Browsing by Author "Kisim, A"

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    Paclitaxel in combination with AT-101 induces apoptosis via supressing Bcl-2, bcl-XL, mcl-1 proteins in human breast cancer cells.
    Cakar, B; Gursoy, P; Atmaca, H; Kisim, A; Bozkurt, E; Uzunoglu, S; Sezgin, C; Sanli, UA; Karabulut, B; Uslu, R; Karaca, B
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    FIBROBLAST GROWTH FACTOR RECEPTOR 2 (FGFR2) POLYMORPHISM STATUS OF TURKISH BREAST CANCER PATIENTS
    Uslu, R; Karaca, B; Atmaca, H; Kisim, A; Cakar, B; Karabulut, B; Sezgin, C; Uzunoglu, S
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    SYNERGISTIC EFFECT OF GOSSYPOL, A COTTON-PLANT SEED, WITH CONVENTIONAL CHEMOTHERAPEUTICS IN MCF-7 CELLS
    Karaca, B; Atmaca, H; Eniseler, AG; Unuvar-Purcu, D; Kisim, A; Karabulut, B; Uzunoglu, S; Uslu, R
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    Effects of exercise on angiogenesis and apoptosis-related molecules, quality of life, fatigue and depression in breast cancer patients
    Ergun, M; Eyigor, S; Karaca, B; Kisim, A; Uslu, R
    The aim of this study was to explore the effects of exercise on angiogenesis and apoptosis-related molecules, quality of life, fatigue and depression in patients who completed breast cancer treatment. Sixty breast cancer patients were randomised into three groups, as supervised exercise group, home exercise group and education group. Angiogenesis and apoptosis-related cytokine levels and quality of life (EORTC QOL-C30: European Organisation for Research and Treatment of Cancer Quality of Life C30), fatigue (Brief Fatigue Inventory) and depression (BDI: Beck Depression Inventory) scores were compared before and after a 12-week exercise programme. After the exercise programme, statistically significant decreases were found in interleukin-8 and neutrophil activating protein-78 levels in the home exercise group (P < 0.05). The education group showed a statistically significant increase in monocyte chemoattractant protein-1 level (P < 0.05). Functional score and global health score of EORTC QOL-C30 in the supervised exercise group and functional score of EORTC QOL-C30 in the home exercise group increased significantly after exercise programme (P < 0.05). BDI score was significantly lower in the supervised exercise group after the exercise programme (P < 0.05). Changes in angiogenesis and apoptosis-related molecules in the study groups suggest a possible effect of exercise on these parameters. Exercise programmes are safe and effective on quality of life and depression in breast cancer patients whose treatments are complete.
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    Enhancing cytotoxic and apoptotic effect in OVCAR-3 and MDAH-2774 cells with all-trans retinoic acid and zoledronic acid: a paradigm of synergistic molecular targeting treatment for ovarian cancer
    Karabulut, B; Karaca, B; Varol, U; Muslu, U; Cakar, B; Atmaca, H; Kisim, A; Uzunoglu, S; Uslu, R
    Background: Ovarian cancer is the most fatal gynecologic malignancies in the world. Although, platinum based treatments are widely used, the disease becomes treatment refractory within two years, and novel treatment options should be searched. All-trans retinoic acid (ATRA) induces growth arrest, differentiation and cell death in some types of cancer cells and its combination with various anticancer agents results in enhanced cytotoxicity. Zoledronic acid is a common bisphosphonate known for its anticancer effects beyond its current use in the treatment of cancer-induced bone disease. We aimed to investigate the possible additive/synergistic effect of both agents in OVCAR-3 and MDAH-2774 ovarian cancer cell lines, since both agents show superiority to conventional cytotoxics in terms of adverse events. Methods: XTT cell proliferation assay was used for showing cytotoxicity. For verifying apoptosis, both DNA Fragmentation by ELISA assay and caspase 3/7 activity measurement were used. OligoGeArray (R) which consists of 112 apoptosis related genes was used to elucidate the genetic changes within cancer cells. To validate our oligoarray results, quantitative real-time PCR was performed on four selected genes that were maximally effected by the combination treatment: lymphotoxin beta receptor (LTBR), myeloid cell leukemia-1 (MCL-1), tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A), TNFRSF1A-associated death domain protein (TRADD). Results: We demonstrated that a novel combination of ATRA and zoledronic acid is a strong inducer of apoptotic related cell death in both ovarian cancer cells. While the combination therapy significantly induced proapoptotic genes such as tumor necrosis factor receptor superfamily (TNFRSF), TRADD and caspase 4, some of the antiapoptotic genes such as members of MCL-1, LTBR, BAG3 and Bcl-2 family members were inhibited. Conclusions: These are the preliminary molecular results of a novel combination treatment of ATRA and zoledronic acid, with fewer side effects as compared to conventional cytotoxic agents. With additional experimental analysis, it may serve as a good option for the treatment of refractory and elderly ovarian cancer patients, for whom there exists very limited choice of treatment.
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    Comparison of XTT and Alamar blue assays in the assessment of the viability of various human cancer cell lines by AT-101 (-/- gossypol)
    Uzunoglu, S; Karaca, B; Atmaca, H; Kisim, A; Sezgin, C; Karabulut, B; Uslu, R
    This study compared the two different commercially available in vitro viability assays: XTT and Alamar blue (AB), to detect anti-proliferative effects of AT-101, a cotton plant extract, on six different human carcinoma cell lines including: prostate (PC-3 and DU-145), breast (MCF-7 and MDA-MB-231), and ovary (OVCAR-3 and MDAH 2774) in a time- and dose-dependent manner. Cells were exposed to AT-101 in the concentration range of 2.5-40 mu M for 24, 48, and 72 h. The AB assay was slightly more sensitive than the XTT assay in the evaluation of AT-101 at 24 h, suggesting that the AB assay might be used for detecting early changes in cell viability as compared to the XTT assay. Moreover, the AB assay showed less intra-assay variability as compared to the XTT. The non-toxic, non-radioactive AB metabolism assay allows rapid assessment of large numbers of samples, with simple equipment and at reduced cost for continuous monitoring of cancer cell viability, and, thus, should be accepted as a suitable alternative viability method.
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    Zoledronic acid in combination with serine/threonine phosphatase inhibitors induces enhanced cytotoxicity and apoptosis in hormone-refractory prostate cancer cell lines by decreasing the activities of PP1 and PP2A
    Cirak, Y; Varol, U; Atmaca, H; Kisim, A; Sezgin, C; Karabulut, B; Uzunoglu, S; Uslu, R; Karaca, B
    OBJECTIVES To investigate if the cytotoxic and apoptotic effect of zoledronic acid (ZA) can be enhanced by the addition of the serine/threonine protein phosphatase inhibitors calyculin A (CA) and okadaic acid (OA) in hormone and drug refractory prostate cancer cells, PC-3 and DU-145. To discover the effect of these combination treatments on phosphatase 1 (PP1) and PP2A protein expression levels in prostate cancer cells. MATERIALS AND METHODS An XTT cell viability assay was used to determine cytotoxicity. Apoptosis was evaluated by enzyme-linked immunosorbent assay (ELISA) using a Cell Death Detection ELISA Plus Kit and verified by measuring caspase 3/7 enzyme activity. The PP1 and PP2A enzyme activities were evaluated by serine/threonine phosphatase ELISA and expression levels of PP1 and PP2A proteins were then re-assessed by Western blot analysis. RESULTS Combination of ZA with either CA or OA showed synergistic cytotoxicity and apoptosis compared with any agent alone in both PC-3 and DU-145 prostate cancer cells. The combination of ZA with phosphatase inhibitors resulted in enhanced suppression of both PP1 and PP2A enzyme activity and protein levels, which was more overt with the ZA/CA combination. CONCLUSION Results from our study increase the translational potential of our in vitro findings and offer the basic rationale for the design of new combinatory strategies with ZA and phosphatase inhibitors for the treatment of prostate cancer, which may become resistant to conventional therapy.
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    Pretreatment with AT-101 enhances tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis of breast cancer cells by inducing death receptors 4 and 5 protein levels
    Kisim, A; Atmaca, H; Cakar, B; Karabulut, B; Sezgin, C; Uzunoglu, S; Uslu, R; Karaca, B
    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the TNF superfamily and has been shown to induce extrinsic pathway of apoptosis in many types of cancer cells. AT-101, an (-)-enantiomer of gossypol, is a potent anticancer agent that is shown to be an inhibitor of Bcl-2/Bcl-XL. In this study, we searched whether pretreatment with either of these drugs would result in the enhancement of apoptosis through induction of death receptors and activation of mitochondrial pathways within breast cancer cells. Human breast cancer (MCF-7 and MDA-MB-231) and normal breast cells (MCF-10A) were treated with drugs alone/in combination/sequentially. XTT cell viability assay was used to evaluate cytotoxicity. For showing apoptosis, both DNA Fragmentation and caspase 3/7 activity measurements were done. ELISA and Western blot analysis were done to assess DR4 and DR5 protein levels. The expression levels of apoptotic proteins were assessed by human apoptosis antibody array. The sequential treatment of AT-101 followed by TRAIL resulted in significant synergistic cytotoxicity and apoptosis. Moreover, pretreatment of breast cancer cells with AT-101 and then with TRAIL caused enhancement of the expression levels of DR4 and DR5 in both cancer cell lines, suggesting that these cells were under strong apoptotic stimuli. These findings all together, strongly suggest that pretreatment with AT-101 enhances TRAIL-induced death-inducing signaling complex resulting in the engagement of the mitochondrial pathway to apoptosis in breast cancer cells. These promising, preliminary results make AT-101 and TRAIL a novel combination treatment candidate for breast cancer.
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    Combination of AT-101/cisplatin overcomes chemoresistance by inducing apoptosis and modulating epigenetics in human ovarian cancer cells
    Karaca, B; Atmaca, H; Bozkurt, E; Kisim, A; Uzunoglu, S; Karabulut, B; Sezgin, C; Sanli, UA; Uslu, R
    We investigated the effects of AT-101/cisplatin combination treatment on the expression levels of apoptotic proteins and epigenetic events such as DNA methyltransferase (DNMT) and histone deacetylase (HDAC) enzyme activities in OVCAR-3 and MDAH-2774 ovarian cancer cells. XTT cell viability assay was used to evaluate cytotoxicity. For showing apoptosis, both DNA Fragmentation and caspase 3/7 activity measurements were performed. The expression levels of apoptotic proteins were assessed by human apoptosis antibody array. DNMT and HDAC activities were evaluated by ELISA assay and mRNA levels of DNMT1 and HDAC1 genes were quantified by qRT-PCR. Combination of AT-101/cisplatin resulted in strong synergistic cytotoxicity and apoptosis in human ovarian cancer cells. Combination treatment reduced some pivotal anti-apoptotic proteins such as Bcl-2, HIF-1A, cIAP-1, XIAP in OVCAR-3 cells, whereas p21, Bcl-2, cIAP-1, HSP27, Clusterin and XIAP in MDAH-2774 cells. Among the pro-apoptotic proteins, Bad, Bax, Fas, phospho-p53 (S46), Cleaved caspase-3, SMAC/Diablo, TNFR1 and Cytochrome c were induced in OVCAR-3 cells, whereas, Bax, TRAILR2, FADD, p27, phospho-p53 (S46), Cleaved caspase-3, Cytochrome c, SMAC/Diablo and TNFR1 were induced in MDAH-2774 cells. Combination treatment also inhibited both DNMT and HDAC activities and also mRNA levels in both ovarian cancer cells. AT-101 exhibits great potential in sensitization of human ovarian cancer cells to cisplatin treatment in vitro, suggesting that the combination of AT-101 with cisplatin may hold great promise for development as a novel chemotherapeutic approach to overcome platinum-resistance in human ovarian cancer.
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    Targeting Bcl-2 Protein to Enhance Chemosensitivity of Hormone Refractory Prostate Cancer Cell Line, DU-145 by a Synergistic Combination of Docetaxel and Gossypol
    Uzunoglu, S; Karaca, B; Atmaca, H; Kisim, A; Karabulut, B; Uslu, R
    Objective: Docetaxel has become the standard of care for hormone-refractory prostate cancer (HRPC), however drug resistance and toxicity are still challenging in daily cancer practice. The anti-apoptotic pathway centered around the Bcl-2 protein might be one of the responsible pathways. Adding a second drug to docetaxel treatment is one of the most common approaches to solve this problem. Gossypol was reported to have potent anticancer activities in prostate cancer. In this study, we searched for the possible synergistic cytotoxic/apoptotic effects of this combination treatment in hormone- and drug resistant prostate cancer cell line, DU-145 via inhibition of Bcl-2 protein. Material and Methods: XTT cell viability assay was used to assess cytotoxicity of the drugs alone and in combination. For verifying apoptosis, Cell Death Detection Elisa Plus Kit and Caspase-Glo 3/7 assay were used. Western Blot analysis for Bcl-2 protein was carried out. Results: A novel drug combination of docetaxel and gossypol resulted in a significant synergistic cytotoxic activity and apoptosis as compared to any single agent alone, in a dose- and time dependent manner, and also significantly reduced Bcl-2 protein levels in DU-145, in doses that can be used clinically. Condusion: Adding gossypol to docetaxel as a combination treatment in HRPC patients might be a solution for taxane resistant patients. Inhibition of Bcl-2 might be one of the underlying routes of activity for this combination.
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    Comparative analysis of XTT assay and xCELLigence system by measuring cytotoxicity of resveratrol in human cancer cell lines
    Atmaca, H; Bozkurt, E; Kisim, A; Uslu, R
    Objective: In vitro preliminary oncological and translational studies are mainly based on evaluating the cytotoxic effects of a specific compound on cultured cells. Resveratrol is a commercially available compound which is originally isolated from the roots of white hellebore and later from Polygonum cuspidatum. The objective of the study was to compare cytotoxicity data of Resveratrol from XTT end point assay with a real-time cell based xCELLigence system in terms of accuracy, sensitivity, speed and reproducibility in a panel of human cancer cell lines. Methods: XTT end point assay and real-time cell based xCELLigence system were used to evaluate cytotoxicity. Cytotoxicity results were verified by monitoring cells under phase-contrast microscope which were treated with IC50 values of resveratrol. Results: Resveratrol decreased cell viability in a time and concentration-dependent manner in all cancer cell lines when tested by both the XTT assay and xCELLigence system. Standard deviations of the xCELLigence data were found to be lower than the data from XTT assay. Conclusion: The data from this study strongly imply that xCELLigence system has higher precision, more enlightening and more reproducible than XTT end point assay.
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    AT-101 acts as anti-proliferative and hormone suppressive agent in mouse pituitary corticotroph tumor cells
    Yurekli, BS; Karaca, B; Kisim, A; Bozkurt, E; Atmaca, H; Cetinkalp, S; Ozgen, G; Yilmaz, C; Uzunoglu, S; Uslu, R; Saygili, F
    Purpose Gossypol, a naturally occurring compound in cottonseeds, has anticancer effects against several tumor cell lines. It has been extensively studied in clinical trials and is well tolerated with a favorable safety profile. AT-101, a derivative of R (-)-gossypol, binds to Bcl-2 family proteins and induces apoptosis in vitro. Although transsphenoidal surgical excision of the pituitary corticotroph adenoma is the gold standard of care, it is not successful all the time. Medical therapy for Cushing's disease still remains a challenge for the clinicians. We aimed to investigate the cytotoxic and apoptotic effects of AT-101 in mouse pituitary corticotroph tumor AtT20 cells. Methods Cytotoxic effect of AT-101 was assessed by XTT cell viability assay. Apoptosis was shown by measuring DNA fragmentation and Caspase-3/7 activity. Changes in mRNA expressions of apoptosis-related genes were investigated by qPCR array after treatment with AT-101. ACTH was measured by ACTH-EIA Kit. Results AT-101 induced cytotoxicity and apoptosis in AtT20 cells. mRNA levels of pro-apoptotic genes such as TNFR-SF-10B, Bid, PYCARD, Caspase-8, Caspase-3, and Caspase-7 were induced by 2.0-, 1.5-, 1.7-, 1.5-, 1.6-, and 2-fold, respectively, in AtT20 cells by AT-101 treatment. Moreover, some of the anti-apoptotic genes such as BCL2L10, NAIP1, and PAK-7 were reduced by 2.1-, 2.3-, 4.0-fold, respectively, in AtT20 cells. AT-101 also decreased ACTH secretion significantly. Conclusion AT-101 induces apoptosis in mouse pituitary corticotroph tumor cells.
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    Effects of Thymus serpyllum Extract on Cell Proliferation, Apoptosis and Epigenetic Events in Human Breast Cancer Cells
    Bozkurt, E; Atmaca, H; Kisim, A; Uzunoglu, S; Uslu, R; Karaca, B
    Thymus (T.) serpyllum (wild thyme) is an aromatic medicinal plant due to its several biological properties, including anticancer activity. Breast cancer is one of the most common malignancies and increasing evidence supports that it is not only a genetic but also an epigenetic disease. Epigenetics investigates changes in gene expression caused by mechanisms that do not involve alterations in DNA sequence. DNA methylation and histone acetylation are the most widely studied epigenetic changes in cancer cells. This study evaluated the effects of T. serpyllum on apoptosis and epigenetic events in breast cancer cells. XTT cell viability assay was used to determine cytotoxicity. DNA fragmentation and caspase 3/7 activity assays were used in the assesment of apoptosis. DNA methyltransferase (DNMT) and histone deacetylase (HDAC) activities were evaluated by ELISA and verified by qRT-PCR. T. serpyllum extract induced significant cytotoxicity in breast cancer cells (MCF-7 and MDA-MB-231) but not in normal cells. It also induced apoptosis and inhibited the DNMT and HDAC activities in MDA-MB-231 cells. In the present study, the first preliminary data on the effects of the methanolic extract of T. serpyllum in normal and breast cancer cells were obtained and suggest that T. serpyllum may be a promising candidate in the development of novel therapeutic drugs for breast cancer treatment.
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    INVESTIGATION OF FGFR2 GENE POLIMORPHISM IN NORMAL AND CANCEROUS TISSUES OF TURKISH BREAST CANCER PATIENTS
    Kisim, A; Karaca, B; Atmaca, H; Purcu, DÜ; Uzunoglu, S; Uslu, R
    Purpose: The aim of the study was to determine if the polymorphism rs2981582 exists in intron 2 of FGFR2 gene in Turkish breast cancer patients and to investigate the correlation between conventional clinicopathological features and gene polymorphism. Materials and Methods: Both normal and tumoral breast tissue samples were obtained from forty-eight breast cancer patients operated at Department of General Surgery, Ege University Hospital between 2008 and 2009 years. Samples were stored in stabilization solution (SABiosciences). DNA samples were isolated by using High Pure PCR Product purification kit (Roche, Mannheim, Germany). FGFR2 rs2981582 was identified by specific primer-probes (TibMolBiol, Germany) and analysed with high resolution melting (HRM) analysis. Results: The genotypic distribution of the 48 patients for CC (wildtype), CT (heterozygote) ve TT (polymorphic) genotypes were found to be % 43,8 (n= 21), % 41,6 (n= 20) and % 14,6 (n= 7), respectively. No difference was observed between normal and tumor tissue samples (p>0,05). Seven patients with polymorphic genotype (TT) showed immunohistochemically high estrogen receptor (ER) expression pattern and all of the polymorphic patients were luminal like subtype. Patients with wild-type genotype (CC) were more likely to have axillary metastases than the polymorphic (TT) group (U= 36,5, p= 0,043). Conclusion: This is the first study investigating the FGFR2 gene polymorphism in Turkish breast cancer patients. Further analysis of the relationship between slowly progressing luminal like subtype breast cancer and FGFR2 gene polymorphism might have implications for diagnosis or therapy of breast cancer.
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    Regulation of apoptosis-related molecules by synergistic combination of all-trans retinoic acid and zoledronic acid in hormone-refractory prostate cancer cell lines
    Karabulut, B; Karaca, B; Atmaca, H; Kisim, A; Uzunoglu, S; Sezgin, C; Uslu, R
    We report that all-trans retinoic acid (ATRA) in combination with zoledronic acid has strong synergistic cytotoxic and apoptotic effects against human hormone- and drug-refractory prostate cancer cells, PC-3 and DU-145, in a time- and dose-dependent manner. We further investigated the effect of the combination treatment on the apoptotic process by both oligoarray and protein array analysis in DU-145 cells, in which the drug combination shows much more strong synergistic effects, as compared to PC-3 cells. Moreover, we have also performed real time-PCR array analysis to validate oligoarray results. We demonstrated that the combination of ATRA and zoledronic acid is a strong inducer of apoptotic related cell death in human androgen-and drug refractory prostate cancer cells DU-145, at either transcriptional or translational levels. While expression of proapoptotic genes such as tumor necrosis factor receptor superfamily (TNFRSF), Bad, Bax, Fas, FADD are induced with the exposure of the combination, expression of antiapoptotic genes or proteins such as members of inhibitor apoptosis family (IAPs), MCL-1, LTBR, p53 and bcl-2 are reduced. Because this novel combination treatment has fewer side effects than is generally the case with conventional cytotoxic agents, this regimen may be a good option for treatment of elderly prostate cancer patients.
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    Enhancement of docetaxel efficacy by zoledronic acid pretreatment in docetaxel-resistant prostate cancer cells (PC-3/R and DU-145/R)
    Surmeli, Z; Bozkurt, E; Ozer, O; Atmaca, H; Kisim, A; Uzunoglu, S; Uslu, R; Karaca, B