KDM5B/H3K4me3-mediated METTL14 regulates the function of LINC02747 through N6-methyladenosine modification in non-small cell lung cancer

Abstract

Background Multiple epigenetic regulatory mechanisms exert critical roles in tumour development, understanding the interactions and impact of diverse epigenetic modifications on gene expression in cancer is crucial for the development of precision medicine. The main objective of this study was to elucidate the intricate crosstalk between N6-methyladenosine (m6A) modification and histone modification in the context of non-small cell lung cancer (NSCLC). Results Bioinformatics analyses and experiments confirmed that the m6A methyltransferase METTL14 was significantly downregulated in NSCLC tissues, with lower levels correlating with poorer overall survival. Functional experiments demonstrated that overexpression of METTL14 inhibited the proliferation and migration of NSCLC cells both in vivo and in vitro, and the colorimetric m6A quantification assay also showed that knockdown of METTL14 notably reduced global m6A modification levels in NSCLC cells. We confirmed using MeRIP-qPCR and dual-luciferase reporter assays that the long noncoding RNA LINC02747 was targeted and regulated by METTL14 via m6A modification, and inhibiting LINC02747 was observed to hinder the malignant progression of NSCLC by modulating the PI3K/Akt signaling pathway. Knockdown of METTL14 significantly decreased the m6A modification of LINC02747 and upregulated its expression. Further studies revealed that overexpression of METTL14 promoted m6A methylation and accelerated the decay of LINC02747 mRNA via increased recognition of the "GAACU" binding site by YTHDC2. Additionally, histone demethylase lysine-specific histone demethylase 5B (KDM5B) mediated the demethylation of histone H3 lysine 4 tri-methylation (H3K4me3) in the METTL14 promoter region and repressed its transcription, and KDM5B upregulated the expression of LINC02747 by suppressing the expression of METTL14. Conclusions In summary, KDM5B downregulated METTL14 expression at the transcriptional level in a H3K4me3-dependent manner, while METTL14 modulated LINC02747 expression via m6A modification. Our results demonstrate a series of mechanisms that regulate the malignant phenotype of NSCLC cells, revealing the complex regulation involved in the occurrence and development of cancer.