Quantitative analysis of NRF2 pathway reveals key elements of the regulatory circuits underlying antioxidant response and proliferation of ovarian cancer cells

• Published in: Journal of biotechnology Vol. 202; pp. 12 - 30
• Main Authors: Khalil, Hilal S., Goltsov, Alexey, Langdon, Simon P., Harrison, David J., Bown, James, Deeni, Yusuf
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2015
• Subjects: Antioxidants; Balancing; Biotechnology; Cell Line, Tumor; Cell Nucleus - metabolism; Control; Cytoplasm - metabolism; Female; Gene Regulatory Networks; Half life; Homeostasis; Humans; Hydrogen Peroxide - metabolism; Hydrogen Peroxide - pharmacokinetics; Intracellular Signaling Peptides and Proteins - metabolism; Kelch-Like ECH-Associated Protein 1; Mathematical modelling; Models, Genetic; NF-E2-Related Factor 2 - metabolism; NRF2 localisation; Ovarian Neoplasms - metabolism; Ovarian Neoplasms - pathology; Oxidation-Reduction; Oxidative stress; Panels; Pathways; Proliferation; Reactive Oxygen Species - metabolism; ROS; Signal Transduction; Systems Biology; Oxidative stress; Mathematical modelling; NRF2 localisation; Proliferation; ROS
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2014.09.027

•Basal cellular ROS correlates with growth rates (μ) and total NRF2 levels.•Ovarian cancer cells have greater nuclear NRF2 and exogenous ROS removal capacity.•Using our data, we developed a mathematical model of antioxidant signalling system.•Modelling of oxidative stress revealed strict control of ROS by NRF2-KEAP1 system.•Nuclear NRF2 dynamic is key factor in genetic regulation of basal ROS in cells. Cells are constantly exposed to Reactive Oxygen Species (ROS) produced both endogenously to meet physiological requirements and from exogenous sources. While endogenous ROS are considered as important signalling molecules, high uncontrollable ROS are detrimental. It is unclear how cells can achieve a balance between maintaining physiological redox homeostasis and robustly activate the antioxidant system to remove exogenous ROS. We have utilised a Systems Biology approach to understand how this robust adaptive system fulfils homeostatic requirements of maintaining steady-state ROS and growth rate, while undergoing rapid readjustment under challenged conditions. Using a panel of human ovarian and normal cell lines, we experimentally quantified and established interrelationships between key elements of ROS homeostasis. The basal levels of NRF2 and KEAP1 were cell line specific and maintained in tight correlation with their growth rates and ROS. Furthermore, perturbation of this balance triggered cell specific kinetics of NRF2 nuclear–cytoplasmic relocalisation and sequestration of exogenous ROS. Our experimental data were employed to parameterise a mathematical model of the NRF2 pathway that elucidated key response mechanisms of redox regulation and showed that the dynamics of NRF2-H2O2 regulation defines a relationship between half-life, total and nuclear NRF2 level and endogenous H2O2 that is cell line specific.