The anti-ulcer agent, irsogladine, increases insulin secretion by MIN6 cells

18β-Glycyrrhetinic Acid Has Anti-Cancer Effects via Inducing Apoptosis and G2/M Cell Cycle Arrest, and Inhibiting Migration of A549 Lung Cancer Cells

Background

18β-glycyrrhetinic acid (18β-Gly), which is extracted from licorice root, has various pharmacological properties; however, its anti-cancer effects on lung cancer cells have not been fully established.

Purpose

In this study, we investigated the underlying molecular mechanisms of 18β-Gly.

Results

Our results showed that 18β-Gly had significant cytotoxic effects and no apparent side effects. 18β-Gly induced mitochondria-dependent apoptosis of A549 lung cancer cells. In addition, after treatment with 18β-Gly, intracellular reactive oxygen species (ROS) levels were significantly increased, and G2/M cell cycle arrest and inhibition of cell migration were induced via the mitogen-activated protein kinase (MAPK)/signal transducer and activator of transcription 3 (STAT3)/nuclear factor kappa (NF-κB) signaling pathways. After pretreatment with the ROS scavenger N-acetyl-L-cysteine or MAPK inhibitors, the expression levels of phosphorylated p38 (p-p38), phosphorylated c-Jun N-terminal kinase, inhibitor of nuclear factor kappa B, cleaved caspase-3 (cle-cas-3), cleaved poly (ADP ribose) polymerase (cle-PARP), p-p53, p27, p21, and E-cadherin were decreased; and levels of phosphorylated extracellular signal-regulated kinase, p-STAT3, NF-κB, Bcl-2, cyclin B1, cyclase-dependent kinase 1/2 (CDK1/2), N-cadherin, vimentin, and snail homolog 1 (SNAI 1) were increased. In addition, the percentage of cells in the G2/M phase was decreased, and inhibition of migration was reduced.

Conclusion

In summary, 18β-Gly induced apoptosis and G2/M cell cycle arrest and inhibited migration via the ROS/MAPK/STAT3/NF-κB signaling pathways in A549 lung cancer cells. Therefore, 18β-Gly is a novel promising candidate for the treatment of lung cancer.

Volatile anesthetics suppress glucose-stimulated insulin secretion in MIN6 cells by inhibiting glucose-induced activation of hypoxia-inducible factor 1

Proper glycemic control is one of the most important goals in perioperative patient management. Insulin secretion from pancreatic β-cells in response to an increased blood glucose concentration plays the most critical role in glycemic control. Several animal and human studies have indicated that volatile anesthetics impair glucose-stimulated insulin secretion (GSIS). A convincing GSIS model has been established, in which the activity of ATP-dependent potassium channels (K_ATP) under the control of intracellular ATP plays a critical role. We previously reported that pimonidazole adduct formation and stabilization of hypoxia-inducible factor-1α (HIF-1α) were detected in response to glucose stimulation and that MIN6 cells overexpressing HIF-1α were resistant to glucose-induced hypoxia. Genetic ablation of HIF-1α or HIF-1β significantly inhibited GSIS in mice. Moreover, we previously reported that volatile anesthetics suppressed hypoxia-induced HIF activation in vitro and in vivo.To examine the direct effect of volatile anesthetics on GSIS, we used the MIN6 cell line, derived from mouse pancreatic β-cells. We performed a series of experiments to examine the effects of volatile anesthetics (sevoflurane and isoflurane) on GSIS and demonstrated that these compounds inhibited the glucose-induced ATP increase, which is dependent on intracellular hypoxia-induced HIF-1 activity, and suppressed GSIS at a clinically relevant dose in these cells.