Spatial Glycomics of a Mouse Model of High-Grade Serous Ovarian Cancer

Ovarian cancer (OC) is one of the deadliest cancers in women, with high mortality rates and a lack of effective screening tools. Among all OC subtypes, high-grade serous carcinoma (HGSC), also known as high-grade serous ovarian cancer, is the most common, making up about 75% of epithelial OC cases. N-Glycans may play essential roles in OC development, as they are involved in cell signaling, recognition, adhesion, and differentiation. In this study, we present spatially resolved N-glycan profiling of HGSC reproductive tissues from a triple mutant (TKO) mouse model (n = 6) using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI). By comparing levels of various N-glycan classes between OC tissues and control tissues (n = 6), we identified potential OC N-glycan biomarkers and developed multivariate statistical models to distinguish HGSC from healthy tissues. Endoglycosidase F3 digestion, followed by a two-step amidation reaction for sialic acid, confirmed that core-fucosylation and α2,6-sialylation were the two most important N-glycan modifications observed in HGSC regions of TKO mice that displayed the most significant differences between controls and TKO. The notable increase in bisecting core-fucosylated N-glycans further supports the hypothesis that protein transport and metastasis are elevated in the later stages of OC. Conversely, the decrease in certain α2,6-sialylated N-glycans suggests potential roles in OC cell signaling, migration, and metastasis, which warrant further validation. Additionally, the rise in high-mannose N-glycans and N-glycan degradation products offered early insights into how abnormal N-glycan levels may contribute to OC progression and disrupt normal cell functions.