Raman micro-spectroscopic investigation of the interaction of cultured HCT116 colon cancer cells with alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase
✍ Scribed by S. Akyuz; A.E. Ozel; K. Balci; T. Akyuz; A. Coker; E.D. Arisan; N. Palavan-Unsal; A. Ozalpan
- Book ID
- 103839795
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 986 KB
- Volume
- 993
- Category
- Article
- ISSN
- 0022-2860
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✦ Synopsis
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 À1 . 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 À1 and 788 cm À1 DNA/ RNA marker bands to that of 1451 cm À1 band are found to decrease by addition of DFMO. Up to 65% reduction in the magnitude of the 1003 cm À1 band, the characteristic phenylalanine ring breathing mode, in comparison to 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 À1 and 850 cm À1 , 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.