以胰腺内胰岛素为靶点治疗胰腺癌的基础研究

Pancreatic cancer has dismal prognosis. This outcome is due to that pancreatic cancer cells have high levels of aggressiveness. For instance, pancreatic cancer cells have high rates of growth, migration, and angiogenesis and also have uncontrolled glycolysis that consumes glucose, impairs energy homeostasis, and induces cancer cachexia. How pancreatic cancer cells acquire such aggressiveness is unknown. Recent studies show that high concentrations of insulin in the interstitial fluid of the pancreas may be a driving force, but the molecular mechanisms of insulin-induced stimulation on cancer cells are unclear. It appears that the insulin-induced stimulation is mediated not only by insulin receptor (IR) but also by a signaling system mastered by hypoxia-inducible factor-1α (HIF-1α). We herein hypothesize that IR, HIF-1α and a protein called coveolin-1 (cav-1) form a feed-forward loop that mediates the insulin effects on pancreatic cancer cells. In the present proposal, we seek to undertake a number of experiments to test this hypothesis. In vitro, human pancreatic cancer cells are treated with siRNA against HIF-1α or cav-1. In a separate experiment, pancreatic cancer cells are treated with the IR inhibitor PGG (penta-O-galloyl-β-D-glucose) and/or the HIF-1α inhibitor rhein. To assess effects of the interventions in vitro, we determine IR, HIF-1αand cav-1 expression and examine cell growth, glycolysis, migration and angiogenesis. In athymic mice, pancreatic cancer cells are transplanted in subcutaneous space and in the pancreas of either normal athymic mice or the athymic mice that are treated with the insulin-producing-cell toxin streptozotocin (STZ). PGG and rhein are also administered either individually or jointly in the tumor-carrying athymic mice. Our parameters in tumor graft analysis include cell growth, migration, glycolysis, angiogenesis, and intracellular signaling. In addition, we also examine in the liver, skeletal muscle and adipose tissues some enzymes that are involved in whole-body energy homeostasis. Data from this study will add greatly to the knowledge about how intra-pancreatic insulin stimulates pancreatic cancer cells. The data may provide a basis for us or others to develop new drugs for pancreatic cancer. The drugs may kill pancreatic cancer cells not only by decreasing their viability but also by decreasing their energy production through inhibition of glycolysis. Because high glycolysis in cancer cells is an etiological factor for cancer cachexia, the new drugs may also improve metabolic conditions in pancreatic cancer patients.

胰腺癌的预后极差，究其原因与胰腺癌细胞超高的恶性度有关，但后者的原因尚不清楚。我们认为胰腺间质高水平的胰岛素是原因之一，其对癌细胞的作用是通过一个由胰岛素受体（IR）、缺氧诱发因子-1α（HIF-1α）和小窝蛋白1（cav-1）组成的环路介导。为验证此假说，在体外实验中，我们用RNAi和药理学方法阻断上述环路，用分子和细胞生物学的方法检测癌细胞在信号传导、增殖、能量生成（糖酵解）等方面的变化。在随后的裸鼠实验中，我们将胰腺癌细胞接种于皮下、正常胰腺和低胰岛素胰腺（STZ裸鼠）三种环境中，用体外实验使用过的IR抑制剂五没食子酰葡萄糖（PGG）和HIF-1α抑制剂大黄酸进行治疗，研究癌细胞的生长和糖酵解情况及携瘤鼠的代谢状态。本研究将证明胰腺内胰岛素是胰腺癌治疗的重要靶点，PGG和大黄酸可通过抑制癌细胞的生长和能量生成达到抗癌的目的，并缓解携瘤者体内因癌细胞糖酵解引发的恶病质。

胰腺癌的预后极差，究其原因与胰腺癌细胞超高的恶性度有关，也与其伴发的周身代谢失衡即恶病质有关。本研究旨在阐明癌细胞超高的糖酵解率（即瓦博格效应）与癌恶病质的关系。我们认为，胰腺间质高水平的胰岛素是原因之一，其对癌细胞的作用是通过一个由胰岛素受体（IR）、缺氧诱发因子-1α（HIF-1α）和小窝蛋白1（cav-1）组成的环路而介导的。为验证此假说，在体外实验中，我们用RNAi和药理学方法阻断上述环路，用分子和细胞生物学的方法检测癌细胞在信号传导、增殖、能量生成（糖酵解）等方面的变化。在裸鼠实验中，我们将胰腺癌细胞接种于裸鼠的皮下、正常胰腺和低胰岛素胰腺（STZ鼠）三种环境中，用在体外实验使用过的IR抑制剂五没食子酰葡萄糖（PGG）、没食子儿茶素没食子酸酯（EGCG）和HIF-1α抑制剂大黄酸、大黄素进行治疗，研究癌细胞的生长和糖酵解情况及携瘤鼠的代谢状态。我们已经完全完成了标书中所计划的内容。从发表文章的独立性和完整性考虑，我们适当拓展了研究计划。现已经发表SCI论文7篇，另3篇SCI手稿已投出。我们还发表了中文论文5篇，已投出1篇。本研究证明胰腺内胰岛素是胰腺癌治疗的重要靶点，PGG、EGCG、大黄素和大黄酸可通过抑制癌细胞的生长和瓦博格效应达到抗癌的目的，并缓解携瘤者体内因癌细胞糖酵解引发的恶病质。