Dr. Akansha Singh

Conference 2024 Live Talk

Talk Title

Adrenergic receptor signaling regulates the CD40-receptor mediated anti-tumor immunity

Authors and Affiliations

Akansha Singh, Ashish Ranjan

Department of Radiation Oncology, UT Southwestern Medical Centre, Dallas, Texas, United States

Abstract

Background

Anti-CD40 agonistic antibody (CD40), an activator of dendritic cells (DC) enhances antigen presentation and engagement with its cognate ligand (CD40L) on T cells. Although promising, systemic administration of CD40 in patients is only moderately effective, and its efficacy depends upon the presence of an immunogenic environment and optimal immune priming. Prior research has shown that 2-adrenergic receptor ( 2AR) expressed on DCs decline its functions. Herein, we determined the implications of -adrenergic signaling on DCs activation and maturation mediated by CD40, and whether propranolol, an FDA approved Pan-Beta blocker can improve local CD40 in-situ immunotherapy of poorly immunogenic head and neck tumors (MOC2).

Methods

Unstimulated CD11c+ cells (nDCs) and MOC2 tumor cell lysate stimulated CD11c+ cells (iDCs) from C57BL/6 female mice were exposed to 2-AR agonist (Isoproterenol, ISO; 1M) and CD40 (10ng/ml). Surface expression of MHC-II, CD86 & CD40 using flow cytometry, NFB activation via western blot and expressed cytokine via RT-PCR & ELISA were determined. Mice bearing MOC2 xenograft in flank region were randomized as follows: (1) Untreated control, (2) CD40, (3) Propranolol (Prop; -AR antagonist) & (4) CD40+Prop. Prop (10mg/kg B.W.) was injected intraperitoneally 5 days post tumor inoculation. 30g CD40 was administrated intratumorally twice 8 days apart at an initial volume of ~50mm3. 4-wks post-inoculation, tumors were profiled for immune cell dynamics using flow cytometry.

Results

2-AR signalling with ISO significantly decreased the expressions of MHC-II, CD86 and CD40 on nDCs and iDCs regardless of CD40 treatment. In addition, CD40+ISO decreased intracellular levels of pIkB (NFB activator) compared to CD40 alone. The modification of intracellular signalling correlated with the decrease of pro-inflammatory cytokines (e.g., IL-6, IL-1b) and increase of anti-inflammatory cytokine (IL-10). In the mice model, combining CD40 with Prop significantly suppress MOC2 tumor growth in murine model compared to monotherapies, with the treated tumors demonstrating significantly higher infiltration of CD8+ T cells, CD8+ GZMB+ cytotoxic T cells, activated DCs (MHC-II CD86 and MHC-II CD40 double positive DCs), and reduced populations of CD4+ FOXP+ Treg cells relative to monotherapies.

Conclusions

-adrenergic signaling negatively impacts CD40 induced DCs activation and maturation mediated. Combining CD40 with propranolol reverses the 2AR signalling suppressed anti-tumor immunity, thereby providing the foundational basis for improving CD40 immunotherapy outcomes in patients using -blockers.