Browsing by Author "Karaca B."
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Item Profiling of angiogenic cytokines produced by hormone- And drug-refractory prostate cancer cell lines, PC-3 and DU-145 before and after treatment with gossypol(2008) Karaca B.; Kucukzeybek Y.; Gorumlu G.; Erten C.; Gul M.K.; Cengiz E.; Atmaca H.; Uzunoglu S.; Sanli U.A.; Karabulut B.; Uslu R.In this study, we aimed to investigate the angiogenic cytokine profiles of hormone- and drug- refractory prostate carcinoma cell lines, PC-3 and DU-145. We also studied the effect of gossypol, a natural polyphenolic cotton-seed extract, on the angiogenic cytokine profile of these cell lines. XTT cell proliferation assay was used for the assessment of cytotoxicity. For apoptosis, both histone-DNA fragmentation by ELISA assay and caspase 3/7 activity measurement were used. Angiogenic cytokine profiles of supernatants from both cell lines, before and after treatment with gossypol, were investigated using the human angiogenesis antibody array I®. It was shown that the two different hormone- and drug-resistant prostate cancer cell lines, PC-3 and DU-145, constitutively express some important angiogenic cytokines, which are known to regulate tumorigenic- ity and angiogenesis in hormone-refractory prostate cancer. However, PC-3 and DU-145 cells have distinct angiogenic cytokine profiles. In addition, these two cells lines respond differently to gossypol treatment in terms of cytotoxicity and angiogenic cytokine secretion. After treatment with 10 μM of gossypol, there was a 1.5-fold decrease in angiogenin and IL-8 levels and a 1.7- and 1.8-fold decrease in ENA-78 and GRO-α levels respectively, in DU-145 cells. For PC-3 cells, there were 1.6- and 1.8-fold decreases in IL-8 and VEGF levels, respectively. We conclude that PC-3 and DU-145 cells secrete significant amounts of different angiogenic cytokines that may explain their aggressive nature and metastatic potential. Gossypol treatment affects angiogenic cyto- kine secretion from these two cell lines in a different manner. By expanding our knowledge of the heterogeneous biological behavior of these two cell lines, novel treatment approaches can be developed for the treatment of prostate cancer.Item Enhancement of docetaxel-induced cytotoxicity and apoptosis by all-trans retinoic acid (ATRA) through downregulation of survivin (BIRC5), MCL-1 and LTbeta-R in hormone- and drug resistant prostate cancer cell line, DU-145(2008) Kucukzeybek Y.; Gul M.K.; Cengiz E.; Erten C.; Karaca B.; Gorumlu G.; Atmaca H.; Uzunoglu S.; Karabulut B.; Sanli U.A.; Uslu R.Background. The management of hormone-refractory prostate cancer (HRPC) still remains as an important challenge of daily oncology practice. Docetaxel has proved to be a first line treatment choice. All-trans retinoic acid (ATRA) could potently inhibit the growth of prostate cancer cells in vitro and its combination with various anticancer agents results in increased cytotoxicity. Based on these data, our aim was to examine the synergistic/additive cytotoxic and apoptotic effects of combination of docetaxel and ATRA, in hormone- and drug refractory human DU-145 prostate cancer cells. Furthermore, we have searched for the underlying mechanisms of apoptosis by demonstrating apoptosis-related genes. 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. For detecting the mechanism of apoptosis induced by docetaxel-ATRA combination, OligoGeArray® which consists of 112 apoptosis related genes was used. Results. Our results revealed that docetaxel and ATRA were synergistically cytotoxic and apoptotic in DU-145 cells, in a dose- and time dependent manner. It was also shown by our studies that apoptosis was induced in DU-145 prostate carcinoma cells with significant cytotoxicity, no matter which agent applied first. We have found out that docetaxel-ATRA combination significantly downregulates survivin (BIRC5), myeloid cell leukemia-1 (MCL-1) and lymphotoxin β-receptor (LTβR) genes, which all three have pivotal roles in regulation of apoptosis and cell cycle progression. Conclusion. In conclusion, we strongly suggest that docetaxel and ATRA combination is a good candidate for this challenging era of daily oncologic practice. Also, the combination of docetaxel and ATRA might allow a reduction in docetaxel doses and by this way may diminish docetaxel adverse effects while maintaining the therapeutic effect in patients with HRPC. © 2008 Kucukzeybek et al; licensee BioMed Central Ltd.Item Regulation of growth factors in hormone- and drug-resistant prostate cancer cells by synergistic combination of docetaxel and octreotide(2009) Erten C.; Karaca B.; Kucukzeybek Y.; Gorumlu G.; Cengiz E.; Gul M.K.; Atmaca H.; Uzunoglu S.; Karabulut B.; Sanli U.A.; Uslu R.OBJECTIVE To evaluate the effects of combined treatment with docetaxel and octreotide, a somatostatin analogue, on human hormone- and drug-refractory prostate cancer cell lines, PC-3 and DU-145, and on some growth factors related to tumour growth and angiogenesis in prostate cancer. MATERIALS AND METHODS A cell proliferation assay was used to assess the cytotoxicity of the drugs. To verify apoptosis, both DNA fragmentation (by enzyme-linked immunosorbent assay) and caspase 3/7 activity were measured. We also investigated the effect of combined docetaxel and octreotide on growth factors secreted from prostate cancer cells using a human growth factor antibody array. RESULTS The combination of docetaxel and octreotide resulted in significant synergistic cytotoxic activity and apoptosis, which was dose- and time-dependent. The combined treatment also resulted in significantly less secretion of stem cell factor and platelet-derived growth factor-AB in PC-3 cells, and transforming growth factor-β and basic fibroblast growth factor in DU-145 cells, than in untreated controls. CONCLUSION Octreotide, a somatostatin analogue, combined with docetaxel might provide a rationale treatment option for hormone-refractory prostate cancer cells, not only by direct inhibition of cell proliferation but also by inhibiting the secretion of growth factors. © 2009 BJU International.Item Combined gossypol and zoledronic acid treatment results in synergistic induction of cell death and regulates angiogenic molecules in ovarian cancer cells(2009) Atmaca H.; Gorumlu G.; Karaca B.; Degirmenci M.; Tunali D.; Cirak Y.; Purcu D.U.; Uzunoglu S.; Karabulut B.; Sanli U.A.; Uslu R.In the present study, we aimed to evaluate the possible synergistic, cytotoxic effects of combination treatment of gossypol and zoledronic acid, in human ovarian cancer cell lines, OVCAR-3 and MDAH-2774, and to elucidate the role of this novel combination treatment on angiogenesis-related molecules in ovarian cancer. The XTT cell viability assay was used for showing cytotoxicity. Both DNA fragmentation by ELISA assay and caspase 3/7 activity measurement were used for demonstrating apoptosis. To elucidate the angiogenic molecules affected by combination treatment, mRNA levels of angiogenic molecules were measured using the Human Angiogenesis RT2 Profiler™ PCR Array (SuperArray, Frederick, MD) in ovarian cancer cell lines, OVCAR-3 and MDAH-2774.The combined treatment resulted in significant, synergistic cytotoxicity, and induced apoptosis. This effect was observed to happen in a dose- and time-dependent manner. Moreover, the combination treatment of 10 μM gossypol and 5 μM zoledronic acid resulted in significant down-regulation (≥ thee-fold) in mRNA levels of some pivotal angiogenic molecules in OVCAR-3 and MDAH-2774 cells as compared to the untreated control. However, this effect was different in the two ovarian cancer cell lines observed. Gossypol, in combination with zoledronic acid, may provide a rational treatment option for ovarian cancer, not only by direct inhibition of cell proliferation, but also inhibition of angiogenesis-related molecules.Item Enhancement of taxane-induced cytotoxicity and apoptosis by gossypol in human breast cancer cell line MCF-7(2009) Karaca B.; Atmaca H.; Uzunoglu S.; Karabulut B.; Sanli U.A.; Uslu R.Purpose: Gossypol is a natural polyphenolic compound extracted from cotton plant (Gossypium species) which has shown potent inhibitory effect on cell growth of many types of cancers. In this study, we aimed to evaluate the interaction of gossypol with some conventional drugs known to be effective in the treatment of breast cancer, like taxanes, doxorubicin, gemcitabine, cisplatin and vinorelbine, in MCF-7 breast cancer cells. Materials and methods: The XTT viability assay was used to evaluate the cytotoxicity of various cytotoxic agents alone and in combination with gossypol in MCF-7 breast cancer cells. The combination effect analysis of Chou and Talalay was used to identify the most synergistic drug combinations. The possible synergistic effects of the combination of drugs on apoptosis were also evaluated by using two different apoptosis assays. Results: We identified strong synergistic cytotoxic and apoptotic activity of gossypol with taxanes among all other studied cytotoxic drugs. Conclusion: This study provides proof that gossypol combined with taxanes may have potential as a novel future treatment for breast cancer. © 2009 Zerbinis Medical Publications.Item The effect of racemic gossypol and AT-101 on angiogenic profile of OVCAR-3 cells: A preliminary molecular framework for gossypol enantiomers(2009) Varol U.; Karaca B.; Tunali D.; Degirmenci M.; Cirak Y.; Purcu D.U.; Uzunoglu S.; Sezgin C.; Karabulut B.; Sanli U.A.; Uslu R.Aim: To compare the effect of racemic gossypol with its (-)/(-) enantiomer (AT-101) on expression profiles of angiogenic molecules by mRNA levels in human ovarian cancer cell line OVCAR-3. Methods: Cell viability assay (2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide) was used to detect cytotoxicity of gossypol enantiomers. DNA fragmentation by an enzyme-linked immunosorbent (ELISA) assay was used to evaluate the rate of apoptosis. The mRNA expression levels of angiogenic molecules were investigated by Human Angiogenesis RT2 Profiler™ PCR Array (SuperArray, Frederick, MD). Results: Both racemic form and AT-101 resulted in a significant cytotoxicity and induced apoptosis. This effect was observed in a dose- and time dependent manner. However, AT-101 was much more potent. In addition, the treatment of 10 μM of racemic gossypol alone and 3 μM of AT-101 alone resulted in significant down-regulation (≥ 3 fold) in mRNA levels of some pivotal angiogenic molecules in OVCAR-3, but altered gene profiles were different by the treatment of each enantiomer. Conclusion: The efficacy of two gossypol enantiomers in OVCAR-3 cells showed distinction. AT-101 was much more potent than racemic gossypol, not only by means of cell death and apoptosis, but also by modulation of angiogenic molecules released from OVCAR-3 cells. Further studies with endothelial cells should be done to verify the anti-angiogenic effect of gossypol enantiomers in cancer treatment.Item Radiosensitization of hormone-refractory prostate cancer cells by gossypol treatment(2010) Akagunduz O.; Karaca B.; Atmaca H.; Uzunoglu S.; Karabulut B.; Sanli U.A.; Haydaroglu A.; Uslu R.Purpose: Many drugs have been tested to increase the sensitivity of prostate cancer cells to radiotherapy. Gossypol, a natural polyphenols compound extracted from the cotton plant, is one of the agents the efficacy of which has been investigated in the treatment of prostate cancer for this purpose. The main aim of this study was to investigate the best gossypol application with irradiation, when gossypol was applied either sequentially (24 h before and after irradiation) or concurrently in PC-3 hormone-refractory and radioresistant prostate cancer cells. Methods: The XTT viability assay was used to evaluate the cytotoxicity of different concentrations of gossypol in PC-3 cells. Irradiation was applied to PC-3 cells via 6 MV photon linear accelerator and delivered 24 h before, 24 h after radiation or at the same time with gossypol administration. Results: Gossypol caused radiosensitization of PC-3 cells that are known to be radioresistant, with high Bcl-2 levels. Among different applications of gossypol and irradiation (before, after and concurrent) in prostate cancer cells, the best results were observed by the application of gossypol 24 h before irradiation. Conclusion: Our study suggests that gossypol represents a promising novel anticancer treatment for radiosensitization of human hormone-refractory prostate cancer cells. © 2010 Zerbinis Medical Publications.Item Comparison of XTT and Alamar blue assays in the assessment of the viability of various human cancer cell lines by AT-101 (-/- gossypol)(2010) 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 2.540 M for 24, 48, and 72h. The AB assay was slightly more sensitive than the XTT assay in the evaluation of AT-101 at 24h, 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. © 2010 Informa Healthcare USA, Inc.Item 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(2010) Karabulut B.; Karaca B.; Varol U.; Muslu U.; Cakar B.; Atmaca H.; Ksm 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® 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. © 2010 Karabulut et al; licensee BioMed Central Ltd.Item Overcoming drug resistance in hormone-and drug-refractory prostate cancer cell line, PC-3 by docetaxel and gossypol combination(2010) Cengiz E.; Karaca B.; Kucukzeybek Y.; Gorumlu G.; Gul M.K.; Erten C.; Atmaca H.; Uzunoglu S.; Karabulut B.; Sanli U.A.; Uslu R.Drug resistance is a significant challenge of daily oncology practice. Docetaxel and gossypol both have antitumoral activity in hormone-refractory prostate cancer (HRPC). Our results revealed that docetaxel and gossypol were synergistically cytotoxic and apoptotic in PC-3 cells in a dose-and time-dependent manner. We further investigated the expression profiles of genes involved in drug resistance and metabolism with a Human Cancer Drug Resistance and Metabolism PCR Array® (SuperArray). Six of the 84 genes that are known to regulate drug resistance, metabolism, cell cycle, DNA repair and oncogenesis were downregulated C3-fold change by the combination treatment. These results may be important in devising mechanism-based and targeted therapeutic strategies for prostate cancer, especially in devising combination therapy for drug resistant prostate cancers. © Springer Science+Business Media B.V. 2009.Item High-resolution melting analysis for screening of Turkish germline mutations in BRCA1 and BRCA2; [Türk hasta popülasyonunda BRCA1 ve BRCA2 germline mutasyonlarïnïn high resolution melting analizi ile taranması](UHOD - Uluslararasi Hematoloji Onkoloji Dergisi, 2010) Purcu D.U.; Karaca B.; Kapkac M.; Ozdemir N.; Uzunoglu S.; Uslu R.The germline mutations of breast cancer susceptibility genes 1 (BRCA1) and 2 (BRCA2) are the two most frequently mutated genes in inherited breast and ovarian cancer. Among the most known mutations in these tumor suppressor genes are 5382insC and 185delAG in BRCA1 and 6174delT in BRCA2. The aim of the current study was to investigate the frequency of these BRCA1 and BRCA2 mutations in Western Turkish population. Twenty-five women with a history of self breast cancer and family history, 25 women with a familial history of breast cancer in their first degree-relatives and five healthy women formed the studied groups. DNA from peripheral blood was extracted and analyzed by high-resolution melting (HRM) analysis. None of the 50 patients and five healthy individuals was found to carry 185delAG mutation in BRCA1 and the 6174delT mutation in BRCA2. But, we found the 5382insC mutation in exon 20 of BRCA1 in five patients, having a strong family history. Four of these five patients were from the same family. Our preliminary results indicate that penetrance of 5382insC mutation in BRCA1 mutations is dominant in Turkish population; however, it seems there might be some other genes that contribute more significantly to familial breast carcinoma in Turkish population in BRCA.Item Regulation of apoptosis-related molecules by synergistic combination of all-trans retinoic acid and zoledronic acid in hormone-refractory prostate cancer cell lines(2011) 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. © 2010 Springer Science+Business Media B.V.Item 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(2012) Kisim A.; Atmaca H.; Cakar B.; Karabulut B.; Sezgin C.; Uzunoglu S.; Uslu R.; Karaca B.Purpose: 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. Methods: 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. Results: 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. Conclusions: 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. © Springer-Verlag 2012.Item Effects of Thymus serpyllum extract on cell proliferation, apoptosis and epigenetic events in human breast cancer Cells(2012) 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 MDAMB-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. Copyright © 2012, Taylor & Francis Group, LLC.Item 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(2012) 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 enzymelinked immunosorbent assay (ELISA) using a Cell Death Detection ELISA Plus Kit and verifi ed 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 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 andprotein levels, which was more overt with the ZA/CA combination. CONCLUSION • Results from our study increase the translational potential of our in vitro fi ndings 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. © 2012 B J U I N T E R N A T I O N A L.Item Effects of exercise on angiogenesis and apoptosis-related molecules, quality of life, fatigue and depression in breast cancer patients(2013) 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. © 2013 John Wiley & Sons Ltd.Item A diverse induction of apoptosis by trabectedin in MCF-7 (HER2-/ER+) and MDA-MB-453 (HER2+/ER-) breast cancer cells(Elsevier Ireland Ltd, 2013) Atmaca H.; Bozkurt E.; Uzunoglu S.; Uslu R.; Karaca B.Trabectedin (Yondelis, ET-743), a semi synthetic tetrahydroisoquinoline alkaloid that was originally derived from the marine tunicate Ecteinascidia turbinata. The objective of this study was to investigate whether trabectedin mediated apoptosis shows any diversity in human breast cancer cell lines with different genotypes. Trabectedin induced cytotoxicity and apoptosis in both breast cancer cells in a time and concentration-dependent manner. The expression levels of the death receptor pathway molecules, TRAIL-R1/DR4, TRAIL-R2/DR5, FAS/TNFRSF6, TNF RI/TNFRSF1A, and FADD were significantly increased by 2.6-, 3.1-, 1.7-, 11.2- and 4.0-fold by trabectedin treatment in MCF-7 cells. However, in MDA-MB-453 cells, the mitochondrial pathway related pro-apoptotic proteins Bax, Bad, Cytochrome c, Smac/DIABLO, and Cleaved Caspase-3 expressions were induced by 4.2-, 3.6-, 4.8-, 4.5-, and 4.4-fold, and the expression levels of anti-apoptotic proteins Bcl-2 and Bcl-XL were reduced by 4.8- and 5.2-fold in MDA-MB-453 cells. Moreover, trabectedin treatment increased the generation of ROS in both breast cancer cells. We have shown that trabectedin causes selective activation of extrinsic and intrinsic apoptotic pathways in two genotypically different breast cancer cells. This preliminary data might guide clinicians to choose appropriate combination agents with trabectedin based on different molecular subtypes of breast cancer. © 2013 Elsevier Ireland Ltd.Item Combination of AT-101/cisplatin overcomes chemoresistance by inducing apoptosis and modulating epigenetics in human ovarian cancer cells(2013) Karaca B.; Atmaca H.; Bozkurt E.; Kisim A.; Uzunoglu S.; Karabulut B.; Sezgin C.; Sanli U.A.; 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. © 2012 Springer Science+Business Media Dordrecht.Item Enhanced cytotoxicity and apoptosis by thymoquinone in combination with zoledronic acid in hormone- and drugresistant prostate cancer cell lines(Zerbinis Publications, 2014) Dirican A.; Erten C.; Atmaca H.; Bozkurt E.; Kucukzeybek Y.; Varol U.; Tarhan M.O.; Karaca B.; Uslu R.Purpose: Thymoquinone (TQ), an active ingredient of black seed oil (Nigella Sativa), has been shown to possess cytotoxic activity against a variety of cancer cell lines. Our purpose was to investigate if the cytotoxic and apoptotic effect of zoledronic acid (ZA) can be enhanced by the addition of the TQ in hormone- and drug-refractory prostate cancer cells PC-3 and DU-145. Methods: XTT cell proliferation assay was used to assess cytotoxicity; DNA fragmentation and caspase 3/7 activity were also measured. Results: The combination of TQ and ZA resulted in a significant synergistic cytotoxic activity and DN A fragmentation when compared to any single agent alone, in a dose- and time-dependent manner. In addition, TQ and ZA combination increased the caspase 3/7 activity in PC-3 cell line, while this activity could not be demonstrated in DU-145 cell line. Conclusion: TQ and ZA had minimal hematological and non-hematological toxicity profile compared to cytotoxic agents. So, this combination may be an alternative approach for patients who are unable to be treated by conventional treatments because of poor performance status.Item Novel combination of docetaxel and thymoquinone induces synergistic cytotoxicity and apoptosis in DU-145 human prostate cancer cells by modulating PI3K–AKT pathway(Springer-Verlag Italia s.r.l., 2015) Dirican A.; Atmaca H.; Bozkurt E.; Erten C.; Karaca B.; Uslu R.Background: The treatment of castrate-resistant prostate cancer (CRPC) still remains as an important challenge of daily oncology practice. Docetaxel significantly prolongs overall survival in men with CRPC. Thymoquinone (TQ), one of the flavonoid compounds isolated from Nigealla sativa, has been shown to possess cytotoxic activity against a variety of cancer cell lines. Materials and Methods: The aim of the study was to investigate the possible synergistic cytotoxic/apoptotic effects of a novel combination, docetaxel and TQ in DU-145 hormone- and drug-refractory prostate cancer cells and their effects on PI3K and ERK signaling pathways Results: We observed that the combination of docetaxel and TQ resulted in a significant synergistic cytotoxicy and apoptosis as compared to any single agent alone, in a dose-dependent manner. It was found that viability of the combination treated cells was not significantly changed in the presence of LY294002 as compared to inhibitor treated cells. However, in the presence of FR180204, viability of combination treated cells was significantly decreased as compared to inhibitor treated cells. In conclusion, cytotoxic effect of the docetaxel and TQ combination is correlated with the block of the PI3K/Akt signaling pathway in DU-145 cells. Conclusion: Therefore, this combination strategy may be an alternative approach for the challenging era of daily oncologic practice. Also, the combination of docetaxel and TQ might allow a reduction in docetaxel doses and diminish adverse effects of docetaxel while maintaining the therapeutic effect in patients with CRPC. © 2014, Federación de Sociedades Españolas de Oncología (FESEO).