N-Methyladenosine-Modified LEAWBIH Drives Hepatocellular Carcinoma Progression through Epigenetically Activating Wnt/β-Catenin Signaling.

PURPOSE

N-methyladenosine (mA) modification plays an important role in regulating RNA maturation, stability, and translation. Thus, mA modification is involved in various pathophysiological processes including hepatocellular carcinoma (HCC). However, the direct contribution of mA modifications to RNA function in HCC remains unclear. Here, we identified LEAWBIH (long non-coding RNA epigenetically activating Wnt/β-catenin signalling in HCC) as an mA-modified long non-coding RNA (lncRNA) and investigated the effects of mA on the function of LEAWBIH in HCC.

METHODS

Quantitative polymerase chain reaction was performed to measure the gene expression in tissues and cells. The level of mA modification was detected using a methylated RNA immunoprecipitation assay and single-base elongation- and ligation-based qPCR amplification method. Cell proliferation was evaluated using the Glo cell viability and CCK-8 assays. Cell migration and invasion were evaluated using Transwell migration and invasion assays. The mechanisms of mA modified LEAWBIH were investigated using chromatin isolation by RNA purification, chromatin immunoprecipitation, and dual-luciferase reporter assays.

RESULTS

LEAWBIH was highly expressed and correlated with poor survival in HCC patients. LEAWBIH was identified as a mA-modified transcript. mA modification increased LEAWBIH transcript stability. The mA modification level of LEAWBIH was increased in HCC, and a high mA modification level of LEAWBIH predicted poor survival. LEAWBIH promotes HCC cell proliferation, migration, and invasion in an mA modification-dependent manner. Mechanistic investigations revealed that mA-modified LEAWBIH activated Wnt/β-catenin signaling. mA-modified LEAWBIH binds to the mA reader YTHDC1, which further interacts with and recruits H3K9me2 demethylase KDM3B to promoter, leading to H3K9me2 demethylation and transcription activation. Functional rescue assays showed that blocking Wnt/β-catenin signaling abolished the role of LEAWBIH in HCC.

CONCLUSION

mA-modified LEAWBIH exerts oncogenic effects in HCC by epigenetically activating Wnt/β-catenin signaling, highlighting mA-modified LEAWBIH as a promising therapeutic target for HCC.