Glycolipids of Metastatic Tissue in Liver from Colon Cancer: Appearance of Sialylated Lex and Lex Lipids

Glycolipids of metastatic tissue in liver from colon cancer were separated by HPLC and their structures were analyzed. Neutral glycolipid was composed of five major components. Four of them showed similar mobilities to GlcCer, LacCer, Gb3Cer, and nLc4Cer on TLC. The structure of the fifth major component was analyzed by exo-glycosidase treatments, 400 MHz proton NMR spectrometry, gas chromatography-mass spectrometry of the methylated sugars, and immunostaining on a TLC-plate, and concluded to be Ga1β1Fuca1∖43GlcNAβ1-3Ga1β1-4Glcβ1-1Cer(Lexglcolipid). Ganglioside was composed of two major components. One of them was identical with GM3. The structure of the second ganglioside was analyzed by exo-glycosidase treatment, immunostaining on a TLC-plate, and gas chromatography-mass spectrometry of methylated sugars, and concluded to be NeuAcα2-3Galβ1∖Fucα1G34lcNAcβ1-3Galβ1-4Glcβ1-1Cer (sialyl-Lex glycolipid). These Lex and sialyl-Lex structure-containing lipids accounted for about 12% of the neutral glycolipid fraction and 42% of the ganglioside fraction, respectively. From these results, it appears that the biosynthetic pathway for Lex structure-containing lipids is activated in colon cancer.