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New exogenous probes are needed for both imaging diagnostics and therapeutics. Here, we introduce a novel nanocomposite near-infrared (NIR) fluorescent imaging probe and test its potency as a photosensitizing agent for photodynamic therapy (PDT) against triple-negative breast cancer cells. The active component in the nanocomposite is a small molecule, pyropheophorbide a-phosphatidylethanolamine-QSY21 (Pyro-PtdEtn-QSY), which is imbedded into lipid nanoparticles for transport in the body. The probe targets abnormal choline metabolism in cancer cells; specifically, the overexpression of phosphatidylcholine-specific phospholipase C (PC-PLC) in breast, prostate, and ovarian cancers. Pyro-PtdEtn-QSY consists of a NIR fluorophore and a quencher, attached to a PtdEtn moiety. It is selectively activated by PC-PLC resulting in enhanced fluorescence in cancer cells compared to normal cells. In our in vitro investigation, four breast cancer cell lines showed higher probe activation levels than noncancerous control cells, immortalized human mammary gland cells, and normal human T cells. Moreover, the ability of this nanocomposite to function as a sensitizer in PDT experiments on MDA-MB-231 cells suggests that the probe is promising as a theranostic agent.

In this paper, we report the synthesis and characterization of fluorinated derivatives of naphthofluorescein (NF), a fluorescent pH-sensitive probe that can be used for functional Cerenkov imaging. The compounds were prepared using electrophilic fluorination with dilute fluorine gas under acidic conditions. The fluorination of the NF molecule occurred in the ortho positions to the hydroxyl moiety, producing mono-, di-, and tri-substituted derivatives. The properties of the fluorinated naphthofluoresceins were similar to the parent compound, retaining pH sensitivity and fluorescence capability, but showed a more acidic pK(a) with increasing fluorination degree and a bathochromic shift in both absorbance and fluorescence. NF and its two major fluorinated derivatives were shown to attenuate Cerenkov radiation in the basic form; the greatest attenuation was observed at wavelengths coinciding with the absorption maxima. NF also showed potential as a Cerenkov Radiation Energy Transfer (CRET) probe. Fluorinated naphthofluoresceins provide a new family of molecular imaging probes for the detection of pH in tissue and organs by using a combination of PET and Cerenkov imaging.

In the work an eco-friendly non-woven fiber made of polylactide and natural rubber with a rubber content from 0 to 15 wt.% was obtained by electrospinning. The influence of distilled water and UV irradiation on the agrofibers has been investigated. The water sorption test showed that the addition of natural rubber into the polylactide matrix does not significantly affect the degree of water absorption of the fibrous materials, which is in the range of 49-50.6%. Thermal characteristics after 180 days of degradation in distilled water at 22±2 oC and UV irradiation at a wavelength of 365 nm during 100 hours were determined using the differential scanning calorimetry. Changes in the values for glass transition and melting temperatures, and the degree of crystallinity were determined.

Background Myeloperoxidase (MPO) generates hypochlorous acid (HOCl) during inflammation and infection. We showed that secoisolariciresinol diglucoside (SDG) scavenges radiation-induced HOCl in physiological solutions. However, the action of SDG and its synthetic version, LGM2605, on MPO-catalyzed generation of HOCl is unknown. The present study evaluated the effect of LGM2605 on human MPO, and murine MPO from macrophages and neutrophils. Methods MPO activity was determined fluorometrically using hypochlorite-specific 3′-(p-aminophenyl) fluorescein (APF). The effect of LGM2605 on (a) the peroxidase cycle of MPO was determined using Amplex Red while the effect on (b) the chlorination cycle was determined using a taurine chloramine assay. Using electron paramagnetic resonance (EPR) spectroscopy we determined the effect of LGM2605 on the EPR signals of MPO. Finally, computational docking of SDG was used to identify energetically favorable docking poses to enzyme's active site. Results LGM2605 inhibited human and murine MPO activity. MPO inhibition was observed in the absence and presence of Cl−. EPR confirmed that LGM2605 suppressed the formation of Compound I, an oxoiron (IV) intermediate [Fe(IV) O] containing a porphyrin π-radical of MPO's catalytic cycle. Computational docking revealed that SDG can act as an inhibitor by binding to the enzyme's active site. Conclusions We conclude that LGM2605 inhibits MPO activity by suppressing both the peroxidase and chlorination cycles. EPR analysis demonstrated that LGM2605 inhibits MPO by decreasing the formation of the highly oxidative Compound I. This study identifies a novel mechanism of LGM2605 action as an inhibitor of MPO and indicates that LGM2605 may be a promising attenuator of oxidant-dependent inflammatory tissue damage.

Direct electrophilic fluorination using molecular fluorine gas is used in organic synthesis to create novel fluorine-containing compounds with potential beneficial activity that could not be obtained by nucleophilic substitution. In this paper, we report a novel electrophilic substitution of bromine by fluorine in an aromatic system. The mechanism of this type of fluorination was explored using the reaction between bromothymolsulfonphthalein (Bromothymol Blue) and dilute fluorine gas under acidic conditions. Substitution occurs in the bromine atoms located in the ortho-position relative to the hydroxyl group. A similar electrophilic fluorination of thymolsulfonphthalein (Thymol Blue) leads to a substitution of hydrogen atoms in the same position (ortho to hydroxyl). NMR spectroscopy was used to confirm the fluorination sites. NMR spectra of thymolsulfonphthalein and its derivatives under basic conditions can be explained by considering the absence of resonance between the two phenolic rings. Both dibromothymol blue and fluorobromothymol blue intermolecularly attenuate Cerenkov radiation selectively near their maximum absorbance in a pH dependent manner.

Background Radiation exposure of tissues is associated with inflammatory cell influx. Myeloperoxidase (MPO) is an enzyme expressed in granulocytes, such as neutrophils (PMN) and macrophages, responsible for active chlorine species (ACS) generation. The present study aimed to: 1) determine whether exposure to γ-irradiation induces MPO-dependent ACS generation in murine PMN; 2) elucidate the mechanism of radiation-induced ACS generation; and 3) evaluate the effect of the synthetic lignan LGM2605, known for ACS scavenging properties. Methods MPO-dependent ACS generation was determined by using hypochlorite-specific 3′-(p-aminophenyl) fluorescein (APF) and a highly potent MPO inhibitor, 4-aminobenzoic acid hydrazide (ABAH), and confirmed in PMN derived from MPO−/− mice. Radiation-induced MPO activation was determined by EPR spectroscopy and computational analysis identified tyrosine, serine, and threonine residues near MPO's active site. Results γ-radiation increased MPO-dependent ACS generation dose-dependently in human MPO and in wild-type murine PMN, but not in PMN from MPO−/− mice. LGM2605 decreased radiation-induced, MPO-dependent ACS. Protein tyrosine phosphatase (PTP) and protein serine/threonine phosphatase (PSTP) inhibitors decreased the radiation-induced increase in ACS. Peroxidase cycle results demonstrate that tyrosine phosphorylation blocks MPO Compound I formation by preventing catalysis on H2O2 in the active site of MPO. EPR data demonstrate that γ-radiation increased tyrosyl radical species formation in a dose-dependent manner. Conclusions We demonstrate that γ-radiation induces MPO-dependent generation of ACS, which is dependent, at least in part, by protein tyrosine and Ser/Thr dephosphorylation and is reduced by LGM2605. This study identified for the first time a novel protein dephosphorylation-dependent mechanism of radiation-induced MPO activation.

Background Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. Methods The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3′-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3′-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton 1H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO− and radiation. Purine base chlorination by ClO− and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Results: Chloride anions (Cl−) consumed > 90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by 1H NMR. Importantly, SDG scavenged hypochlorite- and γ–radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO− or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO− generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl ) and dichloro radical anions (Cl2¯ )), which were trapped by SDG and its structural analog dopamine. Conclusion We demonstrate that γ-radiation induces the generation of ACS in physiological solutions. SDG treatment scavenged ACS and prevented ACS-induced DNA damage and chlorination of 2-aminopurine. This study identified a novel and unique mechanism of SDG radioprotection, through ACS scavenging, and supports the potential usefulness of SDG as a radioprotector and mitigator for radiation exposure as part of cancer therapy or accidental exposure.

The reversible addition–fragmentation chain transfer (RAFT) of N-vinyl caprolactam (NVCL) using two new xanthates with alkyne functionalities is reported. The kinetic data obtained for polymerization of this non-activated monomer using a protected alkyne-terminated RAFT agent (PAT-X1) revealed a linear increase of the polymer molecular weight with the monomer conversion as well as low dispersity (Đ) during the entire course of the polymerization. The system reported here allowed us to enhance the final conversion, diminish Đ and reduce the polymerization temperature compared to the typical values reported in the scarce literature available for the RAFT polymerization of NVCL. The resulting PNVCL was fully characterized using 1H nuclear magnetic resonance (1H NMR), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), Fourier-transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) techniques. The temperature-responsive features of PNVCL in aqueous solutions were fully investigated under different conditions using turbidimetry. The presented strategy allows the synthesis of well-defined PNVCL with sharp and reversible phase transition temperatures around 37 °C. By manipulating the polymer molecular weight, or the solution properties, it is possible to tune the PNVCL phase transition. As a proof-of concept, the alkyne functionalized PNVCL was used to afford new linear block copolymers, by reacting with an azide-terminated poly(ethylene glycol) (N3-PEG) through the copper catalyzed azide–alkyne [3 + 2] dipolar cycloaddition (CuAAC) reaction. The results presented establish a robust system to afford the synthesis of PNCVL with fine tuned characteristics that will enable more efficient exploration of the remarkable potential of this polymer in biomedical applications.

Cytosolic phospholipase A2α (cPLA2α) has been shown to be elevated in breast cancer and is a potential biomarker in the differentiation of molecular sub-types. Using a cPLA2α activatable fluorophore, DDAO arachidonate, we explore its ability to function as a contrast agent in fluorescence-guided surgery. In cell lines ranging in cPLA2α expression and representing varying breast cancer sub-types, we show DDAO arachidonate activates with a high correlation to cPLA2α expression level. Using a control probe, DDAO palmitate, in addition to cPLA2α inhibition and genetic knockdown, we show that this activation is a result of cPLA2α activity. In mouse models, using an ex vivo tumor painting technique, we show that DDAO arachidonate activates to a high degree in basal-like versus luminal-like breast tumors and healthy mammary tissue. Finally, we show that using an in vivo model, orthotopic basal-like tumors give significantly high probe activation compared to healthy mammary fat pads and surrounding tissue. Together we conclude that cPLA2α activatable fluorophores such as DDAO arachidonate may serve as a useful contrast agent for the visualization of tumor margins in the fluorescence-guided surgery of basal-like breast cancer. © 2019 The Author(s). Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License

The study suggests an application of a coelenteramide-containing fluorescent protein (CLM-CFP) as a simplest bioassay for gamma radiation exposures. “Discharged obelin,” a product of the bioluminescence reaction of the marine coelenterate Obelia longissima, was used as a representative of the CLM-CFP group. The bioassay is based on a simple enzymatic reaction—photochemical proton transfer in the coelenteramide-apoprotein complex. Components of this reaction differ in fluorescence color, providing, by this, an evaluation of the proton transfer efficiency in the photochemical process. This efficiency depends on the microenvironment of the coelenteramide within the protein complex, and, hence, can evaluate a destructive ability of gamma radiation. The CLM-CFP samples were exposed to gamma radiation (137Cs, 2 mGy/h) for 7 and 16 days at 20 °C and 5 °C, respectively. As a result, two fluorescence characteristics (overall fluorescence intensity and contributions of color components to the fluorescence spectra) were identified as bioassay parameters. Both parameters demonstrated high sensitivity of the CLM-CFP-based bioassay to the low-dose gamma radiation exposure (up to 100 mGy). Higher temperature (20 °C) enhanced the response of CLM-CFP to gamma radiation. This new bioassay can provide fluorescent multicolor assessment of protein destruction in cells and physiological liquids under exposure to low doses of gamma radiation.

Activatable fluorophores selective to cytosolic phospholipase A2 (cPLA2) were synthesized and evaluated for their ability to image triple negative breast cancer cells. The activatable constructs were synthesized by esterification of a small molecule fluorophore with a fatty acid resulting in ablated fluorescence. Selectivity for cPLA2 was generated through the choice of fluorophore and fatty acid. Esterification with arachidonic acid was sufficient to impart specificity to cPLA2 when compared to esterification with palmitic acid. In vitro analysis of probes incorporated into phosphatidylcholine liposomes demonstrated that a non-selective phospholipase (sPLA2 group IB) was able to hydrolyze both arachidonate and palmitate coupled fluorophores resulting in the generation of fluorescence. Of the four fluorophores tested, DDAO (7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one)) was observed to perform optimally in vitro and was analyzed further in 4175-Luc+ cells, a metastatic triple negative human breast cancer cell line expressing high levels of cPLA2. In contrast to the in vitro analysis, DDAO arachidonate was shown to activate selectively in 4175-Luc+ cells compared to the control DDAO palmitate as measured by fluorescence microscopy and quantitated with fluorescence spectroscopy. The addition of two agents known to activate cPLA2 enhanced DDAO arachidonate fluorescence without inducing any change to DDAO palmitate. Inhibition of cPLA2 resulted in reduced fluorescence of DDAO arachidonate but not DDAO palmitate. Together, we report the synthesis of a cPLA2 selective activatable fluorophore capable of detecting cPLA2 in triple negative breast cancer cells.

Two new xanthates with alkyne functionalities were synthesized for the reversible addition fragmentation chain transfer (RAFT) polymerization of vinyl acetate (VAc). The new RAFT agents were fully characterized by 1H and 13C NMR spectroscopy. Unlike the alkyne terminated RAFT agent (AT-X1) the protected alkyne-terminated RAFT agent (PAT-X1) was able to conduct the RAFT polymerization of VAc with a good control over the molecular weight (MW) and relatively narrow MW distributions (Đ < 1.4). The linear evolution of Mn with conversion as well as the close agreement between Mn,th and Mn,GPC values confirmed the controlled features of the RAFT system. It is worth mentioning that the polymer dispersity remained very low (Đ < 1.20) until relatively high monomer conversions (60%) due to the non-activated nature of VAc. The chain end-functionality of the obtained polymers was evaluated by 1H NMR, FTIR-ATR and UV-Vis absorption analysis. The “livingness” of the obtained polymer was confirmed by a successful chain extension experiment. The deprotection of the alkyne functionality in the PVAc, allowed a further copper catalyzed azide–alkyne [3 + 2] dipolar cycloaddition reaction (CuAAC) with an azido terminated-poly(ethylene glycol) (PEG-N3), to afford PVAc–PEG block-copolymers as a proof-of-concept.

Novel trifluoromethylated mono- and bicyclic succinimides derived from trifluoromethylmaleic anhydride were synthesized using cyclopentadiene or 2,3-dimethylbutadiene and (het)arylamines. The biological activity of these compounds was evaluated using prediction methods and experimental studies. This series of new trifluoromethyl succinimides (3a,b and 6a-c) were tested by the National Cancer Institute (NCI, Bethesda, USA) by Program NCI-60 DTP Human Tumor Cell Line Screen at a single high dose (10-5 M). Imides revealed activity on Leukemia cell lines (RPMI-8226 - myeloma cell line), Non-Small Cell Lung Cancer cell lines (A549/ATCC - lung carcinoma epithelial cells) and Renal cancer cell lines (A498 and SN12C).

A very fast and controlled atom transfer radical (co)polymerization (ATRP) of acrylates, methacrylates, styrene, and vinyl chloride is reported in a single dipolar aprotic solvent, sulfolane, with the use of ppm amount of the copper catalyst. The observed rates of polymerization (kpapp) of the monomers studied are similar to those reported using dimethyl sulfoxide (DMSO) and other polar solvents typically employed in single electron transfer (SET)-mediated atom transfer radical polymerization (ATRP) processes. As proof-of-concept, ABA type block copolymers of polystyrene-b-poly(vinyl chloride)-b-polystyrene and poly(methyl acrylate)-b-poly(vinyl chloride)-b-poly(methyl acrylate) were prepared for the first time using a reversible deactivation radical polymerization (RDRP) method in a single solvent. The quantitative preservation of halide chain-ends was confirmed by 1H NMR and MALDI-TOF analysis as well as by the complete shift of the GPC traces. The results presented establish an innovative and robust sy...

The reversible addition fragmentation chain transfer (RAFT) of N -(3-aminopropyl)methacrylamide hydrochloride (APMA) using unprotected “clickable” chain transfer agents in water/dioxane mixtures is reported. The controlled character of the polymerization was confirmed by the linear increase of the polymer molecular weight with monomer conversion, the narrow molecular weight distribution ( Ð ⩽ 1.1) and by chain extension experiments. The alkyne-terminated PAPMA was further functionalized by “click” chemistry with an azido-functionalized coumarin derivative. The method reported here will be useful for the preparation of novel PAPMA based materials for biomedical applications using a strategy that does not require challenging protection/deprotection steps.

Activators regeneration by electron transfer atom transfer radical polymerization (ARGET ATRP) of 2-aminoethyl methacrylate hydrochloride (AMA) was successfully performed for the first time. The polymerizations were conducted at 35 °C in isopropanol (IPA)/water mixtures or pure water, using CuBr2/TPMA (TPMA: tris(2-pyridylmethyl)amine) as a metal catalyst complex with slow feeding of ascorbic acid (AscA) to allow regeneration of the activator species. The reactions showed first-order kinetics with monomer conversion and high monomer conversion (>90%), and controlled polymers (Đ ≈ 1.3) were obtained using optimized conditions. For the first time, as a result of the PAMA’s high chain-end functionality, it was possible to extend the polymer and synthesize a well-defined block copolymer (PAMA-b-POEOMA) (OEOMA: oligo(ethylene oxide) methyl ether methacrylate) by ATRP techniques, using AMA as the first block. PAMA-based nanogels, with potential biomedical applications, were prepared by ARGET ATRP in inverse min...

An unusual synergistic effect between 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) and dimethyl sulfoxide (DMSO) mixtures is reported for the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of methyl acrylate (MA) using a catalytic system composed by sodium dithionate (Na2S2O4) and CuBr2/Me6TREN (Me6TREN: tris[2-(dimethylamino)ethyl]amine) at room temperature. To the best of our knowledge, the use of ionic liquids (IL) has never been reported for the SARA ATRP. The kinetic data obtained for a broad range of target molecular weights revealed very fast polymerization rates, low dispersity values (Đ < 1.05) and well-defined chain-end functionalities.

Supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of the cationic monomer (3-acrylamidopropyl)trimethylammonium chloride (AMPTMA) was successfully performed for the first time. The polymerizations were performed in water or ethanol–water mixtures at room temperature in the presence of Cu(0), using relatively low concentrations of soluble copper catalyst and an excess of ligand (Me6TREN). The reaction conditions were optimized to give the best control over the polymerization under environmentally friendly conditions. The polymerization data showed good control over the molecular weights with narrow molecular weight distributions for the entire polymerization. The preservation of the chain-end functionality was confirmed by self-chain extension and the synthesis of a block copolymer containing AMPTMA and oligo(ethylene oxide) methyl ether acrylate (OEOA). SARA ATRP was also extended to the synthesis of alkyne-terminated poly-AMPTMA (PAMPTMA), which was subsequently functionalized, using copper(I) catalyzed azide–alkyne cycloaddition, with an azido-functionalized coumarin derivative.

The kinetics and detailed mechanism of SARA ATRP of 2-(diisopropylamino)ethyl methacrylate (DPA) were investigated. Supplemental activator and reducing agent (SARA) atom transfer radical polymerization (ATRP) using sodium dithionite (Na2S2O4) was used to create well controlled polymers of PDPA. The influence of the initiator, solvent, structure and concentration of the catalyst was studied, and the ratios of Na2S2O4 were adjusted to optimize the polymerization. Well controlled polymers required Na2S2O4 to be slowly and continuously fed to the reaction mixture, with 500 parts per million (ppm) of CuBr2 with tris(2-dimethyamino)amine (Me6TREN) as a ligand. The initial content of Na2S2O4 in the reaction mixture, the feeding rate and the Cu catalyst concentration were optimized to provide polymers with narrow molecular weight distribution (Mw/Mn < 1.15) at high monomer conversion (∼90%). Interestingly, the results revealed that when tris(2-pyridylmethyl)-amine (TPMA) was used as a ligand, the amount of copper required to achieve similar control of the polymerization could be decreased 5 times. This system was successfully extended to the polymerization of oligo(ethylene oxide) methyl ether methacrylate (OEOMA). The high conversion and preservation of the chain-end functionality allows the direct synthesis of POEOMA-b-PDPA block copolymers. The low catalyst concentrations and benign nature of Na2S2O4 make this SARA ATRP method attractive for the synthesis of well controlled water soluble polymers for biomedical applications.

2-(Diisopropylamino)ethyl methacrylate (DPA) was polymerized by Atom Transfer Radical Polymerization (ATRP) using sodium dithionite (Na2S2O4) as a reducing agent and supplemental activator with a Cu(II)Br2/Me6TREN catalytic system at 40 °C in an isopropanol–water mixture. The effects of the solvent mixture and the initiator structure on the polymerization kinetics were studied. The eco-friendly catalytic system described is suitable for the synthesis of poly(2-(diisopropylamino)ethyl methacrylate) (PDPA) with controlled molecular weight, low dispersity, and well-defined chain-end functionality. Both linear and 4-arm star polymers with various target molecular weights were synthesised. The 1H NMR and MALDI-TOF analyses confirmed the molecular structure and high chain-end functionality of the obtained polymers. The use of an alkyne functionalized initiator allowed further azide–alkyne Huisgen cycloaddition with 3-azido-7-diethylamino-coumarin, a fluorescent biocompatible molecule.

1,1- Bis (trifluoromethyl)alkyl isocyanates obtained from perfluoroisobutene (PFIB) react with aroyl(arylsulfonyl)hydrazines. Twenty eight prospective biologically active polyfluorinated 1,4-substituted semicarbazides were synthesized. The structure of each new product was confirmed by analytical and spectroscopic methods. The Lipinski's and Gelovani's parameters were then calculated. Two adjustments to the Lipinski rules of five are suggested for fluorinated drug candidates.

Choline kinase alpha (ChoKα) overexpression is associated with an aggressive tumor phenotype. ChoKα inhibitors induce apoptosis in tumors, however validation of their specificity is difficult in vivo. We report the use of optical imaging to assess ChoKα status in cells and in vivo using JAS239, a carbocyanine-based ChoKα inhibitor with inherent near infrared fluorescence. JAS239 attenuated choline phosphorylation and viability in a panel of human breast cancer cell lines. Antibody blockade prevented cellular retention of JAS239 indicating direct interaction with ChoKα independent of the choline transporters and catabolic choline pathways. In mice bearing orthotopic MCF7 breast xenografts, optical imaging with JAS239 distinguished tumors overexpressing ChoKα from their empty vector counterparts and delineated tumor margins. Pharmacological inhibition of ChoK by the established inhibitor MN58b led to a growth inhibition in 4175-Luc+ tumors that was accompanied by concomitant reduction in JAS239 uptake and decreased total choline metabolite levels as measured using magnetic resonance spectroscopy. At higher therapeutic doses, JAS239 was as effective as MN58b at arresting tumor growth and inducing apoptosis in MDA-MB-231 tumors, significantly reducing tumor choline below baseline levels without observable systemic toxicity. These data introduce a new method to monitor therapeutically effective inhibitors of choline metabolism in breast cancer using a small molecule companion diagnostic.

The synthesis of polystyrene (PS) by atom transfer radical polymerization using the Fe(0)/CuBr2 catalytic system in dimethylformamide is reported. The effects of temperature, ligand, initiator structure, and monomer to solvent ratio on the polymerization kinetics are evaluated. PS with high molecular weight, low polydispersity, and telechelic structure are achieved and successfully used for further reinitiation or the copper(I)-catalyzed Huisgen 1,3-dipolar cycloaddition click reaction between alkyne- and azide-terminated PS. For the first time, suitable styrene polymerization rates are achieved using this cost-effective and environmentally attractive catalytic system. This method can be very useful in macromolecular engineering to afford PS-based materials with well-controlled structure.

Inorganic sulfites such as sodium dithionite (Na2S2O4), sodium metabisulfite (Na2S2O5), and sodium bisulfite (NaHSO3) have been studied as reducing agents for atom transfer radical polymerization (ATRP). They act not only as very efficient reducing agents but also as supplemental activators for SARA (supplemental activator and reducing agent) ATRP of methyl acrylate in DMSO at ambient temperature. In combination with Cu(II)Br2/Me6TREN, they produced poly(methyl acrylate) with controlled molecular weight, low dispersity (Mw/Mn = 1.05), and well-defined chain-end functionality. Sulfites are eco-friendly, approved by FDA as food and beverage additives, and used commercially in many industrial processes.

The current trend in developing next-generation LRP systems and in particular ATRP involves reduction, elimination, and/or replacement of toxic and highly expensive catalysts and solvents with environmently friendly ones. Here, the unexpected, accelerated, ambient-temperature ATRP of methyl acrylate catalyzed by a Fe(0)/CuBr2/Me6TREN system in a mixture of water and inexpensive and environmentally more friendly alcohols (methanol, ethanol, and 1-propanol) is reported. The data presented open up the possibility of using fast ATRP catalyzed by a mixed transition-metal catalyst system in solvents that are inexpensive, eco-friendly, and have low boiling points.

Controlled/“living” radical polymerization (CLRP) of vinyl chloride (VC) via the reversible addition–fragmentation chain transfer (RAFT) process is reported for the first time. The cyanomethyl methyl(phenyl)carbamodithioate (CMPCD) was found to be an efficient RAFT agent enabling the CLRP polymerization of VC monomer under certain experimental conditions. Two different radical initiators, having very distinct half-life times at room temperature, were employed in this study. The kinetic studies of RAFT polymerization of VC show a linear increase of the molecular weight with the monomer conversion and the lowest polydispersity (PDI) ever reported for poly(vinyl chloride) (PVC) synthesized with CLRP method (PDI ∼ 1.4). The resulting PVC was fully characterized using the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), 1H nuclear magnetic resonance spectroscopy (1H NMR), and gel permeation chromatography (GPC) techniques. The 1H NMR and MALDI-TOF-MS analysis of PVC ...

This work reports the preparation and study of poly(vinyl chloride) (PVC) with medium and high molecular weight using a Living Radical Polymerization (LRP) method in aqueous systems. The synthesis of ultra thermal stable PVC that falls outside the typical values known for the PVC industry is presented and PVC thermal stability is evaluated using a standard industrial method. The results presented in this manuscript suggest that the single electron transfer–degenerative transfer mediated living radical polymerization (SET–DTLRP) mechanism is the main factor influencing the thermal stability, since the polymerization temperature has no detectable effect on this property. In contrast to the Free Radical Polymerization (FRP), where low temperatures lead to PVC with high thermal stability that corresponds to a high molecular weight polymer, the polymerization temperature in SET–DTLRP (range 21–42 °C) has no detectable effect on the thermal stability of PVC. The final molecular weight is defined by the [monomer] 0 /[initiator] 0 ratio (degree of polymerization). The PVC synthesis reported in this manuscript was carried out in a 150 L pilot reactor, which represents a reliable approach in terms of hydrodynamic conditions, when compared with those at the industrial scale.

In this article, the characterization of the first near-infrared (NIR) phospholipase-activated molecular beacon is reported, and its utility for in vivo cancer imaging is demonstrated. The probe consists of three elements: a phospholipid (PL) backbone to which the NIR fluorophore, pyropheophorbide a (Pyro), and the NIR Black Hole Quencher 3 (BHQ) were conjugated. Because of the close proximity of BHQ to Pyro, the Pyro-PtdEtn-BHQ probe is self-quenched until enzyme hydrolysis releases the fluorophore. The Pyro-PtdEtn-BHQ probe is highly specific to one isoform of phospholipase C, phosphatidylcholine-specific phospholipase C (PC-PLC), responsible for catabolizing phosphatidylcholine directly to phosphocholine. Incubation of Pyro-PtdEtn-BHQ in vitro with PC-PLC demonstrated a 150-fold increase in fluorescence that could be inhibited by the specific PC-PLC inhibitor tricyclodecan-9-yl xanthogenate (D609) with an IC(50) of 34 ± 8 μM. Since elevations in phosphocholine have been consistently observed by magnetic resonance spectroscopy in a wide array of cancer cells and solid tumors, we assessed the utility of Pyro-PtdEtn-BHQ as a probe for targeted tumor imaging. Injection of Pyro-PtdEtn-BHQ into mice bearing DU145 human prostate tumor xenografts followed by in vivo NIR imaging resulted in a 4-fold increase in tumor radiance over background and a 2 fold increase in the tumor/muscle ratio. Tumor fluorescence enhancement was inhibited with the administration of D609. The ability to image PC-PLC activity in vivo provides a unique and sensitive method of monitoring one of the critical phospholipase signaling pathways activated in cancer, as well as the phospholipase activities that are altered in response to cancer treatment.

The aim of this work is to evaluate PVC resins prepared by Single Electron Transfer Degenerative Chain Transfer Living Radical Polymerisation (SET-DTLRP) in a 150 L reactor under industrial conditions. The product features were analysed considering the standard resin features of PVC prepared by the conventional free radical polymerisation (FRP) method. It was proved that the FRP and SET-DTLRP have different particle growing mechanism and led to grains with completely different features (particle size, particle size distribution and morphology). It is critical for the PVC producers the preparation of PVC with a predetermined grain shape, particle size distribution and porosity which have an indubitable influence on polymer processing. It is presented a detailed study on the particle formation of the PVC synthesised by SET-DTLRP providing first insights into PVC features associated with a new polymerisation technique taking into account the normal requirements of the PVC industry. A possible mechanism of the SET-DTLRP particle formation is proposed.

α,ω-di(iodo) poly(isobornyl acrylate) macroiniators (α,ω-di(iodo)PIA) with number average molecular weight from Mn,TriSEC = 11,456 to Mn,TriSEC = 94,361 were synthesized by single electron transfer-degenerative chain transfer mediated living radical polymerization (SET-DTLRP) of isobornyl acrylate (IA) initiated with iodoform (CHI3) and catalyzed by sodium dithionite (Na2S2O4) in water at 35 °C. The plots of number average molecular weight vs conversion and ln{[M]0/[M]} vs time are linear, indicating a controlled polymerization. α,ω-di(iodo) poly(isobornyl acrylate) have been used as a macroinitiator for the SET-DTLRP of vinyl chloride (VCM) leading to high Tg block copolymers PVC-b-PIA-b-PVC. The dynamic mechanical thermal analysis of the block copolymers suggests just one phase indicating that copolymer behaves as a single material. This technology provides the possibility of synthesizing materials based on PVC with higher Tg in aqueous medium. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009

Living radical polymerization of 2-methoxyethyl acrylate (MEA) was achieved by single-electron-transfer/degenerative transfer mediated living radical polymerization (SET-DTLRP) in water catalyzed by sodium dithionate. The poly(2-methoxyethyl acrylate) is an amphiphilic polymer with a hydrophobic part (polyethylene chain) and a mildly hydrophilic tail. The plots of number-average molecular weight versus conversion and ln{[M]0/[M]} versus time are linear, indicating a controlled polymerization. This method leads to the preparation of α,ω-di(iodo) poly(2-methoxyethyl acrylate)s (α,ω-di(iodo)PMEA) macroinitiators that can be further functionalized. The molecular weight distributions were determined using a combination of three detectors (TriSEC): right-angle light scattering (RALLS), a differential viscometer (DV) and refractive index (RI). The method studied in this work represents a possible route to prepare well-tailored macromolecules made of 2-methoxyethyl acrylate (biocompatible material) in an environmentally friendly reaction medium. To the best of our knowledge there is no previous report dealing with the synthesis of PMEA by any LRP approach in aqueous medium. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4454–4463, 2009

The aim of this work is to the study the influence of the isomer structures of butyl acrylate monomer on the single-electron transfer/degenerative chain transfer mediated living radical polymerization (SET-DTLRP). The kinetic of isobutyl acrylate is determined for the first time by SET-DTLRP in water catalyzed by sodium dithionite. The plots of number-average molecular weight versus conversion and ln([M]0/[M]) versus time are linear, demonstrating a controlled polymerization. The influence of the isomer t-butyl, i-butyl, and n-butyl on the kinetics, properties, and stereochemistry of the reactions was assessed. To the best of our knowledge, there is no previous report dealing with the synthesis of PiBA by any LRP approach in aqueous medium. The results presented in this work suggest that the stability provided by the acrylate side group has an important influence in the polymerization process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6542-6551, 2008

Living radical polymerization of ethyl acrylate was achieved by single-electron-transfer/degenerative-chain transfer mediated living radical polymerization in water catalyzed by sodium dithionite. The plots of number-average molecular weight versus conversion and In[M]/[M] versus time are linear, indicating a controlled polymerization. This method leads to the preparation of α,α-di(iodo)poly(ethyl acrylate) (α,ω-di(iodo)PEtA) macroinitiator that can be further functionalized. The molecular weight distributions were determined using a combination of three detectors (TriSEC): right-angle light scattering, a differential viscometer and refractive index. The method studied in this work represents a possible route to prepare well-tailored macromolecules made of ethyl acrylate in environmental friendly reaction medium. To the best of our knowledge there is no previous report dealing with the synthesis of PEtA by any LRP approach in aqueous medium. Furthermore, the method described in this article was successfully applied in pilot scale reactions under industrial production conditions.

BACKGROUND: The search for new potent inhaled anesthetics has slowed, in large part because of the excellence of the two most recent additions, desflurane and sevoflurane. Nonetheless, neither desflurane nor sevoflurane are ideal anesthetics, desflurane causing cardiorespiratory stimulation, and sevoflurane having a slower (albeit rapid) recovery from anesthesia. Sevoflurane also can produce convulsions and postoperative agitation. METHODS AND RESULTS: In the present report, we describe the physical and anesthetic properties of 31 cyclic ethers halogenated solely with fluorine. Although several produced anesthesia, none had solubilities that would make them better than sevoflurane. The remaining ethers were unstable or produced obvious central nervous system irritation, including convulsions. CONCLUSIONS: We find that none of these cyclic ethers appear to provide advantages over desflurane or sevoflurane.

It is well established that lipid metabolism is drastically altered during tumor development and response to therapy. Choline kinase alpha (ChoKα) is a key mediator of these changes, as it represents the first committed step in the Kennedy pathway of phosphatidylcholine biosynthesis and ChoKα expression is upregulated in many human cancers. ChoKα activity is associated with drug resistant, metastatic, and malignant phenotypes, and represents a robust biomarker and therapeutic target in cancer. Effective ChoKα inhibitors have been developed and have recently entered clinical trials. ChoKα's clinical relevance was, until recently, attributed solely to its production of second messenger intermediates of phospholipid synthesis. The recent discovery of a non-catalytic scaffolding function of ChoKα may link growth receptor signaling to lipid biogenesis and requires a reinterpretation of the design and validation of ChoKα inhibitors. Advances in positron emission tomography, magnetic resonance spectroscopy, and optical imaging methods now allow for a comprehensive understanding of ChoKα expression and activity in vivo. We will review the current understanding of ChoKα metabolism, its role in tumor biology and the development and validation of targeted therapies and companion diagnostics for this important regulatory enzyme. This comes at a critical time as ChoKα-targeting programs receive more clinical interest.

We present the synthesis and characterization of F18-labeled fluorinated derivatives of resazurin, a probe for cell viability. The compounds were prepared by direct fluorination of resazurin with diluted [F18]-F2 gas under acidic conditions. The fluorination occurs into the ortho-positions to the hydroxyl group producing various mono-, di-, and trifluorinated derivatives. The properties of the fluorinated resazurins are similar to the parent compound with the addition of fluorine leading to decreased pKa values and a bathochromic shift of the absorption maxima. The fluorinated resazurin derivatives can be used as probes for observation of cell viability in various cells, tissues and organs using a combination of positron emission tomography and direct optical imaging of Cerenkov luminescence.

A new method is described for producing 3,3,3-trifluoroethyl isocyanate from perfluoroisobutene (PFIB). Isocyanate was used for synthesis of carbamates and ureas. A series of trifluoroethyl-substituted ureas has been tested in the National Cancer Institute (NCI, Bethesda, USA) by the NCI-60 DTP Human Tumor Cell Line Screening Program at a single high dose (10−5 M). The moderate anticancer activity was shown against some types of cancer on the individual human cell lines for leukemia, non-small cell lung cancer and renal cancer.

Dual-energy (DE) mammography has recently entered the clinic. Previous theoretical and phantom studies demonstrated that silver provides greater contrast than iodine for this technique. Our objective was to characterize and evaluate in vivo a prototype silver contrast agent ultimately intended for DE mammography. The prototype silver contrast agent was synthesized using a three-step process: synthesis of a silver core, silica encapsulation and PEG coating. The nanoparticles were then injected into mice to determine their accumulation in various organs, blood half-life and dual-energy contrast. All animal procedures were approved by the institutional animal care and use committee. The final diameter of the nanoparticles was measured to be 102 (±9) nm. The particles were removed from the vascular circulation with a half-life of 15 min, and accumulated in macrophage-rich organs such as the liver, spleen and lymph nodes. Dual-energy subtraction techniques increased the signal difference-to-noise ratio of the particles by as much as a factor of 15.2 compared to the single-energy images. These nanoparticles produced no adverse effects in mice. Silver nanoparticles are an effective contrast agent for dual-energy x-ray imaging. With further design improvements, silver nanoparticles may prove valuable in breast cancer screening and diagnosis. • Silver has potential as a contrast agent for DE mammography. • Silica-coated silver nanoparticles are biocompatible and suited for in vivo use. • Silver nanoparticles produce strong contrast in vivo using DE mammography imaging systems.

This work reports the synthesis of several copolymers of poly(vinyl chloride)-b-poly(n-butyl acrylate)-b-Poly(vinyl chloride) prepared by single electron transfer/degenerative chain transfer mediated living radical polymerization (SET-DTLRP) in a two step process: first, a bifunctional macroinitiator of α,ω-di(iodo)poly(butyl acrylate) [α,ω-di(iodo)PBA] was synthesized by SET-DTLRP in water at 30 °C. The obtained macroinitiator was further reinitiated also by SET-DTLRP leading to the formation of the desired product. Several copolymers were synthesized in a 5L pilot reactor with different molecular weights and relative amounts of PBA and PVC. The possibility of synthesizing flexible materials made of PVC without using normal free plasticizes is extremely important for the industry. After processing the materials in a two-roll mill laboratorial equipment, the block copolymers were characterized concerning thermal and mechanical. The materials characterized in this study were prepared in a 5L pilot reactor under similar conditions to be used in industrial scale.

To accelerate the living radical polymerization (LRP) of vinyl chloride (VC) in water the phase transfer catalyzed single electron transfer- degenerative chain transfer mediated living radical polymerization (SET-DTLRP) of VC mediated by sodium dithionite (Na2S2O4) was investigated. The fastest polymerization reaction that still produces ther- mally stable poly(vinyl chloride) (PVC) takes place at 43 °C with the ratio (PTC)0/ (Na2S2O4)0 0.0075/1. Cetyltrimethylammonium bromide (nC16H33(CH3)3N Br, CetMe3NBr) was the phase-transfer catalyst (PTC) of choice. Under these conditions the first, fast stage of SET-DTLRP of VC was accomplished within 7- 8 h when the initial ratio monomer/initiator (VC)0/(CHI3)0 was 800. The number-average molecular weight (Mn )o f the resulting PVC was in good agreement with the theoretical molecular weight (Mth). When the (VC)0/(CHI3)0 ratio was 4800, the fast step of the reaction was accomplished within 17 h, to produce 72% monomer conversion. A deviation of the Mn from the Mth was observed in this case. Possible mechanistic explanations for this deviation as well as for the phase transfer catalyzed SET-DTLRP of VC were suggested. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 779 -788, 2005

A variety of conditions, including catalysts [CuCl, CuI, Cu2O, and Cu(0)], ligands [2,2′-bipyridine (bpy), tris(2-dimethylaminoethyl)amine (Me6-TREN), polyethyleneimine, and hexamethyl triethylenetetramine], initiators [CH3CHClI, CH2I2, CHI3, and F(CF2)8I], solvents [diphenyl ether, toluene, tetrahydrofuran, dimethyl sulfoxide (DMSO), dimethylformamide, ethylene carbonate, dimethylacetamide, and cyclohexanone], and temperatures [90, 25, and 0 °C] were studied to assess previous methods for poly(methyl methacrylate)-b-poly(vinyl chloride)-b-poly(methyl methacrylate) (PMMA-b-PVC-b-PMMA) synthesis by the living radical block copolymerization of methyl methacrylate (MMA) initiated with α,ω-di(iodo)poly(vinyl chloride). CH3CHClI was used as a model for α,ω-di(iodo)poly(vinyl chloride) employed as a macroinitiator in the living radical block copolymerization of MMA. Two groups of methods evolved. The first involved CuCl/bpy or Me6-TREN at 90 °C, whereas the second involved Cu(0)/Me6-TREN in DMSO at 25 or 0 °C. Related ligands were used in both methods. The highest initiator efficiency and rate of polymerization were obtained with Cu(0)/Me6-TREN in DMSO at 25 °C. This demonstrated that the ultrafast block copolymerization reported previously is the most efficient with respect to the rate of polymerization and precision of the PMMA-b-PVC-b-PMMA architecture. Moreover, Cu(0)/Me6-TREN-catalyzed polymerization exhibits an external first order of reaction in DMSO, and so this solvent has a catalytic effect in this living radical polymerization (LRP). This polymerization can be performed between 90 and 0 °C and provides access to controlled poly(methyl methacrylate) tacticity by LRP and block copolymerization. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1935–1947, 2005

α,ω-Di(iodo)poly(vinyl chloride)s [α,ω-di(iodo)PVCs] with number-average molecular weights ranging from 2100 to 20,000 and weight-average molecular weight/number-average molecular weight ratios ranging from 1.72 to 2.16 were synthesized through the single-electron-transfer/degenerative-chain-transfer mediated living radical polymerization of vinyl chloride initiated with iodoform and catalyzed by sodium dithionite in water at 25–35 °C. These α,ω-di(iodo)PVCs were used as macroinitiators for the metal-catalyzed living radical block copolymerization of methyl methacrylate to produce poly(methyl methacrylate)-b-poly(vinyl chloride)-b-poly(methyl methacrylate) block copolymers. By searching various copper derivatives, ligands, and solvents, it has been found that CuCl/tris(2-dimethylaminoethyl)amine in dimethyl sulfoxide at 90 °C provides an accelerated method for the synthesis of block copolymers. Poly(methyl methacrylate)-b-poly(vinyl chloride)-b-poly(methyl methacrylate) block copolymers with number-average molecular weights of 41,000–106,700 were produced by this method in 30–80 min. These reaction times were within the range of induction times exhibited when the same block copolymers were synthesized with CuCl/2,2′-bipyridine in diphenyl ether at 90 °C. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1649–1659, 2005

α,ω-Di(iodo)poly(2-ethylhexyl acrylate)s [α,ω-di(iodo)P2EHAs] with number-average molecular weights of 13,700 and 20,400 were synthesized by the single-electron-transfer/degenerative-chain-transfer mediated living radical polymerization (SET–DTLRP) of 2-ethylhexyl acrylate initiated with iodoform and catalyzed by sodium dithionite in water at 23 and 30 °C. These α,ω-di(iodo)P2EHAs were used as macroinitiators for the SET–DTLRP of vinyl chloride, which was carried out under similar reaction conditions to synthesize ABA block copolymers containing poly(vinyl chloride) in the A blocks and poly(2-ethylhexyl acrylate) in the B block. Poly(vinyl chloride)-b-poly(2-ethylhexyl acrylate)-b-poly(vinyl chloride) was synthesized with 100% initiator efficiency. This synthetic method provides for the first time access to a diversity of block copolymers and other complex architectures based on combinations of thermoplastic poly(vinyl chloride)and elastomeric polyacrylates. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2276–2280, 2005