RNA m6A methyltransferase METTL3 regulates invasiveness of melanoma cells by matrix metallopeptidase 2

m6A RNA methylation regulators can contribute to malignant progression and impact the prognosis of bladder cancer

N6-methyladenosine (m6A) is the most common form of messenger RNA (mRNA) modification. An increasing number of studies have proven that m6A RNA methylation regulators are overexpressed in many cancers and participate in the development of cancer through the dynamic regulation of m6A RNA methylation regulators. However, the prognostic role of m6A RNA methylation regulators in bladder cancer (BC) is poorly understood. In the present study, we downloaded the mRNA expression data from The Cancer Genome Atlas (TCGA) database and the corresponding clinical and prognostic information. The relationship between m6A RNA methylation regulators and clinicopathological variables of BC patients was assessed by the Kolmogorov–Smirnov test. The expression of the m6A RNA methylation regulators was differentially associated with different clinicopathological variables of BC patients. The least absolute shrinkage and selection operator (LASSO) Cox regression model was then applied to identify three m6A RNA methylation regulators. The risk signature was constructed as follows: 0.164FTO − (0.081YTHDC1+0.032WTAP). Based on the risk signature, the risk score of each patient was calculated, and the patients were divided into a high-risk group and a low-risk group. The overall survival (OS) rate of the high-risk group was significantly lower than that of the low-risk group. The risk signature was not only an independent prognostic marker for BC patients but also a predictor of clinicopathological variables. In conclusion, m6A RNA methylation regulators can participate in the malignant progression of BC, and a risk signature with three selected m6A RNA methylation regulators may be a promising prognostic biomarker to guide personalized treatment for BC patients.

Upregulation of cervical carcinoma expressed PCNA regulatory long non-coding RNA promotes esophageal squamous cell carcinoma progression

Cervical carcinoma expressed PCNA regulatory long non-coding (lnc)RNA (CCEPR) has recently been reported to play oncogenic roles in some common types of human cancer. However, the clinical significance of CCEPR mRNA expression levels in esophageal squamous cell carcinoma (ESCC) and the exact function of CCEPR in regulating the malignant phenotypes of ESCC cells have not been previously investigated. In the present study, CCEPR mRNA expression level was upregulated in ESCC tissues and cell lines, and overexpression of CCEPR was associated with advanced TNM stage, lymph node metastasis, and poor prognosis in ESCC. In vitro experiments showed that silencing CCEPR mRNA expression levels significantly suppressed the proliferation, migration, and invasion of ESCC cells, while inducing ESCC cell apoptosis. Furthermore, inhibition of CCEPR decreased the protein expression levels of matrix metalloproteinase (MMP)2 and MMP9 and inhibited epithelial-mesenchymal transition in ESCC cells. In conclusion, the results showed that CCEPR plays an oncogenic role in ESCC and suggests that CCEPR could be used as a potential therapeutic target for ESCC treatment.

Multiomics profile and prognostic gene signature of m6A regulators in uterine corpus endometrial carcinoma

Uterine corpus endometrial carcinoma (UCEC) is the most common type of gynecologic malignancy worldwide. Despite advances in the treatments of UCEC, its incidence and mortality rates are still increasing. N6-methyladenosine (m6A) is the most common form of RNA modification and has attracted increasing interest in cancer pathogenesis and progression. Thus, we aimed to identify the landscape of m6A regulators and build a prognostic gene signature in UCEC. In this study, we first analyzed copy number variations (CNVs), single nucleotide variations (SNVs) and gene expression profiles as well as matched clinical information of UCEC patients from The Cancer Genome Atlas (TCGA) database. Next, we determined that CNVs in m6A regulatory genes had a significant negative impact on patient survival. The mRNA expression levels of a total of 16 m6A regulators were significantly correlated with different CNV patterns. Using univariate Cox regression analysis, IGF2BP1, KIAA1429, IGF2BP3, YTHDF3, and IGF2BP2 were found to be closely associated with UCEC patient survival outcomes. Based on the least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression models, we built a 3-gene (IGF2BP3, KIAA1429 and IGF2BP1) signature of m6A regulators with prognostic value in UCEC that could effectively predict patient prognosis (log-rank test p-value < 0.0001). In addition, risk scores were significantly different between patients stratified by tumor stage, SNV, and CNV. Multivariate Cox regression analysis suggested that risk score might be an independent prognostic indicator for the overall survival of patients with UCEC (p-value < 0.05). Gene enrichment analysis indicated that high IGF2BP1 gene expression is associated with cytoplasmic stress granules. KIAA1429 gene expression is associated with cellular nucleic acid metabolism. The expression of the IGF2BP3 gene is associated with RNA binding processes. In conclusion, we determined that genetic alterations in m6A regulatory genes could be effective and reliable biomarkers for UCEC prognosis prediction.

The contribution of WTAP gene variants to Wilms tumor susceptibility

Wilms tumor is the most frequently occurring pediatric renal malignancy. Wilms tumor suppressor-1-associated protein (WTAP) is a vital component of N6-methyltransferase complex involved in tumorigenesis. However, the roles of WTAP gene single nucleotide polymorphisms (SNPs) in Wilms tumor risk have not been clarified to date. We successfully genotyped three WTAP gene SNPs using TaqMan assay in 405 Wilms tumor patients and 1197 cancer-free controls of Chinese children. Odds ratios (ORs) and 95% confidence intervals (CIs) were applied to determine the effects of WTAP gene SNPs on Wilms tumor risk. Carriers of the rs1853259 G variant are less susceptible to developing Wilms tumor, with an adjusted OR of 0.78 (AG vs. AA: 95% CI = 0.61-0.995, P = 0.046). Single locus analysis of rs9457712 G > A and rs7766006 G > T, as well as the combined analysis of risk genotypes, failed to unveil an association with Wilms tumor risk, respectively. Stratified analysis of the three SNPs and their combined risk effects showed more significant relationships with Wilms tumor risk under certain subgroups. In all, we found weak evidence of the association between WTAP gene SNPs and the risk of Wilms tumor. Further replication studies with greater sample size and different ethnicities are necessary to verify our findings.

m6A RNA Methylation: Ramifications for Gene Expression and Human Health

Cellular transcriptomes are frequently adorned by a variety of chemical modification marks, which in turn have a profound influence on its functioning. Of these modifications, the one which has invited a lot of attention in the recent years is m6A RNA methylation, leading to the development of RNA epigenetics or epitranscriptomics as a frontier research area. m6A RNA methylation is one of the most abundant reversible internal modification seen in cellular RNAs. Studies in the last few years have not only shed light on the molecular machinery involved in m6A RNA methylation but also on the impact of this modification in regulating gene expression and hence biological processes. In this review, we will emphasize the biological impact of this modification in normal organismal development and diseases.

The potential role of RNA N6-methyladenosine in Cancer progression

N6-methyladenosine (m6A) is considered the most common, abundant, and conserved internal transcript modification, especially in eukaryotic messenger RNA (mRNA). m6A is installed by m6A methyltransferases (METTL3/14, WTAP, RBM15/15B, VIRMA and ZC3H13, termed “writers”), removed by demethylases (FTO, ALKBH5, and ALKBH3, termed “erasers”), and recognized by m6A-binding proteins (YTHDC1/2, YTHDF1/2/3, IGF2BP1/2/3, HNRNP, and eIF3, termed “readers”). Accumulating evidence suggests that m6A RNA methylation greatly impacts RNA metabolism and is involved in the pathogenesis of many kinds of diseases, including cancers. In this review, we focus on the physiological functions of m6A modification and its related regulators, as well as on the potential biological roles of these elements in human tumors.

m6A Modification in Coding and Non-coding RNAs: Roles and Therapeutic Implications in Cancer

N⁶-Methyladenosine (m⁶A) RNA modification has emerged in recent years as a new layer of regulatory mechanism controlling gene expression in eukaryotes. As a reversible epigenetic modification found not only in messenger RNAs but also in non-coding RNAs, m⁶A affects the fate of the modified RNA molecules and plays important roles in almost all vital bioprocesses, including cancer development. Here we review the up-to-date knowledge of the pathological roles and underlying molecular mechanism of m⁶A modifications (in both coding and non-coding RNAs) in cancer pathogenesis and drug response/resistance, and discuss the therapeutic potential of targeting m⁶A regulators for cancer therapy.

N6-Methyladenosine: A Potential Breakthrough for Human Cancer

Among more than 100 types of identified RNA modification, N6-methyladenosine (m6A) modification is the predominant mRNA modification, which regulates RNA splicing, translocation, stability, and translation. m6A modification plays critical roles in the growth, differentiation, and metabolism of cells. As a dynamic and reversible modification, m6A is catalyzed by "writers" (RNA methyltransferases), removed by "erasers" (demethylases), and interacts with "readers" (m6A-binding proteins). With more advanced technology applied to research, the molecular mechanisms of RNA methyltransferase, demethylase, and m6A-binding protein have been revealed. An increasing number of studies have implicated the correlation between m6A modification and human cancers. In this review, we summarize that the occurrence and development of various human cancers are associated with aberrant m6A modification. We also discuss the progress in research related to m6A modification, providing novel therapeutic insight and potential breakthrough in anticancer therapy.

N6-Adenosine Methylation in RNA and a Reduced m3G/TMG Level in Non-Coding RNAs Appear at Microirradiation-Induced DNA Lesions

The DNA damage response is mediated by both DNA repair proteins and epigenetic markers. Here, we observe that N⁶-methyladenosine (m⁶A), a mark of the epitranscriptome, was common in RNAs accumulated at UV-damaged chromatin; however, inhibitors of RNA polymerases I and II did not affect the m⁶A RNA level at the irradiated genomic regions. After genome injury, m⁶A RNAs either diffused to the damaged chromatin or appeared at the lesions enzymatically. DNA damage did not change the levels of METTL3 and METTL14 methyltransferases. In a subset of irradiated cells, only the METTL16 enzyme, responsible for m⁶A in non-coding RNAs as well as for splicing regulation, was recruited to microirradiated sites. Importantly, the levels of the studied splicing factors were not changed by UVA light. Overall, if the appearance of m⁶A RNAs at DNA lesions is regulated enzymatically, this process must be mediated via the coregulatory function of METTL-like enzymes. This event is additionally accompanied by radiation-induced depletion of 2,2,7-methylguanosine (m₃G/TMG) in RNA. Moreover, UV-irradiation also decreases the global cellular level of N¹-methyladenosine (m¹A) in RNAs. Based on these results, we prefer a model in which m⁶A RNAs rapidly respond to radiation-induced stress and diffuse to the damaged sites. The level of both (m¹A) RNAs and m₃G/TMG in RNAs is reduced as a consequence of DNA damage, recognized by the nucleotide excision repair mechanism.

YTHDF1 rs6090311 A>G polymorphism reduces Hepatoblastoma risk: Evidence from a seven-center case-control study

Various factors modulate the risk of hepatoblastoma. In this study, we aimed to investigate whether single nucleotide polymorphisms (SNPs) in the YTHDF1 gene could predispose to hepatoblastoma. We used TaqMan assay to genotype two YTHDF1 SNPs (rs6011668 C>T and rs6090311 A>G) in a Chinese population composed of 313 subjects with hepatoblastoma and 1446 controls from seven hospitals. We then evaluated the associations of these two SNPs with hepatoblastoma risk using unconditional logistic regression. We found that rs6090311 G allele exhibited a significant association with decreased hepatoblastoma risk [AG vs. AA: adjusted odds ratio (OR)=0.75; 95% confidence interval (CI)=0.58-0.98, P=0.033; AG/GG vs. AA: adjusted OR=0.76, 95% CI=0.59-0.97, P=0.029]. Furthermore, the combined analysis of protective genotypes revealed that subjects carrying two protective genotypes were less likely to have hepatoblastoma than those with 0-1 protective genotypes (adjusted OR=0.75, 95% CI=0.59-0.96, P=0.022). Subjects ≥17 months of age had decreased hepatoblastoma risk, in case that they carried rs6090311 AG/GG (adjusted OR=0.63, 95% CI=0.44-0.91, P=0.012), or two protective genotypes (adjusted OR=0.63, 95% CI=0.44-0.91, P=0.012). False-positive report probability analysis validated the reliability of the significant results. Preliminary functional annotations revealed that rs6090311 G was correlated with decreased expression of its surrounding genes in the expression quantitative trait locus (eQTL) analysis. In conclusion, our results indicate that the rs6090311 A>G in the YTHDF1 gene is related to decreased hepatoblastoma risk.

Multiple Functions and Mechanisms Underlying the Role of METTL3 in Human Cancers

Methyltransferase-like 3 (METTL3), a predominantly catalytic enzyme in the N⁶-methyladenosine (m⁶A) methyltransferase system, is dysregulated and plays a dual role (oncogene or tumor suppressor) in different human cancers. The expression and pro- or anticancer role of METTL3 in different cancers remain controversial. METTL3 is implicated in many aspects of tumor progression, including tumorigenesis, proliferation, invasion, migration, cell cycle, differentiation, and viability. Most underlying mechanisms involve multiple signaling pathways that rely on m⁶A-dependent modification. However, METTL3 can also modulate the cancer process by directly promoting the translation of oncogenes via interaction with the translation initiation machinery through recruitment of eukaryotic translation initiation factor 3 subunit h (eIF3h). In this review, we summarized the current evidence on METTL3 in diverse human malignancies and its potential as a prognostic/ therapeutic target.

RNA m6A Methyltransferase METTL3 Promotes The Growth Of Prostate Cancer By Regulating Hedgehog Pathway

Purpose

N⁶-methyladenosine (m⁶A) is the most abundant internal modification on eukaryotic mRNA and gained increasing attention recently. More and more evidence suggest that m⁶A methylation plays crucial role in tumor genesis and development. However, its role in prostate cancer remains largely unknown.

Methods

METTL3 expression status in prostate cancer was analyzed by using TCGA database and Western blotting. m⁶A content was analyzed by using RNA Methylation Quantification Kit. The role of METTL3 in prostate cancer cells was determined by proliferation, survival, colony formation, and invasion assays. The m⁶A level of GLI1 RNA was detected by methylated RNA immunoprecipitation (MeRIP) assay. In vivo role of METTL3 was studied on xenograft models.

Results

We found that m⁶A methyltransferase METTL3 was overexpressed in prostate cancer cell lines, together with increased m⁶A content. Functionally, silencing of METTL3 by shRNA in prostate cancer cell lines resulted in decreased m⁶A content, cell proliferation, survival, colony formation, and invasion. Interestingly, overexpression of wild-type METTL3 abrogated the repression effect of METTL3 depletion on m⁶A content, cell proliferation, survival, colony formation, and invasion, while the overexpression of m⁶A catalytic site mutant METTL3 was unable to rescue the inhibitory effect caused by METTL3 depletion. Further mechanism analysis demonstrated that METTL3 silence decreased the m⁶A modification and expression of GLI1, an important component of hedgehog pathway, which led to cell apoptosis. Moreover, depletion of METTL3 inhibited tumor growth in vivo.

Conclusion

Our results suggested that the m⁶A methyltransferase METTL3 promotes the growth and motility of prostate cancer cells by regulating hedgehog pathway.

Potential MMP2-mediated availability of HLA binding, mutant ECM peptides reflects better melanoma survival rates and greater T-cell infiltrates

Proteases in the cancer microenvironment have been studied for some time, with a general conclusion that such proteases facilitate the spread of cancer, although there is some controversy regarding that conclusion in later-stage cancer development. More recently, a very large collection of data regarding mutant amino acids in the potential substrates of cancer microenvironment proteases have become available. To better understand the potential impact of these mutant amino acids on protease function and cancer progression, we established a bioinformatics approach to assessing the impact of melanoma mutants, among a previously defined set of extracellular matrix (ECM) structural proteins, on the sensitivity of matrix metalloproteinase-2 (MMP2), extensively associated with melanoma. The results indicated that tumor samples with mutant amino acids adjacent to the ECM structural protein, MMP2 sites also represented a better survival rate and a larger proportion of mutant peptides with high HLA class I-binding affinities, particularly in comparison with melanoma samples with a reduced or absent T-cell infiltrate. Furthermore, even better HLA class I binders were identified among the samples representing the ECM structural protein mutants resistant to MMP2. Samples representing only MMP2-resistant mutants also represented a worse overall survival. Overall, this analysis suggested that MMP2 has the capacity of freeing mutant peptides that could facilitate an anti-tumor response and a better survival rate, and this analysis has the potential of resolving some of the controversy surrounding the role of cancer proteases in cancer progression.