Identification and characterization of SP cells in human lung adenocarcinoma SPC-A1 cells
e22230 Background: There has been an increasing interest in recent years in the role stem cells play in health and disease. With an extensive understanding of their biology, a major role for stem cells in the malignant process has been proposed and the existence of cancer stem cells(CSCs) has been confirmed in hematopoietic malignancies, brain cancer, and solid organ malignancies including breast, prostate, colon, and pancreatic cancer. Lung cancer is the leading cause of cancer mortality in most large cities of China. It is possible that lung cancer contains cancer stem cells responsible for its malignancy. The aim of this study is to identify, characterize and enrich the CSC population that drives and maintains lung adenocarcinoma growth and metastasis. Methods: Side population (SP) cell analysis and sorting were applied to established human lung adenocarcinoma cell line and an attempt to further enrich them by preliminary serum-free culture before fluorescence activated cell sorting(FACS) was done. Stem cell properties of SP cells were evaluated by their proliferative index, colony-forming efficiency, tumorigenic potential, bi-differentiation capacity and the expression of common stem cell surface markers. Results: Lung cancer cells could grow in a serum-free Medium (SFM) as non-adherent spheres similar to neurospheres or mammospheres. The proportion of SP cells in cell spheres was significantly higher than that in cells grown as monolayers. SP cells had a greater proliferative index, a higher colony-forming efficiency and a greater ability to form tumor in vivo. SP cells were both CCA positive and SP-C positive while non-SP cells were only SP-C positive. Flow cytometric analysis of cell phenotyping showed that SP cells expressed CD133 and CD44, the common cell surface markers of cancer stem cells, while non-SP cells only expressed CD44. Conclusions: SP cells existed in human lung adenocarcinoma cell lines and they could be further enriched by preliminary serum-free culture before FACS sorting. SP cells possessed the properties of cancer stem cells. No significant financial relationships to disclose.