Araştırma Çıktıları
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Item In silico analyses and global transcriptional profiling reveal novel putative targets for Pea3 transcription factor related to its function in neurons(PUBLIC LIBRARY SCIENCE, 2017-01-01) Kandemir, Basak; Dag, Ugur; Gungor, Burcu Bakir; Durasi, Ilknur Melis; Erdogan, Burcu; Sahin, Eray; Sezerman, Ugur; Kurnaz, Isil AksanPea3 transcription factor belongs to the PEA3 subfamily within the ETS domain transcription factor superfamily, and has been largely studied in relation to its role in breast cancer metastasis. Nonetheless, Pea3 plays a role not only in breast tumor, but also in other tissues with branching morphogenesis, including kidneys, blood vasculature, bronchi and the developing nervous system. Identification of Pea3 target promoters in these systems are important for a thorough understanding of how Pea3 functions. Present study particularly focuses on the identification of novel neuronal targets of Pea3 in a combinatorial approach, through curation, computational analysis and microarray studies in a neuronal model system, SH-SY5Y neuroblastoma cells. We not only show that quite a number of genes in cancer, immune system and cell cycle pathways, among many others, are either up- or down-regulated by Pea3, but also identify novel targets including ephrins and ephrin receptors, semaphorins, cell adhesion molecules, as well as metalloproteases such as kallikreins, to be among potential target promoters in neuronal systems. Our overall results indicate that rather than early stages of neurite extension and axonal guidance, Pea3 is more involved in target identification and synaptic maturation.Item Molecular modelling of the FOXO4-TP53 interaction to design senolytic peptides for the elimination of senescent cancer cells(ELSEVIER, 2021-01-01) Le, Hillary H.; Cinaroglu, Suleyman S.; Manalo, Elise C.; Ors, Aysegul; Gomes, Michelle M.; Sahbaz, Burcin Duan; Bonic, Karla; Marmolejo, Carlos A. Origel; Quentel, Arnaud; Plaut, Justin S.; Kawashima, Taryn E.; Ozdemir, E. Sila; Malhotra V, Sanjay; Ahiska, Yavuz; Sezerman, Ugur; Akcapinar, Gunseli Bayram; Saldivar, Joshua C.; Timucin, Emel; Fischer, Jared M.Background: Senescent cells accumulate in tissues over time as part of the natural ageing process and the removal of senescent cells has shown promise for alleviating many different age-related diseases in mice. Cancer is an age-associated disease and there are numerous mechanisms driving cellular senescence in cancer that can be detrimental to recovery. Thus, it would be beneficial to develop a senolytic that acts not only on ageing cells but also senescent cancer cells to prevent cancer recurrence or progression. Methods: We used molecular modelling to develop a series of rationally designed peptides to mimic and target FOXO4 disrupting the FOXO4-TP53 interaction and releasing TP53 to induce apoptosis. We then tested these peptides as senolytic agents for the elimination of senescent cells both in cell culture and in vivo. Findings: Here we show that these peptides can act as senolytics for eliminating senescent human cancer cells both in cell culture and in orthotopic mouse models. We then further characterized one peptide, ES2, showing that it disrupts FOXO4-TP53 foci, activates TP53 mediated apoptosis and preferentially binds FOXO4 compared to TP53. Next, we show that intratumoural delivery of ES2 plus a BRAF inhibitor results in a significant increase in apoptosis and a survival advantage in mouse models of melanoma. Finally, we show that repeated systemic delivery of ES2 to older mice results in reduced senescent cell numbers in the liver with minimal toxicity. Interpretation: Taken together, our results reveal that peptides can be generated to specifically target and eliminate FOXO4+ senescent cancer cells, which has implications for eradicating residual disease and as a combination therapy for frontline treatment of cancer. Funding: This work was supported by the Cancer Early Detection Advanced Research Center at Oregon Health \& Science University. (C) 2021 The Authors. Published by Elsevier B.V.Item Comparison of endometrial prostanoid profiles in three infertile subgroups: the missing part of receptivity?(ELSEVIER SCIENCE INC, 2020-01-01) Keles, Irem Demiral; Ulgen, Ege; Erkan, Melike Belkiz; Celik, Saliha Esin; Aydin, Yasemin; Onem, Ayse Nur; Kandemir, Hulya; Arslanoglu, Tugce; Apak, Mustafa Resat; Sezerman, Ugur; Yeh, John; Buyru, Faruk; Bastu, ErcanObjective: To study the prostanoid profile of the endometria of patients with recurrent implantation failure (RIF), unexplained infertility (UIF), and recurrent miscarriages (RM), and to compare them with the endometria of healthy fertile controls. Design: Prospective cohort study. Setting: University hospital. Patient(s): Fifteen patients with RIF, 18 patients with UIF, 16 patients with RM, and 23 fertile controls were recruited. Intervention(s): Endometrial samples were taken during the window of implantation. After tissue homogenization and extraction, analysis with ultra-performance liquid chromatography diode array detector electrospray ionisation tandemmass spectrometrywas performed. Main Outcome Measures: Concentrations of prostaglandin (PG) D1, PGE1, PGF1 alpha, 6-ketoPGF1 alpha GD2, PGE2, PGF2 alpha, 15-deoxy-Delta 12,14-PGJ2, PGD3, PGE3, PGF3 alpha, thromboxane B2, 13,14-dihydro-PGE1, 13,14-dihydro-PGF1 alpha, 13,14-dihydro-PGF2 alpha, 13,14dihydro-15-keto-PGE1, 13,14-dihydro-15-keto-PGE2, and 13,14-dihydro-15-keto-PGF2 alpha were assessed. Result(s): Comparison of the endometria of patients with UIF and the controls showed no statistically significant differences. When the endometria of patients with RIF were compared with the controls, thromboxane B2 (TXB2) was found significantly higher (843.1 pg/mg vs. 133.5 pg/mg). When the endometria of patients with RM were compared with controls, 13,14-dihydro-15-keto PGF2 alpha and TXB2 were found significantly higher (3907.30 pg/mg vs. 17.80 pg/mg and 858.7 pg/mg vs. 133.5 pg/mg respectively). Conclusion(s): We identified increased endometrial presence of TXB2 in patients with RM and RIF, and 13,14-dihydro-15-keto PGF2 alpha in patients with RM. Although common ground is observed for RM and RIF, prostanoids, on the other hand, might make their own contribution to endometrial receptivity as important as genes and proteins. Attempts to normalize the prostaglandin profile of the endometrium via enzymatic activity can open new therapeutic options. (C) 2019 by American Society for Reproductive Medicine.Item Investigation of base excision repair gene variants in late-onset Alzheimer's disease(PUBLIC LIBRARY SCIENCE, 2019-01-01) Ertuzun, Tugce; Semerci, Asli; Cakir, Mehmet Emin; Ekmekcioglu, Aysegul; Gok, Mehmet Oguz; Soltys, Daniela T.; de Souza-Pinto, Nadja C.; Sezerman, Ugur; Muftuoglu, MeltemBase excision repair (BER) defects and concomitant oxidative DNA damage accumulation play a role in the etiology and progression of late-onset Alzheimer's disease (LOAD). However, it is not known whether genetic variant(s) of specific BER genes contribute to reduced BER activity in LOAD patients and whether they are associated with risk, development and/or progression of LOAD. Therefore, we performed targeted next generation sequencing for three BER genes, uracil glycosylase (UNG), endonuclease VIII-like DNA glycosylase 1 (NEIL1) and polymerase beta (POL beta) including promoter, exonic and intronic regions in peripheral blood samples and postmortem brain tissues (temporal cortex, TC and cerebellum, CE) from LOAD patients, high-pathology control and cognitively normal age-matched controls. In addition, the known LOAD risk factor, APOE was included in this study to test whether any BER gene variants associate with APOE variants, particularly APOE epsilon 4. We show that UNG carry five significant variants (rs1610925, rs2268406, rs80001089, rs1018782 and rs1018783) in blood samples of Turkish LOAD patients compared to age-matched controls and one of them (UNG rs80001089) is also significant in TC from Brazilian LOAD patients (p<0.05). The significant variants present only in CE and TC from LOAD are UNG rs2569987 and POL beta rs1012381950, respectively. There is also significant epistatic relationship (p = 0.0410) between UNG rs80001089 and NEIL1 rs7182283 in TC from LOAD subjects. Our results suggest that significant BER gene variants may be associated with the risk of LOAD in non-APOE epsilon 4 carriers. On the other hand, there are no significant UNG, NEIL1 and POL beta variants that could affect their protein level and function, suggesting that there may be other factors such as post-transcriptional or-translational modifications responsible for the reduced activities and protein levels of these genes in LOAD pathogenesis. Further studies with increased sample size are needed to confirm the relationship between BER variants and LOAD risk.Item Multiplex-PCR-Based Screening and Computational Modeling of Virulence Factors and T-Cell Mediated Immunity in Helicobacter pylori Infections for Accurate Clinical Diagnosis(PUBLIC LIBRARY SCIENCE, 2015-01-01) Oktem-Okullu, Sinem; Tiftikci, Arzu; Saruc, Murat; Cicek, Bahattin; Vardareli, Eser; Tozun, Nurdan; Kocagoz, Tanil; Sezerman, Ugur; Yavuz, Ahmet Sinan; Sayi-Yazgan, AycaThe outcome of H. pylori infection is closely related with bacteria's virulence factors and host immune response. The association between T cells and H. pylori infection has been identified, but the effects of the nine major H. pylori specific virulence factorsItem Progesterone at high doses reduces the growth of U87 and A172 glioblastoma cells: Proteomic changes regarding metabolism and immunity(WILEY, 2020-01-01) Altinoz, Meric A.; Ucal, Yasemin; Yilmaz, Muazzez C.; Kiris, Irem; Ozisik, Ozan; Sezerman, Ugur; Ozpinar, Aysel; Elmaci, IlhanWhile pregnancy may accelerate glioblastoma multiforme (GBM) growth, parity and progesterone (P4) containing treatments (ie, hormone replacement therapy) reduce the risk of GBM development. In parallel, low and high doses of P4 exert stimulating and inhibitory actions on GBM growth, respectively. The mechanisms behind the high-dose P4-suppression of GBM growth is unknown. In the present study, we assessed the changes in growth and proteomic profiles when high-dose P4 (100 and 300 mu M) was administered in human U87 and A172 GBM cell lines. The xCELLigence system was used to examine cell growth when different concentrations of P4 (20, 50, 100, and 300 mu M) was administered. The protein profiles were determined by two-dimensional gel electrophoresis in both cell lines when 100 and 300 mu M P4 were administered. Finally, the pathways enriched by the differentially expressed proteins were assessed using bioinformatic tools. Increasing doses of P4 blocked the growth of both GBM cells. We identified 26 and 51 differentially expressed proteins (fc > 2) in A172 and U87 cell lines treated with P4, respectively. Only the pro-tumorigenic mitochondrial ornithine aminotransferase and anti-apoptotic mitochondrial 60 kDa heat shock protein were downregulated in A172 cell line and U87 cell line when treated with P4, respectively. Detoxification of reactive oxygen species, cellular response to stress, glucose metabolism, and immunity-related proteins were altered in P4-treated GBM cell lines. The paradox on the effect of low and high doses of P4 on GBM growth is gaining attention. The mechanism related to the high dose of P4 on GBM growth can be explained by the alterations in detoxification mechanisms, stress, and immune response and glucose metabolism. P4 suppresses GBM growth and as it is nontoxic in comparison to classical chemotherapeutics, it can be used as a new strategy in GBM treatment in the future.Item The importance of dysregulated miRNAs on ovarian cysts and epithelial ovarian cancer(IMR PRESS, 2021-01-01) Gumusoglu, Ece; Gunel, Tuba; Hosseini, Mohammad Kazem; Seymen, Nogayhan; Senol, Taylan; Sezerman, Ugur; Topuz, Samet; Aydinli, KilicObjective: Benign ovarian cysts (BOC) are the most common tumors in women of reproductive age. Usually, these cysts are harmless, but, a small number of them occasionally progress to malignancy. Among ovarian malignancies, epithelial ovarian cancer (EOC) comprises 90\% and is the most important cause of gynecologic cancerrelated deaths. We aimed to identify dysregulated miRNAs in patients with benign ovarian cysts (n = 11) compared to EOC (n = 10) and to healthy individuals (HI) (n = 15). Methods: The serum samples from EOC and BOC patients were collected before operation. We studied three different sample groups (serum of EOC (n = 8), HI (n = 8), and BOC (n = 8) patients) that contained the highest-quality of RNA. Microarray data were analyzed according to expression of miRNAs and target genes by bioinformatics tools. Results: When compared to EOC samples, 75 miRNAs were dysregulated in BOC samples. Sixty-six miRNAs from BOC were dysregulated when compared to HI samples. Bioinformatics analysis of BOC vs. EOC and BOC vs. HI showed that 46 miRNAs were congruent and their expression alterations were similar (up- or down-regulated). Further analysis showed that these 46 miRNAs are associated to one of three pathways involved in cancer pathogenesis. Conclusion: Several miRNAs might playa role in BOC formation and/or malignant transformation. These dysregulated miRNAs could potentially be a biomarker to distinguish between a completely BOC and one that is malignant or has potential for malignant transformation.Item GUT MICROBIOTA EFFECTS IN HEMATOPOIETIC STEM CELL TRANSPLANT PATIENTS(ISTANBUL UNIV, FAC MEDICINE, PUBL OFF, 2022-01-01) Gurer, Ekin Ece; Oguz, Fatma S. A. V. R. A. N.; Kalayoglu, Sevgi BEsIsIK.; Aktas, Zerrin; Gulbas, Zafer; Oncul, Mustafa Oral; Sezerman, UgurObjective: In our study, we analyzed gut microbiota in allo-HSCT patients and aimed to evaluate the relationship of gut microbio-ta with transplant complications, mainly GVHD. Materials and Methods: A total of 25 adult recipients and do-nors who underwent allo-HSCT at Istanbul Anadolu Medical Center were included in the study. Stool samples were collected twice, before chemotherapy regimen and after allo-HSCT. Sam-ples were analyzed by High Melting (HRM) Analysis and Next Generation Sequencing (NGS) methods after nucleic acid iso-lation. Sequencing was done with Illumina MiSeq. Bacteria Silva database was used for taxonomic classification and QIIME 2 pro-grams were used for analysis. Statistical analyses were carried out with the R statistical programming language. Results: Twenty-five allo-HKHN recipients were included in the study. The mean age was 46.24 +/- 14.86 years in recipients and 43.40 +/- 13.20 years in donors. Gender distribution was M/F: 15/10 in patients and M/F: 17/8 in donors. Recipient and donor sib-ling HLA match was 10/10. The rate of GVHD associated with Allo-HSCT was 16\%, and the relapse rate was 16\%. It was ob-served that the Firmicutes and Proteobacteria phyla changed significantly before and after transplantation. The number of Entereccocus species was found to be higher in patients who developed GVHD and died. The loss of diversity was found to be statistically significant in the pre-transplant and post-engraft-ment samples of the patients. Conclusion: Gut microbiota diversity may guide the monitoring of GVHD and also may be manipulated for the treatment of GVHD. It is thought that increasing the diversity of commensal bacteria can also positively affect the prognosis of the disease.Item Understanding the impacts of self-shuffling approach on structure and function of shuffled endoglucanase enzyme via MD simulations(WALTER DE GRUYTER GMBH, 2020-01-01) Yenenler, Asli; Gerlevik, Umut; Sezerman, UgurObjective: We identify the impacts of structural differences on functionality of EG3\_S2 endoglucanase enzyme with MD studies. The results of previous experimental studies have been explained in details with computational approach. The objective of this study is to explain the functional differences between shuffled enzyme (EG3\_S2) and its native counterpart (EG3\_nat) from Trichoderma reseei, via Molecular Dynamics approach. Materials and methods: For this purpose, we performed MD simulations along 30 ns at three different reaction temperatures collected as NpT ensemble, and then monitored the backbone motion, flexibilities of residues, and intramolecular interactions of EG3\_S2 and EG3\_nat enzymes. Results: According to MD results, we conclude that EG3 S2 and EG3\_nat enzymes have unique RMSD patterns, e.g. RMSD pattern of EG3\_S2 is more dynamic than that of EG3\_nat at all temperatures. In addition to this dynamicity, EG3 S2 establishes more salt bridge interactions than EG3\_nat. Conclusion: By taking these results into an account with the preservation of catalytic Glu residues in a proper manner, we explain the structural basis of differences between shuffled and native enzyme via molecular dynamic studies.Item A possible founder mutation in FZD6 gene in a Turkish family with autosomal recessive nail dysplasia(BMC, 2019-01-01) Saygi, Ceren; Alanay, Yasemin; Sezerman, Ugur; Yenenler, Asli; Ozoren, NesrinBackgroundAutosomal recessive nail dysplasia is characterized by thick and hard nails with a very slow growth on the hands and feet. Mutations in FZD6 gene were found to be associated with autosomal recessive nail dysplasia in 2011. Presently, only seven mutations have been reported in FZD6 gene