Mechanism of action of isothiocyanates: the induction of ARE-regulated genes is associated with activation of ERK and JNK and the phosphorylation and nuclear translocation of Nrf2.
The up-regulation of phase II detoxifying and stress-responsive genes is believed to play an important role in cancer prevention, and many natural compounds have been shown to be potent inducers of these genes. Previous studies showed that the antioxidant responsive element (ARE), found in these genes, can be bound by the transcription factor Nrf2, and is responsive to the activation by chemopreventive compounds and by oxidative stress. In the present study, we investigated the roles of extracellular signal-regulated kinase (ERK) and c-Jun-NH(2)-kinase (JNK) in the regulation of phenethyl isothiocyanate (PEITC)-induced and Nrf2-dependent ARE activity and ARE-driven heme oxygenase-1 (HO-1) gene expression in PC-3 cells. ARE activity and HO-1 expression were strongly increased after treatment with PEITC. PEITC also increased the phosphorylation of ERK1/2 and JNK1/2 and caused release of Nrf2 from sequestration by Keap1, and its subsequent translocation into the nucleus. Importantly, Nrf2 was also translocated into the nucleus after transfection with ERK or JNK and that these activated ERK and JNK colocalized with Nrf2 in the nucleus. Activation of ERK and JNK signaling also resulted in the elevation of ARE activity and HO-1 expression. Importantly, PEITC-induced ARE activity was attenuated by inhibition of ERK and JNK signaling. In vitro kinase assays showed that both ERK2 and JNK1 could directly phosphorylate glutathione S-transferase-Nrf2 protein. Taken together, these results strongly suggest a model in which PEITC treatment of PC-3 cells activates ERK and JNK, which, in turn, phosphorylate Nrf2 and induce its translocation to the nucleus. Nuclear Nrf2 activates ARE elements and induces expression of stress-responsive genes, including HO-1.
Xu
Changjiang
C
Department of Pharmaceutics, Ernest-Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, 08854, USA.
Yuan
Xiaoling
X
Pan
Zui
Z
Shen
Guoxiang
G
Kim
Jung-Hwan
JH
Yu
Siwang
S
Khor
Tin Oo
TO
Li
Wenge
W
Ma
Jianjie
J
Kong
Ah-Ng Tony
AN
D021581:Active Transport, Cell Nucleus; D000975:Antioxidants / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D051547:Heme Oxygenase-1 / Q000187:drug effects / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000187:drug effects / Q000378:metabolism; D017879:Isothiocyanates / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D000072019:Kelch-Like ECH-Associated Protein 1; D008297:Male; D048055:Mitogen-Activated Protein Kinase 8 / Q000187:drug effects / Q000378:metabolism; D048056:Mitogen-Activated Protein Kinase 9 / Q000187:drug effects / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology; D020218:Response Elements / Q000187:drug effects / Q000235:genetics; D014407:Tumor Cells, Cultured
D000975:Antioxidants; D047908:Intracellular Signaling Peptides and Proteins; D017879:Isothiocyanates; C431364:KEAP1 protein, human; D000072019:Kelch-Like ECH-Associated Protein 1; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; C058305:phenethyl isothiocyanate; D051547:Heme Oxygenase-1; D048056:Mitogen-Activated Protein Kinase 9; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048055:Mitogen-Activated Protein Kinase 8