Bioengineering / Biyomühendislik
Permanent URI for this collectionhttps://hdl.handle.net/11147/4529
Browse
3 results
Search Results
Article Citation - WoS: 1Citation - Scopus: 1Viability of 3t3-L1 Preadipocytes Is Modulated by the Applied Frequency but Not the Exposure Duration of Low Intensity Vibratory Stimulation(World Scientific Publishing, 2022) Baskan, Öznur; Özçivici, EnginMechanical forces are the integral determinants in cell and tissue homeostasis and regeneration, and they can affect numerous biological process from proliferation to fate determination. Mechanical forces that possess low magnitude and high frequency characteristics are also known as low intensity vibrations (LIVs). These signals were studied widely on many cell types for regenerative purposes, however most of these studies select components of LIV signals (e.g., magnitude, frequency, duration, etc.) arbitrarily. Here, we addressed the effect of LIV applied frequency, LIV daily exposure time and fate induction on the viability of preadipocyte 3T3-L1 cells. For this, we performed a frequency sweep that was ranging from 30Hz to 120Hz with 15Hz increments applied for 5, 10 or 20min during quiescent growth or adipogenesis for up to 10 days. Results suggest that the applied frequency and fate induction was an important determinant of cell viability while daily exposure time had no effect. These findings contribute to the effort of optimizing a relevant mechanical stimulus that can inhibit adipogenesis.Article Citation - WoS: 4A Src/Abl Kinase Inhibitor, Bosutinib, Downregulates and Inhibits Parp Enzyme and Sensitizes Cells To the DNA Damaging Agents(Türk Biyokimya Derneği, 2018) Kırmızıbayrak, Petek Ballar; İlhan, Recep; Yılmaz, Sinem; Günal, Selin; Tepedelen, Burcu ErbaykentBackground: Poly(ADP-ribosyl)ation (PARylation) catalyzed mainly by PARP1 is a highly regulated posttranslational modification associated with several pathways in cellular physiology and genotoxic deoxyribonucleic acid (DNA) damage response. PAR polymers and PARP enzyme function in DNA integrity maintenance and several PARP inhibitors have entered clinical phase studies for cancer therapies. Material and methods: The effect of bosutinib, a dual Src/Abl kinase inhibitor, on PARylation was fluorometrically measured. The cytotoxic and chemosensitizing effects were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The levels of DNA repair proteins and PARP enzyme were examined by immunoblotting. Results: In this study, bosutinib is characterized as a novel PARP inhibitor. Bosutinib inhibited oxidative stress-induced cellular PARylation and nuclear foci formation by downregulating PARP1 levels. Bosutinib was found to be more cytotoxic on Capan1 cells with BRCA2 mutation. Furthermore by acting as a chemosensitizer, bosutinib enhanced the cytotoxicity of doxorubicin (DOXO) and etoposide (ETP) by decreasing phosphorylation of DNA repair enzymes checkpoint kinase 1 (Chk1) and ataxia-telangiectasia mutated (ATM). Conclusion: By inhibition of both PARP and DNA damage checkpoint kinases, bosutinib increased the phospho-H2AX levels, an early indicator of DNA double strand breaks.Article Citation - WoS: 3Citation - Scopus: 4Applicability of Low-Intensity Vibrations as a Regulatory Factor on Stem and Progenitor Cell Populations(Bentham Science Publishers, 2020) Baskan, Öznur; Karadaş, Özge; Meşe, Gülistan; Özçivici, EnginPersistent and transient mechanical loads can act as biological signals on all levels of an organism. It is therefore not surprising that most cell types can sense and respond to mechanical loads, similar to their interaction with biochemical and electrical signals. The presence or absence of mechanical forces can be an important determinant of form, function and health of many tissue types. Along with naturally occurring mechanical loads, it is possible to manipulate and apply external physical loads on tissues in biomedical sciences, either for prevention or treatment of catabolism related to many factors, including aging, paralysis, sedentary lifestyles and spaceflight. Mechanical loads consist of many components in their applied signal form such as magnitude, frequency, duration and intervals. Even though high magnitude mechanical loads with low frequencies (e.g. running or weight lifting) induce anabolism in musculoskeletal tissues, their applicability as anabolic agents is limited because of the required compliance and physical health of the target population. On the other hand, it is possible to use low magnitude and high frequency (e.g. in a vibratory form) mechanical loads for anabolism as well. Cells, including stem cells of the musculoskeletal tissue, are sensitive to high frequency, low-intensity mechanical signals. This sensitivity can be utilized not only for the targeted treatment of tissues, but also for stem cell expansion, differentiation and biomaterial interaction in tissue engineering applications. In this review, we reported recent advances in the application of low-intensity vibrations on stem and progenitor cell populations. Modulation of cellular behavior with low-intensity vibrations as an alternative or complementary factor to biochemical and scaffold induced signals may represent an increase of capabilities in studies related to tissue engineering.