20 results on '"Arzu, Yalcin"'
Search Results
2. Protective effect of melatonin on learning and memory impairment and hippocampal dysfunction in rats induced by high-fructose corn syrup
- Author
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Arzu Yalcin, Mustafa Saygin, Ozlem Ozmen, Oguzhan Kavrik, and Hikmet Orhan
- Subjects
high fructose corn syrup ,hippocampus ,learning ,memory ,melatonin ,Medicine - Abstract
Objective(s): We investigated the harmful effects of high fructose corn syrup (HFCS) on learning and memory in the hippocampus and the ameliorative effects of melatonin (Mel). Materials and Methods: Thirty-six adult male Sprague Dawley rats were divided into three groups: Group I, control; Group II, HFCS; and Group III, HFCS+Mel. HFCS form F55 was prepared as a 20% fructose syrup solution. Rats in HFCS and HFCS+Mel groups were given drinking water for 10 weeks. Rats in the HFCS+Mel group have been given 10 mg/kg/day melatonin orally for the 6 weeks, in addition to HFCS 55. The Morris water maze (MWM) test was applied to all animals for 5 days to determine their learning and memory levels. After decapitation, one-half of the hippocampus samples were collected for western blot analysis, and another half of the tissues were collected for histopathological and immunohistochemical analyses. Results: In the HFCS group, there was a significant difference between the time to find the platform in the MWM test and time spent in the quadrant between days 1 and 5 (P=0.037 and P=0.001, respectively). In addition, a decreased level of MT1A receptor, TNF-α, iNOS, osteopontin (OPN), and interleukin-6 (IL-6) expressions were significantly increased in the HFCS group. Melatonin treatment reversed MT1A receptor levels and TNF-α, iNOS, OPN, and IL-6 expressions. During the histopathological examination, increased neuronal degenerations were observed in the HFCS group. Melatonin ameliorated these changes.Conclusion: Consumption of HFCS caused deterioration of learning and memory in adult rats. We suggest that melatonin is effective against learning and memory disorders.
- Published
- 2023
- Full Text
- View/download PDF
3. The impact of moderate-intensity swimming exercise on learning and memory in aged rats: The role of Sirtuin-1
- Author
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Ulker Tunca, Mustafa Saygin, Ozlem Ozmen, Rahime Aslankoc, and Arzu Yalcin
- Subjects
bdnf ,creb ,learning-memory ,sirtuin-1 ,swimming exercise ,Medicine - Abstract
Objective(s): The purpose of this study was to evaluate the effect of moderate-intensity swimming exercise on learning and memory by the Morris water maze test. Changes in the expressions of cyclic AMP-response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) proteins alternative pathway which were activated by sirtuin-1 (SIRT-1) were investigated. Materials and Methods: The study included thirty-two male Sprague-Dawley rats (350-500 g, 11-12 and 15–16 months old). The rats were randomly divided into four groups with 8 rats in each group. The groups were designed as follows: Control-1 (11-12 months), Exercise-1 (11-12 months), Control-2 (15-16 months), Exercise-2 (15-16 months). Moderate-intensity exercise was assigned for 30 min/day, 5 days/week, for the whole training period of 8 weeks. Results: There were statistically significant differences between the groups on the third day (P=0.005) when swim speeds increased in the exercise groups. There was a statistically significant difference between Exercise 1 and Exercise 2 groups, the entries in the platform zone decreased in Exercise 2 group (P=0.026). While there were no histopathological findings observed in any group, increased SIRT-1, BNDF, and CREB expressions were seen in exercise groups compared with control groups.Conclusion: In aged rats exercising at moderate intensity, increased expression of CREB and BDNF, and SIRT-1 could improve hippocampal-dependent memory.
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- 2021
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4. Optimum alkaline treatment parameters for the extraction of cellulose and production of cellulose nanocrystals from apple pomace
- Author
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Melikoğlu, Arzu Yalçın, Bilek, Seda Ersus, and Cesur, Serap
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- 2019
- Full Text
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5. Risk Factors for Mortality in Elderly Patients who Live in Nursing Homes: 8-year Follow-up Period
- Author
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Yasar Kucukardali, Arzu Yalcin Assistant, Murat Hakan Terekeci, Mehmet Akif Ozturk, Betul Kucukardali, and Elif Cigdem Altunok
- Subjects
nursing home ,mortality ,risk factors ,elderly patients ,Medicine - Abstract
Background: In developed countries and our country, the ratio of the elderly to the total population is increasing due to the rise in worldwide medical care spendings and the medical workforce allocated for the treatment of the acute and chronic problems of the elderly. Aims and Objectives: The number of studies based on long-term observations of the risk factors that affect the survival and mortality rates of the elderly in nursing homes is quite rare. Currently, there are no studies concerning this issue in the country. The authors carried out an eight years prospective study to determine the risk factors for mortality in a private nursing home with a capacity of 150 beds located in Istanbul. Materials and Methods: From January 2007 to March 2015, we scanned the number of medications, comorbidities, nutritional status, age, mental score, number of falls and fractures, levels of hemoglobin, albumin, creatinine, and glucose parameters related with mortality in 612 patients admitted to the nursing home. Results: The median overall survival time was 34 months. A total of 240 (39%) residents died within eight years, 44% within two years and 55% within three years. The evaluation results shothat 360 (51%) of the 612 residents, were females and the mean age was 76.49 (± 11.36) years. Hazard ratios of the related parameters that related to mortality were respectively 1,3 for age, 1,5 for BMI less than 20kg/m2, 4,2 for more than six comorbidities, 7,01 for six to nine number of medications, 5 for dependency, 0,7 for one to three episodes of infection, 0,5 for falls, 1,3 for fracture, 3,1 for mental score of less than 18, 1,9 for hemoglobin less than 12gr/dl, 4,03 for creatinine higher than 1.5 mg/dl, 2,43 for glucose greater than 126 mg/dl, 4,8 for albumin less than 3 g/dl (95% CI). Conclusion: The risk factors causing mortality are; old age, BMI less than 20, more than six comorbidities, more than six medications, dependency, one to three episodes of infection, impaired mental score less than 18, anemia, hyperglycemia, kidney failure, hypoalbuminemia at the patients who admitted to nursing homes. Early optimal monitoring of these parameters can provide a positive contribution to the survival of elderly residents in nursing homes.
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- 2019
- Full Text
- View/download PDF
6. Protective effect of melatonin on learning and memory impairment and hippocampal dysfunction in rats induced by high-fructose corn syrup
- Author
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Arzu, Yalcin, Mustafa, Saygin, Ozlem, Ozmen, Oguzhan, Kavrik, and Hikmet, Orhan
- Abstract
We investigated the harmful effects of high fructose corn syrup (HFCS) on learning and memory in the hippocampus and the ameliorative effects of melatonin (Mel).Thirty-six adult male Sprague Dawley rats were divided into three groups: Group I, control; Group II, HFCS; and Group III, HFCS+Mel. HFCS form F55 was prepared as a 20% fructose syrup solution. Rats in HFCS and HFCS+Mel groups were given drinking water for 10 weeks. Rats in the HFCS+Mel group have been given 10 mg/kg/day melatonin orally for the 6 weeks, in addition to HFCS 55. The Morris water maze (MWM) test was applied to all animals for 5 days to determine their learning and memory levels. After decapitation, one-half of the hippocampus samples were collected for western blot analysis, and another half of the tissues were collected for histopathological and immunohistochemical analyses.In the HFCS group, there was a significant difference between the time to find the platform in the MWM test and time spent in the quadrant between days 1 and 5 (P=0.037 and P=0.001, respectively). In addition, a decreased level of MT1A receptor, TNF-α, iNOS, osteopontin (OPN), and interleukin-6 (IL-6) expressions were significantly increased in the HFCS group. Melatonin treatment reversed MT1A receptor levels and TNF-α, iNOS, OPN, and IL-6 expressions. During the histopathological examination, increased neuronal degenerations were observed in the HFCS group. Melatonin ameliorated these changes.Consumption of HFCS caused deterioration of learning and memory in adult rats. We suggest that melatonin is effective against learning and memory disorders.
- Published
- 2022
7. Survival outcomes of percutaneous endoscopic gastrostomy, comparison of cerebrovascular event and non-cerebrovascular event in malnourished patients
- Author
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Sibel Temür, Cengiz Pata, Ferda Fatma Kartufan, Nazlı Şişik Yaltırık, Arzu Yalcin, Rahman Nurmuhammedov, Elif Cigdem Altunok, Murat Hakan Terekeci, Yasar Kucukardali, and Hakan Şilek
- Subjects
medicine.medical_specialty ,Medicine (General) ,RD1-811 ,medicine.medical_treatment ,Gastroenterology ,percutaneous endoscopic gastrostomy ,chemistry.chemical_compound ,R5-920 ,Internal medicine ,White blood cell ,Percutaneous endoscopic gastrostomy ,medicine ,Dementia ,enteral nutrition ,cerebrovascular events ,Prospective cohort study ,Survival rate ,Creatinine ,business.industry ,serebrovasküler olay ,medicine.disease ,enteral beslenme ,Parenteral nutrition ,medicine.anatomical_structure ,chemistry ,perkütan endoskopik gastrostomi ,Medicine ,Surgery ,business ,Body mass index - Abstract
Aim: The number of comorbid diseases increased with the rise in the elderly population. In some cases, the state of deficient or absent nutrition emerges. Nevertheless, the contribution of percutaneous endoscopic gastrostomy (PEG) to the quality of life and the survival rate in the elderly with certain diseases remains controversial. Methods: In this prospective cohort study, patients who underwent percutaneous endoscopic gastrostomy (PEG) procedure between 2009 and 2015 were divided into two groups: CVE group consisted of patients with cerebrovascular event (CVE) and non-CVE group comprised patients who suffered from esophageal tumors, head and neck tumors, brain tumors, amyotrophic lateral sclerosis and terminal dementia. In this study, the patients' pre-PEG and post-PEG body mass index (BMI) values, hemoglobin (Hb), albumin (alb), creatinine (Cr) and C-reactive protein (CRP) values, white blood cell counts, demographic characteristics, 30, 90, 180 and 365 day-survival rates, complications (mechanical, metabolic and infectious) and duration of patency of the PEGs were compared. Results: The average age was lower while survival rate on the 90th day was higher in the CVE group. No significant difference was found in terms of other parameters. At the end of the one-year follow-up, 21% of the patients in the CVE group and 12% of those in the non-CVE group were able to be fed without PEG. Conclusion: PEG patency was higher in the CVE group at 3 months but there was no statistically significant difference between the groups at one-year and overall follow-up periods.
- Published
- 2019
8. Tumor cell heterogeneity in Small Cell Lung Cancer (SCLC): phenotypical and functional differences associated with Epithelial-Mesenchymal Transition (EMT) and DNA methylation changes.
- Author
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Alexander Krohn, Theresa Ahrens, Arzu Yalcin, Till Plönes, Julius Wehrle, Sanaz Taromi, Stefan Wollner, Marie Follo, Thomas Brabletz, Sendurai A Mani, Rainer Claus, Björn Hackanson, and Meike Burger
- Subjects
Medicine ,Science - Abstract
Small Cell Lung Cancer (SCLC) is a specific subtype of lung cancer presenting as highly metastatic disease with extremely poor prognosis. Despite responding initially well to chemo- or radiotherapy, SCLC almost invariably relapses and develops resistance to chemotherapy. This is suspected to be related to tumor cell subpopulations with different characteristics resembling stem cells. Epithelial-Mesenchymal Transition (EMT) is known to play a key role in metastatic processes and in developing drug resistance. This is also true for NSCLC, but there is very little information on EMT processes in SCLC so far. SCLC, in contrast to NSCLC cell lines, grow mainly in floating cell clusters and a minor part as adherent cells. We compared these morphologically different subpopulations of SCLC cell lines for EMT and epigenetic features, detecting significant differences in the adherent subpopulations with high levels of mesenchymal markers such as Vimentin and Fibronectin and very low levels of epithelial markers like E-cadherin and Zona Occludens 1. In addition, expression of EMT-related transcription factors such as Snail/Snai1, Slug/Snai2, and Zeb1, DNA methylation patterns of the EMT hallmark genes, functional responses like migration, invasion, matrix metalloproteases secretion, and resistance to chemotherapeutic drug treatment all differed significantly between the sublines. This phenotypic variability might reflect tumor cell heterogeneity and EMT during metastasis in vivo, accompanied by the development of refractory disease in relapse. We propose that epigenetic regulation plays a key role during phenotypical and functional changes in tumor cells and might therefore provide new treatment options for SCLC patients.
- Published
- 2014
- Full Text
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9. Epigenetic priming of AML blasts for all-trans retinoic acid-induced differentiation by the HDAC class-I selective inhibitor entinostat.
- Author
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Nadja Blagitko-Dorfs, Yi Jiang, Jesús Duque-Afonso, Jan Hiller, Arzu Yalcin, Gabriele Greve, Mahmoud Abdelkarim, Björn Hackanson, and Michael Lübbert
- Subjects
Medicine ,Science - Abstract
All-trans retinoic acid (ATRA) has only limited single agent activity in AML without the PML-RARα fusion (non-M3 AML). In search of a sensitizing strategy to overcome this relative ATRA resistance, we investigated the potency of the HDAC class-I selective inhibitor entinostat in AML cell lines Kasumi-1 and HL-60 and primary AML blasts. Entinostat alone induced robust differentiation of both cell lines, which was enhanced by the combination with ATRA. This "priming" effect on ATRA-induced differentiation was at least equivalent to that achieved with the DNA hypomethylating agent decitabine, and could overall be recapitulated in primary AML blasts treated ex vivo. Moreover, entinostat treatment established the activating chromatin marks acH3, acH3K9, acH4 and H3K4me3 at the promoter of the RARβ2 gene, an essential mediator of retinoic acid (RA) signaling in different solid tumor models. Similarly, RARβ2 promoter hypermethylation (which in primary blasts from 90 AML/MDS patients was surprisingly infrequent) could be partially reversed by decitabine in the two cell lines. Re-induction of the epigenetically silenced RARβ2 gene was achieved only when entinostat or decitabine were given prior to ATRA treatment. Thus in this model, reactivation of RARβ2 was not necessarily required for the differentiation effect, and pharmacological RARβ2 promoter demethylation may be a bystander phenomenon rather than an essential prerequisite for the cellular effects of decitabine when combined with ATRA. In conclusion, as a "priming" agent for non-M3 AML blasts to the differentiation-inducing effects of ATRA, entinostat is at least as active as decitabine, and both act in part independently from RARβ2. Further investigation of this treatment combination in non-M3 AML patients is therefore warranted, independently of RARβ2 gene silencing by DNA methylation.
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- 2013
- Full Text
- View/download PDF
10. Relationship of COVID-19 and Diabetes Mellitus
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Arzu, Yalcin, primary
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- 2020
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11. Antioxidant effects of astaxanthin on electric field stimulated skin and sciatic nerve tissue
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Goktug Eren Aslankoc, Dudu Dilek Yavuz, Arzu Yalcin, Selman Hakkı Altuntaş, Fuat Uslusoy, and Ilker Gunyeli
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medicine.medical_specialty ,Antioxidant ,biology ,Sodium ,medicine.medical_treatment ,chemistry.chemical_element ,General Medicine ,medicine.disease_cause ,Malondialdehyde ,Superoxide dismutase ,chemistry.chemical_compound ,Endocrinology ,chemistry ,Catalase ,Astaxanthin ,Internal medicine ,medicine ,biology.protein ,Sciatic nerve ,Oxidative stress - Abstract
Aim: In this study, we have investigated the oxidative effects of long-term electric field (EF) exposure on the skin and sciatic nerve tissue. It is seen that astaxanthin (AST) can have protective effects on the skin and sciatic nerve tissue with its powerful antioxidant effect. Materials and Methods: Rats are divided into 3 groups as control, EF, and EF + AST, with 10 animals in each group. 0.1 ml 0.9% sodium chloride for 30 days in the control group, 10 kV/m (50 Hz) EF 23 hours a day for 30 days in the EF group, 10 kV/m (50 Hz) EF 23 hours a day for 30 days and 100 mg/kg/day AST in 0.1 ml solution for 30 days in EF + AST group is given by gavage. Skin and sciatic nerve tissue are removed bilaterally and homogenized for biochemical analysis. Malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) enzyme activities are studied in the skin and sciatic nerve. Results: The applied EF increases the MDA levels in the skin and sciatic nerve compared to the control group (p = 0.013, p = 0.011, respectively). While AST treatment decreased MDA levels in the skin and sciatic nerve compared to the EF group (respectively; p = 0.046, p = 0.039), SOD (respectively; p = 0.001, p = 0.009) and CAT (respectively; p = 0.004, p = 0.008) enzyme activities were increased.Conclusion: The results show that AST can be used to treat oxidative stress caused by the electric field due to its antioxidant properties.
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- 2021
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12. The oligodendrocyte lineage transcription factor 2 (OLIG2) is epigenetically regulated in acute myeloid leukemia
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Michael Lübbert, Marlon Kovarbasic, Björn Hackanson, Konstanze Döhner, Julius Wehrle, Ralph Wäsch, Heiko Becker, Mahmoud Abdelkarim, Arzu Yalcin, Lars Bullinger, Andrea Schmidts, Heike L. Pahl, Verena I. Gaidzik, Rainer Claus, and Justus Duyster
- Subjects
0301 basic medicine ,Cancer Research ,Blotting, Western ,Decitabine ,HL-60 Cells ,Biology ,Jurkat cells ,Epigenesis, Genetic ,OLIG2 ,03 medical and health sciences ,chemistry.chemical_compound ,Jurkat Cells ,0302 clinical medicine ,hemic and lymphatic diseases ,Cell Line, Tumor ,Genetics ,medicine ,Humans ,Molecular Biology ,Cell Proliferation ,Regulation of gene expression ,Gene Expression Regulation, Leukemic ,Reverse Transcriptase Polymerase Chain Reaction ,Myeloid leukemia ,Cell Differentiation ,Cell Biology ,Hematology ,U937 Cells ,DNA Methylation ,Oligodendrocyte Transcription Factor 2 ,medicine.disease ,Demethylating agent ,Leukemia ,030104 developmental biology ,chemistry ,Leukemia, Myeloid ,030220 oncology & carcinogenesis ,DNA methylation ,Acute Disease ,Cancer research ,Azacitidine ,RNA Interference ,medicine.drug - Abstract
DNA methylation differences between normal tissue and cancerous tissue resulting in differential expression of genes are a hallmark of acute myeloid leukemia (AML) and can provide malignant cells with a growth advantage via silencing of specific genes, for example, transcription factors. Oligodendrocyte lineage transcription factor 2 (OLIG2) was reported to be differentially methylated and associated with prognosis in AML and, as reported for acute lymphoblastic leukemia and malignant glioma, may play a role in malignant transformation. We report that DNA methylation of OLIG2 is associated with decreased expression of mRNA in AML cell lines and patients. Moreover, in cell lines, decreased mRNA expression also translated into decreased OLIG2 protein expression. Treatment of non-expressing cell lines PL-21 and U-937 with the demethylating agent decitabine resulted in robust re-expression of OLIG2 on mRNA and protein levels. Furthermore, stable overexpression of OLIG2 in non-expressing cell lines Kasumi-1 and U-937, using a lentiviral vector system, led to moderate growth inhibition after 4 days and resulted in signs of differentiation in U-937 cells. Interestingly, although CD34 + cells from healthy donors and 10 of 12 AML patients exhibited no protein expression, OLIG2 was expressed in two patients, both bearing the translocation t(15;17), corresponding to OLIG2 expression in NB-4 cells, also harboring t(15;17). In conclusion, we provide first evidence that OLIG2 is epigenetically regulated via DNA methylation and expressed in a subset of AML patients. OLIG2 may exert antiproliferative activity in leukemia cell lines, and its potential leukemia-suppressing role in AML warrants further investigation.
- Published
- 2017
13. Synthesis, Characterization and, the Heavy Metal Removal Efficiency of MFe2O4 (M=Ni, Cu) Nanoparticles
- Author
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Musa Şahin, Arzu Yalcin, Naim Sezgin, and Yüksel Köseoğlu
- Subjects
Materials science ,Inorganic chemistry ,chemistry.chemical_element ,Nanoparticle ,Zinc ,Pollution ,Copper ,law.invention ,Metal ,Nickel ,Adsorption ,chemistry ,law ,visual_art ,visual_art.visual_art_medium ,Ferrite (magnet) ,Atomic absorption spectroscopy ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The purpose of the study described in this paper was to compare the removal of the heavy metals zinc, nickel, and copper from synthetic wastewater by using nanoparticles of CuFe 2 O 4 and NiFe 2 O 4 . The nanoparticles of nickel and copper ferrite (CuFe 2 O 4 and NiFe 2 O 4 ) were produced by the PEG assisted hydrothermal method. The structural and morphological characterizations were determined using XRD, FT-IR, and SEM. These nanoparticles were dispersed into synthetic wastewater contaminated with zinc, nickel, and copper. Once they had bound to the heavy metals, they were removed from the water solution using a strong magnet. The metal concentrations of the filtered samples were determined by using atomic absorption spectrophotometry (AAS). Then the heavy metal removal efficiencies and adsorption capacities of the nanoparticles (CuFe2O4 and NiFe2O4) were calculated. The removal efficiencies of Cu(II), Ni(II) and Zn(II) by using CuFe2O4 nanoparticles was calculated as 83.50%, 98.85%, and 99.80%, respectively. The removal efficiencies of Cu(II), Ni(II), and Zn(II) by using NiFe2O4 nanoparticles were calculated as 92.55%, 36.56 %, and 99.91%, respectively. The measurements were repeated several times with the same
- Published
- 2013
- Full Text
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14. Evaluating the impact of genetic and epigenetic aberrations on survival and response in acute myeloid leukemia patients receiving epigenetic therapy
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Nadja Blagitko-Dorfs, Claudia Schmoor, Verena I. Gaidzik, Charlotte Schmidt-Salzmann, Björn Hackanson, Lars Bullinger, Michael Lübbert, Konstanze Döhner, Justus Duyster, Arzu Yalcin, Jan K. Hiller, and Mahmoud Abdelkarim
- Subjects
Oncology ,Male ,medicine.medical_specialty ,NPM1 ,Antimetabolites, Antineoplastic ,Azacitidine ,Decitabine ,Biology ,DNA Methyltransferase 3A ,Epigenesis, Genetic ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,medicine ,Biomarkers, Tumor ,Humans ,DNA (Cytosine-5-)-Methyltransferases ,Aged ,Aged, 80 and over ,Performance status ,Hazard ratio ,Myeloid leukemia ,Hematology ,General Medicine ,Middle Aged ,Survival Rate ,Leukemia, Myeloid, Acute ,Treatment Outcome ,030220 oncology & carcinogenesis ,DNA methylation ,Immunology ,Mutation ,Female ,Nucleophosmin ,Epigenetic therapy ,030215 immunology ,medicine.drug - Abstract
Treatment with hypomethylating agents such as decitabine, which results in overall response rates of up to 50%, has become standard of care in older patients with acute myeloid leukemia (AML) who are not candidates for intensive chemotherapy. However, there still exists a lack of prognostic and predictive molecular biomarkers that enable selection of patients who are likely to benefit from epigenetic therapy. Here, we investigated distinct genetic (FLT3-ITD, NPM1, DNMT3A) and epigenetic (estrogen receptor alpha (ERα), C/EBPα, and OLIG2) aberrations in 87 AML patients from the recently published phase II decitabine trial (AML00331) to identify potential biomarkers for patients receiving hypomethylating therapy. While FLT3-ITD and NPM1 mutational status were not associated with survival or response to therapy, patients harboring DNMT3A R882 mutations showed a non-significant association towards shorter overall survival (hazard ratio (HR) 2.15, 95% confidence interval (CI) 0.91–5.12, p = 0.08). Promoter DNA methylation analyses using pyrosequencing also revealed a non-significant association towards shorter overall survival of patients with higher levels of methylation of ERα (HR 1.50, CI 0.97–2.32, p = 0.07) and OLIG2 CpG4 (HR 1.52, CI 0.96–2.41, p = 0.08), while DNA methylation of C/EBPα showed no association with outcome. Importantly, in multivariate analyses adjusted for clinical baseline parameters, the impact of ERα and OLIG2 CpG4 methylation was conserved (HR 1.76, CI 1.01–3.06, p = 0.05 and HR 1.67, CI 0.91–3.08, p = 0.10, respectively). In contrast, none of the investigated genetic and epigenetic markers was associated with response to treatment. Additional to the previously reported adverse prognostic clinical parameters such as patients’ age, reduced performance status, and elevated lactate dehydrogenase levels, DNMT3A R882 mutation status, as well as ERα and OLIG2 CpG4 DNA methylation status, may prove to be molecular markers in older AML patients prior to hypomethylating therapy.
- Published
- 2016
15. The HDAC class I-specific inhibitor entinostat (MS-275) effectively relieves epigenetic silencing of the LAT2 gene mediated by AML1/ETO
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Tobias Berg, Jesus Duque-Afonso, Arzu Yalcin, Olaf Heidenreich, Michael Lübbert, and Mahmoud Abdelkarim
- Subjects
Cancer Research ,Small interfering RNA ,Methyltransferase ,Pyridines ,Methylation ,Epigenesis, Genetic ,chemistry.chemical_compound ,RUNX1 Translocation Partner 1 Protein ,Proto-Oncogene Proteins ,hemic and lymphatic diseases ,Genetics ,Humans ,Gene silencing ,Gene Silencing ,neoplasms ,Molecular Biology ,Transcription factor ,Adaptor Proteins, Signal Transducing ,biology ,Entinostat ,Histone Deacetylase Inhibitors ,Histone ,chemistry ,Acetylation ,Benzamides ,Core Binding Factor Alpha 2 Subunit ,biology.protein ,Cancer research ,Transcription Factors - Abstract
The chromosomal translocation (8;21) fuses the hematopoietic transcription factor AML1 (RUNX1) with ETO (RUNX1T1, MTG8), resulting in the leukemia-specific chimeric protein AML1/ETO. This fusion protein has been implicated in epigenetic silencing, recruiting histone deacetylases (HDACs) and DNA methyltransferases to target promoters. Previously, we have identified a novel in vivo AML1/ETO target gene, LAT2 (NTAL/LAB/WBSCR5), which is involved in FcɛR I, c-Kit, B-cell and T-cell receptor signalling. We have now addressed the molecular mechanisms of AML1/ETO-mediated LAT2 repression. In Kasumi-1 cells, where AML1/ETO bound to the LAT2 gene, small interfering RNA (siRNA)-mediated AML1/ETO depletion caused upregulation of LAT2, suggesting a possible direct mechanism of repression. Expression of AML1/ETO was associated with a decrease in acetylation of histones H3, H3K9 and H4, and an increase in H3K9 and H3K27 trimethylation. The class I-specific HDAC inhibitors entinostat (MS-275) and mocetinostat (MGCD0103) induced LAT2 expression specifically in AML1/ETO-expressing cells, resulting in induction of several activating histone marks on the LAT2 gene, including trimethylation of histone H3K4. The combination of entinostat and decitabine increased acetylation of histones H3 and H4, as well as LAT2 mRNA expression, in an at least additive fashion. In conclusion, several repressive histone modifications mark the LAT2 gene in the presence of AML1/ETO, and LAT2 gene derepression is achieved by pharmacological inhibition of HDACs.
- Published
- 2011
- Full Text
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16. MnFe2O4 nano spinels as potential sorbent for adsorption of chromium from industrial wastewater
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Naim Sezgin, Yüksel Köseoğlu, and Arzu Yalcin
- Subjects
Sorbent ,Materials science ,Waste management ,Scanning electron microscope ,Nanoparticle ,chemistry.chemical_element ,Ocean Engineering ,02 engineering and technology ,010501 environmental sciences ,021001 nanoscience & nanotechnology ,01 natural sciences ,Pollution ,Industrial wastewater treatment ,Chromium ,Adsorption ,Wastewater ,chemistry ,Freundlich equation ,0210 nano-technology ,0105 earth and related environmental sciences ,Water Science and Technology ,Nuclear chemistry - Abstract
In this study, nanospinels of MnFe2O4 were synthesized by a rapid method of microwave-assisted combustion technique for the removal of total chromium from real industrial wastewater. Nanoparticles of MnFe2O4 were characterized by X-ray diffraction and scanning electron microscopy. The removal of total chromium from real industrial wastewater, which was taken from galvanotechnic industry, using of nanospinel MnFe2O4 was investigated. The effects of adsorbent dosage, contact time, and initial concentrations on total chromium removal from wastewater were studied using the real wastewater. Optimal conditions were found for total chromium removal. Chromium removal and adsorption capacity of MnFe2O4 nanoparticles (NPs) were achieved as 59.35% and 89.18 mg/g, respectively. In addition, other optimum conditions of adsorbent dosage and contact time were found as 1.5 g/L and 120 min in this study, respectively. The removal of total chromium using MnFe2O4 NPs was fitted with Freundlich isotherm and pseudo-second-order kinetic models. The results indicated that MnFe2O4 nanospinels are suitable adsorbents for the removal of total chromium from industrial wastewater.
- Published
- 2016
17. Epigenetic priming of AML blasts for all-trans retinoic acid-induced differentiation by the HDAC class-I selective inhibitor entinostat
- Author
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Mahmoud Abdelkarim, Jan K. Hiller, Nadja Blagitko-Dorfs, Yi Jiang, Jesus Duque-Afonso, Michael Lübbert, Gabriele Greve, Björn Hackanson, and Arzu Yalcin
- Subjects
Adult ,Male ,Myeloid ,Pyridines ,Cellular differentiation ,Retinoic acid ,Decitabine ,lcsh:Medicine ,Antineoplastic Agents ,Tretinoin ,Pharmacology ,Biology ,Cell Line ,Epigenesis, Genetic ,chemistry.chemical_compound ,hemic and lymphatic diseases ,medicine ,Humans ,Drug Interactions ,Promoter Regions, Genetic ,lcsh:Science ,neoplasms ,Aged ,Multidisciplinary ,Entinostat ,lcsh:R ,Cell Differentiation ,DNA Methylation ,Middle Aged ,Leukemia, Myeloid, Acute ,medicine.anatomical_structure ,chemistry ,Hypomethylating agent ,DNA methylation ,Benzamides ,Female ,lcsh:Q ,medicine.drug ,Research Article - Abstract
All-trans retinoic acid (ATRA) has only limited single agent activity in AML without the PML-RARα fusion (non-M3 AML). In search of a sensitizing strategy to overcome this relative ATRA resistance, we investigated the potency of the HDAC class-I selective inhibitor entinostat in AML cell lines Kasumi-1 and HL-60 and primary AML blasts. Entinostat alone induced robust differentiation of both cell lines, which was enhanced by the combination with ATRA. This "priming" effect on ATRA-induced differentiation was at least equivalent to that achieved with the DNA hypomethylating agent decitabine, and could overall be recapitulated in primary AML blasts treated ex vivo. Moreover, entinostat treatment established the activating chromatin marks acH3, acH3K9, acH4 and H3K4me3 at the promoter of the RARβ2 gene, an essential mediator of retinoic acid (RA) signaling in different solid tumor models. Similarly, RARβ2 promoter hypermethylation (which in primary blasts from 90 AML/MDS patients was surprisingly infrequent) could be partially reversed by decitabine in the two cell lines. Re-induction of the epigenetically silenced RARβ2 gene was achieved only when entinostat or decitabine were given prior to ATRA treatment. Thus in this model, reactivation of RARβ2 was not necessarily required for the differentiation effect, and pharmacological RARβ2 promoter demethylation may be a bystander phenomenon rather than an essential prerequisite for the cellular effects of decitabine when combined with ATRA. In conclusion, as a "priming" agent for non-M3 AML blasts to the differentiation-inducing effects of ATRA, entinostat is at least as active as decitabine, and both act in part independently from RARβ2. Further investigation of this treatment combination in non-M3 AML patients is therefore warranted, independently of RARβ2 gene silencing by DNA methylation.
- Published
- 2013
18. Impact of Distinct Genetic and Epigenetic Aberrations on Survival and Response in Acute Myeloid Leukemia Patients Receiving Epigenetic Therapy
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Jan K. Hiller, Arzu Yalcin, Verena I. Gaidzik, Michael Lübbert, Lars Bullinger, Mahmoud Abdelkarim, Claudia Schmoor, Charlotte Schmidt-Salzmann, Konstanze Döhner, Nadja Blagitko-Dorfs, Björn Hackanson, and Justus Duyster
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Oncology ,medicine.medical_specialty ,NPM1 ,Performance status ,business.industry ,Immunology ,Hazard ratio ,Decitabine ,Myeloid leukemia ,Cell Biology ,Hematology ,medicine.disease ,Biochemistry ,Leukemia ,Internal medicine ,DNA methylation ,medicine ,business ,Epigenetic therapy ,medicine.drug - Abstract
Background: Treatment with hypomethylating agents such as decitabine, which results in complete and partial remission rates of up to 50%, has become standard of care in older patients with acute myeloid leukemia (AML) who are no candidates for intensive chemotherapy. While clinical parameters such as reduced performance status, high leukocyte counts, elevated lactate dehydrogenase (LDH) levels as well as poor-risk cytogenetics are associated with lower response rates and shorter overall survival, there exists only limited data on molecular biomarkers that enables for selection of AML patients who are likely to benefit from epigenetic therapy. Shen et al. (JCO 2010) could show that distinct DNA methylation changes are prognostic for overall survival in myelodysplastic syndrome patients, however, response to decitabine therapy could not be predicted. Additionally, mutations in the epigenetic-modifier gene DNMT3A were recently reported to be associated with response and survival in AML patients treated with hypomethylating agents, however, while some of these studies revealed a positive association with outcome, other studies showed no association with response and overall survival (Metzeler et al., Leukemia 2012, DiNardo et al., Leuk Lymph 2014, Coombs et al., Blood 2015). Results: In order to contribute further knowledge regarding prognosis and response to hypomethylating therapy in AML patients, we investigated distinct genetic (FLT3-ITD, NPM1, DNMT3A) and epigenetic (estrogen receptor alpha (ERα), C/EBPα and OLIG2) aberrations in 87 AML patients from the recently published phase II decitabine trial (AML00331, Lübbert et al. Haematologica 2012) to identify potential molecular biomarkers. While FLT3-ITD and NPM1 mutational status were not associated with survival or response to therapy, in our cohort patients harboring DNMT3A R882 mutations showed shorter overall survival (hazard ratio (HR): 2.15, 95%-confidence interval (CI): 0.91-5.12, p=0.08). Promoter DNA methylation analyses using pyrosequencing revealed shorter overall survival of patients with higher levels of methylation of ERα (HR: 1.50, CI: 0.97-2.32, p=0.07) and OLIG2 CpG4 (HR: 1.52, CI: 0.96-2.41, p=0.08), while DNA methylation of C/EBPα showed no association with outcome. Importantly, in multivariate analyses adjusted for clinical baseline parameters, the impact of ERα and OLIG2 CpG4 methylation was conserved (HR: 1.74, CI: 1.03-2.96, p=0.04 and HR: 1.61, CI: 0.96-2.71, p=0.07, respectively) whereas the effect of DNMT3A R882 mutations was reduced to HR: 1.94 (CI: 0.79-4.73, p=0.15). In contrast, none of the investigated molecular markers was associated with response to treatment. Conclusion: In addition to the well established adverse prognostic clinical parameters such as patients' age, reduced performance status and elevated LDH levels, we provide further evidence that pretreatment genetic and especially epigenetic analyses including DNMT3A R882 mutation status, as well as ERα and OLIG2 CpG4 DNA methylation status may be potential molecular biomarkers in AML patients undergoing epigenetic therapy. Disclosures Lübbert: Celgene: Other: Travel Funding; Ratiopharm: Other: Study drug valproic acid; Janssen-Cilag: Other: Travel Funding, Research Funding.
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- 2016
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19. MeDIP coupled with a promoter tiling array as a platform to investigate global DNA methylation patterns in AML cells
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Mahmoud Abdelkarim, Clemens Kreutz, Arzu Yalcin, Gregor Klaus, Jens Timmer, Dietmar Pfeifer, Björn Hackanson, and Michael Lübbert
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Regulation of gene expression ,Cancer Research ,Tiling array ,Antigens, CD34 ,HL-60 Cells ,Hematology ,Sequence Analysis, DNA ,Biology ,DNA Methylation ,Leukemia, Myeloid, Acute ,Differentially methylated regions ,Oncology ,CpG site ,DNA methylation ,Cancer research ,Humans ,Immunoprecipitation ,CpG Islands ,Epigenetics ,Methylated DNA immunoprecipitation ,Promoter Regions, Genetic ,Gene ,Oligonucleotide Array Sequence Analysis - Abstract
Hypermethylation of CpGs in promoter regions and subsequent changes in gene expression are common features in acute myeloid leukemia (AML). Genome-wide studies of the methylome are not only useful to understand changes in DNA methylation and gene regulation but also to identify potential targets for antileukemic treatment. Here we performed methylated DNA immunoprecipitation (MeDIP) in the AML cell line HL-60 and donor-derived CD34+ cells, followed by hybridization on a human promoter tiling array. The comparative analysis of HL-60 versus CD34+ cells revealed differentially methylated promoter regions including genes that are frequently methylated in AML, such as p15/INK4B, OLIG2, RARs2 and estrogen receptor. Microarray data was validated by quantitative pyrosequencing. We corroborate previous reports that MeDIP, in our study combined with a promoter tiling array (MeDIP-Chip), is a robust method to identify genes that are differentially methylated in AML cells in a genome-wide manner, and is thus useful to identify new epigenetic targets for therapeutic or prognostic research.
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- 2012
20. The Oligodendrocyte Lineage Transcription Factor 2 (OLIG2) Is Epigenetically Regulated in AML and Suppresses Leukemia Cell Growth
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Gregor Klaus, Julius Wehrle, Arzu Yalcin, Lars Bullinger, Marlon Kovarbasic, Björn Hackanson, Mahmoud Abdelkarim, Verena I. Gaidzik, Heike L. Pahl, Konstanze Doehner, and Michael Lübbert
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Cell growth ,Immunology ,Transcription factor complex ,Promoter ,Cell Biology ,Hematology ,Methylation ,Biology ,Biochemistry ,Molecular biology ,Jurkat cells ,Cancer cell ,DNA methylation ,Epigenetics - Abstract
Introduction: DNA methylation differences between normal and cancer tissue that result in differential expression of genes are a hallmark of acute myeloid leukemia (AML). DNA methylation mediated silencing of specific genes, especially transcription factors, can provide a growth advantage for malignant cells. Global DNA methylation analyses have not only led to a better understanding of AML subgroups and the impact of epigenetic aberrations in leukemogenesis, but also to the identification of new epigenetically regulated genes. We and others have recently identified the oligodendrocyte lineage transcription factor 2 (OLIG2) as differentially methylated in AML cell lines compared with normal bone marrow cells. Aim of the study: With the hypothesis that OLIG2, which is not expressed in normal hematopoiesis, may play a role in cancerogenesis as shown for acute lymphoblastic leukemia (Lin et al., Cancer Res. 2005) and malignant glioma (Mehta et al., Cancer Cell 2011), we sought to further dissect the impact of OLIG2 in AML, implementing functional studies and primary samples. Results: First, in a cohort of 93 AML patients, we could confirm previous results by Kröger et al. (Blood 2008) that OLIG2 is differentially methylated: using pyrosequencing, 37 patients (39.8%) showed methylation levels > 25% (range (r): 26-79%) in the 5 CpG containing amplicon of the OLIG2 promoter region, independent of cytogenetic subgroup. In a small subset of 13 patients where expression-data was available, an inverse correlation between OLIG2 DNA methylation and mRNA expression was significant (r2=0.55, p Interestingly, while CD 34+ cells from two healthy donors and 10 out of 12 AML patients where protein was available, showed no protein expression, OLIG2 was expressed in 2 patients, both bearing the translocation t(15;17). This corresponds well to OLIG2 expression of cell line NB-4, which also harbours t(15;17). Treatment of non-expressing cell lines PL-21 and U937 with 200 nM 5-aza-2'-deoxycytidine led to robust re-expression of OLIG2, both on mRNA and protein level, strongly implicating DNA methylation as a silencing mechanism in a subset of AML. To investigate the relationship between OLIG2 expression and AML cell growth we used a siRNA transient knock-down in OLIG2 expressing cell lines THP-1 and NB-4. While OLIG2 protein expression measured via densitometry could be strongly reduced to 38% and 45% from pre-treatment levels in THP-1 and NB-4 cells, respectively, no change on cell viability or cell growth was detected. However, stable over-expression of OLIG2 using the lentiviral-vector pLeGO-iG in Kasumi-1 cells, led to a significant growth-inhibition of 32.2% (r: 27.0-37.3%) after 5 days and a 47.7% (r: 30.7-64.6%) increase of apoptotic cells (Annexin-V-staining) as compared to control-vector transfected cells. This negative effect on cell proliferation supports our presumption that OLIG2 could act as a growth-regulator in a subgroup of AML. This could be caused by a direct interaction between OLIG2 and a cell cycle regulator or a transcription factor complex. Conclusion: We show that OLIG2 (I) is in part epigenetically regulated via DNA methylation in AML, resulting in an inverse correlation between DNA methylation and expression; (II) can be re-expressed upon demethylating treatment in cell lines, therefore making it an attractive biomarker to study in AML patients treated with demethylating agents; (III) shows antiproliferative activity in leukemia cell lines and thus should be further studied as a potential tumor suppressor in AML. Disclosures Lübbert: Cephalon / TEVA: Travel support Other.
- Published
- 2014
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