Single-Cell Multiomics Identifies Glycan Epitope LacNAc as a Potential Cell-Surface Effector Marker of Peripheral T Cells in Bladder Cancer Patients

Cancer is a systemic disease continuously monitored and responded to by the human global immune system. Peripheral blood immune cells, integral to this surveillance, exhibit variable phenotypes during tumor progression. Glycosylation, as one of the most prevalent and significant post-translational modifications of proteins, plays a crucial role in immune system recognition and response. Glycan analysis has become a key method for biomarker discovery. LacNAc, a prominent glycosylation modification, regulates immune cell activity and function. Therefore, we applied our previously developed single-cell glycomic multiomics to analyze peripheral blood in cancer patients. This platform utilizes chemoenzymatic labeling with DNA barcodes for detecting and quantifying LacNAc levels at single-cell resolution without altering the transcriptional status of immune cells. For the first time, we systematically integrated single-cell transcriptome, T cell receptor (TCR) repertoire, and glycan epitope LacNAc analyses in tumor-patient-derived peripheral blood. Our integrated analysis reveals that lower-stage bladder cancer patients showed significantly higher levels of LacNAc in peripheral T cells, and peripheral T cells with high levels of cell-surface LacNAc exhibit higher cytotoxicity and TCR clonal expansion. In summary, we identified LacNAc as a potential cell-surface effector marker for peripheral T cells in bladder cancer patients, which enhances our understanding of peripheral immune cells and offers potential advancements in liquid biopsy.