Browsing by Author "Tuğrul B."

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    The role of hydroxytyrosol in health and disease; [Sağlık ve hastalıkta hidroksitirozolün rolü]
    (Istanbul Tip Fakultesi, 2014) Tuğrul B.; Oktay L.M.
    Hydroxytyrosol is a phenolic compound released from the hydrolysis of oleuropein and is present in olive oil, leaf and fruit. Recently, studies on hydroxytyrosol have revealed its strong antioxidant and antiinflamatory effects. In vitro studies conducted in various cancer cell lines and in vivo assays carried out on animals reported strong evidences for its antiinflamatory, antiproliferative and proapoptotic influences. In addition, in cancer it is believed to have inhibitory effects during angiogenesis. Its modulatory role on bone formation and prevention of bone loss has been the attraction of some studies. If the molecular mechanisms and cellular pathways of hydroxytyrosol are elucidated, it will be possible to plan new strategies targeting various disease involved with cancer, inflammatory and cardio-vascular pathologies. In this review, various in vitro and in vivo studies investigating the antioxidant, anticancer, antiinflamatory role of hydroxytyrosol and its inhibitory effects in osteoporosis are discussed. © 2014 Turkish Society for Radiation Oncology.
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    Investigation of effect of Vitamin D receptor, calcium-sensing receptor and β-catenin on cutaneous squamous cell carcinoma; [D vitamini reseptörü, kalsiyuma duyarlı reseptör ve β-katenin'in skuamöz hücreli deri kanseri üzerine etkisinin araştırılması]
    (De Gruyter, 2020) Tuğrul B.; Söylev S.; Temiz P.; Gençoğlan G.
    Background: Cutaneous squamous cell carcinoma (cSCC) is a malignant and invasive tumor which is originated from epidermis with a high incidence among non-melanoma skin cancers. The aim of this study was to determine whether vitamin D receptor (VDR), calcium-sensing receptor (CaSR) and beta catenin (β-catenin) proteins have an effect on cSCC. Materials and methods: VDR, CaSR and β-catenin proteins in tissue samples of cSCC and control group were analyzed by immunohistochemistry (IHC) and Western blotting (WB) method. IHC findings were statistically evaluated. Results: IHC staining density of VDR and β-catenin were higher in cSCC tissue samples than control. The difference between IHC staining density of VDR and β-catenin in the patient and the control groups were statistically significant (p = 0.021, p = 0.021, respectively), but not for CaSR (p = 0.237). While the VDR and β-catenin staining rates obtained by the IHC method could be supported by WB results, the WB bands for CaSR could not be shown. Conclusion: The findings suggest that VDR and β-catenin may have an effect on the disease. Further research is required to better understand the role of VDR and β-catenin together on cSCC. © 2020 De Gruyter. All rights reserved.
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    The effect of DEBIO 1143 usage alone or in combination with tamoxifen on estrogen receptor positive breast cancer cell lines; [DEBIO 1143’ün tek başına veya tamoxifenle kombinasyonunun östrojen reseptörü pozitif meme kanseri hücre hatlarındaki etkisi]
    (Pamukkale University, 2020) Tuğrul B.; İşseven M.
    Purpose: To investigate the effect of increased concentrations of tamoxifen (TAM) and DEBIO 1143 (AT-406) administered alone or in combination on cells in MCF-7 and BT-474 estrogen receptor positive (ER+) breast cancer cell lines. Materials and methods: The effect of tamoxifen and DEBIO 1143 administered alone or in combination on cell viability in MCF-7 and BT-474 cell lines at the 72nd hour was assessed by the XTT test. Multi-parameter apoptosis assay kit was used to display the effect of the alone/combination of TAM and DEBIO 1143 on both cell lines. Fluorescence microscobic analysis was performed. Results: The IC50 value of TAM was 3.8±0.6 micromolar (μΜ) and 18.9±6.7 μΜ in the MCF-7 and BT-474 cell lines, respectively. The IC50 value of DEBIO 1143 was 15±0.5 μM in the MCF-7 cell line. The results related to drug combination were statistically significant for both cell lines (p<0.001). The decrease in cell viability was not associated with apoptosis. Conclusion: In ER+breast cancer cell lines, the combined doses of the TAM and DEBIO 1143 reduced cell viability more than their administration alone. Combined administrations in both cell lines were concluded in a synergistic effect. Further research is needed to determine which cell death type other than apoptosis is associated with a reduction in cell viability caused by combined administration. © 2020, Pamukkale University. All rights reserved.
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    Prion protein-dependent regulation of p53-MDM2 crosstalk during endoplasmic reticulum stress and doxorubicin treatments might be essential for cell fate in human breast cancer cell line, MCF-7
    (Elsevier Inc., 2023) Tuğrul B.; Balcan E.; Öztel Z.; Çöllü F.; Gürcü B.
    In this study, we investigated the effect of doxorubicin and tunicamycin treatment alone or in combination on MDM-, Cul9-and prion protein (PrP)-mediated subcellular regulation of p53 in the context of apoptosis and autophagy. MTT analysis was performed to determine the cytotoxic effect of the agents. Apoptosis was monitorized by ELISA, flow cytometry and JC-1 assay. Monodansylcadaverine assay was performed for autophagy. Western blotting and immunofluorescence were performed to determine p53, MDM2, CUL9 and PrP levels. Doxorubicin increased p53, MDM2 and CUL9 levels in a dose-dependent manner. Expression of p53 and MDM2 was higher at the 0.25 μM concentration of tunicamycin compared to the control, but it decreased at 0.5 μM and 1 μM concentrations. CUL9 expression was significantly decreased only after treatment of tunicamycin at 0.25 μM. According to its glycosylation status, the upper band of PrP increased only in combination treatment. In combination treatment, p53 expression was higher than control, whereas MDM2 and CUL9 expressions were decreased. Combination treatments may make MCF-7 cells more susceptible to apoptosis rather than autophagy. In conclusion, PrP may be important in determining the fate of cell death through crosstalk between proteins such as p53 and MDM2 under endoplasmic reticulum (ER) stress conditions. Further studies are needed to obtain in-depth information on these potential molecular networks. © 2023 Elsevier Inc.