TY - JOUR
T1 - Simultaneous inhibition of glutathione- and thioredoxin-dependent metabolism is necessary to potentiate 17AAG-induced cancer cell killing via oxidative stress
AU - Scarbrough, Peter M.
AU - Mapuskar, Kranti A.
AU - Mattson, David M.
AU - Gius, David
AU - Watson, Walter H.
AU - Spitz, Douglas R.
N1 - Funding Information:
The authors thank the Radiation and Free Radical Research Core Laboratory at The University of Iowa and Dr. Michel L. McCormick for his assistance in running glutathione assays. The authors also thank Drs. Melissa A. Fath, Andrean L. Simons, and Yueming Zhu, for their helpful discussions during the design of these experiments. This work was supported in part by NIH Grants R01CA133114, R01CA100045, T32CA078586, and P30CA086862 as well as the Department of Radiation Oncology at The University of Iowa.
PY - 2012/1/15
Y1 - 2012/1/15
N2 - 17-Allylamino-17-demethoxygeldanamycin (17AAG) is an experimental chemotherapeutic agent believed to form free radicals in vivo, and cancer cell resistance to 17AAG is believed to be a thiol-dependent process. Inhibitors of thiol-dependent hydroperoxide metabolism [l-buthionine-S,R-sulfoximine (BSO) and auranofin] were combined with the glucose metabolism inhibitor 2-deoxy-d-glucose (2DG) to determine if 17AAG-mediated cancer cell killing could be enhanced. When 2DG (20 mM, 24 h), BSO (1 mM, 24 h), and auranofin (500 nM, 3 h) were combined with 17AAG, cell killing was significantly enhanced in three human cancer cell lines (PC-3, SUM159, MDA-MB-231). Furthermore, the toxicity of this drug combination was significantly greater in SUM159 human breast cancer cells, relative to HMEC normal human breast epithelial cells. Increases in toxicity seen with this drug combination also correlated with increased glutathione (GSH) and thioredoxin (Trx) oxidation and depletion. Furthermore, treatment with the thiol antioxidant NAC (15 mM, 24 h) was able to significantly protect from drug-induced toxicity and ameliorate GSH oxidation, Trx oxidation, and Trx depletion. These data strongly support the hypothesis that simultaneous inhibition of GSH- and Trx-dependent metabolism is necessary to sensitize human breast and prostate cancer cells to 2DG + 17AAG-mediated killing via enhancement of thiol-dependent oxidative stress. These results suggest that simultaneous targeting of both GSH and Trx metabolism could represent an effective strategy for chemosensitization in human cancer cells.
AB - 17-Allylamino-17-demethoxygeldanamycin (17AAG) is an experimental chemotherapeutic agent believed to form free radicals in vivo, and cancer cell resistance to 17AAG is believed to be a thiol-dependent process. Inhibitors of thiol-dependent hydroperoxide metabolism [l-buthionine-S,R-sulfoximine (BSO) and auranofin] were combined with the glucose metabolism inhibitor 2-deoxy-d-glucose (2DG) to determine if 17AAG-mediated cancer cell killing could be enhanced. When 2DG (20 mM, 24 h), BSO (1 mM, 24 h), and auranofin (500 nM, 3 h) were combined with 17AAG, cell killing was significantly enhanced in three human cancer cell lines (PC-3, SUM159, MDA-MB-231). Furthermore, the toxicity of this drug combination was significantly greater in SUM159 human breast cancer cells, relative to HMEC normal human breast epithelial cells. Increases in toxicity seen with this drug combination also correlated with increased glutathione (GSH) and thioredoxin (Trx) oxidation and depletion. Furthermore, treatment with the thiol antioxidant NAC (15 mM, 24 h) was able to significantly protect from drug-induced toxicity and ameliorate GSH oxidation, Trx oxidation, and Trx depletion. These data strongly support the hypothesis that simultaneous inhibition of GSH- and Trx-dependent metabolism is necessary to sensitize human breast and prostate cancer cells to 2DG + 17AAG-mediated killing via enhancement of thiol-dependent oxidative stress. These results suggest that simultaneous targeting of both GSH and Trx metabolism could represent an effective strategy for chemosensitization in human cancer cells.
KW - 2-Deoxyglucose
KW - Auranofin
KW - Free radicals
KW - Glutathione
KW - Thioredoxin
KW - Thioredoxin reductase
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U2 - 10.1016/j.freeradbiomed.2011.10.493
DO - 10.1016/j.freeradbiomed.2011.10.493
M3 - Article
C2 - 22100505
AN - SCOPUS:84855432506
SN - 0891-5849
VL - 52
SP - 436
EP - 443
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
IS - 2
ER -