Characterization of Chlorogenic Acid as a Two-Photon Fluorogenic Probe that Regulates Glycolysis in Tumor Cells under Hypoxia

High levels of steady-state mitochondrial reactive oxygen species (ROS) and glycolysis are hallmarks of cancer. An improved understanding of interactions between tumor energetics and mitochondrial ROS modulation is useful for the development of new anticancer strategies. Here, we show that the natural product chlorogenic acid (CGA) specifically scavenged abnormally elevated mitochondrial O2•- and exhibited a two-photon fluorescence turn-on response to tumor cells under hypoxia and tumor tissues in vivo. Furthermore, we illustrated that CGA treatment reduced O2•- levels in cells, hampered activation of AMP-activated protein kinase (AMPK), and shifted metabolism from glycolysis to oxidative phosphorylation (OXPHOS), resulting in inhibition of tumor growth under hypoxia. This study demonstrates an efficient two-photon fluorescent tool for real-time assessment of mitochondrial O2•- and a clear link between reducing intracellular ROS levels by CGA treatments and regulating metabolism, as well as undeniably helpful insights for the development of new anticancer strategies.