Ochiai Masako, Yoshihara Yasunori, Maru Yoshiaki, Matsuura Tetsuya, Izumiya Masashi, Imai Toshio, Hippo Yoshitaka
Central Animal Division, National Cancer Center Research Institute, Tokyo, Japan.
Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
Carcinogenesis. 2019 Sep 18;40(9):1142-1152. doi: 10.1093/carcin/bgz024.
Cancers arising from the biliary tract are refractory to conventional therapies, requiring the development of novel therapeutics. However, only a limited number of genetically engineered mouse models have been created, partly because of time-consuming work required. Besides, liver-specific gene manipulation mostly resulted in concurrent development of hepatocellular carcinoma, another type of liver cancer, and gallbladder-restricted gene targeting is still not feasible. Consequently, establishment of cancer type-specific disease modeling remains a technical challenge. To address this issue, we took an alternative cell-based approach to quickly induce tumorigenesis ex vivo. Specifically, murine primary organoids from liver and gallbladder were transduced with lentiviral vectors to reconstitute genetic alterations common in biliary tract cancers, followed by inoculation in immunodeficient mice. Although any single genetic alteration did not induce tumors, mutant Kras and repression of major tumor suppressors cooperated for tumor development within 2 months. Induced lesions varied among normal, dysplastic and papillary lesions to adenocarcinoma, recapitulating multistep tumorigenesis even in a heterotopic situation. We further demonstrated that two putative oncogenes in intrahepatic cholangiocellular carcinoma, mutant Pik3ca and FGFR2-AHCYL1 fusion, were rather modest drivers for liver-derived organoids, probably requiring additional mutations or hepatic niche to robustly induce full-blown tumors. Thus, we showed that cancer cells could be readily generated from primary cells in the biliary tract, at least in cases where genetic factors play dominant roles. Collectively, this study will likely contribute to gaining mechanistic insights into biliary carcinogenesis and providing valuable resources for drug discovery.
胆管癌对传统疗法具有抗性，需要开发新的治疗方法。然而，仅创建了有限数量的基因工程小鼠模型，部分原因是所需的工作耗时。此外，肝脏特异性基因操作大多导致同时发生另一种肝癌——肝细胞癌，而胆囊特异性基因靶向仍然不可行。因此，建立癌症类型特异性疾病模型仍然是一项技术挑战。为了解决这个问题，我们采用了一种基于细胞的替代方法，以在体外快速诱导肿瘤发生。具体而言，用慢病毒载体转导来自肝脏和胆囊的小鼠原代类器官，以重建胆管癌中常见的基因改变，然后接种到免疫缺陷小鼠体内。尽管任何单一的基因改变都不会诱导肿瘤，但突变的Kras和主要肿瘤抑制因子的抑制协同作用，在2个月内促进了肿瘤发展。诱导的病变在正常、发育异常和乳头状病变到腺癌之间各不相同，即使在异位情况下也重现了多步骤肿瘤发生过程。我们进一步证明，肝内胆管细胞癌中的两个假定致癌基因，突变的Pik3ca和FGFR2 - AHCYL1融合体，对肝脏来源的类器官来说是相当温和的驱动因素，可能需要额外的突变或肝脏微环境才能强烈诱导出成熟的肿瘤。因此，我们表明，至少在遗传因素起主导作用的情况下，可以很容易地从胆管中的原代细胞产生癌细胞。总的来说，这项研究可能有助于深入了解胆管癌发生的机制，并为药物发现提供有价值的资源。
