Metastasis development is the leading cause of cancer-related mortality in pancreatic ductal adenocarcinoma (PDAC) and yet, few preclinical systems to recapitulate its full spreading process are available. Thus, modeling of tumor progression to metastasis is urgently needed. In this work, we describe the generation of highly metastatic PDAC patient-derived xenograft (PDX) mouse models and subsequent single-cell RNA-sequencing (RNA-seq) of circulating tumor cells (CTC), isolated by human HLA sorting, to identify altered signaling and metabolic pathways, as well as potential therapeutic targets. The mouse models developed liver and lung metastasis with a high reproducibility rate. Isolated CTCs were highly tumorigenic, had metastatic potential, and single-cell RNA-seq showed that their expression profiles clustered separately from those of their matched primary and metastatic tumors and were characterized by low expression of cell-cycle and extracellular matrix–associated genes. CTC transcriptomics identified survivin (BIRC5), a key regulator of mitosis and apoptosis, as one of the highest upregulated genes during metastatic spread. Pharmacologic inhibition of survivin with YM155 or survivin knockdown promoted cell death in organoid models as well as anoikis, suggesting that survivin facilitates cancer cell survival in circulation. Treatment of metastatic PDX models with YM155 alone and in combination with chemotherapy hindered the metastatic development resulting in improved survival. Metastatic PDX mouse model development allowed the identification of survivin as a promising therapeutic target to prevent the metastatic dissemination in PDAC.

中文翻译：

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通过循环肿瘤细胞的单细胞转录组学分析发现控制胰腺癌转移的新靶点

转移的发展是胰腺导管腺癌 (PDAC) 中癌症相关死亡率的主要原因，然而，很少有临床前系统可以概括其完整的扩散过程。因此，迫切需要对肿瘤进展到转移的建模。在这项工作中，我们描述了高转移性 PDAC 患者来源的异种移植 (PDX) 小鼠模型的生成和随后的循环肿瘤细胞 (CTC) 的单细胞 RNA 测序 (RNA-seq)，通过人类 HLA 分选分离，以识别改变信号和代谢途径，以及潜在的治疗目标。小鼠模型以高再现率发展了肝和肺转移。分离的 CTC 具有高度致瘤性，具有转移潜力，和单细胞 RNA-seq 显示它们的表达谱与匹配的原发性和转移性肿瘤的表达谱分开聚集，其特征是细胞周期和细胞外基质相关基因的低表达。CTC 转录组学鉴定了有丝分裂和细胞凋亡的关键调节因子 survivin (BIRC5) 是转移扩散过程中上调最高的基因之一。用 YM155 或 survivin 敲低对 survivin 的药理学抑制促进类器官模型和失巢凋亡中的细胞死亡，表明 survivin 促进癌细胞在循环中的存活。单独使用 YM155 和联合化疗治疗转移性 PDX 模型会阻碍转移的发展，从而提高生存率。