Berberine inhibits epithelial-mesenchymal transition and promotes apoptosis of tumour-associated fibroblast-induced colonic epithelial cells through regulation of TGF-β signalling
Tumor-associated fibroblasts (TAFs) play a crucial role in modulating the differentiation of neighboring stromal cells. Berberine (BBR), a bioactive compound derived from traditional Chinese herbs, has demonstrated potent anticancer properties. However, its impact on the differentiation of normal colonic epithelial cells induced by TAFs remains unclear. In this study, we utilized the TAF-like myofibroblast cell line CCD-18Co to explore this effect. Conditioned medium (CM) derived from CCD-18Co cells, as well as co-culture with these cells, induced epithelial-mesenchymal transition (EMT) in colonic epithelial HCoEpiC cells, characterized by reduced E-cadherin expression and increased levels of vimentin and α-SMA. Moreover, CCD-18Co cells promoted the expression of EMT-related transcription factors ZEB1 and Snail, as well as enhanced cell motility.
We tested the effects of LY364947, a selective inhibitor of TGF-β receptor type I (TβRI) kinase, and BBR. Our findings revealed that both LY364947 and BBR effectively inhibited these EMT-associated changes. BBR, in particular, downregulated ZEB1 and Snail expression in a dose-dependent manner. Additionally, BBR reduced the levels of TβRI, TβRII, Smad2/p-Smad2, and Smad3/p-Smad3, indicating its influence on the TGF-β signaling pathway. Furthermore, BBR induced apoptosis in EMT-like HCoEpiC cells in a concentration-dependent manner, with an upregulation of Bax and a downregulation of Bcl-2. Notably, the p38 MAPK inhibitor VX-702 significantly attenuated apoptosis, suggesting a critical role for p38 MAPK in this process. BBR also enhanced the expression and phosphorylation of p38 MAPK.
In summary, our results demonstrate that berberine inhibits EMT and promotes apoptosis in TAF-induced colonic epithelial cells, likely through both Smad-dependent and Smad-independent TGF-β signaling pathways.