Non-Coding RNA m6A Modification in Cancer: Mechanisms and Therapeutic Targets

MicroRNAs as biomarkers in brain metastasis

Cancer patients face a particularly daunting obstacle when tumors spread to the brain, a condition that substantially increases mortality rates. Traditional diagnostic tools have proven inadequate, creating an urgent need for less invasive detection methods. Among emerging solutions, noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), have captured researchers' attention. These molecular elements play key roles in determining disease outcomes and treatment response in brain metastases, helping scientists better understand disease mechanisms and identify potential therapeutic interventions. Research has revealed altered patterns of ncRNA expression across various primary cancers that spread to the brain, suggesting new possibilities for treatment and prevention strategies. By examining ncRNA patterns in blood serum and cerebrospinal fluid, clinicians can potentially distinguish brain metastases from primary brain tumors without invasive procedures. The immune response within the brain microenvironment is notably influenced by ncRNAs, with miRNAs playing an especially crucial role. miRNAs show particular promise as diagnostic markers, helping to separate healthy from cancerous tissue and determine the original source of brain metastases. The therapeutic potential of miRNAs is equally significant, as targeting miRNAs could lead to more effective treatments with fewer side effects. Given the current scarcity of treatment options for brain metastases, the use of ncRNAs, especially miRNAs, represents a promising development in both diagnosis and treatment. Additional clinical research is needed to confirm the accuracy and reliability of ncRNA-based approaches, which could revolutionize how healthcare providers address this challenging aspect of cancer care and improve patient outcomes.

The Role of M6A LncRNA Modification in Papillary Thyroid Cancer

Thyroid Cancer (TC) is the most common endocrine cancer, of which papillary thyroid cancer (PTC), a well-differentiated type of TC, accounts for 80-90%. Long non-coding RNAs (lncRNAs), which comprise non-protein-coding segments of the genome, have been found to play a crucial role in various biological processes, including cancer development. The activity of lncRNAs is modified through epigenetic modifications, with N6-Methyladenosine (m6A) modifications implicated in the progression of several malignancies. The activity of m6A is further regulated by modifying enzymes classified as "readers", writers", and "erasers", of which specific enzymes have been found to play a role in various aspects of PTC. Recent research has highlighted the significance of m6A modification in regulating the expression and function of lncRNAs associated with PTC pathogenesis. Dysregulation of this process implicates tumor proliferation, invasion, and metastasis, with subsequent impact on prognosis. Therefore, understanding the interplay between m6A modification and lncRNAs provides valuable insights into the molecular mechanisms underlying PTC progression. This narrative review aims to explore the established role of several prominent m6A modifying enzymes and lncRNAs on cancer pathogenesis and seeks to clarify the function of these enzymes in PTC pathogenesis.

Recent Advances in the Mutual Regulation of m6A Modification and Non-Coding RNAs in Atherosclerosis

Atherosclerosis, a progressive inflammatory disease of the arteries, remains a leading cause of cardiovascular morbidity and mortality worldwide. Recent years have witnessed the pivotal role of N6-methyladenosine (m6A) RNA methylation in regulating various biological processes, including those implicated in atherosclerosis. Current evidence suggested that m6A regulators (writers, erasers, and readers) participated in the modification of multiple non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), thereby affecting their metabolism and functions. Meanwhile, ncRNAs have also emerged as key modulator of m6A regulators expression in turn. Therefore, understanding the mutual regulation between m6A modifications and ncRNAs is of great significance to identify novel therapeutic targets for atherosclerosis and has great clinical application prospects. This review aims to summarize the recent advances in the reciprocal regulation and provide insights into the interaction between m6A modification and ncRNAs in the context of atherosclerosis.

Epigenetic regulation in female reproduction: the impact of m6A on maternal-fetal health

With the development of public health, female diseases have become the focus of current concern. The unique reproductive anatomy of women leads to the development of gynecological diseases gradually become an important part of the socio-economic burden. Epigenetics plays an irreplaceable role in gynecologic diseases. As an important mRNA modification, m6A is involved in the maturation of ovum cells and maternal-fetal microenvironment. At present, researchers have found that m6A is involved in the regulation of gestational diabetes and other reproductive system diseases, but the specific mechanism is not clear. In this manuscript, we summarize the components of m6A, the biological function of m6A, the progression of m6A in the maternal-fetal microenvironment and a variety of gynecological diseases as well as the progression of targeted m6A treatment-related diseases, providing a new perspective for clinical treatment-related diseases.

MRTX1133 attenuates KRASG12D mutated-colorectal cancer progression through activating ferroptosis activity via METTL14/LINC02159/FOXC2 axis

Colorectal cancer (CRC) ranks as the third most commonly diagnosed cancer and the second leading cause of cancer-related deaths worldwide. Studies have shown that CRC patients with KRAS mutations, especially KRASG12D, have an increased risk of metastasis. Emerging evidence indicates that long non-coding RNAs (lncRNAs) are crucial in the carcinogenesis and progression of various cancers, regulating multiple biological processes but the link between KRASG12D mutations and lncRNAs in CRC remains unclear. Therefore, this study was designed to identify a novel lncRNA involved in KRASG12D-mutated CRC and to elucidate its molecular mechanisms. The analysis of differentially expressed lncRNAs in the GSE201412 dataset revealed that LINC02159 was significantly upregulated following treatment with the KRASG12D inhibitor MTRX1133 Data from the GTEx database indicated that LINC02159 is highly expressed in CRC tumour tissues and is associated with better patient outcomes. In vitro and in vivo experiments suggest that LINC02159 acts as a tumour suppressor in CRC progression. Specifically, LINC02159 knockdown negated the inhibitory effects of MRTX1133 on tumourigenesis and its promotive effect on ferroptosis in KRASG12D-mutated CRC cells. LINC02159 expression is regulated by METTL14, with METTL14 knockdown decreasing m6A methylation of LINC02159, leading to its increased expression in CRC cells. Additionally, LINC02159 stabilised FOXC2 expression through de-ubiquitination. Rescue experiments further clarified that the METTL14/LINC02159/FOXC2 signalling axis is crucial for the inhibitory effects of MRTX1133 in KRASG12D-mutated CRC. Our study provides novel insights into the therapeutic potential of MRTX1133 in treating KRASG12D-mutated CRC by identifying a METTL14/LINC02159/FOXC2 signalling axis that mediates drug response. Our findings highlight the importance of understanding the molecular mechanisms of lncRNAs in cancer to develop effective targeted therapies.

Lycorine affects tamoxifen resistance of breast cancer via m6A-based HAGLR

Background

N6-methyladenosine (m6A)-mediated epitranscriptomic pathway has been shown to contribute to chemoresistance and radioresistance. Our previous work confirmed the defense of lycorine against tamoxifen resistance of breast cancer (BC) through targeting HOXD antisense growth-associated long non-coding RNA (HAGLR). Whereas, the precise regulation among them remains to be elucidated. The aim of this study was to investigate the role of IGF2BP2-mediated m6A methylation in the regulation of HAGLR and its impact on lycorine's effect on tamoxifen resistance in BC.

Methods

m6A status was detected via methylated RNA immunoprecipitation-quantitative polymerase chain reaction (MeRIP-qPCR). Relative expression of HAGLR and IGF2BP2 were tested by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analysis, respectively. Cell viability, proliferation and apoptosis were estimated via Cell Counting Kit-8 (CCK-8), colony formation and flow cytometer analysis. Interplay among IGF2BP2 and HAGLR was tested by RNA immunoprecipitation (RIP) assay. IC50 value of BC cells to tamoxifen was determined by 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay.

Results

Total m6A level in tamoxifen-resistant BC cells (TAMR/MCF-7 and TAMR/T47D) was elevated relative to corresponding parental cells and normal mammary epithelial cell line, MCF10A, either with the presence of m6A modifications within HAGLR sequence. Moreover, IGF2BP2-mediated m6A methylation drove the upregulation and stability of HAGLR in TAMR BC cells. IGF2BP2 served as a key downstream target mediating the anti-tumors of lycorine on TAMR BC. Knockdown of IGF2BP2 or HAGLR could reduce the IC50 value of TAMR/MCF-7 and TAMR/T47D cells to tamoxifen.

Conclusions

Our results demonstrated that lycorine inhibits tamoxifen-resistant BC by repressing IGF2BP2-mediated m6A methylation of HAGLR.

METTL3 facilitates the progression of cervical cancer by m6A modification-mediated up-regulation of NEK2

N6-methyladenosine (m6A) is the most prevalent modification found in eukaryotic RNA and played a significant role in various cancers. However, the mechanism by which m6A modification influences cervical cancer (CC) tumorigenesis remains unclear. Therefore, we aim to elucidate the role and mechanism of METTL3 in CC progression. In the present study, we observed a significant upregulation of METTL3 in CC tissues and cell lines. Knockdown of METTL3 resulted in reduced growth, migration, and invasion of CC cells, as well as affected apoptosis, while overexpression of METTL3 reversed these effects. Through a combined analysis of meRIP-seq and Ribo-seq data following METTL3 knockdown, NEK2 was identified as a key target of METTL3 in CC cells. Correlation analysis, MeRIP-qPCR, and luciferase reporter assay suggested that METTL3 regulates NEK2 expression through m6A modification. NEK2 synergized with METTL3 to mediate the malignant phenotype of CC cells. The METTL3-NEK2 axis promoted CC progression by activating the Wnt/β-catenin pathway and inhibiting the apoptosis pathway. In conclusion, METTL3 facilitated the malignant progression of CC and contributed to the formation of the METTL3-NEK2 regulatory axis in an m6A-dependent manner, which represented a potential target for CC therapy.

N6-methyladenosine-modified lncRNA in Staphylococcus aureus-injured bovine mammary epithelial cells

Staphylococcus aureus-induced mastitis is a serious disease in dairy bovine, with no currently effective treatment. Antibiotics demonstrate certain therapeutic potency in dairy husbandry; they generate drug-resistant bacteria, thereby harming public health. LncRNAs and m6A have been verified as potential targets in infectious diseases and have powerful regulatory capabilities. However, the biological regulation of lncRNAs with m6A modification in mastitis needs further investigation. This study aims to determine the m6A-modified lncRNAs in bovine mammary epithelial cells and their diversity during S. aureus induction. Heat-inactivated S. aureus was used to develop the cell injury model, and we subsequently found low cell viability and different m6A modification levels. Our analysis of m6A-modified lncRNA profiles through MeRIP-seq revealed significant differences in 140 peaks within 130 lncRNAs when cells were injured by S. aureus. Furthermore, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that these differential m6A-modified lncRNAs were mainly enriched in the WNT pathway, and their functions were associated with amino acid metabolism, lipid translocation, and metalloproteinase activity. Here, we report for the first time lncRNAs with m6A modification in regulating S. aureus infection, revealing potential mechanisms and targets of infectious diseases, such as mastitis, from an epigenetics perspective.

Characterization of growth arrest-specific transcript 5 and growth arrest-specific transcript 5-related m6A gene signature in glioma: An observational study

Glioma remains a significant clinical challenge and poses a dismal patient prognosis. This study focused on the long noncoding ribonucleic acid growth arrest-specific transcript 5 (GAS5) and explored the role of GAS5 and GAS5-related m6A genes in glioma. We explored the mechanisms of GAS5 expression in glioma using bioinformatic analysis based on glioma data from the Cancer Genome Atlas, GSE1142, and Chinese Glioma Genome Atlas databases. Kaplan-Meier curve analysis, nomogram construction, immune cell infiltration, drug sensitivity, mutations, and pathway analyses were performed to determine the GAS5 mechanism in glioma. Spearman correlation and weighted gene co-expression analyses were used to identify the GAS5-related m6A gene. Furthermore, we explored the correlation between GAS5, GAS5-related m6A gene, and clinical traits using analysis of variance. The Kaplan-Meier curve analysis suggested that patients with high expressions of GAS5 had better survival. The nomogram constructed indicated that GAS5 was an independent prognostic factor. Furthermore, GAS5 significantly correlated with plasma cells. GAS5 expression was significantly associated with biological processes, including oxidative phosphorylation, proteasome, and ribosome mitotic spindle. GAS5 expression was associated with sensitivity to erlotinib and gemcitabine. Differentially expressed GAS5 was significant in histology (P = 2.8e-09), grade (P = 3.7e-05), isocitrate dehydrogenase (IDH) mutation (P = 3.4e-17), 1p/19q co-deletion (Codel) status (P = 1.7e-08), and IDH mutation status and 1p/19q Codel status (P = 2.9e-18). Heterogeneous nuclear ribonucleoproteins C1/C2 (HNRNPC) gene was significant in IDH mutation (P = .008) and IDH mutation status and 1p/19q Codel status (P = 2.1e-05). GAS5 and HNRNPC expressions reflected the malignant grade of glioma and are associated with prognosis. The abnormal expression of GAS5 could be an important biomarker for guiding erlotinib and gemcitabine use in glioma treatment. GAS5 and heterogeneous nuclear ribonucleoproteins C1/C2 are potential diagnostic and prognostic markers for glioma.

α-Ketoglutarate plays an inflammatory inhibitory role by regulating scavenger receptor class a expression through N6-methyladenine methylation during sepsis

Sepsis arises from an uncontrolled inflammatory response triggered by infection or stress, accompanied by alteration in cellular energy metabolism, and a strong correlation exists between these factors. Alpha-ketoglutarate (α-KG), an intermediate product of the TCA cycle, has the potential to modulate the inflammatory response and is considered a crucial link between energy metabolism and inflammation. The scavenger receptor (SR-A5), a significant pattern recognition receptor, assumes a vital function in anti-inflammatory reactions. In the current investigation, we have successfully illustrated the ability of α-KG to mitigate inflammatory factors in the serum of septic mice and ameliorate tissue damage. Additionally, α-KG has been shown to modulate metabolic reprogramming and macrophage polarization. Moreover, our findings indicate that the regulatory influence of α-KG on sepsis is mediated through SR-A5. We also elucidated the mechanism by which α-KG regulates SR-A5 expression and found that α-KG reduced the N6-methyladenosine level of macrophages by up-regulating the m6A demethylase ALKBH5. α-KG plays a crucial role in inhibiting inflammation by regulating SR-A5 expression through m6A demethylation during sepsis. The outcomes of this research provide valuable insights into the relationship between energy metabolism and inflammation regulation, as well as the underlying molecular regulatory mechanism.

Role of RNA modifications in cancer metastasis

The epitranscriptome encompasses over 170 post-transcriptional modifications found in various RNA species. RNA modifications play pivotal roles in regulating gene expression by shaping RNA structure and function, implicating the epitranscriptome in diverse biological processes, including pathology progression. This review focuses on research elucidating the roles of the epitranscriptome in cancer metastasis. Metastasis, a primary cause of solid tumor patient mortality, involves a multistep process whereby tumor cells migrate from a primary tumor to distant secondary organs. We discuss RNA modifications found on rRNA, tRNA, and mRNA, highlighting their roles in different stages of metastasis. Understanding mechanisms by which modifications regulate molecular and cellular processes during metastasis is crucial for leveraging epitranscriptomic signatures in cancer diagnosis and treatment.

Decoding the ribosome's hidden language: rRNA modifications as key players in cancer dynamics and targeted therapies

Ribosomal RNA (rRNA) modifications, essential components of ribosome structure and function, significantly impact cellular proteomics and cancer biology. These chemical modifications transcend structural roles, critically shaping ribosome functionality and influencing cellular protein profiles. In this review, the mechanisms by which rRNA modifications regulate both rRNA functions and broader cellular physiological processes are critically discussed. Importantly, by altering the translational output, rRNA modifications can shift the cellular equilibrium towards oncogenesis, thus playing a key role in cancer development and progression. Moreover, a special focus is placed on the functions of mitochondrial rRNA modifications and their aberrant expression in cancer, an area with profound implications yet largely uncharted. Dysregulation in these modifications can lead to metabolic dysfunction and apoptosis resistance, hallmark traits of cancer cells. Furthermore, the current challenges and future perspectives in targeting rRNA modifications are highlighted as a therapeutic approach for cancer treatment. In conclusion, rRNA modifications represent a frontier in cancer research, offering novel insights and therapeutic possibilities. Understanding and harnessing these modifications can pave the way for breakthroughs in cancer treatment, potentially transforming the approach to combating this complex disease.

HNRNPC promotes estrogen receptor-positive breast cancer cell cycle by stabilizing WDR77 mRNA in an m6A-dependent manner

Breast cancer has become the most commonly diagnosed cancer. Heterogeneous nuclear ribonucleoprotein C (HNRNPC), a reader of N6-methyladenosine (m6A), has been observed to be upregulated in various types of cancer. Nevertheless, the role of HNRNPC in breast cancer and whether it is regulated by m6A modification deserve further investigation. The expression of HNRNPC in breast cancer was examined by quantitative real-time polymerase chain reaction and western blot analysis. RNA immunoprecipitation was performed to validate the binding relationships between HNRNPC and WD repeat domain 77 (WDR77). The effects of HNRNPC and m6A regulators on WDR77 were investigated by actinomycin D assay. The experiments in vivo were conducted in xenograft models. In this research, we found that HNRNPC was highly expressed in breast cancer, and played a crucial role in cell growth, especially in the luminal subtype. HNRNPC could combine and stabilize WDR77 mRNA. WDR77 successively drove the G1/S phase transition in the cell cycle and promoted cell proliferation. Notably, this regulation axis was closely tied to the m6A modification status of WDR77 mRNA. Overall, a critical regulatory mechanism was identified, as well as promising targets for potential treatment strategies for luminal breast cancer.

Analysis of m6A-related lncRNAs for prognostic and immunotherapeutic response in hepatocellular carcinoma

Background: RNA methylation modifications are important post-translational modifications that are regulated in an epigenetic manner. Recently, N6-methyladenosine (m6A) RNA modifications have emerged as potential epigenetic markers in tumor biology. Methods: Gene expression and clinicopathological data of LIHC were obtained from the cancer genome atlas (TCGA) database. The relationship between long non-coding RNAs (lncRNAs) and m6A-related genes was determined by gene expression analysis using Perl and R software. Co-expression network of m6A-lncRNA was constructed, and the relevant lncRNAs associated with prognosis were identified using univariate Cox regression analysis. These lncRNAs were then divided into two clusters (cluster 1 and cluster 2) to determine the differences in survival, pathoclinical parameters, and immune cell infiltration between the different lncRNA subtypes. The least absolute shrinkage and selection operator (LASSO) was carried out for regression analysis and prognostic model. The HCC patients were randomly divided into a train group and a test group. According to the median risk score of the model, HCC patients were divided into high-risk and low-risk groups. We built models using the train group and confirmed them through the test group. The m6A-lncRNAs derived from the models were analyzed for the tumor mutational burden (TMB), immune evasion and immune function using R software. AL355574.1 was identified as an important m6A-associated lncRNA and selected for further investigation. Finally, in vitro experiments were conducted to confirm the effect of AL355574.1 on the biological function of HCC and the possible biological mechanisms. Huh7 and HepG2 cells were transfected with AL355574.1 siRNA and cell proliferation ability was measured by CCK-8, EdU and colony formation assays. Wound healing and transwell assays were used to determine the cell migration capacity. The expression levels of MMP-2, MMP-9, E-cadherin, N-cadherin and Akt/mTOR phosphorylation were all determined by Western blotting. Results: The lncRNAs with significant prognostic value were classified into two subtypes by a consistent clustering analysis. We found that the clinical features, immune cell infiltration and tumor microenvironment (TME) were significantly different between the lncRNA subtypes. Our analysis revealed significant correlations between these different lncRNA subtypes and immune infiltrating and stromal cells. We created the final risk profile using LASSO regression, which notably included three lncRNAs (AL355574.1, AL158166.1, TMCC1-AS1). A prognostic signature consisting of the three lncRNAs was constructed, and the model showed excellent prognostic predictive ability. The overall survival (OS) of the low-risk cohort was significantly higher than that of the high-risk cohort in both the train and test group. Both risk score [hazard ratio (HR)=1.062; P<0.001] and stage (HR=1.647; P< 0.001) were considered independent indicators of HCC prognosis by univariate and multivariate Cox regression analysis. In Huh7 and HepG2 cells, AL355574.1 knockdown inhibited cell proliferation and migration, suppressed the protein expression levels of MMP-2, MMP-9, N-cadherin and Akt/mTOR phosphorylation, but promoted the protein expression levels of E-cadherin. Conclusions: This study established a predictive model for the OS of HCC patients, and these OS-related m6A-lncRNAs, especially AL355574.1 may play a potential role in the progression of HCC. In vitro experiments also showed that AL355574.1 could enhance the expression of MMPs and EMT through the Akt/mTOR signaling pathway, thereby affected the proliferation and migration of HCC. This provides a new perspective on the anticancer molecular mechanism of AL355574.1 in HCC.

Interactions between circRNA and protein in breast cancer

Circular RNA (circRNA) is a newly discovered endogenous non-coding RNA that plays important roles in the occurrence and development of various cancers. Current research indicates that circRNA can inhibit the function of miRNA by acting as an miRNA sponge, interacting with proteins, and being translated into proteins. Most current research focuses on the circRNA-miRNA interaction; however, few studies have investigated the interaction between circRNAs and RNA binding proteins (RBPs) in breast cancer. In this review, we systematically summarize the potential molecular mechanism of the circRNA-protein interaction in breast cancer. Specifically, we elaborate on the direct interaction between circRNAs and proteins in breast cancer, including the functions of circRNA as protein sponges, decoys, and scaffolds, thereby affecting the progression of breast cancer. We also discuss the indirect interaction between circRNAs and proteins in breast cancer in which RBPs, transcription factors and m6A modifying enzymes could in turn regulate the expression and formation of circRNA. Finally, we discuss the potential application of circRNA-protein interaction for treating breast cancer, providing a reference for further research in this field.

YTHDF1's Regulatory Involvement in Breast Cancer Prognosis, Immunity, and the ceRNA Network

YTH N6-methyladenosine RNA binding protein 1 (YTHDF1), an m6A reader, has a role in the development and progression of breast cancer as well as the immunological microenvironment. The networks of competing endogenous RNA in cancer have received much attention in research. In tumor gene therapy, the regulatory networks of m6A and competing endogenous RNA are increasingly emerging as a new route. We evaluated the relationship between the YTHDF1 expression, overall survival, and clinicopathology of breast cancer using TCGA, PrognoScan, and other datasets. We used Western blot to demonstrate that YTHDF1 is substantially expressed in breast cancer tissues. Furthermore, we explored YTHDF1's functions in the tumor mutational burden, microsatellite instability, and tumor microenvironment. Our findings indicate that YTHDF1 is a critical component of the m6A regulatory proteins in breast cancer and may have a particular function in the immunological microenvironment. Crucially, we investigated the relationship between YTHDF1 and the associated competitive endogenous RNA regulatory networks, innovatively creating three such networks (Dehydrogenase/Reductase 4-Antisense RNA 1-miR-378g-YTHDF1, HLA Complex Group 9-miR-378g-YTHDF1, Taurine Up-regulated 1-miR-378g-YTHDF1). Furthermore, we showed that miR-378g could inhibit the expression of YTHDF1, and that miR-378g/YTHDF1 could impact MDA-MB-231 proliferation. We speculate that YTHDF1 may serve as a biomarker for poor prognosis and differential diagnosis, impact the growth of breast cancer cells via the ceRNA network axis, and be a target for immunotherapy against breast cancer.

METTL14/miR-29c-3p axis drives aerobic glycolysis to promote triple-negative breast cancer progression though TRIM9-mediated PKM2 ubiquitination

The energy metabolic rearrangement of triple-negative breast cancer (TNBC) from oxidative phosphorylation to aerobic glycolysis is a significant biological feature and can promote the malignant progression. However, there is little knowledge about the functional mechanisms of methyltransferase-like protein 14 (METTL14) mediated contributes to TNBC malignant progression. Our study found that METTL14 expression was significantly upregulated in TNBC tissues and cell lines. Silencing METTL14 significantly inhibited TNBC cell growth and invasion in vitro, as well as suppressed tumour growth. Mechanically, METTL14 was first found to activate miR-29c-3p through m6A and regulate tripartite motif containing 9 (TRIM9) to promote ubiquitination of pyruvate kinase isoform M2 (PKM2) and lead to its transition from tetramer to dimer, resulting in glucose metabolic reprogramming from oxidative phosphorylation to aerobic glycolysis to promote the progress of TNBC. Taken together, these findings reveal important roles of METTL14 in TNBC tumorigenesis and energy metabolism, which might represent a novel potential therapeutic target for TNBC.

m6A methylation-mediated regulation of LncRNA MEG3 suppresses ovarian cancer progression through miR-885-5p and the VASH1 pathway

BACKGROUND

Ovarian cancer poses a serious threat to women's health. Due to the difficulty of early detection, most patients are diagnosed with advanced-stage disease or peritoneal metastasis. We found that LncRNA MEG3 is a novel tumor suppressor, but its role in tumor occurrence and development is still unclear.

METHODS

We investigated the expression level of MEG3 in pan-cancer through bioinformatics analysis, especially in gynecological tumors. Function assays were used to detect the effect of MEG3 on the malignant phenotype of ovarian cancer. RIP, RNA pull-down, MeRIP-qPCR, actinomycin D test were carried out to explore the m6A methylation-mediated regulation on MEG3. Luciferase reporter gene assay, PCR and Western blot were implemented to reveal the potential mechanism of MEG3. We further confirmed the influence of MEG3 on tumor growth in vivo by orthotopic xenograft models and IHC assay.

RESULTS

In this study, we discovered that MEG3 was downregulated in various cancers, with the most apparent downregulation in ovarian cancer. MEG3 inhibited the proliferation, migration, and invasion of ovarian cancer cells. Overexpression of MEG3 suppressed the degradation of VASH1 by negatively regulating miR-885-5p, inhibiting the ovarian cancer malignant phenotype. Furthermore, we demonstrated that MEG3 was regulated at the posttranscriptional level. YTHDF2 facilitated MEG3 decay by recognizing METTL3‑mediated m6A modification. Compared with those injected with vector control cells, mice injected with MEG3 knockdown cells showed larger tumor volumes and faster growth rates.

CONCLUSION

We demonstrated that MEG3 is influenced by METTL3/YTHDF2 methylation and restrains ovarian cancer proliferation and metastasis by binding miR-885-5p to increase VASH1 expression. MEG3 is expected to become a therapeutic target for ovarian cancer.

An exploration of the effect of Chinese herbal compound on the occurrence and development of large intestine cancer and intestinal flora

This study was conducted to observe the effect of Chinese herbal compound on the treatment of colon cancer using AOM/DSS-induced C57BL/6J colon cancer mice and to validate potential influence on intestinal flora of mice. A colorectal cancer (CRC) mouse model was built with a total of 50 C57BL/6J mice that were induced by administrating AOM/DSS. These experimental animals were split up into 5 groups, a control group, a model group, and low-, medium- and high-dose Chinese herbal compound groups. All mice were given Chinese herbal compound treatment, and the colon tissues of each group were harvested with the length measured and the number of colon polyps accounted. The Ki-67 expression in the colon tissues was detected via immuno-histochemistry. Relative quantification of the expression of genes and proteins was determined through qPCR and WB assays. Contents of IL-6, TNF-α, IFN-γ, and IL-10 in serum and colon tissues of mice were determined by ELISA. An additional 16S rRNA sequencing analysis was implemented for the identification of mouse intestinal flora. The results suggested that all low-, medium- or high-dose Chinese herbal compound could markedly inhibit the shortening of colon length and significant number reduction of colon polyps in the model group. The relative expression of genes and proteins (PCNA, Muc16, and MMP-9) associated with proliferation in mouse colon tissues were inhibited. In addition, compared with the model group, the contents of IL-6, TNF-α, and IFN-γ in serum and colon tissues were substantially decreased in the high-dose Chinese herbal compound group, thereby reducing the structure damage in colon tissues and the infiltration degree of inflammatory cells. Besides, the expression of TLR4/MyD88/NF-κB protein was markedly decreased. The 16S rRNA sequencing analysis demonstrated that mice in the model group had decreased intestinal flora diversity, and there were significant changes in flora abundance and amino acid metabolism between the control group and the model group. Taken together, the treatment of Chinese herbal compound against CRC in this study might be regulated by the TLR4/MyD88/NF-κB signaling pathway, and the imbalance in intestinal flora was also closely related to CRC occurrence.

METTL3 regulates the proliferation, metastasis and EMT progression of bladder cancer through P3H4

Bladder cancer, the most common malignant tumor in the urinary system, exhibits significantly up-regulated expression of P3H4, which is associated with pathological factors. The objective of this study was to elucidate the underlying mechanism of P3H4 in bladder cancer. Initially, we analyzed P3H4 gene expression using the TCGA database and evaluated P3H4 levels in clinical samples and various bladder cell lines. P3H4 was found to be markedly overexpressed in bladder cancer samples. Subsequently, bladder cancer cells were transfected with shRNA targeting P3H4 (sh-P3H4), sh-METTL3, and P3H4 overexpression vectors (P3H4 OE). Viability, migration, and invasion of bladder cancer cells were assessed using CCK-8, wound healing, and transwell assays. Western blot analysis was performed to determine the levels of EMT-associated proteins, while RNA stability assays determined the half-life of P3H4. Knockdown of P3H4 resulted in inhibition of bladder cancer cell proliferation, migration, invasion, and EMT progression. Mechanistically, METTL3 was found to regulate the mRNA stability of P3H4 in bladder cancer. Moreover, overexpression of P3H4 reversed the inhibitory effects of METTL3 knockdown on bladder cancer cell behaviors. Stable cell lines were established by infecting EJ cells with lentiviral vectors containing sh-METTL3 or P3H4 OE. These cells were then implanted into the skin of BALB/c nude mice, and IHC analysis was used to analyze the expression levels of EMT-associated proteins. In vivo studies demonstrated that inhibition of METTL3 suppressed bladder cancer growth and EMT through P3H4. In conclusion, our findings suggest that METTL3 regulates the proliferation, metastasis, and EMT progression of bladder cancer through P3H4, highlighting its potential as a therapeutic target.

m6A modified BACE1-AS contributes to liver metastasis and stemness-like properties in colorectal cancer through TUFT1 dependent activation of Wnt signaling

BACKGROUND

Liver metastasis is one of the most important reasons for high mortality of colorectal cancer (CRC). Growing evidence illustrates that lncRNAs play a critical role in CRC liver metastasis. Here we described a novel function and mechanisms of BACE1-AS promoting CRC liver metastasis.

METHODS

qRT-PCR and in situ hybridization were performed to examine the BACE1-AS level in CRC. IGF2BP2 binding to m6A motifs in BACE1-AS was determined by RIP assay and S1m-tagged immunoprecipitation. Transwell assay and liver metastasis mice model experiments were performed to examine the metastasis capabilities of BACE1-AS knockout cells. Stemness-like properties was examined by tumor sphere assay and the expression of stemness biomarkers. Microarray data were acquired to analyze the signaling pathways involved in BACE1-AS promoting CRC metastasis.

RESULTS

BACE1-AS is the most up-regulated in metastatic CRC associated with unfavorable prognosis. Sequence blast revealed two m6A motifs in BACE1-AS. IGF2BP2 binding to these two m6A motifs is required for BACE1-AS boost in metastatic CRC. m6A modified BACE1-AS drives CRC cells migration and invasion and liver metastasis both in vitro and in vivo. Moreover, BACE1-AS maintains the stemness-like properties of CRC cells. Mechanically, BACE1-AS promoted TUFT1 expression by ceRNA network through miR-214-3p. CRC patients with such ceRNA network suffer poorer prognosis than ceRNA-negative patients. Depletion of TUFT1 mimics BACE1-AS loss. BACE1-AS activated Wnt signaling pathway in a TUFT1 dependent manner. BACE1-AS/miR-214-3p/TUFT1/Wnt signaling regulatory axis is essential for CRC liver metastasis. Pharmacologic inhibition of Wnt signaling pathway repressed liver metastasis and stemness-like features in BACE1-AS over-expressed CRC cells.

CONCLUSION

Our study demonstrated BACE1-AS as a novel target of IGF2BP2 through m6A modification. m6A modified BACE1-AS promotes CRC liver metastasis through TUFT1 dependent activation of Wnt signaling pathway. Thus, targeting BACE1-AS and its downstream Wnt signaling pathways may provide a new opportunity for metastatic CRC intervention and treatment.

The potential role of RNA modification in skin diseases, as well as the recent advances in its detection methods and therapeutic agents

RNA modification is considered as an epigenetic modification that plays an indispensable role in biological processes such as gene expression and genome editing without altering nucleotide sequence, but the molecular mechanism of RNA modification has not been discussed systematically in the development of skin diseases. This article mainly presents the whole picture of theoretical achievements on the potential role of RNA modification in dermatology. Furthermore, this article summarizes the latest advances in clinical practice related with RNA modification, including its detection methods and drug development. Based on this comprehensive review, we aim to illustrate the current blind spots and future directions of RNA modification, which may provide new insights for researchers in this field.

LINC02489 with m6a modification increase paclitaxel sensitivity by inhibiting migration and invasion of ovarian cancer cells

The long non-coding RNA LINC02489 has been shown to be significantly downregulated in advanced ovarian cancer (OC). However, the function of LINC02489 remains unknown. This study aims to explain the role and mechanism of LINC02489 in OC. The expression of LINC02489 was examined by qRT-PCR in primary OC tissues. Additionally, MTT, wound healing, transwell, and flow cytometry assays were used to analyze the function of LINC02489. The mechanism of LINC02489 in OC was investigated by high-throughput RNA-sequencing, qRT-PCR, western blot, and N6-methyladenosine (m6A) meRIP. A total of 1101 and 827 genes are significantly down-regulated and up-regulated in metastatic and chemoresistant OC tissues. The expression of LINC02489 is decreased in metastatic and chemoresistant OC tissues compared with the primary OC tissues (p < 0.05). Overexpression of LINC02489 inhibits proliferation, invasion, and migration of drug-resistant OC cells. In the LINC02489 overexpressed chemoresistant SKOV3 cells, the m6A modified LINC02489 is significantly up-regulated. Furthermore, the expression of PKNOX2 is increased during overexpression of LINC02489, while the expression of PTEN and mTOR plummets. This study demonstrates that LINC02489 can inhibit the invasion and migration of chemoresistant OC cells by increasing its m6A modification and up-regulating PKNOX2 expression. In addition, LINC02489 regulates the invasion ability of OC cells through the PTEN/mTOR signaling pathway, thereby regulating the sensitivity of SKOV3 cells to paclitaxel. This result provides a potential therapeutic target for chemoresistant OC.

METTL14‑mediated RNA methylation in digestive system tumors

N6‑methyladenosine (m6A) RNA methylation is one of the most common post‑transcriptional modification mechanism in eukaryotes. m6A is involved in almost all stages of the mRNA life cycle, specifically regulating its stability, splicing, export and translation. Methyltransferase‑like 14 (METTL14) is a particularly important m6A methylation 'writer' that can recognize RNA substrates. METTL14 has been documented to improve the activity and catalytic efficiency of METTL3. However, as individual proteins they can also regulate different biological processes. Malignancies in the digestive system are some of the most common malignancies found in humans, which are typically associated with poor prognoses with limited clinical solutions. METTL14‑mediated methylation has been implicated in both the potentiation and inhibition of digestive system tumor growth, cell invasion and metastasis, in addition to drug resistance. In the present review, the research progress and regulatory mechanisms of METTL14‑mediated methylation in digestive system malignancies were summarized. In addition, future research directions and the potential for its clinical application were examined.

Mesenchymal Stem Cell-Derived from Dental Tissues-Related lncRNAs: A New Regulator in Osteogenic Differentiation

Odontogenic stem cells are mesenchymal stem cells (MSCs) with multipotential differentiation potential from different dental tissues. Their osteogenic differentiation is of great significance in bone tissue engineering. In recent years, it has been found that long noncoding RNAs (lncRNAs) participate in regulating the osteoblastic differentiation of stem cells at the epigenetic level, transcriptional level, and posttranscriptional level. We reviewed the existing lncRNA related to the osteogenic differentiation of odontogenic stem cells and emphasized the critical mechanism of lncRNA in the osteogenic differentiation of odontogenic stem cells. These findings are expected to be an important target for promoting osteoblastic differentiation of odontogenic stem cells in bone regeneration therapy with lncRNA.

N6-methyladenosine (m6A) writer KIAA1429 accelerates gastric cancer oxaliplatin chemoresistance by targeting FOXM1

PURPOSE

Chemical modification plays a critical role in regulating human cancer progression, especially N6-methyladenosine (m6A). However, m6A writer KIAA1429-mediated m6A modification in gastric cancer (GC) tumorigenesis remains largely unknown.

METHODS

The levels of mRNA and protein were detected using RT-qPCR and western blot. The half maximal inhibitory concentration (IC50) of oxaliplatin (OXA) resistance is detected using CCK-8 assay. The binding within moleculars was identified using RIP-PCR.

RESULTS

Results found that KIAA1429 was upregulated in GC tissue samples and its high expression acted as a prognostic factor of poor survival in patients with GC. Functional assays indicated that KIAA1429 promoted the proliferation of GC cells, besides, KIAA1429 accelerated the half maximal inhibitory concentration (IC50) of oxaliplatin (OXA) resistance. Mechanistically, online prediction found that there was possible m6A modification site on FOXM1 mRNA. KIAA1429 could target the m6A modification site on FOXM1. Notably, KIAA1429 facilitated the GC OXA resistance in GC cells by promoting FOXM1 mRNA stability.

CONCLUSIONS

Taken together, our study reveals the functions and mechanism for KIAA1429 and exposes KIAA1429 as a key player in GC chemoresistance.

Novel insights into mutual regulation between N6-methyladenosine modification and LncRNAs in tumors

N⁶-methyladenosine (m⁶A), one of the most common RNA methylation modifications, has emerged in recent years as a new layer of the regulatory mechanism controlling gene expression in eukaryotes. As a reversible epigenetic modification, m⁶A not only occurs on mRNAs but also on Long non-coding RNAs (LncRNAs). As we all known, despite LncRNAs cannot encode proteins, they affect the expression of proteins by interacting with mRNAs or miRNAs, thus playing important roles in the occurrence and development of a variety of tumors. Up to now, it has been widely accepted that m⁶A modification on LncRNAs affects the fate of the corresponding LncRNAs. Interestingly, levels and functions of m⁶A modifications are also mediated by LncRNAs through affecting the m⁶A methyltransferases (METTL3, METTL14, WTAP, METTL16, etc.), demethylases (FTO, ALKBH5) and methyl-binding proteins (YTHDFs, YTHDCs, IGF2BPs, HNRNPs, etc.), which are collectively referred to as "m⁶A regulators". In this review, we summarized the mutual regulation mechanisms between N⁶-methyladenosine modification and LncRNAs in cancer progression, metastasis, invasion and drug resistance. In detail, we focus on the specific mechanisms of m⁶A modification, which is mediated by methyltransferases and demethylases, involves in the regulation of LncRNA levels and functions in the first part. And section two intensively displays the mediation roles of LncRNAs in m⁶A modification via changing the regulatory proteins. At last part, we described the interaction effects between LncRNAs and methyl-binding proteins of m⁶A modification during various tumor occurrence and development.

METTL16 epigenetically enhances GPX4 expression via m6A modification to promote breast cancer progression by inhibiting ferroptosis

Breast cancer is malignant cancer that severely threatens the life quality of female patients. N6-methyladenosine (m6A) is a prevalent modification of RNA. METTL16 is an important methyltransferase. This work aims to study the role of METTL16 in breast cancer cell death. The expression of METTL16 in clinical breast cancer specimens was analyzed by qPCR assay. The in vitro and in vivo breast cancer cell proliferation was measured by CCK8, colony formation, and xenograft mouse model. Cell ferroptosis was assessed by measuring the accumulation of iron, Fe²⁺, and lipid ROS. The mechanistic study was performed by RNA degradation, qPCR, and Western blotting assay. METTL16 was overexpressed in tumor tissues from breast cancer patients compared with the para-tumor tissues. Knockdown of METTL16 suppressed in vitro cell proliferation and in vivo tumor growth of breast cancer cells. Meanwhile, METTL16 silencing led to elevated intracellular levels of iron, Fe²⁺, and lipid ROS, indicating the incidence of ferroptosis. Furthermore, siMETTL16 decreased m6A methylation and enhanced the degradation of GPX4 RNA. METTL16-regulated m6A methylation of GPX4 stimulates proliferation and suppresses ferroptosis of breast cancer cells. Therefore, we concluded that METTL16 epigenetically enhanced GPX4 expression via m6A modification to promote breast cancer progression by inhibiting ferroptosis.

LncRNA-miRNA axis in tumor progression and therapy response: An emphasis on molecular interactions and therapeutic interventions

Epigenetic factors are critical regulators of biological and pathological mechanisms and they could interact with different molecular pathways. Targeting epigenetic factors has been an idea approach in disease therapy, especially cancer. Accumulating evidence has highlighted function of long non-coding RNAs (lncRNAs) as epigenetic factors in cancer initiation and development and has focused on their association with downstream targets. microRNAs (miRNAs) are the most well-known targets of lncRNAs and present review focuses on lncRNA-miRNA axis in malignancy and therapy resistance of tumors. LncRNA-miRNA regulates cell death mechanisms such as apoptosis and autophagy in cancers. This axis affects tumor metastasis via regulating EMT and MMPs. Besides, lncRNA-miRNA axis determines sensitivity of tumor cells to chemotherapy, radiotherapy and immunotherapy. Based on the studies, lncRNAs can be affected by drugs and genetic tools in cancer therapy and this may affect expression level of miRNAs as their downstream targets, leading to cancer suppression/progression. LncRNAs have both tumor-promoting and tumor-suppressor functions in cancer and this unique function of lncRNAs has complicated their implication in tumor therapy. LncRNA-miRNA axis can also affect other signaling networks in cancer such as PI3K/Akt, STAT3, Wnt/β-catenin and EZH2 among others. Notably, lncRNA/miRNA axis can be considered as a signature for diagnosis and prognosis in cancers.

Implications of m6A methylation and microbiota interaction in non-small cell lung cancer: From basics to therapeutics

N6-methyladenine (m6A) is one of the most common RNA epigenetic modifications in all higher eukaryotes. Increasing evidence demonstrated that m6A-related proteins, acted as oncogenes or tumor suppressors, are abnormally expressed in the cell lines and tissues of non-small cell lung cancer (NSCLC). In addition, lung as the special immune organ contacts with the outer environments and thereby inevitably suffers from different types of microbial pathogen attack. Those microbial pathogens affect the development, progression, and clinical outcomes of NSCLC via altering host m6A modification to disrupt pulmonary immune homeostasis and increase the susceptibility; conversely, host cells modulate m6A modification to repress bacterial colonization. Therefore, m6A harbors the potential to be the novel biomarkers and targets for predicting poor prognosis and chemotherapy sensitivity of patients with lung cancer. In this paper, we provided an overview of the biological properties of m6A-modifying enzymes, and the mechanistic links among lung microbiota, m6A modification and NSCLC. Although the flood of novel m6A-related inhibitors represents many dramatic improvements in NSCLC therapy, their efficacy and toxicity in NSCLC are explored to address these pivotal gaps in the field.

Advances in detecting N6-methyladenosine modification in circRNAs

Circular RNAs (circRNAs) are a class of noncoding RNAs with covalently single-stranded closed loop structures derived from back-splicing event of linear precursor mRNAs (pre-mRNAs). N6-methyladenosine (m⁶A), the most abundant epigenetic modification in eukaryotic RNAs, has been shown to play a crucial role in regulating the fate and biological function of circRNAs, and thus affecting various physiological and pathological processes. Accurate identification of m⁶A modification in circRNAs is an essential step to fully elucidate the crosstalk between m⁶A and circRNAs. In recent years, the rapid development of high-throughput sequencing technology and bioinformatic methodology has propelled the establishment of a multitude of approaches to detect circRNAs and m⁶A modification, including in vitro-based and in silico methods. Based on this, the research community has started on a new journey to develop methods for identification of m⁶A modification in circRNAs. In this review, we provide a comprehensive review and evaluation of the existing methods responsible for detecting circRNAs, m⁶A modification, and especially, m⁶A modification in circRNAs, which mainly focused on those developed based on high-throughput technologies and methodology of bioinformatics. This handy reference can help researchers figure out towards which direction this field will go.

Mutual regulation between N6-methyladenosine (m6A) modification and circular RNAs in cancer: impacts on therapeutic resistance

The resistance of tumor cells to therapy severely impairs the efficacy of treatment, leading to recurrence and metastasis of various cancers. Clarifying the underlying mechanisms of therapeutic resistance may provide new strategies for overcoming cancer resistance. N6-methyladenosine (m6A) is the most prevalent RNA modification in eukaryotes, and is involved in the regulation of RNA splicing, translation, transport, degradation, stability and processing, thus affecting several physiological processes and cancer progression. As a novel type of multifunctional non-coding RNAs (ncRNAs), circular RNAs (circRNAs) have been demonstrated to play vital roles in anticancer therapy. Currently, accumulating studies have revealed the mutual regulation of m6A modification and circRNAs, and their interaction can further influence the sensitivity of cancer treatment. In this review, we mainly summarized the recent advances of m6A modification and circRNAs in the modulation of cancer therapeutic resistance, as well as their interplay and potential mechanisms, providing promising insights and future directions in reversal of therapeutic resistance in cancer.

N6-methyladenosine (m6A) methyltransferase METTL3 regulates sepsis-induced myocardial injury through IGF2BP1/HDAC4 dependent manner

Recent studies have identified that N⁶-methyladenosine (m⁶A) extensively participates in the myocardial injury pathophysiological process. However, the role of m⁶A on sepsis-induced myocardial injury is still unclear. Here, we investigated the functions and mechanism of m⁶A methyltransferase METTL3 for septic myocardial injury. Results illustrated that the m⁶A modification level and METTL3 up-regulated in the lipopolysaccharide (LPS)-induced cardiomyocytes (H9C2 cells). Methylated RNA immunoprecipitation sequencing (MeRIP-Seq) revealed the m⁶A profile of the septic myocardial injury cellular model. Functionally, METTL3 knockdown repressed the inflammatory damage of cardiomyocytes induced by LPS. Mechanistically, we found that HDAC4 had remarkable m⁶A modification sites on its 3'-UTR genome, acting as the downstream target of METTL3. Besides, m⁶A reader IGF2BP1 recognized the m⁶A modification sites on HDAC4 mRNA and enhanced its RNA stability. In conclusion, the findings illustrated a role of METTL3/IGF2BP1/m⁶A/HDAC4 axis on sepsis-induced myocardial injury, which might provide novel therapeutic strategy for septic myocardial injury.

Epigenetics Regulates Antitumor Immunity in Melanoma

Melanoma is the most malignant skin cancer, which originates from epidermal melanocytes, with increasing worldwide incidence. The escape of immune surveillance is a hallmark of the tumor, which is manifested by the imbalance between the enhanced immune evasion of tumor cells and the impaired antitumor capacity of infiltrating immune cells. According to this notion, the invigoration of the exhausted immune cells by immune checkpoint blockades has gained encouraging outcomes in eliminating tumor cells and significantly prolonged the survival of patients, particularly in melanoma. Epigenetics is a pivotal non-genomic modulatory paradigm referring to heritable changes in gene expression without altering genome sequence, including DNA methylation, histone modification, non-coding RNAs, and m⁶A RNA methylation. Accumulating evidence has demonstrated how the dysregulation of epigenetics regulates multiple biological behaviors of tumor cells and contributes to carcinogenesis and tumor progression in melanoma. Nevertheless, the linkage between epigenetics and antitumor immunity, as well as its implication in melanoma immunotherapy, remains elusive. In this review, we first introduce the epidemiology, clinical characteristics, and therapeutic innovations of melanoma. Then, the tumor microenvironment and the functions of different types of infiltrating immune cells are discussed, with an emphasis on their involvement in antitumor immunity in melanoma. Subsequently, we systemically summarize the linkage between epigenetics and antitumor immunity in melanoma, from the perspective of distinct paradigms of epigenetics. Ultimately, the progression of the clinical trials regarding epigenetics-based melanoma immunotherapy is introduced.

EpisomiR, a New Family of miRNAs, and Its Possible Roles in Human Diseases

MicroRNAs (miRNAs) are synthesized through a canonical pathway and play a role in human diseases, such as cancers and cardiovascular, neurodegenerative, psychiatric, and chronic inflammatory diseases. The development of sequencing technologies has enabled the identification of variations in noncoding miRNAs. These miRNA variants, called isomiRs, are generated through a non-canonical pathway, by several enzymes that alter the length and sequence of miRNAs. The isomiR family is, now, expanding further to include episomiRs, which are miRNAs with different modifications. Since recent findings have shown that isomiRs reflect the cell-specific biological function of miRNAs, knowledge about episomiRs and isomiRs can, possibly, contribute to the optimization of diagnosis and therapeutic technology for precision medicine.

The Potential Value of m6A RNA Methylation in the Development of Cancers Focus on Malignant Glioma

N6-methyladenosine (m6A) RNA methylation is an epigenetic modification that has emerged in the last few years and has received increasing attention as the most abundant internal RNA modification in eukaryotic cells. m6A modifications affect multiple aspects of RNA metabolism, and m6A methylation has been shown to play a critical role in the progression of multiple cancers through a variety of mechanisms. This review summarizes the mechanisms by which m6A RNA methylation induced peripheral cancer cell progression and its potential role in the infiltration of immune cell of the glioblastoma microenvironment and novel immunotherapy. Assessing the pattern of m6A modification in glioblastoma will contribute to improving our understanding of microenvironmental infiltration and novel immunotherapies, and help in developing immunotherapeutic strategies.

N6-methyladenine- induced LINC00667 promoted breast cancer progression through m6A/KIAA1429 positive feedback loop

Increasing evidence supports that N⁶-methyladenine (m⁶A) and long noncoding RNAs (lncRNAs) both act as master regulators involved in breast cancer (BC) tumorigenesis at epigenetic modification level. Here, our research tries to unveil the interaction of m⁶A and lncRNAs on BC progression and explore the underlying regulatory mechanism. In the current study, we found that LINC00667 was m⁶A-modified lncRNA, which was up-regulated upon the overexpression of KIAA1429. The high expression of LINC00667 was correlated with the prognosis of BC patients. Bio-functional assays indicated that LINC00667 promoted the proliferation and migration of BC cells. Mechanistic assays illustrated that KIAA1429 targeted the m⁶A modification site of LINC00667 and enhanced its mRNA stability. Moreover, LINC00667 positively regulated the KIAA1429 via sponging miR-556-5p, forming a KIAA1429/m⁶A/LINC00667/miR-556-5p feedback loop. Collectively, the central findings of our study suggest that KIAA1429-induced LINC00667 exerted its functions as an oncogene in BC progression through m⁶A-dependent feedback loop.