Claudin-1 induces epithelial-mesenchymal transition through activation of the c-Abl-ERK signaling pathway in human liver cells.

Claudins (CLDNs) are a family of integral membrane proteins central to the formation of tight junctions, structures that are involved in paracellular transport and cellular growth and differentiation, and are critical for the maintenance of cellular polarity. Recent studies have provided evidence that CLDNs are aberrantly expressed in diverse types of human cancers, including hepatocellular carcinomas (HCCs). However, little is known about how CLDN expression is involved in cancer progression. In this study, we show that CLDN1 has a causal role in the epithelial-mesenchymal transition (EMT) in human liver cells, and that the c-Abl-Ras-Raf-1-ERK1/2 signaling axis is critical for the induction of malignant progression by CLDN1. Overexpression of CLDN1 induced expression of the EMT-regulating transcription factors Slug and Zeb1, and thereby led to repression of E-cadherin, ß-catenin expression, enhanced expression of N-cadherin and Vimentin, a loss of cell adhesion, and increased cell motility in normal liver cells and HCC cells. In line with these findings, inhibition of either c-Abl or ERK clearly attenuated CLDN1-induced EMT, as evidenced by a reversal of N-cadherin and E-cadherin expression patterns, and restored normal motility. Collectively, these results indicate that CLDN1 is necessary for the induction of EMT in human liver cells, and that activation of the c-Abl-Ras-Raf-1-ERK1/2 signaling pathway is required for CLDN1-induced acquisition of the malignant phenotype. The present observations suggest that CLDN1 could be exploited as a biomarker for liver cancer metastasis and might provide a pivotal point for therapeutic intervention in HCC.

c-Jun N-terminal kinase has a pivotal role in the maintenance of self-renewal and tumorigenicity in glioma stem-like cells.

Uncovering the mechanisms that govern the maintenance of stem-like cancer cells is critical for developing therapeutic strategies for targeting these cells. Constitutive activation of c-Jun N-terminal kinase (JNK) has been reported in gliomas and correlates with histological grade. Here, we found that JNK signaling is crucial for the maintenance of 'stemness' in glioma cells. Sphere-cultured glioma cells showed more phosphorylation of JNK compared with serum-containing monolayer cultures. Importantly, blockade of JNK signaling with SP600125 or small interfering RNAs targeting JNK1 or JNK2 significantly reduced the CD133(+)/Nestin(+) population and suppressed sphere formation, colony formation in soft agar, and expression of stem cell markers in sphere-cultured glioma cells. Intriguingly, sphere-cultured glioma cells exhibited enhanced expression of Notch-2, but not Notch-1, -3 or -4, and JNK inhibition almost completely abrogated this increase. Blocking the phosphoinoside 3-kinase (PI3K)/Akt pathway with LY294002 or si-Akt also suppressed the self-renewal of sphere-cultured glioma cells. PI3K, but not Akt, had a role as an upstream kinase in JNK1/2 activation. In addition, treatment with si-JNK greatly increased etoposide- and ionizing radiation (IR)-induced cell death in glioma spheres. Consistent with glioma cell lines, glioma stem-like cells isolated from primary patient glioma cells also had a higher activity of JNK and Notch-2 expression. Importantly, inhibition of JNK2 led to a decrease of Notch-2 expression and suppressed the CD133(+)/Nestin(+) cell population in patient-derived primary glioma cells. Finally, downregulation of JNK2 almost completely suppressed intracranial tumor formation by glioma cells in nude mice. Taken together, these data demonstrate that JNK signaling is crucial for the maintenance of self-renewal and tumorigenicity of glioma stem-like cells and drug/IR resistance, and can be considered a promising target for eliminating stem-like cancer cells in gliomas.

Hdm2 negatively regulates telomerase activity by functioning as an E3 ligase of hTERT.

In this study, we identified posttranslational regulation of human telomerase reverse-transcriptase (hTERT) by the E3 ligase Hdm2. The telomerase activity generated by exogenous hTERT in U2OS cells was reduced on adriamycin treatment. The overexpressed levels of hTERT were also decreased under the same conditions. These processes were reversed by treatment with a proteasome inhibitor or depletion of Hdm2. Furthermore, intrinsic telomerase activity was increased in HCT116 cells with ablation of Hdm2. Immunoprecipitation analyses showed that hTERT and Hdm2 bound to each other in multiple domains. Ubiquitination analyses showed that Hdm2 could polyubiquitinate hTERT principally at the N-terminus, which was further degraded in a proteasome-dependent manner. An hTERT mutant with all five lysine residues at the N-terminus of hTERT that mutated to arginine became resistant to Hdm2-mediated ubiquitination and degradation. In U2OS cells, depletion of Hdm2 or addition of the Hdm2-resistant hTERT mutant strengthened the cellular protective effects against apoptosis. Similar results were obtained with the Hdm2-stable H1299 cell line. These observations indicate that Hdm2 is an E3 ligase of hTERT.

High isolation rate of adenovirus serotype 7 from South Korean military recruits with mild acute respiratory disease.

Adenovirus is a major cause of acute respiratory disease (ARD) in military recruits. When South Korean military recruits with ARD were surveyed, adenovirus was identified in 122 (61.0%) of the 200 recruits studied. Moreover, all cases of ARD involving adenovirus were caused by serotype 7.

EBV-associated haemophagocytic syndrome in a patient with Behçet's disease.

We present a case of Epstein-Barr virus (EBV)-associated haemophagocytic syndrome in a patient with Behçet's disease. A 43-year-old man, who had been receiving treatment under the diagnosis of Behçet's disease for recurrent oral ulcers, genital ulcer, ileal ulcer, and arthritis, had been admitted for fever, headache, and nausea developed 3 days ago. Laboratory data showed pancytopaenia, an increase in liver enzymes, lactate dehydrogenase (LDH) and ferritin. Haemophagocytic syndrome was diagnosed from histiocytosis and haemophagocytosis by macrophages, shown in the bone marrow aspiration and biopsy, and in situ hybridization for EBV showed a positive finding. The patient recovered rapidly after steroid therapy. This is the first report of EBV-associated haemophagocytic syndrome developed in a patient with Behçet's disease.

Various applications of titanium mesh screen implant to orbital wall fractures.

As the number of high velocity injuries increases, orbital wall fractures that involve other facial bone fractures, especially those showing multiple crushed fractures have become increasingly common. However, owing to its complex anatomic structure, our inability to visualize details and relatively thin orbital wall, corrective restorations and fixations are very difficult. Recently several reports have claimed good results using titanium implants to repair orbital fracture. Over a period of 36 months, Titanium mesh screen 1.0 (SYNTHES) were applied to the repair of orbital fracture in various ways, taking 39 examples of orbital wall fracture patients requiring operating treatment. A titanium mesh screen 1.0 was used either as an onlay implant after it was shaped to fit the anatomical shape of the fracture portion, or as cover implant to fix bony pieces after repairing a severely crushed fracture on the orbital rim or maxillary wall segments. 1.3-mm micro-screws were used to fix the titanium mesh screen when needed. The titanium mesh screen 1.0 was rigid, yet malleable enough to get the desired shape. It could be folded and screwed easily, and was also easy for follow-up with fewer artifacts on the CT findings. Therefore, we could restore and fix much easier and faster even crushed tiny bony pieces without loss and achieve more accurate three-dimensional anatomical reconstruction of orbital wall fracture.

Intussusception in children: US-guided pneumatic reduction--initial experience.

PURPOSE: To assess the feasibility and effectiveness of ultrasonography (US)-guided pneumatic reduction of intussusception in children. MATERIALS AND METHODS: The study group consisted of 49 consecutive patients (aged 2 months to 7 years; 36 boys, 13 girls) who underwent 52 reductions of intussusception during 9 months. Intussusception was diagnosed in all patients with the known US criteria, and all patients underwent a US-guided pneumatic reduction attempt wholly within the US examination room. A pressure of 60 mm Hg was maintained for 30 seconds, with US guidance. The procedure was considered to be successful when US showed the disappearance of the intussusceptum and the edematous terminal ileum with an abrupt transition into the normal proximal ileum. When the intussusception was not reduced, the procedure was repeated, with pressure increased to 120 mm Hg. RESULTS: The overall success rate of US-guided pneumatic reduction was 92% (48 of 52 reductions), with no immediate recurrence. Of the two patients who had intussusceptions that were irreducible, one had residual ileoileal intussusception at surgery, and the other had an ileal polyp as a lead point. Perforation occurred in two (4%) of 52 cases; one patient underwent right hemicolectomy due to bowel necrosis and had a pinpoint perforation in the normal proximal transverse colon, and the other underwent manual reduction of ileoileocolic intussusception, with microperforation in the proximal transverse colon. CONCLUSION: US-guided pneumatic reduction seems to be a feasible and effective method for the treatment of intussusception in children because of its radiation-sparing effect and high success rate.

Requirements of multiple domains of SLI-1, a Caenorhabditis elegans homologue of c-Cbl, and an inhibitory tyrosine in LET-23 in regulating vulval differentiation.

SLI-1, a Caenorhabditis elegans homologue of the proto-oncogene product c-Cbl, is a negative regulator of LET-23-mediated vulval differentiation. Lack of SLI-1 activity can compensate for decreased function of the LET-23 epidermal growth factor receptor, the SEM-5 adaptor, but not the LET-60 RAS, suggesting that SLI-1 acts before RAS activation. SLI-1 and c-Cbl comprise an N-terminal region (termed SLI-1:N/Cbl-N, containing a four-helix bundle, an EF hand calcium-binding domain, and a divergent SH2 domain) followed by a RING finger domain and a proline-rich C-terminus. In a transgenic functional assay, the proline-rich C-terminal domain is not essential for sli-1(+) function. A protein lacking the SH2 and RING finger domains has no activity, but a chimeric protein with the SH2 and RING finger domains of SLI-1 replaced by the equivalent domains of c-Cbl has activity. The RING finger domain of c-Cbl has been shown recently to enhance ubiquitination of active RTKs by acting as an E3 ubiquitin-protein ligase. We find that the RING finger domain of SLI-1 is partially dispensable. Further, we identify an inhibitory tyrosine of LET-23 requiring sli-1(+) for its effects: removal of this tyrosine closely mimics the loss of sli-1 but not of another negative regulator, ark-1. Thus, we suggest that this inhibitory tyrosine mediates its effects through SLI-1, which in turn inhibits signaling upstream of LET-60 RAS in a manner not wholly dependent on the ubiquitin-ligase domain.

Immature gastric teratoma in an infant: a case report.

Gastric teratomas are extremely rare neoplasms and almost exclusively benign. They occur predominantly in males and generally present as a palpable abdominal mass. To our knowledge, only one adult case has been described in the Korean literature. We report a case in which an immature gastric teratoma in a 3-month-old boy was revealed by CT and US.

The prevalence of congenital inverted nipple.

To investigate the prevalence and type of congenital inverted nipple, and realizing that the condition is a disease for which treatment is necessary, 1,625 unmarried women aged between 19 and 26 were physically examined and responded to questions about inverted nipple. Fifty-three of 1,625 subjects (3.26%) presented with this malformation, and it was found in 3.05% of the 3,250 nipples examined. In 46 of the 53 (86.79%), the condition was bilateral, and in 7 (13.21%), it was unilateral. In such cases, inversion was found on the right side in two subjects and on the left side in five. Of the total number of congenital inverted nipples, 96.23% were umbilicated and 3.77% were invaginated. Nine of the 53 subjects with inverted nipple considered that the condition should be corrected. Prior to counseling and possible surgery, the medical practitioner must carefully consider all available information, and the data contained in this report may thus be useful.

Topographically specific effects of ELF-1 on retinal axon guidance in vitro and retinal axon mapping in vivo.

Topographic maps, which maintain the spatial order of neurons in the order of their axonal connections, are found throughout the nervous system. In the visual retinotectal projection, ELF-1, a ligand in the tectum, and its receptors in the retina show complementary gradients in expression and binding, indicating they may be positional labels for map development. Here we show that ELF-1 acts as a repellent axon guidance factor in vitro. In vivo, when the tectal ELF-1 pattern is modified by retroviral overexpression, retinal axons avoid ectopic ELF-1 patches and map to abnormally anterior positions. All these effects were seen on axons from temporal but not nasal retina, indicating that ELF-1 could determine nasal versus temporal retinotectal specificity, and providing a direct demonstration of a cell recognition molecule with topographically specific effects on neural map development.

Similarity of sli-1, a regulator of vulval development in C. elegans, to the mammalian proto-oncogene c-cbl.

Vulval induction during Caenorhabditis elegans development is mediated by LET-23, a homolog of the mammalian epidermal growth factor receptor tyrosine kinase. The sli-1 gene is a negative regulator of LET-23 and is shown here to encode a protein similar to c-Cbl, a mammalian proto-oncoprotein. SLI-1 and c-Cbl share approximately 55 percent amino acid identity over a stretch of 390 residues, which includes a C3HC4 zinc-binding motif known as the RING finger, and multiple consensus binding sites for Src homology 3 (SH3) domains. SLI-1 and c-Cbl may define a new class of proteins that modify receptor tyrosine kinase-mediated signal transduction.

Immunohistochemical and biochemical identification of pepsinogen isozymes in the hamster lungs: induction by polychlorinated biphenyls.

Pepsinogens are acid protease enzymes of pepsin usually found in gastric mucosa. In the present study, we demonstrated the presence of pepsinogen isozymes in male Syrian golden hamster lung tissues by a combined immunohistochemical and biochemical approach. Immunohistochemically, using rat pepsinogen 1 antibody, pepsinogen positive cells were observed mainly in the epithelia of the terminal bronchioles. They demonstrated morphological features of Clara cells. The pepsinogen isozyme pattern of lung tissue determined by polyacrylamide gel electrophoresis was similar to that of stomach mucosa. Treatment of hamsters with polychlorinated biphenyls at a dose of 500 mg/kg body weight ip caused a 2.8-fold increase in pepsinogen content (p less than 0.01) as well as increase in numbers of pepsinogen positive cells in the lung.