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YALÇIN, AHMET SUHA

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YALÇIN

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AHMET SUHA

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Now showing 1 - 10 of 21
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    PublicationOpen Access
    Anti-cancer effects of curcumin, quercetin and tea catechins
    (MARMARA UNIV, FAC PHARMACY, 2016-09-20) YALÇIN, AHMET SUHA; Yalcin, A. Suha; Yilmaz, Ayse Mine; Altundag, Ergul Mutlu; Kocturk, Semra
    Polyphenols are present in high amounts in all parts of plants including roots, seeds, flowers, leaves, branches and trunk as well as plant derived products such as tea, coffee and wine. Extensive amount of information is available on biological effects of polyphenols including antioxidant, anti-cancer, anti-inflammatory, anti-coagulant and anti-microbial activities. In recent years, researchers have turned their interest towards identifying molecular mechanisms underlying the anti-cancer effects of these compounds. However, the limited bioavailability of polyphenols and the existence of differences in cancer cells in terms of intracellular mechanisms affected has necessitated the use of specific approaches to individual cancer cell types as well as methods of increasing bioavailability. In this review, the structures, bioavailability, biological activities and molecular mechanisms of anti-cancer effects of curcumin, quercetin and tea catechins are discussed.
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    Comparison of antioxidant capacity, protein profile and carbohydrate content of whey protein fractions
    (ELSEVIER SCI LTD, 2014) YALÇIN, AHMET SUHA; Onay-Ucar, Evren; Arda, Nazli; Pekmez, Murat; Yilmaz, Ayse Mine; Boke-Sarikahya, Nazli; Kirmizigul, Suheyla; Yalcin, A. Suha
    Whey is used as an additive in food industry and a dietary supplement in nutrition. Here we report a comparative analysis of antioxidant potential of whey and its fractions. Fractions were obtained by size exclusion chromatography, before and after enzymatic digestion with pepsin or trypsin. Superoxide radical scavenging, lipid peroxidation inhibition and cupric ion reducing activities of different fractions were checked. Peptides were detected by SDS-PAGE and GC-MS was used to determine carbohydrate content of the fractions. All samples showed antioxidant activity and the second fraction of the trypsin hydrolysate showed the highest superoxide radical scavenging activity. CUPRAC value of this fraction was two-times higher than that of whey filtrate. The first fraction of the pepsin hydrolysate was the most effective inhibitor of lipid peroxidation. Each sample exhibited a different polypeptide profile. Different percentages of carbohydrates were identified in whey filtrate and in all second fractions, where galactose was the major component. (C) 2013 Elsevier Ltd. All rights reserved.
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    PublicationOpen Access
    Imaging Reactive Oxygen Species-Induced Modifications in Living Systems
    (MARY ANN LIEBERT, INC, 2016-06) YALÇIN, AHMET SUHA; Maulucci, Giuseppe; Bacic, Goran; Bridal, Lori; Schmidt, Harald H. H. W.; Tavitian, Bertrand; Viel, Thomas; Utsumi, Hideo; Yalcin, A. Suha; De Spirito, Marco
    Significance: Reactive Oxygen Species (ROS) may regulate signaling, ion channels, transcription factors, and biosynthetic processes. ROS-related diseases can be due to either a shortage or an excess of ROS. Recent Advances: Since the biological activity of ROS depends on not only concentration but also spatiotemporal distribution, real-time imaging of ROS, possibly in vivo, has become a need for scientists, with potential for clinical translation. New imaging techniques as well as new contrast agents in clinically established modalities were developed in the previous decade. Critical Issues: An ideal imaging technique should determine ROS changes with high spatio-temporal resolution, detect physiologically relevant variations in ROS concentration, and provide specificity toward different redox couples. Furthermore, for in vivo applications, bioavailability of sensors, tissue penetration, and a high signal-to-noise ratio are additional requirements to be satisfied. Future Directions: None of the presented techniques fulfill all requirements for clinical translation. The obvious way forward is to incorporate anatomical and functional imaging into a common hybrid-imaging platform.
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    Effect of different culture media on isolation and differentiation of dendritic cells
    (WALTER DE GRUYTER GMBH, 2015) YALÇIN, AHMET SUHA; Yilmaz, Ayse Mine; Altundag, Ergul Mutlu; Gedik, Gulsah; Kocturk, Semra; Yalcin, A. Suha; Taga, Yavuz
    Objective: Dendritic cells (DCs) are members of the mammalian immune system and are considered to be the most powerful antigen presenting cells. They are responsible for the induction of T-cells or T-cell dependent immunity and tolerance. In this study we have investigated the effect of different serum supplements on generation and yield of mature dendritic cells isolated from peripheral blood mononuclear cells. Methods: Three different serum supplements (10% Fetal Bovine Serum, 1% Human Serum Albumin and 1% autologous serum) were compared with serum-free media to identify the role and importance of serum supplements on DC cultivation. Effect of different media on maturation signs (CD40, CD80, CD86, CD209a) and cytokine release (TNF-alpha, IL-10, IL-12, IL-6) was examined. Results: DCs generated in serum-free media was similar to those of cells in medium with autologous serum. Few dendritic-like cells were observed in fetal bovine serum and human serum albumin. The effect of different media on maturation of DCs was compared phenotypically and increased expression of CD80, CD86 and CD209a identified maturation and yield of DCs. Conclusion: Our results suggest that serum free media can be used to overcome potential drawbacks associated with different serum containing supplements.
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    Redox Regulation and Cancer Therapy
    (BENTHAM SCIENCE PUBL LTD, 2018) YALÇIN, AHMET SUHA; Yalcin, A. Suha; Karademir, Betul
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    Synergistic Induction of Apoptosis by Quercetin and Curcumin in Chronic Myeloid Leukemia (K562) Cells: II. Signal Transduction Pathways Involved
    (ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2021) YALÇIN, AHMET SUHA; Altundag, Ergul Mutlu; Yilmaz, Ayse Mine; Serdar, Belgin Sert; Jannuzzi, Ayse Tarbin; Kocturk, Semra; Yalcin, A. Suha
    Flavonoids are phenolic substances with chemo-preventive and chemotherapeutic properties. They are widely found in fruits and vegetables. The polyphenols quercetin and curcumin have antioxidant, anti-inflammatory, anti-carcinogenic, and pro-apoptotic properties. They were successfully used against different human cancers, especially chronic myeloid leukemia cancer cells. We have previously investigated anti-proliferative and apoptotic effects of quercetin and curcumin combination in K562 cells. Our data showed that they had beneficial synergistic effects. Based on these findings, we aimed to clarify signaling pathways involved in synergistic combination treatment with quercetin and curcumin in these cells. Proteins were investigated by Western blotting and by confocal microscopy. Changes in several genes in 10 different pathways related to cell proliferation, apoptosis, cell cycle, inflammation, hypoxia and oxidative stress were observed. Combination of quercetin and curcumin was effective on genes that were particularly related to p53, NF-kappa B and TGF-alpha pathways. Down-regulatory (CDKN1B, AKT1, IFN-gamma) and up-regulatory (BTG2, CDKN1A, FAS) effects on genes and related protein expressions may provide a multi-targeted therapy potential for chronic myeloid leukemia cancer cells without affecting healthy cells.
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    PublicationOpen Access
    Whey proteins: targets of oxidation, or mediators of redox protection
    (TAYLOR & FRANCIS LTD, 2019-08-12) YALÇIN, AHMET SUHA; Giblin, Linda; Yalcin, A. Suha; Bicim, Gokhan; Kramer, Anna C.; Chen, Zhifei; Callanan, Michael J.; Arranz, Elena; Davies, Michael J.
    Bovine whey proteins are highly valued dairy ingredients. This is primarily due to their amino acid content, digestibility, bioactivities and their processing characteristics. One of the reported bioactivities of whey proteins is antioxidant activity. Numerous dietary intervention trials with humans and animals indicate that consumption of whey products can modulate redox biomarkers to reduce oxidative stress. This bioactivity has in part been assigned to whey peptides using a range of biochemical or cellular assays in vitro. Superimposing whey peptide sequences from gastrointestinal samples, with whey peptides proven to be antioxidant in vitro, allows us to propose peptides from whey likely to exhibit antioxidant activity in the diet. However, whey proteins themselves are targets of oxidation during processing particularly when exposed to high thermal loads and/or extensive processing (e.g. infant formula manufacture). Oxidative damage of whey proteins can be selective with regard to the residues that are modified and are associated with the degree of protein unfolding, with alpha-Lactalbumin more susceptible than beta-Lactoglobulin. Such oxidative damage may have adverse effects on human health. This review summarises how whey proteins can modulate cellular redox pathways and conversely how whey proteins can be oxidised during processing. Given the extensive processing steps that whey proteins are often subjected to, we conclude that oxidation during processing is likely to compromise the positive health attributes associated with whey proteins.
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    The potential use of natural products to negate hepatic, renal and neuronal toxicity induced by cancer therapeutics
    (PERGAMON-ELSEVIER SCIENCE LTD, 2020) YALÇIN, AHMET SUHA; Prsa, Patrik; Karademir, Betul; Bicim, Gokhan; Mahmoud, Hatem; Dahan, Inbal; Yalcin, A. Suha; Mahajna, Jamal; Milisav, Irina
    Different types of chemotherapeutics are used for cancer treatment. These drugs act on several signal pathways, lead to programmed cell death, and damage cancer cells. Although many specific mechanisms of action have been suggested for chemotherapeutics, there are still gaps in understanding their effects. They may affect different components of the cell, particularly proteins with specific functions, such as enzymes. Recently, targeted and immuno therapies were introduced for treatment of different cancers. However, many cancer patients still depend on traditional and well-known drugs. Doxorubicin and platinum-based drugs are among the most frequently used chemotherapeutics. They are highly cytotoxic for cancer cells, but they also act on healthy cells. Hence, it is crucial to understand the mechanisms involved in order to decrease their side effects. Natural products, many of which are also available over-the-counter, may be considered to decrease various cancer drug-induced side effects. This review focuses on the use of these compounds to overcome side effects of chemotherapeutics, primarily doxorubicin and cisplatin, in the liver, kidney, and neuronal systems.
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    Whey Protein Versus Whey Protein Hydrolyzate for the Protection of Azoxymethane and Dextran Sodium Sulfate Induced Colonic Tumors in Rats
    (SPRINGER, 2012) YALÇIN, AHMET SUHA; Attaallah, Wafi; Yilmaz, Ayse Mine; Erdogan, Nusret; Yalcin, A. Suha; Aktan, A. Ozdemir
    Recent studies have shown that whey protein has many useful effects including its anti-cancer effect. In this study we have compared the protective effect of dietary whey protein with whey protein hydrolyzate against azoxymethane and dextran sodium sulfate induced colon cancer in rats. We used a rat model of the colon cancer induced by administration of azoxymethane followed by repeated dextran sodium sulfate ingestion which causes multiple tumor development. Colon tissues were analyzed histologically in addition to biochemical analyses performed by measuring lipid peroxidation, protein oxidation and glutathione levels in both of colon and liver tissues of rats after sacrification. Macroscopic and microscopic tumors were identified in all groups that received azoxymethane followed by repeated dextran sodium sulfate. Group fed with whey protein hydrolyzate showed significantly less macroscopic and microscopic tumor development compared with group fed with whey protein. The protocol applied to generate an appropriate model of colon cancer was successful. Whey protein hydrolyzate was found to be more effective in preventing colon tumor development compared with whey protein.
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    PublicationOpen Access
    European contribution to the study of ROS: A summary of the findings and prospects for the future from the COST action BM1203 (EU-ROS)
    (ELSEVIER, 2017-10) YALÇIN, AHMET SUHA; Egea, Javier; Fabregat, Isabel; Frapart, Yves M.; Ghezzi, Pietro; Gorlach, Agnes; Kietzmann, Thomas; Kubaichuk, Kateryna; Knaus, Ulla G.; Lopez, Manuela G.; Olaso-Gonzalez, Gloria; Petry, Andreas; Schulz, Rainer; Vinal, Jose; Winyard, Paul; Abbas, Kahina; Ademowo, Opeyemi S.; Afonso, Catarina B.; Andreadou, Ioanna; Antelmann, Haike; Antunes, Fernando; Aslan, Mutay; Bachschmid, Markus M.; Barbosa, Rui M.; Belousov, Vsevolod; Berndt, Carsten; Bernlohr, David; Bertran, Esther; Bindoli, Alberto; Bottari, Serge P.; Brito, Paula M.; Carrara, Guia; Casas, Ana I.; Chatzi, Afroditi; Chondrogianni, Niki; Conrad, Marcus; Cooke, Marcus S.; Costa, Joao G.; Cuadrado, Antonio; Dang, Pham My-Chan; De Smet, Barbara; Butuner, Bilge Debelec; Dias, Irundika H. K.; Dunn, Joe Dan; Edson, Amanda J.; El Assar, Mariam; El-Benna, Jamel; Ferdinandy, Peter; Fernandes, Ana S.; Fladmark, Kari E.; Forstermann, Ulrich; Giniatullin, Rashid; Giricz, Zoltan; Gorbe, Aniko; Griffiths, Helen; Hampl, Vaclav; Hanf, Alina; Herget, Jan; Hernansanz-Agustin, Pablo; Hillion, Melanie; Huang, Jingjing; Ilikay, Serap; Jansen-Durr, Pidder; Jaquet, Vincent; Joles, Jaap A.; Kalyanaraman, Balaraman; Kaminskyy, Danylo; Karbaschi, Mahsa; Kleanthous, Marina; Klotz, Lars-Oliver; Korac, Bato; Sami Korkmaz, Kemal; Koziel, Rafal; Kracun, Damir; Krause, Karl-Heinz; Kren, Vladimir; Krieg, Thomas; Laranjinha, Joao; Lazou, Antigone; Li, Huige; Martinez-Ruiz, Antonio; Matsui, Reiko; McBean, Gethin J.; Meredith, Stuart P.; Messens, Joris; Miguel, Veronica; Mikhed, Yuliya; Milisav, Irina; Milkovic, Lidija; Miranda-Vizuete, Antonio; Mojovic, Milos; Monsalve, Maria; Mouthuy, Pierre-Alexis; Mulvey, John; Munzel, Thomas; Muzykantov, Vladimir; Nguyen, Isabel T. N.; Oelze, Matthias; Oliveira, Nuno G.; Palmeira, Carlos M.; Papaevgeniou, Nikoletta; Pavicevic, Aleksandra; Pedre, Brandan; Peyrot, Fabienne; Phylactides, Marios; Pircalabioru, Gratiela G.; Pitt, Andrew R.; Poulsen, Henrik E.; Prieto, Ignacio; Pia Rigobello, Maria; Robledinos-Anton, Natalia; Rodriguez-Manas, Leocadio; Rolo, Anabela P.; Rousset, Francis; Ruskovska, Tatjana; Saraiva, Nuno; Sasson, Shlomo; Schroeder, Katrin; Semen, Khrystyna; Seredenina, Tamara; Shakirzyanova, Anastasia; Smith, Geoffrey L.; Soldati, Thierry; Sousa, Bebiana C.; Spickett, Corinne M.; Stancic, Ana; Stasia, Marie Jose; Steinbrenner, Holger; Stepanic, Visnja; Steven, Sebastian; Tokatlidis, Kostas; Tuncay, Erkan; Turan, Belma; Ursini, Fulvio; Vacek, Jan; Vajnerova, Olga; Valentova, Katerina; Van Breusegem, Frank; Varisli, Lokman; Veal, Elizabeth A.; Yalcin, A. Suha; Yelisyeyeva, Olha; Zarkovic, Neven; Zatloukalova, Martina; Zielonka, Jacek; Touyz, Rhian M.; Papapetropoulos, Andreas; Grune, Tilman; Lamas, Santiago; Schmidt, Harald H. H. W.; Di Lisa, Fabio; Daiber, Andreas
    The European Cooperation in Science and Technology (COST) provides an ideal framework to establish multi-disciplinary research networks. COST Action BM1203 (EU-ROS) represents a consortium of researchers from different disciplines who are dedicated to providing new insights and tools for better understanding redox biology and medicine and, in the long run, to finding new therapeutic strategies to target dysregulated redox processes in various diseases. This report highlights the major achievements of EU-ROS as well as research updates and new perspectives arising from its members. The EU-ROS consortium comprised more than 140 active members who worked together for four years on the topics briefly described below. The formation of reactive oxygen and nitrogen species (RONS) is an established hallmark of our aerobic environment and metabolism but RONS also act as messengers via redox regulation of essential cellular processes. The fact that many diseases have been found to be associated with oxidative stress established the theory of oxidative stress as a trigger of diseases that can be corrected by antioxidant therapy. However, while experimental studies support this thesis, clinical studies still generate controversial results, due to complex pathophysiology of oxidative stress in humans. For future improvement of antioxidant therapy and better understanding of redox-associated disease progression detailed knowledge on the sources and targets of RONS formation and discrimination of their detrimental or beneficial roles is required. In order to advance this important area of biology and medicine, highly synergistic approaches combining a variety of diverse and contrasting disciplines are needed.