DNA methylation of GHSR, GNG4, HOXD9 and SALL3 is a common epigenetic alteration in thymic carcinoma.

Thymic epithelial tumors comprise thymoma, thymic carcinoma and neuroendocrine tumors of the thymus. Recent studies have revealed that the incidence of somatic non­synonymous mutations is significantly higher in thymic carcinoma than in thymoma. However, limited information is currently available on epigenetic alterations in these types of cancer. In this study, we thus performed genome­wide screening of aberrantly methylated CpG islands in thymoma and thymic carcinoma using Illumina HumanMethylation450 K BeadChip. We identified 92 CpG islands significantly hypermethylated in thymic carcinoma in relation to thymoma and selected G protein subunit gamma 4 (GNG4), growth hormone secretagogue receptor (GHSR), homeobox D9 (HOXD9) and spalt like transcription factor 3 (SALL3), which are related to cancer. We examined the promoter methylation of 4 genes in 46 thymic epithelial tumors and 20 paired thymus tissues using bisulfite pyrosequencing. Promoter methylation was significantly higher in thymic carcinoma than in thymoma and revealed a high discrimination between thymic carcinoma and thymoma in all 4 genes. Promoter methylation was higher in thymic carcinoma than in the thymus. No significant differences were observed in the promoter methylation of GNG4, HOXD9, or SALL3 between thymoma and the thymus. The promoter methylation of the 4 genes was not significantly higher in advanced­stage tumors than in early­stage tumors in all thymic epithelial tumors. Among the 4 genes, relapse­free survival was significantly worse in tumors with a higher DNA methylation than in those with a lower DNA methylation in all thymic epithelial tumors. Moreover, relapse­free survival was significantly worse in thymomas with a higher DNA methylation of HOXD9 and SALL3 than in those with a lower DNA methylation. On the whole, the findings of this study indicated that the promoter methylation of cancer­related genes was significantly higher in thymic carcinoma than in thymoma and the thymus. This is a common epigenetic alteration of high diagnostic value in thymic carcinoma and may be involved in the carcinogenesis of thymic carcinoma. However, epigenetic alterations in the 3 genes, apart from GHSR, are not involved in the tumorigenesis of thymoma.

Putative Effect of Spirulina Extract on Enzyme Activities Participating in Lipid and Carbohydrate Digestion Processes.

Excessive calorie intake is generally accepted as a primary cause of metabolic syndrome, and therefore a well-balanced diet and moderate exercise can be expected to be the most effective measures to avoid the disorder of energy utilization and storage. Furthermore, as any other way to improve the disorder of energy balance, it may be effective to delay and lower the digestion and/or absorption of energy sources, lipids, and carbohydrates. As a primary screening of effective substances to delay and lower the digestion and absorption processes among natural materials, the protein-deprived extract was prepared from blue-green algae Spirulina platensis, and the effect of this extract on lipase and α-glucosidase activities was examined. The extract was shown to inhibit lipase activity but not α-glucosidase activity, thus proposing the possibility that the extract prevented the postprandial elevation of blood triglyceride (TG) levels as a result of reducing the digestion and absorption of lipids in the intestinal tract. Therefore, it seems possible to speculate that nonprotein components of Spirulina may be able to effectively improve the disorder of energy balance as a consequence of suppressing the excessive intake of calories by reducing the absorption of lipids in patients with metabolic syndrome.

Lotus Root Extract Stimulates BDNF Gene Expression Through Potential Mechanism Depending on HO-1 Activity in C6 Glioma Cells.

Polyphenolic compounds have been suggested to be involved in the preservation of neural function via the production of neurotrophic factors in the brain. The nonedible joint part of lotus root (a rhizome of Nelumbo nucifera) has been reported to contain large amounts of polyphenolic compounds and, therefore, is expected to improve neural function by stimulating the production of brain-derived neurotrophic factor (BDNF) in glial cells. The effect of the aqueous extract prepared from the joint part of lotus root on BDNF gene expression was examined in C6 glioma cells as an in vitro model. This extract was shown to increase BDNF messenger ribonucleic acid (mRNA) levels to the elevation of HO-1 mRNA levels in the glioma cells, but failed to cause the elevation of BDNF mRNA levels in the cells pretreated with a HO-1 antisense oligodeoxynucleotide (ODN) or an HO-1 enzyme inhibitor zinc protoporphyrin (ZnPP). These findings strongly suggest that the aqueous extract prepared from the nonedible joint part of lotus root might be able to stimulate BDNF gene expression by enhancing HO-1 activity in the glioma cells, proposing the possibility that the joint part of lotus root might potentially improve neural function through the stimulation of BDNF production in glial cells.

Suppressive effect of Okara on intestinal lipid digestion and absorption in mice ingesting high-fat diet.

Soymilk residue Okara is paid attention as a low-calorie foodstuff effective for the amelioration of obesity, and expected to have the potential ability to reduce calorie intake by suppressing the digestion and absorption of high-calorie nutrients in the intestinal tract. Then, the direct effect of Okara extract on lipase activity was examined, and this extract was shown to inhibit the enzyme activity. On the other hand, the spray-dried powder of Okara extract was suspended in a drinking water and given to mice fed with a high-fat diet. Consequently, Okara suspension was shown to reduce triglyceride (TG) levels in the blood, thus suggesting that Okara ingestion could suppress the digestion and absorption of lipids through the inhibition of lipase activity in the intestinal tract. Therefore, Okara is speculated to have the potential ability to prevent the excess intake of calories, thereby being effective and useful for the amelioration of metabolic syndrome.

Frequent silencing of RASSF1A by DNA methylation in thymic neuroendocrine tumours.

OBJECTIVES: Aberrant methylation of promoter CpG islands (CGIs) of tumour suppressor genes is a common epigenetic mechanism underlying cancer pathogenesis. The methylation patterns of thymic tumours have not been studied in detail since such tumours are rare. Herein, we sought to identify genes that could serve as epigenetic targets for thymic neuroendocrine tumour (NET) therapy. MATERIALS AND METHODS: Genome-wide screening for aberrantly methylated CGIs was performed in three NET samples, seven thymic carcinoma (TC) samples, and eight type-B3 thymoma samples. The methylation status of thymic epithelial tumours (TETs) samples was validated by pyrosequencing in a larger cohort. The expression status was analysed by quantitative polymerase chain reaction (PCR) and immunohistochemistry. RESULTS: We identified a CGI on a novel gene, RASSF1A, which was strongly hypermethylated in NET, but not in thymic carcinoma or B3 thymoma. RASSF1A was identified as a candidate gene statistically and bibliographically, as it showed frequent CGI hypermethylation in NET by genome-wide screening. Pyrosequencing confirmed significant hypermethylation of a RASSF1A CGI in NET. Low-grade NET tissue was more strongly methylated than high-grade NET. Quantitative PCR and immunohistochemical staining revealed that RASSF1A mRNA and protein expression levels were negatively regulated by DNA methylation. CONCLUSIONS: RASSF1A is a tumour suppressor gene epigenetically dysregulated in NET. Aberrant methylation of RASSF1A has been reported in various tumours, but this is the first report of RASSF1A hypermethylation in TETs. RASSF1A may represent an epigenetic therapeutic target in thymic NET.

Soy Pulp Extract Inhibits Angiotensin I-Converting Enzyme (ACE) Activity In Vitro: Evidence for Its Potential Hypertension-Improving Action.

Soy pulp, called "okara" in Japanese, is known as a by-product of the production of bean curd (tofu), and expected to contain a variety of biologically active substances derived from soybean. However, the biological activities of okara ingredients have not yet been fully understood, and the effectiveness of okara as a functional food seems necessary to be further evaluated. Then the effect of okara extract on angiotensin I-converting enzyme (ACE) activity was examined in vitro, and the extract was shown to cause the inhibition of ACE activity in a manner depending on its concentration. Kinetic analysis indicated that this enzyme inhibition was accompanied by an increase in the Km value without any change in Vmax. Further studies suggested that putative inhibitory substances contained in the extract might be heat stable and dialyzable, and recovered mostly in the peptide fraction obtained by a spin-column separation and a high performance liquid chromatography (HPLC) fractionation. Therefore, the extract was speculated to contain small-size peptides responsible for the inhibitory effect of okara extract on ACE activity, and could be expected to improve the hypertensive conditions by reducing the production of hypertensive peptide.

Fermented Brown Rice Extract Stimulates BDNF Gene Transcription in C6 Glioma Cells: Possible Connection with HO-1 Expression.

Fermented brown rice with Aspergillus oryzae, designated as FBRA, is known to be commercially available dietary fiber-rich food, which is appreciated as prebiotics to improve intestinal microflora, and also shown to contain various biologically active substances including polyphenolic compounds. On the other hand, polyphenolic compounds have been suggested to stimulate the expression of brain-derived neurotrophic factor (BDNF) gene in connection with the expression of heme oxidase-1 (HO-1) gene in glial cells, thus resulting in the augmentation of BDNF production in the brain, thereby being anticipated to have a putative effect on the brain function. Then, the effect of FBRA extract on HO-1 and BDNF messenger ribonucleic acid (mRNA) levels in C6 glioma cells was examined, and the extract was shown to stimulate both HO-1 and BDNF gene transcription in the glioma cells. Further studies showed that the stimulatory effect of FBRA extract on BDNF gene transcription was almost completely suppressed by silencing HO-1 gene expression with an HO-1 antisense oligodeoxynucleotide and also inhibiting HO-1 activity with an inhibitor zinc protoporphyrin, thus suggesting that FBRA might have a potential ability to induce BDNF gene expression through HO-1 activity in glial cells.