Department of Biomedical Sciences and.
Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
JCI Insight. 2017 Oct 5;2(19):92232. doi: 10.1172/jci.insight.92232.
Pancreatic ductal adenocarcinomas (PDAs) are desmoplastic and can undergo epithelial-to-mesenchymal transition to confer metastasis and chemoresistance. Studies have demonstrated that phenotypically and functionally distinct stromal cell populations exist in PDAs. Fibroblast activation protein-expressing (FAP-expressing) cells act to enhance PDA progression, while α-smooth muscle actin myofibroblasts can restrain PDA. Thus, identification of precise molecular targets that mediate the protumorigenic activity of FAP+ cells will guide development of therapy for PDA. Herein, we demonstrate that FAP overexpression in the tumor microenvironment correlates with poor overall and disease-free survival of PDA patients. Genetic deletion of FAP delayed onset of primary tumor and prolonged survival of mice in the KPC mouse model of PDA. While genetic deletion of FAP did not affect primary tumor weight in advanced disease, FAP deficiency increased tumor necrosis and impeded metastasis to multiple organs. Lineage-tracing studies unexpectedly showed that FAP is not only expressed by stromal cells, but can also be detected in a subset of CD90+ mesenchymal PDA cells, representing up to 20% of total intratumoral FAP+ cells. These data suggest that FAP may regulate PDA progression and metastasis in cell-autonomous and/or non-cell-autonomous fashions. Together, these data support pursuing FAP as a therapeutic target in PDA.
胰腺导管腺癌(PDAs)是一种富于细胞外基质的肿瘤,可以发生上皮间质转化,从而导致转移和化疗耐药。研究表明,PDAs 中存在表型和功能不同的间质细胞群体。成纤维细胞激活蛋白表达(FAP 表达)细胞可促进 PDA 的进展,而α-平滑肌肌动蛋白肌成纤维细胞则可抑制 PDA。因此,鉴定介导 FAP+细胞促肿瘤活性的确切分子靶点将指导 PDA 治疗的发展。在此,我们证明肿瘤微环境中 FAP 的过表达与 PDA 患者总体和无病生存率降低相关。在 KPC 小鼠 PDA 模型中,FAP 的基因缺失延迟了原发肿瘤的发生,并延长了小鼠的存活时间。虽然 FAP 的基因缺失对晚期疾病中的原发肿瘤重量没有影响,但 FAP 缺失增加了肿瘤坏死并阻碍了向多个器官的转移。谱系追踪研究出人意料地表明,FAP 不仅表达于间质细胞,而且还可在一部分 CD90+间充质 PDA 细胞中检测到,占总肿瘤内 FAP+细胞的 20%左右。这些数据表明,FAP 可能以细胞自主和/或非细胞自主的方式调节 PDA 的进展和转移。综上所述,这些数据支持将 FAP 作为 PDA 的治疗靶点进行研究。