Pharmacological rescue of tumor intrinsic STING expression and immune response in LKB1-mutant lung cancer via the IAP-JAK regulatory axis

Abstract

SummaryHarnessing the power of the immune system to treat cancer has become a core clinical approach. However, rewiring of intrinsic circuitry enables tumor cells to escape immune attacks, leading to therapeutic failure. Pharmacological strategies to reverse tumor genotype-dictated therapeutic resistance are urgently needed to advance precision immunotherapy. Here, we identify antagonists of Inhibitor of Apoptosis Protein (IAP) as potent sensitizers that restore immune-dependent killing of LKB1-mutant lung cancer cells. Mechanistic studies reveal an LKB1-IAP-JAK trimolecular complex that bridges the LKB1-mutant genotype with IAP-dependency and a STING-deficiency-mediated immune resistance phenotype. Ultimately, inhibition of IAP re-establishes JAK-regulated STING expression and DNA sensing pathway as well as enhanced cytotoxic immune cell infiltration and selective immune-dependent anti-tumor activity in an LKB1-mutant immune-competent mouse model. Thus, IAP-JAK-modulatory strategies, like IAP inhibitors, offer promising immunotherapy adjuvants to re-establish the responsiveness of “immunologically-cold” LKB1-mutant tumors to immune checkpoint inhibitors or STING-directed therapies.