Fluorouracil selectively enriches stem-like cells in the lung adenocarcinoma cell line SPC.

Most adult stem cells are in the G0 or quiescent phase of the cell cycle and account for only a small percentage of the cells in the tissue. Thus, isolation of stem cells from tissues for further study represents a major challenge. This study sought to enrich cancer stem cells and explore cancer stem-like cell clones using 5-fluorouracil (5-FU) in the lung adenocarcinoma cell line, SPC. Proliferation inhibition was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, according to which half maximal inhibitory concentration values were calculated. Expression levels of stem cell markers after treatment with 5-FU were examined using immunofluorescence and Western blotting. Additionally, side population (SP) cells were sorted using FACS. Properties of SP cells were evaluated by using Transwell, colony-forming assays, and tumor formation experiments. 5-FU greatly inhibits proliferation, especially of cells in S phase. SP cells possess greater invasive potential, higher clone-forming potential, and greater tumor-forming ability than non-SP cells. Treatment with 5-FU enriches the SP cells with stem cell properties in human lung adenocarcinoma cell lines.