Figure 4

SSW smoke stimulates stress response proteins and cell survival. SSW stimulated an increase in immediate early stress-response proteins as assayed by immunoblotting analysis. (A) cIL-8 was stimulated in a dose-dependent manner. (B) PKB/Akt was phosphorylated/activated by 5 minutes. (C-E) The levels of grp78 (C), p53 (D), and p21 (E) were all increased upon stimulation with SSW smoke. GAPDH was used as a marker for levels of sample loading. Because the supernatant does not contain GAPDH, we verified equal loading for cIL-8 by using coomassie blue staining of identical samples. (F) Cells were treated for 18 hours, allowed to recover in fresh medium for 24 hours, treated again for 18 hours and then counted using a Coulter counter. The number of cells after SSW treatment was comparable to that of the control, suggesting that cells survived well even though they were cultured in the presence of SSW smoke. For immunoblotting analysis, cells were treated and lysates separated using SDS-PAGE. Each figure is a representative of at least 2 experiments. PT = Pretreatment; N = 3 indicates 3 samples per experimental group.