肿瘤EMT与MET是动态可逆的过程，是肿瘤细胞趋利避害、逃避药物打击、适应极端环境的自我保护机制，也是临床治疗中的棘手难题。以往针对肿瘤EMT治疗的探索收效甚微，主要由于忽视了EMT与MET的相互联系与转化。为了打破传统EMT动物模型的终点研究法的瓶颈，全面探索肿瘤EMT/MET动态转化的契机与规律，本研究将建立一系列诱导和监测系统，包括基于Tet-On的EMT/MET诱导系统；基于Cre/loxP和生物发光的EMT/MET动态监测系统；基于断裂荧光素酶生物发光的激酶活性监测系统。将这些载体合理搭配、转染、移植，构建肿瘤EMT/MET“体内诱导+实时监测”动物模型，用其探寻易于临床检验的EMT/MET标志物，筛选有效的EMT与MET抑制剂，探求两药序贯合用的数学规律和计算方法,为针对肿瘤EMT/MET动态转化的治疗策略奠定生物学、药理学与数学基础，为解决肿瘤耐药复发转移的难题提供新策略。

Tumor-associated EMT and MET are dynamic reversible processes, characterized by acquisition of stem cell-like traits, such as drug-resistance, metastasis and recurrence. Clinical anti-EMT therapy acquired limited success, although EMT determines malignant progression of cancer. The ineffective anti-EMT therapy mainly attributed to the ignorance of the relationship and dynamic transition between EMT and MET. To explore the keypoint and rule of dynamic transition between EMT and MET, we plan to establish a series of novel EMT/MET animal models that can overcome the limit of endpoint method used in traditional EMT animal models. The novel EMT/MET testing system includes: new EMT/MET inducing systems based on Tet-On vectors; new EMT/MET detecting systems based on Cre/loxP recombinase vectors and bioluminescence imaging; and new in vivo kinase activity detecting systems based on split luciferase imaging vectors. The novel EMT/MET animal models can be established by combining the above inducing and detecting system, transecting them into epithelial or mesenchymal human cancer cells, and transplanting modified cancer cells into nude mice. With the novel EMT/MET animal models, we will explore the dynamic regulation rule of EMT and MET and screen out special inhibitors. Furthermore, we will explore the mathematical law of synergistic effects of two sequentially applied drugs and establish the mathematical model to quantitatively calculate the dosage of sequential administration. In a word, this study will lay the biological, pharmacological, and mathematical foundations for the therapy against EMT and MET, and will be a new strategy to resolve the problem about cancer metastasis and recurrence.