A Selective ERRα/γ Inverse Agonist, SLU-PP-1072, Inhibits the Warburg Effect and Induces Apoptosis in Prostate Cancer Cells

The estrogen related receptors (ERRs) are a subgroup of nuclear receptors that play a role in regulation of cellular metabolism. Prostate cancer (PCa) cells display altered metabolic signatures, such as the Warburg effect, and the ERRs have been implicated in driving this phenotype. Despite the lack of a known endogenous ligand, synthetic ligands that target the ERRs have been discovered. For example, the ERRα inverse agonist XCT790 modulates metabolic pathways in PCa cells, but it also functions as a mitochondrial uncoupler independent of targeting ERRα. Here, we describe a novel dual ERRα/γ inverse agonist, SLU-PP-1072, derived from the GSK4716 ERRγ agonist scaffold that is distinct from the XCT790 scaffold. SLU-PP-1072 alters PCa cell metabolism and gene expression, resulting in cell cycle dysregulation and increased apoptosis without acute mitochondrial uncoupling activity. Our data suggest that inhibition of ERRα/γ may be beneficial in treatment of PCa, and SLU-PP-1072 provides a unique chemical tool to evaluate the pharmacology of ERRα and ERRγ.

Identification and Structure-Activity Relationships of Novel Compounds that Potentiate the Activities of Antibiotics in Escherichia coli

In Gram-negative bacteria, efflux pumps are able to prevent effective cellular concentrations from being achieved for a number of antibiotics. Small molecule adjuvants that act as efflux pump inhibitors (EPIs) have the potential to reinvigorate existing antibiotics that are currently ineffective due to efflux mechanisms. Through a combination of rigorous experimental screening and in silico virtual screening, we recently identified novel classes of EPIs that interact with the membrane fusion protein AcrA, a critical component of the AcrAB-TolC efflux pump in Escherichia coli. Herein, we present initial optimization efforts and structure-activity relationships around one of those previously described hits, NSC 60339 (1). From these efforts we identified two compounds, SLUPP-225 (17h) and SLUPP-417 (17o), which demonstrate favorable properties as potential EPIs in E. coli cells including the ability to penetrate the outer membrane, improved inhibition of efflux relative to 1, and potentiation of the activity of novobiocin and erythromycin.

Reviving Antibiotics: Efflux Pump Inhibitors That Interact with AcrA, a Membrane Fusion Protein of the AcrAB-TolC Multidrug Efflux Pump

Antibiotic resistance is a major threat to human welfare. Inhibitors of multidrug efflux pumps (EPIs) are promising alternative therapeutics that could revive activities of antibiotics and reduce bacterial virulence. Identification of new druggable sites for inhibition is critical for the development of effective EPIs, especially in light of constantly emerging resistance. Here, we describe EPIs that interact with periplasmic membrane fusion proteins, critical components of efflux pumps that are responsible for the activation of the transporter and the recruitment of the outer-membrane channel. The discovered EPIs bind to AcrA, a component of the prototypical AcrAB-TolC pump, change its structure in vivo, inhibit efflux of fluorescent probes, and potentiate the activities of antibiotics in Escherichia coli and other Gram-negative bacteria. Our findings expand the chemical and mechanistic diversity of EPIs, suggest the mechanism for regulation of the efflux pump assembly and activity, and provide a promising path for reviving the activities of antibiotics in resistant bacteria.

Synthesis, photophysical characterization, and photoelectrochemical evaluation of a palladium porphyrin sensitizer for TiO2-based dye-sensitized solar cells

An unsymmetrical (A3B) palladium porphyrin bearing a cyanoacrylic acid at one meso position has been synthesized for evaluation as a photosensitizer in dye-sensitized solar cells based on titanium dioxide ( TiO 2) as a comparison to other metalloporphyrins and as a proxy for other potential triplet-state photosensitizer compounds. The synthesis of this palladium porphyrin has provided new insight into the mechanism and product distribution of decarboxylative hydrolysis of malonic acid when attached at the porphyrin meso position. A crystal structure determination for a meso-formyl palladium porphyrin has been determined, showing saddle-distortion of the porphyrin core. The photophysical behavior of the palladium porphyrin sensitizer and its performance in photoelectrochemical cells are described and interpreted in the context of bimolecular excited state quenching pathways including oxygen sensitization, triplet–triplet annihilation and electron transfer events. Palladium porphyrins are proposed as a sensitizer class with potential for high efficiency dye-sensitized solar cells, but with the caveat that some overpotential for electron injection is necessary to compete against the multiple decay pathways that are specially available to triplet state photosensitizers.

Tuning Interfacial Electron Transfer in Nanostructured Cuprous Oxide Photoelectrochemical Cells with Charge-Selective Molecular Coatings

The coating of nanostructured films of cuprous oxide with electroactive molecules strongly affects their photoelectrochemical performance in nonaqueous photocells, with photocurrent density increased up to an order of magnitude relative to bare cuprous oxide films or almost completely suppressed, depending on the choice of molecular adsorbant. Among adsorbants that enhance photocurrent, a strong variance of photoelectrochemical behavior is observed with changes in the molecular structure of the sensitizer, associated with differences in the reorganization energy and molecular size, which are interpreted to enhance forward electron transport and impede electrolyte/photocathode recombination, respectively. These results demonstrate that nanostructured cuprous oxide is a promising cathode material for p-type dye-sensitized solar cells.

Templated electrodeposition and photocatalytic activity of cuprous oxide nanorod arrays

Cuprous oxide (Cu2O) nanorod arrays have been prepared via a novel templated electrodeposition process and were characterized for their photocatalytic behavior in nonaqueous photoelectrochemical cells. Zinc oxide (ZnO) nanorod films serve as sacrificial templates for the in situ formation of polymer nanopore membranes on transparent conductive oxide substrates. Nitrocellulose and poly(lactic acid) are effective membrane-forming polymers that exhibit different modes of template formation, with nitrocellulose forming conformal coatings on the ZnO surface while poly(lactic acid) acts as an amorphous pore-filling material. Robust template formation is sensitive to the seeding method used to prepare the precursor ZnO nanorod films. Photoelectrochemical cells prepared from electrodeposited Cu2O films using methyl viologen as a redox shuttle in acetonitrile electrolyte exhibit significant charge recombination that can be partially suppressed by a combination of surface passivation methods. Surface-passivated nanostructured Cu2O films show enhanced photocurrent relative to planar electrodeposited Cu2O films of similar thickness. We have obtained the highest photocurrent ever reported for electrodeposited Cu2O in a nonaqueous photoelectrochemical cell.

Electron transport in acceptor-sensitized polymer-oxide solar cells: the importance of surface dipoles and electron cascade effects

Fullerene and acenequinone compounds have been examined as electron mediators between a p-type semiconductive polymer and two n-type oxide semiconductors. Composite interlayer materials and photovoltaic test cells were assembled and studied for their fluorescence quenching, current-voltage, and quantum efficiency behavior to characterize the efficacy of the acceptor-sensitizers as electron-selective interlayers. The sensitizers are generally more effective with titanium dioxide than with zinc oxide, due to the difference in magnitude of dipole-induced vacuum level shifts at the respective oxide interfaces. In titanium dioxide-based solar cells, where dipole effects are weak, photovoltage and fill factor increase in a trend that matches the increase in the first reduction potential of the acceptor-sensitizers. Photosensitization of the oxide semiconductor by the acceptor-sensitizers is observed to operate either in parallel with the polymer as an alternate photosensitizer or in series with the polymer in a two-photon process, according to an acceptor-sensitizer's first reduction potential. In zinc oxide-based solar cells, where dipole effects are stronger, the acceptor-sensitizers impaired most devices, which is attributed to an upward shift of the oxide's conduction band edge caused by dipole-induced vacuum level shifts. These results have broad implications for designing electron-selective interlayers and solid-state photocells using sensitized oxide semiconductors.

Consumer health information seeking on the Internet: the state of the art

Increasingly, consumers engage in health information seeking via the Internet. Taking a communication perspective, this review argues why public health professionals should be concerned about the topic, considers potential benefits, synthesizes quality concerns, identifies criteria for evaluating online health information and critiques the literature. More than 70 000 websites disseminate health information; in excess of 50 million people seek health information online, with likely consequences for the health care system. The Internet offers widespread access to health information, and the advantages of interactivity, information tailoring and anonymity. However, access is inequitable and use is hindered further by navigational challenges due to numerous design features (e.g. disorganization, technical language and lack of permanence). Increasingly, critics question the quality of online health information; limited research indicates that much is inaccurate. Meager information-evaluation skills add to consumers' vulnerability, and reinforce the need for quality standards and widespread criteria for evaluating health information. Extant literature can be characterized as speculative, comprised of basic 'how to' presentations, with little empirical research. Future research needs to address the Internet as part of the larger health communication system and take advantage of incorporating extant communication concepts. Not only should research focus on the 'net-gap' and information quality, it also should address the inherently communicative and transactional quality of Internet use. Both interpersonal and mass communication concepts open avenues for investigation and understanding the influence of the Internet on health beliefs and behaviors, health care, medical outcomes, and the health care system.

Immunoreactive growth hormone receptor/binding protein is present on fibroblasts and in serum of Laron-type dwarfs

Laron-type dwarfism is an autosomal recessive disorder characterised by extreme growth retardation and growth hormone (GH) resistance and has been shown in some cases to be associated with mutations in the GH receptor gene. Limited data suggest that in this condition specific liver GH binding is absent. In the majority of reported cases specific GH binding is also absent in serum. However it is not known whether the GH receptor and/or the serum GH binding protein are expressed in this condition. Using the techniques of immunohistochemistry and Northern blotting we have demonstrated that in cultured skin fibroblasts derived from four patients with Laron-type dwarfism the GH receptor gene is transcribed and the GH receptor protein is expressed on the cell surface. Further study of one of these patients, who has not previously been reported, has also revealed low but detectable levels of GH binding protein in serum using a two-site immunradiometric assay which does not depend on GH binding. These results indicate that the growth hormone receptor/binding protein is expressed in Laron-type dwarfism.

Demonstration and localization of growth hormone receptor in human skin and skin fibroblasts

Clinical evidence suggests that skin is responsive to GH status in vivo. We sought to demonstrate the presence of GH receptors in human skin and in cultured skin fibroblasts using the techniques of immunohistochemistry and northern blotting. Human foreskin was obtained at surgery for preparation of sections and primary fibroblast cultures. Skin sections and fibroblast monolayers were immunostained using a monoclonal antibody which recognizes the hGH receptor (MAb 263). Positive immunoperoxidase staining was seen in all epidermal layers except the stratum corneum, in dermal sweat and sebaceous glands, and in dermal fibroblasts. In cultured fibroblasts capping of surface GH receptor was observed after aqueous formaldehyde fixation, whereas fixation in Carnoy's solution resulted in granular cytoplasmic staining. Fibroblast poly A+ RNA was prepared from cultured skin fibroblasts, separated by denaturing agarose gel electrophoresis, blotted onto nitrocellulose, and hybridized to a 32P-labeled, 847 base pair (bp) hGH receptor complementary DNA (cDNA) clone. Human liver and non-pregnant rabbit liver total RNA were used as controls. Fibroblast poly A+ RNA contained a single hybridizing species of approximately 5.2 kilobase. Human liver total RNA also contained a single hybridizing species of 4.9 kilobase. We have demonstrated the presence of GH receptor protein in human skin and growth hormone receptor mRNA and protein in cultured human skin fibroblasts. These observations suggest that GH may indeed have a direct role in modulating keratinocyte and fibroblast function.

Autoradiographic localization of insulin-like growth factor I binding sites in the bovine adrenal gland and on cultured bovine adrenal chromaffin cells

Abstract Previous studies have reported the presence of binding sites for insulin-like growth factor I (IGF-I) in membranes prepared from isolated bovine adrenal medullary cells, and IGF-I was found to regulate the secretory function of bovine chromaffin cells. In the present study, binding sites for IGF-I have been localized in sections of bovine adrenal gland and on cultured bovine adrenal medullary cells, using [(125) l][Thr(59)]-IGF-l as the ligand in conjunction with qualitative autoradiographic techniques. Binding sites were present throughout the adrenal gland and were distributed evenly over all cortical cell layers and over both adrenaline and noradrenaline cell types in the medulla. They were also present at lower density over blood vessels and nerve bundles and over the capsule. The binding of radioligand was to a single class of sites with K(d) 0.61 nM, and was completely displaced by excess unlabelled [Thr(59)]-IGF-l and by insulin (Actrapid, K(d) 1.04muM). Binding sites were also identified on single cells in primary monolayer cultures of bovine adrenal medullary cells. More than 96% of the cells possessed binding sites, although only 85% of such cells were chromaffin cells, as previously determined from dopamine beta-hydroxylase immunohistochemical staining. The results suggest that IGF-I may affect the maturation, growth or function not only of adrenal chromaffin cells but also of many others cell types in this tissue.

Visual demonstration of growth hormone receptors on human growth plate chondrocytes

The sites of action of GH in the human infant remain unclear; recent evidence in animals suggests direct actions on growth plate and other tissues. We have used a monoclonal antibody recognizing the human GH receptor to visually identify and localize GH receptors in the human infant growth plate. Sternochondral cartilage was obtained at postmortem from infants dying of sudden infant death (n = 20), and either decalcified, fixed, and cut into longitudinal sections or digested with collagenase for monolayer culture of chondrocytes. Sections of cultured chondrocytes were stained immunocytochemically with a monoclonal antibody recognizing human GH receptor (MAb 263), using an avidin-biotin system. Sternochondral cartilage was also obtained at operation from adolescents undergoing sternochondroplasty. In infant tissue, GH receptor was identified in sections in chondrocytes of the proliferative and hypertrophic layers, in perichondrium, in osteocytes in new bone, and in hemopoietic precursor cells in marrow. Cultured chondrocytes showed heterogeneous staining for GH receptor. With prolonged culture from 5-8 days, the pattern of staining changed from individual cells to groups of cells. [125I]Human (h)GH showed specific binding to chondrocyte monolayer (0.6 +/- 0.3%), confirmed visually on emulsion autoradiography. In support of specificity of MAb263, it was able to displace [125I]hGH from monolayers by 35%. Adolescent cultured chondrocytes failed to demonstrate specific binding of [125I]hGH. We conclude that GH receptors are widely distributed in a range of mesenchyme cells in the human infant growth plate, including bone and hemopoietic precursors. The expression of these receptors appears to be maturation dependent in both intact tissue and culture, while they may no longer be expressed after the peak growth phase of puberty.

The ontogeny of growth hormone receptors in the rabbit tibia

To address the question of the mode of action of GH in stimulating longitudinal bone growth, we have used a panel of anti-GH receptor monoclonal antibodies to demonstrate GH receptors in the rabbit tibia and have studied the ontogeny of these receptors. In the neonate, receptors were localized in the hypertrophic zone between the cartilage canals, a region that develops into a secondary ossification center. In support of this finding, receptors were also localized on monolayer cultures of human infant costal chondrocytes. In 20- and 50-day-old rabbits, receptors were localized on reserve and proliferative chondrocytes in the growth plate. In 50- and 130-day-old rabbits receptors were localized on proliferative chondrocytes in the condylar cartilage. In older (180-day-old) rabbits with closed growth plates, GH receptors could not be detected, even in condylar cartilage. These results support the case for revision of the somatomedin hypothesis to accommodate a direct interaction between GH and receptors on epiphyseal chondrocytes.

Mitogenic effects of growth hormone in cultured human fibroblasts. Evidence for action via local insulin-like growth factor I production

We examined human growth hormone's (hGH) effect on mitogenesis in cultured human fibroblasts, and the role of local insulin-like growth factor I (IGF-I). With 0.5% human hypopituitary serum (HPS), hGH increased thymidine incorporation (TI) over serum-free medium dose responsively, with half-maximal effect at 10 ng/ml (0.5 nM) (hGH 127 +/- 8.8%; IGF-I 107 +/- 1.7% [SEM]) (n = 10). Similarly, with 0.5% HPS, hGH and IGF-I increased cell replication by 172 +/- 8.2% and 169 +/- 25%, respectively (n = 4). Specific IGF-I monoclonal antibody (Sm1.2) dose dependently blunted TI stimulated by 10 ng/ml hGH or IGF-I (at 1:1000, 38 +/- 6.5% and 30 +/- 14% reduction, respectively). Sm1.2 also reduced cell replication by both 10 ng/ml hGH and IGF-I, respectively, to 32% and 42% of stimulated values. Dexamethasone (0.1 microM) synergistically enhanced TI by both IGF-I and hGH. A 28-h time course for TI showed that hGH stimulated a similar peak to IGF-I, lagging in its effect by 4-10 h. We have provided further evidence that hGH stimulates growth of cultured human fibroblasts via local IGF-I production, consistent with IGF-I's paracrine-autocrine role.