Characterization of CD44-positive Cancer Stem-like Cells in COLO 201 Cells

Background/Aim: Cancer stem cells (CSCs) are considered to be one of the causes of tumor recurrence after chemotherapy. The purpose of our study was to isolate CSCs from human colorectal cancer cell (CRC) lines. Materials and Methods: Nine CRC lines were screened based on the expression level of potential CSC markers to identify putative CSCs. Tumor formation capacity in immunodeficient mice was compared with that of their counterparts. Stemness, differentiation potency and sensitivity to 5-fluorouracil (5-FU), in vitro, were also assessed. Microarray analysis was used to characterize the features of the putative CSCs. Results: COLO 201 cells were separated into two populations based on CD44 expression. CD44 positive (CD44⁺) cells showed significantly higher tumor formation capacity than CD44⁻ cells in immunodeficient mice. CD44⁺ cells also possessed stemness properties and lower sensitivity to 5-FU in vitro. Moreover, cancer stemness and chemoresistance-related genes were highly up-regulated in CD44⁺ cells. Conclusion: CD44⁺ COLO 201 cells possessed the features of CSCs; therefore, the present CSC model could serve as a valuable tool to accelerate CSC research.