Role of reactive oxygen species and Cr(VI) in Ras-mediated signal transduction

Suwei Wang; Stephen S. Leonard; Jianping Ye; Ning Gao; Liying Wang; Xianglin Shi

doi:10.1023/B:MCBI.0000007268.42733.53

Role of reactive oxygen species and Cr(VI) in Ras-mediated signal transduction

Suwei Wang, Stephen S. Leonard, Jianping Ye, Ning Gao, Liying Wang, Xianglin Shi

Toxicology and Cancer Biology

Research output: Contribution to journal › Review article › peer-review

32 Scopus citations

Abstract

Previous studies have shown that a constitutively active isoform of Ras is able to produce superoxide radical (O₂^-). The present study investigate the mechanisms by which O₂^- radical mediates signals from Ras protein to the nucleus, leading to cellular responses such as apoptosis in Cr(VI) -stimulated cells. Two human prostate tumor cell lines, Ras(+), which overexpresses Ras, and Ras(-), which has a normal Ras level, were utilized. Compared to Ras(-) cells, Ras(+) cells exhibited higher susceptibility to apoptosis induced by Cr(VI). Catalase, sodium formate, and deferoxamine inhibited Cr(VI)-induced apoptosis. Similar differences were observed in both cellular DNA damage and the activation of p53 protein. The differences in Cr(VI)-induced cell responses in Ras(+) and Ras(-) cells were due to differences in the generation of free radicals between these two cells. ESR spin trapping measurements showed that Ras(+) cells generated more hydroxyl radical (•OH), O₂^- radical, and Cr(V) than Ras(-) cells following Cr(VI) stimulation. The generation of the reactive oxygen species (ROS) can be abolished by the addition of superoxide dismutase (SOD) or if the experiment were carried out in an argon atmosphere. Catalase inhibited spin adduct signals but was much less potent than SOD. The mechanism of ROS generation in Cr(VI)-stimulated Ras(+) cells involves the reduction of molecular oxygen to O₂^- radical by a flavoenzyme-containing NADPH oxidase complex as shown by oxygen consumption and diphenylene iodonium (DPI) inhibition. Results shown above support the following conclusions: (a) Ras protein mediates O₂^- radical generation through reduction of molecular oxygen by NADPH oxidase in Cr(VI)-stimulated cells. (b) The O₂^- radical and Cr(VI) produce other reactive species, including H₂O₂, •OH radical, and Cr(V) through O₂^- dismutation and Haber-Weiss type of reactions. (c) Among these reactive species, •OH radical is responsible for the further transduction of signals from Ras to the nucleus, leading to various cell responses.

Original language	English
Pages (from-to)	119-127
Number of pages	9
Journal	Molecular and Cellular Biochemistry
Volume	255
Issue number	1-2
DOIs	https://doi.org/10.1023/B:MCBI.0000007268.42733.53
State	Published - Jan 2004

Bibliographical note

Funding Information:
Molecular oxygen is the original source of ROS generation in Ras(+) cells under Cr(VI) stimulation. Reduction of molecular oxygen and generation of O2·– was demonstrated by elimination of ESR signals under an argon atmosphere. The major reductase involved is the flavoprotein-containing NADPH oxidase complex rather than the mitochondrial electron transfer chain. This conclusion was supported by the inhibition of ROS generation by DPI, a highly selective flavoprotein inhibitor. Rotenone, an inhibitor of mitochondrial electron transport chain, only exhibited slight inhibition.

Keywords

Apoptosis
Cr(VI)
DNA damage
NADPH oxidase
Ras oncoprotein
Reactive oxygen species
p53 activation

ASJC Scopus subject areas

Molecular Biology
Clinical Biochemistry
Cell Biology

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10.1023/B:MCBI.0000007268.42733.53

Cite this

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title = "Role of reactive oxygen species and Cr(VI) in Ras-mediated signal transduction",

abstract = "Previous studies have shown that a constitutively active isoform of Ras is able to produce superoxide radical (O2-). The present study investigate the mechanisms by which O2- radical mediates signals from Ras protein to the nucleus, leading to cellular responses such as apoptosis in Cr(VI) -stimulated cells. Two human prostate tumor cell lines, Ras(+), which overexpresses Ras, and Ras(-), which has a normal Ras level, were utilized. Compared to Ras(-) cells, Ras(+) cells exhibited higher susceptibility to apoptosis induced by Cr(VI). Catalase, sodium formate, and deferoxamine inhibited Cr(VI)-induced apoptosis. Similar differences were observed in both cellular DNA damage and the activation of p53 protein. The differences in Cr(VI)-induced cell responses in Ras(+) and Ras(-) cells were due to differences in the generation of free radicals between these two cells. ESR spin trapping measurements showed that Ras(+) cells generated more hydroxyl radical (•OH), O2- radical, and Cr(V) than Ras(-) cells following Cr(VI) stimulation. The generation of the reactive oxygen species (ROS) can be abolished by the addition of superoxide dismutase (SOD) or if the experiment were carried out in an argon atmosphere. Catalase inhibited spin adduct signals but was much less potent than SOD. The mechanism of ROS generation in Cr(VI)-stimulated Ras(+) cells involves the reduction of molecular oxygen to O2- radical by a flavoenzyme-containing NADPH oxidase complex as shown by oxygen consumption and diphenylene iodonium (DPI) inhibition. Results shown above support the following conclusions: (a) Ras protein mediates O2- radical generation through reduction of molecular oxygen by NADPH oxidase in Cr(VI)-stimulated cells. (b) The O2- radical and Cr(VI) produce other reactive species, including H2O2, •OH radical, and Cr(V) through O2- dismutation and Haber-Weiss type of reactions. (c) Among these reactive species, •OH radical is responsible for the further transduction of signals from Ras to the nucleus, leading to various cell responses.",

keywords = "Apoptosis, Cr(VI), DNA damage, NADPH oxidase, Ras oncoprotein, Reactive oxygen species, p53 activation",

author = "Suwei Wang and Leonard, {Stephen S.} and Jianping Ye and Ning Gao and Liying Wang and Xianglin Shi",

note = "Funding Information: Molecular oxygen is the original source of ROS generation in Ras(+) cells under Cr(VI) stimulation. Reduction of molecular oxygen and generation of O2·– was demonstrated by elimination of ESR signals under an argon atmosphere. The major reductase involved is the flavoprotein-containing NADPH oxidase complex rather than the mitochondrial electron transfer chain. This conclusion was supported by the inhibition of ROS generation by DPI, a highly selective flavoprotein inhibitor. Rotenone, an inhibitor of mitochondrial electron transport chain, only exhibited slight inhibition.",

year = "2004",

month = jan,

doi = "10.1023/B:MCBI.0000007268.42733.53",

language = "English",

volume = "255",

pages = "119--127",

number = "1-2",

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T1 - Role of reactive oxygen species and Cr(VI) in Ras-mediated signal transduction

AU - Wang, Suwei

AU - Leonard, Stephen S.

AU - Ye, Jianping

AU - Gao, Ning

AU - Wang, Liying

AU - Shi, Xianglin

N1 - Funding Information: Molecular oxygen is the original source of ROS generation in Ras(+) cells under Cr(VI) stimulation. Reduction of molecular oxygen and generation of O2·– was demonstrated by elimination of ESR signals under an argon atmosphere. The major reductase involved is the flavoprotein-containing NADPH oxidase complex rather than the mitochondrial electron transfer chain. This conclusion was supported by the inhibition of ROS generation by DPI, a highly selective flavoprotein inhibitor. Rotenone, an inhibitor of mitochondrial electron transport chain, only exhibited slight inhibition.

PY - 2004/1

Y1 - 2004/1

N2 - Previous studies have shown that a constitutively active isoform of Ras is able to produce superoxide radical (O2-). The present study investigate the mechanisms by which O2- radical mediates signals from Ras protein to the nucleus, leading to cellular responses such as apoptosis in Cr(VI) -stimulated cells. Two human prostate tumor cell lines, Ras(+), which overexpresses Ras, and Ras(-), which has a normal Ras level, were utilized. Compared to Ras(-) cells, Ras(+) cells exhibited higher susceptibility to apoptosis induced by Cr(VI). Catalase, sodium formate, and deferoxamine inhibited Cr(VI)-induced apoptosis. Similar differences were observed in both cellular DNA damage and the activation of p53 protein. The differences in Cr(VI)-induced cell responses in Ras(+) and Ras(-) cells were due to differences in the generation of free radicals between these two cells. ESR spin trapping measurements showed that Ras(+) cells generated more hydroxyl radical (•OH), O2- radical, and Cr(V) than Ras(-) cells following Cr(VI) stimulation. The generation of the reactive oxygen species (ROS) can be abolished by the addition of superoxide dismutase (SOD) or if the experiment were carried out in an argon atmosphere. Catalase inhibited spin adduct signals but was much less potent than SOD. The mechanism of ROS generation in Cr(VI)-stimulated Ras(+) cells involves the reduction of molecular oxygen to O2- radical by a flavoenzyme-containing NADPH oxidase complex as shown by oxygen consumption and diphenylene iodonium (DPI) inhibition. Results shown above support the following conclusions: (a) Ras protein mediates O2- radical generation through reduction of molecular oxygen by NADPH oxidase in Cr(VI)-stimulated cells. (b) The O2- radical and Cr(VI) produce other reactive species, including H2O2, •OH radical, and Cr(V) through O2- dismutation and Haber-Weiss type of reactions. (c) Among these reactive species, •OH radical is responsible for the further transduction of signals from Ras to the nucleus, leading to various cell responses.

AB - Previous studies have shown that a constitutively active isoform of Ras is able to produce superoxide radical (O2-). The present study investigate the mechanisms by which O2- radical mediates signals from Ras protein to the nucleus, leading to cellular responses such as apoptosis in Cr(VI) -stimulated cells. Two human prostate tumor cell lines, Ras(+), which overexpresses Ras, and Ras(-), which has a normal Ras level, were utilized. Compared to Ras(-) cells, Ras(+) cells exhibited higher susceptibility to apoptosis induced by Cr(VI). Catalase, sodium formate, and deferoxamine inhibited Cr(VI)-induced apoptosis. Similar differences were observed in both cellular DNA damage and the activation of p53 protein. The differences in Cr(VI)-induced cell responses in Ras(+) and Ras(-) cells were due to differences in the generation of free radicals between these two cells. ESR spin trapping measurements showed that Ras(+) cells generated more hydroxyl radical (•OH), O2- radical, and Cr(V) than Ras(-) cells following Cr(VI) stimulation. The generation of the reactive oxygen species (ROS) can be abolished by the addition of superoxide dismutase (SOD) or if the experiment were carried out in an argon atmosphere. Catalase inhibited spin adduct signals but was much less potent than SOD. The mechanism of ROS generation in Cr(VI)-stimulated Ras(+) cells involves the reduction of molecular oxygen to O2- radical by a flavoenzyme-containing NADPH oxidase complex as shown by oxygen consumption and diphenylene iodonium (DPI) inhibition. Results shown above support the following conclusions: (a) Ras protein mediates O2- radical generation through reduction of molecular oxygen by NADPH oxidase in Cr(VI)-stimulated cells. (b) The O2- radical and Cr(VI) produce other reactive species, including H2O2, •OH radical, and Cr(V) through O2- dismutation and Haber-Weiss type of reactions. (c) Among these reactive species, •OH radical is responsible for the further transduction of signals from Ras to the nucleus, leading to various cell responses.

KW - Apoptosis

KW - Cr(VI)

KW - DNA damage

KW - NADPH oxidase

KW - Ras oncoprotein

KW - Reactive oxygen species

KW - p53 activation

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DO - 10.1023/B:MCBI.0000007268.42733.53

M3 - Review article

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AN - SCOPUS:0742289404

SN - 0300-8177

VL - 255

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JO - Molecular and Cellular Biochemistry

JF - Molecular and Cellular Biochemistry

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ER -

Role of reactive oxygen species and Cr(VI) in Ras-mediated signal transduction

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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