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Aim To investigate the effect of exposure to high or low concentration chemotherapeutic drugs on multidrug resistance of human breast cancer cell MDA-MB-231.Method MDA-MB-231 was treated with high dose of adriamycin and paclitaxel or with low concentration of paclitaxe.SRB assay was used to determine the IC50 and RF.HE assay was used to evaluate the cellular morphology.The variations of P-gp and MDR1 were analyzed by immunocytochemistry and RT-PCR respectively.Results Cells survived only after treated with high dose of paclitaxel (MDA-MB-231/a).SRB assay showed that the growth rate of MDA-MB-231/a was the same as that of parent MDA-MB-231/w.The IC50 of the cells(MDA-MB-231/b)treated with low concentration of paclitaxel to several chemotherapeutic drugs was a little higher than that of MDA-MB-231/w.Immunocytochemistry showed that there was no difference between MDA-MB-231/a and MDA-MB-231/w in the expression of P-gp while the P-gp expression was a little higher in MDA-MB-231/b.RT-PCR assay showed that the MDR1 gene was over-expressed in MDA-MB-231/b.Conclusions The multidrug resistance cell lines can not be derived from MDA-MB-231/w by high dose of chemotherapeutic drugs.Induction of multidrug resistance response to chemotherapeutic drugs is related with transient exposure to low concentration of paclitaxel and this may be a way to establish the multidrug resistance model of MDA-MB-231 cells.
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Aim To study the mutidrugresistance mechanism of tumor cell by comparing the binding pro-tein with Adriamycin(ADM)in the MCF-7/Wild cell and MCF-7/ADM resistance cell.Methods The biotin-ADM compound was synthesized with the esterification-dehydration method,purified with HPLC and analyzed with mass spectrograph.The binding proteins against Adriamycin from MCF-7/ADM or MCF-7/Wild cell whose resistance index is above 200 were obtained respectively by the affinity screening magnetism bead method with biotin-ADM compound as a specific ligand.Some binding proteins with Adriamycin were identified with the MALDI-TOF-MS after isolating them with SDS-PAGE.Cell motor ability was compared in the migration experiment.Results The variability of biotin-ADM and ADM was negligible,while that IC50 of the two compounds to MCF-7/Wild was 0.796 ?mol?L-1 and 0.547 ?mol?L-1 respectively.The 20 types binding proteins with ADM were found from MCF-7/Wild cell,and 17 types binding proteins from MCF-7/ADM resistance cell.There was one protein band difference from the two cells on SDS-PAGE with silver staining.The same binding proteins on the two cells that identified with MALDI-TOF-MS were myosin,beta-actin,alpha-actin,keratin.MCF-7/W and MCF-7/ADM both migrated after being cultivated 72 h,with a faster migration of MCF-7/ADM.Conclusion There are different binding protein with ADM on the MCF-7/Wild cell and MCF-7/ADM resistance cell.The same binding protein with ADM on the two cells belongs to the cystoskeleton protein.The binding of the ADM with the cell cystoskeleton protein has some effect to the migration of the MCF-7/ADM.
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Aim To investigate the specificity of angiostatin to vascular endothelial cells. Methods S-180 tumor imaging and autoradiography of angiogenesis on Matrigel model was developed with 99 Tcm-recombinant human angiostatin ( 99 Tcm-rhAS) as a tracer, and FCM on human microvascular endothelial cell-1 (HMEC-1) with FITC-rhAS or rhAS antibody. The binding protein of rhAS on HMEC-1 was isolated by af-finity chromatography, and the proteins was sequenced with MS. Results 99 Tcm-rhAS was concentrated on the tumor site in vivo, and the rhAS was specific to angiogenesis of tumor. There were some binding sites on the surface of HMEC-1. Three proteins which are able to bind rhAS were obtained by affinity chromatography, among which tubulin sequenced was an important target for tumor. Conclusion The angiostatin is specific to novel vascular endothelial cell, and its mechanism targeting tumor is complicated.
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Aim To establish a new paclitaxel resistant human mammary adenocarcinoma cell subline(MCF-7/Taxol) and investigate its characteristics.Methods A paclitaxel resistant human mammary adenocarcinoma cell subline(MCF-7/Taxol) was developed by gradually increasing the concentration of Taxol from the parent cell line MCF-7 in vitro.The multidrug resistance of MCF-7/Taxol to anticancer agents was evaluated by SRB assay;the distribution of their cell cycles was detected by flow cytometry;the positive expression rate of P-gP、LRP、ToPoII、GST?、ER and PR was measured by S-P immunohistochemistry;the intracellular accumulation of Taxol was assessed by HPLC;the morphological features and the celluar ultrastructure characteristics were observed respectively by light microscopy and scanning electron microscopy.Results MCF-7/Taxol was resistant to several chemotherapy agents,such as Hydroxycamptothecine,Epirubicin,Doxorubicin,Mitoxantone and so on.The IC50 of MCF-7/Taxol to Taxol was 525 times higher than that of MCF-7,and the IC50 of MCF-7/Taxol stopped administrating Taxol for three months was 150 times higher than that of MCF-7.The multiplication time of MCF-7/Taxol was longer than that of the natural cell and the proportion of cells in S-phase increased while that in G1-phase decreased.The expression levels of P-gp、LRP and GST? increased,and ER and PR were not observed.The morphology of MCF-7/Taxol became larger and irregular,and the surface of natural cell was in the shape of floss,but MCF-7/Taxol was in the shape of bead.The intracellular of Taxol was observed in both MCF-7/Taxol and stoppage administrating.Conclusions MCF-7/Taxol cell subline was a typical multidrug resistant cell line which had basic characteristics of drug resistance cells.It was supposed that there was a cell subline which was tumor stem cell of MCF-7 included in this multidrug resistant cell line.
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0.990).The intra-assay and inter-assay variation of the method was 3.10 % and 4.93 %,respectively.The all-trans ratinoic acid(ATRA) up-regulated t-PA mRNA expression in a dose-dependent manner(1.25~20.00 ?mol?L~(-1),P