The use of tail-anchored protein chimeras to enhance liposomal cargo delivery

• Published in: PloS one 2019-02, Vol.14 (2), p.e0212701-e0212701
• Main Authors: Abdelrehim, Abbi, Shaltiel, Lior, Zhang, Ling, Barenholz, Yechezkel, High, Stephen, Harris, Lynda K
• Format: Article
• Language: English
• Subjects: Antigenic determinants; Apoptosis; Biology; Biology and Life Sciences; Cells (Biology); Chemical modification; Chimeras; Chimeras (Organisms); Conjugation; Cytochrome; Cytochrome b5; Cytochromes; Cytochromes b5 - chemistry; Cytochromes b5 - genetics; Cytochromes b5 - pharmacology; Displays (Marketing); Drug delivery; Drug delivery systems; Epidermal growth factor; Epidermal growth factors; Epitopes; Gene expression; Genetic aspects; HeLa Cells; Homing; Humans; Insertion; Ligands; Lipids; Liposomes; Medicine; Medicine and Health Sciences; Nanoparticles; Novels; Organic chemistry; Peptides; Pharmacology; Physiological aspects; Placenta; Protein Domains; Proteins; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - pharmacology; Research and Analysis Methods; Therapeutics; Transcription; Tumors
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0212701

Liposomes are employed as drug delivery vehicles offering a beneficial pharmacokinetic/distribution mechanism for in vivo therapeutics. Therapeutic liposomes can be designed to target specific cell types through the display of epitope-specific targeting peptides on their surface. The majority of peptides are currently attached by chemical modification of lipid constituents. Here we investigate an alternative and novel method of decorating liposomes with targeting ligand, using remotely and spontaneously inserting chimeric tail-anchored membrane (TA) proteins to drug loaded liposomes. An artificial TA protein chimera containing the transmembrane domain from the spontaneously inserting TA protein cytochrome b5 (Cytb5) provided a robust membrane tether for the incorporation of three different targeting moieties into preformed liposomes. The moieties investigated were the transactivator of transcription (TAT) peptide, the EGF-receptor binding sequence GE11 and the placental and tumour homing ligand CCGKRK. In all cases, TA protein insertion neither significantly altered the size of the liposomes nor reduced drug loading. The efficacy of this novel targeted delivery system was investigated using two human cell lines, HeLa M and BeWo. Short term incubation with one ligand-modified TA chimera, incorporating the TAT peptide, significantly enhanced liposomal delivery of the encapsulated carboxyfluorescein reporter. The Cytb5 TA was successfully employed as a membrane anchor for the incorporation of the desired peptide ligands into a liposomal drug delivery system, with minimal loss of cargo during insertion. This approach therefore provides a viable alternative to chemical conjugation and its potential to accommodate a wider range of targeting ligands may provide an opportunity for enhancing drug delivery.