Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik

Permanent URI for this collectionhttps://hdl.handle.net/11147/9

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  • Article
    Citation - WoS: 24
    Citation - Scopus: 24
    Mechanisms Responsible for Nilotinib Resistance in Human Chronic Myeloid Leukemia Cells and Reversal of Resistance
    (Informa Healthcare, 2013) Camgöz, Aylin; Gençer, Emel Başak; Ural, Ali Uğur; Baran, Yusuf
    Multidrug resistance remains a significant obstacle to successful chemotherapy. The ability to determine the possible resistance mechanisms and surmount the resistance is likely to improve chemotherapy. Nilotinib is a very effective drug in the treatment of imatinib-sensitive or -resistant patients. Although very successful hematologic and cytogenetic responses have been obtained in nilotinib-treated patients, in recent years cases showing resistance to nilotinib have been observed. We aimed to examine the mechanisms underlying nilotinib resistance and to provide new targets for the treatment of chronic myeloid leukemia (CML). There was an up-regulation of antiapoptotic BCR/ABL, GCS and SK-1 genes and MRP1 transporter gene and down-regulation of apoptotic Bax and CerS1 genes in nilotinib-resistant cells. There was no mutation in the nilotinib-binding region of BCR/ABL in resistant cells. Inhibiton of GCS and SK-1 restored nilotinib sensitivity. Targeting the proteins that are involved in nilotinib resistance in addition to the inhibition of BCR/ABL could be a better method of treatment in CML.
  • Article
    Citation - WoS: 33
    Citation - Scopus: 35
    Upregulation of Multi Drug Resistance Genes in Doxorubicin Resistant Human Acute Myelogeneous Leukemia Cells and Reversal of the Resistance
    (Taylor and Francis Ltd., 2007) Baran, Yusuf; Gür, Bala; Kaya, Pelin; Ural, Ali Uğur; Avcu, Ferit; Gündüz, Ufuk
    The major problem in the treatment of acute myeloid leukemia (AML) patients results from multidrug resistance to administered anticancer agents. Drug resistance proteins, MDR1 and MRP1, which work as drug efflux pumps, can mediate the multidrug resistance of human leukemia cells. In this study, the mechanisms of resistance to doxorubicin-induced cell death in human HL60 AML cells were examined. Continuous exposure of cells to step-wise increasing concentrations of doxorubicin resulted in the selection of HL60/DOX cells, which expressed about 10.7-fold resistance as compared to parental sensitive cells. The expression analyses of MRP1 and MDR1 drug efflux proteins in doxorubicin-sensitive and -resistant HL60 cells revealed that there was an upregulation of MRP1 gene in HL60/DOX cells as compared to parental sensitive cells. On the other hand, while there was no expression of MDR1 gene in parental cells, the expression of MDR1 gene was upregulated in HL60/DOX cells. HL60/DOX cells also showed cross-resistance to cytosine arabinoside (Ara-c). This resistance was reversed by a combination therapy of Ara-c and cyclosporine A. However, the expression levels of CD15 and CD16 surface markers were significantly decreased in HL60/DOX cells.