ECM deposition is driven by caveolin1-dependent regulation of exosomal biogenesis and cargo sorting

The composition and physical properties of the extracellular matrix (ECM) critically influence tumor progression, but the molecular mechanisms underlying ECM layering are poorly understood. Tumor-stroma interaction is critically dependent on cell-cell communication mediated by exosomes, small vesicles generated within multivesicular bodies (MVBs). Here, we show that caveolin-1 (Cav1) is a central modulator of both exosome biogenesis and exosomal protein cargo sorting through the regulation of cholesterol content at the endosomal compartment/MVBs. Quantitative proteomics profiling revealed that Cav1 is required for exosomal sorting of ECM protein cargo subsets including tenascin-C (TnC), and for fibroblast-derived exosomes to efficiently depose ECM and promote tumor cell invasiveness. Cav1-driven exosomal ECM deposition not only promotes local stromal remodeling, but also the generation of distant ECM-enriched stromal niches. These results support a model by which Cav1 is a central regulatory hub for tumor-stroma interactions through a novel exosome-dependent ECM deposition mechanism.

Linked studies: MTBLS1977