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ÖZBAŞ, SUNA

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ÖZBAŞ

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2015 - 201912020 - 20232
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    PublicationOpen Access
    A new gene therapy approach by tenascin-c genome editing induces apoptosis and cell cycle arrest in triple- negative breast cancer cells
    (2023-02-01) ÖZBAŞ, SUNA; Bareke H., ŞALVA E., ÖZBAŞ S.
    BACKGROUND/AIMS: There is a pressing need for new therapies for the most aggressive subtype of breast cancer, triple-negative breast cancer (TNBC). Tenascin-C (TN-C) codes for a tumor microenvironment-specific protein, which promotes apoptosis evasion and cell proliferation. The aim of this study was to knock down TN-C by using the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system to induce cancer cell apoptosis and stunt cell proliferation, laying the grounds for a new gene therapy approach in TNBC.MATERIALS and METHODS: The human TNBC cell line, MDA-MB-231 cells were transfected by TN-C-specific CRISPR/Cas9 plasmids. TN-C messenger RNA levels were assessed by real-time polymerase chain reaction to determine the knock-down efficiency. Two days after the transfection, the percentage of apoptotic cells and the proportion of cells in cell cycle phases were compared between the treatment and the control groups using flow cytometry. The resultant change in cell proliferation due to the knock-down was determined by MTT assay. RESULTS: Transfection with the TN-C CRISPR/Cas9 plasmid reduced TN-C levels in the cells by approximately 49% relative to the scrambled -control CRISPR/Cas9 transfected cells. This TN-C downregulation increased the percentage of cells in apoptosis and induced G1-phase arrest. The combined effect of apoptosis and cell cycle arrest led to a significant decrease in the number of cancer cells in the treatment group.CONCLUSION: Our successful preliminary study of a potential TNBC gene therapy based on TN-C genome editing by the CRISPR/Cas9 system led to significant decrease in TNBC cell numbers and it justifies the testing of this system in more advanced preclinical studies.
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    PublicationOpen Access
    Differences between Solution and Membrane Forms of Chitosan on the In Vitro Activity of Fibroblasts
    (GALENOS YAYINCILIK, 2015-02-16) ÖZBAŞ, SUNA; Uslu, Bahar; Biltekin, Burcu; Denir, Secnur; Ozbas-Turan, Suna; Arbak, Serap; Akbuga, Julide; Bilir, Ayhan
    Background: Chitosan, a linear polysaccharide, has been recently used in biomedical applications. In vitro studies have demonstrated its effect on cellular growth and its stimulatory action on cellular layer formation. Aims: The present study aims to compare the proliferative effects of chitosan in two forms, membranous and solution forms, on Swiss 3T3 mouse embryonic fibroblasts. Study Design: In vitro study. Methods: Three experimental groups were formed: cells were cultured in a normal medium without chitosan (Control Group); cells were cultured either in a medium containing 2.0% chitosan in membranous form (Membrane Group) or chitosan solution at a concentration of 2.0% (Solution Group). Two different methods were used in the experiments: cells cultured on the medium containing chitosan in solution or membranous forms (method 1); and chitosan solution or membranous forms were added into the medium containing previously cultured cells (method 2). Results: Scanning electron microscopic investigations of the experimental groups revealed cells with well-defined cellular projections, intact cellular membranes and tight intercellular junctions. They were especially prominent in the membrane group of method 1 and in the membrane and solution groups of method 2. Mouse monoclonal anti-collagen 1 primary antibody was used to indicate collagen synthesis. Prominent collagen synthesis was detected in the membrane groups on the 10th day of culture for both methods. Bromodeoxyuridine (BrdU) and MTT assays were performed in order to assess cellular proliferation and viability, respectively. BrdU labelling tests indicated a higher proliferation index in the membrane group of method 1 on the 5th and 10th days. For the second method, the membranous form on the 10th day and solution form on the 5th day were the most effective groups in terms of cellular proliferation. MTT results reflected a high cellular viability in method 1 on the 5th day of treatment with the membranous form, whereas cellular viability was highest in the solution form of method 2 on the 5th day. Conclusion: The membranous form of chitosan induced a significant proliferative effect and increased the ratio of cell-to-cell junctions of Swiss 3T3 mouse embryonic fibroblasts. Conveniently, the solution form also resulted in enhanced cell proliferation and viability compared to the control group. As the solution form is easy to prepare and apply to cells compared to the membrane form, the application of Chitosan directly to media appears to be a convenient alternative for tissue engineering approaches.
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    PublicationOpen Access
    Investigation of therapeutic effects in the wound healing of chitosan/pGM-CSF complexes
    (2022-01-01) ÖZBAŞ, SUNA; ŞALVA E., ALAN S., Karakoyun B., Cakalagaoglu F., ÖZBAŞ S., Akbuga J.
    Granulocyte macrophage colony-stimulating factor (GM-CSF) has been shown to promote the growth, proliferation, and migration of endothelial and keratinocyte cells. Chitosan has been widely used as a biopolymer in wound-healing studies. The aim of this study was to investigate the in vitro proliferative effects of chitosan/pGM-CSF complexes as well as the therapeutic role of the complexes in an in vivo rat wound model. The effect of complexes on cell proliferation and migration was examined. Wounds were made in Wistar-albino rats, and examined histopathologically. The cell proliferation and migration were increased weight ratio- and time-dependently in HaCaT and NIH-3T3 cell lines. Wound healing was significantly accelerated in rats treated with the complexes. These results showed that the delivery of pGM-CSF using chitosan complexes could play an accelerating role in the cell proliferation, migration, and wound-healing process.