Screening and identification of oval cells-like stem cells of Thy-1-labeled positive hepatoma carcinoma cells:Are they tumor stem cells? / 中国组织工程研究

ABSTRACT

BACKGROUND:There may be tumor stem cells during metastasis and recurrence of liver cancer.The number of tumor stem cells is very few,so it is difficult to be identified.Thy-1 is a surface marking protein of oval cells.Specific marker can indirectly confirm the existence of tumor stem cells in the tumor,which is a focus in recent studies.OBJECTIVE:To study whether Thy-1 positive marked oval cells was expressed in hepatoma carcinoma cells,and investigate its screening and identification.METHODS:Flow cytometry was used to identify that Thy-1 positive expression in hepatoma carcinoma cells HepG2 and BEL-7402 and normal hepatocytes QSG-7701.Immunomagnetic bead sorting was utilized to select hepatoma carcinoma cells with Thy-1.Immunofluorescence was used to identify selected efficiency.Naked mouse inoculated with hepatoma carcinoma cells in the skin test was assigned to three groups.In the Thy-1~+ cells group,naked mice were inoculated with Thy-1~+ cells (5×10~5/mouse)underneath the skin of the back.In the HepG2 cell positive control group,naked mice were inoculated with HepG2 cells(0.5×10~7/mouse)underneath the skin of the back.In the Thy-1' cells negative control group,naked mice were inoculated with Thy-1~- cells(0.5×10~7/mouse)underneath the skin of the back.Tumorigenicity in each group was observed one month later.RESULTS AND CONCLUSION:Thy-1 expression in hepatoma carcinoma cells HepG2 and BEL7402 was significantly greater compared with normal hepatocytes QSG7701(P＜ 0.05).Positive rate of immunofluorescence staining was 85% in the Thy-1~+ cell group,1% in the HepG2 cell positive control group,0% in the Thy-1~- cell negative control group.There were nubble of five mice in HepG2 cell positive control and Thy-1~+ groups,and the volume was large.However,there was one nubble in Thy-1~- group,and the volume was significantly small(F=144.568,P＜ 0.05).Results indicated that hepatoma carcinoma cells contained Thy-1 labeled positive oval cells-like stem cells,which may be tumor stem cells in hepatoma carcinoma cells.