ABSTRACT
Objective To explore the effect of Kruppel like factor 4 (KLF4) on epithelial-to-mesenchymal transition and invasion ability of pancreatic cancer.Methods The expression of KLF4 in 70 pancreatic cancer tissues and 10 normal pancreatic tissues was detected by immunohistochemistry,and the correlations between KLF4 expression and pathological characteristics were analyzed.Small hairpin RNA targeting KLF4 (sh-KLF4) and negative control shRNA were constructed.After the transfection of shRNA,qRT-PCR and western blot were used to detect the mRNA and protein expression of KLF4,E-cadherin and vimentin,and cell scratch-wound assay and transwell assay were utilized to determine the ability of invasion and metastasis.Results KLF4 expression (47.1％) was lower in pancreatic cancer tissues compared with normal pancreatic tissues (80.0％),and negatively correlated with cell differentiation,tumor stage and distant metastasis.Down-regulated KLF4 expression in PANC1 cell caused decreased mRNA and protein expression of E-cadherin (F =25.71,P =0.0011) and increased mRNA and protein expression of vimentin (F =24.95,P=0.0012).Knockdown of KLF4 in PANC1 cell promoted the transition from epithelial morphology to mesenchymal morphology,and enhanced the healing ability (F =47.82,P ＜ 0.001),migration (F =53.68,P=0.0001) and invasion (F=27.65,P=0.0009).Conclusions Knockdown of KLF4 can promote EMT and enhance the invasion ability of pancreatic cancer.
ABSTRACT
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.