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目的 探讨胰岛素对胰腺癌细胞株ASPC-1中缺氧诱导因子1α(hypoxia-inducible factor-1α,HIF-1α)表达的影响.方法 将ASPC-1细胞分为5组:常氧组,常氧加胰岛素组,缺氧组,同一缺氧时间不同胰岛素浓度组以及相同胰岛素浓度不同缺氧时间组,实时定量PCR检测HIF-1α基因表达,免疫细胞化学与Western blot检测HIF-1α蛋白表达水平的变化.Transwell实验检测加入胰岛素后肿瘤细胞侵袭能力的变化.结果 常氧下ASPC-1细胞即有一定水平HIF-1α表达,加入胰岛素刺激后HIF-1α蛋白表达随着胰岛素浓度的升高和作用时间的延长而逐渐升高,与对照组相比差异有统计学意义(P＜0.05);缺氧条件下HIF-1α表达较常氧时升高(P＜0.05);相同缺氧时间使用不同浓度胰岛素刺激时,高浓度胰岛素刺激下HIF-1α的表达较单纯缺氧更高(P＜0.05),低浓度胰岛素对HIF-1α无明显作用(P＞0.05);使用相同胰岛素处理后再进行缺氧处理,随着时间延长HIF-1α的表达先升高后下降,但各处理组较对照组差异均有统计学意义(P＜0.05).Transwell实验显示胰岛素可增强胰腺癌细胞的侵袭能力(P＜0.05).结论 胰岛素可上调胰腺癌细胞ASPC-1中HIF-1蛋白表达,并且这种作用具有一定的剂量依赖性和时间依赖性.胰岛素还可以增加ASPC-1的侵袭能力.

Objective To investigate the effect of insulin on the expression of hypoxia-inducible factor-1α in human pancreatic cancer cell line ASPC-1. Methods We divided ASPC-1 cells into five groups: normoxia; normoxia stimulated with insulin; hypoxia; hypoxia pretreated with different concentration of insulin; hypoxia of different time points pretreated with same concentration of insulin. Real-time PCR was used to test the expression of HIF-1α mRNA. Immunohistochemistry was used to examine the expression of HIF-1α in ASPC-1 of insulin treated cancer cells. Western blot was used to determine the expression of HIF-1 α protein in those cells. Transwell was used to test whether insulin could enhance the invasion ability of ASPC-1 pancreatic cancer cells. Results Insulin promotes HIF-1α protein expression. ASPC-1 cells expressed low levels of HIF-1α protein under normoxic condition. After stimulated with insulin, the expression of HIF-1 α protein significantly increased (P ＜ 0. 05 ). After treated with hypoxia, the expression of HIF-1α protein also increased(P ＜ 0. 05 ). Low concentrations of insulin didn't increase the expression of HIF-1α under hypoxic environment ( P ＞ 0. 05 ), while high concentration of insulin could increase its expression(P ＜ 0. 05). When ASPC-1 cells pretreated with insulin suffered from hypoxia, the expression of HIF-1α first increased then decreased moderately( P ＜0. 05). Insulin could enhance the invasion ability of pancreatic cancer cells( P ＜ 0. 05 ). Conclusions Insulin mediates the expression of HIF-1α protein in human pancreatic cancer ASPC-1 cells with the characteristics of dose and time dependency. Insulin could enhance the invasion ability of ASPC-1 cells.