Anisotropic NMR data acquisition with a prototype 400 MHz cryogen-free NMR spectrometer.

High-temperature superconducting (HTS) materials have recently been incorporated into the construction of HTS cryogen-free magnets for nuclear magnetic resonance (NMR) spectroscopy. These HTS NMR spectrometers do not require liquid cryogens, thereby providing significant cost savings and facilitating easy integration into chemistry laboratories. However, the optimal performance of these HTS magnets against standard cryogen NMR magnets must be evaluated, especially with demanding modern NMR applications such as NMR in anisotropic media. The stability of the HTS magnets over time and their performance with complex pulse sequence experiments are the main unknown factors of this new technology. In this study, we evaluate the utility of our prototype 400 MHz cryogen-free power-driven HTS NMR spectrometer, installed in the fumehood of a chemistry laboratory, for stereochemical analysis of three commercial natural products (artemisinin, artemether, and dihydroartemisinin) via measurement of anisotropic NMR data, in particular, residual dipolar couplings. The accuracy of measurement of the anisotropic NMR data with the HTS magnet spectrometer is evaluated through the CASE-3D fitting protocol, as implemented in the Mestrenova-StereoFitter software program.

Recombinant human Erythropoietin enhanced the cytotoxic effects of tamoxifen toward the spheroid MCF-7 breast cancer cells.

Erythropoietin (EPO) is widely used to treat anemia in patients undergoing chemotherapy for cancers. The main objective of this study was to investigate the effect of rHuEPO on the response of spheroid breast cancer, MCF-7, cells to tamoxifen treatment. The MCF-7 spheroids were treated with 10 mg/mL tamoxifen in combination with either 0, 10, 100 or 200 IU/mL rHuEPO for 24, 48 or 72 h. The viability of the MCF-7 cells was determined using the annexin-V, cell cycle, caspases activation and acridine orange/propidium iodide staining. rHuEPO-tamoxifen combination significantly (p greater than 0.05) increased the number of spheroid MCF-7 cells entering early apoptotic phase after 12 h and late apoptotic phase after 24 h of treatment; primarily the result of the antiproliferative effect tamoxifen. Tamoxifen alone significantly (p < 0.05) increased the caspase-3 and -9 activities in the spheroid MCF-7 cells by 200 to 550% of the control. Combination rHuEPO and tamoxifen produced much lesser effect on the caspase-8 activity. The rHuEPO in the combination treatment had concentration-dependently caused decrease in the caspase activities. rHuEPO-tamoxifen combination markedly increased MCF-7 cells entering the SubG0/G1 phase of the cell cycle by more than 500% of the control, while decreasing those entering the G2 + M and S phases by 50%. After 72 h, the combination treatment produced greater (p < 0.05) change in the SubG0/G1 phase than tamoxifen treatment alone. Morphologically, spheroid MCF-7 cells subjected to combination rHuEPO-tamoxifen treatment showed nuclear condensation and margination, cytoplasmic blebbing, necrosis, and early and late apoptosis. Thus, the study showed that rHuEPO-tamoxifen combination induced apoptosis in the spheroid MCF-7 cells. The apoptotic effect of the rHuEPO-tamoxifen combination treatment on the MCF-7 cells was greater than that produced by tamoxifen alone. The rHuEPO-tamoxifen treatment enhanced the caspase-independent apoptotic effects of tamoxifen on the spheroid MCF-7 cells.

A Novel Approach to Increase the Oxygen Permeability of Soft Contact Lenses by Incorporating Silica Sol.

This study presents a novel approach to increase the oxygen permeability of hydrogel by the addition of silica sol. Herein, 2-hydroxyethyl methacrylate (HEMA) was copolymerized with N-vinyl-2-pyrrolidone (NVP) after mixing with silica sol. The resultant hydrogel was subject to characterizations including Fourier-transform infrared (FTIR), equilibrium water content (EWC), contact angle, optical transmittance, oxygen permeability (Dk), tensile test, anti-deposition of proteins, and cytotoxicity. The results showed that with the increase of silica content, the Dk values and Young's moduli increased, the optical transmittance decreased slightly, whereas the EWC and contact angle, and protein deposition were not much affected. Moreover, the cytotoxicity of the resultant poly(HEMA-co-NVP)-SNPs indicated that the presence of silica sol was non-toxic and caused no effect to the growth of L929 cells. Thus, this approach increased the Dk of soft contact lenses without affecting their hydrophilicity.

Spermine synthesis inhibitor blocks 25-hydroxycholesterol-induced- apoptosis via SREBP2 upregulation in DLD-1 cell spheroids.

The oxysterol 25-hydroxycholesterol (25-HC) has diverse physiological activities, including the ability to inhibit anchorage-independent growth of colorectal cancer cells. Here, we found that a polyamine synthesis inhibitor, DFMO, prevented 25-HC-induced apoptosis in non-anchored colorectal cancer DLD-1 cells. Additionally, we found that the spermine synthesis inhibitor APCHA also inhibited 25-HC-induced apoptosis in DLD-1 spheroids. Inhibiting the maturation of SREBP2, a critical regulator of cholesterol synthesis, reversed the effects of APCHA. SREBP2 knockdown also abolished the ability of APCHA to counteract 25-HC activity. Furthermore, APCHA induced SREBP2 maturation and upregulated its transcriptional activity, indicating that altered polyamine metabolism can increase SREBP2 activity and block 25-HC-induced apoptosis in spheroids. These results suggest that crosstalk between polyamine metabolism and cholesterol synthetic pathways via SREBP2 governs the proliferative and malignant properties of colorectal cancer cells.

PEP06 polypeptide 30 is a novel cluster-dissociating agent inhibiting α v integrin/FAK/Src signaling in oral squamous cell carcinoma cells.

Collectively migrating tumor cells have been recently implicated in enhanced metastasis of epithelial malignancies. In oral squamous cell carcinoma (OSCC), αv integrin is a crucial mediator of multicellular clustering and collective movement in vitro; however, its contribution to metastatic spread remains to be addressed. According to the emerging therapeutic concept, dissociation of tumor clusters into single cells could significantly suppress metastasis-seeding ability of carcinomas. This study aimed to investigate the anti-OSCC potential of novel endostatin-derived polypeptide PEP06 as a cluster-dissociating therapeutic agent in vitro. Firstly, we found marked enrichment of αv integrin in collectively invading multicellular clusters in human OSCCs. Our study revealed that metastatic progression of OSCC was associated with augmented immunostaining of αv integrin in cancerous lesions. Following PEP06 treatment, cell clustering on fibronectin, migration, multicellular aggregation, anchorage-independent survival and colony formation of OSCC were significantly inhibited. Moreover, PEP06 suppressed αv integrin/FAK/Src signaling in OSCC cells. PEP06-induced loss of active Src and E-cadherin from cell-cell contacts contributed to diminished collective migration of OSCC in vitro. Overall, these results suggest that PEP06 polypeptide 30 inhibiting αv integrin/FAK/Src signaling and disrupting E-cadherin-based intercellular junctions possesses anti-metastatic potential in OSCC by acting as a cluster-dissociating therapeutic agent.

Integrin-EGFR interaction regulates anoikis resistance in colon cancer cells.

Anoikis resistance is an essential property of cancer cells that allow the extra-cellular matrix-detached cells to survive in a suspended state in body fluid in order to metastasize and invade to distant organs. It is known that integrins play an important role in anoikis resistance, but detailed mechanisms are not well understood. Here we report that highly metastatic colon cancer cells showed a higher degree of anoikis resistance than the normal intestinal epithelial cells. These anoikis-resistant cancer cells express high-levels of integrin-α2, ß1, and activated EGFR in the anchorage-independent state than the anchorage-dependent state. In contrast, normal intestinal epithelial cells failed to elevate these proteins. Interestingly, a higher co-association of EGFR with integrin-α2ß1/-α5ß1 was observed on the surface of anoikis-resistant cells. Thus, in the absence of extra-cellular matrix, integrins in association with EGFR activates downstream effectors ERK and AKT and suppress Caspase-3 activation to induce anoikis resistance as was confirmed from the gene-ablation and pharmacological inhibitor studies. Interestingly, these anoikis-resistant cancer cells express high-level of cancer stem cell signatures (CD24, CD44, CD133, EpCAM) and pluripotent stem cell markers (OCT-4, SOX-2, Nanog) as well as drug-resistant pumps (ABCG2, MDR1, MRP1). Altogether, our findings unravel the interplay between integrin-α2ß1/-α5ß1 and EGFR in anoikis resistance and suggest that the resistant cells are cancer initiating or cancer stem cells, which may serve as a promising target to combat metastasis of cancer.

Fluorescence Enhancement from Nitro-Compound-Sensitive Bacteria within Spherical Hydrogel Scaffolds.

For the safety of both production and life, it is a very significant issue to detect explosive nitro compounds in a remote way or over a long distance. Here, we report that nitro compounds were detected by the bacterial sensor based on hydrogel microbeads as a platform. Green fluorescent protein-producing Escherichia coli, which was genetically engineered to be sensitive to nitro compounds, was loaded within poly(2-hydroxyethyl methacrylate) [poly(HEMA)]-based hydrogel beads, in which fluorescent signals from bacteria were concentrated and strong enough to be easily detected. For efficient loading of negatively charged bacteria, the surface charge of poly(HEMA)-based beads was controlled by copolymerization with 2-(methacryloyloxy)ethyltrimethylammonium chloride (MAETC) as a cationic monomer. With the addition of MAETC, the cell affinity was nine times enhanced by the interaction between the positively charged poly(HEMA- co-MAETC) beads and negatively charged bacteria. The increased cell affinity resulted in an enhancement of a sensing signal. After exposure to 2,4,6-trinitrotoluene, a typical explosive nitro compound, the fluorescence intensity of bacterial sensors using poly(HEMA- co-MAETC) beads having 80 wt % MAETC was five times increased compared to those based on poly(HEMA) beads. This amplification of the fluorescent signal enables easier detection of explosives efficiently by a remote detection, even over a long distance.

Formation of Stem Cell Aggregates and Their Differentiation on Surface-Patterned Hydrogels Based on Poly(2-hydroxyethyl Methacrylate).

Micropillar patterns were fabricated and used to study cell adhesion, morphology, and function. Micropillars were produced in poly(2-hydroxyethyl methacrylate (HEMA)/N,N-(dimethylaminoethyl)methacrylate (DMAEMA)/tetraethylene glycol dimethacrylate (TEGDMA)) hydrogels using soft lithography, had dimensions of 1 µm diameter, and were either 2.05 or 4.91 µm tall. The patterned hydrogel substrates increased adhesion and induced the formation of cellular aggregates. Digital micrographs were used to quantify aggregate size and number. Differentiation of hMSCs toward adipocytes and chondrocytes was performed using the respective complete culture and differentiation medium for 2 weeks. Cells were stained for Oil red O, Alcian blue, and Type II collagen. Hydrogel substrates supported the differentiation of hMSCs to adipocytes and chondrocytes. The taller micropillar patterns supported the attachment and growth of larger aggregates and were more amenable to aid chondrogenic differentiation.

Three-Dimensional Spheroid Culture Increases Exosome Secretion from Mesenchymal Stem Cells.

BACKGROUND: Mass production of exosomes is a prerequisite for their commercial utilization. This study investigated whether three-dimensional (3D) spheroid culture of mesenchymal stem cells (MSCs) could improve the production efficiency of exosomes and if so, what was the mechanism involved. METHODS: We adopted two models of 3D spheroid culture using the hanging-drop (3D-HD) and poly(2-hydroxyethyl methacrylate) (poly-HEMA) coating methods (3D-PH). The efficiency of exosome production from MSCs in the 3D spheroids was compared with that of monolayer culture in various conditions. We then investigated the mechanism of the 3D spheroid culture-induced increase in exosome production. RESULTS: The 3D-HD formed a single larger spheroid, while the 3D-PH formed multiple smaller ones. However, MSCs cultured on both types of spheroids produced significantly more exosomes than those cultured in conventional monolayer culture (2D). We then investigated the cause of the increased exosome production in terms of hypoxia within the 3D spheroids, high cell density, and non-adherent cell morphology. With increasing spheroid size, the efficiency of exosome production was the largest with the least amount of cells in both 3D-HD and 3D-PH. An increase in cell density in 2D culture (2D-H) was less efficient in exosome production than the conventional, lower cell density, 2D culture. Finally, when cells were plated at normal density on the poly-HEMA coated spheroids (3D-N-PH); they formed small aggregates of less than 10 cells and still produced more exosomes than those in the 2D culture when plated at the same density. We also found that the expression of F-actin was markedly reduced in the 3D-N-PH culture. CONCLUSION: These results suggested that 3D spheroid culture produces more exosomes than 2D culture and the non-adherent round cell morphology itself might be a causative factor. The result of the present study could provide useful information to develop an optimal process for the mass production of exosomes.

Development of Poly(HEMA-Am) Polymer Hydrogel Filler for Soft Tissue Reconstruction by Facile Polymerization.

The number of breast reconstruction surgeries has been increasing due to the increase in mastectomies. Surgical implants (the standard polydimethylsiloxane (PDMS) implants) are widely used to reconstruct breast tissues, however, it can cause problems such as adverse immune reactions, fibrosis, rupture, and additional surgery. Hence, polymeric fillers have recently garnered increasing attention as strong alternatives for breast reconstruction materials. Polymeric fillers offer noninvasive methods of reconstruction, thereby reducing the possible adverse effects and simplifying the treatment. In this study, we synthesized a 2-hydroxylethylmethacrylate (HEMA) and acrylamide (Am) copolymer (Poly(HEMA-Am)) by redox polymerization to be used as a biocompatible filler material for breast reconstruction. The synthesized hydrogel swelled in phosphate buffered saline (PBS) shows an average modulus of 50 Pa, which is a characteristic similar to that of the standard dermal acrylamide filler. To investigate the biocompatibility and cytotoxicity of the Poly(HEMA-Am) hydrogel, we evaluated an in vitro cytotoxicity assay on human fibroblasts (hFBs) and human adipose-derived stem cells (hADSCs) with the hydrogel eluate, and confirmed a cell viability of over 80% of the cell viability with the Poly(HEMA-Am) hydrogel. These results suggest our polymeric hydrogel is a promising filler material in soft tissue augmentation including breast reconstruction.

Three-Dimensional Spheroid Culture Increases Exosome Secretion from Mesenchymal Stem Cells

BACKGROUND: Mass production of exosomes is a prerequisite for their commercial utilization. This study investigated whether three-dimensional (3D) spheroid culture of mesenchymal stem cells (MSCs) could improve the production efficiency of exosomes and if so, what was the mechanism involved. METHODS: We adopted two models of 3D spheroid culture using the hanging-drop (3D-HD) and poly(2-hydroxyethyl methacrylate) (poly-HEMA) coating methods (3D-PH). The efficiency of exosome production from MSCs in the 3D spheroids was compared with that of monolayer culture in various conditions. We then investigated the mechanism of the 3D spheroid culture-induced increase in exosome production. RESULTS: The 3D-HD formed a single larger spheroid, while the 3D-PH formed multiple smaller ones. However, MSCs cultured on both types of spheroids produced significantly more exosomes than those cultured in conventional monolayer culture (2D). We then investigated the cause of the increased exosome production in terms of hypoxia within the 3D spheroids, high cell density, and non-adherent cell morphology. With increasing spheroid size, the efficiency of exosome production was the largest with the least amount of cells in both 3D-HD and 3D-PH. An increase in cell density in 2D culture (2D-H) was less efficient in exosome production than the conventional, lower cell density, 2D culture. Finally, when cells were plated at normal density on the poly-HEMA coated spheroids (3D-N-PH); they formed small aggregates of less than 10 cells and still produced more exosomes than those in the 2D culture when plated at the same density. We also found that the expression of F-actin was markedly reduced in the 3D-N-PH culture. CONCLUSION: These results suggested that 3D spheroid culture produces more exosomes than 2D culture and the non-adherent round cell morphology itself might be a causative factor. The result of the present study could provide useful information to develop an optimal process for the mass production of exosomes.

A poly(2-hydroxyethyl methacrylate)-based resin improves the dentin remineralizing ability of calcium silicates.

Bioactive polymeric composites have received great attention for their capability to remineralize the dentin tissue. This study was aimed at evaluating if a poly(HEMA-co-TEGDMA) resin (HEMA: 2-hydroxyethyl methacrylate; TEGDMA: triethyleneglycol dimethacrylate) may increase the in vitro apatite forming ability of a calcium silicate cement (CaSi), in view of developing a hydrophilic light-curable composite bio-remineralizing restorative material (R-CaSi). To this purpose, the following experiments were carried out: (1) In vitro apatite forming ability of R-CaSi and CaSi was comparatively assessed by micro-Raman spectroscopy after immersion of the cement disks in Dulbecco's Phosphate Buffered Saline (DPBS) at 37°C for 1-28days; (2) Previously demineralized human dentin slices were soaked for 7days in close contact with the CaSi and R-CaSi cements as well as poly(HEMA), poly(TEGDMA) and poly(HEMA-co-TEGDMA), and then were comparatively analyzed by IR spectroscopy. Micro-Raman spectroscopy showed that in calcium phosphate nucleation tests, the B-type carbonated apatite deposit formed on R-CaSi was thicker than that on CaSi; therefore, the poly(HEMA-co-TEGDMA) resin proved able to increase the in vitro apatite forming ability of the calcium silicate-based cement. Both cements were found to induce dentin remineralization, R-CaSi to a higher extent, in agreement with the calcium phosphate nucleation tests. This result may be ascribed to the positive role played by the polymeric component, which was found to interact with collagen and to chelate calcium ions. Upon remineralization, collagen underwent conformational rearrangements and the formed apatite phase, rather than a simple deposit, was intimately bound to the collagen matrix, thanks to the calcium ions chelated by it.

Adhesion attenuates respiratory burst induced by different modes of triggering in resting or LPS-primed neutrophils.

The effects of adherence on neutrophil superoxide anion (O2-) generation triggered by surface, soluble ligand, or adherence were studied. Resting-neutrophils adhered to the uncoated tubes resulting in O2- generation, but not on plasma-, fibrinogen-, vitronectin-, fibronectin-, laminin-, collagen-, or poly HEMA-coated surfaces. Enhanced N-formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated O2- generation by LPS-primed-neutrophils was induced by the incubation on plasma, fibrinogen, vitronectin, fibronectin, or laminin in the absence of Mg2+. In the presence of Mg2+, this response was observed in cells on collagen or poly HEMA. LPS-primed-neutrophils adhered to uncoated, BSA- or IgG-coated tubes and did not respond to fMLP, indicating that the fMLP-response of LPS-primed-neutrophils was suppressed by adherence. Upon incubation on plasma, fibrinogen, vitronectin, fibronectin in the presence of Mg2+, LPS-primed-neutrophils showed O2- generation. Upon incubation on collagen or poly HEMA, the primed-neutrophils neither generated O2- nor adhered. We found that O2- response of LPS-primed-neutrophils was attenuated depending on the time of exposure to plasma-coated surface. This attenuation was evident on plasma or fibrinogen, but not on collagen in the presence of Mg2+, indicating that O2- generation by LPS-primed-neutrophils was attenuated dependent on adherence but not on Mg2+. Thus, adhesion attenuated the O2- generation triggered by both soluble (fMLP) and insoluble (surface) stimuli.

Controlled release of curcumin from poly(HEMA-MAPA) membrane.

In this work, poly(HEMA-MAPA) membranes were prepared by UV-polymerization technique. These membranes were characterized by SEM, FTIR, and swelling studies. Synthesized membranes had high porous structure. These membranes were used for controlled release of curcumin which is already used as folk remedy and used as drug for some certain diseases and cancers. Curcumin release was investigated for various pHs and temperatures. Optimum drug release yield was found to be as 70% at pH 7.4 and 37 °C within 2 h period. Time-depended release of curcumin was also investigated and its slow release from the membrane demonstrated within 48 h.

Preparation of three-dimensional macroporous chitosan-gelatin B microspheres and HepG2-cell culture.

Chitosan-gelatin B microspheres with an open, interconnected, highly macroporous (100-200 µm) structure were prepared via a three-step protocol combining freeze-drying with an electrostatic and ionic cross-linking method. Saturated tripolyphosphate ethanol solution (85% ethanol) was chosen as the crosslinking agent to prevent destruction of the porous structure and to improve the biostability of the chitosan-gelatin B microspheres, with N-(3-dimethylaminopropyl)-N'-ethyl-carbodiimide/N-hydroxysuccinimide as a second crosslinking agent to react with gelatin A and fixed chitosan-gelatin B microspheres to attain improved biocompatibility. Water absorption of the three-dimensional macroporous chitosan-gelatin B microspheres (3D-P-CGMs) was 12.84, with a porosity of 85.45%. In vitro lysozyme degradation after 1, 3, 5, 7, 10, 14, and 21 days showed improved biodegradation in the 3D-P-CGMs. The morphology of human hepatoma cell lines (HepG2 cells) cultured on the 3D-P-CGMs was spherical, unlike that of cells cultured under traditional two-dimensional conditions. Scanning electron microscopy and paraffin sections were used to confirm the porous structure of the 3D-P-CGMs. HepG2 cells were able to migrate inside through the pore. Cell proliferation and levels of albumin and lactate dehydrogenase suggested that the 3D-P-CGMs could provide a larger specific surface area and an appropriate microenvironment for cell growth and survival. Hence, the 3D-P-CGMs are eminently suitable as macroporous scaffolds for cell cultures in tissue engineering and cell carrier studies. Copyright © 2014 John Wiley & Sons, Ltd.

Nuclear localized Akt enhances breast cancer stem-like cells through counter-regulation of p21(Waf1/Cip1) and p27(kip1).

UNLABELLED: Cancer stem-like cells (CSCs) are a rare subpopulation of cancer cells capable of propagating the disease and causing cancer recurrence. In this study, we found that the cellular localization of PKB/Akt kinase affects the maintenance of CSCs. When Akt tagged with nuclear localization signal (Akt-NLS) was overexpressed in SKBR3 and MDA-MB468 cells, these cells showed a 10-15% increase in the number of cells with CSCs enhanced ALDH activity and demonstrated a CD44(+High)/CD24(-Low) phenotype. This effect was completely reversed in the presence of Akt-specific inhibitor, triciribine. Furthermore, cells overexpressing Akt or Akt-NLS were less likely to be in G0/G1 phase of the cell cycle by inactivating p21(Waf1/Cip1) and exhibited increased clonogenicity and proliferation as assayed by colony-forming assay (mammosphere formation). Thus, our data emphasize the importance the intracellular localization of Akt has on stemness in human breast cancer cells. It also indicates a new robust way for improving the enrichment and culture of CSCs for experimental purposes. Hence, it allows for the development of simpler protocols to study stemness, clonogenic potency, and screening of new chemotherapeutic agents that preferentially target cancer stem cells. SUMMARY: The presented data, (i) shows new, stemness-promoting role of nuclear Akt/PKB kinase, (ii) it underlines the effects of nuclear Akt on cell cycle regulation, and finally (iii) it suggests new ways to study cancer stem-like cells.

Radiolabeling of new generation magnetic poly(HEMA-MAPA) nanoparticles with (131) I and preliminary investigation of its radiopharmaceutical potential using albino Wistar rats.

In this study, N-methacryloyl-l-phenylalanine (MAPA) containing poly(2-hydroxyethylmethacrylate) (HEMA)-based magnetic poly(HEMA-MAPA) nanobeads [mag-poly(HEMA-MAPA)] were radiolabeled with (131) I [(131) I-mag-poly(HEMA-MAPA)], and the radiopharmaceutical potential of (131) I-mag-poly(HEMA-MAPA) was investigated. Quality control studies were carried out by radiochromatographic method to be sure that (131) I binded to mag-poly(HEMA-MAPA) efficiently. In this sense, binding yield of (131) I-mag-poly(HEMA-MAPA) was found to be about 95-100%. In addition to this, optimum radiodination conditions for (131) I-mag-poly(HEMA-MAPA) were determined by thin-layer radiochromatography studies. In addition to thin-layer radiochromatography studies, lipophilicity (partition coefficient) and stability studies for (131) I-mag-poly(HEMA-MAPA) were realized. It was determined that lipophilicities of mag-poly(HEMA-MAPA) and (131) I-mag-poly(HEMA-MAPA) were 0.12 ± 0.01 and 1.79 ± 0.76 according to ACD/logP algorithm program, respectively. Stability of the radiolabeled compound was investigated in time intervals given as 0, 30, 60, 180, and 1440 min. It was found that (131) I-mag-poly(HEMA-MAPA) existed as a stable complex in rat serum within 60 min. After that, biodistribution and scintigraphy studies were carried out by using albino Wistar rats. It was determined that the most important (131) I activity uptake was observed in the breast, the ovary, and the pancreas. Scintigraphy studies well supported biodistribution results.

Synthesis and applications of poly(2-hydroxyethylmethacrylate) grafted agar: a microwave based approach.

Synthesis of graft copolymers under the influence of microwave radiation alone is a rapid, efficient, clean, cheap, convenient, energy-saving and green method. Grafting of poly(2-hydroxyethylmethacrylate) on agar backbone was carried out under the influence of microwave radiation. The synthesis is optimized in terms of percentage grafting and intrinsic viscosity, by varying the microwave irradiation time and monomer (2-hydroxyethylmethacrylate) concentration. The synthesized graft copolymers have been characterized by intrinsic viscosity measurement, FTIR spectroscopy, UV-spectroscopy, elemental analysis (C, H, N, & S), thermal studies and scanning electron microscopy (SEM). Flocculation efficacy of the synthesized graft copolymers was studied in 0.25% kaolin and 1% coal fine suspension, through 'jar test' procedure. Further, flocculation efficacy of the best grade, coagulant (alum) and agar were studied for possible application in remediation of metals from river water.

Ephexin4-mediated promotion of cell migration and anoikis resistance is regulated by serine 897 phosphorylation of EphA2.

EphA2 is activated through phosphorylation on serine 897 (S897) by Akt to promote cancer cell motility and invasion, independently of stimulation by ephrin, its ligand. Here we show that S897 phosphorylation of EphA2 strengthens the interaction between EphA2 and Ephexin4, a guanine nucleotide exchange factor for the small GTPase RhoG. S897A mutation of EphA2 abolished the EphA2/Ephexin4-mediated RhoG activation, promotion of cell migration, and resistance to anoikis. Our results suggest that S897-phosphorylated EphA2 recruits Ephexin4 to promote cell migration and anoikis resistance, providing a molecular link between S897 phosphorylation of EphA2 and tumor progression.