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.

BackgroundOral human papillomavirus (HPV) infection is associated with oral cancer development. However, few epidemiologic investigations have focused on oral HPV prevalence in healthy individuals. The objective of this study was to provide updated information regarding oral HPV prevalence in patients without oral cancer worldwide.MethodsWe systematically reviewed 29 studies reporting the prevalence of oral HPV infection that included 22,756 subjects (10,124 males, 12,623 females, and nine unknown gender; age range 2 - 89 years) and were published from January 2012 to June 2015.ResultsThe prevalence of overall HPV, low-risk type HPV, high-risk type HPV, and HPV16 in the reported cases was 5.5%, 2.2%, 2.7%, and 1.0%, respectively. The prevalence of overall HPV was considerably higher in males who had sex with males (12.2%) as compared to heterosexual males (4.7%) and females (2.9%). A meta-analysis was performed to elucidate significant risk factors for oral HPV infection, which revealed a significant statistical association for oral sex and smoking with oral HPV infection (odds ratio (OR): 1.90, 95% confidence interval (CI): 1.51 - 2.39, P < 0.0001; OR: 2.13, 95% CI: 1.32 - 3.43, P = 0.002).ConclusionsOur findings suggest that sexual behavior and smoking are importantly related to oral HPV infection in healthy individuals.

Abstractp63 is a member of the p53 family and regulates crucial events in the formation of epithelial structures, but the role of p63 in tumor is unclear. We found that Snail-induced epithelialto-mesenchymal transition (EMT) is accompanied by downregulation of p63 in human squamous cell carcinomas (SCC). #Np63A is the predominantly expressed p63 isoform in SCC cells. DNp63 promoter activity required a CAAT/enhancer binding protein (C/EBP) binding element and was reduced remarkably by Snail. Down-regulation of #Np63A and reduction of C/EBPA were observed in EMT phenotype cells, which exhibited invasive activity in vitro. p63 knockdown in cells enhanced invasive activity in the presence of E-cadherin. Conversely, forced expression of #Np63A blocked invasive activity of cells with the EMT phenotype. These findings indicate that Snail down-regulates #Np63A, leading to acquisition of the invasive phenotype by SCC. The invasive activity caused by down-regulation of #Np63A does not require down-regulation of E-cadherin.

Cells sorted from head and neck cancers on the basis of their high expression of CD44 have high potency for tumor initiation. These cells are also involved in epithelial to mesenchymal transition (EMT) and we have previously reported that cancer stem cells (CSCs) exist as two biologically distinct phenotypes. Both phenotypes are CD44 high but one is also ESA high and maintains epithelial characteristics, the other is ESA low , has mesenchymal characteristics and is migratory. Examining CD44-regulated signal pathways in these cells we show that CD44, and also RHAMM, act to inhibit phosphorylation of glycogen synthase kinase 3b (GSK3b). We show that inhibitory phosphorylation reduces the formation of both ''tumor spheres'' and ''holoclone'' colonies, functional indicators of stemness. GSK3b inhibition also reduces the expression of stem cell markers such as Oct4, Sox2, and Nanog and upregulates expression of the differentiation markers Calgranulin B and Involucrin in the CD44 high /ESA high cell fraction. Transition of CSCs out of EMT and back to the epithelial CSC phenotype is induced by GSK3b knockdown. These results indicate that GSK3b plays a central role in determining and maintaining the phenotypes and behavior of CSCs in vitro and are likely to be involved in controlling the growth and spread of tumors in vivo.

Key words: DNA methylation, gastric carcinoma, MGMTN-methyl-NЈ-nitro-N-nitrosoguanidine (MNNG) and N-methyl-N-nitrosourea (MNU) have been shown to induce gastric carcinoma at a high frequency in rats and mice when given in their drinking water. 1,2 MNNG and MNU produce O 6 -methylguanine, which mispairs with thymine during replication, resulting in conversion of a guanine-cytosine pair to an adenine-thymine pair if the adduct is not removed. 3,4 The O 6 -methylguanine-DNA methyltransferase, MGMT, is a DNA repair gene that removes mutagenic and cytotoxic adducts from the O 6 position of guanine induced by alkylating agents such as MNNG and MNU. 5 Therefore, inactivation of the MGMT gene can lead to G to A mutation. In fact, MNU has been shown to induce tumors such as thymic lymphomas and lung adenomas MGMT knockout mice. 6 Epigenetic alterations, in addition to multiple genetic abnormalities, are deeply involved in the genesis and progression of human cancers. Methylation status of the CpG island in promoter regions is an important determinant of gene expression. Aberrant hypermethylation of the CpG island is associated with silencing of tumor suppressor genes in various tumors. Promoter hypermethylation and reduced MGMT expression has been found in some primary human carcinomas. [7][8][9] Data have also indicated that wild-type p53 may negatively regulate basal MGMT promoter activity. in vitro and in vivo studies have shown that induction of MGMT in the presence of DNAdamaging agents involves p53. 10,11 Transfection of MGMT promoter together with a p53-expression vector in both p53 knockout and p53 wild-type cells significantly reduced MGMT promoter activity. 10,12 No study, however, has been conducted to clarify the role and mechanism of MGMT alteration in gastric carcinoma.We examined DNA methylation of CpG islands of the MGMT gene by methylation specific PCR in 26 primary gastric carcinoma tissues and 8 gastric carcinoma cell lines and compared the results with levels of MGMT protein expression to know whether transcriptional silencing of MGMT occurs due to promoter hypermethylation. In addition, we investigated p53 mutation status in the same tissues by PCR-SSCP analysis for comparison with the levels of MGMT protein expression. MATERIAL AND METHODS Tissue samplesA total of 26 gastric carcinoma tissue samples from 26 cases were studied. Tumor tissues and their corresponding non-neoplastic mucosae were surgically removed, frozen immediately in liquid nitrogen, and stored at Ϫ80°C until use. We confirmed microscopically that the tumor-tissue specimens consisted mainly of carcinoma tissue and that non-neoplastic mucosa did not exhibit any tumor-cell invasion or show significant inflammatory involvement. Histologic classification and tumor staging were done according to Lauren classification system 13 and the TNM Stage Grouping. 14 Cell linesEight cell lines derived from human gastric carcinoma were used. The TMK-1 cell line was established in our laboratory from poorly-differentiated adenocarcinoma. 15 Five ga...

We have previously established immortalized cells (HCF) from cementifying fibroma of the jaw bone. Here, we found that the receptor for hyaluronan (HA)-mediated motility (RHAMM) and epiregulin, a ligand for the epidermal growth factor receptor (EGFR), were highly expressed in HCF cells in comparison with osteoblasts by conducting a microarray analysis. The cell growth of HCF cells was significantly decreased by the knockdown of RHAMM using small interfering RNA (siRNA). RHAMM was associated with extracellular signal-regulated kinase (ERK) and essential for ERK phosphorylation. HCF cells had characteristic growth mechanisms in which epiregulin functions in an extracellular autocrine loop. Interestingly, exogenous HA induced the phosphorylation of EGFR, which was mainly dependent on CD44. The results raise the novel idea that the EGFR may activate Raf-MEK-ERK signaling in response to the binding of HA to CD44. Moreover, RHAMM was able to associate with TPX2 in the nucleus and was required for HA-induced activation of the Aurora A kinase. The results suggest that RHAMM has a predominant role in the cell cycle in HCF. Here, we report the new machinery by which RHAMM/ERK interaction induces the proliferative activity of cementifying fibroma cells via a specific signaling pathway through the CD44-EGFR axis. Benign fibro-osseous diseases in the oral and maxillofacial regions can be divided into three categories: fibrous dysplasia, osseous dysplasia, and cementifying (ossifying) fibroma.

No abstract

Our results show that GSK3β plays a major role in maintenance of stemness of CD44(high) /ALDH1(high) HNSCC cells. Additionally, they indicate a close relationship between CSC and mesenchymal characteristics in HNSCC.