Isolation and Culture of Gastric Cancer Cells

GC-MSCs were isolated as described previously^{19 (link)}. Tumor tissues were obtained from patients who underwent radical gastrectomy and the procedure was approved by the Ethics Committee of First People’s Hospital of Lianyungang (Jiangsu, China). Briefly, fresh tumor tissues were cut into 1-mm³-sized pieces after rinsing in antibiotics to avoid contamination and placed directly into culture dishes for 30 min to improve adhesion. Thereafter, the tissue explants were floated in a growing medium of L-DMEM (Gibco, Invitrogen Corporation, Carlsbad, CA, USA) containing 15% (v/v) fetal bovine serum (FBS; Gibco). When the spindle-like cells reached subconfluence, tissue pieces were removed and adherent cells were passaged into flasks for further expansion. The homogeneous cell population at 4–5 passages was used in this study.
Human gastric cancer cell lines BGC-823 and MKN-28 were gifts from the First Affiliated Hospital of Soochow University (Jiangsu, China) and cultured in 10% (v/v) FBS-RPMI 1640 (Gibco).