Department of Internal Medicine II, Klinikum rechts der Isar, Technische Universität München, München, Germany.
German Cancer Research Center (DKFZ), Division for Cellular Immunology, Heidelberg, Germany.
Nat Med. 2014 Nov;20(11):1340-1347. doi: 10.1038/nm.3646. Epub 2014 Oct 19.
Genetically engineered mouse models (GEMMs) have dramatically improved our understanding of tumor evolution and therapeutic resistance. However, sequential genetic manipulation of gene expression and targeting of the host is almost impossible using conventional Cre-loxP-based models. We have developed an inducible dual-recombinase system by combining flippase-FRT (Flp-FRT) and Cre-loxP recombination technologies to improve GEMMs of pancreatic cancer. This enables investigation of multistep carcinogenesis, genetic manipulation of tumor subpopulations (such as cancer stem cells), selective targeting of the tumor microenvironment and genetic validation of therapeutic targets in autochthonous tumors on a genome-wide scale. As a proof of concept, we performed tumor cell-autonomous and nonautonomous targeting, recapitulated hallmarks of human multistep carcinogenesis, validated genetic therapy by 3-phosphoinositide-dependent protein kinase inactivation as well as cancer cell depletion and show that mast cells in the tumor microenvironment, which had been thought to be key oncogenic players, are dispensable for tumor formation.
基因工程小鼠模型（GEMMs）极大地提高了我们对肿瘤进化和治疗抵抗的理解。然而，使用传统的 Cre-loxP 为基础的模型，对基因表达的顺序遗传操作和对宿主的靶向几乎是不可能的。我们通过结合翻转酶-FRT（Flp-FRT）和 Cre-loxP 重组技术开发了一种诱导性双重组酶系统，以改进胰腺癌的 GEMMs。这使得能够在全基因组范围内研究多步致癌作用、肿瘤亚群（如癌症干细胞）的遗传操作、肿瘤微环境的选择性靶向以及治疗靶点的遗传验证。作为概念验证，我们进行了肿瘤细胞自主性和非自主性靶向，重现了人类多步致癌作用的标志，通过 3-磷酸肌醇依赖性蛋白激酶失活以及癌细胞耗竭验证了遗传治疗，并表明肿瘤微环境中的肥大细胞，曾被认为是关键的致癌因子，对于肿瘤形成是可有可无的。
