N-methyladenosine-mediated upregulation of LNCAROD confers radioresistance in esophageal squamous cell carcinoma through stabilizing PARP1.

Background: Radiotherapy is a primary therapeutic modality for esophageal squamous cell carcinoma (ESCC), but its effectiveness is still restricted due to the resistance of cancer cells to radiation. Long non-coding RNAs (lncRNAs) and N-methyladenosine (m6A) have been shown to play significant roles in tumour radioresistance. However, the precise manifestation and role of m6A-modified lncRNAs in ESCC radioresistance remain unclear.

Methods: Bioinformatics analysis was conducted to identify m6A-modified lncRNAs implicated in the radioresistance of ESCC. A series of functional experiments were performed to investigate the function of LNCAROD in ESCC. Methylated RNA immunoprecipitation, chromatin isolation by RNA purification-mass spectrometry, RNA immunoprecipitation, and co-immunoprecipitation experiments were performed to explore the mechanism of m6A-mediated upregulation of LNCAROD expression and the downstream mechanism enhancing the radioresistance of ESCC. The efficacy of LNCAROD in vivo was assessed using murine xenograft models.

Results: Herein, we identified LNCAROD as a novel METTL3-mediated lncRNA that enhanced radioresistance in ESCC cells and was post-transcriptionally stabilised by YTHDC1. Moreover, we confirmed that LNCAROD prevented ubiquitin-proteasome degradation of PARP1 protein by facilitating PARP1-NPM1 interaction, thereby contributing to homologous recombination-mediated DNA double-strand breaks repair and enhancing the radiation resistance of ESCC cells. Silencing LNCAROD in a nude mouse model of ESCC in vivo resulted in slower tumour growth and increased radiosensitivity.

Conclusion: Our findings enhance the understanding of m6A-modified lncRNA-driven machinery in ESCC radioresistance and underscore the significance of LNCAROD in this context, thereby contributing to the development of a potential therapeutic target for ESCC patients.