CD147在卵巢癌细胞糖酵解过程中的作用及机制研究

Cancer cells exhibit aberrant glucose metabolism, which plays important roles in tumorigenesis and progression. The molecular mechanisms underlying aberrant glucose metabolism of cancer cells are complex and become a hot field in cancer research. Previous studies showed that CD147 was highly expressed in most cancer cells. Furthermore, CD147 facilitated the cell surface expression of MCT1 and lactate export in hepatocellular carcinoma cells, which led to the activation of PI3K/Akt pathway and thus increased p53 degradation. Our results showed that CD147 was a crucial regulator of glucose metabolism in ovarian cancer cells, and inhibition of CD147 by specific siRNA markedly reduced the expression of p-Akt and FoxM1. Our results also showed that FoxM1 activated GLUT1 transcription by direct interaction with the domain that was located in the proximal promoter of the GLUT1 gene. Our hypothesis is that CD147 can regulate FoxM1 expression by PI3K/Akt and p53-independent signaling in ovarian cancer cells. In order to further understand mechanisms of glucose metabolism in ovarian cancer cells, we will generate p53-knockout ovarian cell lines. We will further confirm the effects of CD147 on glucose metabolism by in vitro and in vivo experiments. This project is helpful for deeply investigating abnormal energy metabolism of ovarian cancer and possibly provide new drug targets and therapeutic strategy clues.

糖代谢异常是肿瘤细胞的重要特征，在肿瘤发生及进展中具有关键作用，其调控机制的研究是肿瘤领域的热点问题。既往文献和我们最近发表的研究证明，CD147在肿瘤细胞中普遍高表达，并可通过调控MCT1的膜定位与表达促进肝癌细胞乳酸分泌，激活PI3K/Akt信号通路，下调p53的表达，进而发挥促进肝癌细胞糖酵解的功能。我们最近发现CD147在卵巢癌细胞中也具有促进糖酵解的功能，干涉其表达后，p-Akt与转录因子FoxM1的表达也随之下降，且GLUT1启动子区域存在FoxM1的结合位点。我们推测在卵巢癌细胞中存在CD147-Akt-FoxM1的顺序调节，且该途径不依赖于p53。本课题拟在此基础上，构建p53基因敲除细胞，深入研究CD147参与卵巢癌细胞葡萄糖代谢的作用及分子网络调控机制。这些研究可进一步加深对卵巢癌能量代谢异常的理解，也为CD147作为卵巢癌治疗靶点提供更为丰富的分子理论基础。

本课题借助p53缺失型卵巢癌细胞系，深入研究CD147参与卵巢癌细胞糖代谢重编程的生物学作用，系统分析CD147通过非依赖p53途径促进卵巢癌细胞有氧糖酵解的分子网络调控机制。.第一部分：CD147通过非依赖p53途径促进卵巢癌细胞糖酵解的作用研究.为阐明CD147在卵巢癌细胞糖代谢过程中的作用，我们构建了稳定干涉CD147的卵巢癌细胞系。我们发现在p53野生型和缺失型的卵巢癌细胞中，干涉CD147的表达均会降低细胞糖摄取、糖酵解速率和乳酸排出，而氧消耗则有所升高。小动物PET/CT成像系统显示干涉CD147的表达会显著降低裸鼠移植瘤的18F-FDG摄取能力，且移植瘤的细胞增殖速度有所降低。总之，我们的实验结果表明CD147具有促进卵巢癌细胞糖酵解的作用，并有可能成为基于能量代谢失调的靶点。.第二部分：CD147在卵巢癌细胞中调控FoxM1的机制研究.为明确CD147促进卵巢癌细胞糖酵解的分子机制，我们使用shRNA技术在卵巢癌细胞A2780和SKOV3中干涉了CD147的表达。Western blot结果显示，在卵巢癌细胞A2780和SKOV3中下调CD147会明显降低CD147, pAKT、 pSTAT3和FoxM1的表达。Real time PCR结果显示，在卵巢癌细胞中下调CD147会明显降低FoxM1 mRNA的表达水平。AKT抑制剂LY294002和STAT3抑制剂S3I-201在卵巢癌细胞中会显著降低过表达CD147对FoxM1的上调作用。我们还发现CD147和CD44在卵巢癌细胞中共定位。通过免疫组织化学染色检测，我们发现CD147、pAKT、pSTAT3和FoxM1在卵巢癌组织中共表达，且与卵巢癌患者FIGO分期和淋巴结转移相关。.第三部分：转录因子FoxM1促进卵巢癌细胞糖代谢重编程的机制研究.我们首先筛选了转录因子FoxM1可能调控的糖酵解关键酶，在卵巢癌细胞中干涉FoxM1的表达后，发现GLUT1和HK2的表达水平也随之下降，且细胞糖酵解和增殖明显受到抑制。进一步研究发现，GLUT1和HK2的DNA启动子序列存在转录因子FoxM1的结合位点，FoxM1能在卵巢癌细胞中激活GLUT1和HK2的转录与表达。我们还发现FoxM1、GLUT1和HK2在卵巢癌组织中的表达水平远高于正常卵巢组织，且FoxM1的表达分别与GLUT1和HK2的表达正相关。