M6A mRNA methylation regulates CTNNB1 to promote the proliferation of hepatoblastoma

Li Liu,Xin Zhang,Guifeng Sun,Min Xu,Minzhi Yin,Jing Wang,Qiuhui Pan,Qiong Wu,Nan Huang,Fenyong Sun,Song Gu,Zhixuan Bian,Ji Ma

doi:10.1186/s12943-019-1119-7

Abstract

BackgroundN6-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).MethodsWe 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.ResultsIn 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.ConclusionOverall 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.

Highlights

Hepatoblastoma (HB) is the most common pediatric liver cancer
The abnormal m6A modification in HB and the functional roles of methyltransferase-like 13 (METTL3), Wilms’ tumor 1-associating protein (WTAP), fat mass and obesity-associated protein (FTO), YTHDF2 in HB cells To explore the potential role of m6A modification in HB, we first examined m6A levels in the tumor and normal tissues
We evaluated the expression of m6A writers, erasers and readers in tumor and adjacent normal hepatic tissues by quantitative PCR coupled with reverse transcription (RT-qPCR) and Western blotting

Summary

Introduction

Hepatoblastoma (HB) is the most common pediatric liver cancer. It is an embryonal neoplasms and mostly can be diagnosed during the first three years of life. It originates from undifferentiated hepatic progenitor cells, and undergo a malignant transformation during embryogenesis [1, 2]. Typical therapeutic strategies such as combined surgery and chemotherapy have demonstrated improved outcomes for children with HB. N6-Methyladenosine (m6A) modification has been implicated in many biological processes. We investigated the biological role and underlying mechanism of m6A modification in hepatoblastoma (HB)

Methods

Results

Discussion

Conclusion