Ji Ye Lim

Intestinal anti-inflammatory activity of Sasa quelpaertensis leaf extract by suppressing lipopolysaccharide-stimulated inflammatory mediators in intestinal epithelial Caco-2 cells co-cultured with RAW 264.7 macrophage cells

BACKGROUND/OBJECTIVES Inflammatory bowel disease (IBD), including Crohns disease and ulcerative colitis, involves chronic inflammation of the gastrointestinal tract. Previously, Sasa quelpaertensis leaves have been shown to mediate anti-inflammation and anti-cancer effects, although it remains unclear whether Sasa leaves are able to attenuate inflammation-related intestinal diseases. Therefore, the aim of this study was to investigate the anti-inflammatory effects of Sasa quelpaertensis leaf extract (SQE) using an in vitro co-culture model of the intestinal epithelial environment. MATERIALS/METHODS An in vitro co-culture system was established that consisted of intestinal epithelial Caco-2 cells and RAW 264.7 macrophages. Treatment with lipopolysaccharide (LPS) was used to induce inflammation. RESULTS Treatment with SQE significantly suppressed the secretion of LPS-induced nitric oxide (NO), prostaglandin E2 (PGE2), IL-6, and IL-1β in co-cultured RAW 264.7 macrophages. In addition, expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and tumor necrosis factor (TNF)-α were down-regulated in response to inhibition of IκBα phosphorylation by SQE. Compared with two bioactive compounds that have previously been identified in SQE, tricin and P-coumaric acid, SQE exhibited the most effective anti-inflammatory properties. CONCLUSIONS SQE exhibited intestinal anti-inflammatory activity by inhibiting various inflammatory mediators mediated through nuclear transcription factor kappa-B (NF-kB) activation. Thus, SQE has the potential to ameliorate inflammation-related diseases, including IBD, by limiting excessive production of pro-inflammatory mediators.

d-Xylose suppresses adipogenesis and regulates lipid metabolism genes in high-fat diet–induced obese mice

D-Xylose, a natural pentose, has been reported to reduce postprandial glucose levels, although its effect on lipid metabolism has not been investigated. Therefore, this study hypothesized that d-xylose, as an alternative sweetener, suppresses adipogenesis and lipid metabolism by regulating blood lipid profiles, blood glucose levels, and related gene expression in high-fat diet (HFD)-induced obese mice. Mice were fed a normal diet, a 60% HFD diet, or an HFD with 5% or 10% of the total sucrose content supplemented with d-xylose (Xylo 5 and Xylo 10 diets, respectively). Weight gain, food intake, and serum lipid levels for each group were measured. After 12 weeks, histopathology of liver sections and assays of gene expression related to adipogenesis and lipid metabolism in visceral fat and liver tissues were analyzed. Body weight gain; fasting blood glucose levels; weights of subcutaneous and visceral adipose tissues; and serum biochemical markers, including total cholesterol and low-density lipoprotein cholesterol, low-/high-density lipoprotein, and total cholesterol/high-density lipoprotein, were significantly lowered in the Xylo 5 and Xylo 10 groups. In addition, d-xylose supplementation resulted in the down-regulation of adipogenesis-related genes, including sterol regulatory element-binding protein 1C, fatty acid synthase, adipocyte protein 2, and CCAAT/enhancer-binding protein α in visceral adipose tissues. Histopathologically, Xylo 5 and Xylo 10 supplementation reduced HFD-induced fat accumulation in the liver and decreased expressions of fatty acid synthase and peroxisome proliferator-activated receptor γ. D-Xylose supplementation also enhanced lipid oxidation by increasing expressions of carnitine palmitoyltransferase 1A; cytochrome P450, family 4, subfamily a, polypeptide 10; and acyl-CoA oxidase. In conclusion, our finding suggests that d-xylose may help prevent or attenuate the progression of obesity-related metabolic disorders by alleviating adipogenesis and dyslipidemia and improving lipid oxidation.

Sasa quelpaertensis Leaf Extract Inhibits Colon Cancer by Regulating Cancer Cell Stemness in Vitro and in Vivo.

A rare subpopulation of cancer cells, termed cancer stem cells (CSCs), may be responsible for tumor relapse and resistance to conventional chemotherapy. The development of a non-toxic, natural treatment for the elimination of CSCs is considered a strategy for cancer treatment with minimal side effects. In the present study, the potential for Sasa quelpaertensis leaf extract (SQE) and its two bioactive compounds, tricin and p-coumaric acid, to exert anti-CSC effects by suppressing cancer stemness characteristics were evaluated in colon cancer cells. CD133+CD44+ cells were isolated from HT29 and HCT116 cell lines using flow-activated cell sorting (FACs). SQE treatment was found to significantly suppress the self-renewal capacity of both cell lines. SQE treatment was also associated with the down-regulation of β-catenin and phosphorylated GSK3β, while significantly enhancing cell differentiation by up-regulating CK20 expression and blocking the expression of several stem cell markers, including DLK1, Notch1, and Sox-2. In vivo, SQE supplementation suppressed tumor growth in a xenograft model by down-regulating stem cell markers and β-catenin as well as HIF-1α signaling. Compared with two bioactive compounds of SQE, SQE exhibited the most effective anti-CSC properties. Taken together, these results provide evidence that SQE inhibits colon cancer by regulating the characteristics of CSCs.

β-Carotene inhibits neuroblastoma cell invasion and metastasis in vitro and in vivo by decreasing level of hypoxia-inducible factor-1α.

Neuroblastoma is the most prevalent extracranial solid tumor in childhood and has poor clinical outcome due to its high potential for metastasis. Consequently, an understanding of the mechanisms that modulate cancer cell invasion, migration and metastasis is important for the development of more effective chemotherapeutic agents. While β-carotene is a vitamin A precursor that has been shown to exert antioxidant and anticancer effects, the anti-metastatic effects of β-carotene on neuroblastoma cells remain poorly understood. The aim of the present study was to investigate the anti-metastatic effects of β-carotene on highly malignant SK-N-BE(2)C neuroblastoma cells in vitro and in vivo. Treatment of SK-N-BE(2)C cells with β-carotene was found to attenuate the migratory and invasive capabilities of the cells. In addition, the enzymatic activity and expression of matrix metalloproteinase (MMP)-2 was suppressed following β-carotene treatment under both normoxia and hypoxia. To induce metastasis, immunodeficient nude mice were injected with SK-N-BE(2)C cells via the tail vein in vivo. The incidence of liver metastasis and mean tumor volume in mice that were administered β-carotene was decreased compared to controls. Furthermore, mRNA levels of MMPs, membrane-type (MT) 2 MMP and tissue inhibitors of metalloproteinases in liver tumor tissues were also lower following β-carotene treatment. Level of hypoxia-inducible factor-1α (HIF-1α) and its downstream targets, vascular endothelial growth factor and glucose transporter 1 (GLUT1), were lower both in vitro and in vivo following β-carotene treatment. In conclusion, the present study provides the first evidence that β-carotene may represent an effective chemotherapeutic agent by regulating the invasion and metastasis of neuroblastoma via HIF-1α.

Β-carotene inhibits neuroblastoma tumorigenesis by regulating cell differentiation and cancer cell stemness.

Neuroblastoma (NB) is the most common extracranial solid cancer in young children and malignant NB cells have been shown to possess cancer stem cell (CSC) characteristics. Thus, the successful elimination of CSCs represents a strategy for developing an effective preventive and chemotherapeutic agent. CSCs are characterized by differentiation and tumorigenicity. β-Carotene (BC) has been associated with many anticancer mechanisms, although the efficacy of BC on CSCs remains unclear. In the present study, the effects of BC on tumor cell differentiation and tumorigenicity was investigated using a xenograft model. Mice were pretreated with BC for 21 days, then received a subcutaneous injection of SK-N-BE(2)C cells. Both tumor incidence and tumor growth were significantly inhibited for mice that received BC supplementation compared to the control group. Treatment with BC has also been shown to induce tumor cell differentiation by up-regulating differentiation markers, such as vimentin, peripherin, and neurofilament. Conversely, BC treatment has been shown to significantly suppress tumor stemness by down-regulating CSC markers such as Oct 3/4 and DLK1. BC treatment also significantly down-regulated HIF1-α expression and its downstream target, vascular endothelial growth factor (VEGF). Taken together, these results suggest that BC is a potential chemotherapeutic reagent for the treatment of NB, and mediates this effect by regulating the differentiation and stemness of CSCs, respectively.

Sasa quelpaertensis leaf extract suppresses dextran sulfate sodium–induced colitis in mice by inhibiting the proinflammatory mediators and mitogen-activated protein kinase phosphorylation

Sasa quelpaertensis leaves exert anti-inflammatory and anticarcinogenic effects, although it remains unclear whether these leaves can suppress inflammation-related intestinal diseases. This study hypothesized that Sasa quelpaertensis leaf extract (SQE) exerts a protective effect against inflammation in a dextran sulfate sodium (DSS)-induced colitis mouse model. Therefore, colon tissues of DSS-induced colitis mice that were treated with SQE were assayed for levels of proinflammatory markers, mitogen-activated protein kinase signaling, and activation of nuclear factor κB. For this purpose, mice were pretreated with SQE (100 mg/kg or 300 mg/kg body weight) by gavage for a 2-week period. Mice then received either SQE or sulfasalazine (100 mg/kg body weight) with 2.5% DSS in drinking water for 7 days twice daily and 7 days of tap water ad libitum between DSS treatment. Treatment with SQE was found to attenuate the severity of DSS-induced colitis, as assessed by disease activity index scores, shrinkage of colon length, and histopathologic changes. SQE reduced DSS-induced proliferation in distal colon tissues. It also significantly suppressed levels of tumor necrosis factor-α in serum and colon tissues, nitric oxide synthase, cyclooxygenase, and levels of phosphorylated c-Jun N-terminal kinases, p38, extracellular-signal-regulated kinases 1/2, and IκBα in colon tissues. To our knowledge, this is the first study to demonstrate that SQE supplementation can exert an anti-inflammatory effect on experimental chronic colitis.

Xylobiose, an Alternative Sweetener, Ameliorates Diabetes-Related Metabolic Changes by Regulating Hepatic Lipogenesis and miR-122a/33a in db/db Mice

Type 2 diabetes is a major public health concern worldwide. Xylobiose (XB) consists of two molecules of d-xylose and is a major disaccharide in xylooligosaccharides that are used as prebiotics. We hypothesized that XB could regulate diabetes-related metabolic and genetic changes via microRNA expression in db/db mice. For six weeks, C57BL/KsJ-db/db mice received 5% XB as part of the total sucrose content of their diet. XB supplementation improved glucose tolerance with reduced levels of OGTT AUC, fasting blood glucose, HbA1c, insulin, and HOMA-IR. Furthermore, XB supplementation decreased the levels of total triglycerides, total cholesterol, and LDL-C. The expression levels of miR-122a and miR-33a were higher and lower in the XB group, respectively. In the liver, expressions of the lipogenic genes, including, fatty acid synthase (FAS), peroxisome proliferator activated receptor γ (PPARγ), sterol regulatory element-binding protein-1C (SREBP-1C), sterol regulatory element-binding protein-2 (SREBP-2), acetyl-CoA carboxylase (ACC), HMG-CoA reductase (HMGCR), ATP-binding cassette transporter G5/G8 (ABCG5/8), cholesterol 7 alpha-hydroxylase (CYP7A1), and sterol 12-alpha-hydroxylase (CYP8B1), as well as oxidative stress markers, including superoxide dismutase 1 (SOD1), superoxide dismutase 2 (SOD2), glutathione peroxidase (GPX), and catalase, were also regulated by XB supplementation. XB supplementation inhibited the mRNA expressions levels of the pro-inflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, interleukin (IL)-6, and monocyte chemoattractant protein (MCP)-1, as well as phosphorylation of c-Jun N-terminal kinase/stress activated protein kinase (JNK/SAPK), p38 mitogen-activated protein kinases (MAPK), and extracellular signal-regulated kinases 1/2 (ERK1/2). These data demonstrate that XB exhibits anti-diabetic, hypolipogenic, and anti-inflammatory effects via regulation of the miR-122a/33a axis in db/db mice.

Enzymatic Process for High-Yield Turanose Production and Its Potential Property as an Adipogenesis Regulator.

Turanose is a sucrose isomer naturally existing in honey and a promising functional sweetener due to its low glycemic response. In this study, the extrinsic fructose effect on turanose productivity was examined in Neisseria amylosucrase reaction. Turanose was produced, by increasing the amount of extrinsic fructose as a reaction modulator, with high concentration of sucrose substrate, which resulted in 73.7% of production yield. In physiological functionality test, lipid accumulation in 3T3-L1 preadipocytes in the presence of high amounts of pure glucose was attenuated by turanose substitution in a dose-dependent manner. Turanose treatments at concentrations representing 50%, 75%, and 100% of total glucose concentration in cell media significantly reduced lipid accumulation by 18%, 35%, and 72%, respectively, as compared to controls. This result suggested that turanose had a positive role in controlling adipogenesis, and enzymatic process of turanose production has a potential to develop a functional food ingredient for controlling obesity and related chronic diseases.

β-carotene Regulates the Murine Liver Microenvironment of a Metastatic Neuroblastoma.

Background: The anticarcinogenic effects of β-carotene (BC) have been well-characterized. However, the effect of BC on the microenvironment of a tumor remains to be investigated, especially since normal tissue proximal to a tumor has been shown to play a critical role in cancer progression and metastasis. For young children, neuroblastoma (NB) is the most common extracranial solid cancer diagnosed. Therefore, in the present study, effect of BC on the murine liver microenvironment of a metastatic NB was evaluated. Methods: Using a mouse model, three experimental groups were established: control mice, mice receiving an injection of SK-N-BE(2)C cells (TC), and mice receiving an injection of SK-N-BE(2)C cells plus 2 mg/kg BC twice a week (BC). Eight weeks after the injection of tumor, liver tissues were collected from all three groups, with the TC and BC tissues collected proximal to the metastatic NBs. Results: Compared to control tissues, BC tissues exhibited lower levels of proliferation, apoptosis, and metastasis. Assays for these processes included the detection of lower levels of proliferating cell nuclear antigen (PCNA), Bax, MMP2, and MMP9. In addition, higher levels of Bcl-2 were detected. Fewer cells undergoing an epithelial mesenchymal transition (EMT) were also observed in the BC group. Furthermore, BC tissues were associated with reduced expression of cancer stem cell marker, delta-like 1 homologue (DLK1), lower levels of VEGF mRNA and fewer CD31-positive cells. Finally, The antioxidant capability of the tumor microenvironment for the BC group was enhanced with higher expression levels of glutathione peroxidase (GPX), catalase, and manganese superoxide (MnSOD) detected. Conclusion: These data suggest that BC affects the microenvironment of a tumor, and this enhances the anti-cancer effects of BC.

Effects of plant-based Korean food extracts on lipopolysaccharide-stimulated production of inflammatory mediators in vitro

BACKGROUND/OBJECTIVES The traditional Korean diet is plant-based and rich in antioxidants. Previous studies have investigated the potential health benefits of individual nutrients of Korean foods. However, the cumulative effects of a Korean diet on inflammation remain poorly understood. Therefore, the aim of this study was to investigate the anti-inflammatory effects of a plant-based Korean diet. MATERIALS/METHODS Using data from the Fifth Korean National Health and Nutrition Examination Survey, 75 individual plant food items were selected which represent over 1% of the total diet intake of the Korean diet. These items were classified into ten different food groups, and the vegetable (Veg) and fruit (Fruit) groups were studied based on their high antioxidant capacity. For comparison, a mixture of all ten groups (Mix) was prepared. To produce a model of inflammation with which to test these Veg, Fruit, and Mix plant-based Korean food extracts (PKE), RAW264.7 macrophages were treated with lipopolysaccharide (LPS). RESULTS Levels of nitric oxide (NO) and prostaglandin E2 (PGE2), as well as protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were found to be lower following PKE treatment. Furthermore, PKE treatment was found to suppress tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) via the nuclear transcription factor kappa-B (NF-κB) signaling pathway. Overall, the Mix group exhibited the greatest anti-inflammatory effects compared with Veg and Fruit PKE group. CONCLUSIONS Inhibition of LPS-induced pro-inflammatory mediators by the PKE tested was found to involve an inhibition of NF-kB activation. Moreover, PKE tested have the potential to ameliorate various inflammation-related diseases by limiting the excessive production of pro-inflammatory mediators.