Kinetic modeling of H2O2 dynamics in the mitochondria of HeLa cells
| Autor: | Kassi T. Stein, Hadley D. Sikes, Athena N. Nguyen, Sun Jin Moon |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Cultured tumor cells Cancer Treatment Mitochondrion Biochemistry Antioxidants Reaction rate 0302 clinical medicine Cytosol Neoplasms Electrochemistry Medicine and Health Sciences Biology (General) Energy-Producing Organelles Ecology Chemistry Chemical Reactions Mitochondria Computational Theory and Mathematics Oncology Modeling and Simulation Physical Sciences Cell lines Efflux Cellular Structures and Organelles Biological cultures Intracellular Signal Transduction Research Article Programmed cell death QH301-705.5 Kinetics Bioenergetics Redox Models Biological 03 medical and health sciences Cellular and Molecular Neuroscience Oxidation Genetics Humans HeLa cells Molecular Biology Ecology Evolution Behavior and Systematics Computational Biology Biology and Life Sciences Cancers and Neoplasms Hydrogen Peroxide Cell Biology Cell cultures Research and analysis methods 030104 developmental biology Biophysics Reactive Oxygen Species 030217 neurology & neurosurgery Oxidation-Reduction Reactions |
| Zdroj: | PLoS Computational Biology PLoS Computational Biology, Vol 16, Iss 9, p e1008202 (2020) |
| ISSN: | 1553-7358 |
| Popis: | Hydrogen peroxide (H2O2) promotes a range of phenotypes depending on its intracellular concentration and dosing kinetics, including cell death. While this qualitative relationship has been well established, the quantitative and mechanistic aspects of H2O2 signaling are still being elucidated. Mitochondria, a putative source of intracellular H2O2, have recently been demonstrated to be particularly vulnerable to localized H2O2 perturbations, eliciting a dramatic cell death response in comparison to similar cytosolic perturbations. We sought to improve our dynamic and mechanistic understanding of the mitochondrial H2O2 reaction network in HeLa cells by creating a kinetic model of this system and using it to explore basal and perturbed conditions. The model uses the most current quantitative proteomic and kinetic data available to predict reaction rates and steady-state concentrations of H2O2 and its reaction partners within individual mitochondria. Time scales ranging from milliseconds to one hour were simulated. We predict that basal, steady-state mitochondrial H2O2 will be in the low nM range (2–4 nM) and will be inversely dependent on the total pool of peroxiredoxin-3 (Prx3). Neglecting efflux of H2O2 to the cytosol, the mitochondrial reaction network is expected to control perturbations well up to H2O2 generation rates ~50 μM/s (0.25 nmol/mg-protein/s), above which point the Prx3 system would be expected to collapse. Comparison of these results with redox Western blots of Prx3 and Prx2 oxidation states demonstrated reasonable trend agreement at short times (≤ 15 min) for a range of experimentally perturbed H2O2 generation rates. At longer times, substantial efflux of H2O2 from the mitochondria to the cytosol was evidenced by peroxiredoxin-2 (Prx2) oxidation, and Prx3 collapse was not observed. A refined model using Monte Carlo parameter sampling was used to explore rates of H2O2 efflux that could reconcile model predictions of Prx3 oxidation states with the experimental observations. Author summary Cancer is a complex disease that caused the deaths of over 9 million people worldwide in 2018, according to the WHO. While great strides have been made in treating many cancers, effective chemotherapies still carry difficult side effects, motivating the search for more targeted and selective treatments that act minimally in healthy cells. The Selective Cancer Killing Hypothesis is based on the idea that some cancers exist at endogenous levels of reactive oxygen species that are higher than healthy cells, so if a patient were systemically treated with a redox-based chemotherapeutic that raises all cells’ levels of reactive oxygen species, only the cancer cells would cross a toxicity threshold. This hypothesis is attractive because it would minimize side effects in healthy cells, but the quantitative knowledge of endogenous oxidant concentrations that would be helpful in refining and testing this hypothesis is not widely established. Our model predicts the range of relevant hydrogen peroxide concentrations in the mitochondria of the HeLa model cancer cell line and suggests experimental measurements of tumor cells and tissues that may be useful in quantifying steady state concentrations of this oxidant. |
| Databáze: | OpenAIRE |
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