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

METTL3 Modulates Ctsk+ Lineage Supporting Cranial Osteogenesis via Hedgehog

N6-methyladenosine (m6A) modification, a eukaryotic messenger RNA modification catalyzed by methyltransferase-like 3 (METTL3), plays a pivotal role in stem cell fate determination. Calvarial bone development and maintenance are orchestrated by the cranial sutures. Cathepsin K (CTSK)-positive calvarial stem cells (CSCs) contribute to mice calvarial ossification. However, the role of m6A modification in regulating Ctsk+ lineage cells during calvarial development remains elusive. Here, we showed that METTL3 was colocalized with cranial nonosteoclastic Ctsk+ lineage cells, which were also associated with GLI1 expression. During neonatal development, depletion of Mettl3 in the Ctsk+ lineage cells delayed suture formation and decreased mineralization. During adulthood maintenance, loss of Mettl3 in the Ctsk+ lineage cells impaired calvarial bone formation, which was featured by the increased bone porosity, enhanced bone marrow cavity, and decreased number of osteocytes with the less-developed cellular outline. The analysis of methylated RNA immunoprecipitation sequencing and RNA sequencing data indicated that loss of METTL3 reduced Hedgehog (Hh) signaling pathway. Restoration of Hh signaling pathway by crossing Sufufl/+ alleles or by local administration of SAG21 partially rescued the abnormity. Our data indicate that METTL3 modulates Ctsk+ lineage cells supporting calvarial bone formation by regulating the Hh signaling pathway, providing new insights for clinical treatment of skull vault osseous diseases.

N6-Methyladenosine Methylation of mRNA in Cell Apoptosis

Apoptosis, a highly controlled homeostatic mechanism that eliminates single cells without destroying tissue function, occurs during growing development and senescence. N6-methyladenosine (m6A), as the most common internal modification of eukaryotic mRNA, fine-tunes gene expression by regulating many aspects of mRNA metabolism, such as splicing, nucleation, stability, translation, and degradation. Remarkably, recent reports have indicated that aberrant methylation of m6A-related RNA may directly or indirectly influence the expression of apoptosis-related genes, thus regulating the process of cell apoptosis. In this review, we summarized the relationship between m6A modification and cell apoptosis, especially its role in the nervous system, and analyzed the limitations of the current research.

Role of N6‑methyladenosine in the pathogenesis, diagnosis and treatment of prostate cancer (Review)

Prostate cancer (PCa) affects males of all racial and ethnic groups, and leads to higher rates of mortality in those belonging to a lower socioeconomic status due to the late detection of the disease. PCa affects middle‑aged males between the ages of 45 and 60 years, and is the highest cause of cancer‑associated mortality in Western countries. As the most abundant and common mRNA modification in higher eukaryotes, N6‑methyladenosine (m6A) is widely distributed in mammalian cells and influences various aspects of mRNA metabolism. Recent studies have found that abnormal expression levels of various m6A regulators significantly affect the development and progression of various types of cancer, including PCa. The present review discusses the influence of m6A regulatory factors on the pathogenesis and progression of PCa through mRNA modification based on the current state of research on m6A methylation modification in PCa. It is considered that the treatment of PCa with micro‑molecular drugs that target the epigenetics of the m6A regulator to correct abnormal m6A modifications is a direction for future research into current diagnostic and therapeutic approaches for PCa.

Bioinformatics analysis and experimental validation of m6A and cuproptosis-related lncRNA NFE4 in clear cell renal cell carcinoma

PURPOSE

This study aimed to construct an m6A and cuproptosis-related long non-coding RNAs (lncRNAs) signature to accurately predict the prognosis of kidney clear cell carcinoma (KIRC) patients using the information acquired from The Cancer Genome Atlas (TCGA) database.

METHODS

First, the co-expression analysis was performed to identify lncRNAs linked with N6-methyladenosine (m6A) and cuproptosis in ccRCC. Then, a model encompassing four candidate lncRNAs was constructed via univariate, least absolute shrinkage together with selection operator (LASSO), and multivariate regression analyses. Furthermore, Kaplan-Meier, principal component, functional enrichment annotation, and nomogram analyses were performed to develop a risk model that could effectively assess medical outcomes for ccRCC cases. Moreover, the cellular function of NFE4 in Caki-1/OS-RC-2 cultures was elucidated through CCK-8/EdU assessments and Transwell experiments. Dataset outcomes indicated that NFE4 can have possible implications in m6A and cuproptosis, and may promote ccRCC progression.

RESULTS

We constructed a panel of m6A and cuproptosis-related lncRNAs to construct a prognostic prediction model. The Kaplan-Meier and ROC curves showed that the feature had acceptable predictive validity in the TCGA training, test, and complete groups. Furthermore, the m6A and cuproptosis-related lncRNA model indicated higher diagnostic efficiency than other clinical features. Moreover, the NFE4 function analysis indicated a gene associated with m6A and cuproptosis-related lncRNAs in ccRCC. It was also revealed that the proliferation and migration of Caki-1 /OS-RC-2 cells were inhibited in the NFE4 knockdown group.

CONCLUSION

Overall, this study indicated that NFE4 and our constructed risk signature could predict outcomes and have potential clinical value.

Internal m 6 A and m 7 G RNA modifications in hematopoietic system and acute myeloid leukemia

ABSTRACT

Epitranscriptomics focuses on the RNA-modification-mediated post-transcriptional regulation of gene expression. The past decade has witnessed tremendous progress in our understanding of the landscapes and biological functions of RNA modifications, as prompted by the emergence of potent analytical approaches. The hematopoietic system provides a lifelong supply of blood cells, and gene expression is tightly controlled during the differentiation of hematopoietic stem cells (HSCs). The dysregulation of gene expression during hematopoiesis may lead to severe disorders, including acute myeloid leukemia (AML). Emerging evidence supports the involvement of the mRNA modification system in normal hematopoiesis and AML pathogenesis, which has led to the development of small-molecule inhibitors that target N6-methyladenosine (m 6 A) modification machinery as treatments. Here, we summarize the latest findings and our most up-to-date information on the roles of m 6 A and N7-methylguanine in both physiological and pathological conditions in the hematopoietic system. Furthermore, we will discuss the therapeutic potential and limitations of cancer treatments targeting m 6 A.

Positive GLI1/INHBA feedback loop drives tumor progression in gastric cancer

GLI1, a key transcription factor of the Hedgehog (Hh) signaling pathway, plays an important role in the development of cancer. However, the function and mechanisms by which GLI1 regulates gene transcription are not fully understood in gastric cancer (GC). Here, we found that GLI1 induced the proliferation and metastasis of GC cells, accompanied by transcriptional upregulation of INHBA. This increased INHBA expression exerted a promoting activity on Smads signaling and then transcriptionally activated GLI1 expression. Notably, our results demonstrate that disrupting the interaction between GLI1 and INHBA could inhibit GC tumorigenesis in vivo. More intriguingly, we confirmed the N6-methyladenosine (m6A) activation mechanism of the Helicobacter pylori/FTO/YTHDF2/GLI1 pathway in GC cells. In conclusion, our study confirmed that the GLI1/INHBA positive feedback loop influences GC progression and revealed the mechanism by which H. pylori upregulates GLI1 expression through m6A modification. This positive GLI1/INHBA feedback loop suggests a novel noncanonical mechanism of GLI1 activity in GC and provides potential therapeutic targets for GC treatment.

The relationship between the network of non-coding RNAs-molecular targets and N6-methyladenosine modification in tumors of urinary system

N6-methyladenosine (m6A) methylation, a prevalent eukaryotic post-transcriptional modification, is involved in multiple biological functions, including mediating variable splicing, RNA maturation, transcription, and nuclear export, and also is vital for regulating RNA translation, stability, and cytoplasmic degradation. For example, m6A methylation can regulate pre-miRNA expression by affecting both splicing and maturation. Non-coding RNA (ncRNA), which includes microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), does not encode proteins but has powerful impacts on transcription and translation. Conversely, ncRNAs may impact m6A methylation by affecting the expression of m6A regulators, including miRNAs targeting mRNA of m6A regulators, or lncRNAs, and circRNAs, acting as scaffolds to regulate transcription of m6A regulatory factors. Dysregulation of m6A methylation is common in urinary tumors, and the regulatory role of ncRNAs is also important for these malignancies. This article provides a systematic review of the role and mechanisms of action of m6A methylation and ncRNAs in urinary tumors.

β-hydroxybutyrate inhibits malignant phenotypes of prostate cancer cells through β-hydroxybutyrylation of indoleacetamide-N-methyltransferase

BACKGROUND

Prostate cancer (PCa) is one of the most prevalent cancers in men and is associated with high mortality and disability rates. β-hydroxybutyrate (BHB), a ketone body, has received increasing attention for its role in cancer. However, its role in PCa remains unclear. This study aimed to explore the mechanism and feasibility of BHB as a treatment alternative for PCa.

METHODS

Colony formation assay, flow cytometry, western blot assay, and transwell assays were performed to determine the effect of BHB on the proliferation and metastasis of PCa cells. Tumor sphere formation and aldehyde dehydrogenase assays were used to identify the impact of BHB or indoleacetamide-N-methyltransferase (INMT) on the stemness of PCa cells. N6-methyladenosine (m6A)-meRIP real-time reverse transcription polymerase chain reaction and dual luciferase assays were conducted to confirm INMT upregulation via the METTL3-m6A pathway. Co-IP assay was used to detect the epigenetic modification of INMT by BHB-mediated β-hydroxybutyrylation (kbhb) and screen enzymes that regulate INMT kbhb. Mouse xenograft experiments demonstrated the antitumor effects of BHB in vivo.

RESULTS

BHB can inhibit the proliferation, migration, and invasion of PCa cells by suppressing their stemness. Mechanistically, INMT, whose expression is upregulated by the METTL3-m6A pathway, was demonstrated to be an oncogenic gene that promotes the stem-like characteristics of PCa cells. BHB can suppress the malignant phenotypes of PCa by kbhb of INMT, which in turn inhibits INMT expression.

CONCLUSIONS

Our findings indicate a role of BHB in PCa metabolic therapy, thereby suggesting an epigenetic therapeutic strategy to target INMT in aggressive PCa.

TRIAL REGISTRATION

Not applicable.

Bridging tissue repair and epithelial carcinogenesis: epigenetic memory and field cancerization

The epigenome coordinates spatial-temporal specific gene expression during development and in adulthood, for the maintenance of homeostasis and upon tissue repair. The upheaval of the epigenetic landscape is a key event in the onset of many pathologies including tumours, where epigenetic changes cooperate with genetic aberrations to establish the neoplastic phenotype and to drive cell plasticity during its evolution. DNA methylation, histone modifiers and readers or other chromatin components are indeed often altered in cancers, such as carcinomas that develop in epithelia. Lining the surfaces and the cavities of our body and acting as a barrier from the environment, epithelia are frequently subjected to acute or chronic tissue damages, such as mechanical injuries or inflammatory episodes. These events can activate plasticity mechanisms, with a deep impact on cells' epigenome. Despite being very effective, tissue repair mechanisms are closely associated with tumour onset. Here we review the similarities between tissue repair and carcinogenesis, with a special focus on the epigenetic mechanisms activated by cells during repair and opted by carcinoma cells in multiple epithelia. Moreover, we discuss the recent findings on inflammatory and wound memory in epithelia and describe the epigenetic modifications that characterise them. Finally, as wound memory in epithelial cells promotes carcinogenesis, we highlight how it represents an early step for the establishment of field cancerization.

The role of the methyltransferase METTL3 in prostate cancer: a potential therapeutic target

The incidence of prostate cancer (PCa), the most prevalent malignancy, is currently at the forefront. RNA modification is a subfield of the booming field of epigenetics. To date, more than 170 types of RNA modifications have been described, and N6-methyladenosine (m6A) is the most abundant and well-characterized internal modification of mRNAs involved in various aspects of cancer progression. METTL3, the first identified key methyltransferase, regulates human mRNA and non-coding RNA expression in an m6A-dependent manner. This review elucidates the biological function and role of METTL3 in PCa and discusses the implications of METTL3 as a potential therapeutic target for future research directions and clinical applications.

The role of RNA modification in urological cancers: mechanisms and clinical potential

RNA modification is a post-transcriptional level of regulation that is widely distributed in all types of RNAs, including mRNA, tRNA, rRNA, miRNA, and lncRNA, where N6-methyladenine (m6A) is the most abundant mRNA methylation modification. Significant evidence has depicted that m6A modifications are closely related to human diseases, especially cancer, and play pivotal roles in RNA transcription, splicing, stabilization, and translation processes. The most common urological cancers include prostate, bladder, kidney, and testicular cancers, accounting for a certain proportion of human cancers, with an ever-increasing incidence and mortality. The recurrence, systemic metastasis, poor prognosis, and drug resistance of urologic tumors have prompted the identification of new therapeutic targets and mechanisms. Research on m6A modifications may provide new solutions to the current puzzles. In this review, we provide a comprehensive overview of the key roles played by RNA modifications, especially m6A modifications, in urologic cancers, as well as recent research advances in diagnostics and molecularly targeted therapies.

RNA N6-methyladenosine-modified-binding protein YTHDF1 promotes prostate cancer progression by regulating androgen function-related gene TRIM68

PURPOSE

There is no report about the direct relationship between m6A modification and androgen receptor (AR)-related genes in prostate cancer (PC). We aimed to study the mechanisms of m6A methylation in regulating the pathogenesis of PC from the perspective of AR-related genes.

METHODS

qRT-PCR was applied to detect the expression of m6A-related genes in PC cell with or without AR inhibitor. The effects of YTHDF1 knockdown on PC cell viability, apoptosis, migration and invasion were investigated using flow cytometry, wound healing and transwell assays, respectively. The mechanism of YTHDF1 action was investigated using m6A RNA immunoprecipitation (MeRIP) sequencing. The biological functions of YTHDF1 were also explored through in vivo experiments.

RESULTS

YTHDF1 was significantly down-regulated in AR inhibitor group. YTHDF1 knockdown significantly decreased AR level, viability and m6A methylation level of PC cells. TRIM68 was identified as a direct target of YTHDF1. Both YTHDF1 and TRIM68 knockdown increased apoptosis, and decreased cell viability, migration, and invasion of PC cells, while TRIM68 overexpression reversed the effects of YTHDF1 knockdown on PC cells. In addition, knockdown of YTHDF1 or TRIM68 significantly decreased the m6A methylation level, and mRNA and protein levels of YTHDF1, TRIM68 and AR in PC cells, while TRIM68 overexpression increased the expression levels above. Furthermore, subcutaneous xenografts of nude mice also revealed that TRIM68 could reverse the effects of YTHDF1 knockdown in PC in vivo.

CONCLUSION

This study suggested the key role of YTHDF1-mediated m6A modification in PC progression by regulating androgen function-related gene TRIM68 in PC.

Interpretable prediction models for widespread m6A RNA modification across cell lines and tissues

MOTIVATION

RNA N6-methyladenosine (m6A) in Homo sapiens plays vital roles in a variety of biological functions. Precise identification of m6A modifications is thus essential to elucidation of their biological functions and underlying molecular-level mechanisms. Currently available high-throughput single-nucleotide-resolution m6A modification data considerably accelerated the identification of RNA modification sites through the development of data-driven computational methods. Nevertheless, existing methods have limitations in terms of the coverage of single-nucleotide-resolution cell lines and have poor capability in model interpretations, thereby having limited applicability.

RESULTS

In this study, we present CLSM6A, comprising a set of deep learning-based models designed for predicting single-nucleotide-resolution m6A RNA modification sites across eight different cell lines and three tissues. Extensive benchmarking experiments are conducted on well-curated datasets and accordingly, CLSM6A achieves superior performance than current state-of-the-art methods. Furthermore, CLSM6A is capable of interpreting the prediction decision-making process by excavating critical motifs activated by filters and pinpointing highly concerned positions in both forward and backward propagations. CLSM6A exhibits better portability on similar cross-cell line/tissue datasets, reveals a strong association between highly activated motifs and high-impact motifs, and demonstrates complementary attributes of different interpretation strategies.

AVAILABILITY AND IMPLEMENTATION

The webserver is available at http://csbio.njust.edu.cn/bioinf/clsm6a. The datasets and code are available at https://github.com/zhangying-njust/CLSM6A/.

RNA m6A modification in prostate cancer: A new weapon for its diagnosis and therapy

Prostate cancer (PCa) is the most common malignant tumor and the second leading cause of cancer-related mortality in men worldwide. Despite significant advances in PCa therapy, the underlying molecular mechanisms have yet to be fully elucidated. Recently, epigenetic modification has emerged as a key player in tumor progression, and RNA-based N6-methyladenosine (m6A) epigenetic modification was found to be crucial. This review summarizes comprehensive state-of-art mechanisms underlying m6A modification, its implication in the pathogenesis, and advancement of PCa in protein-coding and non-coding RNA contexts, its relevance to PCa immunotherapy, and the ongoing clinical trials for PCa treatment. This review presents potential m6A-based targets and paves a new avenue for diagnosing and treating PCa, providing new guidelines for future related research through a systematic review of previous results.

Dissecting the effects of METTL3 on alternative splicing in prostate cancer

Although the role of METTL3 has been extensively studied in many cancers, its role in isoform switching in prostate cancer (PCa) has been poorly explored. To investigate its role, we applied standard RNA-sequencing and long-read direct RNA-sequencing from Oxford Nanopore to examine how METTL3 affects alternative splicing (AS) in two PCa cell lines. By dissecting genome-wide METTL3-regulated AS events, we noted that two PCa cell lines (representing two different PCa subtypes, androgen-sensitive or resistant) behave differently in exon skipping and intron retention events following METTL3 depletion, suggesting AS heterogeneity in PCa. Moreover, we revealed that METTL3-regulated AS is dependent on N6-methyladenosine (m6A) and distinct splicing factors. Analysis of the AS landscape also revealed cell type specific AS signatures for some genes (e.g., MKNK2) involved in key functions in PCa tumorigenesis. Finally, we also validated the clinical relevance of MKNK2 AS events in PCa patients and pointed to the possible regulatory mechanism related to m6A in the exon14a/b region and SRSF1. Overall, we characterize the role of METTL3 in regulating PCa-associated AS programs, expand the role of METTL3 in tumorigenesis, and suggest that MKNK2 AS events may serve as a new potential prognostic biomarker.

Connecting the Dots: N6-Methyladenosine (m6 A) Modification in Spermatogenesis

N6-methyladenosine (m6 A) is the most common RNA modification found in eukaryotes and is involved in multiple biological processes, including neuronal development, tumorigenesis, and gametogenesis. It is well known that methylation-modifying enzymes (classified into writers, erasers, and readers) mediate catalysis, clearance, and recognition of m6 A. Recent studies suggest that these genes may be associated with spermatogenesis. Numerous studies have revealed the m6 A role during spermatogenesis. However, the expression patterns and relationships of these m6 A enzymes during various stages of spermatogenesis remain unknown. In this review, it is aimed to provide an overview of m6 A enzyme functions and elucidate their potential mechanisms and regulatory relationships at a specific phase during spermatogenesis, providing new insights into the m6 A modification underlying the spermatogenesis process.

Methyltransferase-like 3 enhances cell proliferation and cisplatin resistance in natural killer/T-cell lymphoma through promoting N6-methyladenosine modification and the stability of staphylococcal nuclease and Tudor domain-containing protein 1 mRNA

Nasal-type natural killer/T-cell lymphoma (NKTCL) is a typical class of non-Hodgkin's lymphoma, which is quite malignant because of its high resistance to chemotherapy. N6-methyladenosine (m6A) modification, a prevalent modification of eukaryotic RNA, was emerging as an important regulatory mechanism in progression of various tumors. Here, we demonstrated that methyltransferase-like 3 (METTL3), an RNA methyltransferase, was obviously upregulated in human NKTCL cell lines (NK-92, YTS, SNT-8, and SNK-6) compared with normal NK cells. Knockdown of METTL3 noticeably repressed proliferation and facilitated apoptosis in SNT-8 cells, whereas overexpression of METTL3 showed opposite results in SNK-6 cells. In the mechanism exploration, we found that METTL3 stimulated the m6A modification of staphylococcal nuclease and Tudor domain-containing protein 1 (SND1) mRNA, recruited YTH m6A RNA binding protein 1 to recognize the m6A site, thereby enhancing its mRNA stability. Rescue experiments demonstrated that METTL3 significantly prohibited NKTCL cell chemotherapy sensitivity to cisplatin (DDP) through regulating SND1 expression. Furthermore, knockdown of SND1 suppressed tumor growth and reduced DDP resistance in vivo . Taken together, our findings uncovered the role of METTL3 in the regulation of chemotherapy resistance in NKTCL oncogenesis.

The emerging roles and mechanism of N6-methyladenosine (m6A) modifications in urologic tumours progression

Prostate cancer (PCa), bladder cancer (BC), and renal cell cancer (RCC) are the most common urologic tumours in males. N6-methyladenosine (m⁶A), adenosine N6 methylation, is the most prevalent RNA modification in mammals. Increasing evidence suggests that m⁶A plays a crucial role in cancer development. In this review, we comprehensively analyzed the influence of m⁶A methylation on Prostate cancer, bladder cancer, and renal cell cancer and the relationship between the expression of relevant regulatory factors and their development and occurrence, which provides new insights and approaches for the early clinical diagnosis and targeted therapy of urologic malignancies.

Novel insights into the METTL3-METTL14 complex in musculoskeletal diseases

N6-methyladenosine (m⁶A) modification, catalyzed by methyltransferase complexes (MTCs), plays many roles in multifaceted biological activities. As the most important subunit of MTCs, the METTL3-METTL14 complex is reported to be the initial factor that catalyzes the methylation of adenosines. Recently, accumulating evidence has indicated that the METTL3-METTL14 complex plays a key role in musculoskeletal diseases in an m⁶A-dependent or -independent manner. Although the functions of m⁶A modifications in a variety of musculoskeletal diseases have been widely recognized, the critical role of the METTL3-METTL14 complex in certain musculoskeletal disorders, such as osteoporosis, osteoarthritis, rheumatoid arthritis and osteosarcoma, has not been systematically revealed. In the current review, the structure, mechanisms and functions of the METTL3-METTL14 complex and the mechanisms and functions of its downstream pathways in the aforementioned musculoskeletal diseases are categorized and summarized.

N6-methyladenine-mediated aberrant activation of the lncRNA SOX2OT-GLI1 loop promotes non-small-cell lung cancer stemness

Despite the advent of precision medicine and immunotherapy, mortality due to lung cancer remains high. The sonic hedgehog (SHH) cascade and its key terminal factor, glioma-associated oncogene homolog 1 (GLI1), play a pivotal role in the stemness and drug resistance of lung cancer. Here, we investigated the molecular mechanism of non-canonical aberrant GLI1 upregulation. The SHH cascade was upregulated in stem spheres and chemo-resistant lung cancer cells and was accountable for drug resistance against multiple chemotherapy regimens. GLI1 and the long non-coding RNA SOX2OT were positively regulated, and the GLI1-SOX2OT loop mediated the proliferation of parental and stem-like lung cancer cells. Further mechanistic investigation revealed that SOX2OT facilitated METTL3/14/IGF2BP2-mediated m6A modification and stabilization of the GLI1 mRNA. Additionally, SOX2OT upregulated METTL3/14/IGF2BP2 by sponging miR-186-5p. Functional analysis corroborated that GLI1 acted as a downstream target of METTL3/14/IGF2BP2, and GLI1 silencing could block the oncogenicity of lung cancer stem-like cells. Pharmacological inhibition of the loop remarkably inhibited the oncogenesis of lung cancer cells in vivo. Compared with paired adjacent normal tissues, lung cancer specimens exhibited consistently upregulated GLI1/SOX2OT/METTL3/14/IGF2BP2. The m6A-modified GLI1-SOX2OT loop may serve as a potential therapeutic target and prognostic predictor for lung cancer therapy and diagnosis in the clinic.

TEAD3 inhibits the proliferation and metastasis of prostate cancer via suppressing ADRBK2

TEAD3 acts as a transcription factor in many tumors to promote tumor occurrence and development. But in prostate cancer (PCa), it appears as a tumor suppressor gene. Recent studies have shown that this may be related to subcellular localization and posttranslational modification. We found that TEAD3 was down-expressed in PCa. Immunohistochemistry of clinical PCa specimens confirmed that TEAD3 expression was the highest in benign prostatic hyperplasia (BPH) tissues, followed by primary PCa tissues, and the lowest in metastatic PCa tissues, and its expression level was positively correlated with overall survival. MTT assay, clone formation assay, and scratch assay confirmed that overexpression of TEAD3 could significantly inhibit the proliferation and migration of PCa cells. Next-generation sequencing results indicated that Hedgehog (Hh) signaling pathway was significantly inhibited after overexpression of TEAD3. Rescue assays suggested that ADRBK2 could reverse the proliferation and migration ability caused by overexpression of TEAD3. TEAD3 is downregulated in PCa and associated with poor patient prognosis. Overexpression of TEAD3 inhibits the proliferation and migration ability of PCa cells via restraining the mRNA level of ADRBK2. These results indicate that TEAD3 was down-expressed in PCa patients and was positively correlated with a high Gleason score and poor prognosis. Mechanistically, we found that the upregulation of TEAD3 inhibits the proliferation and metastasis of prostate cancer by inhibiting the expression of ADRBK2.

METTL3 from Target Validation to the First Small-Molecule Inhibitors: A Medicinal Chemistry Journey

RNA methylation is a critical mechanism for regulating the transcription and translation of specific sequences or for eliminating unnecessary sequences during RNA maturation. METTL3, an RNA methyltransferase that catalyzes the transfer of a methyl group to the N⁶-adenosine of RNA, is one of the key mediators of this process. METTL3 dysregulation may result in the emergence of a variety of diseases ranging from cancer to cardiovascular and neurological disorders beyond contributing to viral infections. Hence, the discovery of METTL3 inhibitors may assist in furthering the understanding of the biological roles of this enzyme, in addition to contributing to the development of novel therapeutics. Through this work, we will examine the existing correlations between METTL3 and diseases. We will also analyze the development, mode of action, pharmacology, and structure-activity relationships of the currently known METTL3 inhibitors. They include both nucleoside and non-nucleoside compounds, with the latter comprising both competitive and allosteric inhibitors.

RNA modification writers pattern in relation to tumor microenvironment and prognosis in prostate cancer

Background: RNA modifications are important in the study of epigenetic regulatory mechanisms in immune responses and tumorigenesis. When RNA writers are mutated or disrupted in expression, the genes associated with the pathways they modify are also disrupted and can activate or repress related pathways, affecting tumorigenesis and progression. However, the potential role of RNA writers in prostate cancer is unclear. Methods: Based on data from three datasets, we describe 26 RNA writers that mediate gene expression and genetic mutation in prostate cancer and assess their expression patterns in 948 prostate cancer samples. Using principal component analysis algorithms, the RM Score was developed to quantify the RNA modification patterns of specific tumors. Results: Two different categories were determined by unsupervised clustering methods, and survival analysis showed significant differences in OS prognosis between these two categories. Differentially expressed genes between the different categories were detected and the RNA writers-mediated scoring model RM_Score were constructed based on this. Also, the RM_Score was analyzed in relation to clinical characteristics, immune infiltration level, drug response, and efficacy of chemotherapy and immunotherapy. Those results confirm that multilayer alterations in epitope-modified RNA writers are associated with patient prognosis and with immune cell infiltration characteristics. Finally, we examined differentially expressed mRNA, lncRNA and miRNA between high and low RM_Score groups, based on which a ceRNA regulatory network was constructed. Conclusion: This work is a comprehensive analysis of modified writers in prostate cancer and identified them to have a role in chemotherapy and immunotherapy.

Clinical and molecular significance of the RNA m6A methyltransferase complex in prostate cancer

N⁶-methyladenosine (m⁶A) is the most abundant internal mRNA modification and is dynamically regulated through distinct protein complexes that methylate, demethylate, and/or interpret the m⁶A modification. These proteins, and the m⁶A modification, are involved in the regulation of gene expression, RNA stability, splicing and translation. Given its role in these crucial processes, m⁶A has been implicated in many diseases, including in cancer development and progression. Prostate cancer (PCa) is the most commonly diagnosed non-cutaneous cancer in men and recent studies support a role for m⁶A in PCa. Despite this, the literature currently lacks an integrated analysis of the expression of key components of the m⁶A RNA methyltransferase complex, both in PCa patients and in well-established cell line models. For this reason, this study used immunohistochemistry and functional studies to investigate the mechanistic and clinical significance of the METTL3, METTL14, WTAP and CBLL1 components of the m⁶A methyltransferase complex in PCa specimens and cell lines. Expression of METTL3 and CBLL1, but not METTL14 and WTAP, was associated with poorer PCa patient outcomes. Expression of METTL3, METTL14, WTAP and CBLL1 was higher in PCa cells compared with non-malignant prostate cells, with the highest expression seen in castrate-sensitive, androgen-responsive PCa cells. Moreover, in PCa cell lines, expression of METTL3 and WTAP was found to be androgen-regulated. To investigate the mechanistic role(s) of the m⁶A methyltransferase complex in PCa cells, short hairpin RNA (shRNA)-mediated knockdown coupled with next generation sequencing was used to determine the transcriptome-wide roles of METTL3, the catalytic subunit of the m⁶A methyltransferase complex. Functional depletion of METTL3 resulted in upregulation of the androgen receptor (AR), together with 134 AR-regulated genes. METTL3 knockdown also resulted in altered splicing, and enrichment of cell cycle, DNA repair and metabolic pathways. Collectively, this study identified the functional and clinical significance of four essential m⁶A complex components in PCa patient specimens and cell lines for the first time. Further studies are now warranted to determine the potential therapeutic relevance of METTL3 inhibitors in development to treat leukaemia to benefit patients with PCa.

The m6A methylation landscape, molecular characterization and clinical relevance in prostate adenocarcinoma

Background

Despite the recent progress of therapeutic strategies in treating prostate cancer (PCa), the majority of patients still eventually relapse, experiencing dismal outcomes. Therefore, it is of utmost importance to identify novel viable targets to increase the effectiveness of treatment. The present study aimed to investigate the potential relationship between N6-methyladenosine (m6A) RNA modification and PCa development and determine its clinical relevance.

Methods

Through systematic analysis of the TCGA database and other datasets, we analyzed the gene expression correlation and mutation profiles of m6A-related genes between PCa and normal tissues. Patient samples were divided into high- and low-risk groups based on the results of Least Absolute Shrinkage and Selection Operator (LASSO) Cox analysis. Subsequently, differences in biological processes and genomic characteristics of the two risk groups were determined, followed by functional enrichment analysis and gene set enrichment (GSEA) analysis. Next, we constructed the protein-protein interaction (PPI) network of differentially expressed genes between patients in high- and low-risk groups, along with the mRNA-miRNA-lncRNA network. The correlation analysis of tumor-infiltrating immune cells was further conducted to reveal the differences in immune characteristics between the two groups.

Results

A variety of m6A-related genes were identified to be differentially expressed in PCa tissues as compared with normal tissues. In addition, the PPI network contained 278 interaction relationships and 34 m6A-related genes, and the mRNA-miRNA-lncRNA network contained 17 relationships, including 91 miRNAs. Finally, the immune characteristics analysis showed that compared with the low-risk group, the levels of M1 and M2 macrophages in the high-risk group significantly increased, while the levels of mast cells resting and T cells CD4 memory resting significantly decreased.

Conclusions

This study provides novel findings that can further the understanding of the role of m6A methylation during the progression of PCa, which may facilitate the invention of targeted therapeutic drugs.

Recent Advances in RNA m6A Modification in Solid Tumors and Tumor Immunity

An analogous field to epigenetics is referred to as epitranscriptomics, which focuses on the study of post-transcriptional chemical modifications in RNA. RNA molecules, including mRNA, tRNA, rRNA, and other non-coding RNA molecules, can be edited with numerous modifications. The most prevalent modification in eukaryotic mRNA is N6-methyladenosine (m6A), which is a reversible modification found in over 7000 human genes. Recent technological advances have accelerated the characterization of these modifications, and they have been shown to play important roles in many biological processes, including pathogenic processes such as cancer. In this chapter, we discuss the role of m6A mRNA modification in cancer with a focus on solid tumor biology and immunity. m6A RNA methylation and its regulatory proteins can play context-dependent roles in solid tumor development and progression by modulating RNA metabolism to drive oncogenic or tumor-suppressive cellular pathways. m6A RNA methylation also plays dynamic roles within both immune cells and tumor cells to mediate the anti-tumor immune response. Finally, an emerging area of research within epitranscriptomics studies the role of m6A RNA methylation in promoting sensitivity or resistance to cancer therapies, including chemotherapy, targeted therapy, and immunotherapy. Overall, our understanding of m6A RNA methylation in solid tumors has advanced significantly, and continued research is needed both to fill gaps in knowledge and to identify potential areas of focus for therapeutic development.

Translational Regulation by eIFs and RNA Modifications in Cancer

Translation is a fundamental process in all living organisms that involves the decoding of genetic information in mRNA by ribosomes and translation factors. The dysregulation of mRNA translation is a common feature of tumorigenesis. Protein expression reflects the total outcome of multiple regulatory mechanisms that change the metabolism of mRNA pathways from synthesis to degradation. Accumulated evidence has clarified the role of an increasing amount of mRNA modifications at each phase of the pathway, resulting in translational output. Translation machinery is directly affected by mRNA modifications, influencing translation initiation, elongation, and termination or altering mRNA abundance and subcellular localization. In this review, we focus on the translation initiation factors associated with cancer as well as several important RNA modifications, for which we describe their association with cancer.

Functions and mechanisms of N6‑methyladenosine in prostate cancer (Review)

Prostate cancer (PCa) has long been a major public health problem affecting men worldwide. Even with treatment, it can develop into castration-resistant PCa. With the continuous advancement in epigenetics, researchers have explored N6-methyladenosine (m⁶A) in search of a more effective and lasting treatment for PCa. m⁶A is widely distributed in mammalian cells and influences various aspects of mRNA metabolism. Recently, it has been associated with the development or suppression of various types of cancer, including PCa. This review summarizes the recent findings on m⁶A regulation and its functions and mechanisms in cells, focusing on the various functional proteins operating within m⁶A in PCa cells. Moreover, the potential clinical value of exploiting m⁶A modification as an early diagnostic marker in PCa diagnosis and therapeutics was discussed. m⁶A may also be used as an indicator to evaluate treatment outcome and prognosis.

m6A Methylation Regulators Are Predictive Biomarkers for Tumour Metastasis in Prostate Cancer

Simple Summary

Recurrence and metastatic progression always lead to dismal outcomes in prostate cancer (PCa). There is no reliable biomarker for the prediction of recurrence and metastasis other than the Prostate Cancer Antigen (PCA). N6-methyladenosine (m⁶A) is the most common post-transcriptional mRNA modification and is regulated by m⁶A regulators dynamically. Since m⁶A modification is associated with cancer development and outgrowth, we performed a consensus clustering on PCa with regard to the gene expression of all m⁶A regulators. We identified three subtypes of Pca with distinct m⁶A expression patterns and enriched biological pathways. We also established an m⁶A score for metastasis prediction based on our clustering, which is potentially a predictive biomarker for Pca metastasis.

Abstract

Prostate cancer (PCa) is one of the most common cancers in men. Usually, most PCas at initial diagnosis are localized and hormone-dependent, and grow slowly. Patients with localized PCas have a nearly 100% 5-year survival rate; however, the 5-year survival rate of metastatic or progressive PCa is still dismal. N6-methyladenosine (m⁶A) is the most common post-transcriptional mRNA modification and is dynamically regulated by m⁶A regulators. A few studies have shown that the abnormal expression of m⁶A regulators is significantly associated with cancer progression and immune cell infiltration, but the roles of these regulators in PCa remain unclear. Here, we examined the expression profiles and methylation levels of 21 m⁶A regulators across the Cancer Genome Atlas (TCGA), 495 PCas by consensus clustering, and correlated the expression of m⁶A regulators with PCa progression and immune cell infiltration. Consensus clustering was applied for subtyping Pca samples into clusters based on the expression profiles of m⁶A regulators. Each subtype’s signature genes were obtained by a pairwise differential expression analysis. Featured pathways of m⁶A subtypes were predicted by Gene Ontology. The m⁶A score was developed to predict m⁶A activation. The association of the m⁶A score with patients’ survival, metastasis and immune cell infiltration was also investigated. We identified three distinct clusters in PCa based on the expression profiles of 21 m⁶A regulators by consensus clustering. The differential expression and pathway analyses on the three clusters uncovered the m⁶A regulators involved in metabolic processes and immune responses in PCa. Moreover, we developed an m⁶A score to evaluate the m⁶A regulator activation for PCa. The m⁶A score is significantly associated with Gleason scores and metastasis in PCa. The predictive capacity of the m⁶A score on PCa metastasis was also validated in another independent cohort with an area under the curve of 89.5%. Hence, our study revealed the critical role of m⁶A regulators in PCa progression and the m⁶A score is a promising predictive biomarker for PCa metastasis.

Role of m6A writers, erasers and readers in cancer

The N(6)-methyladenosine (m6A) modification is the most pervasive modification of human RNAs. In recent years, an increasing number of studies have suggested that m6A likely plays important roles in cancers. Many studies have demonstrated that m6A is involved in the biological functions of cancer cells, such as proliferation, invasion, metastasis, and drug resistance. In addition, m6A is closely related to the prognosis of cancer patients. In this review, we highlight recent advances in understanding the function of m6A in various cancers. We emphasize the importance of m6A to cancer progression and look forward to describe future research directions.

mRNA N6 -methyladenosine is critical for cold tolerance in Arabidopsis

Plants respond to low temperatures by altering the mRNA abundance of thousands of genes contributing to numerous physiological and metabolic processes that allow them to adapt. At the post-transcriptional level, these cold stress-responsive transcripts undergo alternative splicing, microRNA-mediated regulation and alternative polyadenylation, amongst others. Recently, m⁶ A, m⁵ C and other mRNA modifications that can affect the regulation and stability of RNA were discovered, thus revealing another layer of post-transcriptional regulation that plays an important role in modulating gene expression. The importance of m⁶ A in plant growth and development has been appreciated, although its significance under stress conditions is still underexplored. To assess the role of m⁶ A modifications during cold stress responses, methylated RNA immunoprecipitation sequencing was performed in Arabidopsis seedlings esposed to low temperature stress (4°C) for 24 h. This transcriptome-wide m⁶ A analysis revealed large-scale shifts in this modification in response to low temperature stress. Because m⁶ A is known to affect transcript stability/degradation and translation, we investigated these possibilities. Interestingly, we found that cold-enriched m⁶ A-containing transcripts demonstrated the largest increases in transcript abundance coupled with increased ribosome occupancy under cold stress. The significance of the m⁶ A epitranscriptome on plant cold tolerance was further assessed using the mta mutant in which the major m⁶ A methyltransferase gene was mutated. Compared to the wild-type, along with the differences in CBFs and COR gene expression levels, the mta mutant exhibited hypersensitivity to cold treatment as determined by primary root growth, biomass, and reactive oxygen species accumulation. Furthermore, and most importantly, both non-acclimated and cold-acclimated mta mutant demonstrated hypersensitivity to freezing tolerance. Taken together, these findings suggest a critical role for the epitranscriptome in cold tolerance of Arabidopsis.

Multifaceted Roles of the N6-Methyladenosine RNA Methyltransferase METTL3 in Cancer and Immune Microenvironment

As the most abundant internal mRNA modification in eukaryotic cells, N⁶-methyladenosine (m⁶A) has emerged as an important regulator of gene expression and has a profound impact on cancer initiation and progression. mRNA m⁶A modification is regulated by m⁶A methyltransferases, demethylases and reader proteins to fine tune gene expression at the post-transcriptional level. The most well-studied m⁶A methyltransferase, METTL3, plays critical roles in regulating gene expression and affecting the outcome of various cancers. In this review, we discuss the multifaceted roles of METTL3 in regulating specific molecular signaling pathways in different types of cancers and the recent progress on how METTL3 impacts the tumor immune microenvironment. Finally, we discuss future directions and the potential for therapeutic targeting of METTL3 in cancer treatment.

Construction of a Comprehensive Diagnostic Scoring Model for Prostate Cancer Based on a Novel Six-Gene Panel

Accumulating evidence indicates that the N6-methyladenosine (m⁶A) modification plays a critical role in human cancers. Given the current understanding of m⁶A modification, this process is believed to be dynamically regulated by m⁶A regulators. Although the discovery of m⁶A regulators has greatly enhanced our understanding of the mechanism underlying m⁶A modification in cancers, the function and role of m⁶A in the context of prostate cancer (PCa) remain unclear. Here, we aimed to establish a comprehensive diagnostic scoring model that can act as a complement to prostate-specific antigen (PSA) screening. To achieve this, we first drew the landscape of m⁶A regulators and constructed a LASSO-Cox model using three risk genes (METTL14, HNRNP2AB1, and YTHDF2). Particularly, METTL14 expression was found to be significantly related to overall survival, tumor T stage, relapse rate, and tumor microenvironment of PCa patients, showing that it has important prognostic value. Furthermore, for the sake of improving the predictive ability, we presented a comprehensive diagnostic scoring model based on a novel 6-gene panel by combining with genes found in our previous study, and its application potential was further validated by the whole TCGA and ICGC cohorts. Our study provides additional clues and insights regarding the treatment and diagnosis of PCa patients.

The Potential Role of m6A RNA Methylation in the Aging Process and Aging-Associated Diseases

N6-methyladenosine (m⁶A) is the most common and conserved internal eukaryotic mRNA modification. m⁶A modification is a dynamic and reversible post-transcriptional regulatory modification, initiated by methylase and removed by RNA demethylase. m⁶A-binding proteins recognise the m⁶A modification to regulate gene expression. Recent studies have shown that altered m⁶A levels and abnormal regulator expression are crucial in the ageing process and the occurrence of age-related diseases. In this review, we summarise some key findings in the field of m⁶A modification in the ageing process and age-related diseases, including cell senescence, autophagy, inflammation, oxidative stress, DNA damage, tumours, neurodegenerative diseases, diabetes, and cardiovascular diseases (CVDs). We focused on the biological function and potential molecular mechanisms of m⁶A RNA methylation in ageing and age-related disease progression. We believe that m⁶A modification may provide a new target for anti-ageing therapies.

Role of main RNA modifications in cancer: N6-methyladenosine, 5-methylcytosine, and pseudouridine

Cancer is one of the major diseases threatening human life and health worldwide. Epigenetic modification refers to heritable changes in the genetic material without any changes in the nucleic acid sequence and results in heritable phenotypic changes. Epigenetic modifications regulate many biological processes, such as growth, aging, and various diseases, including cancer. With the advancement of next-generation sequencing technology, the role of RNA modifications in cancer progression has become increasingly prominent and is a hot spot in scientific research. This review studied several common RNA modifications, such as N⁶-methyladenosine, 5-methylcytosine, and pseudouridine. The deposition and roles of these modifications in coding and noncoding RNAs are summarized in detail. Based on the RNA modification background, this review summarized the expression, function, and underlying molecular mechanism of these modifications and their regulators in cancer and further discussed the role of some existing small-molecule inhibitors. More in-depth studies on RNA modification and cancer are needed to broaden the understanding of epigenetics and cancer diagnosis, treatment, and prognosis.

The "m6A writer" METTL3 and the "m6A reader" IGF2BP2 regulate cutaneous T-cell lymphomas (CTCL) progression via CDKN2A

It has been established that Cutaneous T-Cell lymphomas (CTCL) are caused by the monoclonal proliferation of T lymphocytes in the skin. This heterogeneous group of diseases represents a significant source of distress to patients since the diagnosis and treatment are often challenging. As one of the most abundant internal modifications in mRNA in higher eukaryotes, N6-methyladenosine (m6A) is widely recognized to affect the development and progression of cancers. However, knowledge on the involvement of m6A in CTCL is still limited. In this work, we revealed the role of METTL3-mediated m6A modification in CTCL progression. ELISA, western blot, and qRT-PCR assays demonstrated that METTL3 was significantly downregulated in CTCL cells both in vivo and in vitro. CCK-8, EdU, flow cytometry, and transwell assays showed that the decline in METTL3 levels was responsible for CTCL cell proliferation and migration. Furthermore, using small interfering RNAs (siRNAs) against METTL3 and the RIP assay, we showed that CDKN2A was a key regulator during this process in vitro and in vivo, and insufficient methylation modification blocked the interaction between CDKN2A and m6A reader IGF2BP2, resulting in mRNA degradation. To the best of our knowledge, this is the first study to depict the role of m6A in CTCL development and provide potential bio-targets for therapy. This article is protected by copyright. All rights reserved.

METTL3 promotes prostate cancer progression by regulating miR-182 maturation in m6A-dependent manner

METTL3 was known to run through the whole cycle of RNA. It relied on m6A modification in the mRNAs of cancer-related genes to regulate tumour progression. The development of prostate cancer cells could be promoted by METTL3 via hedgehog pathway. Recent studies had shown that the effect of METTL3 on non-coding RNA was mainly dependent on the modification of m6A. However, it is still unknown whether METTL3 promotes tumour development through this mechanism in prostate cancer. The expression of METTL3 in prostate cancer tissues and cells was analysed by qRT-PCR and Western blot assays. CCK-8 assay, colony formation assay, wound-healing assay and transwell assays were conducted to detect the impact of METTL3 on cell proliferation, migration and invasion. Nude mice tumour models were built to evaluate the role of METTL3 in tumorigenesis. N6-methyladenosine (m6A) RNA immunoprecipitation assay (MeRIP) and co-immunoprecipitations assays were performed to verified that METTL3 upregulated the m6A level, interacted with microprocessor protein DGCR8, recognized the m6A modification of pre-miR-182 to regulate its maturation.METTL3 was highly expressed in prostate cancer, and knockdown of METTL3 significantly inhibited cell proliferation, migration, invasion and tumorigenesis, while overexpression of METTL3 promoted cell proliferation, migration, invasion and tumorigenesis in PCa. In addition, we found that METTL3 upregulating the level of m6A, and interacted with DGCR8 to recognize the m6A modification of pre-miR-182 to regulate its splicing and maturation and promote the high expression of miRNA. Our study suggests that METTL3 could be used in targeted therapies for PCa.

A m6Avalue predictive of prostate cancer stemness, tumor immune landscape and immunotherapy response

The molecular mechanisms underpinning prostate cancer (PCa) progression are incompletely understood, and precise stratification of aggressive primary PCa (pri-PCa) from indolent ones poses a major clinical challenge. Here, we comprehensively dissect, genomically and transcriptomically, the m⁶A (N ⁶-methyladenosine) pathway as a whole in PCa. Expression, but not the genomic alteration, repertoire of the full set of 24 m⁶A regulators at the population level successfully stratifies pri-PCa into three m⁶A clusters with distinct molecular and clinical features. These three m⁶A modification patterns closely correlate with androgen receptor signaling, stemness, proliferation and tumor immunogenicity of cancer cells, and stroma activity and immune landscape of tumor microenvironment (TME). We observe a discrepancy between a potentially higher neoantigen production and a deficiency in antigen presentation processes in aggressive PCa, offering insights into the failure of immunotherapy. Identification of PCa-specific m⁶A phenotype-associated genes provides a basis for construction of m⁶Avalue to measure m⁶A methylation patterns in individual patients. Tumors with lower m⁶Avalue are relatively indolent with abundant immune cell infiltration and stroma activity. Interestingly, m⁶Avalue separates PCa TME into fibrotic and nonfibrotic phenotypes (instead of previously reported immune-proficient or -desert phenotypes in other cancer types). Significantly, m⁶Avalue can be used to predict drug response and clinical immunotherapy efficacy in both castration-resistant PCa and other cancer types. Therefore, our study establishes m⁶A methylation modification pattern as a determinant in PCa progression via impacting cancer cell aggressiveness and TME remodeling.

Roles of RNA Modifications in Diverse Cellular Functions

Chemical modifications of RNA molecules regulate both RNA metabolism and fate. The deposition and function of these modifications are mediated by the actions of writer, reader, and eraser proteins. At the cellular level, RNA modifications regulate several cellular processes including cell death, proliferation, senescence, differentiation, migration, metabolism, autophagy, the DNA damage response, and liquid-liquid phase separation. Emerging evidence demonstrates that RNA modifications play active roles in the physiology and etiology of multiple diseases due to their pervasive roles in cellular functions. Here, we will summarize recent advances in the regulatory and functional role of RNA modifications in these cellular functions, emphasizing the context-specific roles of RNA modifications in mammalian systems. As m⁶A is the best studied RNA modification in biological processes, this review will summarize the emerging advances on the diverse roles of m⁶A in cellular functions. In addition, we will also provide an overview for the cellular functions of other RNA modifications, including m⁵C and m¹A. Furthermore, we will also discuss the roles of RNA modifications within the context of disease etiologies and highlight recent advances in the development of therapeutics that target RNA modifications. Elucidating these context-specific functions will increase our understanding of how these modifications become dysregulated during disease pathogenesis and may provide new opportunities for improving disease prevention and therapy by targeting these pathways.

Epigenetic and Epitranscriptomic Control in Prostate Cancer

The initiation of prostate cancer has been long associated with DNA copy-number alterations, the loss of specific chromosomal regions and gene fusions, and driver mutations, especially those of the Androgen Receptor. Non-mutational events, particularly DNA and RNA epigenetic dysregulation, are emerging as key players in tumorigenesis. In this review we summarize the molecular changes linked to epigenetic and epitranscriptomic dysregulation in prostate cancer and the role that alterations to DNA and RNA modifications play in the initiation and progression of prostate cancer.

m6A modification: recent advances, anticancer targeted drug discovery and beyond

Abnormal N6-methyladenosine (m6A) modification is closely associated with the occurrence, development, progression and prognosis of cancer, and aberrant m6A regulators have been identified as novel anticancer drug targets. Both traditional medicine-related approaches and modern drug discovery platforms have been used in an attempt to develop m6A-targeted drugs. Here, we provide an update of the latest findings on m6A modification and the critical roles of m6A modification in cancer progression, and we summarize rational sources for the discovery of m6A-targeted anticancer agents from traditional medicines and computer-based chemosynthetic compounds. This review highlights the potential agents targeting m6A modification for cancer treatment and proposes the advantage of artificial intelligence (AI) in the discovery of m6A-targeting anticancer drugs.

Graphical abstract

Three stages of m6A-targeting anticancer drug discovery: traditional medicine-based natural products, modern chemical modification or synthesis, and artificial intelligence (AI)-assisted approaches for the future.

The role of m6A RNA methylation in cancer metabolism

Metabolic reprogramming is one of the main characteristics of malignant tumors, which is due to the flexible changes of cell metabolism that can meet the needs of cell growth and maintain the homeostasis of tissue environments. Cancer cells can obtain metabolic adaptation through a variety of endogenous and exogenous signaling pathways, which can not only promote the growth of malignant cancer cells, but also start the transformation process of cells to adapt to tumor microenvironment. Studies show that m6A RNA methylation is widely involved in the metabolic recombination of tumor cells. In eukaryotes, m6A methylation is the most abundant modification in mRNA, which is involved in almost all the RNA cycle stages, including regulation the transcription, maturation, translation, degradation and stability of mRNA. M6A RNA methylation can be involved in the regulation of physiological and pathological processes, including cancer. In this review, we discuss the role of m6A RNA methylation modification plays in tumor metabolism-related molecules and pathways, aiming to show the importance of targeting m6A in regulating tumor metabolism.

Four m6A RNA Methylation Gene Signatures and Their Prognostic Values in Lung Adenocarcinoma

Introduction: Evidence demonstrates that N6-methyladenosine (m6A) modification plays an increasingly important role in the development of tumors. The aim of this study is to explore the expression of m6A-related regulators in lung adenocarcinoma, identify the effect of altered key factors modified by m6A on the prognosis of patients with lung adenocarcinoma. Methods: A comprehensive analysis of m6A-related gene expressions in patients with lung adenocarcinoma based on The Cancer Genome Atlas database (TCGA) and the CBioPortal database. A prognostic risk score was established based on a linear combination of 4 key gene expression levels using the regression coefficients of the multivariate Cox regression models. Immunohistochemical staining analysis was performed to validate the relationship between the protein expression level of m6A regulators and the prognosis of patients retrospectively. The possible mechanism and prospective therapeutic targets of these key m6A molecules were explored by the M6A2Target database and the CMAP database. Results: Mutation pattern analysis revealed that 32% of 656 patients had genetic alterations. Four genes (writer: methyltransferase like 3 [METTL3] and three readers: insulin like growth factor 2 mRNA binding protein 2 [IGF2BP2], heterogeneous nuclear ribonucleoprotein C [HNRNPC], and heterogeneous nuclear ribonucleoprotein A2/B1 [HNRNPA2B1]) were selected to construct a survival risk prediction model and the results of immunohistochemical staining showed that the expression of these four m6A genes was significantly different between lung adenocarcinoma tissues and normal lung tissues (p < .01). The possible downstream genes and prospective therapeutic targets of these four m6A key molecules were discovered. Conclusion: These four m6A RNA methylation regulators may be effective prognostic and diagnostic factors which can provide auxiliary diagnosis and prognosis of lung adenocarcinoma.

RNA m6A Methylation Regulators Multi-Omics Analysis in Prostate Cancer

RNA N6-methyladenosine (m6A) methylation is known to be the most popular RNA modification in animals. Many research reports have elaborated on the effects of m6A regulators in medical practice, such as diagnosis, prognosis, and treatment. M6A modification has evident impacts on many aspects of RNA metabolism, just like RNA splicing, processing, translation, and stability. M6A also has a magnificent role in numerous types of cancers. We analyzed the prostate cancer datasets, from The Cancer Genome Atlas (TCGA) database, for every recognized m6A regulator in their gene expression, DNA methylation status and copy number variations (CNVs). We also systematically analyzed the relationship between different m6A regulators and the prognosis of prostate cancer. The results illustrated considerable differences in the expression of various m6A regulators between the prostate and normal cancer samples. At the same time, there were evident differences in the expression of various m6A regulators in prostate cancers with different Gleason scores. Subsequently, we determined CBLL1, FTO, YTHDC1, HNRNPA2B1 as crucial m6A regulators of prostate cancer. Premised on the expression of CBLL1, we also identified potential therapeutic agents for prostate cancer, and knockdown of FTO prominently inhibited prostate cells migration and invasion in vitro experiment.

Increased METTL3-mediated m6A methylation inhibits embryo implantation by repressing HOXA10 expression in recurrent implantation failure

BACKGROUND

Recurrent implantation failure (RIF) is a major limitation of assisted reproductive technology, which is associated with impaired endometrial receptivity. Although N⁶-methyladenosine (m⁶A) has been demonstrated to be involved in various biological processes, its potential role in the endometrium of women with RIF has been poorly studied.

METHODS

Global m⁶A levels and major m⁶A methyltransferases/demethylases mRNA levels in mid-secretory endometrium from normal and RIF women were examined by colorimetric m⁶A quantification strategy and quantitative real-time PCR, respectively. The effects of METTL3-mediated m⁶A modification on embryo attachment were evaluated by an vitro model of a confluent monolayer of Ishikawa cells co-cultured with BeWo spheroids, and the expression levels of homeo box A10 (HOXA10, a well-characterized marker of endometrial receptivity) and its downstream targets were evaluated by quantitative real-time PCR and Western blotting in METTL3-overexpressing Ishikawa cells. The molecular mechanism for METTL3 regulating HOXA10 expression was determined by methylated RNA immunoprecipitation assay and transcription inhibition assay.

RESULTS

Global m⁶A methylation and METTL3 expression were significantly increased in the endometrial tissues from women with RIF compared with the controls. Overexpression of METTL3 in Ishikawa cells significantly decreased the ration of BeWo spheroid attachment, and inhibited HOXA10 expression with downstream decreased β3-integrin and increased empty spiracles homeobox 2 expression. METTL3 catalyzed the m⁶A methylation of HOXA10 mRNA and contributed to its decay with shortened half-life. Enforced expression of HOXA10 in Ishikawa cells effectively rescued the impairment of METTL3 on the embryo attachment in vitro.

CONCLUSION

Increased METTL3-mediated m⁶A modification represents an adverse impact on embryo implantation by inhibiting HOXA10 expression, contributing to the pathogenesis of RIF.