Development of rational in vitro models for drug resistance in breast cancer and modulation of MDR by selected compounds

Kars, Meltem Demirel
Iseri, Ozlem Darcansoy
Gündüz, Ufuk
Ural, Adi Ugur
Arpaci, Fikret
Molnar, Jozsef
Backgroud: The effectiveness of chemotherapy is limited by the emergence of multidrug resistance (MDR). MDR is caused by the activity of various ATP binding cassette (ABC) transporters that pump anticancer drugs out of the cells in an ATP-dependent manner. Additionally some other cellular mechanisms of MDR have been reported. The purpose of this study was to investigate mechanisms of MDR in drug resistant MCF-7 cell lines and to modulate P-glycoprotein (P-gp) and MRP1-based MDR. Materials and Methods: Paclitaxel (MCF-7/Pac), docetaxel (MCF-7/Doc), doxorubicin (MCF-7/Dox) and vincristine (MCF-7/Vinc) resistant sublines were developed from the parent MCF-7 cell line (MCF-7/S) by stepwise selection in dose increments over two years. Flow cytometry, MTT cytotoxicity assay, RT-PCR, caspase-3 activity assay and checkerboard combination assay were performed to investigate the degree of resistance developed in sublines and to reverse drug resistance phenotype. Results: The flow cytometry histograms of drug accumulation assays demonstrated that the drug-resistant cell lines are P-gp and MRP1 positive. RT-PCR results showed that the resistant sublines express both MDR1 and MRP1 genes. Resistance indices of each subline to each anticancer drug were determined using the MTT cytotoxicity assay and it was found that all the sublines were resistant to their respective agents. Caspase-3 activities of the cell lines were also determined. Caspase-3 activity is an important indicator of apoptosis in the cell. The reversal of MDR was attempted by two cinnamylidene ketone and two organosilicon compounds. The results indicated that these compounds modulated P-gp effectively, but they were not very effective at reversing MRP1 activity in the MCF-7 sublines. Four selective anticancer drugs (paclitaxel, docetaxel, doxorubicin and vincristine) and four synthetic MDR modulators [2-(2-methoxycinnamylidene) indan-1-one (cinnamylidene-1), 2-(2- methoxycinnamylidene)3,4-dihydro-2H-naphthelen-1-one) (cinnamylidene-2), ALIS 409 and ALIS 421] were applied to the sublines in combination. The fractional inhibitory indices illustrated that combined applications of cinnamylidene ketones and organosilicon compounds with paclitaxel, docetaxel or vincristine exerted significant antiproliferative effects on the resistant sublines. Conclusion: This report demonstrates the development of rational models for drug resistance MCF-7 cell lines and reversal of acquired drug resistance.


Investigation of docetaxel and doxorubicin resistance in mcf-7 breast carcinoma cell line
Darcansoy İşeri, Özlem; Gündüz, Ufuk; Department of Biotechnology (2009)
Multidrug resistance phenotype of tumor cells describes resistance to wide range of structurally unrelated anticancer agents and is a serious limitation to effective chemotherapy. It is a multifactor yet not fully elucidated phenomenon by the involvement of diverse cellular pathways. Aim of this study was to investigate the resistance mechanisms developed against docetaxel and doxorubicin that are widely used in the treatment of breast cancer in model cell line MCF-7. Resistant sublines were developed by ap...
Development and investigation of etoposide resistance in MCF-7 Breast cancer cell line
Kaplan, Esra; Gündüz, Ufuk; Department of Biology (2010)
Failure of chemotherapy in cancer patients because of development of drug resistance is a major problem. Alterations of DNA repair mechanisms and drug targets are among the important resistance mechanisms which are developed against topoisomerase II inhibitors etoposide and doxorubicin. Modifications in the expression levels of mismatch repair (MMR) genes due to resistance to topoisomerase II inhibitors are involved in breast cancer. In this study, etoposide resistant sublines were developed from MCF7 breas...
Identification of polymorphisms on the MDR1 gene among Turkish population and their effects on multidrug resistance in acute leukemia patients
Kaya, P; Gündüz, Ufuk; Arpaci, F; Ural, AU; Guran, S (2005-09-01)
Multidrug-resistance (MDR) phenotype is a serious limitation to the effective chemotherapeutic treatment of many cancer types, including leukemia. One of the most important proteins, the over-expression of which is responsible for the multidrug-resistance phenotype in many cancer types, is P-glycoprotein. This protein is the product of the MDR1 gene. In previous studies, single-nucleotide polymorphisms (SNPs) C3435T, G2677T, and T-129C in the MDR1 gene were shown to be correlated with lower P-glycoprotein e...
Expression of Multidrug Resistance 1, Lung Resistance Protein and Breast Cancer Resistance Protein Genes in Chronic Leukemias
Iseri, Ozlem D.; Kars, Meltem D.; Mutlu, Pelin; Avcu, Ferit; Ural, Ali U.; Gündüz, Ufuk (2011-01-01)
One of the major problems in treatment of leukemias is multidrug resistance, which is already present at diagnosis or develops after chemotherapy. The gene expression levels of multidrug resistance resistance 1 (MDR1), breast cancer resistance protein (BCRP) and lung resistance-resistance protein (LRP) were evaluated in blood samples of 20 CLL and 24 CML patients using RT-PCR. MDR1, BCRP and LRP expression levels were detected in 65%, 20% and 45% of CLL patients, and in 54%, 37% and 25% of CML patients, res...
Mutlu, Pelin; Pourianazar, Negar Taghavi; Yucel, Meral; Gündüz, Ufuk (2018-01-01)
Activation of the Wnt signaling in some types of cancer and its relation with chemotherapy resistance is a very interesting issue that has been emphasized in recent years. Although, it is known that increase in the activity of beta-catenin is important in blast transformation and drug resistance, the underlying mechanisms are still unclear. In this study, changes in the expression levels of 186 genes that are thought to be important in drug resistance and Wnt signaling pathways were determined by using qPCR...
Citation Formats
M. D. Kars, O. D. Iseri, U. Gündüz, A. U. Ural, F. Arpaci, and J. Molnar, “Development of rational in vitro models for drug resistance in breast cancer and modulation of MDR by selected compounds,” ANTICANCER RESEARCH, pp. 4559–4568, 2006, Accessed: 00, 2020. [Online]. Available: