Emerging Adjuvants for Cancer Immunotherapy

Abstract

Cancer is a life-threatening disease, and immunotherapies have been developed as a novel, potent treatment for cancer. Adjuvants, used alone or in combination with other agents, play crucial roles in immune activation. This is necessary for cancer immunotherapy, particularly in the construction of therapeutic cancer vaccines. Adjuvants activate antigen-presenting cells and promote the presentation of antigen epitopes on major histocompatibility complex molecules, further enhancing adaptive immune responses, including cytotoxic T lymphocytes, to elicit cancer-cell death. However, the applications of adjuvants are limited by their poor efficacy or insufficient safety. In recent studies, researchers attempted to develop safe, efficacious adjuvants for cancer immunotherapy, and many compounds (including inorganic compounds, organic molecules, polymers, and colloids) have been identified and optimized as agonists of various pathways. In this review, we focus on the discovery and structural design of emerging adjuvants and discuss how these findings benefit healthcare.

Alum Adjuvant and Built-in TLR7 Agonist Synergistically Enhance Anti-MUC1 Immune Responses for Cancer Vaccine

“…Toll-like receptors (TLRs) are pattern-recognition receptors (PRRs) found in many immune cells such as macrophages and dendritic cells (DCs) (15)(16)(17)(18). TLRs can recognize nucleic acid molecules or cell wall components of pathogens to the innate immune system, and then regulate the activation of antigenpresenting cells (APCs) (19)(20)(21). The purine-rich RNA is a natural ligand for TLR7, which induces the innate immune response to the invading pathogen (22)(23)(24)(25).…”

Immunotherapy as a Precision Medicine Tool for the Treatment of Prostate Cancer

“…Immunotherapies for PCa include both passive treatment approaches, such as direct delivery of monoclonal antibodies (mAbs) with high tumor antigen specificity, and active approaches, such as vaccines. Adjuvants for cancer immunotherapy include organic molecules, inorganic compounds, nanoparticles, polymers, and colloids such as gels, sols, and emulsions, and can be combined with both active and passive forms of immunotherapy with the aim to enhance the immune response [ 46 , 47 ]. Notably, cytokines can be used as adjuvants in combination with other immunotherapeutic agents, as, for example, in tumor cell-based cancer vaccines [ 36 ].…”

Trial watch: intratumoral immunotherapy

“… 11 , 12 At the same time, the evidence came up that some conventional treatments, like anthracycline-based chemotherapy or radiotherapy, 13 , 14 which were initially used to impair cancer cell proliferation, were also able to induce the release of damage-associated molecular patterns (DAMPs) and antigens, leading to the activation of an adaptive anticancer immune response. 15–18 Nowadays, several immunotherapies are being investigated in oncology: vaccines, 19 , 20 adjuvants, 21 , 22 monoclonal antibodies (mAbs), 23 , 24 virotherapy, 25 cytokines, 26 and adoptive cell transfer. 27 , 28 Immune checkpoint inhibitors (ICIs) are a subclass of mAbs neutralizing inhibitory immune signals such as programmed cell death 1 (PDCD1, best known as PD1), CD174 (best known as PDL1), or cytotoxic T lymphocyte-associated protein 4 (CTLA4).…”