engleski

Ganglioside Composition and Structure Analysis in Human Dysembryoplastic Neuroepithelial Tumor

Gangliosides, a complex group of sialylated glycosphingolipids, are plasma membrane components involved in cell-cell and cell-matrix interactions. They are especially abundant in the mammalian brain tissue and they participate in numerous physiological processes. Glycosphingolipid metabolism abnormalities are implicated in the initial oncogenic transformation and tumor progression, resulting in different ganglioside expression in tumor, compared with normal brain tissues. Elucidating the role of tumor-associated gangliosides in transformed cells presents a significant factor in current cancer research. Compositional and structural analysis of ganglioside mixture from dysembryoplastic neuroepithelial tumor (DNET) was performed. Total gangliosides were isolated and purified as native mixtures from tissue homogenates and spectrophotometrically quantified. HPTLC was used for compositional analysis. MS screening and sequencing analyses were carried out on a High Capacity Ion Trap Ultra, coupled with fully automated chip-based nanoelectrospray NanoMate robot. The total GG content determined in tumor (DNET) sample was approximately 10 times lower than in the normal adult human brain. The HPTLC pattern of tumor was highly distinctive from normal brain tissue. MS screening of the analyzed tumor sample revealed complex ganglioside composition, confirming the presence of GG species previously reported as tumor-associated ones (O-acetylated GD3, di-O-Ac-GD3). Unusual minor species such as O-Ac- and di-O-Ac-GD1, GT1 and GQ1, Fuc-GQ1, GalNAc-GT2, GalNAc-GT1, O-Ac-GP1 and GH1 were also detected. These results confirm the applied analytical strategies as a powerful GG fingerprinting tool for identification of biomarker species related to normal vs. pathological changes in the brain.

gangliosides; human brain; brain tumors; HPTLC; mass spectrometry

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