Berberine Promotes Mouse Breast Cancer Metastasis to Lung via Inducing Epithelial–mesenchymal Transition

Objective To study the effect and mechanism of berberine (BBR) on the lung metastasis of mouse breast cancer via epithelial-mesenchymal transition (EMT).

Methods CCK-8 and Transwell migration assays were utilized to investigate the proliferation and migration properties of breast cancer 4T1 cells after BBR treatment.Mouse 4T1-Luc cells were injected into mice under the fourth mammary fat pad, and the mice were then randomly divided into the control and BBR groups.The mice in the BBR group received daily intraperitoneal injections of BBR working solution and those in the control group were continuously intraperitoneally injected with the same volume of the solvent used to dissolve BBR powder.Tumor metastasis in the lungs of living mice was detected by using an in vivo imaging system.After 42 days of administration, lung metastasis was measured via microscopy and HE staining.Western blot analysis was used to examine the effects of BBR on the expression of EMT-related proteins (Vimentin and Snail) as well as the activation of the Akt and ERK signaling pathways.

Results BBR significantly promoted 4T1 cell migration (P < 0.05).In vivo experiments showed that the number of lung metastases in the BBR group had significantly increased compared with that in control group (P < 0.05) as observed under microcopy and histological staining.Compared with the control group, BBR upregulated the expression levels of Vimentin and Snail as well as the phosphorylated levels of p-Akt and p-ERK (P < 0.05).

Conclusion BBR may promote EMT and lung metastasis of breast cancer 4T1 cells by activating the expression of proteins in the p-Akt and p-ERK pathways.