Evaluation of a Synergistic Effect of L-Arginine on the Anticancer Activity of Doxorubicin by Using a Co-culture System

Triggering the nanophase separation of albumin through multivalent binding to glycogen for drug delivery in 2D and 3D multicellular constructs

Engineered nanoparticles for the encapsulation of bioactive agents hold promise to improve disease diagnosis, prevention and therapy. To advance this field and enable clinical translation, the rational design of nanoparticles with controlled functionalities and a robust understanding of nanoparticle-cell interactions in the complex biological milieu are of paramount importance. Herein, a simple platform obtained through the nanocomplexation of glycogen nanoparticles and albumin is introduced for the delivery of chemotherapeutics in complex multicellular 2D and 3D systems. We found that the dendrimer-like structure of aminated glycogen nanoparticles is key to controlling the multivalent coordination and phase separation of albumin molecules to form stable glycogen-albumin nanocomplexes. The pH-responsive glycogen scaffold conferred the nanocomplexes the ability to undergo partial endosomal escape in tumour, stromal and immune cells while albumin enabled nanocomplexes to cross endothelial cells and carry therapeutic agents. Limited interactions of nanocomplexes with T cells, B cells and natural killer cells derived from human blood were observed. The nanocomplexes can accommodate chemotherapeutic drugs and release them in multicellular 2D and 3D constructs. The drugs loaded on the nanocomplexes retained their cytotoxic activity, which is comparable with the activity of the free drugs. Cancer cells were found to be more sensitive to the drugs in the presence of stromal and immune cells. Penetration and cytotoxicity of the drug-loaded nanocomplexes in tumour mimicking tissues were validated using a 3D multicellular-collagen construct in a perfusion bioreactor. The results highlight a simple and potentially scalable strategy for engineering nanocomplexes made entirely of biological macromolecules with potential use for drug delivery.

Preparation of a PEGylated liposome that co-encapsulates l-arginine and doxorubicin to achieve a synergistic anticancer effect

Strategies that combine chemotherapies with unconventional agents such as nitric oxide (NO) have been shown to enhance cancer therapies. Compared with small molecule chemotherapy drugs, nanosized particles have improved therapeutic efficacies and reduced systemic side effects because of the enhanced permeability and retention effect. In this report, we prepared PEGylated liposomes (LP) that incorporated l-arginine (Arg) and the anticancer drug doxorubicin (Dox) to yield a co-delivery system (Dox–Arg-LP). On the basis of our previous research, we hypothesized that Dox–Arg-LP should achieve a synergistic anticancer effect because Arg conversion to NO by activated M1 macrophages augments the chemotherapeutic activity of Dox. Dox–Arg-LP showed comparable physical properties to those of conventional Dox-only liposomes (Dox-LP). In vitro assessment revealed that the cytotoxicity of Dox–Arg-LP toward cancer cells was significantly higher than that of Dox-LP. In vivo application of Dox–Arg-LP in mice enhanced the chemotherapeutic effect with a 2 mg kg⁻¹ dose of Dox–Arg-LP achieving the same therapeutic efficacy as a two-fold higher dose of Dox-LP (i.e., 4 mg kg⁻¹). Therefore, co-encapsulation of dual agents into a liposome formulation is an efficient strategy to enhance chemotherapy while reducing systemic toxicity.

Strategies that combine chemotherapies with unconventional agents such as nitric oxide (NO) have been shown to enhance cancer therapies.