FIGURE 8.

Involvement of NF-κB in SVCT-2 expression and ascorbate uptake. A, cultures were preincubated with PDTC (100 μm) or sulfasalazine (100 μm) for 10 min. Then, cells were incubated with SNAP (100 μm) (B) or l-arginine (2 mm) (C) either in the presence or absence of the mentioned compounds for 80 min. Next, samples were prepared for Western blotting. Results represent the mean ± S.E.M. of independent experiments, all carried out in duplicates. In B: control (n = 9), SNAP (n = 9), SNAP + Sulfa (n = 3), Sulfa (n = 3), SNAP + PDTC (n = 3), PDTC (n = 3). In C, control (n = 3), l-arginine (n = 3), l-Arg + Sulfa (n = 3), Sulfa (n = 3), l-Arg + PDTC (n = 3), PDTC (n = 3). Cultures were also preincubated with PDTC (100 μm) or sulfasalazine (100 μm) for 10 min. Then, cells were incubated with SNAP (100 μm) (D) or l-arginine (2 mm) (E) either in presence or absence of the mentioned compounds for an additional 10 min. Next, cells were pulsed with [¹⁴C]ascorbate (0.1 μCi/ml) for 40 min, lysed with 5% TCA (w/v), and the radioactivity was measured. Results represent the mean ± S.E.M. of different and independent experiments, all carried out in triplicates. In D, SNAP (n = 17), SNAP + PDTC (n = 3), PDTC (n = 3), SNAP + Sulfa (n = 3), Sulfa (n = 3). In E, l-arginine (n = 7), l-Arg + PDTC (n = 3), PDTC (n = 6), l-Arg + Sulfa (n = 3), Sulfa (n = 3). ***, p < 0.001 (relative to control); **, p < 0.01 (relative to control). CT, control.