Mitophagy suppression via lncRNA H19 silencing: a novel strategy to overcome cisplatin resistance in lung adenocarcinoma.

Cisplatin (DDP) resistance substantially compromises treatment efficacy in lung adenocarcinoma (LUAD). This study investigates the role of mitochondrial long non-coding RNA (lncRNA) H19 in mediating DDP resistance. High-throughput sequencing and RT-qPCR analyses revealed pronounced H19 upregulation in DDP-resistant A549 (A549/DDP) cells relative to parental A549 cells. Subcellular localization studies indicated that H19 is primarily nuclear in A549 cells but translocates to mitochondria in A549/DDP cells. Functional assays demonstrated that H19 silencing in resistant cells attenuated chemoresistance, suppressed proliferation, migration, invasion, and colony formation in vitro, and delayed tumor growth in vivo. H19 knockdown impaired mitophagy and promoted apoptosis, mirroring autophagy inhibition and restoring DDP sensitivity. In contrast, H19 overexpression in A549 cells did not significantly alter mitophagy or cellular behavior. Furthermore, H19 silencing induced its relocalization from mitochondria back to the nucleus in resistant cells, while overexpression did not affect its nuclear localization. These findings establish that H19 translocation to mitochondria promotes DDP resistance, and its downregulation reverses this process by inhibiting mitophagy and resensitizing cells to DDP. As a nucleus-encoded mitochondria-associated lncRNA (ntmtlncRNA), H19 mediates intercompartmental communication, highlighting its potential as a therapeutic target for overcoming DDP resistance in LUAD.