Protein expression in hepatoma HepG2 cells stimulated by TGF-beta(1) was analyzed by western blotting and plasminogen activator inhibitor type 1 (PAI-1) transcriptional activity in HepG2 cells was evaluated.
Cotransfection of human or rat PAI-1 promoter luciferase constructs with expression vectors for wild-type USF-2 or USF-2 mutants in human HepG2 and rat H4IIE cells as well as in primary rat hepatocytes revealed that the effects of USF on PAI-1 expression depend on the cell type rather than the promoter context and that the USF-specific region domain of USF accounts for the observed cell type-specific effects.
We have analyzed the regulation of PAI-1 mRNA accumulation by interleukin (IL)-1, IL-6, and dexamethasone, known mediators of the acute phase response, in HepG2 cells, a highly differentiated human hepatoma cell line that produces a broad spectrum of acute phase proteins including PAI-1.
Thus, these data clearly show that LRP is the major cell-surface receptor responsible for t-PA.PAI-1 complex binding and endocytosis on human hepatoma HepG2 cells and extend the multifunctional nature of LRP as an endocytosis receptor for several structurally and functionally distinct ligands.
In the current work we have analyzed the regulation of vitronectin by transforming growth factor-beta 1 (TGF beta 1) in this hepatoma cell line by Northern hybridization, polypeptide and immunoprecipitation analyses and compared the response to another TGF beta-regulated gene, plasminogen activator inhibitor (PAI-1).