Preliminary Isolation And Identity Of Cancer Stem Cells In Four Tumor Cell Lines

Tumor is one of the main causes of death, the current main measures is surgical treatment and anti-proliferation treatments, but these treatments often unpredictably occur of malignant cells'metastasis, which brought in obstacles to cure cancer. Recently it has been found there is a small group of highly tumorigenic ability cells in tumor, these cells may be derived from the transformation of normal stem cells. There is increasing evidence that tumor growth and metastasis require these small number of cell subsets, they have the characteristics of stem cells, known as the "cancer stem cells" (CSCs) or "tumor initiating cells" (TICs). Currently, CSCs isolated only from the telomerase-positive cell lines, but whether telomerase-free cancer cell lines have CSCs has not been reported.In this study, three telomerase-free osteosarcoma cell line U-2OS, Saos-2 and SCID22-3B-1, a lung cancer cell lines XWLC-05 as the research object, using adherent, low adhesive and soft agar culture method to detect the proliferation characteristics in vitro; using methods of side population (SP) and immunoflurescence staining with CD 133 detect CSCs in tumor cell lines. Result shows that we can isolated 0.3% and about 2% CSC-like cells from the SCID22-3B-1 and XWLC-05, and only CSC-like cells of XWLC-05 are highly tumorigenic in nude mice, that is 2000 cells can induce tumor, however unsorted cells of XWLC-05 were at least 1 X 105 cells can cause tumors, and both can be subculture. There are no CD133 expression in U-2OS, Saos-2 and SCID22-3B-1. Monoclonal cell lines, isolated from lung cancer cell line and side population cells, all contain side population cells and have strong tumorigenicity, which mean the phenomenon of differentiation; with the use of low adhesive culture methods, CSCs were not significantly increased. In soft agar test, U-2OS, Saos-2 and SCID22-3B-1 can not form spheres, while XWLC-05 can form spheres, the percentage of form spheres is related to tumorigenity of SP cells.This study shows that there maybe no CSCs exsited in telomerase-free tumor cell lines; Secondly, XWLC-05 has strong tumorigenicity and can be isolated of high tumorigenic CSCs from it.