Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik
Permanent URI for this collectionhttps://hdl.handle.net/11147/9
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Conference Object Citation - WoS: 1A Study of Multiple Drug Resistance Mechanisms Improved Against Bortezomib on Multiple Myeloma Cell Lines in Vitro(American Society of Hematology, 2007) Uyuklu, Tolga; Ural, A. Uğur; Sarper, Metal; Avcu, Ferit; Baran, Yusuf; Elçi, Pınar; Akar, NejatThe most important problem in the treatment of Multiple Myeloma (MM) is the multi drug resistance (MDR) observed before and after the treatment. For this reason in MM cases an early resistance to treatment can be developed or the disease can relapsed in early period. Yet, there has been no improved drug resistance against proteazom inhibitor Bortezomib (Bor), which is used alone or with other chemotherapeutic agents in resistant or relapsed MM casesArticle Citation - WoS: 16Citation - Scopus: 16Multidrug Resistance Mediated by Mrp1 Gene Overexpression in Breast Cancer Patients(Taylor and Francis Ltd., 2009) Abaan, Ogan Demir; Mutlu, Pelin Kaya; Baran, Yusuf; Atalay, Can; Gündüz, UfukMultidrug resistance (MDR) is a serious handicap towards the effective treatment of breast cancer patients. One of the most prevalent MDR mechanisms is through the overexpression of genes coding the proteins called Multidrug Resistance-associated Proteins (MRPs). The aim of this study was to investigate the expression of MRP1 in tumor tissues from breast cancer patients. In this study, a semi-quantitative RT-PCR approach was utilized. Our results suggest that MRP1 overexpression can mediate MDR in patients. Pre-evaluation of the level of such MDR mediators before chemotherapy can increase the efficacy of the treatment.Article Citation - WoS: 38Citation - Scopus: 47Docetaxel/Zoledronic Acid Combination Triggers Apoptosis Synergistically Through Downregulating Antiapoptotic Bcl-2 Protein Level in Hormone-Refractory Prostate Cancer Cells(John Wiley and Sons Inc., 2009) Karabulut, B.; Erten, C.; Gül, M. K.; Cengiz, E.; Karaca, B.; Küçükzeybek, Y.; Görümlü, G.; Atmaca, H.; Uzunoğlu, S.; Şanlı, U. A.; Baran, Yusuf; Uslu, R.Docetaxel, a semi-synthetic taxane analogue, is used effectively in the treatment of metastatic prostate cancer. Zoledronic acid, the most potent member of bisphosphonates, has shown pleiotropic anti-tumoral effects on prostate cancer cells. We have explored the possible additive/synergistic effects and the apoptotic pathways induced by combination treatment of docetaxel and zoledronic acid in hormone and drug refractory, PC-3 and DU-145 prostate cancer cells. Combination of docetaxel and zoledronic acid synergistically inhibits cell growth in PC-3 and DU-145 cells. Moreover, this effect was due to downregulation of antiapoptotic protein Bcl-2 in PC-3 and DU-145 cells. In conclusion, docetaxel/zoledronic acid combination is potentially a novel and effective approach for the treatment of prostate cancer.Article Citation - WoS: 6Citation - Scopus: 6Docetaxel Enhances the Cytotoxic Effects of Imatinib on Philadelphia Positive Human Chronic Myeloid Leukemia Cells(Taylor and Francis Ltd., 2009) Güçlüler, Gözde; Baran, YusufChronic myelogenous leukemia (CML) results from a translocation between chromosomes 9 and 22 which generates BCR/ABL fusion protein and characterized by uncontrolled proliferation of immature white blood cells. Imatinib, a molecularly targeting anticancer agent, is used widely for the treatment of CML and showed significant activity in chronic and accelerated phases but much less in blast crisis phase. The resistance to imatinib especially in blast crisis phase is recognized as a major problem in the treatment of CML patients. Docetaxel is shown to arrest cells in G2/M phase of the cell cycle which makes cells more sensitive to chemo- and radiotherapy. In this study, we aimed to increase chemosensitivity of human K562 CML cells to imatinib in combination with docetaxel. Taken together, our results showed that the combination of imatinib and docetaxel decreased cellular proliferation and increased apoptosis in human K562 chronic myeloid leukemia cells as compared to any agent alone. Imatinib and docetaxel induced apoptosis through caspase-3 enzyme activity and mitochondrial membrane potential.Article Citation - WoS: 11Citation - Scopus: 16Bisphosphonate Treatment and Radiotherapy in Metastatic Breast Cancer(Humana Press, 2008) Ural, Ali Uğur; Avcu, Ferit; Baran, YusufPatients with advanced breast cancer frequently develop metastasis to bone. Bone metastasis results in intractable pain and high risk of pathologic fractures due to osteolysis. The treatment of breast cancer patients with bone metastases requires a multidisciplinary approach. Radiotherapy is an established treatment for metastatic bone pain. It may be delivered either as a localized low dose treatment for localized bone pain or systemically for more widespread symptoms. Bisphosphonates have been shown to reduce morbidity and bone pain from bone metastases when given to patients with metastatic bone disease. In vivo studies indicate that early bisphosphonates administration in combination with radiotherapy improves remineralization and restabilization of osteolytic bone metastases in animal tumor models. This review focused on a brief discussion about biology of bone metastases, the effects of radiotherapy and bisphosphonate therapy, and possible mechanisms of combination therapy in metastatic breast cancer patients.Article Citation - Scopus: 7Optimization of Transfection of Green Fluorescent Protein in Pursuing Mesenchymal Stem Cells in Vivo(Aves, 2008) Baran, Yusuf; Ural, Ali Uğur; Avcu, Ferit; Sarper, Meral; Elçi, Pınar; Pekel, AyselObjective: Green Fluorescent Protein (GFP) has been used as a marker of gene expression and a single cell marker in living organisms in cell biology studies. The important areas that GFP is used are expression levels of different genes in different organisms by inserting GFP in these genes and as a marker in living cells. In this study, we tried to optimize transfection of mesenchymal stem cells, (MSCs) used for regeneration of damaged tissues in animals, by GFP containing plasmid vector by which MSCs can be followed in vivo. Material and Methods: To this aim, phM-GFP plasmid vector carrying GFP gene and effectene transfection reagent were used. Result: The data revealed that twice transfection of MSCs resulted in higher expression of GFP for longer times as compared to once transfected MSCs. On the other hand, leaving the chemical transfection agents in the medium induced apoptosis after a while. Conclusion: As a conclusion we suggest the transfection of MSCs twice with 48 hours interval and removal of transfection agents after 8 hours which removed toxic and apoptotic effects of the chemicals.Letter Citation - WoS: 2Citation - Scopus: 3Rates of Myocardial Infarction and Coronary Artery Disease and Risk Factors in Patients Treated With Radiation Therapy for Early-Stage Breast Cancer(John Wiley and Sons Inc., 2007) Ural, Ali Uğur; Avcu, Ferit; Baran, YusufWe read the interesting article by Jagsi et al on the increased rates of coronary artery disease in patients treated with radiation therapy for early-stage breast cancer.1 In their study, those authors concluded that the findings support further assessment of clinical outcomes when newer techniques of chemotherapy planning are employed as well as investigation of the potential role of innovative techniques. However, there was no mention of the novel radiosensitizing and chemosensitizing effects of bisphosphonates (BPs), which inhibit tumor cell adhesion to bone, and tumor growth in breast cancer.Article Citation - WoS: 33Citation - Scopus: 35Upregulation 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, UfukThe 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.