Integrating multi-modal transcriptomics identifies cellular subtypes with distinct roles in PDAC progression

Area of Science:

• Cancer Biology
• Immunology
• Genomics

Background:

• Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer characterized by an immunosuppressive and fibrotic tumor microenvironment (TME).
• The spatial and functional organization of cellular components within the PDAC TME is not well understood, hindering therapeutic development.

Purpose of the Study:

• To create an integrated transcriptomic atlas of the PDAC TME.
• To spatially map cellular components and identify distinct niches within the PDAC TME.
• To understand the functional roles of specific cell populations in PDAC progression and patient prognosis.

Main Methods:

• Integrated analysis of single-cell RNA sequencing (scRNA-seq), Visium spatial transcriptomics, bulk RNA sequencing, and high-resolution Xenium spatial transcriptomics.
• Validation of key findings using scRNA-seq, bulk datasets, multiplex immunohistochemistry, and spatial imaging.

Main Results:

• Tumor-promoting POSTN⁺ fibroblasts and SPP1⁺ macrophages were spatially correlated and linked to poor prognosis.
• Immune-protective CCL4⁺ CD8⁺ effector T cells and IGHG1⁺ plasma cells were found in distinct niches and associated with improved survival.
• These protective immune cells were detectable despite the immunosuppressive PDAC TME.

Conclusions:

• The PDAC TME exhibits spatially organized, opposing cellular programs: tumor-promoting stromal remodeling and anti-tumor immune activation.
• Targeting pro-tumorigenic fibroblasts and macrophages while enhancing anti-tumor immunity presents a potential therapeutic strategy for PDAC.