Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, United States
Nina Steele
Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States; Department of Surgery, University of Michigan, Ann Arbor, United States
Li Zhang
Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, United States
Peter Sajjakulnukit
Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, United States
Anthony Andren
Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, United States
Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, United States
Venkatesha Basrur
Department of Pathology, University of Michigan, Ann Arbor, United States
Yaqing Zhang
Department of Surgery, University of Michigan, Ann Arbor, United States
Alexey I Nesvizhskii
Department of Pathology, University of Michigan, Ann Arbor, United States; Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, United States
Marina Pasca di Magliano
Department of Surgery, University of Michigan, Ann Arbor, United States; Rogel Cancer Center, University of Michigan, Ann Arbor, United States
Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, United States; Rogel Cancer Center, University of Michigan, Ann Arbor, United States; Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of Michigan, Ann Arbor, United States
The pancreatic ductal adenocarcinoma microenvironment is composed of a variety of cell types and marked by extensive fibrosis and inflammation. Tumor-associated macrophages (TAMs) are abundant, and they are important mediators of disease progression and invasion. TAMs are polarized in situ to a tumor promoting and immunosuppressive phenotype via cytokine signaling and metabolic crosstalk from malignant epithelial cells and other components of the tumor microenvironment. However, the specific distinguishing features and functions of TAMs remain poorly defined. Here, we generated tumor-educated macrophages (TEMs) in vitro and performed detailed, multiomic characterization (i.e., transcriptomics, proteomics, metabolomics). Our results reveal unique genetic and metabolic signatures of TEMs, the veracity of which were queried against our in-house single-cell RNA sequencing dataset of human pancreatic tumors. This analysis identified expression of novel, metabolic TEM markers in human pancreatic TAMs, including ARG1, ACLY, and TXNIP. We then utilized our TEM model system to study the role of mutant Kras signaling in cancer cells on TEM polarization. This revealed an important role for granulocyte–macrophage colony-stimulating factor (GM-CSF) and lactate on TEM polarization, molecules released from cancer cells in a mutant Kras-dependent manner. Lastly, we demonstrate that GM-CSF dysregulates TEM gene expression and metabolism through PI3K–AKT pathway signaling. Collectively, our results define new markers and programs to classify pancreatic TAMs, how these are engaged by cancer cells, and the precise signaling pathways mediating polarization.
