Tumor cell intrinsic type I interferon signaling dictates CD47-SIRPa blockade immunotherapy via metabolic reprograming [dataset 2]
Type I interferons (IFN-Is) have been well recognized for their roles in immune cells in tumor immunotherapy. However, their direct effects on tumor cells are less understood. Oxidative phosphorylation (OXPHOS) is typically latent in tumor cells. However, whether OXPHOS can be targeted for immunotherapy remains unclear. Here, we found that tumor cell responsiveness to IFN-Is is essential for CD47-SIRPa blockade immunotherapy. Interestingly, IFN-Is directly reprogram tumor cell metabolism by activating OXPHOS for ATP production via ISG15. ATP extracellular release is also enhanced by IFN-Is via autophagy. Tumor cells with a genetic deficiency in OXPHOS or autophagy were resistant to CD47-SIRPa blockade. ATP released upon CD47-SIRPa blockade primes the anti-tumor T cell response via ATP-P2X7 receptor-mediated dendritic cell activation. Further combination with inhibitors of ATP-degrading ectoenzymes, CD39 and CD73, showed synergistic anti-tumor effects. Together, these data reveal the unrecognized mechanisms of IFN-Is on tumor cell metabolic reprograming in tumor immunotherapy and provide novel strategies harnessing this pathway for enhanced efficacy of CD47-SIRPa blockade. Overall design: MC38 cells were seeded into 6-well plates and inoculated with or without 1 µg/mL recombinant IFN-a. After 6, 24, and 48 h, the cells were harvested for the generation of RNA-seq. libraries.