Reversal of paclitaxel resistance in MCF-7 cell line by achemical modulator elacridar

Şener, Emine Çiğdem
The phenomenon called multi drug resistance (MDR) is the resistance of cancer cells to anticancer drugs before or during chemotherapy. One of the mechanisms causing MDR is the upregulation of efflux pumps. The overexpression of MDR1 and MRP1 results in increased efflux of anticancer agents. The aim of this study was to reverse MDR1-mediated paclitaxel resistance in MCF7 breast cancer cell line by a chemical MDR modulator elacridar. In this study, cytotoxicity and the reversal effect of elacridar on sensitive and paclitaxel resistant cells were investigated. The effect of elacridar on MDR1 and MRP1 gene expressions were also determined. Results indicated MDR1 gene was highly overexpressed (208 fold) in MCF7/Pac cells compared to MCF7/S cells. Elacridar was not found to be cytotoxic in MCF7/Pac cells up to 30µM. XTT results demonstrated 0.5µM elacridar concentration was able to restore the antiproliferative effect of paclitaxel by 94% in MCF7/Pac cells. Complete MDR reversal was achieved at 5µM elacridar concentration. qPCR results revealed dose dependent upregulations in MDR1 and MRP1 gene expression levels after elacridar treatment which did not prevent reversal of MDR by elacridar. Elacridar was shown to be very effective against paclitaxel resistance in MCF7/Pac cells at low concentrations. Therefore, it can be a suitable candidate for therapeutic applications in patients who developed paclitaxel resistance. Nevertheless, dose dependent upregulations in MDR1 and MRP1 gene expressions should be taken into consideration and overdose elacridar administration should be avoided.


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...
Reversal of breast cancer resistance protein mediated multidrug resistance in MCF7 breast adenocarcinoma cell line
Urfalı, Çağrı; Gündüz, Ufuk; Department of Biology (2011)
Resistance to various chemotherapeutic agents is a major problem in success of cancer chemotherapy. One of the primary reasons of development of multidrug resistance (MDR) is the overexpression of ATP binding cassette (ABC) transporter proteins. Breast cancer resistance protein (BCRP) belongs to ABC transporter family and encoded by ABCG2 gene. BCRP is mainly expressed in MDR1 (P-glycoprotein) lacking breast cancer cells. Overexpression of BCRP leads to efflux of chemotherapeutic agents at higher rates, the...
Reversal of multidrug resistance by synthetic and natural compounds in drug-resistant MCF-7 cell lines
Kars, Meltem Demirel; Iseri, Ozlem Darcansoy; Gündüz, Ufuk; Molnar, Jozsef (2008-01-01)
Background: Ineffectiveness of anticancer drugs is frequently observed in cancer chemotherapy. The resistance of tumor cells to various cytotoxic drugs is defined as multidrug resistance (MDR). The purpose of this study is to investigate the potential reversal effect of some synthetic and natural chemicals on drug-resistant MCF-7 cell lines. The effects of potential MDR modulators combined with some anticancer drugs were also studied. Methods: Flow cytometry, MTT cytotoxicity assays and checkerboard combina...
Expression analysis of TOP2A, MSH2 and MLH1 genes in MCF7 cells at different levels of etoposide resistance
Kaplan, Esra; Gündüz, Ufuk (2012-02-01)
Purpose: Development of resistance against anti-cancer drugs is one of the major obstacles of chemotherapy in the treatment of cancer. Etoposide is a topoisomerase II alpha (TOP2A) inhibitor, which is used in the treatment of breast cancer. Alterations in the expression of drug targets or DNA repair genes are among the important resistance mechanisms against TOP2A inhibitors. In this study, expression changes in TOP2A gene and two important mismatch repair (MMR) genes MSH2 and MLH1 were examined in order to...
Reversal of multidrug resistance by small interfering RNA (siRNA) in doxorubicin-resistant MCF-7 breast cancer cells
Donmez, Yaprak; Gündüz, Ufuk (2011-03-01)
Purpose: Resistance to anticancer drugs is a serious obstacle to cancer chemotherapy. A common form of multidrug resistance (MDR) is caused by the overexpression of transmembrane transporter proteins P-glycoprotein (P-gp) and multidrug resistance-associated protein-1 (MRP1), encoded by MDR1 and MRP1 genes, respectively. These proteins lead to reduced intracellular drug concentration and decreased cytotoxicity by means of their ability to pump the drugs out of the cells. Breast cancer tumor resistance is mai...
Citation Formats
E. Ç. Şener, “Reversal of paclitaxel resistance in MCF-7 cell line by achemical modulator elacridar,” M.S. - Master of Science, Middle East Technical University, 2012.