Exosomal microRNAs derived from colon cancer cells promote tumor progression by suppressing fibroblast TP53 expression.

The tumor microenvironment offers favorable conditions for tumor progression, and activated fibroblasts, known as cancer-associated fibroblasts, play a pivotal role. TP53-deficient cancer cells are known to induce strong fibroblast activation. We aimed to elucidate the oncogenic role of exosomes derived from TP53-deficient colon cancer cells in fibroblast proliferation and tumor growth. Cancer cell-derived exosomes (CDEs) were isolated from the conditioned media of cancer cells using a sequential ultracentrifugation method. The effects of exosomes on tumor growth were evaluated using human cell lines (TP53-WT colon cancer, HCT116; TP53-mutant colon cancer, HT29; and fibroblasts, CCD-18Co and WI-38) and an immune-deficient nude mouse xenograft model. HCT116 (HCT116sh p53 ) cells deficient in TP53 accelerated cocultured fibroblast proliferation compared to TP53-WT HCT116 (HCT116sh control ) cells in vitro. Exosomes from HCT116sh p53 cells suppressed TP53 expression of fibroblasts and promoted their proliferation. Xenografts of HCT116sh p53 cells grew significantly faster than those of HCT116sh control cells in the presence of co-injected fibroblasts, but this difference was diminished by CDE inhibition. Microarray analysis identified upregulation of several microRNAs (miR-1249-5p, miR-6737-5p, and miR-6819-5p) in TP53-deficient CDEs, which were functionally proven to suppress TP53 expression in fibroblasts. Exosomes derived from TP53-mutant HT29 cells also suppressed TP53 expression in fibroblasts and accelerated their growth. The proliferative effect of HT29 on cocultured fibroblasts was diminished by inhibition of these miRNAs in fibroblasts. Our results suggest that CDEs play a pivotal role in tumor progression by fibroblast modification. Cancer cell-derived exosomes might, therefore, represent a novel therapeutic target in colon cancer.

Adenoma of colorectal laterally spreading tumor nongranular type with biological phenotypic features similar to cancer.

BACKGROUND AND AIM: Colorectal laterally spreading tumors (LSTs) are morphologically subdivided into granular (LST-G) and nongranular (LST-NG) categories. We aimed to elucidate the differences in oncogenic characteristics between the two types. METHODS: Laterally spreading tumors resected by endoscopic submucosal dissection and surgery from March 2009 to May 2017 were examined for p53 positivity, Ki-67 labeling index (LI), microvessel density, degree of fibrosis, intensities of inducible nitric oxide synthase (iNOS) and nitrotyrosine (NT), and expression of acid mucins. We compared these factors between adenomas, noninvasive cancers, and invasive cancers, both LST-G and LST-NG. RESULTS: Ninety-three LST-G (53 adenomas [LST-GA] and 40 cancers [LST-GC]) and 55 LST-NG (24 adenomas [LST-NGA] and 31 cancers [LST-NGC]) were evaluated. Although p53 positivity was lower in LST-GA than in LST-NGA (P < 0.001), there was no difference between LST-GC and LST-NGC. Ki-67 LI was higher in LST-NGA than in LST-GA (P < 0.001) and higher in LST-NGC than in LST-GC of noninvasive cancers (P < 0.001). Microvessel density and degree of fibrosis were higher in LST-NGA than in LST-GA (P < 0.001), and intensities of iNOS and NT were also higher in LST-NGA than in LST-GA (P < 0.001). Expression of acid mucins was lower in LST-NGA than in LST-GA (P < 0.001). Although there were significant differences in p53 positivity, Ki-67 LI, microvessel density, degree of fibrosis, intensities of iNOS and NT, and expression of acid mucins between LST-GA and LST-NGA, these factors were only slightly different between LST-GC and LST-NGC of invasive cancers. CONCLUSIONS: Unlike LST-GA, LST-NGA possessed phenotypic features similar to cancer.

p53 functional deficiency in human colon cancer cells promotes fibroblast-mediated angiogenesis and tumor growth.

Cancer-associated fibroblasts (CAFs) create a microenvironment that contributes to tumor growth; however, the mechanism by which fibroblasts are phenotypically altered to CAFs remains unclear. Loss or mutation of the tumor suppressor p53 plays a crucial role in cancer progression. Herein, we analyzed how the p53 status of cancer cells affects fibroblasts by investigating the in vivo and in vitro effects of loss of p53 function in cancer cells on phenotypic changes in fibroblasts and subsequent tumor progression in human colon cancer cell lines containing wild-type p53 and in cells with a p53 functional deficiency. The growth of p53-deficient tumors was significantly enhanced in the presence of fibroblasts compared with that of p53-wild-type tumors or p53-deficient tumors without fibroblasts. p53-deficient cancer cells produced reactive oxygen species, which activated fibroblasts to mediate angiogenesis by secreting vascular endothelial growth factor (VEGF) both in vivo and in vitro Activated fibroblasts significantly contributed to tumor progression. Deletion of fibroblast-derived VEGF or treatment with N-acetylcysteine suppressed the growth of p53-deficient xenograft tumors. The growth effect of blocking VEGF secreted from cancer cells was equivalent regardless of p53 functional status. Human colon cancer tissues also showed a significant positive correlation between p53 cancer cell staining activated fibroblasts and microvessel density. These results reveal that fibroblasts were altered by exposure to p53-deficient epithelial cancer cells and contributed to tumor progression by promoting neovascularization. Thus, p53 acts as a modulator of the tumor microenvironment.

Integrated diagnostic strategy for the invasion depth of early gastric cancer by conventional endoscopy and EUS.

BACKGROUND: Although conventional endoscopy (CE) and EUS are considered useful for predicting the invasion depth (T-staging) in early gastric cancer (EGC), no effective diagnostic strategy has been established. OBJECTIVE: To produce simple CE criteria and to elucidate an efficient diagnostic method by combining CE and EUS for accurate T-staging. DESIGN: Single-center retrospective analysis. SETTING: Academic university hospital. PATIENTS: Consecutive patients with EGC from April 2007 to March 2012 who underwent CE and EUS before treatment. INTERVENTIONS: Recorded endoscopic images were independently reviewed by 3 observers. The CE criteria for massive invasion were defined, and their utility and the additional value of EUS were assessed. MAIN OUTCOME MEASUREMENTS: The accuracy of CE based on the criteria and the accuracy of EUS. RESULTS: Two hundred thirty patients were enrolled: 195 with mucosal cancer or cancer in the submucosa less than 500 µm from the muscularis mucosae and 35 with invasive cancers. Multivariate analysis of the CE findings by 1 observer revealed that an irregular surface and a submucosal tumor-like marginal elevation were significantly associated with massive invasion. The simple CE criteria, consisting of those 2 features, had an overall accuracy of 73% to 82% and no significant differences in the diagnostic yield compared with EUS in all observers. CE accurately revealed mucosal cancer, and EUS efficiently salvaged the lesions that were over-diagnosed by CE. With our strategy, which involved the CE criteria and the optimal use of EUS, the comprehensive accuracy exceeded 85% in each observer. LIMITATIONS: Retrospective, single-center study. CONCLUSIONS: We demonstrated a practical strategy for T-staging in EGC using simple CE criteria and EUS.

Adiponectin inhibits murine pancreatic cancer growth.

BACKGROUND: Adiponectin is an adipose tissue-derived secretory hormone whose plasma concentrations are lower in obese individuals. Obesity is a risk factor for the development and growth of pancreatic cancer, and hypoadiponectinemia was suggested to be involved in the growth of Pan02 murine pancreatic cancer cells that were inoculated into the flanks of congenitally obese mice. AIM: The aim of this study was to clarify the role of adiponectin in the growth of pancreatic cancer cells. METHODS: We examined the effect of adiponectin on the growth of Pan02 cells using recombinant adiponectin and adiponectin knockout mice. RESULTS: The in vitro treatment of Pan02 cells with adiponectin inhibited cellular proliferation that was accompanied by increased apoptosis and caspase-3 and caspase-7 activities. Transplantation of Pan02 cells into the pancreas of knockout mice resulted in a larger tumor volume with fewer terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) positive cells compared with wild-type mice. CONCLUSIONS: The results indicate that adiponectin directly suppresses the proliferation of Pan02 cells.

Adiponectin negatively correlates with alcoholic and non-alcoholic liver dysfunction: Health check-up study of Japanese men.

AIM: Central obesity, insulin resistance and alcohol consumption are thought to be major risk factors for fatty liver formation. Adiponectin (APN) prevents fatty liver formation, and its serum levels are lower in subjects with central obesity and/or insulin resistance. The aim of this study was to explore the association among serum APN levels, central obesity, insulin resistance and liver dysfunction with or without fatty liver classified by alcohol consumption in healthy subjects. METHODS: A total of 5588 Japanese male subjects who underwent a health check-up were classified into three groups according to alcohol consumption: non- or light drinkers (15 g/day ≥ ethanol); mild drinkers (15 g/day < ethanol ≤ 30 g/day); and moderate- or heavy drinkers (30 g/day < ethanol). Central obesity and insulin resistance were assessed by waist circumference (WC) and Homeostasis Model of Assessment - Insulin Resistance (HOMA-IR), respectively. RESULTS: WC was significantly increased, while HOMA-IR was significantly decreased according to the extent of alcohol consumption. Serum alanine aminotransferase levels were significantly lower and serum APN levels were significantly higher in mild drinkers than in the other two groups. Multiple linear regression analysis showed that serum APN level served as the significant and independent determinant for liver dysfunction in the subjects with fatty liver, irrespective of alcohol consumption. However, WC became a non-significant determinant of liver dysfunction as alcohol consumption increased. CONCLUSION: Hypoadiponectinemia is a significant determinant for steatotic dysfunction for all levels of alcohol consumption, but central obesity was not a significant determinant for alcoholic fatty liver-induced liver dysfunction.

Persistent Nausea and Gastrointestinal Distention: A Case Report of Aerophagia.

A 43-year-old woman experienced acute nausea, diarrhea, and abdominal pain, leading her to our hospital. No relevant medical history or physical abnormalities were noted. Symptoms persisted for a month, causing weight loss and abdominal bloating. CT scans revealed distension throughout the gastrointestinal tract without stenosis. Intestinal pseudo-obstruction and aerophagia were suspected. MR enterography confirmed normal gastric and intestinal motility, diagnosing the condition as aerophagia-induced gastrointestinal distention. This case underscores the value of MR enterography in assessing intestinal motility and differentiating between intestinal pseudo-obstruction and aerophagia.

Protective role of adiponectin against ethanol-induced gastric injury in mice.

Adiponectin is an anti-inflammatory molecule released from adipocytes, and serum adiponectin concentrations are reduced in obesity. We previously reported that gastric erosion occurs in association with obesity and low serum adiponectin levels. In the present study, we examined adiponectin-knockout (APN-KO) mice to elucidate the role of adiponectin in gastric mucosal injury. Gastric injury was induced by oral administration of ethanol in wild-type (WT) and APN-KO mice. Ethanol treatment induced severe gastric injury in APN-KO mice compared with WT mice. In APN-KO mice, increased apoptotic cells and decreased expression of prostaglandin E(2) (PGE(2)) were detected in the injured stomach. We next assessed the effect of adiponectin on the cellular response to ethanol treatment and wound repair in rat gastric mucosal cells (RGM1). Adiponectin induced the expression of PGE(2) and cyclooxygenase 2 (COX-2) in ethanol-treated RGM1 cells. RGM1 cells exhibited efficient wound repair accompanied by increased PGE(2) expression in the presence of adiponectin. Coadministration of adiponectin with celecoxib, a COX-2 inhibitor, inhibited efficient wound repair. These findings indicate that adiponectin has a protective role against ethanol-induced gastric mucosal injury in mice. This effect may be partially mediated by the efficient wound repair of epithelial cells via increased PGE(2) expression.

Is obesity a new risk factor for gastritis?

Obesity has become a major concern among gastroenterologists due to its large influence on gastrointestinal and hepatic diseases: reflux esophagitis, pancreatitis, gallstone disease, liver fibrosis, and neoplastic tumors of the esophagus, pancreas, and colon. Studies of morbid obese subjects undergoing bariatric surgery have revealed that obesity is related with an increased prevalence of endoscopic and histologic gastritis. A recent study of health check-up subjects demonstrated an association of obesity with endoscopic gastritis and gastric ulcers. We recently investigated the underlying mechanisms of the effects of obesity on endoscopic gastritis in subjects undergoing health check-up examination, and demonstrated that adiponectin, a bioactive molecule released from visceral fat, could be a protective factor of endoscopic gastritis. We would like to propose a new category of gastritis, obesity-related gastritis, which could become dominant in the near future.

Lower serum level of adiponectin is associated with increased risk of endoscopic erosive gastritis.

BACKGROUND: Obesity is recently known as a risk factor for endoscopic gastritis. Adiponectin is an anti-inflammatory cytokine secreted from fat tissue, and its serum concentrations are reduced in obesity. The relation between adiponectin and gastritis remains unclear. AIMS: The aim of this study was to determine whether lower serum adiponectin level is associated with the risk of endoscopic gastritis. METHODS: We analyzed medical records of participants of a routine health check-up examination. Association among endoscopic findings, serum adiponectin level, and other clinical factors including age, sex, alcohol habit, smoking habit, body mass index (BMI), blood pressure, cholesterol, triglyceride, glucose, and insulin were investigated. Endoscopic erosive gastritis was defined as a flat or minimally depressed white spot surrounded by a reddish area or small elevation with central umbilications mimicking octopus' suckers. RESULTS: A total of 2,400 participants were enrolled. BMI was significantly higher in gastritis-positive participants than in gastritis-negative participants. Serum adiponectin levels were significantly lower in gastritis-positive participants than in gastritis-negative participants. Multivariate logistic regression analysis revealed that lower serum adiponectin level (OR 0.96; 95% CI 0.93-0.99), smoking (OR 0.50; 95% CI 0.30-0.80), higher blood pressure (OR 1.02; 95% CI 1.01-1.03), and duodenitis (OR 1.8; 95% CI 1.00-3.09) were significantly associated with endoscopic erosive gastritis. CONCLUSIONS: Lower serum level of adiponectin may increase the risk of endoscopic erosive gastritis, independently of BMI. Our findings facilitate further study to clarify the role of hypoadiponectinemia in erosive gastritis.

[Bronchogenic cyst in the abdomen--a case report].

A man in his thirties with epigastric pain was referred to our hospital for detailed examinations. Abdominal computed tomography showed an abdominal cystic lesion with a longest dimension of 7 cm, located behind the stomach. Endoscopic ultrasonography through the stomach showed a cystic lesion and the wall of the lesion revealed continuity to the proper muscle layer of the gastric wall. Therefore, gastric duplication was suspected and the cystic lesion was resected because of the possibility of malignancy and also for a definitive diagnosis. The cystic lesion consisted of columnar ciliated epithelium, seromucous glands, smooth muscle and cartilage and was diagnosed as a bronchogenic cyst. Bronchogenic cysts are sometimes encountered in the thoracic or mediastinal area, but abdominal bronchogenic cysts, such as the present case, are extremely rare.

Lack of adiponectin promotes formation of cholesterol gallstones in mice.

Plasma adiponectin levels are reduced in obese people, and hypoadiponectinemia is recently reported to associate with cholesterol gallstone formation in human. The aim of this study was to examine the role of adiponectin in gallstone formation using adiponectin knockout mice. We analyzed male knockout and C57BL6J mice fed normal or lithogenic diet for 6 weeks. On lithogenic diet, the prevalence rate of gallstone was significantly greater in knockout mice than C57BL6J mice. The molar percentages of beta and omega-muricholic acid were significantly higher and hepatic sterol 12 alpha-hydroxylase expression (cyp8b1) was significantly lower in knockout mice than C57BL6J mice fed normal diet. The bile apolipoprotein A-I protein levels were decreased in knockout mice. Histological examination showed gallbladder wall thickening and accumulation of glycoprotein in the gallbladder of knockout mice. Gallbladder phospholipase A2-IVA expression was significantly higher in knockout mice than in C57BL6J mice fed lithogenic diet. Our results indicate that lack of adiponectin promotes gallstone formation in mice.

Restoration of gut motility in Kit-deficient mice by bone marrow transplantation.

PURPOSE: Interstitial cells of Cajal (ICC) play important roles in autonomic gut motility as electrical pacemakers and mediators of neural regulation of smooth muscle functions. Insufficiency of ICC has been reported in a wide range of gut dysmotilities. Thus, restoration of ICC may be a therapeutic modality in these diseases. Here we provide evidence that transplanted bone marrow (BM) cells can restore gut dysmotility in part via transdifferentiation to ICC. METHODS: Bone marrow cells obtained from Kit insufficient W/W(v) mice or syngeneic GFP-transgenic mice with wild-type Kit were transferred to W/W(v) recipients. Whole gut transit time and gastric emptying were examined 5 and 6 weeks after BM transplantation, respectively, and ICCs were identified in whole mounts, frozen sections and transmission electron immunomicroscopy of the gut smooth muscle layers using specific antibodies. RESULTS: Transplantation of wild-type BM into W/W(v) mice significantly improved whole gut transit time and gastric emptying. Fluorescent immunohistochemistry revealed GFP(+)Kit(+) cells in the myenteric plexus, deep muscular plexus, and submucosal plexus smooth muscle layers of the stomach, small intestine, and colon, respectively. In the whole mounts, GFP(+)Kit(+) cells were bipolar and spindle shaped, and transmission electron immunomicroscopy showed GFP(+) cells rich in mitochondria and endoplasmic reticulum between gut smooth muscle layers, suggesting the presence of GFP(+) cells with morphological characteristics of ICC. CONCLUSIONS: These results suggest that BM contains cells that may incorporate into ICC networks and improve dysmotility in W/W(v) mice. Thus, BM transplantation may become to a new therapeutic modality for gut dysmotilities due to ICC insufficiency.

Disturbed gastrointestinal motility and decreased interstitial cells of Cajal in diabetic db/db mice.

BACKGROUND AND AIM: Diabetes mellitus (DM) often causes gastrointestinal dysmotility. Interstitial cells of Cajal (ICC), which express c-kit receptor tyrosine kinase (KIT), are considered the pacemaker cells for gastrointestinal movement. The present study was designed to determine the role of ICC in the pathogenesis of gastroenteropathy in type 2 DM. METHODS: We examined C57BL/KsJ-db/db mice as a model for type 2 DM. Gastrointestinal motility was evaluated by measuring gastric emptying, whole gut transit time, and isometric tension of the isolated small intestine. The area of KIT-positive cells in the gastrointestinal tract was examined by image analysis of fluorescent immunohistochemistry. The mRNA expression of KIT ligand, stem cell factor (SCF), in the gastrointestinal tract was quantified by real-time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Compared with 12-week-old db/+m control mice, diabetic db/db mice of the same age exhibited delayed gastric emptying, prolonged whole gut transit time, irregular frequency of isometric tension in the small intestine, smaller areas of KIT-positive cells in the antrum, small intestine, and colon, and lower mRNA expression levels of SCF in the small intestine and colon. CONCLUSIONS: We demonstrated disturbed gastrointestinal motility in db/db mice with reduced areas of ICC and expression of SCF. Our results suggest the involvement of ICC in the gastroenteropathy of type 2 DM.

[18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) was useful tool for detecting tuberculous peritonitis: report of a case].

A 40's-year-old woman who had abdominal pain with fever was referred to our hospital for further examinations. Abdominal computed tomography showed no focal lesion, and no causative lesion was found after a gynecological examination, upper gastrointestinal endoscopy and colonoscopy. Tuberculin test and QuantiFERON-TB were positive, and thus tuberculous peritonitis was suspected. The level of adenosine deaminase (ADA) in ascites was high, and (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) showed that FDG accumulated diffusely along the peritoneum. These findings supported the findings of tuberculous peritonitis. Final diagnosis of tuberculous peritonitis was done from laparoscopic biopsy. Combination of QuantiFERON-TB, ADA and FDG-PET was useful in diagnosing tuberculous peritonitis.

Tissue Drug Concentrations of Anti-tumor Necrosis Factor Agents Are Associated with the Long-term Outcome of Patients with Crohn's Disease.

BACKGROUND: Many reports indicate that a high-serum trough level of anti-tumor necrosis factor (TNF) agents is required for sustained remission in patients with Crohn's disease The pharmacokinetics of anti-TNF agents in inflamed intestinal tissue, however, is not well investigated. We investigated the association between the tissue concentration of anti-TNF agents and long-term disease outcome. METHODS: This was a prospective single-center study that enrolled 25 patients with Crohn's disease who were administered infliximab or adalimumab. All participants underwent endoscopy 2 weeks after administration of the anti-TNF agents, and biopsy samples were obtained from both inflamed and noninflamed intestinal tissue. Tissue concentrations of anti-TNF agents were evaluated and the correlation with serum trough levels was compared. The relation between the tissue drug concentration and clinical course over 24 months was also investigated. RESULTS: Concentrations of anti-TNF agents were significantly higher in inflamed tissue than in noninflamed tissue. Patients with high-serum trough concentrations of anti-TNF agents had significantly higher drug levels in the noninflamed tissue than those with low-serum trough concentrations, but no difference in the levels was detected in the inflamed tissue. Patients with high-drug levels in the noninflamed tissue had a significantly higher sustained response rate than patients with low-drug levels. CONCLUSIONS: Concentrations of anti-TNF agents in the noninflamed tissue can reflect sustained remission and may be a useful biomarker for monitoring therapeutic intensity in patients with Crohn's disease treated with anti-TNF agents (see Video Abstract, Supplemental Digital Content 1, http://links.lww.com/IBD/B623).

Cloning of a soluble isoform of the SgIGSF adhesion molecule that binds the extracellular domain of the membrane-bound isoform.

SgIGSF (spermatogenic immunoglobulin superfamily) is a recently identified intercellular adhesion molecule of the immunoglobulin superfamily. In a mast-cell cDNA library, we found a clone that resulted from the retention of intron 7 within the mature SgIGSF message. This clone was predicted to encode a soluble isoform of SgIGSF (sSgIGSF) with 336 amino-acid residues because its open reading frame ended just before the transmembrane domain. We constructed a plasmid expressing sSgIGSF fused to the human IgG Fc fragment at its C-terminus (sSgIGSF-Fc), and transfected it into COS-7 cells. The fusion protein was readily detectable in the culture supernatant. Solid-phase binding assay showed that sSgIGSF interacted directly the extracellular domain of membrane-bound SgIGSF (mSgIGSF). We next examined whether this interaction inhibited homophilic binding of mSgIGSF by aggregation assays using L cells that did not express mSgIGSF. A stable L-cell clone that overexpressed mSgIGSF aggregated with each other but not with mock-transfected L cells, indicating that a homophilic interaction of mSgIGSF mediated the aggregation. Addition of sSgIGSF-Fc inhibited the aggregation of L cells overexpressing mSgIGSF in a dose-dependent manner. Moreover, FACScan analyses revealed the specific binding of sSgIGSF-Fc to mSgIGSF expressed in L cells. Binding of sSgIGSF-Fc to mSgIGSF appeared to inhibit homophilic interactions of mSgIGSF.

Gefitinib (Iressa, ZD1839) inhibits SN38-triggered EGF signals and IL-8 production in gastric cancer cells.

Epidermal growth factor receptor (EGFR) and its ligands are involved in tumor growth, metastasis, angiogenesis, and resistance to chemotherapy. In the experiments described here using AGS gastric cancer cells, SN38 (the active metabolite of CPT-11) induced tyrosine phosphorylation of EGFR within 5 min, and this was followed by the induction of transcripts and/or proteins of heparin-binding EGF-like growth factor, amphiregulin, transforming growth factor-alpha, and interlukin-8 (IL-8). SN38 also activates nuclear factor-kappaB and activator protein-1, both of which are critical for the transcription of the IL-8 gene. However, the blocking of EGFR activation by gefitinib (Iressa, ZD1839), an EGFR-TKI (tyrosine kinase inhibitor), abrogates all the above reactions. The SN38-triggered mechanisms include the generation of reactive oxygen species (ROS) and the activation of protein kinase C (PKC), followed by metalloproteinase activation and the sequential ectodomain shedding of EGFR ligands. These findings suggest that EGF signaling is enhanced by CPT-11 and point to the potential benefit of the use of a combination of CPT-11 with gefitinib in the treatment of certain gastric cancers.

Gefitinib ("Iressa", ZD1839) inhibits SN38-triggered EGF signals and IL-8 production in gastric cancer cells.

The epidermal growth factor receptor (EGFR) and its ligands are involved in tumor growth, metastasis, angiogenesis, and resistance to chemotherapy. The findings reported here demonstrate that SN38 (the active metabolite of CPT-11) induces the tyrosine phosphorylation of EGFR within 5 min, followed by the induction of transcripts and/or proteins of the heparin-binding EGF-like growth factor, amphiregulin, transforming growth factor-alpha, and interlukin-8 (IL-8) in AGS gastric cancer cells. SN38 also activates nuclear factor-kappa B and activator protein-1, both of which are critical for the transcription of the IL-8 gene. However, the blocking of EGFR activation by gefitinib ("Iressa", ZD1839), an EGFR-TKI (tyrosine kinase inhibitor), abrogates all the above reactions. The SN38-triggered mechanisms include the generation of reactive oxygen species (ROS) and the activation of protein kinase C (PKC), followed by metalloproteinase activation and the sequential ectodomain shedding of EGFR ligands. These findings suggest that EGF signaling is enhanced by CPT-11 and point to the potential benefit of the use of a combination of CPT-11 with gefitinib in the treatment of certain gastric cancers.

[A case of new-onset refractory status epilepticus (NORSE) with an autoimmune etiology].

A 23-year-old man presented tonic-clonic seizure a week after an episode of antecedent infection. Although several anticonvulsants were used, convulsive attacks were not resolved and intravenous anesthetics were used to stop status epileptics. After combination of immunotherapies (high-dose intravenous methylprednisolone, immune absorbance and intravenous immunoglobulin (IVIg) therapies), frequency of convulsive attacks decreased, however, disturbance of consciousness was not recovered. All anti-neuronal antibodies tested were negative. Indirect immunofluorescence using the serum and rat brain section revealed positive signals in cytoplasm and nucleus in hippocampal neurons, strongly suggesting that this case has an autoimmune pathogenesis. The clinical features and course of this patient are well consistent with those in new-onset refractory status epilepticus (NORSE). The result of immunohistochemical analysis supports the hypothesis that NORSE has an autoimmune pathomechanism.