Molecular cloning of estrogen receptor and its function on vitellogenesis in pompano (Trachinotus ovatus).

Estrogen receptors (ERs) play a critical role in vitellogenesis (Vtgs). However, the contribution of each ER for the regulation of vtgs expression was not analyzed clearly in teleosts. In the present study, three ers isoforms (erα, erß1, and erß2) were cloned in pompano (Trachinotus ovatus). Real-time PCR and enzyme-linked immunosorbent assay (ELISA) was used to detect the effects of 17ß-estradiol (E2) on ERs and Vtgs in the liver of pompano. In vivo injection experiments showed that E2 significantly increased the expressions of ers and vtgs. ER broad spectrum antagonist Fulvestrant significantly attenuated the E2- induced up-regulation of ers and vtgs in a dose-dependent manner. ERα antagonist Methyl-piperidino pyrazole (MPP) significantly attenuated the up-regulation of erα, erß2, vtg-B and vtg-C, and promoted the expressions of erß1 and vtg-A. ERß antagonist Cyclofenil significantly inhibited the expressions of erß1, erß2, vtg-A and vtg-C, and promoted the expressions of erα and vtg-B. In addition, E2 significantly increased the protein level of Vtg, while Fulvestrant, MPP and Cyclofenil significantly inhibited the protein level of Vtg in a dose-dependent manner. Our results indicate that E2 may regulate the expression of each vtg with different subtypes of ERs, and shows a distinct compensatory expression effect on the regulation for ers and vtgs, which provides a theoretical basis for reproductive endocrinology study in pompano.

An estrogen antagonist, cyclofenil, has anti-dengue-virus activity.

Dengue virus (DENV) infections are a major cause of morbidity and mortality in tropical and subtropical areas. Several compounds that act against DENV have been studied in clinical trials to date; however, there have been no compounds identified that are effective in reducing the severity of the clinical manifestations. To explore anti-DENV drugs, we examined small molecules that interact with DENV NS1 and inhibit DENV replication. Cyclofenil, which is a selective estrogen receptor modulator (SERM) and has been used clinically as an ovulation-inducing drug, showed an inhibitory effect on DENV replication in mammalian cells but not in mosquito cells. Other SERMs also inhibited DENV replication in mammalian cells, but cyclofenil showed the weakest cytotoxicity among these SERMs. Cyclofenil also inhibited the replication of Zika virus. A time-of-addition assay suggested that cyclofenil may interfere with two stages of the DENV life cycle: the translation-RNA synthesis and assembly-maturation stages. However, the level of intracellular infectious particles decreased more drastically after treatment with cyclofenil than the viral RNA level did, indicating that the assembly-maturation stage might be the main target of cyclofenil. In electron microscopy analysis, many aggregated particles were detected in DENV-infected cells in the presence of cyclofenil, supporting the possibility that cyclofenil impedes the process of assembly and maturation of DENV.

Structure-activity relationship study of estrogen receptor down-regulators with a diphenylmethane skeleton.

Selective estrogen receptor (ER) down-regulators (SERDs) are pure ER antagonists that also induce ER degradation upon binding to the receptor. Although SERDs have been developed for the treatment of ER-positive breast cancers for nearly a decade, their precise mechanism(s) of action and structure-activity relationship are still unclear. Generally, Western blotting is used to examine the effects of SERDs on ER protein levels, but the methodology is low-throughput and not quantitative. Here, we describe a quantitative, high-throughput, luciferase-based assay for the evaluation of SERDs activity. For this purpose, we established stable recombinant HEK-293 cell lines expressing ERα fused with emerald luciferase. We also designed and synthesized new diphenylmethane derivatives as candidate SERDs, and evaluated their SERDs activity using the developed system in order to examine their structure-activity relationship, taking EC50 as a measure of potency, and Emax as a measure of efficacy.

Novel Selective Estrogen Receptor Ligand Conjugates Incorporating Endoxifen-Combretastatin and Cyclofenil-Combretastatin Hybrid Scaffolds: Synthesis and Biochemical Evaluation.

Nuclear receptors such as the estrogen receptors (ERα and ERß) modulate the effects of the estrogen hormones and are important targets for design of innovative chemotherapeutic agents for diseases such as breast cancer and osteoporosis. Conjugate and bifunctional compounds which incorporate an ER ligand offer a useful method of delivering cytotoxic drugs to tissue sites such as breast cancers which express ERs. A series of novel conjugate molecules incorporating both the ER ligands endoxifen and cyclofenil-endoxifen hybrids covalently linked to the antimitotic and tubulin targeting agent combretastatin A-4 were synthesised and evaluated as ER ligands. A number of these compounds demonstrated pro-apoptotic effects, with potent antiproliferative activity in ER-positive MCF-7 breast cancer cell lines and low cytotoxicity. These conjugates displayed binding affinity towards ERα and ERß isoforms at nanomolar concentrations e.g., the cyclofenil-amide compound 13e is a promising lead compound of a clinically relevant ER conjugate with IC50 in MCF-7 cells of 187 nM, and binding affinity to ERα (IC50 = 19 nM) and ERß (IC50 = 229 nM) while the endoxifen conjugate 16b demonstrates antiproliferative activity in MCF-7 cells (IC50 = 5.7 nM) and binding affinity to ERα (IC50 = 15 nM) and ERß (IC50 = 115 nM). The ER binding effects are rationalised in a molecular modelling study in which the disruption of the ER helix-12 in the presence of compounds 11e, 13e and 16b is presented These conjugate compounds have potential application for further development as antineoplastic agents in the treatment of ER positive breast cancers.

Effects of platelet-activating factor and its differential regulation by androgens and steroid hormones in prostate cancers.

BACKGROUND: Platelet-activating factor (PAF) is an arachidonic acid metabolite that plays an important role in cell proliferation, migration and neoangiogenesis, but whether it is involved in the progression of prostate cancer remains undiscovered. METHODS: Clinical prostate specimens were investigated with immunohistochemistry method and in vitro cell experiments referred to MTS cell proliferation assay, invasion and migration experiment, quantitative real-time RT-PCR assay, western blotting analysis and ELISA assay. RESULTS: Platelet-activating factor synthetase, lyso-PAF acetyl transferase (LPCAT1), increased significantly in castration-resistant prostate cancer (CRPC) specimens and CRPC PC-3 cells than that in controls. Intriguingly, PAF induced invasion and migration of PC-3 cells but not LNCaP cells. The PAF receptor antagonist inhibited proliferation of LNCaP and PC-3 cells. Dihydrotestosterone (DHT) treatment caused a decrease in LPCAT1 expression and PAF release in LNCaP cells, which could be blocked by androgen receptor antagonists. Finally, DHT increased LPCAT1 expression and PAF release in PC-3 cells in a Wnt/ß-catenin-dependent manner. CONCLUSION: For the first time, our data supported that PAF might play pivotal roles in the progression of prostate cancer, which might throw a new light on the treatment of prostate cancer and the prevention of the emergence of CRPC.

Monitoring a coordinated exchange process in a four-component biological interaction system: development of a time-resolved terbium-based one-donor/three-acceptor multicolor FRET system.

Hormonal regulation of cellular function involves the binding of small molecules with receptors that then coordinate subsequent interactions with other signal transduction proteins. These dynamic, multicomponent processes are difficult to track in cells and even in reconstituted in vitro systems, and most methods can monitor only two-component interactions, often with limited capacity to follow dynamic changes. Through a judicious choice of three organic acceptor fluorophores paired with a terbium donor fluorophore, we have developed the first example of a one-donor/three-acceptor multicolor time-resolved fluorescence energy transfer (TR-FRET) system, and we have exemplified its use by monitoring a ligand-regulated protein-protein exchange process in a four-component biological system. By careful quantification of the emission from each of the three acceptors at the four channels for terbium donor emission, we demonstrate that any of these donor channels can be used to estimate the magnitude of the three FRET signals in this terbium-donor triple-acceptor system with minimal bleedthrough. Using this three-channel terbium-based, TR-FRET assay system, we show in one experiment that the addition of a fluorescein-labeled estrogen agonist displaces a SNAPFL-labeled antiestrogen from the ligand binding pocket of a terbium-labeled estrogen receptor, at the same time causing a Cy5-labeled coactivator to be recruited to the estrogen receptor. This experiment demonstrates the power of a four-color TR-FRET experiment, and it shows that the overall process of estrogen receptor ligand exchange and coactivator binding is a dynamic but precisely coordinated process.

Photocontrol of protein activity in cultured cells and zebrafish with one- and two-photon illumination.

We have implemented a noninvasive optical method for the fast control of protein activity in a live zebrafish embryo. It relies on releasing a protein fused to a modified estrogen receptor ligand binding domain from its complex with cytoplasmic chaperones, upon the local photoactivation of a nonendogenous caged inducer. Molecular dynamics simulations were used to design cyclofen-OH, a photochemically stable inducer of the receptor specific for 4-hydroxy-tamoxifen (ER(T2)). Cyclofen-OH was easily synthesized in two steps with good yields. At submicromolar concentrations, it activates proteins fused to the ER(T2) receptor. This was shown in cultured cells and in zebrafish embryos through emission properties and subcellular localization of properly engineered fluorescent proteins. Cyclofen-OH was successfully caged with various photolabile protecting groups. One particular caged compound was efficient in photoinducing the nuclear translocation of fluorescent proteins either globally (with 365 nm UV illumination) or locally (with a focused UV laser or with two-photon illumination at 750 nm). The present method for photocontrol of protein activity could be used more generally to investigate important physiological processes (e.g., in embryogenesis, organ regeneration and carcinogenesis) with high spatiotemporal resolution.

Design, synthesis, and evaluation of cyclofenil derivatives for potential SPECT imaging agents.

To develop technetium- and rhenium-labeled nonsteroidal estrogen imaging agents for estrogen receptor (ER) positive breast tumors, two groups of rhenium and technetium cyclofenil derivatives were synthesized and characterized. The binding affinities of the rhenium complexes for ERs were determined. The tricarbonyl rhenium complex showed the highest binding affinity for ERs (81.2 for ERbeta, 16.5 for ERalpha). Tricarbonyl technetium cyclofenil complexes were obtained in high radiochemical purity and radiochemical yields. The results of studies of their octanol/water partition and in vitro stability are presented. These results demonstrate that these radiolabeled cyclofenil derivatives may be considered as potential breast cancer imaging agents.

Development of bivalent triarylalkene- and cyclofenil-derived dual estrogen receptor antagonists and downregulators.

Up to 80% of mammary carcinoma initially exhibit estrogen-dependent growth, which can be treated by aromatase inhibitors or SERMs/SERDs. To increase the options after failure of the hormonal therapy with these drugs, the search for alternatives with a different mode of action to prevent estrogen action is of high relevance. Therefore, this study focused on the inhibition of coactivator recruitment at the estrogen receptor (ER) by targeted attachment of bivalent compounds at the coactivator binding site besides the primary binding at the ligand binding domain. Eight homodimeric 4-[1-(4-hydroxyphenyl)-2-phenyl-1-butenyl]cinnamic acid (GW7604)- or cyclofenilacrylic acid-based ER ligands with diaminoalkane linkers (C2-C5) were synthesized and their effects on the ER subtypes were assessed in vitro. All compounds possessed full antagonistic potency at ERα/ß as determined in a transactivation assay. Furthermore, they exerted medium downregulatory effects dependent on the spacer length and did not stimulate the ER expression as observed for 4-hydroxytamoxifen. The cyclofenil-derived dimer with C4 spacer (15b) showed the highest binding affinity to ERα (RBA = 79.2%) and downregulated the ER content in MCF-7 cells with an efficiency of 38% at 1 µM.

Synthesis and identification of hydroxylated metabolites of the anti-estrogenic agent cyclofenil.

The detection of metabolites of the anti-estrogenic substance cyclofenil, listed on the World Anti-Doping Agency (WADA) Prohibited List since 2004 is described. Target substances are hydroxylated metabolites, bearing an aliphatic hydroxyl group either in the 2-, 3- or 4-position of the aliphatic ring, in addition to the phenolic functions on the aromatic rings. Structural identification used NMR as well as high-resolution mass spectrometry after nano-electrospray ionisation (ESI). Unambiguous detection of all three synthesised cyclofenil metabolites M1-M3 was done using gas chromatography for separation and electron ionisation mass spectrometry for detection of the per-silylated compounds in comparison with a reference urine deriving from an excretion study within the WADA 2007 Educational Programme.

Synthesis of new carbon-11 labeled cyclofenil derivatives for PET imaging of breast cancer estrogen receptors.

Carbon-11 labeled cyclofenil derivatives, [(11)C]methyl-2-{4-[bis(4-hydroxyphenyl)methylene]cyclohexyl}acetate ([(11)C]16a), [(11)C]methyl-4-[bis(4-hydroxyphenyl)methylene]cyclohexanecarboxylate ([(11)C]16b), [(11)C]methyl-2-{3-[bis(4-hydroxyphenyl)methylene]cyclohexyl}acetate ([(11)C]18a), and [(11)C]methyl-3-[bis(4-hydroxyphenyl)methylene]cyclohexanecarboxylate ([(11)C]18b), have been synthesized as new potential PET agents for imaging breast cancer estrogen receptors. The target tracers were prepared by O-[(11)C]methylation of their corresponding precursors using [(11)C]CH(3)OTf and isolated by a simplified SPE purification procedure in 35-50% radiochemical yields decay corrected to EOB, 15-20 min overall synthesis time, and 74-111 GBq/micromol specific activity at EOS.

Synthesis and biodistribution of fluorine-18-labeled fluorocyclofenils for imaging the estrogen receptor.

C4-[18F]Fluorocyclofenil ([18F]FCF, 6) and C3-[18F]fluoroethylcyclofenil ([18F]FECF, 9), two high-affinity nonsteroidal estrogens, were prepared and investigated as potential agents for imaging estrogen receptors (ERs) in breast tumors. Both of these compounds could be prepared conveniently from alkyl methanesulfonate precursors (5,8) by fluoride displacement reactions, and they were obtained in high radiochemical purity and radiochemical yields, with effective specific activities sufficient for in vivo biodistribution studies. While the biodistribution of [18F]FCF (6) in immature female rats showed no selective target tissue uptake, the biodistribution of [18F]FECF (9) showed selective uptake by the uterus, but this uptake could not be blocked by excess estradiol. The poor in vivo biodistribution of these otherwise high-affinity ligands arouses curiosity, and together with recent results on the biodistribution of other nonsteroidal ligands suggests that factors other than receptor binding affinity are important for in vivo imaging of estrogen target tissues and ER-positive breast tumors.

Fluorine-substituted cyclofenil derivatives as estrogen receptor ligands: synthesis and structure-affinity relationship study of potential positron emission tomography agents for imaging estrogen receptors in breast cancer.

In a search for estrogen receptor (ER) ligands to be radiolabeled with fluorine-18 for imaging of ER-positive breast tumors with positron emission tomography (PET), we investigated cyclofenil analogues substituted at the C3 or C4 position of the cyclohexyl group. McMurry coupling of 4,4'-dihydroxybenzophenone with various ketones produced key cyclofenil intermediates, from which C3 and C4 substituents containing alkyl and various oxygen or fluorine-substituted alkyl groups were elaborated. Binding assays to both ERalpha and ERbeta revealed that the C3 site is more tolerant of steric bulk and polar groups than the C4 site, consistent with a computational model of the ERalpha ligand binding pocket. Fluorine substitution is tolerated very well at some sites, giving some compounds having affinities comparable to or higher than that of estradiol. These fluoro and fluoroalkyl cyclofenils merit further consideration as fluorine-18 labeled ER ligands for PET imaging of ERs in breast tumors.

Catechol estrogens of the 1,1,2-triphenylbut-1-ene type: relationship between structure, estradiol receptor affinity, estrogenic and antiestrogenic properties, and mammary tumor inhibiting activities.

1,1,2-Triphenylbut-1-enes (26-35), which are substituted with one or two 3,4-diacetoxy groups or with one 3,4-diacetoxy and one 3- or 4-acetoxy group in two aromatic rings, were synthesized. The occurring E and Z isomers were isolated, and their identity was established by 1H NMR spectroscopy. A study on structure-activity relationship was carried out with regard to estradiol receptor affinity in vitro, estrogenic and antiestrogenic properties in the immature mouse, and inhibition of the hormone-dependent MXT mammary tumor of the mouse in vivo. Among the tested compounds, most of the 1,1-disubstituted 1,1,2-triphenylbut-1-enes (29, Z-30, Z,E-31) and (E)-1-(3-acetoxyphenyl)-1-phenyl-2-(3,4-diacetoxyphenyl)but- 1-ene (E-35) as well as its respective Z isomer (Z-35) exerted antiestrogenic properties. Compounds Z-30, Z,E-31, Z-35, and E-35 inhibited the growth of the hormone-dependent MXT tumor. The best antitumor effect without estrogenic side effects during therapy was shown by E-35.

Ovarian activity, and total gonadotrophin and gonadotrophin releasing hormone levels in response to some synthetic non-steroidal ovulating agents in the catfish, Heteropneustes fossilis (Bloch).

Effects of clomiphene citrate, cyclofenil and prostaglandins (PGE1 and PGF2 alpha) on ovarian 32P uptake, on gonadotrophin levels in the pituitary gland and blood serum and on a gonadotrophin releasing hormone-like (GnRH-like) substance in the hypothalamus were investigated in Heteropneustes fossilis. These drugs were very effective in increasing the serum level of gonadotrophin with a subsequent increase in ovarian 32P uptake in sham-hypophysectomized recipients. All the drugs except cyclofenil failed to stimulate 32P incorporation by the ovary in hypophysectomized fish. Clomiphene citrate and cyclofenil also induced a significant increase in the GnRH-like factor in the hypothalamus of H. fossilis. Such a response was not obtained in fish treated with PGE1 and PGF2 alpha. It seems likely that the action of clomiphene is routed through the hypothalamo-pituitary-ovarian axis and that of prostaglandins directly through the pituitary-ovarian axis. The action of cyclofenil is bimodal; one effect like that of clomiphene and the other direct upon the ovary probably by increasing its sensitivity to the available gonadotrophin.

The effects of clomiphene citrate and cyclofenil on cervical mucus volume and receptivity over the periovulatory period.

OBJECTIVE: To determine the effects of clomiphene citrate (CC) and cyclofenil on cervical mucus (CM) volume and receptivity sampled serially over the periovulatory period. DESIGN: Using prospective luteinizing hormone (LH) timing CM volume and receptivity were compared in standard CC and cyclofenil-stimulated cycles using normal ovulatory cycles as controls. LOCATION: The Donor Insemination Unit at the University Research Clinic, Sheffield, United Kingdom. PATIENTS: Twenty anovulatory patients and 10 normally ovulating patients, all of whom were participating in a treatment cycle of donor insemination. INTERVENTIONS: The 20 anovulatory patients were allocated at random into two groups: group 1 was administered 50 mg of CC on days 2 to 6 of the menstrual cycle; group 2 was administered 400 mg of cyclofenil on days 3 to 12 of the menstrual cycle. All the patients were given a single treatment of donor insemination 24 to 36 hours after the onset of the LH surge. RESULTS: Clomiphene citrate and cyclofenil were shown to exert differential impacts on CM quantity and quality. In terms of quantity, the CC patients produced significantly lower volumes of CM than the cyclofenil patients and controls. In terms of quality, the CC patients and controls produced CM of similar receptivity, whereas the cyclofenil patients produced CM that was significantly more receptive to sperm than both the CC patients and controls. CONCLUSIONS: Neither CC nor cyclofenil exerted a detrimental impact on CM quality throughout the periovulatory period.

Cyclofenil for Raynaud's phenomenon in progressive systemic sclerosis.

OBJECTIVES: To assess the effects and toxicity of Cyclofenil versus placebo for the treatment of Raynaud's phenomenon (RP) in scleroderma. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, and Medline up to 1996 using the Cochrane Collaboration search strategy developed by Dickersin et al.(1994). Key words included: Raynaud's or Vasospasm, Scleroderma or Progressive Systematic Sclerosis or Connective Tissue Disease or Autoimmune Disease. Current Contents were searched up to and including April 7, 1997. All bibliographies of articles retrieved were searched and key experts in the area were contacted for additional and unpublished data. The initial search strategy included all languages. SELECTION CRITERIA: All randomized trials comparing cyclofenil versus placebo were eligible if they reported any clinical outcomes within the trial. DATA COLLECTION AND ANALYSIS: Data were abstracted independently by two reviewers (DF, AT). Peto's odds ratio (OR) was calculated for all dichotomous outcomes, and a weighted mean difference was calculated for all continuous outcomes. A fixed effects or random effects model was used if the data were homogeneous or heterogeneous respectively. MAIN RESULTS: One trial with 38 patients was included. There was a trend for Cyclofenil to demonstrate more improvement and more dropouts compared to placebo, but there were no statistically significant differences. REVIEWER'S CONCLUSIONS: Cyclofenil is not effective in the treatment of Raynaud's phenomenon secondary to scleroderma.

Ultrasonic assessment of ovulation in cyclofenil induced ovulatory cycles.

Graafian follicle growth was studied by ultrasound scanning during the peri-ovulatory period in 64 ovulatory cycles in 32 infertile patients on cyclofenil treatment, and compared with a control group of 32 patients with confirmed ovulatory cycles assessed on the basis of serum progesterone levels in the middle of the second half of the cycle. The mean maximum diameters of the leading follicles before ovulation were 21.9 +/- 0.6 (S.E.) mm and 24.4 +/- 0.5 (S.E.) mm, respectively for the cyclofenil group and the normal control group (P greater than 0.05). In 79% of the cyclofenil stimulated group and 83% of the spontaneous ovulation group, ultrasonic evidence of ovulation was present between 12 and 36 h after the initial increase in urine LH levels. Ultrasound scanning was found to be simple, and a quick method of monitoring graafian follicle development and ovulation on cyclofenil therapy and the cycles were comparable to the spontaneous ovulatory cycles as assessed on the basis of graafian follicle diameter, and the time of ovulation. Cervical score was not found to be useful to assess ovulation time in the cyclofenil treated group since 31.3% achieved a score of 10 or more on day -4, 93.8% within 24 h of ovulation and 24% on day 3 following the ovulation.

The effects of Cyclofenil on the Cervical Mucus Score (Insler).

Daily simultaneous cervical mucus evaluation and ultrasonography of the Graafian follicular growth and ovulation were studied (in the mid-cycle) in 8 infertile British women during 30 Cyclofenil-stimulated cycles, and compared with 18 non-stimulated normal ovulatory cycles in 12 subjects (controls). In the 16 Cyclofenil-induced ovulatory cycles, there was an early (5 days prior to the day of ultrasonic ovulation) Full Cervical Mucus Score (Insler) in 69% of the cycles, and the Full Cervical Mucus Score lasted for 7 days or more in 63% of the cycles. In 38%, there was persistence of the Full Cervical Mucus Score on the third day after ultrasonic ovulation. In the 14 Cyclofenil-treated anovulatory cycles, a Full Cervical Mucus Score was recorded on one or more occasions in the mid-cycle in 29% of the cycles. The classical teaching of prediction of the probable timing of ovulation by Cervical Mucus Scoring is not applicable to Cyclofenil-stimulated cycles.

[Medium term treatment and prophylaxis of dysfunctional metrorrhagia in adolescence]. / Trattamento a medio termine e profilassi delle metrorragie disfunzionali della adolescenza.

The authors compared the therapeutic effectiveness of these different pharmacological methods of preventing dysfunctional menometrorrhagia in adolescents, which were: 1) chorionic gonadotropin, 2) cyclofenil, 3) ovariostatics. Therapy was given during 2 menstrual cycles, and effects were evaluated both during the treatment and for the succeeding 2 cycles. Parameters followed were: a) clinical recovery, b) persistence of spotting, c) effectiveness in inducing ovulation. The results were equally good both in treatment with ovariostatics and ovulation inducers. The latter proved however, more effective during follow-up. Side-effects were very rare, so much so that, in no case was it necessary to suspend treatment.