Profil Resmi
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Araştırma Projeleri
Organizasyon Birimleri
İş Adı
Dr. Öğr. Üyesi

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Şimdi gösteriliyor 1 - 8 / 8
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    Co-Chaperone Bag-1 Plays a Role in the Autophagy-Dependent Cell Survival Through Beclin 1 Interaction
    (MDPI, 2021) Türk, Miray; Tatlı, Özge; Alkan, Hamza Furkan; KILBAŞ, PELİN ÖZFİLİZ; Alkurt, Gizem; Dinler Doğanay, Gizem
    Expression levels of the major mammalian autophagy regulator Beclin 1 and its interaction with Bcl-2 regulate the switch between autophagic cell survival and apoptotic cell death pathways. However, some of the regulators and the precise mechanisms of these processes still remain elusive. Bag-1 (Bcl-2 associated athanogene-1), a member of BAG family proteins, is a multifunctional pro-survival molecule that possesses critical functions in vital cellular pathways. Herein, we report the role of Bag-1 on Bcl-2/Beclin 1 crosstalk through indirectly interacting with Beclin 1. Pull-down experiments suggested a molecular interaction between Bag-1 and Beclin 1 in breast cancer cell lines. On the other hand, in vitro binding assays showed that Bag-1/Beclin 1 interaction does not occur directly but occurs through a mediator molecule. Bag-1 interaction with p-Beclin 1 (T119), indicator of early autophagy, is increased during nutrient starvation suggesting involvement of Bag-1 in the autophagic regulation. Furthermore, CRISPR/Cas9-mediated Bag-1 knock-out in MCF-7 cells hampered cell survival and proliferation and resulted in decreased levels of total LC3 under starvation. Collectively, we suggest that Bag-1 modulates cell survival/death decision through maintaining macroautophagy as a component of Beclin 1-associated complexes.
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    Interactome Analysis of Bag-1 Isoforms Reveals Novel Interaction Partners in Endoplasmic Reticulum-Associated Degradation
    (Public Library Science, 2021) Can, Nisan Denizce; Baştürk, Ezgi; Kızılboğa, Tuğba; Akçay, İzzet Mehmet; Dingiloğlu, Baran; Tatlı, Özge; Acar, Sevilay; KILBAŞ, PELİN ÖZFİLİZ; Elbeyli, Efe; Muratcioglu, Serena; Jannuzzi, Ayşe Tarbin; Gürsoy, Attila; Doğanay, Hamdi Levent; Yılmaz, Betül Karademir; Doğanay, Gizem Dinler
    Bag-1 is a multifunctional protein that regulates Hsp70 chaperone activity, apoptosis, and proliferation. The three major Bag-1 isoforms have different subcellular localizations and partly non-overlapping functions. To identify the detailed interaction network of each isoform, we utilized mass spectrometry-based proteomics and found that interactomes of Bag-1 isoforms contained many common proteins, with variations in their abundances. Bag-1 interactomes were enriched with proteins involved in protein processing and degradation pathways. Novel interaction partners included VCP/p97; a transitional ER ATPase, Rad23B; a shuttling factor for ubiquitinated proteins, proteasome components, and ER-resident proteins, suggesting a role for Bag-1 also in ER-associated protein degradation (ERAD). Bag-1 pull-down from cells and tissues from breast cancer patients validated these interactions and showed cancer-related prominence. Using in silico predictions we detected hotspot residues of Bag-1. Mutations of these residues caused loss of binding to protein quality control elements and impaired proteasomal activity in MCF-7 cells. Following CD147 glycosylation pattern, we showed that Bag-1 downregulated VCP/p97-dependent ERAD. Overall, our data extends the interaction map of Bag-1, and broadens its role in protein homeostasis. Targeting the interaction surfaces revealed in this study might be an effective strategy in the treatment of cancer.
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    In Vitro Investigations of miR-33a Expression in Estrogen Receptor-Targeting Therapies in Breast Cancer Cells
    (MDPI, 2021) KILBAŞ, PELİN ÖZFİLİZ; SÖNMEZ, ÖZLEM; Obakan-Yerlikaya, Pınar; Çoker-Gürkan, Ajda; Palavan-Ünsal, Narcin; Uysal-Onganer, Pınar; Arışan, Elif Damla
    Simple Summary: Altered metabolic pathways determine the aggressivity of breast cancer cells. To highlight the potential markers gains importance to understand early molecular signatures of disease. microRNAs are the small non-coding RNAs found in different biological samples. Due to the dysregulation of metabolic pathways, the expression and secretion of microRNAs are modulated. (1) Background: Increased fatty acid synthesis leads to the aggressive phenotype of breast cancer and renders efficiency of therapeutics. Regulatory microRNAs (miRNAs) on lipid biosynthesis pathways as miR-33a have potential to clarify the exact mechanism. (2) Methods: We determined miR-33a expression levels following exposure of MCF-7 and MDA-MB-231 breast cancer cells to estrogen receptor (ER) activator (estradiol-17 beta, E2) or anti-estrogens (ICI 182,780, Fulvestrant, FUL) at non-cytotoxic concentrations. We related miR-33a expression levels in the cells to cellular lipid biosynthesis-related pathways through immunoblotting. (3) Results: miR-33a mimic treatment led to significantly downregulation of fatty acid synthase (FASN) in MCF-7 cells but not in MDA-MB-231 cells in the presence of estradiol-17 beta (E2) or Fulvestrant (FUL). In contrast to the miR-33a inhibitor effect, miR-33a mimic co-transfection with E2 or FUL led to diminished AMP-activated protein kinase a (AMPKa) activity in MCF-7 cells. E2 increases FASN levels in MDA-MB-231 cells regardless of miR-33a cellular levels. miR-33a inhibitor co-treatment suppressed E2-mediated AMPKa activity in MDA-MB-231 cells. (4) Conclusions: The cellular expression levels of miR-33a are critical to understanding differential responses which include cellular energy sensors such as AMPKa activation status in breast cancer cells.
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    Examination of Fatty Acid Metabolism and Induction of Epithelial-Mesenchymal Transition Pathway via Modulation of miR-33a Levels in Caki-1 and Caki-2 Renal Cell
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    Investigation of the Effect of STAT3 Inhibition on Apoptotic Process Associated with JAK/STAT Signaling Pathway in A-498 and ACHN Renal Carcinoma Cells
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    The Comparison of Differentially Expressed microRNAs in Bag-1 Deficient and Wild Type MCF-7 Breast Cancer Cells by Small RNA Sequencing
    (TUBITAK Scientific & Technical Research Council Turkey, 2022) KILBAŞ, PELİN ÖZFİLİZ; Alkurt, Gizem; Obakan Yerlikaya, Pınar; Çoker Gürkan, Ajda; DİNLER DOĞANAY, GİZEM; Arısan, Elif Damla
    The multifunctional BAG-1 (Bcl-2 athanogene-1) protein promotes breast cancer survival through direct or indirect interaction partners. The number of the interacting partners determines its cellular role in different conditions. As well as interaction partner variability, the amount of BAG-1 protein in the cells could cause dramatic alterations. According to previous studies, while the transient silencing of Bag-1 enhanced drug-induced apoptosis, deletion of BAG-1 could induce stemness properties and Akt-mediated actin remodeling in MCF-7 breast cancer cells. Considering the heterogeneity of breast cancer and the variability of BAG-1-mediated cell response, it has become essential to determine microRNA (miRNA) functions in breast cancer depending on Bag-1 expression level. This study aims to compare microRNA expression levels in wt and Bag-1 knockout (KO) MCF-7 breast cancer cells. hsa-miR-429 was selected as a potential miRNA in BAG-1KO MCF-7 cells because of the downregulation both in bioinformatics and validation qRT-PCR assay. According to predicted mRNA targets and functional enrichment analysis the ten hub proteins that are phosphatidylinositol4,5-biphosphate 3-kinase catalytic subunit alpha (PIK3CA), kinase insert domain receptor (KDR), GRB2 associated binding protein 1 (GAB1), Rac family small GTPase1 (RAC1), vascular endothelial growth factor A (VEGFA), Cbl proto-oncogene (CBL), syndecan 2 (SDC2), phospholipase C gamma 1 (PLCG1), E1A binding protein p300 (EP300), and CRK like proto-oncogene, adaptor protein (CRKL) were identified as targets of hsa-miR-429. The functional enrichment analysis showed that the most significant proteins were enriched in PI3K/Akt, focal adhesion, cytoskeleton regulation, proteoglycans in cancer, and Ras signaling pathways. It was determined that hsa-miR-429 targeted these pathways in Bag-1 deficient conditions and could be used as a potential therapeutic target in future studies.
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    Specific c-Jun N-Terminal Kinase Inhibitor, JNK-IN-8 Suppresses Mesenchymal Profile of PTX-Resistant MCF-7 Cells through Modulating PI3K/Akt, MAPK and Wnt Signaling Pathways
    (MDPI, 2020) KILBAŞ, PELİN ÖZFİLİZ; Sönmez, Özlem; Uysal-Onganer, Pınar; Çoker Gürkan, Ajda; YERLİKAYA, PINAR OBAKAN; Arışan, Elif Damla
    Paclitaxel (PTX) is a widely used chemotherapeutic agent in the treatment of breast cancer, and resistance to PTX is a common failure of breast cancer therapy. Therefore, understanding the effective molecular targets in PTX-resistance gains importance in identifying novel strategies in successful breast cancer therapy approaches. The aim of the study was to investigate the functional role of PTX resistance on MCF-7 cell survival and proliferation related to PI3K/Akt and MAPK pathways. The generated PTX-resistant (PTX-res) MCF-7 cells showed enhanced cell survival, proliferation, and colony formation potential with decreased cell death compared to wt MCF-7 cells. PTX-res MCF-7 cells exhibited increased motility profile with EMT, PI3K/Akt, and MAPK pathway induction. According to the significant SAPK/JNK activation in PTX-res MCF-7 cells, specific c-Jun N-terminal kinase inhibitor, JNK-IN-8 is shown to suppress the migration potential of cells. Treatment of JNK inhibitor suppressed the p38 and SAPK/JNK and Vimentin expression. However, the JNK inhibitor further downregulated Wnt signaling members in PTX-res MCF-7 cells. Therefore, the JNK inhibitor JNK-IN-8 might be used as a potential therapy model to reverse PTX-resistance related to Wnt signaling.
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    Circulating MicroRNA Expression Profiles to Identify a Potential Link Between Prostate Cancer and Obesity
    (Elsevier, 2022) Arışan, Serdar; KILBAŞ, PELİN ÖZFİLİZ; RENCÜZOĞULLARI, ÖZGE; Ünsal, Narcin Palavan; Çoker-Gürkan, Ajda; Obakan-Yerlikaya, Pınar; Uysal-Onganer, Pınar; Arışan, Elif Damla
    Effective diagnostic methods are needed to apply appropriate treatment strategies in patients with aggressive prostate cancer. From this point of view, risk factors that cause prostate cancer or its aggressiveness should be considered. Obesity is a critical risk factor for triggering prostate cancer's metastatic properties. microRNAs are used as biomarkers in diagnosing cancer and obesity depending on their tissue-specific expression patterns. This study investigates the role of obesity in the metastatic profile of prostate cancer depending on the differential expression signatures of selected miRNAs in prostate cancer and obese patients. The roles of miR-100, miR-141 and miR-145 in prostate cancer and obesity are partially known. However, their potential to become circular biomarkers in the blood is not elucidated. There is no previous data on miR-4463 and miR-653 on prostate cancer and obesity association. In this study, the blood samples were taken and obtained serum from 69 patients of 6 subgroups that consisted of one healthy group and five unhealthy groups based on their different prostate cancer or obesity levels. Five selected miRNA expression analyses (miR-100, miR-141, miR-145, miR-4463, and miR-653) were performed through total RNA isolation, which was confirmed via synthetic cel-miR-39 miRNA. Quantitative Real-Time PCR analyzed the expression levels of selected miRNAs. Data analysis was performed via normalising target miRNA expression levels with cel-miR-39. In this study, we found that the relationship between prostate cancer and obesity was investigated at the molecular level. It was suggested that target miR-100 could be a promising biomarker for non-obese and aggressive prostate cancer patients. miR-145 is a more potential biomarker than miR-141 for non-aggressive and non-obese patients. miR-4463 can be used to predict more prostate cancer patients than obese patients. Lastly, miR-653 can be a biomarker for non-aggressive prostate cancer cells.