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

Biological roles of enhancer RNA m6A modification and its implications in cancer

Enhancers, as distal cis-regulatory elements in the genome, have a pivotal influence on orchestrating precise gene expression. Enhancer RNAs (eRNAs), transcribed from active enhancer regions, are increasingly recognized as key regulators of transcription. N6-methyladenosine (m6A), the most plentiful internal modification in eukaryotic mRNAs, has garnered significant research interest in recent years. With advancements in high-throughput sequencing technologies, it has been established that m6A modifications are also present on eRNAs. An accumulative body of evidence demonstrates that aberrant enhancers, eRNAs, and m6A modifications are intimately connected with carcinoma onset, progression, invasion, metastasis, treatment response, drug resistance, and prognosis. However, the underlying molecular mechanisms governing m6A modification of eRNAs in cancer remain elusive. Here, we review and synthesize current understanding of the regulatory roles of enhancers, eRNAs, and m6A modifications in cancer. Furthermore, we investigate the possible roles of eRNAs m6A modification in tumorigenesis based on existing literature, offering novel perspectives and directions for future research on epigenetic regulatory mechanisms in cancer cells.

Ferroptosis: Therapeutic Potential and Strategies in Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer and a leading cause of cancer-related morbidity and mortality worldwide. Despite advancements in therapeutic strategies, the prognosis for NSCLC patients remains unfavorable. The effective treatment of NSCLC remains challenging due to its aggressive metastatic and invasive properties. Therefore, there is an urgent need to explore novel treatment strategies. In recent years, different from apoptosis and necrosis, ferroptosis has garnered increasing attention since its initial identification in 2012. It is increasingly recognized as a key factor in the development and progression of various cancers. In this review, we summarize the distinctive morphological and biochemical characteristics of ferroptosis and its regulatory mechanisms. Furthermore, we discuss the genetic regulation of ferroptosis in NSCLC, highlighting key biomarkers that may serve as potential therapeutic targets. We also evaluate emerging therapeutic strategies targeting ferroptosis, including gene therapy, natural compounds, chemical agents, combination therapies, and nanoparticle-based approaches. Based on current evidence, the limitations and future prospects of ferroptosis-based therapies for NSCLC are discussed. This review aims to provide novel insights into the potential of ferroptosis-based therapies for NSCLC and its implications for the development of novel treatments.

Summary of the mechanism of ferroptosis regulated by m6A modification in cancer progression

The most common form of internal RNA modification in eukaryotes is called n6-methyladenosine (m6A) methylation. It has become more and more well-known as a research issue in recent years since it alters RNA metabolism and is involved in numerous biological processes. Currently, m6A alteration offers new opportunities in clinical applications and is intimately linked to carcinogenesis. Ferroptosis-a form of iron-dependent, lipid peroxidation-induced regulated cell death-was discovered. In the development of cancer, it has become an important factor. According to newly available data, ferroptosis regulates tumor growth, and cancer exhibits aberrant m6A levels in crucial ferroptosis regulatory components. On the other hand, m6A has multiple roles in the development of tumors, and the relationship between m6A-modified ferroptosis and malignancies is quite intricate. In this review, we first give a thorough review of the regulatory and functional roles of m6A methylation, focusing on the molecular processes of m6A through the regulation of ferroptosis in human cancer progression and metastasis, which are strongly associated to cancer initiation, progression, and drug resistance. Therefore, it is crucial to clarify the relationship between m6A-mediated regulation of ferroptosis in cancer progression, providing a new strategy for cancer treatment with substantial clinical implications.

Integrating bulk and single-cell RNA sequencing data: unveiling RNA methylation and autophagy-related signatures in chronic obstructive pulmonary disease patients

Chronic Obstructive Pulmonary Disease (COPD) is a heterogeneous lung disease influenced by epigenetic modifications, particularly RNA methylation. Emerging evidence also suggests that autophagy plays a crucial role in immune cell infiltration and is implicated in COPD progression. This study aimed to investigate key RNA methylation regulators and explore the roles of RNA methylation and autophagy in COPD pathogenesis. We analyzed tissue-based bulk RNA sequencing and single-cell RNA sequencing (scRNA-seq) datasets from COPD and non-COPD patients, sourced from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified between COPD and non-COPD samples, and protein-protein interaction networks were constructed. Univariate logistic regression identified shared genes between DEGs and RNA methylation gene sets. Functional enrichment analyses, including Gene Ontology (GO), gene set enrichment analysis (GSEA), and gene set variation analysis (GSVA), were performed. Weighted gene co-expression network analysis (WGCNA) and immune infiltration analysis were conducted. Integration with scRNA-seq data further elucidated changes in immune cell composition, and cell communication analysis assessed interactions between macrophages and other immune cells. AddModuleScore analysis quantified RNA methylation and autophagy effects. Finally, a COPD mouse model was used to validate the expression of critical RNA methylation genes (FTO and IGF2BP2) in lung macrophages via RT-qPCR and flow cytometry. As revealed, we identified 13 RNA methylation-related genes enriched in translation and methylation processes. GSEA and GSVA revealed significant enrichment of these genes in immune and autophagy pathways. WGCNA analysis pinpointed key hub genes linking RNA methylation and autophagy. Integrated scRNA-seq analysis demonstrated a marked reduction of macrophages in COPD, with FTO and IGF2BP2 emerging as critical RNA methylation regulators. Macrophages with elevated RNA methylation and autophagy scores had increased interactions with other immune cells. In COPD mouse models, decreased expression of FTO and IGF2BP2 in lung macrophages was validated. Taken together, this study highlights the significant roles of RNA methylation in relation to autophagy pathways in the context of COPD. We identified key RNA methylation-related hub genes, such as FTO and IGF2BP2, which were found to have decreased expression in COPD macrophages. These findings provide novel genetic insights into the epigenetic mechanisms of COPD and suggest potential avenues for developing diagnostic and therapeutic strategies.

Cis-Regulation of an m6A Eraser by an Insertion Variant Associated with Survival of Patients With Non-Small Cell Lung Carcinoma

N6-methyladenosine (m6A) serves as one of the crucial RNA modifications for genes involved in cancer progression. Here, 7273 expression quantitative trait loci potentially regulating 30 m6A pathway genes are identified from the GTEx database, with 69 single nucleotide polymorphisms significantly associated with survival of non-small cell lung carcinoma (NSCLC) patients (n = 1523) from the ongoing genome-wide association study after false positive probability tests. Notably, the rs151198415 locus, situated in a potential enhancer region, demonstrated a prolonged survival effect with the C>CCACG insertion, which is validated in an independent prospective cohort (n = 237), yielding a pooled hazard ratio of 0.72 (p = 0.007). Mechanistically, the rs151198415 C>CCACG insertion engaged in long-range interaction with the promoter of m6A eraser ALKBH5, promoting ALKBH5 transcription by the creation of an EGR1 binding site. Then, ALKBH5 upregulated FBXL5 expression by m6A demethylation, which is dependent on the ALKBH5 H204 amino acid site and specific m6A sites on FBXL5 mRNA. Finally, the ALKBH5-FBXL5 axis reduces intracellular reactive oxygen species levels, leading to PI3K/AKT and NF-kB pathway inhibition and consequently suppresses NSCLC proliferation and metastasis in vitro and in vivo. Triggered by an insertion variant, this remote cis-regulation of m6A eraser and the downstream molecular events modulate the survival of NSCLC patients.

ALKBH5 insufficiency protects against ferroptosis-driven cisplatin-induced renal cytotoxicity

In the clinical setting, cisplatin-induced nephrotoxicity primarily manifests as acute kidney injury (AKI). Recent studies have indicated that ferroptosis, a type of iron-dependent cell death, is closely involved in the cisplatin nephrotoxicity. AlkB homologue 5 (ALKBH5), an N6-methyladenosine (m6A) eraser protein expressed in various tissues, including the kidneys, has been implicated in this process. However, the specific role of ALKBH5 in cisplatin-induced nephrotoxicity remains unknown. Our findings indicated that ALKBH5 was upregulated in cisplatin-induced AKI, and the in vivo study results were consistent with the results of the in vitro study. Additionally, ALKBH5 knockout in transgenic animals was found to mitigate cisplatin-induced renal dysfunction, whereas its knock-in exacerbated the effects. Our study revealed that ALKBH5 controls the traditional ferroptosis metabolic pathway, leading to worsening of AKI in experiments conducted both in vivo and in vitro. The efficacy of pharmacological intervention targeting ALKBH5 in AKI animal models was demonstrated, and ALKBH5-based gene therapy confirmed these findings and displayed renoprotective effects against AKI. In conclusion, this study highlighted the crucial role of ALKBH5 as a key regulator of AKI. Overall, our research demonstrates the significant impact of ALKBH5 in controlling ferroptosis in cisplatin-induced AKI, suggesting that focusing on ALKBH5 could be a promising approach for treating cisplatin-related kidney damage.

RNA m6A modification in ferroptosis: implications for advancing tumor immunotherapy

The pursuit of innovative therapeutic strategies in oncology remains imperative, given the persistent global impact of cancer as a leading cause of mortality. Immunotherapy is regarded as one of the most promising techniques for systemic cancer therapies among the several therapeutic options available. Nevertheless, limited immune response rates and immune resistance urge us on an augmentation for therapeutic efficacy rather than sticking to conventional approaches. Ferroptosis, a novel reprogrammed cell death, is tightly correlated with the tumor immune environment and interferes with cancer progression. Highly mutant or metastasis-prone tumor cells are more susceptible to iron-dependent nonapoptotic cell death. Consequently, ferroptosis-induction therapies hold the promise of overcoming resistance to conventional treatments. The most prevalent post-transcriptional modification, RNA m6A modification, regulates the metabolic processes of targeted RNAs and is involved in numerous physiological and pathological processes. Aberrant m6A modification influences cell susceptibility to ferroptosis, as well as the expression of immune checkpoints. Clarifying the regulation of m6A modification on ferroptosis and its significance in tumor cell response will provide a distinct method for finding potential targets to enhance the effectiveness of immunotherapy. In this review, we comprehensively summarized regulatory characteristics of RNA m6A modification on ferroptosis and discussed the role of RNA m6A-mediated ferroptosis on immunotherapy, aiming to enhance the effectiveness of ferroptosis-sensitive immunotherapy as a treatment for immune-resistant malignancies.