ABSTRACT
ObjectiveTo investigate the effects of insulin on the proliferation and invasion of human pancreatic cancer cells PANC1,and on its HIF-1α,VEGF expression.MethodsPANC1 was pretreated with insulin of different concentrations (0.1,1,10,100 nmol/L).The proliferation of PANC1 was tested by MTTmethod,and transwell assay was used to test the invasion ability of PANC1.HIF-1α,VEGF and PCNA protein expression was assessed by Western blots,and HIF-1α,VEGF mRNA was detected by real-time PCR.Results Insulin could increase the proliferation of PANC1 in a dose-dependent manner (p ＜0.05 ),and increase the expression of HIF-1α,VEGF protein.After 100 nmol/L insulin treatment for4 d,the PCNA protein expression in the insulin group was significantly higher than that in the control group (1.196 ±0.014 vs 1.157 ±0.013,P ＜ 0.05).The cancer cells passed through the chamber in insulin group were much more than that in the control group ( 141.0 ± 2.1 vs 89.0 ± 1.4,P ＜0.05 ).The expression of HIF-1α protein was significantly increased (1.139 ±0.020 vs 0.598 ±0.013,P ＜0.05),while there was no significant change of HIF-1αmRNA expression.Both the expression of VEGF protein and mRNA were significantly increased (1.011 ± 0.023 vs 0.627 ± 0.013 0.970 ± 0.016 vs 0.350 ± 0.01 3,P ＜ 0.05 ).Conclusions High insulin microenvironment could enhance the proliferation and invasion of PANC1 cells by up-regulating the expression of HIF-1α and VEGF.
ABSTRACT
Objective To investigate the effects of sodium butyrate(NaBT) on proliferation of human pancreatic cancer cell line ASPC-1 and explore the possible mechanism. Methods The methylthiazolyl tetrazolium assay (MTT) method was used to detect cell proliferation and draw a curve. The cell apoptosis and cell cycle were determined with flow cytometry. Western blot was used to study the effect NaBT on the pancreatic cancer cells and explore its mechansim. Real-time PCR was employed to assess the expression levels of p53, p21, bcl-2 and cell cycle regulation gene p21. Results After incubation with different concentrations of NaBT for 24 to 72 h, ASPC-1 cell proliferation was inhibited dramatically. NaBT induced an increase of G0/G1 phase cells and a significant decrease in the ratio of S phase cells. The expression of p21 and bax was up-regulated at protein and mRNA level. The expression of bcl-2 was down-regulated at protein and mRNA level. There was no significant difference in the expression of p53 at protein and mRNA level. Conclusion TSA-induced growth inhibition is associated with a block in the G0/G1 phase and apoptosis, which may occur through down-regulating the expression of apoptosis gene bcl-2 and up-regulating the expression of cell cycle regulation gene p21and pro-apoptotic gene bax.
ABSTRACT
This study examined whether insulin-stimulated hypoxia-inducible factor 1alpha (HIF-1alpha) expression plays a crucial role in promoting the proliferative vitality and invasive capability in human pancreatic cancer cells. PANC-1 cells were divided into three groups: Control group, insulin group and insulin+YC-1 (a pharmacological inhibitor of HIF-1alpha) group in terms of different treatments. Cells in the insulin group or insulin+YC-1 group were treated with insulin (0.1, 1, 10 and 100 nmol/L) alone or combined with 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1, 0.1, 1, 10 and 100 mumol/L). HIF-1alpha mRNA and protein expression in PANC-1 cells was determined by real-time RT-PCR and Western blotting respectively. Cell proliferation and invasion were measured by using growth curve and invasion assay, respectively. Western blot analysis demonstrated that insulin dose-dependently increased the HIF-1alpha protein expression, and YC-1 could dose-dependently block this effect. However, neither insulin nor YC-1 altered HIF-1alpha mRNA levels in PANC-1 cells. Moreover, insulin could enhance the proliferation and invasion of PANC-1 cells, while YC-1 could weaken this effect. It was concluded that the malignant proliferation and local invasion of pancreatic cancer cells may be related to high-insulin microenvironment. The tumor biological behavior change resulting from high-insulin microenvironment may be associated with the increased expression of HIF-1alpha protein.