OBJECTIVETo investigate the effect of 5-FU (5-fluorouracil) on enriching cancer stem cells of HCC cell line BEL-7402 and the biological characteristics of enriched cells.

METHODSThe enriching concentration of 5-FU was determined by CCK-8 (cell counting kit-8). Flow Cytometry was used to determine the changes in cell cycle and positive expression ratio of surface marker CD56, CD54, EpCAM and CD133. The self-renewal and differentiation of positive cells were tested by colony formation assay, and were compared with the control group.

RESULTSEnriching concentration of 5-FU was determined as 10 μg/ml with 48 h incubation. After enrichment, G0/G1 phase cells increased from 57.50 %+/-0.98% to 68.70%+/-3.41% (P<0.05). Whereas S phase cells decreased from 40.26%+/-4.12% to 31.80%+/-4.15% (P<0.01); G2/M phase cells disappeared in experimental group, and was 5.80%+/-1.87% in control group (P<0.01). The proportion of the cell cycle changed with significant statistical differences. Meanwhile, positive rate of cell surface makers CD56, CD54, EpCAM and CD133 increased from 0.57%+/-0.12%, 8.10%+/-6.79%, 0.3%+/-0.01% and 3.20%+/-0.99% to 4.13%+/-0.06%, 50.08%+/-1.69%, 0.55%+/-0.07% and 10.51%+/-1.13%, respectively. The difference was significant (P<0.05). The colony forming ratio of CD56, CD54, EpCAM and CD133 negative cells and positive cells were 2.11%+/-0.21%, 3.32%+/-0.31%; 0.86%+/-0.101%, 2.40%+/-0.52 %; 7.19%+/-0.56%, 7.73%+/-0.71%; 2.70%+/-0.26%, 5.75%+/-0.81%, respectively, and significant differences were found between (P<0.05).

CONCLUSION5-fluorouracil enriched the cancer stem cell population in HCC cell line BEL-7402. CD56 and CD54 can be used as important surface markers in research of liver cancer stem cells.