Long non-coding RNA LRTOR drives osimertinib resistance in non-small cell lung cancer by boosting YAP positive feedback loop.

The therapeutic efficacy of osimertinib (OSI) in EGFR-mutant lung cancer is ultimately limited by the onset of acquired resistance, of which the mechanisms remain poorly understood. Here, we identify a novel long non-coding RNA, LRTOR, as a key driver of OSI resistance in non-small cell lung cancer (NSCLC). Clinical data indicate that elevated LRTOR expression correlates with poor prognosis in OSI-resistant patients. Functionally, LRTOR promotes tumor growth and confers OSI resistance both in vitro and in vivo. Mechanistically, LRTOR shields YAP from LATS-mediated phosphorylation at Ser127 and Ser381, preventing its proteasomal degradation. Furthermore, LRTOR facilitates the interaction between YAP and KCMF1, promoting K63-linked ubiquitination, nuclear translocation of YAP, and formation of the YAP/TEAD1 transcriptional complex, which in turn triggers the transcription of LRTOR, establishing a positive feedback loop that amplifies oncogenic signaling of YAP and consequently induces OSI resistance. LRTOR depletion by siRNA restores OSI sensitivity in resistant tumors, as demonstrated in patient-derived organoid xenograft models. Our findings unveil LRTOR as a central regulator of OSI resistance in NSCLC and propose it as a promising therapeutic and prognostic target for overcoming acquired OSI resistance in EGFR-mutant lung cancer.