Figure 1

TNF-α attenuated serum starvation-induced apoptosis in Hep3B and SMMC-7721 cells. (A, B, C and D) Cell activity were detected by MTT analysis. Hep3B (A) and SMMC-7721 (B) cells were treated with or without 6 h pre-treatment of serum starvation (that is nutrient- and serum-free medium), then treated with TNF-α (0, 0.1, 1, 10, 100, 1000 ng/ml) for 24 h. Hep3B (C) and SMMC-7721 (D) cells were treated with 10 ng/ml TNF-α for 12, 24 and 48 h with 6 h pre-treatment of serum starvation. (E) Cells were cultured in medium with or without 10% FBS for 6 h, then treated with or without 10 ng/ml TNF-α for 24 h. Flow cytometry was used to test cell apoptosis rate. Data represent the mean ± SEM of three independent experiments. **P < 0.01; Student’s t-test.