title: Berberine inhibits proliferation and down-regulates epidermal growth factor receptor through activation of Cbl in colon tumor cells.
abstract: Berberine, an isoquinoline alkaloid, is an active component of Ranunculaceae and Papaveraceae plant families. Berberine has been found to suppress growth of several tumor cell lines in vitro through the cell-type-dependent mechanism. Expression and activation of epidermal growth factor receptor (EGFR) is increased in colonic precancerous lesions and tumours, thus EGFR is considered a tumour promoter. The aim of this study was to investigate the effects and mechanisms of berberine on regulation of EGFR activity and proliferation in colonic tumor cell lines and in vivo. We reported that berberine significantly inhibited basal level and EGF-stimulated EGFR activation and proliferation in the immorto Min mouse colonic epithelial (IMCE) cells carrying the APC(min) mutation and human colonic carcinoma cell line, HT-29 cells. Berberine acted to inhibit proliferation through inducing G1/S and G2/M cell cycle arrest, which correlated with regulation of the checkpoint protein expression. In this study, we also showed that berberine stimulated ubiquitin ligase Cbl activation and Cbl's interaction with EGFR, and EGFR ubiquitinylation and down-regulation in these two cell lines in the presence or absence of EGF treatment. Knock-down Cbl expression blocked the effects of berberine on down-regulation of EGFR and inhibition of proliferation. Furthermore, berberine suppressed tumor growth in the HT-29 cell xenograft model. Cell proliferation and EGFR expression level was decreased by berberine treatment in this xenograft model and in colon epithelial cells of APC(min/+) mice. Taken together, these data indicate that berberine enhances Cbl activity, resulting in down-regulation of EGFR expression and inhibition of proliferation in colon tumor cells.
authors: Cancer Center, Xiamen University Medical College, Xiamen, People's Republic of China.
authors: Lihong
authors: L
authors: Wang
authors: Hailong
authors: H
authors: Cao
authors: Ning
authors: N
authors: Lu
authors: Liping
authors: L
authors: Liu
authors: Bangmao
authors: B
authors: Wang
authors: Tianhui
authors: T
authors: Hu
authors: Dawn A
authors: DA
authors: Israel
authors: Richard M
authors: RM
authors: Peek
authors: D Brent
authors: DB
authors: Polk
authors: Fang
authors: F
authors: Yan
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001599:Berberine / Q000494:pharmacology*; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000473:pathology*; D015536:Down-Regulation / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D066246:ErbB Receptors / Q000235:genetics*; D019073:HT29 Cells; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D050721:Proto-Oncogene Proteins c-cbl / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D001599:Berberine; D050721:Proto-Oncogene Proteins c-cbl; D066246:ErbB Receptors