Browsing by Author "Uzunoglu S."
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Item Augmentation of methylprednisolone-induced differentiation of myeloid leukemia cells by serine/threonine protein phosphatase inhibitors(1999) Uzunoglu S.; Uslu R.; Tobu M.; Saydam G.; Terzioglu E.; Buyukkececi F.; Omay S.B.To elucidate the roles of serine/threonine protein phosphatases type 1 (PP1) and type 2A (PP2A) in methylprednisolone-induced differentiation of HL60 cells into granulocytes and K562 cells into monocytes, we examined the effect of serine/threonine protein phosphatase inhibitors, okadaic acid and Cal-A on the proliferation/differentiation of HL60 and K562 cells. Okadaic acid and Cal-A augmented methylprednisolone induced granulocytic differentiation and cell death of HL60 cells and monocytic differentiation and cell death of K562 cells in different dose ranges, respectively. These data suggest an important role of PP1 and PP2A in the mechanism leading to differentiation of leukemic cells.Item Up-regulation of serine/threonine protein phosphatase type 2A regulatory subunits during methylprednisolone-induced differentiation of leukaemic HL-60 cells(2000) Aydin H.H.; Selvi N.; Saydam G.; Tobu M.; Uzunoglu S.; Uslu R.; Buyukkececi F.; Omay S.B.Serine/threonine protein phosphatase 2A (PP2A) may play a role in leukaemic cell differentiation of the HL 60 myeloid leukaemic cell-line after methylprednisolone induction. We have investigated the specific enzyme activity and expression of catalytic and regulatory subunits of PP2A. The resulting specific enzyme activity and immunoblots showed an increase in enzyme activity and the expression of regulatory subunits after methylprednisolone treatment. There was no change in the expression of PP2A catalytic subunits. It is suggested that the effect of methylprednisolone on leukaemic differentiation may be the result of PP2 A upregulation.Item Zoledronic acid effects interleukin-6 expression in hormone-independent prostate cancer cell lines(Brazilian Society of Urology, 2008) Asbagh L.A.; Uzunoglu S.; Cal C.Objective: To investigate the inhibitory effects of zoledronic acid (ZA) on tumor related growth factor IL-6 in hormone resistant prostate cancer cell lines. The association between apoptosis and IL-6 inhibition was also assessed. Materials and Methods: PC-3 and DU145 cell lines were treated with different concentrations of ZA (1-100μM) at various intervals (24-72 h.). The cell viability was investigated by XTT assay and apoptotic effect was evaluated by cell death detection ELISA kit. Caspase 3/7 activity assay was performed to confirm apoptosis. IL-6 levels were measured by ELISA in the supernatant, and these data were also confirmed by IL-6 mRNA analysis using RT-PCR. Results: PC-3 and DU145 cell lines were sensitive to ZA mediated cytotoxicity in a dose- and time-dependent manner. However, the apoptotic effect was significantly different among PC-3 and DU145 cells (p < 0.05). IL-6 secretion was significantly lower in both cell lines, compared to the untreated control cells (p < 0.05). Although the increased inhibition of IL-6 secretion was associated with increased apoptosis in DU145 cells (p = 0.002), there was no similar association for PC-3 cell line (p = 0.347). When compared to the untreated controls, the number of cDNA copies was significantly lower in the ZA treated DU145 cell line at doses of 30 and 90μM (p < 0.05), suggesting a reduced expression of IL-6 mRNA. Conclusion: ZA exhibited a time- and dose-dependent apoptotic effect on PC-3,and DU145 prostate cancer cell lines and this effect was associated with inhibited secretion of IL-6 in DU145 cell line.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 Results of factorial validity and reliability of the international outcome inventory for hearing aids in Turkish(2009) Serbetcioglu B.; Mutlu B.; Kirkim G.; Uzunoglu S.Objective; The International Outcome Inventory for Hearing Aids (IOI-HA) with seven-item questionnaire is used to evaluate the effectiveness of audiological rehabilitation programme utilizing hearing aids. Factor analysis of the subscales of the IOI-HA has been previously reported for English and Dutch translations, but not for the Turkish Language. Thus, the main objective of this study was to evaluate the internal consistency and factorial (construct) validity of the IOI-HA that was translated to Turkish. Materials & Methods; Participants were 45 hearing impaired adults (23 male, 22 female) who were included in audiological rehabilitation programme between January 2006 and June 2007. The study was performed in tertiary referral center, Dokuz Eylül University, Medical School, Department of Otolaryngology. The mean age of subjects was 64.15 ± 13.8 years. Average pure-tone thresholds at frequencies of 0.5, 1 and 2 kHz (PTA1) of the aided ear were ranged from 33 dB HL to 78 dB HL with a mean of 51.7 * 10.1 dB HL. Mean speech discrimination score was 70.2%±18.08. Forty-five adult patients were evaluated by using IOI-HA as a part of the audiological rehabilitation programme. Results; The factor analysis yielded strong support for a unifactorial structure of the scale, and a high internal consistency of the inventory (p<0.05) (Cronbach's alpha value were found to be 0.773 at first month and 0.783 at sixth month). It is interpreted that the IOI-HA translated to Turkish has enough reliability and factorial validity. Conclusion; This version can be used in the evaluation of the hearing aid satisfaction in Turkish hearing impaired population. Copyright 2005 © The Mediterranean Society of Otology and Audiology.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 Apoptosis-mediated cytotoxic effects of ibandronic acid on hormone-and drug-refractory prostate cancer cells and human breast cancer cells(SAGE Publications Ltd, 2010) Kucukzeybek Y.; Gorumlu G.; Cengiz E.; Karabulut B.; Sezgin C.; Atmaca H.; Sanli U.A.; Uzunoglu S.; Uslu R.Over 80% of patients with advanced breast and prostate cancer ultimately develop bone metastases. Ibandronic acid has proven efficacy for treatment of bone metastasis secondary to breast cancer. This study was designed to investigate the cytotoxic and apoptotic effects of ibandronic acid on hormone- and drug refractory prostate carcinoma DU-145 and human breast cancer MCF-7 cell lines. Cytotoxicity was evaluated using an XTT cell proliferation kit, and apoptosis was assessed by enzyme-linked immuno sorbent assay (histone-DNA fragmentation) and measurement of caspase 3/7 activity. With increasing concentrations of ibandronic acid there was a dose- and time-dependent decrease in cell numbers. MCF-7 cells were more resistant than DU-145 cells (half maximal inhibitory concentrations of 122 and 90 μM, respectively). Ibandronic acid induced apoptosis in both cell lines. The study showed an apoptosis-mediated cytotoxic effect for ibandronic acid (in addition to the already known osteoclast inhibiting effect) in breast cancer patients with bone metastases; which was also observed in prostate cancer cells. Further clinical studies involving breast and prostate cancer patients with bone metastases are warranted to confirm these findings. © 2010 Field House Publishing LLP.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.