1,3-Bis(2-chloroethyl)-1-nitrosourea enhances the inhibitory effect of Resveratrol on 5-fluorouracil sensitive/resistant colon cancer cells

AIM:To study the mechanism of 5-fluorouracil(5-FU)resistance in colon cancer cells and to develop strategies for overcoming such resistance by combination treatment.METHODS:We established and characterized a 5-FU resistance(5-FU-R)cell line derived from continuous exposure(25μmol/L)to 5-FU for 20 wk in 5-FU sensitive HCT-116 cells.The proliferation and expression of different representative apoptosis and anti-apoptosis markers in 5-FU sensitive and 5-FU resistance cells were measured by the MTT assay and by Western blotting,respectively,after treatment with Resveratrol(Res)and/or 1,3-Bis(2-chloroethyl)-1-nitrosourea(BCNU).Apoptosis and cell cycle arrest was measured by 4',6'-diamidino-2-phenylindole hydrochloride staining and fluorescence-activated cell sorting analysis,respectively.The extent of DNA damage was measured by the Comet assay.We measured the visible changes in the DNA damage/repair cascade by Western blotting.RESULTS:The widely used chemotherapeutic agents BCNU and Res decreased the growth of 5-FU sensitive HCT-116 cells in a dose dependent manner.Combined application of BCNU and Res caused more apoptosis in5-FU sensitive cells in comparison to individual treatment.In addition,the combined application of BCNU and Res caused a significant decrease of major DNA base excision repair components in 5-FU sensitive cells.We established a 5-FU resistance cell line(5-FU-R)from 5-FU-sensitive HCT-116(mismatch repair deficient)cells that was not resistant to other chemotherapeutic agents(e.g.,BCNU,Res)except 5-FU.The 5-FU resistance of 5-FU-R cells was assessed by exposure to increasing concentrations of 5-FU followed by the MTT assay.There was no significant cell death noted in5-FU-R cells in comparison to 5-FU sensitive cells after5-FU treatment.This resistant cell line overexpressed anti-apoptotic[e.g.,AKT,nuclear factorκB,FLICE-like inhibitory protein),DNA repair(e.g.,DNA polymerase beta(POL-β),DNA polymerase eta(POLH),protein Flap endonuclease 1(FEN1),DNA damage-binding protein 2(DDB2)]and 5-FU-resistance proteins(thymidylate synthase)but under expressed pro-apoptotic proteins(e.g.,DAB2,CK1)in comparison to the parental cells.Increased genotoxicity and apoptosis were observed in resistant cells after combined application of BCNU and Res in comparison to untreated or parental cells.BCNU increased the sensitivity to Res of 5-FU resistant cells compared with parental cells.Fifty percent cell death were noted in parental cells when 18μmol/L of Res was associated with fixed concentration(20μmol/L)of BCNU,but a much lower concentration of Res(8μmol/L)was needed to achieve the same effect in 5-FU resistant cells.Interestingly,increased levels of adenomatous polyposis coli and decreased levels POL-β,POLH,FEN1 and DDB2 were noted after the same combined treatment in resistant cells.CONCLUSION:BCNU combined with Res exerts a synergistic effect that may prove useful for the treatment of colon cancer and to overcome drug resistance.

Synthesis and Crystal Structure of 3,3'-Bis(5-(N-(4-hydroxylphenyl)imidomethyl)- pyrrol-2-yl)pentane·2CH_3OH

3,3＇-Bis（5-（N-（4-hydroxylphenyl）imidomethyl）pyrrol-2-yl）pentane 1 has been synthesized and characterized. The crystal of its methanol complex, 1·（CH3OH）2, belongs to the orthorhombic system, space group Pccn with a = 18.094（2）, b = 11.6890（16）, c = 13.3629（19） , V = 2826.3（7） 3, Z = 8, C14.5H18N2O2, Mr = 252.31, Dc = 1.186 g/cm3, F（000） = 1080 and μ（MoKα） = 0.080 mm-1. The final R = 0.0662 and wR = 0.1801 for 1908 observed reflections with I 2σ（I）, and R = 0.0800 and wR = 0.1948 for all reflections. In the solid state, bridged by included methanol molecules, the molecules of compound 1 form interpenetrated grid structure through N–H···O and O–H···O hydrogen bonds.

Catalytic Kinetic on the Thermal Decomposition of Ammonium Perchlorate with a New Energetic Complex Based on 3,5-Bis(3-pyridyl)-1H-1,2,4-triazole

A new energetic complex,[Co（3,3？-Hbpt）（Htm）]·H_2O（1,3,3？-Hbpt = 3,5-bis（3-pyridyl）-1H-1,2,4-triazole and H_3tm = trimesic acid）,has been synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction,elementary analysis,IR spectroscopy,thermogravimetric analysis and X-ray powder diffraction. Single-crystal X-ray diffraction indicates that the complex belongs to triclinic system,space group P 1 with a = 10.0911（1）,b = 10.2573（1）,c = 10.6393（1） ？,α = 103.793（2）,β = 101.041（2）,γ = 107.918（3）o,V = 974.9（2） ？~3,Z = 2,D_c = 1.732 g·cm-3,μ = 0.941 mm^（-1）,M_r = 508.31,F（000） = 518,the final R = 0.0523 and wR = 0.0935 with I 〉 2σ（I）. In the title complex,Co（Ⅱ） ions are connected by Htm2-anions generating 1D ladder-like chains which are linked by 3,3？-Hbpt to form 1D cages. In addition,the thermal decomposition of ammonium perchlorate（AP） with complex 1 was explored by differential scanning calorimetry（DSC）. AP is completely decomposed in a shorter time in the presence of complex 1,and the decomposition heat of the mixture is 2.531 kJ·g^（-1）,significantly higher than that of pure AP. By Kissinger＇s method,the ratio of Ea/ln（A） is 11.05 for the mixture,which indicates that complex 1 shows good catalytic activity toward the AP decomposition.

Synthesis and Crystal Structure of 2,6-Bis(2-pyridinylmethyl)-3,5-bis(2-hydroxyl-5-chlorophenyl)pyrazine

The title compound,2,6-bis（2-pyridinylmethyl）-3,5-bis（2-hydroxyl-5-chlorophe nyl）-pyrazine（C26H12Cl2N4O2C2H8O2,Mr=551.41）,has been synthesized and characterized by LC-ESIMS,NMR,UV and IR spectroscopy as well as by X-ray single-crystal diffraction.The compound behaves as a substituted pyrazine.The hydrogen atoms on C（2） and C（3） are substituted by 2-pyridinyl,whereas those on C（1） and C（4） are substituted by 2-hydroxyl-5-chlorophenyl.It crystallizes in the monoclinic system,space group P21/c with a=8.9433（12）,b=32.003（4）,c=10.5209（18）,β=111.199（2）°,V=2807.5（7）3,Z=4,Dc=1.305 mg/m3,F（000）=1144 and μ=0.094 mm-1.A total of 13235 reflections were collected in the range of 2.17～25.01o by using a phi and omega scan mode,of which 4923 were unique（Rint=0.0692） and 2872 observed reflections with Ⅰ 〉2σ（Ⅰ） were used in the structure solution and refinement.

Synthesis,Crystal Structure,and Magnetic Property of One 3D Nickel Coordination Polymer Based on 2-Hydroxy-5-(3',5'-terephthalic acid)Pyridine and 1,4-Bis(1-imdazoly)benzene

One novel nickel coordination polymer, {[Ni（OTP）（bib）1.5（H2O）]·2H2O}n（1, H2 OTP = 2-hydroxy-5-（3＇,5＇-terephthalic acid） pyridine, bib = 1,4-bis（1-imdazoly）benzene）, has been synthesized and characterized by elemental analysis（EA）, IR, powder X-ray diffraction（PXRD）, and thermogravimetric（TG） analyses. The crystal of 1 crystallizes in monoclinic, space group P21/n with a = 12.2860（5）, b = 13.8246（6）, c = 19.0140（8） A, β = 104.3870（1）°, V = 3128.2（2） A3, Z = 4, C32H28N7 Ni O8, Mr = 697.32, Dc = 1.481 g/cm^3, F（000） = 1444 and μ（Mo Kα） = 0.684 mm-1. The final R = 0.0704 and w R = 0.1764 for 5485 observed reflections with I 2σ（I） and R = 0.1087 and wR = 0.2010 for all data. Topology analysis reveals that complex 1 is a 3D 2-fold interpenetrated {4^4·6^6}-nov net based on the 1D [Ni（OTP）]n chain and the 2D [Ni2（bib）3]n sql sheet. And the variable-temperature magnetic susceptibility measurements exhibit weak antiferromagnetic coupling interaction.

Synthesis and Crystal Structure of 2,5-Bis(morpholino)-3,4-bis(p-chlorophenyl)thiophene

The title compound 2,5-bis(morpholino)-3,4-bis(p-chlorophenyl) thiophene 2 was obtained by the reaction of -thio-p-chlorobenzoyl thioformmorpholine 1 with trimethyl phosphite in refluxing xylene. The crystal is of triclinic, space group P?with unit cell constants: a = 6.0740(1), b = 10.3250(1), c = 19.779(2) , ?= 76.740(1), = 87.110(1), = 74.920(1), C24H24Cl2N2O2S, Mr = 475.41, Z = 2, V = 1165.7(3) ?, Dc = 1.354 g/cm3, (MoK) = 0.71073, = 0.392 mm-1, F(000) = 496, the final R = 0.0324 and wR = 0.0819 for 3102 observed reflections (I > 2(I)). X-ray analysis reveals that the two morpholinyl groups are located at the -position of thiophene, and the two p-chlorophenyl groups at the -position. Therefore, the title compound is a new symmetric thiophene derivative.

Crystal and Molecular Structure, and Spectral Characteristics of Sodium 3,5-Bis(Hydroxyimino)-1-Methyl-2,4,6-Trioxocyclohexanide

Sodium 3,5-bis(hydroxyimino)-1-methyl-2,4,6-trioxocyclohexanide C7H5N2NaO5 (I) has been isolated as the only product of the reaction of nitrosation of methylphloroglucinol. The structure of the titled compound has been determined from single crystal X-ray diffraction data. The hydrated C7H5N2NaO52.5H2O crystallizes in the monoclinic space group C2/c, with a(?) 16.408(3);b(?) 12.446(3);c(?) 13.716(3);(o) 126.34(3). The planar organic anion exists in a triketo-dihydroxyimino form with the C–O and C–N distances from 1.220(2) to 1.271(2)?? and from 1.292(2) to 1.293?? respectively. In the IR spectrum of I, the sharp absorption band occurred at 1681 cm-1 due to C=O stretching indicating the strong H-interactions. The correlations of theoretical (DFT-B3LYP/aug-cc-pVDZ) and experimental UV-vis absorption spectra in neutral and alkaline ethanolic solutions showed the existence of hydroxyimino-nitroso tautomerism while ionization of I.

Determination of Trace Manganese (Ⅱ) by Its Catalytic De-colourizing Reaction On the Aerial Oxidation of 1.5-his (2-hydroxy-5-chlorophenyl)-3-cyanoformazan and Its Kinetic Reaction Mechanism

A kinetie method is described for the determination of trace amounts of mangancsc (Ⅱ)based on its catalylic effect on the aerial oxidation of 1.5-bis (2-hydroxy-5-chlorophenyl)-3-cyanofrmazan. The reaction is followed spectrophotometrically by measurin the rate of change in absorbance at 580nm. The calibration curve (rate constant vs. manganese concentration) is linearin the range of 10~200ng in 25ml solutions. Kinetic parameters of the reaction are reported. Thereare few Interferences.

A Zn(Ⅱ) Coordination Polymer Based on a Flexible Polycarboxylate Ligand 5-(4-Hydroxypyridinium-1-ylmethyl)-isophthalic Acid: Synthesis, Structure, and Property

A Zn（Ⅱ） supramolecular coordination polymer, {[Zn2（L）2（m-bix）（H20）]6H2O}n（1）, with an interesting 1D→2D polythreading array from a flexible and angular organic aromaticpolycarboxylate ligand 5-（4-hydroxypyridinium-l-ylmethyl）isophthalic acid （H2L）, and N-donorligand 1,3-bis（imidazol-l-ylmethyl）benzene （m-bix）, has been obtained under hydrothermalconditions and characterized by elemental analysis, powder X-ray diffraction （PXRD）, IR, thermalgravimetric analyses （TGA） and single-crystal X-ray diffraction. In 1, the Zn（Ⅱ） center has twocoordination geometries. One exhibits a trigonal bipyramidal coordination sphere, and the other isa tetrahedral geometry; L2- has two different coordination modes, with one connecting three Zn（Ⅱ）ions through two monodentate carboxylate groups and the monodentate hydroxyl group, and theother bridging two Zn（Ⅱ） ions through two carboxylate groups. The L2- anions connect the Zn（Ⅱ）centers forming an infinite 1D tubular structure. These 1D tubes are interconnected by the m-bixspacers to form a 2D framework. Such 2D layers are further assembled into a 3D supramolecularnetwork via hydrogen bonds. Meanwhile, the luminescent property of 1 has also been investigatedin detail.

A New Co(Ⅱ)Coordination Compound Constructed by Tripyridyltriazole and Pyromellitic Acid:Synthesis,Crystal Structure and Antifungal Activity

A new coordination compound, [Co（L223）2（H2O）2]·H2pm（1, L223 = 3,4-bis（2-pyridyl）-5-（3-pyridyl）-1,2,4-triazole and H4 pm = pyromellitic acid）, has been synthesized. The structure of complex 1 has been characterized by X-ray single-crystal diffraction, elemental analysis, IR spectrum analysis and thermogravimetric analysis. Single-crystal X-ray diffraction analysis reveals that complex 1 belongs to the triclinic system, space group P1 with a = 10.2470（8）, b = 10.2879（9）, c = 10.2951（11） ？, α = 109.398（2）, β = 97.6590（10）, γ = 95.3260（10）°, V = 1003.60（16） ？3, Z = 1, Dc = 1.565 g/cm^3, μ = 0.508 mm%^-1, Mr = 945.73, F（000） = 485, the final R = 0.0562 and w R = 0.0783 with I 〉 2σ（I）. Two L223 as chelating ligands link one Co（II） ion to form a 0D motif. Furthermore, the 0D motifs are linked into a 2D coordination pattern with hydrogen bonds. In addition, the antifungal effects of the ligand and the complex were evaluated by the disc diffusion method against Colletotrichum gloeosporioides Penz. 1 represents antifungal activity with high levels of inhibitory potency which is larger than the corresponding ligand.

Improved stability of blue TADF organic electroluminescent diodes via OXD-7 based mixed host

Thermally activated delayed fluorescence(TADF)organic light-emitting diodes(OLEDs)have been demonstrated in applications such as displays and solid-state lightings.However,weak stability and ineffi-cient emission of blue TADF OLEDs are two key bottlenecks limiting the development of solution processable displays and white light sources.This work presents a solution-processed OLED using a blue-emitting TADF small molecule bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone(DMAC-DPS)as an emitter.We comparatively investigated the effects of single host poly(Nvinylcarbazole)(PVK)and a co-host of 60%PVK and 30%2,2′-(1,3-phenylene)-bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole](OXD-7)on the device performance(the last 10%is emitter DMAC-DPS).The co-host device shows lower turn-on voltage,similar maximum luminance,and much slower external quantum efficiency(EQE)rolloff.In other words,device stability improved by doping OXD-7 into PVK,and the device impedance simultaneously and significantly reduced from 8.6103 to 4.2103 W at 1000 Hz.Finally,the electroluminescent stability of the co-host device was significantly enhanced by adjusting the annealing temperature.

Synthesis, Structure and Photophysical Properties of Silole-Oxadiazole Copolymers

A new conjugated copolymer （PTST-DyOXD） derived from 1,1-dimethyl-3,4-diphenyl-2,5-bis（5-bromo-2- thienyl）-silole （TST） and 2,5-bis（4-ethynylphenyl）-l,3,4-oxadiazole （DyOXD） was synthesized by Pd（0）-catalyzed Sonogashira coupling reaction. For comparison, another copolymer without acetenyl group （PTST-OXD） was also synthesized by Pd（0）-catalyzed Suzuki coupling reaction. Chemical structures and optoelectronic properties of the copolymers were characterized by IH NMR, 13C NMR, IR, UV-vis absorption, photoluminescence and cyclic voltammetry. The number-average molecular weight （Mn） is 4010 Da for PTST-DyOXD and 3890 Da for PTST-OXD, respectively. The thermogravimetric analysis （TGA） measurements show that they have good thermal stability with decomposition temperature at 312 and 318 ~C, respectively. The optical band gap is 2.21 eV for PTST-DyOXD and 2.10 eV for PTST-OXD based on the absorption onset. CV analysis revealed the LUMO level of PTST-DyOXD is -3.04 eV, lower than that of PTST-OXD （about -2.89 eV）, which is attributed to the introduction of acetylene group in PTST-DyOXD, increasing the system of the conjugate chain length.