The Role of N6-Methyladenosine (m6A) Methylation Modifications in Hematological Malignancies

Targeting key RNA methylation enzymes to improve the outcome of colorectal cancer chemotherapy (Review)

RNA methylation modifications are closely linked to tumor development, migration, invasion and responses to various therapies. Recent studies have shown notable advancements regarding the roles of RNA methylation in tumor immunotherapy, the tumor microenvironment and metabolic reprogramming. However, research on the association between tumor chemoresistance and N6‑methyladenosine (m6A) methyltransferases in specific cancer types is still scarce. Colorectal cancer (CRC) is among the most common gastrointestinal cancers worldwide. Conventional chemotherapy remains the predominant treatment modality for CRC and chemotherapy resistance is the primary cause of treatment failure. The expression levels of m6A methyltransferases, including methyltransferase‑like 3 (METTL3), METTL14 and METTL16, in CRC tissue samples are associated with patients' clinical outcomes and chemotherapy efficacy. Natural pharmaceutical ingredients, such as quercetin, have the potential to act as METTL3 inhibitors to combat chemotherapy resistance in patients with CRC. The present review discussed the various roles of different types of key RNA methylation enzymes in the development of CRC, focusing on the mechanisms associated with chemotherapy resistance. The progress in the development of certain inhibitors is also listed. The potential of using natural remedies to develop antitumor medications that target m6A methylation is also outlined.

m6A methylation modification and immune cell infiltration: implications for targeting the catalytic subunit m6A-METTL complex in gastrointestinal cancer immunotherapy

N6-methyladenosine (m6A) methylation modification is a ubiquitous RNA modification involved in the regulation of various cellular processes, including regulation of RNA stability, metabolism, splicing and translation. Gastrointestinal (GI) cancers are some of the world's most common and fatal cancers. Emerging evidence has shown that m6A modification is dynamically regulated by a complex network of enzymes and that the catalytic subunit m6A-METTL complex (MAC)-METTL3/14, a core component of m6A methyltransferases, participates in the development and progression of GI cancers. Furthermore, it has been shown that METTL3/14 modulates immune cell infiltration in an m6A-dependent manner in TIME (Tumor immune microenvironment), thereby altering the response of cancer cells to ICIs (Immune checkpoint inhibitors). Immunotherapy has emerged as a promising approach for treating GI cancers. Moreover, targeting the expression of METTL3/14 and its downstream genes may improve patient response to immunotherapy. Therefore, understanding the role of MAC in the pathogenesis of GI cancers and its impact on immune cell infiltration may provide new insights into the development of effective therapeutic strategies for GI cancers.

The significance of autologous hematopoietic stem cell transplantation on immunoglobulin reconstitution and prognosis in elderly patients with multiple myeloma

OBJECTIVES

Autologous hematopoietic stem cell transplantation (ASCT) is a crucial method used in patients with multiple myeloma (MM). This study aims to evaluate the role of ASCT in immunoglobulin (Ig) reconstitution and long-term outcomes in patients aged ≥ 60 years.

METHODS

From March 2008 to May 2019, 93 patients aged ≥ 60 years who were diagnosed with MM and underwent ASCT were retrospectively analyzed. All patients underwent follow-ups and the deadline for follow-up was October 31, 2022. The Ig levels were measured using the immune turbidimetry method at 3, 6, and 12 months after transplantation. Patients who died or experienced relapse were excluded from the analysis. The prognostic value of Ig levels was estimated using the Kaplan-Meier survival curve and Cox regression method.

RESULTS

No patients died, and all patients with complications showed improvements after treatment. Patients in the Ig reconstitution group had a lower international staging system (ISS) stage, whereas those in the immunoparesis group had a higher ISS stage. The median duration of follow-up was 36 (range, 13-120) months. The Ig reconstitution within 12 months indicated a longer overall survival and progression-free survival outcomes. The detection of Ig levels was an independent indicator for the prognosis of MM.

DISCUSSION AND CONCLUSION

The Ig reconstitution within 12 months of ASCT could predict the overall outcomes of patients with MM aged ≥ 60 years.

Exosome miRNAs profiling in serum and prognostic evaluation in patients with multiple myeloma

MicroRNAs (MiRNAs) carried by exosomes play pivotal roles in the crosstalk between cell components in the tumor microenvironment. Our study aimed at identifying the expression profile of exosomal miRNAs (exo-miRNAs) in the serum of multiple myeloma (MM) patients and investigating the regulation networks and their potential functions by integrated bioinformatics analysis. Exosomes in serum from 19 newly diagnosed MM patients and 9 healthy donors were isolated and the miRNA profile was investigated by small RNA sequencing. Differential expression of exo-miRNAs was calculated and target genes of miRNAs were predicted. CytoHubba was applied to identify the hub miRNAs and core target genes. The LASSO Cox regression model was used to develop the prognostic model, and the ESTIMATE immune score was calculated to investigate the correlation between the model and immune status in MM patients. The top six hub differentially expressed serum exo-miRNAs were identified. 513 target genes of the six hub exo-miRNAs were confirmed to be differentially expressed in MM cells in the Zhan Myeloma microarray dataset. Functional enrichment analysis indicated that these target genes were mainly involved in mRNA splicing, cellular response to stress, and deubiquitination. 13 core exo-miRNA target genes were applied to create a novel prognostic signature to provide risk stratification for MM patients, which is associated with the immune microenvironment of MM patients. Our study comprehensively investigated the exo-miRNA profiles in MM patients. A novel prognostic signature was constructed to facilitate the risk stratification of MM patients with distinct outcomes.

Metformin attenuates multiple myeloma cell proliferation and encourages apoptosis by suppressing METTL3-mediated m6A methylation of THRAP3, RBM25, and USP4

Based on the results of epidemiological and preclinical studies, metformin can improve the prognosis of patients with malignant tumors. Studies have confirmed that metformin inhibits multiple myeloma (MM) cell proliferation and promotes apoptosis. Nevertheless, the specific mechanism remains to be elucidated. MM cells were intervened with different doses of metformin to detect cell proliferation and apoptosis. Western blotting and RT-qPCR were employed to assess the expression of METTL3, METTL14, WTAP, FTO, and ALKBH5 after metformin intervention. The microarray dataset GSE29023 was retrieved from the Gene Expression Omnibus (GEO) database and calculated using the R language (limma package) to authenticate differentially expressed genes (DEGs). The database for annotation, visualization, and integrated discovery (David) was applied for GO annotation analysis of DEGs. Subsequently, the string database and Cytoscape software were applied to construct protein-protein interaction (PPI) and DEM hub gene networks. Bioinformatics analysis and MeRIP were applied to predict and test METTL3-mediated m6A levels on mRNA of THRAP3, RBM25, and USP4 in METTL3 knocked-down cells. Then rescue experiments were performed to explore effects of METTL3 and THRAP3, RBM25, or USP4 on cell proliferation and apoptosis. The effect on MM cell xenograft tumor growth was observed by injection of metformin or/and overexpression of METTL3 in in vivo experiments. Metformin decreased cell proliferation and encouraged cell apoptosis in a dose-dependent manner. Global m6A modification was elevated in MM cells compared to normal cells, which was counteracted by metformin treatment. Furthermore, THRAP3, RBM25, and USP4 were identified as possible candidate genes for metformin treatment by GSE29023 data mining. METTL3 interference impaired m6A modification on mRNA of THRAP3, RBM25, and USP4 as well as expression levels. The mRNA stability and expression of THRAP3, RBM25, and USP4 was decreased after metformin treatment, which was reversed by METTL3 overexpression. THRAP3, RBM25 or USP4 knockdown reversed the assistance of METTL3 overexpression on the malignant behavior of MM cells. Finally, upregulation of METTL3 was shown to exert facilitative effects on xenograft tumor growth by blocking metformin injection. The present study demonstrates that metformin can repress the expression of THRAP3, RBM25, and USP4 by inhibiting METTL3-mediated m6A modification, which in turn hamper cell proliferation and promotes cell apoptosis.Abbreviations: multiple myeloma (MM), Gene Expression Omnibus (GEO), differentially expressed genes (DEGs), database for annotation, visualization and integrated discovery (David), protein-protein interaction (PPI), epithelial‑mesenchymal transition (EMT), methyltransferase like 3 (METTL3), methyltransferase like 14 (METTL14), wilms tumor 1-associated protein (WTAP), methyltransferase like 16 (METTL16), acute myeloid leukemia (AML), non-small lung cancer (NSCLC), glioma stem cells (GSCs), normal bone marrow-derived plasma cells (nPCs), false discovery rate (FDR), biological process (BP), optical density (OD), horseradish peroxidase (HRP), M6A RNA immunoprecipitation assay (MeRIP).

Effect of N6-methyladenosine methylation-related gene signature for predicting the prognosis of hepatocellular carcinoma patients

Background and aims

Hepatocellular carcinoma (HCC) is a common cause of cancer-related death in humans. Increasing evidence indicates that an imbalance in N6-methyladenosine (m6A) methylation is linked to the occurrence and development of cancer. We then developed a prognostic model as an independent risk factor with which predict the prognosis of HCC.

Methods

We obtained the gene expression and clinical data of HCC patients from the TCGA databases. The prognostic value of m6A methylation-related genes in patients who had HCC were subjected to comprehensive bioinformatics analysis. We use Risk Score = ∑ i = 1 n Coe f i × X i to construct the risk scoring formula. We collected pathological specimens from 68 patients who had HCC, and conducted immunohistochemical staining experiments on the specimens.

Results

There was a significant correlation between candidate m6A methylation-related genes (YTHDF2, METTL14 and ZC3H13) overall survival of HCC patients. Among the 68 HCC patient specimens that underwent immunohistochemical staining, all cancer tissues were positive for METTL14, YTHDF2, and ZC3H13 staining in contrast to the adjacent tissues. We conducted a Kaplan-Meier survival analysis. The results showed that patients who had low METTL14 expression had a longer survival time than those of patients who had high METTL14 expression. Also, patients with low YTHDF2 expression had a longer survival time than patients with high YTHDF2 expression. Finally, patients with high ZC3H13 expression lived longer than those with low ZC3H13 expression. This result is consistent with the bioinformatics analysis conclusion above.

Conclusions

Generally, the prognostic model that was based on m6A methylation-related genes in this study can effectively predict the prognosis of HCC patients.

RNA Modifications Meet Tumors

RNA modifications occur through the whole process of gene expression regulation, including transcription, translation, and post-translational processes. They are closely associated with gene expression, RNA stability, and cell cycle. RNA modifications in tumor cells play a vital role in tumor development and metastasis, changes in the tumor microenvironment, drug resistance in tumors, construction of tumor cell-cell "internet", etc. Several types of RNA modifications have been identified to date and have various effects on the biological characteristics of different tumors. In this review, we discussed the function of RNA modifications, including N 6-methyladenine (m6A), 5-methylcytosine (m5C), N 7-methyladenosine (m7G), N 1-methyladenosine (m1A), pseudouridine (Ψ), and adenosine-to-inosine (A-to-I), in the microenvironment and therapy of solid and liquid tumors.

Mechanisms of carcinogenic activity triggered by lysine-specific demethylase 1A

Epigenetics has emerged as a prime focus area in the field of cancer research. Lysine-specific demethylase 1A (LSD1), the first discovered histone demethylase, is mainly responsible for catalysing demethylation of histone 3 lysine 4 (H3K4) and H3K9 to activate or inhibit gene transcription. LSD1 is abnormally expressed in various cancers and participates in cancer proliferation, apoptosis, metastasis, invasion, drug resistance and other processes by interacting with regulatory factors. Therefore, it may serve as a potential therapeutic target for cancer. This review summarises the major oncogenic mechanisms mediated by LSD1 and provides a reference for developing novel and efficient anticancer strategies targeting LSD1.

Potential Correlation Between Eczema and Hematological Malignancies Risk: A Systematic Review and Meta-Analysis

Background

Eczema characterized by itch, sleeplessness, and adverse effects on quality of life is associated with a risk of hematological malignancies. However, there is a controversy pertaining to whether this association implies a greater or lesser risk of hematological cancers. We aimed to explore the link between eczema and hematological malignancies risk.

Methods

We systematically searched PubMed and Embase databases from their inception to February 17, 2022. Two reviewers independently screened articles, extracted data and assessed study quality, respectively. The odds ratios and 95% confidence intervals (CIs) were pooled by using fixed or random-effects models.

Results

29 studies involving 2,521,574 participants examined the contribution of eczema to hematological malignancies. We found that eczema significantly increased the risk of Hodgkin's lymphoma (1.44; 95% CI, 1.07–1.95), myeloma (1.15; 95% CI, 1.04–1.28), and significantly decreased the risk of lymphocytic leukemia (0.91; 95% CI, 0.84–0.99); however, it is not significantly associated with Non-Hodgkin's lymphoma, and myelocytic leukemia.

Conclusion

Eczema has been shown to be associated with the risk of hematological cancer, this association still needs to be verified in large randomized controlled trials.

Systematic Review Registration

https://inplasy.com/, INPLASY202260097.

METTL16 promotes hepatocellular carcinoma progression through downregulating RAB11B-AS1 in an m6A-dependent manner

BACKGROUND

The molecular mechanisms driving hepatocellular carcinoma (HCC) remain largely unclear. As one of the major epitranscriptomic modifications, N6-methyladenosine (m6A) plays key roles in HCC. The aim of this study was to investigate the expression, roles, and mechanisms of action of the RNA methyltransferase methyltransferase-like protein 16 (METTL16) in HCC.

METHODS

The expression of METTL16 and RAB11B-AS1 was determined by RT-qPCR. The regulation of RAB11B-AS1 by METTL16 was investigated by RNA immunoprecipitation (RIP), methylated RIP (MeRIP), and RNA stability assays. In vitro and in vivo gain- and loss-of-function assays were performed to investigate the roles of METTL16 and RAB11B-AS1.

RESULTS

METTL16 was upregulated in HCC, and its increased expression was correlated with poor prognosis of HCC patients. METTL16 promoted HCC cellular proliferation, migration, and invasion, repressed HCC cellular apoptosis, and promoted HCC tumoral growth in vivo. METTL16 directly bound long noncoding RNA (lncRNA) RAB11B-AS1, induced m6A modification of RAB11B-AS1, and decreased the stability of RAB11B-AS1 transcript, leading to the downregulation of RAB11B-AS1. Conversely to METTL16, RAB11B-AS1 is downregulated in HCC, and its decreased expression was correlated with poor prognosis of patients with HCC. Furthermore, the expression of RAB11B-AS1 was negatively correlated with METTL16 in HCC tissues. RAB11B-AS1 repressed HCC cellular proliferation, migration, and invasion, promoted HCC cellular apoptosis, and inhibited HCC tumoral growth in vivo. Functional rescue assays revealed that overexpression of RAB11B-AS1 reversed the oncogenic roles of METTL16 in HCC.

CONCLUSIONS

This study identified the METTL16/RAB11B-AS1 regulatory axis in HCC, which represented novel targets for HCC prognosis and treatment.

The Role of N6-Methyladenosine in the Promotion of Hepatoblastoma: A Critical Review

Simple Summary

Hepatoblastoma is the most common malignant pediatric tumor of the liver. Unlike hepatocellular carcinoma (HCC) which has been associated with hepatitis B virus infection or cirrhosis, the etiology of hepatoblastoma remains vague. Genetic syndromes, including familial adenomatous polyposis (FAP), Beckwith-Wiedemann syndrome (BWS), and trisomy 18 syndrome, have been associated with hepatoblastoma. BWS is an overgrowth syndrome which exhibits an alteration of genomic imprinting on chromosome 11p15.5. N⁶-Methyladenosine (M⁶A) is an RNA modification with rampant involvement in the metabolism of cells and malignant diseases. It has been observed to impact the development of various cancers via its governance of gene expression. Here, we explore the role of m⁶A and its genetic associates in promoting HB, and the impact this may have on our future management of the disease.

Abstract

Hepatoblastoma (HB) is a rare primary malignancy of the developing fetal liver. Its course is profoundly influenced by genetics, in the context of sporadic mutation or genetic syndromes. Conventionally, subtypes of HB are histologically determined based on the tissue type that is recapitulated by the tumor and the direction of its differentiation. This classification is being reevaluated based on advances on molecular pathology. The therapeutic approach comprises surgical intervention, chemotherapy (in a neoadjuvant or post-operative capacity), and in some cases, liver transplantation. Although diagnostic modalities and treatment options are evolving, some patients experience complications, including relapse, metastatic spread, and suboptimal response to chemotherapy. As yet, there is no consistent framework with which such outcomes can be predicted. N⁶-methyladenosine (m⁶A) is an RNA modification with rampant involvement in the normal processing of cell metabolism and neoplasia. It has been observed to impact the development of a variety of cancers via its governance of gene expression. M⁶A-associated genes appear prominently in HB. Literature data seem to underscore the role of m⁶A in promotion and clinical course of HB. Illuminating the pathogenetic mechanisms that drive HB are promising additions to the understanding of the clinically aggressive tumor behavior, given its potential to predict disease course and response to therapy. Implicated genes may also act as targets to facilitate the evolving personalized cancer therapy. Here, we explore the role of m⁶A and its genetic associates in the promotion of HB, and the impact this may have on the management of this neoplastic disease.

Transcriptome-Wide Analysis of RNA N6-Methyladenosine Modification in Adriamycin-Resistant Acute Myeloid Leukemia Cells

Acute myeloid leukemia (AML) is one of the most aggressive hematopoietic malignancies. Patients still suffer from refractory/relapsed disease after anthracycline-based therapy, which leads to a poor prognosis. N⁶-Methyladenosine (m⁶A) is the most abundant post-transcriptional modification in eukaryotes, the imbalance of which is reported to be associated with various pathological processes, including drug resistance. However, the relationship between m⁶A modification and drug resistance has not been well defined in AML. In this study, we analyzed the sequencing data of HL60 and its Adriamycin-resistant cell line HL60/ADR. We found a total of 40,550 m⁶A-methylated peaks, representing 15,640 genes in HL60, and 38,834 m⁶A-methylated peaks, representing 15,285 genes in HL60/ADR. KEGG pathway analysis showed that pathways were enriched in the FoxO signaling pathway, p53 signaling pathway, and Notch signaling pathway. MeRIP-seq results showed that the fold enrichment of the global m⁶A level in HL60/ADR was higher than that in HL60, and dot blot assay results indicated that the global m⁶A level was elevated in HL60/ADR cells compared with that in HL60 cells. Further analysis revealed that the expression level of METTL3 was elevated in HL60/ADR cells compared with that in HL60 cells. After a combined treatment of STM2457 (an inhibitor of METTL3) and Adriamycin, the proliferation of HL60/ADR was inhibited. Thus, we hypothesized that the abnormality of m⁶A modification played an important role in Adriamycin-resistant AML.