The effect of dominant negative c-Jun, TAM67, on tumorigenesis of ETV6-NTRK3 transduced Eph4 cells. Mus musculus

We report a mouse model that recapitulates expression of the ETV6-NTRK3 (EN) fusion oncoprotein, the product of the t(12;15)(p13;q25) translocation characteristic of human secretory breast carcinoma. Activation of EN expression in mammary tissues by Whey acidic protein (Wap) promoter-driven Cre leads to fully penetrant, multifocal malignant breast cancer with short latency. We provide genetic evidence that committed bipotent or CD61+ luminal alveolar progenitors, are targets of tumorigenesis. Furthermore, EN transforms these otherwise transient progenitors through activation of the AP1 complex. Given increasing relevance of chromosomal translocations in epithelial cancers, such mice serve as a paradigm for the study of their genetic pathogenesis and cellular origins, and generation of novel preclinical models. We showed that forced expression of a dominant negative version of c-Jun (TAM67) in EN-transduced Eph4 mammary epithelial cells impairs their ability to form tumors in immunodeficient nude mice, thus provided validation that EN-initiated mammary tumorigenesis is largely mediated through the AP1 complex. Keywords: genetic modification, cell type comparison Overall design: To validate that EN-initiated mammary tumorigenesis is largely mediated through the AP1 complex, we generated EN-transduced Eph4 (EN-Eph4) mammary epithelial cells as well as EN-Eph4 cells co-expressing a dominant negative version of c-Jun (TAM67), and transplanted them into nude mice. We then isolated total RNAs from resulted tumors and collected their expression profiles using Affymetrix mouse MOE 430.2 chips.

本研究报道了一款可重现ETV6-NTRK3（ETV6-NTRK3, EN）融合癌蛋白表达的小鼠模型，该融合癌蛋白是人类分泌型乳腺癌特征性t(12;15)(p13;q25)染色体易位的产物。通过乳清酸性蛋白（Whey acidic protein, Wap）启动子驱动的Cre重组酶介导乳腺组织中EN的表达，可诱导完全外显、多灶性的恶性乳腺癌，且潜伏期较短。本研究提供遗传学证据表明，定型双潜能细胞或CD61+腔面肺泡祖细胞是肿瘤发生的靶细胞。进一步研究发现，EN可通过激活AP1复合物（AP1 complex），将这些本为短暂存在的祖细胞转化为肿瘤细胞。鉴于染色体易位在上皮源性癌症中的相关性日益凸显，此类小鼠可作为研究其遗传致病机制与细胞起源、构建新型临床前模型的范式。本研究证实，在EN转导的Eph4乳腺上皮细胞中强制表达c-Jun的显性负性突变体（TAM67），会削弱其在免疫缺陷裸鼠体内的成瘤能力，从而验证了EN诱导的乳腺肿瘤发生主要通过AP1复合物介导。关键词：基因修饰、细胞类型比较 实验设计：为验证EN诱导的乳腺肿瘤发生主要通过AP1复合物介导，本研究构建了EN转导的Eph4（EN-Eph4）乳腺上皮细胞，以及共表达c-Jun显性负性突变体（TAM67）的EN-Eph4细胞，并将其移植至裸鼠体内。随后从形成的肿瘤中分离总RNA，通过Affymetrix小鼠MOE 430.2芯片获取其表达谱数据。