[摘要] 目的: 探讨HepG2 中CD133+细胞对多柔比星（doxorubicin，DOX）的抗性及其作用机制。方法: 通过磁珠分选实验对HepG2 细胞中CD133+细胞进行分选，流式细胞术检测CD133+细胞阳性率，MTT法检测CD133+细胞对DOX诱导凋亡的抗性，免疫荧光实验检测DOX处理各组细胞后P65 激活转运情况，qRT-PCR检测各组细胞乳腺癌耐药蛋白（breast cancer resistance protein,BCRP) mRNA表达水平；Western blotting 检测CD133+细胞凋亡相关蛋白的表达。结果: 磁珠分选可以高效地富集HepG2 细胞中CD133+细胞。与CD133-细胞相比，CD133+细胞对DOX具有更强的抗性（P<0.05）；与CD133-细胞、HepG2 细胞相比，CD133+细胞中P65 激活速度与表达水平明显提高（均P<0.05）；CD133+细胞中BCRP mRNA表达水平明显高于CD133-细胞和HepG2 细胞（均P<0.05）；与HepG2、CD133-组相比，CD133+细胞组Bax 和p53 蛋白表达水平显著减少、Bcl-2 和Survivin 蛋白表达量显著增加（P<0.05 或P<0.01）。结论: HepG2 细胞中CD133+细胞亚群对DOX 高耐药性的分子机制在于高表达存活相关蛋白NF-κB、Bcl-2、Survivin以及耐药性转运蛋白BCRP，而低表达促凋亡相关蛋白p53、Bax。

[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.