细胞窖结构调控Glut-1功能参与糖酵解促胰腺癌恶性潜能的实验研究

Tumor glycolysis is an important characteristic of metastasis which is the major obstacle for the improvement in therapeutic effects of pancreatic cancer. From the view of tumor metabolism, this study aims to identify the key factors regulating the metastasis of pancreatic cancer and to assess their values as the potential effective therapeutic targets. Based on the combination of the 18F-FDG PET/CT imaging method and three dimension reconstruction technology, total lesion glycolysis (TLG) was calculated and demonstrated in our previous study to accurately and comprehensively reflect the glycolysis of pancreatic cancer. TLG was significantly associated with the metastatic features of pancreatic cancer and validated as an independent prognostic predictor for patients’ survival and recurrence. Glucose transporter 1 (Glut-1) was identified by the mechanism analysis as the key factor regulating glycolysis-mediated metastasis of pancreatic cancer. Our preliminary study further indicated that the expression of Glut-1 and its cancer-promoting activity were associated with the structure of caveolae. In this study, we will move forward to investigate the mechanism underlying the relationship between the concave structure of caveolae and the function of Glut-1 expression, and the role of their interaction in the glycolysis and metastasis of pancreatic cancer. For this purpose, we will perform cell experiments, animal experiments and clinical samples research by using experimental methods such as transmission electron microscope detection, lentivirus vectors transfection and RNA interference. By revealing the underlying mechanism, this study would provide new strategies for the treatment of metastasis of pancreatic cancer.

转移是制约胰腺癌疗效提高的瓶颈问题，糖酵解代谢是胰腺癌侵袭转移的重要特征。本研究从肿瘤代谢的角度出发，着力于寻找胰腺癌转移的关键因子，旨在为提高胰腺癌疗效提供有效靶点。本课题组前期应用PET/CT影像学手段提出糖酵解总量（TLG）能够精确地反映胰腺癌整体糖酵解代谢水平，机制分析证实葡萄糖转运蛋白1（Glut-1）是调控胰腺癌TLG的关键分子，与胰腺癌转移特征密切相关。预实验进一步提示Glut-1的促癌作用可能与细胞窖结构（参与细胞内外物质囊泡运输的关键结构）的存在有关。为阐述细胞窖内向凹陷结构对Glut-1功能的调控机制，本研究将通过透射电镜定位检测、腺病毒载体转染与RNA干扰等手段，从细胞实验、动物实验及临床研究等多方面，探讨细胞窖内向凹陷结构对Glut-1表达及功能的调控，及后者对胰腺癌细胞糖酵解及侵袭转移能力影响的分子机制。通过揭示其中的关键机制，为转移性胰腺癌的治疗提供新思路。

转移是制约胰腺癌疗效提高的瓶颈问题，糖酵解代谢是胰腺癌侵袭转移的重要特征。本研究从肿瘤代谢的角度出发，着力于寻找胰腺癌转移的关键因子，旨在为提高胰腺癌疗效提供有效靶点。本课题应用功能影像学技术（18F-FDG PET/CT），术前对胰腺癌患者进行适型三维扫描，创新性提出胰腺癌的“整体肿瘤代谢体积（MTV）”和“糖酵解总量（TLG）”更能精确地反映胰腺癌的整体糖酵解水平及恶性特征。本课题首次在胰腺癌证实肿瘤代谢负荷（MTV和TLG）优于常规病理及血清学的指标，肿瘤代谢负荷越高的胰腺癌患者术后的生存期越短、预后也越差。这提示胰腺癌生物学特征作为指导手术及术后治疗的必要性。.通过对该特征人群基因芯片的分析，发现其中一系列葡萄糖代谢相关酶出现了显著变化。通过分析糖酵解代谢相关酶与临床糖酵解代谢功能显像之间的关系，本课题证实Glut-1是糖酵解代谢显像的关键分子。研究结果进一步发现Glut-1在细胞膜上的聚集及功能执行依赖于细胞窖结构与功能的维持。Caveolin-1家族是维持细胞窖结构与功能的重要结构蛋白。本课题运用临床样本分析及体内外实验证实了Caveolin-1是调控促进胰腺癌侵袭转移的关键分子。进一步的研究发现Glut-1的表达强度及其促进胰腺癌侵袭转移的功能与Caveolin-1的表达强度之间关系密切。临床样本分析发现Glut-1的临床预后预测价值特异性地依赖于Caveolin-1的高表达，并且两者联合能够更好地预测患者的不良预后。在多种胰腺癌细胞系中，Glut-1的表达与Caveolin-1的表达呈现正向相关性，并与细胞的恶性程度呈现一致性。在体外细胞实验，上调或下调Caveolin-1的表达，显著影响了细胞窖的数目，调控Glut-1的表达，影响细胞的恶性特征。在体内动物实验亦证实了Caveolin-1表达的调控改变了Glut-1的表达及功能，并调节胰腺癌细胞侵袭与转移的能力。机制研究发现PI3K-Akt是细胞窖调节Glut-1的表达及功能的关键信号通路。因此，细胞窖的结构与功能完整性是Glut-1增强胰腺癌糖酵解促进胰腺癌侵袭转移的关键所在。