Adipocytes contribute to tumor progression and invasion of peritoneal metastasis by interacting with gastric cancer cells as cancer associated fibroblasts.

BACKGROUND: Peritoneal metastasis (PM) is one of the most common causes of noncurative surgery and the most frequent recurrence pattern in gastric cancer (GC). During the process of PM, GC cells detached from primary tumor interact with human peritoneal mesothelial cells (HPMC) overlapped with adipose tissues such as the omentum or mesentery. Although the interaction with HPMC promotes the malignancy of GC, the role of adipose tissues remains unclear. AIMS: We aimed to clarify how adipose tissue are affected by adjacent primary tumors during the expression of adipokines and to elucidate whether GC cells transform adipocytes into CAFs in vitro. In addition, we investigated whether GC cells are affected by adipocytes in their ability to infiltrate. METHODS: We investigated the phenotypic conversion of adipocytes during the malignant process of GC cells in vivo and in vitro. We evaluated the expression levels of adiponectin in the omental adipose tissue of gastric cancer patients by western blotting. Following adipocytes/gastric cancer cells coculture, adipocyte markers, adiponectin receptors, and inflammatory cytokine markers were detected by real-time PCR and/or western blotting in the single-cultured and co-cultured adipocytes; cancer-associated fibroblast (CAF) markers were detected by immunofluorescence and western blotting in the single-cultured and co-cultured adipocytes; invasion assays were performed in single cultured and co-cultured MKN45 and OCUM. RESULTS: In omental adipose tissues that are situated close to the primary tumors, the expression of adiponectin tended to decrease in patients with subserosal or serosal invasion. By co-culturing with GC cells, adipocytes were dedifferentiated and the expression levels of CAF marker FSP1 and inflammatory cytokines, PAI-1 and IL-6, significantly increased (p < 0.05). Furthermore, GC cells co-cultured with adipocytes showed enhanced invasion ability. CONCLUSION: Our findings suggest that the phenotypic conversion of adipocytes may promote the malignancy of GC in the construction of the cancer microenvironment of PM.

Glial cell type-specific gene expression in the mouse cerebrum using the piggyBac system and in utero electroporation.

Glial cells such as astrocytes and oligodendrocytes play crucial roles in the central nervous system. To investigate the molecular mechanisms underlying the development and the biological functions of glial cells, simple and rapid techniques for glial cell-specific genetic manipulation in the mouse cerebrum would be valuable. Here we uncovered that the Gfa2 promoter is suitable for selective gene expression in astrocytes when used with the piggyBac system and in utero electroporation. In contrast, the Blbp promoter, which has been used to induce astrocyte-specific gene expression in transgenic mice, did not result in astrocyte-specific gene expression. We also identified the Plp1 and Mbp promoters could be used with the piggyBac system and in utero electroporation to induce selective gene expression in oligodendrocytes. Furthermore, using our technique, neuron-astrocyte or neuron-oligodendrocyte interactions can be visualized by labeling neurons, astrocytes and oligodendrocytes differentially. Our study provides a fundamental basis for specific transgene expression in astrocytes and/or oligodendrocytes in the mouse cerebrum.

The role of peripheral corticotropin-releasing factor signaling in a rat model of stress-induced gastric hyperalgesia.

BACKGROUND: Functional dyspepsia (FD) is a common gastrointestinal disorder associated with persistent or recurrent upper gastrointestinal tract symptoms such as pain without any obvious pathological changes. Psychological and psychiatric factors might have a pathogenic role in FD. Changes in the sensation of stomach pain were determined after application of stress to adult rats. The involvement of corticotropin-releasing factor (CRF), Type 2 CRF receptor (CRF2) and inflammatory cytokine interleukin-6 (IL-6) was also investigated in the gastric hyperalgesia observed in this model. RESULTS: Repeated water avoidance stress (WA-S) produced gastric hyperalgesia, with no obvious lesions in the gastric mucosa. Gastric hyperalgesia was inhibited by CRF and CRF2 antagonists, suggesting their involvement in gastric hyperalgesia observed after application of stress. Gastric hyperalgesia was inhibited by IL-6 neutralizing antibody. Immunofluorescence staining demonstrated CRF, CRF2, urocortin (Ucn)1, and Ucn2-positive cells in the gastric mucosa. CRF2-positive cells increased after WA-S, compared to sham stress. CRF2 and Ucn2 were expressed in the mast cells in the gastric mucosa. CONCLUSIONS: CRF2 plays an important role in gastric hyperalgesia produced by stress. CRF2 signaling may be a useful therapeutic target for functional dyspepsia.

Phosphodiesterase III inhibitor attenuates rat sinusoidal obstruction syndrome through inhibition of platelet aggregation in Disse's space.

BACKGROUND AND AIM: Sinusoidal obstruction syndrome (SOS) is a serious drug-induced liver injury. However, the pathophysiology of the disease remains unclear. This study investigated the effects of cilostazol (CZ), a phosphodiesterase III inhibitor, in a monocrotaline (MCT)-induced rat model of SOS. METHODS: Male Wistar rats were administrated MCT to induce SOS. Rats were divided into control, MCT, and MCT + CZ groups. In the MCT + CZ group, CZ was administered at 48 h, 24 h, and 30 min prior to and 8 h and 24 h after MCT administration. The MCT group was treated with water instead of CZ. At 48 h after MCT administration, blood and liver samples were collected to assess biochemistry and liver histology. Expression of rat endothelial cell antigen, CD34, CD41, P-selectin, and caspase-3 in the liver were analyzed. Plasminogen activator inhibitor-1 (PAI-1) in hepatocytes was analyzed using western blotting and polymerase chain reaction. RESULTS: In the MCT group, macroscopic findings showed a dark-red liver surface. Histological findings showed sinusoidal dilatation, coagulative necrosis of hepatocytes, and endothelial damage of the central vein. These changes were attenuated in the MCT + CZ group. Elevated serum transaminase and decreased platelet counts were observed in the MCT + CZ group compared with those in the MCT group. Treatment with CZ reduced MCT-induced damage to the liver sinusoidal endothelial cells, inhibited extravasated platelet aggregation, and suppressed hepatocyte apoptosis around the central vein. CZ attenuated hepatic PAI-1 protein and mRNA levels. CONCLUSIONS: Cilostazol attenuated MCT-induced SOS by preventing damage to liver sinusoidal endothelial cells and extravasated platelet aggregation. Hepatic PAI-1 levels were suppressed with CZ treatment.

Chemoprevention of esophageal adenocarcinoma in a rat model by ursodeoxycholic acid.

Reflux of bile acid into the esophagus induces esophagitis, inflammation-stimulated hyperplasia, metaplasia such as Barrett's esophagus (BE), and esophageal adenocarcinoma (EAC). Caudal-type homeobox 2 (Cdx2) via nuclear factor (NF)-κB induced by bile acid is an important factor in the development of BE and EAC. In colorectal cancer, experimental data suggest a chemopreventive effect of ursodeoxycholic acid (UDCA). We hypothesized that UDCA may protect against the esophageal inflammation-metaplasia-carcinoma sequence by decreasing the overall proportion of the toxic bile acids. Wistar male rats that underwent a duodenoesophageal reflux procedure were divided into two groups. One group was given commercial chow (control group), and the other was given experimental chow containing UDCA (UDCA group). The animals were killed at 40 weeks after surgery, and their bile and esophagus were examined. In the UDCA group, the esophagitis was milder and the incidence of BE was significantly lower (p < 0.05) than in the control group, and EAC was not observed (p < 0.05). In analysis of the compartment of bile acid, UDCA was markedly increased in the UDCA group compared with the control group (32.7 ± 11.4 vs. 0.82 ± 0.33 mmol/L, p < 0.05) and cholic acid was decreased (32.7 ± 4.05 vs. 60.9 ± 8.26 mmol/L, p < 0.05). Expression intensity of Cdx2 and NF-κB was greater in the control group than in the UDCA group (p < 0.05). UDCA may be a chemopreventive agent against EAC by varying the bile acid composition.

Validated Liquid Culture Monitoring System for Lifespan Extension of Caenorhabditis elegans through Genetic and Dietary Manipulations.

Nutritional and genetic factors influence aging and life expectancy. The reduction of food intake without malnutrition, referred to caloric restriction (CR), has been shown to increase lifespan in a wide variety of species. The nematode Caenorhabditis elegans (C. elegans) is one of the principle models with which to study the biology of aging and search for anti-aging compounds. In this study, we validated and optimized a high-throughput liquid culture system to monitor C. elegans lifespan with minimized mechanical stress. We used alive and ultraviolet (UV)-killed Escherichia coli (E. coli) OP50 at 10(8) or 10(9) colony-forming units (cfu)/ml to feed Bristol N2 wild-type (WT) and mutant worms of a well-characterized insulin/insulin-like growth factor signaling (ILS) pathway: the insulin receptor homolog daf-2 (e1370), phosphatidylinositol 3-kinase age-1 (hx546), and transcriptional factor FOXO homolog daf-16 (mu86 and mgDf50). Compared with alive E. coli at 10(9) cfu/ml, supplementations of alive E. coli at 10(8) cfu/ml or UV-killed E. coli at 10(9) cfu/ml dramatically prolonged lifespan in WT and age-1 mutants, and to a lesser extent, in daf-2 and daf-16 mutants, suggesting that signaling pathways in CR and ILS do not overlap fully. Feeding 10(8) cfu/ml UV-killed E. coli, which led to maximally saturated longevity in WT and daf-2 mutant, can prolonged lifespan in age-1, but not daf-16, mutants. This approach will be useful for investigating the biology of aging, physiological responses and gene functions under CR conditions and also for screening pharmacologic compounds to extend lifespan or affect other biologic processes.

Formulation study of topically applied O/W lotion containing vitamin D3 derivative, focusing on skin permeability of the drug.

Permeation of 22-oxacalcitriol-1α, 25-dihydroxyvitamin D(3) (OCT) through excited hairless mouse skin was determined after application of OCT as solutions and O/W lotions consisted of different polarities of solvents: medium-chain fatty acid triglyceride (MCT), myristate isopropyl (IPM), 1,3-butylene glycol (1,3-BG), and propylene glycol (PG). OCT concentration in skin was also followed after applying these formulations. A two-layer diffusion model was composed to analyze dermatopharmacokinetic profiles of OCT for each vehicle. In the OCT solutions, skin permeation profile of OCT differed depending on solvent polarity. The O/W lotion with a high MCT content led to a low amount of OCT in skin. On the other hand, the O/W lotion with a high 1,3-BG content led to a high amount of OCT in skin. This dermatopharmacokinetic analysis indicated that addition of MCT to the formulation decreases the skin/vehicle partition coefficient of OCT and increases the diffusion coefficient of OCT in skin. However, the opposite effects on these two parameters were found in the case of 1,3-BG. Thus, skin permeability of OCT differed depending on the solvents used in the formulation. These results indicate that skin permeability of OCT is influenced by the physicochemical properties (i.e. polarity) of OCT, solvent, and skin. Our findings on the solvent effects of the skin permeability of OCT are thus useful for designing topical drug formulation, especially in aiming for bioequivalent dosage formulas.

Tumor-derived trypsin enhances proliferation of intrahepatic cholangiocarcinoma cells by activating protease-activated receptor-2.

In primary malignant liver tumors, trypsinogen-immunoreactivity was present in 70% of intrahepatic cholangiocarcinoma (ICC) specimens, but absent in hepatocellular carcinoma (HCC) specimens. We suggest the secretion of trypsinogen to be a key difference in biological behavior between ICC and HCC cells. The purpose of this study was to investigate the secretion of tumor-derived trypsin and the expression of its specific receptor, protease-activated receptor-2 (PAR-2), in ICC using cell lines and surgical specimens. The expression of trypsinogen-1 mRNA was observed in three of four ICC cell lines, but none of three HCC cell lines. Western blot analysis detected trypsinogen-1 in serum-free conditioned medium from one of the ICC cell lines positive for the mRNA. Gelatin zymography revealed a gelatinolytic activity for trypsin, the activated form of trypsinogen, in the same conditioned medium. PAR-2 mRNA and protein were observed in ICC cell lines. The proliferative activity of ICC cells was increased by concentrations of trypsin as low as 10 nM, and peaked at 100 nM. The effect of trypsin was suppressed by a serine protease inhibitor, gabexate mesilate. PAR-2 expression was detected in 64% of ICC surgical specimens immunohistochemically. In addition, stroma fibroblasts expressed PAR-2 in 52% of ICC specimens. These results suggest that trypsinogen-1 contributes to the growth of ICC cells and also tumor-associated fibroblasts.

Regulation of alternative splicing of the receptor for advanced glycation endproducts (RAGE) through G-rich cis-elements and heterogenous nuclear ribonucleoprotein H.

Receptor for advanced glycation endproducts (RAGE) is a cell-surface receptor. The binding of ligands to membrane-bound RAGE (mRAGE) evokes cellular responses involved in various pathological processes. Previously, we identified a novel soluble form, endogenous secretory RAGE (esRAGE) generated by alternative 5' splice site selection in intron 9 that leads to extension of exon 9 (exon 9B). Because esRAGE works as an antagonistic decoy receptor, the elucidation of regulatory mechanism of the alternative splicing is important to understand RAGE-related pathological processes. Here, we identified G-rich cis-elements within exon 9B for regulation of the alternative splicing using a RAGE minigene. Mutagenesis of the G-rich cis-elements caused a drastic increase in the esRAGE/mRAGE ratio in the minigene-transfected cells and in loss of binding of the RNA motif to heterogenous nuclear ribonucleoprotein (hnRNP) H. On the other hand, the artificial introduction of a G-stretch in exon 9B caused a drastic decrease in the esRAGE/mRAGE ratio accompanied by the binding of hnRNP H to the RNA motif. Thus, the G-stretches within exon 9B regulate RAGE alternative splicing via interaction with hnRNP H. The findings should provide a molecular basis for the development of medicines for RAGE-related disorders that could modulate esRAGE/mRAGE ratio.

Effect of porto-systemic shunting on NOS expression after extended hepatectomy in rats.

AIM: Several surgical procedures have been developed for reducing portal vein pressure to prevent postoperative liver injury. Nitric oxide synthase expression (NOS) induced by elevation of portal vein pressure is thought to play an important role in liver regeneration, but the details are not well understood. METHODS: Rats in the control group and in the subcutaneous splenic transposition (SST) group underwent 90% partial hepatectomy. Survival and portal vein pressure were analyzed. The serum IL-6 and TNF-alpha levels were measured by enzyme-linked immunosorbent assay (ELISA). Hepatocyte proliferation and apoptosis 12 hours after hepatectomy were analyzed immunohistochemically. The protein and messenger RNA expression of inducible and endothelial NOS were analyzed using Western blotting and quantitative reverse transcriptase polymerase chain reaction, respectively. RESULTS: The survival rate of the SST group was significantly higher. Portal vein pressure, TNF-alpha level and the apoptotic index were significantly lower in the SST group. Twelve hours after surgery, liver inducible NOS (iNOS) protein expression was significantly lower in the SST group. However, protein expression of endothelial NOS was not significantly different between the groups. CONCLUSION: Inducible NOS expression after extended hepatectomy is related to the effects of porto-systemic shunting on the splanchnic circulation. Also, iNOS induction and concomitant nitric oxide generation appear to participate in the cytotoxicity of excessive portal pressure after extended hepatectomy.

Role of Caenorhabditis elegans protein phosphatase type 1, CeGLC-7 beta, in metaphase to anaphase transition during embryonic development.

In Caenorhabditis elegans embryogenesis, phosphorylation events are critical to chromosomal changes. To investigate the dephosphorylation of chromosome behavior, we cloned and characterized the cDNA that encodes C. elegans protein phosphatase type 1 (CeGLC-7 beta), which is composed of 333 amino acids. CeGLC-7 beta possesses a highly conserved amino acid sequence with mammalian and Drosophila protein phosphatase 1. Here, we report on the contribution of CeGLC-7 beta to the dephosphorylation of histone H3 at anaphase. At the embryonic stage, CeGLC-7 beta is associated with the nuclear membrane and chromosomes. The deletion of the Ceglc-7 beta gene and a microinjection of double-stranded RNA produce a disorganized embryogenesis. The Ceglc-7 beta gene mutation causes an abnormal accumulation of phosphorylated histone H3 and delays the mitotic process after anaphase. We propose that CeGLC-7 beta is involved in chromosome dynamics including histone H3 dephosphorylation.

Expression of vascular endothelial growth factor D is associated with lymph node metastasis in human colorectal carcinoma.

OBJECTIVE: Expression of vascular endothelial growth factor (VEGF)-D by tumors is associated with metastasis to lymph nodes in mice. However, there are few reports concerning the clinical significance of VEGF-D protein in human carcinoma. METHODS: After confirming production of VEGF-D by eight colorectal carcinoma cell lines, we investigated relationships between the expression of VEGF-D protein, lymph node metastasis and postoperative survival in 83 colorectal carcinoma patients. mRNA levels in cell lines were evaluated using the real-time reverse transcriptase-polymerase chain reaction, and protein was detected by Western blotting in cell lines and by immunohistochemistry in resected tissues using an antibody recognizing the processed form of the molecule. RESULTS: Immunohistochemistry showed VEGF-D-positive staining in 26 of the 83 carcinomas (31%). There was a significant relationship between the presence of VEGF-D protein and the incidence of lymph node metastasis (p < 0.01). Multivariate logistic regression analysis revealed that VEGF-D protein expression was an independent factor affecting lymph node metastasis (p < 0.01). Nonetheless, the presence or absence of VEGF-D protein had no significant impact on the survival of the patients (p = 0.15). CONCLUSION: These results suggest that the expression of VEGF-D protein could be useful in predicting the nodal status of colorectal carcinoma patients.

Essential role for nuclear factor kappaB in ischemic preconditioning for ischemia-reperfusion injury of the mouse liver.

BACKGROUND: Ischemic preconditioning protects various organs from subsequent ischemic insult, but the precise mechanisms underlying this phenomenon remain undefined. To investigate the molecular mechanism by which ischemic preconditioning exerts its protective effect, we examined the activity of the transcription factor nuclear factor (NF)-kappaB and subsequent inflammatory gene expression. METHODS: Mice were used for total hepatic ischemia-reperfusion experiments after subcutaneous transposition of the spleen. Mouse liver was subjected to ischemia for 70 min followed by reperfusion for defined times. Ischemic preconditioning that consisted of 15 min of ischemia and 20 min of reperfusion was performed before 70 min of ischemia. NF-kappaB activity was analyzed by electrophoretic mobility shift assay, and the protein and tyrosine phosphorylation levels of inhibitor kappaB-alpha were assessed by Western blot analysis. Semiquantitative reverse-transcriptase polymerase chain reaction was used to analyze tumor necrosis factor (TNF)-alpha and intercellular adhesion molecule 1 mRNA levels. RESULTS: NF-kappaB was activated within 30 min after initiation of reperfusion and remained activated for 4 hr. Ischemic preconditioning attenuated NF-kappaB activation after subsequent prolonged ischemia and reperfusion and simultaneously decreased the expression of TNF-alpha and intercellular adhesion molecule 1 mRNA, the former statistically significantly (P <0.05). Tyrosine phosphorylation of inhibitor kappaB-alpha was decreased in ischemic preconditioned liver. CONCLUSIONS: These results indicate that attenuation of NF-kappaB activation and subsequent reduction in TNF-alpha mRNA expression after sustained ischemia play important roles in the protective mechanism of ischemic preconditioning against hepatic ischemia-reperfusion injury.

Extended longevity of Caenorhabditis elegans by knocking in extra copies of hsp70F, a homolog of mot-2 (mortalin)/mthsp70/Grp75.

The Caenorhabditis elegans homolog of mortalin/mthsp70/Grp75 (called mot-2 hereafter) was isolated by screening of a nematode cDNA library with mouse mot-2 cDNA. The isolated clone matched to hsp70F of C. elegans. Analysis with two of the antibodies raised against hsp70F revealed that unlike mammalian mot-2, it is heat inducible. Transient induction of hsp70F by heat shock led to a slight (<13%) extension in the C. elegans life span. The transgenic worms that constitutively over-expressed hsp70F predominantly in muscle showed life span extension (approximately 43% for mean and approximately 45% for maximum life span) as compared to the wild-type and green fluorescent protein-transgenic worms. Life span extension of human cells was obtained by over-expression of mot-2 [Kaul et al. (2000) FEBS Lett. 474, 159-164]. Our results show, for the first time, that this member of the hsp70 family governs the longevity of worms and thus there are common pathways that determine mammalian and worm longevity.