Exp Mol Med.  2005 Jun;37(3):186-192.

Curcumin inhibits the expression of COX-2 in UVB-irradiated human keratinocytes (HaCaT) by inhibiting activation of AP-1: p38 MAP kinase and JNK as potential upstream targets

• Cho JW
• Park K
• Kweon GR
• Jang BC
• Baek WK
• Suh MH
• Kim CW
• Lee KS
• Suh SI

Abstract

Ultraviolet B (UVB) irradiation of skin induces an acute inflammation. Cyclooxygenase-2 (COX-2) protein plays key roles in acute inflammation in UVB-irradiated keratinocyte cell line HaCaT. Recently, curcumin has been regarded as a promising anti-inflammatory agent due to its ability to inhibit COX-2 expression. However, it remains largely unknown whether curcumin inhibits the UVB-induced COX-2 expression in HaCaT cells. This study was undertaken to clarify the effect of curcumin on the expression of COX-2 in UVB- irradiated HaCaT cells and further determined the molecular mechanisms associated with this process. In this study, we have found that the expression of COX-2 mRNA and protein were up-regulated in UVB-irradiated HaCaT cells in a dose- and time-dependent manner. Interestingly, treatment with curcumin strongly inhibited COX-2 mRNA and protein expressions in UVB-irradiated HaCaT cells. Notably, there was effective inhibition by curcumin on UVB-induced activations of p38 MAPK and JNK in HaCaT cells. The DNA binding activity of AP-1 transcription factor was also markedly decreased with curcumin treatment in UVB-irradiated HaCaT cells. These results collectively suggest that curcumin may inhibit COX- 2 expression by suppressing p38 MAPK and JNK activities in UVB-irradiated HaCaT cells. We propose that curcumin may be applied as an effective and novel sunscreen drug for the protection of photoinflammation.

Keyword

COX-2; curcumin; HaCaT; MAPK; UVB

MeSH Terms

Curcumin/*pharmacology
Enzyme Activation/drug effects/radiation effects
Enzyme Inhibitors/pharmacology
Humans
JNK Mitogen-Activated Protein Kinases/antagonists & inhibitors/*metabolism
Keratinocytes/cytology/*drug effects/*radiation effects
Prostaglandin-Endoperoxide Synthase/*metabolism
Research Support, Non-U.S. Gov't
Transcription Factor AP-1/*metabolism
Ultraviolet Rays
p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors/*metabolism