title: Modes of action of TLR7 agonists in cancer therapy.
abstract: From the numerous Toll-like receptor agonists, only TLR7 agonists have been approved for cancer treatment, although they are current restricted to topical application. The main target cells of TLR7 agonists are plasmacytoid dendritic cells, producing IFN-α and thus acting on other immune cells. Thereby dendritic cells acquire enhanced costimulatory and antigen-presenting capacity, priming an adaptive immune response. Besides NK cells, antigen-specific T cells are the main terminal effectors of TLR7 agonists in tumor therapy. This qualifies TLR7 agonists as vaccine adjuvants, which is currently being tested in clinical trials. However, the systemic application of TLR7 agonists shows insufficient efficacy, most likely owing to toxicity-limited dosing. The use of TLR7 agonists in combinational therapy holds the promise of synergistic activity and lower required doses.
authors.affiliation: Center of Integrated Protein Science Munich (CIPS-M) & Division of Clinical Pharmacology, Department of Internal Medicine IV, Ludwig-Maximilians-Universität München, Munich, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kobold
authors.forename: Gabriela
authors.initials: G
authors.lastname: Wiedemann
authors.forename: Simon
authors.initials: S
authors.lastname: Rothenfußer
authors.forename: Stefan
authors.initials: S
authors.lastname: Endres
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000276:immunology / Q000494:pharmacology*; D003713:Dendritic Cells / Q000276:immunology; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D009369:Neoplasms / Q000628:therapy*; D051199:Toll-Like Receptor 7 / Q000819:agonists*
chemical_list: D000970:Antineoplastic Agents; C495348:TLR7 protein, human; D051199:Toll-Like Receptor 7
keywords: TLR7; cancer immunotherapy; imiquimod; innate immunity