The pre-neoplastic murine skin epidermal JB6 Cl 41-5a promotion sensitive (JB6 P+) cells and CaCo2 cells, a human colorectal adenocarcinoma cell line, were purchased from the American Type Cell Culture Collection (ATCC, Rockville, MD, USA). Cells were cultured in Eagle’s Minimal Essential Medium (EMEM), supplemented with 15% or 5% heat-inactivated fetal bovine serum (FBS) (CaCo2 cells or JB6 P + cells, respectively), 2mM L-glutamine, 1x MEM Non-Essential Amino Acid Solution, 0.1 mg/mL streptomycin, 0.1 U/L penicillin, and 1mM Na-pyruvate.
For the JB6 P + cells, the 12-O-tetradecanoylphorbol-13-acetate (TPA) was used as a tumor promoter and dissolved in dimethyl sulfoxide (20 ng/mL). All cell culture materials were purchased from Sigma-Aldrich (St. Louis, MO, USA). The cells were grown in a humidified atmosphere at 37 °C with 5% CO2.
For the JB6 P + cells, the 12-O-tetradecanoylphorbol-13-acetate (TPA) was used as a tumor promoter and dissolved in dimethyl sulfoxide (20 ng/mL). All cell culture materials were purchased from Sigma-Aldrich (St. Louis, MO, USA). The cells were grown in a humidified atmosphere at 37 °C with 5% CO2.