Single-cell profiling of microenvironment components by spatial localization in pancreatic ductal adenocarcinoma

Rationale: The biology of the pancreatic ductal adenocarcinoma (PDAC) is heterogenous, but how heterogenity of the tumor microenvironment contributes to disparate patient outcomes remains essentially unstudied. Methods: A strategy employing multiplex digital spatial profiling (mplxDSP) technology was employed to evaluate the nature and dynamics of microenvironment components including cancer associated fibroblasts (CAFs) and infiltrating immune cells at the single-cell level based upon their spatial relationship within the tumor. Results: We report that myofibroblasts directly adjacent to PDAC tumors comparatively overexpress genes (BATF3, IL12B, ITGB8, CD4 and IFNAR1), constructing pathways prone to stimulating an adaptive immune response. Markers of innate immune cells (Natural Killer cells, Dendritic Cells and macrophages) are predominant in CD45+ cells immediately adjacent to PDAC tumor, however, the checkpoint protein CTLA4 is also overwhelmingly expressed, fostering tolerance. Finaly, mRNA profiling of adjacent CAFs identified clusters of genes that correlate with survival. Conclusion: CAFs and leukocytes in close proximity to PDAC significantly differ from those remote from the tumor, providing insight into microenvironment influence on immune tolerance mediated through relative populations of leukocytes and subsets of CAFs and monocytes. mRNA expression profiling of CAFs adjacent to PDAC cells may hold promise for prognostication.

Automated summary

This study explores the impact of tumor microenvironment heterogeneity on patient outcomes in pancreatic ductal adenocarcinoma (PDAC) at the single-cell level using mplxDSP technology. The results suggest that myofibroblasts adjacent to PDAC tumors overexpress certain genes, promoting adaptive immune response. The proximity of cancer-associated fibroblasts and leukocytes to the tumor significantly differs from those farther away, shedding light on the influence of microenvironment on immune tolerance.