A histochemical approach to activity-based copper sensing reveals cuproplasia-dependent vulnerabilities in cancer
Date
2025-01-15
Journal Title
Journal ISSN
Volume Title
Publisher
Proceedings of the National Academy of Sciences
Abstract
Significance
Copper is an essential element for life, where it mediates copper-dependent cell growth and proliferation (cuproplasia) and cell death (cuproptosis) processes that underpin health and disease. We present a histochemical activity-based sensing strategy that enables systematic profiling of bioavailable copper levels, termed the labile copper pool, across many cell lines in parallel to assess their copper dependencies. We identified that cancer cells with heightened activation of the antioxidant response transcription factor NRF2 have reciprocally lower levels of labile Cu(I). In turn, these cells are more susceptible to cell death induced by copper chelation. By revealing a cuproplasia-dependent vulnerability in cancer, this work showcases the utility of chemical copper detection methods for studying metals in biology and medicine.
Abstract
Copper is an essential nutrient for sustaining vital cellular processes spanning respiration, metabolism, and proliferation. However, loss of copper homeostasis, particularly misregulation of loosely bound copper ions which are defined as the labile copper pool, occurs in major diseases such as cancer, where tumor growth and metastasis have a heightened requirement for this metal. To help decipher the role of copper in the etiology of cancer, we report a histochemical activity-based sensing approach that enables systematic, high-throughput profiling of labile copper status across many cell lines in parallel. Coppermycin-1 reacts selectively with Cu(I) to release puromycin, which is then incorporated into nascent peptides during protein translation, thus leaving a permanent and dose-dependent marker for labile copper that can be visualized with standard immunofluorescence assays. We showcase the utility of this platform for screening labile Cu(I) pools across the National Cancer Institute’s 60 (NCI-60) human tumor cell line panel, identifying cell types with elevated basal levels of labile copper. Moreover, we use Coppermycin-1 to show that lung cancer cells with heightened activation of nuclear factor-erythroid 2-related factor 2 (NRF2) possess lower resting labile Cu(I) levels and, as a result, have reduced viability when treated with a copper chelator. This work establishes that methods for labile copper detection can be used to assess cuproplasia, an emerging form of copper-dependent cell growth and proliferation, providing a starting point for broader investigations into the roles of transition metal signaling in biology and medicine.
Description
This article was originally published in Proceedings of the National Academy of Sciences. The version of record is available at: https://doi.org/10.1073/pnas.2412816122.
© 2025 the Author(s). Published by PNAS. This article is distributed under Creative Commons Attribution- NonCommercial-NoDerivatives License 4.0 (CC BY- NC- ND).
Keywords
activity-based sensing, histochemical copper prob, transition metal signaling, cancer metabolism, antioxidant regulation
Citation
M.S. Messina, L. Torrente, A.T. Pezacki, H.I. Humpel, E.L. Li, S.G. Miller, O. Verdejo-Torres, T. Padilla-Benavides, D.C. Brady, D.W. Killilea, A.N. Killilea, M. Ralle, N.P. Ward, J. Ohata, G.M. DeNicola, & C.J. Chang, A histochemical approach to activity-based copper sensing reveals cuproplasia-dependent vulnerabilities in cancer, Proc. Natl. Acad. Sci. U.S.A. 122 (3) e2412816122, https://doi.org/10.1073/pnas.2412816122 (2025).