Il 24

Human small intestinal epithelial cell line (FHs74Int), (American Type Culture Collection (ATCC), Manassas, VA, USA) was cultured in Hybri-Care Medium (ATCC) supplemented with 30 ng/mL EGF, 10% heat-inactivated fetal bovine serum (FBS) (Invitrogen, Carlsbad, CA, USA) and 1% penicillin and streptomycin mixture (Life Technologies) under standard cell culture conditions (37 °C, humidified, 5% CO₂/95% air environment).
For real time RT-PCRs the cells were seeded into 6 or 96 well plates at a density of 10⁵ or 10⁴ cells/well and treated with IL-1β (100 ng/mL), TNF-α (10 ng/mL), TGF-β (0.5 nM), or IL-17 (100 ng/mL) on 6 well plates (n = 6 well/treatment group), or with IL-24 (0.1 ng/mL) and H₂O₂ (1000 µM) on 96 well plates (n = 5 well/treatment group) for 24 h, respectively.
For MTT and LDH assays the cells were seeded into 96-well plates at a density of 10⁴ cells/well (n = 5 well/treatment group) and treated with IL-24 (0.1 ng/mL) and H₂O₂ (200, 400, 600, 800 or 1000 µM) (Sigma-Aldrich) for 24 h.
The cells were seeded into 6 well plates at a density of 3 × 10⁵ cells/well (n = 3 well/treatment group) for the Annexin V apoptosis assay, and treated with IL-24 (0.1 ng/mL) and H₂O₂ (1000 µM) for 48 h.
Vehicle treated cells served as controls in all experiments.