Aryl Hydrocarbon Receptor Inhibition Activates Mito-calcium/mtROS/IL-12 Axis in Dendritic Cells to Promote Tumor Suppression 2299915

Introduction IL-12 generated by dendritic cells (DCs) plays a pivotal role in activating an effective anti-tumor response. Specific genetic manipulation of DCs to enhance tumor infiltration and localized IL-12 secretion is an attractive therapeutic strategy for cancer immunotherapy. Methods A genome-wide CRISPR/Cas9 knockout screening identified negative regulators of IL-12 production in bone marrow-derived dendritic cells (BMDCs). Adoptive transfer studies established the role of the Aryl hydrocarbon receptor (AhR) in tumor growth. The immune cell neutralization and two-photon live imaging were employed to determine the effector cells involved in AhR inhibition-induced tumor suppression, and the molecular pathways were explored using bulk RNA sequencing, TEM, and flow cytometry. AhR inhibition in human DCs validated their role in activating tumor-killing effector cells. Results CRISPR/Cas9 screening in BMDCs identified aryl hydrocarbon receptor (AhR) as an important negative regulator of IL-12 production. DC-specific knockout of AhR suppresses tumor growth by promoting the infiltration of IL-12+ DCs and CD107a+ NK1.1+ cells. Antibody blockade studies in MC38-implanted AhRΔDC mice reveal NK cells as the predominant effector cells mediating tumor suppression. AhR inhibition promotes NK cell migration and interaction with TIDC within the TME. AhR-deficient TIDCs enhanced the mtROS production while preserving structure and membrane potential. AhR-deficient DCs sensitized TLR4 signaling and enriched mitochondria-ER contacts (MERCs), which leads to IP3R/VDAC1/MCU-mediated mitochondrial calcium influx, mtROS, and IL-12 production. AhR inhibition in human DCs enhanced tumor-killing function in NK cells in an mtROS/IL-12-dependent manner. Conclusion AhR ablation in DCs releases the inhibitory brake on the IP3R-gated mito-calcium/mtROS/IL-12 axis. This facilitates DC-NK infiltration and crosstalk within the TME. AhR and MERCs could be potential therapeutic targets in DCs for future cancer immunotherapy. Funding Source n/a Topic Categories Classical and Non-Classical Antigen Presenting Cells (APC)