Hikaru Nagahara

Transduction of full-length TAT fusion proteins into mammalian cells: TAT-p27Kip1 induces cell migration.

Transduction of full-length TAT fusion proteins into mammalian cells: TAT-p27 Kip1 induces cell migration

Cell adhesion aside from integrin system can abrogate anoikis in rat liver cells by down-regulation of FasL expression, not by activation of PI-3K/Akt and ERK signaling pathway

Epithelial cells require contact with extracellular matrix (ECM) to inhibit detachment-induced apoptosis (anoikis). The ERK and PI-3K/Akt signaling pathways have been identified to inhibit anoikis. We present here a different story. An adult rat liver cell line, ARLJ301-3, underwent apoptosis within 4h under suspension conditions even with active forms of Akt and ERK1/2. Once ARLJ301-3 cells are plated on tissue culture plates coated with synthetic polymer, such as poly-(N-p-vinyl benzyl-O-beta-D-galactopyranosyl-D-gluconamide) (PVLA), poly-L-lysine or polystyrene, instead of functional ECM such as fibronectin, they could survive and proliferate without activation of Akt and ERK1/2. The expression of Fas receptor ligand (FasL) is specifically detected in cells under suspension conditions or treated with cytochalasin-D. We present here the first report that FasL expression is up-regulated by the cytoskeletal disruption directed by cytochalasin-D treatment or cell detachment from ECM.

Transdifferentiation of human fibroblasts into hepatocyte-like cells by defined transcriptional factors.

PurposeLiver transplantation is currently the only curative therapeutic option for end-stage liver cirrhosis. However, due to the limitations of donor liver availability and occasional rejection, it cannot always be successfully applied. In this study, we determined whether fibroblasts can be transdifferentiated into hepatocyte-like cells by transcription factors that initiate and maintain hepatocyte differentiation.MethodsFibroblasts were transduced with retrovirus vectors carrying FOXA2, HNF4α, and C/EBPβ. To enhance the efficiency of transdifferentiation, cMyc was also expressed.ResultsTransdifferentiation was successful using both neonatal fibroblasts and human forehead fibroblasts. The transdifferentiated cells produced hepatocyte-specific proteins such as albumin and cytochrome, and had important hepatocyte-specific functions, such as glycogen storage and indocyanine green uptake, suggesting that the cells function at least as partial hepatocytes.ConclusionsThese results provide a novel method of generating differentiated hepatocyte-like cells, and may represent an alternative source of cells for future cell-based therapeutics for end-stage liver diseases.

Efficient Induction of Apoptosis by Wee1 Kinase Inhibition in Hepatocellular Carcinoma Cells

Transforming growth factor-β1 (TGF-β1) potently inhibits human hepatocellular carcinoma (HCC) cell growth. Here we demonstrated that TGF-β1-induced apoptosis is mediated by decreased phosphorylation of cdc2 at Tyr15 accompanied by down-regulation of Wee1 kinase expression. As expected from these results, a Wee1 kinase inhibitor efficiently induced apoptosis in HCC cells in the absence of TGF-β1 treatment. In surgically resected samples, Wee1 kinase was expressed in moderately to poorly differentiated HCC, whereas no Wee1 kinase expression was observed in non-cancerous tissue, including cirrhotic tissue. Our results suggest that Wee1 kinase inhibitors may be a practical novel therapeutic option against advanced HCC.

Risk factors associated with Barrett's epithelial dysplasia.

AIM To elucidate risk factors associated with dysplasia of short-segment Barretts esophagus (BE). METHODS A total of 151 BE patients who underwent endoscopic examination from 2004 to 2008 in Aoyama Hospital, Tokyo Womens Medical University, Japan and whose diagnosis was confirmed from biopsy specimens were enrolled in the study. BE was diagnosed based on endoscopic findings of gastric-appearing mucosa or apparent columnar-lined esophagus proximal to the esophagogastric junction. Dysplasia was classified into three grades - mild, moderate and severe - according to the guidelines of the Vienna Classification System for gastrointestinal epithelial neoplasia. Anthropometric and biochemical data were analyzed to identify risk factors for BE dysplasia. The prevalence of Helicobacter pylori (H. pylori) infection and the expression of p53 by immunohistological staining were also investigated. RESULTS Histological examination classified patients into three types: specialized columnar epithelium (SCE) (n = 65); junctional (n = 38); and gastric fundic (n = 48). The incidence of dysplasia or adenocarcinoma from BE of the SCE type was significantly higher than that of the other two types (P < 0.01). The univariate analysis revealed that sex, H. pylori infection, body weight, p53 overexpression, and low diastolic blood pressure (BP) were associated with BE dysplasia. In contrast, body mass index, waist circumference, metabolic syndrome complications, and variables related to glucose or lipid metabolism were not associated with dysplasia. Multivariate logistic analysis showed that overexpression of p53 [odds ratio (OR) = 13.1, P = 0.004], H. pylori infection (OR = 0.19, P = 0.066), and diastolic BP (OR = 0.87, P = 0.021) were independent risk factors for epithelial dysplasia in BE patients with the SCE type. CONCLUSION Overexpression of p53 is a risk factor for dysplasia of BE, however, H. pylori infection and diastolic BP inversely associated with BE dysplasia might be protective.