ABSTRACT
Objective To explore the effect of psoralen on topoisomerase IIα(TopoIIα) expression of breast cancer stem cells.Methods CD44+CD24-/low breast cancer stem cells were sorted from MCF-7/ADR by magnetic-activated cell sorting(MACS).We observed the growth characteristics of these stem cells through optical microscope and detected the growth-inhibitory effects of psoralen on breast cancer stem cells by CCK-8 assay and IC50 of adriamycin and adriamycin combined with psoralen to calculate the reversal index.The mRNA and protein expressions of Topo IIα were detected using RT-PCR and Western blot, respectively.Results Under the optical microscope, breast cancer stem cells presented spheres.IC10 and IC20 of psoralen on breast cancer stem cells were (6.77±0.23)μg/mL and (10.36±0.21)μg/mL.IC50 of adriamycin and adriamycin combined with psoralen on breast cancer stem cells was (90.03±3.56)μg/mL and (21.47±0.82)μg/mL, the reversal index was 4.19.Psoralen significantly raised the expressions of Topo Ⅱα at mRNA and protein levels.Conclusion Psoralen reversed the resistance of adriamycin by increasing the gene and protein expressions of breast cancer stem cells Topo Ⅱα and the drug targets.
ABSTRACT
BACKGROUND:Breast cancer stem cells not only lead to theoccurrence 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.