Purpose: Osteosarcoma (OS) mostly affects children and young adults, and has only a 20%-30% 5-year survival rate when metastasized. We aimed to create dual-targeted (extracellular against EphA2 and intracellular against JNK-interacting protein 1 [JIP1]), doxorubicin (DOX)-loaded liposomes to treat OS metastatic disease.
Materials and methods: Cationic liposomes contained N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl-sulfate (DOTAP), cholesterol, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and distearoyl-phosphatidylethanolamine-methyl-poly(ethylene glycol) (DSPE-mPEG) conjugate. EphA2 targeting was accomplished by conjugating YSA peptide to DSPE-mPEG. Vesicles were subsequently loaded with DOX and JIP1 siRNA.
Results: Characteristics assessment showed that 1) size of the bilayered particles was 109 nm; 2) DOX loading efficiency was 87%; 3) siRNA could be successfully loaded at a liposome:siRNA ratio of >24:1; and 4) the zeta potential was 18.47 mV. Tumor-mimicking pH conditions exhibited 80% siRNA and 50.7% DOX sustained release from the particles. Stability studies ensured the protection of siRNA against degradation in serum. OS cell lines showed increased and more pericellular/nuclear localizations when using targeted vesicles. Nontargeted and targeted codelivery caused 70.5% and 78.6% cytotoxicity in OS cells, respectively (free DOX: 50%). Targeted codelivery resulted in 42% reduction in the siRNA target, JIP1 mRNA, and 46% decrease in JIP1 levels.
Conclusion: Our dual-targeted, DOX-loaded liposomes enhance toxicity toward OS cells and may be effective for the treatment of metastatic OS.
Keywords: MAP kinase 8 interacting protein 1; MAPK8IP1; cationic liposome; extracellular targeting; functionalization; intracellular targeting.