Lipid-based delivery vehicles are provided. Nanoparticulate compositions typically including a p21 activated kinase (PAK) inhibitor and a lipid-based delivery vehicle are also provided. In preferred embodiments, the lipid-based delivery vehicle is a liposome, most preferably a sterically-stabilized liposome. Typically the lipid-based delivery vehicle includes one or more phospholipids, and optionally a sterol. In some embodiments, at least one of the phospholipids is PEGylated. In particular embodiments, the lipid-based delivery vehicle includes DSPC, DSPE-PEG2000, and cholesterol. In specific embodiments, the ratio of DSPC, DSPE-PEG, and cholesterol is 9:1:5. The nanoparticulate composition typically includes a PAK inhibitor, preferably a PAK-1 inhibitor such as IPA-3 or a derivative, prodrug, or pharmaceutically acceptable salt thereof. Methods of use, for example methods of treating cancer, particularly prostate and breast cancer by administering the composition to subjects in need thereof, are also provided.
