Pancreatic cancer is a frequent malignant tumor in digestive tract with extremely poor prognosis,characterized by difficult early diagnosis,high malignancy,poor resective,limited response to chemotherapy and radiotherapy and an intense fibrotic reaction known as tumor desmoplasia.Pancreatic stellate cells play an important role in this reaction and can stimulate pancreatic cancer cells proliferation,invasion and metastasis through the interaction with pancreatic cancer cells.This review describes the role of pancreatic stellate cells in the process of pancreatic cancer progression.

Objective To investigate the effects and mechanism of IL-6 on the epithelial to mesenchymal transition of human pancreatic cancer cells.Methods IL-6 was added into the culture media of human pancreatic cancer cells Capan-2,SW1990,and STAT3-siRNA-SW1990.Cell growth was measured by MTT assays.STAT3,p-STAT3,Snail,Twist,and E-cadherin mRNA and protein expression were examined using real-time fluorescence quantitative polymerase chain reaction (RT-PCR)and Western blot,respectively.The invasion abilities of SW1990 and Capan-2 cells were determined by a cell invasion assay in vitro.Results Our results showed that 100 μg/L of IL-6 significantly promoted the growth and invasion abilities of Capan-2 and SW1990 cells (P＜0.05).The use of IL-6 not only markedly increased the protein expression of P-STAT3 and Snail,but also greatly decreased the mRNA and protein expression of E-cadherin.The use of IL-6 can not change the mRNA and protein expression of Snail and E-cadherin.Conclusion Activation of the STAT3 signal transducer pathway with IL-6 can promote the epithelial to mesenchymal transition of pancreatic cancer cells in vitro through up-regulation of Snail and down-regulation of E-cadherin expression.Therefore the STAT3 signal transducer may provide a novel therapeutic target for the treatment of pancreatic cancer.

Objective To screen the genes related with signal transducers and activators of transcription 3 (STAT3) regulating pancreatic cancer invasion and metastasis by gene chips.Methods Human pancreatic cancer cell line SW1990 stably expressing low level of Stat3 was established by lentivirus transfection,while cells transfected with mock plasmid and cells without transfection served as control groups.The differences of invasion and metastasis related genes expression among the three groups were screened by gene chips.STAT3 mRNA and protein expression was measured by real-time PCR and Western blot.Three differentially expressed genes (MMP-7,IL-1β and IgTα7) were verified.ResultsThe expression level of STAT3 mRNA was 0.391 ± 0.037 after pancreatic cancer SW1990 cell trarsfected with STAT3 targeted lentivirus,which was significantly lower than those in mock plasmid group (1.002 ± 0.015) and nontransfected group ( 1.206 ± 0.042,P ＜ 0.05 ) ; the expression level of STAT3 protein was 182.38 ± 65.32,which was significantly lower than those in mock plasmid group (223.40 ±58.40) and non-transfected group (212.33 ±53.69).Eight invasion and metastasis related genes of SW1990 lowly expressing Stat3 were upregulated,while 3 genes were down-regulated.By verification,the mRNA level of MMP-7 and IL-1β were lower than in control group transfected with mook plassmid(0.287 ± 0.115 vs 1.010 ± 0.124,t =19.45,P =0.000;0.490 ± 0.10 vs 1.002 ± 0.002,t =13.83,P =0.000),but the mRNA level of IgTα7 was not decreased (1.173 ±0.280 vs 0.998 ±0.003,t =4.236,P =0.094).Meanwhile,the protein level of MMP-7 was significantly down-regulated when Stat3 was knocked down.ConclusionsStat3 causes changes of expressions of many invasion and metastasis-related genes of SW1990,and MMP-7 may be the main target gene regulated by Stat3.

Objective To investigate the effect and mechanism of RNAi-mediated STAT3 gene silence on human pancreatic cancer cells growth in vivo. Methods STAT3 shRNA expression vector was stably transfected to SW1990 cells. STAT3 and p-STAT3 protein was examined using Western blot. The growth ability of SW1990 cells in vivo was determined in a subcutaneous tumor model of nude mice. Western blot was performed to detect the protein expression of Bcl-xL and cyclin D1. Results The protein expression of STAT3 and p-STAT3 decreased by 90% and 92% by stable transfection of STAT3 shRNA expressing vectors(P ＜0. 05). Inhibition of STAT3 with RNAi significantly inhibited the growth ability of SW1990 cells in vivo( P ＜ 0. 05 ). The tumor weight significantly decreased( P ＜ 0. 05 ). Moreover, the relative Bcl-xL and cyclinD1 protein expression in SW1990-RNAi cells reduced by 56% and 50% compared with that of the parental SW1990 cells, respectively (P ＜ 0. 05). Conclusions Inhibition of STAT3 with RNAi significantly inhibits the growth ability of pancreatic cancer cells through down-regulating Bcl-xL and cyclin D1.

Objective: In order to investigate the effects of activating and blocking Stat3 signaling pathway on invasion ability of human pancreatic cancer cells and explore its action mechanism.Methods:Human pancreatic cancer Capan-2 cells were treated with IL-6. SW1990 human pancreatic cancer cells were treated with AG490. Cell proliferation was measured by MTT assay. Western blotting and immunocytochemistry were performed to detect expression of phosphorylated Stat3 (p-Stat3) protein. Real-time fluorogentic quantitative PCR (RFQ-PCR) and Western blotting were used to detect the mRNA and protein expression of VEGF and MMP-2 mRNA, respectively. The invasion abilities of SW1990 and Capan-2 cells were determined by cell invasion assay in vitro. Results:IL-6 stimulated the proliferation of Capan-2 cells (P<0.05), elevated the expression of p-Stat3, increased the mRNA and protein expressions of vascular endothelial growth factor (VEGF) and matrix metalloproteinase 2 (MMP-2) (P<0.05), and enhanced the invasion ability of Capan-2 cells. AG490 inhibited the proliferation of SW1990 cells (P<0.05), down-regulated the expression of p-Stat3, markedly decreased the mRNA and protein expression of VEGF and MMP-2 (P<0.05), and weakened the invasion ability of SW1990 cells. Conclusion:Stat 3 signaling pathway plays an important role in the invasion and metastasis of pancreatic cancer. Stat 3 signaling transduction pathway may provide a novel therapeutic target for the treatment of pancreatic cancer.

Objective To investigate the effect of interleukin 6 (IL-6) on the growth and proliferation of human pancreatic cancer cell line Capan-2 and the signal transduction pathway. Methods MTr method was used to detect the effect of IL-6 of different concentrations on the growth and proliferation of Capan - 2 cells; cell apoptosis was detected by flow cytometry; the intracellular localization of phosphorylated STAT3 (P-STAT3) was determined by immunocytochemistry and western blot were used to detect P-STAT3, bcl-xl and Cyclin D1 in Capan-2 cells stimulated by IL-6. Results IL-6 (100 ng/ml) could remarkably promote the growth of Capan-2 cells from 1 to 4. 965 ± 0. 18 (P < 0. 05) ; the percentage of apoptosis decreased significantly from (3.21 ±0.23)% to (1.98 ±0.67)% (P <0.05) ; the expressions of P-STAT3, bcl-xl, Cyelin D1 increased significantly (P < 0.05), and the expressions of bcl-xl was positively correlated with that of P-STAT3 (r =0.985, P =0.015) ; the expressions of Cyclin DI was also positively correlated with that of P-STAT3(r=0.914,P=0.036),Conclusions IL-6 activate JAK/STAT signal transduction pathway,which played an important role in the growth and proliferation of Capan-2 cells in the presence of IL-6.

Objective To investigate the effect of RNAi-mediated sTAT3 gene silencing on the invasiveness of human pancreatic cancer cells. Methods STAT3 shRNA expression vector was stably transfected to SW1990 cells.STAT3 mRNA and protein expression were examined using reverse transcription polymerase chain reaction(RT-PCR)and Western blot,respectively.The invasion ability of SW1990 cells was determined by cell invasion assay in vitro.RT-PCR and Westem blot were performed to detect the mRNA and protein expression of the MMP-2 and VEGF,respectively. Results mRNA and protein expression of STAT3 were inhibited significantly by stable transfection of STAT3 shRNA expressing vectors.STAT3 silence with RNAi significantly inhibited the invasion ability of SW1990 cells decreasing protein and mRNA expression of MMP-2 and VEGF in SWl990 cells. Conciusion STAT3 silence with RNAi significantly inhibits the invasion ability of pancreatic cancer cells through down-regulating MMP-2 and VEGF.

Objective To investigate the expression of miRNA-301a-3p in pancreatic cancer and to correlate the expression on invasion , migration and colony formation of pancreatic cancer cells .Methods The expression of miRNA-301a-3p in 20 paired pancreatic cancer tissues and matched adjacent tissues , and pancreatic cancer cell lines and normal pancreatic ductal cells were detected by real -time PCR.miRNA-301a-3p mimics or inhibitors were used to up-regulate or down-regulate the miRNA-301a-3p level in pancre-atic cancer cell lines in order to figure out the effects of miRNA-301a-3p on cell invasion, migration and col-ony formation of pancreatic cancer cells , respectively .Results In pancreatic cancer tissues and cell lines , miRNA-301a-3p was significantly up-regulated when compared with the matched adjacent tissues ( P <0.05) and normal pancreatic ductal cells (P<0.05), respectively.Overexpression or downexpression of miRNA-301a-3p enhanced or suppressed colony formation , invasion and migration abilities of pancreatic cancer cells in vitro.Upregulation of miRNA-301a-3p promoted tumorigenesis in vivo.Conclusion miR-NA-301a-3p might function as an oncogene to promote tumorigenesis in pancreatic cancer .

Objective To investigate the expression and prognostic significance of CD151, c-Met and integrin alpha 3, alpha6 in pancreatic ductal adenocarcinoma (PDAC). Methods The expression of CD151, c-Met and integrin alpha3, alpha6 in 71 patients with PDAC and 10 samples of normal pancreas tissues were detected by immunohistochemistry, and the relationship between the expression of CD151, c-Met and integrin alpha 3, alpha 6 and the clinicopathological features, prognosis of these patients was analyzed. Results The positive expression rates of CD151, c-Met and integrin alpha 3, alpha 6 in PDAC were 81.69% (58/71) , 69.01% (49/71), 69.01% (49/71) and 84.51% (60/71) , and there was no expression in normal pancreas tissues. The expressions of CD151, c-Met were significantly associated with TNM stage and lymph node metastasis (P < 0.05). The expression of CD151 was positively correlated with the expressions of c-Met and integrin alpha3, alpha6 (r =0.583, P =0.000, r = 0.457;P =0.000, r = 0.671 ;P =0.000). Univariate analysis suggested the expression of CD151, c-Met and integrin alpha3, alpha6 was associated with survival (P<0.05). Multivariate analysis suggested the expression of CD151, c-Met was the independent prognostic factor for post-operative survival. Conclusions CD151, c-Met and integrin alpha3, alpha6 play a role in the development, metastasis and prognosis of PDAC, and they might be new markers to predict biological behavior and the prognosis of PDAC patients.

Objective To explore the application and effect of case-based learning(CBL)in vas-cular surgery clinical teaching. Methods Totally 37 resident doctors were randomly divided into 2 groups respectively: CBL teaching group (n=21)and traditional teaching group (n=16). CBL teaching was con-ducted through the following procedures:selecting typical cases-establishing and applying typical case library-autonomous learning-holding regular seminars. Traditional teaching was conducted through the following procedures: basic theory studying-participating in clinical practice-participating in case discus-sion. Evaluation was conducted based on test socre (written test and clinical operational skill test)and res-idents' feedback of teaching effect. Data were statistically described and independent sample t test was performed. Results Theoretical exam score and clinical skill test score were high in CBL group than in traditional group ((thoretical score:(85.53 ±1.75) vs. (79.94 ±2.29);clinical skill test score:(85.10±1.64)vs.(80.31±1.82)). CBL teaching group had advantages in improving learning efficiency, cultivat-ing clinical thinking,promoting mastery and application of knowledge,broadening knowledge, promoting communication and expression ability and improving study enthusiasm ,et al . Conclusion CBL teaching can effectively improve the teaching quality and obtain higher evaluation. Typical case li-brary should be constantly improved and education of vascular surgical basic theory should be strength-ened to promote CBL.