Glycan Metabolic Fluorine Labeling for In Vivo Visualization of Tumor Cells and In Situ Assessment of Glycosylation Variations

Abstract

The abnormality in the glycosylation of surface proteins is critical for the growth and metastasis of tumors and their capacity for immunosuppression and drug resistance. This anomaly offers an entry point for real‐time analysis on glycosylation fluctuations. In this study, we report a strategy, glycan metabolic fluorine labeling (MEFLA), for selectively tagging glycans of tumor cells. As a proof of concept, we synthesized two fluorinated unnatural monosaccharides with distinctive 19F chemical shifts (Ac4ManNTfe and Ac4GalNTfa). These two probes could undergo selective uptake by tumor cells and subsequent incorporation into surface glycans. This approach enables efficient and specific 19F labeling of tumor cells, which permits in vivo tracking of tumor cells and in situ assessment of glycosylation changes by 19F MRI. The efficiency and specificity of our probes for labeling tumor cells were verified in vitro with A549 cells. The feasibility of our method was further validated with in vivo experiments on A549 tumor‐bearing mice. Moreover, the capacity of our approach for assessing glycosylation changes of tumor cells was illustrated both in vitro and in vivo. Our studies provide a promising means for visualizing tumor cells in vivo and assessing their glycosylation variations in situ through targeted multiplexed 19F MRI.

In Situ Glycan Analysis and Editing in Living Systems

“…175 Later, this group designed two 19 Fcontaining monosaccharide probes with different 19 F chemical shifts to visualize two glycans in vivo, thereby demonstrating the multiplexing potential of 19 F MRI. 176…”

“…Gao and Lin’s group treated mice with tetra-acetylated N -azidoacetylmannosamine (Ac 4 ManAz) and then a 19 F-containing cyclooctyne probe for glycan imaging . Later, this group designed two 19 F-containing monosaccharide probes with different 19 F chemical shifts to visualize two glycans in vivo, thereby demonstrating the multiplexing potential of 19 F MRI …”

Fluorinated 1,7-DO2A-Based Iron(II) Complexes as Sensitive 19F MRI Molecular Probes for Visualizing Renal Dysfunction in Living Mice

“…Fortunately, 19 F MRI has emerged as a promising alternative complement to 1 H MRI due to 19 F’s excellent sensitivity, 100% natural abundance, and low biological distribution. , These advantages make 19 F MRI a promising tool for providing nearly background-free “hot-spot” images of various targets in living organism. , Unlike 1 H MRI, which could be used without any CA, the performance of imaging probes is critical for 19 F MRI. Currently, many designing strategies have been reported to construct 19 F MRI probes for various targets, − including but not limited to endogenous biomolecules, − gut microbiota, cancer cells, − and immune cells. − However, there are limited reports on the probes for in vivo imaging of renal dysfunction. , Furthermore, the sensitivity of most conventional 19 F probes is not satisfactory due to unoptimized relaxation properties of 19 F nuclei, resulting in low-quality images and long acquisition time, which is not suitable for monitoring rapid ordinary renal functioning . Therefore, it is important and imperative to develop high-performance probes that allow fast 19 F MRI to afford clear images.…”