Terrein inhibits keratinocyte proliferation via ERK inactivation and G2/M cell cycle arrest.
Terrein, a fungal metabolite, has been recently shown to have a strong antiproliferative effect on skin equivalents. In the present study, we further investigated the effects of terrein on the possible signalling pathways involved in the growth inhibition of human epidermal keratinocytes by examining the regulations of extracellular signal-regulated protein kinase (ERK) and of the Akt pathway by terrein. It was observed that ERK was inactivated by terrein and that keratinocyte proliferation was inhibited, whereas Akt was unaffected. The inhibition of the ERK pathway by U0126 (a specific ERK inhibitor) also had a dose-dependent antiproliferative effect on human keratinocytes. These results indicate that ERK inhibition is involved in keratinocyte growth inhibition by terrein. Moreover, flow cytometric analysis showed that terrein inhibits DNA synthesis, as evidenced by a reduction in the S phase and an increase in the G2/M phase of the cell cycle. Thus, we next examined changes in the expressions of G2/M cell cycle-related proteins. Terrein was found to downregulate cyclin B1 and Cdc2 without Cdc2 phosphorylation, but upregulated p27(KIP1) (p27), a known inhibitor of cyclin-dependent kinase. These results suggest that terrein reduces human keratinocyte proliferation by inhibiting ERK and by decreasing the expressions of cyclin B1 and Cdc2 complex.
Kim
Dong-Seok
DS
Department of Biochemistry, College of Medicine, Chung-Ang University, Republic of Korea.
Lee
Hyun-Kyung
HK
Park
Seo-Hyoung
SH
Lee
Sangku
S
Ryoo
In-Ja
IJ
Kim
Won-Gon
WG
Yoo
Ick-Dong
ID
Na
Jung-Im
JI
Kwon
Sun-Bang
SB
Park
Kyoung-Chan
KC
D002070:Butadienes / Q000494:pharmacology; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects* / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019926:Cyclin B / Q000378:metabolism; D056744:Cyclin B1; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation; D011498:Protein Precursors / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
D002070:Butadienes; C534699:CCNB1 protein, human; D019926:Cyclin B; D056744:Cyclin B1; D003517:Cyclopentanes; D009570:Nitriles; D011498:Protein Precursors; C113580:U 0126; D050760:Cyclin-Dependent Kinase Inhibitor p27; C439087:terrein; C032253:involucrin; D016203:CDC2 Protein Kinase; D048049:Extracellular Signal-Regulated MAP Kinases