A novel pancreatic ductal adenocarcinoma organoid recapitulating tumor microenvironment reveals macrophage-driven enhanced cancer cell survival [RNA-Seq]

Pancreatic ductal adenocarcinoma (PDAC) is a progressive cancer with only about 12 % of a 5-year survival rate. PDAC generally shows strong chemoresistance, which has been correlated with the tumor microenvironment (TME) of PDAC consisting of various types of stromal cells. Recent single-cell RNA sequence (scRNAseq) analyses demonstrate that a high percentage of myeloid cells in TME stroma cells is related to poor prognosis, and, among myeloid cells, tumor associated macrophages (TAM) are the most abundant population. However, their functions in PDAC malignancy remain largely unknown. Previously, we established a PDAC-organoid associated with an artificial TME by co-culturing patient-derived cancer cells, human induced pluripotent stem cell (hiPSC) derived mesenchymal and endothelial cells, which is called fused pancreatic cancer organoid (FPCO). Here, we further incorporated macrophages into FPCO and named it M0-FPCO. After 1 week of organoid culture, the macrophages in M0-FPCO expressed the conventional markers of M2-macrophages, such as CD163 and CD206. However, bulk RNAseq analysis showed that macrophages in M0-FPCO (FPCO-Mac) have distinct characteristics as compared with M2-macrophages induced with IL4 and 13. scRNAseq of M0-FPCO further demonstrated that FPCO-Mac was divided into 6 populations including Granulin+-TAM and SPP1+-TAM, which had been identified in human PDAC tissue. Furthermore, the number of PDAC cells was reduced in FPCO but not in M0-FPCO between 1 and 2 weeks of organoid culture, suggesting that cancer cells could survive longer or are protected from cell death in the presence of TAM. Moreover, the bulk-RNAseq analysis of the surviving M0-FPCO unveiled a GALE potentially associated with a worse prognosis in PDAC patients. Our novel PADC organoid including macrophage (M0-FPCO) replicated the PDAC-TAM features and elucidated their protumorigenic function.