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: [email protected].
PY - 2023/9/1
Y1 - 2023/9/1
N2 - INTRODUCTION: In epithelial cancers, truncated O-glycans, such as the Thomson-nouveau antigen (Tn) and its sialylated form (STn), are upregulated 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.METHODS: 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.RESULTS AND CONCLUSIONS: 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 upregulation of oligo-mannose, hybrid-type, and α2,6-sialylated structures as well as downregulation 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 - INTRODUCTION: In epithelial cancers, truncated O-glycans, such as the Thomson-nouveau antigen (Tn) and its sialylated form (STn), are upregulated 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.METHODS: 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.RESULTS AND CONCLUSIONS: 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 upregulation of oligo-mannose, hybrid-type, and α2,6-sialylated structures as well as downregulation 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.
KW - CRISPR screen
KW - SLC39A9
KW - Tn
KW - cancer antigens
KW - zinc homeostasis
UR - http://www.scopus.com/inward/record.url?scp=85160596824&partnerID=8YFLogxK
U2 - 10.1093/glycob/cwad003
DO - 10.1093/glycob/cwad003
M3 - Journal article
C2 - 36648436
SN - 0959-6658
VL - 33
SP - 700
EP - 714
JO - Glycobiology
JF - Glycobiology
IS - 9
ER -