Human OSCC cell lines, including SCC-4, Tca8113 and SCC-9, and human normal oral keratinocyte NOK cell line were purchased from the Cell Bank of the Chinese Academy of Sciences (Shanghai, China). These cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM; Hyclone, Logan, UT, USA) containing 10% fetal bovine serum (FBS; Sigma-Aldrich, St. Louis, MO, USA), 100 U/mL penicillin and 100 μg/mL streptomycin at 37°C in a humidified incubator with 5% CO2.
The specific small interference RNA (siRNA) targeting HCP5 (si-HCP5), miR-140-5p mimics and the scrambled oligonucleotides (NC) were obtained from GenePharma Co., Ltd (Shanghai, China). The full length sequence of human HCP5 cDNA was amplified by PCR, and then subcloned into the vector pcDNA3.1 (Invitrogen, Carlsbad, CA, USA). Cells grown at 70–80% confluence were transfected with the oligonucleotides and vectors using Lipofectamine 2000 (Invitrogen). After 48 hrs, the cells were collected for further experiments.
The specific small interference RNA (siRNA) targeting HCP5 (si-HCP5), miR-140-5p mimics and the scrambled oligonucleotides (NC) were obtained from GenePharma Co., Ltd (Shanghai, China). The full length sequence of human HCP5 cDNA was amplified by PCR, and then subcloned into the vector pcDNA3.1 (Invitrogen, Carlsbad, CA, USA). Cells grown at 70–80% confluence were transfected with the oligonucleotides and vectors using Lipofectamine 2000 (Invitrogen). After 48 hrs, the cells were collected for further experiments.