Cell lines

Rat secreting pituitary adenoma cell line GH3 and human embryonic kidney cell line HEK293 were obtained and authenticated by American Type Culture Collection (ATCC, USA, Cat. No. CCL-82.1 and CCL-1573). Cells were grown in Dulbecco's modified Eagle's medium (DMEM, Gibco, Life Technologies Corporation, USA) supplemented with 15% (v/v) fetal serum albumin (FBS, Hyclone, USA) and 1% (v/v) penicillin-streptomycin-glutamine (100X, Gibco, Life Technologies, USA). Cultures were maintained in a humidified incubator (Sanyo, Japan) at 37°C with 5% CO₂. Transforming growth factor β (TGF-β, 10 ng/mL, Sigma-Aldrich, USA) was used as an inducer of cell migration and invasion.