thornton, Cammi; Scheffler, Brian E.; Willett, Kristine L.

    2008-01-01

    The higher molecular weight polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (BaP) are typically associated with genotoxicity, however, newer evidence suggests that these compounds may also act as endocrine system disruptors. We hypothesized that altered expression of the P450 enzyme aromatase genes could be a target for reproductive or developmental dysfunction caused by BaP exposure. Aromatase is at least partially responsible for estrogen homeostasis by converting androgens into estrogens. In fish, there are two isoforms of aromatase, a predominantly ovarian form, CYP19A1, and a brain form, CYP19A2. CYP19 mRNA expression was measured following BaP exposure (0, 10, 100 µg/L waterborne for 10 or 15 days) in Fundulus adults, juveniles and embryos by in situ hybridization. The CYP19A1 expression was significantly decreased after BaP exposure in the 3 month old Fundulus immature oocytes, but BaP did not affect CYP19A1 expression at any stage in adult oocytes. In embryo brains, BaP significantly decreased CYP19A2 compared to controls by 3.6-fold at 14 days post-fertilization. In adults, CYP19A2 expression was decreased significantly in the pituitary and hypothalamus (81% and 85% of controls, respectively). Promoter regions of Fundulus CYP19s were cloned, and putative response elements in the CYP19A1 and CYP19A2 promoters such as CRE, AhR and ERE may be involved in BaP-mediated changes in CYP19 expression. In order to compare the mechanism of BaP-mediated inhibition with that of a known aromatase inhibitor, fish were also exposed to fadrozole (20 and 100 µg/L). Fadrozole did not significantly decrease the mRNA expression in embryos or adult Fundulus. However, aromatase enzyme activity was significantly decreased in adult ovary and brain tissues. These studies provide a greater molecular understanding of the mechanisms of action of BaP and its potential to impact reproduction or development. PMID:18571745

  5. Placental Hypoxia During Early Pregnancy Causes Maternal Hypertension and Placental Insufficiency in the Hypoxic Guinea Pig Model.

    PubMed

    Thompson, Loren P; Pence, Laramie; Pinkas, Gerald; Song, Hong; Telugu, Bhanu P

    2016-12-01

    Chronic placental hypoxia is one of the root causes of placental insufficiencies that result in pre-eclampsia and maternal hypertension. Chronic hypoxia causes disruption of trophoblast (TB) development, invasion into maternal decidua, and remodeling of maternal spiral arteries. The pregnant guinea pig shares several characteristics with humans such as hemomonochorial placenta, villous subplacenta, deep TB invasion, and remodeling of maternal arteries, and is an ideal animal model to study placental development. We hypothesized that chronic placental hypoxia of the pregnant guinea pig inhibits TB invasion and alters spiral artery remodeling. Time-mated pregnant guinea pigs were exposed to either normoxia (NMX) or three levels of hypoxia (HPX: 16%, 12%, or 10.5% O2) from 20 day gestation until midterm (39-40 days) or term (60-65 days). At term, HPX (10.5% O2) increased maternal arterial blood pressure (HPX 57.9 ± 2.3 vs. NMX 40.4 ± 2.3, P < 0.001), decreased fetal weight by 16.1% (P < 0.05), and increased both absolute and relative placenta weights by 10.1% and 31.8%, respectively (P < 0.05). At midterm, there was a significant increase in TB proliferation in HPX placentas as confirmed by increased PCNA and KRT7 staining and elevated ESX1 (TB marker) gene expression (P < 0.05). Additionally, quantitative image analysis revealed decreased invasion of maternal blood vessels by TB cells. In summary, this animal model of placental HPX identifies several aspects of abnormal placental development, including increased TB proliferation and decreased migration and invasion of TBs into the spiral arteries, the consequences of which are associated with maternal hypertension and fetal growth restriction.

  6. IFPA Meeting 2012 Workshop Report I: comparative placentation and animal models, advanced techniques in placental histopathology, human pluripotent stem cells as a model for trophoblast differentiation.

    PubMed

    Ackerman, W E; Carter, A M; De Mestre, A M; Golos, T G; Jeschke, U; Kusakabe, K; Laurent, L C; Parast, M M; Roberts, R M; Robinson, J M; Rutherford, J; Soma, H; Takizawa, T; Ui-Tei, K; Lash, G E

    2013-03-01

    Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2012 there were twelve themed workshops, three of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of models and technical issues involved in placenta research: 1) comparative placentation and animal models; 2) advanced techniques in placental histopathology; 3) human pluripotent stem cells as a model for trophoblast differentiation.

  7. Cytochrome b5 Expression in Gonadectomy-induced Adrenocortical Neoplasms of the Domestic Ferret (Mustela putorius furo)

    PubMed Central

    Wagner, S.; Kiupel, M.; Peterson, R.A.; Heikinheimo, M.; Wilson, D.B.

    2008-01-01

    Whereas the adrenal glands of healthy ferrets produce only limited amounts of androgenic steroids, adrenocortical neoplasms that arise in neutered ferrets typically secrete androgens or their derivative, estrogen. The 17,20-lyase activity of cytochrome P450 17α-hydroxylase/17,20-lyase (P450c17) must increase to permit androgen biosynthesis in neoplastic adrenal tissue. We screened ferret adrenocortical tumor specimens for expression of cytochrome b5 (cyt b5), an allosteric regulator that selectively enhances the 17,20-lyase activity of P450c17. Cyt b5 immunoreactivity was evident in 24 of 25 (96 %) adrenocortical adenomas/carcinomas from ferrets with signs of ectopic sex steroid production. Normal adrenocortical cells lacked cyt b5, which may account for the low production of adrenal androgens in healthy ferrets. Other markers characteristic of gonadal somatic cells, such as luteinizing hormone receptor, aromatase, and GATA4, were co-expressed with cyt b5 in some of the tumors. We conclude that cyt b5 is upregulated during gonadectomy-induced adrenocortical neoplasia and is a marker of androgen synthetic potential in these tumors. PMID:18587089

  8. Dietary polyphenols suppress elevated levels of proinflammatory mediators and aromatase in the mammary gland of obese mice.

    PubMed

    Subbaramaiah, Kotha; Sue, Erika; Bhardwaj, Priya; Du, Baoheng; Hudis, Clifford A; Giri, Dilip; Kopelovich, Levy; Zhou, Xi Kathy; Dannenberg, Andrew J

    2013-09-01

    In postmenopausal women, obesity is a risk factor for the development of hormone receptor-positive breast cancer driven by estrogen. After menopause, aromatization of androgen precursors in adipose tissue is a major synthetic source of estrogen. Recently, in mouse models and women, we identified an obesity-inflammation-aromatase axis. This obesity-induced inflammation is characterized by crown-like structures (CLS) consisting of dead adipocytes encircled by macrophages in breast white adipose tissue. CLS occur in association with NF-κB activation, elevated levels of proinflammatory mediators, and increased aromatase expression. Saturated fatty acids released from adipocytes have been linked to obesity-related white adipose tissue inflammation. Here we found that stearic acid, a prototypic saturated fatty acid, stimulated Akt-dependent activation of NF-κB resulting in increased levels of proinflammatory mediators [TNF-α, interleukin (IL)-1β, COX-2] in macrophages leading, in turn, to the induction of aromatase. Several polyphenols (resveratrol, curcumin, epigallocatechin gallate) blocked these inductive effects of stearic acid. Zyflamend, a widely used polyherbal preparation that contains numerous polyphenols, possessed similar suppressive effects. In a mouse model of obesity, treatment with Zyflamend suppressed levels of phospho-Akt, NF-κB binding activity, proinflammatory mediators, and aromatase in the mammary gland. Collectively, these results suggest that targeting the activation of NF-κB is a promising approach for reducing levels of proinflammatory mediators and aromatase in inflamed mouse mammary tissue. Further investigation in obese women is warranted.

  9. Differential expression of mRNA aromatase in ejaculated spermatozoa from infertile men in relation to either asthenozoospermia or teratozoospermia.

    PubMed

    Said, L; Saad, A; Carreau, S

    2014-03-01

    Oestrogen biosynthesis in ejaculated spermatozoa is an autonomous process, which may influence sperm functions. The purpose of this study was to evaluate the relationship between the expression of aromatase, sperm quality and seminal neutral α-glucosidase marker in semen of Tunisian infertile men: asthenozoospermia (A; n = 16), teratozoospermia (T; n = 12) and asthenoteratozoospermia (AT; n = 11) in comparison with 18 normozoospermic ones. Aromatase mRNA levels estimated by real-time PCR were reduced in groups T (52%) and AT (67%) compared to controls and inversely correlated with the percentage of normal forms. A higher coefficient of correlation was noted in presence of microcephaly or acrosome malformations (r = -0.64). The asthenozoospermic group was divided into two subgroups according to the relative amount of aromatase. The subgroup (A2) with higher aromatase transcript level was associated with an increased seminal pH, a decreased sperm viability, low sperm percentage motility and low neutral α-glucosidase semen levels. Our data highlight the involvement of aromatase in motility and morphology of spermatozoa. Thus, this enzyme could bring new insights about quality and fertilising capacity of human spermatozoa.

  10. Notch signalling in placental development and gestational diseases.

    PubMed

    Haider, S; Pollheimer, J; Knöfler, M

    2017-01-16

    Activation of Notch signalling upon cell-cell contact of neighbouring cells controls a plethora of cellular processes such as stem cell maintenance, cell lineage determination, cell proliferation, and survival. Accumulating evidence suggests that the pathway also critically regulates these events during placental development and differentiation. Herein, we summarize our present knowledge about Notch signalling in murine and human placentation and discuss its potential role in the pathophysiology of gestational disorders. Studies in mice suggest that Notch controls trophectoderm formation, decidualization, placental branching morphogenesis and endovascular trophoblast invasion. In humans, the particular signalling cascade promotes formation of the extravillous trophoblast lineage and regulates trophoblast proliferation, survival and differentiation. Expression patterns as well as functional analyses indicate distinct roles of Notch receptors in different trophoblast subtypes. Altered effects of Notch signalling have been detected in choriocarcinoma cells, consistent with its role in cancer development and progression. Moreover, deregulation of Notch signalling components were observed in pregnancy disorders such as preeclampsia and fetal growth restriction. In summary, Notch plays fundamental roles in different developmental processes of the placenta. Abnormal signalling through this pathway could contribute to the pathogenesis of gestational diseases with aberrant placentation and trophoblast function.

  11. Placental Development in a Mouse Model of Spinal Muscular Atrophy

    PubMed Central

    Van Granigen Caesar, Gerialisa; Dale, Jeffrey M.; Osman, Erkan Y.; Garcia, Michael L.; Lorson, Christian L.; Schulz, Laura C.

    2016-01-01

    Spinal Muscular Atrophy (SMA) is an autosomal recessive disorder, leading to fatal loss of motor neurons. It is caused by loss of function of the SMN gene, which is expressed throughout the body, and there is increasing evidence of dysfunction in non-neuronal tissues. Birthweight is one of most powerful prognostic factors for infants born with SMA, and intrauterine growth restriction is common. In the SMNΔ7 mouse model of SMA, pups with the disease lived 25% longer when their mothers were fed a higher fat, “breeder” diet. The placenta is responsible for transport of nutrients from mother to fetus, and is a major determinant of fetal growth. Thus, the present study tested the hypothesis that placental development is impaired in SMNΔ7 conceptuses. Detailed morphological characterization revealed no defects in SMNΔ7 placental development, and expression of key transcription factors regulating mouse placental development was unaffected. The intrauterine growth restriction observed in SMA infants likely does not result from impaired placental development. PMID:26748185

  12. Development and regulation of placental androstenedione during rat pregnancy

    SciTech Connect

    Jackson, J.A.

    1986-01-01

    The present study determined the ability of the rat placenta to convert (/sup 3/H) pregnenolone (P/sub 5/) substrate to (/sup 3/H)..delta../sup 4/A and (/sup 3/H)T and to the intermediate steroid (/sup 3/H)P/sub 4/ in vitro on days 12 to 18 of gestation. Placental androgen formation increased and the amount of P/sub 4/ formed and not further metabolized to ..delta../sup 4/A decreased during gestation, with the formation of ..delta../sup 4/A 2- to 4-fold greater (p<0.01) than the formation of T. Moreover, the ovarian conversion of (/sup 3/H)..delta../sup 4/A to (/sup 3/H)E/sub 2/ was 2- to 4-fold greater (p<0.05) than the conversion from (/sup 3/H)T. To determine if the ovary, specifically estrogen, regulates placental ..delta../sup 4/A production, rats were ovariectomized (OVX) on day 9 of gestation and given a Silastic capsule containing either E/sub 2/ or vehicle. On day 14 OVX animals had an increased (p <0.01) ability to form placental ..delta../sup 4/A and decreased (p <0.05) ability to form P/sub 4/. The formation of placental ..delta../sup 4/A invitro was correlated with elevated peripheral serum ..delta../sup 4/A concentrations in OVX animals, an effect which was reversed by E/sub 2/.

  13. Polyaromatic compounds alter placental protein synthesis in pregnant rats

    SciTech Connect

    Shiverick, K.T.; Ogilvie, S.; Medrano, T. )

    1991-03-15

    The administration of the polyaromatic compounds {beta}-naphthoflavone ({beta}NF) and 3-methylcholanthrene (3MC) to pregnant rats during mid-gestation has been shown to produce marked feto-placental growth retardation. This study examined secretory protein synthesis in placental tissue from rats following administration of {beta}NF on gestation days (gd) 11-14 or 3MC on gd 12-14. Explants of placental basal zone tissue were cultured for 24 hours in serum-free medium in the presence of ({sup 3}H)leucine. Secreted proteins were analyzed by two-dimensional SDS-polyacrylamide gel electrophoresis followed by either fluorography or immunostaining. Total incorporation of ({sup 3}H)leucine into secreted proteins was not altered in BZ explants from {beta}NF or 3MC-treated animals. However a selective decrease was observed in ({sup 3}H)leucine incorporation into a major complex of proteins with apparent molecular weight of 25-30,000 and isoelectric point between 5.3 to 5.7. This group of proteins has been further identified as being related to rat pituitary growth hormone (GH) using N-terminal amino acid microsequencing of individual spots from 2-D SDS-PA gels. This is the first report that synthesis of GH-related proteins by rat placenta is decreased following {beta}NF and 3MC administration, a change which may underlie the feto-placental growth retardation associated with these polyaromatic compounds.

  14. Maternal obesity is associated with a lipotoxic placental environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maternal obesity is associated with placental lipotoxicity, oxidative stress, and inflammation, where MAPK activity may pl