LARGE ACIDIC VESICLES ARE CORRELATED WITH INVITRO INVASIVE POTENTIAL OF BREAST-CANCER CELLS

Human breast cancer cells include large acidic vesicles (LAVs) contain ing endocytosed extracellular matrix (P. Montcourrier et al., Cancer R es., 50, 1990, p. 6045-6054) and mature cathepsin D, a lysosomal prote ase associated with metastasic risk. We show that metastatic breast ca ncer MDA-MB231 cells migrating in vitro through a Matrigel gel in a mo dified Boyden chamber were enriched in LAVs (28 % compared to 6 % befo re plating) as visualized by acridine orange fluorescence. This is the first evidence that LAVs are associated with invasiveness of cancer r ather than with an apoptotic process.