[Isolation and characterization of side population cells in human gastric cancer cell line BGC-823].

Objective Isolate and characterize the side population （SP） cells with potency of stem cells from human gastric carcinoma cell line BGC-823. Methods SP and non-SP cells were sorted from BGC-823 cells by fluorescence-activated cell sorting （FACS） using Hoechst33342 staining. The tumorigenic ability of the SP cells was assessed by in vivo transplantation into non-obese diabetic/severe combined immunodeficiency mice. Results SP cells were isolated from BGC-823 cells in a proportion of 0.9% to 2.1% with respect to the whole cell population. The colony formation assay showed that the colony formation rate of the SP cells was significantly higher than that of the non-SP ceils （72.56% vs. 49.00%, P 〈 0.01 ）. The drug sensitivity test showed that the SP cells showed stronger drug resistance to 5-Fu than the non-SP cells. The in vivo transplantation of SP cells in mice showed that the tumor weight was （0. 176± 0.034）g, significantly higher thanthat of non-SP cells （0.045 ±0.046）g （P〈0.01）. Conclusions The results of this study indicate the existence of cancer stem-like SP cells in the human gastric cancer line BGC823 cells. Further characterization of this SP cell population may provide new insights for diagnosis and treatment of gastric cancer. Key words: Stomach neoplasms;  Side population ceils;  Tumor stem cells;  Flow cytometry; BGC-823 cells ;  Mice