title: Classification of test agent-specific effects in the Syrian hamster embryo assay (pH 6.7) using infrared spectroscopy with computational analysis.
abstract: The Syrian hamster embryo (SHE) cell transformation assay (pH 6.7) has utility in the assessment of potential chemical carcinogenicity (both genotoxic and non-genotoxic mechanisms of action). The assay uses morphological transformation as an end point and has a reported sensitivity of 87%, specificity of 83% and overall concordance of 85% with in vivo rodent bioassay data. However, the scoring of morphologically transformed SHE cells is subjective. We treated SHE cells grown on low-E reflective slides with benzo[a]pyrene, 3-methylcholanthrene, anthracene, N-nitroso-N-methylnitroguanidine, ortho-toluidine HCl, 2,4-diaminotoluene or D-mannitol for 7 days before fixation with methanol. Identified colonies were interrogated by acquiring a minimum of five infrared (IR) spectra per colony using attenuated total reflection Fourier-transform IR spectroscopy. Individual IR spectra were acquired over a spatial area of approximately 250 × 250 μm. Resultant data were analysed using Fisher's linear discriminant analysis and feature histogram algorithms to extract classifying biomarkers of test agent-specific effects or transformation in SHE cells. Clustering of spectral points suggested co-segregation or discrimination of test agent categories based on mechanism of action. Towards transformation, unifying alterations were associated with alterations in the Amide I and Amide II peaks; these were consistently major classifying biomarkers for transformed versus non-transformed SHE cells. Our approach highlights a novel method towards objectively screening and classifying SHE cells, be it to ascertain test agent treatment based on mechanism of action or transformation.
authors.affiliation: Centre for Biophotonics, Lancaster Environment Centre, Lancaster University, Lancaster, UK,
authors.forename: Abdullah A
authors.initials: AA
authors.lastname: Ahmadzai
authors.forename: Júlio
authors.initials: J
authors.lastname: Trevisan
authors.forename: Weiyi
authors.initials: W
authors.lastname: Pang
authors.forename: Imran I
authors.initials: II
authors.lastname: Patel
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Fullwood
authors.forename: Shannon W
authors.initials: SW
authors.lastname: Bruce
authors.forename: Kamala
authors.initials: K
authors.lastname: Pant
authors.forename: Paul L
authors.initials: PL
authors.lastname: Carmichael
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Scott
authors.forename: Francis L
authors.initials: FL
authors.lastname: Martin
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002273:Carcinogens / Q000145:classification* / Q000633:toxicity; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D006224:Cricetinae; D003627:Data Interpretation, Statistical; D004622:Embryo, Mammalian / Q000166:cytology; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D008647:Mesocricetus; D009152:Mutagenicity Tests / Q000379:methods; D009153:Mutagens / Q000145:classification* / Q000633:toxicity; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D015415:Biomarkers; D002273:Carcinogens; D009153:Mutagens