__NODE__ in culture medium causes little or no change in trans activation of reporter gene with a DNA endogenous promoter ( 106 142 ) containing a mutant IR1 response element ( G 65A G 64A C 56T C 55T ) from the __SP__ __NODE__ gene in HepG2 cells that involves __SP__ __NODE__ protein in HepG2 cells and __SP__ __NODE__ protein in HepG2 cells .