p38MAPK mediates benzyl isothiocyanate-induced p21WAF1 expression in vascular smooth muscle cells via the regulation of Sp1.
It has recently been reported that the transcription factors involved in p21WAF1 activation by certain signaling factors may vary in different cell types. However, the role and importance of the signaling pathway in the transcriptional regulation of p21WAF1 on vascular smooth muscle cells (VSMC) in response to benzyl isothiocyanate (BITC) has been unclear. In this report, we demonstrate that BITC induces the p21WAF1 expression at the transcriptional level. This increase in p21WAF1 gene expression was due to p38MAPK-dependent activation of the p21WAF1 promoter by BITC. Transcription factor Sp1 binding site was identified as the cis-element for the activation of p21WAF1 promoter by BITC, as determined by deletion and mutation analysis. In addition, gel shift and supershift assays demonstrated that this BITC-responsive element binds specifically to the transcription factor Sp1. Treatment with SB203580, an inhibitor of the p38MAPK, significantly downregulated transactivation of BITC-induced Sp1. Finally, the transient expression of VSMC with dominant negative p38MAPK plasmid suppressed BITC-stimulated Sp1 activity. In conclusion, we report that the transcription factor Sp1 involved in the p38MAPK-mediated control of p21WAF1 regulation on VSMC in response to BITC has now been identified.
Moon
Sung-Kwon
SK
Department of Food and Biotechnology, Chungju National University, Chungju, Chungbuk 380-702, South Korea. sumoon66@dreamwiz.com
Choi
Yung-Hyun
YH
Kim
Cheorl-Ho
CH
Choi
Won-Seok
WS
D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005246:Feedback / Q000187:drug effects / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D017879:Isothiocyanates / Q000008:administration & dosage*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D017879:Isothiocyanates; C031403:benzyl isothiocyanate; D048051:p38 Mitogen-Activated Protein Kinases