Keratinocyte serum

The gastric adenocarcinoma cell lines AGS, SNU1, MKN28, MKN45, and STKM2 were used in the study. The immortalized nonneoplastic gastric (GES1) and esophageal (EPC2) cell lines were included as normal controls. AGS and SNU1 cells were purchased from American Type Culture Collection (ATCC, Manassas, VA). MKN28 and MKN45 cells were obtained from the Riken Cell Bank (Tsukuba, Japan). EPC2 cells were kindly provided by Dr. Anil Rustgi (University of Pennsylvania, Philadelphia, PA). GES1 cells were kindly provided by Dr. Dawit Kidane-Mulat (University of Texas at Austin, Austin, TX). AGS cells were cultured in Ham's F12 media (GIBCO, Carlsbad, CA) supplemented with 5% fetal bovine serum (FBS, Invitrogen Life Technologies, Carlsbad, CA) and 1% penicillin/streptomycin (P/S) (GIBCO). MKN28, MKN45, and GES1 cells were cultured in Roswell Park memorial institute (RPMI) medium (GIBCO) supplemented with 10% FBS and 1% P/S. EPC2 cells were cultured in Keratinocyte serum-free medium supplemented with recombinant epidermal growth factor and bovine pituitary extract (GIBCO). All cell lines were ascertained to conform to the original in vitro morphological characteristics and were authenticated using short tandem repeat (STR) profiling (Genetica DNA Laboratories, Burlington, NC). All cell lines reported here have been tested and had shown to be free of mycoplasma (R&D Systems, Minneapolis, MN).

The human NPC cell lines 5–8F, 6–10B, CNE1 and CNE2 as well as the NP69 human immortalized nasopharyngeal epithelial cell line were obtained from the American Type Culture Collection (Manassas, VA, USA). The 5–8F cell line has a high metastatic potential, while that of the 6–10B cell line is low. The CNE1 cell line is well-differentiated, while differentiation of CNE2 cells is low. The NPC cell lines were cultured in RPMI-1640 (Gibco-BRL, Invitrogen Life Technologies, Inc., Carlsbad, CA, USA) supplemented with 10% heat-inactivated fetal bovine serum (FBS; Gibco-BRL) and 0.01% penicillin and streptomycin (Gibco-BRL). NP69 cells were cultured in keratinocyte serum-free medium (Gibco-BRL) without any supplementation. All cells were cultured at 37°C in a humidified incubator in an atmosphere containing 5% CO₂.