Syndecan-1 mRNA and protein levels in the empty vector and syndecan-1 transfected HepG2 and Hep3B cell lines. (A) Transcripts coding for the extracellular domain (ED) and the cytoplasmic domain (CD) of syndecan-1 were elevated in the full-length transfectants, while the expression of the CD only was increased in the truncated transfectants, whereas that of the ectodomain-coding transcript remained unchanged; (B) High amounts of full-length (ectodomain-containing) syndecan-1 protein were detected on the surface of both full-length and truncated syndecan-1 transfectants by immunofluorescence using an ectodomain-specific antibody; (C) ELISA confirmed elevation of full-length syndecan-1 in both transfectants; (D) A comparison with the empty vector-transfected cells, shows that the abundance of AO4B08-reactive (internal 2-O-sulfated/6-O-sulfated) HS epitopes are decreased, whereas the amount of HS4C3-reactive (highly sulfated, 3-O-sulfated) epitopes are increased in both Hep3B cell lines containing syndecan-1 constructs. Data points represent the mean ± standard deviation (SD), n = 3; * p < 0.05; ** p < 0.01; *** p < 0.001 versus the empty vector control. Representative images are at 600× magnification (scale bar 30 μm) and 400× magnification (scale bar 50 μm).