Chemical genetics analysis of an aniline mustard anticancer agent reveals complex I of the electron transport chain as a target
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Fedeles_etal_JBC_2011_submitted-manuscript.pdf
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Author(s)
Fedeles, Bogdan I.
Zhu, Angela W.
Young, Kellie S.
Hillier, Shawn M.
Proffitt, Kyle D.
Essigmann, John M.
Croy, Robert G.
Date Issued
August 2011
Journal
Journal of Biological Chemistry
Publisher
American Society for Biochemistry and Molecular Biology (ASBMB)
Citation
Fedeles, B. I. et al. “Chemical Genetics Analysis of an Aniline Mustard Anticancer Agent Reveals Complex I of the Electron Transport Chain as a Target.” Journal of Biological Chemistry 286.39 (2011): 33910-33920. Web. 17 Feb. 2012. © 2011 The American Society for Biochemistry and Molecular Biology, Inc.
Version
Author's final manuscript
Abstract
The antitumor agent 11β (CAS 865070-37-7), consisting of a DNA-damaging aniline mustard linked to an androgen receptor (AR) ligand, is known to form covalent DNA adducts and to induce apoptosis potently in AR-positive prostate cancer cells in vitro; it also strongly prevents growth of LNCaP xenografts in mice. The present study describes the unexpectedly strong activity of 11β against the AR-negative HeLa cells, both in cell culture and tumor xenografts, and uncovers a new mechanism of action that likely explains this activity. Cellular fractionation experiments indicated that mitochondria are the major intracellular sink for 11β; flow cytometry studies showed that 11β exposure rapidly induced oxidative stress, mitochondria being an important source of reactive oxygen species (ROS). Additionally, 11β inhibited oxygen consumption both in intact HeLa cells and in isolated mitochondria. Specifically, 11β blocked uncoupled oxygen consumption when mitochondria were incubated with complex I substrates, but it had no effect on oxygen consumption driven by substrates acting downstream of complex I in the mitochondrial electron transport chain. Moreover, 11β enhanced ROS generation in isolated mitochondria, suggesting that complex I inhibition is responsible for ROS production. At the cellular level, the presence of antioxidants (N-acetylcysteine or vitamin E) significantly reduced the toxicity of 11β, implicating ROS production as an important contributor to cytotoxicity. Collectively, our findings establish complex I inhibition and ROS generation as a new mechanism of action for 11β, which supplements conventional DNA adduct formation to promote cancer cell death.
Description
Supplementary information is available at the Journal of Biological Chemistry website.
MIT Department
Massachusetts Institute of Technology. Department of Biological Engineering
Massachusetts Institute of Technology. Department of Chemistry
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Creative Commons Attribution-Noncommercial-Share Alike 3.0
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DOI of Published Version
https://doi.org/10.1074/jbc.M111.278390
