Dmem medium

LUAD cell lines (NCIH1975, NCIH1650, PC9, A549, NCIH1299) and human bronchial epithelial cell (HBE) were purchased from Shanghai Institutes for Biological Science, China. NCIH1975, NCIH1650 and HBE cells were cultured in DMEM medium (KeyGene), and PC9, A549 and NCI-H1299 cells were cultured in RPMI 1640 medium (KeyGene), supplemented with 10% fetal bovine serum. All cells were cultured at 37 °C in a humidified incubator containing 5% CO₂.

Human gastric normal epithelium cell line (GES-1) and GC cells (BGC-823, SGC-7901, and MGC-803) were purchased from Shanghai Institutes for Biological Science, China. BGC-823, SGC-7901 and MGC-803 cells were cultured in RPMI 1640 medium (KeyGene, Nanjing, China). GES-1 cells were cultured in DMEM medium (KeyGene, Nanjing, China) supplemented with 1% penicillin/streptomycin, l-glutamine, and 10% fetal bovine serum (FBS, Invitrogen, Carlsbad, CA, USA). Culture plates were incubated at 37°C in a humidified atmosphere with 5% CO².
The siRNA specifically targeting RP11-138J23.1, HuR and VAV3 was designed and synthesized by Invitrogen (Invitrogen, USA). The nucleotide sequences of all siRNAs were shown in Supplementary Table S1. The cells were transfected with siRNA using RNAiMAX (Invitrogen, USA). In addition, RP11-138J23.1 overexpression plasmid and vectors containing shRNA targeting RP11-138J23.1 was constructed and transfected with XtremeGENE HP DNA transfection reagent (Roche, Basel, Switzerland).

All cell lines (A549, H1299, H1975, PC9, H358, SPC-A1, and HBE1) were obtained from the Cell Bank of the Chinese Academy of Sciences (Shanghai, China). A549, H1299, H1975, PC9, H358 cells were cultured in RPMI 1640 medium (KeyGene, Nanjing, China), SPC-A1 and HBE1 cells were cultured in DMEM medium (KeyGene, Nanjing, China), with 100 units/mL penicillin and 100 units/mL streptomycin and 10% FBS (Thermo Fisher Scientific, MA, USA) at 37 °C in an incubator with 5% CO₂. Authentication of cells were verified by STR profiling and mycoplasma contamination of cells were tested using MycoBlue^TM mycoplasma detector (Vazyme, Nanjing, China). Transfections were performed using the Lipofectin reagent (Thermo Fisher Scientific) when cells were seeded at 50–80% confluence, according to the manufacturer’s protocol. For siRNA infection, cells were prepared to 30–50% confluence. Forty-eight hours after transfection, the cells were rinsed twice with phosphate-buffered saline and harvested for next experiments. CHX and MG132 were purchased from MedChem Express (NJ, USA).