
Charles R. Myers, PhD
Professor; Assistant Director, Center for Disease Prevention Research
Locations
- Pharmacology and Toxicology
Contact Information
General Interests
Education
MS, Microbiology/Biology, University of Wisconsin, Oshkosh, 1985
BS, Carrol College, Waukesha, Wisconsin, 1978
Research Experience
- Chromium Compounds
- Cytochromes c
- Iron
- Manganese Compounds
- Metals
- Metals, Heavy
- Mitochondrial Membrane Transport Proteins
- Oxidative Stress
- Peroxiredoxins
- Reactive Oxygen Species
- Thioredoxin Reductase 1
- Thioredoxins
Methodologies and Techniques
- Blotting, Western
- Cell Culture Techniques
- Electron Transport
- Endoplasmic Reticulum, Smooth
- Membrane Potential, Mitochondrial
- Membrane Proteins
- Molecular Biology
- Oxidation-Reduction
- Oxidative Stress
- Peroxiredoxins
- Spectrophotometry
- Thioredoxins
Educational Expertise
- Anti-Bacterial Agents
- Antibiotics, Antitubercular
- Antifungal Agents
- Antineoplastic Agents
- Antiparasitic Agents
- Antiviral Agents
- Cytochrome P-450 Enzyme System
- Drug Interactions
- Drug Resistance, Microbial
- Pharmacogenetics
- Pharmacology
- Toxicology
Research Interests
The focus of my research has been on redox-active agents, with special emphasis on metals and metal complexes, including factors which affect their redox state and bioavailability, the mechanisms by which they are enzymatically reduced by microbial and human electron transport systems and other enzymes, their toxic and potentially therapeutic effects, their ability to promote reactive species formation, to compromise antioxidant defense mechanisms, and to damage electron transport complexes.
For the past several years, I have studied the ability of metals, metal complexes, electrophiles, and anti-cancer agents to disrupt cellular thiol redox balance, specifically through differential effects on thioredoxin reductase (TrxR), thioredoxins (Trx), peroxiredoxins (Prx), and mitochondrial electron transport. These systems have central roles in protein thiol redox control, oxidant defense, and redox signaling, and are critical to cell survival. I have used these systems as endogenous indicators of redox stress, noting very tight correlation between disruption of their function and loss of clonogenic survival. The thioredoxin-peroxiredoxin system is therefore highly useful as an endogenous indicator of redox stress, and to validate other redox stress indicators. Since there are cytosolic and mitochondrial isoforms, this approach also provides key insights into the subcellular location of redox stress. For example, we determined that chromium(VI), antitumor thiosemicarbazones, and Mito-honokiol preferentially cause early disruption of mitochondrial peroxiredoxin-3 and/or mitochondrial thioredoxin-2, with important implications for cytotoxicity and loss of thiol redox control. In contrast, the electrophile acrolein initially targets cytosolic TrxR1 and Trx1, with higher doses also promoting mitochondrial effects. Inhibitors of TrxR activity such as auranofin and cisplatin can markedly enhance the mitochondrial pro-oxidant effects of thiosemicarbazones. Complementary approaches have included the use of EPR to demonstrate damage to mitochondrial electron transport proteins (e.g. iron-sulfur centers in complex I) and aconitase by some pro-oxidants. Recent collaborative efforts have focused on various agents that cause oxidative stress as a primary mechanism for their antitumor effects including thiosemicarbazones, Mito-honokiol and other mitochondrial-targeted novel compounds, and Magnolia Extract.
Collaborations with Professor Elias Arnér (Karolinska Institute, Stockholm) have generated multiple insights into the diverse redox chemistry of the selenoprotein thioredoxin reductase 1 (TrxR1). While TrxR1 has multiple roles in antioxidant defense, we characterized several pro-oxidant properties including the generation of superoxide by its N-terminal C59/C64 dithiol, and the peroxidase activity of its C497/U498 selenocystine motif. TrxR1 (specifically its flavin/C59 motif) was also shown to have robust activity to reduce antitumor iron(III)-thiosemicarbazones, which promotes their redox-cycling and reactive species generation that are important for their antitumor effects. TrxR1 also reduces Fe(III)-bleomycin and this activity is dependent on its selenocysteine. The marked elevation of TrxR1 in many tumors could contribute to the selective tumor toxicity of these drugs by enhancing their redox activation. We also contributed to studies demonstrating that the conserved Trp114 of TrxR1 is highly susceptible to oxidation. Oxidation of Trp114 promotes oligomerization of TxrR1, and such oligomers are promoted in tumor cells by the anticancer compound RITA, resulting in cell death that cannot be prevented by antioxidants. Together, these studies revealed multiple new insights into the complex redox chemistry of TrxR1 and ways in which it may be exploited for cancer treatment.
Publications
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(Huang M, Myers CR, Wang Y, You M.) Cancer Prev Res (Phila). 2020 Dec 10 PMID: 33303695 12/12/2020
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p38γ MAPK Is Essential for Aerobic Glycolysis and Pancreatic Tumorigenesis.
(Wang F, Qi XM, Wertz R, Mortensen M, Hagen C, Evans J, Sheinin Y, James M, Liu P, Tsai S, Thomas J, Mackinnon A, Dwinell M, Myers CR, Bartrons Bach R, Fu L, Chen G.) Cancer Res. 2020 08 15;80(16):3251-3264 PMID: 32580961 SCOPUS ID: 2-s2.0-85089787021 06/26/2020
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(Zhang Q, Cheng G, Pan J, Zielonka J, Xiong D, Myers CR, Feng L, Shin SS, Kim YH, Bui D, Hu M, Bennett B, Schmainda K, Wang Y, Kalyanaraman B, You M.) Cell Commun Signal. 2020 04 07;18(1):58 PMID: 32264893 PMCID: PMC7140380 SCOPUS ID: 2-s2.0-85083071315 04/09/2020
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Concentration of Fe(3+)-Triapine in BEAS-2B Cells.
(Antholine WE, Myers CR.) Int J Mol Sci. 2019 Jun 22;20(12) PMID: 31234559 PMCID: PMC6627071 SCOPUS ID: 2-s2.0-85068769637 06/27/2019
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Targeting lonidamine to mitochondria mitigates lung tumorigenesis and brain metastasis.
(Cheng G, Zhang Q, Pan J, Lee Y, Ouari O, Hardy M, Zielonka M, Myers CR, Zielonka J, Weh K, Chang AC, Chen G, Kresty L, Kalyanaraman B, You M.) Nat Commun. 2019 05 17;10(1):2205 PMID: 31101821 PMCID: PMC6525201 SCOPUS ID: 2-s2.0-85065824371 05/19/2019
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Treatment of Cells and Tissues with Chromate Maximizes Mitochondrial 2Fe2S EPR Signals.
(Antholine WE, Vasquez-Vivar J, Quirk BJ, Whelan HT, Wu PK, Park JI, Myers CR.) Int J Mol Sci. 2019 Mar 06;20(5) PMID: 30845710 PMCID: PMC6429069 SCOPUS ID: 2-s2.0-85062628835 03/09/2019
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(Cheng G, Zielonka M, Dranka B, Kumar SN, Myers CR, Bennett B, Garces AM, Dias Duarte Machado LG, Thiebaut D, Ouari O, Hardy M, Zielonka J, Kalyanaraman B.) J Biol Chem. 2018 06 29;293(26):10363-10380 PMID: 29739855 PMCID: PMC6028982 SCOPUS ID: 2-s2.0-85049623107 05/10/2018
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(Pan J, Lee Y, Cheng G, Zielonka J, Zhang Q, Bajzikova M, Xiong D, Tsaih SW, Hardy M, Flister M, Olsen CM, Wang Y, Vang O, Neuzil J, Myers CR, Kalyanaraman B, You M.) iScience. 2018 May 25;3:192-207 PMID: 30428319 PMCID: PMC6137433 11/15/2018
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(Yin N, Lepp A, Ji Y, Mortensen M, Hou S, Qi XM, Myers CR, Chen G.) J Biol Chem. 2017 09 08;292(36):15070-15079 PMID: 28739874 PMCID: PMC5592682 SCOPUS ID: 2-s2.0-85029228747 07/26/2017
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p38γ MAPK is required for inflammation-associated colon tumorigenesis.
(Yin N, Qi X, Tsai S, Lu Y, Basir Z, Oshima K, Thomas JP, Myers CR, Stoner G, Chen G.) Oncogene. 2016 Feb 25;35(8):1039-48 PMID: 25961922 SCOPUS ID: 2-s2.0-84959509513 05/12/2015
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(Myers CR.) Free Radic Biol Med. 2016 Feb;91:81-92 PMID: 26686468 SCOPUS ID: 2-s2.0-84951190669 12/22/2015
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(Xu J, Eriksson SE, Cebula M, Sandalova T, Hedström E, Pader I, Cheng Q, Myers CR, Antholine WE, Nagy P, Hellman U, Selivanova G, Lindqvist Y, Arnér ES.) Cell Death Dis. 2015 Jan 22;6:e1616 PMID: 25611390 PMCID: PMC4669772 SCOPUS ID: 2-s2.0-84927620824 01/23/2015