Cys34-PEGylated Human Serum Albumin for Drug Binding and Delivery

Abstract

Polyethylene glycol (PEG) derivatives were conjugated onto the Cys-34 residue of human serum albumin (HSA) to determine their effects on the solubilization, permeation, and cytotoxic activity of hydrophobic drugs such as paclitaxel (PTX). PEG(C34)HSA conjugates were prepared on a multigram scale by treating native HSA (n-HSA) with 5- or 20-kDa mPEG-maleimide, resulting in up to 77% conversion of the mono-PEGylated adduct. Nanoparticle tracking analysis of PEG(C34)HSA formulations in phosphate buffer revealed an increase in nanosized aggregates relative to n-HSA, both in the absence and presence of PTX. Cell viability studies conducted with MCF-7 breast cancer cells indicated that PTX cytotoxicity was enhanced by PEG(C34)HSA when mixed at 10:1 mole ratios, up to a two-fold increase in potency relative to n-HSA. The PEG(C34)HSA conjugates were also evaluated as PTX carriers across monolayers of HUVEC and hCMEC/D3 cells, and found to have nearly identical permeation profiles as n-HSA.

Transthyretin Exerts Pro-Apoptotic Effects in Human Retinal Microvascular Endothelial Cells Through a GRP78-Dependent Pathway in Diabetic Retinopathy

“…The only cysteine in TTR is located at the N-terminus, therefore, TTR could be site-specifically labeled at this cysteine with N-(5-Fluoresceinyl) maleimide as previously reported [21,22]. The purified TTR was incubated with 5 mM DTT in 20 mM Tris-HCl (pH 8.0) at 4 °C for 2 h, and then, to remove the DTT, the protein was precipitated and washed with 75% (NH 4 ) 2 SO 4 at 4 °C.…”

PEGylated Cationic Serum Albumin for Boosting Retroviral Gene Transfer

“…Additionally, thiol or azide groups have been introduced at the periphery of BSA, allowing bioconjugation with maleimide‐functionalized or alkyne‐terminated PEG in a random fashion. HSA and BSA each offer a single free thiol group that facilitates a single modification, and HSA has been accordingly site‐specifically modified with maleimide‐PEG . Alternatively, solid‐phase immobilization has been used to attach a single NHSactivated PEG chain to HSA immobilized on an anion‐exchange resin .…”

“…HSA and BSA each offer asingle free thiol group that facilitates as ingle modification,a nd HSA has been accordingly site-specifically modifiedw ith maleimide-PEG. [27] Alternatively,s olidphase immobilization has been used to attach as ingle NHS-activatedP EG chain to HSA immobilized on an anion-exchange resin. [21] In addition, noncovalent conjugation of PEG chains to BSA through hexadecylamine, which binds to the hydrophobic pockets of albumin, has been achieved previously.…”

Self‐Assembling Proteins for Design of Anticancer Nanodrugs

“…1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 on the properties of nanodrugs based on self-assembly of PTX and HSA, the PEGylation of HSA with PEG-maleimide was reported. [50] The resulting PEGylated HSA was mixed with 10 equivalents of PTX to form PEGylated nanodrugs. Nanoparticle tracking analysis showed that the distribution of the PEGylated nanodrugs was narrower than that of the nanodrugs based on native HSA and PTX.…”