Snu 1

We purchased three human gastric cancer cell lines SNU-1, SNU-216, and SNU-484 from the Korean Cell Line Bank (Seoul, Korea). All cells were tested for mycoplasma contamination and were maintained in Roswell Park Memorial Institute (RPMI) medium supplemented with 10 % fetal bovine serum (FBS). The cells were cultured in a 5 % CO₂ incubator at 37 °C.

To profile the methylome and miRNome of GC, 3 GC and adjacent normal tissue samples were obtained, along with informed consent, from Pusan National University Yangsan Hospital in Korea. EpCAM+/CD44+ GC cells were isolated from the 3 GC tissues according to a previously described protocol.10 To measure the protein expression levels of miR‐1271 target genes in GC tissues, 3 paired normal tissues and GC tissues were obtained, along with informed consent, from Chungnam National University Hospital in Korea. These studies were approved by the Internal Review Board at the corresponding hospitals, and all the experiments were performed in accordance with the relevant guidelines and regulations.
Nine GC cell lines (SNU‐1, SNU‐216, SNU‐484, SNU‐601, SNU‐620, AGS, KATO III, MKN1, and MKN74) and 293T cells were purchased from Korean Cell Line Bank (Seoul, Korea). The GC cell lines and 293T cells were cultured in Roswell Park Memorial Institute (RPMI) 1640 medium and Dulbecco’s Modified Eagle’s Medium (DMEM, WELGENE, Daegu, Korea), respectively, supplemented with 10% fetal bovine serum (FBS) (HyClone, Logan, UT, USA) in a CO₂ incubator, and the cell lines were authenticated by short tandem repeat (STR) DNA profile analysis performed by the Korean Cell Line Bank facility.

The human GC cell lines, MKN45, MKN74, SNU1, SNU216, SNU668, AGS, and NCI-N87 were purchased from the Korean Cell Line Bank (KCLB) and were maintained at 37 °C in a humidified atmosphere containing 5% CO₂, in RPMI 1640 (Hyclone, South Lagan, UT, USA) supplemented with 10% fetal bovine serum (FBS) and 1% penicillin and streptomycin. Human umbilical vein endothelial cells (HUVECs) were purchased from the American Type Culture Collection (ATCC) and were cultured in endothelial cell medium (ECM; ScienCell, Carlsbad, CA, USA) at 37 °C in a humidified atmosphere containing 5% CO_2. All cell lines were routinely tested for mycoplasma contamination.