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METTL3 promotes tumour development by decreasing APC expression mediated by APC mRNA N⁶-methyladenosine-dependent YTHDF binding.

ABSTRACT: The adenomatous polyposis coli (APC) is a frequently mutated tumour suppressor gene in cancers. However, whether APC is regulated at the epitranscriptomic level remains elusive. In this study, we analysed TCGA data and separated 200 paired oesophageal squamous cell carcinoma (ESCC) specimens and their adjacent normal tissues and demonstrated that methyltransferase-like 3 (METTL3) is highly expressed in tumour tissues. m⁶A-RNA immunoprecipitation sequencing revealed that METTL3 upregulates the m⁶A modification of APC, which recruits YTHDF for APC mRNA degradation. Reduced APC expression increases the expression of β-catenin and β-catenin-mediated cyclin D1, c-Myc, and PKM2 expression, thereby leading to enhanced aerobic glycolysis, ESCC cell proliferation, and tumour formation in mice. In addition, downregulated APC expression correlates with upregulated METTL3 expression in human ESCC specimens and poor prognosis in ESCC patients. Our findings reveal a mechanism by which the Wnt/β-catenin pathway is upregulated in ESCC via METTL3/YTHDF-coupled epitranscriptomal downregulation of APC.

SUBMITTER: Wang W

PROVIDER: S-EPMC8217513 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundN6-Methyladenosine (m6A) methylation is the most prevalent internal posttranscriptional modification on mammalian mRNA. The role of m6A mRNA methylation in the heart is not known.MethodsTo determine the role of m6A methylation in the heart, we isolated primary cardiomyocytes and performed m6A immunoprecipitation followed by RNA sequencing. We then generated genetic tools to modulate m6A levels in cardiomyocytes by manipulating the levels of the m6A RNA methylase methyltransferase-like 3 (METTL3) both in culture and in vivo. We generated cardiac-restricted gain- and loss-of-function mouse models to allow assessment of the METTL3-m6A pathway in cardiac homeostasis and function.ResultsWe measured the level of m6A methylation on cardiomyocyte mRNA, and found a significant increase in response to hypertrophic stimulation, suggesting a potential role for m6A methylation in the development of cardiomyocyte hypertrophy. Analysis of m6A methylation showed significant enrichment in genes that regulate kinases and intracellular signaling pathways. Inhibition of METTL3 completely abrogated the ability of cardiomyocytes to undergo hypertrophy when stimulated to grow, whereas increased expression of the m6A RNA methylase METTL3 was sufficient to promote cardiomyocyte hypertrophy both in vitro and in vivo. Finally, cardiac-specific METTL3 knockout mice exhibit morphological and functional signs of heart failure with aging and stress, showing the necessity of RNA methylation for the maintenance of cardiac homeostasis.ConclusionsOur study identified METTL3-mediated methylation of mRNA on N6-adenosines as a dynamic modification that is enhanced in response to hypertrophic stimuli and is necessary for a normal hypertrophic response in cardiomyocytes. Enhanced m6A RNA methylation results in compensated cardiac hypertrophy, whereas diminished m6A drives eccentric cardiomyocyte remodeling and dysfunction, highlighting the critical importance of this novel stress-response mechanism in the heart for maintaining normal cardiac function.

Project description:BackgroundChemotherapy is an important strategy for the treatment of hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+HER2-) breast cancer (BC), but this subtype has a low response rate to chemotherapy. Growing evidence indicates that N6-methyladenosine (m6A) is the most common RNA modification in eukaryotic cells and that methyltransferase-like 3 (METTL3) participates in tumour progression in several cancer types. Therefore, exploring the function of METTL3 in HR+HER2- BC initiation and development is still important.MethodsmRNA and protein expression levels were analysed by quantitative real-time polymerase chain reaction and western blotting, respectively. Cell proliferation was detected by CCK-8 and colony formation assays. Cell cycle progression was assessed by flow cytometry. Cell migration and invasion were analysed by wound healing assays and transwell assays, respectively, and apoptosis was analysed by TUNEL assays. Finally, m6A modification was analysed by methylated RNA immunoprecipitation.ResultsChemotherapy-induced downregulation of the m6A modification is regulated by METTL3 depletion in HR+HER2- BC. METTL3 knockdown in MCF-7/T47D cells decreased the drug sensitivity of HR+HER2- BC cells by promoting tumour proliferation and migration and inhibiting apoptosis. Mechanistically, CDKN1A is a downstream target of METTL3 that activates the AKT pathway and promotes epithelial-mesenchymal transformation (EMT). Moreover, a decrease in BAX expression was observed when m6A modification was inhibited with METTL3 knockdown, and apoptosis was inhibited by the reduction of caspase-3/-9/-8.ConclusionMETTL3 depletion promotes the proliferation and migration and decreases the drug sensitivity of HR+HER2- BC via regulation of the CDKN1A/EMT and m6A-BAX/caspase-9/-3/-8 signalling pathways, which suggests METTL3 played a tumour-suppressor role and it could be a potential biomarker for predicting the prognosis of patients with HR+HER2- BC.

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METTL3 promotes tumour development by decreasing APC expression mediated by APC mRNA N⁶-methyladenosine-dependent YTHDF binding.

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Dataset Information

METTL3 promotes tumour development by decreasing APC expression mediated by APC mRNA N6-methyladenosine-dependent YTHDF binding.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

METTL3 promotes tumour development by decreasing APC expression mediated by APC mRNA N⁶-methyladenosine-dependent YTHDF binding.