Tadashi Matsuura

Large‐scale search of single nucleotide polymorphisms for hepatocellular carcinoma susceptibility genes in patients with hepatitis C

Hepatitis C virus (HCV) infection is a major risk factor for developing hepatocellular carcinoma (HCC). The host genetic factors that are involved in the development of HCC in patients with HCV infection remain to be investigated. To search for single nucleotide polymorphisms (SNPs) in HCC susceptibility genes, 393 SNPs in 171 candidate genes were examined in 188 Japanese patients with chronic HCV infection, including 77 patients with HCC. HCC‐related SNPs were then examined in another 188 patients (including 93 patients with HCC) with chronic HCV infection. Haplotype analyses of HCC‐related genes were performed in a total of 376 patients. Of the 393 SNPs, 31 SNPs in 29 genes were significantly associated with HCC based on an initial screening (P < .05). Of these 31 SNPs, 3 SNPs of 3 genes (SCYB14, GFRA1, and CRHR2) were significantly associated with HCC in a secondary screening. Haplotype analyses of these 3 genes identified 2 haplotype blocks associated with HCC. In conclusion, these SNPs and haplotypes located in the SCBY14, CRHR2, and GFRA1 genes will be used as markers to identify a subgroup of Japanese patients with chronic HCV infection who are at high risk of developing HCC. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270‐9139/suppmat/index.html). (HEPATOLOGY 2005;42:846–853.)

Large-scale search of SNPs for type 2 DM susceptibility genes in a Japanese population☆

The etiology of type 2 diabetes (DM) is polygenic. We investigated here genes and polymorphisms that associate with DM in the Japanese population. Single-nucleotide polymorphisms (SNPs) of 398 derived from 120 candidate genes were examined for association with DM in a population-based case-control study. The study group consisted of 148 cases and 227 controls recruited from Funagata, Japan. No evident subpopulation structure was detected for the tested population. The association tests were conducted with standard allele positivity tables (chi(2) tests) between SNP genotype frequency and case-control status. The independent association of the SNPs from serum triglyceride levels and body mass index was examined by multiple logistic regression analysis. A value of P<0.01 was accepted as statistically significant. Six genes (met proto-oncogene, ATP-binding cassette transporter A1, fatty acid binding protein 2, LDL receptor defect C complementing, aldolase B, and sulfonylurea receptor) were shown to be associated with DM.

Intronic single‐nucleotide polymorphisms in Bcl‐2 are associated with chronic obstructive pulmonary disease severity

Background and objective:  COPD is a multifactorial disease influenced by genetic and environmental factors, and gene‐by‐environmental interactions. There is considerable variability in the degree of airflow obstruction, moreover only 10–15% of chronic smokers develop COPD. These observations indicate that additional risk factors, possibly genetic, contribute to not only the susceptibility to COPD but also the development and severity of COPD. Recent paradigms highlight the presence and causal role of apoptosis in emphysema. There is a large amount of information on the genes involved in the regulation of apoptosis and one of the most studied is Bcl‐2. The aim of this study was to investigate the genetic association of Bcl‐2 gene with the level of lung function, that is, the severity, of COPD.

Identification and Characterization of the X-Dimer of Human P-Cadherin: Implications for Homophilic Cell Adhesion

Cell adhesion mediated by cadherins depends critically on the homophilic trans-dimerization of cadherin monomers from apposing cells, generating the so-called strand-swap dimer (ss-dimer). Recent evidence indicates that the ss-dimer is preceded by an intermediate species known as the X-dimer. Until now, the stabilized form of the X-dimer had only been observed in E-cadherin among the classical type I cadherins. Herein, we report the isolation and characterization of the analogous X-dimer of human P-cadherin. Small-angle X-ray scattering (SAXS) and site-directed mutagenesis data indicates that the overall architecture of the X-dimer of human P-cadherin is similar to that of E-cadherin. The X-dimerization is triggered by Ca(2+) and governed by specific protein-protein interactions. The attachment of three molecules of Ca(2+) with high affinity (Kd = 9 μM) stabilizes the monomeric conformation of P-cadherin (ΔTm = 17 °C). The Ca(2+)-stabilized monomer subsequently dimerizes in the X-configuration by establishing protein-protein interactions that require the first two extracellular domains of the cadherin. The homophilic X-dimerization is very specific, as the presence of the highly homologous E-cadherin does not interfere with the self-recognition of P-cadherin. These data suggest that the X-dimer could play a key role in the specific cell-cell adhesion mediated by human P-cadherin.

Disruption of cell adhesion by an antibody targeting the cell-adhesive intermediate (X-dimer) of human P-cadherin

Human P-cadherin is a cell adhesion protein of the family of classical cadherins, the overexpression of which is correlated with poor prognosis in various types of cancer. Antibodies inhibiting cell-cell adhesion mediated by P-cadherin show clear therapeutic effect, although the mechanistic basis explaining their effectiveness is still unclear. Based on structural, physicochemical, and functional analyses, we have elucidated the molecular mechanism of disruption of cell adhesion by antibodies targeting human P-cadherin. Herein we have studied three different antibodies, TSP5, TSP7, and TSP11, each recognizing a different epitope on the surface of the cell-adhesive domain (EC1). Although all these three antibodies recognized human P-cadherin with high affinity, only TSP7 disrupted cell adhesion. Notably, we demonstrated that TSP7 abolishes cell adhesion by disabling the so-called X-dimer (a kinetic adhesive intermediate), in addition to disrupting the strand-swap dimer (the final thermodynamic state). The inhibition of the X-dimer was crucial for the overall inhibitory effect, raising the therapeutic value of a kinetic intermediary not only for preventing, but also for reversing, cell adhesion mediated by a member of the classical cadherin family. These findings should help to design more innovative and effective therapeutic solutions targeting human P-cadherin.

Abstract 2428: PPMX-2017: Antibody against CDH3 with potent efficacy against lung cancer

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Cadherin 3/P-cadherin (CDH3) is a member of cadherin family proteins involved in the cell-cell adhesion. Based on a genome-wide cDNA microarray analysis of pancreatic cancer, we found that CDH3 is overexpressed in pancreatic cancer. We also confirmed by our immunohistochemistry study that CDH3 protein was expressed highly in pancreatic, lung, colon and other types of cancer tissues but not in normal tissues. Since CDH3 is a transmembrane glycoprotein and overexpressed in cancer tissues, it is an attractive therapeutic target for various kinds of cancer. In this present study, we generated a series of monoclonal antibodies against CDH3 and evaluated their anti-tumor effect both in vitro and in vivo. PPMX2017, an antibody from the series, is an anti-human CDH3 specific mouse IgG2a antibody. The in vitro studies demonstrated that PPMX2017 elicited strong antibody dependent cellular cytotoxicity (ADCC) activity on CDH3-positive cancer cell lines (lung cancer: NCI-H358 and A431, pancreatic cancer: KLM1 and Bxpc3.). Furthermore, PPMX2017 showed a significant antitumor effect in a therapeutic xenograft model of lung cancer where NCI-H358 cell-generated tumors grew to 70∼90 mm3 before administration of this antibody. PPMX2017 suppressed tumor growth by 60∼80% compared with control IgG in a dose range of 0.3mg∼5mg/kg. These findings show that CDH3 is a potential target for cancer therapy and PPMX2017 is a candidate for the development of antibody therapeutics. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2428.