Effect of IL-8 from endothelial cells on induction of apoptosis in K562 cells. K562 cells alone (5 × 10⁴cells/mL) or human umbilical venous cells (VE cells, confluent) and K562 cells (5 × 10⁴ cells/mL) were cultured with or without LPS (500 ng/mL), IL-1 (10 U/mL), TNF- (10 U/mL), IFN-γ (200 U/mL), and M-CSF (100 ng/mL) in 24-well plates. Coculture of VE cells and K562 cells was mediated by Intercell. After 2 days, MTT assay (A) and TUNEL assay (B) were performed. Columns show the means of three independent experiments. Statistical analysis was performed using the Student’s t-test. *P < .01.