Norbert Nass1, Saadettin Sel2, Atanas Ignatov3, Albert Roessner4, Thomas Kalinski4. 1. Otto von Guericke University Magdeburg, Department of Pathology, Leipziger Str. 44, House 28, D-39120 Magdeburg, Germany. Electronic address: norbert.nass@med.ovgu.de. 2. University of Heidelberg, Department of Ophthalmology, Im Neuenheimer Feld 400, D-69120 Heidelberg, Germany. 3. Otto von Guericke University Magdeburg, Department of Obstetrics and Gynecology, Gerhart-Hauptmann Str. 35, 39108 Magdeburg, Germany. 4. Otto von Guericke University Magdeburg, Department of Pathology, Leipziger Str. 44, House 28, D-39120 Magdeburg, Germany.
Abstract
BACKGROUND: Acquired tamoxifen resistance is a significant problem in estrogen receptor positive breast cancer. In a cellular model, tamoxifen resistance was associated with increased sensitivity towards toxic dicarbonyls and reduced free sulfhydryl group content. We here analyzed the role of oxidative stress and glyoxalase I activity on dicarbonyl resistance and the significance of glyoxalase I expression for survival. METHODS: Reactive oxygen species were determined by 2,7-dihydrochlorofluorescein diacetate. Inhibitors for NADPH-oxidase (diphenyleneiodonium), p38 MAPK (SB203580) and ERK1/2 (UO126) were applied to investigate interactions of these signaling molecules. N-acetyl cysteine was used to evaluate the effect of oxidative stress on cell viability, which was assessed by the resazurin assay. Gene expression was analyzed by real time qRT-PCR. Glyoxalase activity was inhibited by the specific inhibitor CS-0683 and siRNA. The relevance of glyoxalase 1 mRNA abundance on survival of breast cancer patients was evaluated by the KM-plotter web interface. RESULTS: α-Oxo-aldehydes caused an immediate increase in reactive oxygen species where the tamoxifen resistant cell line (TamR) responded at lower concentrations than the MCF-7 parental cell line. Inhibitor studies placed ROS production by NADPH-oxidase downstream of p38 MAPK. The antioxidant N-acetyl cysteine (NAC) increased survival, whereas glyoxalase (GLO1) inhibition increased dicarbonyl toxicity. GLO1 mRNA abundance was correlated with unfavorable prognosis of breast cancer patients. CONCLUSIONS: Dicarbonyl toxicity was mediated by oxidative stress and GLO1 activity determines aldehyde toxicity in tamoxifen resistant cells. GENERAL SIGNIFICANCE: Glyoxalases might be predictive biomarkers for tamoxifen resistance and a putative target for the treatment of tamoxifen resistant breast cancer patients.
BACKGROUND: Acquired tamoxifen resistance is a significant problem in estrogen receptor positive breast cancer. In a cellular model, tamoxifen resistance was associated with increased sensitivity towards toxic dicarbonyls and reduced free sulfhydryl group content. We here analyzed the role of oxidative stress and glyoxalase I activity on dicarbonyl resistance and the significance of glyoxalase I expression for survival. METHODS:Reactive oxygen species were determined by 2,7-dihydrochlorofluorescein diacetate. Inhibitors for NADPH-oxidase (diphenyleneiodonium), p38 MAPK (SB203580) and ERK1/2 (UO126) were applied to investigate interactions of these signaling molecules. N-acetyl cysteine was used to evaluate the effect of oxidative stress on cell viability, which was assessed by the resazurin assay. Gene expression was analyzed by real time qRT-PCR. Glyoxalase activity was inhibited by the specific inhibitor CS-0683 and siRNA. The relevance of glyoxalase 1 mRNA abundance on survival of breast cancerpatients was evaluated by the KM-plotter web interface. RESULTS: α-Oxo-aldehydes caused an immediate increase in reactive oxygen species where the tamoxifen resistant cell line (TamR) responded at lower concentrations than the MCF-7 parental cell line. Inhibitor studies placed ROS production by NADPH-oxidase downstream of p38 MAPK. The antioxidant N-acetyl cysteine (NAC) increased survival, whereas glyoxalase (GLO1) inhibition increased dicarbonyltoxicity. GLO1 mRNA abundance was correlated with unfavorable prognosis of breast cancerpatients. CONCLUSIONS:Dicarbonyltoxicity was mediated by oxidative stress and GLO1 activity determines aldehydetoxicity in tamoxifen resistant cells. GENERAL SIGNIFICANCE: Glyoxalases might be predictive biomarkers for tamoxifen resistance and a putative target for the treatment of tamoxifen resistant breast cancerpatients.
Authors: Martin Porsch; Esra Özdemir; Martin Wisniewski; Sebastian Graf; Fabian Bull; Katrin Hoffmann; Atanas Ignatov; Johannes Haybaeck; Ivo Grosse; Thomas Kalinski; Norbert Nass Journal: RNA Biol Date: 2019-03-05 Impact factor: 4.652
Authors: Antje Hutschenreuther; Marina Bigl; Nasr Y A Hemdan; Tewodros Debebe; Frank Gaunitz; Gerd Birkenmeier Journal: Int J Mol Sci Date: 2016-12-18 Impact factor: 5.923
Authors: Yueming Zhu; Xianghui Zou; Angela E Dean; Joseph O' Brien; Yucheng Gao; Elizabeth L Tran; Seong-Hoon Park; Guoxiang Liu; Matthew B Kieffer; Haiyan Jiang; Melissa E Stauffer; Robert Hart; Songhua Quan; Karla J F Satchell; Nobuo Horikoshi; Marcelo Bonini; David Gius Journal: Nat Commun Date: 2019-06-03 Impact factor: 14.919