A pancreatic cancer organoid incorporating macrophages reveals the correlation between the diversity of tumor-associated macrophages and cancer cell survival

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is a progressive cancer with a poor prognosis. It contains a complex tumor microenvironment (TME) that includes various stromal cell types. Comprehending cellular communications within the TME is difficult due to a lack of research models that can recapitulate human PDAC-TME. Previously, we recapitulated, in part, the PDAC-TME containing a diversity of cancer-associated fibroblasts (CAFs) in vitro. This was done by establishing a PDAC organoid by co-culturing patient-derived cancer cells with human induced pluripotent stem cell (hiPSC)-derived mesenchymal and endothelial cells, which was designated the fused pancreatic cancer organoid (FPCO). We further incorporated macrophages derived from the THP-1 cell line, which are the source of tumor-associated macrophages (TAMs), a major TME component, into FPCO, which was designated M0-FPCO. Bulk RNA sequencing (RNAseq) analysis revealed that macrophages in M0-FPCO (FPCO-Mac) lost their pro-inflammatory features but acquired pro-angiogenic features. Consistently, the formation of an endothelial cell network was enhanced in M0-FPCO. Single-cell RNA-seq (scRNA-seq) analysis revealed that M0-FPCO contained five TAM subpopulations similar to the corresponding TAM in human PDAC tissue in the integrated analysis, including SPP1⁺-TAM, which has been correlated with tumor angiogenesis and cell proliferation. Focusing on PDAC cells, we found that they could survive longer within the organoid in the presence of TAM. Consistent with the prolonged proliferation and survival of PDAC cells, PDAC subclusters were characterized by proliferative features, such as increased M0-FPCO. Therefore, by establishing a PDAC organoid with macrophages, we recapitulated the diversity of TAMs and identified the role of TAM in endothelial network formation as well as in the modulation of PDAC cell properties. SIGNIFICANCE: PDAC organoids, including macrophages using hiPSC, showed that PDAC-TAM has angiogenic features and contributes to PDAC cell survival.

Keywords: Macrophages; Organoids; PDAC; hiPSC.