RESUMO
Background:Recently,cancer stem cells( CSCs)has become a hot topic in cancer research. For this research topic,the primary problem is the isolation and identification of CSCs,and suspension culture is considered to be an important method for CSCs isolation. Aims:To study the isolation and identification of gastric cancer stem cells( GCSCs) and evaluate its stemness characteristics. Methods:GCSCs-like cells were enriched through spheroid formation by suspending the human gastric cancer cell lines MKN45,MGC803 and SGC7901 in serum-free medium containing epidermal growth factor( EGF)and basic fibroblast growth factor( bFGF). The third generation tumor spheres obtained were tested for the ability of colony forming;its stemness markers were identified by immunofluorescent staining,and migration and invasion capabilities were assessed by wound scratch test and Transwell assay,respectively. Growth inhibition of tumor spheres in response to cisplatin was assessed by CCK-8 assay. Results:High expressions of stem cell markers CD44 and CD54 were observed in the tumor spheres,but gastric parietal cell marker H+ /K+-ATPase was lowly expressed. Compared with parental gastric cancer cells,tumor spheres had stronger colony forming ability(P<0. 05);Furthermore,healing of wound scratch was accelerated(P<0. 05),and number of invasive cells in Transwell chamber was increased in tumor spheres(P<0. 05). The 50% inhibition concentration of cisplatin to tumor spheres increased significantly when compared with parental gastric cancer cells. Conclusions:GCSCs enriched tumor spheres can be obtained by suspension culture with serum-free medium. The tumor spheres possess enhanced capabilities of self-renewal,proliferation,migration,invasion and potential of multilineage differentiation;meanwhile,it is more resistant to chemotherapy.