PLCE1上调TLR4/NF-κB信号通路促进食管癌侵袭与转移的分子机制

Both the Phospholipase Cε1 (PLCE1) and Toll like receptor 4(TLR4) were involved in cancer invasion and metastasis. The bioinformatics analysis indicated that there was a correlation between them. Our previous study demonstrated that PLCE1 could promote the metastasis of esophageal cancer via the NF-κB signal pathway, and the immunohistochemical staining showed that there was a positively correlation between the expression of PLCE1 and TLR4 in esophageal cancer tissue. Furthermore, the interactions between PLCE1 and TLR4 were detected with immune co-precipitation. Taken together, we speculated that PLCE1 could promote the development and progression of esophageal cancer via TLR4/NF-κB signal pathway which induce the release of inflammatory and immune molecules. To prove this hypothesis, using the modern cell and molecular biology research methods in the different aspect, such as esophageal cancer cell lines, specimens, and nude mice, we further verify the effects of the activation of TLR4/NF-κB signal pathway induced by PLCE1 on the invasion and metastasis of the esophageal cancer cell lines. Moreover, in order to illustrate the precise molecular mechanism of regulation of TLR4 molecular activity via PLCE1, we detect the effects of PLCE1 on the expression, the co-localization, binding activity, and phosphorylation level of TLR4 signal pathway related molecular such as TLR4, TRAF6, and IRF-7. Based on above results, we aim to clarify the molecular mechanism that PLCE1 promote the invasion and metastasis of esophageal cancer through regulating TLR4/NF-κB signaling pathway. Our findings may provide the potential molecular targets and new strategy for the diagnosis and treatment of esophageal cancer.

磷脂酶Cε1(PLCE1)和Toll样受体4(TLR4)均与肿瘤的侵袭转移有关，生物信息学分析表明二者存在相关性。我们前期对食管癌的研究发现，PLCE1可通过活化NF-κB分子促进食管癌的侵袭转移，PLCE1蛋白也可与TLR4蛋白结合，且二者在食管癌组织中的表达呈正相关，提示PLCE1有可能通过上调TLR4及NF-κB介导的炎性免疫分子促进食管癌的发生发展。本项目拟在食管癌细胞、组织及实验动物的不同层面，应用细胞分子生物学研究方法，在进一步证实 PLCE1通过TLR4/NF-κB通路促进食管癌细胞迁移与侵袭的基础上，系统检测PLCE1对TLR4、TRAF6及IRF-7的表达、共定位关系、结合活性及其磷酸化水平的影响，并明确PLCE1调控TLR4分子活性的确切机制，不仅有助于全面认识PLCE1通过TLR4/NF-κB促进食管癌侵袭转移的分子机制，也可能为发现新的食管癌诊疗靶点提供新的线索。

磷脂酶Cε1(PLCE1)和Toll样受体4(TLR4)均与肿瘤的侵袭转移有关。前期研究发现，二者在食管癌组织的表达呈正相关，PLCE1蛋白可与TLR4蛋白结合，而且PLCE1可上调NF-κB介导的炎性分子促进食管癌转移。本项目构建的基因敲除小鼠实验表明敲除PLCE1明显降低化学诱导的小鼠食管癌形成，在进一步从细胞、组织和动物水平证实 PLCE1介导TLR4/NF-κB通路促进食管癌侵袭转移的基础上，系统检测了PLCE1对TLR4、IRAK1及TBK1的表达、共定位关系、结合活性及其磷酸化水平的影响，明确了PLCE1通过PKCa磷酸化IRAK1上调TLR4及NF-κB介导的炎性免疫分子促进食管癌发生发展的确切机制。这些研究不仅表明PLCE1基因在食管鳞癌中发挥了癌基因的作用，还发现PLCE1可通过调控TLR4-NF-κB介导的炎性分子诱导微环境中巨噬细胞极化等改变，促进食管鳞癌细胞恶性生物学行为；由4NQO诱导形成的食管高级别瘤变和浸润癌的“肿瘤出芽”组织周围特异分布CD4+辅助性T细胞和CD8 +细胞毒性T细胞。因此，推测在食管癌变和浸润前沿“肿瘤出芽”过程中，PLCE1通过调控NF-κB介导的免疫分子诱导微环境中巨噬细胞、T细胞和中性粒细胞等相互作用，促进食管鳞癌进展，并形成特征性分子病理变化谱，但其免疫调控和具体致癌机制有待阐明，更深入的研究将为探究PLCE1相关炎性分子和免疫细胞在食管癌免疫微环境中发挥作用的机制奠定基础。