Browsing by Author "Guven, Ummu"

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Double Hit Strategy: Removal of Sialic Acid From the Dendritic Cell Surface and Loading With Cd44+/Cd24- Cell Lysate Inhibits Tumor Growth and Metastasis by Targeting Breast Cancer Stem Cells
(Elsevier, 2022) Acikgoz, Eda; Duzagac, Fahriye; Guven, Ummu; Yigitturk, Gurkan; Kose, Timur; Oktem, Gulperi
Cancer stem cells (CSCs), which represent the root cause of resistance to conventional treatments, recurrence, and metastasis, constitute the critical point of failure in cancer treatments. Targeting CSCs with dendritic cell (DC)-based vaccines have been an effective strategy, but sialic acids on the surface of DCs limit the interaction with loaded antigens. We hypothesized that removal of sialic acid moieties on immature DCs (iDCs) could significantly affect DC-CSC-antigen loading, thereby leading to DC maturation and improving immune recognition and activity. The lysate of CD44+/CD24-/low breast CSCs (BCSCs) was pulsed with sialidase-treated DCs to obtain mature dendritic cells (mDCs). The roles of cytoskeletal elements in antigen uptake and dendritic cell maturation were determined by immunofluorescence staining, flow cytometry, and cytokine measurement, respectively. To test the efficacy of the vaccine in vivo, CSCs tumor-bearing mice were immunized with iDC or mDC. Pulsing DCs with antigen increased the expression levels of actin, gelsolin, talin, WASp, and Arp2, especially in podosome-like regions. Compared with iDCs, mDCs expressed high levels of CD40, CD80, CD86 costimulatory molecules and increased IL-12 production. Vaccination with mDC: i) increased CD8+ and CD4 + T-cell numbers, ii) prevented tumor growth with anti-mitotic activity and apoptotic induction, iii) suppressed metastasis by decreasing Snail, Slug, and Twist expressions. This study reveals for the first time that sialic acid removal and loading with CSC antigens induces significant molecular, morphological, and functional changes in DCs and that this new DC identity may be considered for future combined immunotherapy strategies against breast tumors.
Enhanced G2/M Arrest, Caspase Related Apoptosis and Reduced E-Cadherin Dependent Intercellular Adhesion by Trabectedin in Prostate Cancer Stem Cells
(Public Library Science, 2015) Acikgoz, Eda; Guven, Ummu; Duzagac, Fahriye; Uslu, Ruchan; Kara, Mikail; Soner, Burak Cem; Oktem, Gulperi
Trabectedin (Yondelis, ET-743) is a marine-derived tetrahydroisoquinoline alkaloid. It is originally derived from the Caribbean marine tunicate Ecteinascidia turbinata and currently produced synthetically. Trabectedin is active against a variety of tumor cell lines growing in culture. The present study focused on the effect of trabectedin in cell proliferation, cell cycle progression, apoptosis and spheroid formation in prostate cancer stem cells (CSCs). Cluster of differentiation (CD) 133(+high)/CD44(+high) prostate CSCs were isolated from the DU145 and PC-3 human prostate cancer cell line through flow cytometry. We studied the growth-inhibitory effects of trabectedin and its molecular mechanisms on human prostate CSCs and non-CSCs. DU-145 and PC-3 CSCs were treated with 0.1, 1, 10 and 100 nM trabectedin for 24, 48 and 72 h and the growth inhibition rates were examined using the sphere-forming assay. Annexin-V assay and immunofluorescence analyses were performed for the detection of the cell death. Concentration-dependent effects of trabectedin on the cell cycle were also evaluated. The cells were exposed to the different doses of trabectedin for 24, 48 and 72 h to evaluate the effect of trabectedin on the number and diameter of spheroids. According to the results, trabectedin induced cytotoxicity and apoptosis at the IC50 dose, resulting in a significant increase expression of caspase-3, caspase-8, caspase-9, p53 and decrease expression of bcl-2 in dose-dependentmanner. Cell cycle analyses revealed that trabectedin induces dose-dependent G2/M-phase cell cycle arrest, particularly at high-dose treatments. Three-dimensional culture studies showed that trabectedin reduced the number and diameter of spheroids of DU145 and PC3 CSCs. Furthermore, we have found that trabectedin disrupted cell-cell interactions via E-cadherin in prostasphere of DU-145 and PC-3 CSCs. Our results showed that trabectedin inhibits cellular proliferation and accelerates apoptotic events in prostate CSCs; and may be a potential effective therapeutic agent against prostate cancer.
Ir Spektroskopi Kullanılarak İn Vitro Meme Kanser Kök Hücrelerinin Araştırılması
(2020) Güler, Günnur; Acikgoz, Eda; Oktem, Gulperi; Guven, Ummu
Amaç: Kanser kök hücreleri (KKH), tümör içinde kendi kendilerini yenileme ve diğer hücre tiplerinefarklılaşabilme kapasitesi sebebiyle tümörün başlaması, ilerlemesi, nüksetmesi, metastaz ve terapötikdirence yol açmaktadır. Bu nedenle, meme kanser kök hücrelerinin (MKKH) karakteristik özelliklerininbelirlenmesi gerekmektedir. Bu çalışmanın amacı, MKKH‟lerin akış sitometrisi ile izole edildikten sonraFourier dönüşümlü kızılötesi (FTIR) spektroskopisi kullanarak hücre biyokimyasındakifarklılaşmalarının moleküler seviyede araştırılmasıdır.Gereç ve Yöntem: MCF-7 meme kanser hücre hattındaki CD44+/CD24- yüzey belirteç özelliğigösteren MKKH‟ler akış sitometrisi ile izole edilmiştir. MCF10A, MCF-7 kanser hücre (KH) hattı ve buhattan izole edilen CD44+/CD24- yüzey belirteç özelliklerine sahip MKKH‟'ler %0,9 NaCI içerisineresuspanse edildikten sonra FTIR spektrometre ile ölçülmüştür.Bulgular: MCF-7 içerisindeki CD44+/CD24- yüzey belirteç özelliğine sahip KKH‟lerinin sort oranı%2,0-2,3 olarak belirlenmiştir. Elde edilen FTIR spektrumlarında, MKKH, meme kanser hücreleri (KH,non-KKH, bulk populasyon) ve sağlıklı hücreler arasında spektral benzerlikler ve farklılıklar tespitedilmiştir. MKKH‟lerde lipit ve protein sinyalleri daha güçlü olup hücre zarı akışkanlığı ve dinamiğifazladır. Sağlıklı hücreler ile kıyaslandığında, KH‟lerde α-helikal proteinler ve DNA sinyallerindeazalmaya karşın negatif yüklü karboksil gruplarından kaynaklanan sinyallerde artış gözlenmektedir. Buveriler, MKKH‟lerin, sağlıklı ve KH‟lere kıyasla yapı, içerik ve dinamiği bakımından oldukça farklı birprofil sergilediğini göstermektedir.Sonuç: Bu çalışma, MKKH‟lerinin moleküler yapısı ve içeriğindeki değişikliklerin incelemesi vasıtasıylaterapötik hedefli ilaç çalışmaları yapılabileceğini ortaya koymaktadır. FTIR spektroskopisi boyar maddegerektirmeden, hassas ve hızlı ölçüm alınması, örnek hazırlamada kolaylık ve az miktarda örnekgerektirmesi sebebiyle ileri hücre çalışmalarında ve medikal alanda biyolojik örneklerin analizlerindekullanılabileceği de gösterilmiştir.
New Psychoactive Substance 5-Meo in Vivo Acute Toxicity and Hystotoxicological Study
(Galenos Publ House, 2021) Altunci, Yusuf Ali; Aydogdu, Melike; Acikgoz, Eda; Guven, Ummu; Dukagac, Fahriye; Atasoy, Asli; Akgur, Serap Annette
Background: The hallucinogenic tryptamine analog 5-methoxy-N-methyl-N-isopropyltryptamine (5-MeO-MiPT) causes social problems worldwide. There are several studies on the metabolism; however, not more studies were found in the literature on acute toxicity. Aims: To report the acute toxicity of 5-MeO-MiPT in mice, followed by quantitative toxicological analysis of blood and organs, hystotoxico-logical and immunohistochemical analysis of tissues and cells. Study design: Animal experiment Methods: In vivo experiments were performed using CD1 adult female mice (n=26). Animals were caged in 4 groups randomly. First group was a control (n=3). Second group was vehicle control (n=3) and injected 150 mu L of blank solution (50% dimethyl sulfoxide in saline /0.9% of NaCl). While for acute toxicity experiments, 5-MeO-MiPT was added to a blank solution in order to obtain a dose of 0.27 mg/kg in 150 mu L injection (n=10) and the last group were injected 2.7 mg/kg 5-MeO-MiPT in a 150 mu L injection (n=10). Quantitative toxicological analysis, hystotoxicological and immunohistochemical analysis were performed. Results: In the toxicological analysis, 5-MeO-MiPT was found negative in biological samples which were control, vehicle control, and 0.27 mg/kg dose mice groups. 5-MeO-MiPT was found 2.7-13.4 ng/mL in blood, 11-29 ng/g in kidney, 15.2-108.3 ng/g in liver, and 1.5-40.6 ng/g in the brain in 2,7 mg/kg injected group. In a low dose of the 5-MeO-MiPT liver section, compared with normal tissues, the difference in staining was statistically significant (p<0.0001). In high-dose of 5-MeO-MiPT, H-score showed that the increase in the number of Caspase-3 positive cells was significant compared to the control (p<0.05). In high-dose of 5-MeO-MiPT, intense Caspase-3 immunoreactivity was observed and the increase in the number of Caspase-3 positive cells compared to the control was statistically significant (p<0.05). In brain section, the statistics of the results obtained from the H-score showed that the increase in the number of Caspase-3 positive cells was significant compared to the control (p=0.0183). In vehicle control liver section, there were few Caspase-8 positive cells characterized by a light brown appearance (p=0.0117). In the high-dose 5-MeO-MiPT group, the numbers of positive cells at low and high doses of 5-MeO-MiPT group were statistically significant compared to the control (p<0.05). In the high-dose 5-MeO-MiPT group, Caspase-8 immunoreactivity was detected in the glomerular structures. Compared to control, the increase in Caspase-8 immunoreactivity was found to be statistically significant (p<0.05). Conclusion: Low-dose 5-MeO-MiPT did not cause any serious histopathological effects on the liver, kidney, and brain. High doses induce apoptotic cell death through caspase activity.
Repression of the Notch Pathway Prevents Liver Damage in Streptozotocin-Induced Diabetic Mice
(Via Medica, 2017) Acikgoz, Eda; Aktug, Huseyin; Yigitturk, Gurkan; Demir, Kenan; Guven, Ummu; Duzagac, Fahriye; Oktem, Gulperi
Introduction. Sunitinib is an oral inhibitor of vascular endothelial growth factor that is used to treat a variety of cancer. There are limited data regarding the effect of sunitinib on diabetes. In the liver, Notch signaling plays an important role in liver tissue development and homeostasis and its dysfunction is associated with liver pathologies. The aim of the present study is to investigate the effects of sunitinib on streptozotocin (STZ)-induced diabetic liver in mice models. Material and methods. An experimental diabetes mellitus (DM) model was created in 28 male CD-1 mice. Twenty-eight male CD-1 mice divided in four groups (n = 7 each) were used; control mice (C), control mice treated with sunitinib (C + S), diabetic mice (DM), and diabetic mice treated with sunitinib (DM + S) for four weeks. The histopathological changes in the liver were examined by histochemistry and immunohistochemistry. Immunoreactivity of Notch1, Jagged1, DLL-1 and VEGF were evaluated in control and diabetic mice after sunitinib treatment. Results. The significant morphological changes in the liver were mostly seen in hepatocytes that were hypertrophied in the DM mice, with an increased amount of eosinophilic granules; moreover, some hepatocytes contained empty vacuole-like structures. The livers of the DM mice revealed increased deposition of collagen fibers. After sunitinib treatment the hepatocytes and hepatic lobules had almost similar morphology to control mice. The immunoreactivities of Notch1, Jagged1, DLL-1 and VEGF in hepatocytes were significantly lower in the DM group when compared with the C, DM + S and C + S group treated with sunitinib. Conclusions. These results suggest that sunitinib effectively protects the liver from diabetes-induced damage through the inhibition of the Notch pathway.
Ribosome Biogenesis Mediates Antitumor Activity of Flavopiridol in Cd44+ Breast Cancer Stem Cells
(Spandidos Publ Ltd, 2017) Erol, Ayse; Acikgoz, Eda; Guven, Ummu; Duzagac, Fahriye; Turkkani, Ayten; Colcimen, Nese; Oktem, Gulperi
Flavopiridol is a synthetically produced flavonoid that potently inhibits the proliferation of human tumor cell lines. Flavopiridol exerts strong antitumor activity via several mechanisms, including the induction of cell cycle arrest and apoptosis, and the modulation of transcriptional regulation. The aim of the present study was to determine the effect of flavopiridol on a subpopulation of cluster of differentiation (CD)44(+)/CD24(-) human breast cancer MCF7 stem cells. The CD44(+)/CD24(-) cells were isolated from the MCF7 cell line by fluorescence-activated cell sorting and treated with 100, 300, 500, 750 and 1,000 nM flavopiridol for 24, 48 and 72 h. Cell viability and proliferation assays were performed to determine the inhibitory effect of flavopiridol. Gene expression profiling was analyzed using Illumina Human HT-12 v4 Expression BeadChip microarray. According to the results, the half maximal inhibitory concentration (IC50) value of flavopiridol was 500 nM in monolayer cells. Flavopiridol induced growth inhibition and cytotoxicity in breast cancer stem cells (BCSCs) at the IC50 dose. The present study revealed several differentially regulated genes between flavopiridol-treated and untreated cells. The result of the pathway analysis revealed that flavopiridol serves an important role in translation, the ribosome biogenesis pathway, oxidative phosphorylation, the electron transport chain pathway, carbon metabolism and cell cycle. A notable result from the present study is that ribosome-associated gene expression is significantly affected by flavopiridol treatment. The data of the present study indicate that flavopiridol exhibits antitumor activity against CD44(+)/CD24(-) MCF7 BCSCs through different mechanisms, mainly by inhibiting translation and the ribosome biogenesis pathway, and could be an effective chemotherapeutic molecule to target and kill BCSCs.