Itaconate transporter SLC13A3 impairs tumor immunity via endowing ferroptosis resistance

Immune checkpoint blockade (ICB) triggers tumor ferroptosis. However, most patients are unresponsive to ICB. Tumors might evade ferroptosis in the tumor microenvironment (TME). Here, we discovered SLC13A3 is an itaconate transporter in tumor cells and endows tumor ferroptosis resistance, diminishing tumor immunity and ICB efficacy. Mechanistically, tumor cells uptake itaconate via SLC13A3 from tumor-associated macrophages (TAMs), thereby activating the NRF2-SLC7A11 pathway and escaping from immune-mediated ferroptosis. Structural modeling and molecular docking analysis identified a functional inhibitor for SLC13A3 (SLC13A3i). Deletion of ACOD1 (an essential enzyme for itaconate synthesis) in macrophages, genetic ablation of SLC13A3 in tumors, or treatment with SLC13A3i sensitized tumors to ferroptosis, curbed tumor progression, and bolstered ICB effectiveness. Thus, we identify the interplay between tumors and TAMs via the SLC13A3-itaconate-NRF2-SLC7A11 axis as a previously unknown immune ferroptosis resistant mechanism in the TME and SLC13A3 as a promising immunometabolic target and disease indication for treating SLC13A3+cancer. Overall design: Samples were fixed and dissociated using the Miltenyi Octo MACS according to 10X Demonstrated Protocol #CG000553. Dissociated cells were counted on Luna Fx7 (Logos Biosystems). Probes were hybridized, and samples were pooled and processed according to manufacturer instructions for 10X Genomics Chromium Fixed RNA Profiling Reagent Kits for Multiplexed Samples (PN 1000568). Final library quality was assessed using the Lab Chip GXII HT (PerkinElmer), and libraries were quantified by Qubit (Thermo Fisher). Pooled libraries were subjected to paired-end sequencing according to the manufacturer's protocol (Illumina Nova-Seq X Plus). BCL Convert Software (Illumina) was used to generate de-multiplexed Fastq files, and the Cell Ranger Pipeline (10X Genomics) was used to align reads and generate count matrices.