Conjugate of Doxorubicin to Albumin‐Binding Peptide Outperforms Aldoxorubicin

Abstract

Short circulation time and off‐target toxicity are the main challenges faced by small‐molecule chemotherapeutics. To overcome these shortcomings, an albumin‐binding peptide conjugate of chemotherapeutics is developed that binds specifically to endogenous albumin and harnesses its favorable pharmacokinetics and pharmacodynamics for drug delivery to tumors. A protein‐G‐derived albumin‐binding domain (ABD) is conjugated with doxorubicin (Dox) via a pH‐sensitive linker. One to two Dox molecules are conjugated to ABD without loss of aqueous solubility. The albumin‐binding ABD–Dox conjugate exhibits nanomolar affinity for human and mouse albumin, and upon administration in mice, shows a plasma half‐life of 29.4 h, which is close to that of mouse albumin. Additionally, 2 h after administration, ABD–Dox exhibits an approximately 4‐fold higher concentration in the tumor than free Dox. Free Dox clears quickly from the tumor, while ABD–Dox maintains a steady concentration in the tumor for at least 72 h, so that its relative accumulation at 72 h is ≈120‐fold greater than that of free Dox. The improved pharmacokinetics and biodistribution of ABD–Dox result in enhanced therapeutic efficacy in syngeneic C26 colon carcinoma and MIA PaCa‐2 pancreatic tumor xenografts, compared with free Dox and aldoxorubicin, an albumin‐reactive Dox prodrug currently in clinical development.

Site-specific C-terminal dinitrophenylation to reconstitute the antibody Fc functions for nanobodies

“…Design, synthesis and characterization of nanobody 7D12-DNP conjugates Nanobody 7D12, which recognizes human epidermal growth factor receptor (EGFR) expressed by many tumors, such as A431 cells, 38 was utilized as a model to prove our concept. The wellestablished Sortase-A (SrtA)-mediated ligation (SML) method [39][40][41][42][43][44] was used for the site-specic modication of nanobody 7D12 with DNP. SrtA is a bacterial enzyme that recognizes a specic peptide motif, LPXTG (X can be any amino acid except for cysteine), known as the sorting signal, at the protein C-terminus and cleaves the peptide bond between threonine and glycine to form a thioester intermediate, which is followed by reacting with substrates containing oligoglycine to provide the ligation product.…”

Recombinant Fusion of Glucagon‐Like Peptide‐1 and an Albumin Binding Domain Provides Glycemic Control for a Week in Diabetic Mice

“…For GLP1‐HL‐ABD‐ELP 1 and GLP1‐US‐ABD‐ELP 1 , the ITC cycles were done as described in ref. [39]. Following two ITC cycles, fusion proteins were dialyzed into Milli‐Q water, lyophilized and stored at −20 °C.…”

Recent trends in protein and peptide-based biomaterials for advanced drug delivery

“…One such approach exploits sortase mediated ligation that relies on the specificity of the transpeptidase Sortase A (SrtA) for short peptide sequences. SrtA retains its specificity while accepting a wide range of potential substrates [ [58] , [59] , [60] , [61] ].…”

“…Furthermore, the same group took advantage of the native sortase reaction to directly install DOX onto the ABD (ABD-DOX) through a pH-sensitive linker, without forming nanoparticles [ 59 ]. ABD-DOX bound to both human and mouse serum albumin with nanomolar affinity, had a terminal t 1/2 of 29.4 h in mice, and increased tumor accumulation by ~120 fold compared to free DOX ( Fig.…”

“…Drug-containing monomer (drug: panobinostat, dark blue) was copolymerized with HPMA using RAFT agents, which allow one-step conjugation of albumin. Adapted with permission from [ 59 ] (A) and [ 172 ] (B). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)…”