PDPN+LTBP1+ cancer-associated fibroblasts induce a liver pre-metastatic niche in gastric cancer via PDPN/YAP/LTBP1 and CCL11/CCR3 axis

As a key component of the tumor microenvironment, cancer-associated fibroblasts (CAFs) exhibit substantial heterogeneity and contribute significantly to tumor growth and progression. However, their involvement in shaping the pre-metastatic niche remains insufficiently characterized. This study demonstrates that extracellular vesicles (EVs) regulated by YAP signaling in podoplanin (PDPN)⁺LTBP1⁺ CAFs activate hepatic stellate cells (HSCs), thereby enhancing gastric Cancer (GC) cell colonization in the liver. Mass spectrometry profiling of EVs from PDPN⁺ and PDPN⁻ CAFs identified latent transforming growth factor beta-binding protein 1 (LTBP1) as a key mediator driving the phenotypic conversion of HSCs into CAF-educated HSCs (CEHs). Exposure to LTBP1-deficient EVs resulted in attenuated CEH-induced malignancy in HGC27 and AGS GC cells. Integrated RNA Sequencing and cytokine array analyses further revealed that LTBP1-containing EVs activated TGF-β signaling in HSCs, leading to CCL11 secretion. This chemokine, in turn, recruited CCR3⁺ metastatic cells to the liver microenvironment. Using a GC liver metastasis model in combination with PET-CT imaging, inhibition of the CCL11/CCR3 axis was shown to suppress CEH-driven tumor growth and metastatic potential. These findings identify LTBP1-enriched EVs from PDPN⁺LTBP1⁺ CAFs as a viable therapeutic target to impede GC liver metastasis.