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Öğe A new combination strategy to enhance apoptosis in cancer cells by using nanoparticles as biocompatible drug delivery carriers(Nature Portfolio, 2021) Kucuksayan, Ertan; Bozkurt, Fatih; Yilmaz, Mustafa Tahsin; Sircan-Kucuksayan, Aslinur; Hanikoglu, Aysegul; Ozben, TomrisSome experimental and clinical studies have been conducted for the usage of chemotherapeutic drugs encapsulated into nanoparticles (NPs). However, no study has been conducted so far on the co-encapsulation of doxorubicin (Dox) and epoxomicin (Epo) into NPs as biocompatible drug delivery carriers. Therefore, we investigated if co-encapsulation of doxorubicin (Dox) and/or epoxomicin (Epo) into NPs enhance their anticancer efficiency and prevent drug resistance and toxicity to normal cells. We synthesized Dox and/or Epo loaded poly (lactic-co-glycolic acid) (PLGA) NPs using a multiple emulsion solvent evaporation technique and characterized them in terms of their particle size and stability, surface, molecular, thermal, encapsulation efficiency and in vitro release properties. We studied the effects of drug encapsulated NPs on cellular accumulation, intracellular drug levels, oxidative stress status, cellular viability, drug resistance, 20S proteasome activity, cytosolic Nuclear Factor Kappa B (NF-kappa B-p65), and apoptosis in breast cancer and normal cells. Our results proved that the nanoparticles we synthesized were thermally stable possessing higher encapsulation efficiency and particle stability. Thermal, morphological and molecular analyses demonstrated the presence of Dox and/or Epo within NPs, indicating that they were successfully loaded. Cell line assays proved that Dox and Epo loaded NPs were less cytotoxic to single-layer normal HUVECs than free Dox and Epo, suggesting that the NPs would be biocompatible drug delivery carriers. The apoptotic index of free Dox and Epo increased 50% through their encapsulation into NPs, proving combination strategy to enhance apoptosis in breast cancer cells. Our results demonstrated that the co-encapsulation of Dox and Epo within NPs would be a promising treatment strategy to overcome multidrug resistance and toxicity to normal tissues that can be studied in further in vivo and clinical studies in breast cancer.Öğe Determination of early spectral changes in melanoma cells during epoxomicin-induced apoptotic process(Refik Saydam National Public Health Agency (RSNPHA), 2021) Kucuksayan, Ertan; Sircan-Küçüksayan, AslinurObjective: Determining the changes in the apoptosis process in cells can provide important information for new treatment and drug research. Apoptotic cells undergo a series of subcellular changes that lead to cell shrinkage and fragmentation. Determining these early changes in the apoptotic process depending on time may provide a new perspective to cell culture studies. The aim of this study is to develop a method in which early spectral changes occurring in the apoptosis process of melanoma cells can be determined depending on time. Methods: In this study, epoxomicin (Epo) was used to induce apoptosis in A375 melanoma cell line and apoptotic dose was determined by MTT method. In order to evaluate the early apoptotic process in a time-dependent manner, measurements were made at five different time points (0.5-6 hours) with a fixed Epo dose. DCFH-DA method was used to measure ROS, which is the most important stimulus of apoptosis. Bax amount was determined by Western Blot technique. Spectroscopic measurements were made with a back-reflection spectroscopy experiment setup consisting of spectrometer, tungsten-halogen light source and fiber optic probe. Apoptosis index values were determined from spectra. Results: Early spectral changes were determined with the spectra measured in the apoptosis time of melanoma cells. A significant difference was found in ROS measurements at 2, 4 and 6 hours compared to control. Cell viability was found to be 70% lower than control at 75 and 100 nM Epo doses after 24 hours. Time-dependent Bax levels were found to increase in all Epo groups as an indicator of apoptosis. Spectroscopic apoptosis index value was found to be compatible with ROS and Bax results at all groups. Conclusion: A new approach has been presented in which spectral changes occurring in the early stage of the apoptosis process in cell culture can be determined by back reflection spectroscopy. This approach has the potential to be developed in cell culture studies as a method that can monitor apoptosis over time without interfering with cell culture conditions. © 2021. All Rights Reserved.Öğe Early detection onset of flap failure using near infrared spectroscopy(Taylor and Francis Ltd., 2022) Sircan-Küçüksayan, Aslinur; Özkan, Özlenen; Özkan, Ömer; Kucuksayan, Ertan; Ünal, Kerim; Canpolat, MuratBackground: Near-infrared spectroscopy (NIRS) is widely used to assess flap perfusions by measuring tissue oxygen saturation (StO2). However, the StO2 level for the onset of perfusion failure is still a controversial issue. Aim: This study proposes a new threshold of StO2 level for detecting the onset of perfusion failure as early as possible to increase flap salvage rates. Methods: Twenty patients undergoing flap surgery were included in this study–13 flaps were implemented to cover defects that occurred due to trauma and 7 flaps to hide imperfections that occurred after cancer treatment. Thirteen flaps were in the lower extremity, six in the mandible, and one in the breast. NIRS was used to measure StO2 in 240 flap regions of the 20 patients to determine flap viability using descriptive statistics. Results: The mean StO2 values from healthy flap and control regions were obtained as 81.6% ± 0.36 and 82% ± 0.18, respectively. The lowest StO2 value of 77.2% was defined as the onset of a vascular complication at a probability of 99.74% by subtracting three times the standard deviation from the mean StO2 of healthy flaps. Vascular complications were observed from 21 regions in the four flaps with StO2 values lower than 77.2%, but only one was lost. Conclusion: The threshold value for the onset of perfusion failure was a 5% decrease from the expected value, much lower than previously described thresholds that may facilitate the detection of perfusion failure in the early stage and increase salvage rates in flap revisions. © 2021 Acta Chirurgica Scandinavica Society.Öğe Elevated level of neuroserpin is an indication for the resistance to gambogic acid-induced apoptosis and oxidative stress in triple-negative breast cancer cells(Walter De Gruyter Gmbh, 2024) Kucuksayan, Ertan; Kucuksayan, Hakan; Sozen, Mehmet Enes; Sircan-Kucuksayan, AslinurBackground: The triple-negative breast cancer (TNBC) subtype, characterized by loss of HER2, estrogen, and progesterone receptors, displays aggressive phenotype and poor prognosis compared to other BC subtypes. Since the TNBC cells are devoid of receptors, endocrine therapy is an ineffective option for TNBC patients, necessitating canonical chemotherapy strategies to treat TNBC. It is crucial to use alternative and natural agents to support chemotherapy in TNBC. Objectives: To clarify the molecular mechanism of the tumorigenic effects of gambogic acid (GA) on TNBC cells with different epithelial character since GA has a wide spectrum of anticancer activity for most cancer types. Methods: We determined the cytotoxic dose of GA incubation of TNBC cells (MDA-MB-231 and BT-20 cells) for 24 h. We performed the MTT test and toluidine blue (TB) staining protocol for TNBC cells. We analyzed E-cadherin, N-cadherin, Bax, and neuroserpin mRNAs in both cells by qPCR. We evaluated apoptosis using DAPI staining and assessed the ROS using the 2',7'-dichlorofluorescin diacetate (DCFH-DA) method. Results: We determined the IC50 concentrations of GA in MDA-MB-231 and BT-20 cells to be 315.8 nM and 441.8 nM, respectively. TB staining showed that BT-20 cells survive at excessive cytotoxic doses of GA, while most of the MDA-MB-231 cells were killed. Also, we found that BT-20 cells are more resistant to GA-induced apoptosis and oxidative stress than the MDA-MB-231 cells. qPCR results showed that GA upregulated neuroserpin, an oxidative stress-relieving factor in the BT-20 cells, but not in the MDA-MB-231 cells. Conclusions: The elevated level of neuroserpin could be a predictive marker to determine the development of resistance to chemotherapeutic agents.Öğe Nesfatin-1 as a Potential Biomarker for Ischemic Stroke: A Case-Controlled Study of a Comparative Analysis of Patients with and Without Internal Carotid Artery Stenosis(Mdpi, 2025) Kati, Sennur Delibas; Ozben, Serkan; Kucuksayan, Ertan; Van, Mert; Cilli, Esra Yegin; Yaman, Aylin; Ozben, TomrisObjectives: Recently, the need for early diagnosis of modifiable risk factors involved in the etiology of stroke has been highlighted in the literature. Nesfatin-1 is a peptide expressed in the central nervous system and peripheral tissues and has been used as a biomarker in recent years. This study aimed to determine the association of ischemic stroke with internal carotid artery stenosis according to nesfatin-1 level and whether it could be used as a biomarker. Methods: A total of 118 patients were included in the study. Three groups were defined: acute stroke patients with symptomatic internal carotid artery stenosis, acute stroke patients without internal carotid artery stenosis, and a control group. Nesfatin-1 levels were measured and compared. Results: The median value was 22 pg/mL in acute stroke patients with internal carotid artery stenosis, 24.3 pg/mL in acute stroke patients without internal carotid artery stenosis, and 46.4 pg/mL in the control group. There is a difference between the median values of nesfatin-1 according to the stroke groups with the control group (p < 0.001). When a cut-off value of <= 30.62 was taken for nesfatin-1, an AUC value of 0.773 indicated statistical significance (p < 0.001). Sensitivity was 77.03%, specificity 83.33%, PPV 90.48%, and NPV 63.83%. The main limitations of our study are the small sample size and the fact that the function of nesfatin-1 is not completely known. Conclusions: Although we found that nesfatin-1 levels were lower in ischemic stroke patients compared to controls, its diagnostic potential indicates a moderate discriminatory ability with an AUC value of 0.773. Therefore, whether it is suitable for clinical use will be demonstrated by studies in larger and multicenter cohorts.Öğe Plasma thiol/disulphide homeostasis changes in patients with restless legs syndrome(Walter De Gruyter Gmbh, 2021) Kucuksayan, Ertan; Ozben, Serkan; Tuac, Selma Topaloglu; Koseoglu, Mesrure; Erel, Ozcan; Neselioglu, Salim; Ozben, TomrisObjectives: Restless legs syndrome (RLS) is a common neurological condition. Oxidative stress plays an important role in its pathogenesis. Thiol-disulphide homeostasis (TDH) is a new biomarker of oxidative stress. We studied plasma TDH to determine whether TDH could be used as a new biomarker for RLS and evaluated correlations between TDH and various disease severity rating scales. Methods: A total of 25 RLS patients and 25 healthy controls were included into the study. TDH status was determined using an automated spectrophotometric analysis method and correlations were analyzed between the TDH status and various disease rating scales in the RLS patients. Results: Plasma total (401 +/- 27 mu mol/L) and native thiol (354 +/- 30 mu mol/L) levels were significantly lower, but disulphide level (24 +/- 6 itmol/L) was significantly (<0.0001) higher in the RLS patients compared to the controls (455 +/- 36, 424 +/- 37, 15 +/- 5 mu mol/L, respectively). The disulphide/native thiol and disulphide/total thiol ratios increased, in contrast, native thiol/total thiol ratio decreased significantly in the RLS patients compared to the healthy controls (<0.0001). The disulphide levels correlated positively with age and various rating scores of the RLS patients. International Restless Legs Syndrome Study Group (IRL SSG) rating score and age correlated negatively with the total and native thiol levels. Conclusions: Our findings indicate increased oxidative stress in the RLS patients reflected by decreased native and total thiol, and increased disulphide levels and positive correlations between the disulphide levels and various rating scores. We suggest dynamic TDH status to be used as a novel biomarker for the diagnosis and follow-up of the RLS patients.Öğe Preparation and Characterization of Polyethylene Glycol Functional Hydroxyapatite/Polycaprolactone Electrospun Biomembranes for Bone Tissue Engineering Applications(Korean Fiber Soc, 2021) Yavuz, Emre; Erdem, Ramazan; Kucuksayan, Ertan; Akarsu, Esin; Akarsu, MuratSurfaces of previously synthesized Hydroxyapatite particles (HAP) have been modified with polyethylene glycol functional silane (PEG-400Si). For the surface modification of HAP, firstly, synthesis of PEG-400Si was performed by urethane reaction of hydroxyl and isocyanate groups. Then, HAP was synthesized by sol-gel method. Afterwards, surface modification of HAP was realized with PEG-400Si. SEM, TEM, XRD and FTIR analyses were utilized to characterize the morphology and structural properties of the synthesized and modified particles. Results revealed that the surface of HAP was modified successfully and the crystal structure of HAP was not changed after modification. Electrospinning process was conducted to obtain unmodified and modified HAP incorporated nanofibrous biomembranes and the characteristics and biological performances of these membranes have been compared to each other. SEM analysis presented that defect-free and round shape nanofibers obtained and the fiber diameter ranged from 230 +/- 114 nm to 760 +/- 291 nm. In vitro biological evaluations revealed that all electrospun nanofibrous biomembranes were nontoxic and the one with PCL/PEG-400Si-HAP exhibited greatest cellular protein expression approximately 1.5 times higher than the PCL biomembrane for 24 h, 48 h and 72 h.
