Nobutaka Sato

MicroRNA-21 Regulates the Proliferation and Invasion in Esophageal Squamous Cell Carcinoma

Purpose: MicroRNAs are ∼22 nucleotide noncoding RNA molecules that posttranscriptionally regulate gene expression. The aim of this study was (a) to determine a role of microRNA-21 in esophageal squamous cell carcinoma and (b) to elucidate the regulation of the programmed cell death 4 (PDCD4) gene by microRNA-21. Experimental Design: MicroRNA-21 expression was investigated in 20 matched normal esophageal epitheliums and esophageal squamous cell carcinomas and seven esophageal squamous cell carcinoma cell lines (TE6, TE8, TE10, TE11, TE12, TE14, KYSE30) by TaqMan quantitative real-time PCR and in situ hybridization. To evaluate the role of microRNA-21, cell proliferation and invasion were analyzed with anti–microRNA-21–transfected cells. In addition, the regulation of PDCD4 by microRNA-21 was elucidated to identify the mechanisms of this regulation. Results: Of 20 paired samples, 18 cancer tissues overexpressed microRNA-21 in comparison with matched normal epitheliums. Specifically, patients with lymph node metastasis or venous invasion showed significantly high expression of microRNA-21. In situ hybridization for microRNA-21 showed strong positive staining in paraffin-embedded esophageal squamous cell carcinoma tissues. All seven esophageal squamous cell carcinoma cell lines also overexpressed microRNA-21, and anti–microRNA-21–transfected cells showed significant reduction in cellular proliferation and invasion. The PDCD4 protein levels in esophageal squamous cell carcinoma cells have an inverse correlation with microRNA-21 expression. Anti–microRNA-21–transfected cells increased PDCD4 protein expression without changing the PDCD4 mRNA level and increased a luciferase-reporter activity containing the PDCD4-3′ untranslated region construct. Conclusions: MicroRNA-21 targets PDCD4 at the posttranscriptional level and regulates cell proliferation and invasion in esophageal squamous cell carcinoma. It may serve as a novel therapeutic target in esophageal squamous cell carcinoma.

Induction chemotherapy with docetaxel/cisplatin/5-fluorouracil for patients with node-positive esophageal cancer.

Background: Despite improvements in the surgical management of esophageal cancer, the prognosis of patients with lymph node metastases is still unsatisfactory. Recently, survival benefit of neoadjuvant or induction chemotherapy for patients with esophageal cancer has been highlighted. Methods: Efficacy and toxicity of induction chemotherapy for esophageal cancer were reviewed. In addition, our experience on modified docetaxel/cisplatin/5-FU (DCF) as induction chemotherapy was also demonstrated. The modified DCF consisted of 60 mg/m2 of docetaxel on day 1, and 350 mg/m2 of 5-FU and 6 mg/m2 of cisplatin on days 1–5. Two courses have been administered as induction chemotherapy in 51 patients with node-positive esophageal cancer. Response was evaluated by RECIST v1.0 and changes in standardized uptake value by 18F-fluorodeoxyglucose positron emission tomography. Results: Induction chemotherapy may be beneficial for node-positive esophageal cancer, although the consensus has not yet been established. A regimen of induction chemotherapy should have a high response rate and cisplatin/5-FU may be underpowered as an induction setting. DCF can be a candidate for the regimen of induction chemotherapy for esophageal cancer, although severe adverse events have been reported. Several modified regimens to reduce the toxicity have been reported. The response rate of our series was 61% and a significant decrease in standardized uptake values was observed after the induction chemotherapy. Although high-grade neutropenia was still observed with this regimen, neither treatment-related death nor delay in the following treatment was observed. Conclusions: Modified DCF can be a regimen of induction chemotherapy for node-positive esophageal cancer because of its high efficacy, although an adequate care for severe neutropenia is needed.

Usefulness of Transcription–Reverse Transcription Concerted Reaction Method for Detecting Circulating Tumor Cells in Patients With Colorectal Cancer

PurposeThe CellSearch system (Veridex, LLC) is useful for detecting circulating tumor cells (CTCs) in various carcinomas, including colorectal cancer (CRC); however, there are some problems associated with its clinical use. A transcription–reverse transcription concerted reaction (TRC) method, which is a PCR-based technique producing more stable and reliable results, because it is a more simplified process compared with the conventional techniques, has been introduced for detecting micrometastasis in some carcinomas. We aimed to demonstrate the effectiveness of TRC method in the CTC detection.MethodsWe compared the two methods for the sensitivity for CTC detection using the colon cancer cell line and 42 whole-blood samples from patients with advanced or metastatic CRC. Furthermore, 25 patients with metastatic CRC were enrolled to investigate the correlation between CTC detection and prognosis in both methods.ResultsThe sensitivity of the TRC method was similar to that of the CellSearch system. The overall survival rate was significantly worse in the patients diagnosed as CTC-positive by the TRC method than in those diagnosed as CTC-negative; this finding was similar to the prognosis indicated by the CellSearch system. However, clinically, the TRC method could detect CTCs more rapidly and at a reduced cost compared with the CellSearch system.ConclusionsThe TRC method seems to be a useful alternative to the CellSearch system for clinically detecting CTCs in patients with metastatic CRC.

Extensive lymphatic spread of cancer cells in patients with thoracic esophageal squamous cell carcinoma: detection of CEA-mRNA in the three-field lymph nodes.

The aim of this study is to clarify the extent of lymphatic spread of cancer cells using a novel genetic test to examine patients with thoracic esophageal squamous cell carcinoma (ESCC).

Neuroendocrine tumor of the rectum.

The authors report a case of a neuroendocrine tumor of the rectum. A 57-year-old man was revealed to have a large tumor of the rectum with invasion to the urinary bladder and seminal capsule. After resection, the tumor was revealed to be composed of neuroendocrine cells. Adjuvant chemotherapy using cisplatin and camptothecin-11 was completed, and the patient was without recurrence 6 months after surgery.

Abstract 3749: Usefulness of Transcription-Reverse Transcription Concerted (TRC) method in detecting circulating tumor cells of patients with colorectal cancer

Background: Owing to refinement of an immunomagnetic separation technology method for count and characterization of circulating tumor cells (CTCs) in patients with epithelial malignancies has been established. CellSearch System (CSS) is a device using this technology and the significance of CSS has been reported in various carcinoma. On the other hand, as a novel PCR based techniques, the amplification system with transcription-reverse transcription concerted reaction (TRC) method was introduced for detecting a few cancer cells. This method amplifies a cancer-specific messenger RNA (mRNA) directly in a single tube at a constant temperature without thermal cycling in three steps for PCR: denaturing, annealing, and extension. Accordingly, this method may produce a more stable and reliable result because of its simplified process compared to conventional PCR-based techniques. Another advantage of TRC method over CSS is the cost. It takes 30 dollars per sample in TRC method, while the cost of CSS is 800 dollars per sample. Object: In this study, we have investigated the utility of TRC method which targeted CEA-mRNA in detecting CTCs of patients with colorectal cancer. Materials and Methods: Between Nov. 2008 and May 2009, 42 samples from metastatic and/or recurrent colorectal cancer patients (mCRC) were enrolled. We compared the detection rate of CTCs between TRC method and CSS. In CSS, CTC was considered as positive when at least one cancer cell was detected. On the other hand, in TRC method, CTCs was considered as positive when the result of TRC method was positive. The statistical significance was evaluated by chi-square test. Differences were considered to be statistically significant when the p-value was less than 0.05. Results: In CSS, 27 samples (64.3%) were CTC positive, while 16 samples (38.1%) were CTC positive by TRC method. All of samples which are CTC positive by TRC method were also CTC positive by CSS. In order to compensate the lower sensitivity of TRC method, we have taken serum CEA value into account. As a result, all samples negative for TRC method but positive for CSS were from the patients whose serum CEA value was more than 20 ng/ml. In contrast, when serum CEA value of the patients was less than 20 ng/ml, all samples negative for TRC method demonstrated CTC negative for CSS. These results indicate that CSS should be done only when the sample from patients whose serum CEA value is more than 20 ng/ml is negative for TRC method. Conclusions: In conclusion, combination with TRC method and serum CEA evaluation can reduce the necessity of CSS analysis and thus reduce the cost of detecting CTCs. 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 3749.