表遗传调控miR-491抑制mot-2在咖啡酸及其衍生物抗肝癌血管生成中的作用

Dietary prevention and treatment of cancer has been received more and more attention; Hepatocellular carcinoma (HCC) is one of the major public health issue in our country; The angiogenesis plays a key role in the initiation and development of HCC; So the dietary anti-angiogenesis has become a new strategy in the prevention and treatment of HCC. Caffeic acid (CaA) and its derivatives (CADs) are the important components of the diet. Here, based on our previous studies and on the researches worldwide, we suggest a new mechanism underlying the anti-angiogenesis induced by CaA and CADs. CaA and CADs elevate the expression of miR-491 by inducing the DNA demethylation, which targets and decreases the expression of mot-2. Mot-2 is an up-stream regulator of JNKs/HIF-1α signal pathway. Blocking of mot-2 causes an inactivation of JNKs/HIF-1α signal pathway, which attenuates the secretion of VEGF, and inhibits the angiogenesis of HCC cells. This project intends to perform the work in the cell model, animal model, as well as in the population. Meanwhile, we will also clarify the significance of the serum miR-491, mot-2 and VEGF in HCC prognosis. By understanding a new mechanism by which CaA and CADs block the angiogenesis of HCC, this project will expand our knowledge in the molecular mechanisms underlying the anti-tumor effects induced by CaA and CADs. Moreover, the project will also help to look for the new HCC dietary intervention targets, as well as to provide new ideas in the discovery of new prognostic indicators.

膳食营养对恶性肿瘤的防治作用已日益受到关注，肝癌是我国当前社会重大公共卫生问题之一，血管生成是肝癌发生发展的根源，因此应用膳食营养抑制血管生成对肝癌的防治具有极其重要的意义。本项目根据前期工作积累，结合国内外文献报道，提出膳食中重要成分咖啡酸（CaA）及其衍生物抗肝癌血管生成的分子机制假说如下：CaA及其衍生物通过DNA去甲基化作用激活miR-491；miR-491靶向抑制mot-2而导致其下游JNKs/HIF-1α信号通路失活，阻滞肝癌细胞分泌VEGF，最终抑制肝癌细胞的血管生成能力。本项目拟从细胞、动物及人群水平系统地探讨上述分子过程在CaA及其衍生物抗肝癌血管生成中的作用机制，并进一步阐明血清miR-491、mot-2和VEGF在肝癌预后评估中的意义。为深入研究CaA及其衍生物抗肿瘤作用的分子机制、寻找肝癌的膳食干预靶标，及发现新的预后指标提供新思路。

膳食营养对恶性肿瘤的防/治作用已日益受到关注，肝癌是我国当前社会重大公共卫生问题之一，血管生成是肝癌发生发展的根源，因此应用膳食营养抑制血管生成对肝癌的防治具有极其重要的意义。本项目从细胞、动物及人群水平系统地探讨了我们提出的科学假说：CaA及其衍生物通过DNA去甲基化激活miR-491，靶向抑制mot-2导致其下游JNKs/HIF-1α信号通路失活，阻滞肝癌细胞分泌VEGF，最终抑制肝癌细胞血管生成能力。项目严格按照申请书中预定研究目标开展实验工作并就研究过程中发现的新问题开展拓展研究，主要研究结果和研究结论如下：.1. CaA可显著抑制肝癌细胞VEGF表达分泌水平、抑制肝癌细胞促血管生成能力；.2. CaA可显著上调HIF-1α泛素化水平、抑制HIF-1α/STAT-3转录复合物水平，继而抑制其与VEGF启动子结合；.3. CaA可显著抑制JNK1磷酸化水平，且该过程可能参与了其对HIF-1α泛素化调控作用；.4. Mot-2与肝癌血管生成呈正相关，且可维持肝癌细胞的促血管生成能力；.5. Mot-2启动子区存在NF-κB和缺氧反应元件，一方面：CaA可通过抑制HIF-1α或通过DNA去甲基化作用激活miR-124靶向抑制NF-κB，进而转录抑制mot-2；另一方面：CaA可通过DNA去甲基化作用激活miR-491，进而在转录后水平靶向抑制mot-2；.6. CaA可通过与mot-2直接结合，诱导其泛素化降解，继而抑制其表达及功能；.7. CaA可通过DNA去甲基化作用激活miR-148a，靶向抑制SMAD2进而抑制肝癌细胞的肿瘤干细胞样特性（自我更新能力）；.8. 发现了新的促肝癌血管生成因子14-3-3η；.9. 发现ERK和NRF2参与了CaA及其衍生物的抗氧化/抗炎作用。.本研究为继续深入系统研究CaA及其衍生物抗肿瘤作用的分子机制、寻找肝癌的膳食干预靶标，及发现新的预后评价指标提供了新思路。