Effect of doxorubicin on telomerase activity and apoptotic gene expression in doxorubicin-resistant and -sensitive MCF-7 cells

Eskiocak, Ugur
Iseri, Ozlem Darcansoy
Kars, Meltem Demirel
Bicer, Atilla
Gündüz, Ufuk
Background: Dose-and time-dependent effects of doxorubicin on telomerase activity ( TA) and expression levels of hTERT, Bcl-2, Bcl-x(L) and Bax were investigated in doxorubicin-resistant and -sensitive MCF-7 cells. Methods: Doxorubicin-resistant MCF-7/R was developed from sensitive MCF-7 breast carcinoma cell line and acquired resistance was demonstrated by XTT and mRNA analysis of MDR1 and MRP1 genes. Expression levels were determined by RT-PCR. Newly developed rapid and simple TRAP-silver staining assay was used to assess TA levels. Results: Doxorubicin-selected MCF-7 cells were 107-fold resistant to the drug and overexpress MDR1 and MRP1 genes. 72 h doxorubicin incubation caused a decrease in TA in parallel with a small decrease in hTERT level in both sensitive and resistant cells. Bcl-2 expression level decreased upon doxorubicin application in sensitive cells. However, the Bcl-x(L) level increased in sensitive cells after 72 h of doxorubicin incubation. Conclusion: This report demonstrates the inhibitory effects of doxorubicin on TA in both resistant and sensitive MCF-7 cells possibly through modulation of the apoptotic pathway genes. Copyright (C) 2008 S. Karger AG, Basel.


Effects of selenium supplementation on rat heart apex and right ventricle myocardia by using FTIR spectroscopy: A cluster analysis and neural network approach
TOYRAN AL OTAİBİ, NESLİHAN; Severcan, Feride; Severcan, Mete; TURAN, Belma (Elsevier BV, 2008-10-01)
The effects of selenium supplementation on apex and right ventricle myocardia of the rat heart were investigated using Fourier transform infrared (FTIR) spectroscopy by examining the changes in the frequency values of major absorptions arising from lipids and proteins. Cluster analysis was used to discriminate the selenium treated group from the control by utilizing two distinct spectral regions, belonging to absorptions arising from lipids and proteins, respectively. In addition, protein secondary structur...
Interactions of cholesterol reducing agent simvastatin with phospholipid model membranes
Koçak, Mustafa; Severcan, Feride; Department of Biochemistry (2007)
Interactions of simvastatin with zwitterionic dipalmitoyl phosphotidylcholine (DPPC) multilamellar liposomes were investigated as a function of temperature and simvastatin concentration. And acyl chain length effect on the simvastatin-model membrane interactions was monitored with DPPC and dimyristoyl phosphotidylcholine (DMPC) lipids. All studies were carried out by two non-invasive techniques, namely Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). The results s...
Effects of the non-steroidal anti-inflammatory drug celecoxib on cholesterol containing distearoyl phosphatidylcholine membranes
Sade, Asli; Banerjee, Sreeparna; Severcan, Feride (2011-01-01)
The effects of different concentrations of celecoxib on the acyl chain order, dynamics and the hydration status of the head group and interfacial region of model membranes containing DSPC and cholesterol were investigated in detail using Fourier transform infrared spectroscopy. Our results reveal that regardless of the presence of cholesterol, celecoxib is able to alter the physical properties of membranes. It exerts opposing effects on membrane order at high and low concentrations and decreases membrane fl...
Banerjee, Sreeparna(2013-12-31)
Effect of processing on buckwheat phenolics and antioxidant activity
Şensoy, İlkay; Ho, Chi-Tang; Karwe, Mukund V. (Elsevier BV, 2006-01-01)
The effect of processing on functional compounds in buckwheat was investigated. Extractions of buckwheat flour were carried out before and after roasting or extrusion. Folin-Ciocalteu assays indicated that processing did not cause any change in total phenolic content in buckwheat flour. Roasted (200 degrees C, 10 min) dark buckwheat flour exhibited an increase in non-polar compounds as well as polar compounds whereas extrusion exhibited increase only in polar compounds. Antioxidant activity test (DPPH) show...
Citation Formats
U. Eskiocak, O. D. Iseri, M. D. Kars, A. Bicer, and U. Gündüz, “Effect of doxorubicin on telomerase activity and apoptotic gene expression in doxorubicin-resistant and -sensitive MCF-7 cells,” CHEMOTHERAPY, pp. 209–216, 2008, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/31459.