ALKBH5 inhibits thyroid cancer progression by promoting ferroptosis through TIAM1-Nrf2/HO-1 axis

FTO alleviated ferroptosis in septic cardiomyopathy via mediating the m6A modification of BACH1

Sepsis is a global health challenge that results in systemic inflammation, oxidative stress, and multi-organ dysfunction, with the heart being particularly susceptible. This study aimed to elucidate the effect of FTO, a key regulator in m6A methylation in septic cardiomyopathy, and its potential therapeutic implications. Cellular and animal models of septic myocardial injury were established. Moreover, it was revealed that ferroptosis, which is a form of programmed necrosis occurring with iron dependence, was activated within cardiomyocytes during septic conditions. The overexpression of FTO-suppressed ferroptosis alleviated heart inflammation and dysfunction and improved survival rates in vivo. However, the protective effects of FTO were attenuated by the overexpression of BACH1, which is a molecule negatively correlated with FTO. Mechanistically, FTO modulated the m6A modification of BACH1, suggesting a complex interplay in the regulation of cardiomyocyte damage and sepsis. Our findings reveal the potential of targeting the FTO/BACH1 axis and ferroptosis inhibitors as therapeutic strategies for sepsis-induced cardiac injuries.

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.

The potential roles of HIF-1α in epithelial-mesenchymal transition and ferroptosis in tumor cells

In tumors, the rapid proliferation of cells and the imperfect blood supply system lead to hypoxia, which can regulate the adaptation of tumor cells to the hypoxic environment through hypoxia-inducible factor-1α (HIF-1α) and promote tumor development in multiple ways. Recent studies have found that epithelial-mesenchymal transition (EMT) and ferroptosis play important roles in the progression of tumor cells. The activation of HIF-1α is considered a key factor in inducing EMT in tumor cells. When HIF-1α is activated, it can regulate EMT-related genes, causing tumor cells to gradually lose their epithelial characteristics and acquire more invasive mesenchymal traits. The occurrence of EMT allows tumor cells to better adapt to changes in the surrounding tissue, enhancing their migratory and invasive capabilities, thus promoting tumor progression. At the same time, HIF-1α also plays a crucial regulatory role in ferroptosis in tumor cells. In a hypoxic environment, HIF-1α may affect processes such as iron metabolism and oxidative stress responses, inducing ferroptosis in tumor cells. This article briefly reviews the dual role of HIF-1α in EMT and ferroptosis in tumor cells, helping to gain a deeper understanding of the regulatory pathways of HIF-1α in the development of tumor cells, providing a new perspective for understanding the pathogenesis of tumors. The regulation of HIF-1α may become an important strategy for future tumor therapy.

Ferroptosis in thyroid cancer: Potential mechanisms, effective therapeutic targets and predictive biomarker

Thyroid cancer is a prevalent endocrine malignancy whose global incidence has risen over the past several decades. Ferroptosis, a regulated form of cell death distinguished by the excessive buildup of iron-dependent lipid peroxidates, stands out from other programmed cell death pathways in terms of morphological and molecular characteristics. Increasing evidence suggests a close association between thyroid cancer and ferroptosis, that is, inducing ferroptosis effectively suppresses the proliferation of thyroid cancer cells and impede tumor advancement. Therefore, ferroptosis represents a promising therapeutic target for the clinical management of thyroid cancer in clinical settings. Alterations in ferroptosis-related genes hold potential for prognostic prediction in thyroid cancer. This review summarizes current studies on the role of ferroptosis in thyroid cancer, elucidating its mechanisms, therapeutic targets, and predictive biomarkers. The findings underscore the significance of ferroptosis in thyroid cancer and offer valuable insights into the development of innovative treatment strategies and accurate predictors for the thyroid cancer.

High expression of AlkB homolog 5 suppresses the progression of non-small cell lung cancer by facilitating ferroptosis through m6A demethylation of SLC7A11

OBJECTIVE

Non-small cell lung cancer (NSCLC) is a prevailing LC characterized by poor outcomes. AlkB homolog 5 (ALKBH5) functions as a tumor suppressor in several cancers. This study delved into the role of ALKBH5 in NSCLC development.

METHODS

TCGA database predicted ALKBH5 expression in NSCLC patients. ALKBH5 levels in NSCLC and human bronchial epithelial cells were determined. pcDNA3.1-ALKBH5/NC, pcDNA3.1-SLC7A11/NC, and ferrostatin-1 were used to explore the interactions among ALKBH5, SLC7A11, and ferroptosis. SLC7A11 mRNA and its protein levels were measured by RT-qPCR and Western blot. Cell viability, apoptosis, migration, and invasion were assessed by CCK-8, flow cytometry, and Transwell. Total N6-methyladenosine (m6A) quantification and its enrichment on SLC7A11 mRNA were determined, followed by the observation of Ki67, ALKBH5 and SLC7A11-positive cell numbers. Glutathione (GSH), lipid reactive oxygen species (lipid-ROS), malondialdehyde (MDA), and iron ion contents were determined. Animal experiments further analyzed the role of ALKBH5 in tumor development and glutathione peroxidase 4 (GPX4) expression.

RESULTS

Bioinformatics analysis revealed the lowly-expressed ALKBH5 in LC patients. ALKBH5 was downregulated in NSCLC cells and its upregulation repressed proliferation activity, invasion, and migration, and facilitated apoptosis. ALKBH5 upregulation decreased GSH, increased lipid-ROS, MDA, and iron ion contents, and downregulated SLC7A11 by reducing m6A modification. SLC7A11 upregulation partly annulled the effect of ALKBH5 overexpression on cell ferroptosis and malignant behaviors. In vivo assays elucidated the suppression of ALKBH5 upregulation on tumor development and GPX4 levels.

CONCLUSION

ALKBH5 upregulation downregulates SLC7A11 transcription by decreasing m6A modification, thus promoting NSCLC cell ferroptosis and ultimately repressing NSCLC progression.

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.

Exosome-transported circ_0061407 and circ_0008103 play a tumour-repressive role and show diagnostic value in non-small-cell lung cancer

BACKGROUND

Circular RNAs (circRNAs), one of the major contents of exosomes, have been shown to participate in the occurrence and progression of cancers. The role and the diagnostic potential of exosome-transported circRNAs in non-small-cell lung cancer (NSCLC) remain largely unknown.

METHODS

The NSCLC-associated exosomal circ_0061407 and circ_0008103 were screened by circRNA microarray. The role of circ_0061407 and circ_0008103 in NSCLC was examined in vitro and in vivo. The encapsulation of the two circRNAs into exosomes and the transport to recipient cells were observed by confocal microscopy. The effects of exosome-transported circ_0061407 and circ_0008103 on recipient cells were investigated using a co-culture device. Bioinformatics analyses were performed to predict the mechanisms by which circ_0061407 and circ_0008103 affected NSCLC. The quantitative polymerase chain reaction was used to quantify the exosome-containing circ_0061407 and circ_0008103 in the serum samples of healthy, pneumonia, benign lung tumours, and NSCLC. The diagnostic efficacy was evaluated using receiver operating characteristic curves.

RESULTS

The levels of circ_0061407 and circ_0008103 within exosomes were down-regulated in the serum of patients with NSCLC. The up-regulation of circ_0061407 and circ_0008103 inhibited the proliferation, migration/invasion, cloning formation of NSCLC cells in vitro and inhibited lung tumour growth in vivo. Circ_0061407 and circ_0008103 were observed to be packaged in exosomes and transported to recipient cells, where they inhibited the proliferation, migration/invasion, and cloning formation abilities of the recipient cells. Moreover, circ_0061407 and circ_0008103 might be involved in the progression of NSCLC by interacting with microRNAs and proteins. Additionally, lower serum exosomal circ_0061407 and circ_0008103 levels were associated with advanced pathological staging and distant metastasis.

CONCLUSIONS

This study identified two novel exosome-transported circRNAs (circ_0061407 and circ_0008103) associated with NSCLC. These findings may provide additional insights into the development of NSCLC and potential diagnostic biomarkers for NSCLC.

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.

FTO ameliorates doxorubicin-induced cardiotoxicity by inhibiting ferroptosis via P53-P21/Nrf2 activation in a HuR-dependent m6A manner

Doxorubicin (DOX)-induced cardiotoxicity seriously limits its clinical applicability, and no therapeutic interventions are available. Ferroptosis, an iron-dependent regulated cell death characterised by lipid peroxidation, plays a pivotal role in DOX-induced cardiotoxicity. N6-methyladenosine (m6A) methylation is the most frequent type of RNA modification and involved in DOX-induced ferroptosis, however, its underlying mechanism remains unclear. P21 was recently found to inhibit ferroptosis by interacting with Nrf2 and is regulated in a P53-dependent or independent manner, such as through m6A modification. In the present study, we investigated the mechanism underlying m6A modification in DOX-induced ferroptosis by focusing on P21. Our results show that fat mass and obesity-associated protein (FTO) down-regulation was associated with DOX-induced cardiotoxicity. FTO over-expression significantly improved cardiac function and cell viability in DOX-treated mouse hearts and H9C2 cells. FTO over-expression significantly inhibited DOX-induced ferroptosis, and the Fer-1 inhibition of ferroptosis significantly reduced DOX-induced cardiotoxicity. P21 was significantly upregulated by FTO and activated Nrf2, playing a crucial role in the anti-ferroptotic effect. FTO upregulated P21/Nrf2 in a P53-dependent manner by mediating the demethylation of P53 or in a P53-independent manner by mediating P21/Nrf2 directly. Human antigen R (HuR) is crucial for FTO-mediated regulation of ferroptosis and P53-P21/Nrf2. Notably, we also found that P21 inhibition in turn inhibited HuR and P53 expression, while HuR inhibition further inhibited FTO expression. RNA immunoprecipitation assay showed that HuR binds to the transcripts of FTO and itself. Collectively, FTO inhibited DOX-induced ferroptosis via P21/Nrf2 activation by mediating the m6A demethylation of P53 or P21/Nrf2 in a HuR-dependent manner and constituted a positive feedback loop with HuR and P53-P21. Our findings provide novel insight into key functional mechanisms associated with DOX-induced cardiotoxicity and elucidate a possible therapeutic approach.

N6-methyladenosine promotes aberrant redox homeostasis required for arsenic carcinogenesis by controlling the adaptation of key antioxidant enzymes

N6-methyladenosine (m6A), a high-profile RNA epigenetic modification, responds to oxidative stress and temporal-specifically mediates arsenic carcinogenesis. However, how m6A affects aberrant redox homeostasis required for arsenic carcinogenesis is poorly understood. Here, we established arsenic-carcinogenic models of different stages, including As-treated, As-transformed, and As-tumorigenic cell models. We found that arsenic-induced reactive oxygen species (ROS) elevated m6A levels, thus triggering m6A-dependent antioxidant defenses. During arsenic-induced cell transformation, METTL3-upregulated m6A on the mRNAs of SOD1, SOD2, CAT, TXN, and GPX1 promoted the mRNA translation and protein expressions of these antioxidant enzymes by increasing YTHDF1-mediated mRNA stability. Meanwhile, FTO-downregulated m6A on PRDX5 mRNA increased PRDX5 translation and expression by reducing YTHDF2-mediated mRNA decay. After upregulated antioxidant defenses balanced with high levels of ROS induced by arsenic, the m6A balance formed in mRNAs of six key antioxidant enzymes (SOD1, SOD2, CAT, TXN, GPX1, and PRDX5) and promoted high expressions of these antioxidant enzymes to maintain aberrant redox homeostasis. METTL3 inhibitor STM2457, FTO inhibitor FB23-2, or YTHDF1 knockdown disturbed the aberrant redox homeostasis by breaking the m6A balance, causing cell death in arsenic-induced tumors. Our results demonstrated that m6A promotes the formation and maintenance of aberrant redox homeostasis required for arsenic carcinogenesis by time-dependently orchestrating the adaptive expressions of six key m6A-targeted antioxidant enzymes. This study advances our understanding of arsenic carcinogenicity from the novel aspect of m6A-dependent adaptation to arsenic-induced oxidative stress.

AKR1C3 silencing inhibits autophagy-dependent glycolysis in thyroid cancer cells by inactivating ERK signaling

Thyroid cancer is a highly differentiated and poorly malignant tumor. Interfering with glycolysis has become an effective means of controlling cancer progression and autophagy is negatively correlated with glycolysis. Aldo-keto reductase family 1 member C3 (AKR1C3) has been demonstrated to be highly expressed in thyroid cancer tissue and the higher AKR1C3 expression predicted the worse prognosis. We aimed to explore whether AKR1C3 could affect thyroid cancer progression by regulating autophagy-dependent glycolysis. AKR1C3 expression in thyroid cancer cells was detected by western blot. Then, AKR1C3 was knocked down by transfection with short hairpin RNA specific to AKR1C3 in the absence or presence of 3-methyladenine (3-MA) or PMA treatment. Cell cycle and apoptosis was detected by flow cytometry. Immunofluorescence staining was used to analyze LC3B expression. Extracellular acidification, glucose uptake and lactic acid secretion were detected. To evaluate the tumorigenicity of AKR1C3 insufficiency on thyroid cancer in vivo, TPC-1 cells with AKR1C3 knockdown were injected subcutaneously into nude mice. Then, cyclinD1 and Ki67 expression in tumorous tissues was measured by immunohistochemical analysis. Apoptosis was assessed by terminal-deoxynucleoitidyl transferase mediated nick end labeling staining. Additionally, the expression of proteins related to cell cycle, apoptosis, glycolysis, autophagy, and extracellular signal-regulated kinase (ERK) signaling in cells and tumor tissues was assessed by western blot. Highly expressed AKR1C3 was observed in thyroid cancer cells. AKR1C3 knockdown induced cell cycle arrest and apoptosis of TPC-1 cells. Besides, autophagy was activated and glycolysis was inhibited following AKR1C3 silencing, and 3-MA treatment restored the impacts of AKR1C3 silencing on glycolysis. The further experiments revealed that AKR1C3 insufficiency inhibited ERK signaling and PMA application reversed AKR1C3 silencing-induced autophagy in TPC-1 cells. The in vivo results suggested that AKR1C3 knockdown inhibited the development of subcutaneous TPC-1 tumors in nude mice and inactivated the ERK signaling. Collectively, AKR1C3 silencing inhibited autophagy-dependent glycolysis in thyroid cancer by inactivating ERK signaling.

Targeting epigenetic and posttranslational modifications regulating ferroptosis for the treatment of diseases

Ferroptosis, a unique modality of cell death with mechanistic and morphological differences from other cell death modes, plays a pivotal role in regulating tumorigenesis and offers a new opportunity for modulating anticancer drug resistance. Aberrant epigenetic modifications and posttranslational modifications (PTMs) promote anticancer drug resistance, cancer progression, and metastasis. Accumulating studies indicate that epigenetic modifications can transcriptionally and translationally determine cancer cell vulnerability to ferroptosis and that ferroptosis functions as a driver in nervous system diseases (NSDs), cardiovascular diseases (CVDs), liver diseases, lung diseases, and kidney diseases. In this review, we first summarize the core molecular mechanisms of ferroptosis. Then, the roles of epigenetic processes, including histone PTMs, DNA methylation, and noncoding RNA regulation and PTMs, such as phosphorylation, ubiquitination, SUMOylation, acetylation, methylation, and ADP-ribosylation, are concisely discussed. The roles of epigenetic modifications and PTMs in ferroptosis regulation in the genesis of diseases, including cancers, NSD, CVDs, liver diseases, lung diseases, and kidney diseases, as well as the application of epigenetic and PTM modulators in the therapy of these diseases, are then discussed in detail. Elucidating the mechanisms of ferroptosis regulation mediated by epigenetic modifications and PTMs in cancer and other diseases will facilitate the development of promising combination therapeutic regimens containing epigenetic or PTM-targeting agents and ferroptosis inducers that can be used to overcome chemotherapeutic resistance in cancer and could be used to prevent other diseases. In addition, these mechanisms highlight potential therapeutic approaches to overcome chemoresistance in cancer or halt the genesis of other diseases.

miR-590-5p/Tiam1-mediated glucose metabolism promotes malignant evolution of pancreatic cancer by regulating SLC2A3 stability

BACKGROUND

T lymphoma invasion and metastasis 1 (Tiam1) is a tumor related gene that specifically activates Rho-like GTPases Rac1 and plays a critical role in the progression of various malignancies. Glycolysis plays an important role in cancer progression, it is crucial for supplying energy and producing metabolic end products, which can maintain the survival of tumor cells. As yet, however, the mechanism of Tiam1 in glycolysis reprogramming of pancreatic cancer (PC) remains to be clarified. Here, we investigated the functional role of Tiam1 in PC cell proliferation, metastasis and glycolysis reprogramming. It is expected to provide a new direction for clinical treatment.

METHODS

The clinical relevance of Tiam1 was evaluated in 66 patients with PC, the effect of Tiam1 on cell proliferation was detected via 5-Ethynyl-2'-deoxyuridine (EdU) and colony formation. The ability of cell migration was detected by the wound healing and Transwell. Quantitative real time polymerase chain reaction (qRT-PCR) and luciferase reporter gene experiments clarify the regulatory relationship of miR-590-5p inhibiting Tiam1. Detection of the molecular mechanism of Tiam1 regulating glucose metabolism reprogramming in PC by glucose metabolism kit. RNA sequencing and Co-Immunoprecipitation (CoIP) have identified glucose transporter protein 3 (SLC2A3) as a key downstream target gene for miR-590-5p/Tiam1.

RESULTS

We found that Tiam1 expression increased in PC tissues and was associated with lymph node metastasis. The silencing or exogenous overexpression of Tiam1 significantly altered the proliferation, invasion, and angiogenesis of PC cells through glucose metabolism pathway. In addition, Tiam1 could interact with the crucial SLC2A3 and promote the evolution of PC in a SLC2A3-dependent manner. Moreover, miR-590-5p was found to exacerbate the PC cell proliferation, migration and invasion by targeting Tiam1. Furthermore, the reversing effects on proliferation, migration and invasion were found in PC cells with miR-590-5p/Tiam1 overexpression after applying glucose metabolism inhibition.

CONCLUSIONS

Our findings demonstrate the critical role of Tiam1 in PC development and the miR-590-5p/Tiam1/SLC2A3 signaling pathway may serve as a target for new PC therapeutic strategies.

FTO Sensitizes Oral Squamous Cell Carcinoma to Ferroptosis via Suppressing ACSL3 and GPX4

Ferroptosis is a newly established form of regulated cell death characterized by intracellular lipid peroxidation and iron accumulation that may be a promising cancer treatment strategy. However, the function and therapeutic value of ferroptosis in oral squamous cell carcinoma (OSCC) remain inadequately understood. In the present study, we investigated the biological role of the fat mass and obesity-associated gene (FTO) in ferroptosis in the context of OSCC. We found that OSCC had greater potential for ferroptosis, and FTO is associated with ferroptosis. Furthermore, higher FTO expression sensitized OSCC cells to ferroptosis in vitro and in vivo. Mechanistically, FTO suppressed the expression of anti-ferroptotic factors, acyl-CoA synthetase long-chain family member 3 (ACSL3) and glutathione peroxidase 4 (GPX4), by demethylating the m6A modification on the mRNA of ACSL3 and GPX4 and decreasing their stability. Taken together, our findings revealed that FTO promotes ferroptosis through ACSL3 and GPX4 regulation. Thus, ferroptosis activation in OSCC with high FTO levels may serve as a potential therapeutic target.

Effects of S-Adenosylhomocysteine Hydrolase Downregulation on Wnt Signaling Pathway in SW480 Cells

S-adenosylhomocysteine hydrolase (AHCY) deficiency results mainly in hypermethioninemia, developmental delay, and is potentially fatal. In order to shed new light on molecular aspects of AHCY deficiency, in particular any changes at transcriptome level, we enabled knockdown of AHCY expression in the colon cancer cell line SW480 to simulate the environment occurring in AHCY deficient individuals. The SW480 cell line is well known for elevated AHCY expression, and thereby represents a suitable model system, in particular as AHCY expression is regulated by MYC, which, on the other hand, is involved in Wnt signaling and the regulation of Wnt-related genes, such as the β-catenin co-transcription factor LEF1 (lymphoid enhancer-binding factor 1). We selected LEF1 as a potential target to investigate its association with S-adenosylhomocysteine hydrolase deficiency. This decision was prompted by our analysis of RNA-Seq data, which revealed significant changes in the expression of genes related to the Wnt signaling pathway and genes involved in processes responsible for epithelial-mesenchymal transition (EMT) and cell proliferation. Notably, LEF1 emerged as a common factor in these processes, showing increased expression both on mRNA and protein levels. Additionally, we show alterations in interconnected signaling pathways linked to LEF1, causing gene expression changes with broad effects on cell cycle regulation, tumor microenvironment, and implications to cell invasion and metastasis. In summary, we provide a new link between AHCY deficiency and LEF1 serving as a mediator of changes to the Wnt signaling pathway, thereby indicating potential connections of AHCY expression and cancer cell phenotype, as Wnt signaling is frequently associated with cancer development, including colorectal cancer (CRC).

The emerging roles of N6-methyladenosine RNA modifications in thyroid cancer

Thyroid cancer (TC) is the most predominant malignancy of the endocrine system, with steadily growing occurrence and morbidity worldwide. Although diagnostic and therapeutic methods have been rapidly developed in recent years, the underlying molecular mechanisms in the pathogenesis of TC remain enigmatic. The N6-methyladenosine(m6A) RNA modification is designed to impact RNA metabolism and further gene regulation. This process is intricately regulated by a variety of regulators, such as methylases and demethylases. Aberrant m6A regulators expression is related to the occurrence and development of TC and play an important role in drug resistance. This review comprehensively analyzes the effect of m6A methylation on TC progression and the potential clinical value of m6A regulators as prognostic markers and therapeutic targets in this disease.

Regulation of m6A modification on ferroptosis and its potential significance in radiosensitization

Radiotherapy is often used to treat various types of cancers, but radioresistance greatly limits the clinical efficiency. Recent studies have shown that radiotherapy can lead to ferroptotic cancer cell deaths. Ferroptosis is a new type of programmed cell death caused by excessive lipid peroxidation. The induction of ferroptosis provides a potential therapeutic strategy for radioresistance. As the most common post-transcriptional modification of mRNA, m6A methylation is widely involved in the regulation of various physiopathological processes by regulating RNA function. Dynamic m6A modification controlled by m6A regulatory factors also affects the susceptibility of cells to ferroptosis, thereby determining the radiosensitivity of tumor cells to radiotherapy. In this review, we summarize the mechanism and significance of radiotherapy induced ferroptosis, analyze the regulatory characteristics of m6A modification on ferroptosis, and discuss the possibility of radiosensitization by enhancing m6A-mediated ferroptosis. Clarifying the regulation of m6A modification on ferroptosis and its significance in the response of tumor cells to radiotherapy will help us identify novel targets to improve the efficacy of radiotherapy and reduce or overcome radioresistance.

Insights into the role of N6-methyladenosine in ferroptosis

N6-methyladenosine (m6A) methylation modification is one of the most prevalent epigenetic modifications of eukaryotic RNA. m6A methylation is widely associated with many biological processes through the modification of RNA metabolism and is associated with multiple disease states. As a newly discovered regulatory cell death in recent years, ferroptosis is an iron-dependent cell death characterized by excessive lipid peroxidation. Emerging evidence supports that ferroptosis has a significant role in the progression of diverse diseases. Besides, the key regulators of ferroptosis exhibit aberrant m6A levels under different pathological conditions. However, the correlation between m6A-modified ferroptosis and multiple diseases has not been well elucidated. In this review, we summarized the functions of m6A in ferroptosis, which are associated with the initiation and progression of multiple diseases. Investigating the role of m6A in ferroptosis might both facilitate a better understanding of the pathogenesis of these diseases and provide new opportunities for targeted treatment.

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

BACKGROUND

Colorectal cancer (CRC) is the major subtype of gastrointestinal malignancy and involves cancer-related genes and signaling pathways to regulate ferroptosis. The present study was conducted to analyze the role of alkB homolog 5 (ALKBH5) in the ferroptosis of CRC cells and provide novel targets for CRC treatment.

METHODS

The transcriptional and protein levels of ALKBH5 and solute carrier family 7 members 11 (SLC7A11) in tissues and cells were determined by qRT-PCR and Western blot assay. HCT116 and SW620 cells were transfected with ALKBH5 overexpression vectors to determine cell viability and levels of reactive oxygen species (ROS), Fe⁺, glutathione, and glutathione peroxidase 4 using cell counting kit-8, colony formation, fluorescence probe, assay kits, and Western blot assay. The N6-methyladenosine (m6A) level and the enrichment of m6A on SLC7A11 mRNA were measured by m6A quantitative analysis and m6A methylated RNA immunoprecipitation-qPCR, and the mRNA stability was determined after actinomycin D treatment. CRC cells were treated with the combination of SLC7A11 and ALKBH5 overexpression vectors to confirm the mechanism. Nude mice were subcutaneously injected with CRC cells overexpressing ALKBH5.

RESULTS

ALKBH5 was downregulated in CRC and ALKBH5 overexpression promoted ROS release and ferroptosis. ALKBH5 erased the m6A modification on SLC7A11 mRNA to reduce the mRNA stability of SLC7A11, further reducing SLC7A11 expression. SLC7A11 overexpression reversed the promotive role of ALKBH5 overexpression in ferroptosis. ALKBH5 upregulation mitigated tumor growth in vivo.

CONCLUSIONS

ALKBH5 reduced SLC7A11 transcription by erasing m6A modification, thus promoting the ferroptosis of CRC cells.