RNA demethylase ALKBH5 prevents pancreatic cancer progression by posttranscriptional activation of PER1 in an m6A-YTHDF2-dependent manner

Yun Feng,Xingya Guo,Qin Pan,Kai Li,Yangyang Hu,Weiliang Jiang,Rong Wan,Wenqin Xiao,Yinshi Huang

doi:10.1186/s12943-020-01158-w

Yun Feng, Xingya Guo + Show 7 more

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https://doi.org/10.1186/s12943-020-01158-w

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Journal: Molecular Cancer	Publication Date: May 19, 2020
Citations: 240	License type: open-access

Affiliation: Shanghai First People's Hospital, XinHua Hospital

Abstract

BackgroundN6-methyladenosine (m6A) is the most abundant reversible methylation modification of eukaryotic mRNA, and it plays vital roles in tumourigenesis. This study aimed to explore the role of the m6A demethylase ALKBH5 in pancreatic cancer (PC).MethodsThe expression of ALKBH5 and its clinicopathological impact were evaluated in PC cohorts. The effects of ALKBH5 on the biological characteristics of PC cells were investigated on the basis of gain-of-function and loss-of-function analyses. Subcutaneous and orthotopic models further uncovered the role of ALKBH5 in tumour growth. mRNA and m6A sequencing and assays of m6A methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) were performed to identify the targeted effect of ALKBH5 on PER1. P53-binding sites in the ALKBH5 promoter were investigated by ChIP and luciferase assays to reveal the interplay between ALKBH5 and PER1-activated ATM-CHK2-P53/CDC25C signalling.ResultsALKBH5 loss characterized the occurrence and poor clinicopathological manifestations in patients with PC. Overexpression of ALKBH5 reduced tumoural proliferative, migrative, invasive activities in vitro and ameliorated tumour growth in vivo, whereas ALKBH5 knockdown facilitated PC progression. Mechanistically, ALKBH5 posttranscriptionally activated PER1 by m6A demethylation in an m6A-YTHDF2-dependent manner. PER1 upregulation led to the reactivation of ATM-CHK2-P53/CDC25C signalling, which inhibited cell growth. P53-induced activation of ALKBH5 transcription acted as a feedback loop regulating the m6A modifications in PC.ConclusionALKBH5 serves as a PC suppressor by regulating the posttranscriptional activation of PER1 through m6A abolishment, which may highlight a demethylation-based approach for PC diagnosis and therapy.

Highlights

N6-methyladenosine (m6A) is the most abundant reversible methylation modification of eukaryotic mRNA, and it plays vital roles in tumourigenesis
N6-methyladenosine (m6A), first reported in the 1970s [5, 6], is the most prevalent modification of the epitranscriptome in eukaryotic cells [7]. m6A modifications reflect a dynamic and reversible process [8, 9] that is introduced by the m6A methyltransferase complex (MTC) composing methyltransferase-like 3 (METTL3), METTL14 and Wilms tumour 1-associated protein (WTAP), and is demethylated by human AlkB homolog H5 (ALKBH5) and fat mass and obesity-associated protein (FTO) [8,9,10,11,12]
Real-time qPCR showed a significant reduction in ALKBH5 mRNA levels in pancreatic cancer (PC) tissues compared to noncancerous controls (Fig. 1a)

Summary

Introduction

N6-methyladenosine (m6A) is the most abundant reversible methylation modification of eukaryotic mRNA, and it plays vital roles in tumourigenesis. This study aimed to explore the role of the m6A demethylase ALKBH5 in pancreatic cancer (PC). Accumulating proofs confirm that the m6A modification regulates multiple biological functions, such as RNA processing, nuclear export, translation, degradation and RNA-protein interactions [9, 13,14,15], whereas aberrant m6A modification underlies embryonic development disorders, tumourigenesis, failures in homeostasis and differentiation of immune cells, and nervous system diseases [16,17,18,19]. M6A modification functions in condition of its recognition by m6A reader proteins (YT521-B homology (YTH) domain family [15], heterogeneous nuclear ribonucleoprotein (hnRNP)) [23]

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