Aim of the study
To investigate the activity and mechanism of total flavonoids of litchi seed (TFLS) against BCSCs in vitro and in vivo. Materials and
Conclusions
TFLS could suppress the growth of breast cancer and eliminate breast cancer stem cells by inhibiting the Notch3 signaling pathway.
Methods
Two orthotopic xenograft mouse models were established using HCC1806 cells pretreated or untreated with TFLS to determine whether TFLS could target BCSCs in vivo. Mammosphere formation and flow cytometry assays were employed to evaluate the effect of TFLS on BCSCs in vitro. The underlying mechanism was investigated using RT-qPCR, Western blot, immunohistochemistry and immunofluorescence experiments.
Results
TFLS could significantly inhibit the viability of HCC1806, MCF-7 and HCC1937 cells in vitro and suppress the growth of HCC1806 cells in vivo. TFLS attenuated stem cell-like properties of breast cancer through reducing the percentage of CD44+CD24-/low cells, inhibiting the mammospheres formation and down-regulating the mRNA and protein levels of cancer stem cells related markers (Oct4, Nanog, Sox2) in MCF-7 and HCC1806 cells. Meanwhile, TFLS suppressed the tumor-initiating ability of BCSCs via reducing the percentage of CD44+CD24-/low cells in tumor and lowering tumor incidence rate in orthotopic xenograft mice. In addition, TFLS treatments restricted the expression and nuclear translocation of Notch3, subsequently down-regulated Hes1 and Runx2 expressions. Conclusions: TFLS could suppress the growth of breast cancer and eliminate breast cancer stem cells by inhibiting the Notch3 signaling pathway.