TY - JOUR
T1 - Inhibition of AP-1 and MAPK signaling and activation of Nrf2/ARE pathway by quercitrin
AU - Ding, Min
AU - Zhao, Jinshun
AU - Bowman, Linda
AU - Lu, Yongju
AU - Shi, Xianglin
PY - 2010/1
Y1 - 2010/1
N2 - Quercitrin, glycosylated form of flavonoid compounds, is widely distributed in nature. Extensive studies have demonstrated that quercitrin exhibits strong antioxidant and anti-carcinogenic activities. However, the molecular mechanism is poorly understood. The present study examines the effects of quercitrin on tumor promotion in mouse JB6 cells, a validated model for screening cancer chemopreventive agents and elucidating the molecular mechanisms. Quercitrin blocked TPA-induced neoplastic transformation in JB6 P+ cells. Pretreatment of JB6 cells with quercitrin down-regulated transactivation of AP-1 and NF-κkB induced by UVB or TPA. In the skin of AP-1-luciferase transgenic mice, topical treatment of the mouse with quercitrin markedly blocked the TPA-induced AP-1 transactivation. Further studies indicated that these inhibitory actions appear to be mediated through the inhibition of MAPKs phosphorylation, including ERKs, p38 kinase, and JNKs. In addition, quercitrin stimulated the activation of NF-E2-related factor (Nrf2) and GST AREluciferase activity. Comet assays showed that quercitrin could block DNA damage induced by UVB. To our knowledge, these results provide the first evidence that quercitrin contributes to the inhibition of neoplastic transformation by blocking activation of the MAPK pathway and stimulation of cellular protection signaling. Moreover, to our knowledge, these findings provide the first molecular basis for the anticarcinogenic action of quercitrin.
AB - Quercitrin, glycosylated form of flavonoid compounds, is widely distributed in nature. Extensive studies have demonstrated that quercitrin exhibits strong antioxidant and anti-carcinogenic activities. However, the molecular mechanism is poorly understood. The present study examines the effects of quercitrin on tumor promotion in mouse JB6 cells, a validated model for screening cancer chemopreventive agents and elucidating the molecular mechanisms. Quercitrin blocked TPA-induced neoplastic transformation in JB6 P+ cells. Pretreatment of JB6 cells with quercitrin down-regulated transactivation of AP-1 and NF-κkB induced by UVB or TPA. In the skin of AP-1-luciferase transgenic mice, topical treatment of the mouse with quercitrin markedly blocked the TPA-induced AP-1 transactivation. Further studies indicated that these inhibitory actions appear to be mediated through the inhibition of MAPKs phosphorylation, including ERKs, p38 kinase, and JNKs. In addition, quercitrin stimulated the activation of NF-E2-related factor (Nrf2) and GST AREluciferase activity. Comet assays showed that quercitrin could block DNA damage induced by UVB. To our knowledge, these results provide the first evidence that quercitrin contributes to the inhibition of neoplastic transformation by blocking activation of the MAPK pathway and stimulation of cellular protection signaling. Moreover, to our knowledge, these findings provide the first molecular basis for the anticarcinogenic action of quercitrin.
KW - Antioxidant
KW - Cancer prevention
KW - Cell signaling
KW - Flavonoids
UR - http://www.scopus.com/inward/record.url?scp=74549159301&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=74549159301&partnerID=8YFLogxK
U2 - 10.3892/ijo-00000475
DO - 10.3892/ijo-00000475
M3 - Article
C2 - 19956833
AN - SCOPUS:74549159301
SN - 1019-6439
VL - 36
SP - 59
EP - 67
JO - International Journal of Oncology
JF - International Journal of Oncology
IS - 1
ER -