Sh dleu1

The siRNA for DLEU1 (si-DLEU1), negative control siRNA (si-NC), miR-381-3p mimics, miR-381-3p inhibitor (miR-381-3p-in), miRNA negative control (miRNA-NC) and pcDNA-BIRC6 were commercially synthesized by GenePharma (Shanghai, China). Transient transfection was performed with 50 nM oligonucleotides using Lipofectamine 2000. Subsequent experiments were performed at 48 hrs post-transfection. Short hairpin RNA (shRNA) targeting DLEU1 (sh-DLEU1) and non-specific control (sh-NC) were synthesized by GenePharma and cloned into pSuper-retro-puromycin vectors. For a stable cell transfection, SUNE-1 cells were transfected with sh-DLEU1 or sh-NC and then selected by 0.5 μg/mL puromycin.

The human normal gastric epithelial cell line GES-1 and the GC cell lines AGS, SGC7901, MKN45, and HS-746T (all from American Type Culture Collection, Manassas, VA, USA) were cultured in a Roswell Park Memorial Institute-1640 medium (Invitrogen, Carlsbad, CA, USA) encompassing 10% fetal bovine serum (FBS), 100 U/mL penicillin, and 100 mg/mL streptomycin (Invitrogen) at 37°C with 5% CO₂.
Lipofectamine 2000 (Thermo Fisher Scientific, Waltham, Massachusetts, USA) was applied for transfection or co-transfection of short hairpin (sh)-DLEU1, overexpression (oe)-APOC1, sh-APOC1, oe-SMYD2, sh-SMYD2, and their negative controls (NCs: sh-NC and oe-NC) (all from GenePharma, Shanghai, China) in GC SGC7901 and MKN45 cells.