PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Citation - WoS: 79Citation - Scopus: 94Biofabrication of in Situ Self Assembled 3d Cell Cultures in a Weightlessness Environment Generated Using Magnetic Levitation(Nature Publishing Group, 2018) Anıl İnevi, Müge; Yaman, Sena; Arslan Yıldız, Ahu; Meşe, Gülistan; Yalçın Özuysal, Özden; Tekin, Hüseyin Cumhur; Özçivici, EnginMagnetic levitation though negative magnetophoresis is a novel technology to simulate weightlessness and has recently found applications in material and biological sciences. Yet little is known about the ability of the magnetic levitation system to facilitate biofabrication of in situ three dimensional (3D) cellular structures. Here, we optimized a magnetic levitation though negative magnetophoresis protocol appropriate for long term levitated cell culture and developed an in situ 3D cellular assembly model with controlled cluster size and cellular pattern under simulated weightlessness. The developed strategy outlines a potential basis for the study of weightlessness on 3D living structures and with the opportunity for real-time imaging that is not possible with current ground-based simulated weightlessness techniques. The low-cost technique presented here may offer a wide range of biomedical applications in several research fields, including mechanobiology, drug discovery and developmental biology.Article Citation - WoS: 22Citation - Scopus: 25The Endocytic Pathway and Therapeutic Efficiency of Doxorubicin Conjugated Cholesterol-Derived Polymers(Royal Society of Chemistry, 2015) Sevimli, Sema; Sagnella, Sharon; Macmillan, Alexander; Whan, Renee; Kavallaris, Maria; Bulmuş, Volga; Davis, Thomas P.Previously synthesized poly(methacrylic acid-co-cholesteryl methacrylate) P(MAA-co-CMA) copolymers were examined as potential drug delivery vehicles. P(MAA-co-CMA) copolymers were fluorescently labelled and imaged in SHEP and HepG2 cells. To understand their cell internalization pathway endocytic inhibition studies were conducted. It was concluded that P(MAA-co-CMA) are taken up by the cells via clathrin-independent endocytosis (CIE) (both caveolae mediated and cholesterol dependent endocytosis) mechanisms. The formation and characterization of P(MAA-co-CMA)-doxorubicin (DOX) nanocomplexes was investigated by fluorescence lifetime imaging microscopy (FLIM), UV-Visible spectroscopy (UV-Vis) and dynamic light scattering (DLS) studies. The toxicity screening between P(MAA-co-CMA)-DOX nanocomplexes (at varying w/w ratios) and free DOX, revealed nanocomplexes to exhibit higher cytotoxicity towards cancer cells in comparison to normal cells. FLIM and confocal microscopy were employed for investigating the time-dependent release of DOX in SHEP cells and the cellular uptake profile of P(MAA-co-CMA)-DOX nanocomplexes in cancer and normal cell lines, respectively. The endocytic pathway of P(MAA-co-CMA)-DOX nanocomplexes were examined in SHEP and HepG2 cells via flow cytometry revealing the complexes to be internalized through both clathrin-dependent (CDE) and CIE mechanisms. The drug delivery profile, reported herein, illuminates the specific endocytic route and therapeutic efficiency of P(MAA-co-CMA)-DOX nanocomplexes strongly suggesting these particles to be promising candidates for in vivo applications.Article Citation - WoS: 56Citation - Scopus: 63Thioredoxin Is Required for Deoxyribonucleotide Pool Maintenance During S Phase(American Society for Biochemistry and Molecular Biology, 2006) Koç, Ahmet; Mathews, Christopher K.; Wheeler, Linda J.; Gross, Michael K.; Merrill, Gary FredericThioredoxin was initially identified by its ability to serve as an electron donor for ribonucleotide reductase in vitro. Whether it serves a similar function in vivo is unclear. In Saccharomyces cerevisiae, it was previously shown that Δtrx1 Δtrx2 mutants lacking the two genes for cytosolic thioredoxin have a slower growth rate because of a longer S phase, but the basis for S phase elongation was not identified. The hypothesis that S phase protraction was due to inefficient dNTP synthesis was investigated by measuring dNTP levels in asynchronous and synchronized wild-type and Δtrx1 Δtrx2 yeast. In contrast to wild-type cells, Δtrx1 Δtrx2 cells were unable to accumulate or maintain high levels of dNTPs when α-factor- or cdc15-arrested cells were allowed to reenter the cell cycle. At 80 min after release, when the fraction of cells in S phase was maximal, the dNTP pools in Δtrx1 Δtrx2 cells were 60% that of wild-type cells. The data suggest that, in the absence of thioredoxin, cells cannot support the high rate of dNTP synthesis required for efficient DNA synthesis during S phase. The results constitute in vivo evidence for thioredoxin being a physiologically relevant electron donor for ribonucleotide reductase during DNA precursor synthesis.