m6A mRNA methylation regulates CTNNB1 to promote the proliferation of hepatoblastoma

Abstract

Background

N⁶-Methyladenosine (m⁶A) modification has been implicated in many biological processes. It is important for the regulation of messenger RNA (mRNA) stability, splicing, and translation. However, its role in cancer has not been studied in detail. Here we investigated the biological role and underlying mechanism of m⁶A modification in hepatoblastoma (HB).

Methods

We used Reverse transcription quantitative real-time PCR (RT-qPCR) and Western blotting to determine the expression of m⁶A related factors. And we clarified the effects of these factors on HB cells using cell proliferation assay, colony formation, apoptotic assay. Then we investigated of methyltransferase-like 13 (METTL3) and its correlation with clinicopathological features and used xenograft experiment to check METTL3 effect in vivo. m⁶A-Seq was used to profiled m⁶A transcriptome-wide in hepatoblastoma tumor tissue and normal tissue. Finally, methylated RNA immunoprecipitation (MeRIP) assay, RNA remaining assay to perform the regulator mechanism of MEETL3 on the target CTNNB1 in HB.

Results

In this research, we discovered that m⁶A modifications are increased in hepatoblastoma, and METTL3 is the main factor involved with aberrant m⁶A modification. We also profiled m⁶A across the whole transcriptome in hepatoblastoma tumor tissues and normal tissues. Our findings suggest that m⁶A is highly expressed in hepatoblastoma tumors. Also, m⁶A is enriched not only around the stop codon, but also around the coding sequence (CDS) region. Gene ontology analysis indicates that m⁶A mRNA methylation contributes significantly to regulate the Wnt/β-catenin pathway. Reduced m⁶A methylation can lead to a decrease in expression and stability of the CTNNB1.

Conclusion

Overall our findings suggest enhanced m⁶A mRNA methylation as an oncogenic mechanism in hepatoblastoma, METTL3 is significantly up-regulated in HB and promotes HB development. And identify CTNNB1 as a regulator of METTL3 guided m⁶A modification in HB.