Embryonic stem (ES) cells are a promising source of cardiomyocytes, but clinical application of ES cells has been hindered by the lack of reliable selective differentiation methods. Differentiation into any lineage is partly dependent on the regulatory mechanisms of normal early development. Although several signals, including bone morphogenetic protein (BMP), Wnt and FGF, are involved in heart development, scarce evidence is available about the exact signals that mediate cardiomyocyte differentiation. While investigating the involvement of BMP signaling in early heart formation in the mouse, we found that the BMP antagonist Noggin is transiently but strongly expressed in the heart-forming region during gastrulation and acts at the level of induction of mesendoderm to establish conditions conducive to cardiogenesis. We applied this finding to develop an effective protocol for obtaining cardiomyocytes from mouse ES cells by inhibition of BMP signaling.

Background-Periostin is highly expressed in the myocardium in patients with heart failure. However, no report has documented the function of periostin. To identify the function of periostin in the pathophysiology of heart failure, overexpression or loss of function of the periostin gene was examined by direct transfection into the rat heart. Methods and Results-Rats transfected with the periostin gene by the HVJ-liposome method showed left ventricular (LV) dilation as assessed by echocardiography, accompanied by an increase in periostin expression. Consistently significant differences were observed in LV pressure, LV end-diastolic pressure, LV dP/dt max , and LV dP/dt min at 6 and 12 weeks after transfection in rats transfected with the periostin gene, accompanied by a decrease in cardiac myocytes and an increase in collagen deposition. Importantly, periostin has the ability to inhibit the spreading of myocytes and the adhesion of cardiac fibroblasts with or without fibronectin. Markers of cardiac dysfunction such as brain natriuretic peptide and endothelin-1 gene expression were significantly increased after transfection in the LV of rats transfected with the periostin gene. These data demonstrate that overexpression of the periostin gene led to cardiac dysfunction. Thus, we examined the inhibition of periostin in Dahl salt-sensitive rats by an antisense strategy because periostin is highly expressed in heart failure. Importantly, inhibition of periostin gene expression resulted in a significant increase in survival rate, accompanied by an improvement of LV function. Conclusion-The present study demonstrates the contribution of the periostin gene to cardiac dilation in animal models.Inhibition of periostin might become a new therapeutic target for the treatment of heart failure.

Escherichia coli cells were found to contain a novel outer membrane-associated protease, designated protease VII (K. Sugimura and N. Higashi, J. Bacteriol. 170:3650-3654, 1988). This enzyme was purified to homogeneity and exhibited an apparent molecular weight of 36,000 on sodium dodecyl sulfate gels and 180,000 on a TSK G-3000SW column in the presence of Triton X-100. It was capable of cleaving several peptides at the center of paired basic residues but not at single basic residues, implying that it is distinct from trypsinlike proteases. Protease VII was most active at pH 6.0 and was sensitive to a serine protease inhibitor, diisopropylfluorophosphate, and to the bivalent cations Zn2+, Cu2+, and Fe2+. The nucleotide sequence of a protease VII gene-carrying DNA fragment, which had been cloned by complementation analysis (K. Sugimura, Biochem. Biophys. Res. Commun. 153:753-759, 1988) was determined. It carried two putative promoter regions and a putative Shine-Dalgarno sequence in addition to the complete structural gene, which encoded pre-protease VII of 317 amino acid residues, with the N-terminal 20 residues being a signal peptide. By comparing their amino acid sequences, protease VII and OmpT, which specifically cleaves ferric enterobactin receptor protein, were found to be identical.

Purpose: Cisplatin-based chemotherapy is widely used for esophageal cancer, sometimes in combination with surgery/radiotherapy, but poor response to chemotherapy is not uncommon. The aim of this study was to examine whether miRNA expression is useful to predict the response to chemotherapy in patients with esophageal cancer.Experimental Design: Using pretreatment biopsy samples from 98 patients with esophageal cancer who received preoperative chemotherapy, we measured the expression level of several miRNAs whose expression was altered in cisplatin-resistant esophageal cancer cell lines compared with those parent cell lines and examined the relationship between the miRNA expression and response to chemotherapy. In vitro assays were conducted to clarify the mechanism of miRNA-induced changes in chemosensitivity.Results: The expression levels of 15 miRNAs were altered in cisplatin-resistant cells. Of these, low expression of let-7b and let-7c in before-treatment biopsies from 74 patients of the training set correlated significantly with poor response to chemotherapy, both clinically and histopathologically. Low expression of let-7c also correlated with poor prognosis (P ¼ 0.032). The relationship between let-7b and let-7c expression and response to chemotherapy was confirmed in the other 24 patients of the validation set. In in vitro assay, transfection of let-7c restored sensitivity to cisplatin and increased rate of apoptosis after exposure to cisplatin. Let-7c directly repressed cisplatin-activated interleukin (IL)-6/STAT3 prosurvival pathway.Conclusions: Let-7 expression in esophageal cancer can be potentially used to predict the response to cisplatin-based chemotherapy. Let-7 modulates the chemosensitivity to cisplatin through the regulation of IL-6/STAT3 pathway in esophageal cancer.

Infiltration of TAMs, especially M2 macrophages, is associated with a poor response to chemotherapy and poor prognosis of patients with esophageal cancer.

There is increasing evidence that the expression of microRNA (miRNA) in cancer is associated with chemosensitivity but the mechanism of miRNA-induced chemoresistance has not been fully elucidated. The aim of this study was to examine the role of extracellular miRNA in the response to chemotherapy in esophageal cancer. First, serum expression of miRNAs selected by miRNA array was measured by quantitative reverse transcription-polymerase chain reaction in 68 patients with esophageal cancer who received cisplatin-based chemotherapy to examine the relationship between miRNA expression and response to chemotherapy. The serum expression levels of 18 miRNAs were different between responders and non-responders by miRNA array. Of these, high expression levels of miR-27a/b correlated with poor response to chemotherapy in patients with esophageal cancer. Next, in vitro assays were conducted to investigate the mechanism of miRNA-induced chemoresistance. Although transfection of miR-27a/b to cancer cells had no significant impact on chemosensitivity, esophageal cancer cells cultured in supernatant of miR-27a/b-transfected normal fibroblast showed reduced chemosensitivity to cisplatin, compared with cancer cells cultured in supernatant of normal fibroblast. MiR-27a/b-transfected normal fibroblast showed α-smooth muscle actin (α-SMA) expression, a marker of cancer-associated fibroblasts (CAF) and increased production of transforming growth factor-β (TGF-β). Chemosensitivity recovered after administration of neutralizing antibody of TGF-β to the supernatant transfer experiments. Our results indicated that miR-27a/b is involved in resistance to chemotherapy in esophageal cancer, through miR-27a/b-induced transformation of normal fibroblast into CAF.

The serum level of miR-200c can be useful for predicting the response to chemotherapy and the prognosis of patients with esophageal cancer who receive neoadjuvant chemotherapy.

Background:Lin28 is a negative regulator of the tumour suppressor microRNA, let-7, suggesting its role in tumourigenesis. However, the clinical significance of Lin28 expression in oesophageal cancer has not been elucidated.Methods:Lin28 and Lin28B expression was examined by immunohistochemistry in 161 tissues from patients with oesophageal cancer who had undergone curative surgery. The relationship between the expressions of Lin28 and Lin28B and various clinicopathological factors was examined. In vitro assays were conducted to determine the role of Lin28 in aggressiveness of oesophageal cancers using oesophageal cancer cell line.Results:Lin28 and Lin28B were overexpressed in oesophageal cancer cells compared with non-cancerous epithelial cells, especially in the invasive front. High expression of Lin28 and Lin28B correlated significantly with lymph node metastasis and poor prognosis. High expression of Lin28B expression correlated significantly with low expression of let-7. Multivariate analysis also identified Lin28B expression as an independent prognostic factor. In vitro assays showed that the proliferative and invasive activities were significantly reduced in Lin28B-knockdown cells, compared with control cells.Conclusion:High expression of Lin28 is associated with poor prognosis and high tumour aggressiveness in oesophageal cancer and these effects are mediated through increased proliferation and invasiveness of oesophageal cancer cells.