PID1基因介导胰岛素抵抗环境下肿瘤发生的机制及药物靶点研究

Diabetes, especially insulin resistance, increases the risk of tumor development. Insulin not only promotes neoplasia via insulin receptors on epithelial tissue directly, but also accelerates cancinogenesis by insulin growth factor, ectopic hormone and inflammatory factors indirectly. We previously reported that the gene named PID1, which can abet insulin resistance, was found highly expressed in pancreatic cancer cells. It is extremely possible that PID1, a gene involved in cell proliferation, immunoregulation and insulin sensitive signal pathway, may exert as the key regulator for the elevated cancer risk under insulin resistance. Hence, with the application of receptor protein chip, liquid chromatography tandem mass spectrometry and computer arithmetics, we are intend to explore the upstream and downstream molecules and receptor of PID1 in clinical samples and pivotal cells related to glycometabolism, immune cells and cancer stem cells, respectively. Then we plan to detect how the signal pathway of PID1 impacts the differentiation and proliferation of cancer cells and tumorigenesis in the high insulin or high glucose environment in vitro by three-dimensional cell culture. Afterwards, we are going to study the regulation mode of PID1 on tumorigenesis, immune and metabolic microenvironment, by establishing the oncogenesis murine model based on insulin resistance in vivo. Besides, we are aim to identify the possibility of PID1 as the target for finding active compounds with both anti-insulin resistant and anti-cancer effects by studying the pharmacological action and mechanism of the active compound.

糖尿病尤其是胰岛素抵抗可增加罹患肿瘤的风险性。胰岛素可与上皮组织胰岛素受体结合直接促进肿瘤形成，还可通过胰岛素样生长因子、异位激素和炎症因子等间接促发肿瘤形成。我们前期工作发现PID1基因既在胰岛素抵抗中发挥作用又在胰腺癌细胞中高表达。基于PID1连接的细胞增殖、免疫调控和胰岛素敏感性信号通路很可能关联糖尿病胰岛素抵抗与肿瘤形成，我们拟通过受体蛋白质芯片技术，液质联用和计算机运算分析临床样本、糖代谢关键细胞、免疫细胞和肿瘤细胞中PID1上下游作用分子及其结合蛋白；通过3D细胞培养研究高胰岛素或高糖环境下PID1及其通路在肿瘤干细胞分化、增殖和肿瘤形成方面所起的关键作用；最终通过建立体内胰岛素抵抗背景下肿瘤形成模型，研究PID1对肿瘤发生及免疫微环境和代谢微环境的调控方式，研究活性化合物的药理作用与机制，以确定靶向PID1调控通路发挥抗胰岛素抵抗和抗肿瘤作用的可能性。

PID1基因作为一个肥胖相关基因既参与胰岛素抵抗又在胰腺癌细胞中高表达。由此PID1基因很可能促进胰岛素抵抗环境下的肿瘤发生。我们按计划构建了多种模型，探究了PID1在胰岛素抵抗以及肿瘤发生中的作用及机制。.我们通过肝脏特异性高表达PID1的小鼠和PID1敲低后肝癌发生、发展变化，确定PID1诱导肝癌发生的作用。肿瘤形成中，CD3+, CD4+和CD8+T 细胞减少, DCs细胞的成熟降低,而MDSC、Treg数量增加。PID1过表达还能降低促炎因子IL6、MCP-1等的表达及分泌。敲低PID1则促进抗肿瘤免疫。由此确定PID1的抑制抗肿瘤免疫作用。我们发现PID1高表达明显促进MDSC招募至病灶组织，且显著抑制T细胞增殖。质谱分析显示PID1 可与 ARG1结合，采用ARG1抑制剂可反转PID1过表达所致的CD4+和CD8+T 细胞减少现象，并降低MDSC、Treg数量，研究确定PID1作用于ARG1促进MDSC分化的肿瘤免疫抑制机制。.我们发现PID1过表达可促进肿瘤生长以及肿瘤细胞的糖酵解。通过液质联用和Co-IP确定PID1直接作用于肿瘤细胞中的EGFR，激活下游通路，促进肝癌的发生和发展。我们还发现干扰PID1能改善肥胖小鼠的糖耐量以及胰岛素耐量，改善小鼠的胰岛素抵抗和高胰岛素血症，PID1过表达能抑制PI3K/Akt通路。研究发现PID1下调降低脂肪组织中脂肪酸结合蛋白FABP4的表达。初步确定PID1促进胰岛素抵抗相关癌变的机制。最后我们发现，肿瘤发生中PID1的高表达与其启动子区域存在组蛋白甲基化修饰有关。.综上所述，我们的研究阐明PID1基因在胰岛素抵抗和肿瘤的发生中发挥着重要的作用，其作用机制与其抑制肿瘤免疫，导致机体异常糖、脂代谢，增强肿瘤细胞糖酵解和增殖有关，研究为治疗胰岛素抵抗和肿瘤发生提供潜在靶点和治疗方式。