An Albumin-Oligonucleotide Assembly for Potential Combinatorial Drug Delivery and Half-Life Extension Applications

Abstract

The long blood circulatory property of human serum albumin, due to engagement with the cellular recycling neonatal Fc receptor (FcRn), is an attractive drug half-life extension enabling technology. This work describes a novel site-specific albumin double-stranded (ds) DNA assembly approach, in which the 3′ or 5′ end maleimide-derivatized oligodeoxynucleotides are conjugated to albumin cysteine at position 34 (cys34) and annealed with complementary strands to allow single site-specific protein modification with functionalized ds oligodeoxynucleotides. Electrophoretic gel shift assays demonstrated successful annealing of complementary strands bearing Atto488, 6-carboxyfluorescein (6-FAM), or a factor IXa aptamer to the albumin-oligodeoxynucleotide conjugate. A fluorometric factor IXa activity assay showed retained aptamer inhibitory activity upon assembly with the albumin and completely blocked factor IXa at a concentration of 100 nM for 2 hr. The assembled construct exhibited stability in serum-containing buffer and FcRn engagement that could be increased using an albumin variant engineered for higher FcRn affinity. This work presents a novel albumin-oligodeoxynucleotide assembly technology platform that offers potential combinatorial drug delivery and half-life extension applications.

Harnessing albumin as a carrier for cancer therapies

“…The benefits to this covalent method include avoiding use of albumin’s free thiol which is not always available, and the presence of multiple lysine groups available during exogenous conjugation. However, Kuhlmann et al suggest that, although this method allows for the conjugation to multiple lysines, the absence of selectivity may compromise FcRn engagement and consequent albumin pharmacokinetics [94]. Additionally, it may be more difficult to control the number of modifications per albumin as well as site specificity.…”

Structural and Functional Stability of DNA Nanopores in Biological Media

“…Serum proteins cause aggregation most likely due to complexation towards the DNA’s negatively charged phosphate backbone. Albumin serum proteins have been shown to complex to antisense oligonucleotides, which in some instances enhances the half-life of intravenously injected DNA [61,62]. However, hydrophobic groups can further increase the protein complexation extent [63].…”

Aptamers: A Review of Their Chemical Properties and Modifications for Therapeutic Application

“…HSA has a single free thiol at position 34 (cys34). Focusing on these properties, Kuhlmann et al elongated the serum circulation of an aptamer [57]. They utilized the cys34 residue to conjugate an oligonucleotide to HAS, and then the aptamer was hybridized on it.…”