中文摘要：

背景：乳腺癌干细胞不仅导致乳腺癌的发生,还可能导致乳腺癌的转移及复发。干细胞与细胞耐药性的关系也受到人们越来越多的重视,把治疗的重点放到对干细胞的治疗上,可能会起到意想不到的结果。目的：探索补骨脂素对人乳腺癌MCF-7/ADR细胞中谷胱甘肽-S-转移酶π的逆转作用及机制。方法：（1）无血清培养基悬浮培养富集乳腺癌MCF-7/ADR干细胞群;（2）以RT-PCR和Western Blot检测0,4,8,12,16 mg/L补骨脂素对MCF-7/ADR干细胞中谷胱甘肽-S-转移酶π基因及蛋白表达水平的影响;（3）Western Blot技术检测0,8 mg/L补骨脂素处理前后核内核因子κB的活化状态;（4）RT-PCR技术检测18μmol/L SN50及8 mg/L补骨脂素对谷胱甘肽-S-转移酶π的表达水平;（5）CCK-8实验检测阿霉素对细胞增殖的影响。结果与结论：补骨脂素能显著降低MCF-7/ADR细胞中谷胱甘肽-S-转移酶π基因及蛋白表达水平,且补骨脂素能明显抑制核因子κB的活化。提示补骨脂素通过减少谷胱甘肽-S-转移酶π表达水平进而逆转人乳腺癌MCF-7/ADR干细胞多药耐药,其机制可能是通过抑制核因子κB信号通路来实现。

英文摘要：

BACKGROUND：Breast cancer stem cells not only lead to the occurrence of breast cancer, but also may cause breast cancer metastasis and recurrence. The relationship between stem cells and cell resistance is also gaining increasing attentions, and the focus on the stem cell treatment may result in unexpected results.OBJECTIVE：To explore the reversal effect of psoralen on glutathione-S-transferase π （GST-π） in human breast cancer MCF-7/ADR cells and its mechanism.METHODS：MCF-7/ADR cells were cultured and enriched in serum-free medium to obtain breast cancer stem cells.RT-PCR and western blot were used to detect the expression of GST-π at the levels of gene and protein in the MCF-7/ADR cells after treatment with 0, 4, 8, 12, 16 mg/L psoralen. To observe the activation of nuclear factor-κB,western blot was used. The expression of GST-π was detected by RT-PCR in 18 μmol/L SN50 group and 8 mg/L psoralen group. Cell counting kit-8 assay was used to detect the effect of doxorubicin on cell proliferation.RESULTS AND CONCLUSION：Compared with the control group, psoralen reduced the expression of GST-π at the mRNA and protein levels, and significantly inhibited the activation of nuclear factor-κB. It was suggested that psoralen could reverse the multidrug resistance of human breast cancer MCF-7/ADR stem cells by decreasing the expression level of GST-π. The mechanism may be achieved by inhibiting the nuclear factor-κB signal pathway.