CXCL16 overexpression sensitizes SL4 cells to TNF-α-induced cell death. (A) Viability of SL4-Cont and SL4-CXCL16 cells following TNF-α stimulation. Cells were seeded in 96-well plates (2 × 103 cells) stabilized for 1 h and stimulated by TNF-α (10 ng/ml) for 24–48 h. *P <0.05, **P <0.01. (B) Annexin V assay. Cells were seeded in 6-well plates (2 × 105 cells) and treated with TNF-α (10 ng/ml) for 0-8 h. (C) Effects of CXCL16 expression on the TNF-α-induced apoptotic pathway in SL4 cells. (D) Effects of CXCL16 expression on the TNF-α-induced NF-κB and MAPK signaling pathways in SL4 cells. β-actin was used as a normalization control. All experiments were repeated at least three times.