Background:Gemcitabine is the first-line drug for chemotherapy of pancreatic cancer. However,owing to the inherent and acquired resistance,gemcitabine does not change obviously the prognosis of patients with pancreatic cancer. Exploration of the mechanism of acquired resistance to gemcitabine is of great clinical importance. Aims:To establish a gemcitabine-resistant human pancreatic cancer cell subclone and to explore preliminarily the resistance mechanism. Methods:Human pancreatic cancer cell line SW1990 was stimulated continuously with 0. 5 μmol/ L gemcitabine in vitro to establish the gemcitabine-resistant subclone SW1990-0. 5. The resistance index of SW1990-0. 5 cells was counted by CCK-8 assay. Proliferation and invasion of SW1990 and SW1990-0. 5 cells were detected by cell doubling time assay and scratch wound healing assay in vitro;cell cycle and cell apoptosis were detected by flow cytometry;expressions of multidrug-resistance related genes(MDR-1,MRP-1,and BRCP)and gemcitabine metabolic enzyme related genes(dCK,RRM1, and RRM2)were determined by real-time PCR. Results:The resistance index of SW1990-0. 5 cells was 9. 32. Compared with the parental SW1990 cells,the proliferation capacity but not the invasion capacity of SW1990-0. 5 cells in vitro was reduced. When treated with gemcitabine,the cell cycle of SW1990-0. 5 cells was similar to that of parental cells,whereas the cell apoptosis was significantly inhibited;expressions of MRP-1,BRCP and dCK mRNA were down-regulated,while expressions of MDR-1,RRM1 and RRM2 mRNA did not change. Conclusions:A stable gemcitabine-resistant human pancreatic cancer cell subclone SW1990-0. 5 was successfully established. Inhibition of cell apoptosis and down-regulation of dCK expression might contribute to the acquired resistance to gemcitabine of pancreatic cancer.

Background:Gemcitabine is the main drug for chemotherapy of advanced pancreatic cancer,however,the prognosis of pancreatic cancer patients has not been changed obviously because of the high innate and acquired resistance of cancer cells to gemcitabine. Aims:To investigate the correlation of DNA repair and expression of human APE1 / Ref-1(apurinic/apyrimidinic endonuclease 1 / redox factor-1),the key enzyme in base excision repair pathway,with the resistance of pancreatic cancer to gemcitabine. Methods:A gemcitabine-resistant human pancreatic cancer cell line SW1990-0. 5 with a resistance index of 9. 32 and its parental cell line SW1990 were treated with gemcitabine. DNA injury was assessed by comet assay. Expressions of APE1 / Ref-1 mRNA and protein were determined by real-time PCR and Western blotting, respectively. Results:In comet assay,after treated with gemcitabine for 24 hours,OTM value of SW1990-0. 5 and SW1990 cells were 0. 32 ± 0. 13 and 26. 96 ± 6. 83,respectively. Expression level of APE1 / Ref-1 mRNA in SW1990-0. 5 cells was 2. 48 ± 0. 49;and expression levels of APE1 / Ref-1 protein in SW1990-0. 5 and SW1990 cells were 1. 57 ± 0. 08 and 0. 84 ± 0. 06,respectively. Statistically significant differences were existed in all these parameters between SW1990-0. 5 and SW1990 cells(P all < 0. 05). Conclusions:DNA repair might be correlated with the resistance of pancreatic cancer to gemcitabine,and up-regulation of APE1 / Ref-1 might contribute to this resistance by its function on DNA repair.

Objective To discuss the influence of different concentration sulindac on pancreatic cancer cell line PANC-1 cell proliferation and apoptosis,and investigate the possible mechanism that sulindac can inhibit the Wnt/beta-catenin pathway to kill pancreatic cancer cells. Methods PANC-1 cell were divided into negative control group (added containing no sulindac DMSO)and experimental group (added sulindac with concentrations of 0.25 ,0.5 ,1 ,1.5 ,2 mM medium,respectively,name as 0.25 mM group,0.5 mM group,1.0 mM group,1.5 mM group,2.0 mM group),and treated with different time,cell proliferation inhibition ratio in each group was detected by MTT assay,cell apoptosis ratio was detected by flow cytometry,the expression ofβ-catenin mRNA and protein were detected by RT-PCR and immunocytochemistry.Results MTT results showed that sulindac can inhibit the cell proliferation of PANC-1 by a dose-and time-dependent manner.Cell apoptosis increased after sulindac treatment in different degrees,and there were statistical differences between 1.5,2.0 mMgroup and control groups (P<0.05).RT-PCR results showed that the expression ofβ-catenin mRNA decreased after the treatment of sulindac,there were statistical differences between 1.5,2.0 mMgroup and control group (P<0.05). In the 2.0mM group,the expression ofβ-catenin decreased along with the time extending (P<0.05 ).ICC results showed that sulindac inhibited the expression ofβ-catenin protein and nuclear accumulation,there were no statistical differences in 0.25 ,0.5 mM group and control group,but there were statistical differences in 1.0,1.5,2.0 mMgroup.Conclusion Sulindac could inhibit cell proliferation and facilitate apoptosis of PANC-1,this effect is dose-and time-dependent.The inhibition of Wnt/beta-catenin signal pathway may be a possible mechanism of its cytotoxicity.

Objective To compare the effect of parenteral nutrition and enteral nutrition with different start time on acute pancreatitic patients.Methods Randomized controlled trials comparing enteral and parenteral nutrition in acute pancreatitic patients published from January 1996 to January 2011 were searched in MEDLINE,EMBASE,Cochrane databases,Wanfang science library,and China National Knowledge Infrastructure.The information about study design,patient characteristics,and outcomes were extracted by two independent analysers before processed with RevMan 4.2 software.Results Altogether 14 trials were included.When started after 24 hours of admission,enteral nutrition,in comparison with total parenteral nutrition,resulted in a statistically significant reduction in the risks of infections (P =0.0004),surgical intervention (P =0.0200),organ failure (P =0.0400),and morality (P =0.0002) in acute pancreatitic patient.When started within 48 hours of admission,enteral nutrition,in comparison with total parenteral nutrition,resulted in a statistically significant reduction in the risks of infections (P =0.0000),surgical intervention (P =0.0001),organ failure (P =0.0006),and mortality (P =0.0300) in acute pancreatitic patients.Conclusions The time of the commencement of nutriton has an influence on the benefits of enteral nutrition.Enteral nutrition started between 24 hours and 48 hours of admission is more effective than within 24 hours or after 48 hours of admission.

Objective To analyze the effect of total parenteral nutrition (TPN) and enteral nutrition (EN) in patients with acute pancreatitis. Methods Randomized controlled trials of TPN and EN in patients with acute pancreatitis were searched in Medline and China Biological Medicine Disk from Jan 1966 to June 2004. Eight studies were enrolled into the analysis. The detail about the trial design, characters of the subjects, results of the studies were reviewed by two independent authors and analysed by using Revman 4.2 software. Results Compared with TPN, EN was associated with a significantly lower incidence of secondary infections (RR 0.45, 95% CI 0.29-0.68, P=0.0002) and other complications(RR 0.67, 95% CI 0.47-0.96, P=0.03), fewer surgical interventions (RR 0.47, 95%CI 0.24-0.94, P=0.03) and shorter hospitalization. However, there was no significant difference in mortality (RR 0.61, 95%CI 0.32-1.18, P=0.14) between patients with TPN and EN. Conclusion EN could be the preferred nutrition feeding method in patients with acute pancreatitis.

Objective To investigate the changes of Notch signaling pathway activity in human pancreatic cancer cell lines (SW1990, BxPC3 )after gemcitabine induction, and to study its relationship with pancreatic cancer resistant to gemcitabine chemotherapy. Methods The pancreatic cancer cell lines SW1990 and BxPC3 were cultured with different concentrations of gemcitabine for 48 hours. The Notch signaling pathway receptors ( Notch1, Notch2, Notch3, Notch4), ligands (Jagged1, Jagged2) and downstream target Hesl mRNAs expression were detected by quantitative real-time PCR (Q-PCR). Protein levels of Hes1 were determined by Western blotting. Results After treatment with 2 μmol/L gemcitabine for 48 hours, the expression of Notch1, Notch2, Notch3, Jagged1, Jagged2 and Hes1 mRNAs in SW1990 cells were 8.26 ±0.48, 39.12 ±4.87, 0.84 ±0.06, 105.8 ± 17.92, 6.59 ±0.32 and 17.30 ±2.96, which were significantly elevated when compared with those without gemcitabine treatment ( 1.02 ± 0. 15, 15.25 ± 1.28, 0. 12 ± 0.02,32.66 ± 1.98, 1.88 ± 0.29 and 5.02 ± 0.64, P < 0.05 or P < 0. 01 ); the expression in BxPC3 cells was 7.87 ±0.59, 109.4 ± 10.98, 0.74 ±0.19, 62.73 ± 13.50, 2.09 ±0.16 and 15.38 ± 1.06, which were significantly elevated when compared with those without gemcitabine treatment ( 1.14 ±0.43, 58.96 ±2.63,0.10 ± 0.02, 16.95 ± 3.79, 0.98 ± 0.02 and 2.04 ± 0.16, P < 0.05 or P < 0.01 ). The expressions of Hes1protein in SW1990 cells after 1, 2 μmol/L gemcitabine treatment for 48 h were 0.30 ±0.03, 0.42 ±0.03;and the expressions in BxPC3 cells were 0.33 ± 0.02, 0.45 ± 0.03, which were significantly increased when compared with those without gemcitabine treatment (0.13 ± 0.01, F = 33.71,0.09 ± 0.02, F = 38.54, P <0.01 ). Conclusions The Notch signaling pathway is significantly activated in pancreatic cancer cells SW1990 and BxPC3 by gemcitabine, which may be one of the mechanisms of chemoresistance.

Objective To compare the value of bedside index for severity in acute pancreatitis (BISAP),Ranson score and Balthazar computed tomography severity index (CTSI) in predicting the severity and prognosis of acute pancreatitis (AP).Methods From 2005 to 2011 in Shanghai,the clinical data of 1004 AP cases from seven hospitals was collected and retrospectively analyzed.The value of BISAP score,Ranson score and Balthazar CTSI in predicting the severity and prognosis of AP were assessed with receiver operator characteristic (ROC) curve.Results Among 1004 patients,the main cause of AP was biliary disease (580 cases),about 57.77％.The incidence of pancreatic necrosis,mortality and SAP increased along with BISAP score.The risk of pancreatic necrosis in patients with CTSI ≥ three was significantly higher than that of ＜ three.The risk of pancreatic necrosis and SAP in patients with BISAP score ≥ two was significantly higher than that of ＜ two (OR:4.93,95％CI 3.62-6.70; OR 2.62,95％CI 1.59-4.31,respectively).There was no significant difference in the accuracy of predicting the progression and mortality of AP among these three score systems.However the sensitivity of BISAP score (OR:61.54,95％CI 35.09-87.99) in predicting the progression and mortality of AP was better than that of Ranson (OR:46.15,95 ％ CI 19.05-73.25) and CTSI (OR:46.15,95％CI 19.05-73.25).Conclusions BISAP score is easy to perform and when combined with CTSI,it helps to make the diagnosis and classification of AP in time,predict the prognosis accurately.Compared with Ranson score,BISAP score has higher clinical value.

Barrett’s esophagus (BE) is the recognized precancerous lesion and risk factor for esophageal adenocarcinoma (EAC), and has a high miss diagnosis rate and low survival rate when malignantly transformed into EAC, moreover, there are only limited monitoring method and treatment. Therefore, the screening of biomarkers is highly expected, especially the risk stratification biomarkers related to the progression of malignant transformation of BE. Such biomarkers can help to determine early, quickly and accurately the disease process, and guide the stratified management and precise treatment of BE, reduce the malignancy rate and mortality. This article focused on the dynamic evolutionary process of intra‑tumor heterogeneity, and reviewed the current status and challenges of research on BE biomarkers in risk stratification from the genetics, epigenetics and serology perspectives.