Dihydromyricetin Inhibits Tumor Growth and Epithelial-Mesenchymal Transition through regulating miR-455-3p in Cholangiocarcinoma.

Cholangiocarcinoma (CCA) leads to poor prognosis due to high aggressiveness and common chemoresistance. Dihydromyricetin (DMY), the main bioactive compound isolated from Ampelopsis grossedentata, exhibits broad anti-tumor effects. This study aimed to investigate the inhibitory effect of DMY on CCA tumor growth and epithelial-mesenchymal transition (EMT) and its underlying mechanism in CCA. DMY treatment significantly inhibited cell proliferation and EMT in CCA cell lines. The expression of ZEB1 and vimentin were down-regulated, while the level of E-cadherin was increased after DMY treatment. By analyzing the TCGA dataset, we found that miR-455 expression was significantly downregulated, while the level of ZEB1 was up-regulated in human CCA tumor tissues compared to normal samples. Mechanistic studies showed that ZEB1 was a direct target of miR-455-3p in CCA. Moreover, DMY treatment potently increased miR-455-3p expression and inhibited ZEB1 expression. Inhibition of miR-455-3p expression abolished DMY's inhibitory effects on tumor growth and EMT in both CCA cells and cell-engrafted nude mice. Finally, DMY significantly suppressed the expressions of p-PI3K and p-AKT, while silencing miR-455-3p remarkably abrogated the inhibitory effect. In conclusion, DMY suppresses tumor growth and EMT through regulating miR-455-3p in human cholangiocarcinoma, suggesting a potential option for CCA treatment.

Dihydromyricetin inhibits cell proliferation, migration, invasion and promotes apoptosis via regulating miR-21 in Human Cholangiocarcinoma Cells.

Dihydromyricetin, the most abundant natural flavonoid isolated from Ampelopsis grossedentata, exhibits broad anti-tumor effects. However, the effects of dihydromyricetin on cholangiocarcinoma remain unclear. This study examined the anti-tumor effects of dihydromyricetin in two human cholangiocarcinoma cell lines HCCC9810 and TFK-1, and the underlying mechanism was also investigated. Our study was the first to show that dihydromyricetin significantly inhibited cell proliferation, migration, invasion and promoted apoptosis in cholangiocarcinoma cells. By analyzing the TCGA dataset, we found that expression of miR-21, an oncogene and a potential target of anticancer drugs for cholangiocarcinoma, was upregulated in cholangiocarcinoma tissues compared to paired control tissues. Moreover, dihydromyricetin significantly reduced the expression of miR-21 in a dose-dependent manner. Overexpression of miR-21 remarkably abolished the inhibitory effects of dihydromyricetin on cell proliferation, migration, invasion and abrogated its effect of promoting cell apoptosis in both HCCC9810 and TFK-1 cells. Dihydromyricetin remarkably increased the expression of PTEN and decreased the expression of phosphorylated Akt, while overexpression of miR-21 abrogated the modulation of PTEN/ Akt pathway by dihydromyricetin. Taken together, our study demonstrates that dihydromyricetin inhibits cell proliferation, migration, invasion and promotes apoptosis in cholangiocarcinoma cells via regulating miR-21.

[Effect of a Comprehensive Improvement Project on Water Quality in Urban Lakes: A Case Study of Water Quality Variation in Lihu Lake Over the Past 30 Years].

In order to improve water quality, many urban lakes in China have undergone environmental restoration since the introduction of China's tenth five-year plan. To understand the effectiveness of improvement projects on eutrophic urban lakes, we analyze the changes in water quality of Lihu Lake over the past 30 years, i.e., before and after comprehensive remediation. We use long-term monitoring data from TLLER and from two regional investigations undertaken in 2017. The results were as follows. ① Concentrations of total nitrogen (TN) and total phosphorus (TP), the permanganate index, and chlorophyll-a (Chl-a) in Lihu Lake all increased dramatically since the 1990s and reached the worst levels during the period from 1997 to 2003. After comprehensive improvement measures for the lake undertaken by the local government in 2003, the water quality improved remarkably year by year, but reduced slightly in the past two years assessed here. There was no obvious improvement in water transparency when comparing data from before to after the remediation. ② Before the improvement measures, the water quality fluctuated greatly with season, however, water quality sampled during the winter post remediation was significantly better than during the summer. ③ Spatially, the water quality in the western region of Lihu Lake was significantly better than of that in the eastern region. When comparing government measures in different eutrophic urban lakes, we found that engineering management measures can improve the water quality of urban lakes over a relatively short time period. However, after the water quality has been improved, it is necessary to restore the macrophyte-dominated ecosystem, which should be supplemented by ecological restoration based on biological regulation. By improving species diversity, the aquatic ecosystem can be successfully transformed from being phytoplankton-dominated to macrophyte-dominated, thereby enabling the service functions of a lake ecosystem to be truly restored.

[Seasonal Difference in Water Quality Between Lake and Inflow/Outflow Rivers of Lake Taihu, China].

The seasonal and spatial variation of external nutrient loading from rivers and their impact on lake water quality were analyzed in Lake Taihu, China, using the monthly monitoring data from 16 major inflow/outflow rivers and 32 observation sites in the lake. The results showed:① The average monthly values of total nitrogen (TN), dissolved total nitrogen (DTN), total phosphorus (TP), and dissolved total phosphorus (DTP) in rivers were all higher than the corresponding areas in the lake. Significant positive correlations were found between nutrient concentrations in the inflow rivers and the corresponding areas in the lake, indicating the pronounced impact of external loading on lake water. ② Remarkable seasonal variations of nutrient concentration were found both in the rivers and in the lake. The highest TN and TP concentrations in inflow rivers were 4.82 mg·L-1 (March) and 0.218 mg·L-1 (December), while the highest TN and TP concentrations in the lake were 4.13 mg·L-1 and 0.255 mg·L-1 in July. ③ Extreme rainfall events could decrease the nutrient concentration in the rivers in the short-term, but finally would increase the external loading of nutrients, and indicated disadvantages for the restoration of Lake Taihu. Our study concluded that inflow pollution showed an obvious "shaping effect" on the seasonal and spatial distribution of water quality indicators in large and shallow lakes. Additionally, the self-purification ability of lakes, wind-induced accumulation and migration of algae, as well as the sediment resuspension under the prevailing winds in different seasons, all have vital effects on nutrient concentrations and their spatial-temporal variations.

[Measurement of dissolved organic nitrogen with nanofiltration pretreatment and its distribution characteristics in landscape water].

In this study, we present a nanofiltration (NF90, NF270) pretreatment to increase the precision of dissolved organic nitrogen (DON) measurements in water samples. The variations of DON measurements with and without NF pretreatment were investigated. And the effects on the removal of dissolved inorganic nitrogen (DIN) by NF90 and NF270 were compared. As shown in the results, the average removal rates reached 30.7%, 55.9% of NH4(+)-N, 50.0%, 73.1% of NO3(-) -N and 42.9%, 72.0% of NO2(-)-N for NF90 and NF270 pretreatment, respectively. NF270 was obviously more effective to remove the DIN species. Concentrations of DON measured using traditional methods varied from 0.09 to 0.46 mg x L(-1), with negative concentration (-0.08 mg x L(-1)) at site 2 and the DIN/TDN ratio ranged from 85.3% to 105%; while the concentrations of DON measurements varied from 0.03 to 0.58 mg x L(-1), and the DIN/TDN ratio ranged from 76.1% to 90.6% for NF90 pretreatment and varied from 0.10 to 0.59 mg x L(-1), and the DIN/TDN ratio ranged from 47.5% to 84.5% for NF270 pretreatment. The results indicated that nanofiltration pretreatment could effectively remove the DIN species, decrease the standard deviation of DON measurements and increase the precision of DON measurements. The distribution of DON in water samples of Beijing Olympic Forest Park was investigated. The results showed that there was seasonal variation in the concentrations of DON in landscape water from the Olympic Forest Park. And there was significant difference between the north and south part. The DON concentrations were less than 0.2 mg x L(-1) in November, March and May and higher in July in the north part, while the DON concentrations were lower in May and higher in November and March in the south part, ranging from 0.40-0.65 mg x L(-1).

Neferine increases STI571 chemosensitivity via inhibition of P-gp expression in STI571-resistant K562 cells.

We investigated the effects of neferine (Nef) on STI571 sensitivity and the possible mechanism in STI571-resistant K562/G01 cells. We observed cell proliferation by the modified MTT (methyl thiazolyl tetrazolium) assay. We determined the intracellular concentration of STI571 in K562/G01 cells by high-performance liquid chromatography (HPLC), the expression of P-glycoprotein (P-gp) by Western blotting, and the expression of MDR-1 mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR). We observed that drug resistance to STI571 for K562/G01 cells was 43.99-fold higher than that for K562 cells. We also observed that a low concentration of Nef (<8 µM) and verapamil hydrochloride (VRP) (<10 µM) showed no direct cytotoxicity but significantly reduced the 50% cell growth inhibitory concentration (IC(50)) values of STI571 in K562/G01 cells. The reverse multiples for 8 µM Nef and 10 µM VRP were approximately two-fold. Both Nef (8 µM) and VRP (10 µM) decreased MDR-1 mRNA and P-gp protein expression and increased intracellular STI57I concentrations significantly in K562/G01 cells. Nef is a candidate chemical that can increase STI571 chemosensitivity in STI571-resistant K562 cells by inhibition of P-gp expression and increasing intracellular STI571 accumulation.

A L-cysteine sensor based on Pt nanoparticles/poly(o-aminophenol) film on glassy carbon electrode.

Platinum nanoparticles (nano-Pt) and poly(o-aminophenol) (POAP) were fabricated onto the glassy carbon electrode(GCE) to form the nano-Pt/POAP/GCE for the electrochemical determination of L-cysteine. The POAP film was obtained through electrochemical polymerization of o-aminophenol on GCE. The nano-Pt was electrochemically deposited onto the surface of the activated POAP/GCE The resultant nano-Pt/POAP/GCE was characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), and showed excellent electrochemical response to L-cysteine at low oxidative potential in Britton-Robinson (BR) buffer solution (pH=3.0), with good stability and sensitivity, and featured with a low detection limit (0.08 microM, signal/noise=3) and wide linear range (0.4 microM-6.3mM).The mechanism for the electrochemical oxidation of L-cysteine on the nano-Pt/POAP/GCE was also investigated.

An amperometric horseradish peroxidase inhibition biosensor for the determination of phenylhydrazine.

An amperometric horseradish peroxidase (HRP) inhibition biosensor has been substantially constructed by the help of N,N-dicyclohexylcarbodiimide (DCC), N-hydroxysuccinimide (NHS). The preparation steps and the biosensor response to phenylhydrazine were monitored by electrochemical impedance spectroscopy (EIS), cyclic voltammetry, and chronoamperometry. The proposed biosensor could be applied to determine phenylhydrazine in a 0.10 M phosphate buffer solution containing 1.2 mM hydroquinone and 0.50 mM H(2)O(2) by phenylhydrazine, inhibiting the catalytic activity of the HRP enzyme in the reduction of H(2)O(2). The system was optimized to realize a reliable determination of phenylhydrazine in the range of 2.5 x 10(-7) to 1.1 x 10(-6) M with a detection limit of 8.2 x 10(-8) M and a correlation coefficient of 0.999. The modified electrode displayed good reproducibility, sensitivity and stability for the determination of phenylhydrazine.

Voltammetric Behavior of o-Nitrophenol and Damage to DNA.

The electrochemical behavior of o-nitrophenol was studied in detail with a glassy carbon electrode (GCE). The dependence of peak potential on pH indicated that equivalent electrons and protons were involved in the process of o-nitrophenol reduction. The interaction of o-nitrophenol with calf thymus DNA was investigated by adding DNA to the o-nitrophenol solution and by immobilizing DNA on GCE, respectively. The peak current decrement and peak potential shift in presence of DNA indicated that o-nitrophenol could interact with DNA. The result was demonstrated that the in situ DNA damage was detected by differential pulse voltammetry after the o-nitrophenol was electrochemically reduced.

Selective determination of dopamine in the presence of high concentration of ascorbic acid using nano-Au self-assembly glassy carbon electrode.

The cysteamine (CA) was bound onto surface of the pretreated glassy carbon electrode (GC) with cyclic voltammetry (CV). Gold nanoparticles were self-assembled to the electrode binding with cysteamine via strong Au-S covalent bond to fabricate the nano-Au self-assembled modified electrode (nano-Au/CA/GC). The modified electrode was characterized with cyclic voltammetric and ac impedance methods. The electrochemical behavior of dopamine (DA) on the modified electrode was investigated with cyclic voltammetry and differential pulse voltammetry (DPV). A well-defined redox peaks of DA on the nano-Au/CA/GC electrode were obtained at E(pa)=0.175 V and E(pc)=0.146 V (vs. SCE), respectively. The peak current of DA is linear with the concentration of DA in the range of 1.0 x 10(-8) mol L(-1) to 2.5 x 10(-5) mol L(-1), with the correlation coefficient of 0.998. The detection limit is 4.0 x 10(-9)mol L(-1) (S/N=3). The modified electrode exhibited an excellent reproducibility, sensibility and stability for determination of DA in the presence of high concentration AA, and can be applied to determinate dopamine injection, with satisfied result.

Electrochemical determination of trace promethazine hydrochloride by a pretreated glassy carbon electrode modified with DNA.

A highly sensitive electrochemical biosensor for the detection of trace amounts of promethazine has been designed. Double stranded (ds)DNA molecules are immobilized onto a pretreated glassy carbon electrode (GCE(ox)) surface. The voltammetric behaviors of promethazine on DNA-modified electrode were explored by means of cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The promethazine gave rise to a pair of well-defined peaks, which appeared at E(pc) = 52 mV and E(pa) = 96 mV (vs. Ag/AgCl) in 0.10 M acetate buffer (pH 5.0). The peak current was linearly enhanced with increasing the concentration of promethazine. The calibration was linear for promethazine over the range of 4.7 x 10(-10) to 9.3 x 10(-9) M with a correlation coefficient of 0.999. The limit of detection (LODs) was 3.0 x 10(-10) M (S/N = 3). The modified electrode was applied to determine promethazine in human blood samples with satisfactory results.

Direct electrochemistry behavior of cytochrome c/L-cysteine modified electrode and its electrocatalytic oxidation to nitric oxide.

Cytochrome c (Cyt c) was successfully immobilized on L-cysteine modified gold electrode by multicyclic voltammetry method. The electrochemical behavior of Cyt c on the L-cysteine modified electrode was explored. In 0.10 M, pH 7.0 phosphate buffer solution (PBS), Cyt c showed a quasi-reversible electrochemical redox behavior with E(pc)=0.180 V, E(pa)=0.208 V (versus Ag/AgCl). The Cyt c/L-cysteine modified electrode gave an excellent electrocatalytic activity towards the oxidation of nitric oxide, and the catalysis currents were proportional to the nitric oxide concentration in the range of 7.0 x 10(-7) to 1.0 x 10(-5) M, the linear regression equation is I (microA)=-0.124-0.003 C(NO) (microM), with a correlation coefficient 0.996, The detection limit was 3.0 x 10(-7) M (times the ratio of signal to noise, S/N=3).

Direct electrochemical behavior of cytochrome c on DNA-modified glassy carbon electrode and its application to cytochrome c biosensor.

DNA was immobilized on glassy carbon electrodes to fabricate DNA-modified electrodes. The direct electron transfer of horse heart cytochrome c on DNA-modified glassy carbon electrode was achieved. A pair of well-defined redox peaks of cytochrome c appeared at Epc = -0.017 V and Epa = 0.009 V (vs. Ag/AgCl) in 10 mM phosphate buffer solution (pH 7.0) at a scan rate of 50 mV/s. The electron transfer coefficient (alpha) and the standard rate constant of the surface reaction (Ks) of cytochrome c on DNA-modified electrodes could be estimated to be 0.87 and 34.52 s(-1), respectively. The DNA-modified glassy carbon electrode could be applied to detect cytochrome c by means of differential pulse voltammetry (DPV). The cathodic peak current was proportional to the quantity of cytochrome c in the range of 4.0 x 10(-6) M to 1.2 x 10(-5) M. The correlation coefficient is 0.996, and with the detection limit was 1.0 x 10(-6) M (three times the ratio of signal to noise, S/N = 3).

Potential-modulated DNA cleavage by (N-salicylideneglycinato)copper(II) complex.

The interaction of aqua (N-salicylideneglycinato)copper(II) (Cu(salgly)2+) complex with calf thymus DNA has been investigated by cyclic voltammetry. Potential-modulated DNA cleavage in the presence of Cu(salgly)2+ complex was performed at a gold electrode in a thin layer cell. DNA can be efficiently cleaved by electrochemically reducing Cu(salgly)2+ complex to Cu(salgly)+ complex at -0.7 V (vs. Ag/AgCl). When the solution was aerated with a small flow of O2 during electrolysis, the extent of DNA cleavage was dramatically enhanced, and hydroxyl radical scavengers inhibited DNA cleavage. These results suggested that O2 and hydroxyl radical were involved in potential-modulated DNA cleavage reaction. The percentage of DNA cleavage was enhanced as the working potential was shifted to more negative values and the electrolysis time was increased. It was also dependent on the ratio of Cu(salgly)2+ complex to DNA concentration. The cleaved DNA fragments were separated by high performance liquid chromatography (HPLC). The experimental results indicated that the method for potential-modulated DNA cleavage by Cu(salgly)2+ complex was simple and efficient.

Electrochemical cleavage of DNA in the presence of copper-sulfosalicylic acid complex.

Electrochemical cleavage of DNA in the presence of copper-sulfosalicylic acid [Cu(ssal)(2)(2+)] complex was studied. The cleavage was observed in a certain potential region where redox cycling of Cu(ssal)(2)(2+)/Cu(ssal)(2)(+) took place. Cu(ssal)(2)(2+) complex mediate generation of reactive oxygen species from O(2) by the Fenton reaction, these radicals are capable of damaging DNA. The cleaved DNA fragments were separated by high-performance liquid chromatography (HPLC). The experimental results indicated that the method for electrochemical cleavage of DNA by Cu(ssal)(2)(2+) complex was simple and efficient.

Determination of proteins with fullerol by a resonance light scattering technique.

Fullerol has been synthesized through the reaction of fullerene C60 with NaOH in aqueous solution by means of ultrasonic agitation and characterized by infrared and 1H-nuclear magnetic resonance spectroscopy. The fullerol obtained shows good solubility and excellent stability in water. A weak resonance light scattering (RLS) spectrum of fullerol was observed in aqueous solution. However, the intensity of the RLS signal could be enhanced in the presence of proteins, including bovine serum albumin (BSA), human serum albumin (HSA), pepsin (Pep), and lysozyme (Lys). Based on the enhancement of the RLS, a sensitive method for the determination of proteins has been established. The quantitative conditions were considered with regard to the effects of the pH, the ion strength, and the concentration of the fullerol. Under the optimum conditions, the intensity of the RLS was proportional to the concentration of proteins with the limits of detection of 9.7, 10.9, 57.4, and 8.5 ng mL(-1) for BSA, HSA, Pep, and Lys, respectively. Almost no interference can be observed from some amino acids, nucleic acids, and most of the metal ions. The model samples and human serum samples were determined satisfactorily with the proposed method.

The interaction of copper-bipyridyl complex with DNA and cleavage to DNA.

The interaction of a copper-bipyridyl (bpy) complex with CT-DNA was investigated by voltammetry, absorption and fluorescence spectrophotometry. The binding constant of the Cu(bpy)2(2+) complex interacting with DNA was 3.24 x 10(4) L/mol and the ability binding of Cu(bpy)2(2+) to DNA was 1.3-times as large as that of Cu(bpy)2+ to DNA. DNA could be efficiently cleaved by a potential-modulated method in the presence of the Cu(bpy)2(2+) complex. The fragments of the cleaved DNA were separated by high-performance liquid chromatography (HPLC). The experimental results revealed that the proposed method for DNA cleavage is highly efficient.