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Öğe Cytotoxic and Genotoxic Assessment of Silicon Dioxide Nanoparticles by Allium and Comet Tests(Springer, 2020) Liman, Recep; Acikbas, Yaser; Cigerci, Ibrahim Hakki; Ali, Muhammad Muddassir; Kars, Meltem DemirelSilicon nanoparticles gained a great interest due to its use in biomedical research. It is considered as safe and has been used in nanomedicine. But literature still states its toxicity depending upon the size and dose of silicon nanoparticles. So, current study was aimed to evaluate the cytotoxicity and genotoxicity of silicon dioxide nanoparticles -(SiO(2)NPs) by Allium anaphase-telophase and Comet tests. Characterization of -SiO(2)NPs showed the particle size as 16.12 +/- 3.07 nm. The mean diameter of -SiO(2)NPs was having range of 404.66 +/- 93.39 nm in solution. Highest total anomalies ( 18.80 +/- 0.45) were observed at 100 mu g/mL, whereas least (11.2 +/- 0.84) were observed by the 12.5 mu g/mL concentration. There was concentration-response association in increased CAs and DNA damage. The highest concentration (100 mu g/mL) of -SiO(2)NPs induced the significant DNA damage (149.67 +/- 1.15), whereas the least was observed by the negative control (2.67 +/- 0.58). The current study revealed the cytotoxic and genotoxic effects of -SiO(2)NPs on the root meristem cells of A. cepa.Öğe Determination of the target proteins in chemotherapy resistant breast cancer stem cell-like cells by protein array(Elsevier Science Bv, 2019) Kars, Meltem Demirel; Yildirim, GamzeBreast cancer comes second among the causes of cancer deaths of women. Although new generation hormone therapy is a promising strategy, re-occurrence or emergence of drug resistance limits the success. According to the theory of cancer stem cells (CSCs); CSCs are immortal, tumor inducing and self renewing pluripotent cells and multiply as chemotherapy proceeds, making the chemotherapy inefficient. Emerging scientific reports indicate that the mechanisms of drug resistance are the main features that CSCs gain actually. Due to this fact, cancer stem cell markers should be clarified to target CSCs and this will play important role to reverse drug resistance. In this study, MCF-7 /Pac, a cell line resistant to microtubule inhibitor paclitaxel and multiple drugs permanently, was used as a reference cell line for drug resistant mammary cancer. It has some properties that breast cancer stem cells possess so it is considerable to isolate breast cancer stem cell-like cells from MCF-7 /Pac population. The chemotherapy resistant breast cancer stem-like (BCSC-like) cells were sorted from MCF-7 /Pac population by using markers CD44, CD24 and ALDH. At the next step the proteins that are up-regulated in BCSC-like cells were determined by protein array analysis. Additionally the effect of paclitaxel on BCSC-like cell proliferation was determined. The MCF-7 /Pac population contains 12.4% BCSC-like cells. The cells bearing BCSC-like cell phenotype exhibited resistance to paclitaxel. The over-expressed growth factors, MMP proteins, Frizzled proteins and IL-23 were found to be related to the BCSC-like cell proliferation. These results will guide both basic science and medical science.Öğe DRUG RESISTANCE RESTRICTS THE EFFICACY OF SHORT TERM LOW DOSE MITOMYCIN-C TREATMENT IN UMUC-3 BLADDER CANCER CELLS(Iniestares, S.A., 2018) Gul, Murat; Goktas, Serdar; Kars, Meltem Demirel; Kaynar, MehmetOBJECTIVE: Mitomycin-c (MMC) is the most used intravesical adjuvant agent in non-muscle invasive bladder cancer to prevent recurrence. However, a consensus on about appropriate dosage and treatment schedule of MMC is lacking. We, therefore, aimed to evaluate the most appropriate MMC dosage using an in vitro model of high-grade human bladder cancer. METHODS: UMUC-3 cells, a model for high-grade bladder cancer, were exposed to MMC in different time courses to assess its toxicological effects. XTT cell proliferation kit was used to evaluate the effect of MMC on the proliferation of UMUC-3 cell line. Gene expression analysis for the MDR1, BCL2 and ANXA5 genes was performed by Real-time PCR and flow cytometry analysis were conducted to evaluate the cell death mechanism and acquired resistance after MMC exposure. An ANXA5 kit was used to detect apoptotic cells, and 7-AAD was used to detect necrotic cells. RESULTS: Cell proliferation was prevented to a large extent (IC50, 0.175-0.081 mg/mL) and cytotoxic effects were observed after 5 mu g/mL and 10 mu g/mL MMC administrations for 1 and 2-h, after the 4th and 2nd dose cycles, respectively. Moreover, cell death was observed at 5 mu g/mL and 10 mu/mL MMC applications for 1-h and 2-h by the sixth and second week, respectively. Flow cytometry exhibits increased subpopulation of drug-extruding UMUC-3 cells after a single dose of MMC for 1-h. MMC did not increase the number of apoptotic or necrotic cells; yet, MDR1 (multiple drug resistance) and ANXA5 (apoptotic) expression levels were increased and BCL2 (anti-apoptotic) expression was decreased. Limitations: In-vitro nature of the study and working with only one cell culture are inherit limitations of this project. CONCLUSION: A single dose of MMC administration for 1 or 2-h results in drug-resistance. If maintenance treatment is administered for one hour, it should be continued throughout a 6-week period.Öğe The effects of trastuzumab, paclitaxel, and carboplatin on HER2-positive cancer stem cells that are isolated from primary breast cancer cultures: a preliminary report(Amer Assoc Cancer Research, 2015) Artac, Mehmet; Kayadibi, Gozde; Ceylan, Ayca; Kars, Meltem Demirel; Artac, Hasibe; Cakir, Murat; Boruban, Cem[Abstract Not Availabe]Öğe Enhancement of PCL/PLA Electrospun Nanocomposite Fibers Comprising Silver Nanoparticles Encapsulated with Thymus Vulgaris L. Molecules for Antibacterial and Anticancer Activities(Amer Chemical Soc, 2022) Cimen, Cansu Gunes; Dundar, Mehmet Akif; Kars, Meltem Demirel; Avci, AhmetSilver nanoparticles (AgNPs) have been recognized for their outstanding antibacterial activities, which are required for antibacterial coating materials in therapeutic applications. A bacterial resistant electrospun nanofibrous mat made of polycaprolactone (PCL) in combination with polylactide acid (PLA) containing silver nanoparticles encapsulated with Thymus vulgaris L. (thyme) extract (eAgNPs) was fabricated in order to assess the potential of applicability in biomedical applications such as cancer treatment, wound healing, or surgical sutures. In the current study, PCL and PLA used as the basis polymers were blended with biosynthesized eAgNPs, pure AgNPs, and thyme extract (TE) to observe the effects of additives in terms of antibacterial and anticancer activity and morphologic, thermal, mechanical, biocompatibility, and biodegradability properties. The biological characteristics of fabricated electrospun nanofibrous mats were evaluated in vitro. Physicochemical characteristics of the nanofibrous mats were examined by UV-vis spectrophotometry, scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), mechanical tensile testing, X-ray diffraction (XRD), thermogravimetric examination (TGA), and water contact angles (WCAs). The results showed that a biodegradable nanofiber scaffold with a mean fiber diameter of 280 nm is morphologically homogeneous and highly hydrophobic, has higher tensile strength than PCL/PLA nanocomposite fiber, and is resistant to Escherichia coli and Staphylococcus aureus. The cytotoxic and anticancer properties of nanomaterials were defined using L929 and SK-MEL-30 cells. The developed material inhibited cell proliferation and led to apoptosis of cell lines. It can be suggested that the use of Thymus vulgaris L. extract-encapsulated silver nanoparticle-doped PCL/PLA nanofibers produced by the electrospinning method has the potential for cancer therapy in skin tumor cell lines.Öğe In vitro assessment of Momordica charantia/Hypericum perforatum oils loaded PCL/Collagen fibers: Novel scaffold for tissue engineering(Sage Publications Ltd, 2024) Ediz, Emre Fatih; Gunes, Cansu; Kars, Meltem Demirel; Avci, AhmetThe research on tissue engineering applications has been progressing to manufacture ideal tissue scaffold biomaterials. In this study, a double-layered electrospun biofiber scaffold biomaterial including Polycaprolactone (PCL)/Collagen (COL) fibrous inner layer and PCL/ Momordica charantia (MC) and Hypericum perforatum (HP) oils fibrous outer layer was developed to manufacture a functional, novel tissue scaffold with the advantageous mechanical and biological properties. The main approach was to combine the natural perspective using medicinal oils with an engineering point of view to fabricate a potential functional scaffold for tissue engineering. Medicinal plants MC and HP are rich in functional oils and incorporation of them in a tissue scaffold will unveil their potential to augment both new tissue formation and wound healing. In this study, a novel double-layered scaffold prototype was fabricated using electrospinning technique with two PCL fiber layers, first is composed of collagen, and second is composed of oils extracted from medicinal plants. Initially, the composition of plant oils was analyzed. Thereafter the biofiber scaffold layers were fabricated and were evaluated in terms of morphology, physicochemistry, thermal and mechanical features, wettability, in vitro bio-degradability. Double-layered scaffold prototype was further analyzed in terms of in vitro biocompatibility and antibacterial effect. The medicinal oils blend provided antioxidant and antibacterial properties to the novel PCL/Oils layer. The results signify that inner PCL/COL layer exhibited advanced biodegradability of 8.5% compared to PCL and enhanced wettability with 11.7(degrees) contact angle. Strength of scaffold prototype was 5.98 N/mm(2) thanks to the elastic PCL fibrous matrix. The double-layered functional biofiber scaffold enabled 92% viability after 72 h contact with fibroblast cells and furthermore provided feasible attachment sites for the cells. The functional scaffold prototype's noteworthy mechanical, chemical, and biological features enable it to be suggested as a different novel biomaterial with the potential to be utilized in tissue engineering applications.Öğe Response to trastuzumab and investigation of expression profiles of matrix metalloproteinase-related proteins in primary breast cancer stem cells(Springer-Verlag Italia Srl, 2021) Koygun, Gozde Kayadibi; Kars, Meltem Demirel; Emsen, Ayca; Artac, Hasibe; Aksoy, Faruk; Cakir, Murat; Tavli, LemaBreast cancer (BC) is the leading cause of cancer deaths in women. One of the reasons for the failure of BC treatment is reportedly the ineffectiveness of chemotherapeutic drugs against breast cancer stem-like cells (BCSCs). HER2 receptors have an important role in the self-renewal of BCSCs. Matrix metalloproteinase (MMP) and cytokine levels were found to be higher in BCSCs, which demonstrates their potential metastatic capacity. Therefore, the aim of this study was to evaluate the response of BCSCs to trastuzumab and to investigate the MMP levels in primary breast cancer cells and HER2(+) BCSCs. Tumour tissue samples were obtained during surgical intervention from ten breast cancer patients, and primary culture cells were established from these tissues. Four major molecular subgroups were sorted from the primary culture: HER2(+) BCSCs (CD44(+)CD24(-)HER2(+)), HER2(-) BCSCs (CD44(+)CD24(-)HER2(-)), HER2(-) primary culture cells (CD44(+)CD24(+)HER2(-)) and triple positive primary culture cells (CD44(+)CD24(+)HER2(+)). These cells were cultured and treated with trastuzumab, paclitaxel, carboplatin, and the combination of those three drugs for 96 h. Cellular responses to these drugs were determined by XTT cytotoxicity test. MMPs and cytokine array analysis showed that MMPs and TIMP-1, TIMP-2 proteins were expressed more in HER2(+) BCSCs than in primary culture. HER2(-) BCSCs were more resistant to drugs than HER2(+) BCSCs. Our findings suggest that the presence of HER2(-) BCSCs may be responsible for primary trastuzumab resistance in HER2(+) BC cell population. Further studies investigating the function of MMPs are needed for drug targeting of BCSCs.
