Octreotide Alleviates Autophagy by Up-Regulation of MicroRNA-101 in Intestinal Epithelial Cell Line Caco-2

摘要

Background Intestinal mucositis is a common side-effect after anti-cancer therapy, which may greatly restrict the therapeutic effects. We aimed to explore the functional role of octreotide (OCT) in lipopolysaccharide (LPS)-induced autophagy of human intestinal epithelial cells as well as the underlying mechanisms. Methods Cell viability and expression of proteins related to autophagy, AMPK and the mTOR pathway in LPS-treated Caco-2 cells were determined by CCK-8 assay and Western blot analysis, respectively. Effects of OCT on LPS-induced alterations as well as miR-101 expression were measured. Then, miR-101 was aberrantly expressed, and whether OCT alleviated LPS-induced autophagy through miR-101 was tested. Next, whether TGF-β-activated kinase 1 (TAK1) was involved in the regulation of miR-101 in LPS-induced autophagy was studied. Effects of OCT on monolayer permeability and tight junction level were analyzed via measuring transepithelial electrical resistance (TEER) and expression of tight junction proteins. Results LPS reduced cell viability and increased autophagy through activating AMPK and inhibiting the mTOR pathway in Caco-2 cells. OCT alleviated LPS-induced alterations and repressed degradation of autophagosome. Then, we found that OCT affected autophagy through up-regulating miR-101 in LPS-treated cells. Moreover, miR-101-induced inactivation of AMPK and activation of the mTOR pathway in LPS-treated cells were reversed by inhibition of TAK1 phosphorylation. Finally, we found miR-101 was up-regulated in differentiated cells, and OCT protected the monolayer permeability and tight junction level. Conclusion OCT repressed autophagy through miR-101-mediated inactivation of TAK1, along with inactivation of AMPK and activation of the mTOR pathway in LPS-treated Caco-2 cells.