Characterization of sphere-forming cells with stem-like properties from the gastric cancer cell lines MKN45 and SGC7901

Traditionally, it was presumed that gastric cancer was derived from tumor cells with stem-like properties. In the present study, stem-like cells from the gastric cancer cell lines MKN45 and SGC7901 were enriched by growing them as spheres in a defined serum-free medium. Following enrichment for stem-like cells, cluster of differentiation (CD)24 and CD44 were applied as candidate stem cell markers to examine the expression profile. It was revealed that the sphere-derived cells contained a higher proportion of cells expressing the stem cell surface markers CD24 and CD44 when compared with the parental cells. It was also identified that the expression of cytokeratin 18 in sphere-derived cells was decreased and the expression of vimentin and aldehyde dehydrogenase 1 (ALDH1) was increased compared with the parental cells. This finding supports the existence of a population of tumor sphere-forming cells with stem cell properties in the MKN45 and SGC7901 cell lines. Furthermore, the stem cell population was enriched in cells expressing CD24, CD44, vimentin and ALDH1 cell surface markers. These results support the existence of gastric cancer stem cells and provide an alternative approach to the diagnosis and treatment of gastric cancer.