Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
Reversal of multidrug resistance by small interfering rnas (sirna) in doxorubicin resistant mcf-7 breast cancer cells
Download
index.pdf
Date
2010
Author
Dönmez, Yaprak
Metadata
Show full item record
Item Usage Stats
178
views
149
downloads
Cite This
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 and 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 mainly associated with overexpression of P-gp/MDR1. Although some chemical MDR modulators aim to overcome MDR by impairing the function of P-gp, they exhibit severe toxicities limiting their clinical relevance. Consequently, selective blocking of the expression of P-gp/MDR1 specific mRNA through RNA interference strategy may be an efficient tool to reverse MDR phenotype and increase the success of chemotherapy. Aim of this study was re-sensitizing doxorubicin resistant breast cancer cells to anticancer agent doxorubicin by selective downregulation of P-gp/MDR1 mRNA. The effect of the selected MDR1 siRNA and MRP1 expression after MDR1 silencing was determined by qPCR analysis. XTT cell proliferation assay was performed to v determine the effect of MDR1 silencing on doxorubicin sensitivity.Intracellular drug accumulation and localization was investigated by confocal laser scanning microscopy after treatment with MDR1 siRNA or other MDR modulators; verapamil or promethazine. The role of P-gp in migration characteristics of resistant cells was evaluated by wound healing assay. The results demonstrated that approximately 90% gene silencing occurred by the selected siRNA targeting MDR1 mRNA. However the level of MRP1 mRNA did not change after MDR1 downregulation. Introduction of siRNA resulted in about 70% re-sensitization to doxorubicin. Silencing of P-gp encoding MDR1 gene resulted in almost complete restoration of the intracellular doxorubicin accumulation and re-localization of the drug to the nuclei. Despite the considerably high concentration of the modulators, verapamil and promethazine were not as effective as siRNA for reversal of the drug efflux. According to wound healing assay, MDR1 silencing did not have any effect on migration characteristics of resistant cells, that is, P-gp expression does not seem to affect the motility of the cells. Selected siRNA duplex was shown to effectively inhibit MDR1 gene expression, restore doxorubicin accumulation and localization, and enhance chemo-sensitivity of resistant cells, which makes it a suitable future candidate for therapeutic applications.
Subject Keywords
Biology.
URI
http://etd.lib.metu.edu.tr/upload/3/12611496/index.pdf
https://hdl.handle.net/11511/19136
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
Preparation of polyethylene glycol coated magnetic nanoparticles for targeting of cancer cells
Keskin, Tuğba; Gündüz, Ufuk; Department of Biology (2012)
Conventional cancer chemotherapies cannot differentiate between healthy and cancer cells, and lead to severe side effects and systemic toxicity. In the last decades, different kinds of controlled drug delivery systems have been developed to overcome these shortcomings of chemotherapeutics. Magnetic nanoparticles (MNP) are potentially important in cancer treatment since they can be targeted to tumor site by an externally applied magnetic field. In this study, it is aimed to synthesize folic acid conjugated; ...
Partial purification and characterization of arylamine N-acetyltransferases from human breast tumor tissues
Su, Yaşasın Senem; Güray, Tülin; Department of Biochemistry (2006)
Arylamine N-acetyltransferases (NATs) were partially purified from human breast tumor tissues with complete separation of the isoforms in DEAE-Cellulose ion-exchange step. NAT with activity towards p-aminobenzoic acid (PABA) was isolated and purified from human breast tumor with 77 % yield and a purification factor of 5-fold. NAT with activity towards sulfamethazine (SMZ) was isolated and purified from human breast tumor with 21 % yield and a purification factor of 3-fold. Further purification attempts by B...
Metastatic behaviour of doxorubicin resistant MCF-7 breast cancer cells after Vimentin silencing
Tezcan, Okan; Gündüz, Ufuk; Department of Biology (2013)
Chemotherapy is one of the common treatments in cancer therapy. The effectiveness of chemotherapy is limited by several factors one of which is the emergence of multidrug resistance (MDR). MDR is caused by the activity of diverse ATP binding cassette (ABC) transporters that pump drugs out of the cells. There are several drugs which have been used in treatment of cancer. One of them is doxorubicin that intercalates and inhibits DNA replication. However, doxorubicin has been found to cause development of MDR ...
Mechanism of inhibition of cytochrome p4501a1 associated 7-ethoxyresorufin o-deethylase (erod) activity and glutathione s-transferase (gst) activities in fish liver by phenolic compounds/flavonoids
Yılmaz, Duygu; Arınç, Emel; Department of Biology (2010)
Flavonoids, present in fruits, vegetables and beverages derived from plants, have been described as health-promoting, disease-preventing dietary supplements, and have activity as cancer preventive agents. The cancer protective effects of flavonoids have been attributed to a wide variety of mechanisms, including modulating enzyme activities resulting in the decreased carcinogenicity of xenobiotics. Cytochrome P4501A1 (CYP1A1) is a Phase I enzyme which is known to be involved in the activation of procarcinoge...
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...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
Y. Dönmez, “Reversal of multidrug resistance by small interfering rnas (sirna) in doxorubicin resistant mcf-7 breast cancer cells,” M.S. - Master of Science, Middle East Technical University, 2010.
