ALKBH5 decreases SLC7A11 expression by erasing m6A modification and promotes the ferroptosis of colorectal cancer cells

The regulatory mechanisms of N6-methyladenosine modification in ferroptosis and its implications in disease pathogenesis

HEADING AIMS

Based on the current knowledge of the molecular mechanisms by which m6A influences ferroptosis, our objective is to underscore the intricate and interdependent relationships between m6A and the principal regulatory pathways of ferroptosis, as well as other molecules, emphasizing its relevance to diseases associated with this cell death mode.

MATERIALS AND METHODS

We conducted a literature search using the keywords "m6A and ferroptosis" across PubMed, Web of Science, and Medline. The search was limited to English-language publications from 2017 to 2024. Retrieved articles were managed using Endnote software. Two authors independently screened the search results and reviewed the full texts of selected articles.

KEY FINDINGS

Abnormal m6A levels are often identified as critical regulators of ferroptosis. Specifically, "writers", "readers" and "erasers" that dynamically modulate m6A function regulate various pathways in ferroptosis including iron metabolism, lipid metabolism and antioxidant system. Additionally, we provide an overview of the role of m6A-mediated ferroptosis in multiple diseases and summarize the potential applications of m6A-mediated ferroptosis, including its use as a therapeutic target for diseases and as diagnostic as well as prognostic biomarkers.

SIGNIFICANCE

N6-methyladenosine (m6A) modification, a prevalent RNA modification in eukaryotic cells, is crucial in regulating various aspects of RNA metabolism. Notably, accumulating evidence has implicated m6A modification in ferroptosis, a form of iron-dependent cell death characterized by elevated iron levels and lipid peroxide accumulation. Overall, this review sheds light on the potential diagnostic and therapeutic applications of m6A regulators in addressing conditions associated with ferroptosis.

Fluoride exposure-induced gut microbiota alteration mediates colonic ferroptosis through N6-methyladenosine (m6A) mediated silencing of SLC7A11

Fluoride exposure is widespread worldwide and poses a significant threat to organisms, particularly to their gastrointestinal tracts. However, due to limited knowledge of the mechanism of fluoride induced intestinal injury, it has been challenging to develop an effective treatment. To address this issue, we used a series of molecular biology in vitro and in vivo experiments. NaF triggered m6A mediated ferroptosis to cause intestinal damage. Mechanistically, NaF exposure increased the m6A level of SLC7A11 mRNA, promoted YTHDF2 binding to m6A-modified SLC7A11 mRNA, drove the degradation of SLC7A11 mRNA, and led to a decrease in its protein expression, which eventually triggers ferroptosis. Moreover, NaF aggravated ferroptosis of the colon after antibiotics destroyed the composition of gut microbiota. 16 S rRNA sequencing and SPEC-OCCU plots, Zi-Pi relationships, and Spearman correlation coefficients verified that Lactobacillus murinus (ASV54, ASV58, and ASV82) plays a key role in the response to NaF-induced ferroptosis. Collectively, NaF-induced gut microbiota alteration mediates severe intestinal cell injury by inducing m6A modification-mediated ferroptosis. Our results highlight a key mechanism of the gut in response to NaF exposure and suggest a valuable theoretical basis for its prevention and treatment.

Multifaceted bioinformatic analysis of m6A-related ferroptosis and its link with gene signatures and tumour-infiltrating immune cells in gliomas

Whether N6-Methyladenosine (m6A)- and ferroptosis-related genes act on immune responses to regulate glioma progression remains unanswered. Data of glioma and corresponding normal brain tissues were fetched from the TCGA database and GTEx. Differentially expressed genes (DEGs) were identified for GO and KEGG enrichment analyses. The FerrDb database was based to yield ferroptosis-related DEGs. Hub genes were then screened out using the cytoHubba database and validated in clinical samples. Immune cells infiltrating into the glioma tissues were analysed using the CIBERSORT R script. The association of gene signature underlying the m6A-related ferroptosis with tumour-infiltrating immune cells and immune checkpoints in low-grade gliomas was analysed. Of 6298 DEGs enriched in mRNA modifications, 144 were ferroptosis-related; NFE2L2 and METTL16 showed the strongest positive correlation. METTL16 knockdown inhibited the migrative and invasive abilities of glioma cells and induced ferroptosis in vitro. NFE2L2 was enriched in the anti-m6A antibody. Moreover, METTL16 knockdown reduced the mRNA stability and level of NFE2L2 (both p < 0.05). Proportions of CD8+ T lymphocytes, activated mast cells and M2 macrophages differed between low-grade gliomas and normal tissues. METTL16 expression was negatively correlated with CD8+ T lymphocytes, while that of NFE2L2 was positively correlated with M2 macrophages and immune checkpoints in low-grade gliomas. Gene signatures involved in the m6A-related ferroptosis in gliomas were identified via bioinformatic analyses. NFE2L2 interacted with METTL16 to regulate the immune response in low-grade gliomas, and both molecules may be novel therapeutic targets for gliomas.

Role of N6-methyladenosine RNA modification in cancer

N6-methyladenosine (m6A) is the most abundant modification of RNA in eukaryotic cells. Previous studies have shown that m6A is pivotal in diverse diseases especially cancer. m6A corelates with the initiation, progression, resistance, invasion, and metastasis of cancer. However, despite these insights, a comprehensive understanding of its specific roles and mechanisms within the complex landscape of cancer is still elusive. This review begins by outlining the key regulatory proteins of m6A modification and their posttranslational modifications (PTMs), as well as the role in chromatin accessibility and transcriptional activity within cancer cells. Additionally, it highlights that m6A modifications impact cancer progression by modulating programmed cell death mechanisms and affecting the tumor microenvironment through various cancer-associated immune cells. Furthermore, the review discusses how microorganisms can induce enduring epigenetic changes and oncogenic effect in microorganism-associated cancers by altering m6A modifications. Last, it delves into the role of m6A modification in cancer immunotherapy, encompassing RNA therapy, immune checkpoint blockade, cytokine therapy, adoptive cell transfer therapy, and direct targeting of m6A regulators. Overall, this review clarifies the multifaceted role of m6A modification in cancer and explores targeted therapies aimed at manipulating m6A modification, aiming to advance cancer research and improve patient outcomes.

Complicated role of ALKBH5 in gastrointestinal cancer: an updated review

Gastrointestinal cancer is the most common malignancy in humans, often accompanied by poor prognosis. N6-methyladenosine (m6A) modification is widely present in eukaryotic cells as the most abundant RNA modification. It plays a crucial role in RNA splicing and processing, nuclear export, translation, and stability. Human AlkB homolog 5 (ALKBH5) is a type of RNA demethylase exhibiting abnormal expression in various gastrointestinal cancers.It is closely related to the tumorigenesis, proliferation, migration, and other biological functions of gastrointestinal cancer. However, recent studies indicated that the role and mechanism of ALKBH5 in gastrointestinal cancer are complicated and even controversial. Thus, this review summarizes recent advances in elucidating the role of ALKBH5 as a tumor suppressor or promoter in gastrointestinal cancer. It examines the biological functions of ALKBH5 and its potential as a therapeutic target, providing new perspectives and insights for gastrointestinal cancer research.

ALKBH5 targets ACSL4 mRNA stability to modulate ferroptosis in hyperbilirubinemia-induced brain damage

Bilirubin-induced brain damage is a serious clinical consequence of hyperbilirubinemia, yet the underlying molecular mechanisms remain largely unknown. Ferroptosis, an iron-dependent cell death, is characterized by iron overload and lipid peroxidation. Here, we report a novel regulatory mechanism of demethylase AlkB homolog 5 (ALKBH5) in acyl-coenzyme A synthetase long-chain family member 4 (ACSL4)-mediated ferroptosis in hyperbilirubinemia. Hyperdifferential PC12 cells and newborn Sprague-Dawley rats were used to establish in vitro and in vivo hyperbilirubinemia models, respectively. Proteomics, coupled with bioinformatics analysis, first suggested the important role of ferroptosis in hyperbilirubinemia-induced brain damage. In vitro experiments showed that ferroptosis is activated in hyperbilirubinemia, and ferroptosis inhibitors (desferrioxamine and ferrostatin-1) treatment effectively alleviates hyperbilirubinemia-induced oxidative damage. Notably, we observed that the ferroptosis in hyperbilirubinemia was regulated by m6A modification through the downregulation of ALKBH5 expression. MeRIP-seq and RIP-seq showed that ALKBH5 may trigger hyperbilirubinemia ferroptosis by stabilizing ACSL4 mRNA via m6A modification. Further, hyperbilirubinemia-induced oxidative damage was alleviated through ACSL4 genetic knockdown or rosiglitazone-mediated chemical repression but was exacerbated by ACSL4 overexpression. Mechanistically, ALKBH5 promotes ACSL4 mRNA stability and ferroptosis by combining the 669 and 2015 m6A modified sites within 3' UTR of ACSL4 mRNA. Our findings unveil a novel molecular mechanism of ferroptosis and suggest that m6A-dependent ferroptosis could be an underlying clinical target for the therapy of hyperbilirubinemia.

Changes of RNA m6A/m5C Modification Regulatory Molecules in Ferroptosis of T2DM Rat Pancreas

N6-methyladenine (m6A) and 5-methylcytosine (m5C) are two common forms of RNA methylation that play an important role in the epigenetics of type 2 diabetes mellitus (T2DM). One type of cell death, ferroptosis, has been implicated in islet β-cell damage in T2DM. Notably, RNA methylation, an upstream regulatory mechanism of mRNAs, can regulate the expression of ferroptosis signaling molecules, thereby affecting cell proliferation and death. Here, we found that the ferroptosis signaling pathway was activated in pancreas of T2DM rats, followed by significant changes in m6A/m5C modification regulatory molecules. These detection data together with the prediction results that m6A and m5C exist in the mRNAs of ferroptosis molecules, we speculate that m6A and m5C are probably involved in pancreatic cell damage by modifying of ferroptosis signaling molecules. In short, our findings provide a new research idea for future studies on the molecular mechanisms of pancreatic cell damage and point to a new direction for exploring the mechanisms of ferroptosis from the perspective of RNA methylation modification.

Ferroptosis: a critical mechanism of N6-methyladenosine modification involved in carcinogenesis and tumor progression

Ferroptosis is an iron-dependent regulatory cell necrosis induced by iron overload and lipid peroxidation. It occurs when multiple redox-active enzymes are ectopically expressed or show abnormal function. Hence, the precise regulation of ferroptosis-related molecules is mediated across multiple levels, including transcriptional, posttranscriptional, translational, and epigenetic levels. N6-methyladenosine (m6A) is a highly evolutionarily conserved epigenetic modification in mammals. The m6A modification is commonly linked to tumor proliferation, progression, and therapy resistance because it is involved in RNA metabolic processes. Intriguingly, accumulating evidence suggests that dysregulated ferroptosis caused by the m6A modification drives tumor development. In this review, we summarized the roles of m6A regulators in ferroptosis-mediated malignant tumor progression and outlined the m6A regulatory mechanism involved in ferroptosis pathways. We also analyzed the potential value and application strategies of targeting m6A/ferroptosis pathway in the clinical diagnosis and therapy of tumors.

Targeting ferroptosis regulators by natural products in colorectal cancer

Colorectal cancer (CRC) poses a significant global health challenge, ranking as the third most diagnosed cancer and the second leading cause of cancer-related deaths. Despite advancements in treatment, challenges such as delayed diagnosis, multidrug resistance, and limited therapeutic effectiveness persist, emphasizing the need for innovative approaches. This review explores the potential of natural products, nutraceuticals, and phytochemicals for targeting ferroptosis-related regulators as a novel strategy in CRC. Ferroptosis, a form of regulated cell death characterized by iron-dependent lethal lipid peroxide accumulation, holds substantial importance in CRC progression and therapy resistance. Natural products, known for their diverse bioactive effects and favorable safety profiles, emerge as promising candidates to induce ferroptosis in CRC cells. Exploring amino acid, iron, lipid metabolism regulators, and oxidative stress regulators reveals promising avenues for inducing cell death in CRC. This comprehensive review provides insights into the multifaceted effects of natural products on proteins integral to ferroptosis regulation, including GPX4, SLC7A11, ACSL4, NCOA4, and HO-1. By elucidating the intricate mechanisms through which natural products modulate these proteins, this review lays the foundation for a promising therapeutic strategy in CRC.

Demethylases in tumors and the tumor microenvironment: Key modifiers of N6-methyladenosine methylation

RNA methylation modifications are widespread in eukaryotes and prokaryotes, with N6-methyladenosine (m6A) the most common among them. Demethylases, including Fat mass and obesity associated gene (FTO) and AlkB homolog 5 (ALKBH5), are important in maintaining the balance between RNA methylation and demethylation. Recent studies have clearly shown that demethylases affect the biological functions of tumors by regulating their m6A levels. However, their effects are complicated, and even opposite results have appeared in different articles. Here, we summarize the complex regulatory networks of demethylases, including the most important and common pathways, to clarify the role of demethylases in tumors. In addition, we describe the relationships between demethylases and the tumor microenvironment, and introduce their regulatory mechanisms. Finally, we discuss evaluation of demethylases for tumor diagnosis and prognosis, as well as the clinical application of demethylase inhibitors, providing a strong basis for their large-scale clinical application in the future.

Insights into the Roles of Epigenetic Modifications in Ferroptosis

Ferroptosis is a non-apoptotic mode of cell death driven by membrane lipid peroxidation and is characterized by elevated intracellular levels of Fe2+, ROS, and lipid peroxidation. Studies have shown that ferroptosis is related to the development of multiple diseases, such as cancer, neurodegenerative diseases, and acute myeloid leukemia. Ferroptosis plays a dual role in the occurrence and development of these diseases. Ferroptosis mainly involves iron metabolism, ROS, and lipid metabolism. Various mechanisms, including epigenetic regulation, have been reported to be deeply involved in ferroptosis. Abnormal epigenetic modifications have been reported to promote tumor onset or other diseases and resistance to chemotherapy drugs. In recent years, diversified studies have shown that epigenetic modification is involved in ferroptosis. In this review, we reviewed the current resistance system of ferroptosis and the research progress of epigenetic modification, such as DNA methylation, RNA methylation, non-coding RNAs, and histone modification in cancer and other diseases by regulating ferroptosis.

Autophagy/ferroptosis in colorectal cancer: Carcinogenic view and nanoparticle-mediated cell death regulation

The cell death mechanisms have a long history of being evaluated in diseases and pathological events. The ability of triggering cell death is considered to be a promising strategy in cancer therapy, but some mechanisms have dual functions in cancer, requiring more elucidation of underlying factors. Colorectal cancer (CRC) is a disease and malignant condition of colon and rectal that causes high mortality and morbidity. The autophagy targeting in CRC is therapeutic importance and this cell death mechanism can interact with apoptosis in inhibiting or increasing apoptosis. Autophagy has interaction with ferroptosis as another cell death pathway in CRC and can accelerate ferroptosis in suppressing growth and invasion. The dysregulation of autophagy affects the drug resistance in CRC and pro-survival autophagy can induce drug resistance. Therefore, inhibition of protective autophagy enhances chemosensitivity in CRC cells. Moreover, autophagy displays interaction with metastasis and EMT as a potent regulator of invasion in CRC cells. The same is true for ferroptosis, but the difference is that function of ferroptosis is determined and it can reduce viability. The lack of ferroptosis can cause development of chemoresistance in CRC cells and this cell death mechanism is regulated by various pathways and mechanisms that autophagy is among them. Therefore, current review paper provides a state-of-art analysis of autophagy, ferroptosis and their crosstalk in CRC. The nanoparticle-mediated regulation of cell death mechanisms in CRC causes changes in progression. The stimulation of ferroptosis and control of autophagy (induction or inhibition) by nanoparticles can impair CRC progression. The engineering part of nanoparticle synthesis to control autophagy and ferroptosis in CRC still requires more attention.

Impact of curcumin on ferroptosis-related genes in colorectal cancer: Insights from in-silico and in-vitro studies

Colorectal cancer (CRC) is responsible for a significant number of cancer-related fatalities worldwide. Researchers are investigating the therapeutic potential of ferroptosis, a type of iron-dependent controlled cell death, in the context of CRC. Curcumin, a natural compound found in turmeric, exhibits anticancer properties. This study explores the effects of curcumin on genes related to ferroptosis (FRGs) in CRC. To gather CRC data, we used the Gene Expression Profiling Interactive Analysis (GEPIA) and Gene Expression Omnibus (GEO) databases, while FRGs were obtained from the FerrDb database and PubMed. We identified 739 CRC differentially expressed genes (DEGs) in CRC and discovered 39 genes that were common genes between FRGs and CRC DEGs. The DEGs related to ferroptosis were enriched with various biological processes and molecular functions, including the regulation of signal transduction and glucose metabolism. Using the Drug Gene Interaction Database (DGIdb), we predicted drugs targeting CRC-DEGs and identified 17 potential drug targets. Additionally, we identified eight essential proteins related to ferroptosis in CRC, including MYC, IL1B, and SLC1A5. Survival analysis revealed that alterations in gene expression of CDC25A, DDR2, FABP4, IL1B, SNCA, and TFAM were associated with prognosis in CRC patients. In SW480 human CRC cells, treatment with curcumin decreased the expression of MYC, IL1B, and EZH2 mRNA, while simultaneously increasing the expression of SLCA5 and CAV1. The findings of this study suggest that curcumin could regulate FRGs in CRC and have the potential to be utilized as a therapeutic agent for treating CRC.