title: Label-free identification of the glioma stem-like cell fraction using Fourier-transform infrared spectroscopy.
abstract: OBJECTIVE
  Vibrational spectroscopy enables the label-free characterization of cells and tissue by probing the biochemical composition. Here, we evaluated these techniques to identify glioblastoma stem cells.
  
  
  METHODS
  The biochemical fingerprints of glioblastoma cells were established in human cell lines with high and low content of CD133 (cluster of differentiation 133)-positive cells using attenuated total reflection Fourier-transform infrared (ATR FT-IR) on vital cells and FT-IR mapping, which delivers spatially resolved spectroscopic datasets. After data preprocessing, unsupervised cluster analysis was applied. CD133 was addressed with flow cytometry and immunohistochemistry and used as a stemness marker.
  
  
  RESULTS
  In all preparations, the algorithm was able to correctly classify the spectra, differentiating CD133-rich and -poor populations. The main spectral differences were found in the region of 1000 cm(- 1) to 1150 cm(- 1) that can be assigned to vibrations of chemical bonds of DNA, RNA, carbohydrates and phospholipids. Interestingly, this spectral region is a key feature to discern glioblastoma from normal brain parenchyma, as FT-IR spectroscopic mapping of experimental brain tumors demonstrated.
  
  
  CONCLUSIONS
  We were able to show biochemical differences between glioblastoma cell populations with high and low content of cancer stem cells that are presumably related to changes in the RNA/DNA content.
authors.affiliation: Neurosurgery, Carl Gustav Carus University Hospital , Dresden , Germany.
authors.forename: Ortrud
authors.initials: O
authors.lastname: Uckermann
authors.forename: Roberta
authors.initials: R
authors.lastname: Galli
authors.forename: Martin
authors.initials: M
authors.lastname: Anger
authors.forename: Christel
authors.initials: C
authors.lastname: Herold-Mende
authors.forename: Edmund
authors.initials: E
authors.lastname: Koch
authors.forename: Gabriele
authors.initials: G
authors.lastname: Schackert
authors.forename: Gerald
authors.initials: G
authors.lastname: Steiner
authors.forename: Matthias
authors.initials: M
authors.lastname: Kirsch
mesh_terms: D000071916:AC133 Antigen; D015703:Antigens, CD / Q000378:metabolism; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D005910:Glioma / Q000378:metabolism / Q000473:pathology*; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D014411:Neoplastic Stem Cells / Q000473:pathology*; D010455:Peptides / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides
keywords: Glioma; imaging; stem cells; vibrational spectroscopy