A Quantitative Method to Measure Low Levels of ROS in Nonphagocytic Cells by Using a Chemiluminescent Imaging System

• Published in: Oxidative medicine and cellular longevity Vol. 2019; no. 2019; pp. 1 - 11
• Main Authors: Rodriguez, Yelitza A. R., Murphy, James M., Jeong, Kyuho, Kim, Jun-Sub, Lim, Ssang-Taek Steve
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01-01-2019; Hindawi; John Wiley & Sons, Inc; Hindawi Limited
• Subjects: Acetylcysteine - pharmacology; Apoptosis; Biochemistry; Biology; Boron Compounds - pharmacology; Cancer; Cell adhesion & migration; Colon cancer; Cysteine; Focal Adhesion Kinase 1 - metabolism; Free radicals; HT29 Cells; Humans; Immunoblotting; Iodobenzenes - pharmacology; Kinases; Luminol; Measurement; Medicine; Methods; Neutrophils; Onium Compounds - pharmacology; Oxidation; Phosphorylation; Phosphorylation - drug effects; Protein-Tyrosine Kinases - metabolism; Proteins; Reactive Oxygen Species - metabolism; Signal transduction; Signal Transduction - drug effects; Tyrosine
• ISSN: 1942-0900; 1942-0994
• DOI: 10.1155/2019/1754593

Chemiluminescence (CL) is one of the most useful methods for detecting reactive oxygen species (ROS). Although fluorescence dyes or genetically encoded biosensors have been developed, CL is still used due to its high sensitivity, ease of use, and low cost. While initially established and used to measure high levels of ROS in phagocytic cells, CL assays are not ideal for measuring low levels of ROS. Here, we developed a newly modified CL assay using a chemiluminescent imaging system for measuring low concentrations of ROS in nonphagocytic cells. We found that dissolving luminol in NaOH, rather than DMSO, increased the H2O2-induced CL signal and that the addition of 4-iodophenylboronic acid (4IPBA) further increased CL intensity. Our new system also increased the rate and intensity of the CL signal in phorbol 12-myristate 13-acetate- (PMA-) treated HT-29 colon cancer cells compared to those in luminol only. We were able to quantify ROS levels from both cells and media in parallel using an H2O2 standard. A significant benefit to our system is that we can easily measure stimulus-induced ROS formation in a real-time manner and also investigate intracellular signaling pathways from a single sample simultaneously. We found that PMA induced tyrosine phosphorylation of protein tyrosine kinases (PTKs), such as focal adhesion kinase (FAK), protein tyrosine kinase 2 (Pyk2), and Src, and increased actin stress fiber formation in a ROS-dependent manner. Interestingly, treatment with either N-acetyl-L-cysteine (NAC) or diphenyleneiodonium (DPI) reduced the PMA-stimulated phosphorylation of these PTKs, implicating a potential role in cellular ROS signaling. Thus, our newly optimized CL assay using 4IPBA and a chemiluminescent imaging method provides a simple, real-time, and low-cost method for the quantification of low levels of ROS.