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.

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

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 20mm 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 S­1 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 S­1 combination therapy for locally advanced pancreatic head cancer as a neoadjuvant setting. We consider that multidisciplinary treatment including gemcitabine plus S­1 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.

Contribution of 18F-fluorodeoxyglucose positron emission tomography to the diagnosis of early pancreatic carcinoma.

BACKGROUND/PURPOSE: Pancreatic carcinoma has a poor prognosis, and early detection is essential to allow potentially curative resection. Despite the wide array of diagnostic tools available, the detection of small pancreatic tumors remains difficult. The aim of this study was to investigate the contribution of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) to the diagnosis of early pancreatic cancer. METHODS: FDG-PET was performed in 56 patients with pancreatic cancer who underwent curative surgery. The standardized uptake value (SUV) for FDG was calculated in each patient and the relationships between the SUV and various clinicopathological factors were analyzed. RESULTS: The tumors ranged from 0.8 to 6.5 cm in diameter. When the cutoff value for the SUV was set at 2.5, 51 of the 56 patients (91%) had a positive FDG-PET study. The SUV did not show a significant difference in relation to tumor differentiation or pTS and pT factors. There was also no correlation between the SUV and the maximum tumor diameter (r = 0.22; P = 0.1). Five tumors had an SUV below the cutoff value, and all of these lesions had intermediate or scirrhous stroma rather than medullary stroma. CONCLUSIONS: These results indicate that FDG-PET is useful for the detection of small early pancreatic cancers.

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.

Intraductal papillary mucinous neoplasms of the pancreas: clinicopathologic characteristics and long-term follow-up after resection.

BACKGROUND: Resection is recommended for main duct intraductal papillary mucinous neoplasms (IPMNs) of the pancreas because of the high risk of malignancy, but the indications for resection of branch duct and mixed-type IPMNs remain controversial. Our objective was to determine the appropriate management of IPMNs based on clinicopathologic characteristics and survival data obtained after resection. METHODS: A total of 72 consecutive IPMN patients who underwent resection between January 1984 and June 2006 were reviewed. The lesions were classified as main duct, branch duct, or mixed-type IPMNs and histologically graded as noninvasive (adenoma, borderline neoplasm, carcinoma in situ) or invasive. RESULTS: Main duct IPMNs (n=15) were associated with a significantly worse prognosis than other subtypes. For branch duct (n=49) and mixed-type IPMNs (n=8), the diameter of the cystic lesions was an independent predictor of malignancy by multivariate analysis. However, four patients with cysts<30 mm in diameter and no mural nodules had a malignancy. No patient with noninvasive IPMN died of this disease, showing excellent survival, whereas the 5-year survival rate of patients with invasive IPMNs was only 57.6% and was significantly worse than that of patients with noninvasive IPMNs (p=0.0002). CONCLUSIONS: Resection of all main duct IPMNs seems to be reasonable. Invasive IPMNs were associated with significantly worse survival than noninvasive IPMNs. Although the diameter of cystic lesions was a predictor of malignancy for branch duct and mixed-type IPMNs, precise preoperative identification of malignancy was difficult. Therefore, these lesions should be managed by aggressive resection before invasion occurs to improve survival.

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.

[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.

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.

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.

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.

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.