Peptides of pHLIP family for targeted intracellular and extracellular delivery of cargo molecules to tumors.

Abstract

The pH (low) insertion peptides (pHLIPs) target acidity at the surfaces of cancer cells and show utility in a wide range of applications, including tumor imaging and intracellular delivery of therapeutic agents. Here we report pHLIP constructs that significantly improve the targeted delivery of agents into tumor cells. The investigated constructs include pHLIP bundles (conjugates consisting of two or four pHLIP peptides linked by polyethylene glycol) and Var3 pHLIPs containing either the nonstandard amino acid, γ-carboxyglutamic acid, or a glycine-leucine-leucine motif. The performance of the constructs in vitro and in vivo was compared with previous pHLIP variants. A wide range of experiments was performed on nine constructs including (i) biophysical measurements using steady-state and kinetic fluorescence, circular dichroism, and oriented circular dichroism to study the pH-dependent insertion of pHLIP variants across the membrane lipid bilayer; (ii) cell viability assays to gauge the pH-dependent potency of peptide-toxin constructs by assessing the intracellular delivery of the polar, cell-impermeable cargo molecule amanitin at physiological and low pH (pH 7.4 and 6.0, respectively); and (iii) tumor targeting and biodistribution measurements using fluorophore-peptide conjugates in a breast cancer mouse model. The main principles of the design of pHLIP variants for a range of medical applications are discussed.

• Authors: Linden C Wyatt, Anna Moshnikova, Troy Crawford, Donald M Engelman, Oleg A Andreev, Yana K Reshetnyak
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 115 Issue 12 Pg. E2811-E2818 (03 20 2018) ISSN: 1091-6490 [Electronic] United States
• PMID: 29507241 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Amanitins
• Antineoplastic Agents
• Lipid Bilayers
• Liposomes
• Membrane Proteins
• Peptides
• pHLIP protein
• Polyethylene Glycols

Topics

• Amanitins (chemistry)
• Animals
• Antineoplastic Agents (administration & dosage, chemistry)
• Circular Dichroism
• Drug Delivery Systems (methods)
• Female
• HeLa Cells
• Humans
• Hydrogen-Ion Concentration
• Lipid Bilayers (chemistry)
• Liposomes (chemistry)
• Membrane Proteins (chemistry, genetics)
• Mice, Inbred BALB C
• Neoplasms, Experimental (drug therapy)
• Peptides (administration & dosage, chemistry, pharmacokinetics)
• Polyethylene Glycols (chemistry)
• Tissue Distribution