Figure 7.

Brain tumor cell lines release exosomes into the media. Exosomes were isolated from the spent media from cell lines D54MG and SMA560 by differential centrifugation. A, Exosomes recovered in the final pellets were observed by electron microscopy after uranyl acetate negative staining (arrows). B, Western blots of exosome material show that HSPs 90, 70, 60, and 27 are present. For the SMA560 line, the asterisk indicates a rodent mitochondrial small HSP of ∼37 kDa rather than the expected 20–30 kDa.