Cancer-associated fibroblasts drive lung adenocarcinoma progression via THBS2-mediated epithelial-mesenchymal transition.

The role of cancer-associated fibroblasts (CAFs) in the initiation and invasion phases of human lung adenocarcinoma (LUAD) development is not fully understood. In this study, we utilized single-cell RNA sequencing, spatial transcriptomics, and a combination of in vivo and in vitro models to decode the dynamics of tumor-stroma interactions during human LUAD progression, focusing primarily on adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IAC). We identified a matrix CAF (mCAF) subtype characterized by high THBS2 expression, which was closely associated with poor clinical outcomes, tumor recurrence, and the invasive dynamics of LUAD. Spatial transcriptomics and multiplex immunohistochemistry analysis revealed that this CAF subpopulation was closely associated with tumor cells, with clear spatial colocalization. In vivo and in vitro experiments demonstrated that THBS2 secreted by these mCAFs directly binds to SDC4 on tumor cells, enhancing tumor epithelial-mesenchymal transition (EMT) programs. This study highlights THBS2+ mCAFs as key regulators of tumor-stroma interactions and identifies the THBS2-SDC4-EMT axis as a potential therapeutic target in LUAD.