Department of Pathology, Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Hepatic Surgery Center, Tongji Medical College, Huazhong University of Science and Technology, Clinical Medicine Research Center for Hepatic Surgery of Hubei Province, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China.
Cancer Res. 2020 Jul 1;80(13):2804-2817. doi: 10.1158/0008-5472.CAN-19-1523. Epub 2020 May 6.
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy characterized by extensive local invasion and systemic spread. In this study, we employed a three-dimensional organoid model of human pancreatic cancer to characterize the molecular alterations critical for invasion. Time-lapse microscopy was used to observe invasion in organoids from 25 surgically resected human PDAC samples in collagen I. Subsequent lentiviral modification and small-molecule inhibitors were used to investigate the molecular programs underlying invasion in PDAC organoids. When cultured in collagen I, PDAC organoids exhibited two distinct, morphologically defined invasive phenotypes, mesenchymal and collective. Each individual PDAC gave rise to organoids with a predominant phenotype, and PDAC that generated organoids with predominantly mesenchymal invasion showed a worse prognosis. Collective invasion predominated in organoids from cancers with somatic mutations in the driver gene (or its signaling partner ). Reexpression of SMAD4 abrogated the collective invasion phenotype in -mutant PDAC organoids, indicating that SMAD4 loss is required for collective invasion in PDAC organoids. Surprisingly, invasion in passaged -mutant PDAC organoids required exogenous TGFβ, suggesting that invasion in -mutant organoids is mediated through noncanonical TGFβ signaling. The Rho-like GTPases RAC1 and CDC42 acted as potential mediators of TGFβ-stimulated invasion in -mutant PDAC organoids, as inhibition of these GTPases suppressed collective invasion in our model. These data suggest that PDAC utilizes different invasion programs depending on status, with collective invasion uniquely present in PDAC with SMAD4 loss. SIGNIFICANCE: Organoid models of PDAC highlight the importance of SMAD4 loss in invasion, demonstrating that invasion programs in -mutant and wild-type tumors are different in both morphology and molecular mechanism.
胰腺导管腺癌 (PDAC) 是一种侵袭性恶性肿瘤，其特征为广泛的局部浸润和全身扩散。在这项研究中，我们使用了人类胰腺癌的三维类器官模型来研究对浸润至关重要的分子改变。通过延时显微镜观察了在胶原 I 中来自 25 个手术切除的人类 PDAC 样本的类器官中的浸润。随后使用慢病毒修饰和小分子抑制剂来研究 PDAC 类器官浸润的分子程序。当在胶原 I 中培养时，PDAC 类器官表现出两种不同的、形态定义明确的浸润表型，即间质型和集体型。每个单独的 PDAC 产生的类器官都具有主要表型，并且主要产生间质型浸润的 PDAC 显示出更差的预后。在具有驱动基因 (或其信号伙伴) 体细胞突变的癌症中，集体浸润在类器官中占主导地位。SMAD4 的重新表达消除了 -突变 PDAC 类器官中的集体浸润表型，表明 SMAD4 缺失是 PDAC 类器官中集体浸润所必需的。令人惊讶的是，在传代的 -突变 PDAC 类器官中，侵袭需要外源性 TGFβ，这表明在 -突变的类器官中，侵袭是通过非经典 TGFβ 信号转导介导的。Rho 样 GTPases RAC1 和 CDC42 作为 TGFβ 刺激的 -突变 PDAC 类器官侵袭的潜在介质，抑制这些 GTPases 可抑制我们模型中的集体侵袭。这些数据表明，PDAC 依赖于 状态使用不同的浸润程序，SMAD4 缺失的集体浸润在 PDAC 中是独特存在的。意义：PDAC 的类器官模型强调了 SMAD4 缺失在浸润中的重要性，表明在 -突变和 野生型肿瘤中，侵袭程序在形态和分子机制上都不同。
