MLK3 is a direct target of biochanin A, which plays a role in solar UV-induced COX-2 expression in human keratinocytes.
Solar UV (sUV) is an important environmental carcinogen. Recent studies have shown that sUV is associated with numerous human skin disorders, such as wrinkle formation and inflammation. In this study, we found that the isoflavone, biochanin A, inhibited the expression of sUV-induced COX-2, which is a well-characterized sUV-induced enzyme, in both human HaCaT keratinocytes and JB6 P+ mouse skin epidermal cells. Several studies have demonstrated the beneficial effects of biochanin A. However, its direct molecular target is unknown. We found that biochanin A inhibited sUV-induced phosphorylation of MKK4/JNK/c-Jun and MKK3/6/p38/MSK1. Mixed-lineage kinase 3 (MLK3) is an upstream kinase of MKK4 and MKK3/6. Thus, we evaluated the effect of biochanin A on MLK3. We found that sUV-induced MLK3 phosphorylation was not affected, whereas MLK3 kinase activity was significantly suppressed by biochanin A. Furthermore, direct binding of biochanin A in the MLK3 ATP-binding pocket was detected using pull-down assays. Computer modeling supported our observation that MLK3 is a novel target of biochanin A. These results suggest that biochanin A exerts chemopreventive effects by suppressing sUV-induced COX-2 expression mediated through MLK3 inhibition.
The Hormel Institute, University of Minnesota, 801 16th Avenue NE, Austin, MN, 55912, USA; Advanced Institutes of Convergence Technology, Seoul National University, Suwon, 443-270, Republic of Korea; WCU Biomodulation Major, Department of Agricultural Biotechnology and Center for Food and Bioconvergence, Seoul National University, Seoul, 151-921, Republic of Korea.
Tae-Gyu
TG
Lim
Jong-Eun
JE
Kim
Sung Keun
SK
Jung
Yan
Y
Li
Ann M
AM
Bode
Jun-Seong
JS
Park
Myeong Hun
MH
Yeom
Zigang
Z
Dong
Ki Won
KW
Lee
D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D048055:Mitogen-Activated Protein Kinase 8 / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011487:Protein Conformation; D015398:Signal Transduction / Q000187:drug effects; D012867:Skin / Q000166:cytology / Q000187:drug effects; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014466:Ultraviolet Rays; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11; D000099151:MAP Kinase Kinase Kinase 7
D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D019833:Genistein; D020930:MAP Kinase Kinase Kinases; D048055:Mitogen-Activated Protein Kinase 8; D018808:Transcription Factor AP-1; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11; D000099151:MAP Kinase Kinase Kinase 7; C496540:PTGS2 protein, human; C004541:biochanin A
Biochanin A; Cyclooxygenase-2; Mixed-lineage kinase 3; Solar UV