Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Article
    Citation - WoS: 8
    Citation - Scopus: 10
    Bioactive Sphingolipids in Docetaxel-Induced Apoptosis in Human Prostate Cancer Cells
    (Elsevier Ltd., 2012) Başsoy, Esen Yonca; Baran, Yusuf
    In this study, we examined the possible roles of ceramide/sphingosine-1-phosphate and ceramide/glucosyleceramide signaling in docetaxel-induced apoptosis by examining expression levels of the glucosyleceramide synthase and sphingosine kinase-1 and ceramide synthase gene family. As confirmed by isobologram analysis, docetaxel in combination with agents that increase intracellular ceramide levels increased the cytotoxic and apoptotic effects of docetaxel synergistically. More importantly, RT-PCR results revealed that expression levels of glucosyleceramide synthase and sphingosine kinase-1 were downregulated and ceramide synthase genes were upregulated in response to docetaxel. This study identifies mechanisms underlying the involvement of ceramide metabolizing genes in docetaxel-induced apoptosis in prostate cancer cells. © 2012 Elsevier Masson SAS.
  • Article
    Citation - WoS: 38
    Citation - Scopus: 47
    Docetaxel/Zoledronic Acid Combination Triggers Apoptosis Synergistically Through Downregulating Antiapoptotic Bcl-2 Protein Level in Hormone-Refractory Prostate Cancer Cells
    (John Wiley and Sons Inc., 2009) Karabulut, B.; Erten, C.; Gül, M. K.; Cengiz, E.; Karaca, B.; Küçükzeybek, Y.; Görümlü, G.; Atmaca, H.; Uzunoğlu, S.; Şanlı, U. A.; Baran, Yusuf; Uslu, R.
    Docetaxel, a semi-synthetic taxane analogue, is used effectively in the treatment of metastatic prostate cancer. Zoledronic acid, the most potent member of bisphosphonates, has shown pleiotropic anti-tumoral effects on prostate cancer cells. We have explored the possible additive/synergistic effects and the apoptotic pathways induced by combination treatment of docetaxel and zoledronic acid in hormone and drug refractory, PC-3 and DU-145 prostate cancer cells. Combination of docetaxel and zoledronic acid synergistically inhibits cell growth in PC-3 and DU-145 cells. Moreover, this effect was due to downregulation of antiapoptotic protein Bcl-2 in PC-3 and DU-145 cells. In conclusion, docetaxel/zoledronic acid combination is potentially a novel and effective approach for the treatment of prostate cancer.
  • Article
    Citation - WoS: 23
    Citation - Scopus: 24
    Proteasome Inhibitor Bortezomib Increases Radiation Sensitivity in Androgen Independent Human Prostate Cancer Cells
    (Elsevier Ltd., 2010) Göktaş, Serdar; Baran, Yusuf; Ural, Ali Uğur; Yazıcı, Sertaç; Aydur, Emin; Başal, Şeref; Avcu, Ferit; Pekel, Aysel; Dirican, Bahar; Beyzadeoğlu, Murat
    Objectives: To investigate the effects of a strong proteasome inhibitor, bortezomib alone or in combination with radiotherapy on androgen-independent DU145 human prostate cancer cells. Proteasomes play important roles in cell cycle, proliferation, apoptosis, angiogenesis, and cellular resistance to chemotherapy and radiotherapy. Methods: Increasing concentrations of bortezomib alone or in combination with radiation were applied to DU145 cells and IC50 values that inhibited cell growth by 50% were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium-bromide assay. Apoptosis was determined using annexin V staining by flow cytometry. mRNA levels of proapoptotic caspase-3 and antiapoptotic Bcl-2 genes were examined by reverse transcriptase polymerase chain reaction. Results: The IC50 value of bortezomib was found to be 28 μm although 400- and 800-cGy radiation decreased the cell proliferation by 14% and 28%, respectively. In 400- and 800-cGy radiation applied DU145 cells, IC50 value of bortezomib decreased to 23- and 12 μm, respectively. Exposure to 5 μm bortezomib for 48 hours caused apoptosis in 35% of the population whereas 800-cGy radiation resulted apoptosis in 14% of cells. However, 42% of DU145 cells that were exposed to 800 cGy and 5 μm bortezomib underwent apoptosis. Reverse transcriptase polymerase chain reaction results showed a significant decrease in mRNA levels of antiapoptotic Bcl-2 gene and an increase in proapoptotic caspase-3 gene expression in the combination group compared to control group. Conclusions: Bortezomib increases radiation sensitivity in androgen-independent human DU145 prostate cancer cells through inhibition of Bcl-2 and induction of caspase-3 genes. © 2010 Elsevier Inc. All rights reserved.