Polybrominated Diphenyl Ether-Associated Alterations in Cell Biochemistry as Determined by Attenuated Total Reflection Fourier-Transform Infrared Spectroscopy: a Comparison with DNA-Reactive and/or Endocrine-Disrupting Agents

Abstract

Whether polybrominated diphenyl ethers (PBDEs) induce effects in target cells is increasingly important given that their environmental burdens are rising. Attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy can be used to biochemically signature cells based on the notion that a detailed "biochemical-cell fingerprint" in the form of an infrared (IR) spectrum is derived. By employing subsequent computational approaches such as principal component analysis (PCA) and/or linear discriminant analysis (LDA), data reduction is achieved to allow for the identification of wavenumber-related biomarkers of effect. Clustering of similar spectra (or scores) away from dissimilar ones highlights the variance responsible for discriminating classes. Discriminating biomarkers might include protein conformational changes, structural alterations to DNA/RNA, glycogen content, or protein phosphorylation. Employing this approach,we investigated in MCF-7 cells the dose-related effects of PBDEs (congeners 47, 153, 183, and 209), benzoapyrene (BaP), 2-amino-1-methyl-6-phenylimidazo4,5-bpyridine (PHIP), 17 beta-Oestradiol (E(2)) or lindane (gamma-hexachlorocyclohexane). Cultures concentrated in G(0)/G(1)- or S-phases were treated for 24 h. Following treatment, MCF-7 cells were fixed and applied to IR reflective Low-E windows for interrogation using ATR-FTIR spectroscopy. At concentrations as low as 10(-12) M in culture, significant separation (P