Peptide T7-modified polypeptide with disulfide bonds for targeted delivery of plasmid DNA for gene therapy of prostate cancer

BACKGROUND: Vectors are essential for successful gene delivery. In the present study, a tumor-targeting cationic gene vector, known as the disulfide cross-linked arginine-aspartic acid peptide modified by HAIYPRH (T7) peptide (CRD-PEG-T7), was designed for targeted delivery of plasmid DNA (pDNA) for gene therapy of prostate cancer (PCa). METHODS: The structure of CRD-PEG-T7 was determined and the cellular uptake efficacy, gene transfection efficacy, cytotoxicity, and the targeting effect of the CRD-PEG-T7–plasmid DNA complex were examined. RESULTS: The results demonstrated that the CRD-PEG-T7–plasmid DNA complex was nanosized and had a positively charged surface, good cellular uptake efficacy, minimal cytotoxicity, and a dual-targeting effect as compared with the CRD-PEG–plasmid DNA complex. The peptide T7-modifed new delivery system was able to target the highly expressed transferrin receptor (TfR) on tumor cells with an efficiency four-fold higher than that of the non-modified system. CONCLUSION: The results above indicatd that the CRD-PEG-T7–plasmid DNA complex may prove to be a promising gene delivery system targeting bone-metastatic tumor.