| Multidrug resistance (MDR) of tumor is one of the most important factors that lead to chemotherapy failure. Establishment of the model of tumor MDR cells and research on their characteristics is significant to tumour therapy. In this paper, two models of tumour MDR were established successfully. Both their drug-resistance spectra and biological properties were analyzed. The method of affinity magnetic-bead was applied to search for the binding protein of drug in the hope of finding a new drug target. We hope that our research can be referential to clinical medicaments and supportive to mechanism of drug-resistance cell at molecule and protein level.In this thesis two lines of breast cancer cell named MCF-7/Taxola and MCF-7/Taxolb with multidrug-resistance were established by gradually increasing concentration of paclitaxel and impacting with high dose of paclitaxel for short-time from the parent cell line MCF-7 in vitro, and their biological properties including drug-resistance, cell cycle dynamics, exterior transformation, SP cells distribution and intracellular drug accumulation etc, were analyzed. Index of drug-resistance in vitro showed that the two cell lines were of good resistance to several chemotherapeutants for tumor. The IC50 of MCF-7/Taxola to Taxol was 525 times higher than that of nature MCF-7, and the the IC50 of MCF-7/Taxolb to Taxol was 330 times. The multiplication times of the two cell lines were longer than those of the nature cell . The cell cycle dynamics showed that the proportion of MCF-7 /Taxola cells in S-phase increased while those in G1-phase decreased and the proportion of MCF-7 /Taxolb was like the nature cells. The expression levels of P-gp,LRP and GSTÏ€on the cells of MCF-7/Taxola increased, and only the GSTÏ€on the cells of MCF-7 /Taxolb increased, but both ER and PR was not observed. The morphology of MCF-7/Taxola became larger and irregular, and the surface of nature cell was in the shape of floss, but MCF-7/Taxola was in the shape of bead and fluffed cotton, MCF-7 /Taxolb was the in the shape of fluffed cotton .The intracellular Taxol of MCF-7/Taxola was detected by HPLC even after 10-day culture in the medium(without Taxol), but not in MCF-7 /Taxolb.In this thesis, affinity magnetic beads method was applied to identify the binding polypeptide and protein to paclitaxel on the cell of MCF-7/S and MCF-7/Taxola. An absent strap in MCF-7/Taxola was analyzed by comparing the straps of two cell lines, which contained 25 kinds of proteins, some of which were Heat shock protein,Actinin,Dermcidin precursor,Hornerin etc. Among those kinds of proteins, two kinds were reported to be the new targets of anti-tumor drug and any research on anti-tumour resistance of the other proteins have not been reported. But there are some signal proteins among these binding proteins, and they may become the new drug-target of oncotherpay.The results indicated that both two cell lines were typical multidrug-resistant cell lines which have basic characteristics of drug resistance cells. These two cell models are helpful to research on the MDR mechanism of cancer cells. By comparing the two cell lines, it is possible that the MCF-7/Taxolb was a subpopulation of MCF-7/Taxola. It was supposed that there are a large number of cancer stem cells existed in MCF-7 /Taxolb model. |
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