Establishment of a novel method to evaluate peritoneal microdissemination and therapeutic effect using luciferase assay.

Peritoneal dissemination is a major cause of recurrence in patients with malignant tumors in the peritoneal cavity. Effective anticancer agents and treatment protocols are necessary to improve outcomes in these patients. However, previous studies using mouse models of peritoneal dissemination have not detected any drug effect against peritoneal micrometastasis. Here we used the luciferase assay to evaluate peritoneal micrometastasis in living animals and established an accurate mouse model of early peritoneal microdissemination to evaluate tumorigenesis and drug efficacy. There was a positive correlation between luminescence intensity in in vivo luciferase assay and the extent of tumor dissemination evaluated by ex vivo luciferase assay and mesenteric weight. This model has advantages over previous models because optimal luciferin concentration without cell damage was validated and peritoneal microdissemination could be quantitatively evaluated. Therefore, it is a useful model to validate peritoneal micrometastasis formation and to evaluate drug efficacy without killing mice.

MicroRNA-7 expression in colorectal cancer is associated with poor prognosis and regulates cetuximab sensitivity via EGFR regulation.

MicroRNA-7 (miR-7) has been reported to be a tumor suppressor in all malignancies including colorectal cancer (CRC). However, its significance for CRC clinical outcomes has not yet been explored. The potential for miR-7 to act as a tumor suppressor by coordinately regulating the epidermal growth factor receptor (EGFR) signaling pathway at several levels was examined. We investigated the tumor inhibitory effect of miR-7 in CRC, with particular focus on the relationship between miR-7 and the EGFR pathway. Quantitative reverse transcription-PCR was used to evaluate miR-7 expression in 105 CRC cases to determine the clinicopathologic significance of this miRNA. The regulation of EGFR by miR-7 was examined with miR-7 precursor-transfected cells. Furthermore, we investigated whether miR-7 suppresses proliferation of CRC cells in combination with cetuximab, a monoclonal antibody against EGFR. Multivariate analysis indicated that low miR-7 expression was an independent prognostic factor for poor survival (P = 0.0430). In vitro assays showed that EGFR and RAF-1 are direct targets of miR-7, which potently suppressed the proliferation of CRC cells, and, interestingly, that the growth inhibitory effect of each of these was enhanced by cetuximab. miR-7 is a meaningful prognostic marker. Furthermore, these data indicate that miR-7 precursor, alone or in combination with cetuximab, may be useful in therapy against CRC.

Effects of 5-HT2B, 5-HT3 and 5-HT4 receptor antagonists on gastrointestinal motor activity in dogs.

AIM: To study the effects of 5-hydroxytryptamine (5-HT) receptor antagonists on normal colonic motor activity in conscious dogs. METHODS: Colonic motor activity was recorded using a strain gauge force transducer in 5 dogs before and after 5-HT2B, 5-HT3 and 5-HT4 receptor antagonist administration. The force transducers were implanted on the serosal surfaces of the gastric antrum, terminal ileum, ileocecal sphincter and colon. Test materials or vehicle alone was administered as an intravenous bolus injection during a quiescent period of the whole colon in the interdigestive state. The effects of these receptor antagonists on normal gastrointestinal motor activity were analyzed. RESULTS: 5-HT2B, 5-HT3 and 5-HT4 receptor antagonists had no contractile effect on the fasting canine terminal ileum. The 5-HT3 and 5-HT4 receptor antagonists inhibited phase III of the interdigestive motor complex of the antrum and significantly inhibited colonic motor activity. In the proximal colon, the inhibitory effect was dose dependent. Dose dependency, however, was not observed in the distal colon. The 5-HT2B receptor antagonist had no contractile effect on normal colonic motor activity. CONCLUSION: The 5-HT3 and 5-HT4 receptor antagonists inhibited normal colonic motor activity. The 5-HT2B receptor antagonist had no contractile effect on normal colonic motor activity.

Galectin-3, a novel binding partner of beta-catenin.

Galectin-3 (gal-3), a pleiotrophic protein, is an important regulator of tumor metastasis, which like beta-catenin shuttles between the nucleus and the cytosol in a phosphorylation-dependent manner. We report herein that beta-catenin stimulation of cyclin D1 and c-myc expression is gal-3 dependent. Gal-3 binds to beta-catenin/Tcf complex, colocalizes with beta-catenin in the nucleus, and induces the transcriptional activity of Tcf-4 as determined by the TOP/FOPFLASH reporter system. We have identified the beta-catenin-gal-3-binding sequences, which are in the NH2 and COOH termini of the proteins encompassing amino acid residues 1 to 131 and 143 to 250, respectively. These data indicate that gal-3 is a novel binding partner for beta-catenin involved in the regulation of Wnt/beta-catenin signaling pathway.

Double endoscopic intraluminal operation for upper digestive tract diseases: proposal of a novel procedure.

BACKGROUND AND OBJECTIVE: Endoscopic treatment of digestive tract diseases, such as early esophageal and gastric neoplasia, has become increasingly popular in recent years as an alternative to surgical procedures in the hope of providing an improved quality of life for these patients. However, one of the limitations of a conventional endoscopic mucosal resection, such as an aspiration mucosectomy and a strip biopsy, has been the size of the lesions to be resected. Both an aspiration mucosectomy and strip biopsy are useful variants for removing flat lesions measuring less than 20 mm in maximal diameter. To overcome such limitations, we devised a double endoscopic intraluminal operation (DEILO), which enables us to resect mucosal lesions by using 2 fine endoscopes and monopolar shears. METHODS: DEILO was performed on patients with esophageal and gastric lesions measuring up to 40 mm in diameter. This novel technique is characterized by the use of 2 endoscopes (one for lifting the lesion and the other for cutting the lesions) inserted into the esophagus or stomach through an overtube. A mucosal resection is then performed by dissecting the mucosal margin with newly developed monopolar shears, thereby separating the mucosa from the submucosa. RESULTS: A total of 25 lesions in the esophagus (8 lesions) and stomach (17 lesions) were resected by DEILO. The sizes of the esophageal lesions ranged from 8 to 40 mm in diameter (mean, 21.1 mm) whereas gastric lesions ranged from 8 to 30 mm (mean, 13.3 mm) in diameter, and histopathologic examinations revealed the resection margin to be clear and without any tumor. No complications or instances of recurrence were observed in this series. CONCLUSIONS: DEILO is considered to be feasible for the mucosal resection of esophageal and gastric lesions measuring more than 10 mm in diameter without submucosal invasion, whereas conventional endoscopic mucosal resection is indicated for such lesions measuring less than 10 mm in size.

Left hepatectomy for the choledochal cyst (type IV-A) with intrahepatic stenosis: report of a case.

The case of a 16-year-old male with expansion of the gallbladder and dilatation of the common bile duct is reported. Ultrasonography and computed tomography imaging showed expansion of the gallbladder and eminent cystic dilatation in the common bile duct and the left intrahepatic bile duct. Endoscopic retrograde cholangiopancreatography indicated expansion-like beads of the bilateral hepatic ductus and the left intrahepatic bile duct, including anomalies of the pancreaticobiliary ductal junction. Because relative stenosis of the membranous diaphragm was revealed in the porta hepatis, we diagnosed this case as a type IV-A choledochal cyst, using Todani's classification. Intraoperative cholangiography and cholangiofiberscopy showed a pinhole stricture and re-expansion of the tip of the left intrahepatic bile duct. As the narrow segment could not be expanded though we put proper pressure there, left hepatectomy was performed as a preventive measure in addition to extended biliary tract excision and cholangiojejunostomy. Hepatectomy seems to be an appropriate choice in a case of intrahepatic stenosis to help increase the patient's postoperative quality of life.