Fibroblast cells were purchased from American Type Culture Collection (USA) and cultured in Iscove’s modified Dulbecco’s medium (Welgene, Korea) supplemented with antibiotics (Gibco, USA) and 10% fetal bovine serum (FBS; Gibco, USA). Immortalized human keratinocytes (HaCaT) were cultured in Dulbecco’s modified Eagle’s medium (Welgene, Korea) supplemented with antibiotics (Gibco, USA) and 10% FBS (Gibco, USA). Human epidermal keratinocyte-neonatal (HEKn) was purchased from Gibco (USA) and cultured in EpiLife medium (Gibco, USA). All conditions are maintained at 37C with 5% CO2 atmosphere.