Characterization of cellular and extracellular plasma membrane vesicles from a non-metastasizing XXXX (Eb) and its metastasizing variant (ESb).

@entity19 @entity1718 @entity5 @entity706
Plasma membrane fragments from two variants of a @entity19 @entity706 , Eb and ESb, with different metastatic capacity were investigated. Plasma membranes were isolated from @entity5 cells recovered from the peritoneal cavity. They differed in their lipid composition, indicating a more fluid state of the plasma membranes derived from the highly metastatic @entity5 line ESb. Extracellular membrane vesicles could be isolated from the ascites of the @entity5 -bearing @entity19 . The shedding capacity of ESb cells was much higher than that of Eb cells. The extracellular membranes by chemical analysis and the measurement of marker enzymes proved to be derived from the plasma membranes. However, they differed from the plasma membranes from which they were derived in several aspects: the lipid to protein ratio was diminished; the activities of some plasma membrane-associated enzymes were lower while others were identical in plasma membranes and extracellular membranes; the content of @entity1718 in phospholipids was enhanced in extracellular membranes. These effects were more pronounced in the highly metastasizing @entity5 line ESb. It is thus concluded that shedding of extracellular membranes is not a random process. The biochemical differences found in the plasma membranes and the extracellular membranes of the two @entity5 lines are discussed with respect to the different metastatic capacity of the @entity5 .
