Fourier-transform infrared spectroscopic comparison of cultured human fibroblast and fibrosarcoma cells

Infrared vibration spectroscopy appears to be a more powerful technique for diagnosis than visible or UV spectroscopy. Advantages of IR spectra include: 1) vibrational motion has a smaller tissue absorption coefficient than electronic motion, 2) scattering of infrared radiation has a lower cross section than visible or UV light, (these two facts allow deeper penetration of IR radiation) and 3) vibration spectra provide a better fingerprint of chemical groups present in cells than the unresolved broad electronic spectrum of biological molecules. In the present work, Fourier-transform IR spectroscopy was used to compare cultured human fibroblast and malignant fibrosarcoma cells. Significant differences were observed by comparing the spectra of the normal cells with that of the cancer cells. the PO2 symmetric stretching mode at 1082cm-1 in the cancer cell is reduced in intensity. These observations are similar to those reported previously by Wong et al in comparing the IR spectra of pairs of normal and cancerous cells from the colon and cervix. However, the observed increase in the relative intensity of the symmetric to antisymmetric CH3 bending mode are only found in fibrosarcoma and basal cell carcinoma. The decrease in intensity of the CH2 bending mode relative to that of CH3 mode was observed only for fibrosarcoma cells. This finding with paired human fibroblast and fibrosarcoma cells suggests that fatty acid chains or side chains of protein in the cancer cells are partially degraded leading to more terminal carbon. It is also possible that changes in the environment upon carcinogenesis induces a change in the relative absorption cross sections for the CH3 and CH2 bending vibrations.