Functional L-Arginine Derivative as an Efficient Vector for Intracellular Protein Delivery for Potential Cancer Therapy.

The utilization of cytosolic protein delivery is a promising approach for treating various diseases by replacing dysfunctional proteins. Despite the development of various nanoparticle-based intracellular protein delivery methods, the complicated chemical synthesis of the vector, loading efficiency and endosomal escape efficiency of proteins remain a great challenge. Recently, 9-fluorenylmethyloxycarbonyl (Fmoc)-modified amino acid derivatives have been used to self-assemble into supramolecular nanomaterials for drug delivery. However, the instability of the Fmoc group in aqueous medium restricts its application. To address this issue, the Fmoc ligand neighboring arginine was substituted for dibenzocyclooctyne (DBCO) with a similar structure to Fmoc to obtain stable DBCO-functionalized L-arginine derivative (DR). Azide-modified triethylamine (crosslinker C) was combined with DR to construct self-assembled DRC via a click chemical reaction for delivering various proteins, such as BSA and saporin (SA), into the cytosol of cells. The hyaluronic-acid-coated DRC/SA was able to not only shield the cationic toxicity, but also enhance the intracellular delivery efficiency of proteins by targeting CD44 overexpression on the cell membrane. The DRC/SA/HA exhibited higher growth inhibition efficiency and lower IC50 compared to DRC/SA toward various cancer cell lines. In conclusion, DBCO-functionalized L-arginine derivative represents an excellent potential vector for protein-based cancer therapy.

Recent Progress of Rational Modified Nanocarriers for Cytosolic Protein Delivery.

Therapeutic proteins garnered significant attention in the field of disease treatment. In comparison to small molecule drugs, protein therapies offer distinct advantages, including high potency, specificity, low toxicity, and reduced carcinogenicity, even at minimal concentrations. However, the full potential of protein therapy is limited by inherent challenges such as large molecular size, delicate tertiary structure, and poor membrane penetration, resulting in inefficient intracellular delivery into target cells. To address these challenges and enhance the clinical applications of protein therapies, various protein-loaded nanocarriers with tailored modifications were developed, including liposomes, exosomes, polymeric nanoparticles, and nanomotors. Despite these advancements, many of these strategies encounter significant issues such as entrapment within endosomes, leading to low therapeutic efficiency. In this review, we extensively discussed diverse strategies for the rational design of nanocarriers, aiming to overcome these limitations. Additionally, we presented a forward-looking viewpoint on the innovative generation of delivery systems specifically tailored for protein-based therapies. Our intention was to offer theoretical and technical support for the development and enhancement of nanocarriers capable of facilitating cytosolic protein delivery.

Self-assembled D-arginine derivatives based on click chemical reactions for intracellular codelivery of antigens and adjuvants for potential immunotherapy.

Self-assembled amino acid derivatives could form well-defined nanostructures which have great application value for drug delivery systems. In particular, D-amino acid derivatives possess tremendous advantages including anti-degradation and good lysosome escape compared with L-amino acid derivatives. In this work, 9-fluorenylmethyloxycarbonyl (Fmoc) neighboring D-arginine derivatives were replaced by dibenzocyclooctyne (DBCO) to extend the class of functional D-arginine derivatives, which were further reacted with various cross-linkers including azide to construct a library of self-assembled supramolecular nanovehicles and strengthen the stability of nanostructures for disease immunotherapy. Moreover, in vitro studies demonstrated that the combination of DBCO modified D-arginine derivative DR3 and cross-linker C1 not only reinforced the cellular uptake efficiency of ovalbumin (OVA) which was chosen as the model antigen, but also promoted the cytokine TNF-α release of RAW 264.7 cells after the introduction of adjuvant unmethylated cytosine-phosphate-guanine dinucleotides (CpG). Furthermore, the nanovaccine based on DR3C1 could enhance the antigen OVA and adjuvant cytosolic delivery of marrow derived dendritic cells (BMDCs), which improved the antigen-presentation cross efficiency and induced the maturation of BMDCs. Taken together, we believe that D-arginine derivatives functionalized by DBCO provide an effective strategy for disease immunotherapy and act as a great potential delivery tool.