Expression data from gastric cancer cell line HGC27 after knockdown of SNAIL

SNAIL, which is a key factor in EMT, has high expression levels in the gastric spheres. To investigate SNAIL-regulated genes, we knocked down this gene in the gastric cancer cell line HGC-27 and compared the gene expression of these cells with those of the parental cells by microarray. The lentivirus package system: pMDLg/pRRE (Addgene, plasmid #12251), pRSV-Rev (Addgene, plasmid #12253) and pMD2.G (Addgene, plasmid #12259) together with the shRNA plasmid targeting the human SNAIL gene as well as the control vector: pLKO.1puro (Addgene, plasmid #8453) were co-transfected into 293T cells by Lipofectamine 3000 (Invitrogen). SNAIL-targeting short-hairpin RNA (MISSION shRNA) duplex (A: 5-TGCTCCACAAGCACCAAGAGTC-3; B: 5-CCACTCAGATGTCAAGAAGTAC-3) was purchased from Sigma-Aldrich Co. LCC. (St. Louis, MO, USA). About 48 to 72 hours later, virus supernatant was collected for concentration. For shRNA knockdown, HGC27 cells were seeded onto 6-well plates and infected with optimal virus concentrations supplemented with 6 µg/mL Polybrene (Sigma, St. Louis, MO, USA), then incubated for 12 hours before replacing with fresh medium. Cells were then selected by puromycin (INVIVOGEN, Japan) at the concentration of 1.8 µg/ml for 2 weeks.