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Effect of curcumin on multidrug resistance in resistant human gastric carcinoma cell line SGC7901/VCR

Acta Pharmacologica Sinica 2005年第8期26卷 1009-1016页

作者： Xiao-qing TANG~1, Hu BI~1, Jian-qiang FENG~2, Jian-guo CAO~3 ~1 department of physiology, Nanhua university, Hengyang 421001, china ~2 department of physiology, zhongshan medical college, sun yat sen university, guangzhou 510080, china ~3 Institute of Oncology, Nanhua university, Hengyang 421001, china department of physiology Nanhua University Hengyang 421001 China

Aim: To investigate the reversal effects of curcumin on multidrug resistance （MDR） in a resistant human gastric carcinoma cell line. Methods: The cytotoxic effect of vincristine （VCR） was evaluated by MTT assay. The cell apoptosis induced by VCR was determined by propidium iodide （PI）-stained flow cytometry （FCM） and a morphological assay using acridine orange （AO）/ethidium bromide （EB） dual staining. P-glycoprotein （P-gp） function was demonstrated by the accumulation and efflux of rhodamine 123 （Rh123） using FCM. The expression of P-gp and the activation of caspase-3 were measured by FCM using fluorescein isothiocyanate （FITC）-conjugated anti-P-gp and anti-cleaved caspase-3 antibodies, respectively. Results: Curcumin, at concentrations of 5 μmol/L, 10 μmol/L, or 20 μmol/L, had no cytotoxic effect on a parent human gastric carcinoma cell line （SGC7901） or its VCR-resistant variant cell line （SGC7901/VCR）. The VCR-IC50value of the SGC7901/VCR cells was 45 times more than that of the SGC7901ceUs and the SGC7901/VCR cells showed apoptotic resistance to VCR. SGC7901/VCR cells treated with 5 μmol/L, 10μmol/L, or 20 μmol/L curcumin decreased the IC50value of VCR and promoted VCR-mediated apoptosis in a dose-dependent manner. Curcumin （10 μmol/L） increased Rh123 accumulation and inhibited the effiux of Rh123 in SGC7901/VCR cells, but did not change the accumulation and efflux of Rh123 in SGC7901 ceils. P-gp was overexpressed in SGC7901/VCR cells, whereas it was downregulated after a 24-h treatment with curcumin （10 μmol/L）. Resistant cells treated with 1 μmol/L VCR alone showed 77% lower levels of caspase-3 activation relative to SGC7901 cells, but the activation of caspase-3 in the resistant cell line increased by 44% when cells were treated with VCR in combination with curcumin. Conclusion: Curcumin can reverse the MDR of the human gastric carcinoma SGC7901/VCR cell line. This might be associated with decreased P-gp function and expression, and the promotion of caspase-3

关键词： curcumin multidrug resistance apoptosis P-glycoprotein caspase-3

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Temporal and Tight Hepatitis C Virus Gene Activation in Cultured Human Hepatoma Cells Mediated by a Cell-Permeable Cre Recombinase

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Acta Biochimica et Biophysica Sinica 2004年第10期36卷 687-694页

作者： Dong XIAO*, Kang XU1, Ying YUE, Zhong-Min GUO, Bing HUANG, Xin-Yan DENG, Huan TANG2, and Xi-Gu CHEN* Center of Experimental Animals, zhongshan university, guangzhou 510080, china 1The first affiliated hospital of sun yat-sen university, zhongshan university, guangzhou 510080, china 2The Third Military medical university, Chongqing 400010, china Center of Experimental Animals Zhongshan University The first affiliated hospital of sun yat-sen university Zhongshan University The Third Military medical university

Conditional gene expression has greatly facilitated the examination of the functions of particular gene products. Using the Cre/lox P switching expression system, we plan to develop efficient conditional transgeneactivation of hepatitis C virus core protein (HCV-C) cDNA (nucleotide 342–914) in the transgenic mice to overcome “immune tolerance” formed during the embryonic period and “immune escape” against hepatitis virus antigen in our project. To use this system in vivo, the dormant transgenic construct, i.e., pApoE-SCS-EGFP-HCV-C, was generated using techniques of standard molecular biology. The liver- specific human apoE promoter was here used to target expression of genes of interest (EGFP and HCV-C) to murine liver. Prior to generating the transgenic mice, the availability of Cre/lox P system and construct functionality were successfully verified by a cell-free recombination system and via checking the expression of EGFP and HCV-C in the human hepatoma cells at the mRNA and protein levels. These results suggest that the Cre/lox P system could tightly control expression of EGFP and HCV-C in vitro, which laid a solid foundation to conditionally activate expression of target gene(s) in transgenic mice by Cre-mediated site-specific recombination.

关键词： hepatitis C virus Cre/lox P switching expression system cell-free and intracellular recombination systems cell-permeable Cre recombinase EGFP human hepatoma cells

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Purification and partial characterizations of coagulant protein Fla from Daboia russelli siamensis (Myanmar) venom

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Acta Pharmacologica Sinica 2007年第10期28卷 1580-1584页

作者： Huan-huan sun~(1,3),Qi CHEN~(2,3),Xi LIN~1,Jia-shu CHEN~(1,4),Peng-xin QIU~1,Guang-mei YAN~~1 department of Pharmacology,zhongshan medical college,sun yat-sen university guangzhou 510080,china ~2 Guangdong Institute forDrug Control,guangzhou 510000,china department of Pharmacology Zhongshan Medical College Sun Yat-Sen University Guangzhou China Guangdong Institute for Drug Control Guangzhou China

Aim:To purify and characterize the coagulant protein FIa from Daboia russellisiamensis (Myanmar) ***:FIa was purified from Daboia russellisiamensis (Myanmar) venom by ion-exchange chromatography on CM-SephadexC-50,and gel filtration on Sephadex G-75 and a Superdex 75 *** hemo-static activity of FIa was determined by the method of Williams and *** chromogenic substrates were used respectively to determine the activa-tion of factor X and *** fibrinogen-clotting activity of FIa wasdetermined by the method of Gao et *** saline was used as a negativecontrol while factor Xa and thrombin were used as positive controls,***:FIa,a coagulant protein,was achieved by ion-exchange chromatogra-phy and gel filtration with a molecular weight of 34 479 and an isoelectric point *** was shown to have strong hemostatic *** hemostatic activity of0.5 mg FIa was equal to that of 1.5625 u *** primarily activated factor X,however,had no influence on prothrombin,nor did it cleave or clot ***:FIa is a factor X-activating enzyme,which could activate factor X tofactor Xa,but has no effect on prothrombin and fibrinogen.

关键词： snake venoms Daboia russelli siamensis factor X blood coagulation

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Non-invasive Prenatal Gene Diagnosis: Progress through Cell-free Fetal DNA and RNA in Maternal Plasma and Urine

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中山大学学报（医学科学版） 2008年第S2期29卷 140-142页

作者： GUO Xun-yang, GUO Yi-bin ( department of medical Genetics, zhongshan School of Medicine, sun yat-sen university, guangzhou 510080, china )

Non-invasive prenatal gene diagnosis has been developed rapidly in the recent years, and numerous medical researchers are focusing on it. Such techniques could not only achieve prenatal diagnosis accurately, but also prevent tangential illness in fetuses and thus, reduce the incidence of diseases. Moreover, it is non-invasive prenatal gene diagnosis that prevents potential threaten and danger to both mothers and fetuses. Therefore, it is welcomed by clinical gynecologist and obstetrian, researchers of medical genetics, and especially, pregnancies. This review article touches briefly on the advanced development of using cell-free DNA, RNA in maternal plasma and urine for non-invasive prenatal gene diagnosis.

关键词： non-invasive prenatal gene diagnosis cell-free fetal DNA and RNA DNA and RNA detection maternal urine maternal plasma

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Hemorrhagic activity and mechanism of FIIa,a fibrinolytic enzyme from Agkistrodon acutus venom

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Acta Pharmacologica Sinica 2004年第4期25卷 116-123页

作者： Qing-qing WANG2, Jia-shu CHEN, Xiu-xia LIANG3, Peng-xin QIU, Yi-wen WANG, Guang-mei YAN department of Pharmacology, zhongshan medical college, sun yat-sen university, guangzhou 510080, china Now in Beijing universityof Chinese Medicine,Beijing 100029,china. department of Pharmacology Zhongshan Medical College Sun Yat-Sen University

AIM: To study the local hemorrhagic activity of a fibrinolytic enzyme (FIIa) from Agkistrodon acutus venom and its mechanism. METHODS: The local hemorrhagic activity was determined by subcutaneous injection on the back of mouse. The effects of FIIa on factor X, prothrombin, gelatin, and collagen were visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Platelet aggregation assays were performed in rat platelet- rich plasma (PRP). Human umbilical vein endothelial cells (HUVEC) were cultured and passaged in complete M199 medium. Cell viability and nuclear morphology change were determined by fluorescein diacetate (FDA) staining and Hoechst 33258 staining, respectively. RESULTS: The minimum hemorrhagic dose (MHD) of FIIa was 89 μg. In vitro, FIIa (0.25 g/L) degraded factor X, prothrombin, collagen, and gelatin, and dose-dependently (0.25, 0.50, 0.75, and 1.00 g/L) inhibited the platelet aggregation induced by ADP in rat PRP. When HUVEC in culture treated with FIIa, HUVEC showed detachment in a dose-dependent manner, but no apoptosis sign was observed. CONCLUSION: FIIahad local hemorrhagic activity, and the mechanism was related to the degradation of factor X, prothrombin, gelatin, and collagen, the inhibition of ADP-induced platelet aggregation, and inducement of HUVEC detachment.2Now in Beijing universityof Chinese Medicine,Beijing 100029,china.3Correspondence to Dr Xiu-xia LIANG.

关键词： Agkistrodon acutus venom fibrinolytic enzyme hemorrhagic protease endothelial cells

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Prevention of pathological change and cognitive degeneration of Tg2576 mice by inoculating Aβ_(1-15) vaccine

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Science china(Life Sciences) 2008年第8期51卷 743-750页

作者： HU JinJia1, LI GuoYing2, WANG HuaQiao3, LIN Xian3 & YAO ZhiBin3 1 department of Anatomy, medical college of Shanghai Jiao Tong university, Shanghai 200025, china 2 department of Anatomy, Preclinical college, Guangdong university of Pharmacy, guangzhou 510006, china 3 department of Anatomy, zhongshan School of Medicine, sun yat-sen university, guangzhou 510080, china 1. department of Anatomy Medical College of Shanghai Jiao Tong University Shanghai 200025 China 2. department of Anatomy Preclinical College Guangdong University of Pharmacy Guangzhou 510006 China 3. department of Anatomy Zhongshan School of Medicine Sun Yat-sen University Guangzhou 510080 China

This study aims to discuss the effect of preventing pathological changes and cognitive degeneration of Tg2576 mice by inoculating the subunit fragment of Aβ ***-two Tg2576 mice were randomly divided into four groups, each having eight mice:Group I, the control group, inoculated with adjuvants;Group II, the Aβ42 group, inoculated with Aβ42 vaccine;Group Ⅲ, the Aβ1―15 group, inoculated with Aβ1―15 vaccine;and Group IV, the Aβ36―42 group, inoculated with Aβ36―42 *** titer of the serum anti-body against Aβ42(Group II) was significantly higher than that of the control group(Group I), and a low level of antibodies could be detected in the brain homogenate in the three vaccine-inoculated *** water maze test showed that the Aβ42 group, Aβ1―15 group and Aβ36―42 group were obviously im-proved compared with the control *** cultured splenocytes sampled from each group were induced by Con A or their respective antigens, and the cell proliferation of the three vaccine-inoculated groups was significantly higher than that of the control *** the Aβ42 group, IL2 and IFN-γ were relatively low and IL4 and IL10 were relatively *** contrast, IL4 and IL10 were much higher in the Aβ1―15 group and IL2 and IFN-γ were much higher in the Aβ36―42 *** immunohistochemical test showed a large number of senile plaques in the brain cortex and hippocampus of the mice in the con-trol group, no senile plaque in the brain of the Aβ1―15 group and Aβ42 group mice, and a small number of senile plaques in the brain of the Aβ36―42 group *** results suggest that the subunit fragment of Aβ1―15 vaccine could prevent not only cognitive and behavioral degeneration but also Aβ deposition and formation of senile plaques in Tg2576 mice.

关键词： Alzheimer’s disease β-amyloid peptide vaccine Tg2576 mice senile plaque

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Enzymological characterization of Flla,a fibrinolytic enzyme from Agkistrodon acutus venom

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Acta Pharmacologica Sinica 2005年第12期26卷 1474-1478页

作者： Xiu-xia LIANG Ying-na ZHOU Jia-shu CHEN~2 Peng-xin QIU Hui-zhen CHEN Huan-huan sun Yu-ping WU Guang-mei YAN department of Pharmacology,zhongshan medical college,sun yat-sen university,guangzhou 510080,china department of Pharmacology Zhongshan Medical College Sun Yat-Sen University Guangzhou China

Aim:To study the enzymological characterization of a fibrinolytic enzyme(FⅡa)from Agkistrodon acutus ***:The fibrinogenolytic effect and theinfluences of several protease inhibitors,chelating agents,and metal ions onfibrinogenolytic activity were visualized by sodium dodecyl sulfate-polyacryla-mide gel *** metal content of FⅡawas determined by atomicabsorption ***:After incubation with FⅡa(0.25 g/L),Aα-,Bβ-and γ-chains of fibrinogen disappeared within 5 min,30 min,and 8 h,*** molecular weights of major degradation products were 45 000 and 41 000,which were different from those bands produced by *** fibrinogenolyticactivity of FⅡawas strongly inhibited by ethylenediamine tetraacetic acid(EDTA),ethyleneglycol tetraacetic acid(EGTA),dithiothreitol and cysteine,but not byphenyhnethyl-sulfonyl fluoride and soybean trypsin ***(3171±25rag&g),potassium(489±17 mg/kg)and calcium(319±13 mg/kg)were found in FⅡ***2+,Ca2+and Mg2+could recover the fibrinogenolytic activity of FⅡa,which wasinhibited by *** Ca2+ could recover the fibrinogenolytic activity inhibitedby ***:FⅡacan degrade the Aα-,Bβ-and γ-chains of fibrinogen.FⅡais a metalloproteinase,and Zn2+,Ca2+,and disulfide bonds are necessary forits fibrinogenolytic activity.

关键词： snake venoms Agkistrodon acutus fibrinolysis metalloproteinase

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An adaptive spatial clustering method for automatic brain MR image segmentation

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Progress in Natural Science:Materials International 2009年第10期19卷 1373-1382页

作者： Jingdan Zhang,Daoqing Dai Center for Computer Vision and department of Mathematics,sun yat-sen(zhongshan) university,guangzhou 510275,china [a]Center for Computer Vision and department of Mathematics Sun Yat-Sen (Zhongshan) University Guangzhou 510275 China

In this paper,an adaptive spatial clustering method is presented for automatic brain MR image segmentation,which is based on a competitive learning algorithm-self-organizing map(SOM).We use a pattern recognition approach in terms of feature generation and classifier ***,a multi-dimensional feature vector is constructed using local spatial ***,an adaptive spatial growing hierarchical SOM(ASGHSOM) is proposed as the classifier,which is an extension of SOM,fusing multi-scale segmentation with the competitive learning clustering algorithm to overcome the problem of overlapping grey-scale intensities on boundary ***,an adaptive spatial distance is integrated with ASGHSOM,in which local spatial information is considered in the clustering process to reduce the noise effiect and the classification *** proposed method is validated by extensive experiments using both simulated and real MR data with varying noise level,and is compared with the state-of-the-art algorithms.

关键词： Self-organizing map Growing hierarchical SOM Adaptive spatial distance Image segmentation MR images

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Tetracycline-controlled transcriptional regulation systems: countermeasures to eliminate basal transgene leaks in Tet-based systems

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Progress in Natural Science:Materials International 2007年第1期17卷 11-19页

作者： XIAO Dong, sun Yan, GU Weiwang and CHEN Xigu ( Center of Experimental Animals and Institute of Comparative Medicine, Southern medical university, guangzhou 510515, china Center of Experimental Animals, sun yat-sen university, guangzhou 510080, china) [a]Center of Experimental Animals and Institute of Comparative Medicine Southern Medical University Guangzhou China [b]Center of Experimental Animals Sun Yat-sen University Guangzhou China

To analyze the function of any given transgene(s) accurately in transgenic mice, and to produce credible transgenic animal models of various human diseases (precisely and realistically mimicking disease states), it is critical to be able to control gene expression in the animals conditionally. The ability to switch gene expression "on" or "off" in the restricted cells or tissue(s) at specific time(s) allows unprecedented flexibility for exploring gene function(s) in both the health and the disease. Pioneering work on inducible transgene expression has led to the development of a wide variety of controlled gene expression systems that meet this criterion. Among them, the tetracycline-inducible systems (e.g. Tet-off and Tet-on) have been widely, frequently and successfully employed in vitro and in vivo. These systems, however, are not always tight but leaky; sometimes the leakage is significant. In some circumstances, the resulting leak is acceptable, but in others, it is more problematic. Though these systems face this disadvantage, i. e. basal transgene leakage in vitro and in vivo, several approaches, including using improved versions (e.g. rtTA2S-M2 and rtTA2S-S2) of rtTA, tetracycline-controlled transcriptional silencer (tTS), an "ideal" minimal promoter in responsive components or combinations thereof, have been developed to avoid this limitation effectively. In this review we discuss the countermeasures available to eliminate basal transgene leakage from Tet-based systems.

关键词： tetracycline inducible system transgenic mice leaky expression transcriptional silencer.

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Spontaneous chiral-symmetry breaking of lattice QCD with massless dynamical quarks

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Science china(Physics,Mechanics & Astronomy) 2007年第1期50卷 6-14页

作者： LUO XiangQian department of Physics,School of Physics and Engineering,sun yat-sen university,guangzhou 510275,china 1. department of Physics School of Physics and Engineering Sun Yat-Sen University Guangzhou 510275 China

One of the most challenging issues in QCD is the investigation of spontaneous chiral-symmetry breaking, which is characterized by the non-vanishing chiral condensate when the bare fermion mass is zero. In standard methods of the lattice gauge theory, one has to perform expensive simulations at multiple bare quark masses, and employ some modeled functions to extrapolate the data to the chiral limit. This paper applies the probability distribution function method to computing the chiral condensate in lattice QCD with massless dynamical quarks, without any ambiguous mass extrapolation. The results for staggered quarks indicate that this might be a promising and efficient method for investigating the spontaneous chiral-symmetry breaking in lattice QCD, which deserves further investigation.

关键词： lattice QCD spontaneous chiral-symmetry breaking dynamical quarks

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