Figure 3. LNPs coated with FR-β-antibody target the STING agonist, cGAMP, to PV TAMs and delay CR in ADT-treated Myc-CaP tumors. (A) Design of LNPs used in vivo. The Fc regions of either a FR-β antibody or a control IgG were attached to LNPs containing either an active cGAMP or an inactive version of this (“cGAMP Ctrl”). (B) Tumor growth in mice administered either PBS or ADT alone, or these followed by administration every 2 days of the various forms of LNP listed. (C and D) Various key groups have been selected from (B) and shown separately (for clarity). (C) Tumor growth curves in response to PBS alone (control) versus a single dose of ADT or (D) PBS alone (control), ADT alone, ADT plus FR-β antibody-coated LNPs containing either cGAMP or cGAMP Ctrl. (E) Effect of in vivo administration of (i) an antibody against CD8 or (ii) an isotype-matched control IgG2b on tumor-infiltrating CD8+T cells after ADT plus FR-β antibody-coated LNPs containing cGAMP (magnification bar=50 µm). (iii) Tumor growth curves showing the effect of depleting CD8+T cells on tumor responses to ADT plus by FR-β antibody-coated LNPs containing cGAMP. Data are presented as means±SEMs. *p<0.001 (comparing tumor sizes at sacrifice). ADT, androgen deprivation therapy; LNP, lipid nanoparticle; TAM, tumor-associated macrophage.