巨噬细胞在TIP30调节肝肿瘤发生过程中所起的关键作用及其机制研究

TIP30 not only regulate cell growth through multiple mechanisms, but also has a relationship with tumorigenesis and metastasis. Our previous studies revealed that knockout TIP30 in mice can lead to lung cancer and other tumors, but inhibit DEN-induced liver tumorigenesis instead of leading to liver tumor. Why TIP30 knockout can inhibite DEN-induced liver tumorigenesis and its mechanisms still remain unknown. As we know, Macrophages and its downstream NF-κB pathway is the key to tumorigenesis following liver injury and inflammation. TIP30 maybe associated with the function of Macrophages on the basis of our results that TIP30 knockout can reduce NF-κB phosphorylation in the mice liver tissue and decrease the level of serum IL-6. Our project intends to study the molecular mechanisms of inhibiting DEN-induced liver tumorigenesis by the regulation of TIP30 in the liver tissues of TIP30 knockout mice and isolated liver cells by immunoblotting, RT-qPCR, IP, etc. And then we will explore that liver macrophage infiltration, function changes of Macrophages and signal inactivation of NF-κB / IL-6 which is the key factor of inhibiting DEN-induced liver tumorigenesis by TIP30 knockout, which may contribute to find new function of TIP30 in addition to inhibiting tumour growth.

癌基因TIP30与肿瘤发生和转移相关。我们已发现Tip30基因敲除可导致小鼠肺癌等肿瘤，但不会导致肝肿瘤，反而抑制DEN诱导的小鼠肝肿瘤发生。Tip30基因敲除抑制DEN诱导的肝肿瘤发生的机理目前尚不清楚。巨噬细胞及其下游NFκB通路被认为是损伤和炎症后肝肿瘤形成的关键环节，我们已发现Tip30基因敲除可下调肝NFκB/IL-6信号活性，而EGFR下游信号活性无显著变化，考虑巨噬细胞及其下游信号通路活性改变可能在Tip30调节肝肿瘤产生的过程中起关键作用。本项目拟以Tip30基因敲除小鼠为研究对象，用免疫印迹、RT-QPCR、IP等方法，在肝组织和离体肝脏细胞中研究Tip30调控DEN诱导的肝肿瘤发生的分子机制，并探索巨噬细胞肝内浸润、巨噬细胞功能变化及NFκB/IL-6信号失活哪个环节是Tip30基因敲除抑制DEN诱导的肝肿瘤发生的关键因素，以发现TIP30抑制肿瘤生长以外的新功能。

癌基因TIP30与肿瘤发生和转移相关。我们已发现Tip30基因敲除可导致小鼠肺癌等肿瘤，但不会导致肝肿瘤，反而抑制DEN诱导的小鼠肝肿瘤发生。而巨噬细胞及其下游NFκB通路被认为是损伤和炎症后肝肿瘤形成的关键环节，我们已发现Tip30基因敲除可下调肝NFκB/IL-6信号活性，而EGFR下游信号活性无显著变化，考虑巨噬细胞及其下游信号通路活性改变可能在Tip30调节肝肿瘤产生的过程中起关键作用。本项目通过以Tip30基因敲除小鼠为研究对象，用免疫印迹、RT-QPCR、IP等方法，在肝组织和离体肝脏细胞中研究Tip30调控DEN诱导的肝肿瘤发生的分子机制，探索巨噬细胞肝内浸润、巨噬细胞功能变化及NFκB/IL-6信号失活哪个环节是Tip30基因敲除抑制DEN诱导的肝肿瘤发生的关键因素，结果发现：（1）Tip30基因敲除对DEN导致的小鼠肝细胞凋亡无明显影响；（2）Tip30基因敲除可抑制cyclinD1表达；（3）Tip30基因敲除可抑制STAT3的激活；（4）Tip30基因敲除可下调DEN处理导致的IL-6转录和翻译；（5）Tip30基因敲除可抑制DEN肝损伤诱导的巨噬细胞肝内浸润；（6）Tip30基因启动子主要在巨噬细胞中激活；（7）体外实验发现Tip30基因下调不影响巨噬细胞的迁移功能；（8）染色体免疫共沉淀发现TIP30基因与单核细胞趋化因子（MCP-1）相关，且Tip30可与SP-1基因启动子结合，这可能是导致MCP-1下调并导致巨噬细胞肝内浸润减少的原因。