Construction of arsenic-metal complexes loaded nanodrugs for solid tumor therapy: A mini review

Arsenic trioxide (As₂O₃), a front-line therapeutic agent against acute promyelocytic leukemia, has a broad spectrum against malignancies. Unfortunately, the clinical application of As₂O₃ in treating hematological cancers has not been transformed to solid tumors, for its dose-limited toxicity and undesirable pharmacokinetics. The ordinary As₂O₃ loaded nanodrugs (such as liposomes, polymer micelles, albumin-based nanodrugs, and silica-based nanodrugs, etc.) still could not fuel up pharmaceuticals and eradicate toxicity for low delivery efficiency caused by the instability and severe drug leakage of formulations during circulation. Recently, the approach of forming and delivering arsenic-metal complexes which will dissociate in the tumoral environment caught our mind. This is the most effective strategy to reduce drug leakage in circulation and accumulate arsenite ions in tumor sites, therefore promote the anti-tumor effect and lighten the toxicity of the drug. This review aims to explain the formation mechanism of arsenic-metal nanocomposites and summarize the constructing strategies of the arsenic-metal nanocomplexes (arsenic-nickel, arsenic-manganese, arsenic-platinum, arsenic-gadolinium, arsenic-zinc, and arsenic-iron nanobins) loaded nanodrugs for solid tumor therapy. Furthermore, the expectations and challenges of arsenic-metal complexes containing nanodrugs for cancer therapy in the future were discussed.