Browsing by Author "Guler, Gunnur"

Now showing 1 - 6 of 6

Biomolecular Fingerprints of the Effect of Zoledronic Acid on Prostate Cancer Stem Cells: Comparison of 2d and 3d Cell Culture Models
(Elsevier Science inc, 2024) Guler, Gunnur; Acikgoz, Eda; Mukhtarova, Guenel; Oktem, Gulperi
Revealing the potential of candidate drugs against different cancer types without disrupting normal cells depends on the drug mode of action. In the current study, the drug response of prostate cancer stem cells (PCSCs) to zoledronic acid (ZOL) grown in two-dimensional (2D) and three-dimensional (3D) culture systems was compared using Fourier transform-infrared (FT-IR) spectroscopy which is a vibrational spectroscopic technique, supporting by biochemical assays and imaging techniques. Based on our data, in 2D cell culture conditions, the ZOL treatment of PCSCs isolated according to both C133 and CD44 cell surface properties induced early/late apoptosis and suppressed migration ability. The CD133 gene expression and protein levels were altered, depending on culture systems. CD133 expression was significantly reduced in 2D cells upon ZOL treatment. FT-IR data revealed that the integrity, fluidity, and ordering/disordering states of the cell membrane and nucleic acid content were altered in both 2D and 3D cells after ZOL treatment. Regular protein structures decrease in 2D cells while glycogen and protein contents increase in 3D cells, indicating a more pronounced cytotoxic effect of ZOL for 2D cells. Untreated 3D PCSCs exhibited an even different spectral profile associated with IR signals of lipids, proteins, nucleic acids, and glycogen in comparison to untreated 2D cells. Our study revealed significant differences in the drug response and cellular constituents between 2D and 3D cells. Exploring molecular targets and/or drug-action mechanisms is significant in cancer treatment approaches; thus, FT-IR spectroscopy can be successfully applied as a novel drug-screening method in clinical research.
Deciphering the Biochemical Similarities and Differences Among Mouse Embryonic Stem Cells, Somatic and Cancer Cells Using Atr-Ftir Spectroscopy
(Royal Soc Chemistry, 2018) Guler, Gunnur; Acikgoz, Eda; Yavasoglu, N. Ulku Karabay; Bakan, Buket; Goormaghtigh, Erik; Aktug, Huseyin
Cellular macromolecules play important roles in cellular behaviors and biological processes. In the current work, cancer (KLN205), normal (MSFs) and mouse embryonic stem cells (mESCs) are compared using ATR-FTIR spectroscopy. Modifications in the composition, concentration, structure and function-related changes in the cellular components were deciphered using the infrared spectra. Our results revealed that cancer and embryonic stem cells are very similar but highly different from the normal cells based on the spectral variations in the protein, lipid, carbohydrate and nucleic acid components. The longest lipid acyl chains exist in mESCs, while cancer cells harbor the lowest lipid amount, short lipid acyl chains, a high content of branched fatty acids and thin cell membranes. The highest cellular growth rate and accelerated cell divisions were observed in the cancer cells. However, the normal cells harbor low nucleic acid and glycogen amounts but have a higher lipid composition. Any defect in the signaling pathways and/or biosynthesis of these cellular parameters during the embryonic-to-somatic cell transition may lead to physiological and molecular events that promote cancer initiation, progression and drug resistance. We conclude that an improved understanding of both similarities and differences in the cellular mechanisms among the cancer, normal and mESCs is crucial to develop a potential clinical relevance, and ATR-FITR can be successfully used as a novel approach to gain new insights into the stem cell and cancer research. We suggest that targeting the cellular metabolisms (glycogen and lipid) can provide new strategies for cancer treatment.
The Effect of Extracellular Matrix on the Differentiation of Mouse Embryonic Stem Cells
(Wiley, 2020) Ozdil, Berrin; Guler, Gunnur; Acikgoz, Eda; Kocaturk, Duygu Calik; Aktug, Huseyin
Embryonic stem cells (ESCs) are promising research materials to investigate cell fate determination since they have the capability to differentiate. Stem cell differentiation has been extensively studied with various microenvironment mimicking structures to modify cellular dynamics associated with the cell-extracellular matrix (ECM) interactions and cell-cell communications. In the current study, our aim was to determine the effect of microenvironmental proteins with different concentrations on the capacity and differentiation capability of mouse ESCs (mESCs), combining the biochemical assays, imaging techniques, Fourier transform infrared (FTIR) spectroscopy, and unsupervised multivariate analysis. Based on our data, coating the surface of mESCs with Matrigel, used as an acellular matrix substrate, resulted in morphological and biochemical changes. mESCs exhibited alterations in their phenotype after growing on the Matrigel-coated surfaces, including their differentiation capacity, cell cycle phase pattern, membrane fluidity, and metabolic activities. In conclusion, mESCs can be stimulated physiologically, chemically, or mechanically to convert them a new phenotype. Thus, identification of ESCs' behavior in the acellular microenvironment could be vital to elucidate the mechanism of diseases. It might also be promising to control the cell fate in the field of tissue engineering.
Effect of Flavopiridol on Cell Cycle, Apoptosis and Biomolecule Structure Changes in Breast Cancer Stem Cells
(Galenos Publ House, 2020) Acikgoz, Eda; Guler, Gunnur; Oktem, Gulperi
Objective: Cancer stem cells (CSCs) are a small population in cancer, which are responsible for therapeutic resistance, relapse and metastasis. Flavopiridol has antitumor activity against various types of cancer cells. The mechanism of action of flavopiridol on CD44+/CD24- breast CSCs has not yet been fully elucidated. The aim of this study was to evaluate the mechanism of action of flavopiridol on breast CSCs (BCSC) in terms of apoptosis, cell cycle and biomolecular changes. Methods: In human breast cancer, cells with CD44+/CD24-markers were isolated from MCF-7 cell line using flow cytometry. The induction of apoptosis was investigated by Annexin-V. The effect of flavopiridol on cell cycle arrest was determined and the percent of cell populations at G0/G1, S and G2/M cycles were identified. The effect of the drug on three-dimensional cell cultures was investigated using a multicellular tumor spheroid model. In addition, the effect of flavopiridol on biomolecules has been evaluated using Fourier transform infrared (FTIR) spectroscopy, which has recently been used effectively in various scientific fields. Results: Flavopiridol especially induced early apoptosis. Cell cycle analyses revealed that flavopiridol induced cell cycle arrest in G0/G1 phase. Decreased number and diameter of spheroids was observed following flavopiridol treatment. ATR-FTIR data showed that treatment with flavopiridol led to significant changes in nucleic acids. Conclusion: According to the data obtained in this study, flavopiridol exhibits anticancer effects by altering the structure/expression level of nucleic acids and changing cell cycle progression and inducing apoptosis. These finding reveals that flavopiridol can be an effective antitumor agent for the treatment of breast cancer after in vivo and phase studies are completed.
Glycogen Synthase Kinase-3 Inhibition in Glioblastoma Multiforme Cells Induces Apoptosis, Cell Cycle Arrest and Changing Biomolecular Structure
(Pergamon-elsevier Science Ltd, 2019) Acikgoz, Eda; Guler, Gunnur; Camlar, Mahmut; Oktem, Gulperi; Aktug, Huseyin
Glioblastoma multiforme (GBM) is the most malignant and aggressive primary human brain tumors. The regulatory pathways of apoptosis are altered in GBMs, leading to a survival advantage of the tumor cells. Thus, identification of target molecules, which are effective in triggering of the cell death mechanisms in GBM, is an essential strategy for therapeutic purposes. Glycogen synthase kinase-3 (GSK-3) plays an important role in apoptosis, proliferation and cell cycle. This study focused on the effect of GSK-3 inhibitor IX in the GBM cells. Apoptosis induction was determined by Annexin-V assay, multicaspase activity and immunofluorescence analyses. Concentration-dependent effects of GSK-3 inhibitor IX on the cell cycle were also evaluated. Moreover, the effect of GSK inhibitor on the cellular biomolecules was assessed by using ATR-FTIR spectroscopy. Our assay results indicated that GSK-3 inhibitor IX induces apoptosis, resulting in a significant increase in the expression of caspase-3 and caspase-8 proteins. Cell cycle analyses revealed that GSK-3 inhibitor IX leads to dose -dependent G2/M-phase cell cycle arrest. Based on the FTIR data, treatment of GBM cells causes dysregulation in the carbohydrate metabolism and induces apoptotic cell death which was characterized by the spectral alterations in nucleic acids, an increment in the lipid amount with disordering state and compositional changes in the cellular proteins. These findings suggest that GSK-3 inhibitor IX exhibits anti-cancer effects by inducing apoptosis and changing biomolecular structure of membrane lipids, carbohydrates, nucleic acids and proteins, and thus, may be further evaluated as a potential effective candidate agent for the GBM combination therapies. (C) 2018 Elsevier B.V. All rights reserved.
Surface Characterization Techniques
(Wiley-v C H verlag Gmbh, 2017) Erdogan, Gokhan; Guler, Gunnur; Kilic, Tugba; Kilic, Duygu O.; Erdogan, Beyhan; Tosun, Zahide; Karaman, Mustafa