10.1021/acs.jproteome.9b00429.s002 Wenjing Peng Wenjing Peng Mona Goli Mona Goli Parvin Mirzaei Parvin Mirzaei Yehia Mechref Yehia Mechref Revealing the Biological Attributes of N‑Glycan Isomers in Breast Cancer Brain Metastasis Using Porous Graphitic Carbon (PGC) Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) American Chemical Society 2019 breast cancer brain metastasis role glycan isomers 231 BR 50 N-glycan compositions expression alterations Breast Cancer Brain Metastasis Liquid Chromatography-Tandem Mass Spectrometry breast cancer cells sialylated glycan isomers N-glycan isomer function glycan isomer expressions breast cancer cell lines Porous Graphitic Carbon breast cancer invasion brain-seeking cell line brain cancer cell line breast cancer patients LC-MS PGC brain-seeking cell line 231 BR breast cancer metastasis roles glycan isomers 2019-09-16 12:36:25 Dataset https://acs.figshare.com/articles/dataset/Revealing_the_Biological_Attributes_of_N_Glycan_Isomers_in_Breast_Cancer_Brain_Metastasis_Using_Porous_Graphitic_Carbon_PGC_Liquid_Chromatography-Tandem_Mass_Spectrometry_LC-MS_MS_/9850970 Breast cancer is a leading cancer in women and is considered to be the second-most common metastatic cancer following lung cancer. An estimated 10–16% of breast cancer patients are suffering from brain metastasis, and the diagnostic cases of breast cancer brain metastasis are increasing. Nevertheless, the mechanisms behind this process are still unclear. Aberrant glycosylation has been proved to be related to many diseases and cancer metastasis. However, studies of N-glycan isomer function in breast cancer brain metastasis are limited. In this study, the expressions of N-glycan isomers derived from five breast cancer cell lines and one brain cancer cell line were investigated and compared to a brain-seeking cell line, 231BR, to acquire a better understanding of the role glycan isomers play in breast cancer brain metastasis. The high temperature nanoPGC-LC-MS/MS achieved an efficient isomeric separation and permitted the identification and quantitation of 144 isomers from 50 N-glycan compositions. There were significant expression alterations of these glycan isomers among the different breast cancer cell lines. The increase of total glycan abundance and sialylation level were observed to be associated with breast cancer invasion. With regard to individual isomers, the greatest number of sialylated isomers was observed along with significant expression alterations in 231BR, suggesting a relationship between glycan sialylation and breast cancer brain metastasis. Furthermore, the increase of the α2,6-sialylation level in 231BR likely contributes to the passage of breast cancer cells through the blood-brain barrier, thus facilitating breast cancer brain metastasis. Meanwhile, the upregulation of highly sialylated glycan isomers with α2,6-linked sialic acids were found to be associated with breast cancer metastasis. This investigation of glycan isomer expressions, especially the unique isomeric expression in brain-seeking cell line 231BR, provides new information toward understanding the potential roles glycan isomers play during breast cancer metastasis and more clues for a deeper insight of this bioprocess.