LncRNA HAR1A inhibits non-small cell lung cancer growth by downregulating c-MYC transcripts and facilitating its proteasomal degradation

Non-small cell lung cancer (NSCLC) is a primary cause of cancer-related mortality on a global scale. Research increasingly shows that long non-coding RNAs (lncRNAs) play crucial regulatory roles and serve as biomarkers for diagnosis, prognosis, therapy monitoring, and druggable targets in NSCLC. We previously identified HAR1A as a tumor-suppressing lncRNA in NSCLC, with its loss also observed in oral and hepatocellular carcinoma. This study aimed to expand the understanding of the functional role of HAR1A in NSCLC and uncover its underlying mechanisms. Our results demonstrated that elevating HAR1A levels impeded NSCLC cell proliferation and migration but promoted apoptosis, thereby boosting their susceptibility to cisplatin. Subsequently, we discovered that HAR1A enhanced cisplatin's cytotoxicity in NSCLC cells by curbing adaptive autophagy through the downregulation of MYC. Further analysis revealed that HAR1A suppresses MYC by both lowering its transcript levels and promoting protein ubiquitination and degradation, thereby restricting tumor cell proliferation, migration, and adaptive autophagy. In exploring MYC's targets, we observed that MYC upregulated the transcription of heat shock protein 90 alpha family class B member 1 (HSP90AB1/HSP90β) gene. Rescue experiments verified that HAR1A mitigated NSCLC cell proliferation and migration and induced apoptosis through the MYC/HSP90β axis. Finally, we confirmed that HAR1A overexpression increased cisplatin efficacy in nude mouse NSCLC xenograft models.In conclusion, the findings suggest that HAR1A could be a promising therapeutic target in treating NSCLC and biomarkers for predicting chemotherapy outcomes. This study provides new insights into the molecular mechanisms of chemoresistance in NSCLC and underscores the potential of lncRNA-based strategies in cancer therapy.