Targeting glucosylceramide synthase sensitizes imatinib-resistant chronic myeloid leukemia cells via endogenous ceramide accumulation

Bielawski, Jacek
Gündüz, Ufuk
Ogretmen, Besim
Purpose Drug resistance presents a major obstacle for the treatment of some patients with chronic myeloid leukemia (CML). Pro-apoptotic ceramide mediates imatinib-induced apoptosis, and metabolism of ceramide by glucosylceramide synthase (GCS) activity, converting ceramide to glucosyl ceramide, might contribute to imatinib resistance. In this study, we investigated the role of ceramide metabolism by GCS in the regulation of imatinib-induced apoptosis in drug-sensitive and drug-resistant K562 and K562/IMA-0.2 and K562/IMA-1 human CML cells, which exhibit about 2.3- and 19-fold imatinib resistance, respectively.


Effect of cobalt-60 (gamma radiation) on multidrug-resistant multiple myeloma cell lines
Mutlu, Pelin; Ural, A. Ugur; Avcu, Ferit; Dirican, Bahar; Beyzadeoglu, Murat; Gündüz, Ufuk (2011-07-01)
Emergence of resistance to chemotherapy and radiotherapy is a major obstacle for the successful treatment of MM (multiple myeloma). Prednisone, vincristine and melphalan are commonly used chemotherapeutic agents for the treatment of MM. In the current study, we examined the presence of possible cross-resistance between these drugs and gamma (gamma) radiation. Prednisone, vincristine and melphalan resistant RPMI-8226 and U-266 MM cells were generated by stepwise increasing concentrations of the drugs. The se...
Apoptotic Effects of Resveratrol, a Grape Polyphenol, on Imatinib-Sensitive and Resistant K562 Chronic Myeloid Leukemia Cells
Can, Geylani; Cakir, Zeynep; Kartal, Melts; Gündüz, Ufuk; BARAN, YUSUF (2012-07-01)
Aim: To examine the antiproliferative and apoptotic effects of resveratrol on imatinib-sensitive and imatinib-resistant K562 chronic myeloid leukemia cells. Materials and Methods: Antiproliferative effects of resveratrol were determined by the 3-Bis[2-methoxy-4-nitro-5-sulphophenyl]-2H-tetrazolium-5-carboxanilide inner salt (XTT) cell proliferation assay. Apoptotic effects of resveratrol on sensitive K562 and resistant K562/IMA-3 cells were determined through changes in caspase-3 activity, loss of mitochond...
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 in mcf-7 breast adenocarcinoma cell line by silencing interleukin 6 with RNA interference
Çakmak, Neşe; Gündüz, Ufuk; Department of Biology (2013)
Multidrug resistance (MDR) in cancer is characterized by development of resistance to several unrelated drugs upon long time administration of a certain type of chemotherapeutic agent. In doxorubicin resistant MCF-7 cell line, resistance is developed mainly by upregulation of MDR1 gene which encodes an ABC transporter protein known as P-glycoprotein. Interleukin 6 (IL-6) is a cytokine which acts as a growth factor for certain cell types including some cancer cells. IL-6 is found at high levels in cancer pat...
Synthesis of poly (dl-lactic-co-glycolic acid) coated magnetic nanoparticles for anti-cancer drug delivery
Tansık, Gülistan; Gündüz, Ufuk; Department of Biology (2012)
One of the main problems of current cancer chemotherapy is the lack of selectivity of anti-cancer drugs to tumor cells which leads to systemic toxicity and adverse side effects. In order to overcome these limitations, researches on controlled drug delivery systems have gained much attention. Nanoscale based drug delivery systems provide tumor targeting. Among many types of nanocarriers, superparamagnetic nanoparticles with their biocompatible polymer coatings can be targeted to an intented site by an extern...
Citation Formats
Y. BARAN, J. Bielawski, U. Gündüz, and B. Ogretmen, “Targeting glucosylceramide synthase sensitizes imatinib-resistant chronic myeloid leukemia cells via endogenous ceramide accumulation,” JOURNAL OF CANCER RESEARCH AND CLINICAL ONCOLOGY, pp. 1535–1544, 2011, Accessed: 00, 2020. [Online]. Available: