Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan.
Cancer Res. 2011 Dec 1;71(23):7250-8. doi: 10.1158/0008-5472.CAN-11-0903. Epub 2011 Nov 16.
We established an inducible Kras(G12D)-driven lung adenocarcinoma in CCSP-rtTA/TetO-Cre/LSL-Kras(G12D) mice that enable pursuits of the cellular and molecular processes involved in Kras-induced tumorigenesis. To investigate the cellular origin of this cancer, we first report a strategy using fluorescence-activated cell sorting fractionation that could highly enrich bronchiolar Clara and alveolar type II cells, respectively. The EpCAM(+)MHCII(-) cells (bronchiolar origin) were more enriched with tumorigenic cells in generating secondary tumors than EpCAM(+)MHCII(+) cells (alveolar origin) in primary tumors that had been already initiated with oncogenic Kras activation. In addition, secondary tumors derived from EpCAM(+)MHCII(-) cells showed diversity of tumor locations compared with those derived from EpCAM(+)MHCII(+) cells. In the alveolar region, secondary tumors from EpCAM(+)MHCII(-) cells expressed not only bronchiolar epithelial marker, panCK, but also differentiation marker, proSPC, consistent with the notion that cancer-initiating cells display not only the abilities for self-renewal but also the features of differentiation to generate heterogeneous tumors with phenotypic diversity. Furthermore, high level of ERK1/2 activation and colony-forming ability as well as lack of Sprouty-2 expression were also observed in EpCAM(+)MHCII(-) cells. Therefore, these results suggest that bronchiolar Clara cells are the origin of cells and tumorigenesis for Kras(G12D)-induced neoplasia in the lungs.
我们在 CCSP-rtTA/TetO-Cre/LSL-Kras(G12D) 小鼠中建立了一种可诱导的 Kras(G12D)驱动的肺腺癌，使我们能够研究参与 Kras 诱导肿瘤发生的细胞和分子过程。为了研究这种癌症的细胞起源，我们首先报告了一种使用荧光激活细胞分选（FACS）分离的策略，该策略可以分别高度富集小支气管 Clara 细胞和肺泡 II 型细胞。在已经启动致癌性 Kras 激活的原发性肿瘤中，EpCAM(+)MHCII(-) 细胞（支气管起源）比 EpCAM(+)MHCII(+) 细胞（肺泡起源）更能富集致瘤细胞来生成次级肿瘤。此外，源自 EpCAM(+)MHCII(-) 细胞的次级肿瘤与源自 EpCAM(+)MHCII(+) 细胞的次级肿瘤相比，其肿瘤位置具有多样性。在肺泡区域，源自 EpCAM(+)MHCII(-) 细胞的次级肿瘤不仅表达支气管上皮标志物 panCK，还表达分化标志物 proSPC，这与癌症起始细胞不仅具有自我更新能力，还具有分化特征以产生具有表型多样性的异质性肿瘤的观点一致。此外，在 EpCAM(+)MHCII(-) 细胞中还观察到 ERK1/2 激活水平高、集落形成能力以及 Sprouty-2 表达缺失。因此，这些结果表明，小支气管 Clara 细胞是 Kras(G12D)诱导肺肿瘤发生的细胞和肿瘤发生的起源。
