Laparoscopic cholecystectomy has rapidly been adopted by surgeons, but concerns remain about its safety, the management of common bile duct stones, and the means of appropriate training. Of 647 patients referred for cholecystectomy, preoperative endoscopic retrograde cholangiography was performed in 49 (7.6%), with 27 patients (4%) undergoing sphincterotomy and stone extraction. Traditional cholecystectomy was performed in 29 patients (4.5%). Laparoscopic cholecystectomy was attempted in 618 patients and completed successfully in 600 (97.1%). Surgical trainees functioned as the primary surgeon in 70% of cases. Technical complications occurred in three patients (0.5%), including one patient with a common bile duct laceration (0.2%). Major complications occurred in 10 patients (1.6%), with no perioperative mortality. Mean postoperative hospital stay was 1 day, with return to work or full activity a mean of 8 days after surgery. Two cases of retained common bile duct stones (0.3%) were identified. We now regard laparoscopic cholecystectomy as the "gold standard" therapy for management of symptomatic cholelithiasis.

Ribonucleotide reductase is emerging as an important determinant of gemcitabine chemoresistance in human cancers. Activity of this enzyme, which catalyses conversion of ribonucleotide 5 0 -diphosphates to their 2 0 -deoxynucleotides, is modulated by levels of its M2 subunit (RRM2). Here we show that RRM2 overexpression is associated with gemcitabine chemoresistance in pancreatic adenocarcinoma cells, and that suppression of RRM2 expression using RNA interference mediated by small interfering RNA (siRNA) enhances gemcitabine-induced cytotoxicity in vitro. We demonstrate the ability of systemically administered RRM2 siRNA to suppress tumoral RRM2 expression in an orthotopic xenograft model of pancreatic adenocarcinoma. Synergism between RRM2 siRNA and gemcitabine results in markedly suppressed tumor growth, increased tumor apoptosis and inhibition of metastasis. Our findings confirm the importance of RRM2 in pancreatic adenocarcinoma gemcitabine chemoresistance. This is the first demonstration that systemic delivery of siRNA-based therapy can enhance the efficacy of an anticancer nucleoside analog.

The EphA2 receptor tyrosine kinase is overexpressed in a variety of human cancers. We sought to characterize the role of EphA2 in pancreatic adenocarcinoma and, using RNA interference (RNAi) mediated by small interfering RNA (siRNA), we determined the effects of suppressing EphA2 expression in vitro and in vivo. EphA2 expression in PANC1, MIAPaCa2, BxPC3 and Capan2 cells was assessed by Northern and Western blot. We artificially overexpressed EphA2 by transient transfection and suppressed EphA2 expression using RNAi. Cellular invasiveness was quantified by modified Boyden chamber assay. Anoikis was induced by anchorage-independent polyHEMA culture and caspase 3 activity was quantified fluorometrically. Focal adhesion kinase (FAK) phosphorylation was assessed by immunoprecipitation. EphA2 siRNA treatment was assessed in a nude mouse xenograft model. Pancreatic adenocarcinoma cells differentially express EphA2. Inherent and induced EphA2 overexpression is associated with increased cellular invasiveness and anoikis resistance. EphA2 siRNA suppresses EphA2 expression, cellular invasiveness, anoikis resistance and FAK phosphorylation in vitro and retards tumor growth and inhibits metastasis in vivo. EphA2 is both a determinant of malignant cellular behavior and a potential therapeutic target in pancreatic adenocarcinoma.