氨基甲酰磷酸合成酶Ⅰ(CPS-I) 在原发性肝细胞癌转移过程中功能研究

Carbamoyl Phosphate Synthetase I (CPS-I) is a ligase enzyme located in the mitochondria involved in the production of urea. CPSI plays a vital role in protein and nitrogen metabolism. Recently, it’s been reported that CPS1 was down-regulated in the initiating of hepatocellular carcinoma (HCC), whereas the role of CPS1 during HCC progression and development has not been reported clearly.. This study was designed to take advantage of the large sample of HCC clinical and pathological data, combined with the cellular level and the animal level experiments, provide a new method for the clinical treatment of HCC prognosis and ideas..In our previous studies, we found the down-regulation of CPS1 in human HCC tissues and portal vein tumor thrombus. We also observed the reduced expression of CPS1 enhanced the metastasis and invasion of HCC cells. .Our project here plans :.(1)to further confirm the CPS1 as the predictive biomarker or treatment target of HCC by using a larger samples firstly;.(2)to intensively explore the role of CPS1 during the progression of HCC(especially for the modulation cell proliferation, chemoresistance, mitochondria damage, metabolism, migration and invasion);.(3)to thoroughly investigate the mechanisms involving in the CPS1 and urea cycle and their cross-talk with each other;.We expect that such information along with established clinical and demographic prognostic factors would have the potential to lead to personalized risk stratifications and interventions that could benefit the public’s health and millions of patients around the world.

氨基甲酰磷酸合成酶Ⅰ（CPS1）是尿素循环的限速酶，特异表达于肝细胞线粒体负责将游离氨转化为氨甲酰磷酸并合成代谢产物尿素。研究发现CPS1在肝癌中低表达，然而其是否参与肝癌发生发展尚无报道。我们前期工作首次发现CPS1表达水平在20例配对肝癌癌旁-原发灶-门静脉癌栓样本中逐渐降低、结合626例TCGA样本数据库发现该基因低表达与肝癌预后不良及复发转移显著相关、干扰该基因肝癌细胞转移能力明显增强。本项目拟结合临床有无门静脉癌栓的肝癌样本，首先分析CPS1表达水平与临床肝癌转移表型及预后的关系；其次从动物和细胞层面确定其对肝癌转移的影响；之后分析其是否通过影响肝细胞线粒体功能、氧化应激水平以及尿素合成代谢等调控肿瘤转移；最后通过功能获得或缺失实验明确SIRT5等CPS1互作基因在其介导的肝癌侵袭转移中的关键作用。从而阐明CPS1调控肝癌转移的分子机制，加深我们对尿素代谢与肝癌进展关系的认识。

体内大部分代谢过程均在肝脏中发生。其中，尿素循环是氨基酸代谢产生的氨通过肝脏转化为尿素的重要代谢过程。近几年多篇研究报道了尿素循环在肿瘤中的关键作用，然而其是否参与肝癌发生发展尚未有系统报道，特别是尿素循环关键酶 CPS1 在肝癌中的生物学功能也不明确。本课题组前期发现CPS1表达水平在肝癌癌旁—原发灶—门静脉癌栓样本中呈逐渐降低的趋势，结合GSE数据库中有临床随访信息的样本基因表达谱数据我们还发现 CPS1 在肝癌中的异常低表达与肝癌患者预后不良以及术后复发转移密切相关。据此，本研究详尽阐明了CPS1在肝癌转移侵袭过程中的重要作用及机制。首先，我们在体内外水平均证明CPS1缺失促进肝癌细胞增殖、转移侵袭及自我更新等恶性表型；其次，本研究对CPS1缺失促进肝癌转移的机制做了深入研究，发现CPS1低表达的肝癌细胞可通过游离氨-氧化应激（Ammonia-ROS）活化AMPK-pACC-CPT1及AMPK/mTOR信号通路，从而提高转移侵袭能力。最后，我们还发现对于CPS1缺失型的肝癌，靶向药物联合FAO抑制剂可能是合理的治疗策略。综上，本研究结果系统阐述了CPS1在肝癌转移过程中的重要作用，为肝癌的临床研究提供新思路与新靶点。