Objective To investigate the effect and mechanism of STAT3 gene silencing on the growth of xenografts in human pancreatic cancer SW1990 cells in nude mice.Methods The expression vector inserted with shRNA targeting at STAT3 gene was constructed and was stably transfected into SW1990 cells (SW1990-RNAi group).SW1990 cells transfected with negative control shRNA expression vector (SW1990-Con group) and parent SW1990 (SW1990 group) were used as controls.STAT3,VEGF,MMP-2 protein expressions in these groups were determined by using Western blot.The subcutaneous xenografts models were established in nude mice,and the growth of xenografts was observed,CD34 expressions were determined by immunohistochemistry and MVD was measured.Results The expression of STAT3 protein was 84.69 ± 9.31,82.00 ± 7.76,7.93 ± 1.24,repectively,in SW1990 group,SW1990-Con group,SW1990-RNAi group,and the expression of VEGF protein was 82.94 ± 8.97,80.86 ± 10.28,39.04 ± 6.23,respectively,and the expression of MMP-2 protein was 40.88 ± 5.09,38.26 ± 5.71,12.54 ± 2.15,respectively.The expression in SW1990-RNAi group was significantly lower than those in other 2 groups (P ＜ 0.05),while the expression of all three proteins between SW1990-Con group and SW1990 group was not significantly different.The weight of the xenografts in SW1990 group,SW1990-Con group,SW1990-RNAi group was (2.2 ± 0.4),(2.2 ± 0.3),(0.5 ± 0.3) g,respectively ; the MVD of the xenografts was (20.35 ± 2.41),(18.79 ± 1.94),(9.62 ± 1.06) per high power field,respectively,and the number in SW1990-RNAi group was significantly lower than those in other 2 groups (P ＜ 0.05 or P ＜ 0.01),while the difference between SW1990-Con group and SW1990 group were not significant.Conclusions Inhibition of STAT3 gene expression can significantly slow the growth of SW1990 xenografts in nude mice,and the mechanism may be related with down-regulation of VEGF and MMP-2 expression and inhibition of the angiogenesis of pancreatic cancer.

Objective To study the relationship between the expression of Caveolin-1 (Cav-1) and epithelial-mesenchymal transition(EMT) or metastasis in human pancreatic cancer.Methods The Cav-1 protein and EMT markers in highly metastatic pancreatic cancer cell lines (L3.7,Panc02-H7) and poorly metastatic pancreatic cancer cell lines (COLO357,Panc02) was detected by Western blotting and immunofluorescence.The morphology of the pancreatic cancer cells were observed under phase-contrast photomicrographs.The plasmids pcDNA3.1-caveolin-1 and control vector pcDNA3.1 were transfected into COLO357 cells by Lipofectamine LTX.The expression of Cav-1 protein,E-cadherin and vimentin were detected,and the morphology of COLO357 cells observed.Results L3.7 and Panc02-H7 cells had strong positive Cav-1 staining and high expression of mesenchymal marker (vimentin,N-cadherin) and low epithelial marker (E-cadherin,β-catenin),whereas COLO357 and Panc02 cells with typical epithelial morphology were weak positive in Cav-1 staining and of low expression of vimentin,N-cadherin and high expression of E-cadherin,β-catenin.In Cav-1 transfected COLO357 cells vimentin expression increased,and E-cadherins decreased resulting in typical morphology changes of EMT.Conclusions Overexpression of caveolin-1 is correlated with epithelial-mesenchymal transition of pancreatic cancer cells and cancer metastasis.

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 .