TABLE 1

Effects of transfection of varying amounts of PLC-γ sense or dominant negative mutant DNA on both NF-κB activity and I-κBα levels in intestinal Caco-2 monolayers

Intestinal cells stably transfected with varying amounts of PLC-γ sense DNA (1, 2, 3, or 5 μg) were exposed to oxidant (H₂O₂, 0.5 mM). In separate studies, cells transfected with varying amounts of a PLC-γ dominant negative DNA, namely, PLCz (1, 2, 3, or 5 μg), were treated with EGF (10 ng/ml) before exposure to oxidant. Wild-type (WT) cells, which are not transfected, are also shown. Monolayer NF-κB (p65) activity and I-κBα levels were assessed as described under Materials and Methods.

Treatment	NF-κB Activity (OD, 450 nm)	I-κBα Levels (% Maximum)
Vehicle	0.09 ± 0.01	100 ± 2.0
H₂O₂ [WT]	1.55 ± 0.25^*	14 ± 7.0^*
H₂O₂ [1-μg sense PLC-γ DNA]	1.28 ± 0.08^*^‡	29 ± 0.6^*^‡
H₂O₂ [2-μg sense PLC-γ DNA]	0.75 ± 0.09^*^†^‡	47 ± 3.0^*^†^‡
H₂O₂ [3-μg sense PLC-γ DNA]	0.27 ± 0.05^*^†	84 ± 4.0^*^†
H₂O₂ [5-μg sense PLC-γ DNA]	0.28 ± 0.09^*^†	82 ± 6.0^*^†
EGF (10 ng/ml) + H₂O₂ [WT]	0.12 ± 0.02^†	95 ± 0.5^†
EGF (10 ng/ml) + H₂O₂ [1-μg dominant neg. PLC-γ DNA]	0.23 ± 0.06^*^†^‡	80 ± 1.0^*^†^‡
EGF (10 ng/ml) + H₂O₂ [2-μg dominant neg. PLC-γ DNA]	0.89 ± 0.02^*^†^‡	56 ± 2.0^*^†^‡
EGF (10 ng/ml) + H₂O₂ [3-μg dominant neg. PLC-γ DNA]	1.39 ± 0.25^*^†	22 ± 5.0^*^†
EGF (10 ng/ml) + H₂O₂ [5-μg dominant neg. PLC-γ DNA]	1.35 ± 0.10^*^†	23 ± 3.0^*^†

Values are means ± S.E.M. n = 4 to 6 per group.
↵* p < 0.05 compared with the vehicle.
↵† p < 0.05 compared with H₂O₂ in WT cells.
↵‡ p < 0.05 compared with corresponding cells transfected with 3 μg of sense PLC-γ DNA and exposed to H₂O₂ or cells transfected with 3 μg of PLC-γ dominant mutant DNA and treated with EGF and then H₂O₂.