Naoyuki Hanari

Serum microRNA expression profile: miR-1246 as a novel diagnostic and prognostic biomarker for oesophageal squamous cell carcinoma

Background:Recent studies have demonstrated that microRNAs (miRNAs) are stably detectable in blood and can serve as useful biomarkers for cancer.Methods:We performed an miRNA array using serum samples obtained from oesophageal squamous cell carcinoma (ESCC) patients or healthy controls. MiR-1246 was the most markedly elevated in ESCC patients. Therefore, miR-1246 was selected as a candidate for further analysis. The serum miR-1246 level in 46 healthy controls and 101 ESCC patients was evaluated and compared among various clinicopathological characteristics. MiR-1246 expressions in tissue, exosomal, and cellular samples were also examined.Results:Serum miR-1246 alone yielded an receiver-operating characteristic curve area of 0.754, with 71.3% sensitivity and 73.9% specificity for distinguishing ESCC patients from healthy controls. Serum miR-1246 was significantly correlated with the TNM stage and showed to be the strongest independent risk factor for poor survival (HR, 4.032; P=0.017). Unlike the tendency shown in previous reports, miR-1246 was not upregulated in ESCC tissue samples. Furthermore, exosomal miR-1246 did not reflect the abundance in the cell of origin.Conclusion:These data support our contention that serum miR-1246 has strong potential as a novel diagnostic and prognostic biomarker in ESCC, and its releasing mechanism is selective and independent of tissue miRNA abundance.

Identification of novel molecular targets regulated by tumor suppressive miR-375 induced by histone acetylation in esophageal squamous cell carcinoma

The aim of this study was to determine whether histone acetylation regulates tumor suppressive microRNAs (miRNAs) in esophageal squamous cell carcinoma (ESCC) and to identify genes which are regulated by these miRNAs. We identified a miRNA that was highly upregulated in an ESCC cell line by cyclic hydroxamic acid-containing peptide 31 (CHAP31), one of the histone deacetylase inhibitors (HDACIs), using a miRNA array analysis. miR-375 was strongly upregulated by CHAP31 treatment in an ESCC cell line. The expression levels of the most upregulated miRNA, miR-375 were analyzed by quantitative real-time PCR in human ESCC specimens. The tumor suppressive function of miR-375 was revealed by restoration of miR-375 in ESCC cell lines. We performed a microarray analysis to identify target genes of miR-375. The mRNA and protein expression levels of these genes were verified in ESCC clinical specimens. LDHB and AEG-1/MTDH were detected as miR‑375-targeted genes. The restoration of miR-375 suppressed the expression of LDHB and AEG-1/MTDH. The ESCC clinical specimens exhibited a high level of LDHB expression at both the mRNA and protein levels. A loss-of-function assay using a siRNA analysis was performed to examine the oncogenic function of the gene. Knockdown of LDHB by RNAi showed a tumor suppressive function in the ESCC cells. The correlation between gene expression and clinicopathological features was investigated by immunohistochemistry for 94 cases of ESCC. The positive staining of LDHB correlated significantly with lymph node metastasis and tumor stage. It also had a tendency to be associated with a poor prognosis. Our results indicate that HDACIs upregulate miRNAs, at least some of which act as tumor suppressors. LDHB, which is regulated by the tumor suppressive miR-375, may therefore act as an oncogene in ESCC.

Histone Deacetylase Inhibitor FK228 Activates Tumor Suppressor Prdx1 with Apoptosis Induction in Esophageal Cancer Cells

Purpose: The histone deacetylase inhibitor FK228 shows strong activity as a potent antitumor drug but its precise mechanism is still obscure. The purpose of this study is to reveal the effect of FK228 on gene expression in the cell and to determine the mechanism of the antitumor activity of FK228 for further clinical applications. Experimental Design and Results: Microarray analysis was applied to verify the gene expression profiles of 4,608 genes after FK228 treatment using human esophageal squamous cell cancer cell lines T.Tn and TE2. Among them, peroxiredoxin 1 (Prdx1), a member of the peroxiredoxin family of antioxidant enzymes having cell growth suppression activity, as well as p21WAF1, were significantly activated by FK288. In addition, FK228 strongly inhibited the cell growth of T.Tn and TE2 by the induction of apoptosis. Further, chromatin immunoprecipitation analysis revealed that FK228 induced the accumulation of acetylated histones H3 and H4 in Prdx1 promoter, including the Sp1-binding site. In mouse xenograft models of T.Tn and TE2 cells, FK228 injection resulted in significant tumor regression as well as activated Prdx1 expression in tumor tissues. Prdx1 suppression by RNA interference hindered the antitumor effect of FK228. Conclusion: Our results indicate that the antitumor effect of FK228 in esophageal cancer cells is shown at least in part through Prdx1 activation by modulating acetylation of histones in the promoter, resulting in tumor growth inhibition with apoptosis induction.

Surgical advantages of gastric SMTs by laparoscopy and endoscopy cooperative surgery.

BACKGROUND/AIMS The treatment of gastric submucosal tumors (SMTs) is strictly surgical and enucleation of the tumor or wedge resection of the stomach is efficient to achieve R0 resection. Laparoscopic and endoscopic cooperative surgery (LECS) can be safely performed with adequate cutting lines. This study describes the initial 16 cases treated by LECS and evaluates the advantages by LECS for gastric SMTs retrospectively. METHODOLOGY Sixteen patients with gastric SMT underwent LECS from June 2007 to December 2010, their surgical data, clinical characteristics and surgical specimens of SMTs were compared. The surgical specimens of 9 gastric SMTs treated by laparoscopic wedge resection (LWR) were compared as a control. RESULTS The median (range) length of operation time, blood loss, hospital stay after surgery were minutes 172 (115- 220), <5mL (<5-115) and 10 days (6-17), respectively. The median (range) ratio of the longest diameter of the tumor divided by the longest diameter of the surgical specimen in LECS and LWR were 0.86 (0.625-1.0) and 0.69 (0.44-1.0), respectively (p=0.0189, Wilcoxon rank sum test). CONCLUSIONS LECS minimizes the surgical specimen while still providing sufficient surgical margins to successfully cure gastric SMTs.

Quantification of plasma exosome is a potential prognostic marker for esophageal squamous cell carcinoma

Exosomes play important roles in cancer progression. Although its contents (e.g., proteins and microRNAs) have been focused on in cancer research, particularly as potential diagnostic markers, the exosome behavior and methods for exosome quantification remain unclear. In the present study, we analyzed the tumor-derived exosome behavior and assessed the quantification of exosomes in patient plasma as a biomarker for esophageal squamous cell carcinoma (ESCC). A CD63-GFP expressing human ESCC cell line (TE2-CD63-GFP) was made by transfection, and mouse subcutaneous tumor models were established. Fluorescence imaging was performed on tumors and plasma exosomes harvested from mice. GFP-positive small vesicles were confirmed in the plasma obtained from TE2-CD63-GFP tumor-bearing mice. Patient plasma was collected in Chiba University Hospital (n=86). Exosomes were extracted from 100 µl of the plasma and quantified by acetylcholinesterase (AChE) activity. The relationship between exosome quantification and the patient clinical characteristics was assessed. The quantification of exosomes isolated from the patient plasma revealed that esophageal cancer patients (n=66) expressed higher exosome levels than non-malignant patients (n=20) (P=0.0002). Although there was no correlation between the tumor progression and the exosome levels, exosome number was the independent prognostic marker and low levels of exosome predicted a poor prognosis (P=0.03). In conclusion, exosome levels may be useful as an independent prognostic factor for ESCC patients.

A COX-2 inhibitor enhances the antitumor effects of chemotherapy and radiotherapy for esophageal squamous cell carcinoma

Cyclooxygenase-2 (COX-2) is a key enzyme of prostaglandin (PG) synthesis that has been demonstrated to be overexpressed in several types of cancers. The function of COX-2 in tumor progression has been recently elucidated. In tumors in which COX-2 is overexpressed, the antitumor effects are suppressed. We examined the effects of celecoxib, a COX-2 inhibitor, in enhancing the antitumor effects of chemotherapy and radiotherapy for esophageal squamous cell carcinoma (ESCC) by reducing the COX-2 activity. We used the human esophageal squamous cell lines TE2 and T.Tn treated with celecoxib and 5-FU/radiation, after which cell viability assays were performed. Changes in the expressions of dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT) mRNA and PGE2 were also measured. In addition, apoptotic changes, and the invasion and migration activity in both the celecoxib and 5-FU treated cells were evaluated. The experiments showed that T.Tn and TE2 proliferation was strongly inhibited by the combination of 5-FU/radiation and the COX-2 inhibitor. Inhibiting the COX-2 activity induced a reduction in PGE2 levels in TE2/T.Tn cells. Following treatment with the COX-2 inhibitor and 5-FU, the OPRT expression was upregulated and the DPD expression was downregulated in the resistant cells. In addition, the combination treatment with the COX-2 inhibitor and 5-FU markedly inhibited both the cell invasion and migration activity. Therefore, COX-2 inhibitors can be useful enhancers of antitumor drugs and radiotherapy for ESCC.

Modulated electro-hyperthermia enhances dendritic cell therapy through an abscopal effect in mice

The aim of this study was to assess whether modulated electro-hyperthermia (mEHT) can induce an abscopal effect and thereby enhance the antitumor effects of immunotherapy. We used an intratumoral dendritic cell (DC) injection and mEHT to treat C3H/He mice inoculated with squamous cell carcinoma SCCVII cells in the left leg, and we assessed the whole body antitumor effects. Tumors were examined every two or three days in order to assess growth inhibition. The tumor-draining lymph nodes were removed to enable flow cytometric analysis of CD3+ and CD8+ cells, whereas immunohistochemistry was used to assess CD8, S100 and Foxp3 expression in the tumors. Additionally, GP96 expression in the tumors from the different treatment groups was measured. In the control group, the mean tumor volume was larger than that in other groups. These results indicated that the combination therapy of an intratumoral DC injection and mEHT evoked systemic antitumor activity. A larger number of CD3+ and CD8+ cells were detected by flow cytometric analysis in the DC plus mEHT treatment group. Tumor tissue immunostaining showed that CD8 and S100 were more strongly expressed in the DC plus mEHT treatment group, although Foxp3 expression was much higher in the control group. The GP96 gene expression level in the mEHT group was significantly different from the expression level in the control group. An abscopal effect may be induced by mEHT, and the effect of immunotherapy with DCs was strongly enhanced by the overexpression of GP96. GP96 is thought to be one of the molecules explaining the abscopal effect. Direct intratumoral administration of DCs and mEHT may be a feasible future treatment strategy.

Utility of arterial phase of dynamic CT for detection of intestinal ischemia associated with strangulation ileus

AIM To clarify the usefulness of arterial phase scans in contrast computed tomography (CT) imaging of strangulation ileus in order to make an early diagnosis. METHODS A comparative examination was carried out with respect to the CT value of the intestinal tract wall in each scanning phase, the CT value of the content in the intestinal tract, and the CT value of ascites fluid in the portal vein phase for a group in which ischemia was observed (Group I) and a group in which ischemia was not observed (Group N) based on the pathological findings or intra-surgical findings. Moreover, a comparative examination was carried out in Group I subjects for each scanning phase with respect to average differences in the CT values of the intestinal tract wall where ischemia was suspected and in the intestinal tract wall in non-ischemic areas. RESULTS There were 15 subjects in Group I and 30 subjects in Group N. The CT value of the intestinal tract wall was 41.8 ± 11.2 Hounsfield Unit (HU) in Group I and 69.6 ± 18.4 HU in Group N in the arterial phase, with the CT value of the ischemic bowel wall being significantly lower in Group I. In the portal vein phase, the CT value of the ischemic bowel wall was 60.6 ± 14.6 HU in Group I and 80.7 ± 17.7 HU in Group N, with the CT value of the ischemic bowel wall being significantly lower in Group I; however, no significant differences were observed in the equilibrium phase. The CT value of the solution in the intestine was 18.6 ± 9.5 HU in Group I and 10.4 ± 5.1 HU in Group N, being significantly higher in Group I. No significant differences were observed in the CT value of the accumulation of ascites fluid. The average difference in the CT values between the ischemic bowel wall and the non-ischemic bowel wall for each subject in Group I was 33.7 ± 20.1 HU in the arterial phase, being significantly larger compared to the other two phases. CONCLUSION This is a retrospective study using a small number of subjects; however, it suggests that there is a possibility that CT scanning in the arterial phase is useful for the early diagnosis of strangulation ileus.

ZNF750 Expression as a Novel Candidate Biomarker of Chemoradiosensitivity in Esophageal Squamous Cell Carcinoma

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.

Usefulness of microRNA‑375 as a prognostic and therapeutic tool in esophageal squamous cell carcinoma.

The aim of this study was to clarify the importance of microRNA‑375 (miR‑375) expression in patients with esophageal squamous cell carcinoma (ESCC) and to examine the in vivo antitumor effects of miR‑375 in a model of ESCC using a non‑viral delivery system. We estimated the miR‑375 and LDHB and AEG‑1/MTDH mRNA expression of the ESCC tumors from 85 patients. The correlation between the miR‑375 expression and clinicopathological features, including the prognosis, were evaluated. The presence of high miR‑375 expression was associated with lymphatic vessel invasion, while a low expression of miR‑375 significantly correlated with a poor prognosis for the 85 ESCC patients. We also found that there was a significant inverse correlation between the expression of miR‑375 and that of LDHB. Before the examination of miR‑375 in the in vivo assay, we confirmed that atelocollagen prolonged the accumulation of miRNA by using fluorescently‑labeled miRNA and an in vivo imaging system. We injected the miR‑375/atelocollagen complex or a control‑miRNA/atelocollagen complex into mice bearing TE2 and T.Tn xenografts via subcutaneous (s.c.) injections. The growth of both the TE2 and T.Tn tumors in the miR‑375 groups was significantly suppressed compared with that in the control‑miRNA groups. In addition, The LDHB mRNA expression of TE2 xenografts was significantly downregulated after miR‑375 treatment. In conclusion, it might be possible for the level of miR‑375 expression to be a utilized as a prognostic indicator for ESCC patients. The administration of miR‑375 using a non‑viral delivery might represent a powerful new treatment for ESCC.