Cellular prion protein (PrPc) is a glycosylphosphatidylinositol‐anchored membrane protein that has various physical functions, including protection against apoptotic and oxidative stress, cellular uptake of copper ions, transmembrane signaling, and adhesion to the extracellular matrix. In this study, we show that PrPc is highly expressed in colorectal adenocarcinomas. Transcriptome profiling of PrPc‐depleted DLD‐1 cells revealed downregulation of glucose transporter 1 (Glut1). PrPc is shown to be involved in regulating Glut1 expression through the Fyn‐HIF‐2α pathway. As Glut1 is the natural transporter of glucose and is required for the high glycolytic rate seen in colorectal tumors, silencing of PrPc reduced the proliferation and survival rate of colorectal cancer cells in vitro. In vivo, knockdown of PrPc by hydrodynamic injection with a cocktail of PrPc–shRNA‐encoding plasmids also inhibited tumorigenicity in a xenograft model in nude mice. In summary, our data characterize a novel molecular mechanism that links PrPc expression to the regulation of glycolysis. Targeting PrPc will therefore be a promising strategy to overcome the growth and survival advantage in colorectal tumors. (Cancer Sci 2011; 102: 400–406)
BACKGROUND:The objectives of this study were to identify and validate the diagnostic value of N-glycan markers in colorectal cancer (CRC) and to uncover their underlying molecular mechanism. METHODS: In total, 347 individuals, including patients with CRC, patients with colorectal adenoma, and healthy controls, were divided randomly into a training group (n ¼ 287) and retrospective validation groups (n ¼ 60). Serum N-glycan profiling was analyzed by DNA sequencer-assisted/flurophore-assisted carbohydrate electrophoresis (DSA-FACE). Two diagnostic models were constructed based on N-glycan profiling with logistic stepwise regression. The diagnostic performance of each model was assessed further in retrospective, prospective (n ¼ 43), and follow-up (n ¼ 46) cohorts. Lectin blot and reverse transcriptase-polymerase chain reaction were used to analyze the total core-fucosylated residues and molecular expression involved in core-fucosylation modifications in CRC. RESULTS: Two diagnostic models designated CRCglycoA and CRCglycoB were constructed to differentiate CRC from normal and adenoma, respectively. The areas under the receiver operating characteristic curves (AUC) of both CRCglycoA and CRCglycoB were higher than the AUC of carcinoembryonic antigen (CEA) (CRCglycoA, 0.92 vs 0.81; CRCglycoB, 0.81 vs 0.73). The sensitivity and accuracy of CRCglycoA improved from 21.7% to 25% and from 11.63% to 18% in the training cohort, the retrospective cohort, and the prospective cohorts compared with the sensitivity and accuracy of CEA. The sensitivity of CRCglycoB improved from 20% to 28.23%. Both altered N-glycans, and results from the diagnostic models were reversed after curative surgery. The level of total core fucose residues and fucosyltransferase were decreased significantly in CRC. CONCLU-SIONS: The current results indicated that the N-glycan markers based diagnostic models are new, valuable, noninvasive alternatives for identifying CRC. The authors concluded that decreased fucosyltransferase may be responsible for decreased levels of total core-fucosylated modification in both tissues and serum from patients with CRC. Cancer 2012;118:639
Background: The use of somatostatin analogues (SAs) following pancreaticoduodenectomy (PD) is controversial. Method: Literature databases were searched systematically for relevant articles. A meta-analysis of all randomized controlled trials (RCTs) evaluating prophylactic SAs in PD was performed. Results: Fifteen RCTs involving 1,352 patients were included. There was a towards reduced incidences of pancreatic fistulas (p = 0.26), clinically significant pancreatic fistulas (p = 0.08), and bleeding (p = 0.05) in prophylactic SAs group. In subgroup analyses, prophylactic somatostatin significantly reduced the incidence of pancreatic fistulas (p = 0.02), with a nonsignificant trend toward reduced incidence of clinically significantly pancreatic fistulas (p = 0.06). Pasireotide significantly reduced the incidence of clinically significantly pancreatic fistulas (p = 0.03). Octreotide had no influence on the incidence of pancreatic fistulas. Conclusion: The current best evidence suggests prophylactic treatment with somatostatin or pasireotide has a potential role in reducing the incidence of pancreatic fistulas, while octreotide had no influence on the incidence of pancreatic fistulas. High-quality RCTs assessing the role of somatostatin and pasireotide are required for further verification.
Our results suggested that CTLA-4 +49A>G polymorphism was associated with an increased risk of colorectal cancer, but this polymorphism did not play an important role in the progression of CRC in Chinese.
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