Sinomenine hydrochloride suppresses the stemness of breast cancer stem cells by inhibiting Wnt signaling pathway through down-regulation of WNT10B.

Sinomenine hydrochloride (SH) has anti-breast cancer effect, but whether it can act on breast cancer stem cells (BCSCs) is unclear. Here, we explored the effect of SH on BCSCs and its mechanism. We observed that SH decreased the ratio of CD44+/CD24- BCSCs and the expression of BCSCs-related genes in MCF-7 and MDA-MB-231 cells. SH significantly inhibited the stemness of CD44+/CD24- BCSCs, including the capacity of self-renewal, oncosphere formation, migration and invasion, and the expression of stemness-related genes. Furthermore, SH obviously inhibited the expression of Wnt signaling pathway genes in CD44+/CD24- BCSCs, especially the expression of WNT10B and its downstream target genes. While WNT10B was overexpressed, the inhibitory effect of SH on the stemness of BCSCs was blocked, indicating that SH inhibited the stemness of BCSCs by down-regulating WNT10B. When WNT10B was knocked down, the stemness of BCSCs was significantly inhibited, indicating that WNT10B was involved in the stemness maintenance of BCSCs. SH also significantly inhibited the growth of MDA-MB-231 BCSCs xenografts, decreased the expression of BCSCs related genes and suppressed Wnt signaling pathway in vivo. In conclusion, SH negatively regulates the stemness of CD44+/CD24- BCSCs by inhibiting Wnt signaling pathway through down-regulation of WNT10B expression.