CD133(+) single cell-derived progenies of colorectal cancer cell line SW480 with different invasive and metastatic potential.

Single cell progenies (SCPs) inherit biological properties from their isogenetic mother cells. If a single cancer cell can give rise to progenies, which can be passaged sustainably in vitro and produce tumor in xenotransplantation, the cell should be cancer initiating cell. CD133 (Prominin-1, Prom1) is the marker of human colorectal cancer (CRC) stem cells and probably a marker of metastatic cancer stem cells (CSCs). Thirty-three SCPs of CRC cell line SW480 were isolated by limited dilution methods, thirty of which are CD133 positive and three negative. All of the CD133(+) SCPs are tumorigenic, and the subcutaneous tumors expanded rapidly, while only 1 of 3 CD133(-) SCPs developed a minimal tumor in nude mice. Orthotopic transplantation experiments showed that CD133(+) SCPs possessed heterogeneity in intestinal wall invasion, lymph node and liver metastases. CD133(+) SCPs varied in cell growth, invasive ability, epithelial-mesenchymal-transition and expression of CSCs markers (CD133, CD44, and CXCR4) associated with metastatic potential. CD133(-) SCPs did not produce secondary transplanted tumor, intestinal invasion and metastasis. The results indicated CD133(+) subpopulation of SW480 SCPs bear heterogeneous invasive and metastatic ability, and CRC-CSCs might be a heterogeous subpopulation.