Glycoproteomics Identifies Plexin-B3 as Targetable Cell Surface Protein Required for Growth and Invasion of Triple Negative Breast Cancer Cells

Driven by the lack of targeted therapies, triple negative breast cancers (TNBC) have the worst overall survival of all breast cancer subtypes. Considering cell surface proteins are favorable drug targets and are predominantly glycosylated, glycoproteome profiling has significant potential to facilitate the identification of much-needed drug targets for TNBC. Here, we performed N-glycoproteomics on six TNBC and five normal control (NC) cell lines using hydrazide-based enrichment. Quantitative proteomics and integrative data mining led to the discovery of Plexin-B3 (PLXNB3), a previously undescribed TNBC-enriched cell surface protein. Furthermore, siRNA knock-down and CRISPR-Cas9 editing of in vitro and in vivo models show that PLXNB3 is required for TNBC cell line growth, invasion, and migration. Altogether, we provide insight into N-glycoproteome remodeling associated with TNBC and functional evaluation of an extracted target, which indicate the surface protein PLXNB3 as a potential therapeutic target for TNBC. HighlightsO_LIIn-depth N-glycoproteomic profiles of six TNBC and five NC cell line models C_LIO_LIIdentification of PLXNB3 as a novel TNBC-enriched cell surface protein C_LIO_LIPLXNB3 affects growth, invasion, and migration in TNBC models C_LIO_LIPLXNB3 inhibition represents a targeted treatment option for TNBC C_LI