Wnt Signaling Shapes the Histologic Variation in Diffuse Gastric Cancer
Wnt Signaling Shapes the Histologic Variation in Diffuse Gastric Cancer
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DOI：
10.1053/j.gastro.2020.10.047
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发表时间：
2021-02-06
期刊：
影响因子：
29.4
通讯作者：
Sato, Toshiro
中科院分区：
文献类型：
--
作者：
Togasaki, Kazuhiro;Sugimoto, Shinya;Sato, Toshiro
背景和目标：弥漫型胃癌（GC）目前分为印戒细胞癌（SRCC）和非SRCC，称为粘附性差的癌，未另作说明（PCC-NOS）。虽然这些亚型被认为是独立的，但它们经常在同一肿瘤中共存，这就提出了它们是否存在克隆差异的问题。为了解决这个问题，我们建立了一个人类弥漫性GC的实验平台，可以精确建模组织学亚型。方法：建立了7个患者来源的弥漫性GC类器官系，其特征在于组织病理学分析，原位杂交和基因表达分析。对于弥漫性GC的遗传建模，我们敲除了人正常胃类器官中的CDH 1和/或TP 53。将绿色荧光蛋白标记的GC类器官异种移植到免疫缺陷小鼠中用于体内评估。结果：去除Wnt和R-spondin后，PCC-NOS类器官转化为SRCC样结构。这种形态学变化导致Wnt靶基因和胃干细胞基因（包括LGR 5）下调，分化标志物（如KRT 20和MUCs）升高。在3例患者来源的胃癌组织中证实了Wnt靶基因表达与组织学亚型之间的相关性。在体内，单克隆衍生的类器官形成了包含2个不同组织学区室的肿瘤，每个区室对应于SRCC和PCC-NOS。从PCC-NOS到SRCC组织学的转变反映了周围表达R-spondin的成纤维细胞的丰度。结论：SRCC和PCC-NOS在克隆上完全相同，其形态受细胞外Wnt和R-spondin表达的调控。我们的研究结果解码了基因突变和肿瘤环境如何塑造人类弥漫性GC的病理组织学和生物学表型。
BACKGROUND AND AIMS: Diffuse-type gastric cancer (GC) is currently subdivided into signet-ring cell carcinoma (SRCC) and non-SRCC, referred to as poorly cohesive carcinoma not otherwise specified (PCC-NOS). Although these subtypes are considered to be independent, they often coexist in the same tumors, raising a question of whether they clonally differ or not. To tackle this question, we established an experimental platform for human diffuse GC that enables accurate modeling of histologic subtypes. METHODS: Seven patient-derived diffuse GC organoid lines were established, characterized by histopathologic analysis, in situ hybridization, and gene expression analysis. For genetic modeling of diffuse GC, we knocked out CDH1 and/or TP53 in human normal gastric organoids. Green fluorescent protein-labeled GC organoids were xenotransplanted into immune-deficient mice for in vivo assessment. RESULTS: PCC-NOS organoids transformed into SRCC-like structures on removal of Wnt and R-spondin from the culture medium. This morphologic change paralleled downregulation of Wnt-target and gastric stem cell genes, including LGR5, and elevation of differentiation markers, such as KRT20 and MUCs. The association between Wnt target gene expression and histologic subtypes was confirmed in 3 patient-derived GC tissues. In vivo, single clone-derived organoids formed tumors that comprised 2 distinct histologic compartments, each corresponding to SRCC and PCC-NOS. The transition from PCC-NOS to SRCC histology reflected the abundance of surrounding R-spondin-expressing fibroblasts. CONCLUSIONS: SRCC and PCC-NOS were clonally identical, and their morphology was regulated by extracellular Wnt and R-spondin expression. Our results decoded how genetic mutations and the tumor environment shape pathohistologic and biologic phenotypes in human diffuse GCs.