m6A-dependent glycolysis enhances colorectal cancer progression

Abstract

Background: Epigenetic alterations are involved in various aspects of colorectal carcinogenesis. N 6methyladenosine (m 6 A) modifications of RNAs are emerging as a new layer of epigenetic regulation. As the most abundant chemical modification of eukaryotic mRNA, m 6 A is essential for the regulation of mRNA stability, splicing, and translation. Alterations of m 6 A regulatory genes play important roles in the pathogenesis of a variety of human diseases. However, whether this mRNA modification participates in the glucose metabolism of colorectal cancer (CRC) remains uncharacterized. Methods: Transcriptome-sequencing and liquid chromatography-tandem mass spectrometry (LC-MS) were performed to evaluate the correlation between m 6 A modifications and glucose metabolism in CRC. Mass spectrometric metabolomics analysis, in vitro and in vivo experiments were conducted to investigate the effects of METTL3 on CRC glycolysis and tumorigenesis. RNA MeRIP-sequencing, immunoprecipitation and RNA stability assay were used to explore the molecular mechanism of METTL3 in CRC. Results: A strong correlation between METTL3 and 18 F-FDG uptake was observed in CRC patients from Xuzhou Central Hospital. METTL3 induced-CRC tumorigenesis depends on cell glycolysis in multiple CRC models. Mechanistically, METTL3 directly interacted with the 5′/3'UTR regions of HK2, and the 3'UTR region of SLC2A1 (GLUT1), then further stabilized these two genes and activated the glycolysis pathway. M 6 A-mediated HK2 and SLC2A1 (GLUT1) stabilization relied on the m 6 A reader IGF2BP2 or IGF2BP2/3, respectively. Conclusions: METTL3 is a functional and clinical oncogene in CRC. METTL3 stabilizes HK2 and SLC2A1 (GLUT1) expression in CRC through an m 6 A-IGF2BP2/3-dependent mechanism. Targeting METTL3 and its pathway offer alternative rational therapeutic targets in CRC patients with high glucose metabolism.

Roles of METTL3 in cancer: mechanisms and therapeutic targeting

“…The accumulating studies in recent years have revealed diverse pathways in cancers that are affected by METTL3, mostly focused on cell proliferation, cell death resistance, invasion, and metastasis (Table 2). However, emerging evidence also suggests that METTL3 plays vital roles in other biological processes, such as angiogenesis [58] and metabolism dysregulation [58,101]. A recent publication showed that m 6 A modification of viral RNA enables the virus to avoid detection by innate immunity [143]; thus, there is a possibility that METTL3 might also mediate immune escape in cancers.…”

Peer Review #1 of "Prognostic model of invasive ductal carcinoma of the breast based on differentially expressed glycolysis-related genes (v0.1)"

“…There is evidence that changes in glycolysis-related genes have multiple effects on the prognosis of these patients Chen et al, 2019). In particular, tumor cells reprogram the glycolysis pathway to accommodate the increased energy required for malignant transformations, including invasion and metastasis (Shen et al, 2020;Abbaszadeh et al, 2020).…”

“…Research on the function of glycolysis-related genes in breast tumors showed that hexokinase (HK2) had high expression in breast IDC cells, and that HK2 silencing inhibited IDC (Patra et al, 2013;Cao et al, 2020). Other research showed that overexpression of 6-Phosphofructo 2-kinase/fructose 2, 6-bisphosphatase 3 (PFKFB3) promoted the progression of breast IDC, and had negative associations with progression-free survival (PFS), distant metastasis-free survival (DMFS), and overall survival (OS) in patients with breast IDC (O'Neal et al, 2016;Peng et al, 2018).…”

Advances in the role of m6A RNA modification in cancer metabolic reprogramming

“…As we described above, the "writers", "erasers" or "readers" induce m 6 Glucose metabolism HK2, GLUT1 m 6 A modification was closely correlated with glycolysis pathway activation in colorectal cancer patients' tissues. Mechanically, HK2, and GLUT1 were found to be regulated by m 6 A modification and participate in glycolysis activation in colorectal cancer [17] PKM2 FTO triggered the m 6 A demethylation of PKM2 mRNA and accelerated the translated production, thus promoting hepatocellular carcinoma tumorigenesis [96] PIK3CB A missense variant rs142933486 in PIK3CB reduced the PIK3CB m 6 A level and facilitated its mRNA and protein expression levels mediated by the m 6 A "writers" complex (METTL3/METTL14/WTAP) and YTHDF2 [97] EGFR, MEK/ERK signaling YTHDF2 negatively modulated the EGFR mRNA stability in HCC via its binding the m 6 A site in the EGFR 3′-UTR, which in turn impaired the MEK/ERK pathway and consequently impedes the cell proliferation and growth [102] NF-κB signaling METTL3 positively regulated MYD88 expression through controlling m 6 A methylation status of MYD88-RNA, leading to the activation of NF-κB signaling [103] NF-κB signaling METTL3 activated NF-κB signaling by promoting the expression of IKBKB and RELA through regulating translational efficiency [94] AKT signaling m 6 A methylation normally attenuates AKT activity in the endometrium by promoting the m 6 Adependent translation of PHLPP2 and m 6 A-dependent degradation of transcripts encoding subunits of mTORC2, increasing proliferation and tumorigenicity in endometrial cancer [14] AKT signaling The association between m 6 A and AKT signaling was also confirmed in multiple tumor types including leukemia cells and clear cell renal cell carcinoma [101,117] Lipid metabolism ACC1, ACLY, DGAT2, EHHADH, FASN, FOXO, PGC1A, and SIRT1 ACC1, ACLY, DGAT2, EHHADH, FASN, FOXO, PGC1A, and SIRT1 were dramatically decreased in livers of hepatocyte-specific METTL3 knockout mice. CD36 and LDLR were also downregulated by improving the expression of FASN through its m 6 A demethylase activity [106] SREBP1c, CIDEC FTO increased lipid accumulation by a novel FTO/SREBP1c/CIDEC signaling pathway in an m 6 A-dependent manner in HepG2 cells [108] SREBP1c, FASN, SCD1, ACC1 YTHDF2 could also bind to the mRNA of SREBP1c, FASN, SCD1, and ACC1, to decrease their mRNA stability and inhibit gene expression [109] AMPK m 6 A modification resulted in reduced AMPK activity…”