Light-driven nanoscale vectorial currents.

Controlled charge flows are fundamental to many areas of science and technology, serving as carriers of energy and information, as probes of material properties and dynamics1 and as a means of revealing2,3 or even inducing4,5 broken symmetries. Emerging methods for light-based current control5-16 offer particularly promising routes beyond the speed and adaptability limitations of conventional voltage-driven systems. However, optical generation and manipulation of currents at nanometre spatial scales remains a basic challenge and a crucial step towards scalable optoelectronic systems for microelectronics and information science. Here we introduce vectorial optoelectronic metasurfaces in which ultrafast light pulses induce local directional charge flows around symmetry-broken plasmonic nanostructures, with tunable responses and arbitrary patterning down to subdiffractive nanometre scales. Local symmetries and vectorial currents are revealed by polarization-dependent and wavelength-sensitive electrical readout and terahertz (THz) emission, whereas spatially tailored global currents are demonstrated in the direct generation of elusive broadband THz vector beams17. We show that, in graphene, a detailed interplay between electrodynamic, thermodynamic and hydrodynamic degrees of freedom gives rise to rapidly evolving nanoscale driving forces and charge flows under the extremely spatially and temporally localized excitation. These results set the stage for versatile patterning and optical control over nanoscale currents in materials diagnostics, THz spectroscopies, nanomagnetism and ultrafast information processing.

Metasurface-based varifocal Alvarez lens at microwave frequencies.

Lenses with a tunable focus are highly desirable but remain a challenge. Here, we demonstrate a microwave varifocal meta-lens based on the Alvarez lens principle, consisting of two mechanically movable tri-layer metasurface phase plates with reversed cubic spatial profiles. The manufactured multilayer Alvarez meta-lens enables microwave beam collimation/focusing at frequencies centered at 7.5 GHz, and shows one octave focal length tunability when transversely translating the phase plates by 8 cm. The measurements reveal a gain enhancement up to 15 dB, 3-dB beam width down to 3.5∘, and relatively broad 3-dB bandwidth of 3 GHz. These advantageous characteristics, along with its simplicity, compactness, and lightweightness, make the demonstrated flat Alvarez meta-lens suitable for deployment in many microwave systems.

Mycobacterium tuberculosis encodes a YhhN family membrane protein with lysoplasmalogenase activity that protects against toxic host lysolipids.

The pathogen Mycobacterium tuberculosis (M.tb) resides in human macrophages, wherein it exploits host lipids for survival. However, little is known about the interaction between M.tb and macrophage plasmalogens, a subclass of glycerophospholipids with a vinyl ether bond at the sn-1 position of the glycerol backbone. Lysoplasmalogens, produced from plasmalogens by hydrolysis at the sn-2 carbon by phospholipase A2, are potentially toxic but can be broken down by host lysoplasmalogenase, an integral membrane protein of the YhhN family that hydrolyzes the vinyl ether bond to release a fatty aldehyde and glycerophospho-ethanolamine or glycerophospho-choline. Curiously, M.tb encodes its own YhhN protein (MtbYhhN), despite having no endogenous plasmalogens. To understand the purpose of this protein, the gene for MtbYhhN (Rv1401) was cloned and expressed in Mycobacterium smegmatis (M.smeg). We found the partially purified protein exhibited abundant lysoplasmalogenase activity specific for lysoplasmenylethanolamine or lysoplasmenylcholine (pLPC) (Vmax∼15.5 µmol/min/mg; Km∼83 µM). Based on cell density, we determined that lysoplasmenylethanolamine, pLPC, lysophosphatidylcholine, and lysophosphatidylethanolamine were not toxic to M.smeg cells, but pLPC and LPC were highly toxic to M.smeg spheroplasts, which are cell wall-deficient mycobacterial forms. Importantly, spheroplasts prepared from M.smeg cells overexpressing MtbYhhN were protected from membrane disruption/lysis by pLPC, which was rapidly depleted from the media. Finally, we found that overexpression of full-length MtbYhhN in M.smeg increased its survival within human macrophages by 2.6-fold compared to vector controls. These data support the hypothesis that MtbYhhN protein confers a growth advantage for mycobacteria in macrophages by cleaving toxic host pLPC into potentially energy-producing products.

Loss of apelin blocks the emergence of sprouting angiogenesis in experimental tumors.

Angiogenesis inhibitor drugs targeting vascular endothelial growth factor (VEGF) signaling to the endothelial cell (EC) are used to treat various cancer types. However, primary or secondary resistance to therapy is common. Clinical and pre-clinical studies suggest that alternative pro-angiogenic factors are upregulated after VEGF pathway inhibition. Therefore, identification of alternative pro-angiogenic pathway(s) is critical for the development of more effective anti-angiogenic therapy. Here we study the role of apelin as a pro-angiogenic G-protein-coupled receptor ligand in tumor growth and angiogenesis. We found that loss of apelin in mice delayed the primary tumor growth of Lewis lung carcinoma 1 and B16F10 melanoma when combined with the VEGF receptor tyrosine kinase inhibitor, sunitinib. Targeting apelin in combination with sunitinib markedly reduced the tumor vessel density, and decreased microvessel remodeling. Apelin loss reduced angiogenic sprouting and tip cell marker gene expression in comparison to the sunitinib-alone-treated mice. Single-cell RNA sequencing of tumor EC demonstrated that the loss of apelin prevented EC tip cell differentiation. Thus, apelin is a potent pro-angiogenic cue that supports initiation of tumor neovascularization. Together, our data suggest that targeting apelin may be useful as adjuvant therapy in combination with VEGF signaling inhibition to inhibit the growth of advanced tumors.

FGD5 regulates endothelial cell PI3 kinase-ß to promote neo-angiogenesis.

Angiogenesis is required in embryonic development and tissue repair in the adult. Vascular endothelial growth factor (VEGF) initiates angiogenesis, and VEGF or its receptor is targeted therapeutically to block pathological angiogenesis. Additional pro-angiogenic cues, such as CXCL12 acting via the CXCR4 receptor, co-operate with VEGF/VEGFR2 to cue vascular patterning. We studied the role of FGD5, an endothelial Rho GTP/GDP exchange factor (RhoGEF), to regulate CXCR4-dependent signals in the endothelial cell (EC). Patient-derived renal cell carcinomas produce a complex milieu of growth factors that stimulated sprouting angiogenesis and endothelial tip cell differentiation ex vivo that was blocked by EC FGD5 loss. In a simplified model, CXCL12 augmented sprouting and tip gene expression under conditions where VEGF was limiting. CXCL12-stimulated tip cell differentiation was dependent on PI3 kinase (PI3K)-ß activity. Knockdown of EC FGD5 abolished CXCR4 signaling to PI3K-ß and Akt. Further, inhibition of Rac1, a Rho GTPase required for PI3K-ß activity, recapitulated the signaling defects of FGD5 deficiency, suggesting that FGD5 may regulate PI3K-ß activity through Rac1. Overexpression of a RhoGEF deficient, Dbl domain-deleted FGD5 mutant reduced CXCL12-stimulated Akt phosphorylation and failed to rescue PI3K signaling in native FGD5-deficient EC, indicating that FGD5 RhoGEF activity is required for FDG5 function. Endothelial expression of mutant PI3K-ß with an inactivated Rho binding domain confirmed that CXCL12-stimulated PI3K activity in EC requires Rac1-GTP co-regulation. Together, this data identify the role of FGD5 to generate Rac1-GTP to regulate pro-angiogenic CXCR4-dependent PI3K-ß signaling in EC. Inhibition of FGD5 activity may complement current angiogenesis inhibitor drugs.

Pharmacological and cell-specific genetic PI3Kα inhibition worsens cardiac remodeling after myocardial infarction.

BACKGROUND: PI3Kα (Phosphoinositide 3-kinase α) regulates multiple downstream signaling pathways controlling cell survival, growth, and proliferation and is an attractive therapeutic target in cancer and obesity. The clinically-approved PI3Kα inhibitor, BYL719, is in further clinical trials for cancer and overgrowth syndrome. However, the potential impact of PI3Kα inhibition on the heart and following myocardial infarction (MI) is unclear. We aim to determine whether PI3Kα inhibition affects cardiac physiology and post-MI remodeling and to elucidate the underlying molecular mechanisms. METHODS AND RESULTS: Wildtype (WT) 12-wk old male mice receiving BYL719 (daily, p.o.) for 10 days showed reduction in left ventricular longitudinal strain with normal ejection fraction, weight loss, mild cardiac atrophy, body composition alteration, and prolonged QTC interval. RNASeq analysis showed gene expression changes in multiple pathways including extracellular matrix remodeling and signaling complexes. After MI, both p110α and phospho-Akt protein levels were increased in human and mouse hearts. Pharmacological PI3Kα inhibition aggravated cardiac dysfunction and resulted in adverse post-MI remodeling, with increased apoptosis, elevated inflammation, suppressed hypertrophy, decreased coronary blood vessel density, and inhibited Akt/GSK3ß/eNOS signaling. Selective genetic ablation of PI3Kα in endothelial cells was associated with worsened post-MI cardiac function and reduced coronary blood vessel density. In vitro, BYL719 suppressed Akt/eNOS activation, cell viability, proliferation, and angiogenic sprouting in coronary and human umbilical vein endothelial cells. Cardiomyocyte-specific genetic PI3Kα ablation resulted in mild cardiac systolic dysfunction at baseline. After MI, cardiac function markedly deteriorated with increased mortality concordant with greater apoptosis and reduced hypertrophy. In isolated adult mouse cardiomyocytes, BYL719 decreased hypoxia-associated activation of Akt/GSK3ß signaling and cell survival. CONCLUSIONS: PI3Kα is required for cell survival (endothelial cells and cardiomyocytes) hypertrophic response, and angiogenesis to maintain cardiac function after MI. Therefore, PI3Kα inhibition that is used as anti-cancer treatment, can be cardiotoxic, especially after MI.

Space-Time Quantum Metasurfaces.

Metasurfaces have recently entered the realm of quantum photonics, enabling manipulation of quantum light using a compact nanophotonic platform. Realizing the full potential of metasurfaces at the deepest quantum level requires the ability to tune coherent light-matter interactions continuously in space and time. Here, we introduce the concept of space-time quantum metasurfaces for arbitrary control of the spectral, spatial, and spin properties of nonclassical light using a compact photonic platform. We show that space-time quantum metasurfaces allow on-demand tailoring of entanglement among all degrees of freedom of a single photon. We also show that spatiotemporal modulation induces asymmetry at the fundamental level of quantum fluctuations, resulting in the generation of steered and vortex photon pairs out of vacuum. Space-time quantum metasurfaces have the potential to enable novel photonic functionalities, such as encoding quantum information into high-dimensional color qudits using designer modulation protocols, sculpting multispectral and multispatial modes in spontaneous emission, and generating reconfigurable hyperentanglement for high-capacity quantum communications.

Caspase-11 promotes the fusion of phagosomes harboring pathogenic bacteria with lysosomes by modulating actin polymerization.

Inflammasomes are multiprotein complexes that include members of the NLR (nucleotide-binding domain leucine-rich repeat containing) family and caspase-1. Once bacterial molecules are sensed within the macrophage, the inflammasome is assembled, mediating the activation of caspase-1. Caspase-11 mediates caspase-1 activation in response to lipopolysaccharide and bacterial toxins, and yet its role during bacterial infection is unknown. Here, we demonstrated that caspase-11 was dispensable for caspase-1 activation in response to Legionella, Salmonella, Francisella, and Listeria. We also determined that active mouse caspase-11 was required for restriction of L. pneumophila infection. Similarly, human caspase-4 and caspase-5, homologs of mouse caspase-11, cooperated to restrict L. pneumophila infection in human macrophages. Caspase-11 promoted the fusion of the L. pneumophila vacuole with lysosomes by modulating actin polymerization through cofilin. However, caspase-11 was dispensable for the fusion of lysosomes with phagosomes containing nonpathogenic bacteria, uncovering a fundamental difference in the trafficking of phagosomes according to their cargo.

PPARγ is critical for Mycobacterium tuberculosis induction of Mcl-1 and limitation of human macrophage apoptosis.

Peroxisome proliferator-activated receptor (PPAR)γ is a global transcriptional regulator associated with anti-inflammatory actions. It is highly expressed in alveolar macrophages (AMs), which are unable to clear the intracellular pathogen Mycobacterium tuberculosis (M.tb). Although M.tb infection induces PPARγ in human macrophages, which contributes to M.tb growth, the mechanisms underlying this are largely unknown. We undertook NanoString gene expression analysis to identify novel PPARγ effectors that condition macrophages to be more susceptible to M.tb infection. This revealed several genes that are differentially regulated in response to PPARγ silencing during M.tb infection, including the Bcl-2 family members Bax (pro-apoptotic) and Mcl-1 (pro-survival). Apoptosis is an important defense mechanism that prevents the growth of intracellular microbes, including M.tb, but is limited by virulent M.tb. This suggested that M.tb differentially regulates Mcl-1 and Bax expression through PPARγ to limit apoptosis. In support of this, gene and protein expression analysis revealed that Mcl-1 expression is driven by PPARγ during M.tb infection in human macrophages. Further, 15-lipoxygenase (15-LOX) is critical for PPARγ activity and Mcl-1 expression. We also determined that PPARγ and 15-LOX regulate macrophage apoptosis during M.tb infection, and that pre-clinical therapeutics that inhibit Mcl-1 activity significantly limit M.tb intracellular growth in both human macrophages and an in vitro TB granuloma model. In conclusion, identification of the novel PPARγ effector Mcl-1 has determined PPARγ and 15-LOX are critical regulators of apoptosis during M.tb infection and new potential targets for host-directed therapy for M.tb.

The Lung Mucosa Environment in the Elderly Increases Host Susceptibility to Mycobacterium tuberculosis Infection.

As we age, there is an increased risk for the development of tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) infection. Few studies consider that age-associated changes in the alveolar lining fluid (ALF) may increase susceptibility by altering soluble mediators of innate immunity. We assessed the impact of adult or elderly human ALF during Mtb infection in vitro and in vivo. We identified amplification of pro-oxidative and proinflammatory pathways in elderly ALF and decreased binding capability of surfactant-associated surfactant protein A (SP-A) and surfactant protein D (SP-D) to Mtb. Human macrophages infected with elderly ALF-exposed Mtb had reduced control and fewer phagosome-lysosome fusion events, which was reversed when elderly ALF was replenished with functional SP-A/SP-D. In vivo, exposure to elderly ALF exacerbated Mtb infection in young mice. Our studies demonstrate how the pulmonary environment changes as we age and suggest that Mtb may benefit from declining host defenses in the lung mucosa of the elderly.

High-Temperature Refractory Metasurfaces for Solar Thermophotovoltaic Energy Harvesting.

Solar energy promises a viable solution to meet the ever-increasing power demand by providing a clean, renewable energy alternative to fossil fuels. For solar thermophotovoltaics (STPV), high-temperature absorbers and emitters with strong spectral selectivity are imperative to efficiently couple solar radiation into photovoltaic cells. Here, we demonstrate refractory metasurfaces for STPV with tailored absorptance and emittance characterized by in situ high-temperature measurements, featuring thermal stability up to at least 1200 °C. Our tungsten-based metasurface absorbers have close-to-unity absorption from visible to near-infrared and strongly suppressed emission at longer wavelengths, while our metasurface emitters provide wavelength-selective emission spectrally matched to the band-edge of InGaAsSb photovoltaic cells. The projected overall STPV efficiency is as high as 18% when a fully integrated absorber/emitter metasurface structure is employed, which is comparable to the efficiencies of the best currently available commercial single-junction PV cells and can be further improved to potentially exceed those in mainstream photovoltaic technologies. Our work opens a path forward for high-performance STPV systems based on refractory metasurface structures.

RUNX3 Promotes the Tumorigenic Phenotype in KGN, a Human Granulosa Cell Tumor-Derived Cell Line.

Granulosa cell tumors of the ovary (GCT) are the predominant type of ovarian sex cord/stromal tumor. Although prognosis is generally favorable, the outcome for advanced and recurrent GCT is poor. A better understanding of the molecular pathogenesis of GCT is critical to developing effective therapeutic strategies. Here we have examined the potential role of the runt-related transcription factor RUNX3. There are only two GCT cell lines available. While RUNX3 is silenced in the GCT cell line KGN cells, it is highly expressed in another GCT cell line, COV434 cells. Re-expression of RUNX3 promotes proliferation, anchorage-independent growth, and motility in KGN cells in vitro and tumor formation in mice in vivo. Furthermore, expression of a dominant negative form of RUNX3 decreases proliferation of COV434 cells. To address a potential mechanism of action, we examined expression of cyclin D2 and the CDK inhibitor p27Kip1, two cell cycle regulators known to be critical determinants of GCT cell proliferation. We found that RUNX3 upregulates the expression of cyclin D2 at the mRNA and protein level, and decreases the level of the p27Kip1 protein, but not p27Kip1 mRNA. In conclusion, we demonstrate that RUNX proteins are expressed in GCT cell lines and human GCT specimens, albeit at variable levels, and RUNX3 may play an oncogenic role in a subset of GCTs.

FGD5 Regulates VEGF Receptor-2 Coupling to PI3 Kinase and Receptor Recycling.

OBJECTIVE: VEGF (vascular endothelial growth factor-A) signaling to the endothelial cell (EC) through VEGFR2 (VEGF receptor-2) is the principal cue driving new blood vessel formation. FGD5 (faciogenital dysplasia-5)-a Rho-family guanine nucleotide exchange factor-is selectively expressed in EC. Deficiency of FGD5 is embryonically lethal in mice and perturbs angiogenesis and VEGF signal transduction. However, the mechanism of FGD5 regulation of VEGF signaling is poorly understood. APPROACH AND RESULTS: Angiogenic sprouting and EC cytoskeletal remodeling were evaluated in a 3-dimensional in vitro model. We examined the subcellular localization of FGD5 and VEGFR2 in EC by immunofluorescent staining and studied the association by immunoprecipitation. FGD5 deficiency reduced the number of angiogenic sprouts and tip cell filopodia by ≈80% and ≈70%, respectively. These defects were accompanied by downregulation of the expression of tip cell-specific markers. FGD5 inactivation led to a decrease in EC migration and early protrusion (lamellipodia) formation. In resting and VEGF-stimulated EC, FGD5 forms a complex with VEGFR2 and was enriched at the leading edge of the cell and among endosomes. FGD5 loss reduced mTORC2 (mammalian target of rapamycin complex-2)/Akt-dependent cortactin activation downstream of VEGFR2 but did not alter VEGFR2 plasma membrane expression, Y1175 phosphorylation, or endocytosis. However, FGD5 loss decreased endosomal VEGFR2 coupling to phosphoinositide-3 kinase and diverted VEGFR2 to lysosomal degradation. CONCLUSIONS: FGD5 regulates VEGFR2 retention in recycling endosomes and coupling to PI3 (phosphoinositide-3) kinase/mTORC2-dependent cytoskeletal remodeling.

γ-Tilmanocept, a New Radiopharmaceutical Tracer for Cancer Sentinel Lymph Nodes, Binds to the Mannose Receptor (CD206).

γ-Tilmanocept ((99m)Tc-labeled-tilmanocept or [(99m)Tc]-tilmanocept) is the first mannose-containing, receptor-directed, radiolabeled tracer for the highly sensitive imaging of sentinel lymph nodes in solid tumor staging. To elucidate the mannose-binding receptor that retains tilmanocept in this microenvironment, human macrophages were used that have high expression of the C-type lectin mannose receptor (MR; CD206). Cy3-labeled tilmanocept exhibited high specificity binding to macrophages that was nearly abolished in competitive inhibition experiments. Furthermore, Cy3-tilmanocept binding was markedly reduced on macrophages deficient in the MR by small interfering RNA treatment and was increased on MR-transfected HEK 293 cells. Finally, confocal microscopy revealed colocalization of Cy3-tilmanocept with the macrophage membrane MR and binding of labeled tilmanocept to MR(+) cells (macrophages and/or dendritic cells) in human sentinel lymph node tissues. Together these data provide strong evidence that CD206 is a major binding receptor for γ-tilmanocept. Identification of CD206 as the γ-tilmanocept-binding receptor enables opportunities for designing receptor-targeted advanced imaging agents and therapeutics for cancer and other diseases.

Conducting Interface in Oxide Homojunction: Understanding of Superior Properties in Black TiO2.

Black TiO2 nanoparticles with a crystalline core and amorphous-shell structure exhibit superior optoelectronic properties in comparison with pristine TiO2. The fundamental mechanisms underlying these enhancements, however, remain unclear, largely due to the inherent complexities and limitations of powder materials. Here, we fabricate TiO2 homojunction films consisting of an oxygen-deficient amorphous layer on top of a highly crystalline layer, to simulate the structural/functional configuration of black TiO2 nanoparticles. Metallic conduction is achieved at the crystalline-amorphous homointerface via electronic interface reconstruction, which we show to be the main reason for the enhanced electron transport of black TiO2. This work not only achieves an unprecedented understanding of black TiO2 but also provides a new perspective for investigating carrier generation and transport behavior at oxide interfaces, which are of tremendous fundamental and technological interest.

Elemental Ingredients in the Macrophage Cocktail: Role of ZIP8 in Host Response to Mycobacterium tuberculosis.

Tuberculosis (TB) is a global epidemic caused by the infection of human macrophages with the world's most deadly single bacterial pathogen, Mycobacterium tuberculosis (M.tb). M.tb resides in a phagosomal niche within macrophages, where trace element concentrations impact the immune response, bacterial metal metabolism, and bacterial survival. The manipulation of micronutrients is a critical mechanism of host defense against infection. In particular, the human zinc transporter Zrt-/Irt-like protein 8 (ZIP8), one of 14 ZIP family members, is important in the flux of divalent cations, including zinc, into the cytoplasm of macrophages. It also has been observed to exist on the membrane of cellular organelles, where it can serve as an efflux pump that transports zinc into the cytosol. ZIP8 is highly inducible in response to M.tb infection of macrophages, and we have observed its localization to the M.tb phagosome. The expression, localization, and function of ZIP8 and other divalent cation transporters within macrophages have important implications for TB prevention and dissemination and warrant further study. In particular, given the importance of zinc as an essential nutrient required for humans and M.tb, it is not yet clear whether ZIP-guided zinc transport serves as a host protective factor or, rather, is targeted by M.tb to enable its phagosomal survival.

Keratinocyte growth factor administration attenuates murine pulmonary mycobacterium tuberculosis infection through granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent macrophage activation and phagolysosome fusion.

Augmentation of innate immune defenses is an appealing adjunctive strategy for treatment of pulmonary Mycobacterium tuberculosis infections, especially those caused by drug-resistant strains. The effect of intranasal administration of keratinocyte growth factor (KGF), an epithelial mitogen and differentiation factor, on M. tuberculosis infection in mice was tested in prophylaxis, treatment, and rescue scenarios. Infection of C57BL6 mice with M. tuberculosis resulted in inoculum size-dependent weight loss and mortality. A single dose of KGF given 1 day prior to infection with 10(5) M. tuberculosis bacilli prevented weight loss and enhanced pulmonary mycobacterial clearance (compared with saline-pretreated mice) for up to 28 days. Similar effects were seen when KGF was delivered intranasally every third day for 15 days, but weight loss and bacillary growth resumed when KGF was withdrawn. For mice with a well established M. tuberculosis infection, KGF given every 3 days beginning on day 15 postinoculation was associated with reversal of weight loss and an increase in M. tuberculosis clearance. In in vitro co-culture experiments, M. tuberculosis-infected macrophages exposed to conditioned medium from KGF-treated alveolar type II cell (MLE-15) monolayers exhibited enhanced GM-CSF-dependent killing through mechanisms that included promotion of phagolysosome fusion and induction of nitric oxide. Alveolar macrophages from KGF-treated mice also exhibited enhanced GM-CSF-dependent phagolysosomal fusion. These results provide evidence that administration of KGF promotes M. tuberculosis clearance through GM-CSF-dependent mechanisms and enhances host defense against M. tuberculosis infection.

Frequency-agile electromagnetically induced transparency analogue in terahertz metamaterials.

Recently reported active metamaterial analogues of electromagnetically induced transparency (EIT) are promising in developing novel optical components, such as active slow light devices. However, most of the previous works have focused on manipulating the EIT resonance strength at a fixed characteristic frequency and, therefore, realized on-to-off switching responses. To further extend the functionalities of the EIT effect, here we present a frequency tunable EIT analogue in the terahertz regime by integrating photoactive silicon into the metamaterial unit cell. A tuning range from 0.82 to 0.74 THz for the EIT resonance frequency is experimentally observed by optical pump-terahertz probe measurements, allowing a frequency tunable group delay of the terahertz pulses. This straightforward approach delivers frequency agility of the EIT resonance and may enable novel ultrafast tunable devices for integrated plasmonic circuits.

RUNX3 contributes to carboplatin resistance in epithelial ovarian cancer cells.

OBJECTIVE: Resistance to platinum-based therapeutic agents represents a major hurdle in the treatment of epithelial ovarian cancer (EOC). There is an urgent need to better understand the underlying mechanisms. Here, we investigated the role of RUNX3 in carboplatin resistance in EOC cells. METHODS: Expression of RUNX3 was determined in human EOC cell line A2780s (cisplatin-sensitive) and A2780cp (cisplatin-resistant), human ovarian surface epithelium (OSE) and primary EOC cells. The effects of RUNX3 expression on sensitivity to carboplatin were determined in A2780s and A2780cp cells using neutral red uptake and clonogenic assays. Carboplatin-induced apoptosis was determined by measuring cleaved PARP using Western blotting. The expression of cellular inhibitor of apoptosis protein-2 (cIAP2) and its regulation by RUNX3 were assessed by quantitative RT-PCR and Western blotting. RESULTS: The expression of RUNX3 was elevated in A2780cp cells compared to A2780s cells and in EOC tissues from chemoresistant patients compared to those from chemosensitive patients. Overexpression of RUNX3 rendered A2780s cells more resistant to carboplatin, whereas inhibition of RUNX3 increased sensitivity to carboplatin in A2780cp cells. Inhibition of RUNX3 potentiated carboplatin-induced apoptosis in A2780cp cells as demonstrated by more pronounced PARP cleavage. Interestingly, the expression of cIAP2 was elevated in A2780cp cells compared to A2780s cells. Overexpression of RUNX3 increased cIAP2 expression in A2780s cells, whereas inhibition of RUNX3 decreased cIAP2 expression and potentiated carboplatin-induced decrease of cIAP2 in A2780cp cells. CONCLUSIONS: RUNX3 contributes to carboplatin resistance in EOC cells and may hold promise as a therapeutic target to treat EOC and/or a biomarker to predict chemoresistance.

Design and synthesis of novel anti-tuberculosis agents from the celecoxib pharmacophore.

The identification of compounds with anti-mycobacterial activity within classes of molecules that have been developed for other purposes is a fruitful approach for the development of anti-tuberculosis (TB) agents. In this study we used the scaffold of celecoxib which exhibits several activities against different pathogens, for the design and focused synthesis of a library of 64 compounds. For the primary screen, we used a bioluminescence-based method by constructing a luciferase-expressing reporter M.tb strain which contains the entire bacterial Lux operon cloned in a mycobacterial integrative expression vector. Through the screening of this library, we identified 6 hit compounds with high in vitro anti-mycobacterial activity (IC50 ∼0.18-0.48 µM). In particular, compounds 41, 51 and 53 were capable of inhibiting M.tb as effectively as the anti-TB drug isoniazid (INH) at 5 µM over a 72-h period, as analyzed by both bioluminescence- and colony forming unit (CFU)-based assays. All hit compounds also showed anti-M.tb activities against several multi-drug-resistant (MDR) strains. Most of the hit compounds showed no cytotoxicity for human macrophages at concentrations as high as 40 µM, setting the stage for further optimization and development of these anti-TB hit compounds both ex vivo and in vivo.