title: Malignancy-associated metabolic profiling of human glioma cell lines using 1H NMR spectroscopy.
abstract: BACKGROUND
  Ambiguity in malignant transformation of glioma has made prognostic diagnosis very challenging. Tumor malignant transformation is closely correlated with specific alterations of the metabolic profile. Exploration of the underlying metabolic alterations in glioma cells of different malignant degree is therefore vital to develop metabolic biomarkers for prognosis monitoring.
  
  
  METHODS
  We conducted (1)H nuclear magnetic resonance (NMR)-based metabolic analysis on cell lines (CHG5, SHG44, U87, U118, U251) developed from gliomas of different malignant grades (WHO II and WHO IV). Several methods were applied to analyze the (1)H-NMR spectral data of polar extracts of cell lines and to identify characteristic metabolites, including principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), fuzzy c-means clustering (FCM) analysis and orthogonal projection to latent structure with discriminant analysis (OPLS-DA). The expression analyses of glial fibrillary acidic protein (GFAP) and matrix metal proteinases (MMP-9) were used to assess malignant behaviors of cell lines. GeneGo pathway analysis was used to associate characteristic metabolites with malignant behavior protein markers GFAP and MMP-9.
  
  
  RESULTS
  Stable and distinct metabolic profiles of the five cell lines were obtained. The metabolic profiles of the low malignancy grade group (CHG5, SHG44) were clearly distinguished from those of the high malignancy grade group (U87, U118, U251). Seventeen characteristic metabolites were identified that could distinguish the metabolic profiles of the two groups, nine of which were mapped to processes related to GFAP and MMP-9. Furthermore, the results from both quantitative comparison and metabolic correlation analysis indicated that the significantly altered metabolites were primarily involved in perturbation of metabolic pathways of tricarboxylic acid (TCA) cycle anaplerotic flux, amino acid metabolism, anti-oxidant mechanism and choline metabolism, which could be correlated with the changes in the glioma cells' malignant behaviors.
  
  
  CONCLUSIONS
  Our results reveal the metabolic heterogeneity of glioma cell lines with different degrees of malignancy. The obtained metabolic profiles and characteristic metabolites are closely associated with the malignant features of glioma cells, which may lay the basis for both determining the molecular mechanisms underlying glioma malignant transformation and exploiting non-invasive biomarkers for prognosis monitoring.
authors.forename: Wei
authors.initials: W
authors.lastname: Shao
authors.forename: Jinping
authors.initials: J
authors.lastname: Gu
authors.forename: Caihua
authors.initials: C
authors.lastname: Huang
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.forename: Huiying
authors.initials: H
authors.lastname: Huang
authors.forename: Zicheng
authors.initials: Z
authors.lastname: Huang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Lin
authors.forename: Wensheng
authors.initials: W
authors.lastname: Yang
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.affiliation: Chenggong Hospital and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China. dhlin@xmu.edu.cn.
authors.forename: Donghai
authors.initials: D
authors.lastname: Lin
authors.forename: Tianhai
authors.initials: T
authors.lastname: Ji
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D045744:Cell Line, Tumor; D005910:Glioma / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D055442:Metabolome; D055432:Metabolomics / Q000379:methods; D025341:Principal Component Analysis; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods*
chemical_list: D014408:Biomarkers, Tumor