Inhibitory Effects of Saururus chinensis Extract on Receptor for Advanced Glycation End-Products-Dependent Inflammation and Diabetes-Induced Dysregulation of Vasodilation.

Advanced glycation end-products (AGEs) and the receptor for AGEs (RAGE) are implicated in inflammatory reactions and vascular complications in diabetes. Signaling pathways downstream of RAGE are involved in NF-κB activation. In this study, we examined whether ethanol extracts of Saururus chinensis (Lour.) Baill. (SE) could affect RAGE signaling and vascular relaxation in streptozotocin (STZ)-induced diabetic rats. Treatment with SE inhibited AGEs-modified bovine serum albumin (AGEs-BSA)-elicited activation of NF-κB and could compete with AGEs-BSA binding to RAGE in a dose-dependent manner. Tumor necrosis factor-α (TNF-α) secretion induced by lipopolysaccharide (LPS)-a RAGE ligand-was also reduced by SE treatment in wild-type Ager+/+ mice as well as in cultured peritoneal macrophages from Ager+/+ mice but not in Ager-/- mice. SE administration significantly ameliorated diabetes-related dysregulation of acetylcholine-mediated vascular relaxation in STZ-induced diabetic rats. These results suggest that SE would inhibit RAGE signaling and would be useful for the improvement of vascular endothelial dysfunction in diabetes.

RAGE signaling antagonist suppresses mouse macrophage foam cell formation.

The engagement of the receptor for advanced glycation end-products (receptor for AGEs, RAGE) with diverse ligands could elicit chronic vascular inflammation, such as atherosclerosis. Binding of cytoplasmic tail RAGE (ctRAGE) to diaphanous-related formin 1 (Diaph1) is known to yield RAGE intracellular signal transduction and subsequent cellular responses. However, the effectiveness of an inhibitor of the ctRAGE/Diaph1 interaction in attenuating the development of atherosclerosis is unclear. In this study, using macrophages from Ager+/+ and Ager-/- mice, we validated the effects of an inhibitor on AGEs-RAGE-induced foam cell formation. The inhibitor significantly suppressed AGEs-RAGE-evoked Rac1 activity, cell invasion, and uptake of oxidized low-density lipoprotein, as well as AGEs-induced NF-κB activation and upregulation of proinflammatory gene expression. Moreover, expression of Il-10, an anti-inflammatory gene, was restored by this antagonist. These findings suggest that the RAGE-Diaph1 inhibitor could be a potential therapeutic drug against RAGE-related diseases, such as chronic inflammation and atherosclerosis.

In vitro anticancer effects of a RAGE inhibitor discovered using a structure-based drug design system.

Receptor for advanced glycation end-products (RAGE) is a pattern recognition receptor implicated in the pathogenesis of certain types of cancer. In the present study, papaverine was identified as a RAGE inhibitor using the conversion to small molecules through optimized-peptide strategy drug design system. Papaverine significantly inhibited RAGE-dependent nuclear factor κ-B activation driven by high mobility group box-1, a RAGE ligand. Using RAGE- or dominant-negative RAGE-expressing HT1080 human fibrosarcoma cells, the present study revealed that papaverine suppressed RAGE-dependent cell proliferation and migration dose-dependently. Furthermore, papaverine significantly inhibited cell invasion. The results of the present study suggested that papaverine could inhibit RAGE, and provided novel insights into the field of RAGE biology, particularly anticancer therapies.

The rs6983267 SNP is associated with MYC transcription efficiency, which promotes progression and worsens prognosis of colorectal cancer.

BACKGROUND: The oncogenic single nucleotide polymorphism rs6983267, located on 8q24.21, may affect copy number aberrations and/or expression profiles in colorectal cancer (CRC). We investigated the role of this single nucleotide polymorphism in the clinical outcome of CRC. METHODS: Array comparative genomic hybridization (aCGH) and oligomicroarrays were performed on cancer cells from 157 primary CRC tissues. Expression profiles were analyzed by means of extraction expression module (EEM) analyses. Mutations in TP53, KRAS, and BRAF and microsatellite instability were also examined in 107 of the 157 cases. RESULTS: aCGH analysis revealed two clusters; more frequent genomic copy number alteration (CNA) was observed in the 89 cases in cluster B than in the 18 cases in cluster A. The average CNA was higher in samples containing the major allele (GT/TT) of rs6983267 than in those containing the minor allele (GG). Additionally, MYC expression was the highest in samples containing the GG allele (n = 18), followed by the GT and TT alleles (n = 41 and 48, respectively). EEM analysis revealed dominant up-regulation of MYC in samples containing the minor allele. Moreover, the presence of the minor allele in a MYC-positive, CNA-negative context predicted a poorer prognosis than the presence of the major allele in a MYC-negative, CNA-positive context in CRC. CONCLUSIONS: The presence of the minor allele of rs6983267 at 8q24.21 worsened the prognosis of CRC through up-regulation of MYC transcription. Furthermore, progression of CRC may require global CNA in the presence of the major allele and with lack of MYC transcription.