ChPF通过糖皮质激素受体信号通路调控CCL2促进胶质瘤细胞增殖作用及机制研究

Glioma was one of the most common malignant brain tumors in central nervous system. Surgery and radiochemotherapy were still the main therapies although glioma was characterized by later diagnosis, poor prognosis and low survival rate. Research shows that Chondroitin-polymerizing factor (ChPF) was reported to function as an oncogene in colorectal tumor and head and neck tumor by hypomethylation in promoter, however the concrete mechanism in cancer is still unknown. The results of our preliminary tests showed ChPF was expressed significantly higher in glioma tissues and cells. Further, high expression of ChPF indicated poor survival in glioma patients. Knocked-down ChPF expression could significantly inhibited the proliferation of U251 cell and promoted it apoptosis. Moreover, Gene expression profile microarray showed that the Glucocorticoid receptor (GR) signaling pathway was the major signaling regulated by ChPF knockdown, and the expression of CCL2 was inhibited by ChPF knockdown. At present, multiple studies have confirmed that the GR pathway may influence the progression of cancer through regulating tumor related inflammation. Accordingly, we deduced that ChPF promoted glioma progression through CCL2 regulated by glucocorticoid receptor signaling. Therefore, we plan to detect the expression of ChPF in a large cohort of glioma tissues to evaluate its clinical significance, to prove the function of ChPF in glioma and to elucidate how ChPF regulates GR signaling and the effects on inflammation response signaling pathway. And this study will provide new clue for diagnosis as well as therapy of glioma.

胶质瘤是颅内最常见的恶性肿瘤，手术合并放化疗为其主要治疗手段，但治疗效果差。多项研究表明软骨素聚合因子（ChPF）作为一致癌基因，在结直肠癌及头颈部肿瘤中呈低甲基化、高表达状态，但其对恶性肿瘤尤其对胶质瘤的影响及机制尚不清楚。我们首次研究发现，ChPF在胶质瘤组织及细胞中表达增高，ChPF高表达患者预后更差，抑制ChPF表达后细胞增殖受限、凋亡增多。为深入研究机制，进一步敲减U251细胞中ChPF表达，行基因表达谱芯片分析发现糖皮质激素受体（GR）信号通路显著被调控，同时发现炎症因子CCL2表达明显下调。目前大量文献证实GR通路可能通过调控肿瘤相关炎症反应影响着肿瘤发生、发展。综合前期试验结果及近期文献：我们推测ChPF通过GR信号调控CCL2促进胶质瘤细胞增殖。本项目拟从分子、细胞、组织以及动物水平等多层次明确ChPF促进胶质瘤增殖的具体机制，为胶质瘤靶向治疗提供新策略及依据。

软骨素聚合因子（CHPF）是参与硫酸软骨素（CS）生物合成的糖基转移酶的重要成员。我们之前的研究表明，在体外敲除CHPF可以抑制胶质瘤细胞的生长，但CHPF促进胶质瘤细胞生长的机制仍不清楚。在这项研究中，我们发现，与正常脑组织相比，CHPF在胶质瘤样本中上调，并与胶质瘤的恶性临床病理特征呈正相关。进一步研究表明，敲除CHPF可抑制胶质瘤细胞的增殖、集落形成、迁移和细胞周期。此外，CHPF的敲除也可以抑制体内胶质瘤细胞的生长。我们通过IP和LC-MS/MS技术、Co-IP和GST下拉实验来验证CHPF和MAD1L1之间的相互作用。Chip-PCR实验显示CHPF启动子区域可以与HNF4A结合，这表明HNF4A可以调节CHPF在胶质瘤细胞中的表达。