Fig. 7.

Exogenously applied EGF activates both ERK and Akt signaling cascades, which results in inhibition of caspase 3/7 activity induced by an inflammatory apoptotic challenge in HSG cells. A—C, HSG cells were exposed to exogenously applied EGF (100 ng/ml) for the indicated times. The phosphorylated (p) and total (t) EGFR (A), ERK (B), and Akt (C) levels were analyzed through immunoblotting. Quantification of the band density was performed through densitometric scanning of each band by using National Institutes of Health ImageJ software. D, HSG cells were pretreated with or without U0126 (2.5 μM) or LY294002 (2.5 μM) for 30 min. The cells then were treated with or without 100 ng/ml EGF, in the absence or presence of TNFα (50 ng/ml)/IFNγ (10 ng/ml), and were incubated for 24 h. Caspase 3/7 activity was indicated by luminescence activity, as described under Materials and Methods. Values represent the mean ± S.D. of three cultures. *, p < 0.05; **, p < 0.01, values differ significantly (t test).