Biomedical subjects

Souichi Yanamoto

Publications and source records attributed to Souichi Yanamoto.

9 recordsLinked to original sources

PubMed2026

A subclade-associated genomic deletion encompassing vraDEH confers increased susceptibility to nisin A and bacitracin in Staphylococcus aureus CC121.

Antimicrobial peptides (AMPs) play important roles in suppressing bacterial colonization and infection, and several AMPs are used as antimicrobial agents. Conversely, bacteria possess mechanisms that confer resistance to AMPs. We previously identified clinical Staphylococcus aureus isolates lacking the vraDEH genes, which are involved in nisin and bacitracin resistance. All such isolates belonged to clonal complex (CC) 121 and exhibited increased susceptibility to nisin A and bacitracin. The absence of vraDEH was accompanied by the absence of a 35,005-bp genomic region encompassing the biofilm-associated icaRADBC genes and a histidine biosynthesis operon. In a vraDEH-positive CC121 strain, this region was flanked by two IS1181 elements, whereas in vraDEH-negative strains it was replaced by a single IS1181 element, suggesting deletion through recombination between IS elements. Analysis of publicly available genomes revealed that all strains carrying the 35-kb deletion belonged to a single phylogenetic subclade of CC121. The downstream IS1181 insertion was frequently found in CC121 strains, whereas the upstream insertion was only found in this subclade. Across the S. aureus population, IS1181 copy number and insertion sites correlated with phylogenetic relationships, suggesting that lineage-associated IS1181 insertion may contribute to the genomic deletion in S. aureus CC121.

Nisin↗

PubMed2024

Shotgun metagenomic analysis of saliva microbiome suggests Mogibacterium as a factor associated with chronic bacterial osteomyelitis.

Osteomyelitis of the jaw is a severe inflammatory disorder that affects bones, and it is categorized into two main types: chronic bacterial and nonbacterial osteomyelitis. Although previous studies have investigated the association between these diseases and the oral microbiome, the specific taxa associated with each disease remain unknown. In this study, we conducted shotgun metagenome sequencing (≥10 Gb from ≥66,395,670 reads per sample) of bulk DNA extracted from saliva obtained from patients with chronic bacterial osteomyelitis (N = 5) and chronic nonbacterial osteomyelitis (N = 10). We then compared the taxonomic composition of the metagenome in terms of both taxonomic and sequence abundances with that of healthy controls (N = 5). Taxonomic profiling revealed a statistically significant increase in both the taxonomic and sequence abundance of Mogibacterium in cases of chronic bacterial osteomyelitis; however, such enrichment was not observed in chronic nonbacterial osteomyelitis. We also compared a previously reported core saliva microbiome (59 genera) with our data and found that out of the 74 genera detected in this study, 47 (including Mogibacterium) were not included in the previous meta-analysis. Additionally, we analyzed a core-genome tree of Mogibacterium from chronic bacterial osteomyelitis and healthy control samples along with a reference complete genome and found that Mogibacterium from both groups was indistinguishable at the core-genome and pan-genome levels. Although limited by the small sample size, our study provides novel evidence of a significant increase in Mogibacterium abundance in the chronic bacterial osteomyelitis group. Moreover, our study presents a comparative analysis of the taxonomic and sequence abundances of all genera detected using deep salivary shotgun metagenome data. The distinct enrichment of Mogibacterium suggests its potential as a marker to distinguish between patients with chronic nonbacterial osteomyelitis and chronic bacterial osteomyelitis, particularly at the early stages when differences are unclear.

Humans↗

PubMed2007

Clinicopathologic significance of EpCAM expression in squamous cell carcinoma of the tongue and its possibility as a potential target for tongue cancer gene therapy.

Epithelial adhesion molecule (EpCAM) is a transmembrane glycoprotein involved in intercellular adhesion. In particular, EpCAM appears to be overexpressed by the majority of human epithelial carcinomas, including colorectal, breast, head and neck, and hepatic carcinomas. We therefore hypothesized that EpCAM would be a good molecular target for cancer gene therapy. EpCAM protein expression in 48 primary tongue cancers and 10 normal oral mucosa was evaluated using anti-EpCAM immunohistochemistry, and correlation was examined with the clinicopathologic factors. In four human tongue cancer cell lines (SAS, HSC-2, OSC19 and OSC20), we investigated EpCAM expression by reverse transcription-polymerase chain reaction (RT-PCR). The invasive potential of cancer cells was evaluated using Matrigel invasion assay. Moreover, the effect of EpCAM inhibition was analyzed using RNA interference (RNAi). EpCAM overexpression was detected in 30 of 48 tongue cancers (62.5%), and was significantly higher in primary squamous cell carcinoma (SCC) of the tongue than in normal oral mucosa. The expression of EpCAM was significantly associated with tumor size, regional lymph node metastasis, histological differentiation and invasion pattern. Cancer cell lines with higher EpCAM expression had more invasive potential. Moreover, RNAi-mediated EpCAM reduction decreased the invasion potential and proliferation activity. These results indicated that the overexpression of EpCAM was correlated with a more aggressive phenotype of tongue cancer. Moreover, we suggested that EpCAM could be a molecular target, and that RNAi targeting EpCAM could be useful for tongue cancer gene therapy.

Aged↗

PubMed2006

Orotate phosphoribosyl transferase mRNA expression in oral squamous cell carcinoma and its relationship with the dihydropyrimidine dehydrogenase expression and the clinical effect of 5-fluorouracil.

In this study, we investigated whether orotate phosphoribosyl transferase (OPRT) correlates with the clinicopathological features and effect of 5-fluorouracil (5-FU) in human oral carcinoma. We examined the expression of OPRT mRNA by in situ hybridization in surgical specimens of oral squamous cell carcinoma. The expression of OPRT mRNA in oral carcinoma was observed in all specimens and such expression was higher than that seen in normal control tissue specimens. There was no correlation between the expression of OPRT mRNA and clinical factors, but the expression of OPRT mRNA was significantly associated with histological differentiation. The expression of OPRT mRNA showed correlation with effect of 5-FU for oral carcinoma in either in vivo or in vitro. These results suggest that the OPRT expressions may therefore be a prognostic factor of 5-FU efficacy in patients with oral squamous cell carcinoma.

Adult↗

PubMed2005

Ameloblastoma.

Explore the source record for details and available documents.

Aged↗

PubMed2004

Silencing of the p53R2 gene by RNA interference inhibits growth and enhances 5-fluorouracil sensitivity of oral cancer cells.

The p53R2 gene encodes the ribonucleotide reductase (RR) small subunit 2 homologue, and is induced by several stress signals activating p53, such as DNA-damaging agents. The p53R2 gene product causes an increase in the deoxynucleotide triphosphate (dNTP) pool in the nucleus, which facilitates DNA repair and synthesis. We hypothesized that p53R2 would be a good molecular target for cancer gene therapy. In this study, three human oral cancer cell lines (SAS, HSC-4 and Ca9-22), a human breast cancer cell line MCF-7, and a normal human fibroblast cell line NHDF were tested. We silenced the expression of p53R2 with the highly specific post-transcriptional suppression of RNA interference (RNAi). We investigated p53R2 expression with the reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The sensitivity to anticancer agents was evaluated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression of p53R2 showed no association with the mutational status of p53. The cancer cell lines with higher p53R2 expression were more resistant to 5-FU. RNAi-mediated p53R2 reduction selectivity inhibited growth and enhanced chemosensitivity in cancer cell lines but not in normal fibroblasts. These results suggest that basal transcription of p53R2 could be associated with the sensitivity to anticancer agents. Moreover, we assessed the possibility that p53R2 would be a good molecular target, and report that RNAi targeting of p53R2 could be useful for oral cancer gene therapy.

Cell Line, Tumor↗

PubMed2003

Expression of p53R2, newly p53 target in oral normal epithelium, epithelial dysplasia and squamous cell carcinoma.

Recently, the p53R2 gene has been isolated and shown to play a crucial role in DNA repair after DNA damage. The p53R2 gene encodes the p53 inducible ribonucleotide reductase small subunit 2 homologue, which is part of the p53 pathway. However, the function of p53R2 in human cancer is still unclear. We investigated p53R2 mRNA expression in human oral normal epithelium, epithelial dysplasias and squamous cell carcinomas (SCCs). Surgical or biopsy-proven specimens of 10 normal epithelium, 48 epithelial dysplasias and 63 SCCs were collected in our department. Then, p53R2 was identified by in situ hybridization to visualize and localize the expression of specific mRNAs. The authors examined the p53 gene mutation by polymerase chain reaction-single strand conformation polymorphism analysis. p53, mdm2, p21(WAF1/CIP1) and Ki-67 expression was detected by immunohistochemistry. p53R2 expression was detected in none of ten normal epithelium (0%), ten of 48 dysplasias (20.8%) and 33 of 63 SCCs (52.4%). In oral SCC, the expression of p53R2 was significantly associated with tumor size, lymph node metastasis and histological differentiation (P=0.014, 0.046 and 0.022, respectively). p53R2 expression was significantly associated with p53 abnormality in epithelial dysplasia and SCC (P=0.034 and 0.009, respectively). Of 63 patients, 37 received preoperative radiochemotherapy. p53R2 mRNA expression was significantly associated with the pathologic response to radiochemotherapy (P=0.031). This study suggested that p53R2 expression could be associated with oral carcinogenesis. The presence of p53R2 mRNA expression would be a predictive factor for tumor development, tumor cell differentiation and the sensitivity to radiochemotherapy in oral SCC.

Cell Cycle Proteins↗

PubMed2002

Thymidylate synthase and dihydropyrimidine dehydrogenase expression in oral squamous cell carcinoma: an immunohistochemical and clinicopathologic study.

OBJECTIVE: Thymidylate synthase (TS) is the target enzyme for 5-fluorouracil (5-FU), and dihydropyrimidine dehydrogenase (DPD) is the first enzyme that metabolizes 5-fluorouracil. Until now, only the enzyme activities of TS and DPD have been investigated; however, there are few reports about the immunohistochemistry of TS and DPD and none regarding oral carcinoma. The purpose of this article was to investigate the expression of TS and DPD in oral squamous cell carcinoma. STUDY DESIGN: In this study, 109 oral squamous cell carcinomas were investigated for the immunohistochemical expression of TS and DPD proteins. RESULTS: The expressions of TS in carcinoma cases was significantly higher than in controls (P <.05, t test). DPD was expressed both in carcinomas and in areas adjacent to the carcinomas. There was no correlation between the clinical factors and the TS labeling index or between the clinical factors and the DPD labeling index (DPD-LI). Pathologically, DPD-LI was significantly different in both the World Health Organization classification and Anneroth's classification. The TS labeling index was significantly correlated with the Ki-67 LI (P <.05, Pearson's correlation coefficient). Although TS showed no correlation between tegafur-uracil response and TS labeling index, there was a significant correlation between the tegafur-uracil response and DPD-LI. CONCLUSIONS: TS may reveal tumor cell proliferation, but DPD-LI may correlate with a response to anticancer drug treatment.

Adult↗

PubMed2002

p53, mdm2, and p21 expression in oral squamous cell carcinomas: relationship with clinicopathologic factors.

OBJECTIVE: The purpose of this study was to clarify the correlation of expression of cell cycle-associated gene proteins with clinicopathologic factors in oral squamous cell carcinoma (SCC). STUDY DESIGN: Formalin-fixed paraffin-embedded tissues from 69 oral SCC cases and 10 normal mucosa cases were stained by immunohistochemistry (IHC) for p53, mdm 2, and p21 proteins. RESULTS: We found p53, mdm 2, and p21 expression in 44 of 69 (63.8%), 25 of 69 (36.2%), and 37 of 69 (53.6%) oral SCCs, respectively. Ki-67-labeling index of combined p53(+)/mdm 2(+) expression cases was significantly higher than those that lacked combined expression (P =.004). Combined p53(+)/p21(+) expression showed a significant association with lymph node metastasis (P =.019). In survival analysis, combined p53(+)/p21(+) and p53(+)/mdm 2(+)/p21(+) expression was associated with poor clinical outcome (P =.018 and.012, respectively). CONCLUSION: Combined p53/mdm 2 expression was associated with tumor proliferation in oral SCC. Combined p53/p21 and p53/mdm 2/p21 expression may be a predictive factor in lymph node metastasis.

Aged↗