IGF2BP1 overexpression stabilizes PEG10 mRNA in an m6A-dependent manner and promotes endometrial cancer progression

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.

pyPAGE: A framework for Addressing biases in gene-set enrichment analysis-A case study on Alzheimer's disease

Inferring the driving regulatory programs from comparative analysis of gene expression data is a cornerstone of systems biology. Many computational frameworks were developed to address this problem, including our iPAGE (information-theoretic Pathway Analysis of Gene Expression) toolset that uses information theory to detect non-random patterns of expression associated with given pathways or regulons. Our recent observations, however, indicate that existing approaches are susceptible to the technical biases that are inherent to most real world annotations. To address this, we have extended our information-theoretic framework to account for specific biases and artifacts in biological networks using the concept of conditional information. To showcase pyPAGE, we performed a comprehensive analysis of regulatory perturbations that underlie the molecular etiology of Alzheimer's disease (AD). pyPAGE successfully recapitulated several known AD-associated gene expression programs. We also discovered several additional regulons whose differential activity is significantly associated with AD. We further explored how these regulators relate to pathological processes in AD through cell-type specific analysis of single cell and spatial gene expression datasets. Our findings showcase the utility of pyPAGE as a precise and reliable biomarker discovery in complex diseases such as Alzheimer's disease.

IGF2BP1-Mediated Regulation of CCN1 Expression by Specific Binding to G-Quadruplex Structure in Its 3'UTR

The intricate regulation of gene expression is fundamental to the biological complexity of higher organisms, and is primarily governed by transcriptional and post-transcriptional mechanisms. The 3'-untranslated region (3'UTR) of mRNA is rich in cis-regulatory elements like G-quadruplexes (G4s), and plays a crucial role in post-transcriptional regulation. G4s have emerged as significant gene regulators, impacting mRNA stability, translation, and localization. In this study, we investigate the role of a robust parallel G4 structure situated within the 3'UTR of CCN1 mRNA in post-transcriptional regulation. This G4 structure is proximal to the stop codon of human CCN1, and evolutionarily conserved. We elucidated its interaction with the insulin-like growth factor 2 binding protein 1 (IGF2BP1), a noncanonical RNA N6-methyladenosine (m6A) modification reader, revealing a novel interplay between RNA modifications and G-quadruplex structures. Knockdown experiments and mutagenesis studies demonstrate that IGF2BP1 binds specifically to the G4 structure, modulating CCN1 mRNA stability. Additionally, we unveil the role of IGF2BP1's RNA recognition motifs in G4 recognition, highlighting this enthalpically driven interaction. Our findings offer fresh perspectives on the complex mechanisms of post-transcriptional gene regulation mediated by G4 RNA secondary structures.

Regulations of m6A and other RNA modifications and their roles in cancer

RNA modification is an essential component of the epitranscriptome, regulating RNA metabolism and cellular functions. Several types of RNA modifications have been identified to date; they include N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), N6,2'-O-dimethyladenosine (m6Am), N4-acetylcytidine (ac4C), etc. RNA modifications, mediated by regulators including writers, erasers, and readers, are associated with carcinogenesis, tumor microenvironment, metabolic reprogramming, immunosuppression, immunotherapy, chemotherapy, etc. A novel perspective indicates that regulatory subunits and post-translational modifications (PTMs) are involved in the regulation of writer, eraser, and reader functions in mediating RNA modifications, tumorigenesis, and anticancer therapy. In this review, we summarize the advances made in the knowledge of different RNA modifications (especially m6A) and focus on RNA modification regulators with functions modulated by a series of factors in cancer, including regulatory subunits (proteins, noncoding RNA or peptides encoded by long noncoding RNA) and PTMs (acetylation, SUMOylation, lactylation, phosphorylation, etc.). We also delineate the relationship between RNA modification regulator functions and carcinogenesis or cancer progression. Additionally, inhibitors that target RNA modification regulators for anticancer therapy and their synergistic effect combined with immunotherapy or chemotherapy are discussed.

Research Progress on the Role of M6A in Regulating Economic Traits in Livestock

Reversible regulation of N6-methyladenosine (m6A) methylation of eukaryotic RNA via methyltransferases is an important epigenetic event affecting RNA metabolism. As such, m6A methylation plays crucial roles in regulating animal growth, development, reproduction, and disease progression. Herein, we review the latest research advancements in m6A methylation modifications and discuss regulatory aspects in the context of growth, development, and reproductive traits of livestock. New insights are highlighted and perspectives for the study of m6A methylation modifications in shaping economically important traits are discussed.

Increased PTCHD4 expression via m6A modification of PTCHD4 mRNA promotes senescent cell survival

RNA modifications, including N6-methyladenosine (m6A), critically modulate protein expression programs in a range of cellular processes. Although the transcriptomes of cells undergoing senescence are strongly regulated, the landscape and impact of m6A modifications during senescence are poorly understood. Here, we report a robust m6A modification of PTCHD4 mRNA, encoding Patched Domain-Containing Protein 4, in senescent cells. The METTL3/METTL14 complex was found to incorporate the m6A modification on PTCHD4 mRNA; addition of m6A rendered PTCHD4 mRNA more stable and increased PTCHD4 production. MeRIP RT-qPCR and eCLIP analyses were used to map this m6A modification to the last exon of PTCHD4 mRNA. Further investigation identified IGF2BP1, but not other m6A readers, as responsible for the stabilization and increased abundance of m6A-modified PTCHD4 mRNA. Silencing PTCHD4, a transmembrane protein, enhanced growth arrest and DNA damage in pre-senescent cells and sensitized them to senolysis and apoptosis. Our results indicate that m6A modification of PTCHD4 mRNA increases the production of PTCHD4, a protein associated with senescent cell survival, supporting the notion that regulating m6A modification on specific mRNAs could be exploited to eliminate senescent cells for therapeutic benefit.

Consensus clustering and novel risk score model construction based on m6A methylation regulators to evaluate the prognosis and tumor immune microenvironment of early-stage lung adenocarcinoma

BACKGROUND

The aim of this study was to investigate the correlation between m6A methylation regulators and cell infiltration characteristics in tumor immune microenvironment (TIME), so as to help understand the immune mechanism of early-stage lung adenocarcinoma (LUAD).

METHODS

The expression and consensus cluster analyses of m6A methylation regulators in early-stage LUAD were performed. The clinicopathological features, immune cell infiltration, survival and functional enrichment in different subtypes were analyzed. We also constructed a prognostic model. Clinical tissue samples were used to validate the expression of model genes through real-time polymerase chain reaction (RT-PCR). In addition, cell scratch assay and Transwell assay were also performed.

RESULTS

Expression of m6A methylation regulators was abnormal in early-stage LUAD. According to the consensus clustering of m6A methylation regulators, patients with early-stage LUAD were divided into two subtypes. Two subtypes showed different infiltration levels of immune cell and survival time. A prognostic model consisting of HNRNPC, IGF2BP1 and IGF2BP3 could be used to predict the survival of early-stage LUAD. RT-PCR results showed that HNRNPC, IGF2BP1 and IGF2BP3 were significantly up-regulated in early-stage LUAD tissues. The results of cell scratch assay and Transwell assay showed that overexpression of HNRNPC promotes the migration and invasion of NCI-H1299 cells, while knockdown HNRNPC inhibits the migration and invasion of NCI-H1299 cells.

CONCLUSIONS

This work reveals that m6A methylation regulators may be potential biomarkers for prognosis in patients with early-stage LUAD. Our prognostic model may be of great value in predicting the prognosis of early-stage LUAD.

A novel lncRNA LOC101928222 promotes colorectal cancer angiogenesis by stabilizing HMGCS2 mRNA and increasing cholesterol synthesis

BACKGROUND

Metastasis is the leading cause of mortality in patients with colorectal cancer (CRC) and angiogenesis is a crucial factor in tumor invasion and metastasis. Long noncoding RNAs (lncRNAs) play regulatory functions in various biological processes in tumor cells, however, the roles of lncRNAs in CRC-associated angiogenesis remain to be elucidated in CRC, as do the underlying mechanisms.

METHODS

We used bioinformatics to screen differentially expressed lncRNAs from TCGA database. LOC101928222 expression was assessed by qRT-PCR. The impact of LOC101928222 in CRC tumor development was assessed both in vitro and in vivo. The regulatory mechanisms of LOC101928222 in CRC were investigated by cellular fractionation, RNA-sequencing, mass spectrometric, RNA pull-down, RNA immunoprecipitation, RNA stability, and gene-specific m6A assays.

RESULTS

LOC101928222 expression was upregulated in CRC and was correlated with a worse outcome. Moreover, LOC101928222 was shown to promote migration, invasion, and angiogenesis in CRC. Mechanistically, LOC101928222 synergized with IGF2BP1 to stabilize HMGCS2 mRNA through an m6A-dependent pathway, leading to increased cholesterol synthesis and, ultimately, the promotion of CRC development.

CONCLUSIONS

In summary, these findings demonstrate a novel, LOC101928222-based mechanism involved in the regulation of cholesterol synthesis and the metastatic potential of CRC. The LOC101928222-HMGCS2-cholesterol synthesis pathway may be an effective target for diagnosing and managing CRC metastasis.

Fer-mediated activation of the Ras-MAPK signaling pathway drives the proliferation, migration, and invasion of endometrial carcinoma cells

BACKGROUND

The role of Feline sarcoma-related protein (Fer) in various cancers has been extensively studied, but its specific involvement and underlying mechanisms in the progression of endometrial carcinoma (EC) are yet to be fully understood.

METHODS

The expression levels of Fer were assessed in EC tissues and cell lines using real-time quantitative PCR and western blot analysis. CCK-8 assay, Edu staining, transwell assays, and flow cytometry, were conducted to evaluate the impact of Fer on EC cells. Furthermore, a mice xenograft model and immunohistochemistry (IHC) staining were utilized for in vivo analysis. The levels of Ras, pMek1/2, and pErk1/2 were determined by western blot assay. Ras-MAPK signaling pathway inhibitor was utilized to study the regulatory role of Fer on EC cells.

RESULTS

Our findings revealed that Fer exhibited upregulation in both EC tissues and cell lines, concomitant with the activation of the Ras-MAPK signaling pathway. Silencing of Fer resulted in the suppression of cell proliferation, migration, invasion, and Ras-MAPK signaling pathway, while promoted hypoxia-induced apoptosis in RL95-2 and KLE cells. Fer overexpression stimulated cell proliferation, migration, invasion, and Ras-MAPK signaling pathway in Ishikawa and AN3-CA cells, which were reversed after treatment with either Ras or MAPK inhibitor. Moreover, silencing of Fer suppressed tumor growth and downregulated the expression of Ki-67, Ras, pMek1/2, and pErk1/2, but had no significant effect on Mek1/2 and Erk1/2, while upregulated caspase-3 expression in vivo.

CONCLUSION

In summary, the upregulation of Fer in EC cells resulted in the enhancement of cell proliferation, migration, and invasion through the activation of the Ras-MAPK signaling pathway.

m 6 A reader IGF2BP1 reduces the sensitivity of nasopharyngeal carcinoma cells to Taxol by upregulation of AKT2

Taxol is widely used in the treatment of nasopharyngeal carcinoma (NPC); nevertheless, the acquired resistance of NPC to Taxol remains one of the major obstacles in clinical treatment. In this study, we aimed to investigate the role and mechanism of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in Taxol resistance of NPC. Taxol-resistant NPC cell lines were established by exposing to gradually increased concentration of Taxol. Relative mRNA and protein levels were tested using qRT-PCR and western blot, respectively. NPC cell viability and apoptosis were assessed by cell counting kit-8 and flow cytometry analysis, respectively. Cell migration and invasion capacities were measured using transwell assay. Interaction between IGF2BP1 and AKT2 was examined by RNA immunoprecipitation assay. The N6-methyladenosine level of AKT2 was tested using methylated RNA immunoprecipitation-qPCR. IGF2BP1 expression was enhanced in Taxol-resistant NPC cell lines. Knockdown of IGF2BP1 strikingly enhanced the sensitivity of NPC cells to Taxol and repressed the migration and invasion of NPC cells. Mechanistically, IGF2BP1 elevated the expression of AKT2 by increasing its mRNA stability. Furthermore, overexpression of AKT2 reversed the inhibitory roles of IGF2BP1 silence on Taxol resistance and metastasis. Our results indicated that IGF2BP1 knockdown enhanced the sensitivity of NPC cells to Taxol by decreasing the expression of AKT2, implying that IGF2BP1 might be promising candidate target for NPC treatment.

Systematic analysis of IGF2BP family members in non-small-cell lung cancer

BACKGROUND

The insulin-like growth factor-2 mRNA-binding proteins 1, 2, and 3 (IGF2BP1, IGF2BP2, and IGF2BP3) are known to be involved in tumorigenesis, metastasis, prognosis, and cancer immunity in various human cancers, including non-small cell lung cancer (NSCLC). However, the literature on NSCLC largely omits the specific context of lung squamous cell carcinoma (LUSC), an oversight we aim to address.

METHODS

Our study evaluated the differential expression of IGF2BP family members in tumors and normal tissues. Meta-analyses were conducted to assess the prognostic value of IGF2BPs in lung adenocarcinoma (LUAD) and LUSC. Additionally, correlations between IGF2BPs and tumor immune cell infiltration, mutation characteristics, chemotherapy sensitivity, and tumor mutation burden (TMB) were investigated. GSEA was utilized to delineate biological processes and pathways associated with IGF2BPs.

RESULTS

IGF2BP2 and IGF2BP3 expression were found to be upregulated in LUSC patients. IGF2BP2 mRNA levels were correlated with cancer immunity in both LUSC and LUAD patients. A higher frequency of gene mutations was observed in different IGF2BP1/2/3 expression groups in LUAD compared to LUSC. Meta-analyses revealed a significant negative correlation between overall survival (OS) and IGF2BP2/3 expression in LUAD patients but not in LUSC patients. GSEA indicated a positive association between VEGF and IGF2BP family genes in LUAD, while matrix metallopeptidase activity was inversely correlated with IGF2BP family genes in LUSC. Several chemotherapy drugs showed significantly lower IC50 values in high IGF2BP expression groups in both LUAD and LUSC.

CONCLUSION

Our findings indicated that IGF2BPs play different roles in LUAD and LUSC. This divergence highlights the need for tailored therapeutic strategies and prognostic tools, cognizant of the unique molecular profiles of LUAD and LUSC.

Overexpression of zinc finger DHHC-type containing 1 is associated with poor prognosis and cancer cell growth and metastasis in uterine corpus endometrial carcinoma

The zinc finger DHHC-type containing 1 (ZDHHC1) gene is implicated in the pathogenesis and progression of various malignant tumors, but its precise involvement in uterine corpus endometrial carcinoma (UCEC) remains unknown. Thus, this study investigated ZDHHC1 expression in UCEC using publicly available TCGA and Xena databases and elucidated the functions and mechanisms of the ZDHHC1 gene in UCEC progression using bioinformatics and in vitro experiments. The correlation between ZDHHC1 expression and prognosis, clinical features, immune cells, and RNA modifications of UCEC was evaluated using nomograms, correlation, ROC, and survival analyses. The impacts of ZDHHC1 overexpression on UCEC progression and mechanisms were explored with bioinformatics and in vitro experiments. Our study revealed that ZDHHC1 expression was significantly downregulated in UCEC and correlated with poor prognosis, cancer diagnosis, clinical stage, age, weight, body mass index, histological subtypes, residual tumor, tumor grade, and tumor invasion. Notably, Cox regression analysis and constructed nomograms showed that downregulated ZDHHC1 expression was a prognostic factor associated with poor prognosis in patients with UCEC. Conversely, above-normal ZDHHC1 expression inhibited the cell growth, cell cycle transition, migration, and invasion of UCEC cells, which may be related to the cell cycle, DNA replication, PI3K-AKT, and other pathways that promote tumor progression. Altered ZDHHC1 expression in UCEC was significantly associated with RNA modifications and the changes in cancer immune cell populations, such as CD56 bright NK cells, eosinophils, Th2 cells, and cell markers. In conclusion, considerably reduced ZDHHC1 expression in UCEC is associated with cancer cell growth, metastasis, poor prognosis, immune infiltration, and RNA modifications, revealing the promising potential of ZDHHC1 as a prognostic marker for UCEC.

METTL3 promotes the osteogenic differentiation of human periodontal ligament cells by increasing YAP activity via IGF2BP1 and YTHDF1-mediated m6A modification

AIMS

N6-Methyladenosine (m6A) has been confirmed to play a dynamic role in osteoporosis and bone metabolism. However, whether m6A is involved in the osteogenic differentiation of human periodontal ligament cells (hPDLCs) remains unclear. The present study aimed to verify the role of methyltransferase-like 3 (METTL3)-mediated m6A modification in the osteogenic differentiation of hPDLCs.

METHODS

The METTL3, Runx2, Osx, and YAP mRNA expression was determined by qPCR. METTL3, RUNX2, OSX, YTHDF1, YAP, IGF2BP1, and eIF3a protein expression was measured by Western blotting and immunofluorescence assays. The levels of m6A modification were evaluated by methylated RNA immunoprecipitation (MeRIP) and dot blot analyses. MeRIP-seq and RNA-seq were used to screen potential candidate genes. Nucleic acid and protein interactions were detected by immunoprecipitation. Alizarin red staining was used to evaluate the osteogenic differentiation of hPDLCs. Gene transcription and promoter activities were assessed by luciferase reporter assays (n ≥ 3).

RESULTS

The expression of METTL3 and m6A modifications increased synchronously with the osteogenic differentiation of hPDLCs (p = .0016). YAP was a candidate gene identified by MeRIP-seq and RNA-seq, and its mRNA and protein expression levels were simultaneously increased. METTL3 increased the m6A methylated IGF2BP1-mediated stability of YAP mRNA (p = .0037), which in turn promoted osteogenic differentiation (p = .0147). Furthermore, METTL3 increased the translation efficiency of YAP by recruiting YTHDF1 and eIF3a to the translation initiation complex (p = .0154), thereby promoting the osteogenic differentiation of hPDLCs (p = .0012).

CONCLUSION

Our study revealed that METTL3-initiated m6A mRNA methylation promotes osteogenic differentiation of hPDLCs by increasing IGF2BP1-mediated YAP mRNA stability and recruiting YTHDF1 and eIF3a to the translation initiation complex to increase YAP mRNA translation. Our findings reveal the mechanism of METTL3-mediated m6A modification during hPDLC osteogenesis, providing a potential therapeutic target for periodontitis and alveolar bone defects.

Ramifications of m6A Modification on ncRNAs in Cancer

N6-methyladenosine (m6A) is an RNA modification wherein the N6-position of adenosine is methylated. It is one of the most prevalent internal modifications of RNA and regulates various aspects of RNA metabolism. M6A is deposited by m6A methyltransferases, removed by m6A demethylases, and recognized by reader proteins, which modulate splicing, export, translation, and stability of the modified mRNA. Recent evidence suggests that various classes of non- coding RNAs (ncRNAs), including microRNAs (miRNAs), circular RNAs (circRNAs), and long con-coding RNAs (lncRNAs), are also targeted by this modification. Depending on the ncRNA species, m6A may affect the processing, stability, or localization of these molecules. The m6A- modified ncRNAs are implicated in a number of diseases, including cancer. In this review, the author summarizes the role of m6A modification in the regulation and functions of ncRNAs in tumor development. Moreover, the potential applications in cancer prognosis and therapeutics are discussed.

Dynamic RNA methylation modifications and their regulatory role in mammalian development and diseases

Among over 170 different types of chemical modifications on RNA nucleobases identified so far, RNA methylation is the major type of epitranscriptomic modifications existing on almost all types of RNAs, and has been demonstrated to participate in the entire process of RNA metabolism, including transcription, pre-mRNA alternative splicing and maturation, mRNA nucleus export, mRNA degradation and stabilization, mRNA translation. Attributing to the development of high-throughput detection technologies and the identification of both dynamic regulators and recognition proteins, mechanisms of RNA methylation modification in regulating the normal development of the organism as well as various disease occurrence and developmental abnormalities upon RNA methylation dysregulation have become increasingly clear. Here, we particularly focus on three types of RNA methylations: N6-methylcytosine (m6A), 5-methylcytosine (m5C), and N7-methyladenosine (m7G). We summarize the elements related to their dynamic installment and removal, specific binding proteins, and the development of high-throughput detection technologies. Then, for a comprehensive understanding of their biological significance, we also overview the latest knowledge on the underlying mechanisms and key roles of these three mRNA methylation modifications in gametogenesis, embryonic development, immune system development, as well as disease and tumor progression.

Novel DNA methylation-based epigenetic signatures in colorectal cancer from peripheral blood leukocytes

Colorectal cancer (CRC) is a multifactorial disease characterized by accumulation of multiple genetic and epigenetic alterations, transforming colonic epithelial cells into adenocarcinomas. Alteration of DNA methylation (DNAm) is a promising biomarker for predicting cancer risk and prognosis, but its role in CRC tumorigenesis is inconclusive. Notably, few DNAm studies have used pre-diagnostic peripheral blood (PB) DNA, causing difficulty in postulating the underlying biologic mechanism of CRC initiation. We conducted epigenome-wide association (EWA) scans in postmenopausal women from Women's Health Initiative (WHI) with their pre-diagnostic DNAm in PB leukocytes (PBLs) to prospectively evaluate CRC development. Our site-specific DNAm analyses across the genome adjusted for DNAm-age, leukocyte heterogeneities, as well as body mass index, diabetes, and insulin resistance. We validated 20 top EWA-CpGs in 2 independent CRC tissue datasets. Also, we detected differentially methylated regions (DMRs) associated with CRC, further mapped to transcriptomic profile, and finally conducted a Gene Set Enrichment Analysis. We detected multiple novel CpGs validated across WHI and tissue datasets. In particular, 2 CpGs (B4GALNT4cg10321339, SV2Bcg18144285) had the strongest effect on CRC risk. Results from our DMR scans contained MIR663cg06007966, which was also validated in EWA analyses. Also, we detected 1 methylome region in PEG10 of Chr7 shared across datasets. Our findings reflect both novel and well-established epigenomic and transcriptomic sites in CRC, warranting further functional validations. Our study contributes to better understanding of the complex interrelated mechanisms on the methylome underlying CRC tumorigenesis and suggests novel preventive DNAm-targets in PBLs for detecting at-risk individuals for CRC development.

The m6A reader IGF2BP2 promotes esophageal cell carcinoma progression by enhancing EIF4A1 translation

Esophageal squamous cell carcinoma (ESCC) is one of most prevalent cancers worldwide, especially in China. Lacking in depth mechanism study, effective targets and therapeutics are desperately needed in the clinic. RNA-binding proteins (RBPs) mediate the localization, stability, and translation of the target transcripts and fine-tune the physiological functions of the proteins encoded. Bioinformatics analysis revealed that IGF2BPs were highly expressed in ESCC tissues and at least participated in the regulation of cell proliferation of ESCC cells. Biological researches demonstrated that IGF2BP2 promoted the cell proliferation, migration and invasion of ESCC KYSE30 and KYSE450 cells. IGF2BP2 could bind to EIF4A1 mRNA by recognition of m6A sites and enhanced translation of EIF4A1. IGF2BPs, as m6A reader, IGF2BPs were oncogenic genes in ESCC by regulating the expression of EIF4A1 through m6A sites. IGF2BP2, EIF4A1 and their targets could serve as potential biomarkers and therapeutic targets for ESCC, offering promising novel approaches for the diagnosis and treatment of ESCC.

N6-Methyladenosine reader HNRNPC-mediated downregulation of circITCH prevents miR-224-3p sequestering and contributes to tumorigenesis in nasopharyngeal carcinoma

BACKGROUND

N6-Methyladenosine (m6A) RNA methylation modulators are implicated in nasopharyngeal carcinoma (NPC). Circular RNAs (circRNAs) stimulate/inhibit the development of NPC by sponging microRNAs (miRNAs). Herein, m6A modifications affecting the circRNA/miRNA axis in NPC were explored.

METHODS

Twenty prognostic m6A RNA methylation regulators were identified from 504 head/neck squamous cell carcinoma and 44 normal samples from The Cancer Genome Atlas (TCGA). Differentially expressed miRNAs were screened from the TCGA and Gene Expression Omnibus (GEO) databases. RNA-binding protein (RBP)-circRNA and circRNA-miRNA interactive pairs were verified using RBPmap and RNAhybrid, respectively. The RBP/circRNA/miRNA network was constructed using Cytoscape. Furthermore, CircITCH (hsa_circ_00059948), HNRNPC, and miR-224-3p expressions were detected by western blotting and quantitative polymerase chain reaction. The role of circITCH in NPC was examined using apoptosis, scratch wound healing, transwell invasion, and cell counting kit-8 assays. Finally, CircITCH-miR-224-3p and circITCH-HNRNPC interactions were assessed by dual-luciferase reporter and RNA-immunoprecipitation (RIP) assays, respectively.

RESULTS

Bioinformatics analysis revealed that high pathological grade, late-stage tumors, and low survival were associated with increased HNRNPC expression. MiR-224-3p was upregulated in NPC and sequestered by circITCH. Construction of the RBP/circRNA/miRNA network highlighted the HNRNPC/circITCH/miR-224-3p axis. In vitro experiments demonstrated decreased circITCH expression and increased HNRNPC and miR-224-3p expressions in NPC. In NPC cells overexpressing circITCH, HNRNPC and miR-224-3p expressions were significantly decreased. Dual-luciferase assays demonstrated a targeting relationship between circITCH and miR-224-3p, and RIP assays demonstrated interaction of HNRNPC targets with circITCH.

CONCLUSION

CircITCH overexpression inhibited NPC progression by sequestering miR-224-3p, and HNRNPC reduced circITCH expression through direct interaction.

Abrogation of USP9X Is a Potential Strategy to Decrease PEG10 Levels and Impede Tumor Progression in Cutaneous T-Cell Lymphoma

Advanced-stage cutaneous T-cell lymphomas (CTCLs) are notorious for their highly aggressive behavior, resistance to conventional treatments, and poor prognosis, particularly when large-cell transformation occurs. PEG10 has been recently proposed as a potent driver for large-cell transformation in CTCL. However, the targeting of PEG10 continues to present a formidable clinical challenge that has yet to be addressed. In this study, we report an important post-translational regulatory mechanism of PEG10 in CTCL. USP9X, a deubiquitinase, interacted with and deubiquitinated PEG10, thereby stabilizing PEG10. Knockdown of USP9X or pharmacological targeting of USP9X resulted in a prominent downregulation of PEG10 and its downstream pathway in CTCL. Moreover, USP9X inhibition conferred tumor cell growth disadvantage and enhanced apoptosis in vitro, an effect that occurred in part through its regulation on PEG10. Furthermore, we demonstrated that inhibition of USP9X obviously restrained CTCL tumor growth in vivo and that high expression of USP9X is associated with poor survival in patients with CTCL. Collectively, our findings uncover USP9X as a key post-translational regulator in the stabilization of PEG10 and suggest that targeting PEG10 stabilization through USP9X inhibition may represent a promising therapeutic strategy for advanced-stage CTCL.

A comprehensive review of m6A research in cervical cancer

Cervical cancer (CC) remains one of the most common malignancies among women worldwide, posing a serious threat to women's health. N6-methyladenosine (m6A) modification, as the most abundant type of RNA methylation modification, and has been found to play a crucial role in various cancers. Current research suggests a close association between RNA m6A modification and the occurrence and progression of CC, encompassing disruptions in m6A levels and its regulatory machinery. This review summarizes the current status of m6A modification research in CC, explores the mechanisms underlying m6A levels and regulators (methyltransferases, demethylases, reader proteins) in CC and examines the application of small-molecule inhibitors of m6A regulators in disease treatment. The findings provide new insights into the future treatment of CC.

N6-methyladenosine reader protein IGF2BP1 suppresses CD8 + T cells-mediated tumor cytotoxicity and apoptosis in colon cancer

Tumor immune escape is an important manner for colon cancer to escape effective killing by immune system. Currently, the immune checkpoint PD-1/PD-L1-targeted immunotherapy has emerged as a promising therapeutic strategy in colon cancer. Here, present work aims to investigate the biological function of N6-methyladenosine (m6A) reader insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) in regulating colon cancer's immune escape and CD8 + T cells-mediated tumor cytotoxicity and apoptosis. Results illustrated that IGF2BP1 was closely correlated to the colon cancer patients' poor clinical outcome. Functionally, upregulation of IGF2BP1 suppressed the CD8+ T-cells mediated antitumor immunity through reducing their tumor cytotoxicity. Mechanistically, MeRIP-Seq revealed that programmed death ligand 1 (PD-L1) mRNA had a remarkable m6A modified site on 3'-UTR genomic. Moreover, PD-L1 acted as the target of IGF2BP1, which enhanced the stability of PD-L1 mRNA. Overall, these results indicated that IGF2BP1 targeted PD-L1 to accelerate the immune escape in colon cancer by reducing CD8 + T cells-mediated tumor cytotoxicity in m6A-dependent manner. The findings demonstrate the potential of m6A-targeted immune checkpoint blockade in colon cancer, providing a novel insight for colon cancer immune escape and antitumor immunity in further precise treatment.

N6-methyladenosine demethyltransferase FTO mediated m6A modification of estrogen receptor alpha in non-small cell lung cancer tumorigenesis

Fat mass and obesity-associated protein (FTO), which is closely linked with obesity and dietary intake, plays an important role in diet-related metabolic diseases. However, the underlying mechanism of the N6-methyladenosine (m6A) demethyltransferase FTO in tumor development and progression remains largely unexplored. Here, we demonstrated that FTO expression was largely lower in non-small cell lung cancer (NSCLC) samples than in adjacent healthy tissues, and its expression negatively correlated with poor prognosis. Gain- and loss-of-function assays revealed that FTO inhibited NSCLC tumor cell growth and metastasis in vitro and in vivo. Mechanistically, estrogen receptor alpha (ESR1) is a target of FTO, and increased FTO expression significantly impaired the m6A levels of ESR1 mRNA. There were two clear m6A modification sites (5247A and 5409A) in the 3' untranslated region (3'UTR) of ESR1, and FTO could decrease their methylation. Moreover, the m6A readers YTHDF1 and IGF2BP3 recognized and bound the m6A sites in ESR1 mRNA, thereby enhancing its stability and facilitating tumor growth. We also showed that ESR1 has good diagnostic value for NSCLC. In conclusion, we uncovered an important mechanism of epitranscriptomic regulation by the FTO-YTHDF1-IGF2BP3-ESR1 axis and identified the potential of m6A-dependent therapeutic strategies for NSCLC.

FTO-mediated autophagy inhibition promotes non-small cell lung cancer progression by reducing the stability of SESN2 mRNA

The role of fat mass and obesity-associated protein (FTO), an N6-methyladenosine (m6A) demethylase, in non-small cell lung cancer (NSCLC) has recently received widespread attention. However the underlying mechanisms of FTO-mediated autophagy regulation in NSCLC progression remain elusive. In this study, we found that FTO was significantly upregulated in NSCLC, and downregulation of FTO suppressed the growth, invasion and migration of NSCLC cells by inducing autophagy. FTO knockdown resulted in elevated m6A levels in NSCLC cells. Methylated RNA immunoprecipitation sequencing showed that sestrin 2 (SESN2) was involved in m6A regulation during autophagy in NSCLC cells. Interestingly, m6A modifications in exon 9 of SESN2 regulated its stability. FTO deficiency promoted the binding of insulin-like growth factor 2 mRNA-binding protein 1 to SESN2 mRNA, enhancing its stability and elevating its protein expression. FTO inhibited autophagic flux by downregulating SESN2, thereby promoting the growth, invasion and migration of NSCLC cells. Besides, the mechanism by which FTO blocked SESN2-mediated autophagy activation was associated with the AMPK-mTOR signaling pathway. Taken together, these findings uncover an essential role of the FTO-autophagy-SESN2 axis in NSCLC progression.

IGF2BPs as novel m6A readers: Diverse roles in regulating cancer cell biological functions, hypoxia adaptation, metabolism, and immunosuppressive tumor microenvironment

m6A methylation is the most frequent modification of mRNA in eukaryotes and plays a crucial role in cancer progression by regulating biological functions. Insulin-like growth factor 2 mRNA-binding proteins (IGF2BP) are newly identified m6A 'readers'. They belong to a family of RNA-binding proteins, which bind to the m6A sites on different RNA sequences and stabilize them to promote cancer progression. In this review, we summarize the mechanisms by which different upstream factors regulate IGF2BP in cancer. The current literature analyzed here reveals that the IGF2BP family proteins promote cancer cell proliferation, survival, and chemoresistance, inhibit apoptosis, and are also associated with cancer glycolysis, angiogenesis, and the immune response in the tumor microenvironment. Therefore, with the discovery of their role as 'readers' of m6A and the characteristic re-expression of IGF2BPs in cancers, it is important to elucidate their mechanism of action in the immunosuppressive tumor microenvironment. We also describe in detail the regulatory and interaction network of the IGF2BP family in downstream target RNAs and discuss their potential clinical applications as diagnostic and prognostic markers, as well as recent advances in IGF2BP biology and associated therapeutic value.

Decoding m6A mRNA methylation by reader proteins in liver diseases

N6-methyladenosine (m6A) is a dynamic and reversible epigenetic regulation. As the most prevalent internal post-transcriptional modification in eukaryotic RNA, it participates in the regulation of gene expression through various mechanisms, such as mRNA splicing, nuclear export, localization, translation efficiency, mRNA stability, and structural transformation. The involvement of m6A in the regulation of gene expression depends on the specific recognition of m6A-modified RNA by reader proteins. In the pathogenesis and treatment of liver disease, studies have found that the expression levels of key genes that promote or inhibit the development of liver disease are regulated by m6A modification, in which abnormal expression of reader proteins determines the fate of these gene transcripts. In this review, we introduce m6A readers, summarize the recognition and regulatory mechanisms of m6A readers on mRNA, and focus on the biological functions and mechanisms of m6A readers in liver cancer, viral hepatitis, non-alcoholic fatty liver disease (NAFLD), hepatic fibrosis (HF), acute liver injury (ALI), and other liver diseases. This information is expected to be of high value to researchers deciphering the links between m6A readers and human liver diseases.

Knowledge mapping and current trends of m6A methylation in the field of cancer

Background

Cancer is a serious threat to people's lives and health, killing millions of people every year. Here, we performed a bibliometric analysis of tumor N6-methyladenosine methylation data between 2001 and 2022 to understand research trends and potential future directions.

Methods

A total of 890 papers published in the Web of Science core collection database between January 1, 2001 and December 31, 2022 were analyzed. Bibliometric analysis was performed using VOSviewer software to explore citations, co-authorship, co-citations, and co-occurrence.

Results

Although few papers were published before 2018, there was a rapid increase in publications after 2018. The People's Republic of China published 810 papers with 16,957 citations, both ranking first in the word. Sun Yat Sen University had the highest number of citations and published articles (67 published papers and 2702 citations), indicative of its active collaborative research status. Wang Xiao was the most co-cited author with 546 co-citations. Huang Yufei and Meng Jia ranked first with a link strength of 22, making them the most active collaborative authors. Frontiers in Oncology and Nature were the most active and co-cited journals, with 57 papers and 1953 co-citations, respectively. Studies of tumor N6-methyladenosine methylation can be divided into three categories: "tumor metabolism", "tumor bioinformatics and immunity", and "tumor progression".

Conclusions

This study systematically summarized the research on tumor N6-methyladenosine methylation during the past 20 years and suggested potential ways to explore its biomarkers and immunotherapy in the future.

LINC00858 facilitates formation of hepatic metastases from colorectal cancer via regulating the miR-132-3p/IGF2BP1 axis

Hepatic metastasis is a major cause of colorectal cancer (CRC)-related deaths. Presently, the role of long non-coding RNAs (lncRNAs) in hepatic metastases from CRC is elusive. We dissected possible interplay between LINC00858/miR-132-3p/IGF2BP1 via bioinformatics approaches. Subsequently we analyzed mRNA expression of LINC00858, miR-132-3p and IGF2BP1 through qRT-PCR. Western blot was used to detect protein expression of IGF2BP1. RNA immunoprecipitation chip and dual-luciferase assay validated interaction between LINC00858 and miR-132-3p, as well as miR-132-3p and IGF2BP1. Cell viability, invasion, and migration were examined via CCK-8, colony formation, transwell and wound healing assays. Effect of LINC00858 on CRC hepatic metastases was validated via in vivo assay. Upregulated LINC00858 and IGF2BP1, and downregulated miR-132-3p were predicted in tumor tissues of patients with hepatic metastases from CRC. There were targeting relationships between LINC00858 and miR-132-3p, as well as miR-132-3p and IGF2BP1. Besides, LINC00858 facilitated progression of CRC cells. Rescue assay suggested that silencing LINC00858 suppressed CRC cell progression, while further silencing miR-132-3p or overexpressing IGF2BP1 reversed such effects. LINC00858 could facilitate CRC tumor growth and hepatic metastases. LINC00858 induced CRC hepatic metastases via regulating miR-132-3p/ IGF2BP1, and this study may deliver a new diagnostic marker for the disease.

Multigenerational paternal obesity enhances the susceptibility to male subfertility in offspring via Wt1 N6-methyladenosine modification

There is strong evidence that obesity is a risk factor for poor semen quality. However, the effects of multigenerational paternal obesity on the susceptibility to cadmium (a reproductive toxicant)-induced spermatogenesis disorders in offspring remain unknown. Here, we show that, in mice, spermatogenesis and retinoic acid levels become progressively lower as the number of generations exposed to a high-fat diet increase. Furthermore, exposing several generations of mice to a high fat diet results in a decrease in the expression of Wt1, a transcription factor upstream of the enzymes that synthesize retinoic acid. These effects can be rescued by injecting adeno-associated virus 9-Wt1 into the mouse testes of the offspring. Additionally, multigenerational paternal high-fat diet progressively increases METTL3 and Wt1 N6-methyladenosine levels in the testes of offspring mice. Mechanistically, treating the fathers with STM2457, a METTL3 inhibitor, restores obesity-reduced sperm count, and decreases Wt1 N6-methyladenosine level in the mouse testes of the offspring. A case-controlled study shows that human donors who are overweight or obese exhibit elevated N6-methyladenosine levels in sperm and decreased sperm concentration. Collectively, these results indicate that multigenerational paternal obesity enhances the susceptibility of the offspring to spermatogenesis disorders by increasing METTL3-mediated Wt1 N6-methyladenosine modification.

METTL3 Promotes Osteogenic Differentiation of Human Periodontal Ligament Stem Cells through IGF2BP1-Mediated Regulation of Runx2 Stability

N6-Methyladenosine (m6A) has been reported to play a dynamic role in osteoporosis and bone metabolism. However, whether m6A is involved in the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) remains unclear. Here, we found that methyltransferase-like 3 (METTL3) was up-regulated synchronously with m6A during the osteogenic differentiation of hPDLSCs. Functionally, lentivirus-mediated knockdown of METTL3 in hPDLSCs impaired osteogenic potential. Mechanistic analysis further showed that METTL3 knockdown decreased m6A methylation and reduced IGF2BP1-mediated stability of runt-related transcription factor 2 (Runx2) mRNA, which in turn inhibited osteogenic differentiation. Therefore, METTL3-based m6A modification favored osteogenic differentiation of hPDLSCs through IGF2BP1-mediated Runx2 mRNA stability. Our study shed light on the critical roles of m6A on regulation of osteogenic differentiation in hPDLSCs and served novel therapeutic approaches in vital periodontitis therapy.

Construction of a Lung Adenocarcinoma Prognostic Model Utilizing Serine and Glycine Metabolism-Related Genes

The objective of this study was to construct a prognostic model by utilizing serine/glycine metabolism-related genes (SGMGs), thus establishing a risk score for lung adenocarcinoma (LUAD). Based on the TCGA-LUAD and SGMG data set, two subtypes with different SGMG expression levels were identified by clustering analysis. Thirteen differential expression genes were used to construct RiskScore by Cox regression. GSE72094 data set was used for validation. The survival characteristics, immune features, and potential benefits of chemotherapy drugs were analyzed for two risk groups. RiskScore was constructed based on the genes ABCC12, RIC3, CYP4B1, SFTPB, CACNA2D2, IGF2BP1, NTSR1, DKK1, CREG2, PITX3, RGS20, FETUB, and IGFBP1. Patients in the low-risk (LR) group exhibited a superior overall survival. In addition, aDCs, iDSs, mast cells, neutrophils, HLA, and type II IFN were more abundant in the LR group with higher IPS scores and lower TIDE scores. In contrast, NK cells, APC coinhibition, and MHC-I were more common in the high-risk (HR) group, which may be more sensitive to chemotherapy drugs such as cisplatin, oxaliplatin, and nilotinib. RiskScore was a promising biomarker that can be used to distinguish LUAD prognosis, immune features, and sensitivity to chemotherapy drugs.

LRPPRC promotes glycolysis by stabilising LDHA mRNA and its knockdown plus glutamine inhibitor induces synthetic lethality via m6 A modification in triple-negative breast cancer

BACKGROUND

Targeted therapy for triple-negative breast cancer (TNBC) remains a challenge. N6-methyladenosine (m6 A) is the most abundant internal mRNA modification in eukaryotes, and it regulates the homeostasis and function of modified RNA transcripts in cancer. However, the role of leucine-rich pentatricopeptide repeat containing protein (LRPPRC) as an m6 A reader in TNBC remains poorly understood.

METHODS

Western blotting, reverse transcription-polymerase chain reaction (RT-qPCR) and immunohistochemistry were used to investigate LRPPRC expression levels. Dot blotting and colorimetric enzyme linked immunosorbent assay (ELISA) were employed to detect m6 A levels. In vitro functional assays and in vivo xenograft mouse model were utilised to examine the role of LRPPRC in TNBC progression. Liquid chromatography-mass spectrometry/mass spectrometry and Seahorse assays were conducted to verify the effect of LRPPRC on glycolysis. MeRIP-sequencing, RNA-sequencing, MeRIP assays, RNA immunoprecipitation assays, RNA pull-down assays and RNA stability assays were used to identify the target genes of LRPPRC. Patient-derived xenografts and organoids were employed to substantiate the synthetic lethality induced by LRPPRC knockdown plus glutaminase inhibition.

RESULTS

The expressions of LRPPRC and m6 A RNA were elevated in TNBC, and the m6 A modification site could be recognised by LRPPRC. LRPPRC promoted the proliferation, metastasis and glycolysis of TNBC cells both in vivo and in vitro. We identified lactate dehydrogenase A (LDHA) as a novel direct target of LRPPRC, which recognised the m6 A site of LDHA mRNA and enhanced the stability of LDHA mRNA to promote glycolysis. Furthermore, while LRPPRC knockdown reduced glycolysis, glutaminolysis was enhanced. Moreover, the effect of LRPPRC on WD40 repeat domain-containing protein 76 (WDR76) mRNA stability was impaired in an m6 A-dependent manner. Then, LRPPRC knockdown plus a glutaminase inhibition led to synthetic lethality.

CONCLUSIONS

Our study demonstrated that LRPPRC promoted TNBC progression by regulating metabolic reprogramming via m6 A modification. These characteristics shed light on the novel combination targeted therapy strategies to combat TNBC.

Long non-coding RNA linc00659 promotes tumour progression by regulating FZD6/Wnt/β-catenin signalling pathway in colorectal cancer via m6A reader IGF2BP1

BACKGROUND

Abnormal N6-methyladenosine (m6A) modification has become a driving factor in tumour development and progression. The linc00659 is abnormally highly expressed in digestive tract tumours and promotes cancer progression, but there is little research on the mechanism of linc00659 and m6A.

METHODS

The expression of linc00659 in colorectal cancer (CRC) tissues and cells was assessed by a quantitative real-time PCR. The proliferative capacity of CRC cells was determined by colony formation, Cell Counting Kit-8 and 5-ethynyl-2 deoxyuridine assays, and the migratory capacity of CRC was determined by wound healing and transwell assays and tube formation. In vivo, a xenograft tumour model was used to detect the effect of linc00659 on tumour growth. The Wnt/β-catenin signalling pathway and related protein expression levels were measured by western blotting. The binding of linc00659 to insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) was assessed by RNA pull-down and an immunoprecipitation assay. The effect of IGF2BP1 on FZD6 was detected by an RNA stability assay.

RESULTS

The expression of linc00659 was abnormally elevated in CRC tissues and cells compared to normal colonic tissues and cells. We confirm that linc00659 promotes the growth of CRC cells both in vivo and in vitro. Mechanistically, linc00659 binds to IGF2BP1 and specifically enhances its activity to stabilize the target gene FZD6. Therefore, linc00659 and IGF2BP1 activate the Wnt/β-catenin signalling pathway, promoting cell proliferation in CRC.

CONCLUSIONS

Our results show that linc00659 and IGF2BP1 cooperate to promote the stability of the target FZD6 mRNA, thereby facilitating CRC progression, which may represent a potential diagnostic, prognostic and therapeutic target for CRC.

IGF2BP1 enhances the stability of SIK2 mRNA through m6A modification to promote non-small cell lung cancer progression

BACKGROUND

Non-small cell lung cancer (NSCLC) is a significant public health concern globally. Evidence suggests that Salt-inducible kinase 2 (SIK2) is differentially expressed across various cancers and is also implicated in cancer progression. Despite this, the precise function of SIK2 in NSCLC is yet to be elucidated and requires further investigation.

METHODS

SIK2 expression was evaluated in both HBEC and NSCLC cells, utilizing quantitative real-time PCR (qRT-PCR) and Western blot (WB) analyses. Furthermore, to identify the influence of SIK2 on cell proliferation, migration, invasion, and apoptosis, a range of techniques were employed. To evaluate N6-methyladenosine (m6A) modification levels of total RNA and SIK2 within cells, RNA m6A colorimetry and methylated RNA immunoprecipitation (MeRIP) techniques were employed. Additionally, to confirm the interaction between SIK2 and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), bioinformatics analysis was executed, and the results were validated through RIP. The stability of SIK2 mRNA was determined using actinomycin D experiment. Furthermore, to validate the in vivo functionality of SIK2, a subcutaneous transplantation tumor model was established in nude mice.

RESULTS

In this study, upregulation of SIK2 in NSCLC cells was observed. Overexpression of SIK2 was found to lead to promotion of cell proliferation, migration, invasion, and suppression of the Hippo/yes-associated protein (YAP) pathway, while inhibiting apoptosis. RIP analysis showed that IGF2BP1 protein interacted with SIK2 mRNA. Knockdown of IGF2BP1 decreased mRNA stability and m6A modification levels of SIK2. Additionally, knockdown of IGF2BP1 resulted in inhibition of cell proliferation, migration, invasion, suppression of the Hippo/YAP pathway, and promoting apoptosis. Overexpression of SIK2 overturned the impact of IGF2BP1 on NSCLC cells, which was then confirmed through in vivo experiments.

CONCLUSION

IGF2BP1 stabilized SIK2 mRNA through m6A modification to promote NSCLC progression, potentially offering new diagnostic and therapeutic insights for NSCLC.

Targeting PEG10 as a novel therapeutic approach to overcome CDK4/6 inhibitor resistance in breast cancer

BACKGROUND

Breast cancer is the global leading cancer burden in women and the hormone receptor-positive (HR+) subtype is a major part of breast cancer. Though cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors are highly effective therapy for HR+ subtype, acquired resistance is inevitable in most cases. Herein, we investigated the paternally expressed gene 10 (PEG10)-associated mechanism of acquired resistance to CDK4/6 inhibitors.

METHODS

Palbociclib-resistant cells were generated by exposing human HR+ breast cancer cell lines to palbociclib for 7-9 months. In vitro mechanistic study and in vivo xenograft assay were performed. For clinical relevance, public mRNA microarray data sets of early breast cancer were analyzed and PEG10 immunohistochemical staining was performed using pre-CDK4/6 inhibitor tumor samples.

RESULTS

We observed that PEG10 was significantly upregulated in palbociclib-resistant cells. Ectopic overexpression of PEG10 in parental cells caused CDK4/6 inhibitor resistance and enhanced epithelial-mesenchymal transition (EMT). On the contrary, PEG10-targeting siRNA or antisense oligonucleotides (ASOs) combined with palbociclib synergistically inhibited proliferation of palbociclib-resistant cells and growth of palbociclib-resistant xenograft in mice and suppressed EMT as well. The mechanistic study confirmed that high PEG10 expression suppressed p21, a natural CDK inhibitor, and SIAH1, a post-translational degrader of ZEB1, augmenting CDK4/6 inhibitor resistance. Then PEG10 siRNA combined with palbociclib suppressed cell cycle progression and EMT via activating p21 and SIAH1, respectively. Consequently, combined PEG10 inhibition and palbociclib overcame CDK4/6 inhibitor resistance. Furthermore, high PEG10 expression was significantly associated with a shorter recurrence-free survival (RFS) based on public mRNA expression data. In pre-CDK4/6 inhibitor treatment tissues, PEG10 positivity by IHC also showed a trend toward a shorter progression-free survival (PFS) with CDK4/6 inhibitor. These results support clinical relevance of PEG10 as a therapeutic target.

CONCLUSIONS

We demonstrated a novel PEG10-associated mechanism of CDK4/6 inhibitor resistance. We propose PEG10 as a promising therapeutic target for overcoming PEG10-associated resistance to CDK4/6 inhibitors.

N6-methyladenosine-modified circRIMS2 mediates synaptic and memory impairments by activating GluN2B ubiquitination in Alzheimer's disease

BACKGROUND

Synaptic degeneration occurs in the early stage of Alzheimer's disease (AD) before devastating symptoms, strongly correlated with cognitive decline. Circular RNAs (circRNAs) are abundantly enriched in neural tissues, and aberrant expression of circRNAs precedes AD symptoms, significantly correlated with clinical dementia severity. However, the direct relationship between circRNA dysregulation and synaptic impairment in the early stage of AD remains poorly understood.

METHODS

Hippocampal whole-transcriptome sequencing was performed to identify dysregulated circRNAs and miRNAs in 4-month-old wild-type and APP/PS1 mice. RNA antisense purification and mass spectrometry were utilized to unveil interactions between circRIMS2 and methyltransferase 3, N6-adenosine-methyltransferase complex catalytic subunit (METTL3). The roles of circRIMS2/miR-3968 in synaptic targeting of UBE2K-mediated ubiquitination of GluN2B subunit of NMDA receptor were evaluated via numerous lentiviruses followed by morphological staining, co-immunoprecipitation and behavioral testing. Further, a membrane-permeable peptide was used to block the ubiquitination of K1082 on GluN2B in AD mice.

RESULTS

circRIMS2 was significantly upregulated in 4-month-old APP/PS1 mice, which was mediated by METTL3-dependent N6-methyladenosine (m6A) modification. Overexpression of circRIMS2 led to synaptic and memory impairments in 4-month-old C57BL/6 mice. MiR-3968/UBE2K was validated as the downstream of circRIMS2. Elevated UBE2K induced synaptic dysfunction of AD through ubiquitinating K1082 on GluN2B. Silencing METTL3 or blocking the ubiquitination of K1082 on GluN2B with a short membrane-permeable peptide remarkably rescued synaptic dysfunction in AD mice.

CONCLUSIONS

In conclusion, our study demonstrated that m6A-modified circRIMS2 mediates the synaptic and memory impairments in AD by activating the UBE2K-dependent ubiquitination and degradation of GluN2B via sponging miR-3968, providing novel therapeutic strategies for AD.

The role of m6A RNA methylation regulator in meningioma

Meningiomas are common intracranial tumors, and the effect of surgical resection is often unsatisfactory. N6-Methyladenosine (m6A)-related regulator expression levels are related to cancer occurrence and development. This study aimed to investigate the roles of m6A RNA methylation regulators in meningiomas, as these are currently unclear. Two m6A methylation-regulated genes (METTL3 and IGF2BP2) were identified as survival-associated linear models for RiskScore through bioinformatics analysis. Univariate and multivariate Cox regression analyses showed that the overall survival of patients with meningioma in the high-risk group was substantially shorter than that in the low-risk group. Weighted gene co-expression network analysis constructed a co-expression network based on the m6A methylation model (RiskScore). Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes analyses identified the biological processes of hub module gene behavior, and Cytoscape constructed an m6A methylation-related gene regulatory network. In vitro experiments verified that the mRNA and protein expression levels of METTL3 and IGF2BP2 were lower in meningioma cells than in normal meningioma cells. Therefore, central regulators of m6A methylation (METTL3 and IGF2BP2) could potentially serve as novel therapeutic targets in meningioma. Subsequently, a novel methylation signature (RiskScore) was developed for prognostic prediction in patients with meningioma.

The emerging role of m6A modification of non-coding RNA in gastrointestinal cancers: a comprehensive review

Gastrointestinal (GI) cancer is a series of malignant tumors with a high incidence globally. Although approaches for tumor diagnosis and therapy have advanced substantially, the mechanisms underlying the occurrence and progression of GI cancer are still unclear. Increasing evidence supports an important role for N6-methyladenosine (m6A) modification in many biological processes, including cancer-related processes via splicing, export, degradation, and translation of mRNAs. Under distinct cancer contexts, m6A regulators have different expression patterns and can regulate or be regulated by mRNAs and non-coding RNAs, especially long non-coding RNAs. The roles of m6A in cancer development have attracted increasing attention in epigenetics research. In this review, we synthesize progress in our understanding of m6A and its roles in GI cancer, especially esophageal, gastric, and colorectal cancers. Furthermore, we clarify the mechanism by which m6A contributes to GI cancer, providing a basis for the development of diagnostic, prognostic, and therapeutic targets.

Shining a spotlight on m6A and the vital role of RNA modification in endometrial cancer: a review

RNA modifications are mostly dynamically reversible post-transcriptional modifications, of which m6A is the most prevalent in eukaryotic mRNAs. A growing number of studies indicate that RNA modification can finely tune gene expression and modulate RNA metabolic homeostasis, which in turn affects the self-renewal, proliferation, apoptosis, migration, and invasion of tumor cells. Endometrial carcinoma (EC) is the most common gynecologic tumor in developed countries. Although it can be diagnosed early in the onset and have a preferable prognosis, some cases might develop and become metastatic or recurrent, with a worse prognosis. Fortunately, immunotherapy and targeted therapy are promising methods of treating endometrial cancer patients. Gene modifications may also contribute to these treatments, as is especially the case with recent developments of new targeted therapeutic genes and diagnostic biomarkers for EC, even though current findings on the relationship between RNA modification and EC are still very limited, especially m6A. For example, what is the elaborate mechanism by which RNA modification affects EC progression? Taking m6A modification as an example, what is the conversion mode of methylation and demethylation for RNAs, and how to achieve selective recognition of specific RNA? Understanding how they cope with various stimuli as part of in vivo and in vitro biological development, disease or tumor occurrence and development, and other processes is valuable and RNA modifications provide a distinctive insight into genetic information. The roles of these processes in coping with various stimuli, biological development, disease, or tumor development in vivo and in vitro are self-evident and may become a new direction for cancer in the future. In this review, we summarize the category, characteristics, and therapeutic precis of RNA modification, m6A in particular, with the purpose of seeking the systematic regulation axis related to RNA modification to provide a better solution for the treatment of EC.

N6-Methyladenosine (m6A) Reader IGF2BP1 Accelerates Gastric Cancer Development and Immune Escape by Targeting PD-L1

N6-methyladenosine (m6A) functions as an important regulator in various human cancers, including gastric cancer. The immunotherapy targeting PD-1/PD-L1 has brought hope for advanced gastric cancer therapeutic. Here, present research aims to investigate the roles of m6A reader IGF2BP1 on gastric cancer tumor development and immune escape. Results indicated that IGF2BP1 up-regulated in the gastric cancer tissue and correlated with poor prognosis of gastric cancer patients. IGF2BP1 overexpression augmented the proliferation of co-cultured gastric cancer cells, and mitigated the CD8+ T cells mediated anti-tumor response, including IFN-γ secretion, surface PD-L1 level, and cytotoxicity of CD8+ T cells. Meanwhile, IGF2BP1 silencing exerted the opposite effects. In silico analysis revealed that there was a remarkable m6A modified site on PD-L1 mRNA. Moreover, the IGF2BP1 overexpression enhanced the stability of PD-L1 mRNA, thereby deteriorating the immune escape of gastric cancer cells. Collectively, these results describe a novel regulatory mechanism of IGF2BP1 by regulating PD-L1 through m6A epigenetic modification, which might provide insights for gastric cancer immunotherapies.

LncRNA FEZF1-AS1 accelerates multiple myeloma progression by regulating IGF2BP1/BZW2 signaling

Multiple myeloma (MM) is the second largest hematological tumor with clonal proliferation of malignant plasma cells. Growing reports have revealed that the dysregulation of long non-coding RNA (lncRNA) is involved in the MM progression. Nevertheless, lncRNA FEZF1 antisense RNA 1 (FEZF1-AS1) remain not deeply explored. The RNA transcripts and protein level of MM-associated molecule were measured by quantitative real-time polymerase chain reaction or western blot assays, respectively. The clinical correlation was analyzed by Pearson analysis. Molecular interactions among lncRNA FEZF1-AS1, basic leucine zipper and W2 domain 2 (BZW2) and insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) were verified by RNA immunoprecipitation and RNA pull-down assays. The survival of MM cells was detected by cell counting kit-8 and flow cytometry assays. Xenograft tumor in vivo was performed to assess tumor growth. The RNA transcripts of lncRNA FEZF1-AS1, BZW2 and IGF2BP1 were upregulated in MM samples compared to those in healthy donors. Knockdown of lncRNA FEZF1-AS1 could inhibit the proliferation and induce cell apoptosis in vitro and in vivo. Besides, lncRNA FEZF1-AS1 could maintain the stability of BZW2 mRNA by interacting IGF2BP1. Moreover, BZW2 silence also downregulated the proliferation but enhanced apoptosis of MM cells, while BZW2 overexpression had an opposite role, which dramatically reversed the regulatory roles of lncRNA FEZF1-AS1. Altogether, lncRNA FEZF1-AS1 facilitated MM development by regulating IGF2BP1/BZW2 signaling, suggesting that lncRNA FEZF1-AS1 might be a candidate for MM treatment.

Sperm Rhoa m6A modification mediates intergenerational transmission of paternally acquired hippocampal neuronal senescence and cognitive deficits after combined exposure to environmental cadmium and high-fat diet in mice

Little is currently known about the effect and mechanism of combined paternal environmental cadmium (Cd) and high-fat diet (HFD) on offspring cognitive ability. Here, using in vivo model, we found that combined paternal environmental Cd and HFD caused hippocampal neuronal senescence and cognitive deficits in offspring. MeRIP-seq revealed m6A level of Rhoa, a regulatory gene of cellular senescence, was significantly increased in combined environmental Cd and HFD-treated paternal sperm. Interestingly, combined paternal environmental Cd and HFD markedly enhanced Rhoa mRNA, its m6A and reader protein IGF2BP1 in offspring hippocampus. STM2457, the inhibitor of m6A modification, markedly mitigated paternal exposure-caused the elevation of hippocampal Rhoa m6A, neuronal senescence and cognitive deficits in offspring. In vitro experiments, Rhoa siR significantly reversed mouse hippocampal neuronal senescence. Igf2bp1 siR obviously reduced the level and stability of Rhoa in aging mouse hippocampal neuronal cells. In conclusion, combined paternal environmental Cd and HFD induce offspring hippocampal neuronal senescence and cognitive deficits by promoting IGF2BP1-mediated Rhoa stabilization in offspring hippocampus via elevating Rhoa m6A in paternal sperm.

New insights for gynecological cancer therapies: from molecular mechanisms and clinical evidence to future directions

Advanced and recurrent gynecological cancers lack effective treatment and have poor prognosis. Besides, there is urgent need for conservative treatment for fertility protection of young patients. Therefore, continued efforts are needed to further define underlying therapeutic targets and explore novel targeted strategies. Considerable advancements have been made with new insights into molecular mechanisms on cancer progression and breakthroughs in novel treatment strategies. Herein, we review the research that holds unique novelty and potential translational power to alter the current landscape of gynecological cancers and improve effective treatments. We outline the advent of promising therapies with their targeted biomolecules, including hormone receptor-targeted agents, inhibitors targeting epigenetic regulators, antiangiogenic agents, inhibitors of abnormal signaling pathways, poly (ADP-ribose) polymerase (PARP) inhibitors, agents targeting immune-suppressive regulators, and repurposed existing drugs. We particularly highlight clinical evidence and trace the ongoing clinical trials to investigate the translational value. Taken together, we conduct a thorough review on emerging agents for gynecological cancer treatment and further discuss their potential challenges and future opportunities.

Role of the RNA-binding protein family in gynecologic cancers

Gynecological cancers pose a threat to women's health. Although early-stage gynecological cancers show good outcomes after standardized treatment, the prognosis of patients with advanced, met-astatic, and recurrent cancers is poor. RNA-binding proteins (RBPs) are important cellular proteins that interact with RNA through RNA-binding domains and participate extensively in post-transcriptional regulatory processes, such as mRNA alternative splicing, polyadenylation, intracellular localization and stability, and translation. Abnormal RBP expression affects the normal function of oncogenes and tumor suppressor genes in many malignancies, thus leading to the occurrence or progression of cancers. Similarly, RBPs play crucial roles in gynecological carcinogenesis. We summarize the role of RBPs in gynecological malignancies and explore their potential in the diagnosis and treatment of cancers. The findings summarized in this review may provide a guide for future research on the functions of RBPs.

Regulatory mechanisms and therapeutic implications of insulin-like growth factor 2 mRNA-binding proteins, the emerging crucial m6A regulators of tumors

Insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs) serve essential biological functions as post-transcriptional performers, participating in the acquisition or maintenance of tumor hallmarks due to their distinct protein structures. Emerging evidence indicates that IGF2BPs belong to the class III type of RNA N6-methyladenosine (m6A) modification readers, controlling RNA stability, storage, localization, metabolism, and translation in multiple vital bioprocesses, particularly tumorigenesis and tumor progression. Here, we discuss the underlying regulatory mechanisms and pathological functions of IGF2BPs which act as m6A readers in the context of tumor pathogenesis and multidrug resistance. Furthermore, we highlight the potential of IGF2BPs as drug targets in clinical tumor treatment. Hence, precise and novel tumor therapeutic approaches could be uncovered by targeting epigenetic heterogeneity.

TMEM41A overexpression correlates with poor prognosis and immune alterations in patients with endometrial carcinoma

BACKGROUND

Expression levels of transmembrane protein 41A (TMEM41A) are related to the progression of malignant tumors. However, the association between TMEM41A expression and endometrial carcinoma (EC) remains unclear. This study aims to identify the roles of TMEM41A expression in the prognosis of patients with EC and its correlation with EC progression.

METHODS

The TMEM41A expression and its correlation with the survival of patients with EC were assessed. Cox regression analysis was used to identify the prognostic factors, while nomograms were used to examine the association between the prognostic factors and the survival of patients with EC. Finally, the link between TMEM41A level and immune microenvironment and RNA modifications was investigated in EC.

RESULTS

TMEM41A was overexpressed in EC. TMEM41A overexpression could diagnose the EC and evaluate the poor prognosis of patients. Overexpression of TMEM41A was associated with clinical stage, age, weight, histological subtype, tumor grade, and survival status of patients with EC. Clinical stage, age, tumor grade, radiotherapy, and TMEM41A overexpression were factors of poor prognosis in patients with EC. The nomograms revealed the correlation between the TMEM41A level and survival time of patients with EC at 1, 3, and 5 years. Furthermore, TMEM41A overexpression was significantly correlated with the level of the stromal score, immune score, estimate score, NK CD56 bright cells, iDC, NK cells, eosinophils, pDC, T cells, TReg, cytotoxic cells, mast cells, Th17 cells, neutrophils, aDC, NK CD56 dim cells, TFH, Th2 cells, CD8 T cells, macrophages, immune cell markers, and RNA modifications.

CONCLUSIONS

TMEM41A is overexpressed in EC tissues and is associated with the prognosis, immune microenvironment, and RNA modification. Our preliminary studies indicate that overexpression of TMEM41A can potentially serve as a biomarker for EC treatment.

ALKBH5-mediated m6A demethylation fuels cutaneous wound re-epithelialization by enhancing PELI2 mRNA stability

BACKGROUND

Impaired wound re-epithelialization contributes to cutaneous barrier reconstruction dysfunction. Recently, N⁶-methyladenosine (m⁶A) RNA modification has been shown to participate in the determination of RNA fate, and its aberration triggers the pathogenesis of numerous diseases. Howbeit, the function of m⁶A in wound re-epithelialization remains enigmatic.

METHODS

Alkbh5^‒/‒ mouse was constructed to study the rate of wound re-epithelialization after ALKBH5 ablation. Integrated high-throughput analysis combining methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA-seq was used to identify the downstream target of ALKBH5. In vitro and in vivo rescue experiments were conducted to verify the role of the downstream target on the functional phenotype of ALKBH5-deficient cells or animals. Furthermore, the interacting reader protein and regulatory mechanisms were determined through RIP-qPCR, RNA pull-down, and RNA stability assays.

RESULTS

ALKBH5 was specifically upregulated in the wound edge epidermis. Ablation of ALKBH5 suppressed keratinocyte migration and resulted in delayed wound re-epithelialization in Alkbh5^‒/‒ mouse. Integrated high-throughput analysis revealed that PELI2, an E3 ubiquitin protein ligase, serves as the downstream target of ALKBH5. Concordantly, exogenous PELI2 supplementation partially rescued keratinocyte migration and accelerated re-epithelialization in ALKBH5-deficient cells, both in vitro and in vivo. In terms of its mechanism, ALKBH5 promoted PELI2 expression by removing the m⁶A modification from PELI2 mRNA and enhancing its stability in a YTHDF2-dependent manner.

CONCLUSIONS

This study identifies ALKBH5 as an endogenous accelerator of wound re-epithelialization, thereby benefiting the development of a reprogrammed m⁶A targeted therapy for refractory wounds.

Crosstalk between m6A and coding/non-coding RNA in cancer and detection methods of m6A modification residues

N6-methyladenosine (m6A) is one of the most common and well-known internal RNA modifications that occur on mRNAs or ncRNAs. It affects various aspects of RNA metabolism, including splicing, stability, translocation, and translation. An abundance of evidence demonstrates that m6A plays a crucial role in various pathological and biological processes, especially in tumorigenesis and tumor progression. In this article, we introduce the potential functions of m6A regulators, including "writers" that install m6A marks, "erasers" that demethylate m6A, and "readers" that determine the fate of m6A-modified targets. We have conducted a review on the molecular functions of m6A, focusing on both coding and noncoding RNAs. Additionally, we have compiled an overview of the effects noncoding RNAs have on m6A regulators and explored the dual roles of m6A in the development and advancement of cancer. Our review also includes a detailed summary of the most advanced databases for m6A, state-of-the-art experimental and sequencing detection methods, and machine learning-based computational predictors for identifying m6A sites.

Constructing a novel signature and predicting the immune landscape of colon cancer using N6-methylandenosine-related lncRNAs

Background: Colon cancer (CC) is a prevalent malignant tumor that affects people all around the world. In this study, N6-methylandenosine-related long non-coding RNAs (m6A-related lncRNAs) in 473 colon cancers and 41 adjacent tissues of CC patients from The Cancer Genome Atlas (TCGA) were investigated. Method: The Pearson correlation analysis was conducted to examine the m6A-related lncRNAs, and the univariate Cox regression analysis was performed to screen 38 prognostic m6A-related lncRNAs. The least absolute shrinkage and selection operator (LASSO) regression analysis were carried out on 38 prognostic lncRNAs to develop a 14 m6A-related lncRNAs prognostic signature (m6A-LPS) in CC. The availability of the m6A-LPS was evaluated using the Kaplan-Meier and Receiver Operating Characteristic (ROC) curves. Results: Three m6A modification patterns with significantly different N stages, survival time, and immune landscapes were identified. It has been discovered that the m6A-LPS, which is based on 14 m6A-related lncRNAs (TNFRSF10A-AS1, AC245041.1, AL513550.1, UTAT33, SNHG26, AC092944.1, ITGB1-DT, AL138921.1, AC099850.3, NCBP2-AS1, AL137782.1, AC073896.3, AP006621.2, AC147651.1), may represent a new, promising biomarker with great potential. It was re-evaluated in terms of survival rate, clinical features, tumor infiltration immune cells, biomarkers related to Immune Checkpoint Inhibitors (ICIs), and chemotherapeutic drug efficacy. The m6A-LPS has been revealed to be a novel potential and promising predictor for evaluating the prognosis of CC patients. Conclusion: This study revealed that the risk signature is a promising predictive indicator that may provide more accurate clinical applications in CC therapeutics and enable effective therapy strategies for clinicians.

METTL3-Modulated circUHRF2 Promotes Colorectal Cancer Stemness and Metastasis through Increasing DDX27 mRNA Stability by Recruiting IGF2BP1

Increasing evidence has implicated that circular RNAs (circRNAs) exert important roles in colorectal cancer (CRC) occurrence and progression. However, the role of a novel circRNA, circUHRF2, remains unknown in CRC. Our work aimed at identifying the functional roles of circUHRF2 in CRC and illustrating the potential mechanisms. As assessed by quantitative real-time PCR (qRT-PCR), circUHRF2 and methyltransferase-like 3 (METTL3) were highly expressed in CRC specimens and cells. Sanger sequencing and RNase R assays were performed to verify the ring structure of circUHRF2. Notably, aberrantly increased expression of circUHRF2 was positively correlated with poor prognosis of CRC patients. Functional experiments indicated that CRC stemness, migration, and epithelial-mesenchymal transition (EMT) were suppressed by the knockdown of circUHRF2 or METTL3. Mechanistically, METTL3 enhanced circUHRF2 expression through N6-methyladenine (m⁶A) modification. Rescue experiments showed that overexpression of circUHRF2 reversed the repressive effect of METTL3 silencing on CRC progression. Moreover, circUHRF2 inhibited the loss of DEAD-box helicase 27 (DDX27) protein via promoting the interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and DDX27 mRNA. DDX27 knockdown repressed CRC malignant properties, which was counteracted by circUHRF2 overexpression. The in vivo assays in nude mice demonstrated that circUHRF2 or METTL3 silencing exerted a suppressive effect on CRC growth and liver metastasis via repressing DDX27 protein expression. Taken together, METTL3-mediated m⁶A modification upregulated circUHRF2 and subsequently inhibited loss of DDX27 protein via recruitment of IGF2BP1, which conferred CRC stemness and metastasis. These findings shed light on CRC pathogenesis and suggest circUHRF2 as a novel target for CRC treatment.