To investigate the antitumor and chemoresistance-lowering effects of pectolinarigenin on
breast cancer cells.
Pectolinarigenin was purified by a combination of silica gel and Sephadex LH-20 column
chromatography from ethanol extracts of the aerial parts of C. japonicum
DC. Breast cancer selfrenewal
properties were tested by colony formation and tumor sphere formation assays. Thereafter,
real-time polymerase chain reaction (PCR) was used to detect breast cancer stem cell markers.
Furthermore, the effect of pectolinarigenin on breast cancer cell was evaluated by chemoresistance
using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Finally, tumor
formation in nude mice was used to test the effect of pectolinarigenin on tumorigenicity of breast cancer
cells in vivo.
The results showed that pectolinarigenin, extracted from Cirsium japonicum
Fisch. ex DC.,
inhibited tumor cell self-renewal in MCF-7 breast cancer cells. Pectolinarigenin (25 μM) caused
significant inhibition of colony formation (61.23 %, p < 0.001) and tumor sphere formation (59.49 %, p <
0.01) in MCF-7. The inhibitory effects were associated with changes in breast cancer stem cell markers.
Treatment of breast cancer cells with pectolinarigenin reduced the chemoresistance of the cells to
doxorubicin. At the same time, mRNA expression of chemoresistance genes (ATP binding cassette
subfamily G member 2, ABCG2 and ATP binding cassette subfamily B member 1, MDR1) was
repressed by pectolinarigenin. The inhibition efficiency of MDR1 and ABCG2 by 10 μM pectolinarigenin
treatment was about 59.29 (p < 0.01) and 46.48 % (p < 0.01), respectively. Furthermore,
pectolinarigenin reduced tumor mass in nude mice xenograft model.
Pectolinarigenin inhibits breast cancer stem cell-like properties and lowers the
chemoresistance of the cancer cells to chemotherapy. The results provide an insight into the
mechanism of the anti-breast tumor effects and an experimental basis for the use of pectolinarigenin to
enhance treatment of patients with breast cancer.