Caveolin-1-dependent tenascin C inclusion in extracellular vesicles is required to promote breast cancer cell malignancy.

Caveolin-1 (CAV1) is a protein that in breast cancer increases with disease progression. Extracellular vesicles (EVs) from breast cancer cells with CAV1 also contain Tenascin C (TNC) protein, but the importance of TNC remained to be defined. EVs were identified by size, microscopy and protein analysis. The effects of EVs on breast cancer cells were studied using cells and experiments in animals. CAV1 expression promotes TNC inclusion into EVs, which increased the aggressiveness of recipient breast cancer cells. In animals, only EVs with TNC increased features associated with cancer spread, while EVs lacking TNC reduced tumor growth.