ABSTRACT
@# Objective: To explore the resistance of CD133+ cells in HepG2 cell line to doxorubicin (DOX) and its mechanism. Methods: CD133+ cells were sorted by magnetic beads and CD133+ positive rate was detected by flow cytometry. MTT assay was used to detect the resistance to DOX-induced apoptosis of CD133+ cells. The expression of BCRP transporter mRNA was detected by RT-PCR. The expression of apoptosis-related proteins was detected by Western blotting. Immunofluorescence assay was used to detect the activation and transportation of P65 after DOX treatment. Results: Magnetic beads sorting could efficiently sort the CD133+ cells from HepG2 cells. MTT proliferation assay showed that CD133+ cells had stronger resistance to DOX than CD133- cells (P<0.05). Immunofluorescence showed that the activation rate and content of P65 in CD133+ cells were significantly higher than those in CD133- cells and HepG2 cells (P<0.05). The results of RT-PCR showed that the mRNA content of BCRP in CD133+ cells was significantly increased compared with CD133- cells and HepG2 cells (all P<0.05). Compared with HepG2 and CD133- groups, the expression of Bax and p53 in CD133+ cells was significantly decreased (P<0.05), while the expression of Bcl-2 and Survivin protein in CD133+ cells was significantly increased (P<0.05 or P<0.01). Conclusion: The molecular mechanism of high DOX-resistance of the CD133+ cell subsets in HepG2 cells is the high expression of the survival-related proteins NF-κB, Bcl-2, Survivin and the drug-resistance transporter BCRP, and low expression of apoptosis-promoting proteins p53 and Bax.