Recombinant Synthesis of Hybrid Lipid–Peptide Polymer Fusions that Self‐Assemble and Encapsulate Hydrophobic Drugs

Abstract

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Elastin-Like Polypeptides for Biomedical Applications

“…Chilkoti and coworkers (93) demonstrated prolonged localization of the radionuclide in a tumor upon intratumoral injection of a 131 I-ELP conjugate that forms a depot in situ because of the phase transition of the conjugate into an insoluble coacervate at a temperature below 37°C. The depot-forming ELP improved drug retention in the tumor by 2.5-fold compared to the soluble ELP fusion and provided more sites for 131 I labeling without reducing the T t below ambient temperature (94). By doubling the ELP chain length, the tumor retention of 131 I-ELP was increased by 14-fold compared to the ELP chain with half the molecular weight; by increasing the injection concentration, the drug retention in the tumor was increased by 5-fold compared to injections of the 131 I-ELP injected at one-sixteenth the concentration.…”

“…The depot-forming ELP improved drug retention in the tumor by 2.5-fold compared to the soluble ELP fusion and provided more sites for 131 I labeling without reducing the T t below ambient temperature (94). By doubling the ELP chain length, the tumor retention of 131 I-ELP was increased by 14-fold compared to the ELP chain with half the molecular weight; by increasing the injection concentration, the drug retention in the tumor was increased by 5-fold compared to injections of the 131 I-ELP injected at one-sixteenth the concentration. The optimal dosing concentration, ELP length, and radionuclide labeling resulted in a 100% survival rate in a xenograft FaDu squamous cell model and in a xenograft PC-3 prostate cancer model in nude mice, with over two-thirds of mice showing complete regression.…”

Site-Selective Protein Modification: From Functionalized Proteins to Functional Biomaterials

“…130,131 As E. coli does not naturally utilize the NMT enzyme, myristoylation was found to be orthogonal to the E. coli proteome. Myristic acid has been installed onto an elastin-like polypeptide to generate temperature-responsive liposomes for doxorubicin and paclitaxel encapsulation, 132 as well as in the synthesis of genetically encoded hybrid self-assembled materials (Figure 11). 133 NMT has also been used to create modified proteins for direct incorporation into biomaterials.…”

Engineered Ribonucleoprotein Granules Inhibit Translation in Protocells

“…ELPs exhibit LCST phase behavior in water; below their cloud point temperature (T CP ) they are soluble, while above their T CP they undergo simple coacervation to form a protein-rich coacervate (Meyer and Chilkoti, 2004). We selected ELPs as our granule-forming IDPs for a number of reasons: (1) their LCST phase behavior has been extensively characterized and can therefore be easily tailored (McDaniel et al, 2013;Meyer and Chilkoti, 2004); (2) they can be produced in large quantities by recombinant expression in Escherichia coli (MacEwan and Chilkoti, 2010); (3) they can be easily fused to other proteins and peptides, and these ELP fusion proteins exhibit temperature triggered coacervation (Christensen et al, 2009(Christensen et al, , 2013Hassouneh et al, 2010;Meyer and Chilkoti, 1999); (4) their chemical diversity and hence function can be expanded upon at the translational level by incorporating unnatural amino acids (Amiram et al, 2015;Costa et al, 2018) and by post-translational modifications (Luginbuhl et al, 2017;Mozhdehi et al, 2018); and (5) we have previously investigated their use as building blocks of model liquid granules within water-in-oil microdroplets (Simon et al, 2017). Here again, we chose to study engineered biomolecular condensates within water-in-oil emulsion droplets, as they provide a discrete, well-defined, and highly uniform microenvironment that is ideal for observing the dynamics of biomolecular condensate formation under precisely controlled in vitro conditions that are challenging to control in vivo.…”