Cell Culture. SKU-1064 human skin fibroblast cells were obtained from American Type Culture Collection (ATCC, Manassas, VA), cultured in Dulbecco’s modified Eagle’s medium (1×) (DMEM) containing 10% fetal bovine serum, 1% nonessential amino acids, 100 units/mL penicillin G, 100 µg/mL streptomycin, 1.25 µg/mL amphotericin B, and 10 mM sodium pyruvate (Gibco BRL Life Technology, Grand Island, NY). Cells were incubated at 37 °C under 5% CO2 and utilized between passages 15 and 30.