Prospects for the Use of Metal-Based Nanoparticles as Adjuvants for Local Cancer Immunotherapy

Abstract

Immunotherapy is among the most effective approaches for treating cancer. One of the key aspects for successful immunotherapy is to achieve a strong and stable antitumor immune response. Modern immune checkpoint therapy demonstrates that cancer can be defeated. However, it also points out the weaknesses of immunotherapy, as not all tumors respond to therapy and the co-administration of different immunomodulators may be severely limited due to their systemic toxicity. Nevertheless, there is an established way through which to increase the immunogenicity of immunotherapy—by the use of adjuvants. These enhance the immune response without inducing such severe adverse effects. One of the most well-known and studied adjuvant strategies to improve immunotherapy efficacy is the use of metal-based compounds, in more modern implementation—metal-based nanoparticles (MNPs), which are exogenous agents that act as danger signals. Adding innate immune activation to the main action of an immunomodulator makes it capable of eliciting a robust anti-cancer immune response. The use of an adjuvant has the peculiarity of a local administration of the drug, which positively affects its safety. In this review, we will consider the use of MNPs as low-toxicity adjuvants for cancer immunotherapy, which could provide an abscopal effect when administered locally.

The quest for nanoparticle-powered vaccines in cancer immunotherapy

“…Moreover, AuNPs can promote the function of T lymphocytes and enhance antitumor immunity by cross-presenting antigens [ 220 ]. These remarkable characteristics position AuNPs as good candidates for cancer vaccine treatments [ 215 , 218 , 221 , 222 ].…”

Tumor microenvironment responsive metal nanoparticles in cancer immunotherapy

“…It is reported that metal nanoparticles are capable of preventing sudden drug release and avoiding off-target effects, which gives it many advantages such as improved pharmacokinetic properties and flexible control of drug release ( 13 , 14 ). Moreover, several studies have shown that metal nanoparticles, modulated by surface ligands or intrinsic properties, can respond to the unique chemical properties of TME by precisely delivering immunomodulatory factors to target tissues or specific immune cells, to achieve an effective and enhanced immune response for enhanced therapeutic efficacy ( 15 – 17 ). Recently, there are a large number of metal nanoparticles have been developed, such as gold, silver, copper, bismuth, manganese, iron, platinum and lead, which can be applied in various modalities of cancer therapy in different forms such as antibodies, solids and coatings ( 18 – 21 ).…”