The receptor for advanced glycation end-products (RAGE) is a newly recognized factor regulating cancer cell invasion and metastasis. This study investigated the expression of RAGE in gastric carcinomas and its association with invasion and metastasis. Of eight gastric cancer cell lines examined, seven constitutively expressed RAGE messenger ribonucleic acid (mRNA), MKN45 being the exception. RAGE protein expression of MKN28 cells treated with RAGE antisense S-oligodeoxynucleotide was nine times less than that of sense S-oligodeoxynucleotide-treated cells. Growth of cells under RAGE antisense S-oligodeoxynucleotide treatment was not different from that seen under sense S-oligodeoxynucleotide treatment in MKN28 (a cell line producing high levels of RAGE) and MKN45 (a non-RAGE-expressing cell line). RAGE antisense S-oligodeoxynucleotide treatment suppressed the invasive activity of RAGE-positive MKN28 cells, as estimated by in vitro invasion assay. The number of MKN28 cells invading the type IV collagen-coated membrane under RAGE antisense S-oligodeoxynucleotide treatment was significantly lower than under RAGE sense S-oligodeoxynucleotide treatment (p<0.0001). In contrast, antisense and sense S-oligodeoxynucleotide-treated RAGE-negative MKN45 cells showed no difference. A wound-healing assay showed that no RAGE antisense S-oligodeoxynucleotide-treated MKN28 cells migrated into the scraped area, whereas sense S-oligodeoxynucleotide-treated cells showed many budding nests in the scraped area. Immunohistochemistry of gastric carcinoma tissue showed that 62 (65%) of the 96 cases examined were RAGE-positive and that poorly differentiated adenocarcinomas preferentially expressed RAGE protein (38/42, 90%) (p<0.0001). Strong RAGE immunoreactivity was also correlated with depth of invasion and lymph node metastasis (p<0.0001). RAGE-positive cancer cells tended to be distributed at the invasive front of primary tumours and were detected in all metastatic foci in lymph nodes. In contrast, a major RAGE ligand, amphoterin, was expressed in 82 (85%) of the 96 cases, regardless of histological type and disease progression. RAGE expression appears to be closely associated with invasion and metastasis in gastric cancer.

Cytokines may be crucially involved in the pathogenesis of inflammatory bowel diseases (IBD), but it remains controversial whether interferon (IFN)-gamma, a typical proinflammatory cytokine, is an essential mediator to cause the disorders. In the present study, IFN-gamma(-/-) and wild-type (WT) C57BL/6 mice were fed 2.5% dextran sodium sulphate (DSS) in drinking water for 7 days, in order to investigate DSS-induced intestinal inflammation. The DSS-treated WT mice exhibited a robust production of IFN-gamma in the gut, a remarkable loss of body weight, as well as high rate of mortality (60%). In striking contrast, IFN-gamma deficient mice did not develop DSS-induced colitis, as indicated by the maintenance of body weight and survival rate of 100%. Severe intestinal inflammation was demonstrated exclusively in WT animals in terms of the shortening of the bowel as well as the elevation of the disease activity index, myeloperoxidase (MPO) activity and serum haptoglobin level. Histological study of DSS-treated WT intestine revealed disruption of mucosal epithelium and massive infiltration of inflammatory cells, while the organ from IFN-gamma(-/-) mice remained virtually normal in appearance. Enzyme-linked immunosorbent assay (ELISA) analyses indicated abundant production of three chemokines, i.e. monokine induced by interferon-gamma (MIG), interferon-inducible protein 10 (IP-10) and monocyte chemoattractant protein-1 (MCP-1), in the DSS-irritated intestine of WT but not of IFN-gamma(-/-) mice. The present results demonstrate clearly that IFN-gamma plays indispensable roles in the initiation of DSS colitis, and some chemokines are produced in an IFN-gamma-dependent fashion.

No abstract

A major early event in papillary thyroid carcinogenesis is constitutive activation of the mitogen-activated protein kinase signaling pathway caused by alterations of a single gene, typically rearrangements of the RET and NTRK1 genes or point mutations in the BRAF and RAS genes. In childhood papillary thyroid cancer, regardless of history of radiation exposure, RET/PTC rearrangements are a major event. Conversely, in adult-onset papillary thyroid cancer among the general population, the most common molecular event is BRAF V600E point mutation, not RET/PTC rearrangements. To clarify which gene alteration, chromosome aberration, or point mutation preferentially occurs in radiation-associated adultonset papillary thyroid cancer, we have performed molecular analyses on RET/PTC rearrangements and BRAF V600E mutation in 71 papillary thyroid cancer cases among atomic bomb survivors (including 21 cases not exposed to atomic bomb radiation), in relation to radiation dose as well as time elapsed since atomic bomb radiation exposure. RET/PTC rearrangements showed significantly increased frequency with increased radiation dose (P trend = 0.002). In contrast, BRAF V600E mutation was less frequent in cases exposed to higher radiation dose (P trend < 0.001). Papillary thyroid cancer subjects harboring RET/PTC rearrangements developed this cancer earlier than did cases with BRAF V600E mutation (P = 0.03). These findings were confirmed by multivariate logistic regression analysis. These results suggest that RET/PTC rearrangements play an important role in radiation-associated thyroid carcinogenesis.

The importance of tumor necrosis factor (TNF)-alpha and the TNF receptor gene polymorphisms in the etipathogenesis of inflammatory bowel disease (IBD) has not been elucidated. DNA from peripheral blood samples was obtained from 124 patients with Crohn's disease (CD), 106 patients with ulcerative colitis (UC), and 111 unrelated healthy controls. We examined two single nucleotide polymorphisms (SNPs) of the TNF-alpha gene, TNF (-308 G/A and -238 G/A), an SNP of the TNF receptor superfamily member 1A gene, TNFRSF1A(also known as TNFR1), at codon 12 in exon 1 (CCA/CCG), and two SNPs of the 1B gene, TNFRSF1B (also known as TNFR2), (1466 A/G and 1493 C/T). There was a difference in the carrier frequency for haplotype AG (-308 A, -238 G) between UC patients and the controls (OR=4.76, 95% CI=1.53-14.74, P<0.01). We found a significant difference in carrier frequency for haplotype AT (1466 A, 1493 T) of the TNFRSF1B gene between CD patients and the controls (OR=2.13, 95% CI=1.08-4.21, P<0.05). The significance proved to be greater in CD patients with both internal and external fistula (OR=4.8, 95% CI=1.73-13.33, P<0.01), and in those who were poor responders ( n=22) to our treatments, which consisted of nutritional therapy, medical therapy and surgical therapy (OR=9.24, 95% CI=3.37-25.36, P<0.001). This study suggests that one of the genes responsible for UC may be the TNF gene, or an adjacent gene, and that TNFRSF1B gene polymorphisms contribute greatly to the increased onset risk of CD and to the disease behavior.

Gastric cancer is one of the most common human cancers and is the second most frequent cause of cancer-related death in the world. Serial analysis of gene expression (SAGE) is a powerful technique to allow genome-wide analysis of gene expression in a quantitative manner without prior knowledge of the gene sequences. SAGE on 5 samples of gastric cancer with different histology and clinical stages have created large SAGE libraries of gastric cancer that enable us to identify new cancer biomarkers. Commonly up-regulated genes in gastric cancer in comparison with normal gastric epithelia included CEACAM6, APOC1 and YF13H12. By comparing gene expression profiles of gastric cancers at early and advanced stages, several genes differentially expressed by tumor stage were also identified, including FUS, CDH17, COL1A1 and COL1A2, which should be novel genetic markers for high-grade malignancy. Regenerating gene type IV (REGIV) is one of the most up-regulated genes in a SAGE library of a scirrhous-type gastric cancer. In vitro studies using RegIVtransfected cells revealed that RegIV is secreted by cancer cells and inhibits apoptosis, suggesting that RegIV may serve as a novel biomarker and therapeutic target for gastric cancer. Production of RNA aptamers could be a useful approach to establish a detection system in blood. A custom-made array, named Ex-STO-MACHIP, consisting of 395 genes, including highly differentially expressed genes identified by our SAGE and other known genes related to carcinogenesis and chemosensitivity, is useful to study the molecular pathogenesis of gastric cancer and to obtain information about biological behavior and sensitivity to therapy in the clinical setting. Combined analyses of gene expression profile, genetic polymorphism and genetic instability will aid not only cancer detection, but also characterization of individual cancers and patients, leading to personalized medicine and cancer prevention.

No abstract

The importance of altered histone acetylation in gastrointestinal carcinogenesis, especially in relation to invasion and metastasis, is described. Histone acetylation and chromatin remodeling linked with CpG island methylation play a major role in epigenetic regulation of gene expression. Acetylation of histones through an imbalance of histone acetyltransferases and deacetylases disrupts nucleosome structure, which leads to DNA relaxation and subsequent increase in accessibility to transcription factors. The expression of acetylated histone H4 is reduced in a majority of gastric and colorectal cancers, indicating the low level of global histone acetylation in tumor cells. Moreover, reduced histone acetylation is significantly associated with depth of tumor invasion and nodal metastasis of gastrointestinal cancers. A histone deacetylase inhibitor, trichostatin A (TSA), induces growth arrest and apoptosis and suppresses invasion of cancer cells. Treatment with TSA, which is followed by increased histone acetylation in the promoters, induces the expression of many genes that are suppressors of invasion and metastasis, including tissue inhibitors of metalloproteinase and nm23H1/H2, in addition to negative cell cycle regulators and apoptosis-related molecules. Our approach, serial analysis of gene expression (SAGE), enabled us to identify a gene that is a novel candidate for a metastasis suppressor, whose expression is induced by histone acetylation. These findings suggest that, by modifying gene expression, histone deacetylation may participate not only in tumorigenesis but also in invasion and metastasis. Therefore, histone acetylation should be a promising target for cancer therapy, especially against invasive and metastatic disease, but also for cancer prevention.