Exp Mol Med.  2010 Dec;42(12):849-855. 10.3858/emm.2010.42.12.088.

Triptolide downregulates human GD3 synthase (hST8Sia I) gene expression in SK-MEL-2 human melanoma cells

• Kwon HY
• Kim SJ
• Kim CH
• Son SW
• Kim KS
• Lee JH
• Do SI
• Lee YC

• KMID: 1115269
• DOI: http://doi.org/10.3858/emm.2010.42.12.088

Abstract

In this study, we have shown that gene expression of human GD3 synthase (hST8Sia I) is suppressed by triptolide (TPL) in human melanoma SK-MEL-2 cells. To elucidate the mechanism underlying the downregulation of hST8Sia I gene expression in TPL-treated SK-MEL-2 cells, we characterized the TPL-inducible promoter region within the hST8Sia I gene using luciferase constructs carrying 5'-deletions of the hST8Sia I promoter. Functional analysis of the 5'-flanking region of the hST8Sia I gene demonstrated that the -1146 to -646 region, which contains putative binding sites for transcription factors c-Ets-1, CREB, AP-1 and NF-kappaB, functions as the TPL-inducible promoter of hST8Sia I in SK-MEL-2 cells. Site-directed mutagenesis and ChIP analysis indicated that the NF-kappaB binding site at -731 to -722 is crucial for TPL-induced suppression of hST8Sia I in SK-MEL-2 cells. This suggests that TPL induces down-regulation of hST8Sia I gene expression through NF-kappaB activation in human melanoma cells.

Keyword

alpha-N-acetylneuraminate alpha-2,8-sialyltransferase; gene expression regulation; melanoma; NF-kappaB; triptolide

MeSH Terms

Cell Proliferation/drug effects
Diterpenes/*pharmacology
Down-Regulation
Epoxy Compounds/pharmacology
Genes, Reporter
Humans
NF-kappa B/metabolism
Phenanthrenes/*pharmacology
Promoter Regions, Genetic
Sialyltransferases/*biosynthesis/genetics
Tumor Cells, Cultured