ST6GAL1-mediated sialyl linkage switching in tumor-associated macrophages drives cancer-promoting nanotubes carrying α2,6-sialylation in anti-inflammatory cells

Dipta, P.; Bansal, N.; Sumer-Bayraktar, Z.; Chien, A.; Ugonotti, J.; Chau, T. H.; Anugraham, M.; Kolarich, D.; Tirosh, B.; Kawahara, R.; Thaysen-Andersen, M.

doi:10.1101/2024.11.28.625934

bioRxiv · 10.1101/2024.11.28.625934

ST6GAL1-mediated sialyl linkage switching in tumor-associated macrophages drives cancer-promoting nanotubes carrying α2,6-sialylation in anti-inflammatory cells

Dipta, P.·Bansal, N.·Sumer-Bayraktar, Z.·Chien, A.·Ugonotti, J.·Chau, T. H.·Anugraham, M.·Kolarich, D.·Tirosh, B.·Kawahara, R.·Thaysen-Andersen, M.

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Abstract

Tumor-associated macrophages (TAMs) form functionally diverse populations of innate immune cells in the tumor microenvironment (TME). Pro- and anti-inflammatory TAMs are central to cancer progression by shaping inflammation and immune (im)balance, but it remains unknown if polarization-induced remodeling of the TAM glycocalyx critical for cellular communication occurs within the TME. Taking a systems glycobiology approach, we here firstly used cell surface-focused glycomics and lectin flow cytometry of ex vivo polarized monocyte-derived macrophages to demonstrate profound sialyl linkage switching of the surface N-glycome in pro-inflammatory (2,3-sialo-favored) and anti-inflammatory (2,6-sialo-dominant) macrophages. In contrast, no polarization-induced alterations in sialylation were observed in the surface O-glycome. ST6GAL1 that modifies N-glycans with 2,6-sialylation was elevated in anti-inflammatory compared to levels in pro-inflammatory macrophages providing a mechanistic basis for the sialyl linkage switching, which was supported by ST6GAL1 silencing. Interestingly, SNA-focused lectin cytochemistry of anti-inflammatory macrophages revealed dense networks of dynamic 2,6-sialylated protein-based nanotubules forming inter-connecting cellular structures that were absent in pro-inflammatory macrophages. Temporal ST6GAL1 silencing in anti-inflammatory macrophages caused nanotubule disintegration as evidenced by SNA and biotin fluorescence microscopy. Moreover, live cell recordings of anti-inflammatory macrophages cultured with and without colorectal cancer (CRC) cells showed reduced macrophage motility, attenuated inter-macrophage and macrophage-CRC cell interactions and diminished CRC cell proliferation upon ST6GAL1 disruption indicating functional roles of the 2,6-sialylated nanotubules. Finally, sialyl linkage switching was recapitulated in pro- and anti-inflammatory TAMs from tumor tissues of patients with advanced CRC. We report on the mechanistic basis for and functional consequences of glycocalyx remodeling accompanying TAM polarization.

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Dipta, P., Bansal, N., Sumer-Bayraktar, Z., Chien, A., Ugonotti, J., Chau, T. H., Anugraham, M., Kolarich, D., Tirosh, B., Kawahara, R., Thaysen-Andersen, M.. 2024-12-03. ST6GAL1-mediated sialyl linkage switching in tumor-associated macrophages drives cancer-promoting nanotubes carrying α2,6-sialylation in anti-inflammatory cells. https://doi.org/10.1101/2024.11.28.625934

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