Roll-to-Roll Nanoimprinting Metamaterials

We investigated continuous fabrication of a large area 2-D metamaterial comprising a metal dot array on a dielectric coated substrate. We demonstrated patterning of metal dots arrays of varying patterns and shapes with diameter of about 2.5 μm and metal-to-metal spacing from 0.3 to 2.5 μm using a nano-imprinting stamp on a roller. The pattern was first fabricated on a standard photolithography mask, reproduced onto a silicon wafer master mold, and then transferred to a flexible polymer mold that was wrapped around a metal roller. The method was used to pattern a thin Al layer on top of SiO2 on a flexible polymer substrate. The aluminum was coated with a resist and the roller moved over the substrate with adjustable speed and pressure to imprint the fine pattern into the resist. The resist was cured, and a very thin layer of residual resist was removed by RIE, followed by a standard etching treatment for patterning the aluminum layer.

The as-etched pattern had very few defects and the optical properties of the metamaterial were excellent and correlated well with simulations. This work has shown that low cost, rapid roll-to-roll processing of 2-D metamaterial structures is possible.

Fabrication and characterization of WO3/Ag/WO3 multilayer transparent anode with solution-processed WO3 for polymer light-emitting diodes

The dielectric/metal/dielectric multilayer is suitable for a transparent electrode because of its high-optical and high-electrical properties; however, it is fabricated by an expensive and inefficient multistep vacuum process. We present a WO3/Ag/WO3 (WAW) multilayer transparent anode with solution-processed WO3 for polymer light-emitting diodes (PLEDs). This WAW multilayer not only has high transmittance and low resistance but also can be easily and rapidly fabricated. We devised a novel method to deposit a thin WO3 layer by a solution process in an air environment. A tungstic acid solution was prepared from an aqueous solution of Na2WO4 and then converted to WO3 nanoparticles (NPs) by a thermal treatment. Thin WO3 NP layers form WAW multilayer with a thermal-evaporated Ag layer, and they improve the transmittance of the WAW multilayer because of its high transmittance and refractive index. Moreover, the surface of the WO3 layer is homogeneous and flat with low roughness because of the WO3 NP generation from the tungstic acid solution without aggregation. We performed optical simulation and experiments, and the optimized WAW multilayer had a high transmittance of 85% with a sheet resistance of 4 Ω/sq. Finally, PLEDs based on the WAW multilayer anode achieved a maximum luminance of 35,550 cd/m2 at 8 V, and this result implies that the solution-processed WAW multilayer is appropriate for use as a transparent anode in PLEDs.

Complementary treatment of siTERT for improving the antitumor effect of TERT-specific I-131 therapy

Sodium iodide symporter (NIS)-based radionuclide therapy provides an effective means of treating malignant tumors. However, it is sometimes inadequate because of limited effects on radio-resistant tumors, and thus, combination therapies with other therapeutic options have been requested to enhance its efficacy. Human telomerase reverse transcriptase (hTERT) has been reported to be involved in the progression of most cancers and also been viewed as a good candidate for targeting tumor. Application of TERT-specific radionuclide therapies using NIS gene transfer have been reported to treat TERT-positive tumors, but this approach only demonstrated tumor regression rather than eradication. As inhibiting TERT expression by introducing the hTERT-specific shRNA (siTERT) has been suggested as a therapeutic option, we investigated the complementary role of siTERT treatment after the TERT-specific I-131 therapy and its possibility as a novel anticancer therapeutic strategy. Retroviruses containing TERT promoter/NIS for TERT specific Radionuclide therapy and siTERT for TERT targeting antisense therapy were produced. Hep3B cells expressing TERT specific NIS (Hep3B-TERT/NIS) were xenografted into nude mouse and visualized with micro-SPECT/CT for monitoring NIS activity. The levels of hTERT mRNA, protein and its activity were confirmed by RT-PCR, Western blotting and Telomerase repeat amplification protocol assay. Cell proliferation was monitored by MTT assay and induced apoptosis was confirmed by Annexin-V-PI staining. Therapeutic effects of I-131 and/or siTERT were evaluated by clonogenic assay and mouse tumor model. Reduction of hTERT mRNA, protein and TERT activity by siTERT were observed in Hep3B-TERT/NIS cells. The viabilities of the infected cells were significantly decreased to 50% versus siScramble treated controls. The early apoptotic cell population was increased by siTERT. The survival rates of cells treated with siTERT or I-131 alone were 72.4±7.6% and 56.2±5.2%, respectively. However, the survival rate of cells treated with I-131 and siTERT were decreased to 22.1±2.8%. From mouse xenograft model, we also found that the siTERT gene therapy showed synergism to the radioiodine therapy for reducing tumor growth in vivo. Our Results suggested that complementary siTERT gene therapy offers a novel strategy of cancer therapy to improve the therapeutic efficacy of TERT-specific I-131.

Effect of a synthetic peroxisome proliferator-activated receptor-gamma (PPARγ) ligand on breast cancer cells

e14638

Background: Peroxisome proliferator-activated receptor-gamma (PPARγ) ligands have been identified as a potential source of therapy for human cancers. And, it is reported that PPAR-γ ligands could serve as negative regulators of breast cancer development and progression, but their mechanism is still unknown. The purpose of this study was to determine whether the PPAR- γ ligand induces cell cycle arrest and apoptosis of MDA-MB-231(ERα-negative) and MCF-7(ERα-positive) breast cancer cell. Methods: The effect of PPAR-γ ligands on the cell viability of breast cancer cells was determined using mitochondrial tetrazolium(MTT) assay. The cell cycle distribution and apoptosis induction were evaluated by using the flow cytometry. The expression of apoptosis-related proteins were measured with Western blot analysis. Results: The treatment of MDA-MB- 231 cell with PPAR-γ ligand, troglitazone was shown to induce cell cycle G1 arrest and induction of apoptosis. Moreover, troglitazone treatment, applied in a dose-dependent manner, caused a marked decrease in phosphorylated retinoblastoma(pRb), cyclin D1, D2, D3, cyclin dependent kinase(Cdk) 2, 4, and 6 expression as well as a significant increase in Cdk inhibitor, p21 and p27. Troglitazone showed antiproliferative effect on MCF-7 cell with tamoxifen, respectively and synergically. Troglitazone and tamoxifen could induce G1 arrest and apoptosis of MCF-7 cell, through upregulation of Bax and downregulation of Bcl-2 and cyclin D1. Conclusions: PPAR-γ ligand, troglitazone induces cell cycle arrest and apoptosis of MDA-MB-231 cell and increases the sensitivity of anti-hormonal therapy in MCF-7 cell. These results suggest that troglitazone has anticancer effect on both ERα-negative and positive breast cancer cells.

No significant financial relationships to disclose.

GSTP1 promoter hypermethylation during breast cancer development

Abstract #5042

Background. Promoter hypermethylation in precursor lesions of the breast cancer may be biomarkers of cancer risk and targets for cancer chemoprevention. GSTP1 is inactivated by promotor hypermethylation in invasive breast cancers. However, little is known about epigenetic silencing of GSTP1 gene by promoter hypermethylation in precursor lesions.
 Method. To determine the significance of GSTP1 promoter hypermethylation in breast carcinogenesis, methylation status of GSTP1 gene was studied by nested methylation-specific PCR and GSTP1 expression was studied by immunohistochemistry in invasive ductal carcinoma (IDC), ductal carcinoma in situ (DCIS), usual ductal hyperplasia (UDH) and normal breast tissue.
 Results. GSTP1 promoter hypermethylation was detected in 4/24 (16.7%) of UDH, 18/49 (36.7%) of DCIS, and 14/36 (38.9%) of IDC. No hypermethylation was detected in normal breast tissues. GSTP1 promoter hypermethylation was found to be progressively elevated during breast carcinogenesis (P < 0.01). GSTP1 promoter hypermethylation was associated with loss of GSTP1 expression (P < 0.01 for UDH, P < 0.001 for DCIS and IDC).
 Conclusion. Our results suggest that GSTP1 promoter hypermethylation is an early event in breast carcinogenesis and appears to functionally silence GSTP1 expression. GSTP1 promoter hypermethylation in the precursor lesions of breast cancer may be used as a target for cancer chemoprevention.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5042.

Induction of cell cycle arrest and apoptosis in breast cancer cells by troglitazone, a peroxisome proliferator-activated receptor-gamma (PPAR-γ) ligand

Abstract #5034

Background: Peroxisome proliferator-activated receptor-gamma(PPAR-γ) ligands inhibit cell proliferation and induce apoptosis in cancer cells. And, it is reported that PPAR-γ ligands could serve as negative regulators of breast cancer development and progression, but their mechanism is still unknown. Here we wished to determine whether the PPAR-γ ligand induces cell cycle arrest and apoptosis of MDA-MB-231(ERα-negative) and MCF-7(ERα-positive) breast cancer cell.
 Methods: The effect of PPAR-γ ligands on the cell viability of breast cancer cells was determined using mitochondrial tetrazolium(MTT) assay. The cell cycle distribution and apoptosis induction were evaluated by using the flow cytometry. The expression of apoptosis-related proteins were measured with Western blot analysis. Statistical analysis was performed using Student's t test, and p<0.05 was considered significant.
 Results: The treatment of MDA-MB-231 cell with PPAR-γ ligand, troglitazone was shown to induce cell cycle G1 arrest and induction of apoptosis. Moreover, troglitazone treatment, applied in a dose-dependent manner, caused a marked decrease in phosphorylated retinoblastoma(pRb), cyclin D1, D2, D3, cyclin dependent kinase(Cdk) 2, 4, and 6 expression as well as a significant increase in Cdk inhibitor, p21 and p27. Troglitazone showed antiproliferative effect on MCF-7 cell with tamoxifen, respectively and synergically. Troglitazone and tamoxifen could induce G1 arrest and apoptosis of MCF-7 cell, through upregulation of Bax and downregulation of Bcl-2 and cyclin D1.
 Conclusion: PPAR-γ ligand, troglitazone induces cell cycle arrest and apoptosis of MDA-MB-231 cell and increases the sensitivity of anti-hormonal therapy in MCF-7 cell. These results suggest that troglitazone has anticancer effect on both ERα-negative and positive breast cancer cells.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5034.

Phosphoinositide 3-OH kinase p85alpha and p110beta are essential for androgen receptor transactivation and tumor progression in prostate cancers

Phosphoinositide 3-OH kinases (PI3Ks) are a group of major intracellular signaling molecules. In our previous study, we found that inhibition of PI3K activity suppressed the androgen receptor (AR)-mediated gene expression in prostate cancer cells. The AR has been considered as a critical determinant for the development and progression of human prostate cancers. In this study, we sought to identify the PI3K isoforms involved in AR transactivation. Using a gene-specific small interference RNA (siRNA) approach, we determined that the regulatory isoform p85alpha and the catalytic isoform p110beta, but not p110alpha, were required for androgen-stimulated AR transactivation and cell proliferation in prostate cancer cells. Consistently, overexpression of wild-type p110beta but not p110alpha gene led to androgen-independent AR transactivation. Silencing p110beta gene in prostate cancer cells abolished tumor growth in nude mice. Of the dual (lipid and protein) kinase activities, p110beta's lipid kinase activity was required for AR transactivation. Further analysis by a chromatin immunoprecipitation assay showed that p110beta is indispensable for androgen-induced AR-DNA interaction. Finally, gene expression analysis of clinical specimens showed that both p85alpha and p110beta were highly expressed in malignant prostate tissues compared to the nonmalignant compartments, and their expression levels correlated significantly with disease progression. Taken together, our data demonstrated that p85alpha and p110beta are essential for androgen-stimulated AR transactivation, and their aberrant expression or activation might play an important role in prostate cancer progression.

Development of Canine Systemic Lupus Erythematosus Model

The purpose of this study was to develop a model for canine systemic lupus erythematosus. Systemic lupus erythematosus (SLE) is a systemic autoimmune syndrome defined by clinical and serological features, including arthritis, glomerulonephritis, dermatitis and autoantibodies. SLE was induced in eight normal dogs by immunization with heparan sulphate, the major glycosaminoglycan of the glomerular basement membrane. All the heparan sulphate-immunized dogs showed mild-to-moderate levels of proteinuria and skin disease. Cutaneous signs associated with SLE including alopecia, erythema, crusting, scaling and seborrhoea were observed. Immunohistological examination of the skin lesions revealed deposition of immunoglobulin M and complement in the dermal-epidermal junction. Three of eight dogs showed lameness. The antinuclear antibody tests were positive with the antibody titres higher than 1:128. Therefore, this experimental SLE model could be useful for studying immune-mediated skin disease and autoimmunity.

The heme pocket afforded by Gly117 is crucial for proper heme ligation and activity of CooA

CooA, a CO-sensing homodimeric transcription activator from Rhodospirillum rubrum, undergoes a conformational change in response to CO binding to its heme prosthetic group that allows it to bind specific DNA sequences. In a recent structural study (Lanzilotta, W. N., Schuller, D. J., Thorsteinsson, M. V., Kerby, R. L., Roberts, G. P., and Poulos, T. L. (2000) Nat. Struct. Biol. 7, 876-880), it was suggested that CO binding to CooA results in a modest repositioning of the C-helices that serve as the dimer interface. Gly(117) is one of the residues on the C-helix within 7 A of the heme iron on the Pro(2) side of the heme in CooA. Analysis of a series of Gly(117) variants revealed altered CO-sensing function and heme ligation states dependent on the size of the substituted amino acid at this position; bulky substitutions perturbed CooA both spectrally and functionally. A combination of spectroscopic and mutagenic studies showed that a representative Gly(117) variant, G117I CooA, was specifically perturbed in its Pro(2) ligation in both Fe(III) and Fe(II) forms, but comparison with other CooA variants indicated that perturbation of Pro(2) ligation is not the basis for the lack of CO response in G117I CooA. These results have led to the hypothesis that (i) the heme and the C-helix region move toward each other following CO binding and the interaction of the heme with the C-helix is crucial for CooA activation, and (ii) this event occurs only when a properly sized heme pocket is afforded.

Redox-mediated transcriptional activation in a CooA variant

CooA, the carbon monoxide-sensing transcription factor from Rhodospirillum rubrum, binds CO at a reduced (Fe(II)) heme moiety with resulting conformational changes that promote DNA binding. In this study, we report a variant of CooA, M124R, that is active in transcriptional activation in a redox-dependent manner. Where wild-type CooA is active only in the Fe(II) + CO form, M124R CooA is active in both Fe(II) + CO and Fe(III) forms. Analysis of the pH dependence of the activity of Fe(III) M124R CooA demonstrated that the activity was also coordination state-dependent with a five-coordinate, high-spin species identified as the active form and Cys(75) as the retained ligand. In contrast, the active Fe(II) + CO forms of both wild-type and M124R CooA are six-coordinate and low-spin with a protein ligand other than Cys(75), so that WT and Fe(III) M124R CooA are apparently achieving an active conformation despite two different heme coordination and ligation states. A hypothesis to explain these results is proposed. This study demonstrates the utility of CooA as a model system for the isolation of functionally interesting heme proteins.

Characterization of variants altered at the N-terminal proline, a novel heme-axial ligand in CooA, the CO-sensing transcriptional activator

CooA, the carbon monoxide-sensing transcription factor from Rhodospirillum rubrum, binds CO through a heme moiety resulting in conformational changes that promote DNA binding. The crystal structure shows that the N-terminal Pro(2) of one subunit (Met(1) is removed post-translationally) provides one ligand to the heme of the other subunit in the CooA homodimer. To determine the importance of this novel ligand and the contiguous residues to CooA function, we have altered the N terminus through two approaches: site-directed mutagenesis and regional randomization, and characterized the resulting CooA variants. While Pro(2) appears to be optimal for CooA function, it is not essential and a variety of studied variants at this position have substantial CO-sensing function. Surprisingly, even alterations that add a residue (where Pro(2) is replaced by Met(1)-Tyr(2), for example) accumulate heme-containing CooA with functional properties that are similar to those of wild-type CooA. Other nearby residues, such as Phe(5) and Asn(6) appear to be important for either the structural integrity or the function of CooA. These results are contrasted with those previously reported for alteration of the His(77) ligand on the opposite side of the heme.

In vitro and In vivo activities of LB 10827, a new oral cephalosporin, against respiratory pathogens

The in vitro antibacterial activities of LB 10827, a new oral cephalosporin, against common respiratory tract pathogens were compared with those of six beta-lactams (cefdinir, cefuroxime, cefprozil, penicillin G, amoxicillin-clavulanate, and ampicillin), two quinolones (trovafloxacin and ciprofloxacin), and one macrolide (clarithromycin). The MIC of LB 10827 at which 90% of the penicillin-resistant strains of Streptococcus pneumoniae tested were inhibited was 0.5 microg/ml, and the drug was 4- to 32-fold more active than the compared beta-lactams. The potent activity of LB 10827 against Haemophilus influenzae and Moraxella catarrhalis was retained, and the presence of beta-lactamase in both strains had little effect on the in vitro activity of the compound. Time-kill studies revealed that LB 10827 had bactericidal activity against these respiratory pathogens. This agent reduced original counts of all pathogens tested by >/=3 log(10) CFU/ml at the MIC, and the regrowth was completely prevented for 12 h. The potent in vitro antibacterial activity of LB 10827 against respiratory pathogens has been proved in both mouse pneumonia and neutropenic rat models. These results strongly suggest that this agent has potential for the treatment of respiratory tract infections.

Synthesis and antibacterial activities of novel C(3)-aminopyrimidinyl substituted cephalosporins including against respiratory tract pathogens

The variety of cephalosporins 1 and 2 which possessed C(3)-aminopyrimidinyl substituents were prepared and evaluated for their antibacterial activities. They exhibited excellent in vitro activities especially against respiratory tract pathogens such as penicillin resistant Streptococcus pneumonia. Moraxella catarrhalis and Haemophilus influenza.

Enhanced sensitivity of Streptomyces seoulensis to menadione by superfluous lipoamide dehydrogenase

Lipoamide dehydrogenase from Streptomyces seoulensis could facilitate menadione-mediated cytochrome c reduction, which was mostly inhibited by superoxide dismutase, indicating the obvious involvement of superoxide radical anion. In this reaction, the production of superoxide radical anion occurred via a menadione semiquinone radical anion. When exposed to menadione, lipoamide dehydrogenase-overexpressing cells showed a much lower survival rate with a concomitant decrease of intracellular protein thiol than the wild-type strain. These results suggest that lipoamide dehydrogenase is a facilitating agent in the redox cycling of quinone compounds in vivo as well as in vitro and could inevitably increase the potential toxicity of the compounds.

Sepiapterin reductase producing L-threo-dihydrobiopterin from Chlorobium tepidum

A novel type of NADPH-dependent sepiapterin reductase, which catalysed uniquely the reduction of sepiapterin to l-threo-dihydrobiopterin, was purified 533-fold from the cytosolic fraction of Chlorobium tepidum, with an overall yield of 3%. The native enzyme had a molecular mass of 55 kDa and SDS/PAGE revealed that the enzyme consists of two subunits with a molecular mass of 26 kDa. The enzyme was optimally active at pH8.8 and 50 degrees C. Apparent Km values for sepiapterin and NADPH were 21 and 6.2 microM, respectively, and the kcat value was 5.0 s-1. Diacetyl could also serve as a substrate, with a Km of 4.0 mM. The inhibitory effects of N-acetylserotonin, N-acetyldopamine and melatonin were very weak. The Ki value of N-acetyldopamine was measured as 400 microM. The N-terminal amino acid sequence was revealed as Met-Lys-His-Ile-Leu-Leu-Ile-Thr-Gly-Ala-Xaa-Lys - Lys - Ile - Xaa - Arg - Ala - Ile - Ala - Leu - Glu - Xaa - Ala - Arg - Xaa-Xaa-Xaa-His-His-His-, which shared relatively high sequence similarity with other sepiapterin reductases.

Lipoamide dehydrogenase from streptomyces seoulensis: biochemical and genetic properties

Lipoamide dehydrogenase was purified around 22-fold relative to the crude extracts of Streptomyces seoulensis with an overall yield of 9. 5%. The enzyme was composed of two identical subunits with a molecular mass of 54 kDa and contained 1 mol of FAD per mol of subunit. The absorption spectra of the enzyme revealed the absorption maxima of flavoprotein at 272, 349, and 457 nm. Catalytically active two-electron reduced lipoamide dehydrogenase was produced by anaerobic reduction with one equivalent of NADH. Addition of excess amount of NADH led to the four-electron reduced lipoamide dehydrogenase. The reaction of the enzyme in the reduction reaction of lipoamide or lipoic acid could be explained by a ping-pong mechanism like many other lipoamide dehydrogenases reported earlier. The enzyme also catalysed the reduction of various quinone compounds with NADH as electron donor via a ping-pong mechanism. The enzyme can catalyse a single electron transfer in case of quinone-reducing process, evidenced by the production of 1, 4-naphthosemiquinone radical anion. The quinone-reducing activity of the enzyme was dramatically inhibited by NAD+, indicating the involvement of four-electron reduced form. The structural gene for the enzyme was cloned using a DNA fragment PCR-amplified with the primers designed from N-terminal and internal amino acid sequences. The deduced amino acid sequence shared striking similarity with those of lipoamide dehydrogenases from prokaryotes and eukaryotes. The gene was named lpd. All tested Streptomyces contained one homologue of the lpd gene, which is consistent with the fact that most organisms contain only one lipoamide dehydrogenase.

Tepidopterin, 1-O-(L-threo-biopterin-2'-yl)-beta-N-acetylglucosamine from Chlorobium tepidum

A novel pterin compound, designated as tepidopterin, was detected from a thermophilic photosynthetic green sulphur bacterium, Chlorobium tepidum. The amount of tepidopterin inside the cell was estimated to be 2-5 micromol g(-1) dry weight of cell. This compound was purified through a high performance liquid chromatography using preparative DeltaPak C18 column. This compound was characterized by chromatographic behavior and by absorption and fluorescence properties. Its structure was determined to be 1-O-(L-threo-biopterin-2'-yl)-beta-N-acetylglucosamine by 1D- and 2D-NMR spectroscopy, mass spectrometry and CD. The relative amount of tetrahydrotepidopterin was estimated to be 96.7% inside the cell, that of dihydrotepidopterin 2.9%, and that of fully oxidized tepidopterin 0.4%. The amount of tepidopterin within the cell increased continuously until the beginning of the stationary phase of the cell growth.

Unique isozymes of superoxide dismutase in Streptomyces griseus

Two unique isozymes of superoxide dismutase (EC 1.15.1.1) were purified to apparent homogeneity from Streptomyces griseus by a purification procedure consisting of ammonium sulfate precipitation and chromatographies on DEAE Sephacel, Sephacryl S-200, and DEAE 5PW. Superoxide dismutase I was composed of four identical subunits of 13.0 kDa. The absorption spectrum of superoxide dismutase I exhibited absorption bands at 276 and 378 nm and a broad shoulder at 530 nm. The g values of electron paramagnetic resonance spectrum of superoxide dismutase I were g1 = 2.304, g2 = 2.248, and g3 = 2.012 and the resonance centered at g3 = 2.012 was split into triplet, indicating nickel-containing superoxide dismutase. Superoxide dismutase I contained 0.89 g-atom of nickel per mole of 13.0-kDa subunit. Superoxide dismutase II was composed of four identical subunits of 22.0 kDa. The absorption spectrum of superoxide dismutase II showed the featureless absorption band in the range of 300-500 nm. The g values of electron paramagnetic resonance spectrum of superoxide dismutase II were gz = 4.762, gx = 4.072, and gy = 3.742, indicating iron-containing superoxide dismutase. Superoxide dismutase II uniquely contains 0.40 g-atom of iron per mole of monomer as well as 0.43 g-atom of zinc per mole of monomer. The immunological cross-reactivity between two isozymes was not found. Nickel-containing superoxide dismutase was widely distributed within the genus Streptomyces; however, iron- and zinc-containing superoxide dismutase was not found in S. albus and S. longisporoflavus, on the basis of the immunological cross-reactivity.