Probing single-tumor cell interactions with different-age type I collagen networks by synchrotron-based Fourier transform infrared microspectroscopy

We report here on a first study using synchrotron radiation-based Fourier transform infrared micro-spectroscopy and imaging to investigate HT1080 human fibrosarcoma cells grown onto different-aged type I collagen networks. Spectral images were analyzed with k-means and fuzzy C-means (FCM) clustering algorithms. K-means delineated tumor cells from their surrounding collagen networks and the latter as a function of age mainly due to specific changes in the sugar absorption region. The FCM analysis gave a better nuance of the spectral images. A progression of the biochemical information was observed upon going from the cellular compartments to the pericellular contact regions and to the intact collagens of the different age groups. Two spectral markers based on sugar and protein bands via the intensity ratio (I-1032/I-1655) and band area ratio (A(sugar)/A(amide) (II)), showed an increase in advanced glycation endproducts (AGEs) with age. A clear-separation of the three age groups was obtained for spectra originating from the peripheral contact areas mainly due to changes in protein band intensities. The above-described markers decreased to constant levels for the three conditions indicating a masking of the biochemical information. These results hold promises to better understand the impact of age on tumor progression processes while highlighting new markers of the tumor cell invasion front. c The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.