Long noncoding RNA AFAP1-AS1 aggravates immunotherapy resistance in NSCLC by enhancing JAK2 and TYK2 translation.

[BACKGROUND] Lung cancer is the most common and deadliest malignancy worldwide, with about 85% of cases being non-small cell lung cancer (NSCLC). Although targeting PD-1/PD-L1 with immune checkpoint inhibitors has revolutionized NSCLC treatment, a substantial proportion of patients still experience intrinsic or acquired resistance. Understanding the mechanisms of immune evasion and resistance and identifying novel therapeutic targets remain critical challenges.

[METHODS] Using RNA sequencing, qRT-PCR, and Western blotting, we discovered and validated that the long non-coding RNA (lncRNA) AFAP1-AS1 activates the interferon signaling pathway and upregulates PD-L1 and IDO1 expression in NSCLC cells. Through mass spectrometry analysis combined with Western blotting and sucrose density gradient separation of polyribosomes, it was found that AFAP1-AS1 binds to the translation initiation factor EIF4A1 and promotes the translation of the tyrosine kinases JAK2 and TYK2. In vitro, CD8 T cell killing ability after coculture was assessed by flow cytometry. In a mouse subcutaneous tumor model, the immunotherapeutic efficacy of JAK2/TYK2 inhibitors and a PD-1 monoclonal antibody against AFAP1-AS1-overexpressing tumors was evaluated.

[RESULTS] In this study, we demonstrate that elevated AFAP1-AS1 expression correlates with poor response to anti-PD-1 therapy and is inversely associated with CD8 T-cell infiltration. Mechanistically, AFAP1-AS1 interacts with EIF4A1 to enhance the translation of JAK2 and TYK2, thereby promoting STAT1 phosphorylation and nuclear translocation, which activate interferon signaling pathways. This cascade upregulates the immunosuppressive checkpoints PD-L1 and IDO1, ultimately suppressing CD8 T cell cytotoxicity and promoting T cell apoptosis. Importantly, in preclinical models, pharmacological inhibition of JAK2 and TYK2 synergistically enhances the efficacy of anti-PD-1 immunotherapy.

[CONCLUSIONS] Our findings reveal a novel mechanism through which AFAP1-AS1 promotes immunotherapy resistance in NSCLC by binding to the translation initiation factor EIF4A1 to enhance JAK2 and TYK2 translation. This highlights AFAP1-AS1 and its downstream tyrosine kinases, JAK2/TYK2, as potential therapeutic targets to improve immunotherapy efficacy in NSCLC.