Single-cell tracking demonstrates copper chaperone Atox1 to be required for breast cancer cell migration.

Abstract

Copper ions are needed for several hallmarks of cancer. However, the involved pathways, mechanisms, and copper-binding proteins are mostly unknown. We recently found that cytoplasmic Antioxidant 1 copper chaperone (Atox1), which is up-regulated in breast cancer, is localized at the lamellipodia edges of aggressive breast cancer cells. To reveal molecular insights into a putative role in cell migration, we here investigated breast cancer cell (MDA-MB-231) migration by video microscopy as a function of Atox1. Tracking of hundreds of individual cells (per condition) over a 9-h time series revealed that cell migration velocity and directionality are significantly reduced upon Atox1 silencing in the cells. Because silencing of the copper transporter ATP7A also reduced cell migration, these proteins appear to be on the same pathway, suggesting that their well-known copper transport activity is involved. In-cell proximity ligation assays demonstrated that Atox1, ATP7A, and the proenzyme of lysyl oxidase (LOX; copper-loaded via ATP7A) are all in close proximity and that LOX activity is reduced upon Atox1 silencing in the cells. Since LOX is an established player in cancer cell migration, our results imply that Atox1 mediates breast cancer cell migration via coordinated copper transport in the ATP7A-LOX axis. Because individual cell migration is an early step in breast cancer metastasis, Atox1 levels in tumor cells may be a predictive measure of metastasis potential and serve as a biomarker for copper depletion therapy.

• Authors: Stéphanie Blockhuys, Xiaolu Zhang, Pernilla Wittung-Stafshede
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 117 Issue 4 Pg. 2014-2019 (01 28 2020) ISSN: 1091-6490 [Electronic] United States
• PMID: 31932435 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2020 the Author(s). Published by PNAS.

Chemical References

• ATOX1 protein, human
• Copper Transport Proteins
• Molecular Chaperones
• Copper
• LOX protein, human
• Protein-Lysine 6-Oxidase
• ATP7A protein, human
• Copper-Transporting ATPases

Topics

• Breast Neoplasms (genetics, metabolism, pathology)
• Cell Movement
• Cell Tracking (methods)
• Copper (metabolism)
• Copper Transport Proteins (genetics, metabolism)
• Copper-Transporting ATPases (genetics, metabolism)
• Female
• Gene Expression Regulation, Neoplastic
• Humans
• Molecular Chaperones (genetics, metabolism)
• Protein-Lysine 6-Oxidase (genetics, metabolism)
• Single-Cell Analysis (methods)
• Tumor Cells, Cultured