Cationic liposome-mediated incorporation of prostatic acid phosphatase protein into human prostate carcinoma cells.

Lipofectin, the commercially available cationic liposome, was used to introduce the purified prostatic acid phosphatase protein into the established human prostate carcinoma cells. The incorporated phosphatase protein which retained its enzymatic activity as demonstrated by the tartrate-sensitive acid phosphatase assay was localized in the cytoplasm by immunofluorescence staining. Further, cells that were treated with phosphatase/Lipofectin complexes expressed a decreased phosphotyrosine level, presumably due to the endogenous protein tyrosine phosphatase activity of the acid phosphatase protein. A cationic liposome such as lipofectin may thus be employed to mediate transport of other acidic proteins into cells, providing a way to examine their biological functions in vivo.