Nationwide epidemiological survey of early chronic pancreatitis in Japan.

BACKGROUND: The world's first diagnostic criteria for early CP were proposed in 2009 in Japan. This study aimed to clarify the clinico-epidemiological features of early CP in Japan. METHODS: Patients with early CP who were diagnosed according to the diagnostic criteria for early CP and had visited the selected hospitals in 2011 were surveyed. The study consisted of two-stage surveys: the number of patients with early CP was estimated by the first questionnaire and their clinical features were assessed by the second questionnaire. RESULTS: The estimated number of early CP patients was 5410 (95% confidence interval 3675-6945), with an overall prevalence of 4.2 per 100,000 persons. The number of patients who were newly diagnosed with early CP was estimated to be 1330 (95% confidence interval 1058-1602), with an annual incidence of 1.0 per 100,000 persons. Detailed clinical information was obtained in 151 patients in the second survey. The male-to-female sex ratio was 1.32:1. The mean age was 60.4 and the mean age at disease onset was 55.4. Idiopathic (47.7%) and alcoholic (45.0%) were the two most common etiologies. Proportions of female and idiopathic cases were higher in early CP than in definite CP. Hyperechoic foci without shadowing and stranding were the most common findings on endoscopic ultrasonography. The clinical profiles of early CP patients who showed lobularity with honeycombing on endoscopic ultrasonography or previous episodes of acute pancreatitis were similar to those of definite CP patients. CONCLUSIONS: We clarified the current status of early CP in Japan.

Prospective randomized study of endoscopic biliary stone extraction using either a basket or a balloon catheter: the BasketBall study.

BACKGROUND: In Japan and Europe, a retrieval basket is generally used for endoscopic extraction of bile duct stones, while in the US, a retrieval balloon is mainly used. However, the efficacies of these two devices have not been previously compared. Therefore, the present multicenter, prospective, randomized study was performed to compare the efficacies of these two devices for endoscopic biliary stone extraction. METHODS: This study was designed as a non-inferiority study in comparing a basket removal with a balloon removal. Six Japanese institutions participated in this study, which included 184 patients with bile duct stones <11 mm in diameter with no limitation in the number of stones. The stones were identified and measured during ERCP, after which the patients were randomly assigned to undergo endoscopic stone extraction using either a basket catheter or a balloon catheter. The primary end point was the rate of complete removals of stones within 10 min, and the secondary end point was the rate of procedure-related complications. RESULTS: There were 91 patients in the basket group and 93 in the balloon group. The rate of successful stone extraction within 10 min was 81.3 % (74/91) in the basket group and 83.9 % (78/93) in the balloon group (p = 0.7000). The complication rate was 6.6 % in the basket group and 11.8 % in the balloon group (p = 0.3092). Complications included bleeding, pancreatitis, and cholangitis. CONCLUSIONS: Basket and balloon catheters showed similar efficacies for endoscopic biliary stone extraction when stone size is 11 mm or smaller.

The significance of phosphorylated heat shock protein 27 on the prognosis of pancreatic cancer.

BACKGROUND AND AIM: The precise role of phosphorylated heat shock protein (HSP) 27 (p-HSP27) in pancreatic cancer remains to be elucidated. The aim of this study was to investigate whether the expression of p-HSP27 predicts the prognosis of patients with pancreatic cancer. METHODS: We retrospectively assessed 49 biopsied pancreatic cancer tissue samples that were obtained prior to the treatment with gemcitabine. The correlations between p-HSP27 and the clinicopathological characteristics were analyzed. RESULTS: p-HSP27 was not correlated with the response to chemotherapy or histological type. However, the median survival time was significantly longer in the patients with high p-HSP27 (275 days, n = 18) than those with low p-HSP27 (205 days, n = 31) (P = 0.0158). A multivariate Cox proportional hazards regression analysis revealed that low p-HSP27 predicted a worse prognosis. CONCLUSIONS: Higher p-HSP27 expression before chemotherapy was correlated with better survival, indicating that p-HSP27 expression could be used to predict the prognosis of pancreatic cancer.

Significance of Endoscopic Sphincterotomy Preceding Endoscopic Papillary Large Balloon Dilation in the Management of Bile Duct Stones.

BACKGROUND: Endoscopic papillary large balloon dilation (EPLBD) is safe and effective in management of common bile duct stones (CBDS). Endoscopic sphincterotomy (EST) prior to EPLBD has been performed as a standard procedure. However, the significance of EST prior to EPLBD has not been well studied yet. AIMS: To compare the clinical outcomes of EPLBD with and without EST to evaluate the significance of EST. METHODS: Between April 2010 and March 2015, a total of 82 patients with naïve papillae underwent EPLBD with or without EST for the management of CBDS. A retrospective analysis compared the efficacy and safety of EPLBD with and without EST. RESULTS: Basic patient characteristics were not significantly different between the groups that underwent EPLBD with EST (n = 27) and without EST (n = 55). Complete stone removal rates were similar between the groups (100 % in the EST group and 98 % in the non-EST group, p = 1.00). There was no significant difference in the median balloon size (13 mm in both groups, p = 0.445), rate of application of mechanical lithotripsy (26 vs. 35 % in the EST and non-EST groups, respectively, p = 0.463), or the median procedure time (38 vs. 34 min in the EST and non-EST groups, respectively, p = 0.682). The overall adverse event rates were not statistically different (4 vs. 7 % in the EST and non-EST groups, respectively, p = 1.00). Pancreatitis, cholangitis, and hemorrhage rates were also similar in both groups. CONCLUSIONS: EST prior to EPLBD may be unnecessary since this study did not demonstrate its benefits.

EUS-guided rendezvous for difficult biliary cannulation using a standardized algorithm: a multicenter prospective pilot study (with videos).

BACKGROUND AND AIMS: Biliary cannulation is necessary in therapeutic ERCP for biliary disorders. EUS-guided rendezvous (EUS-RV) can salvage failed cannulation. Our aim was to determine the safety and efficacy of EUS-RV by using a standardized algorithm with regard to the endoscope position in a prospective study. METHODS: EUS-RV was attempted after failed cannulation in 20 patients. In a standardized approach, extrahepatic bile duct (EHBD) cannulation was preferentially attempted from the second portion of the duodenum (D2) followed by additional approaches to the EHBD from the duodenal bulb (D1) or to the intrahepatic bile duct from the stomach, if necessary. A guidewire was placed in an antegrade fashion into the duodenum. After the guidewire was placed, the endoscope was exchanged for a duodenoscope to complete the cannulation. RESULTS: The bile duct was accessed from the D2 in 10 patients, but from the D1 in 5 patients and the stomach in 4 patients because of no dilation or tumor invasion at the distal EHBD. In the remaining patient, biliary puncture was not attempted due to the presence of collateral vessels. The guidewire was successfully manipulated in 80% of patients: 100% (10/10) with the D2 approach and 66.7% (6/9) with other approaches. The overall success rate was 80% (16/20). Failed EUS-RV was salvaged with a percutaneous approach in 2 patients, repeat ERCP in 1 patient, and conservative management in 1 patient. Minor adverse events occurred in 15% of patients (3/20). CONCLUSIONS: EUS-RV is a safe and effective salvage method. Using EUS-RV to approach the EHBD from the D2 may improve success rates.

Effect of a stylet on a histological specimen in EUS-guided fine-needle tissue acquisition by using 22-gauge needles: a multicenter, prospective, randomized, controlled trial.

BACKGROUND: EUS-guided FNA (EUS-FNA) has become the most efficacious way to obtain specimens from a solid lesion adjacent to the GI tract. Previous reports regarding the use of a stylet during EUS-FNA were all based on cytological diagnosis and have showed no significant superiority in terms of diagnostic yield. OBJECTIVE: To clarify the noninferiority of EUS-FNA without a stylet (S-) compared with EUS-FNA with a stylet (S+) on histological assessment. DESIGN: A prospective, single-blind, randomized, controlled crossover study. SETTING: Five tertiary referral centers in Japan. PATIENTS: Patients referred for EUS-FNA of a solid lesion. INTERVENTION: EUS-FNA S+ and S- in a total of 4 alternate passes with randomization to S+ first or S- first. MAIN OUTCOME MEASUREMENTS: The primary endpoint was the acquisition rate of an appropriate and sufficient specimen for histological assessment. The secondary endpoints were cellularity, contamination, bloodiness, diagnostic ability, and diagnostic accuracy. RESULTS: We enrolled 107 patients (110 lesions) and analyzed 220 specimens each in the S+ and S- groups. The acquisition rate of appropriate and sufficient specimens in the S+ group was 121 of 220 (55.0%) and 122 of 220 (55.5%) in the S- group. The difference in the acquisition rate of the specimen (S- minus S+) based on the generalized estimating equation was 0.42% (95% confidence interval, -6.72% to 7.56%), which was less than 10% of the prespecified noninferiority margin of this study. With regard to cellularity, contamination, bloodiness score, diagnostic ability, and diagnostic accuracy, there were no significant differences between both groups. There were no dropouts in the study. LIMITATIONS: A variety of target lesions, multiple pathologists, lack of an assessment of intraobserver and interobserver variability, and a single-blind study for the pathologists. CONCLUSION: EUS-FNA S- is noninferior to EUS-FNA S+ on histological assessment. ( CLINICAL TRIAL REGISTRATION NUMBER: UMIN000008695.).

Macroscopic on-site quality evaluation of biopsy specimens to improve the diagnostic accuracy during EUS-guided FNA using a 19-gauge needle for solid lesions: a single-center prospective pilot study (MOSE study).

BACKGROUND: Although rapid on-site cytologic evaluation provides high efficacy of EUS-guided FNA (EUS-FNA), its availability is limited. Alternatively, macroscopic on-site quality evaluation (MOSE) may increase the efficacy of EUS-FNA. OBJECTIVE: To assess the efficacy of MOSE in estimating the adequacy of histologic core specimens obtained by EUS-FNA using a standard 19-gauge needle (19GN) for solid lesions. DESIGN: A prospective pilot study. SETTING: Tertiary-care referral center. PATIENTS: One hundred patients with solid lesions (n = 111 lesions). INTERVENTIONS: EUS-FNA using 19GN MAIN OUTCOME MEASUREMENTS: The relation of a macroscopic visible core (MVC) in the FNA specimens on MOSE with histologic core and the diagnostic yields were studied. RESULTS: The feasibility of EUS-FNA using a 19GN was 99%. The final diagnoses were malignancy in 83 lesions and benign in 28. MOSE revealed MVC in 91.1% with the median length of 8 mm. Histologic core was confirmed in 78.9%. The receiver-operating characteristic curve of the length of MVC for the presence of histologic core showed the cut-off MVC length of 4 mm with area under the curve of .893. Comparisons of per-pass diagnostic yields showed significantly superior histologic, cytologic, and overall diagnostic yields in MVC ≥ 4 mm as compared with <4 mm. The multivariate analysis for false-negative pass identified lesion in the pancreas and MVC < 4 mm as significant risk factors. No adverse events were seen. LIMITATIONS: Single center, limited operators CONCLUSION: MVC of ≥4 mm on MOSE can be an indicator of specimen adequacy and can improve diagnostic yield; however, additional FNA may be recommended for pancreatic lesions. ( CLINICAL TRIAL REGISTRATION NUMBER: UMIN000010417.).

Percutaneous transgallbladder rendezvous for enteroscopic management of choledocholithiasis in patients with surgically altered anatomy.

INTRODUCTION: Endoscopic retrograde cholangiopancreatography (ERCP) in patients with surgically altered upper gastrointestinal anatomy (SAA) is generally challenging despite the use of enteroscopy. After failed biliary cannulation, rendezvous technique (RV) can be an option to assist the biliary access. However, proper needle puncture of biliary ducts, which is critical in the RV procedure, can be difficult because of insufficient biliary dilation. By contrast, the gallbladder can be punctured as a possible access route for RV. AIM: To evaluate the feasibility and safety of percutaneous transgallbladder (PTGB)-RV in patients with SAA. PATIENTS AND METHODS: Six patients who underwent PTGB-RV were included. PTGB drainage was performed in cases without sufficient biliary duct dilation. A guidewire was inserted through the PTGB route with antegrade passage through the cystic duct, common bile duct and duodenal papilla. An enteroscope was inserted up to the papilla, at the guidewire exit site. The guidewire was pulled out through the accessory channel followed by biliary cannulation over the guidewire and endoscopic papillary balloon dilation (EPBD) for stone removal. RESULTS: Six patients with SAA (Roux-en-Y in 4 and Billroth-II in 2) underwent PTGB-RV for removal of bile duct stones. In all patients, a guidewire was successfully inserted into the duodenum followed by insertion of the enteroscope and biliary cannulation. EPBD was then performed, but subsequent stone removal failed in 1 patient. Stone removal was successful in 5 patients without complication, except 1 case of mild pancreatitis. CONCLUSION: PTGB-RV seems to be a feasible and relatively safe salvage technique in patients with SAA.

Metallic stents are more efficacious than plastic stents in unresectable malignant hilar biliary strictures: a randomized controlled trial.

BACKGROUND: Endoscopic biliary stenting is a well-established palliative treatment for unresectable malignant biliary strictures, for which plastic tube stents (PSs) and self-expandable metallic stents (SEMSs) are most commonly used. The efficacy of these stents has been extensively described in distal biliary strictures, but not in hilar biliary strictures. The present study aimed to compare the efficacy of PSs and SEMSs for unresectable malignant hilar biliary strictures. METHODS: From June 2004 to November 2008, 60 patients were enrolled and prospectively randomized into the PS or SEMS group. RESULTS: The 6-month patency rate was significantly higher in the SEMS group than in the PS group (81 vs. 20%; p = 0.0012). Kaplan-Meier analysis showed significantly longer patency in the SEMS group than in the PS group (p = 0.0002); the 50% patency period was 359 days in the SEMS group and 112 days in the PS group. There was no significant difference in the overall survival period between the PS and SEMS groups (p = 0.2834). The mean number of reinterventions for stent failures was significantly lower in the SEMS group (0.63 times/patient) than in the PS group (1.80 times/patient) (p = 0.0008). The overall total cost for the treatment was significantly lower in the SEMS group than in the PS group (p = 0.0222). CONCLUSIONS: SEMSs were associated with a longer patency than PSs in patients with unresectable hilar biliary stricture. SEMSs were also more advantageous in reducing the number of reintervention sessions and the overall treatment cost.

Comparison of long-term outcomes after endoscopic sphincterotomy versus endoscopic papillary balloon dilation: a propensity score-based cohort analysis.

BACKGROUND: Endoscopic sphincterotomy (ES) is widely performed in patients with common bile duct stones (CBDS). However, the long-term outcomes of patients following ES have not been sufficiently elucidated. Impaired papillary function following ES may result in additional late complications. In contrast, endoscopic papillary balloon dilation (EPBD)-another option for treating CBDS-is expected to preserve papillary function. This study aimed to compare the long-term outcomes of patients with CBDS treated with ES to those treated with EPBD in a large cohort. In addition, a subgroup analysis was performed, according to gallbladder (GB) status. METHODS: A cohort study was performed using propensity score matching to reduce treatment selection bias. This involved the analysis of follow-up data for 1086 patients who underwent EPBD or ES for CBDS. RESULTS: Propensity score matching extracted 246 pairs of patients. The median (interquartile range) follow-up period after EPBD or ES was 93.5 (46.8-129.2) months and 90 (42-139.3) months, respectively. The incidence of CBDS recurrence after EPBD and ES were 8.5 and 15.0 %, respectively. The hazard ratio (95 % CI) was 0.577 (0.338-0.986) (P = 0.044). Based on the status of the GB, the incidence of CBDS recurrence was significantly different between post-EPBD and post-ES in the group with cholecystectomy after EPBD/ES (P = 0.013). CONCLUSIONS: The incidence of biliary complications was significantly lower in patients after EPBD than in those after ES, and this outcome appeared most markedly in patients who also underwent cholecystectomy.

Cisplatin and ultra-violet-C synergistically down-regulate receptor tyrosine kinases in human colorectal cancer cells.

BACKGROUND: Platinum-containing anti-cancer drugs such as cisplatin are widely used for patients with various types of cancers, however, resistance to cisplatin is observed in some cases. Whereas we have recently reported that high dose UV-C (200 J/m²) induces colorectal cancer cell proliferation by desensitization of EGFR, which leads oncogenic signaling in these cells, in this study we investigated the combination effect of low dose cisplatin (10 µM) and low dose UV-C (10 J/m²) on cell growth and apoptosis in several human colorectal cancer cells, SW480, DLD-1, HT29 and HCT116. RESULTS: The combination inhibited cell cycle and colony formation, while either cisplatin or UV-C alone had little effect. The combination also induced apoptosis in these cells. In addition, the combination caused the downregulation of EGFR and HER2. Moreover, UV-C alone caused the transient internalization of the EGFR, but with time EGFR recycled back to the cell surface, while cisplatin did not affect its localization. Surprisingly, the combination caused persistent internalization of the EGFR, which results in the lasting downregulation of the EGFR. CONCLUSIONS: The combination of low dose cisplatin and low dose UV-C synergistically exerted anti-cancer effect by down-regulating RTK, such as EGFR and HER2. These findings may provide a novel strategy for the treatment of patients with colorectal cancer.

Endoscopic ultrasound-guided fine needle aspiration biopsy for diagnosis of lymphoproliferative disorders: feasibility of immunohistological, flow cytometric, and cytogenetic assessments.

OBJECTIVES: In addition to morphology, immunophenotype and genetic abnormalities should be assessed during diagnosis and subclassification of lymphoproliferative disorders. The objective of this study was to evaluate the yield of endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNAB) using a standard 19-gauge needle for diagnosis and subclassification of lymphoma, assessing the feasibility of immunohistological, flow cytometric, and cytogenetic assessments. METHODS: Two hundred forty patients with suspected lymphoma were referred for EUS-FNAB to our quaternary EUS center between June 2005 and December 2010. EUS-FNAB using a conventional 19-gauge needle was attempted for all patients, followed by histological assessments including immunohistological staining, flow cytometry, and cytogenetic analysis (G-band karyotyping). Among the patients, 152 were ultimately diagnosed with lymphoma. The primary outcome measure of this study was the sensitivity of histological assessment, including immunohistological staining, flow cytometry, and G-band karyotyping, for diagnosis and subclassification of lymphoma. RESULTS: Among the 152 patients ultimately diagnosed with lymphoma, 147 patients (96.7%) were diagnosed by EUS-FNAB, and classification in accordance with the WHO (World Health Organization) system was also possible for 135 patients (88.8%) on the basis of histological findings, including immunohistological staining. Flow cytometry showed abnormal or unusual cell populations in 121 (79.6%) of the 152 patients diagnosed with lymphoma, and in 114 (90.5%) of the 126 patients diagnosed with B-cell lymphoma. Specific cytogenetic abnormalities were detected in 21 (13.8%) of the lymphoma patients. CONCLUSIONS: EUS-FNAB using a standard 19-gauge needle has high diagnostic value for lymphoma. Immunophenotyping is usually possible, while cytogenetic abnormalities can be identified in a relatively limited number of patients.

Use of samples from endoscopic ultrasound-guided 19-gauge fine-needle aspiration in diagnosis of autoimmune pancreatitis.

BACKGROUND & AIMS: Histologic techniques are used to distinguish autoimmune pancreatitis (AIP) from pancreatic malignancies and to confirm the etiology of pancreatitis. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a well-established technique used in the diagnosis of pancreatic cancer. However, it is unclear whether specimens obtained from pancreatic lesions by EUS-FNA are adequate for the histologic diagnosis of AIP, because the evaluation of tissue architecture and immunostaining assays usually require larger samples. METHODS: We evaluated samples collected by EUS-FNA with a conventional 19-gauge needle by histologic analysis, looking for features of AIP. We analyzed data from 44 patients who were diagnosed with AIP and underwent EUS-FNA with a 19-gauge needle from January 2004 to September 2010. The FNA specimens were reviewed by histologic analysis; AIP was diagnosed based on the presence of lymphoplasmacytic sclerosing pancreatitis or immunoglobulin (Ig)G4-positive plasma cells in the infiltrate. RESULTS: The specimen amount was inadequate from 3 patients. Among the remaining 41 patients, histopathologic analysis revealed lymphoplasmacytic sclerosing pancreatitis in 17 samples and IgG4-positive plasma cells in 5 (3 samples were positive for both); no samples had granulocytic epithelial lesions. Therefore, 19 patients (43%) were diagnosed with AIP based on histologic analysis. One patient had temporary abdominal pain. CONCLUSIONS: EUS-FNA, with a 19-gauge needle, is a safe and reliable procedure for obtaining pancreatic samples for the histologic analysis of AIP. Although it does not have a high diagnostic yield, it might be useful in patients without typical features of AIP because it would allow patients to avoid surgery.

Phosphorylation status of heat shock protein 27 plays a key role in gemcitabine-induced apoptosis of pancreatic cancer cells.

Gemcitabine, an antitumor drug, is currently considered to be the standard of care for the treatment of advanced pancreatic cancer, but the clinical outcome is still not satisfactory. Although heat shock protein (HSP) 27 is implicated in the resistance to chemotherapy in several types of cancers, the precise role of phosphorylated HSP27 in cancer cells remains to be clarified. In this study, we investigated the relationship between the effect of gemcitabine and the phosphorylation status of HSP27 in pancreatic cancer cells, Panc1 and KP3. Gemcitabine suppressed pancreatic cancer cell growth and induced apoptosis. Gemcitabine caused activation of p38 mitogen-activated protein kinase (MAPK), MAPK-activated protein kinase 2 (MAPKAPK-2) and subsequently phosphorylation of HSP27 at Ser15, 78 and 82 without affecting total HSP27 levels. The inhibitions of p38 MAPK and MAPKAPK-2 reduced the phosphorylation of HSP27 and apoptosis in gemcitabine-treated cells. To further investigate the role of phosphorylated HSP27, we established Panc1 cell lines which were stably transfected with empty vector (empty cells), wild-type HSP27-encoding vector (WT cells) and 2 mutant HSP27-encoding vectors that mimic non-phosphorylated (3A), and phosphorylated (3D), respectively. In comparison of empty cells with WT cells, there was no difference in cell growth rate and the sensitivity to gemcitabine. Interestingly, cell growth of 3D cells was retarded as compared to that of 3A cells. Taken together, our results strongly suggest that phosphorylation status of HSP27 plays a key role in gemcitabine-induced growth suppression of pancreatic cancer.

Ultraviolet enhances the sensitivity of pancreatic cancer cells to gemcitabine by activation of 5' AMP-activated protein kinase.

Although gemcitabine is recognized as the standard drug for the treatment of advanced pancreatic cancer, the clinical outcome is not satisfactory. We recently reported that relatively high dose ultraviolet-C (UV-C; 200J) inhibits cell growth by desensitization of epidermal growth factor receptor (EGFR) in human pancreatic cancer cells. In the present study, we investigated the combination effects of low dose UV-C (10J) and gemcitabine on apoptosis and cell growth in these cells. UV-C enhanced gemcitabine-induced suppression of cell viability. In addition, the combination use clearly induced apoptosis, while neither UV-C nor gemcitabine alone did. Concurrently, combination use caused the decrease in the EGFR protein level and reduced EGF-induced activation of Akt pathway, subsequently resulting in accumulation of ß-catenin. The order of the treatment with UV-C and gemcitabine did not affect their synergistic effects on apoptosis and cell growth. Interestingly, combination use synergistically induced phosphorylation of 5' AMP-activated protein kinase (AMPK) alpha at Thr172 and acetyl-CoA carboxylase at Ser79 as a downstream molecular target of AMPK. AMPK activator, 5-aminoimidazole-4-carboxamide-1-ß-riboside, induced apoptosis and suppressed cell growth in these cells, thus suggesting that combination effects of UV-C and gemcitabine is due to the activation of AMPK. Together, our findings could provide a new aspect of pancreatic cancer therapy.

Ultra-violet irradiation induces apoptosis via mitochondrial pathway in pancreatic cancer cells.

Pancreatic cancer is a highly lethal disease and gemcitabine is considered to be the standard of care for the treatment of advanced pancreatic cancer. However, the outcome of the patients treated with gemcitabine is still unstatisfactory and further development of new treatments is required. We recently found that short wavelength ultra-violet (UV-C) suppresses cell proliferation with downregulation of epidermal growth factor receptor (EGFR) in human pancreatic cancer cells, but not in normal pancreatic epithelial (PE) cells. In this study, we investigated the effect of UV-C on apoptosis in several cell lines derived from the pancreas. UV-C induced poly(ADP-ribose) polymerase (PARP) cleavage, which is a marker of cells undergoing apoptosis, in Panc1, MiaPaca2, KP3 and BxPC3 pancreatic cancer cells, but not in PE cells. We also observed similar effects in Hoechst 33258 staining, which shows DNA fragmentation. While p53, a tumor suppressor protein, plays a critical role in UV-C-induced cell damage, we did not observe the correlation between the sensitivity to UV-C and p53 status. Thapsigargin, an agent that promotes endoplasmic reticulum (ER) stress by depletion of lumenal calcium stores, as well as cis-diamineplatinum (II) dichloride, a classical anti-cancer drug that causes DNA damage, induced PARP cleavage even in PE cells. Moreover, UV-C-induced apoptosis in Panc1 and KP3 cells was associated with the release of cytochrome c, indicating that it was mediated via mitochondrial pathway. Taken together, UV-C has a potent anti-cancer effect on pancreatic cancer cells without adverse effect on normal cells and it could be useful for the treatment of human pancreatic cancers.

Inhibition of Rho-associated coiled-coil containing protein kinase enhances the activation of epidermal growth factor receptor in pancreatic cancer cells.

BACKGROUND: Rho-associated coiled-coil containing protein kinase (Rho-kinase/ROCK) is involved in various cellular functions including cell proliferation, and is generally considered to be oncogenic, while some studies show that ROCK functions as a negative regulator of cancer progression. As a result, the precise role of ROCK remains controversial. We have previously reported that Rho-kinase/ROCK negatively regulates epidermal growth factor (EGF)-induced cell proliferation in SW480 colon cancer cells. In the present study, we investigated the role of ROCK in EGF receptor (EGFR) signaling in the pancreatic cancer cell lines, Panc1, KP3 and AsPc1. RESULTS: In these cells, Y27632, a specific ROCK inhibitor, enhanced EGF-induced BrdU incorporation. The blockade of EGF stimulation utilizing anti-EGFR-neutralizing antibodies suppressed Panc1 cell proliferation. EGF induced RhoA activity, as well as the phosphorylation of cofilin and myosin light chain (MLC), both targets of ROCK signaling, and Y27632 suppressed both of these processes, indicating that the phosphorylation of cofilin and MLC by EGF occurs through ROCK in Panc1 cells. EGF-induced phosphorylation of EGFR at tyrosine residues was augmented when the cells were pretreated with Y27632 or were subjected to gene silencing using ROCK-siRNA. We also obtained similar results using transforming growth factor-α. In addition, EGF-induced phosphorylation of p44/p42 mitogen-activated protein kinase and Akt were also enhanced by Y27632 or ROCK-siRNA. Moreover, an immunofluorescence microscope study revealed that pretreatment with Y27632 delayed EGF-induced internalization of EGFR. Taken together, these data indicate that ROCK functions to switch off EGFR signaling by promoting the internalization of the EGFR. CONCLUSIONS: While EGF first stimulates the activation of the EGFR and subsequently increases cancer cell proliferation, EGF concurrently induces the activation of ROCK, which then turns off the activated EGFR pathway via a negative feedback system.

UVC radiation induces downregulation of EGF receptor via phosphorylation at serine 1046/1047 in human pancreatic cancer cells.

Epidermal growth factor receptor (EGFR) is overexpressed in human pancreatic cancer and is one of the clinical targets in its treatment. In the present study we investigated the mechanism underlying ultraviolet C (UVC)-radiation-induced cell growth inhibition and downregulation of EGFR in human pancreatic cancer cells (Panc1 and KP3). The cell proliferation assay indicated that Panc1 and KP3 cells were more sensitive to UVC radiation, and their growth was significantly inhibited compared to cells of the normal human pancreatic epithelial cell line, PE. Although EGFR levels was extremely low in PE cells, EGFR were highly overexpressed in Panc1 and KP3 cells, and UVC radiation downregulated the expression of EGFR in a time-dependent manner and induced phosphorylation of EGFR at Ser1046/1047 (S1046/7) in Panc1 and KP3 cells. UVC radiation induced activation of p38 mitogen-activated protein kinase (MAPK), and EGFR phosphorylation at S1046/7 induced by UVC radiation was markedly attenuated by the inhibition of p38 MAPK. Moreover, fluorescence microscopy revealed that p38 MAPK activated by UVC radiation triggered EGFR internalization and that this was not correlated with c-Cbl, an ubiquitin ligase, which plays an important role in EGF-induced EGFR downregulation. Taken together, our results suggest that in pancreatic cancer cells UVC radiation induced desensitization of the cells to EGFR stimuli via phosphorylation of EGFR at S1046/7 by activation of p38 MAPK, independent of c-Cbl.

Comparison of axial force and cell width of self-expandable metallic stents: which type of stent is better suited for hilar biliary strictures?

BACKGROUND: Various types of self-expandable metallic stents (SEMSs) are commercially available. However, few reports have compared the performance of the various SEMSs. In addition to long-term patency, maneuverability during initial placement and feasibility of re-intervention for the stent occlusion are also very important. METHODS: In this retrospective analysis, we compared the duration of stent patency and frequency of re-interventions in 96 patients diagnosed with unresectable hilar biliary strictures in whom initial 10-mm SEMSs were inserted between June 1999 and November 2008. RESULTS: Based on Kaplan-Meier curves, significantly shorter patency duration was noted for SEMSs with moderate axial force (AF) than for other groups of SEMSs with low AF. Endoscopic re-interventions for SEMS occlusion were easier in a group of SEMSs with low AF and large cell width than in other groups of SEMSs. CONCLUSIONS: With respect to patency duration and the frequency of re-intervention required, we consider that SEMSs with low AF and large cell width are favorable for hilar biliary strictures.