探讨间充质-上皮转化（MET）在c-Myc诱导猪成纤维细胞恶性转化中的作用及机制

c-Myc, a typical tumour gene which has an imperfect biological mechanism, participate in a variety of malignant transformation of cells. Studies have confirmed that by downregulated the expression of its target gene E-cadherin, c-Myc mediated EMT (Epithelial-mesenchymal transformation) to implement the malignant transformation of the normal human mammary epithelial cells. Our study confirmed for the first time that the enforced expression of c-Myc in pig fibroblasts triggers MET(Mesenchymal-epithelial transformation) and malignant transformation. However, the role MET played in that transformation remains unclear. Therefore we proposed that c-Myc-induced MET is required for malignant transformation of pig fibroblasts.To prove this hypothesis, First using ChIP, Western blot, Luciferase Assay experiments to verify that c-Myc is directly regulate the expression of E-cadherin. Then using the RNAi or the dominant negative mutant of E-cadherin to inhibit the expression of pig fibroblast cells E-cadherin after the c-Myc enforced expression. Analyse by blocking the up-regulation of E-cadherin, can MET be inhibit and then interrupt the process of malignant transformation. The expected results will provide a new theoretical support for the malignant transformation of fibroblast cells.

c-Myc是经典的瘤基因，参与多种细胞类型的恶性转化，但其生物学机制尚不完善。已有研究证实，c-Myc通过下调其靶基因E-cadherin(E-cad)表达诱导EMT(上皮-间充质转化)进而实现正常乳腺上皮细胞恶性转化；我们的研究首次证实，在猪成纤维细胞过表达c-Myc能够诱导MET (间充质-上皮转化)(Cell Cycle,2013)，同时诱导其恶性转化；然而，MET在成纤维细胞恶性转化过程中的作用尚不明确。基于此，我们提出c-Myc诱导的MET是猪成纤维细胞恶性转化的先决条件。为证明此假说，首先应用ChIP等方法验证在猪细胞上E-cad亦是c-Myc的靶基因；再者分别应用RNA干扰或E-cad显性负性突变体抑制过表达c-Myc后猪成纤维细胞E-cad的表达，分析阻断E-cad上调能否抑制MET并进而阻断恶性转化的发生。预期成果将为成纤维细胞的恶性转化提供新的理论支持。