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BACKGROUND: This study aimed to clarify the significance of the crosstalk between hypoxia-inducible factor-1α (HIF-1α) and the Wnt/β-catenin pathway in oesophageal squamous cell carcinoma (ESCC). METHODS: The oncogenic role of HIF-1α in ESCC was investigated using in vitro and in vivo assays. The clinicopathological significance of HIF-1α, β-catenin and TCF4/TCF7L2 in ESCC were evaluated using quantitative real-time PCR and immunohistochemistry. RESULTS: The expression level of HIF-1α, β-catenin, and TCF4/TCF7L2 in T.Tn and TE1 cell lines were elevated under hypoxia in vitro. HIF-1α knockdown suppressed proliferation, migration/invasion and epithelial–mesenchymal transition (EMT) progression, induced G0/G1 cell cycle arrest, promoted apoptosis and inhibited 5-fluorouracil chemoresistance in vitro. In vivo assays showed that HIF-1α is essential in maintaining tumour growth, angiogenesis, and 5-fluorouracil chemoresistance. Mechanically, we identified the complex between HIF-1α and β-catenin, HIF-1α can directly bind to the promoter region of TCF4/TCF7L2. The mRNA level of HIF-1α, β-catenin and TCF4/TCF7L2 were increased in ESCC tumour tissues compared to the corresponding non-tumour tissues. High levels of HIF-1α and TCF4/TCF7L2 expression were correlated with aggressive phenotypes and poor prognosis in ESCC patients. CONCLUSIONS: HIF-1α serves as an oncogenic transcriptional factor in ESCC, probably by directly targeting TCF4/TCF7L2 and activating the Wnt/β-catenin pathway.

Recent progress of large-scale international studies has provided comprehensive catalogs of somatic mutations in cancers. Additionally, it has become evident that allelic imbalance in the abundance of somatic mutations between DNA and RNA were pervasive in various types of cancer. However, the allelic imbalance of the abundance of somatic mutations in esophageal squamous cell carcinoma (ESCC) has not been fully analyzed.We performed exome sequencing for 25 Japanese patients with ESCC to detect a comprehensive catalog of somatic mutations in ESCC. Additionally, we performed mRNA sequencing to evaluate the allelic imbalance of the identified somatic mutations at the transcriptional level by comparing the mutant allele frequencies between RNA and DNA.The exome sequencing showed that TP53 and ZNF750 were significantly mutated genes. The expression levels of TP53 and ZNF750 were different depending on the mutation status. In almost all the tumors with missense mutations in TP53 and ZNF750, the mutant allele frequencies were higher in the RNA sequencing than those in the exome sequencing, indicating that the mutant alleles were preferentially expressed. By examining the allelic imbalances for all the identified missense mutations, we demonstrated that genes showing preferential expressions of the mutant alleles were involved in the pathways including cell cycle, cell death, and chromatin modification.The results of this study suggest that the allelic imbalance of the abundance of somatic mutations plays important roles in the initiation and progression of ESCC by modulating cancer-related biological pathways.

Introduction: Antidiabetic drug metformin exerts various antitumor effects on different cancers. Esophageal squamous cell carcinoma (ESCC) is an intractable digestive organ cancer and new treatment strategy is required. In this study, we performed a comprehensive gene expression analysis of ESCC cell lines treated with metformin, which provided helpful information on the antitumor effects of metformin in ESCC. Next, we selected a promising gene among them and examined its effects on ESCC properties. Methods: We examined metformin-induced mRNA expression changes in two human ESCC cell lines by performing next-generation sequencing (NGS) and pathway analysis. Heat shock protein family A (Hsp70) member 6 (HSPA6) expression in surgical specimens obtained from 83 ESCC patients who underwent curative operations was evaluated immunohistochemically and analyzed. Results: Metformin upregulated mRNA expression of the many genes, including HSPA6, a cancer immune-related gene, and inhibited mRNA expression of the other many genes. Pathway analysis indicated major canonical pathways and upstream regulators related to metformin. The result indicated HSPA6 as a promising biomarker. HSPA6 expression correlated with disease-free survival (DFS) of the patients with all stage ESCC (p = 0.021), especially with stage I/II ESCC (p < 0.001). With stage III, low HSPA6 expression was not associated with poor DFS (p = 0.918). Multivariate analysis indicated that independent low HSPA6 expression was an independent poor prognostic factor of stage I/II ESCC (p < 0.001). However, HSPA6 expression did not correlate with the clinicopathological characteristics, including age, sex, tumor depth, lymph node metastasis, tumor stage, and tumor markers of the patients with stage I/II ESCC. Conclusions: This NGS analysis detected prospective candidate genes, including HSPA6. Our results indicate that HSPA6 is a promising biomarker of the recurrence risk of stage I/II ESCC. Further studies on HSPA6 would lead to better treatment.

Esophageal squamous cell carcinoma (ESCC) is a malignant cancer with a poor prognosis. Chemoradiotherapy is one of the most important strategies for patients with locally advanced unresectable ESCC; however, its therapeutic effect is unsatisfactory. Tumor-initiating cells (TICs) have been reported to be resistant to conventional chemotherapy and radiotherapy so far. Therefore, we aimed to develop a treatment strategy targeting TICs in ESCC to improve radiosensitivity.First, we validated aldehyde dehydrogenase 1 (ALDH1) as a TIC marker and investigated its ability to mediate resistance in human ESCC cell lines using flow cytometry, Western blotting, and functional analyses. Then, we focused on disulfiram (DSF), an aldehyde dehydrogenase inhibitor, used to treat alcohol use disorder. We investigated the effect of DSF and copper (II) D-gluconate (Cu) on the radiosensitivity of ESCC in xenograft mouse models.ALDH1-positive cells showed an upregulation of SOX2 and Nanog, exhibiting much stronger tumor-initiating properties than ALDH1-negative cells. Furthermore, inhibition of ALDH1 attenuated the tumor-initiating properties of ESCC cell lines. Our results also showed that ALDH1-positive cells were resistant to chemotherapy and radiotherapy, and the inhibition of ALDH1 led to the mitigation of therapeutic resistance. Our in vitro and in vivo studies revealed that the DSF/Cu complex could radiosensitize ALDH1-positive ESCC cells and downregulate the phosphoinositide 3-kinase/Akt pathway.ALDH1 inhibition by the DSF/Cu complex enhances the radiosensitivity of TICs in ESCC. The drug repositioning approach using disulfiram is a potential treatment option to overcome radioresistance in patients with locally advanced ESCC.

Our laboratory previously reported the usefulness as biomarkers of exosomes in the plasma of esophageal squamous cell carcinoma (ESCC) patients. However, the influence of tumor‐derived exosomes on the tumor itself and underlying mechanisms remain unclear. We here report changes in the phenotype and gene expression when cancer cells exist in an environment with tumor‐derived exosomes. The exosomes were isolated from the culture medium of human ESCC cells (TE2, T.Tn) by ultracentrifugation; cell proliferation assay, wound‐healing assay, and fluorescence imaging of the cell cycle were performed to clarify the phenotypic changes in the high concentration of tumor‐derived exosomes. Gene expression changes were also assessed by mRNA microarray, and the data were analyzed by gene set enrichment analysis (GSEA). The data revealed that the proliferation of both TE2 and T.Tn was inhibited, and cell migration ability was upregulated in the exosome exposure group (P, The wound closure rate was compared between groups with or without cancer‐derived exosome exposure. There was a significant difference between 10 μg/mL exosome concentration and control at 12 and 24 h in both TE2 and T.Tn (P

Aim Esophageal squamous cell carcinoma (ESCC) is a refractory digestive organ cancer that requires better treatment strategies. We have recently reported that the antidiabetic drug metformin exerts antitumor effects on ESCC by inhibition of nuclear factor kappa B (NF‐κB) nuclear translocation. In the present study, we focused on caspase recruitment domain family member 9 (CARD9), an essential signal adapter in NF‐κB activation to examine whether it can be used as a prognostic factor in ESCC. Methods We investigated CARD9 expression immunohistochemically in clinical samples obtained from 93 patients with ESCC who underwent curative esophagectomy. CARD9 expression was analyzed for correlation with clinicopathological characteristics and ESCC prognosis. The molecular effects were investigated by knocking down ESCC cells. Comprehensive RNA expression changes in these ESCC cells were detected by next‐generation sequencing (NGS). Results High CARD9 expression is significantly correlated with advanced tumor depth (P, In this report, we focused on the CARD 9 gene, which acts as an essential signal adapter in the mechanism of activating NF‐κB. We investigated CARD9 expression immunohistochemically in 93 patients with ESCC who underwent curative esophagectomy. High expression of CARD9 was significantly associated with a poor prognosis, and CARD9 expression may be a prospective prognostic biomarker in ESCC.

Background/Aim: Several articles have assessed the prognostic significance of the expression of sirtuin 1 (SIRT1) in esophageal squamous cell carcinoma (ESCC). However, evidence in this field is insufficient. Thus, we conducted a meta-analysis to investigate the prognostic and clinical impact of SIRT1 expression in ESCC. Materials and Methods: We searched the PubMed, Cochrane Library, and Web of Science databases for articles on the expression of SIRT1 and clinicopathological features in patients with ESCC. A meta-analysis was conducted. Results: Four studies with 429 patients were included. The meta-analysis revealed a significant relationship between the high expression of SIRT1 and higher T-stage (odds ratio=2.39. 95% confidence interval=1.12-5.13, p=0.02), more advanced TNM stage (odds ratio=2.35. 95% confidence interval=1.20-4.60, p=0.01), and a poor overall survival (hazard ratio=1.90, 95% confidence interval=1.45-2.47, p

Background/aim Gastric cancer (GC) with peritoneal metastasis remains difficult to treat. The anti-diabetic drug metformin exerts various antitumor effects via the 5'-adenosine monophosphate-activated protein kinase (AMPK) pathway and nuclear factor-kappa B (NF-ĸB). Therefore, we evaluated the antitumor effects of metformin for GC in vitro and on peritoneal metastasis. Materials and methods The human GC cell lines MKN1, MKN45, KATO-III and SNU-1 were used. The antiproliferative effect was evaluated in vitro with 0.5 mM or 25 mM glucose and in vivo using tumor xenograft peritoneal models of metastasis. The protein expression of AMPK, liver kinase B1 (LKB1) and NF-ĸB in tumors was examined by western blotting. Results Metformin inhibited cell proliferation in all GC lines and sensitivity was increased under low-glucose conditions in vitro. Metformin also suppressed peritoneal metastasis. In tumors, metformin reduced the numbers of proliferating cells and NF-ĸB expression, but a similar trend was not noted for AMPK. Conclusion Metformin may be a useful drug for the treatment of GC with peritoneal metastasis.

We determined the serum concentrations of Programmed cell death-1 (PD-1) and its ligands (PD-L1 and PD-L2) in patients with esophageal squamous cell carcinoma (ESCC). Blood samples were collected from 85 patients with histologically proved ESCC. Serum levels of PD-1, PD-L1, and PD-L2 were measured using enzyme linked immunosorbent assays. Correlations between serum PD-1, PD-L1, and PD-L2 concentration and tumor depth, number of lymph node metastases, organ metastasis status, or disease stage were assessed and five-year survival rates according to clinicopathological characteristics were calculated. The concentration of PD-1 was not differed according to tumor progression. On the other hand, the average concentration of PD-L1 in patients with T3/T4 disease was 15.6 (12.2–18.3) pg/mL (25–75%), and this was significantly higher than that in patients with Tis/T1/T2 disease (p = 0.020). Similarly, PD-L1 levels were significantly higher in patients with positive lymph nodes than in cases with negative lymph node involvement (p = 0.006) and were higher in patients with organ metastasis (p = 0.123) and in more advanced stage (p = 0.006). Similar tendency was observed regarding PD-L2 concentrations. PD-L2 concentration was higher in T3, T4 cases (p = 0.008), in LN positive cases (p = 0.032), and in more advanced stage (p = 0.024). Our data showed that a concentration of PD-L1 in peripheral blood was high in advanced cancer and high concentration of PD-L1 predicted disease progression and also poor survival in patients with ESCC.

Esophageal squamous cell carcinoma (ESCC) is an intractable digestive organ cancer that has proven difficult to treat despite multidisciplinary therapy, and a new treatment strategy is demanded. Metformin is used for type 2 diabetes mellitus and its antitumor effects have been reported recently. Metformin exerts antitumor effects in various respects, such as inhibiting inflammation, tumor growth and epithelial-mesenchymal transition (EMT). However, few reports have described the efficacy of metformin on ESCC, and their findings have been controversial. We analyzed the antitumor effects of metformin and clarified its effects on anti-inflammation, growth suppression and EMT inhibition. Activation of nuclear factor kappa B (NF-κB), the major transcription factor induced by inflammation, was investigated by immunostaining. We found that localization of NF-κB in the nucleus was reduced after metformin treatment. This suggests that metformin inhibited the activation of NF-κB. Metformin inhibited tumor growth and induced apoptosis in ESCC cell lines. Associated with EMT, we examined cell motility by a wound healing assay and the epithelial marker E-cadherin expression of various ESCC cell lines by western blotting. Metformin inhibited cell motility and induced E-cadherin expression. In conclusion, metformin showed multiple antitumor effects such as growth suppression, invasion inhibition, and control of EMT by inhibiting NF-κB localization on ESCC. Further exploration of the marker of treatment efficacy and combination therapy could result in the possibility for novel treatment to use metformin on ESCC.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by notorious resistance to current therapies attributed to inherent tumor heterogeneity and highly desmoplastic and immunosuppressive tumor microenvironment (TME). Unique proline isomerase Pin1 regulates multiple cancer pathways, but its role in the TME and cancer immunotherapy is unknown. Here, we find that Pin1 is overexpressed both in cancer cells and cancer-associated fibroblasts (CAFs) and correlates with poor survival in PDAC patients. Targeting Pin1 using clinically available drugs induces complete elimination or sustained remissions of aggressive PDAC by synergizing with anti-PD-1 and gemcitabine in diverse model systems. Mechanistically, Pin1 drives the desmoplastic and immunosuppressive TME by acting on CAFs and induces lysosomal degradation of the PD-1 ligand PD-L1 and the gemcitabine transporter ENT1 in cancer cells, besides activating multiple cancer pathways. Thus, Pin1 inhibition simultaneously blocks multiple cancer pathways, disrupts the desmoplastic and immunosuppressive TME, and upregulates PD-L1 and ENT1, rendering PDAC eradicable by immunochemotherapy.

Objective: ZNF750, an epidermal differentiation regulator, has been suggested to act as a tumor suppressor of esophageal squamous cell carcinoma (ESCC). Although a correlation between the epidermal differentiation gene and resistance to chemoradiotherapy (CRT) has been posited, no data regarding the ZNF750 status in ESCC have been reported. The aim of the present study was to evaluate the relationship between ZNF750 expression and response to CRT in ESCC. Methods: Eighty-seven patients who had been pathologically diagnosed with ESCC were evaluated in the present study. All patients underwent neoadjuvant CRT, followed by curative esophagectomy. The expression of ZNF750 in pretreatment biopsy samples was immunohistochemically investigated and compared to the histopathological effectiveness of CRT in surgical specimens. Results: High expression of ZNF750 was closely correlated with good sensitivity to CRT (p = 0.016). A univariate analysis showed that high/intermediate expression of ZNF750 was a significant predictive factor for good sensitivity to CRT (p = 0.006). High/intermediate expression of ZNF750 (30% or more) remained an independent predictive factor for sensitivity to CRT in a multivariate analysis (p = 0.033). Conclusions: ZNF750 expression predicts sensitivity to CRT and can be a biomarker that reliably predicts the response of ESCC to CRT.

Recently, the interest in cancer genomic medicine has increased, owing to the powerful and cost-effective technology of next-generation sequencing(NGS), which allows rapid identification of a large number of gene mutations. TP53 mutations are frequently found in solid cancers, especially in esophageal squamous cell carcinoma(ESCC), wherein the frequency of TP53 mutation is considered to be 90% or more. However, there is no clinical targeted therapy as yet utilizing TP53. Here, we aimed to characterize TP53 mutations associated with ESCC, in order to assess its feasibility as a therapeutic target. We extracted DNA and RNA from specimens of ESCC patients and analyzed them using NGS, which revealed different TP53 mutations. Based on previous reports, it is considered that different TP53 mutations lead to different functions of the protein, and subsequently account for varied prognosis in squamous cell carcinoma of the head and neck. We also performed cell viability assay using ESCC cell lines with different TP53 mutations and 2 kinds of p53-targeted drug and found differences in the growth inhibition of the cell lines. Although individual treatment can be determined depending on the type of TP53 mutation, it would be necessary to further examine the interaction of TP53 with other genes to determine its therapeutic efficacy as a target.

Immunocheckpoint inhibitors including anti-PD-1 antibody have shown certain therapeutic effects on various cancer types. They have also attracted great attention as novel cancer treatment options in addition to surgical resection, chemotherapy, and radiation therapy. Herein, we report a case of gastric cancer that was successfully treated with conversion surgery after nivolumab treatment. The patient was 68 years old and male. Upper gastrointestinal endoscopy revealed a type 3 tumor in the antrum, and he was referred to our department for further examination. The gastric cancer was diagnosed as cT4aN2M0, cStage ⅢA, and he was administered SOX as the first-line and nab-PTX/RAM as the second-line treatment, which was also a PD. As the third-line treatment, nivolumab showed remarkable reduction of the tumor after initiation, and after 14 courses, conversion surgery was performed. The patient remains alive without recurrence.

Genome medicine has been attractingmuch of attention in Japan. The combination of molecular targetingdrug s and somatic mutations has been developed for cancer treatment, which was introduced clinically with evidence by cancer type. Several cancer somatic mutations can be identified in a single test inexpensively using next-generation sequencing(NGS). Drug approval not based on organs but on cancer genome analysis has been practiced mainly in the United States, and is also being implemented in Japan. However, cancer treatment strategies using molecular targeting drugs and the associated diagnosis are limited in each type of cancer. Furthermore, the benefit of NGS, which is an improved and inexpensive technique, is still insignificant in Japan. However, the clinical biobank system was initiated in 2011 to prepare the era of cancer genome medicine in our department. The quality of biological samples was strictly controlled by the standardized sampling procedures, which can be used by the researchers accordingto their convenience. Furthermore, the cooperative research involvingcommercial corporations has been started.

Expression of genes is controlled by histone modification, histone acetylation and methylation, but abnormalities of these modifications have been observed in carcinogenesis and cancer development. The effect of the lysine-specific histone demethylase 1 (LSD1) inhibitor, a demethylating enzyme of histones, is thought to be caused by controlling the expression of genes. The aim of the present study is to elucidate the efficacies of the LSD1 inhibitor on the gene expression of esophageal cancer cell lines using chromatin immunoprecipitation (ChIP)-Seq. A comprehensive analysis of gene expression changes in esophageal squamous cell carcinoma (ESCC) cell lines induced by the LSD1 inhibitor NCL1 was clarified via analysis using microarray. In addition, ChIP-seq analysis was conducted using a SimpleChIP plus Enzymatic Chromatin IP kit. NCL1 strongly suppressed the proliferation of T.Tn and TE2 cells, which are ESCC cell lines, and further induced apoptosis. According to the combinatory analysis of ChIP-seq and microarray, 17 genes were upregulated, and 16 genes were downregulated in both cell lines. The comprehensive gene expression study performed in the present study is considered to be useful for analyzing the mechanism of the antitumor effect of the LSD1 inhibitor in patients with ESCC.

Gastric cancer (GC) with peritoneal metastasis remains difficult to treat. The anti-diabetic drug metformin exerts various antitumor effects via the 5'-adenosine monophosphate-activated protein kinase (AMPK) pathway and nuclear factor-kappa B (NF-ĸB). Therefore, we evaluated the antitumor effects of metformin for GC in vitro and on peritoneal metastasis.The human GC cell lines MKN1, MKN45, KATO-III and SNU-1 were used. The antiproliferative effect was evaluated in vitro with 0.5 mM or 25 mM glucose and in vivo using tumor xenograft peritoneal models of metastasis. The protein expression of AMPK, liver kinase B1 (LKB1) and NF-ĸB in tumors was examined by western blotting.Metformin inhibited cell proliferation in all GC lines and sensitivity was increased under low-glucose conditions in vitro. Metformin also suppressed peritoneal metastasis. In tumors, metformin reduced the numbers of proliferating cells and NF-ĸB expression, but a similar trend was not noted for AMPK.Metformin may be a useful drug for the treatment of GC with peritoneal metastasis.

Objective: ZNF750, a transcriptional regulator of epidermal differentiation, has been identified as a tumor suppressor in esophageal squamous cell carcinoma (ESCC). The aim of the present study was to investigate the clinical and prognostic significance of ZNF750 expression and to evaluate the effect of ZNF750 knockdown on cell proliferation, migration, and invasion in ESCC. Methods: A total of 124 patients with ESCC who underwent curative esophagectomy were evaluated in this study. The expression of ZNF750 in surgical specimens was immunohistochemically assessed and used in the analysis of clinicopathological features and overall survival (OS). The molecular role of ZNF750 was investigated by ZNF750 knockdown using small interfering RNA (siRNA) in ESCC cell lines. Results: Low ZNF750 expression had a significant correlation with positive lymph node metastasis (p = 0.028). Furthermore, there was a significant relationship between low expression of ZNF750 in ESCC and a poor OS, and a multivariate analysis showed that low ZNF750 expression was an independent prognostic factor (p = 0.020). The cell growth, migration, and invasion were significantly increased by downregulation of ZNF750. Conclusions: The low expression of ZNF750 was significantly associated with a poor prognosis, and ZNF750 expression may, therefore, be a reliable prognostic biomarker in ESCC.

The expression of genes can be influenced by the balance of histone acetylation and/or histone demethylation, with an imbalance of these processes possibly observed in many cancers. The histone demethylase LSD1 inhibitor activity is associated with selective transcriptional regulation and alterations in the gene expression. However, the exact mechanisms underlying the antitumor effects of LSD1 inhibitors are not fully understood. The antitumor effects of NCL1, an LSD1 inhibitor, in esophageal squamous cell cancer (ESCC) cell lines were evaluated. A comprehensive analysis of the changes in the gene expression in ESCC cell lines induced by NCL1 was carried out using a microarray analysis. A loss-of-function assay using a siRNA analysis was performed to examine the oncogenic function of the gene. NCL1 strongly inhibited the cell growth of T.Tn and TE2 ESCC cells and induced apoptosis. According to the microarray analysis, 81 genes in the T.Tn cells and 149 genes in the TE2 cells were up- or down-regulated 2-fold or more by NCL1 exposure. Among these genes, 27 were contained in both cell lines and exhibited similar expression patterns. PHLDB2, one of the genes down-regulated by NCL1, was overexpressed in the ESCC tumor tissues. Moreover, a high expression level of PHLDB2 was found to be significantly correlated with poor prognosis. The present observations of the comprehensive analysis of the gene expression levels provide insight into the mechanisms underlying the antitumor effects of LSD1 inhibitors in ESCC patients.

Background: FSCN1 and matrix metalloproteinase 14 (MMP14) are both invadopodia-related proteins. We herein elucidate the tumourigenicity of these proteins and identify novel therapeutic agents in esophageal squamous cell carcinoma (ESCC). Methods: FSCN1 and MMP14 were evaluated by immunohistochemistry and quantitative PCR, and microRNA (miR)-133a was also evaluated by PCR in surgical ESCC specimens. The roles of FSCN1, MMP14 and miR-133a were established in ESCC cells. Results: The expression of FSCN1 or MMP14 was an independent poor prognostic factor according to a multivariate analysis of immunohistochemistry, and their co-expression correlated with the poorest overall survival (OS) out of all the examined factors. Additionally, their mRNAs significantly correlated and both inversely correlated with miR-133a in surgical specimens. Transfection of a miR-133a mimic decreased the mRNA and protein levels of both FSCN1 and MMP14 in ESCC cells. The knockdown of FSCN1 or MMP14 and transfection of a miR-133a mimic inhibited the proliferation and invasion of ESCC cells. Patients with a lower miR-133a expression have a significantly poorer OS than those with a higher expression. Conclusion: The combined expression of FSCN1 and MMP14 is associated with a poor prognosis, and miR-133a, which regulates their mRNAs, can serve as a strong tumour suppressor of ESCC.

Background The expression of Fos-related antigen 1 (Fra-1) affects tumor progression, migration and invasion. We previously reported that a high Fra-1 expression level is associated with lymph node metastasis and a poor prognosis in patients with esophageal squamous cell carcinoma (ESCC). In this study, we identified the genes regulated by Fra-1 in ESCC. Methods We constructed Fra-1 knockdown models via the transfection of small interfering RNA (siRNA) into ESCC cell lines (TE10, TE11). The expression levels of the genes in the knockdown models were analyzed using a microarray experiment and Biobase Upstream Analysis (Cytoline Solutions, Tokyo, Japan), and candidate genes regulated by Fra-1 in the ESCC cell lines were detected. The actual connection of Fra-1 to the promoter region was identified in a ChIP-PCR experiment. The expression levels of the candidate genes regulated by Fra-1 in the primary tumors of surgical specimens obtained from ESCC patients (n = 135) were compared to those observed in normal tissues using real-time PCR and immunohistochemical staining, and the clinicopathological features were analyzed. Results The results of the Biobase Upstream Analysis and ChIP-PCR showed high mobility group protein 1 (HMGA1) and hyaluronan mediated motility receptor (HMMR) to be significant genes regulated by Fra-1. The expression levels of both HMGA1 and HMMR were found to closely correlate with the Fra-1 expression in the clinical specimens. The patients with a positive HMGA1 expression had a poorer prognosis than those with a negative expression (P = 0.017) and the patients with positive HMMR expression also had a poorer prognosis (P = 0.018). Moreover, a multivariate analysis demonstrated a positive HMGA1 expression to be a significant independent prognostic factor in the ESCC patients. Conclusion HMGA1 and HMMR are regulated by Fra-1 in the setting of ESCC and the HMGA1 expression is significantly associated with a poor prognosis in ESCC patients. Downregulating the HMGA1 and HMMR expression may become a practical treatment strategy against ESCC in the future. Disclosure All authors have declared no conflicts of interest.

In recent years, large-scale international studies have provide comprehensive catalogues of genomic alterations in cancers including Esophageal Squamous Cell Cancer(ESCC). They revealed that some gene associated with cell cycle/apoptosis pathway, NOTCH pathway, WNT pathway, such as TP53 and NOTCH1, harbored genetic abnormalities frequently. As the next step clinical sequencing studies are starting to evaluate efficacy of using targeted agents to patients with specific molecular aberrations. We performed exome sequencing and RNA sequencing for 25 Japanese patients with esophageal squamous cell carcinoma (ESCC) to provide a comprehensive catalogue of genomic abnormalities in ESCC and found TP53 and ZNF750 significantly mutated genes. Additionally, we performed allele specific expression analysis of TP53, integrating mRNA sequencing data into the information of genomic abnormality. This analysis revealed that levels of expression changes depending on mutation types and nearly mono-allelic expression of TP53 was a common signature of ESCC patients with somatic mutations. And pattern of mono-allelic expression was dependent on mutation types. We expanded this analysis to all genes with somatic SNV mutations and revealed that mutant allele specific expression was observed in other genes including ZNF750, and many of them were belonged to cancer pathway in KEGG database. About TP53, our investigation might provide better understanding of the involvement of somatic mutations. And fluctuations in transcriptional regulation of TP53 could be predicted based on type of somatic mutation. In addition to this, analysis of allele specific expression suggested that not only somatic mutation of DNA, but also mutant allele expression should be considered to understand cancer genetic pathophysiology better and build more effective therapeutic strategies. Citation Format: Masahiko Takahashi, Hirofumi Nakaoka, Yasunori Akutsu, Naoyuki Hanari, Kentaro Murakami, Masayuki Kano, Yasunori Matsumoto, Ryota Otsuka, Nobufumi Sekino, Masaya Yokoyama, Itsuro Inoue, Hisahiro Matsubara. Analysis of allele specific expression in esophageal squamous cell carcinoma with combination of exome sequencing and mRNA Sequencing [abstract]. In: Proceedings of the AACR Precision Medicine Series: Opportunities and Challenges of Exploiting Synthetic Lethality in Cancer; Jan 4-7, 2017; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2017;16(10 Suppl):Abstract nr B07.

Exosomes are small membrane vesicles (30-100 nm) released by many types of cells including cancer cells, and are thought to play an important role in cell-to-cell communications. Exosomes contain lipids, proteins, and nucleic acids such as mRNAs or microRNAs, they are tought to have relationship with tumor growth or metastasis. Our laboratory was previously reported the level of microRNA-1246, expressed mainly in tumor tissues of esophageal squamous cell carcinoma (ESCC), was significantly high in exosomes extracted from the serum of ESCC patients. However, the exosome dynamics and transportation between cancer cells and the other cells are still unclear. In this study, we assessed the cell-to-cell communication via exosomes with fluorescent imaging and analyzed the effect of cancer cell derived exosome to tumor progression. In order to image and analyze the movement of cancer cell-derived exosomes, green fluorescent protein (GFP)-tagged CD63, which is a general marker of exosomes, was expressed in human esophageal squamous cancer cell line TE2. Exosomes were extracted from supernatant with ultracentrifuge method. Extracted GFP-tagged exosomes were added to the other cells to obtain the images of transportation. The effects of exosomes to tumor progression were also assessed with cell proliferation assay, invasion oassay, and migration assay. Our data indicates that cancer cell derived exosomes affect tumor progression. Citation Format: Yasunori Matsumoto, Masayuki Kano, Yasunori Akutsu, Takanori Nishimori, Naoyuki Hanari, Isamu Hoshino, Kentaro Murakami, Takeshi Toyozumi, Hiroshi Suito, Masahiko Takahashi, Nobufumi Sekino, Yoshihiro Nabeya, Hisahiro Matsubara. Functional analysis of exosomes derived from human esophageal squamous cell carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4032. doi:10.1158/1538-7445.AM2015-4032