The lethality, chemoresistance and metastatic characteristics of cancers are associated with phenotypically plastic cancer stem cells (CSCs). How the non-cell autonomous signalling pathways and cell-autonomous transcriptional machinery orchestrate the stem cell-like characteristics of CSCs is still poorly understood. Here we use a quantitative proteomic approach for identifying secreted proteins of CSCs in pancreatic cancer. We uncover that the cell-autonomous E2F1/4-pRb/RBL2 axis balances non-cell-autonomous signalling in healthy ductal cells but becomes deregulated upon KRAS mutation. E2F1 and E2F4 induce whereas pRb/RBL2 reduce WNT ligand expression (e.g. WNT7A, WNT7B, WNT10A, WNT4) thereby regulating self-renewal, chemoresistance and invasiveness of CSCs in both PDAC and breast cancer, and fibroblast proliferation. Screening for epigenetic enzymes identifies GCN5 as a regulator of CSCs that deposits H3K9ac onto WNT promoters and enhancers. Collectively, paracrine signalling pathways are controlled by the E2F-GCN5-RB axis in diverse cancers and this could be a therapeutic target for eliminating CSCs.

癌症的致死性、化疗耐药性和转移特征与表型可塑性癌症干细胞（CSC）相关。非细胞自主信号通路和细胞自主转录机制如何协调 CSC 的干细胞样特征仍知之甚少。在这里，我们使用定量蛋白质组学方法来鉴定胰腺癌中 CSC 的分泌蛋白。我们发现细胞自主 E2F1/4-pRb/RBL2 轴平衡健康导管细胞中的非细胞自主信号传导，但在 KRAS 突变时变得失调。 E2F1和E2F4诱导而pRb/RBL2降低WNT配体表达（例如WNT7A、WNT7B、WNT10A、WNT4），从而调节PDAC和乳腺癌中CSC的自我更新、化学抗性和侵袭性以及成纤维细胞增殖。表观遗传酶筛选发现 GCN5 是 CSC 的调节因子，可将 H3K9ac 沉积到 WNT 启动子和增强子上。总的来说，在多种癌症中，旁分泌信号通路由 E2F-GCN5-RB 轴控制，这可能是消除 CSC 的治疗靶点。