Delivery of a Cancer-Testis Antigen-Derived Peptide Using Conformationally Restricted Dipeptide-Based Self-Assembled Nanotubes

Abstract

Use of tumor-associated antigens for cancer immunotherapy is limited due to their poor in vivo stability and low cellular uptake. Delivery of antigenic peptides using synthetic polymer-based nanostructures has been actively pursued but with limited success. Peptide-based nanostructures hold much promise as delivery vehicles due to their easy design and synthesis and inherent biocompatibility. Here, we report self-assembly of a dipeptide containing a non-natural amino acid, α,β-dehydrophenylalanine (ΔF), into nanotubes, which efficiently entrapped a MAGE-3-derived peptide (M3). M3 entrapped in F-ΔF nanotubes was more stable to a nonspecific protease treatment and both F-ΔF and F-ΔF-M3 showed no cellular toxicity for four cancerous and noncancerous cell lines used. F-ΔF-M3 showed significantly higher cellular uptake in RAW 267.4 macrophage cells compared to M3 alone and also induced in vitro maturation of dendritic cells (DCs). Immunization of mice with F-ΔF-M3 selected a higher number of IFN-γ secreting CD8+ T cells and CD4+ T compared to M3 alone. On day 21, a tumor growth inhibition ratio (TGI, %) of 41% was observed in a murine melanoma model. These results indicate that F-ΔF nanotubes are highly biocompatible, efficiently delivered M3 to generate cytotoxic T lymphocytes responses, and able to protect M3 from degradation under in vivo conditions. The F-ΔF dipeptide-based nanotubes may be considered as a good platform for further development as delivery agents.

Chemically Modified Dipeptide Based Hydrogel Supports Three-Dimensional Growth and Functions of Primary Hepatocytes

“…The morphologies of 1 wt % Dp gel and LEM 1 -Dp matrix were analyzed using the 120 kV mode of TEM (Tecnai 12 BioTWIN, FEI Netherlands), micrographs were taken using Analysis II (Megaview, SIS, Germany) software, and the detailed experimental procedure has been described earlier. , …”

“…Scanning electron microscope imaging (Carl Zeiss, Model EVO LS10) of LEM 1 -Dp matrix treated with Huh7 cells and pHCs culture supernatant (37 °C, 7 days) was used to monitor morphological changes in the gel structure as described earlier. , …”

“…The morphologies of 1 wt % Dp gel and LEM 1 -Dp matrix were analyzed using the 120 kV mode of TEM (Tecnai 12 BioTWIN, FEI Netherlands), micrographs were taken using Analysis II (Megaview, SIS, Germany) software, and the detailed experimental procedure has been described earlier. 30,38 The microstructural features of the 1 wt % Dp gel and LEM 1 -Dp matrix were determined using SEM, and images were acquired using a Carl Zeiss scanning electron microscope (Model EVO LS10). SEM was equipped with a lanthanum hexaboride emitting cathode and SmartSEM operating software.…”

“…We have previously shown that the introduction of ΔF in the peptide sequence confers conformational constraints in the peptide backbone and induce proteolytic stability. We have also shown that dipeptides consisting of α,β-dehydrophenylalanine (ΔF) at their carboxyl terminal readily formed a variety of stable nanosized structures such as spherical, tubular, and fibrillar structures. − …”

Conformationally Restricted Dipeptide-Based Nanoparticles for Delivery of siRNA in Experimental Liver Cirrhosis

“…Short peptide-based nanostructures (2–5 residues) have gained more attention owing to their simple structure, ease of synthesis, low cost, and, above all, high biocompatibility. , However, the susceptibility of peptide-based systems to enzymatic degradation remains a hurdle in their clinical development . Ultrashort peptide-based nanostructures containing a chemically modified amino acid, α,β-dehydrophenylalanine (ΔF) residue, have been shown to self-assemble into various nanostructures with characteristic shapes and sizes. − The presence of ΔF in peptide sequences induces conformational restriction as well as resistance to enzymatic degradation. , Dipeptides containing ΔF have been successfully utilized for the delivery of drugs, antigens, and oligonucleotides in in vitro and in vivo conditions. − …”