RNA-seq of human breast cancer cell line MDA-MB-231 treated with STM2457 against untreated controls
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ABSTRACT: Here, we aim to investigate if catalytic inhibition of the m6A methyltransferase METTL3 by the small-molecule STM2457 may be a viable treatment option for TNBC.
Project description:To gain insight into possible processes that require m6A for their function, METTL3 was knocked down (KD) in HepG2 cells by siRNA transfections Differential expression analysis of METTL3 KD versus mock-transfected HepG2 cells, in 2 biological replicates
Project description:METTL3-mediated RNA N6-methyladenosine (m6A) is the most prevalent modification participates in tumor initiation and progression via regulating expression of their target genes in cancers. However, its role in tumor cell metabolism remains poorly appreciated. In this study, we conducted a multi-omics analysis including m6A microarray and quantitative proteomics to explore the potential effect and mechanism of METTL3 on the metabolism in gastric cancer cells. Our results found that significant alterations in the protein and m6A modification profile which induced by METTL3 overexpression in GC cells. Gene Ontology (GO) enrichment results showed that down-regulated proteins were significantly enriched in intracellular mitochondrial oxidative phosphorylation (OXPHOS), and the Protein-Protein Interaction (PPI) network analysis found that these differentially expressed proteins were significantly associated with OXPHOS. Subsequently, a prognostic model constructed based on the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and the high-risk group showed a worse prognosis in GC patients. Meanwhile, the Gene Set Enrichment Analysis (GSEA) showed a significant enrichment in the energy metabolism signaling pathway. Then, combined with the results of the m6A microarray analysis, the intersection molecules of DEPs and differential methylation genes (DMGs) were significantly correlated with the genes involved in OXPHOS. Besides, there were also significant differences in prognosis and GSEA enrichment between the two clusters of GC patients classified according to consensus clustering algorithm. Finally, we focused on highly expressed, highly methylated molecules regulated by METTL3 and identified three (AVEN, DAZAP2, DNAJB1) genes that were significantly associated with poor prognosis in patients with GC. These results indicated that METTL3-regulated DEPs in GC cells were significantly associated with OXPHOS. After combined with m6A microarray analysis, the results suggested that these proteins might be involved in cell energy metabolism through m6A modifications thus influencing the prognosis of GC patients. Overall, our study revealed that METTL3 involved in cell metabolism through an m6A-dependent mechanism in GC cells, and indicated a potential biomarker for prognostic prediction in GC.
Project description:N⁶-methyladenosine (m6A) and its reader, writer, and eraser (RWE) proteins assume crucial roles in regulating the splicing, stability, and translation of mRNA. To our knowledge, no systematic investigations have been conducted about the crosstalk between m6A and other modified nucleosides in RNA. Herein, we modified our recently established liquid chromatography-parallel-reaction monitoring (LC-PRM) method by incorporating stable isotope-labeled (SIL) peptides as internal or surrogate standards for profiling epitranscriptomic RWE proteins. We were able to detect reproducibly a total of 114 RWE proteins in HEK293T cells with the genes encoding m6A eraser proteins (i.e., ALKBH5, FTO) and the catalytic subunit of the major m6A writer complex (i.e., METTL3) being individually ablated. Notably, eight proteins were altered by more than 1.5-fold in the opposite directions in HEK293T cells depleted of METTL3 and ALKBH5. Analysis of published m6A mapping results revealed the presence of m6A in the corresponding mRNAs of four of these proteins. Together, we integrated SIL peptides into our LC-PRM method for quantifying epitranscriptomic RWE proteins, and our work revealed potential crosstalks between m6A and other epitranscriptomic modifications. Our modified LC-PRM method with the use of SIL peptides should be applicable for high-throughput profiling of epitranscriptomic RWE proteins in other cell types and in tissues.
Project description:N6-methyladenosine (m6A) is the most prevalent internal modification found in mammalian messenger and non-coding RNAs. The discoveries of functionally significant demethylases that reverse this methylation as well as the recently revealed m6A distributions in mammalian transcriptomes strongly indicate regulatory functions of this modification. Here we report the identification and characterization of the mammalian nuclear RNA N6-adenosine methyltransferase core (RNMTC) complex. Besides METTL3, a methyltransferase which was the only known component of RNMTC in the past, we discovered that a previously uncharacterized methyltransferase, METTL14, exhibits a N6-adenosine methyltransferase activity higher than METTL3. Together with WTAP, the third component that dramatically affects the cellular m6A level, these three proteins form the core complex that orchestrates m6A deposition on mammalian nuclear RNA. Biochemistry assays, imaging experiments, as well as transcriptome-wide analyses of the binding sites and their effects on m6A methylation support methylation function and reveal new insights of RNMTC. PAR-CLIP and m6A-seq in HeLa cells
Project description:We report the application of MeRIP sequencing technology for high-throughput profiling of m6A methylome in breast cancer cells. Comparison of m6A methylome between METTL3-WT and METTL3-K177Q reconstituting cells revealed the following findings: 1) Significant global alteration of methylation sites due to K177Q mutation (termed as KQ-m6A signature). 2) GO analysis of the differential m6A-MeRIP candidates enriched pathways involved in chromatin modification, RNA splicing, DNA damage, cell cycle, and autophagy, consistent with a critical role of m6A-mediated nuclear biological activities and highlighted generally recognized cellular events associated with tumorigenesis. 3) we dissected potential mechanistic clues explaining the attenuated invasive phenotype in METTL3K177Q reconstituting cells.
Project description:Previous studies have shown that nuclear localization of METTL3 is associated with CDDP resistance. To identify key PTMS involved in the nuclear localization of METTL3 in CDDP-resistant ovarian cancer cells, we assessed the global methylation of arginine, as well as METTL3 phosphorylation, acetylation, O-GlcNAcylation, and crotonylation in CDDP-resistant and parental ovarian cancer cells. The results showed that arginine methylation of METTL3 was increased in CDDP-resistant cell lines. To further identify the arginine methylation sites that may be involved in the METTL3 resistance mechanism, we identified the methylation modification sites of METTL3 by mass spectrometry.
Project description:Recent methylome studies have located N6-methyladenosine (m6A) RNA modification on thousands of mammalian transcripts. However, its functional mechanism remains unclear. In this study, we examined the role of m6A methylation in mouse embryonic stem cells. To gain an understanding of dynamic changes in cells depleted with (proposed) methyltranferases at molecular level, we examined the time-series gene expression pattern in mESC lines using microarray analysis. After 0, 4 and 8 h incubation with scramble, shRNA for Mettl3 or Mettl14, mESC cells were collected and RNAs were isolated for microarray analysis using Affymetrix Genechip Mouse Gene 2.0 ST array. After 0 h incubation with scramble, shRNA for Mettl3 or Mettl14, mESC cells were collected and RNAs were isolated for microarray analysis using Affymetrix Genechip Mouse Gene 2.0 ST array.
Project description:This SuperSeries is composed of the following subset Series: GSE36958: Gene expression profiles of WT and ime4-/- mutant yeast cells, under vegetative and meiosis-inducing conditions GSE37001: METTL3 KD in HepG2 cells GSE37002: m6A mapping in human RNA (with treatments) GSE37003: m6A mapping in human RNA (untreated) GSE37004: m6A mapping in mouse RNA (mouse liver and human brain) Refer to individual Series
Project description:Aberrant expression of m6A writer complex has been reported across human cancers, resulting in abnormal m6A epitranscriptome that drives tumorigenesis. But the regulatory mechanism remains unknown. Here, we identified an unappreciated interplay between the histone acetyl-lysine reader BRD4 and the m6A methyltransferase complex (MTC) across human cancers. BRD4 directly stimulates transcript expression of seven MTC subunits, allowing the maintenance of nuclear METTL3/METTL14 abundance and the formation of functional writer complex to catalyze m6A modification.