Abstract
Background: Tanshinone IIA (Tan IIA) is a major active ingredient extracted from Salvia miltiorrhiza, which has been proved to inhibit metastasis of various cancers including colorectal cancer (CRC). However, the detailed mechanisms of Tan IIA against CRC metastasis are not well explored. Epithelial-to-mesenchymal transition (EMT) exerts an important regulatory role in CRC metastasis, and our previous mechanism studies demonstrated that β-arrestin1 could regulate CRC EMT partly through β-catenin signaling pathway. Therefore, in this work we investigated whether Tan IIA could regulate CRC EMT through β-arrestin1-mediated β-catenin signaling pathway in vivo and in vitro.Methods: The nude mice tail vein metastasis model was established to observe the effect of Tan IIA on CRC lung metastasis in vivo. The lung metastasis was evaluated by living animal imaging and hemaoxylin-eosin staining. The migratory ability of CRC cells in vitro were measured by transwell and wound healing assays. The protein expression and cellular localization of β-arrestin1 and β-catenin were characterized by immunofluorescence staining and western blot. The β-catenin signaling pathway related proteins and EMT associated proteins in CRC cells were detected by western blot and immunohistochemistry. Results: Our results showed that Tan IIA inhibited the lung metastases of CRC cells in vivo and extended the survival time of nude mice. In vitro, Tan IIA increased the expression of E-cadherin, decreased the secretion of Snail, N-cadherin and Vimentin, thus suppressed EMT and the migratory ability of CRC cells. Further study found the mechanism involving in Tan IIA regulating EMT and metastasis, referring to the suppression of β-arrestin1 expression, reduction of β-catenin nuclear localization, thereby the decreased activity of β-catenin signaling. Conclusion: Our data revealed a new mechanism of Tan IIA on the suppression of EMT and metastasis in CRC via β-arrestin1-mediated β-catenin signaling pathway, and provided support for Tan IIA as anti-metastatic agents in CRC.
Akt2 Mediates TGF-�1-Induced Epithelial to Mesenchymal Transition by Deactivating GSK3�/Snail Signaling Pathway in Renal Tubular Epithelial Cells