Raman Micro-Spectroscopic Investigation Of The Interaction Of Cultured Hct116 Colon Cancer Cells With Alpha-Difluoromethylornithine (Dfmo), An Irreversible Inhibitor Of Ornithine Decarboxylase

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Akyüz, Sevim
Özel, Ayşen
Balcı, Kubilay
Akyüz, Zeki Tanıl
Çoker, Ajda
Arısan, Elif Damla
Palavan-Ünsal, Narçin
Özalpan, Atilla
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Elsevier Science Bv, Po Box 211, 1000 Ae Amsterdam, Netherlands
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The interaction of cultured colon cancer cells with alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase, has been investigated, using Raman micro-spectroscopy, in order to investigate DFMO induced effects. Raman spectra of the cultured HCT116 colon cancer cells treated with DFMO at different concentrations (0, 1, 2.5, 5, and 7.5 mM) were recorded in the range 550-2300 cm(-1). It has been shown that second derivative profile of the raw Raman spectrum of the colon cancer cells (i.e., the original experimental spectrum without any computational corrections) discriminates the weak but sharp bands from the strong, broad fluorescence background, and gives information about the position of the peaks and their band widths. The relative integrated intensities of the 781 cm(-1) and 788 cm(-1) DNA/RNA marker bands to that of 1451 cm(-1) band are found to decrease by addition of DFMO. Up to 65% reduction in the magnitude of the 1003 cm(-1) band, the characteristic phenylalanine ring breathing mode, in comparison 10 that of 1451 band, is observed. The results indicate DFMO induced apoptosis. On the other hand the intensity ratio of the tyrosine Fermi doubled around 830 cm(-1) and 850 cm(-1), which is a marker of hydrogen-bonding state of phenolic OH, is changed. The addition of DFMO may alter the tyrosine environment in cells, and parts of tyrosine residues are exposed. We also observed some modifications in amide I band, pointing out the alterations of the secondary structure of cell proteins by the presence of DFMO. (C) 2011 Elsevier B.V. All rights reserved.
Anahtar kelimeler
colon cancer, cultured cells, eflornithine, alpha-difluoromethylornithine, DFMO, raman micro-spectroscopy, living cells, chemoprevention, proteins, spectra, viruses, kolon kanseri, kültürlenmiş hücreler, eflornitin, alfa-diflorometilornitin, Raman spektroskopisi mikro, yaşayan hücreler, kemoprevensiyon, proteinler, spektrumları, virüsler