Human colon organoids reveal distinct physiologic and oncogenic Wnt responses

Constitutive Wnt activation upon loss of Adenoma polyposis coli (APC) acts as main driver of colorectal cancers (CRC). Targeting Wnt signaling has proven difficult because the pathway is crucial for homeostasis and stem cell renewal. To distinguish oncogenic from physiologic Wnt activity, we have performed comprehensive transcriptome and proteome profiling in human colon organoids. Culture in the presence or absence of exogenous ligand allowed us to discriminate receptor-mediated signaling from the effects of CRISPR/Cas9 induced APC loss. We could catalogue two non-overlapping molecular signatures that were stable at distinct levels of stimulation. Newly identified markers for normal colon stem/progenitor cells and adenomas were validated by immunohistochemistry and flow cytometry. We found that oncogenic Wnt signals are associated with good prognosis in tumors of the consensus molecular subtype 2 (CMS2). In contrast, receptor-mediated signaling was linked to CMS4 tumors and poor prognosis. Together, our data represent a valuable resource for biomarkers that allow more precise stratification of Wnt responses in CRC.

腺瘤性息肉病蛋白（Adenoma polyposis coli, APC）缺失导致的组成型Wnt激活是结直肠癌（colorectal cancers, CRC）的主要驱动因素。由于Wnt信号通路在机体稳态维持与干细胞更新中发挥关键作用，靶向该通路的干预策略始终面临挑战。为区分致癌性与生理性Wnt活性，我们对人类结肠类器官开展了全面的转录组与蛋白质组谱学分析。通过在培养体系中添加或移除外源性配体，我们能够有效区分受体介导的信号通路活性与CRISPR/Cas9诱导的APC缺失所产生的生物学效应。本研究鉴定出两种互不重叠的分子特征谱，其在不同刺激强度下均保持稳定。我们通过免疫组织化学与流式细胞术，对新鉴定出的正常结肠干细胞/祖细胞及腺瘤标记物进行了验证。研究发现，在共识分子亚型2（consensus molecular subtype 2, CMS2）的结直肠肿瘤中，致癌性Wnt信号与良好预后显著相关；与之相反，受体介导的Wnt信号则与CMS4型肿瘤及不良预后密切关联。综上，本研究数据可为结直肠癌中Wnt应答的精准分层提供极具价值的生物标记物资源。