This study aimed to explore cell surface biomarkers related to cancer stem cells (CSCs) and their role in the tumorigenesis of colon cancer. Various colon cancer cell lines were screened for CD133 and CD44 expression. CD44(high)/CD133(high) and CD44(low)/CD133(low) cells were separately isolated by Fluorescence-Activated Cell Sorting (FACS). The cell proliferation, colony formation, cell cycle characteristics, and tumorigenic properties in CD44(high)/CD133(high) and CD44(low)/CD133(low) cells were investigated through in vitro experiments and in vivo tumor xenograft models. The expression profiles of stem cell-related genes were examined by RT-PCR. With HCT-116 cells, flow cytometry analysis revealed that CD44(high)/CD133(high) cells had higher proliferation potency than CD44(low)/CD133(low) cells. Compared to CD44(low)/CD133(low) cells, CD44(high)/CD133(high) cells had more stem cell-related genes, and displayed increased tumorigenic ability. In summary, CD44(high)/CD133(high) cells isolated from HCT-116 cells harbor CSC properties that may be related to the tumor growth of colon cancer. These results suggest that CD44 and CD133 could be strong markers of colorectal cancer stem cells.
Keywords: CD133; CD44; biomarkers; cancer stem cells (CSCs); colorectal cancer.