Tumorigenesis of isolated gastric cancer cells

Objective To develop an effective method for the isolation and identification of gastric cancer stem cells and to investigate the possibility of establishing stable gastric cancer stem cell line. Methods Flow cytometry was performed to analyse and sort CD44 positive and CD133 positive fraction of gastric cancer cell lines MKN28,MKN45,SGC7901 and cells from surgical samples. Different cell fractions and cell spheres cultured in serum-free media were subcutaneously implanted into nude mice to compare the tumorigenesis of potential gastric cancer stem cells. Results One hundred CD44 positive and CD133 positive cells from the four cell lines failed to form tumors in nude mice..The tumorigenic potential of 10 000 cells was similar to their paternal cell lines..Sphere cells cultured in serum-free medium exhibited a stronger tumorigenic potential..Conclusion Compared with the selection by the cell surface maker CD44 and CD133, serum-free medium cultured sphere cells may serve as a better approach to isolate gastric tumor initiating cells.