Objective To explore the effect of voltage-gated sodium channels(VGSCs) on metabasis behavior of human breast cancer cell lines MDA-MB-231 and MCF-7.MethodsRT-PCR,Western blot,MTT and Transwell assays were respectively used to detect the expression of VGSCs and the effect of specific VGSCs inhibitor TTX on cell toxicity,and migration and invasion of MDA-MB-231 and MCF-7 cells.ResultsNav1.1,Nav1.4 and Nav1.8 were over-expressed in MDA-MB-231 and MCF-7 cells.The expression levels of Nav1.3,Nav1.5 and Nav1.6 mRNA in MDA-MB-231 cells were higher than in MCF-7 cells,especially Nav1.5 had the functional protein expression.After treatment with 1 and 30 μmol/L TTX in vitro,the invasive capacities of MDA-MB-231 cells were decreased(12.50±0.19)% and(53.58±1.03)% respectively,while those of MCF-7 cells had no obvious changes.ConclusionNaV1.5 was over-expressed in MDA-MB-231 cells,and TTX could reduce their invasive behaviors by inhibiting the activity of VGSCs.

Objective:To explore the effect of endostatin plasmid combined with cisplatin on the proliferation and apoptosis of human ovarian cancer cell line A2780.Methods:After the transfection of endostatin plasmid into A2780 cells,MTT and flow cytometry were used to detect the effects of endostatin or endostatin+cisplatin on the proliferation and apoptosis of A2780 cells.Results:MTT assay revealed that the inhibition of cisplatin to the growth of A2780 cells transfected with endostatin plasmid was significantly enhanced,compared with control group,the proliferation reduced significantly (P<0.05).The flow cytometry revealed that after transfection of endostatin plasmid into A2780 cells,compared with control group,the apoptosis rate increased from (1.59±0.86)% to (8.66±1.27)%,and the G0/G1 stage cell rate increased significantly,the S stage cell rate reduced sharply and apoptosis rate increased significantly (P<0.05).In addition,after combined use of endostatin plasmid and cisplatin,all the changes were more significant (P<0.01).Conclusion:Endostatin can effectively inhibit the growth and promote the apoptosis of ovarian cancer cell lines A2780,combined endostatin with cisplatin have synergic effect on anti-ovarian cancer therapeutics.

Objective:To investigate cell apoptosis by silencing MDR1 and MDR3 gene on Paclitaxel resistant A2780 /Taxol cell line.Methods:siRNA plasmids targeting MDR1 and MDR3 were transfected to A2780 /Taxol cell.MTT assay,flow cytometry,immunofluorescence,and Western blot were respectively used to detect the cell sensitivity to Paclitaxel,apoptosis and cell cycle,activity of caspase3,expression of P-gp.Results:After treatment with MDR1 and MDR3 siRNA plasmid vectors,the relative reversal efficiency of A2780 /Taxol cells to Paclitaxel for two siRNA were 64.3 % and 53.9%,respectively;the apoptosis rates were increased from 1.59% to 9.43%,and 8.66%;the activity of caspase-3 was increased and the expression of P-gp protein were significantly descended,there were significantly difference when compared with control group(P0.05).Conclusions:siRNA MDR1 and siRNA MDR3 transfection may improve sensitivity of A2780/Taxol cells to Paclitaxel by inducing apoptosis and reverse cell resistance to Paclitaxel.

Objective To investigate the effect of gene silence of MDR1 gene by small interference RNA( siRNA) in drug resistant A2780/Taxol cell line. Methods From July 2005 to December 2005,two siRNAs which were specifically targeted MDR1(Multidrug resistance 1) gene were synthesized by Union Hospital of Tongji Medical Schod, then the plasmid was transformed into E.coli. From positive clone, the plasmid was obtained and purified.The purified plasmid was co-transfected with pEGFPN-1 plasmid into A2780/Taxol cells. The positive expression of transfection was determined by the flow cytometry (FCM).50% inhibition concentration (IC_ 50 ) of paclitaxel on A2780/Taxol was determined by MTT method in vitro. P-gp protein was detected by Western blot. MDR1 mRNA was assessed by RT-PCR. Results The transfection efficiency had no difference between the two constitutive plasmids and the EGFP plasmid. The relative reversal efficiency of A2780/Taxol cells to paclixtel for two siRNA was 63.8 % and 51.2% respectively. The expression of p-gp decreased greatly. Treatment of A2780/Taxol cell with the 2 kinds of siRNAs resulted in a silence of MDR1 gene to different extent. The MDR-A siRNA was more effective in the suppression of MDR1 with a significant reduction of (67.3±0.8)% of the MDR1 mRNA expression. Conclusion The siRNA can effectively reverse the MDR1/P-gp-mediated multidrug resistance of A2780/Taxol cells.

To explore the role and possible mechanism of apoptosis and caspase-3 activity in the development of multicellular drug resistance of ovary cancer. Ovarian cancer cell A2780 multicellular spheroids (MCS) were obtained from three-dimensional culture. Drug sensitivity of monolayer cells (MC) and MCS were respectively tested by MTT staining and cytometry. The apoptosis of MC and MCS were determined by the flow cytometry (FCM). The expression of bcl-2 and caspase-3 in A2780/MC and A2780/MCS were detected by using Western blot and caspase-3 assay kit. A2780/MC was compacted into mass after 2 days in three-dimensional cell culture model, and MCS had more than two layers of cells growing within 5 days. Compared with A2780/MC, A2780/MCS were more resistant to the anticancer drug, and the apoptosis rate was significantly lower than those of A2780/MC. The activity of caspase-3 in A2780/MCS was significantly lower than the A2780/MC. But the expression of bcl-2 in A2780/MCS was significantly higher than that in A2780/MC. It was suggested that the drug resistance of MCS might be associated with the overexpression of anti-apoptosis protein bcl-2 and the down-regulation of caspase-3 activity.