ATP6V1C1 in cancer-associated fibroblast-derived extracellular vesicles affects the metastasis and therapeutic sensitivity of lung adenocarcinoma

Cancer-associated fibroblast (CAF)-derived extracellular vesicles (EVs) are known to promote lung adenocarcinoma (LUAD) progression, yet the specific protein cargos responsible for this effect remain poorly defined. In this study, we generated a library of patient-derived fibroblasts (PDFs) from paired LUAD tumor and adjacent noncancerous tissues. Through integrated transcriptomic analysis and surface marker identification, we characterized CAFs and normal fibroblasts (NFs), subsequently isolating a distinct CAF subset with high pro-migratory activity using transwell assays. Quantitative proteomic profiling of EVs from 30 matched CAF-NF pairs revealed a high-quality dataset of 2,492 proteins and identified ATP6V1C1, a subunit of the V-ATPase complex, as a highly enriched protein in pro-migratory CAF-EVs. We further demonstrated that CAF-EV-mediated transfer of ATP6V1C1 drove LUAD cell migration and metastasis, a finding robustly validated in cell lines, patient-derived cells (PDCs), and an orthotopic patient-derived xenograft (PDX) model. At the molecular level, EV-delivered ATP6V1C1 suppressed insulin-like growth factor binding protein 3 (IGFBP3) by downregulating the transcription factor ID1. This suppression of IGFBP3 not only triggered epithelial-mesenchymal transition (EMT) but also amplified the IGF1/IGF1R/Akt/ERK oncogenic pathway driven by CAF-secreted IGF1. This dual action creates a self-reinforcing feed-forward loop that exacerbates metastasis. A high-throughput screen using PDCs and patient-derived organoids (PDOs) identified dronedarone as a promising drug repurposing candidate; its therapeutic efficacy was inversely correlated with ATP6V1C1 expression. Targeting ATP6V1C1 disrupted cholesterol homeostasis and synergized with dronedarone to overcome resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in preclinical models. In conclusion, our findings unveil ATP6V1C1 as a dual regulator of LUAD metastasis and propose a novel stroma-targeted combination therapy to suppress tumor progression and combat drug resistance.