Glycobiology Advance Access originally published online on February 9, 2007
Glycobiology 2007 17(5):504-515; doi:10.1093/glycob/cwm012
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Human gliosarcoma-associated ganglioside composition is complex and distinctive as evidenced by high-performance mass spectrometric determination and structural characterization
eljka Vukeli
2
454
2 Department of Chemistry and Biochemistry, Faculty of Medicine, University of Zagreb, 
alata 3, 10000 Zagreb, Croatia
3 Croatian Institute for Brain Research, Faculty of Medicine, University of Zagreb, alata 12, 10000 Zagreb, Croatia
4 Institute for Medical Physics and Biophysics, University of Münster, Robert-Koch-Street 31, D-48149 Münster, Germany
5 Department of Neurology, Clinical Hospital Dubrava, Avenija Gojka u
ka bb, 10000 Zagreb, Croatia
6 Advion BioSciences, Ltd, Rowan House, 26-28 Queens Road, Hethersett Norwich Norfolk, NR9 3DB, UK
7 Department of Chemistry and Biology, University of Arad, Revolutiei Blvd. 1, RO-310139, Arad, Romania
8 Mass Spectrometry Laboratory, National Institute for Research and Development in Electrochemistry and Condensed Matter, Plautius Andronescu Str.1, 300224, Timisoara, Romania
1 To whom correspondence should be addressed; Tel: +40-356-437974; Fax: +40-256-204698; e-mail: zamfir{at}uav.ro
Received on December 5, 2006; revised on January 29, 2007; accepted on January 30, 2007
Gangliosides (GGs), involved in malignant alteration and tumor progression/invasiveness, are considered as tumor biomarkers or therapeutic targets. Here, we describe the first systematic GG composition characterization in human gliosarcoma versus normal brain tissue using our recently developed mass spectrometry (MS) methods, based on nano-electrospray (nano-ESI), Fourier-transform ion cyclotron resonance (FT-ICR), and chip nano-ESI quadrupole time-of-flight (QTOF), complemented by thin-layer chromatographic (TLC) analysis and quantification. Combined MS enabled detection and structural assignment of 73 distinct GG species: many more than reported so far for investigated gliomas. Apart from the 7.4-times lower total GG content, gliosarcoma contained all major brain-associated species, however, in very altered proportions, exhibiting a highly distinctive pattern: GD3 (48.9%) > GD1a/nLD1 > GD2/GT3 > GM3 > GT1b > GM2 > GM1a/GM1b/nLM1 > LM1 > GD1b > GQ1b. MS also revealed abundant O-Ac-GD3; its sequencing provided structural evidence to postulate a novel O-Ac-GD3 isomer O-acetylated at the inner Neu5Ac-residue, previously not structurally confirmed. The high sensitivity and mass accuracy permitted the assignment of unusual minor species: GM4, Hex-HexNAc-nLM1, Gal-GD1, Fuc-GT1, GalNAc-GT1, O-Ac-GM3, di- O-Ac-GD3O-Ac-GD3, and O-Ac-GT3, not previously reported as glioma-associated. The gliosarcoma-expressed GA2 might represent a marker distinguishing astrocytic from oligodendroglial tumors. This is, to our knowledge, so far the most complete GG composition characterization of certain glioma, which demonstrates that our MS-based approach could provide essential structural information relevant to glycosphingolipid role(s) in brain tumor biology, differential diagnosis/prognosis and novel treatment concepts.
Key words: biomarkers and target molecules / ganglioside structures / gliosarcoma ganglioside composition / high-performance mass spectrometry / novel O-acetylated GD3 isomer