Koshiro Harata

Expression profiling of micro-RNAs in human esophageal squamous cell carcinoma using RT-PCR

To develop novel therapeutic and diagnostic methods for esophageal cancer, it is important to understand the precise biological mechanism. Micro-RNAs (miRNAs) seem to be crucial factors in diverse regulation pathways. In this study, we analyzed the expression of mature miRNAs in esophageal squamous cell carcinoma (ESCC). The expression of 73 miRNAs was quantified by qRT-PCR in 30 primary ESCC specimens. We examined the correlation between miRNA expressions and the clinicopathological factors and prognosis of ESCC. The Kaplan-Meier survival curves showed that the high expression levels of 6 of the 72 miRNAs correlated with significantly lower patient survival rates. The overexpression of miR-129 was identified as a significant and independent prognostic factor (P = 0.031) in surgically treated ESCC patients. The hazard ratio for the prediction of early death was 18.11 for high versus low expression levels of miR-129. Similar results were obtained from an analysis performed on an additional 19 patients (test cohort) (P = 0.0057, for training cohort; P = 0.011, for test cohort; log-rank test). This experiment supports the notion that the high miR-129 expression levels, as observed in this study, might play a important role in the development of esophageal cancer.

MicroRNA-21 induces cell proliferation and invasion in esophageal squamous cell carcinoma

It has been suggested that microRNA-21 (miR-21) functions as an oncogene, as it is overexpressed in many types of tumors compared to adjacent normal tissues. However, the role of miR-21 has yet to be studied in esophageal squamous cell carcinoma (ESCC). miR-21 expression was quantified by real-time reverse transcription polymerase chain reaction in 38 ESCC specimens and their paired non-cancerous mucosa, and in 15 esophageal cancer cell lines (TE1-15). miR-21 expression levels in ESCC tissue were significantly higher than in the corresponding non-cancerous mucosa (6.873±12.664 vs. 1.000, p<0.0001). In patients with more advanced (T3 or T4) tumors, miR-21 expression levels were significantly higher than in those with less advanced (T1 or T2) tumors (P=0.0333). miR-21 expression levels in patients with more invasive infiltrative growth pattern (inf) β tumors were significantly higher than in patients with less invasive infα tumors (P=0.0166). Among the cell lines studied, TE9 had the lowest and TE1 the highest expression of miR-21. Using the miRNA precursor or antisense miRNA inhibitor, we studied how the level of miR-21 influences the proliferation of ESCC cells. Cell proliferation of the anti-miR-21-transfected cell line was significantly lower, while that of the pre-miR-21-transfected cell line was significantly higher than in the control. In ESCC, miR-21 expression may be involved in tumor growth and invasion.

Adenocarcinoma arising in a colonic interposition following a total gastrectomy: Report of a case

A segment of the transverse colon can be used for gastric reconstruction after a total gastrectomy. This report presents the case of a 68-year-old woman with primary adenocarcinoma of the colon in a segment used for reconstruction after a total gastrectomy. The interposed colon developed colon carcinoma 9 years after the gastric reconstruction. The possibility of a primary carcinoma arising in a gastric colon interposition must be considered when employing the transverse colon as a gastric substitute.

GP73 contributes to the sensitivity of cisplatin in esophageal cancer

BackgroundThe prognosis of esophageal cancer patients is poor. Cisplatin (CDDP) is most often used for advanced esophageal cancer; however, the emergence of drug resistance has prevented successful treatment in many cases.MethodsUsing microarray analysis, we identified GP73 as a candidate gene that is overexpressed in TE4, an esophageal cancer cell line which is highly resistant to CDDP. We downregulated GP73 expression in TE4 using siRNA methods. To determine the effect of reduced GP73 expression on the proliferation of TE4, we used cytotoxicity assays.ResultsDownregulation of GP73 expression using siRNA induced a significant decrease in the IC50 compared with cells treated with either control siRNA or mock transfection.ConclusionsGP73 is a candidate gene in esophageal cancer that may be the target of future molecular-targeted therapy in combination with CDDP.