Expression of stem cell markers in side population cells sorted from SMMC-7721 cell line

Objective To study the expression of stem cell markers in side population cells sorted from SMMC-7721 cell line. Methods Fluorescence-activated cell sorting （FACS） was used to sort side population （SP） cells and non-SP （NSP） cells from SMMC-7721 cell line. Real-time polymerase chain reaction （PCR） and flow cytometry （FCM） were used to evaluate the expression of several stem cell markers such as ABCC2, CD133, Oct4, Sox2 and NANOG in SP cells and NSP cells. Results FACS analysis indicated that （9. 2 ±0. 2） % of the SMMC-7721 cells were SP cells. Real-time PCR analysis suggested that ABCC2, CD133, Oct4, Sox2 and NANOG were expressed in the SP cells at higher levels than the NSP cells by about 7. 132, 4. 985, 8. 642, 5. 095 and 5. 164 folds, respectively （P 〈 0. 01 ）. FCM analysis revealed that the expression of ABCC2, CD133, Oct4, Sox2 and NANOG proteins in SP cells was （92. 65±3.92）%, （12.75 ±1.62）%, （17.35 ±2.31）%, （9.57 ±1.71）% and （28.39 ±5.28）% respectively, while in NSP cells that was （0.26±0.06）%, （2.51±0. 17）%, （1.74±0.38）%, （1.52 ±0.41）% and （3.37 ± 1.02） % respectively （P 〈 0. 01 ）. Conclusion The SP cells sorted from SMMC-7721 cell line may enrich tumor stem cells. Purified liver cancer stem ceils may be obtained by screening SP cells using a variety of stem cell markers. Key words: Carcinoma, hepatocellular;  Side population cell;  Tumor stem cell