Berberine inhibits colorectal liver metastasis via modulation of TGF-[beta] in a cecum transplant mouse model

Background Hepatic metastasis is the primary cause of colorectal cancer (CRC)-induced death. Our previous results showed the anti-metastatic effects of Coptidis rhizoma using in vitro model. Aim The present study aimed to investigate whether berberine, the main active compound of C. rhizoma, inhibits colon-liver metastasis in an animal model, and to elucidate the underlying mechanisms. Methods Murine colon carcinoma (CT26) tumor tissue was implanted into the cecum of balb/c mice with/without oral administration of berberine (100 mg/kg) for 21 days, after which liver metastasis was evaluated. In addition, the pharmacological actions of berberine were explored using 5-fluorouracil-resistant human colon cancer cells (HCT116/R). Result The administration of berberine significantly decreased the number of tumor nodules in the liver, while significant activation of E-cadherin (an epithelial marker), and suppression of vimentin, Snail and TGF-[beta] (mesenchymal markers) were observed in primary colon tumor tissues. Berberine treatment also notably lowered the levels of inflammatory cytokines (TGF-[beta], TNF- [alpha], IL-6 and IL-1[beta]) in the blood. In HCT116/R cells, berberine significantly inhibited migration and invasion and modulated the expression of TGF-[beta] and representative molecules related to its pathway. The results obtained with a TGF-[beta] inhibitor (SB431542) and a TGF-[beta] siRNA, strongly suggest that the mechanism of action of berberine is linked to TGF-[beta] signaling. Conclusion In conclusion, berberine evidently possess an anti-colon-liver metastatic effect, and its underlying mechanisms involve the inhibition of epithelial-mesenchymal transition (EMT) through the TGF-[beta] signaling pathway. Thus, we cautiously propose the pharmacological potential of berberine in drug research studies targeting hepatic metastasis from CRC. Keywords: Colorectal cancer, Metastasis, 5-Fluorouracil, EMT, Berberine, TGF-[beta], Drug resistance