Exp Mol Med.  2001 Sep;33(3):117-123.

Cell-type specific regulation of thrombospondin-1 expression and its promoter activity by regulatory agents

• Kim SA
• Kang JH
• Cho IH
• Bae SW
• Hong KJ

Abstract

Thrombospondin-1 (TSP-1), a multifunctional protein that is able to function as a negative regulator of solid tumor progression and angiogenesis, is normally present at a very low level but rapidly elevated in pathological tissues. To understand the cellular regulation of TSP-1 expression, the mode of it's expression in Hep3B, SK-HEP-1, and porcine aortic endothelial (PAE) cells was examined in the presence of all-trans retinoic acid (ATRA), interleukin-6 (IL-6), interferon-gamma (IFN-gamma), or phorbol 12-myristate 13-acetate (PMA). ATRA or IL-6 induced a dose-dependent increase of TSP-1 protein and mRNA levels in PAE cells, while they negatively regulated TSP-1 expression in the Hep3B and SK-HEP-1 cells. In contrast, PMA showed just the opposite effects on the TSP-1 expression in the same cells. IFN-gamma had little effect on TSP-1 level in Hep3B and PAE cells. The TSP-1 expression in SK-HEP-1 cells by these agents showed a close resemblance to that of liver cells rather than that of the endothelial cell line. Possible TSP-1 promoter-mediated responses by ATRA, IL-6, IFN-gamma, or PMA in Hep3B and PAE cells examined with luciferase activity of TSP-LUC reporter plasmid showed that levels of TSP-1 promoter activity were lower than that of the expressed TSP-1 protein and mRNA levels. Transfection of c-Jun and/or RARalpha expression vectors into Hep3B and PAE cells resulted in the enhanced TSP-1 promoter activity as well as the increments of of its protein and mRNA level. These results suggest that regulatory agents-induced TSP-1 expression may be attributed to mRNA stability and/or translational activation in concert with transcriptional activation and TSP-1 expression may be independently controlled via each signal pathway stimulated by PMA or ATRA.

Keyword

All-trans retinoic acid; IFN-g; IL-6; PMA; TSP-1; Hep3B; PAE cell

MeSH Terms

Animal
Cell Line
Endothelium, Vascular/cytology/drug effects/metabolism
*Gene Expression Regulation/drug effects
Genes, Reporter
Genes, jun
Human
Immunoblotting
Interferon Type II/pharmacology
Interleukin-6/pharmacology
*Promoter Regions (Genetics)
Proto-Oncogene Proteins c-jun/genetics/metabolism
Receptors, Retinoic Acid/genetics/metabolism
Recombinant Fusion Proteins/metabolism
Tetradecanoylphorbol Acetate/pharmacology
Thrombospondin 1/*genetics/metabolism
Transcription, Genetic
Tretinoin/pharmacology