The Correlation Between Colon Cancer Stem Cells-Enriched Spheroid Cells And Epithelial-mesenchymal Transition

Objectives: To investigate whether spheroid cells formed from colon cancer cell linescan enrich cancer stem cells or not, and whether they went throughEpithelial-mesenchemal Transition or not.Methods: Colon cancer cell line HT29and HCT116were cultured in serum freemedium to form spheroid cells. Then check the expression of stem cell markers onspheroid cells. The migration and invasive experiment were carried out usingTranswell technique. Soft agar assay was used to measure both adhered and spheroidcells’ ability of forming cell clones. RT-PCR and Western blot were used to measurethe expression of E-cadherin, ZO-1, snail and vimentin in these cells.Results: Both HT29and HCT116cells can form spheroid cells, and expression ofstem cell markers on spheroid cells was increased. In Transwell and soft agar assay,the migrate, invasive and clone forming capability of spheroid cells is significantlyhigher than the adherent cells (P0.05). The epithelial gene ZO-1is significantlylower in spheroid cells than in adherent cells, and the mesenchymal gene vimentinand fibronectin are significantly higher in spheroid cells than in adherent cells (P0.05).Conclusion: Colon cancer cell line HT29and HCT116can form spheroid cells inserum free medium. These spheroid cells express stem cell markers, suggesting theyhave high percentage of cancer stem cells. The higher migrate, invasive and clone forming ability of spheroid cells indicates that cancer stem cells can enhance tumors’malignant behaviors. Decreased epithelial traits and increased mesenchymal traits inspheroid cells on both gene and protein level suggest that epithelial-mesenchymaltransition plays crucial role in the formation of cancer stem cells.