WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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Now showing 1 - 10 of 67
  • Article
    Citation - WoS: 5
    Citation - Scopus: 7
    Five New Cardenolides Transformed From Oleandrin and Nerigoside by Alternaria Eureka 1e1bl1 and Phaeosphaeriasp. 1e4cs-1 and Their Cytotoxic Activities
    (Elsevier Ltd., 2021) Karakoyun, Çiğdem; Küçüksolak, Melis; Bilgi, Eyüp; Doğan, Gamze; Çömlekçi, Yiğit Ege; Bedir, Erdal
    Biotransformation of oleandrin (1) and nerigoside (2) by endophytic fungi; Alternaria eureka 1E1BL1 and Phaeospheria sp. 1E4CS-1, has led to the isolation of five new metabolites (3, 5, 6, 7 and 8) together with a known compound (4). The structures of the biotransformation products were elucidated by 1D-, 2D NMR and HR-MS. Phaeospheria sp. mainly provided monooxygenation reactions on the A and B rings, whereas A. eureka afforded both monooxygenated and desacetylated derivatives of the substrates. Cytotoxic activity of the compounds was tested against a non-cancerous (HEK-293) and four cancer (PANC-1, MIA PaCa-2, DU 145 and A549) cell lines by MTT cell viability assay. All compounds were less cytotoxic than oleandrin, which had IC50 values ranging between 2.7 and 41.9 nM. Two of the monohydroxylated metabolites, viz. 7(?)-hydroxy oleandrin (3) and 1(?)-hydroxy oleandrin (7), were also potent with IC50 values from 18.45 to 39.0 nM, while desacetylated + monohydroxylated, or dihydroxylated products had much lower cytotoxicity. Additionally, the lesser activity of 2 and its metabolite (6) possessing diginose as sugar residue inferred that oleandrose moiety is important for the toxicity of oleandrin as well as hydrophobicity of the steroid core. © 2020 Phytochemical Society of Europe
  • Conference Object
    Expression Levels of Ceramide-Metabolising Genes in Newly Diagnosed and Tyrosine Kinase Inhibitor-Resistant Chronic Myeloid Leukemia (cml) Patients: the Discovery of Novel Targets in Cml
    (Elsevier Ltd., 2014) Yandım, Melis Kartal; Kozanoğlu, İlknur; Özdoğu, Hakan; Pişkin, O.; Özcan, Mehmet Ali; Saydam, Göksel; Baran, Yusuf
    [No abstract available]
  • Conference Object
    Inhibition of Jumonji C Domain Containing Histone Demethylases in Acute Myeloid Leukemia
    (Elsevier Ltd., 2014) Hastar, N.; Koca, D.; Baran, Yusuf
    [No abstract available]
  • Conference Object
    Cytotoxic and Cytostatic Effects of Ponatinib on Imatinib-Sensitive And-Resistant Chronic Myeloid Leukemia Cells
    (Elsevier Ltd., 2014) Yandım, Melis Kartal; Baran, Yusuf
    [No abstract available]
  • Conference Object
    Targeting Sphingosine Kinase-1/Spingosine-1-phosphate Receptor 2 Signalling Pathway To Overcome T315i Mutation in 32dcl3 Cells
    (Elsevier Ltd., 2014) Adan Gökbulut, Aysun; Öğretmen, Besim; Baran, Yusuf
    The main problem in chronic myeloid leukemia patients is the development of resistance against tyrosine kinase inhibitors. The expression of BCR-ABL1 having T315 mutation is responsible for the development of nilotinib resistance. The alterations in sphingolipid signalling pathway is a significant BCR-ABL1-dependent resistance mechanism. Recently, we showed that sphingosine kinase-1 (SK-1)/sphingosine-1 phosphate (S1P)-mediated drug resistance is transduced via sphingosine-1 phosphate receptor 2 (S1P2) that inhibits protein phosphatase 2A (PP2A), causing increased stability of BCR-ABL1. However, specific signaling cascade involved in this process remain unkown. In this study, BCR-ABL1 expressing 32Dcl3 cells, 32D-p210Bcr-Abl(wt) and 32D-p210Bcr-Abl (T315I) were used. The antiproliferative effects of nilotinib, SK-1 inhibitor (PF-543), S1P2 inhibitor (JTE-013), phospholipase C inhibitor (U-73122) and nilotinib/PF-543 and nilotinib/JTE-013 combinations on wt and resistant cells were determined by MTT assay. Isobologram analysis was performed using CompuSyn program.
  • Conference Object
    Therapeutic Potential of Fisetin, Vitexin and Hesperetin on Chronic Myeloid Leukemia Cells
    (Elsevier Ltd., 2014) Adan Gökbulut, Aysun; Baran, Yusuf
    In Chronic Myeloid Leukemia (CML) treatment, despite therapeutic efficacy of tyrosine kinase inhibitors, resistance development and side effects cause problems. Fisetin, vitexin and hesperetin are plant-derived flavonoids. In this study, therapeutic potentials of fisetin, vitexin and hesperetin were determined in CML cells. Cytotoxic effects of flavonoids were determined by MTT assay while apoptotic effects were determined by changes in caspase- 3 activity, loss of mitochondrial membrane potential (MMP) and Annexin V/PI double staining. Cytostatic effects of the flavonoids were evaluated by propidium iodide staining using flow cytometry.
  • Conference Object
    A Novel Biomarker for Drug Resistance in Chronic Myeloid Leukemia: Microrna-17
    (Elsevier Ltd., 2014) Baran, Yusuf; Fıratlıgil, Burcu; Kartal Yandım, Melis; Kiraz, Yağmur; Kozanoğlu, İlknur; Özdoğu, Hakan; Ünal, Ali
    miRNAs are single stranded small RNA molecules (20–22 nt), which do not have ability to code for proteins. These types of RNAs play significant roles on gene regulation through inhibition of their target genes. In animals, most of miRNAs show their translational inhibitor effect on target mRNAs by semi-complementation to 3’UTR sequences of mRNAs and deadenylation that cause degradation of these mRNAs. The importance of miRNAs is increasing in cancer diagnosis and treatment since they are one of the major regulators of genes such as oncogenes, tumor suppressor genes. miR-17 is an oncogenic miRNA that suppress the activation of tumor suppressor genes like CDKN1A, p21 and E2F1. Based on previous information, we aimed to determine the correlation between expression levels of miR-17 microRNA in newly diagnosed, tyrosine kinase inhibitors treated and drug resistant CML patients.
  • Conference Object
    Cytotoxic and Apoptotic Effects of Fisetin, Hesperetin and Vitexinon Acute Promyelocytic Leukemia Cells
    (Elsevier Ltd., 2014) Adan Gökbulut, Aysun; Baran, Yusuf
    Acute Promyelocytic Leukaemia (APL) is characterized by abnormal accumulation of immature granulocytes in the bone marrow and the blood stream. To date, there is no definitive treatment strategy. Fisetin, hesperetin and vitexin are flavanoids found in fruits and vegetables. Their anticancer properties have been studied on several cancer types. In this study, we aimed to examine the cytotoxic, cytostatic and apoptotic effects of fisetin, hesperetin and vitexin on Acute Promyelocytic Leukaemia cells. Cytotoxic effects were evaluated by MTT assay while apoptotic effects of these flavonoids were examined by changes in caspase-3 activity, loss of mitochondrial membrane potential (MMP) and Annexin V/PI double staining. Cytostatic effects of the flavonoids were evaluated by propidium iodide staining using flow cytometry.
  • Conference Object
    Citation - WoS: 16
    Thermal Characterization of Ag and Ag Plus N Ion Implanted Ultra-High Molecular Weight Polyethylene (uhmwpe)
    (Elsevier Ltd., 2007) Urkaç, Emel Sokullu; Oztarhan, A.; Tıhmınlıoğlu, Funda; Kaya, N.; Ila, D.; Muntele, C.; Tek, Z.
    Most of total hip joints are composed of ultra-high molecular weight polyethylene (UHMWPE). However, as ultra-high molecular weight polyethylene is too stable in a body, wear debris may accumulate and cause biological response such as bone absorption and loosening of prosthesis. In this study, ultra-high molecular weight polyethylene samples were Ag and Ag + N hybrid ion implanted by using MEVVA ion implantation technique to improve its surface properties. Samples were implanted with a fluence of 10(17) ion/cm(2) and extraction voltage of 30 kV. Implanted and unimplanted samples were investigated by thermo-gravimetry analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), optical microscopy (OM) and contact Angle measurement. Thermal characterization results showed that the ion bombardment induced an increase in the % crystallinity, onset and termination degradation temperatures of UHMWPE. (c) 2007 Elsevier B.V. All rights reserved.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 9
    Polymeric Thermal Analysis of C+h and C+h+ar Ion Implanted Uhmwpe Samples
    (Elsevier Ltd., 2007) Kaya, N.; Öztarhan, Ahmet M.; Urkaç, Emel Sokullu; Ila, D.; Budak, S.; Oks, E.; Tıhmınlıoğlu, Funda; Muntele, C.
    Chemical surface characterization of C + H hybrid ion implanted UHMWPE samples were carried out using DSC (differential scanning calorimeter) and TGA (thermal gravimetric analysis) techniques. Samples were implanted with a fluence of 10(17) ion/cm(2) and an extraction voltage of 30 kV. The study of TGA and DSC curves showed that: (1) Polymeric decomposition temperature increased, (2) T-m, Delta C-p and Delta H-m values changed while Delta C-p and Delta H-m increased. T-g value could not be measured, because of some experimental limitations. However, the increase in Delta H-m values showed that T-g values increased, (3) the branch density which indicated the increase in number of cross-link (M-c) decreased in ion implanted samples and (4) increase in Delta H-m values indicated increase in crystallinity of implanted surface of UHMWPE samples.