Person: ÖZBAŞ, SUNA
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ÖZBAŞ
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SUNA
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Publication Open Access Generation of stable cell line by using chitosan as gene delivery system(SPRINGER, 2016-08) EKENTOK ATICI, CEYDA; Salva, Emine; Turan, Suna Ozbas; Ekentok, Ceyda; Akbuga, JulideEstablishing stable cell lines are useful tools to study the function of various genes and silence or induce the expression of a gene of interest. Nonviral gene transfer is generally preferred to generate stable cell lines in the manufacturing of recombinant proteins. In this study, we aimed to establish stable recombinant HEK-293 cell lines by transfection of chitosan complexes preparing with pDNA which contain LacZ and GFP genes. Chitosan which is a cationic polymer was used as gene delivery system. Stable HEK-293 cell lines were established by transfection of cells with complexes which were prepared with chitosan and pVitro-2 plasmid vector that contains neomycin drug resistance gene, beta gal and GFP genes. The transfection efficiency was shown with GFP expression in the cells using fluorescence microscopy. Beta gal protein expression in stable cells was examined by beta-galactosidase assay as enzymatically and X-gal staining method as histochemically. Full complexation was shown in the above of 1/1 ratio in the chitosan/pDNA complexes. The highest beta-galactosidase activity was obtained with transfection of chitosan complexes. Beta gal gene expression was 15.17 ng/ml in the stable cells generated by chitosan complexes. In addition, intensive blue color was observed depending on beta gal protein expression in the stable cell line with X-gal staining. We established a stable HEK-293 cell line that can be used for recombinant protein production or gene expression studies by transfecting the gene of interest.Publication Open Access Plasmid DNA-loaded chitosan/TPP nanoparticles for topical gene delivery(INFORMA HEALTHCARE, 2011-04) ÖZBAŞ, SUNA; Ozbas-Turan, Suna; Akbuga, JulideTopical application of plasmid DNA represents an attractive route of gene delivery. Although chitosan (CS) has been widely investigated as a gene-carrier, there is very limited information about the skin application of CS-based systems for DNA. This study evaluated pDNA-loaded chitosan nanoparticles (CS-NPs) for skin gene delivery. NPs were prepared by inducing the gelation of CS upon interaction with sodium tripolyphosphate. pSV-beta-Gal was used as a reporter gene. The size, surface charge, and the other in vitro characteristics of CS-NPs were examined. Primary human dermal fibroblast cells (HDF) and mouse fibroblast NIH 3T3 cell lines (ATCC CCL-92) were used for in vitro transfection studies. In in vivo study, CS-NPs were applied to the skin of baby and adult Sprague Dawley rats by spreading on the shaved area of the back of animals. During a week animals were sacrificed and skin biopsies were taken for beta-Gal expression. beta-galactosidase enzyme activity was determined spectrophotometrically at 420 nm. The distribution of beta-galactosidase expressing cells within the skin tissue was observed by X-gal histochemical method. beta-galactosidase was continuously expressed at the nanoparticle-treated skin during the 7 days. High and continuous beta-Gal expressions were obtained with CS-NPs, although it was low in the first day. When a comparison was made between the data of baby and adult rats, markedly high transfection were measured in the skin samples of the baby rats. NPs protected pDNA against the enzyme and serum attacks. In conclusion, CS-NPs showed in vivo transfection potential in rats for skin gene delivery.Publication Open Access In vitro gene silencing effect of chitosan/shRNA PDGF-D nanoparticles in breast cancer(MARMARA UNIV, FAC PHARMACY, 2017-10-03) EKENTOK ATICI, CEYDA; Ekentok, Ceyda; Turan, Suna Ozbas; Akbuga, JulideBreast cancer is the most common cancer worldwide in women and it is highly malignant and fatal. PDGF-D plays role in regulation of many cellular processes such as angiogenesis. PDGF-D is overexpressed in many types of cancers and promote tumor growth and metastasis. Silencing of PDGF-D gene by using shRNA with an appropriate carrier system may decrease tumor growth and metastasis. In our study, we prepared chitosan nanoparticles loaded with five different shRNA plasmids targeting different exons of PDGF-D gene. Then, nanoparticles were characterized in vitro and transfection efficiency of these nanoparticles were investigated in breast cancer cell lines (MCF7, MDA-MB-231 and MDA-MB-435). The effects of single and multiple shRNA sequences, molecular weight of chitosan (150 kDa and 400 kDa) and the amount of shRNA (100 and 500 mu g) on the characterization and transfection efficiencies of nanoparticles have been studied. Size of nanoparticles changed between 200-400 nm and approximately 95-100% encapsulation efficiency were obtained. Release of shRNA changed with the molecular weight of chitosan. It was obtained that formulation containing shRNA plasmid targeting PDGF-D exon 6 (NP1) has the highest silencing efficiency in MDA-MB-231 cell line. It was also evaluated that chitosan can be a suitable gene delivery system for shRNA targeting PDGF-D.Publication Metadata only Comparison of VEGF gene silencing efficiencies of chitosan and protamine complexes containing shRNA(WILEY, 2014) ÖZBAŞ, SUNA; Erdem-Cakmak, Fulden; Ozbas-Turan, Suna; Salva, Emine; Akbuga, JulideVEGF is an angiogenic factor promoting the proliferation and migration of endothelial cells. Inhibition of VEGF by RNAi mechanism is one of the novel and the most important strategies in antiangiogenesis therapy. In this study, the tumor silencing efficiency of ternary complexes after addition of protamine to chitosan complexes containing VEGF targeting shRNA was investigated. Besides chitosan, protamine is an effective gene delivery material. Binary and ternary complexes consisting of chitosan, protamine, and shRNA were prepared to target VEGF, their morphology, size, and zeta potential of the complexes being measured. The average size of the complexes was between 173 and 284nm and zeta potential was between +10 and 16mV. In the ternary complexes, size decreased as the chitosan ratio increased; however, its molecular weight had no effect on the size of complexes. HeLa, HEK293, and MCF-7 cell lines were used for in vitro transfection. VEGF was assayed by ELISA. A higher silencing effect was obtained using ternary complexes. Transgene expression was increased by adding protamine to chitosan complexes. Gene inhibition values in cell lines followed the rank HEK293>HeLa>MCF-7. The addition of protamine to the chitosan/shRNA (VEGF) complexes increased the knockdown of VEGF genes in the cell lines, and no cytotoxicity was found after the complexes had been incorporated into the cells.Publication Metadata only Evaluation of antisense oligonucleotide loaded chitosan nanoparticles; characterization and antisense effect(GOVI-VERLAG PHARMAZEUTISCHER VERLAG GMBH, 2009) ÖZBAŞ, SUNA; Ozbas-Turan, S.; Akbuga, J.; Enneli, B.The objective of this study was to investigate the effect of different formulation parameters [i.e. molecular weight and concentration of chitosan, concentration of tripolyphosphate (TPP) and use of alginate] on physico chemical and antisense properties of antisense oligonucleotide (AsODN) loaded chitosan nanoparticles (NPs). Preparation methods of phosphodiester (PO) and phosphorothioate (PS) AsODNs-NPs were also compared. AsODNI was designed to target the beta-galactosidase (beta-gal) gene. HeLa cells were used for in vitro transfection studies and beta-gal was assayed spectrophotometrically. AsODN-NPs obtained were in general positively charged with size between 221.4-525.7 nm depending on formulation. Encapsulation efficiency of NPs depended on the type of backbone of the AsODN. PO-AsODN encapsulation into NPs (78-94%) was less efficient than PS encapsulation (91-98%). The pH of the chitosan solution affected AsODN entrapment. PO-NPs exhibited faster AsODN release than NPs containing PS. In general higher beta-gal inhibition was obtained after transfection of AsODN-NPs in cell culture studies. PS-NPs exhibited a higher inhibition effect and the highest (90.71%) inhibition was obtained with formulation PT-2. PS-adsorbed NPs showed an 88% reduction in beta-gal. This study can form the basis for forthcoming in vivo studies related to AsODN carrier systems that will use chitosan.Publication Metadata only Topical Application of Antisense Oligonucleotide-Loaded Chitosan Nanoparticles to Rats(MARY ANN LIEBERT INC, 2010) SEZER, ALİ DEMİR; Ozbas-Turan, Suna; Akbuga, Juelide; Sezer, Ali DemirSkin delivery of antisense oligonucleotides (AsODNs) has exciting potential in the treatment of skin diseases. However, the therapeutic applications of oligonucleotide-based therapies are limited by the instability of these molecules toward nucleases, short half-life in vivo, and insufficient cellular uptake. The purpose of this study was to investigate in vivo antisense effect of AsODN-loaded chitosan nanoparticles after topical application. AsODN-loaded chitosan nanoparticles were topically applied to Sprague Dawley rats (adult and baby). At 1, 3, 6, 9, and 12 days posttransfection, animals' skin samples were taken for measurement of beta-galactosidase (beta-Gal) expression and histological control. After topical application of AsODN-loaded chitosan nanoparticles in different doses, beta-Gal expression reduced significantly. Highest inhibition was observed after 6 days of transfection of nanoparticles. Free AsODNs exhibited 35% of beta-Gal inhibition on the first day. beta-Gal expression was inhibited in approximately 82-85% with transfection of nanoparticles containing 30 mg AsODNs at 6 days. The antisense effect of AsODN-loaded chitosan nanoparticle in baby skin was evaluated at 6 days: 77-86% of beta-Gal suppression was measured and differences between the doses were not significant. Thus, chitosan nanoparticles are useful carrier for delivery of AsODNs into skin cells of rats and may be used for topical application on human skin.Publication Metadata only Spectrophotometric, voltammetric and cytotoxicity studies of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone and its N(4)-substituted derivatives: A combined experimental-computational study(PERGAMON-ELSEVIER SCIENCE LTD, 2015) AKKİPRİK, MUSTAFA; Akgemci, Emine Guler; Saf, Ahmet Ozgur; Tasdemir, Halil Ugur; Turkkan, Ercan; Bingol, Haluk; Turan, Suna Ozbas; Akkiprik, MustafaIn this study, 2-hydroxy-5-methoxyacetophenone thiosemicarbazone (HMAT) and its novel N(4) substituted derivatives were synthesized and characterized by different techniques. The optical band gap of the compounds and the energy of HOMO were experimentally examined by UV-vis spectra and cyclic voltammetry measurements, respectively. Furthermore, the conformational spaces of the compounds were scanned with molecular mechanics method. The geometry optimization, HOMO and LUMO energies, the energy gap of the HOMO LUMO, dipole moment of the compounds were theoretically calculated by the density functional theory B3LY10/6-3114-+G(d,p) level. The minimal electronic excitation energy and maximum wavelength calculations of the compounds were also performed by TD-DFT//B3LYP/6-311++G(d,p) level of theory. Theoretically calculated values were compared with the related experimental values. The combined results exhibit that all compounds have good electron-donor properties which affect anti-proliferative activity. The cytotoxic effects of the compounds were also evaluated against HeLa (cervical carcinoma), MCF-7 (breast carcinoma) and PC-3 (prostatic carcinoma) cell lines using the standard MIT assay. All tested compounds showed antiproliferative effect having IC50 values in different range. In comparison with that of HMAT, it was obtained that while ethyl group on 4(N)-substituted position decreased in potent anti-proliferative effect, the phenyl group on the position increased in anti-proliferative effect for the tested cancer cell line. Considering the molecular energy parameters, the cytotoxicity activities of the compounds were discussed. (C) 2014 Elsevier B.V. All rights reserved.