Exosomes are produced from mammalian cells when multivesicular endosomes fuse 
with the plasma membrane, releasing their intralumenal vesicles. In this study 
we assessed the effects of MOPIPP, a novel indole-based chalcone, and 
vacuolin-1, a distinct triazine-based compound, on exosome production in 
cultured glioblastoma and 293T cells. Both compounds promote vacuolization of 
late endosome compartments and interfere with trafficking of late endosomes to 
lysosomes, without significant cytotoxicity. The results show that vacuolated 
cells treated with these compounds release exosomes with morphologies similar to 
untreated controls. However, both compounds trigger multi-fold increases in 
release of exosome marker proteins (e.g., CD63, Alix) in exosome fractions 
collected from equivalent numbers of cells. Despite the marked increase in 
exosome production, the profiles of selected miRNA cargoes carried by the 
exosomes were generally similar in cells treated with the compounds. Insofar as 
MOPIPP and vacuolin-1 seem able to increase the overall yield of exosomes from 
cultured cells, they might be useful for efforts to develop exosome-based 
therapeutics.