Usefulness of transanal tube placement for prevention of anastomotic leakage following laparoscopic low anterior resection

INTRODUCTION

Anastomotic leakage (AL) is a major complication of laparoscopic low anterior resection (LLAR) for rectal cancer. Although several recent reports have suggested that transanal tube placement can prevent AL, this practice is still controversial. Additionally, the mechanism by which a transanal tube prevents AL is unknown. The aim of this study was to evaluate the efficacy of transanal tube placement for prevention of AL following LLAR.

METHODS

This was a retrospective study that included 69 patients who underwent LLAR between February 2012 and January 2016. After an anastomosis using a double stapling technique, a transanal tube was placed in 28 patients. A diverting stoma was created in 26 patients. Univariate and multivariate analyses of clinicopathological characteristics were performed.

RESULTS

The overall incidence of AL was 15.9% (11/69). Univariate analysis showed that transanal tube placement (P = 0.022) and early postoperative diarrhea (P < 0.001) were associated with AL. The duration of the postoperative hospital stay for patients with transanal tube placement (13.1 ± 4.1 days) was significantly shorter than for patients without a transanal tube (22.7 ± 12.3 days; P < 0.001). However, transanal tube placement did not reduce postoperative diarrhea. Creation of a diverting stoma did not affect the incidence of AL. Multivariate analysis revealed that the absence of a transanal tube (odds ratio = 33.5, P = 0.018) and the occurrence of postoperative diarrhea (odds ratio = 86.3, P = 0.001) were independent risk factors for AL.

CONCLUSION

Transanal tube placement prevents AL after LLAR. Furthermore, this protective effect may be due to a reduction in the unfavorable incidence of early postoperative diarrhea.

High-voltage capabilities of ultra-thin Nb2O5 nanosheet coated LiNi1/3Co1/3Mn1/3O2 cathodes

The surface coating of LiNi_1/3Co_1/3Mn_1/3 electrode with 1.1 nm Nb₂O₅ nanosheet enhanced the high voltage capability and long term stability of the charged state at 60 °C by reducing the contact area between electrode and electrolyte.

A case of primary adenocarcinoma of the third portion of the duodenum resected by laparoscopic and endoscopic cooperating surgery

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Laparoscopic and endoscopic cooperating surgery (LECS) enabled en bloc resection with adequate surgical margins and secure intra-abdominal suturing for duodenal neoplasms.

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Thorough mobilization of the mesocolon and pancreas head is essential for this procedure because it facilitates correct resection and suturing.

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LECS is a feasible treatment option for duodenal neoplasms.

Introduction

We report a case of primary adenocarcinoma in the third portion of the duodenum (D3) curatively resected by laparoscopic and endoscopic cooperating surgery (LECS).

Presentation of case

A 65-year-old woman had a routine visit to our hospital for a follow-up of rectal cancer resected curatively 2 years ago. A routine screening gastroduodenal endoscopy revealed an elevated lesion of 20 mm in diameter in the D3. The preoperative diagnosis was adenoma with high-grade dysplasia; however, suspicion about potential adenocarcinoma was undeniable. Curative resection was performed by LECS. Pathological examination revealed intramucosal adenocarcinoma arising from normal duodenal mucosa. The tumor was stage I (T1/N0/M0) in terms of the tumor, nodes, metastasis (TNM) classification. LECS for duodenal tumor has seldom been reported previously, and this is the first report of LECS for primary adenocarcinoma in the D3. The transverse mesocolon was removed from the head of pancreas to expose the duodenum, and the accessory right colic vein was cut; this was followed by the Kocher maneuver for mobilization of the lesion site.

Discussion

LECS enabled en bloc resection with adequate surgical margins and secure intra-abdominal suturing. Thorough mobilization of the mesocolon and pancreas head is essential for this procedure because it facilitates correct resection and suturing.

Conclusion

LECS is a feasible treatment option for duodenal neoplasms, including intramucosal adenocarcinoma, even though it exists in the D3.

Catheter-directed thrombolysis through the operatively recanalized umbilical vein for acute extensive portal vein thrombosis: report of a case

Acute portal vein thrombosis is a rare but severe complication of intra-abdominal infection. It can be life-threatening, given the risk of developing liver abscess and subsequent liver failure. Various types of hereditary thrombophilia are known risk factors for acute portal vein thrombosis. In addition to surgical treatment and potent antibiotic therapy, systemic administration of anticoagulants and locoregional trans-catheter delivery of thrombolytic agents are known to be effective. We present a case report of acute portal vein thrombosis with pylephlebitis caused by acute appendicitis, successfully treated with catheter-directed thrombolysis through the operatively recanalized umbilical vein. The umbilical vein is a promising access route to the portal vein. Therefore, this procedure is an effective and preferred treatment option for portal septic thrombosis, particularly because it does not require puncture of the liver parenchyma or catheterization through an infected peritoneal cavity.

Successful neoadjuvant treatment with radiochemotherapy and systemic chemotherapy for the locally advanced pancreatic head cancer: report of a case

A 49-year-old man was admitted to the hospital for the upper abdominal pain and was diagnosed as unresectable pancreatic head cancer because of the invasion around the superior mesenteric artery. He was treated with radiochemotherapy, followed by systemic gemcitabine alone for 3 courses. He was further treated with systemic gemcitabine plus S‑1 combination therapy for 5 courses. CT examination after these treatments showed a dramatic reduction of the tumor at the head of the pancreas and a pancreatoduodenectomy was performed. Pathologically, there was no residual malignant tumor. He has had no recurrent tumor up until now. Several studies of gemcitabine plus S-1 combination therapy show higher response rates for unresectable tumors. The current case indicates the effectiveness of the radiochemotherapy and gemcitabine plus S‑1 combination therapy for locally advanced pancreatic head cancer as a neoadjuvant setting. We consider that multidisciplinary treatment including gemcitabine plus S‑1 therapy may prolong the survival time by curative operation.

Diagnostic value of (18)F-fluorodeoxyglucose positron emission tomography for pancreatic neuroendocrine tumors with reference to the World Health Organization classification

The 2004 classification of the World Health Organization (WHO) has demonstrated an efficacy for prediction of the prognosis of pancreatic neuroendocrine tumors. This study aimed to assess the predictive value of preoperative (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in relation to the 2004 WHO criteria. The histology of 21 pancreatic endocrine tumors resected at our hospital was reviewed and the tumors were classified according to the 2004 WHO criteria. FDG-PET findings were analyzed by comparing the findings with CT scans. FDG uptake was positive in 10 primary endocrine tumors (47%), but no uptake was seen in 11 tumors. In relation to the 2004 WHO classification, 1 out of 8 well-differentiated tumors with benign behavior was positive by PET (12.5%), 4 out of 7 well-differentiated tumors with uncertain behavior were positive (57%) and 4 low-grade malignant tumors were positive (100%). According to the WHO criteria, the rate of positive FDG uptake increased as the malignant potential increased. The metastases of low-grade malignant tumors also showed a positive FDG uptake. In conclusion, from our limited experience, FDG-PET appears to be useful for identifying pancreatic neuroendocrine tumors with a higher malignant potential. In addition, FDG-PET can detect distant metastases and may contribute to better staging of advanced disease.

Adenovirus vectors with chimeric type 5 and 35 fiber proteins exhibit enhanced transfection of human pancreatic cancer cells

Adenovirus (Ad) vectors are widely used for gene transfer. Efficient gene transfer into malignant cells is an important requirement for anticancer gene therapy, but transgene expression after transfer with adenoviral vectors varies among different cancer cell lines. Recently, Ad vectors containing chimeric type 5 and 35 fiber proteins have been developed. We evaluated the expression of coxsackie and adenovirus receptor (CAR), as well as integrins alphaV, beta3 and beta5, in seven human pancreatic cancer cell lines and assessed the relationship between expression of these molecules and Ad transfection efficiency. We compared the transfection efficiency of a conventional type 5 Ad vector (Ad5GFP) with that of an Ad vector containing chimeric type 5 and 35 fiber proteins (Ad5/35GFP), which expressed green fluorescent protein (GFP) driven by the cytomegalovirus promoter. There was strong CAR expression by AsPC-1, CFPAC-1 and PANC-1 cells, whereas the other cell lines showed weak expression. There was strong integrin beta3 expression by MIAPaCa-2, PANC-1 and Suit-2 cells, but expression by AsPC-1, BxPC-3, CFPAC-1 and HPAC cells was weak. Transfection efficiency of the vectors for human pancreatic cancer cell lines was not directly related to the CAR or integrin expression. However, transfection by Ad5/35GFP was significantly greater than by Ad5GFP at MOIs of 10 and 25 in all five human pancreatic cell lines. In conclusion, the Ad5/35GFP vector mediates more efficient gene transfer to human pancreatic cancer cells. These results may have implications for improving the efficiency of Ad-mediated gene transfer and developing adenoviral vectors.

Midkine promoter-based conditionally replicative adenovirus therapy for midkine-expressing human pancreatic cancer

Background

To develop a novel therapeutic strategy for human pancreatic cancer using a midkine promoter-based conditionally replicating adenovirus.

Methods

We examined midkine mRNA expression and midkine protein expression by seven human pancreatic cancer cell lines (AsPC-1, BxPC-3, CFPAC-1, HPAC, MIAPaCa-2, PANC-1, and Suit-2), as well as by non-cancerous pancreatic tissue and pancreatic cancers. Midkine promoter activity was measured in cancer cell lines by the dual luciferase reporter assay. Adenoviral transduction efficiency was assessed by fluorescent staining of cancer cell lines using adenovirus type 5 containing the green fluorescent protein gene (Ad5GFP). Replication of adenovirus type 5 containing the 0.6 kb midkne promoter (Ad5MK) was assessed by the detection of E1 protein in cancer cell lines. The cytotoxicity of Ad5MK for cancer cells was evaluated from the extent of growth inhibition after viral infection. Infection and replication were also assessed in nude mice with subcutaneous Suit-2 tumors by intratumoral injection of Ad5MK, Ad5GFP, or vehicle. E1a mRNA expression in the treated tumors and expression of the replication-specific adenoviral hexon protein were evaluated. Finally, the anti-tumor activity of Ad5MK against intraperitoneal xenografts of Suit-2 pancreatic cancer cells was examined after intraperitoneal injection of the virus.

Results

Both midkine mRNA expression and midkine protein expression were strong in AsPC-1 and CFPAC-1 cell liens, moderate in BxPC-3, HPAC, and Suit-2 cell lines, and weak in PANC-1 and MIAPaCa-2 cell lines. Expression of midkine mRNA was significantly stronger in pancreatic cancers than in non-cancerous pancreatic tissues. The relative luciferase activity mediated by the 0.6 kb midkne fragment in AsPC-1, PANC-1, and Suit-2 cell lines was approximately 6 to 20 times greater than that in midkne-negative MIAPaCa-2 cell lines. Pancreatic cancer cell lines exhibited a heterogeneous adenoviral transduction profile. E1A expression was higher in cell lines with strong midkine expression than in cell lines with weak midkine expression. Ad5MK showed much greater cytotoxicity for midkine-expressing Suit-2 and PANC-1 cell lines than for midkine-negative MIAPaCa-2 cell lines. In the Suit-2 subcutaneous xenograft model, expression of E1A was detected in Ad5MK-treated tumors, but not in untreated and Ad5GFP-treated tumors. In the Suit-2 intraperitoneal xenograft model, the Ad5MK group survived for significantly longer than the Ad5GFP, PBS, and untreated groups.

Conclusion

Ad5MK has an anti-tumor effect against human pancreatic cancer cell lines that express midkine mRNA. Midkine promoter-based conditionally replicative adenovirus might be a promising new gene therapy for pancreatic cancer.

A new technique for intraoperative continuous biliary drainage during pancreatoduodenectomy

BACKGROUND

The common hepatic duct is divided during the early stage of pancreatoduodenectomy. Complete and prolonged closure of the proximal common duct stump can cause liver damage in the course of this long operation, resulting in associated complications.

METHODS

We performed intraoperative continuous external bile drainage by a new method using a novel drainage clamp in 47 consecutive patients (drainage clamp group) and compared postoperative liver enzyme levels, inflammation markers, morbidity, and outcomes with those of a conventional clamp group (n = 40).

RESULTS

The drainage clamp group had significantly lower transaminase levels within the first 14 postoperative days than the conventional clamp group. The number of patients with elevated transaminase was significantly less in drainage clamp group than conventional clamp group (p < 0.001). There were no significant differences between these two groups in terms of mortality rates and postoperative morbidity.

CONCLUSION

Intraoperative complete closure of the common hepatic duct contributed to postoperative elevated transaminase levels, and the continuous decompression of the hepatic duct during pancreatoduodenectomy is beneficial to patients by avoiding liver dysfunction. The novel drainage clamp is a safe and useful tool for pancreatoduodenectomy and other operative procedure where extrahepatic bile duct is dissected.

Effect of the XIAP inhibitor Embelin on TRAIL-induced apoptosis of pancreatic cancer cells

BACKGROUND

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a potent inducer of apoptosis in a wide variety of tumor cells, while it has no toxicity for the majority of normal cells.Therefore, TRAIL may be a suitable agent for anticancer therapy. We previously reported that a number of pancreatic cancer cell lines show resistance to TRAIL-induced apoptosis via overexpression of XIAP and FLIP. The present study was conducted to further examine TRAIL-based therapeutic strategies by aiming to restore functional apoptotic pathways in resistant pancreatic cancer cells.

METHODS

In various pancreatic cancer cell lines, TRAIL-induced apoptosis was evaluated in the presence or absence of an XIAP-inhibitor (Smac peptide). Second, TRAIL-induced apoptosis was evaluated in TRAIL-resistant AsPC-1 cells with or without FLIP antisense. Third, the combined effect of Smac peptide and FLIP antisense was tested, and the activation of apoptosis-related caspases and poly (ADP-ribose) polymerase was evaluated. Finally, TRAIL-induced apoptosis was evaluated in the presence or absence of FLIP antisense and an XIAP inhibitor (embelin).

RESULTS

Smac peptide enhanced TRAIL-induced apoptosis in a dose-dependent manner for several pancreatic cancer cell lines, but showed no effect on TRAIL-resistant AsPC-1 cells. Smac peptide alone had no influence on cell viability. TRAIL-induced apoptosis was restored in TRAIL-resistant AsPC-1 cells by exposure to FLIP antisense, which suppressed the expression of FLIP. The effect of TRAIL was augmented by the combination of FLIP antisense and Smac peptide. Similarly, TRAIL-induced apoptosis was restored by the combination of FLIP antisense and embelin. Activation of apoptotic caspases and cleavage of poly (ADP-ribose) polymerase was observed after sensitization of TRAIL-resistant pancreatic cancer cells.

CONCLUSIONS

Pancreatic cancer cells gain resistance to TRAIL-induced apoptosis via expression of the antiapoptotic proteins XIAP and FLIP. Smac peptide and FLIP antisense could restore the apoptotic effect of TRAIL. An XIAP inhibitor, embelin, enhanced the effect of TRAIL in the presence of FLIP antisense. These findings may provide useful information for the development of TRAIL-based therapeutic strategies by restoring functional apoptotic pathways in resistant pancreatic cancer cells. In addition, a low molecular weight XIAP inhibitor like embelin could be a lead compound for the development of effective XIAP inhibitors.

Prognostic implication of para-aortic lymph node metastasis in resectable pancreatic cancer

BACKGROUND

The survival curve of patients who undergo surgical resection of pancreatic cancer displays a steep decline within 1 year and a relatively slow decline thereafter. The patients with a short survival time may have identifiable clinicopathologic factors that lead to rapid relapse.

STUDY DESIGN

We analyzed clinicopathologic factors in 133 patients who underwent margin-negative pancreatoduodenectomy with extended radical lymphadenectomy for invasive ductal carcinoma of the pancreas to detect factors that could be responsible for the short survival.

RESULTS

Tumor size, invasion of the anterior pancreatic capsule, retroperitoneal invasion, portal venous invasion, major arterial invasion, and metastasis to the para-aortic lymph nodes were variables associated with survival time in univariate analysis. Metastasis to the para-aortic lymph nodes was the single independent factor with a significant association with mortality in multivariate analysis. Some 84% of the patients who had positive para-aortic lymph nodes died within 1 year, versus 46% of the patients with negative nodes.

CONCLUSIONS

Although tumors that involve the para-aortic lymph nodes may technically be resectable, the expected postoperative survival time for most patients is less than 1 year. If para-aortic nodal metastasis is detected, alternative treatment strategies should be considered.

Forced expression of PDX-1 induces insulin production in intestinal epithelia

BACKGROUND

In the developmental stage, pancreas derives from the endodermal cells where the transcription factor, pancreatic duodenal homeobox gene-1 (pdx-1) is expressed. In adulthood, pdx-1 expression is localized to pancreatic beta cells, which is necessary for maintenance of beta cell function. Recently, ectopic expression of pdx-1 in the liver successfully induced insulin production and ameliorated hyperglycemia. Our study was designed to investigate the effects of forced expression of pdx-1 in ileal epithelia by adenovirus-mediated gene transfer.

METHODS

The recombinant, replication-deficient adenovirus carrying the pdx-1 gene was constructed using the COS-TPC method. ICR mice were treated with intraperitoneal injection of 220 mg/kg streptozotocin (STZ). After determining the hyperglycemia, a loop of ileum was constructed and the adenovirus solutions (Ad-pdx-1 and Ad-lacZ 1 x 10(8) PFU/body) were injected into the lumen of the ileal loop. In this model, immunohistochemical or fluorescent analyses of PDX-1 and insulin in the adenovirus-infected ileal epithelia were carried out. Reverse transcription polymerase chain reaction of pdx-1 and other pancreatic markers were investigated. Blood glucose concentrations were measured by drawing blood from ocular veins. Immunoreactive insulin extracted from the adenovirus-infected ileum was measured.

RESULTS

Ad-pdx-1 induced ectopic PDX-1 expression in the ileum. The PDX-1 positive cells in the ileal epithelia were positive for insulin; mRNA of insulin-1, insulin-2 and pdx-1 were expressed in mice infected with Ad-pdx-1. Hyperglycemia was improved in STZ-treated mice infected with Ad-pdx-1. Immunoreactive insulin in the ileum extract was increased significantly in mice with Ad-pdx-1.

CONCLUSIONS

Gene transfer of PDX-1 in intestinal epithelia could be a promising strategy for diabetes mellitus by inducing ectopic insulin producing cells.

Bcl-XL antisense oligonucleotides coupled with antennapedia enhances radiation-induced apoptosis in pancreatic cancer

BACKGROUND

Pancreatic cancer is highly resistant to radiation and chemotherapy, and its resistance reflects the enhancement of apoptosis inhibitory genes, including Bcl-2 family. Antennapedia (pAnt) is capable of almost 100% internalization into cells through the lipid bilayer without any cytotoxic effect. The aim of this study was to examine the effects of the Bcl-XL antisense oligonucleotide for radiosensitivity of in vitro and in vivo pancreatic cancer using oligonucleotide conjugated with antennapedia.

METHODS

In in vitro experiments, expression of Bcl-XL protein was examined in 5 pancreatic cancer cell lines. In AsPC-1 cells, internalization of the oligonucleotide was confirmed, and the effects of antennapedia-antisense (pAnt-AS) or antennapedia-scramble (pAnt-Scr) on Bcl-XL protein expression were examined. Cells were treated with pAnt-AS, pAnt-Scr or phosphorothioate antisense (S-AS) for 3 days, then the effects of irradiation on the cell survival, caspase-3 activity, and apoptotic index were evaluated. In AsPC-1 xenograft mice, pAnt-AS, pAnt-Scr, or S-AS was injected, and 5 or 10 Gy irradiation was added. Bcl-Xl protein expression was measured before irradiation. Apoptosis was evaluated at 48 hours after irradiation. On the 14th day after 10-Gy irradiation, tumor wet weight was measured, and tumor growth was estimated over 5 weeks.

RESULTS

In in vitro experiments, all pancreatic cancer cell lines expressed Bcl-XL protein. pAnt-AS was internalized into AsPC-1 cells within 2 hours. pAnt-AS at 10 mumol/L reduced more than 90% of the Bcl-XL protein in AsPC-1 cells, whereas pAnt-Scr or S-AS treatment at the same concentration reduced as much as 10% of the Bcl-XL protein. Treatment with pAnt-AS followed by irradiation significantly reduced cell viability when compared with that of pAnt-Scr or S-AS. Caspase-3 activity was significantly upregulated in the pAnt-AS-treated group (P = .033). The rate of nuclear fragmentation was significantly higher in the pAnt-AS group (P = .013). In in vivo experiments, Bcl-XL protein was reduced about 40% in the pAnt-AS-treated mice. Tumor doubling time of the pAnt-AS-treated mice was elongated by 10-Gy irradiation. The tumor wet weight of mice treated with pAnt-AS and 10-Gy irradiation was significantly reduced when compared with mice treated with pAnt-Scr and 10-Gy irradiation (P = .046). The apoptosis index at 48 hours after irradiation was significantly increased in pAnt-AS-treated mice (P < .01).

CONCLUSIONS

The results suggest that, when coupled with antennapedia, the antisense oligonucleotide against Bcl-XL could be a good therapeutic tool for radiosensitization of pancreatic cancer.

[Surgical treatment of carcinoma of the pancreas]

Invasive ductal carcinoma of the pancreas (pancreatic cancer) is mainly treated by operative resection, radio-chemotherapy, or chemotherapy. The survival rate of the patients with each treatment is not good when compared with that in other cancers. Meanwhile, it is still true that surgical resection remains the only method offering pancreatic cancer patients long-term survival or cure. The indications for surgical resection should be considered based on whether margin-free resection can be achieved in individual patients. In addition, the volume of pancreatic cancer patients treated at the institution and the surgeon's personal experience may greatly affect the decision. A recent randomized clinical trial from Japan revealed that surgical resection has a survival advantage over chemo-radiation therapy for locally advanced pancreatic cancer, which is defined as stage IVa in the fourth Japanese edition of the Classification of Pancreatic Carcinoma. Moreover, guidelines for clinical practice for pancreatic cancer by the Japan Pancreas Society have been issued very recently. In addition, the surgical indications should be reevaluated in combination with the adjuvant or neoadjuvant chemotherapy in future.

Clinical significance of focal adhesion kinase in resectable pancreatic cancer

Focal adhesion kinase (FAK) is a non-receptor, cytoplasmic protein tyrosine kinase that is involved in the regulation of cellular signaling, migration, apoptosis, and cell cycle progression. Previous reports have shown that FAK is expressed in various kinds of cancer tissues and cancer cell lines; however, no information is available about human pancreatic carcinoma specimens. Tissue such specimens were obtained from 50 patients who underwent pancreatic resection for pancreatic invasive ductal carcinoma at our institute from 1996 to 2002. Immunohistochemical analysis of FAK was performed in the resected specimens. Focal adhesion kinase expression in seven human pancreatic cancer cell lines was analyzed by reverse transcription polymerase chain reaction (PCR) analysis and Western blot analysis. Focal adhesion kinase expression was detected in 24 of 50 cases (48%). There was a statistically significant correlation between FAK expression and tumor size (P=0.004), although FAK expression did not significantly correlate with other factors such as tumor histological grade, lymph node metastasis, distant metastasis, histological stage, and overall survival. Reverse transcription PCR analysis and Western blot analysis showed that FAK was expressed in all seven pancreatic cancer cell lines. Focal adhesion kinase expression was not directly related to clinicopathological factors except tumor size in pancreatic carcinoma. Focal adhesion kinase expression may not be a prognostic marker for pancreatic cancer patients.

In vivo antitumor effect of the mTOR inhibitor CCI-779 and gemcitabine in xenograft models of human pancreatic cancer

Mammalian target of rapamycin (mTOR) is considered to be a major effector of cell growth and proliferation that controls protein synthesis through a large number of downstream targets. We investigated the expression of the phosphatidylinositol 3'-kinase (PI3K)/mTOR signaling pathway in human pancreatic cancer cells and tissues, and the in vivo antitumor effects of the mTOR inhibitor CCI-779 with/without gemcitabine in xenograft models of human pancreatic cancer. We found that the Akt, mTOR and p70 S6 kinase (S6K1) from the PI3K/mTOR signaling pathway were activated in all of the pancreatic cancer cell lines examined. When surgically resected tissue specimens of pancreatic ductal adenocarcinoma were examined, phosphorylation of Akt, mTOR and S6K1 was detected in 50, 55 and 65% of the specimens, respectively. Although CCI-779 had no additive or synergistic antiproliferative effect when combined with gemcitabine in vitro, it showed significant antitumor activity in the AsPC-1 subcutaneous xenograft model as both a single agent and in combination with gemictabine. Furthermore, in the Suit-2 peritoneal dissemination xenograft model, the combination of these 2 drugs achieved significantly better survival when compared with CCI-779 or gemcitabine alone. These results demonstrate promising activity of the mTOR inhibitor CCI-779 against human pancreatic cancer, and suggest that the inhibition of mTOR signaling can be exploited as a potentially tumor-selective therapeutic strategy.

Manipulation of the small intestine as a cause of the increased inflammatory response after open compared with laparoscopic surgery

BACKGROUND

Laparoscopic surgery of the gastrointestinal tract involves a reduced immune response compared with open surgery. The aim of this study was to assess manual handling of the gut in open procedures as the principal cause of the enhanced immune response.

METHODS

Eighteen Landrace pigs underwent gastrectomy by three different methods: conventional open wound with bowel manipulation, laparoscopically assisted gastrectomy, and gastrectomy without manipulation using a combination of open wound and laparoscopic surgical devices. Local inflammatory changes were assessed by ascites formation, intestinal adhesion development and intestinal inflammatory gene expression. Associated systemic inflammatory changes were determined by measuring portal and systemic plasma endotoxin levels, plasma inflammatory cytokine levels, liver inflammatory gene expression and transaminase levels.

RESULTS

Significantly more postoperative intra-abdominal fluid and adhesions were seen in the open group. The expression of inflammatory cytokines was significantly greater in the intestine and liver in the open group. Portal and systemic levels of endotoxin, inflammatory cytokines and transaminases were also higher.

CONCLUSION

Manual handling of organs during gastrectomy is an important contributor to the molecular and humoral inflammatory response to surgery, supporting the use of minimally invasive techniques in gastrointestinal surgery.

Downregulation of survivin by siRNA diminishes radioresistance of pancreatic cancer cells

BACKGROUND

Survivin is a member of the inhibitor of apoptosis protein family, which inhibits apoptosis and regulates cell division. Survivin is expressed by the majority of human cancers, including pancreatic adenocarcinoma. We have reported that its expression is correlated with shorter survival of pancreatic cancer patients, so regulation of this molecule could be a new strategy for fighting pancreatic cancer.

METHODS

In 3 pancreatic cancer cell lines (AsPC-1, SUIT-2, and Panc-1), survivin promoter activity was determined by the luciferase reporter assay, and survivin messenger RNA (mRNA) expression was examined by quantitative reverse transcriptase-polymerase chain reaction. The dose-dependent cytotoxity of radiation was also assessed, while caspase-3 activity and induction of DNA fragmentation were evaluated. Furthermore, the effect of silencing or nonsilencing short interfering RNA (siRNA) expression plasmids directed against the survivin gene on AsPC-1 cells, the most radioresistant cell line, was evaluated.

RESULTS

Pancreatic cancer cell lines expressed varying levels of survivin mRNA in association with transcriptional activity of the survivin promoter. Both survivin promoter activity and mRNA expression were correlated with tumor cell radiosensitivity. Radiation significantly increased survivin promoter activity and survivin mRNA expression in all cell lines. Radiation induced a significant increase in caspase-3 activity and DNA fragmentation in AsPC-1 cells. After silencing siRNA treatment of AsPC-1 cells (AS-S cells), there was a significant decrease in survivin mRNA expression and increase in caspase-3 activity, compared with the effect of nonsilencing scramble siRNA on AsPC-1 cells (AS-NS cells). AS-S cells were more radiosensitive than AS-NS cells. Radiation induced higher caspase-3 activity and more DNA fragmentation in AS-S cells, compared with AS-NS cells.

CONCLUSIONS

Survivin may play an important role as 1 of the radioresistance factors. Downregulation of survivin by siRNA can diminish the radioresistance of pancreatic cancer cells, so combined therapy with survivin inhibition and radiation may be useful for the treatment of pancreatic cancer.

Pancreatic epithelial cells can be converted into insulin-producing cells by GLP-1 in conjunction with virus-mediated gene transfer of pdx-1

BACKGROUND

Glucagonlike peptide-1 (GLP-1) stimulates insulin secretion and proliferation by islet cells in vitro and in vivo, associated with an activation of pancreatic duodenal homeobox gene-1 (pdx-1) function. The effect of GLP-1 on the conditionally immortalized pancreatic epithelial cells (IMPE cells) is not clear when they are treated in conjunction with the adenovirus-mediated gene transfer of pdx-1.

METHODS

IMPE cells were established from the pancreas of H-2K(b)-tsA58 transgenic mice. IMPE cells were maintained at 33 degrees C with 10 U/mL interferon (IFN)-gamma and the experiments were performed at 39 degrees C without IFN-gamma. IMPE cells were infected with 20 multiplicities of Ad-pdx-1 or control Ad-lacZ at 39 degrees C without IFN-gamma and were incubated with various concentrations of GLP-1. After 48 hours, immunofluorescence and reverse transcriptase-polymerase chain reaction for insulin and pdx-1 expression were examined. Immunoreactive insulin in the cell lysate and supernatant was also analyzed. The glucose concentration in the culture medium was changed to test the insulin secretory responsiveness of the IMPE cells.

RESULTS

The treatment with GLP-1 in conjunction with Ad-pdx-1 induced insulin production by IMPE cells, but the treatment with either GLP-1 or Ad-pdx-1 alone failed to induce insulin production. Insulin production and secretion were increased by GLP-1 and by glucose in a dose-dependent manner. In addition, the insulin-producing IMPE cells acquired a rapid insulin secretory responsiveness to the changes of extracellular glucose concentration.

CONCLUSIONS

GLP-1 and pdx-1 work together to induce insulin-producing cells from IMPE cells, which bear unique characteristics of pancreatic ductal cells. The results suggest that GLP-1 may be another important determiner of pancreatic endocrine differentiation as is pdx-1.

Expression and prognostic value of tuberous sclerosis complex 2 gene product tuberin in human pancreatic cancer

BACKGROUND

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutation of either of 2 tumor suppressor genes, TSC1 or TSC2, which encode hamartin and tuberin, respectively. Several studies have shown that tuberin functions independently of hamartin and inhibits signaling pathways via the mammalian target of rapamycin, a critical regulator of cell proliferation. Recent studies have revealed that the signaling pathways regulating the mammalian target of rapamycin such as Akt and S6K1 are frequently activated in pancreatic cancer. We hypothesized that tuberin might be involved in the proliferation and survival of pancreatic cancer cells.

METHODS

We immunohistochemically examined the expression of tuberin in 42 pancreatic cancerous and noncancerous pancreatic tissue specimens using an antituberin antibody. The correlations between tuberin expression and various clinicopathologic features, including survival, were evaluated. Reverse transcriptase-polymerase chain reaction was performed to evaluate the level of tuberin expression in paired samples of pancreatic cancer and noncancerous tissue.

RESULTS

Twenty-four of the 42 pancreatic cancer samples (57%) were negative for tuberin expression. The patients with tuberin-negative tumors had a significantly higher incidence of pT3 or pT4 disease (primary tumor extent by the TNM classification) than those with tuberin-positive tumors (P = .024). Female patients had a significantly higher incidence of tuberin-positive tumors than male patients (P = .014). The survival rate of the tuberin-positive group tended to be better than that of the tuberin-negative group, but there was no significant difference (P = .4). Expression of TSC2 in cancer tissue was lower than in the corresponding noncancerous tissue for 7 of the 9 samples examined.

CONCLUSIONS

This study demonstrates that reduced expression of tuberin might be involved in the progression of pancreatic cancer. Accordingly, tuberin may provide a new therapeutic target in patients with this type of cancer.

Regulation of the resistance to TRAIL-induced apoptosis as a new strategy for pancreatic cancer

BACKGROUND

Tumor necrosis factor-related, apoptosis-inducing ligand (TRAIL) is a potent inducer of apoptosis in a wide variety of tumor cells, but it does not cause toxicity in the majority of normal cells. Therefore, TRAIL could become a suitable agent for anticancer therapies. However, a number of tumor cell lines are known to be resistant to TRAIL-induced apoptosis. The purpose of this study was to determine the mechanisms of resistance to TRAIL in pancreatic cancer cells.

METHODS

In human pancreatic cancer cell lines, the sensitivity to TRAIL-induced apoptosis was tested. The expression of TRAIL receptors (DR4, DR5, DcR1, and DcR2) and the expression of death signal-transducing proteins were investigated. In the TRAIL-resistant pancreatic cancer cells, effects of cycloheximide, a protein synthesis inhibitor, on death signal-transducing proteins were tested. Finally, the effects of the combined treatment with cycloheximide and TRAIL on the induction of apoptosis and on the expression of death signal-transducing proteins were examined.

RESULTS

Pancreatic cancer cells responded to TRAIL in a different way. Resistant cell lines, AsPC-1, Suit-2, and CFPAC-1, expressed higher levels of FLIP-S protein, one of the splice variants of FLIP. Cycloheximide reduced the expression of FLIP in the resistant cells. Combined treatment with cycloheximide and TRAIL induced cleaved forms of caspases and simultaneously restored the sensitivity to TRAIL-induced apoptosis in the resistant cells.

CONCLUSIONS

Pancreatic cancer cells are resistant to TRAIL-induced apoptosis via strong expression of the anti-apoptotic protein FLIP-S. Suppression of FLIP-S by cycloheximide restored sensitivity to TRAIL-induced apoptosis in resistant cancer cells. These findings may provide useful information for the development of TRAIL-based therapeutic strategies aimed at restoring the functionality of apoptotic pathways in pancreatic cancer cells.

Analysis of E-, N-cadherin, alpha-, beta-, and gamma-catenin expression in human pancreatic carcinoma cell lines

OBJECTIVES

Cadherins are cell surface glycoproteins that mediate Ca2+-dependent, homophilic cell-cell adhesion. The classic cadherins interact with either beta-catenin or gamma-catenin, which is bound to alpha-catenin that links the complex to the actin cytoskeleton. It has been reported that alteration in cadherins/catenins function or expression is found in the neoplastic process as a step in metastasis. The aim of this study was to analyze the expressions of E- and N-cadherins and catenins in human pancreatic cancer cell lines.

METHODS

We examined the expression of cadherins and catenins in 7 human pancreatic cancer cells by RT-PCR, Western blotting, and immunocytochemistry. The interactions between cadherins and beta-catenin were assessed by immunoprecipitation.

RESULTS

E-cadherin was expressed in all cell lines except for MIAPaCa-2, whereas N-cadherin was expressed in Capan-2, CFPAC-1, BxPC-3, and PANC-1. The alpha-, beta-, and gamma-catenins were expressed and cadherins/beta-catenin interactions were detected in all cadherin-expressing cells. Immunocytochemical analysis showed membranous expression of cadherins and catenins.

CONCLUSION

The decreased or loss of cadherins and catenins expression could be involved in the tumor progression and metastasis, although these events may occur in in vivo conditions by interaction between cancer cells and extracellular matrices.

N-cadherin expression and epithelial-mesenchymal transition in pancreatic carcinoma

PURPOSE

Loss of intercellular adhesion and increased cell motility promote tumor cell invasion. In the present study, E- and N-cadherin, members of the classical cadherin family, are investigated as inducers of epithelial-to-mesenchymal transition (EMT) that is thought to play a fundamental role during the early steps of invasion and metastasis of carcinomas. Cell growth factors are known to regulate cell adhesion molecules. The purpose of the study presented here was to investigate whether a gain in N-cadherin in pancreatic cancer is involved in the process of metastasis via EMT and whether its expression is affected by growth factors.

EXPERIMENTAL DESIGN

We immunohistochemically examined the expression of N- and E-cadherins and vimentin, a mesenchymal marker, in pancreatic primary and metastatic tumors. Correlations among the expressions of N-cadherin, transforming growth factor (TGF)beta, and fibroblast growth factor 2 was evaluated in both tumors, and the induction of cadherin and vimentin by growth factors was examined in cultured cell lines.

RESULTS

N-cadherin expression was observed in 13 of 30 primary tumors and in 8 of 15 metastatic tumors. N-cadherin expression correlated with neural invasion (P = 0.008), histological type (P = 0.043), fibroblast growth factor expression in primary tumors (P = 0.007), and TGF expression (P = 0.004) and vimentin (P = 0.01) in metastatic tumors. Vimentin, a mesenchymal marker, was observed in a few cancer cells of primary tumor but was substantially expressed in liver metastasis. TGF stimulated N-cadherin and vimentin protein expression and decreased E-cadherin expression of Panc-1 cells with morphological change.

CONCLUSION

This study provided the morphological evidence of EMT in pancreatic carcinoma and revealed that overexpression of N-cadherin is involved in EMT and is affected by growth factors.

Survivin expression is a prognostic marker in pancreatic cancer patients

BACKGROUND

In this study, we assessed survivin expression in pancreatic cancer specimens from patients who underwent either pancreatic resection alone or pancreatic resection plus postoperative radiation therapy (PORT) to evaluate whether survivin expression is predictive of sensitivity to PORT and outcome in pancreatic cancer patients.

METHODS

Fifty-two patients who underwent pancreatic resection for ductal adenocarcinomas were included in this study. Forty-seven pancreatic ductal adenocarcinoma and 5 normal pancreatic tissues were evaluated for survivin expression by immunohistochemistry. Then the relationship between survivin expression and clinicopathologic data were analyzed.

RESULTS

Sixty-eight percent (32/47) of pancreatic cancer tissues were positive for survivin expression; 32% (15/47) were negative. Normal pancreatic exocrine tissues were negative for survivin expression (0/5). Survival of the patients with positive survivin was significantly shorter than those with negative survivin (P = .02). Survivin was an independent variable that correlated with overall survival (P = .01). There was no difference in survival time between patients with and without PORT. Likely, PORT showed no impact on survival time in survivin-positive patients (P = .12) as well as in survivin-negative patients (P = .95).

CONCLUSIONS

The results suggest that survivin expression in pancreatic cancer tissues could be a useful prognostic marker in pancreatic cancer patients.

Chronic exposure of transforming growth factor beta 1 confers a more aggressive tumor phenotype through downregulation of p21(WAF1/CIP1) in conditionally immortalized pancreatic epithelial cells

BACKGROUND

Recent studies have demonstrated that transforming growth factor beta 1 (TGF-beta1) expression is markedly enhanced in invasive ductal pancreatic adenocarcinomas, although the precise role of TGF-beta1 in pancreatic carcinogenesis remains unclear. We analyzed TGF-beta1 expression in pancreatic intraepithelial neoplasias (PanINs) and the effects of chronic TGF-beta1 exposure on conditionally immortalized pancreatic epithelial (IMPE) cells.

METHODS

Sixty-one PanIN lesions were immunohistochemically stained with a polyclonal rabbit antibody against human TGF-beta1. Growth-inhibitory effects of short-term exposure to TGF-beta1 were examined in IMPE cells. IMPE cells resistant to TGF-beta1 (IMPE-Tr cells) were generated by continuous exposure to 1 ng/mL of TGF-beta1 for more than 50 days. Phenotypic alterations of IMPE-Tr cells were examined by soft agar and Matrigel assay and Western blot analysis. IMPE and IMPE-Tr cells were injected subcutaneously into nude mice for an in vivo tumorigenicity assay.

RESULTS

Forty-six percent of PanINs (28/61) were positive for TGF-beta1 expression, whereas all the epithelia of normal pancreatic ducts were negative. TGF-beta1 treatment showed the marked growth-inhibitory effects (>75%) in IMPE cells, whereas its effects were not observed in IMPE-Tr cells. IMPE-Tr cells were more spindle shaped compared with IMPE cells. In soft agar and Matrigel, formations of many colonies were observed in IMPE-Tr cells, but not in IMPE cells. Interestingly, the expression of p21(WAF1/CIP1) was induced by short-term exposure to TGF-beta1 in IMPE cells, whereas the induction was decreased in IMPE-Tr cells. All of the IMPE-Tr cell-injected mice (5/5) had subcutaneous tumors, although no tumor was found in the IMPE cell-injected mice.

CONCLUSIONS

TGF-beta1 expression in PanINs and neoplastic transformation of IMPE cells by long-term exposure to TGF-beta1 suggest that TGF-beta1 may act as a tumor promoter in the early stage of pancreatic carcinogenesis.

Hepatic regeneration and enforced PDX-1 expression accelerate transdifferentiation in liver

BACKGROUND

Pancreatic duodenal homeobox gene-1 (PDX-1) has a dual task as a key regulator in pancreatic organogenesis and in functional maintenance of beta cells in adults. Recent studies have shown a close lineage relationship between the liver and the pancreas. In this study, we analyzed the plasticity of the liver by enforced expression of PDX-1 in streptozotocin (STZ)-treated mice under the condition of hepatic regeneration.

METHODS

Replication-deficient adenoviruses were constructed by the cosmid-adenoviral DNA terminal protein complex method. Mice were treated with STZ (200 mg/kg ip), and a 40% partial hepatectomy was performed at day 0. After 24 hours, Ad-pdx-1 or Ad-lacZ 2.0 x 10(9) PFU/body was injected via the tail vain into nontreated (control), STZ-treated, or STZ plus partial hepatectomy (Hx)-treated ICR mice. After 7 and 14 days, expression of PDX-1 and islet hormones was examined by immunohistologic and reverse transcription-polymerase chain reaction analysis. Blood glucose concentrations were measured every 2 days. Immunoreactive insulin (IRI) of serum and liver extract was measured by ELISA.

RESULTS

Most hepatocytes of Ad-pdx-1-infected mice were positive for PDX-1 expression by immunohistochemistry. In nontreated mice, very few cells expressed insulin and other hormones. In contrast, insulin and somatostatin were expressed in STZ-treated mice, and more cells were expressed in STZ plus Hx-treated mice. In addition, other beta-cell markers like GLUT2 and glucokinase were observed. Hyperglycemia was improved in STZ-treated mice and STZ plus Hx-treated mice. IRI of serum and liver extract was increased in STZ-treated mice and STZ plus Hx-treated mice. The insulin positive area of the liver in STZ plus Hx-treated mice was larger than that in nontreated and STZ-treated mice.

CONCLUSIONS

Ectopic PDX-1 expression alone may be insufficient to induce insulin-producing cells in the liver. STZ-induced hyperglycemia plus partial hepatectomy that leads to diabetic state and hepatic regeneration may stimulate the transdifferentiation of liver cells into insulin-producing cells.

Conditional transformation of mouse pancreatic epithelial cells: an in vitro model for analysis of genetic events in pancreatocarcinogenesis

Pancreatic ductal adenocarcinomas arise through the accumulation of certain genetic alterations including ras, p16, p53, and DPC4. We found that activation of ras and inactivation of p53 could cooperatively induce in vitro tumorigenicity in conditionally immortalized pancreatic epithelial (IMPE) cells. IMPE cells were established from transgenic mice bearing a temperature-sensitive mutant SV40 Large T (LT) antigen. IMPE cells grew continuously under permissive conditions (33 degrees C with interferon-gamma), but rapidly suffered growth arrest under non-permissive conditions (39 degrees C without interferon-gamma). The cells showed strong expression of E-cadherin and beta-catenin as epithelial markers, and cytokeratin 19, a specific ductal cell marker. Cell proliferation under permissive conditions was associated with down-regulation of p21 expression through inactivation of p53 after overexpression of LT antigen. Intriguingly, the shift from the permissive to non-permissive culture conditions caused G2/M arrest of IMPE cells. Although the cells did not form colonies when cultured in soft agar without activation of ras, cells with ras activation via an adenovirus vector formed colonies under permissive conditions. These findings suggest that activation of ras and inactivation of p53 can cooperatively induce anchorage-independent growth of IMPE cells. This cell line might be useful for studying the processes involved in pancreatocarcinogenesis.

Metastin and its variant forms suppress migration of pancreatic cancer cells

Metastin, a post-translationally modified variant of KiSS1, was recently identified as an endogenous peptide agonist for a novel G-protein coupled receptor, hOT7T175 (AXOR12, GPR54). In this study, we analyzed the role of KiSS1 and hOT7T175 in both pancreatic cancer tissues and pancreatic cancer cell lines. Furthermore, we synthesized novel short variant forms of metastin and tested the inhibitory effect of those variants on in vitro cell functions that are relevant to metastasis. Pancreatic cancer tissues showed significantly lower expression of KiSS1 mRNA than normal tissues (p=0.018), while cancer tissues showed significantly higher expression of hOT7T175 mRNA than normal pancreatic tissues (p=0.027). In human pancreatic cancer cell lines, KiSS1 mRNA was highly expressed in 2 out of 6 pancreatic cancer cell lines, while hOT7T175 mRNA was expressed in all cell lines at various degrees. PANC-1 cells showed the highest expression of hOT7T175. Exogenous metastin did not suppress cell proliferation but significantly reduced the in vitro migration of PANC-1 cells (p<0.01). Metastin induced activation of ERK1 in PANC-1 and AsPC-1 cells. Finally, we synthesized 3 novel short variant forms of metastin, FM053a2TFA, FM059a2TFA, and FM052a4TFA. These metastin variants significantly suppressed the migration of PANC-1 cells and activated ERK1. These data suggest that the metastin receptor, hOT7T175, is one of the promising targets for suppression of metastasis, and that small metastin variants could be an anti-metastatic agent to pancreatic cancer.

Localization of MyoD, myogenin and cell cycle regulatory factors in hypertrophying rat skeletal muscles

AIM

MyoD, myogenin, proliferating cell nuclear antigen (PCNA) and cyclin-dependent kinase inhibitor p21 (p21) proteins are key molecules in inducing the growth of myogenic cells in vitro. However, it has not been determined which cell types express these factors in hypertrophying skeletal muscles in vivo.

METHODS

Using immunohistochemical techniques, we examined the spatial and temporal expression patterns of MyoD, myogenin, PCNA and p21 proteins in functionally overloaded rat plantaris muscles induced by ablation of the soleus and gastrocnemius muscles.

RESULTS

MyoD and myogenin were detected in myonuclei located inside the dystrophin-positive plasma membrane of myofibres, m-cadherin-positive satellite cell nuclei and nuclei located in the interstitial spaces between myofibres on days 1, 3, 5 and 7 post-surgery. Entry of satellite cells into the cell cycle was indicated by the expression of PCNA on day 3 post-surgery, and withdrawal from the cell cycle was observed by the expression of p21 in satellite cell nuclei on day 5 post-surgery. However, the expression of both PCNA and p21 in satellite cell nuclei disappeared on day 7 post-surgery.

CONCLUSION

These results indicate that proliferated satellite cell-derived myoblasts and undefined myogenic cells located in the interstitial spaces may contribute to an increase in myonuclear number and/or hyperplasia. Furthermore, we provide evidence that all of myonuclei, satellite cells and undefined myogenic cells express both MyoD and myogenin proteins. These results suggest that continual expression of MyoD and myogenin proteins in these cells is an essential molecular event which induces the successful hypertrophy of skeletal muscles.

CXCR4 antagonist inhibits stromal cell-derived factor 1-induced migration and invasion of human pancreatic cancer

The stromal cell-derived factor-1 (SDF-1)/CXCR4 system is implicated in various instances of cell migration in mammals, including the migration of lymphocytes and the formation of metastases. We have recently synthesized a potent novel CXCR4 antagonist, TN14003. The purpose of this study was to investigate the role of SDF-1/CXCR4 axis in the pancreatic cancer metastasis via cell migration and invasion, and the inhibitory effect of TN14003 on pancreatic cancer cell metastasis. The expression of CXCR4 was detected in six pancreatic cancer cell lines by Western blotting and immunocytochemistry. In migration and invasion assays, SDF-1 stimulated both migration and invasion of cancer cells in a dose-dependent manner. The maximal effect of SDF-1 was observed at 100 ng/ml. SDF-1-induced migration and invasion of cancer cells were completely blocked by 100 nm TN14003. The stimulatory effect of SDF-1 on cancer migration and the inhibitory effect of TN14003 were mediated via the alteration in phosphorylation of mitogen-activated protein kinases. Treatment of cancer cells with 100 ng/ml SDF-1 resulted in a significant increase of actin polymerization, which was reduced by 100 nm TN14003. SDF-1 enhanced cancer cell adhesion to laminin, which was not reversed by TN14003. Taken together, SDF-1/CXCR4 axis is involved in pancreatic cancer metastasis through migration and invasion. The small molecule antagonists against CXCR4 such as TN14003 might be an effective anti-metastatic agent for pancreatic cancer.

CXCR4 antagonist inhibits stromal cell-derived factor 1-induced migration and invasion of human pancreatic cancer

The stromal cell-derived factor-1 (SDF-1)/CXCR4 system is implicated in various instances of cell migration in mammals, including the migration of lymphocytes and the formation of metastases. We have recently synthesized a potent novel CXCR4 antagonist, TN14003. The purpose of this study was to investigate the role of SDF-1/CXCR4 axis in the pancreatic cancer metastasis via cell migration and invasion, and the inhibitory effect of TN14003 on pancreatic cancer cell metastasis. The expression of CXCR4 was detected in six pancreatic cancer cell lines by Western blotting and immunocytochemistry. In migration and invasion assays, SDF-1 stimulated both migration and invasion of cancer cells in a dose-dependent manner. The maximal effect of SDF-1 was observed at 100 ng/ml. SDF-1-induced migration and invasion of cancer cells were completely blocked by 100 nM TN14003. The stimulatory effect of SDF-1 on cancer migration and the inhibitory effect of TN14003 were mediated via the alteration in phosphorylation of mitogen-activated protein kinases. Treatment of cancer cells with 100 ng/ml SDF-1 resulted in a significant increase of actin polymerization, which was reduced by 100 nM TN14003. SDF-1 enhanced cancer cell adhesion to laminin, which was not reversed by TN14003. Taken together, SDF-1/CXCR4 axis is involved in pancreatic cancer metastasis through migration and invasion. The small molecule antagonists against CXCR4 such as TN14003 might be an effective anti-metastatic agent for pancreatic cancer.

Transcriptional expression of survivin and its splice variants in brain tumors in humans

OBJECT

Survivin, one of the apoptosis inhibitor proteins, has been detected in most cancers in humans. In addition, two splice variants (survivin-2B and survivin-deltaEx3) have been identified. The authors investigated the transcription levels of survivin messenger (m)RNA and its splice variants in nine tumor cell lines, including gliomas, and in 25 brain tumor samples, by performing quantitative reverse transcription-polymerase chain reaction. The correlation between transcript expression levels and pathological findings were also analyzed.

METHODS

Transcription levels were measured using primer pairs specific for survivin and either of its splice variants and were normalized to the glyceraldehyde 6-phosphate dehydrogenase. Among the tumor cell lines tested, glioblastoma cell lines showed the highest levels of survivin expression. Among brain tumor samples studied, survivin was preferentially expressed in malignant brain tumors and gliomas. The relative expression level of survivin-deltaEx3/survivin was significantly higher in malignant than in benign brain tumor samples. Expression patterns were dominant for survivin-deltaEx3 in malignant brain tumors and dominant for survivin-2B in benign ones. A significant linear correlation between survivin mRNA expression and MIB-1 labeling index was demonstrated in all brain tumor samples.

CONCLUSIONS

The authors' results indicate that quantifying the levels of survivin and its splice variants is useful for the prediction of the cell biological malignancy of gliomas, independent of their pathological features.

Endogenous decoy receptor 3 blocks the growth inhibition signals mediated by Fas ligand in human pancreatic adenocarcinoma

Many cancers are resistant to Fas-mediated apoptosis despite the expression of Fas. To investigate the mechanisms by which Fas signals are attenuated, we focused on decoy receptor 3 (DcR3). DcR3 is a soluble receptor against Fas ligand belonging to the tumor necrosis factor receptor superfamily and overexpresses in some forms of cancers. Exogenous DcR3 inhibits Fas-mediated apoptosis in Fas-sensitive Jurkat cells. In our study, we examined the expression and function of DcR3 in pancreatic cancers. TaqMan RT-PCR showed that DcR3 mRNA was highly expressed in pancreatic cancer cell lines (71%) and tissues (67%). Its expression significantly correlated with cancer invasion to veins. Western blotting showed that the DcR3 protein was produced and secreted in 4 of 6 cell lines. The protein expressions were compatible with the mRNA expression. Five of 7 pancreatic cancer cell lines became sensitive to agonistic anti-Fas antibody (CH-11) to various extents, without Fas upregulation, when exposed to CH-11 for 48 hr after pretreatment with IFNgamma. Four of 7 pancreatic cancer cell lines were inhibited from growing, compared to control cells, when cocultured with membrane-bounded Fas ligand (mFasL) transfected lymphomas for 48 hr after pretreatment with IFNgamma. DcR3 reduced this growth inhibition when added exogenously. Regression analysis showed that the DcR3 expression significantly correlated with the sensitivity to mFasL, and not to CH-11. These results suggest that DcR3 is highly expressed in many pancreatic cancers and endogenous DcR3 blocks the growth inhibition signals mediated by mFasL. DcR3 can be a candidate target molecule for the therapeutic intervention.

RECK expression in pancreatic cancer: its correlation with lower invasiveness and better prognosis

BACKGROUND

The reversion-inducing cysteine-rich protein with Kazal motifs (RECK) gene was initially isolated as a transformation suppressor gene. The RECK gene is expressed widely in normal organs but is undetectable in many tumor-derived cell lines. When artificially expressed in such cell lines, RECK negatively regulates at least matrix metalloprotease (MMP)-9, MMP-2, and MT1-MMP activation and suppresses the invasive and metastatic potentials of these cells. Clinical relevance of these observations, however, is yet to be established. The aim of this study was to examine RECK expression in pancreatic cancer, where intensive invasiveness and metastasis are frequently observed, and investigate its clinical significance. We also analyzed the correlation between RECK expression and MMP activation.

METHODS

(a) RECK expression in surgically resected tissue samples of invasive ductal carcinomas of the pancreas (n = 50) was examined immunohistochemically, and its correlation with clinicopathological factors was analyzed; and (b) gelatin zymography was used for the detection of latent and activated forms of MMP-2 and MMP-9 in some of the tissue samples (n = 33). The gelatinase activity was quantified by densitometory, and the ratio of intensity of the active MMP-2 band to the total intensity of the pro- and active MMP-2 bands was evaluated as an indicator of MMP-2 activation. The MMP-9 activation was also studied.

RESULTS

Among the 50 ductal carcinoma samples, 26 (52%) were stained positive for RECK. In the normal pancreas, both acinar and beta cells were stained positive, but ductal cells did not. Tumors with positive RECK staining were significantly less invasive as compared with RECK-negative tumors (P = 0.0438). Importantly, patients who had tumors with high RECK expression showed significantly better prognosis than those who had RECK-negative tumors (P = 0.0463, by Log-rank test). Zymographic analysis indicated significant inverse correlation between the level of RECK expression and extent of MMP-2 activation (P = 0.0374).

CONCLUSIONS

Our findings support the hypothesis that the RECK protein has negative effects on the invasiveness of pancreatic cancer by inhibiting MMP-2 activation and suggest the potential value of RECK as a prognostic molecular marker for pancreatic cancer.

All-trans retinoic acid induces differentiation of ducts and endocrine cells by mesenchymal/epithelial interactions in embryonic pancreas

Retinoids during the embryonic period act as a mesenchymal inducer in many organs, including kidney, lung, central nervous system, and gut. Retinoic acid (RA) demonstrates insulinotropic effects in adult pancreas, but only a limited study has elucidated its role in pancreatic organogenesis. In this study, we have analyzed the existence of RA-signaling machinery in embryonic pancreas and evaluated its role using in vitro tissue culture experiments. Here we show the presence of endogenous retinaldehyde dehydrogenase 2 (RALDH2), the most effective RA-synthesizing enzyme, RA-binding proteins, and RA receptors (RARs) in embryonic pancreatic tissue. RALDH2 is expressed exclusively in the mesenchyme. Exogenously added all-trans-retinoic acid (atRA) in tissue culture experiments stimulated differentiation of endocrine and duct cells and promoted apoptotic cell death of acinar tissue. Furthermore, we demonstrate that atRA upregulates the PDX-1 expression. Taken together, our data suggest that atRA-mediated mesenchymal/epithelial interactions play an important role in determining the cell fate of epithelial cells via regulation of the PDX-1 gene, leading to the proper formation of the endocrine versus exocrine component during pancreatic organogenesis.

Solution structure of micelle-bound H5 peptide (427-452): a primary structure corresponding to the pore forming region of the voltage dependent potassium channel

A 26-mer peptide with the sequence of the pore forming region (residues 427-452) of the Shaker K(+) channel (H5 region) was chemically synthesized. Analyses by CD and two-dimensional 1H NMR spectroscopy were used to investigate the structure of the peptide bound to SDS micelles in solution, which are commonly used in biophysical studies. The tertiary structure of the peptide as a monomer was composed of an alpha-helix (431-438), a turn (439-442), and random coils (427-430, 443-452), and was very similar to that of the pore forming region of the native K(+) channel from Streptomyces lividans determined by X-ray analysis. This result suggests that even an isolated peptide forms a native-like conformation for residues from 431 to 442, depending on its intrinsic amino acid sequence and the surrounding environment.

Gene expression of receptors for IL-6, LIF, and CNTF in regenerating skeletal muscles

The biological actions of interleukin-6 (IL-6), leukemia inhibitory factor (LIF), and ciliary neurotrophic factor (CNTF) are mediated via respective functional receptor complexes consisting of a common signal-transducing component, gp130, and other specific receptor components, IL-6 receptor alpha (IL-6R), LIF receptor beta (LIFR), and CNTF receptor alpha (CNTFR). IL-6, LIF, and CNTF are implicated in skeletal muscle regeneration. However, the cell populations that express these receptor components in regenerating muscles are unknown. Using in situ hybridization histochemistry, we examined spatiotemporal expression patterns of gp130, IL-6R, LIFR, and CNTFR mRNAs in regenerating muscles after muscle contusion. At the early stages of regeneration (from 3 hr to Day 2 post contusion), significant signals for gp130 and LIFR mRNAs were detected in myonuclei and/or nuclei of muscle precursor cells (mpcs) and in mononuclear cells located in extracellular spaces between myofibers after muscle contusion, but IL-6R mRNA was expressed only in mononuclear cells. At Day 7 post contusion, signals for gp130, LIFR, and IL-6R mRNAs were not detected in newly formed myotubes, whereas the CNTFR mRNA level was upregulated in myotubes. These findings suggest that the upregulation of receptor subunits in distinct cell populations plays an important role in the effective regeneration of both myofibers and motor neurons. (J Histochem Cytochem 48:1203-1213, 2000)

A novel NMR method for determining the interfaces of large protein-protein complexes

Identification of the interfaces of large (Mr > 50,000) protein-protein complexes in solution by high resolution NMR has typically been achieved using experiments involving chemical shift perturbation and/or hydrogen-deuterium exchange of the main chain amide groups of the proteins. Interfaces identified using these techniques, however, are not always identical to those revealed using X-ray crystallography. In order to identify the contact residues in a large protein-protein complex more accurately, we developed a novel NMR method that uses cross-saturation phenomena in combination with TROSY detection in an optimally deuterium labeled system.

Leukemia inhibitory factor, glial cell line-derived neurotrophic factor, and their receptor expressions following muscle crush injury

Using in situ hybridization histochemistry, we characterized the spatiotemporal gene expression patterns of leukemia inhibitory factor (LIF) and glial cell line-derived neurotrophic factor (GDNF), and their receptor components (LIFR, GFR-alpha1, RET) induced in muscle cells, intramuscular nerves, and motoneurons in the regeneration processes of both muscle cells and nerves following muscle contusion. Muscle contusion induced upregulation of GDNF and GFR-alpha1 mRNAs in Schwann cell-like cells in the intramuscular nerves and of LIFR mRNA in damaged muscle cells. LIFR, GFR-alpha1, and RET mRNA expressions in motoneurons were upregulated following muscle contusion. Muscle contusion also induced more rapid, prominent transactivations of GFR-alpha1 and RET genes in motoneurons than did sciatic nerve axotomy. These findings suggest that rapid and prominent upregulation of the receptor components for LIF and GDNF in motoneurons is important for the regeneration of intramuscular motor nerves damaged by muscle contusion.