Figure 3

Secreted protein acidic and rich in cysteine (SPARC) contributes to the epithelial cell death caused by transforming growth factor (TGF)-β-stimulated fibroblasts. (A) Coculture system of A549 cells and TGF-β stimulated HFL-1 cells. (B) HFL-1 cells were transfected with non-targeting control or SPARC siRNA for 24 h, starved of serum for 24 h, and then cell lysates were subjected to western blotting analysis of SPARC expression. (C) HFL-1 cells pretreated with or without TGF-β (2 ng/ml) for 16 h were washed before introduction of A549 cells. A549 cell viability was assessed following 48 h of coculture by Cell Counting kit-8. Data are expressed as means ± SE of three independent experiments. **P <0.01 versus TGF-β (−). (D) HFL-1 cells transfected with non-targeting control or SPARC siRNA were pretreated with or without TGF-β (2 ng/ml) for 16 h, and then washed before introduction of A549 cells. A549 cell viability was assessed following 48 h of coculture by Cell Counting kit-8. Data are expressed as means ± SE of three independent experiments. **P <0.01 versus non-targeting control siRNA.