Cytotoxicity of nanoparticles examined in prostate cancer cells using the Cell Counting Kit-8 assay. Cell viability in (A) DU145 CD44+ cells, (B) DU145 CD44− cells, (C) 22RV1 CD44+ cells and (D) 22RV1 CD44− cells. Data are presented as the mean ± standard deviation (n=3). SM-LPN-CD44, salinomycin-encapsulated lipid-poly(lactide-co-glycolide acid) nanoparticles linked with CD44 antibodies; SM-LPN, salinomycin-encapsulated lipid-poly(lactide-co-glycolide acid) nanoparticles; LPN-CD44, blank lipid-poly(lactide-co-glycolide acid) nanoparticles linked with CD44 antibodies; CD, cluster of differentiation.