TY - JOUR
T1 - CRISPR-screen identifies ZIP9 and dysregulated Zn2+ homeostasis as a cause of cancer-associated changes in glycosylation
AU - Rømer, Troels Boldt
AU - Khoder-Agha, Fawzi
AU - Aasted, Mikkel Koed Møller
AU - de Haan, Noortje
AU - Horn, Sabrina
AU - Dylander, August
AU - Zhang, Tao
AU - Pallesen, Emil Marek Heymans
AU - Dabelsteen, Sally
AU - Wuhrer, Manfred
AU - Høgsbro, Christine Flodgaard
AU - Thomsen, Emil Aagaard
AU - Mikkelsen, Jacob Giehm
AU - Wandall, Hans H
N1 - © The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
PY - 2023/1/16
Y1 - 2023/1/16
N2 - In epithelial cancers, truncated O-glycans, such as the Thomson-nouveau antigen (Tn) and its sialylated form (STn), are up-regulated on the cell surface and associated with poor prognosis and immunological escape. Recent studies have shown that these carbohydrate epitopes facilitate cancer development and can be targeted therapeutically; however, the mechanism underpinning their expression remains unclear. To identify genes directly influencing the expression of cancer-associated O-glycans, we conducted an unbiased, positive-selection, whole genome CRISPR knockout-screen using monoclonal antibodies against Tn and STn. We show that knockout of the Zn2+-transporter SLC39A9 (ZIP9), alongside the well-described targets C1GALT1 (C1GalT1) and its molecular chaperone, C1GALT1C1 (COSMC), results in surface-expression of cancer-associated O-glycans. No other gene perturbations were found to reliably induce O-glycan truncation. We furthermore show that ZIP9 knockout affects N-linked glycosylation, resulting in up-regulation of oligo-mannose, hybrid-type, and α2,6-sialylated structures as well as down-regulation of tri- and tetra-antennary structures. Finally, we demonstrate that accumulation of Zn2+ in the secretory pathway coincides with cell-surface presentation of truncated O-glycans in cancer tissue, and that over-expression of COSMC mitigates such changes. Collectively, the findings show that dysregulation of ZIP9 and Zn2+ induces cancer-like glycosylation on the cell surface by affecting the glycosylation machinery.
AB - In epithelial cancers, truncated O-glycans, such as the Thomson-nouveau antigen (Tn) and its sialylated form (STn), are up-regulated on the cell surface and associated with poor prognosis and immunological escape. Recent studies have shown that these carbohydrate epitopes facilitate cancer development and can be targeted therapeutically; however, the mechanism underpinning their expression remains unclear. To identify genes directly influencing the expression of cancer-associated O-glycans, we conducted an unbiased, positive-selection, whole genome CRISPR knockout-screen using monoclonal antibodies against Tn and STn. We show that knockout of the Zn2+-transporter SLC39A9 (ZIP9), alongside the well-described targets C1GALT1 (C1GalT1) and its molecular chaperone, C1GALT1C1 (COSMC), results in surface-expression of cancer-associated O-glycans. No other gene perturbations were found to reliably induce O-glycan truncation. We furthermore show that ZIP9 knockout affects N-linked glycosylation, resulting in up-regulation of oligo-mannose, hybrid-type, and α2,6-sialylated structures as well as down-regulation of tri- and tetra-antennary structures. Finally, we demonstrate that accumulation of Zn2+ in the secretory pathway coincides with cell-surface presentation of truncated O-glycans in cancer tissue, and that over-expression of COSMC mitigates such changes. Collectively, the findings show that dysregulation of ZIP9 and Zn2+ induces cancer-like glycosylation on the cell surface by affecting the glycosylation machinery.
U2 - 10.1093/glycob/cwad003
DO - 10.1093/glycob/cwad003
M3 - Journal article
C2 - 36648436
JO - Glycobiology
JF - Glycobiology
SN - 0959-6658
ER -