Epithelial and Mesenchymal Pancreatic Cancer Cells Exhibit Different Stem Cell Phenotypes Being Associated with Different Metastatic Propensity

Pancreatic ductal adenocarcinoma (PDAC) is mostly diagnosed at advanced or even metastasized stages limiting patient´s prognosis. Metastasis requires high tumor cell plasticity implying phenotypic switching in response to changing environments. Here, Epithelial-Mesenchymal-Transition (EMT), being associated with the gain of cancer stem cell (CSC) properties, and its reversion are important. Since it is poorly understood whether different CSC-phenotypes exist along the EMT-axis and how these impact malignancy-associated properties, we aimed to characterize CSC-populations of epithelial and mesenchymal PDAC cells. Single-cell cloning revealed CSC (Holoclone) and non-CSC (Paraclone) clones from the PDAC cell lines Panc1 and Panc89. Panc1 Holoclone cells showed a mesenchymal phenotype dominated by high expression of the stemness marker Nestin, while Panc89 Holoclone cells exhibited a SOX2-dominated epithelial phenotype. Panc89 Holoclone cells showed enhanced cell growth and self-renewal capacity but slow cluster-like invasion. Contrarily, Panc1 Holoclone cells showed slower cell growth and self-renewal ability but were highly invasive. Moreover, cell variants differentially responded to chemotherapy. In vivo, Panc1 and Panc89 cell variants significantly differed regarding number and size of metastases as well as organ manifestation leading to different survival outcomes. Overall, these data support the existence of different CSC-phenotypes along the EMT-axis in PDAC manifesting in different metastatic propensities.