Cell culture of human keratinocytes and epithelial cells

The human keratinocyte cell line hTert/KER-CT (ATCC^®, CRL4048) was purchased from LGC Standards GmbH (Wesel, Germany) and cultured as described [44 (link)]. The cells were maintained at 37 °C and 5% CO₂ in basal Keratinocyte Growth Medium 2 (KGM2, PromoCell, Heidelberg, Germany) supplemented with 4 µL/mL bovine pituitary extract, 0.125 ng/mL epidermal growth factor (recombinant human), 5 µg/mL insulin (recombinant human), 0.33 µg/mL hydrocortisone, 0.39 µg/mL epinephrine, 10 µg/mL transferrin (recombinant human), 0.05 mM CaCl₂ (all from PromoCell) and 30 µg/mL gentamicin sulphate (Serva, Heidelberg, Germany). For experiments under high calcium conditions, the cells were grown in KGM2 with 2 mM CaCl₂. The human epithelial cell line T84 was maintained at 37 °C in a humidified incubator under 5% CO₂ in Dulbecco’s modified Eagle’s medium (DMEM)/F-12 medium (1:1), supplemented with 20% heat-inactivated fetal bovine serum, 50 U/mL streptomycin and 50 U/mL penicillin.