A tandem activity- based sensing and labeling strategy reveals antioxidant response element regulation of labile iron pools

• 成果类型: Article
• 署名作者: Pezacki, Aidan T.; Gonciarz, Ryan L.; Okamura, Toshitaka; Matier, Carson D.; Torrente, Laura; Cheng, Ke; Miller, Sophia G.; Ralle, Martina; Ward, Nathan P.; DeNicola, Gina M.; Renslo, Adam R.; Chang, Christopher J.
• 署名单位: University of California System; University of California Berkeley; University of California System; University of California San Francisco; H Lee Moffitt Cancer Center & Research Institute; Oregon Health & Science University; University of California System; University of California San Francisco; UCSF Medical Center; UCSF Helen Diller Family Comprehensive Cancer Center; University of California System; University of California Berkeley; University of California System; University of California Berkeley
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11855
• DOI: 10.1073/pnas.2401579121
• 发表日期: 2024-07-09
• 关键词: fluorescent-probes; ferrous iron; imaging metals; nrf2; cancer; biology; cells; chemistry; sensitivity; ferroptosis

摘要

Iron is an essential element for life owing to its ability to participate in a diverse array of oxidation-reduction reactions. However, misregulation of iron- dependent redox cycling can also produce oxidative stress, contributing to cell growth, proliferation, and death pathways underlying aging, cancer, neurodegeneration, and metabolic diseases. Fluorescent probes that selectively monitor loosely bound Fe(II) ions, termed the labile iron pool, are potentially powerful tools for studies of this metal nutrient; however, the dynamic spatiotemporal nature and potent fluorescence quenching capacity of these bioavailable metal stores pose challenges for their detection. Here, we report a tandem activity- based sensing and labeling strategy that enables imaging of labile iron pools in live cells through enhancement in cellular retention. Iron green- 1 fluoromethyl (IG1-FM) reacts selectively with Fe(II) using an endoperoxide trigger to release a quinone methide dye for subsequent attachment to proximal biological nucleophiles, providing a permanent fluorescent stain at sites of elevated labile iron. IG1-FM imaging reveals that degradation of the major iron storage protein ferritin through ferritinophagy expands the labile iron pool, while activation of nuclear factor- erythroid 2- related factor 2 (NRF2) antioxidant response elements (AREs) depletes it. We further show that lung cancer cells with heightened NRF2 activation, and thus lower basal labile iron, have reduced viability when treated with an iron chelator. By connecting labile iron pools and NRF2-ARE activity to a druggable metal- dependent vulnerability in cancer, this work provides a starting point for broader investigations into the roles of transition metal and antioxidant signaling pathways in health and disease.