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: 2Citation - Scopus: 2Vibrational Spectroscopy Unveils Distinct Cell Cycle Features of Cancer Stem Cells in Melanoma(Nature Portfolio, 2025) Uslu, Bensu Ruya; Ozdil, Berrin; Tarhan, Enver; Ozcelik, Serdar; Aktug, Huseyin; Guler, GunnurCancer stem cells (CSCs) play a central role in melanoma growth, resistance to treatment, and relapse, however, their dynamic regulatory behavior remains poorly understood. Vibrational spectroscopy offers a unique, label-free approach to investigate cellular heterogeneity at the molecular level. Here, we explored the biochemical and regulatory dynamics of CSCs identified by using a time-course design, integrating infrared and Raman spectroscopies with cell cycle analysis and immunocytochemistry targeting the checkpoint proteins p16 and p21. CSCs, non-cancer stem cells (NCSCs), and bulk CHL-1 melanoma cells were monitored at 11, 24, 48, and 72 h. CSCs showed a steady S-phase with an early rise in p16 followed by a subsequent increase in p21 expression, indicating a dynamic state of cell cycle checkpoints. In contrast, NCSCs and CHL-1 cells showed more transient p16/p21 expression and CHL-1 exhibited a marked p16 increase at 24 h. Spectroscopic analysis revealed that CSCs exhibited distinct vibrational profiles, predominantly in the nucleic acid-, protein- and lipid-associated regions. These differences were further supported by principal component and hierarchical clustering analyses, which consistently distinguished CSCs from NCSCs. Our findings underline the potential of vibrational spectroscopy to sensitively detect CSC-specific regulatory patterns and support its use in detecting new therapeutic targets in melanoma.Article Citation - WoS: 24Citation - Scopus: 25Investigation of the Structure of Alpha-Lactalbumin Protein Nanotubes Using Optical Spectroscopy(Cambridge University Press, 2014) Tarhan, Özgür; Tarhan, Enver; Harsa, ŞebnemAlpha-lactalbumin (α-la) is one of the major proteins in whey. When partially hydrolysed with Bacillus licheniformis protease, it produces nanotubular structures in the presence of calcium ions by a self-assembly process. This study presents investigation of α-la protein structure during hydrolysis and nanotube formation using optical spectroscopy. Before spectroscopic measurements, nanotubes were examined with microscopy. The observed α-la nanotubes (α-LaNTs) were in the form of regular hollo strands with a diameter of about 20 nm and the average length of 1 μm. Amide and backbone vibration bands of the Raman spectra displayed remarkable conformational changes in α and β domains in the protein structure during nanotube growth. This was confirmed by the Fourier-transform infrared (FTIR) spectroscopy data. Also, FTIR analysis revealed certain bands at calcium (Ca++) binding sites of COO- groups in hydrolysed protein. These sites might be critical in nanotube elongation.