Yuri Tanaka

Function and diagnostic value of Anosmin-1 in gastric cancer progression.

Gastric cancer (GC) is a major global health problem that urgently requires novel molecular biomarkers for patient stratification as well as therapeutic targets. Anosmin‐1 (ANOS1) gene encodes a cell adhesion molecule that plays diverse roles in multiple malignancies. We performed global expression profiling of GC cell lines and small interfering RNA (siRNA) experiments to determine the effect of ANOS1 expression on phenotype. We evaluated the association of ANOS1 mRNA and protein levels in patients’ tissue and sera with clinicopathological factors of GC subtypes. Differential expression of ANOS1 mRNA by GC cell lines correlated positively to levels of ITGAV, FOXC2 and NODAL mRNAs and inversely with those of TFPI2. Inhibiting ANOS1 expression decreased the proliferation, invasion and migration of GC cells. The mean level of ANOS1 mRNA was significantly higher in 237 GC tissues compared with the corresponding noncancerous adjacent tissues. Elevated ANOS1 levels associated significantly with the phenotypes of GC, shorter disease‐free and overall survival. ANOS1 expression was a more significant prognostic marker for diffuse and distal nondiffuse GC. ANOS1 concentrations in sera increased sequentially in sera of healthy subjects, localized GC and disseminated GCs. Prognosis was worse for patients with preoperative serum ANOS1 ≥600 pg/ml compared with those with <600 pg/ml. ANOS1 may represent a biomarker for GC phenotypes and as a target for therapy.

Adherens junctions associated protein 1 serves as a predictor of recurrence of squamous cell carcinoma of the esophagus

Esophageal squamous cell carcinoma (ESCC), the most common esophageal cancer in East Asia, is among the six cancers with the highest fatality rates worldwide. Unfortunately, multidisciplinary treatment strategies have not achieved satisfactory outcomes. Therefore, novel insights into the molecular biology of ESCC are required to improve treatment. The gene encoding the transmembrane adherens junctions-associated protein-1 (AJAP1) expressed by epithelial cells resides in chromosome 1p36, which is frequently lost or epigenetically silenced in several malignancies. Here, we investigated the expression levels and regulatory mechanism of AJAP1 transcription. We determined the levels of AJAP1 mRNA and the genes encoding potentially interacting proteins expressed by ESCC cell lines, as well as the chromosomal copy number of AJAP1 and the methylation status of its promoter region. AJAP1 mRNA levels of 78 pairs of surgically resected specimens were determined to evaluate the association of AJAP1 expression and clinicopathological factors. Nine ESCC cell lines differentially expressed AJAP1 mRNA, and demethylation of hypermethylated AJAP1 genomic DNA reactivated AJAP1 mRNA expression. The copy number of sequences upstream or downstream of the AJAP1 transcriptional start site was not detectably altered. AJAP1 mRNA levels correlated inversely with those of ezrin (EZR) and were significantly lower in ESCC tissues compared with adjacent normal tissues. AJAP1 mRNA levels decreased gradually with increasing tumor stage. Patients with downregulated AJAP1 transcription were more likely to experience shorter overall and disease-free survival. Multivariate analysis of disease-free survival identified downregulated AJAP1 transcription as an independent prognostic factor. These results suggest that in ESCC, AJAP1 acts as a putative tumor suppressor and that AJAP1 transcription is regulated by promoter hypermethylation. These findings indicate that downregulated AJAP1 transcription may serve as a novel tumor biomarker to predict recurrence of ESCC after esophagectomy.

Reduced Expression of Adherens Junctions Associated Protein 1 Predicts Recurrence of Hepatocellular Carcinoma After Curative Hepatectomy

BackgroundHepatocellular carcinoma (HCC) frequently recurs after curative resection. Therefore, the availability of sensitive biomarkers for progression and recurrence is essential for managing patients’ clinical course. Adherens junctions associated protein 1 (AJAP1) may serve this purpose, because it mediates activities of tumor cells.MethodsAJAP1 mRNA levels and those of genes encoding potential interacting proteins, such as SRC in HCC cell lines, and 144 pairs of resected liver tissues were determined as well as the methylation status of the AJAP1 promoter and copy number changes at AJAP1 locus. The expression pattern of AJAP1 protein was evaluated using immunohistochemistry.ResultsAJAP1 mRNA levels varied among nine HCC cell lines, and AJAP1 expression was reactivated after demethylation of its promoter. AJAP1 mRNA levels correlated inversely with those of SRC in HCC cell lines and tissues. AJAP1 mRNA levels were suppressed in HCC tissues. The expression pattern of AJAP1 correlated significantly with that of AJAP1 mRNA. Low levels of AJAP1 mRNA in patients with HCC associated significantly with elevated levels of tumor markers, larger tumor size, serosal infiltration, vascular invasion, hypermethylation of the AJAP1 promoter, and copy number loss at AJAP1 locus. Patients with low levels of AJAP1 expression were more likely to experience shorter disease-free survival (DFS), and multivariate analysis identified low AJAP1 expression as an independent factor for predicting DFS.ConclusionsAJAP1 may function as a key regulatory molecule associated with the recurrence of HCC. Hypermethylation of the AJAP1 promoter is a key regulatory mechanism controlling AJAP1 expression.

Neurotrophin Receptor-Interacting Melanoma Antigen-Encoding Gene Homolog is Associated with Malignant Phenotype of Gastric Cancer

BackgroundIdentification of novel molecules implicated in the malignancy of gastric cancer (GC) is key to the development of personalized treatments and the improvement of patient outcome. Neurotrophin receptor-interacting melanoma antigen-encoding protein (NRAGE) regulates apoptosis and metastasis via interactions with various genes. This study aimed to evaluate the function and clinical significance of NRAGE in GC.MethodsThe expression of NRAGE and its putative interacting genes apoptosis antagonizing transcription factor (AATF), p75 neurotrophin receptor (p75NTR), and proliferating cell nuclear antigen (PCNA) were determined in GC cell lines using reverse transcription-polymerase chain reaction (RT-PCR). The effect of NRAGE knockdown by small interfering RNA (siRNA) on GC cell behavior also was evaluated. In addition, NRAGE expression was determined in 179 pairs of resected gastric tissues.ResultsExpression of NRAGE mRNA positively correlated with that of AATF, and NRAGE knockdown significantly decreased the proliferation, migration, and invasion of GC cells. The mean level of NRAGE mRNA expression was significantly higher in GC tissues than in corresponding adjacent normal tissues. The expression patterns of NRAGE mRNA and protein were closely correlated. A stepwise elevation in NRAGE mRNA expression in GC tissues was observed with increasing Union for International Cancer Control (UICC) stage. High NRAGE expression in GCs was associated with shortened recurrence-free survival and identified as an independent prognostic factor (hazard ratio, 1.83; 95 % CI, 1.12–3.02, p = 0.017).ConclusionsThe results indicate that NRAGE represents a putative oncogene associated with a malignant phenotype of GC. In GC, NRAGE may serve as a predictive biomarker and a target of molecular therapy.

Translational implication of Kallmann syndrome-1 gene expression in hepatocellular carcinoma.

Accumulation of epigenetic alterations causes inactivation of tumor suppressors and contributes to the initiation and progression of hepatocellular carcinoma (HCC). Identification of methylated genes is necessary to improve our understanding of the pathogenesis of HCC and develop novel biomarkers and therapeutic targets. The Kallmann syndrome-1 (KAL1) gene encodes an extracellular matrix-related protein with diverse oncological functions. However, the function of KAL1 in HCC has not been examined. We investigated the methylation status of the KAL1 promoter region in HCC cell lines, and evaluated KAL1 mRNA levels and those of genes encoding potential interacting cell adhesion factors. KAL1 mRNA expression level was heterogeneous in nine HCC cell lines, and reactivation of KAL1 mRNA expression was observed in cells with promoter hypermethylation of KAL1 gene after demethylation. In addition, KAL1 mRNA levels inversely correlated with those of ezrin in all nine HCC cell lines. KAL1 expression levels in 144 pairs of surgically-resected tissues were determined and correlated to clinicopathological parameters. KAL1 mRNA level was independent of the background liver status, whereas HCC tissues showed significantly lower KAL1 mRNA levels than corresponding noncancerous liver tissues. Downregulation of KAL1 mRNA in HCC was significantly associated with malignant phenotype characteristics, including elevated tumor markers, larger tumor size, vascular invasion, and hypermethylation of KAL1. Patients with downregulation of KAL1 were more likely to have a shorter overall survival than other patients, and multivariate analysis identified downregulation of KAL1 as an independent prognostic factor (hazard ratio 2.04, 95% confidence interval 1.11-3.90, P=0.022). Our results indicated that KAL1 may act as a putative tumor suppressor in HCC and is inactivated by promoter hypermethylation. KAL1 may serve as a biomarker of malignant phenotype of HCC.

Suppression of SAMSN1 Expression is Associated with the Malignant Phenotype of Hepatocellular Carcinoma.

BackgroundIdentification of molecular markers for sensitive detection of hepatocellular carcinoma (HCC) is required to achieve efficacious personalized therapy.MethodsWe focused here on SAM domain, SH3 domain, and nuclear localization signals 1 (SAMSN1) and investigated expression and methylation status of SAMSN1 in HCC cell lines and 144 pairs of surgical specimens.ResultsSAMSN1 was expressed at significantly lower levels in tumor tissue compared with the corresponding noncancerous tissues of patients with HCC. Analysis of HCC cell lines revealed that hypermethylation of the SAMSN1 promoter correlated with decreased expression of SAMSN1 mRNA. Furthermore, treating cells with a DNA-demethylating drug increased SAMSN1 transcription. The levels of SAMSN1 mRNA in noncancerous liver were not affected by background liver inflammation or fibrosis. Moreover, the levels of SAMSN1 mRNA in HCC tissues inversely correlated with tumor size and preoperative levels of proteins induced by vitamin K absence. The clinical significance of SAMSN1 was further indicated by the correlation between its decreased expression in patients with HCC and their shorter overall and recurrence-free survival as well as recurrence following initial resection. Moreover, multivariate analysis identified SAMSN1 as an independent prognostic factor of HCC progression. The expression pattern of SAMSN1 correlated significantly with that of SAMSN1 mRNA, making it possible to use PCR techniques to readily quantitate SAMSN1 expression in tumors.ConclusionsOur findings indicate that inhibition of SAMSN1 transcription through DNA hypermethylation may influence the progression of HCC and thus represent a novel biomarker of the phenotype of HCC cells.

Prognostic relevance of SAMSN1 expression in gastric cancer

The prognosis for patients with advanced gastric cancer (GC) remains poor. The identification of biomarkers relevant to the recurrence and metastasis of GC is advantageous for stratifying patients and proposing novel molecular targets. In the present study the oncological roles of SAM domain, SH3 domain and nuclear localization signals 1 (SAMSN1), a mediator of B-cell function, were elucidated in GC. The expression and methylation status of SAMSN1 were investigated in a panel of 11 GC cell lines. Immunohistochemical staining was performed to determine the pattern of SAMSN1 protein expression in gastric tissues. The prognostic impact of SAMSN1 expression was determined by analyzing 175 pairs of surgically resected gastric tissues. A marked decrease in the level of SAMSN1 mRNA was detected in 8/11 GC cell lines as compared with that in a non-transformed intestinal epithelium cell line (FHs 74) without promoter methylation. The mean expression level of SAMSN1 mRNA was reduced in GC tissues compared with normal adjacent tissues, an observation that was independent of tumor differentiation. The pattern of SAMSN1 protein expression was significantly correlated with that of SAMSN1 mRNA. Low SAMSN1 mRNA expression was significantly associated with tumor size (>60 mm; P=0.026) and shorter overall survival times (P=0.004). Multivariate analysis identified low SAMSN1 mRNA expression as an independent prognostic factor for poor overall survival (hazard ratio, 1.80; 95% confidence interval, 1.07-3.05; P=0.025). The difference in survival between the low and high SAMSN1 expression groups was more marked in patients with stage II/III GC compared to those with stage IV GC. In patients with stage II/III GC who underwent curative surgery, low SAMSN1 expression was associated with reduced disease free survival times. The results of the present study indicate that downregulation of SAMSN1 transcription may affect the progression and recurrence of GC, and therefore may represent a novel biomarker of GC.

Clinical utility of the platelet-lymphocyte ratio as a predictor of postoperative complications after radical gastrectomy for clinical T2-4 gastric cancer

AIM To identify simple and sensitive markers for postoperative complications after gastrectomy, the predictive values were compared among candidate preoperative factors. METHODS Three-hundred and twelve patients with previously untreated clinical T2-4 gastric cancer who underwent a D2 standard gastrectomy (distal gastrectomy or total gastrectomy) were included in the analysis. Correlations between 21 parameters that can be determined by preoperative routine blood tests and clinically relevant postoperative complications (grade II or higher according to the Clavien-Dindo classification) were evaluated. The optimal cutoff values and clinical significance of the selected markers were further evaluated by subgroup analyses according to age, body mass index, operative procedure and clinical disease stage. RESULTS Sixty-six patients (21.1%) experienced grade II or higher postoperative complications. The platelet-lymphocyte ratio (PLR, total lymphocyte count/platelet count × 100) exhibited the highest area under the curve value (0.639) for predicting postoperative complications among the 21 parameters, and the optimal cutoff value was determined to be 0.71 (sensitivity = 70%, specificity = 56%). In the univariate analysis, the odds ratio of a low PLR for the occurrence of postoperative complications was 2.94 (95%CI: 1.66-5.35, P < 0.001), and a multivariate binomial logistic analysis involving other potential risk factors identified a low PLR as an independent risk factor for postoperative complications (OR = 3.32, 95%CI: 1.82-6.25, P < 0.001). In subgroups classified according to age, body mass index, operative procedure and clinical disease stage, the low PLR group exhibited an increased incidence of postoperative complications. CONCLUSION The preoperative PLR is a simple and useful predictor of complications after curative gastrectomy in patients with clinical T2-4 gastric cancer.

Perioperative Serum Carcinoembryonic Antigen Levels Predict Recurrence and Survival of Patients with Pathological T2-4 Gastric Cancer Treated with Curative Gastrectomy

Background/Aims: Do serum carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 levels serve as prognostic indicators in patients with gastric cancer (GC)? This is a question that has long been disputed. The aim of this study was to evaluate the significance of perioperative serum levels of CEA and CA19-9 for predicting the recurrence and long-term survival after patients with pT2-4 GC undergo curative gastrectomy. Methods: This study included 251 patients with radically resected pT2-4 GC without preoperative treatment. Associations between the preoperative and postoperative serum levels of CEA or CA19-9 and postoperative long-term outcomes and recurrence patterns were evaluated. Results: Preoperative CEA >5.0 ng/mL was an independent prognostic factor of overall survival. Elevation of both preoperative CEA and CA19-9 levels showed no synergistic adverse effects on prognosis. Preoperative levels of these markers achieved superior predictive performance compared with the postoperative values. Adverse prognosis is significantly associated with persistent elevation of CEA levels before and after gastrectomy. Elevation of CEA levels, particularly at postoperative measurement, was significantly associated with hematogenous recurrence. Conclusion: Determination of perioperative CEA levels facilitated predictions of recurrence patterns and prognosis among patients with pT2-4 GC who underwent curative gastrectomy.