Abstract
Sulforaphane is a promising agent under preclinical evaluation in many models of disease prevention. This bioactive phytochemical affects many molecular targets in cellular and animal models; however, amongst the most sensitive is Keap1, a key sensor for the adaptive stress response system regulated through the transcription factor Nrf2. Keap1 is a sulfhydryl-rich protein that represses Nrf2 signaling by facilitating the polyubiquitination of Nrf2, thereby enabling its subsequent proteasomal degradation. Interaction of sulforaphane with Keap1 disrupts this function and allows for nuclear accumulation of Nrf2 and activation of its transcriptional program. Enhanced transcription of Nrf2 target genes provokes a strong cytoprotective response that enhances resistance to carcinogenesis and other diseases mediated by exposures to electrophiles and oxidants. Clinical evaluation of sulforaphane has been largely conducted by utilizing preparations of broccoli or broccoli sprouts rich in either sulforaphane or its precursor form in plants, a stable β-thioglucose conjugate termed glucoraphanin. We have conducted a series of clinical trials in Qidong, China, a region where exposures to food- and air-borne carcinogens has been considerable, to evaluate the suitability of broccoli sprout beverages, rich in either glucoraphanin or sulforaphane or both, for their bioavailability, tolerability, and pharmacodynamic action in population-based interventions. Results from these clinical trials indicate that interventions with well characterized preparations of broccoli sprouts may enhance the detoxication of aflatoxins and air-borne toxins, which may in turn attenuate their associated health risks, including cancer, in exposed individuals.
Keywords
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Kelloff GJ, Lieberman R, Steele VE et al (2001) Agents, biomarkers, and cohorts for chemopreventive agent development in prostate cancer. Urology 57:46–51
Zhang Y, Talalay P, Cho CG, Posner GH (1992) A major inducer of anticarcinogenic protective enzymes from broccoli: isolation and elucidation of structure. Proc Natl Acad Sci USA 89:2399–2403
Nioi P, McMahon M, Itoh K, Yamamoto M, Hayes JD (2003) Identification of a novel Nrf2-regulated antioxidant response element (ARE) in the mouse NAD(P)H:quinone oxidoreductase 1 gene: reassessment of the ARE consensus sequence. Biochem J 374:337–348
Kensler TW (1997) Chemoprevention by inducers of carcinogen detoxication enzymes. Environ Health Perspect 105(Suppl 4):965–970
Dinkova-Kostova AT (2007) Chemoprotection against cancer: an idea whose time has come. Altern Ther Health Med 13:S122–S127
Zhang Y, Kensler TW, Cho CG, Posner GH, Talalay P (1994) Anticarcinogenic activities of sulforaphane and structurally related synthetic norbornyl isothiocyanates. Proc Natl Acad Sci USA 91:3147–3150
Fahey JW, Haristoy X, Dolan PM et al (2002) Sulforaphane inhibits extracellular, intracellular, and antibiotic-resistant strains of Helicobacter pylori and prevents benzo[a]pyrene-induced stomach tumors. Proc Natl Acad Sci USA 99:7610–7615
Xu C, Huang MT, Shen G et al (2006) Inhibition of 7,12-dimethylbenz(a)anthracene-induced skin tumorigenesis in C57BL/6 mice by sulforaphane is mediated by nuclear factor E2-related factor 2. Cancer Res 66:8293–8296
Juge N, Mithen RF, Traka M (2007) Molecular basis for chemoprevention by sulforaphane: a comprehensive review. Cell Mol Life Sci 64:1105–1127
Higdon JV, Delage B, Williams DE, Dashwood RH (2007) Cruciferous vegetables and human cancer risk: epidemiologic evidence and mechanistic basis. Pharmacol Res 55:224–236
Zhang Y, Tang L (2007) Discovery and development of sulforaphane as a cancer chemopreventive phytochemical. Acta Pharmacol Sin 28:1343–1354
Gamet-Payrastre L, Li P, Lumeau S et al (2000) Sulforaphane, a naturally occurring isothiocyanate, induces cell cycle arrest and apoptosis in HT29 human colon cancer cells. Cancer Res 60:1426–1433
Riboli E, Norat T (2003) Epidemiologic evidence of the protective effects of fruit and vegetables on cancer risk. Am J Clin Nutr 78:559–695
World Cancer Research Fund/American Institute for Cancer Research (2007) Food, nutrition, physical activity and the prevention of cancer: a global perspective. American Institute for Cancer Research, Washington, DC
Fahey JW, Zalcmann AT, Talalay P (2001) The chemical diversity and distribution of glucosinolates and isothiocyanates among plants. Phytochemistry 56:5–51
Shapiro TA, Fahey JW, Wade KL et al (1998) Human metabolism and excretion of cancer chemoprotective glucosinolates and isothiocyanates of cruciferous vegetables. Cancer Epidemiol Biomarkers Prev 7:1091–1100
Fahey JW, Zhang Y, Talalay P (1997) Broccoli sprouts: an exceptionally rich source of inducers of enzymes that protect against chemical carcinogens. Proc Natl Acad Sci USA 94:10367–10372
Egner PA, Chen JG, Wang JB et al (2011) Bioavailability of sulforaphane from two broccoli sprout beverages: results of a short-term, cross-over clinical trial in Qidong, China. Cancer Prev Res 4:384–395
Kensler TW, Chen JG, Egner PA et al (2005) Effects of glucosinolate-rich broccoli sprouts on urinary levels of aflatoxin-DNA adducts and phenanthrene tetraols in a randomized clinical trial in He Zuo township, Qidong, People’s Republic of China. Cancer Epidemiol Biomarkers Prev 14:2605–2613
Kensler TW, Ng D, Carmella SG et al (2012) Modulation of the metabolism of airborne pollutants by glucoraphanin-rich and sulforaphane-rich broccoli sprout beverages in Qidong, China. Carcinogenesis 33:101–107
International Agency for Research on Cancer (IARC) (2011) Agents classified by the IARC monographs, volumes 1–100. IARC Press, Lyon, France
US Department of Health and Human Services, Public Health Service, National Toxicology Program (2011) Report on Carcinogens, 12th edn
Kensler TW, Roebuck BD, Groopman JD, Wogan GN (2011) Aflatoxin: a 50-year odyssey of mechanistic and translational toxicology. Toxicol Sci 120(S1):S28–S48
Shaughnessy DT, Gangarosa LM, Schliebe B et al (2011) Inhibition of fried meat-induced colorectal DNA damage and altered systemic genotoxicity in humans by crucifera, chlorophyllin, and yogurt. PLoS One 6:e18707
Hecht SS, Carmella SG, Murphy SE (1999) Effects of watercress consumption on urinary metabolites of nicotine in smokers. Cancer Epidemiol Biomarkers Prev 8:907–913
Wang JS, Shen X, He X et al (1999) Protective alterations in phase 1 and 2 metabolism of aflatoxin B1 by oltipraz in residents of Qidong, People’s Republic of China. J Natl Cancer Inst 91:347–354
Egner PA, Wang JB, Zhu YR et al (2001) Chlorophyllin intervention reduces aflatoxin-DNA adducts in individuals at high risk for liver cancer. Proc Natl Acad Sci USA 98:14601–14606
Kensler TW, Groopman JD, Wogan GN (1996) Use of carcinogen-DNA and carcinogen-protein adduct biomarkers for cohort selection and as modifiable end points in chemoprevention trials. IARC Sci Publ 139:237–248
Ramos-Gomez M, Kwak MK, Dolan PM et al (2001) Sensitivity to carcinogenesis is increased and chemoprotective efficacy of enzyme inducers is lost in nrf2 transcription factor-deficient mice. Proc Natl Acad Sci USA 98:3410–3415
Aoki Y, Sato H, Nishimura N et al (2001) Accelerated DNA adduct formation in the lung of the Nrf2 knockout mouse exposed to diesel exhaust. Toxicol Appl Pharmacol 173:154–160
Ramos-Gomez M, Dolan PM, Itoh K, Yamamoto M, Kensler TW (2003) Interactive effects of nrf2 genotype and oltipraz on benzo[a]pyrene-DNA adducts and tumor yield in mice. Carcinogenesis 24:461–467
Yates MS, Kwak MK, Egner PA et al (2006) Potent protection against aflatoxin-induced tumorigenesis through induction of Nrf2-regulated pathways by the triterpenoid 1-[2-cyano-3-, 12-dioxooleana-1, 9(11)-dien-28-oyl]imidazole. Cancer Res 66:2488–2494
Hayes JD, McMahon M (2009) NRF2 and KEAP1 mutations: permanent activation of an adaptive response in cancer. Trends Biochem Sci 34:176–188
Taguchi K, Motohashi H, Yamamoto M (2011) Molecular mechanisms of the keap1-Nrf2 pathway in stress response and cancer evolution. Genes Cells 16:123–140
Tong KI, Katoh Y, Kusunoki H, Itoh K, Tanaka T, Yamamoto M (2006) Keap1 recruits Neh2 through binding to ETGE and DLG motifs: characterization of the two-site molecular recognition model. Mol Cell Biol 26:2887–2900
Zhang DD, Hannink M (2003) Distinct cysteine residues in Keap1 are required for Keap1-dependent ubiquitination of Nrf2 and for the stabilization of Nrf2 by chemopreventive agents and oxidative stress. Mol Cell Biol 23:8137–8151
Holland R, Hawkins AD, Eggler AL et al (2008) Prospective type 1 and type 2 disulfides of Keap1 protein. Chem Res Toxicol 21:2015–2060
Malhotra D, Portales-Casamar E, Singh A et al (2010) Global mapping of binding sites for Nrf2 identifies novel targets in cell survival response through ChIPSeq profiling and network analysis. Nucleic Acids Res 38:5718–5734
Kensler TW, Wakabayashi N, Biswal S (2007) Cell survival responses to environmental stresses via the Keap1-Nrf2-ARE pathway. Annu Rev Pharmacol Toxicol 47:89–116
Wakabayashi N, Shin S, Slocum SL, Agoston ES, Wakabayashi J, Kwak MK, Misra V, Biswal S, Yamamoto M, Kensler TW (2010) Regulation of notch1 signaling by nrf2: implications for tissue regeneration. Sci Signal 3(130):ra52
Chen W, Sun Z, Wang XJ et al (2009) Direct interaction between Nrf2 and p21(Cip1/WAF1) upregulates the Nrf2-mediated antioxidant response. Mol Cell 34:663–673
Komatsu M, Kurokawa H, Waguri S et al (2010) The selective autophagy substrate p62 activates the stress responsive transcription factor Nrf2 through inactivation of Keap1. Nat Cell Biol 12:213–223
Lau A, Wang XJ, Zhao F, Villeneuve NF, Wu T, Jiang T, Sun Z, White E, Zhang DD (2010) A noncanonical mechanism of activation by autophagy deficiency: direct interaction between Keap1 and p62. Mol Cell Biol 30:3275–3285
Shin S, Wakabayashi N, Misra V et al (2007) NRF2 modulates aryl hydrocarbon receptor signaling: influence on adipogenesis. Mol Cell Biol 27:7188–7197
Li W, Khor TO, Xu C et al (2008) Activation of Nrf2-antioxidant signaling attenuates NFKappaB-inflammatory response and elicits apoptosis. Biochem Pharmacol 76:1485–1489
Song MY, Kim EK, Moon WS et al (2009) Sulforaphane protects against cytokine- and streptozotocin-induced beta-cell damage by suppressing the NF-kappaB pathway. Toxicol Appl Pharmacol 235:57–67
Wakabayashi N, Slocum SL, Skoko JJ, Shin S, Kensler TW (2010) When NRF2 talks, who’s listening? Antioxid Redox Signal 13:1649–1663
Zhang Y (2000) Role of glutathione in the accumulation of anticarcinogenic isothiocyanates and their glutathione conjugates by murine hepatoma cells. Carcinogenesis 21:1175–1182
Dinkova-Kostova AT, Holtzclaw WD, Cole RN et al (2002) Direct evidence that sulfhydryl groups of Keap1 are the sensors regulating induction of phase 2 enzymes that protect against carcinogens and oxidants. Proc Natl Acad Sci USA 99:11908–11913
Hong F, Sekhar KR, Freeman ML, Liebler DC (2005) Identification of sensor cysteines in human Keap1 modified by the cancer chemopreventive agent sulforaphane. Chem Res Toxicol 18:1917–1926
Hu C, Eggler AL, Mesecar AD, van Breemen RB (2011) Modification of keap1 cysteine residues by sulforaphane. Chem Res Toxicol 24:515–521
Kobayashi M, Li L, Iwamoto N et al (2009) The antioxidant defense system Keap1-Nrf2 comprises a multiple sensing mechanism for responding to a wide range of chemical compounds. Mol Cell Biol 29:493–502
McMahon M, Lamont DJ, Beattie KA, Hayes JD (2010) Keap1 perceives stress via three sensors for the endogenous signaling molecules nitric oxide, zinc and alkenals. Proc Natl Acad Sci USA 107:18838–18843
Kwak MK, Kensler TW (2010) Targeting Nrf2 signaling for cancer chemoprevention. Toxicol Appl Pharmacol 244:66–76
Thimmulappa RK, Mai KH, Srisuma S et al (2002) Identification of Nrf2-regulated genes induced by the chemopreventive agent sulforaphane by oligonucleotide array. Cancer Res 62:5196–5203
Hu R, Xu C, Shen G et al (2006) Gene expression profiles induced by cancer chemopreventive isothiocyanate sulforaphane in the liver of C57BL/6J mice and C57BL6J/Nrf2(−/−) mice. Cancer Lett 243:170–192
Kwak MK, Wakabayashi N, Itoh K et al (2003) Modulation of gene expression by cancer chemopreventive dithiolethiones through the Keap1-Nrf2 pathway. Identification of novel gene clusters for cell survival. J Biol Chem 278:8135–8145
Yates MS, Tran QT, Dolan PM et al (2009) Genetic versus chemoprotective activation of Nrf2 signaling: overlapping yet distinct gene expression profiles between Keap1 knockout and triterpenoid-treated mice. Carcinogenesis 30:1024–1031
Cornblatt BS, Ye L, Dinkova-Kostova AT et al (2007) Preclinical and clinical evaluation of sulforaphane for chemoprevention in the breast. Carcinogenesis 28:1485–1490
Clarke JD, Hsu A, Williams DE et al (2011) Metabolism and distribution of sulforaphane in Nrf2 knockout and wild-type mice. Pharm Res 28:3171–3179
Devling TW, Lindsay CD, McLellan LI et al (2005) Utility of siRNA against Keap1 as a strategy to stimulate a cancer chemopreventive phenotype. Proc Natl Acad Sci USA 102:7280–7285
Jeong WS, Keum YS, Chen C et al (2005) Differential expression and stability of endogenous nuclear factor E2-related factor 2 (Nrf2) by natural chemopreventive compounds. J Biochem Mol Biol 38:167–176
Agyeman AS, Chaerkaedy R, Shaw PG et al (2012) Transcriptomic and proteomic profiling of KEAP1 disrupted and sulforaphane-treated human breast epithelial cells reveals common expression profiles. Breast Cancer Res Treat 132:175–187
Shapiro TA, Fahey JW, Dinkova-Kostova AT et al (2006) Safety, tolerance and metabolism of broccoli sprout glucosinolates and isothiocyanates: a clinical phase I study. Nutr Cancer 55:53–62
Ye L, Dinkova-Kostova AT, Wade KL et al (2002) Quantitative determination of dithiolcarbamates in human plasma, serum, erythrocytes and urine: pharmacokinetics of broccoli sprout isothiocyanates in humans. Clin Chim Acta 316:43–53
Fahey JW, Talalay P, Kensler TW (2012) Notes from the field: “green” chemoprevention as frugal medicine. Cancer Prev Res 5:179–188
Acknowledgments
This work has been supported by USPHS grants P01 ES006052, R01 CA93780, R01 CA94076, Breast SPORE P50 CA088843, Center grant ES003819, Department of Defense W81XWH-08-1-0176, and the Prevent Cancer Foundation.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2012 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Kensler, T.W. et al. (2012). Keap1–Nrf2 Signaling: A Target for Cancer Prevention by Sulforaphane. In: Pezzuto, J., Suh, N. (eds) Natural Products in Cancer Prevention and Therapy. Topics in Current Chemistry, vol 329. Springer, Berlin, Heidelberg. https://doi.org/10.1007/128_2012_339
Download citation
DOI: https://doi.org/10.1007/128_2012_339
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-34574-6
Online ISBN: 978-3-642-34575-3
eBook Packages: Chemistry and Materials ScienceChemistry and Material Science (R0)