Single-nucleus RNA sequencing reveals the effects of key regulators on human pancreatic adenocarcinoma and its tumor microenvironment.

BACKGROUNDThe aggressive nature and poor prognosis of pancreatic ductal adenocarcinoma (PDAC) are closely linked to its complex tumor microenvironment (TME). However, a detailed mapping of the TME's cellular landscape and its interactions with cancer cells at single-cell resolution is still lacking, limiting our understanding of the disease. This study aims to utilize single-nucleus RNA sequencing technology to construct a panoramic single-cell transcriptomic map of the PDAC TME. Furthermore, the expression characteristics of the key differential genes REG1A and REG1B in the early progression of PDAC and the regulation of the tumor microenvironment are validated through clinical samples.

METHODSTo dissect the complex TME of PDAC, we employed single-nucleus RNA sequencing. By performing an integrated analysis of freshly collected and publicly available human PDAC samples, we identified a critical regulatory network involving REG1 and other key factors that modulate tumor progression and metastasis. Our data further delineated the interplay among heterogeneous cancer cell states and distinct populations of cancer-associated fibroblasts and macrophages.

RESULTSTumor regions showed enrichment of acinar cells and depletion of fibroblasts and endothelial cells, reflecting epithelial and stromal remodeling. Ductal and acinar cells exhibited strong transcriptional reprogramming, with upregulation of REG1A, REG1B and SEMA3C. The expression levels of REG1A and REG1B were quantified by real time quantitative polymerase chain reaction (RT-qPCR) in 48 paired PDAC tissue samples. The results indicated significant overexpression of both genes in tumor tissues. Compared with peritumoral tissues, REG1A and REG1B showed significant upregulation in early-stage (stage I) tumors, but not in advanced stages (stage III/IV), suggesting their potential role in promoting early PDAC tumorigenesis. Furthermore, elevated expression of these genes was confirmed to be significantly associated with unfavorable prognosis in patients.

CONCLUSIONSOur work constructs a detailed single-cell transcriptomic atlas of the PDAC microenvironment. It implicates REG1A and REG1B as promising candidates for both early diagnostic biomarkers and novel therapeutic intervention points.