Emerging role of m6A methylation modification in ovarian cancer

Synchronous profiling of mRNA N6-methyladenosine modifications and mRNA expression in high-grade serous ovarian cancer: a pilot study

This study aimed to synchronously determine epitranscriptome-wide RNA N6-methyladenosine (m6A) modifications and mRNA expression profile in high grade serous ovarian cancer (HGSOC). The methylated RNA immunoprecipitation sequencing (MeRIP-seq) was used to comprehensively examine the m6A modification profile and the RNA-sequencing (RNA-seq) was performed to analyze the mRNA expression profile in HGSOC and normal fallopian tube (FT) tissues. Go and KEGG analyses were carried out in the enrichment of those differentially methylated and expressed genes. MeRIP-seq data showed 53,794 m6A methylated peaks related to 19,938 genes in the HGSOC group and 51,818 m6A peaks representing 19,681 genes in the FT group. RNA-seq results revealed 2321 upregulated and 2486 downregulated genes in HGSOC. Conjoint analysis of MeRIP-seq and RNA-seq data identified differentially expressed genes in which 659 were hypermethylated (330 up- and 329 down-regulated) and 897 were hypomethylated (475 up- and 422 down-regulated). Functional enrichment analysis indicated that these differentially modulated genes are involved in pathways related to cancer development. Among methylation regulators, the m6A eraser (FTO) expression was significantly lower, but the m6A readers (IGF2BP2 and IGF2BP3) were higher in HGSOC, which was validated by the subsequent real-time PCR assay. Exploration through public databases further corroborated their possible clinical application of certain methylation regulators and differentially expressed genes. For the first time, our study screens the epitranscriptome-wide m6A modification and expression profiles of their modulated genes and signaling pathways in HGSOC. Our findings provide an alternative direction in exploring the molecular mechanisms of ovarian pathogenesis and potential biomarkers in the diagnosis and predicting the prognosis of the disease.

m6A-modified circASXL1 promotes proliferation and migration of ovarian cancer through the miR-320d/RACGAP1 axis

Ovarian cancer (OC) is one of the most common malignant tumors in women. Circular RNAs (circRNAs) can potentially regulate the development of OC. Therefore, this study investigated the role of circASXL1 in OC progression. Cell functions were assessed by MTT, colony formation, wound healing, and transwell assays. RIP and dual luciferase reporter assays confirmed the relationship between miR-320d and circASXL1 or RACGAP1. MeRIP was utilized to detect m6A levels. Xenograft tumor was established for in vivo experiments. CircASXL1 and RACGAP1 levels were increased in OC tissues and cells, whereas miR-320d expression was decreased. Upregulation of circASXL1 was associated with poor prognosis in OC patients. CircASXL1 silencing suppressed OC cell proliferation, migration and invasion in vitro and in vivo. Mechanistically, METTL3/IGF2BP1-mediated m6A modification maintained circASXL1 stability and upregulated its expression. CircASXL1 was a ceRNA that sequestrated miR-320d from RACGAP1, leading to increased RACGAP1 expression. CircASXL1 promoted OC cell proliferation, migration and invasion via the miR-320d/RACGAP1 axis. Therefore, m6A-modified circASXL1 acts as an oncogene in OC by targeting miR-320d and activating RACGAP1/PI3K/Akt pathway, which provides novel promising biomarkers for OC diagnosis.

Identification of the expression patterns and potential prognostic role of m6A-RNA methylation regulators in Wilms Tumor

BACKGROUND

To explore the potential role of m6A methylation modification in Wilms Tumor (WT) by m6A-RNA Methylation (m6A) regulators.

METHODOLOGY

The association of m6A modification patterns with immune and prognostic characteristics of tumors was systematically evaluated using 19 m6A regulators extracted from Wilms Tumor's samples in public databases. A comprehensive model of "m6Ascore" was constructed using principal component analysis, and its prognostic value was evaluated.

RESULTS

Almost all m6A regulators were differentially expressed between WT and normal tissues. Unsupervised clustering identified three distinct m6A clusters that differed in both immune cell infiltration and biological pathways. The m6Ascore was constructed to quantify m6A modifications in individual patients. Our analysis suggests that m6Ascore is an independent prognostic factor for WT and can be used as a novel predictor of WT prognosis.

CONCLUSIONS

This study comprehensively explored and systematically characterized m6A modifications in WT. m6A modification patterns play a critical role in the tumor immune microenvironment (TIME) and WT prognosis. m6Ascore provides a more comprehensive understanding of m6A modifications in WT and offers a practical tool for predicting WT prognosis. This study will help clinicians to identify valid indicators of WT to improve the poor prognosis of this disease.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at https://www.aliyundrive.com/drive/folder/64be739cd6956a741fb24670baeea53422be6024 .

RNA epigenetic modifications in ovarian cancer: The changes, chances, and challenges

Ovarian cancer (OC) is the most common female cancer worldwide. Patients with OC have high mortality because of its complex and poorly understood pathogenesis. RNA epigenetic modifications, such as m6 A, m1 A, and m5 C, are closely associated with the occurrence and development of OC. RNA modifications can affect the stability of mRNA transcripts, nuclear export of RNAs, translation efficiency, and decoding accuracy. However, there are few overviews that summarize the link between m6 A RNA modification and OC. Here, we discuss the molecular and cellular functions of different RNA modifications and how their regulation contributes to the pathogenesis of OC. By improving our understanding of the role of RNA modifications in the etiology of OC, we provide new perspectives for their use in OC diagnosis and treatment. This article is categorized under: RNA Processing > RNA Editing and Modification RNA in Disease and Development > RNA in Disease.

Low expression of m6A reader YTHDC1 promotes progression of ovarian cancer via PIK3R1/STAT3/GANAB axis

Background: N6-Methyladenosine (m6A) is considered to be the most prevalent and abundant internal modification observed in mRNA between viruses and mammals. As a reversible epigenetic modification, m6A controls gene expression in diverse physiological and pathological processes. Accumulating evidence in recent years reveals that aberrant expression of m6A reader proteins may have tumor-suppressing or carcinogenic functions. However, the biological role and mechanism of m6A reader YTH Domain Containing 1 (YTHDC1) in ovarian cancer progression remain inadequately understood. Methods: Quantitative RT-PCR, immunohistochemistry, Western blot, and bioinformatics analyses were undertaken for studying the YTHDC1 expression in ovarian cancer. In vitro and in vivo models were used to examine the role of YTHDC1. RNA sequencing, RNA immunoprecipitation sequencing, m6A-modified RNA immunoprecipitation, actinomycin-D assay, chromatin immunoprecipitation, and Western blot were used in the investigation the regulatory mechanisms among YTHDC1, Signal Transducer and Activator of Transcription 3 (STAT3), Phosphoinositide-3-Kinase Regulatory Subunit 1 (PIK3R1), and Glucosidase II Alpha Subunit (GANAB). Results: Here, we found that YTHDC1 expression is decreased in ovarian cancer. Overexpression of YTHDC1 inhibited ovarian cancer development both in vivo and in vitro. Mechanistically, PIK3R1 was identified to be the direct target for YTHDC1. YTHDC1 enhanced PIK3R1 stability in an m6A-dependent manner, which subsequently inhibited GANAB expression in the N-glycan biosynthesis via the STAT3 signaling. Conclusions: Our findings unveil YTHDC1 as a tumor suppressor in the progression of ovarian cancer and as a potential prognostic biomarker that could serve as a target in ovarian cancer treatment.

The role of RNA methyltransferase METTL3 in gynecologic cancers: Results and mechanisms

N6-methyladenosine (m6A) methylation is the most prevalent mRNA modification in eukaryotes, and it is defined as the methylation of nitrogen atoms on the six adenine (A) bases of RNA in the presence of methyltransferases. Methyltransferase-like 3 (Mettl3), one of the components of m6A methyltransferase, plays a decisive catalytic role in m6A methylation. Recent studies have confirmed that m6A is associated with a wide spectrum of biological processes and it significantly affects disease progression and prognosis of patients with gynecologic tumors, in which the role of Mettl3 cannot be ignored. Mettl3 is involved in numerous pathophysiological functions, such as embryonic development, fat accumulation, and tumor progression. Moreover, Mettl3 may serve as a potential target for treating gynecologic malignancies, thus, it may benefit the patients and prolong survival. However, there is a need to further study the role and mechanism of Mettl3 in gynecologic malignancies. This paper reviews the recent progression on Mettl3 in gynecologic malignancies, hoping to provide a reference for further research.

N6-methyladenosine methylation regulator FTO promotes oxidative stress and induces cell apoptosis in ovarian cancer

Aims: This study aimed to reveal the possible molecular mechanism of n6-methyladenosine (m6A) methylation regulator FTO in the biological activities of ovarian cancer (OC) based on The Cancer Genome Atlas, Genotype-Tissue Expression and Gene Expression Omnibus databases. Materials & methods: A risk score model was constructed to predict the prognosis of patients with OC. The key m6A methylation regulator was screened out based on OC-related microarray datasets. Results: 22 m6A methylation regulators were differentially expressed and interacted with each other in OC. FTO, a key m6A methylation regulator, was singled out. In vivo experiments verified that FTO promoted oxidative stress and apoptosis of OC cells to inhibit tumor growth in nude mice. Conclusion: This study highlighted the tumor-suppressive mechanism of m6A methylation regulator FTO in OC.

Identification of key genes associated with polycystic ovary syndrome (PCOS) and ovarian cancer using an integrated bioinformatics analysis

BACKGROUND

Accumulating evidence suggests a strong association between polycystic ovary syndrome (PCOS) and ovarian cancer (OC), but the potential molecular mechanism remains unclear. In this study, we identified previously unrecognized genes that are significantly correlated with PCOS and OC via bioinformatics.

MATERIALS AND METHODS

Multiple bioinformatic analyses, such as differential expression analysis, univariate Cox analysis, functional and pathway enrichment analysis, protein-protein interaction (PPI) network construction, survival analysis, and immune infiltration analysis, were utilized. We further evaluated the effect of OGN on FSHR expression via immunofluorescence.

RESULTS

TCGA-OC, GSE140082 (for OC) and GSE34526 (for PCOS) datasets were downloaded. Twelve genes, including RNF144B, LPAR3, CRISPLD2, JCHAIN, OR7E14P, IL27RA, PTPRD, STAT1, NR4A1, OGN, GALNT6 and CXCL11, were identified as signature genes. Drug sensitivity analysis showed that OGN might represent a hub gene in the progression of PCOS and OC. Experimental analysis found that OGN could increase FSHR expression, indicating that OGN could regulate the hormonal response in PCOS and OC. Furthermore, correlation analysis indicated that OGN function might be closely related to m6A and ferroptosis.

CONCLUSIONS

Our study identified a 12-gene signature that might be involved in the prognostic significance of OC. Furthermore, the hub gene OGN represent a significant gene involved in OC and PCOS progression by regulating the hormonal response.