Fig. 5. P.A increased death receptor 4 (DR4) expression.

a Standard and b, c quantitative RT-PCR were performed to determine the expression of DR4 after a 12-h P.A treatment; d, e DR4 and its downstream effector, Caspase-8, were upregulated by P.A; f A549 cells were transfected with si-DR4 and treated with or without P.A for the indicated amount of time. Cells were collected and analyzed by flow cytometry with PI and ANNEXIN V; g Statistical results of f (three independent experiments); h, i The activation of the NF-κB pathway was inhibited by P.A treatment