m6A Modification in Non-Coding RNA: The Role in Cancer Drug Resistance

Research progress on m6A and drug resistance in gastrointestinal tumors

Gastrointestinal (GI) tumors represent a significant global health burden and are among the leading causes of cancer-related mortality worldwide. their drug resistance is one of the major challenges in cancer therapy. In recent years, epigenetic modifications, especially N6-methyladenosine (m6A) RNA modifications, have become a hot research topic. m6A modification plays an important role in gene expression and cancer progression by regulating RNA splicing, translation, stability, and degradation, which are regulated by "writers," "erasers" and "readers." In GI tumors, resistance to chemotherapy, targeted therapy, and immunotherapy is closely associated with m6A RNA modification. Therefore, the molecular mechanism of m6A modification and its targeted drug development provide new therapeutic strategies for overcoming drug resistance and therapeutic efficacy in GI tumors. In this review, the biological functions of m6A were explored, the specific resistance mechanisms of m6A in different types of GI tumors were explored, new ideas and targets for future treatment resistance were identified, and the limitations of this field were highlighted.

YTHDF1-mediated m6A modification promotes cisplatin resistance in ovarian cancer via the FZD7/Wnt/β-catenin pathway

Cisplatin resistance significantly hinders the efficacy of ovarian cancer treatment, presenting a major challenge in improving patient outcomes. This study identifies the m6A reader protein YTHDF1 as a key regulator of cisplatin resistance in ovarian cancer through its modulation of the FZD7/Wnt/β-catenin signaling pathway. Using cisplatin-resistant ovarian cancer cell lines (A2780/DDP and SKOV3/DDP), we observed elevated YTHDF1 expression, which positively correlated with tumor cell proliferation and migration. Silencing YTHDF1 reduced FZD7 expression, inhibited Wnt/β-catenin signaling, and restored cisplatin sensitivity both in vitro and in vivo. Mechanistic investigations revealed that YTHDF1 binds to m6A-modified FZD7 mRNA, enhancing its stability and translation. Functional studies in xenograft mouse models demonstrated that targeting YTHDF1 suppressed tumor growth and enhanced apoptosis in cisplatin-resistant ovarian cancer cells. These findings highlight the YTHDF1-FZD7 axis as a novel therapeutic target for overcoming cisplatin resistance, paving the way for improved treatment strategies in ovarian cancer.

Epigenetic regulation of reprogramming and pluripotency: insights from histone modifications and their implications for cancer stem cell therapies

Pluripotent stem cells (PSCs) possess the extraordinary capability to differentiate into a variety of cell types. This capability is tightly regulated by epigenetic mechanisms, particularly histone modifications. Moreover, the reprogramming of somatic or fate-committed cells into induced pluripotent stem cells (iPSCs) largely relies on these modifications, such as histone methylation and acetylation of histones. While extensive research has been conducted utilizing mouse models, the significance of histone modifications in human iPSCs is gaining increasing recognition. Recent studies underscore the importance of epigenetic regulators in both the reprogramming process and the regulation of cancer stem cells (CSCs), which are pivotal in tumor initiation and the development of treatment resistance. This review elucidates the dynamic alterations in histone modifications that impact reprogramming and emphasizes the necessity for a balance between activating and repressive marks. These epigenetic marks are influenced by enzymes such as DNA methyltransferases (DNMTs) and histone deacetylases (HDACs). Furthermore, this review explores therapeutic strategies aimed at targeting these epigenetic modifications to enhance treatment efficacy in cancer while advancing the understanding of pluripotency and reprogramming. Despite promising developments in the creation of inhibitors for histone-modifying enzymes, challenges such as selectivity and therapy resistance continue to pose significant hurdles. Therefore, future endeavors must prioritize biomarker-driven approaches and gene-editing technologies to optimize the efficacy of epigenetic therapies.

LncRNA CCAT1 knockdown suppresses tongue squamous cell carcinoma progression by inhibiting the ubiquitination of PHLPP2

Tongue squamous cell carcinoma (TSCC) is prevailing malignancy in the oral and maxillofacial region, characterized by its high frequency. LncRNA CCAT1 can promote tumorigenesis and progression in many cancers. Here, we investigated the regulatory mechanism by which CCAT1 influences growth and metastasis of TSCC. Levels of CCAT1, WTAP, TRIM46, PHLPP2, AKT, p-AKT, and Ki67 in TSCC tissues and cells were assessed utilizing qRT-PCR, Western blot and IHC. Cell proliferation, migration, and invasion were evaluated utilizing CCK8, colony formation, wound healing and transwell assays. Subcellular localization of CCAT1 was detected utilizing FISH assay. m6A level of CCAT1 was assessed using MeRIP. RNA immunoprecipitation (RIP), Co-immunoprecipitation (Co-IP) and RNA pull down elucidated binding relationship between molecules. Nude mouse tumorigenesis experiments were used to verify the TSCC regulatory function of CCAT1 in vivo. Metastatic pulmonary nodules were observed utilizing hematoxylin and eosin (HE) staining. CCAT1 silencing repressed TSCC cell proliferation, migration and invasion. Expression of CCAT1 was enhanced through N6-methyladenosine (m6A) modification of its RNA, facilitated by WTAP. Moreover, IGF2BP1 up-regulated CCAT1 expression by stabilizing its RNA transcript. CCAT1 bond to PHLPP2, inducing its ubiquitination and activating AKT signaling. CCAT1 mediated the ubiquitination and degradation of PHLPP2 by TRIM46, thereby promoting TSCC growth and metastasis. CCAT1/TRIM46/PHLPP2 axis regulated proliferation and invasion of TSCC cells, implying that CCAT1 would be a novel therapeutic target for TSCC patients.

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.

N6-methyladenosine methylation analysis of long noncoding RNAs and mRNAs in 5-FU-resistant colon cancer cells

N6 methyladenosine (m6A), methylation at the sixth N atom of adenosine, is the most common and abundant modification in mammalian mRNAs and non-coding RNAs. Increasing evidence shows that the alteration of m6A modification level could regulate tumour proliferation, metastasis, self-renewal, and immune infiltration by regulating the related expression of tumour genes. However, the role of m6A modification in colorectal cancer (CRC) drug resistance is unclear. Here, MeRIP-seq and RNA-seq techniques were utilized to obtain mRNA, lncRNA expression, and their methylation profiles in 5-Fluorouracil (5-FU)-resistant colon cancer HCT-15 cells and control cells. In addition, we performed detailed bioinformatics analysis as well as in vitro experiments of lncRNA to explore the function of lncRNA with differential m6A in CRC progression and drug resistance. In this study, we obtained the m6A methylomic landscape of CRC cells and resistance group cells by MeRIP-seq and RNA-seq. We identified 3698 differential m6A peaks, of which 2224 were hypermethylated, and 1474 were hypomethylated. Among the lncRNAs, 60 were hypermethylated, and 38 were hypomethylated. GO and KEGG analysis annotations showed significant enrichment of endocytosis and MAPK signalling pathways. Moreover, knockdown of lncRNA ADIRF-AS1 and AL139035.1 promoted CRC proliferation and invasive metastasis in vitro. lncRNA- mRNA network showed that ADIRF-AS1 and AL139035.1 May play a key role in regulating drug resistance formation. We provide the first m6A methylation profile in 5-FU resistance CRC cells and analyse the functions of differential m6A-modified mRNAs and lncRNAs. Our results indicated that differential m6A RNAs were significantly associated with MAPK signalling and endocytosis after induction of 5-FU resistance. Knockdown of LncRNA ADIRF-AS1 and AL139035.1 promotes CRC progression and might be critical in regulating drug resistance formation.

WTAP-dependent N6-methyladenosine methylation of lncRNA TEX41 promotes renal cell carcinoma progression

The methyltransferase Wilms' tumor 1-associated protein (WTAP) has been reported to be dysregulated in various tumors. However, its role in renal cell carcinoma (RCC) remains elusive. Here, we explored whether WTAP was upregulated in RCC specimens compared to normal tissues. Functionally, WTAP promoted RCC cell proliferation and metastasis in vivo and in vitro. Mechanistically, WTAP act as an N6-methyladenosine transferase to regulate the m6A modification of long noncoding RNA TEX41. Then, the upregulated m6A modification destabilized TEX41 in a YTHDF2-dependent manner. Furthermore, TEX41 interacted with the SUZ12 protein and increased the histone methyltransferase activity of SUZ12, resulting in HDAC1 silencing. Totally, our study demonstrated the oncogenic the role of WTAP/TEX41/SUZ12/HDAC1 axis in RCC progression.

FTO/m6A mediates miR-138-5p maturation and regulates gefitinib resistance of lung adenocarcinoma cells by miR-138-5p/LCN2 axis

BACKGROUND

Lung cancer (LC) occupies an important position in the lethality of cancer patients. Acquired resistance to gefitinib in lung adenocarcinoma (LUAD) seriously affects the therapeutic efficacy of LC. Thus, it is of major scientific and clinical significance to probe the mechanism of gefitinib resistance in LUAD for ameliorating the prognosis of patients.

METHODS

The expression of miRNAs in gefitinib-resistant LUAD cells was validated using qRT-PCR. Cell viability was assessed through CCK-8, whereas cell death was examined through PI staining. Changes in the ferroptosis process were evaluated by detecting the intracellular Glutathione (GSH), Malondialdehyde (MDA), and Reactive Oxygen Species (ROS) levels. Downstream targets of miR-138-5p were verified via luciferase reporter and RNA pull-down assays. RIP and qRT-PCR were employed to evaluate pri-miR-138-5p binding to DiGeorge critical region 8 (DGCR8) and the pri-miR-138-5p m6A modification level. Additionally, the impact of fat mass and obesity-associated protein (FTO) on LUAD gefitinib sensitivity was assessed in vivo by constructing a xenograft model.

RESULTS

We observed that miR-138-5p was notably diminished in gefitinib-resistant cells. Overexpression of miR-138-5p suppressed viability while facilitated cell death and intracellular ferroptosis in gefitinib-resistant cells. Moreover, lipocalin 2 (LCN2) was the downstream target of miR-138-5p. The biological functions of miR-138-5p on gefitinib-resistant cells was reversed by introduction of LCN2. FTO suppressed the binding of DGCR8 to pri-miR-138-5p through m6A modification, thereby restraining the processing of miR-138-5p. Meanwhile, silencing of FTO enhanced the sensitivity of LUAD to gefitinib treatment.

CONCLUSION

FTO suppressed the processing of miR-138-5p and then modulated the proliferation, death, and ferroptosis of gefitinib-resistant cells through the miR-138-5p/LCN2 pathway, which may put forward novel insights for clinically ameliorating the therapeutic effect of gefitinib in LUAD.

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.

Examining the evidence for mutual modulation between m6A modification and circular RNAs: current knowledge and future prospects

The resistance of cancer cells to treatment significantly impedes the success of therapy, leading to the recurrence of various types of cancers. Understanding the specific mechanisms of therapy resistance may offer novel approaches for alleviating drug resistance in cancer. Recent research has shown a reciprocal relationship between circular RNAs (circRNAs) and N6-methyladenosine (m6A) modification, and their interaction can affect the resistance and sensitivity of cancer therapy. This review aims to summarize the latest developments in the m6A modification of circRNAs and their importance in regulating therapy resistance in cancer. Furthermore, we explore their mutual interaction and exact mechanisms and provide insights into potential future approaches for reversing cancer resistance.

The role of m6A methylation in targeted therapy resistance in lung cancer

Targeted therapies have greatly improved clinical outcomes for patients with lung cancer (LC), but acquired drug resistance and disease relapse inevitably occur. Increasingly, the role of epigenetic mechanisms in driving acquired drug resistance is appreciated. In particular, N6-methyladenosine (m6A), one of the most prevalent RNA modifications, has several roles regulating RNA stability, splicing, transcription, translation, and destruction. Numerous studies have demonstrated that m6A RNA methylation can modulate the growth and invasion of cancer cells as well as contribute to targeted therapy resistance in LC. In this study, we outline what is known regarding the function of m6A in the acquisition of targeted therapy resistance in LC.

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.

The role of m6A methylation in therapy resistance in cancer

Cancer therapy resistance is the main cause of cancer treatment failure. The mechanism of therapy resistance is a hot topic in epigenetics. As one of the most common RNA modifications, N6-methyladenosine (m6A) is involved in various processes of RNA metabolism, such as stability, splicing, transcription, translation, and degradation. A large number of studies have shown that m6A RNA methylation regulates the proliferation and invasion of cancer cells, but the role of m6A in cancer therapy resistance is unclear. In this review, we summarized the research progress related to the role of m6A in regulating therapy resistance in cancers.

Identification of m6A-related lncRNAs for thyroid cancer recurrence

Background

Although the prognosis of thyroid cancer (THCA) is generally good, many patients have a high risk of recurrence after treatment. N6-methyladenosine (m6A)-related long noncoding RNAs (lncRNAs) have been extensively studied in recent years. However, the potential of m6A-related lncRNAs to predict recurrence in THCA is unknown.

Methods

RNA sequencing (RNA-seq) data and clinical information for THCA were downloaded from The Cancer Genome Atlas (TCGA). Differentially expressed lncRNAs (DELs) were identified using the R package DESeq2. A coexpression network based on m6A-related genes and lncRNAs was constructed. The CIBERSORT algorithm and gene set enrichment analysis (GSEA) were used for immune-infiltrating cell estimation and clustering functional enrichment analysis, respectively. A Kaplan-Meier plot was used for prognostic analysis based on m6A-associated lncRNA risk patterns. The expression of lncRNAs in recurrent and nonrecurrent THCA tissues was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR).

Results

A network of m6A-related lncRNAs containing 8 lncRNAs was constructed with good predictive power for recurrence in THCA. A total of 3 clusters were obtained, and cluster 1 was most associated with THCA recurrence. We found significantly lower levels of CD8 T cells and follicular helper T cells, and significantly higher levels of dendritic cells (DCs), M2 macrophages, resting DCs, regulatory T cells, and mast cells in cluster 1 patients. Pathway analysis revealed significant enrichment in natural killer cell-mediated cytotoxicity, butyrate metabolism, and cell adhesion molecules in cluster 1. The m6A-related lncRNA risk model was effective in predicting progression-free survival (PFS) in patients with THCA recurrence. RT-qPCR analysis based on 40 THCA clinical samples from our center found the risk model to be a good predictor of recurrence in THCA patients.

Conclusions

In summary, m6A-related lncRNAs may provide a novel predictive method for prognostic relapse in THCA patients.

CDH13 is a prognostic biomarker and a potential therapeutic target for patients with clear cell renal cell carcinoma

CDH13 is an atypical member of the cadherin family and is closely related to the clinicopathological factors and prognosis of many types of cancer. However, the role of CDH13 in clear cell renal cell carcinoma (ccRCC) remains unknown. Therefore, we comprehensively analyzed the expression level, diagnostic efficacy, clinical significance, prognostic value, immune infiltration, methylation status, genetic alteration, and biological functions of CDH13 in ccRCC patients. The results showed that CDH13 was significantly upregulated in ccRCC and strongly correlated with better survival, lower cancer stages, and lower tumor grades of ccRCC patients. Additionally, the immune infiltration analysis indicated that CDH13 might play a crucial role in regulating the tumor microenvironment of ccRCC. The results of methylation analysis showed that the epigenetic status of CDH13 was altered, and the prognosis of ccRCC patients was related not only to DNA methylation but also to m6A modification of CDH13. Finally, the results based on clinical samples further elucidated the expression pattern of CDH13 in ccRCC. In conclusion, CDH13 might be a novel prognostic biomarker and therapeutic target for patients with ccRCC. And our study provides new insights into the potential molecular changes and strategies for the treatment of ccRCC.

High-throughput microarray reveals the epitranscriptome-wide landscape of m6A-modified circRNA in oral squamous cell carcinoma

Background

Emerging transcriptome-wide high-throughput screenings reveal the landscape and functions of RNAs, such as circular RNAs (circRNAs), in human cancer. In addition, the post-transcriptional RNA internal modifications, especially N⁶-methyladenosine (m⁶A), greatly enrich the variety of RNAs metabolism. However, the m⁶A modification on circRNAs has yet to be addressed.

Results

Here, we report an epitranscriptome-wide mapping of m⁶A-modified circRNAs (m⁶A-circRNA) in oral squamous cell carcinoma (OSCC). Utilizing the data of m⁶A methylated RNA immunoprecipitation sequencing (MeRIP-seq) and m⁶A-circRNAs microarray, we found that m⁶A-circRNAs exhibited particular modification styles in OSCC, which was independent of m⁶A-mRNA. Besides, m⁶A modification on circRNAs frequently occurred on the long exons in the front part of the coding sequence (CDS), which was distinct from m⁶A-mRNA that in 3’-UTR or stop codon.

Conclusion

In conclusion, our work preliminarily demonstrates the traits of m⁶A-circRNAs, which may bring enlighten for the roles of m⁶A-circRNAs in OSCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08806-z.

1. m⁶A-circRNAs exhibited their particular modification style in OSCC, which was independent of m⁶A-mRNA.

2. m⁶A on circRNAs frequently occurred on the long exons in the front part of CDS, which was distinct from m⁶A-mRNA that in 3’-UTR or stop codon.

YTHDF3 Facilitates eIF2AK2 and eIF3A Recruitment on mRNAs to Regulate Translational Processes in Oxaliplatin-Resistant Colorectal Cancer

Oxaliplatin, as a first-line drug, frequently causes chemo-resistance in colorectal cancer (CRC). The role of N6-methyladenosine (m6A) modification in multiple biological functions has been well studied. However, the molecular mechanisms underlying m6A methylation in modulating anti-cancer drug resistance in CRC remain obscure. In the present study, we found that YTH m6A RNA-binding protein 3 (YTHDF3) was highly expressed in oxaliplatin-resistant (OXAR) CRC tissues and cells. Moreover, we observed that YTHDF3 could recognize the 5' untranslated region of significantly m6A-methylated RNAs, which were associated with tumor resistance and recruit eukaryotic translation initiation factor 3 subunit A (eIF3A) to facilitate the translation of these target genes. Furthermore, we determined that eukaryotic translation initiation factor 2 alpha kinase 2 (eIF2AK2) bridged YTHDF3 and eIF3A, enhancing the stability of the YTHDF3/eIF3A complex in OXAR CRC cells. Taken together, our data identified YTHDF3 as a novel hallmark and revealed the molecular mechanism of YTHDF3 on gene translation via coordination with eIF2AK2 in OXAR CRC cells.

N6-methyladenosine (m6A) methyltransferase METTL3-mediated LINC00680 accelerates osteoarthritis through m6A/SIRT1 manner

Increasing evidence suggest the biological roles of N⁶-methyladenosine (m⁶A) and long noncoding RNAs (lncRNAs) in the bone disease, especially osteoarthritis (OA). However, the interaction of m⁶A and lncRNA in osteoarthritis is still unclear. Here, we found that a m⁶A-related lncRNA LINC00680 upregulated in the OA tissue and IL-1β-induced isolated primary chondrocytes. Functionally, in IL-1β-induced chondrocytes, silencing of LINC00680 recovered the proliferation and repressed the extracellular matrix (ECM) degradation. Mechanistically, m⁶A methyltransferase METTL3 combined tithe the m⁶A site of LINC00680 to up-regulate its expression. Moreover, LINC00680 interacted with SIRT1 mRNA through binding at m⁶A site on SIRT1 mRNA 3'-UTR, thereby enhancing the stability of SIRT1 mRNA. Overall, these findings exhibited a role of LINC00680/m⁶A/SIRT1 mRNA complex in chondrocytes. Taken together, the present study intends to uncover the mechanism by which METTL3-mediated LINC00680 accelerates OA progression, which may provide novel insight for OA.

m6A demethylase FTO regulates the apoptosis and inflammation of cardiomyocytes via YAP1 in ischemia-reperfusion injury

Reperfusion therapy after acute myocardial infarction can induce myocardial ischemia-reperfusion injury (IRI). Novel evidence has illustrated that N6-methyladenosine (m6A) modification modulates the myocardial IRI progression. Here, our study focuses on the role of m6A methyltransferase fat mass and obesity-associated protein (FTO) in myocardial ischemia/reoxygenation injury and explores potential regulatory mechanisms. Results discovered that FTO down-expressed in myocardial IRI mice and hypoxia/reoxygenation (H/R)-induced cardiomyocytes. Functionally, FTO overexpression attenuated the H/R-induced apoptosis and inflammation of cardiomyocytes. Mechanistically, methylated RNA immunoprecipitation quantitative polymerase chain reaction (MeRIP-qPCR) assay and RIP assay revealed that Yap1 mRNA acted as the target of FTO in cardiomyocytes. Moreover, FTO uninstalled the methylation of Yap1 mRNA, and enforced the stability of Yap1 mRNA. Taken together, our study reveals the role of FTO in H/R-induced myocardial cell injury via m6A-dependent manner, which may provide a new approach to improve myocardial IRI.

Epigenetic modification and BRAF gene mutation in thyroid carcinoma

Thyroid cancer remains the most prevailing endocrine malignancy, and a progressively increasing incidence rate has been observed in recent years, with 95% of thyroid cancer represented by differentiated thyroid carcinomas. The genetics and epigenetics of thyroid cancer are gradually increasing, and gene mutations and methylation changes play an important roles in its occurrence and development. Although the role of RAS and BRAF mutations in thyroid cancer have been partially clarified,but the pathogenesis and molecular mechanisms of thyroid cancer remain to be elucidated. Epigenetic modification refer to genetic modification that does not change the DNA sequence of a gene but causes heritable phenotypic changes in its expression. Epigenetic modification mainly includes four aspects: DNA methylation, chromatin remodelling, noncoding RNA regulation, and histone modification. This article reviews the importance of thyroid cancer epigenetic modification and BRAF gene mutation in the treatment of thyroid cancer.