Toshinaga Nabae

MicroRNA-21 modulates biological functions of pancreatic cancer cells including their proliferation, invasion, and chemoresistance.

Due to the poor prognosis of pancreatic cancer, novel diagnostic modalities for early diagnosis and new therapeutic strategy are urgently needed. Recently, microRNA-21 (miR-21) was reported to be strongly overexpressed in pancreatic cancer as well as in other solid cancers. We investigated the functional roles of miR-21, which have not been fully elucidated in pancreatic cancer. miR-21 expression was assessed in pancreatic cancer cell lines (14 cancer cell lines, primary cultures of normal pancreatic epithelial cells and fibroblasts, and a human normal pancreatic ductal epithelial cell line) and pancreatic tissue samples (25 cancer tissues and 25 normal tissues) by quantitative real-time reverse transcription-PCR amplification. Moreover, we investigated the proliferation, invasion, and chemoresistance of pancreatic cancer cells transfected with miR-21 precursor or inhibitor. miR-21 was markedly overexpressed in pancreatic cancer cells compared with nonmalignant cells, and miR-21 in cancer tissues was much higher than in nonmalignant tissues. The cancer cells transfected with the miR-21 precursor showed significantly increased proliferation, Matrigel invasion, and chemoresistance for gemcitabine compared with the control cells. In contrast, inhibition of miR-21 decreased proliferation, Matrigel invasion, and chemoresistance for gemcitabine. Moreover, miR-21 positively correlated with the mRNA expression of invasion-related genes, matrix metalloproteinase-2 and -9, and vascular endothelial growth factor. These data suggest that miR-21 expression is increased in pancreatic cancer cells and that miR-21 contributes to the cell proliferation, invasion, and chemoresistance of pancreatic cancer.[Mol Cancer Ther 2009;8(5):1067–74]

Severe Localized Stenosis and Marked Dilatation of the Main Pancreatic Duct are Indicators of Pancreatic Cancer Instead of Chronic Pancreatitis on Endoscopic Retrograde Balloon Pancreatography

BACKGROUND Differentiation between benign and malignant localized stenoses of the main pancreatic duct is difficult by pancreatography. METHODS A total of 48 patients with such localized stenosis who underwent endoscopic retrograde balloon pancreatography with abdominal compression were retrospectively studied. The following were examined: (1) diameter of the stenotic, prestenotic, and poststenotic ductal segments; (2) ratios of prestenotic/poststenotic, stenotic/prestenotic, and stenotic/poststenotic ductal segments; (3) length of stenosis and steepness of transition to the stenosis (proximal angle, distal angle); and (4) main duct and branch findings for peristenotic segments. RESULTS The stenosis was diagnosed as caused by chronic pancreatitis in 27 patients and pancreatic cancer in 21 by histopathology, cytology, or clinical follow-up. The prestenotic/poststenotic ductal segments ratio and proximal angle were greater in pancreatic cancer compared with chronic pancreatitis. Severe stenosis (stenotic ductal segments less than 20% of prestenotic or poststenotic ductal segments); moderate (prestenotic ductal segments 2.5 to 3.5 times larger than poststenotic ductal segments), and severe (prestenotic ductal segments more than 3.5 times larger than poststenotic ductal segments) dilatation of the proximal duct were more frequent in pancreatic cancer than in chronic pancreatitis. Multivariate regression analyses showed that severe stenosis and dilatation were independently significant parameters that indicated a diagnosis of pancreatic cancer. Various combinations of severe stenosis, proximal dilatation, and double duct sign gave high predictive values. CONCLUSIONS Severe stenosis, marked proximal dilatation, double duct sign, and combinations of these findings are useful indicators of malignant localized stenosis of the pancreatic duct.

Adenosquamous carcinoma of the pancreas: report of two cases.

Adenosquamous carcinoma of the pancreas is a rare variant of pancreatic exocrine carcinoma. We herein report two patients with this entity. One patient was a 60-yr-old Japanese man complaining of a palpable mass, 5.5 cm in the greatest diameter, in the epigastrium. Serum CA 19–9 was increased (2010 U/ml). Ultrasonography and computed tomography showed a mass in the pancreatic tail with central necrosis and invading the posterior wall of the stomach. Angiography showed an encasement of the splenic artery and complete obstruction of the splenic vein. Distal pancreatectomy, splenectomy, and partial resection of the stomach were done. The patient died of uncontrolled bleeding from the duodenal ulcer four months after operation. The other patient was a 73-yr-old man who presented with jaundice. The CA 19–9 was also elevated (354.8 U/ml). Ultrasonography showed a pancreatic head mass of heterogeneous echogeneity and computed tomography demonstrated a cystic mass with an enhanced rim, indicating necrosis in the tumor center. Angiography showed a hypervascular mass in the head of the pancreas. Pylorus-preserving pancreatoduodenectomy was done, but the patient died of multiple liver metastases 10 months after the operation. From our experience with the two patients, the presence of central necrosis in an infiltrative huge pancreatic tumor seems to be suggestive of the diagnosis of adenosquamous carcinoma of the pancreas.

Establishment of a new human pancreatic cancer cell line, NOR-P1, with high angiogenic activity and metastatic potential

We present here a new cell line, NOR-P1, established from a metastatic subcutaneous tumor of a patient with pancreatic cancer. The cells show rapid growth in culture with a doubling time of 16 h and high migration activity. Genetic and molecular analyses revealed high telomerase activity and a mutation in the K-ras oncogene. Of particular interest, the cells express markedly elevated mRNA levels of angiogenic factors, vascular endothelial growth factor and platelet-derived growth factor, as well as other tumor growth-related factors. Subcutaneous transplantation of the NOR-P1 cells into nude mice formed solid, hemorrhagic tumors which were histologically diagnosed as adenocarcinoma with dense blood vessels and severe extravasation of blood. Furthermore, when NOR-P1 cell suspension was injected directly into the pancreas of nude mice, the cells grew rapidly to form intra-pancreatic tumors associated with liver metastases and peritoneal dissemination that resulted in cachexia and subsequent death. These properties suggest that NOR-P1 is an aggressive pancreatic cancer cell line with a high metastatic potential and may serve as a useful experimental model for studying tumor angiogenesis and metastasis of pancreatic cancer.

Prospectively Isolated Cancer-Associated CD10+ Fibroblasts Have Stronger Interactions with CD133+ Colon Cancer Cells than with CD133− Cancer Cells

Although CD133 has been reported to be a promising colon cancer stem cell marker, the biological functions of CD133+ colon cancer cells remain controversial. In the present study, we investigated the biological differences between CD133+ and CD133− colon cancer cells, with a particular focus on their interactions with cancer-associated fibroblasts, especially CD10+ fibroblasts. We used 19 primary colon cancer tissues, 30 primary cultures of fibroblasts derived from colon cancer tissues and 6 colon cancer cell lines. We isolated CD133+ and CD133− subpopulations from the colon cancer tissues and cultured cells. In vitro analyses revealed that the two populations showed similar biological behaviors in their proliferation and chemosensitivity. In vivo analyses revealed that CD133+ cells showed significantly greater tumor growth than CD133− cells (P = 0.007). Moreover, in cocultures with primary fibroblasts derived from colon cancer tissues, CD133+ cells exhibited significantly more invasive behaviors than CD133− cells (P<0.001), especially in cocultures with CD10+ fibroblasts (P<0.0001). Further in vivo analyses revealed that CD10+ fibroblasts enhanced the tumor growth of CD133+ cells significantly more than CD10− fibroblasts (P<0.05). These data demonstrate that the in vitro invasive properties and in vivo tumor growth of CD133+ colon cancer cells are enhanced in the presence of specific cancer-associated fibroblasts, CD10+ fibroblasts, suggesting that the interactions between these specific cell populations have important roles in cancer progression. Therefore, these specific interactions may be promising targets for new colon cancer therapies.

Comparison of recovery of gastric phase III motility and gastric juice output after different types of gastrointestinal reconstruction following pylorus-preserving pancreatoduodenectomy

Background:Background: Early gastric stasis is a frequent complication of pylorus-preserving pancreatoduodenectomy (PPPD). However, few reports have addressed this phenomenon in relation to the type of gastrointestinal reconstruction. We compared gastrointestinal motility and gastric juice output after two different types of gastrointestinal reconstruction following PPPD, end-to-side duodenojejunostomy after pancreaticojejunostomy and hepaticojejunostomy (group 1) and end-to-end duodenojejunostomy before pancreaticojejunostomy and hepaticojejunostomy (group 2). Method: In a total of 25 patients, 10 in group 1 and 15 in group 2, who underwent PPPD, manometry was repeated to assess gastric and jejunal motility until the first occurrence of phase III activity of gastric cyclic motor activity (CMA). The plasma level of motilin was measured in each phase of the gastric CMA and compared between the two groups. The daily volume of gastric juice output through a gastrostomy tube was also recorded for comparison. Result: There was no significant difference in the time period for recovery of gastric phase III activity and gastric juice output between the two groups. However, abnormal contractions with an increased basal pressure appeared frequently in the afferent jejunal loop only in group 1. The plasma motilin level after PPPD showed no apparent cyclic change even after the recovery of gastric phase III in either group. Conclusion: Gastrointestinal reconstructive procedures have almost no effect on the recovery of gastric CMA. The plasma motilin concentration does not play a major role in the recovery of gastric CMA in the early postoperative period after PPPD.

Effects of Proximal Duodenal Transection and Anastomosis on Interdigestive Sphincter of Oddi Cyclic Motility in Conscious Dogs

Abstract. Gallstones formed after gastrectomy are bilirubinate stones probably associated with biliary stasis and infection. Effects of proximal duodenal transection performed during gastrectomy on interdigestive sphincter of Oddi cyclic motility possibly relevant to this phenomenon were investigated in four conscious dogs. Although the cyclic change in sphincter motility was still in concert with the duodenal migrating motor complex after duodenal transection, the mean period was shortened (p < 0.02), and the frequency (p < 0.005) and amplitude (p < 0.001) of sphincter phasic waves during phase III were decreased. The cyclic variation of basal pressure disappeared, and the mean basal pressure throughout the cycle was significantly reduced (p < 0.003). Transient inhibition of sphincter and duodenal contractions normally seen during phase III disappeared. Duodenal transection reversed the response of the sphincter to cholecystokinin-octapeptide from inhibition to stimulation and from reduction of the basal pressure to elevation. These data suggest that duodenal transection produces significant changes in interdigestive sphincter of Oddi motility, possibly contributing to augmented duodenobiliary reflux and then lithogenesis. Myoneural continuity between the stomach and sphincter of Oddi at the proximal duodenum may play an important role in maintaining normal biliary dynamics.

Effect of truncal vagotomy on sphincter of Oddi cyclic motility in conscious dogs

ObjectiveTo evaluate the effects of truncal vagotomy at the diaphragmatic level on the sphincter of Oddi (SO) motility. Summary Background DataCholelithiasis is a well-known late complication after gastrectomy and/or vagotomy. The mechanism of gallstone formation is only partly understood, and few studies address the effects of vagotomy on SO cyclic motility in conscious subjects. MethodsIn conscious dogs, SO motility was recorded by retrograde infusion manometry through a duodenal cannula before and after bilateral truncal vagotomy at the diaphragmatic level. Effects of cholecystokinin-octapeptide and feeding were also evaluated before and after vagotomy. ResultsSO cyclic motility and the gastroduodenal migrating motor complex continued to occur during postvagotomy fasting. Intermittent inhibitions of the SO and duodenal contractions disappeared during phase 3 of the migrating motor complex. SO basal pressure significantly decreased, whereas the amplitude significantly increased. Cholecystokinin-octapeptide inhibited SO contractions before and after vagotomy. The amplitude of SO contractions increased and their frequency decreased after feeding; however, these effects disappeared after vagotomy. ConclusionsSO cyclic motility and the effects of feeding change after truncal vagotomy at the diaphragmatic level. These facts may at least partly explain gallstone formation after gastric surgery and/or vagotomy.

Pain associated with phase III of the duodenal migrating motor complex in patients with postcholecystectomy biliary dyskinesia

BACKGROUND Correlation between various gastrointestinal events and particular aspects of the migrating motor complex has been reported. This study correlates postcholecystectomy pain to variations in biliary pressure associated with the duodenal motor cycle. METHODS In 18 patients with postcholecystectomy pain and 10 control subjects, biliary and duodenal pressures were recorded simultaneously with microtransducers. After recording a spontaneous cycle, morphine was administered to induce a premature phase III and spasm of the sphincter of Oddi, and then cerulein was administered to stop the spasm. RESULTS Transient but significant elevations of biliary pressure occurred at duodenal phase III in both groups, but a greater percentage of the patients developed pain during phase III (89% vs. 20%, p<0.01). Morphine produced premature phase III and biliary pressure elevation, which were accompanied by pain more frequently in the patients than in the control subjects (78% vs. 30%, p<0.05). Biliary pressure dropped after the cerulein injection, relieving the pain in 13 of 14 patients and in 2 of 3 control subjects who had morphine-induced pain. The phase III-related pain was relieved by endoscopic sphincterotomy in 14 of 15 patients. CONCLUSIONS The cyclic elevation of biliary pressure in coordination with phase III of the duodenal motor cycle may contribute to the development of pain in patients with postcholecystectomy biliary dyskinesia.

Effect of prepyloric gastric transection and anastomosis on sphincter of Oddi cyclic motility in conscious dogs.

Purpose. We previously reported significant changes in sphincter of Oddi cyclic motility after proximal duodenal transection and anastomosis. However, the role of intrinsic myoneural continuity between the antrum and duodenum in this respect is not understood. The aim of this study was to elucidate the effects of prepyloric gastric transection on sphincter of Oddi motility in animals in the conscious state. Methods. Pressures in the bile duct, duodenum, stomach, and sphincter of Oddi and their response to an injection of cholecystokinin-octapeptide were measured in four conscious dogs, with a duodenal cannula, before and after gastric transection and anastomosis 1.5 cm proximal to the pylorus. Results. Gastric transection did not affect the initiation and propagation of the gastroduodenal migration motor complex. Biliary pressure (5.7 ± 0.15 to 5.5 ± 0.2 mmHg; P = 0.91), sphincter of Oddi basal pressure (10.6 ± 0.3 to 10.7 ± 0.2 mmHg; P = 0.97), and amplitude (26.0 ± 1.2 to 32.9 ± 1.7 mmHg; P = 0.304) did not change after gastric transection. Biliary pressure decreased from phase II to phase III of the duodenal migrating motor complex. Cholecystokinin-octapeptide inhibited sphincter of Oddi phasic waves before and after gastric transection. Conclusions. Intrinsic myoneural transection at the prepyloric region does not influence sphincter of Oddi cyclic motility. Preservation of pyloroduodenal myoneural continuity in pylorus-preserving gastrectomy would be beneficial to maintain normal sphincter of Oddi motility.