Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik
Permanent URI for this collectionhttps://hdl.handle.net/11147/9
Browse
11 results
Search Results
Article Citation - WoS: 625Citation - Scopus: 698Flow Cytometry: Basic Principles and Applications(Taylor and Francis Ltd., 2017) Adan, Aysun; Alizada, Günel; Kiraz, Yağmur; Baran, Yusuf; Nalbant, AytenFlow cytometry is a sophisticated instrument measuring multiple physical characteristics of a single cell such as size and granularity simultaneously as the cell flows in suspension through a measuring device. Its working depends on the light scattering features of the cells under investigation, which may be derived from dyes or monoclonal antibodies targeting either extracellular molecules located on the surface or intracellular molecules inside the cell. This approach makes flow cytometry a powerful tool for detailed analysis of complex populations in a short period of time. This review covers the general principles and selected applications of flow cytometry such as immunophenotyping of peripheral blood cells, analysis of apoptosis and detection of cytokines. Additionally, this report provides a basic understanding of flow cytometry technology essential for all users as well as the methods used to analyze and interpret the data. Moreover, recent progresses in flow cytometry have been discussed in order to give an opinion about the future importance of this technology.Article Citation - WoS: 278Citation - Scopus: 295Molecular Mechanisms of Drug Resistance and Its Reversal in Cancer(Taylor and Francis Ltd., 2016) Kartal Yandım, Melis; Adan Gökbulut, Aysun; Baran, YusufChemotherapy is the main strategy for the treatment of cancer. However, the main problem limiting the success of chemotherapy is the development of multidrug resistance. The resistance can be intrinsic or acquired. The resistance phenotype is associated with the tumor cells that gain a cross-resistance to a large range of drugs that are structurally and functionally different. Multidrug resistance arises via many unrelated mechanisms, such as overexpression of energy-dependent efflux proteins, decrease in uptake of the agents, increase or alteration in drug targets, modification of cell cycle checkpoints, inactivation of the agents, compartmentalization of the agents, inhibition of apoptosis and aberrant bioactive sphingolipid metabolism. Exact elucidation of resistance mechanisms and molecular and biochemical approaches to overcome multidrug resistance have been a major goal in cancer research. This review comprises the mechanisms guiding multidrug resistance in cancer chemotherapy and also touches on approaches for reversing the resistance.Article Citation - WoS: 57Citation - Scopus: 67Resveratrol and Quercetin-Induced Apoptosis of Human 232b4 Chronic Lymphocytic Leukemia Cells by Activation of Caspase-3 and Cell Cycle Arrest(Taylor and Francis Ltd., 2013) Adan Gökbulut, Aysun; Apohan, Elif; Baran, YusufChronic lymphocytic leukemia (CLL), defined by accumulation of pathogenic B cells, has a very complex biology due to various factors such as inherited, host, and enviromental factors. Recently, finding new therapeutic agents or development of novel treatment strategies have been paid attention. Resveratrol and quercetin, important phytoalexins found in many plants, have been reported to have cytotoxic effects on various types of cancer. In this study, we examined cytotoxic, cytostatic, and apoptotic effects of these two important phenolic compounds on 232B4 human CLL cells. Cytotoxic effects of resveratrol and quercetin were determined by MTT cell proliferation assay. Changes in caspase-3 enzyme activity were measured using caspase-3 colorimetric assay. Annexin V-FITC/PI double staining was performed to measure apoptotic cell population. Effects of resveratrol and quercetin on cell cycle profiles of CLL cells were investigated by flow cytometry. Treatment of CLL cells with resveratrol and quercetin caused dose dependent inhibition of cell proliferation and increased apoptotic cell population through induction of caspase-3 activity. Cell cycle analysis displayed cell cycle arrest mainly in G0/G1 for both polyphenols. Our data, in total, showed for the first time that resveratrol and quercetin might block CLL growth through inducing apoptosis and cell cycle arrest.Article Citation - WoS: 9Citation - Scopus: 10The Roles of Epigenetic Modifications of Proapoptotic Bid and Bim Genes in Imatinibresistant Chronic Myeloid Leukemia Cells(Taylor and Francis Ltd., 2013) Bozkurt, Süreyya; Özkan, Tülin; Özmen, Füsun; Baran, Yusuf; Sunguroglu, Asuman; Kansu, EminIn chronic myeloid leukemia (CML), epigenetic modifications such as promoter hypermethylation and inactive histone modification are known mechanisms of drug resistance. In our study, we investigated the roles of promoter hypermethylation of BIM and BID genes and H3K27me3 histone modification on imatinib resistance. We detected higher expression levels of BIM and BID genes and lower expression levels of EZH2, EED2, SIRT1, and SUZ12 genes in imatinib-resistant K562/IMA-3 cells compared to imatinib-non-resistant K562 cells. While we determined the EZH2 and DNMT enzymes as bounded to the promoter of the BIM gene, we did not detect hypermethylation of this promoter. We also found the H3K27me3 histone modification promoter of BIM and BID genes in both cell lines. In conclusion, our results support the notion that DNA promoter methylation may be formed independently from EZH2-H3K27me3 and pro-apoptotic BIM and BID genes are not methyllated in the imatinib resistance of CML cells.Article Citation - WoS: 33Citation - Scopus: 35Imatinib Induces Autophagy Through Beclin-1 and Atg5 Genes in Chronic Myeloid Leukemia Cells(Taylor and Francis Ltd., 2011) Can, Geylani; Ekiz, Hüseyin Atakan; Baran, YusufLocate full-text(opens in a new window)|Full Text(opens in a new window)|View at Publisher| Export | Download | Add to List | More... Hematology Volume 16, Issue 2, March 2011, Pages 95-99 Imatinib induces autophagy through BECLIN-1 and ATG5 genes in chronic myeloid leukemia cells (Article) Can, G., Ekiz, H.A., Baran, Y. Department of Molecular Biology and Genetics, Faculty of Science, Izmir Institute of Technology, 35430 Urla, Izmir, Turkey View references (35) Abstract Imatinib is a chemotherapeutic drug used for the treatment of chronic myeloid leukemia (CML). Recent data showed imatinib-induced cell death in various types of cancers. Autophagy is the physiological process in which cellular components are broken down by the lysosomal activation. In this study, we aimed to examine the effects of imatinib on autophagy in addition to apoptosis in CML cells. Results suggested that imatinib induces autophagy in CML cells through inducing over-expression of BECLIN-1 and ATG5 genes with the statistical significance. Our results demonstrated that autophagy might be involved in imatinib-induced cell death.Article Citation - WoS: 31Citation - Scopus: 36Quercetin-Induced Apoptosis Involves Increased Htert Enzyme Activity of Leukemic Cells(Taylor and Francis Ltd., 2011) Avcı, Çığır Biray; Yılmaz, Sunde; Doğan, Zeynep Özlem; Saydam, Güray; Dodurga, Yavuz; Ekiz, Hüseyin Atakan; Kartal, Melis; Şahin, Fahri; Baran, Yusuf; Gündüz, CumhurWe aimed to examine the growth suppressive effects of quercetin on acute promyelocytic and lymphoblastic leukemia and chronic myeloid leukemia, and to find out whether the growth suppression is related to the blocking of telomerase enzyme activity. Cytotoxic effects of quercetin were shown by trypan blue analyses. Apoptotic effects of quercetin were examined by acridine orange and ethidium bromide staining by fluorescence microscopy. The effects of quercetin on telomerase enzyme activity were shown by hTERT Quantification Kit. Our results demonstrated that quercetin has antiproliferative and apoptotic effects on T-cell acute lymphoblastic leukemia (ALL), acute promyelocytic leukemia, and chronic myeloid leukemia (CML) cells. We also showed for the first time by this study that quercetin suppresses the activity of telomerase in ALL and CML cells. The results of this study show the importance of quercetin for its therapeutic potential in treatment of leukemias.Article 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: 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: 7Citation - Scopus: 7Nilotinib Significantly Induces Apoptosis in Imatinib Resistant K562 Cells With Wild-Type Bcr-Abl, as Effectively as in Parental Sensitive Counterparts(Taylor and Francis Ltd., 2010) Ekiz, Hüseyin Atakan; Can, Geylani; Gündüz, Ufuk; Baran, YusufChronic myeloid leukemia (CML) is a hematological malignancy characterized by high levels of immature white blood cells. CML is caused by the translocation between chromosomes 9 and 22 (which results in the formation of the Philadelphia chromosome) creating BCR-ABL fusion protein. Imatinib and nilotinib are chemotherapeutic drugs which specifically bind to the BCR-ABL and inhibit cancer cells. Nilotinib is more effective in this respect than imatinib. We have shown that nilotinib induces apoptosis in imatinib-resistant K562 CML cells which have the wild-type BCR-ABL fusion gene almost to the same extent as it does in the parental sensitive cells by the increase in caspase-3 enzyme activity and the decrease in mitochondrial membrane potential. This effect of nilotinib, even in low concentrations, may indicate the efficacy of the usage of nilotinib in imatinib-resistant CML with less risk of undesired cytotoxic effects in the remaining cells of the body. © 2010 W. S. Maney & Son Ltd.Article Citation - WoS: 12Citation - Scopus: 18Hematoprotective Effect of Seleno-L on Cyclophosphamide Toxicity in Rats(Taylor and Francis Ltd., 2009) Ayhancı, Adnan; Yaman, Suzan; Appak, Sıla; Güneş, SibelCyclophosphamide (CP) is a widely used antineoplastic drug that causes toxicity in the normal cell due to its metabolites. The major drawback of this drug is an undesirable myelosuppression. Selenium (Se) is a potent nutritional antioxidant that carries out biological effects by its incorporation into selenoproteins, such as glutathione peroxidase (GPx). The possible protective effects of seleno-l-methionine (SLM) against CP-related toxicity of blood cells and bone marrow of rats were investigated in this study. Intraperitoneal (i.p) administration of 50, 100, or 150mg/kg of CP caused, in a dose-dependent manner, reductions in the number of leukocytes (78, 89, and 92%, respectively), thrombocytes (22, 33, and 52%, respectively), and bone marrownucleated cells (72, 90, and 94%, respectively). The groups that had CP treatment alone were killed 3 days after the CP injection. For the groups having CPSLM, SLM (0.4 or 0.8mg/kg i.p) administration was started 3 days earlier than the CP administration and continued to the end of the experiment (6 days). On day 4, the animals were weighed again, relative doses of CP were estimated, and CPSLM was administered together. On day 7, blood samples were collected and bone marrow of animals were resected under anesthesia. The results indicated that treatment of rats within a select dose range of SLM could reduce CP-induced toxicity on blood cells and bone marrow.