Abstract
Sulforaphane is an isothiocyanate derived from cruciferous vegetables that has been linked to decreased risk of certain cancers. Although the role of sulforaphane in the induction of the transcription factor Nrf2 has been studied extensively, there is also evidence that inhibition of the transcription factor activator protein-1 (AP-1) may contribute to the chemopreventive properties of this compound. In this study, we show for the first time that sulforaphane is effective at reducing the multiplicity and tumor burden of UVB-induced squamous cell carcinoma in a mouse model using cotreatment with the compound and the carcinogen. We also show that sulforaphane pretreatment is able to reduce the activity of AP-1 luciferase in the skin of transgenic mice after UVB. Chromatin immunoprecipitation analysis verified that a main constituent of the AP-1 dimer, cFos, is inhibited from binding to the AP-1 DNA binding site by sulforaphane. Electrophoretic mobility shift assay analysis of nuclear proteins also shows that sulforaphane and diamide, both known to react with cysteine amino acids, are effective at inhibiting AP-1 from binding to its response element. Using truncated recombinant cFos and cJun, we show that mutation of critical cysteines in the DNA-binding domain of these proteins (Cys154 in cFos and Cys272 in cJun) results in loss of sensitivity to both sulforaphane and diamide in electrophoretic mobility shift assay analysis. Together, these data indicate that inhibition of AP-1 activity may be an important molecular mechanism in chemoprevention of squamous cell carcinoma by sulforaphane.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 7103-7110 |
| Number of pages | 8 |
| Journal | Cancer Research |
| Volume | 69 |
| Issue number | 17 |
| DOIs | |
| State | Published - Sep 1 2009 |
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ASJC Scopus subject areas
- Cancer Research
- Oncology
Cite this
Inhibition of activator protein-1 by sulforaphane involves interaction with cysteine in the cFos DNA-binding domain : Implications for chemoprevention of UVB-induced skin cancer. / Dickinson, Sally E; Melton, Tania F.; Olson, Erik R.; Zhang, Jian; Saboda, Kathylynn; Bowden, G. Timothy.
In: Cancer Research, Vol. 69, No. 17, 01.09.2009, p. 7103-7110.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Inhibition of activator protein-1 by sulforaphane involves interaction with cysteine in the cFos DNA-binding domain
T2 - Implications for chemoprevention of UVB-induced skin cancer
AU - Dickinson, Sally E
AU - Melton, Tania F.
AU - Olson, Erik R.
AU - Zhang, Jian
AU - Saboda, Kathylynn
AU - Bowden, G. Timothy
PY - 2009/9/1
Y1 - 2009/9/1
N2 - Sulforaphane is an isothiocyanate derived from cruciferous vegetables that has been linked to decreased risk of certain cancers. Although the role of sulforaphane in the induction of the transcription factor Nrf2 has been studied extensively, there is also evidence that inhibition of the transcription factor activator protein-1 (AP-1) may contribute to the chemopreventive properties of this compound. In this study, we show for the first time that sulforaphane is effective at reducing the multiplicity and tumor burden of UVB-induced squamous cell carcinoma in a mouse model using cotreatment with the compound and the carcinogen. We also show that sulforaphane pretreatment is able to reduce the activity of AP-1 luciferase in the skin of transgenic mice after UVB. Chromatin immunoprecipitation analysis verified that a main constituent of the AP-1 dimer, cFos, is inhibited from binding to the AP-1 DNA binding site by sulforaphane. Electrophoretic mobility shift assay analysis of nuclear proteins also shows that sulforaphane and diamide, both known to react with cysteine amino acids, are effective at inhibiting AP-1 from binding to its response element. Using truncated recombinant cFos and cJun, we show that mutation of critical cysteines in the DNA-binding domain of these proteins (Cys154 in cFos and Cys272 in cJun) results in loss of sensitivity to both sulforaphane and diamide in electrophoretic mobility shift assay analysis. Together, these data indicate that inhibition of AP-1 activity may be an important molecular mechanism in chemoprevention of squamous cell carcinoma by sulforaphane.
AB - Sulforaphane is an isothiocyanate derived from cruciferous vegetables that has been linked to decreased risk of certain cancers. Although the role of sulforaphane in the induction of the transcription factor Nrf2 has been studied extensively, there is also evidence that inhibition of the transcription factor activator protein-1 (AP-1) may contribute to the chemopreventive properties of this compound. In this study, we show for the first time that sulforaphane is effective at reducing the multiplicity and tumor burden of UVB-induced squamous cell carcinoma in a mouse model using cotreatment with the compound and the carcinogen. We also show that sulforaphane pretreatment is able to reduce the activity of AP-1 luciferase in the skin of transgenic mice after UVB. Chromatin immunoprecipitation analysis verified that a main constituent of the AP-1 dimer, cFos, is inhibited from binding to the AP-1 DNA binding site by sulforaphane. Electrophoretic mobility shift assay analysis of nuclear proteins also shows that sulforaphane and diamide, both known to react with cysteine amino acids, are effective at inhibiting AP-1 from binding to its response element. Using truncated recombinant cFos and cJun, we show that mutation of critical cysteines in the DNA-binding domain of these proteins (Cys154 in cFos and Cys272 in cJun) results in loss of sensitivity to both sulforaphane and diamide in electrophoretic mobility shift assay analysis. Together, these data indicate that inhibition of AP-1 activity may be an important molecular mechanism in chemoprevention of squamous cell carcinoma by sulforaphane.
UR - http://www.scopus.com/inward/record.url?scp=70149093188&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=70149093188&partnerID=8YFLogxK
U2 - 10.1158/0008-5472.CAN-09-0770
DO - 10.1158/0008-5472.CAN-09-0770
M3 - Article
C2 - 19671797
AN - SCOPUS:70149093188
VL - 69
SP - 7103
EP - 7110
JO - Journal of Cancer Research
JF - Journal of Cancer Research
SN - 0099-7013
IS - 17
ER -