MiR-542-5p Inhibits Hyperglycemia and Hyperlipoidemia by Targeting FOXO1 in the Liver.

PURPOSE: This research was designed to investigate how miR-542-5p regulates the progression of hyperglycemia and hyperlipoidemia. MATERIALS AND METHODS: An in vivo model with diabetic db/db mice and an in vitro model with forskolin/dexamethasone (FSK/DEX)-induced primary hepatocytes and HepG2 cells were employed in the study. Bioinformatics analysis was conducted to identify the expression of candidate miRNAs in the liver tissues of diabetic and control mice. H&E staining revealed liver morphology in diabetic and control mice. Pyruvate tolerance tests, insulin tolerance tests, and intraperitoneal glucose tolerance test were utilized to assess insulin resistance. ELISA was conducted to evaluate blood glucose and insulin levels. Red oil O staining showed lipid deposition in liver tissues. Luciferase reporter assay was used to depict binding between miR-542-5p and forkhead box O1 (FOXO1). RESULTS: MiR-542-5p expression was under-expressed in the livers of db/db mice. Further in vitro experiments revealed that FSK/DEX, which mimics the effects of glucagon and glucocorticoids, induced cellular glucose production in HepG2 cells and in primary hepatocytes cells. Notably, these changes were reversed by miR-542-5p. We found that transcription factor FOXO1 is a target of miR-542-5p. Further in vivo study indicated that miR-542-5p overexpression decreases FOXO1 expression, thereby reversing increases in blood glucose, blood lipids, and glucose-related enzymes in diabetic db/db mice. In contrast, anti-miR-542-5p exerted an adverse influence on blood glucose and blood lipid metabolism, and its stimulatory effects were significantly inhibited by sh-FOXO1 in normal control mice. CONCLUSION: Collectively, our results indicated that miR-542-5p inhibits hyperglycemia and hyperlipoidemia by targeting FOXO1.

Oridonin enhances the anti-tumor activity of gemcitabine towards pancreatic cancer by stimulating Bax- and Smac-dependent apoptosis.

BACKGROUND: Oridonin has been shown to exhibit potent anti-tumor activity, but the exact mechanisms underlying this activity remains unclear. Here, we investigated whether oridonin could synergistically enhance the activity of gemcitabine against BxPC-3 pancreatic cancer cells. METHODS: CCK-8 assays were conducted to determine cell viability. The cellular morphology was observed under light microscope and compared with normal cell. Apoptotic cells were quantified by flow cytometry. RT-PCR, Western blot analysis and immunohistochemical methods were employed to analyze related-gene and protein expression. A xenograft tumor model was conducted whereby BxPC-3 cells were introduced into nude mice to detect anti-tumor effects in vivo. RESULTS: In vitro, oridonin inhibited the proliferation of BxPC-3 and Panc-1 cells cells in a concentration and time dependent manner. In addition, oridonin dose-dependently induced Panc-1 cellular morphology changes. Besides, In BxPC-3 cells oridonin potentiated gemcitabine-induced apoptosis. oridonin induced Bax translocation from cytosolic to mitochondrial compartments. This was accompanied by the release of the apoptogenic protein Smac and inhibition of its downstream target XIAP. These effects were further enhanced by combined treatment with oridonin and gemcitabine. In vivo, both oridonin alone and in combination with gemcitabine significantly suppressed tumor growth in a Bax- and Smac-dependent manner. CONCLUSIONS: Oridonin can potentiate the effects of gemcitabine through Bax- and Smac-dependent mitochondrial signaling pathways in BxPC-3 pancreatic cancer cells. Therefore, oridonin has the potential to be used clinically in the treatment of pancreatic cancer.