Fig. 5. Effects of silica on the expression of transcriptional factors in RLE-6TN cells. Snail (A and E), Slug (A and D), Twist (A and F), ZEB-1 (A and B) and ZEB-2 (A and C) were measured by western blot of the RLE-6TN cells cultured with or without silica (12.5–100 μg ml^–1) for 48 h. *P < 0.05 vs. control.