巨噬细胞—乳腺癌细胞融合在乳腺癌转移中的作用及机制研究

Cell fusion is a common phenomenon in tumorigenesis and tumor progression. Cell fusion and aneuploidy accompany with many types of cancer and its metastases. Epithelial mesenchymal transition (EMT) is the first step of tumor invasion and metastasis, plays a central role in tumor progression. In our previous work, we established a macrophage-breast cancer cell fusion model by electro-fusing and flow sorting in vitro. In this model we found that the migration, invasion and proliferation abilities of hybrid cells were significantly changed compared to the control of breast cancer cells. Meanwhile, it can be observed that the expression level of epithelial marker E-cadherin was significantly decreased in hybrid cells. In contrast, the level of mesenchymal marker N-cadherin was dramatically upregulated. This suggests that fusion cells may undergo the EMT transition. Proposed on the existing work, we will establish macrophage-breast cancer fusion models both in vivo and vitro, and to investigate the molecular mechanism of how the fusion regulates EMT and promotes metastasis in breast cancer. In this project, we'll further investigate if tumor cells achieve better migration ability and escape immune surveillance through changing morphology and triggering EMT by fusion with macrophages. This research will provide a new theoretical basis for clarification of the role and mechanism of cell fusion in initiation, development and biological treatment of tumor, and may have important significance in clinical application.

细胞融合是肿瘤发生和发展过程中常见的现象之一，在多类恶性肿瘤及其转移瘤中都可见肿瘤细胞融合及其引起的多倍体现象。上皮-间质转化(EMT)是肿瘤细胞侵袭、转移的首要步骤，在癌症转移进程中发挥重要作用。我们前期的工作通过细胞融合及流式分选的方法建立了巨噬细胞-乳腺癌细胞体外融合模型。在此模型下发现，融合细胞的恶性增殖能力和迁移能力都发生了明显变化。同时，上皮标志物表达下降，间质标志物表达上升，提示细胞可能发生了EMT过程。本项目拟在现有工作基础上，建立体外及体内巨噬细胞-乳腺癌融合模型，旨于研究在乳腺癌发展进程中，肿瘤细胞是否通过与巨噬细胞发生融合，改变细胞形态，诱导EMT过程，获得了更强的迁移能力及逃逸免疫监视的能力，最终影响肿瘤转移的病理特征及相关机制。为进一步明确细胞融合在肿瘤的发生、发展和生物治疗中的作用及机制提供新的理论基础，具有重要的理论和临床意义。

细胞融合是肿瘤发生和发展过程中常见的现象之一，在多类恶性肿瘤及其转移瘤中都可见肿瘤细胞融合现象。上皮-间质转化(EMT)是肿瘤细胞侵袭、转移的首要步骤，在癌症转移进程中发挥重要作用。我们通过细胞电融合及流式分选的方法建立了巨噬细胞-乳腺癌细胞体外融合模型。在此模型下发现，融合细胞的恶性增殖能力和迁移能力都发生了明显变化。同时，上皮标志物表达下降，间质标志物表达上升，snail等EMT标志物表达增多，提示细胞发生了上皮-间质转化过程。此外我们发现，细胞中MEK/ERK/HIF1α信号通路被活化，巨噬细胞—乳腺癌细胞融合能够增加肿瘤细胞对于化疗药物顺铂的耐药性。进一步通过基因芯片检测细胞基因表达水平变化发现，Tnfaip2基因在融合细胞中的表达显著增加。干涉内源Tnfaip2后，融合细胞的迁移和增殖能力都明显下降，间质标志物表达减弱而上皮标志物表达增加，说明融合细胞的EMT过程被部分逆转。本项目在乳腺癌发展进程中，研究了肿瘤细胞是否通过与巨噬细胞发生融合，改变细胞形态，诱导EMT过程，获得了更强的迁移能力及逃逸免疫监视的能力，最终影响肿瘤转移的病理特征及相关机制。为进一步明确细胞融合在肿瘤的发生、发展和生物治疗中的作用及机制提供新的理论基础，具有重要的理论和临床意义。