licochalcone-a and Stomach-Neoplasms

Licochalcone A (LicA) is a chalcone extracted from liquorice which has been used as a traditional Chinese medicine for many generations. Increased glucose consumption and glycolytic activity are important hallmarks of cancer cells, and hexokinase 2 (HK2) upregulation is a major contributor to the elevation of glycolysis. Recently, the antitumor activities of LicA have been reported in various cancers; however, its effect on tumor glycolysis in gastric cancer and the underlying mechanisms are completely unknown. In vitro, cell proliferation and clonogenic survival were substantially inhibited after LicA treatment. LicA reduced HK2 expression, and both glucose consumption and lactate production in gastric cancer cells were significantly suppressed. Mechanistic investigations revealed that multiple signaling pathways including Akt, ERK and NF‑κB were suppressed by LicA. Further studies demonstrated that the inhibition of glycolysis by LicA was mainly attributed to the blockade of the Akt signaling pathway, and the suppression of glycolysis was substantially attenuated when Akt was exogenously overexpressed. In addition to the role in the inhibition of glycolysis, reduction in HK2 was confirmed to be involved in the induction of cell apoptosis. The apoptosis induced by LicA was substantially impaired after HK2 overexpression in gastric cancer cells. The in vivo experiment showed that MKN45 xenograft growth was markedly delayed after LicA treatment and HK2 expression in LicA‑treated tissues was markedly decreased. All of these data demonstrated that blockade of the Akt/HK2 pathway was the underlying mechanism required for LicA to exert its biological activities in glycolysis inhibition and apoptosis induction.

Topics: Animals; Apoptosis; Biomarkers, Tumor; Cell Proliferation; Chalcones; Gene Expression Regulation, Neoplastic; Glycolysis; Hexokinase; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Proto-Oncogene Proteins c-akt; Signal Transduction; Stomach Neoplasms; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Both phosphatidylinositol 3-kinase (PI3K)/AKT and mitogen activated protein kinase (MAPK) signaling cascades play an important role in cell proliferation, survival, angiogenesis, and metastasis of tumor cells. In the present report, we investigated the effects of licochalcone A (LA), a flavonoid extracted from licorice root, on the PI3K/AKT/mTOR and MAPK activation pathways in human gastric cancer BGC-823 cells. LA increased reactive oxygen species (ROS) levels, which is associated with the induction of apoptosis as characterized by positive Annexin V binding and activation of caspase-3, and cleavage of poly-ADP-ribose polymerase (PARP). Inhibition of ROS generation by N-acetylcysteine (NAC) significantly prevented LA-induced apoptosis. Interestingly, we also observed that LA caused the activation of ERK, JNK, and p38 MAPK in BGC-823 cells. The antitumour activity of LA-treated BGC-823 cells was significantly distinct in KM mice in vivo. All the findings from our study suggest that LA can interfere with MAPK signaling cascades, initiate ROS generation, induce oxidative stress and consequently cause BGC cell apoptosis.

Topics: Animals; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chalcones; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Humans; JNK Mitogen-Activated Protein Kinases; Mice; Mitogen-Activated Protein Kinases; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Signal Transduction; Stomach Neoplasms; Xenograft Model Antitumor Assays

In spite of cytoprotective and anti-inflammatory actions, conventional licorice extracts (c-lico) were limitedly used due to serious side effects of glycyrrhizin. As our group had successfully isolated special licorice extracts (s-lico) lowering troublesome glycyrrhizin, but increasing licochalcone A, we have compared anti-inflammatory, antioxidative, and cytoprotective actions of s-lico and c-lico against either in vitro or in vivo Helicobacter pylori infection.. RT-PCR and Western blot were performed to check anti-inflammatory action and electron spin resonance (ESR) and DCFDA spectroscopy to check antioxidative action. s-lico or c-lico was pretreated 1 hours before H. pylori infection on AGS cells. Interleukin-10 deficient mice inoculated H. pylori and followed with high salt containing pallet diets to produce H. pylori-associated chronic atrophic gastritis and gastric tumors, during which s-lico or c-lico-containing pellet diets were administered up to 24 weeks.. s-lico had fabulous efficacy on scavenging ROS which was further confirmed by DCFDA study and ESR measurement. The expressions of COX-2, iNOS, VEGF, and IL-8 were increased after H. pylori infection, of which levels were significantly decreased with s-lico in a dose-dependent manner. s-lico significantly ameliorated hypoxia-induced or H. pylori-induced angiogenic activities. s-lico significantly ameliorated H. pylori-induced gastric damages as well as gastritis. Our animal model showed significant development of gastric tumors including adenoma and dysplasia relevant to H. pylori infection, and s-lico administration significantly attenuated incidence of H. pylori-induced gastric tumorigenesis.. Special licorice extracts can be anticipating substance afforded significant attenuation of either H. pylori-induced gastritis or tumorigenesis based on potent antioxidative, anti-inflammatory, and antimutagenic actions.

Topics: Animals; Anti-Inflammatory Agents; Antineoplastic Agents; Carcinogenesis; Chalcones; Diet; Glycyrrhiza; Glycyrrhizic Acid; Helicobacter Infections; Male; Mice; Plant Extracts; Stomach Neoplasms; Treatment Outcome

The aim of this study was to determine the anticancer effects of seven licorice compounds in MKN-28, AGS, and MKN-45 gastric cancer cells and human gastric epithelium immortalized cells. We also explored the mechanism of action of licochalcone A (LCA), the most cytotoxic licorice compound, by analyzing its influence on cell cycle progression and apoptosis. The results indicated that LCA was the most cytotoxic licorice compound of those tested, and it inhibited gastric cancer cells growth in a dose-dependent manner, with an IC50 value of approximately 40μM. LCA affected gastric cancer cell viability by blocking cell cycle progression at the G2/M transition and inducing apoptosis. LCA treatment increased the expression of Rb and decreased the expression of cyclin A, cyclin B and MDM2 in MKN-28, AGS and MKN-45 cell lines. In addition, LCA-induced apoptosis by its effects on the expression of PARP, caspase-3, Bcl-2 and Bax. These data provide evidence that LCA has the potential to be used in the treatment of gastric cancer.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Blotting, Western; Cell Cycle; Cell Cycle Proteins; Cell Division; Cell Line; Cell Line, Tumor; Cell Proliferation; Chalcones; Dose-Response Relationship, Drug; G2 Phase; Glycyrrhiza; Humans; Inhibitory Concentration 50; Molecular Structure; Stomach Neoplasms