In order to enhance the efficiency and specificity of anticancer drug delivery and realize intelligently controlled release,a new multi-functional nanoparticle drug carrier was synthesized.The drug carrier was prepare...In order to enhance the efficiency and specificity of anticancer drug delivery and realize intelligently controlled release,a new multi-functional nanoparticle drug carrier was synthesized.The drug carrier was prepared by functionalizing multi-walled carbon nanotubes(MWCNTs) with polyethylenimines(PEI),fluorescein isothiocyanate(FITC) and glycyrrhizic acid(GL).After detailed characterization,doxorubicin(DOX) was loaded onto the obtained MWCNT composites through π-π stacking interactions.The drug loading capacity of the GL-functionalized material was up to 92%,and the release behavior was significantly pH-sensitive.Release at pH = 5.8(typical of the tumor cell microenvironment) was much more rapid and reached a greater extent than release under normal physiological conditions(pH = 7.4).The modified MWCNTs had high biocompatibility with the liver cancer cell line SMMC-7721,but were able to induce cell death after 24 h incubation if loaded with DOX.Tests with shorter incubation time(2 h) were undertaken to investigate the selectivity of the MWCNT composites,showed that the nanocomposites could specifically target cancer cells.The above results suggest that the functionalized carbon nanotubes-based material has potential applications for targeted delivery and controlled release of anticancer drug.展开更多
In the cultivation of gene engineered strain of Escherichia coli on glucose medium, excretion and accumulation of acetic acid inhibit not only cell growth but also the the expression of heterologous protein. It is obv...In the cultivation of gene engineered strain of Escherichia coli on glucose medium, excretion and accumulation of acetic acid inhibit not only cell growth but also the the expression of heterologous protein. It is obvious that the desirable host strain maintaining acetate at a low level is one of the approaches to increase the production of recombinant protein. The present article deals with the selection of mutants of E.coli DP19, DP8, which grow on the medium containing pyruvate as the sole carbon source in the presence of 50mmol/L fluoroacetic acid. It is shown that mutant DP19 is defective in its phosphotransacetylase(PTA)activity and accumulates less acetate in the medium, while DP8 is defective in acetate kinase (ACK)and accumulates similar level of acetate comparing with its parent. Using pta - mutant E.coli DP19 as host, the expression of GL 7ACA acylase gene on the recombinant plasmid pMR24 is improved, and the yield of enzyme activity in flask fermentation is about twice as much as its parent.展开更多
[目的]探讨MUC16蛋白的硫酸化O型连接糖对食管鳞癌细胞的迁移作用。[方法]TCGA数据库分析MUC16在食管癌组织中的表达水平。过表达或敲低MUC16后,划痕实验检测食管鳞癌细胞KYSE-30的迁移水平。过表达或敲低CHST4后,Lectin blot和Alcian b...[目的]探讨MUC16蛋白的硫酸化O型连接糖对食管鳞癌细胞的迁移作用。[方法]TCGA数据库分析MUC16在食管癌组织中的表达水平。过表达或敲低MUC16后,划痕实验检测食管鳞癌细胞KYSE-30的迁移水平。过表达或敲低CHST4后,Lectin blot和Alcian blue染色检测食管鳞癌细胞中MUC16的O型连接糖硫酸化水平以及食管鳞癌细胞的迁移水平,LC-ESI-MS检测MUC16的O型连接糖类型。[结果]相比于食管正常组织,食管癌组织中MUC16和CHST4的表达水平较高(0.78±0.13 vs 0.09±0.02;0.43±0.08 vs 0.07±0.02,P<0.05)。过表达MUC16后,食管鳞癌细胞的迁移水平显著上升;敲低MUC16后,食管鳞癌细胞的迁移水平显著下降。敲低CHST4后,MUC16 O型连接糖的硫酸化水平显著下降,食管鳞癌细胞的迁移水平显著下降;过表达CHST4后,MUC16 O型连接糖的硫酸化水平显著上升,食管鳞癌细胞的迁移水平显著上升。食管鳞癌细胞在m/z 813和1121处发现了含有GlcNAc-6-O-硫酸的低聚糖,而敲低CHST4后硫酸化的低聚糖水平降低。[结论]CHST4介导的MUC16蛋白O型连接糖硫酸化对食管鳞癌细胞的迁移具有促进作用(1.00±0.05 vs 1.83±0.12)。展开更多
基金Science and Technology Commission of Shanghai Municipality,China(No.16410723700)"111 Project" Biomedical Textile Materials Science and Technology,China(No.B07024)the UK-China Joint Laboratory for Therapeutic Textiles
文摘In order to enhance the efficiency and specificity of anticancer drug delivery and realize intelligently controlled release,a new multi-functional nanoparticle drug carrier was synthesized.The drug carrier was prepared by functionalizing multi-walled carbon nanotubes(MWCNTs) with polyethylenimines(PEI),fluorescein isothiocyanate(FITC) and glycyrrhizic acid(GL).After detailed characterization,doxorubicin(DOX) was loaded onto the obtained MWCNT composites through π-π stacking interactions.The drug loading capacity of the GL-functionalized material was up to 92%,and the release behavior was significantly pH-sensitive.Release at pH = 5.8(typical of the tumor cell microenvironment) was much more rapid and reached a greater extent than release under normal physiological conditions(pH = 7.4).The modified MWCNTs had high biocompatibility with the liver cancer cell line SMMC-7721,but were able to induce cell death after 24 h incubation if loaded with DOX.Tests with shorter incubation time(2 h) were undertaken to investigate the selectivity of the MWCNT composites,showed that the nanocomposites could specifically target cancer cells.The above results suggest that the functionalized carbon nanotubes-based material has potential applications for targeted delivery and controlled release of anticancer drug.
文摘In the cultivation of gene engineered strain of Escherichia coli on glucose medium, excretion and accumulation of acetic acid inhibit not only cell growth but also the the expression of heterologous protein. It is obvious that the desirable host strain maintaining acetate at a low level is one of the approaches to increase the production of recombinant protein. The present article deals with the selection of mutants of E.coli DP19, DP8, which grow on the medium containing pyruvate as the sole carbon source in the presence of 50mmol/L fluoroacetic acid. It is shown that mutant DP19 is defective in its phosphotransacetylase(PTA)activity and accumulates less acetate in the medium, while DP8 is defective in acetate kinase (ACK)and accumulates similar level of acetate comparing with its parent. Using pta - mutant E.coli DP19 as host, the expression of GL 7ACA acylase gene on the recombinant plasmid pMR24 is improved, and the yield of enzyme activity in flask fermentation is about twice as much as its parent.
文摘[目的]探讨MUC16蛋白的硫酸化O型连接糖对食管鳞癌细胞的迁移作用。[方法]TCGA数据库分析MUC16在食管癌组织中的表达水平。过表达或敲低MUC16后,划痕实验检测食管鳞癌细胞KYSE-30的迁移水平。过表达或敲低CHST4后,Lectin blot和Alcian blue染色检测食管鳞癌细胞中MUC16的O型连接糖硫酸化水平以及食管鳞癌细胞的迁移水平,LC-ESI-MS检测MUC16的O型连接糖类型。[结果]相比于食管正常组织,食管癌组织中MUC16和CHST4的表达水平较高(0.78±0.13 vs 0.09±0.02;0.43±0.08 vs 0.07±0.02,P<0.05)。过表达MUC16后,食管鳞癌细胞的迁移水平显著上升;敲低MUC16后,食管鳞癌细胞的迁移水平显著下降。敲低CHST4后,MUC16 O型连接糖的硫酸化水平显著下降,食管鳞癌细胞的迁移水平显著下降;过表达CHST4后,MUC16 O型连接糖的硫酸化水平显著上升,食管鳞癌细胞的迁移水平显著上升。食管鳞癌细胞在m/z 813和1121处发现了含有GlcNAc-6-O-硫酸的低聚糖,而敲低CHST4后硫酸化的低聚糖水平降低。[结论]CHST4介导的MUC16蛋白O型连接糖硫酸化对食管鳞癌细胞的迁移具有促进作用(1.00±0.05 vs 1.83±0.12)。
