OBJECTIVE To investigate the influence of O-(4-ethoxyl-butyl)- berbamine(EBB)on the expression of cyclin B1 and cdc2-p34 in the human drug-resistant breast cancer MCF-7/ADR cell line. METHODS The MTT assay was used to...OBJECTIVE To investigate the influence of O-(4-ethoxyl-butyl)- berbamine(EBB)on the expression of cyclin B1 and cdc2-p34 in the human drug-resistant breast cancer MCF-7/ADR cell line. METHODS The MTT assay was used to assess the cytotoxicity of EBB.Different levels of EBB were added to different cell lines at series of time points solely or combined with doxorubicin(DOX) to detect the effect on the expression of cyclinB1 and cdc2-p34 by Western blots.cdc2-p34 tyrosine phosphorylation was detected by immunoprecipitation.In addition,apoptosis and cytoplastic Ca 2+ concentrations were systematically examined by laser scanning confocal microscopy(LSCM). RESULTS EBB showed little inhibitory activity on human umbilical vein endothelial cells(ECV304),whereas EBB inhibited cell growth(IC50 range,4.55~15.74μmol/L)in a variety of sensitive and drug-resistance cell lines.EBB also down-regulated the expression of cyclin B1 and cdc2-p34 in a concentration and time dependent manner,which was an important reason for the G2/M phase arrest.EBB was shown to induce apoptosis of MCF-7/ADR cells while increasing the level of cytoplastic Ca 2+ . CONCLUSION The low cytotoxicity of EBB suggests it may be useful as a rational reversal agent.The effect of EBB on cell cycle arrest and related proteins,apoptosis,and cytoplastic Ca 2+ concentration may be involved in reversing multidrug resistance.展开更多
Objective: Radiotherapy has been widely used to treat lung cancer. However, non-small lung cancer cells are insensitive to radiation, diminishing their radiotherapy effects. Although the radiosensitivity of the non-sm...Objective: Radiotherapy has been widely used to treat lung cancer. However, non-small lung cancer cells are insensitive to radiation, diminishing their radiotherapy effects. Although the radiosensitivity of the non-small lung cancer cells was reported to be enhanced through regulating miR-34a, the regulation effects of miR-34a expression on radiosensitivity of lung adenocarcinoma cells through target genes CDK4, CDK6, CyclinD1, and Bcl-2/Bax have not been systematically investigated. Methods: In this study, we investigated the effect of miR-34a expression on the Bcl-2, CDK4, and CDK6 pathways in lung adenocarcinoma cells, to provide new insights into the sensitization treatment of lung cancer. We first studied the effect of miR-34a expression on H1299 and A549 cell activity. Then to investigate the mechanisms of radiosensitivity, we focused on apoptosis, cell cycle, and target genes. Results: We find that overexpression of miR-34a in lung adenocarcinoma cells inhibits cell activity, and improves radiosensitivity. Specifically, overexpression of miR-34a suppresses the expression of target genes CDK4, CDK6, CyclinD1, and Bcl-2/Bax, which leads to cell cycle arrest and promotes apoptosis of lung adenocarcinoma cells. Conclusions: Overall, our results demonstrate that the overexpression of miR-34a enhances the radiosensitivity of lung adenocarcinoma cells, indicating that miR-34a is a sensitizer for lung adenocarcinoma radiotherapy.展开更多
In this paper we study some equivariant systems on the plane. We first give some criteria for the outer or inner stability of compound cycles of these systems. Then we investigate the number of limit cycles which appe...In this paper we study some equivariant systems on the plane. We first give some criteria for the outer or inner stability of compound cycles of these systems. Then we investigate the number of limit cycles which appear near a compound cycle of a Hamiltonian equivariant system under equivariant perturbations. In the last part of the paper we present an application of our general theory to show that a Z3 equivariant system can have 13 limit cycles.展开更多
This paper concerns the number and distributions of limit cycles in a Z 2-equivariant quintic planar vector field. 25 limit cycles are found in this special planar polynomial system and four different configurations o...This paper concerns the number and distributions of limit cycles in a Z 2-equivariant quintic planar vector field. 25 limit cycles are found in this special planar polynomial system and four different configurations of these limit cycles are also given by using the methods of the bifurcation theory and the qualitative analysis of the differential equation. It can be concluded that H(5) ? 25 = 52, where H(5) is the Hilbert number for quintic polynomial systems. The results obtained are useful to study the weakened 16th Hilbert problem.展开更多
Objective： To learn the effect of allitridi on inducing mitotic arrest in human gastric cell line SGC-7901 and its possible mechanisms. Methods： We treated SGC-7901 cells with allitridi, and observed the proliferati...Objective： To learn the effect of allitridi on inducing mitotic arrest in human gastric cell line SGC-7901 and its possible mechanisms. Methods： We treated SGC-7901 cells with allitridi, and observed the proliferation inhibitory rate with MTT colometric assay, changes of cell cycle using flow cytometry and Switzerland-Giemsa＇s staining, and morphologic changes of the microtubule structure and location changes of cyclin BI expression using immunofluorescence and confocal laser scanning microscope. Furthermore, the expression of cyclin B1 was analyzed quantitatively using Leica confocal software. Results： SGC-7901 cells were inhibited after exposure to allitridi and the IC50 was 7.2μg/ml for 24 h, 20μg/ml for 72 h. When the cells were treated with allitridi at concentrations of 3, 6, and 9μg/ml for 24 h respectively, there was a declining tendency in the percentage of G0/G1 cell but an increasing tendency in GE/M cell in the allitridi treated group compared with that of control （P〈0.01）. When cells were treated allitridi at concentration of 6 μg/ml for 24 h, its mitotic index was much higher （P〈0.01） than that of control, suggesting that allitridi caused arrest of gastric cancer cells in M phase. The cells were treated with allitridi became more shrunken and nepheloid, in which the microtubule networks disappeared, while the control cell exhibited an intact microtubule network. Contrasting with normal existence mainly in the cytoplasm, the cyclin B1 was expressed more significantly and concentrated in the nucleus after exposure to allitridi. Fluorescence intensity of cyclin B 1 protein in cells treated with allitridi was much more higher than that of control （P〈0.001）. Conclusion： Allitridican induce arrest of SGC-7901 cells in M phase, probably through enhancing microtubule depolymerization by elevating the expression of cyclin B1.展开更多
The fluorescent calcium ion indicator dye Fluo-3 and DNA-binding dye Hoechst 33342 were employed to determine, in a quantitative microspectrofluorometric study, the intracellular calcium ion concentration ([Ca^(2+)]_i...The fluorescent calcium ion indicator dye Fluo-3 and DNA-binding dye Hoechst 33342 were employed to determine, in a quantitative microspectrofluorometric study, the intracellular calcium ion concentration ([Ca^(2+)]_i) and the DNA content of individual living NIH3T3 cells. The well-separated excitation and emission properties of these dyes allowed us to establish for each cell both the phase of the cell cycle using DNA content and [Ca^(2+)]_i. We found that the transition from G_1, through S, to the G_2 phase is accompanied by a two-fold increase in [Ca^(2+)]_i. The [Ca^(2+)]_i was inhomologous in each phase of the interphase (G_1, S and G_2) although [Ca^(2+)]_i in the S and G_2 phases was never lower than certain threshold values in the G_1 and S phases respectively. [Ca^(2+)]_i in G_0 cells was lower than that in G_2 cells. These changes in [Ca^(2+)]_i suggest that [Ca^(2+)]_i may be an import regulator of cell cycle progression.展开更多
基金This work was supported by grants from the National Nature Science Foundation of China(No.30572203,30570772)the Key Fund of Science of TianJin Municipal Government(No.07JCZDJC04900)
文摘OBJECTIVE To investigate the influence of O-(4-ethoxyl-butyl)- berbamine(EBB)on the expression of cyclin B1 and cdc2-p34 in the human drug-resistant breast cancer MCF-7/ADR cell line. METHODS The MTT assay was used to assess the cytotoxicity of EBB.Different levels of EBB were added to different cell lines at series of time points solely or combined with doxorubicin(DOX) to detect the effect on the expression of cyclinB1 and cdc2-p34 by Western blots.cdc2-p34 tyrosine phosphorylation was detected by immunoprecipitation.In addition,apoptosis and cytoplastic Ca 2+ concentrations were systematically examined by laser scanning confocal microscopy(LSCM). RESULTS EBB showed little inhibitory activity on human umbilical vein endothelial cells(ECV304),whereas EBB inhibited cell growth(IC50 range,4.55~15.74μmol/L)in a variety of sensitive and drug-resistance cell lines.EBB also down-regulated the expression of cyclin B1 and cdc2-p34 in a concentration and time dependent manner,which was an important reason for the G2/M phase arrest.EBB was shown to induce apoptosis of MCF-7/ADR cells while increasing the level of cytoplastic Ca 2+ . CONCLUSION The low cytotoxicity of EBB suggests it may be useful as a rational reversal agent.The effect of EBB on cell cycle arrest and related proteins,apoptosis,and cytoplastic Ca 2+ concentration may be involved in reversing multidrug resistance.
文摘Objective: Radiotherapy has been widely used to treat lung cancer. However, non-small lung cancer cells are insensitive to radiation, diminishing their radiotherapy effects. Although the radiosensitivity of the non-small lung cancer cells was reported to be enhanced through regulating miR-34a, the regulation effects of miR-34a expression on radiosensitivity of lung adenocarcinoma cells through target genes CDK4, CDK6, CyclinD1, and Bcl-2/Bax have not been systematically investigated. Methods: In this study, we investigated the effect of miR-34a expression on the Bcl-2, CDK4, and CDK6 pathways in lung adenocarcinoma cells, to provide new insights into the sensitization treatment of lung cancer. We first studied the effect of miR-34a expression on H1299 and A549 cell activity. Then to investigate the mechanisms of radiosensitivity, we focused on apoptosis, cell cycle, and target genes. Results: We find that overexpression of miR-34a in lung adenocarcinoma cells inhibits cell activity, and improves radiosensitivity. Specifically, overexpression of miR-34a suppresses the expression of target genes CDK4, CDK6, CyclinD1, and Bcl-2/Bax, which leads to cell cycle arrest and promotes apoptosis of lung adenocarcinoma cells. Conclusions: Overall, our results demonstrate that the overexpression of miR-34a enhances the radiosensitivity of lung adenocarcinoma cells, indicating that miR-34a is a sensitizer for lung adenocarcinoma radiotherapy.
基金The work was supported by the National Natural Science Foundation of China (Grant No. 10671127)Program for New Century Excellent Talents in University (Grant No. NCET-04-0388)
文摘In this paper we study some equivariant systems on the plane. We first give some criteria for the outer or inner stability of compound cycles of these systems. Then we investigate the number of limit cycles which appear near a compound cycle of a Hamiltonian equivariant system under equivariant perturbations. In the last part of the paper we present an application of our general theory to show that a Z3 equivariant system can have 13 limit cycles.
基金Supported by the Fund of Youth of Jiangsu University(Grant No.05JDG011)the National Natural Science Foundation of China(Nos.90610031,10671127)+1 种基金the Outstanding Personnel Program in Six Fields of Jiangsu Province(Grant No.6-A-029)Shanghai Shuguang Genzong Project(Grant No.04SGG05)
文摘This paper concerns the number and distributions of limit cycles in a Z 2-equivariant quintic planar vector field. 25 limit cycles are found in this special planar polynomial system and four different configurations of these limit cycles are also given by using the methods of the bifurcation theory and the qualitative analysis of the differential equation. It can be concluded that H(5) ? 25 = 52, where H(5) is the Hilbert number for quintic polynomial systems. The results obtained are useful to study the weakened 16th Hilbert problem.
基金the National 10th Five-year Plan Key Technologies R & D Program of China(No.2004BA703B04-02)
文摘Objective： To learn the effect of allitridi on inducing mitotic arrest in human gastric cell line SGC-7901 and its possible mechanisms. Methods： We treated SGC-7901 cells with allitridi, and observed the proliferation inhibitory rate with MTT colometric assay, changes of cell cycle using flow cytometry and Switzerland-Giemsa＇s staining, and morphologic changes of the microtubule structure and location changes of cyclin BI expression using immunofluorescence and confocal laser scanning microscope. Furthermore, the expression of cyclin B1 was analyzed quantitatively using Leica confocal software. Results： SGC-7901 cells were inhibited after exposure to allitridi and the IC50 was 7.2μg/ml for 24 h, 20μg/ml for 72 h. When the cells were treated with allitridi at concentrations of 3, 6, and 9μg/ml for 24 h respectively, there was a declining tendency in the percentage of G0/G1 cell but an increasing tendency in GE/M cell in the allitridi treated group compared with that of control （P〈0.01）. When cells were treated allitridi at concentration of 6 μg/ml for 24 h, its mitotic index was much higher （P〈0.01） than that of control, suggesting that allitridi caused arrest of gastric cancer cells in M phase. The cells were treated with allitridi became more shrunken and nepheloid, in which the microtubule networks disappeared, while the control cell exhibited an intact microtubule network. Contrasting with normal existence mainly in the cytoplasm, the cyclin B1 was expressed more significantly and concentrated in the nucleus after exposure to allitridi. Fluorescence intensity of cyclin B 1 protein in cells treated with allitridi was much more higher than that of control （P〈0.001）. Conclusion： Allitridican induce arrest of SGC-7901 cells in M phase, probably through enhancing microtubule depolymerization by elevating the expression of cyclin B1.
文摘The fluorescent calcium ion indicator dye Fluo-3 and DNA-binding dye Hoechst 33342 were employed to determine, in a quantitative microspectrofluorometric study, the intracellular calcium ion concentration ([Ca^(2+)]_i) and the DNA content of individual living NIH3T3 cells. The well-separated excitation and emission properties of these dyes allowed us to establish for each cell both the phase of the cell cycle using DNA content and [Ca^(2+)]_i. We found that the transition from G_1, through S, to the G_2 phase is accompanied by a two-fold increase in [Ca^(2+)]_i. The [Ca^(2+)]_i was inhomologous in each phase of the interphase (G_1, S and G_2) although [Ca^(2+)]_i in the S and G_2 phases was never lower than certain threshold values in the G_1 and S phases respectively. [Ca^(2+)]_i in G_0 cells was lower than that in G_2 cells. These changes in [Ca^(2+)]_i suggest that [Ca^(2+)]_i may be an import regulator of cell cycle progression.
