N(6)-methyladenosine-mediated miR-380-3p maturation and upregulation promotes cancer aggressiveness in pancreatic cancer

Current insights on m6A RNA modification in acute leukemia: therapeutic targets and future prospects

RNA modification is the critical mechanism for regulating post-transcriptional processes. There are more than 150 RNA modifications reported so far, among which N6-Methyladenosine is the most prevalent one. M6A RNA modification complex consists of 'writers', 'readers' and 'erasers' which together in a group catalyze, recognize and regulate the methylation process of RNA and thereby regulate the stability and translation of mRNA. The discovery of erasers also known as demethylases, revolutionized the research on RNA modifications as it revealed that this modification is reversible. Since then, various studies have focused on discovering the role of m6A modification in various diseases especially cancers. Aberrant expression of these 'readers', 'writers', and 'erasers' is found to be altered in various cancers resulting in disturbance of cellular homeostasis. Acute leukemias are the most common cancer found in pediatric patients and account for 20% of adult cases. Dysregulation of the RNA modifying complex have been reported in development and progression of hematopoietic malignancies. Further, targeting m6A modification is the new approach for cancer immunotherapy and is being explored extensively. This review provides detailed information about current information on the role of m6A RNA modification in acute leukemia and their therapeutic potential.

Recent advances in noncoding RNA modifications of gastrointestinal cancer

Elucidating the mechanisms underlying cancer development and proliferation is important for the development of therapeutic methods for the complete cure of cancer. In particular, the identification of diagnostic markers for early detection and new therapeutic strategies for refractory gastrointestinal cancers are needed. Various abnormal phenomena occur in cancer cells, such as functional changes of proteins, led by genomic mutations, and changes in gene expression due to dysregulation of epigenetic regulation. This is no exception for noncoding RNA (ncRNA), which do not encode proteins. Recent reports have revealed that microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA) are deeply involved in cancer progression. These ncRNAs have attracted attention as gene expression regulatory molecules. Recent advances in technology have made it possible not only to read DNA and RNA sequences but also to study the modification state of each base. In particular, comprehensive analysis of N6-methyladenosine (m6A) has been performed by many research groups, with multiple studies reporting that m6A modifications of specific genes are associated with cancer progression. Based on the above, this review examines how ncRNA modifications are related to cancer progression in gastrointestinal cancers such as colorectal and pancreatic cancer. We also discuss enzyme inhibitors that have been reported to have drug discovery potential targeting m6A modifications. By utilizing the new perspective of ncRNA modification, we may be able to accumulate knowledge on the molecular biology of cancer and contribute to human health through diagnosis and treatment.

Effects of METTL3-METTL14 on primary microRNA processing by Drosha-DGCR8

MicroRNAs modulate most protein-coding genes, and many are regulated during maturation. Chemical modifications of primary transcripts containing microRNAs have been implicated in altering Microprocessor processing efficiency, a key initiating endonucleolytic step performed by Drosha and DGCR8. METTL3-METTL14 produces N 6 -methyladenosine which is the most common methylation for mRNAs. Genetic experiments suggested that METTL3-METTL14 promotes primary microRNA processing by Microprocessor, but the molecular mechanism still needs to be elucidated. We tested the hypothesis that METTL3-METTL14 or m 6 A may directly impact Drosha or DGCR8 function during primary microRNA processing. After reconstituting the methyltransferase and processing activities, we show that the presence of METTL3-METTL14 complexes does not affect the processing efficiency of Drosha-DGCR8. We also established a method to prepare m 6 A-modified primary microRNAs and used them to show that the processing of the transcripts with m 6 A is similar to those without any modification. Recombinant METTL3-METTL14 and DGCR8 do not form stable complexes, challenging the previous model that depends on enhanced DGCR8 recruitment. Therefore, METTL3-METTL14 or m 6 A modification does not generally promote Microprocessor-mediated microRNA processing, although they may impact certain cases.

Recent advances in the reciprocal regulation of m6A modification with non-coding RNAs and its therapeutic application in acute myeloid leukemia

N6-methyladenosine (m6A) is one of the most common modifications of RNA in eukaryotic cells and is involved in mRNA metabolism, including stability, translation, maturation, splicing, and export. m6A also participates in the modification of multiple types of non-coding RNAs, such as microRNAs, long non-coding RNAs, and circular RNAs, thereby affecting their metabolism and functions. Increasing evidence has revealed that m6A regulators, such as writers, erasers, and readers, perform m6A-dependent modification of ncRNAs, thus affecting cancer progression. Moreover, ncRNAs modulate m6A regulators to affect cancer development and progression. In this review, we summarize recent advances in understanding m6A modification and ncRNAs and provide insights into the interaction between m6A modification and ncRNAs in cancer. We also discuss the potential clinical applications of the mechanisms underlying the interplay between m6A modifications and ncRNAs in acute myeloid leukemia (AML). Therefore, clarifying the mutual regulation between m6A modifications and ncRNAs is of great significance to identify novel therapeutic targets for AML and has great clinical application prospects.

Fundamental insights and molecular interactions in pancreatic cancer: Pathways to therapeutic approaches

The gastrointestinal tract can be affected by a number of diseases that pancreatic cancer (PC) is a malignant manifestation of them. The prognosis of PC patients is unfavorable and because of their diagnosis at advanced stage, the treatment of this tumor is problematic. Owing to low survival rate, there is much interest towards understanding the molecular profile of PC in an attempt in developing more effective therapeutics. The conventional therapeutics for PC include surgery, chemotherapy and radiotherapy as well as emerging immunotherapy. However, PC is still incurable and more effort should be performed. The molecular landscape of PC is an underlying factor involved in increase in progression of tumor cells. In the presence review, the newest advances in understanding the molecular and biological events in PC are discussed. The dysregulation of molecular pathways including AMPK, MAPK, STAT3, Wnt/β-catenin and non-coding RNA transcripts has been suggested as a factor in development of tumorigenesis in PC. Moreover, cell death mechanisms such as apoptosis, autophagy, ferroptosis and necroptosis demonstrate abnormal levels. The EMT and glycolysis in PC cells enhance to ensure their metastasis and proliferation. Furthermore, such abnormal changes have been used to develop corresponding pharmacological and nanotechnological therapeutics for PC.

Methyltransferase-like 3 modifications of RNAs: Implications for the pathology in the endocrine system

Methyltransferase-like 3 (METTL3) is the most well-known element of N6-methyladenosine modification on RNAs. METTL3 deposits a methyl group onto target RNAs to modify their expression, ultimately regulating various physiological and pathological events. Numerous studies have suggested the significant role of METTL3 in endocrine dysfunction and related disorders. However, reviews that summarize and interpret these studies are lacking. In this review, we systematically analyze such studies, including obesity, type 2 diabetes mellitus (T2DM), T2DM-induced diseases, pancreatic cancer, and thyroid carcinoma. This review indicates that METTL3 contributes remarkably to the endocrine dysfunction and progression of obesity, T2DM, T2DM-induced diseases, pancreatic cancer, and thyroid carcinoma. In conclusion, this review provides a comprehensive interpretation of the mechanism via which METTL3 functions on RNAs and regulates various endocrine dysfunction events and suggest potential associated correlations. Our review, thus, provides a valuable reference for further fundamental studies and clinical applications.

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

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

New understandings of the genetic regulatory relationship between non-coding RNAs and m6A modification

One of the most frequent epigenetic modifications of RNA in eukaryotes is N6 methyladenosine (m6A), which is mostly present in messenger RNAs. Through the influence of several RNA processing stages, m6A modification is a crucial approach for controlling gene expression, especially in cancer progression. It is universally acknowledged that numerous non-coding RNAs (ncRNAs), such as microRNAs, circular RNAs, long non-coding RNAs, and piRNAs, are also significantly affected by m6A modification, and the complex genetic regulatory relationship between m6A and ncRNAs plays a pivotal role in the development of cancer. The connection between m6A modifications and ncRNAs offers an opportunity to explore the oncogene potential regulatory mechanisms and suggests that m6A modifications and ncRNAs could be vital biomarkers for multiple cancers. In this review, we discuss the mechanisms of interaction between m6A methylation and ncRNAs in cancer, and we also summarize diagnostic and prognostic biomarkers for clinical cancer detection. Furthermore, our article includes some methodologies for identifying m6A sites when assessing biomarker potential.

Role of m6A modification in regulating the PI3K/AKT signaling pathway in cancer

The phosphoinositide 3-kinase (PI3K)/AKT signaling pathway plays a crucial role in the pathogenesis of cancer. The dysregulation of this pathway has been linked to the development and initiation of various types of cancer. Recently, epigenetic modifications, particularly N6-methyladenosine (m6A), have been recognized as essential contributors to mRNA-related biological processes and translation. The abnormal expression of m6A modification enzymes has been associated with oncogenesis, tumor progression, and drug resistance. Here, we review the role of m6A modification in regulating the PI3K/AKT pathway in cancer and its implications in the development of novel strategies for cancer treatment.

Regulatory role of RNA modifications in the treatment of pancreatic ductal adenocarcinoma (PDAC)

Pancreatic ductal adenocarcinoma (PDAC) is an extremely life-threatening malignancy with a relatively unfavorable prognosis. The early occurrence of metastasis and local recurrence subsequent to surgery contribute to the poor survival rates of PDAC patients, thereby limiting the effectiveness of surgical intervention. Additionally, the desmoplastic and immune-suppressive tumor microenvironment of PDAC diminishes its responsiveness to conventional treatment modalities such as chemotherapy, radiotherapy, and immunotherapy. Therefore, it is imperative to identify novel therapeutic targets for PDAC treatment. Chemical modifications are prevalent in various types of RNA and exert significant influence on their structure and functions. RNA modifications, exemplified by m6A, m5C, m1A, and Ψ, have been identified as general regulators of cellular functions. The abundance of specific modifications, such as m6A, has been correlated with cell proliferation, invasion, migration, and patient prognosis in PDAC. Pre-clinical data has indicated that manipulating RNA modification regulators could enhance the efficacy of chemotherapy, radiotherapy, and immunotherapy. Therefore, targeting RNA modifications in conjunction with current adjuvant or neoadjuvant therapy holds promise. The objective of this review is to provide a comprehensive overview of RNA modifications in PDAC treatment, encompassing their behaviors, mechanisms, and potential treatment targets. Therefore, it aims to stimulate the development of novel therapeutic approaches and future clinical trials.

miR-380-3p promotes β-casein expression by targeting αS1-casein in goat mammary epithelial cells

OBJECTIVE

αS1-Casein is more closely associated with milk allergic reaction than other milk protein components. microRNA (miRNA) is a class of small non-coding RNAs that modulate multiple biological progresses by the target gene. However, the post-transcriptional regulation of αS1-casein expression by miRNA in ruminants remains unclear. This study aims to explore the regulatory roles of miR-380-3p on αS1-casein synthesis in goat mammary epithelial cells (GMEC).

METHODS

αS1-Casein gene and miR-380-3p expression was measured in dairy goat mammary gland by quantitative real-time polymerase chain reaction (qRT-PCR). miR-380-3p overexpression and knockdown were performed by miR-380-3p mimic or inhibitor in GMEC. The effect of miR-380-3p on αS1-casein synthesis was detected by qRT-PCR, western blot, luciferase and chromatin immunoprecipitation assays in GMEC.

RESULTS

Compared with middle-lactation period, αS1-casein gene expression is increased, while miR-380-3p expression is decreased during peak-lactation of dairy goats. miR-380-3p reduces αS1-casein abundance by targeting the 3'-untranslated region (3'UTR) of αS1-casein mRNA in GMEC. miR-380-3p enhances β-casein expression and signal transducer and activator of transcription 5a (STAT5a) activity. Moreover, miR-380-3p promotes β-casein abundance through target gene αS1-casein, and activates β-casein transcription by enhancing the binding of STAT5 to β-casein gene promoter region.

CONCLUSION

miR-380-3p decreases αS1-casein expression and increases β-casein expression by targeting αS1-casein in GMEC, which supplies a novel strategy for reducing milk allergic potential and building up milk quality in ruminants.

METTL14‑mediated RNA methylation in digestive system tumors

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

Role of RNA methylation in the regulation of pancreatic cancer stem cells (Review)

Pancreatic cancer stem cells (CSCs) play a key role in the initiation and progression of pancreatic adenocarcinoma (PDAC). CSCs are responsible for resistance to chemotherapy and radiation, and for cancer metastasis. Recent studies have indicated that RNA methylation, a type of RNA modification, predominantly occurring as m6A methylation, plays an important role in controlling the stemness of cancer cells, therapeutic resistance against chemotherapy and radiation therapy, and their overall relevance to a patient's prognosis. CSCs regulate various behaviors of cancer through cell-cell communication by secreting factors, through their receptors, and through signal transduction. Recent studies have shown that RNA methylation is involved in the biology of the heterogeneity of PDAC. The present review provides an update on the current understanding of RNA modification-based therapeutic targets against deleterious PDAC. Several key pathways and agents that can specifically target CSCs have been identified, thus providing novel insights into the early diagnosis and efficient treatment of PDAC.

The significance of N6-methyladenosine-modified non-coding RNAs in different disorders

N6-methyladenosine (m6A) is the most widespread endogenous modification affecting the expression of eukaryotic mRNA transcripts. Recent studies have shown that the m6A marks within non-coding RNAs can affect their functions and expression in a manner similar to that of mRNA-coding genes. Since non-coding RNAs are involved in the pathophysiology of several disorders, identification of the role of m6A marks in the regulation of expression of non-coding RNAs can open a new era for identifying underlying mechanisms of several disorders and designing novel therapeutic modalities for a variety of disorders, particularly cancers. Moreover, a number of non-coding RNAs can affect m6A levels. In the current review, we discuss the impacts of m6A marks on the expression of non-coding RNAs in the context of different disorders, such as bone, gastrointestinal, neurologic, renal, pulmonary, hepatic and other disorders.