CircRNA-ST6GALNAC6 increases the sensitivity of bladder cancer cells to erastin-induced ferroptosis by regulating the HSPB1/P38 axis

Therapeutic importance and diagnostic function of circRNAs in urological cancers: from metastasis to drug resistance

Circular RNAs (circRNAs) are a member of non-coding RNAs with no ability in encoding proteins and their aberrant dysregulation is observed in cancers. Their closed-loop structure has increased their stability, and they are reliable biomarkers for cancer diagnosis. Urological cancers have been responsible for high mortality and morbidity worldwide, and developing new strategies in their treatment, especially based on gene therapy, is of importance since these malignant diseases do not respond to conventional therapies. In the current review, three important aims are followed. At the first step, the role of circRNAs in increasing or decreasing the progression of urological cancers is discussed, and the double-edged sword function of them is also highlighted. At the second step, the interaction of circRNAs with molecular targets responsible for urological cancer progression is discussed, and their impact on molecular processes such as apoptosis, autophagy, EMT, and MMPs is highlighted. Finally, the use of circRNAs as biomarkers in the diagnosis and prognosis of urological cancer patients is discussed to translate current findings in the clinic for better treatment of patients. Furthermore, since circRNAs can be transferred to tumor via exosomes and the interactions in tumor microenvironment provided by exosomes such as between macrophages and cancer cells is of importance in cancer progression, a separate section has been devoted to the role of exosomal circRNAs in urological tumors.

Research status and potential applications of circRNAs affecting colorectal cancer by regulating ferroptosis

Ferroptosis is an emerging form of non-apoptotic programmed cell death (PCD), characterized by iron-mediated oxidative imbalance. This process plays a significant role in the development and progression of various tumors, including colorectal cancer, gastric cancer, and others. Circular RNA (circRNA) is a stable, non-coding RNA type with a single-stranded, covalently closed loop structure, which is intricately linked to the proliferation, invasion, and metastasis of tumor cells. Recent studies have shown that many circRNAs regulate various pathways leading to cellular ferroptosis. Colorectal cancer, known for its high incidence and mortality among cancers, is marked by a poor prognosis and pronounced chemoresistance. To enhance our understanding of how circRNA-mediated regulation of ferroptosis influences colorectal cancer development, this review systematically examines the mechanisms by which specific circRNAs regulate ferroptosis and their critical role in the progression of colorectal cancer. Furthermore, it explores the potential of circRNAs as biomarkers and therapeutic targets in colorectal cancer treatment, offering a novel approach to clinical management.

CircVPS8 promotes the malignant phenotype and inhibits ferroptosis of glioma stem cells by acting as a scaffold for MKRN1, SOX15 and HNF4A

Exciting breakthroughs have been achieved in the field of glioblastoma with therapeutic interventions targeting specific ferroptosis targets. Nonetheless, the precise mechanisms through which circRNAs regulate the ferroptosis pathway have yet to be fully elucidated. Here we have identified a novel circRNA, circVPS8, which is highly expressed in glioblastoma. Our findings demonstrated that circVPS8 enhances glioma stem cells' viability, proliferation, sphere-forming ability, and stemness. Additionally, it inhibits ferroptosis in GSCs. In vivo, experiments further supported the promotion of glioblastoma growth by circVPS8. Mechanistically, circVPS8 acts as a scaffold, binding to both MKRN1 and SOX15, thus facilitating the ubiquitination of MKRN1 and subsequent degradation of SOX15. Due to competitive binding, the ubiquitination ability of MKRN1 towards HNF4A is reduced, leading to elevated HNF4A expression. Increased HNF4A expression, along with decreased SOX15 expression, synergistically inhibits ferroptosis in glioblastoma. Overall, our study highlights circVPS8 as a promising therapeutic target and provides valuable insights for clinically targeted therapy of glioblastoma.

Expression of transferrin receptor/TFRC protein in bladder cancer cell T24 and its role in inducing iron death in bladder cancer

Bladder cancer (BC) is a very common malignant tumor in the urinary system. However, the incidence rate, recurrence rate, progression rate and metastasis rate of bladder cancer are still very high, leading to poor long-term prognosis of patients. This study was to investigate the expression of transferrin receptor/TFRC protein in bladder cancer tissue and its role in inducing iron death of T24 human bladder cancer cells. Based on the intersection of 259 FerrDb genes in the iron death database with GSE13507 and GSE13167 data sets, 54 genes related to iron death in bladder cancer were obtained. Analyzing 54 genes, KEGG enrichment analysis showed that the pathways involved were mainly focused on iron death, autophagy, and tumor center carbon metabolism. GO analysis found that the molecular functions mainly gather in ubiquitin like protein ligase binding, ubiquitin protein ligase binding, and antioxidant activity. In the cellular components, it is mainly distributed in pigment granules, melanosomes, and the basal lateral plasma membrane. In biological processes, it is enriched in nutrient level responses, responses to extracellular stimuli, and cellular redox homeostasis. Screen out the top 10 core genes. The 10 core genes are SLC2A1, TFRC, EGFR, KRAS, CAV1, HSPA5, NFE2L2, VEGFA, PIK3CA, and HRAS. Finally, TFRC was selected as the research object. TCGA analysis showed that the expression level in bladder cancer tissue was higher than that in normal tissue, and the difference was statistically significant (P < 0.001). Conclusion (1) TFRC is highly expressed in many kinds of tumors, and it is more highly expressed in bladder cancer than in normal bladder tissue. (2) TFRC has certain diagnostic and prognostic value in bladder cancer. (3) Erastin, an iron death inducer, induced the iron death of T24 human bladder cancer cells, knocked down the expression of TFRC in T24 human bladder cancer cells, and preliminarily verified that silencing TFRC could inhibit the iron death of T24 human bladder cancer cells.

Mitochondria-targeting peptide SS-31 attenuates ferroptosis via inhibition of the p38 MAPK signaling pathway in the hippocampus of epileptic rats

Ferroptosis is a newly identified form of non-apoptotic regulated cell death (RCD) andplaysanimportantrole in epileptogenesis. The p38 mitogen-activated protein kinase (p38 MAPK) pathway has been confirmed to be involved in ferroptosis. The mitochondria-targeting antioxidant Elamipretide (SS-31) can reduce the generation of lipid peroxidation and the buildup of reactive oxygen species (ROS). Collectively, our present study was to decipher whether SS-31 inhibits ferroptosis via the p38 MAPK signaling pathway in the rat epilepsy model induced by pilocarpine (PILO).Adult male Wistar rats were randomly divided into four groups: control group (CON group), epilepsy group (EP group), SS-31 treatment group (SS group), and p38 MAPK inhibitor (SB203580) treatment group (SB group). Our results demonstrated that the rat hippocampal neurons after epilepsy were followed by accumulated iron and malondialdehyde (MDA) content, upregulated phosphorylated p38 MAPK protein (P-p38) and nuclear factor erythroid 2-related factor 2 (Nrf2) levels, reduced glutathione peroxidase 4 (Gpx4) content, and depleted glutathione (GSH) activity. Morphologically, mitochondrial ultrastructural damage under electron microscopy was manifested by a partial increase in outer membrane density, disappearance of mitochondrial cristae, and mitochondrial shrinkage. SS-31 and SB203580 treatment blocked the initiation and progression of ferroptosis in the hippocampus of epileptic rats via reducing the severity of epileptic seizures, reversing the expression of Gpx4, P-p38 , decreasing the levels of iron and MDA, as well as increasing the activity of GSH and Nrf2. To summarize, our findings proved that ferroptosis was coupled with the pathology of epilepsy, and SS-31 can inhibit PILO-induced seizures by preventing ferroptosis, which may be connected to the inhibition of p38 MAPK phosphorylation, highlighting the potential therapeutic value for targeting ferroptosis process in individuals with seizure-related diseases.

Effects of ferroptosis-related gene HSPB1 on acute myeloid leukemia

INTRODUCTION

The purpose of this study was to investigate the effects and potential mechanisms of ferroptosis-related gene heat shock protein beta-1 (HSPB1) on acute myeloid leukemia (AML).

METHODS

The RNA-seq and clinical data of AML samples were obtained from the Genomic Data Commons database, and the FerrDb database was used to screen the marker, drive and suppressor of ferroptosis. Besides, DESeq2 was applied for differential expression analysis on AML samples and screening for differentially expressed genes (DEGs). The screened DEGs were subjected to the intersection analysis with ferroptosis-related genes to identify the ferroptosis-related DEGs. Next, the functional pathways of ferroptosis-related DEGs were further be discussed by Gene Ontology as well as Kyoto Encyclopedia of Genes and Genomes enrichment analysis of DEGs. Additionally, lasso regression analysis was employed to determine the differential genes related to prognosis in patients with AML and the survival analysis was performed. Subsequently, quantitative real-time polymerase chain reaction and western blot assay were applied to detect the mRNA and protein expression levels of HSPB1 in normal/AML bone marrow tissues and human normal (HS-5)/AML (HL-60) bone marrow cells, respectively. Furthermore, HSPB1 was knocked down to assess the expression changes of glutathione peroxidase 4 and acyl-CoA synthetase long-chain family member 4. Ultimately, the viability and oxidative stress levels of HL-60 were analyzed by Cell Counting Kit-8 and biochemical detection.

RESULTS

A total of 4986 DEGs were identified in AML samples, with 3324 up-regulated and 1662 down-regulated. The enrichment analysis illustrated that ferroptosis-related DEGs were significantly enriched in response to metal irons, oxidative stress, and other pathways. After lasso regression analysis, 17 feature genes related to the prognosis of patients with AML were obtained, with HSPB1 exhibiting a significant correlation. The reliability of our models was verified by Cox regression analysis and survival analysis of the hazard model. Furthermore, the outcomes of quantitative real-time polymerase chain reaction and western blot showed that mRNA and protein expression levels of HSPB1 were significantly increased in the AML Group and HL-60 cells. The knockdown of HSPB1 in HL-60 cells reduced the protein level of glutathione peroxidase 4, increased the protein level of acyl-CoA synthetase long-chain family member 4, decreased the cell viability, and aggravated oxidative stress.

CONCLUSION

Ferroptosis-related gene HSPB1 is highly expressed in patients with AML. In addition, HSPB1 may be involved in the occurrence and development of AML by regulating oxidative stress and ferroptosis-related pathways. This study provides new clues for further understanding of AML molecular mechanisms. Also, HSPB1 is expected to be a potential therapeutic target for AML in the future.

Exosomal HSPB1, interacting with FUS protein, suppresses hypoxia-induced ferroptosis in pancreatic cancer by stabilizing Nrf2 mRNA and repressing P450

Ferroptosis is a new type of programmed cell death, which has been involved in the progression of tumours. However, the regulatory network of ferroptosis in pancreatic cancer is still largely unknown. Here, using datasets from GEO and TCGA, we screened HSPB1, related to the P450 monooxygenase signalling, a fuel of ferroptosis, to be a candidate gene for regulating pancreatic cancer cell ferroptosis. We found that HSPB1 was enriched in the exosomes derived from human pancreatic cancer cell lines SW1990 and Panc-1. Then, hypoxic SW1990 cells were incubated with exosomes alone or together with HSPB1 siRNA (si-HSPB1), and we observed that exosomes promoted cell proliferation and invasion and suppressed ferroptosis, which was reversed by si-HSPB1. Moreover, we found a potential binding affinity between HSPB1 and FUS, verified their protein interaction by using dual-colour fluorescence colocalization and co-IP assays, and demonstrated the promoting effect of FUS on oxidative stress and ferroptosis in hypoxic SW1990 cells. Subsequently, FUS was demonstrated to bind with and stabilize the mRNA of Nrf2, a famous anti-ferroptosis gene that negatively regulates the level of P450. Furthermore, overexpressing FUS and activating the Nrf2/HO-1 pathway (using NK-252) both reversed the inhibitory effect of si-HSPB1 on exosome functions. Finally, our in vivo studies showed that exosome administration promote tumour growth in nude mice of xenotransplantation, which was able to be eliminated by knockdown of HSPB1. In conclusion, exosomal HSPB1 interacts with the RNA binding protein FUS and decreases FUS-mediated stability of Nrf2 mRNA, thus suppressing hypoxia-induced ferroptosis in pancreatic cancer.

Ferroptosis and circular RNAs: new horizons in cancer therapy

Cancer poses intricate challenges to treatment due to its complexity and diversity. Ferroptosis and circular RNAs (circRNAs) are emerging as innovative therapeutic avenues amid the evolving landscape of cancer therapy. Extensive investigations into circRNAs reveal their diverse roles, ranging from molecular regulators to pivotal influencers of ferroptosis in cancer cell lines. The results underscore the significance of circRNAs in modulating molecular pathways that impact crucial aspects of cancer development, including cell survival, proliferation, and metastasis. A detailed analysis delineates these pathways, shedding light on the molecular mechanisms through which circRNAs influence ferroptosis. Building upon recent experimental findings, the study evaluates the therapeutic potential of targeting circRNAs to induce ferroptosis. By identifying specific circRNAs associated with the etiology of cancer, this analysis paves the way for the development of targeted therapeutics that exploit vulnerabilities in cancer cells. This review consolidates the existing understanding of ferroptosis and circRNAs, emphasizing their role in cancer therapy and providing impetus for ongoing research in this dynamic field. See also the graphical abstract(Fig. 1).

The potential role and mechanism of circRNAs in Ferroptosis: A comprehensive review

Cell death encompasses various mechanisms, including necrosis and apoptosis. Ferroptosis, a unique form of regulated cell death, emerged as a non-apoptotic process reliant on iron and reactive oxygen species (ROS). Distinguishing itself from other forms of cell death, ferroptosis exhibits distinct morphological, biochemical, and genetic features. Circular RNAs (circRNAs), a novel class of RNA molecules, play crucial regulatory roles in ferroptosis-mediated pathways and cellular processes. With their circular structure and stability, circRNAs function as microRNA sponges and participate in protein regulation, offering diverse mechanisms for cellular control. Accumulating evidence indicates that circRNAs are key players in diseases associated with ferroptosis, presenting opportunities for diagnostic and therapeutic applications. This study explores the regulatory roles of circRNAs in ferroptosis and their potential in diseases such as cancer, neurological disorders, and cardiovascular diseases. By investigating the relationship between circRNAs and ferroptosis, this research provides new insights into the diagnosis, treatment, and prognosis of ferroptosis-related diseases. Furthermore, the therapeutic implications of targeting circRNAs in cancer treatment and the modulation of ferroptosis pathways demonstrate the potential of circRNAs as diagnostic markers and therapeutic targets. Overall, understanding the involvement of circRNAs in regulating ferroptosis opens up new avenues for advancements in disease management.

Current and Potential Roles of Ferroptosis in Bladder Cancer

Ferroptosis, a type of regulated cell death driven by iron-dependent lipid peroxidation, is mainly initiated by extramitochondrial lipid peroxidation due to the accumulation of iron-dependent reactive oxygen species. Ferroptosis is a prevalent and primitive form of cell death. Numerous cellular metabolic processes regulate ferroptosis, including redox homeostasis, iron regulation, mitochondrial activity, amino acid metabolism, lipid metabolism, and various disease-related signaling pathways. Ferroptosis plays a pivotal role in cancer therapy, particularly in the eradication of aggressive malignancies resistant to conventional treatments. Multiple studies have explored the connection between ferroptosis and bladder cancer, focusing on its incidence and treatment outcomes. Several biomolecules and tumor-associated signaling pathways, such as p53, heat shock protein 1, nuclear receptor coactivator 4, RAS-RAF-MEK, phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin, and the Hippo-tafazzin signaling system, exert a moderating influence on ferroptosis in bladder cancer. Ferroptosis inducers, including erastin, artemisinin, conjugated polymer nanoparticles, and quinazolinyl-arylurea derivatives, hold promise for enhancing the effectiveness of conventional anticancer medications in bladder cancer treatment. Combining conventional therapeutic drugs and treatment methods related to ferroptosis offers a promising approach for the treatment of bladder cancer. In this review, we analyze the research on ferroptosis to augment the efficacy of bladder cancer treatment.

Circular RNAs in Breast Cancer: An Update

Breast cancer (BC), characterized by high heterogeneity, is the most commonly reported malignancy among females across the globe. Every year, many BC patients die owing to delayed diagnosis and treatment. Increasing researches have indicated that aberrantly expressed circular RNAs (circRNAs) are implicated in the tumorigenesis and progression of various tumors, including BC. Hence, this article provides a summary of the biogenesis and functions of circRNAs, as well as an examination of how circRNAs regulate the progression of BC. Moreover, circRNAs have aroused incremental attention as potential diagnostic and prognostic biomarkers for BC. Exosomes enriched with circRNAs can be secreted into the tumor microenvironment to mediate intercellular communication, affecting the progression of BC. Detecting the expression levels of exosomal circRNAs may provide reference for BC diagnosis and prognosis prediction. Illuminating insights into the earlier diagnosis and better treatment regimens of BC will be potentially available following elucidation of deeper regulatory mechanisms of circRNAs in this malignancy.

circPVT1 Inhibits the Proliferation and Aids in Prediction of the Prognosis of Bladder Cancer

Background

Circular RNA PVT1 (circPVT1) is aberrantly expressed in several cancers, but its functional role and clinical relevance in bladder urothelial carcinoma (BLCA) remain unknown. This study aimed to identify the expression level of circPVT1 in BLCA and investigated its functional relevance with BLCA progression both in vitro and in vivo.

Methods

GEPIA, UALCAN, and OncoLnc were referred to presented data. Quantitative real-time PCR (qPCR) was used for the measurement of transnational expression of genes in BLCA specimens and cell lines. Immunohistochemistry (IHC) and fluorescence in situ hybridization analysis (FISH) assays were performed to detect HER2 amplification, Pearson's correlation analysis to analyze the correlation between circPVT1 expression and clinical characteristics, Cox regression and K-M survival analyses to analyze prognostic factors. A nomogram was constructed for predicting prognosis. The proliferation of cells was measured by CCK-8 and colony formation assay, and the proliferation in vivo was evaluated using nude mouse models. qPCR was used to detect the expression of proliferation-related genes.

Results

circPVT1 was but mRNA PVT1 was not significantly overexpressed in BLCA. A high circPVT1 expression was associated with a better survival and negative HER2, but not with age, gender, and T stage. circPVT1 was an independent prognostic factor for the overall survival of BLCA patients. Knocking down circPVT1 promoted BLCA proliferation in vitro and in vivo. Knocking down circPVT1 upregulated ERBB2, MKI67, and PCNA expression and downregulated TP53 expression, but exerted no influence on CCND1 and CCNB1 expression.

Conclusion

circPVT1 is a tumor suppressor and novel prognostic biomarker for BLCA.

Mechanisms of immune checkpoint inhibitors: insights into the regulation of circular RNAS involved in cancer hallmarks

Current treatment strategies for cancer, especially advanced cancer, are limited and unsatisfactory. One of the most substantial advances in cancer therapy, in the last decades, was the discovery of a new layer of immunotherapy approach, immune checkpoint inhibitors (ICIs), which can specifically activate immune cells by targeting immune checkpoints. Immune checkpoints are a type of immunosuppressive molecules expressed on immune cells, which can regulate the degree of immune activation and avoid autoimmune responses. ICIs, such as anti-PD-1/PD-L1 drugs, has shown inspiring efficacy and broad applicability across various cancers. Unfortunately, not all cancer patients benefit remarkably from ICIs, and the overall response rates to ICIs remain relatively low for most cancer types. Moreover, the primary and acquired resistance to ICIs pose serious challenges to the clinical application of cancer immunotherapy. Thus, a deeper understanding of the molecular biological properties and regulatory mechanisms of immune checkpoints is urgently needed to improve clinical options for current therapies. Recently, circular RNAs (circRNAs) have attracted increasing attention, not only due to their involvement in various aspects of cancer hallmarks, but also for their impact on immune checkpoints in shaping the tumor immune microenvironment. In this review, we systematically summarize the current status of immune checkpoints in cancer and the existing regulatory roles of circRNAs on immune checkpoints. Meanwhile, we also aim to settle the issue in an evidence-oriented manner that circRNAs involved in cancer hallmarks regulate the effects and resistance of ICIs by targeting immune checkpoints.

Modulation of ferroptosis by non‑coding RNAs in cancers: Potential biomarkers for cancer diagnose and therapy

Ferroptosis is a recently discovered cell programmed death. Extensive researches have indicated that ferroptosis plays an essential role in tumorigenesis, development, migration and chemotherapy drugs resistance, which makes it become a new target for tumor therapy. Non-coding RNAs (ncRNAs) are considered to control a wide range of cellular processes by modulating gene expression. Recent studies have indicated that ncRNAs regulate the process of ferroptosis via various pathway to affect the development of cancer. However, the regulation network remains ambiguous. In this review, we outlined the major metabolic processes of ferroptosis and concluded the relationship between ferroptosis-related ncRNAs and cancer progression. In addition, the prospect of ncRNAs being new therapeutic targets and early diagnosis biomarkers for cancer by regulating ferroptosis were presented, and the possible obstacles were also predicted. This could help in discovering novel cancer early diagnostic methods and therapeutic approaches.

Musashi-2 Deficiency Triggers Colorectal Cancer Ferroptosis by Downregulating the MAPK Signaling Cascade to Inhibit HSPB1 Phosphorylation

BACKGROUND

Musashi-2 (MSI2) is a critical RNA-binding protein (RBP) whose ectopic expression drives the pathogenesis of various cancers. Accumulating evidence suggests that inducing ferroptosis of tumor cells can inhibit their malignant biological behavior as a promising therapeutic approach. However, it is unclear whether MSI2 regulates cell death in colorectal cancer (CRC), especially the underlying mechanisms and biological effects in CRC ferroptosis remain elusive.

METHODS

Experimental methods including qRT‒PCR, immunofluorescence, flow cytometry, western blot, co-immunoprecipitation, CCK-8, colony formation assay, in vitro cell transwell migration and invasion assays, in vivo xenograft tumor experiments, liver and lung CRC metastasis models, CAC mice models, transmission electron microscopy, immunohistochemistry, histopathology, 4D label-free proteomics sequencing, bioinformatic and database analysis were used in this study.

RESULTS

Here, we investigated that MSI2 was upregulated in CRC and positively correlated with ferroptosis inhibitor molecules. MSI2 deficiency suppressed CRC malignancy by inhibiting cell proliferation, viability, migration and invasion in vitro and in vivo; and MSI2 deficiency triggered CRC ferroptosis by changing the intracellular redox state (ROS levels and lipid peroxidation), erastin induced cell mortality and viability, iron homeostasis (intracellular total irons and ferrous irons), reduced glutathione (GSH) levels and mitochondrial injury. Mechanistically, through 4D-lable free proteomics analysis on SW620 stable cell lines, we demonstrated that MSI2 directly interacted with p-ERK and MSI2 knockdown downregulated the p-ERK/p38/MAPK axis signaling pathway, which further repressed MAPKAPK2 and HPSB1 phosphorylation, leading to decreased expression of PCNA and Ki67 and increased expression of ACSL4 in cancer cells. Furthermore, HSPB1 could rescue the phenotypes of MSI2 deficiency on CRC ferroptosis in vitro and in vivo.

CONCLUSIONS

This study indicates that MSI2 deficiency suppresses the growth and survival of CRC cells and promotes ferroptosis by inactivating the MAPK signaling pathway to inhibit HSPB1 phosphorylation, which leads to downregulation of PCNA and Ki67 and upregulation of ACSL4 in cancer cells and subsequently induces redox imbalance, iron accumulation and mitochondrial shrinkage, ultimately triggering ferroptosis. Therefore, targeted inhibition of MSI2/MAPK/HSPB1 axis to promote ferroptosis might be a potential treatment strategy for CRC.

CircRNA and ferroptosis in human disease: Insights for new treatments

Circular RNA (circRNA), classified as a type of non-coding RNA, has gained significant attention in the field of biology due to its distinctive ring structure and functional properties. Recent research has provided evidence that specific circRNAs have the ability to modulate disease progression through diverse mechanisms, one of which is by regulating cellular ferroptosis. Ferroptosis is a form of regulated cell death that is driven by iron dependency and lipid peroxidation, and extensive investigations have revealed a relationship between ferroptosis and disease development. In addition to evidence that both circRNAs and ferroptosis exert critical roles in disease progression, circRNAs have also been shown to actively mediate the process of ferroptosis. The relationship between circRNAs and ferroptosis therefore influences disease progression and offers novel targets for disease treatment. By directly or indirectly modulating the expression of circRNAs that regulate the expression of ferroptosis-related proteins, it may be possible to impact disease progression by promoting or inhibiting ferroptosis. Current research indicates such approaches may hold significant value in a wide variety of common diseases across physiological systems. This review comprehensively summarizes the findings of recent studies investigating the roles of circRNAs in the regulation of ferroptosis in various diseases.

FHOD1 is upregulated in glioma cells and attenuates ferroptosis of glioma cells by targeting HSPB1 signaling

BACKGROUND

As a new type of regulatory cell death, ferroptosis has been proven to be involved in cancer pathogenesis and therapeutic response. However, the detailed roles of ferroptosis or ferroptosis-associated genes in glioma remain to be clarified.

METHODS

Here, we performed the TMT/iTRAQ-Based Quantitative Proteomic Approach to identify the differentially expressed proteins between glioma specimens and adjacent tissues. Kaplan-Meier survival was used to estimate the survival values. We also explored the regulatory roles of abnormally expressed formin homology 2 domain-containing protein 1 (FHOD1) in glioma ferroptosis sensitivity.

RESULTS

In our study, FHOD1 was identified to be the most significantly upregulated protein in glioma tissues. Multiple glioma datasets revealed that the glioma patients with low FHOD1 expression displayed favorable survival time. Functional analysis proved that the knockdown of FHOD1 inhibited cell growth and improved the cellular sensitivity to ferroptosis in glioma cells T98G and U251. Mechanically, we found the up-regulation and hypomethylation of HSPB1, a negative regulator of ferroptosis, in glioma tissues. FHOD1 knockdown could enhance the ferroptosis sensitivity of glioma cells via up-regulating the methylated heat-shock protein B (HSPB1). Overexpression of HSPB1 significantly reversed FHOD1 knockdown-mediated ferroptosis.

CONCLUSIONS

In summary, this study demonstrated that the FHOD1-HSPB1 axis exerts marked regulatory effects on ferroptosis, and might affect the prognosis and therapeutic response in glioma.

Ferroptosis: An Emerging Target for Bladder Cancer Therapy

Bladder cancer (BC), as one of the main urological cancers in the world, possesses the abilities of multiple-drug resistance and metastasis. However, there remains a significant gap in the understanding and advancement of prognosis and therapeutic strategies for BC. Ferroptosis, a novel type of iron-dependent regulated cell death, depends on lipid peroxidation, which has been proven to have a strong correlation with the development and treatment of BC. Its mechanism mainly includes three pathways, namely, lipid peroxidation, the antioxidant system, and the iron overload pathway. In this review, we reviewed the mechanism of ferroptosis, along with the related therapeutic targets and drugs for BC, as it might become a new anticancer treatment in the future.

CircRNF10 triggers a positive feedback loop to facilitate progression of glioblastoma via redeploying the ferroptosis defense in GSCs

BACKGROUND

Glioma exhibit heterogeneous susceptibility for targeted ferroptosis. How circRNAs alterations in glioma promote iron metabolism and ferroptosis defense remains unclarified.

METHODS

The highly enriched circRNAs in glioblastoma (GBM) were obtained through analysis of sequencing datasets. Quantitative real-time PCR (qRT-PCR) was used to determine the expression of circRNF10 in glioma and normal brain tissue. Both gain-of-function and loss-of-function studies were used to assess the effects of circRNF10 on ferroptosis using in vitro and in vivo assays. The hypothesis that ZBTB48 promotes ferroptosis defense was established using bioinformatics analysis and functional assays. RNA pull-down and RNA immunoprecipitation (RIP) assays were performed to examine the interaction between circRNF10 and target proteins including ZBTB48, MKRN3 and IGF2BP3. The posttranslational modification mechanism of ZBTB48 was verified using coimmunoprecipitation (co-IP) and ubiquitination assays. The transcription activation of HSPB1 and IGF2BP3 by ZBTB48 was confirmed through luciferase reporter gene and chromatin immunoprecipitation (ChIP) assays. The stabilizing effect of IGF2BP3 on circRNF10 was explored by actinomycin D assay. Finally, a series of in vivo experiments were performed to explore the influences of circRNF10 on the glioma progression.

RESULTS

A novel circular RNA, hsa_circ_0028912 (named circRNF10), which is significantly upregulated in glioblastoma tissues and correlated with patients' poor prognosis. Through integrated analysis of the circRNA-proteins interaction datasets and sequencing results, we reveal ZBTB48 as a transcriptional factor binding with circRNF10, notably promoting upregulation of HSPB1 and IGF2BP3 expression to remodel iron metabolism and facilitates the launch of a circRNF10/ZBTB48/IGF2BP3 positive feedback loop in GSCs. Additionally, circRNF10 can competitively bind to MKRN3 and block E3 ubiquitin ligase activity to enhance ZBTB48 expression. Consequently, circRNF10-overexpressed glioma stem cells (GSCs) display lower Fe2+ accumulation, selectively priming tumors for ferroptosis evading.

CONCLUSION

Our research presents abnormal circRNAs expression causing a molecular and metabolic change of glioma, which we leverage to discover a therapeutically exploitable vulnerability to target ferroptosis.

Non-coding RNAs in lung cancer: molecular mechanisms and clinical applications

Lung cancer (LC) is a heterogeneous disease with high malignant degree, rapid growth, and early metastasis. The clinical outcomes of LC patients are generally poor due to the insufficient elucidation of pathological mechanisms, low efficiency of detection and assessment methods, and lack of individualized therapeutic strategies. Non-coding RNAs (ncRNAs), including microRNA (miRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA), are endogenous regulators that are widely involved in the modulation of almost all aspects of life activities, from organogenesis and aging to immunity and cancer. They commonly play vital roles in various biological processes by regulating gene expression via their interactions with DNA, RNA, or protein. An increasing amount of studies have demonstrated that ncRNAs are closely correlated with the initiation and development of LC. Their dysregulation promotes the progression of LC via distinct mechanisms, such as influencing protein activity, activating oncogenic signaling pathways, or altering specific gene expression. Furthermore, some ncRNAs present certain clinical values as biomarker candidates and therapeutic targets for LC patients. A complete understanding of their mechanisms in LC progression may be highly beneficial to developing ncRNA-based therapeutics for LC patients. This review mainly focuses on the intricate mechanisms of miRNA, lncRNA, and circRNA involved in LC progression and discuss their underlying applications in LC treatment.

Noncoding RNAs in cancer ferroptosis: From biology to clinical opportunity

Ferroptosis is a recently discovered pattern of programmed cell death that is nonapoptotic and irondependent. It is involved in lipid peroxidation dependent on reactive oxygen species. Ferroptosis has been verified to play a crucial regulatory role in a variety of pathological courses of disease, in particularly cancer. Emerging research has highlighted the potential of ferroptosis in tumorigenesis, cancer development and resistance to chemotherapy. However, the regulatory mechanism of ferroptosis remains unclear, which limits the application of ferroptosis in cancer treatment. Noncoding RNAs (ncRNAs) are noncoding transcripts that regulate gene expression in various ways to affect the malignant phenotypes of cancer cells. At present, the biological function and underlying regulatory mechanism of ncRNAs in cancer ferroptosis have been partially elucidated. Herein, we summarize the current knowledge of the central regulatory network of ferroptosis, with a focus on the regulatory functions of ncRNAs in cancer ferroptosis. The clinical application and prospects of ferroptosis-related ncRNAs in cancer diagnosis, prognosis and anticancer therapies are also discussed. Elucidating the function and mechanism of ncRNAs in ferroptosis, along with assessing the clinical significance of ferroptosis-related ncRNAs, provides new perspectives for understanding cancer biology and treatment approaches, which may benefit numerous cancer patients in the future.

The Regulation of Ferroptosis by Noncoding RNAs

As a novel form of regulated cell death, ferroptosis is characterized by intracellular iron and lipid peroxide accumulation, which is different from other regulated cell death forms morphologically, biochemically, and immunologically. Ferroptosis is regulated by iron metabolism, lipid metabolism, and antioxidant defense systems as well as various transcription factors and related signal pathways. Emerging evidence has highlighted that ferroptosis is associated with many physiological and pathological processes, including cancer, neurodegeneration diseases, cardiovascular diseases, and ischemia/reperfusion injury. Noncoding RNAs are a group of functional RNA molecules that are not translated into proteins, which can regulate gene expression in various manners. An increasing number of studies have shown that noncoding RNAs, especially miRNAs, lncRNAs, and circRNAs, can interfere with the progression of ferroptosis by modulating ferroptosis-related genes or proteins directly or indirectly. In this review, we summarize the basic mechanisms and regulations of ferroptosis and focus on the recent studies on the mechanism for different types of ncRNAs to regulate ferroptosis in different physiological and pathological conditions, which will deepen our understanding of ferroptosis regulation by noncoding RNAs and provide new insights into employing noncoding RNAs in ferroptosis-associated therapeutic strategies.

Functional Diversity of Mammalian Small Heat Shock Proteins: A Review

The small heat shock proteins (sHSPs), whose molecular weight ranges from 12∼43 kDa, are members of the heat shock protein (HSP) family that are widely found in all organisms. As intracellular stress resistance molecules, sHSPs play an important role in maintaining the homeostasis of the intracellular environment under various stressful conditions. A total of 10 sHSPs have been identified in mammals, sharing conserved α-crystal domains combined with variable N-terminal and C-terminal regions. Unlike large-molecular-weight HSP, sHSPs prevent substrate protein aggregation through an ATP-independent mechanism. In addition to chaperone activity, sHSPs were also shown to suppress apoptosis, ferroptosis, and senescence, promote autophagy, regulate cytoskeletal dynamics, maintain membrane stability, control the direction of cellular differentiation, modulate angiogenesis, and spermatogenesis, as well as attenuate the inflammatory response and reduce oxidative damage. Phosphorylation is the most significant post-translational modification of sHSPs and is usually an indicator of their activation. Furthermore, abnormalities in sHSPs often lead to aggregation of substrate proteins and dysfunction of client proteins, resulting in disease. This paper reviews the various biological functions of sHSPs in mammals, emphasizing the roles of different sHSPs in specific cellular activities. In addition, we discuss the effect of phosphorylation on the function of sHSPs and the association between sHSPs and disease.

Exosomal circRNA: emerging insights into cancer progression and clinical application potential

Exosomal circRNA serves a novel genetic information molecule, facilitating communication between tumor cells and microenvironmental cells, such as immune cells, fibroblasts, and other components, thereby regulating critical aspects of cancer progression including immune escape, tumor angiogenesis, metabolism, drug resistance, proliferation and metastasis. Interestingly, microenvironment cells have new findings in influencing tumor progression and immune escape mediated by the release of exosomal circRNA. Given the intrinsic stability, abundance, and broad distribution of exosomal circRNAs, they represent excellent diagnostic and prognostic biomarkers for liquid biopsy. Moreover, artificially synthesized circRNAs may open up new possibilities for cancer therapy, potentially bolstered by nanoparticles or plant exosome delivery strategies. In this review, we summarize the functions and underlying mechanisms of tumor cell and non-tumor cell-derived exosomal circRNAs in cancer progression, with a special focus on their roles in tumor immunity and metabolism. Finally, we examine the potential application of exosomal circRNAs as diagnostic biomarkers and therapeutic targets, highlighting their promise for clinical use.

Roles of non-coding RNAs in the metabolism and pathogenesis of bladder cancer

Bladder cancer (BC) is featured as the second most common malignancy of the urinary tract worldwide with few treatments leading to high incidence and mortality. It stayed a virtually intractable disease, and efforts to identify innovative and effective therapies are urgently needed. At present, more and more evidence shows the importance of non-coding RNA (ncRNA) for disease-related study, diagnosis, and treatment of diverse types of malignancies. Recent evidence suggests that dysregulated functions of ncRNAs are closely associated with the pathogenesis of numerous cancers including BC. The detailed mechanisms underlying the dysregulated role of ncRNAs in cancer progression are still not fully understood. This review mainly summarizes recent findings on regulatory mechanisms of the ncRNAs, long non-coding RNAs, microRNAs, and circular RNAs, in cancer progression or suppression and focuses on the predictive values of ncRNAs-related signatures in BC clinical outcomes. A deeper understanding of the ncRNA interactive network could be compelling framework for developing biomarker-guided clinical trials.

Andrographolide induced ferroptosis in multiple myeloma cells by regulating the P38/Nrf2/HO-1 pathway

Andrographis paniculata is used as a functional food in Asia. Andrographolide (Andro), a diterpene lactone isolated from Andrographis paniculata, has been reported to have potent anticancer activity. Multiple myeloma (MM), the second most common malignant tumor in hematology, is incurable. Ferroptosis, a type of cell death driven by iron-dependent lipid peroxidation, has shown potential in the treatment of various cancers. However, previous studies have not demonstrated whether Andro inhibits the development of MM via ferroptosis or any other mechanism. In the present study, we observed that Andro induced cell death, G0/G1 cell cycle arrest and evoked oxidative stress in MM cells. Interestingly, these phenomena were accompanied by increases in intracellular and mitochondrial Fe²⁺ and lipid peroxidation levels. Furthermore, treatment with ferroptosis inhibitors rescued Andro-induced cell death, which indicated that ferroptosis contributed to this phenomenon. Mechanistic examination showed that Andro may block the Nrf2/HO-1 signaling pathway by activating P38, thereby inducing ferroptosis. Moreover, inhibition of P38 expression rescued Andro-induced cell death, changes in the level of Nrf2 and HO-1 expression, Fe²⁺ and lipid peroxidation. Taken together, our findings suggest that Andro induces ferroptosis in MM cells via the P38/Nrf2/HO-1 pathway, providing a potential preventative and therapeutic approach for MM.

Enhancing Vulnerability of Afatinib using Erastin via xCT-mediated ROS/P38MAPK Signaling Feedback Loop in Gastric Cancer Cells

Ferroptosis, being classified as a form of regulated cell death, was driven by the oxidative injury induced by lipid peroxidation(LPO). Recently, ferroptosis has been confirmed to exert a critical effect in the pathogenesis and treatment of various tumors, including gastric cancer (GC). Erastin, as a frequently used ferroptosis inducer, caused ferroptosis by downregulating the xCT expression resulting in increasing reactive oxygen species (ROS) and aggravating the LPO. However, the mechanisms of Erastin in ferroptosis regulation, especially in GC, remain largely elusive. This work firstly demonstrated that Erastin inhibited cell growth and promoted apoptosis and ferroptosis in AGS and BGC823 cells. Then, based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of Erastin-related targets screened by using PharmMapper Web, the P38MAPK signaling was explored and validated in AGS and BGC-823 cells. Besides, the Fer-1 and p38 inhibitor were performed to investigate the mechanisms of ferroptosis induced by Erastin in depth. This work revealed a feedback mode among xCT, ROS and the P38MAPK pathway, which affected each other. It meant that Erastin regulated ferroptosis through the xCT-mediated ROS/P38MAPK signaling feedback loop. In addition, it was noticed that in co-operation with Erastin, the cytotoxic effects of Afatinib on cells were aggravated by further strengthening ferroptosis with activation of the P38MAPK pathway. In summary, those works provided evidence that Erastin plays an important role in increasing the cytotoxic effect on GC cells treated with Afitinib. Furthermore, the Erastin-induced ferroptosis via the xCT-mediated ROS/P38MAPK pathway feedback loop provides new strategies for GC comprehensive treatment.

Regulation of ncRNAs involved with ferroptosis in various cancers

As a special pattern of programmed cell death, ferroptosis is reported to participate in several processes of tumor progression, including regulating proliferation, suppressing apoptotic pathways, increasing metastasis, and acquiring drug resistance. The marked features of ferroptosis are an abnormal intracellular iron metabolism and lipid peroxidation that are pluralistically modulated by ferroptosis-related molecules and signals, such as iron metabolism, lipid peroxidation, system Xc−, GPX4, ROS production, and Nrf2 signals. Non-coding RNAs (ncRNAs) are a type of functional RNA molecules that are not translated into a protein. Increasing studies demonstrate that ncRNAs have a diversity of regulatory roles in ferroptosis, thus influencing the progression of cancers. In this study, we review the fundamental mechanisms and regulation network of ncRNAs on ferroptosis in various tumors, aiming to provide a systematic understanding of recently emerging non-coding RNAs and ferroptosis.

Regulatory roles of ferroptosis-related non-coding RNAs and their research progress in urological malignancies

Ferroptosis is a new type of cell death characterized by damage to the intracellular microenvironment, which causes the accumulation of lipid hydroperoxide and reactive oxygen species to cause cytotoxicity and regulated cell death. Non-coding RNAs (ncRNAs) play an important role in gene expression at the epigenetic, transcriptional, and post-transcriptional levels through interactions with different DNAs, RNAs, or proteins. Increasing evidence has shown that ferroptosis-related ncRNAs are closely related to the occurrence and progression of several diseases, including urological malignancies. Recently, the role of ferroptosis-associated ncRNAs (long non-coding RNAs, micro RNAs, and circular RNAs) in the occurrence, drug resistance, and prognosis of urological malignancies has attracted widespread attention. However, this has not yet been addressed systematically. In this review, we discuss this issue as much as possible to expand the knowledge and understanding of urological malignancies to provide new ideas for exploring the diagnosis and treatment of urological malignancies in the future. Furthermore, we propose some challenges in the clinical application of ferroptosis-associated ncRNAs.

Identification and validation of hub genes and potential drugs involved in osteoarthritis through bioinformatics analysis

Purpose: Osteoarthritis (OA) is a common degenerative disease, which still lacks specific therapeutic drugs. Synovitis is one of the most important pathological process in OA. Therefore, we aim to identify and analyze the hub genes and their related networks of OA synovium with bioinformatics tools to provide theoretical basis for potential drugs. Materials and methods: Two datasets were obtained from GEO. DEGs and hub genes of OA synovial tissue were screened through Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment as well as protein-protein interaction (PPI) network analysis. Subsequently, the correlation between expression of hub genes and ferroptosis or pyroptosis was analyzed. CeRNA regulatory network was constructed after predicting the upstream miRNAs and lncRNAs. The validation of hub genes was undertook through RT-qPCR and ELISA. Finally, potential drugs targeting pathways and hub genes were identified, followed by the validation of the effect of two potential drugs on OA. Results: A total of 161 commom DEGs were obtained, of which 8 genes were finally identified as hub genes through GO and KEGG enrichment analysis as well as PPI network analysis. Eight genes related to ferroptosis and pyroptosis respectively were significantly correlated to the expression of hub genes. 24 miRNAs and 69 lncRNAs were identified to construct the ceRNA regulatory network. The validation of EGR1, JUN, MYC, FOSL1, and FOSL2 met the trend of bioinformatics analysis. Etanercept and Iguratimod reduced the secretion of MMP-13 and ADAMTS5 of fibroblast-like synoviocyte. Conclusion: EGR1, JUN, MYC, FOSL1, and FOSL2 were identified as hub genes in the development of OA after series of bioinformatics analysis and validation. Etanercept and Iguratimod seemed to have opportunities to be novel drugs for OA.

Ferroptosis-associated circular RNAs: Opportunities and challenges in the diagnosis and treatment of cancer

Ferroptosis is an emerging form of non-apoptotic regulated cell death which is different from cell death mechanisms such as autophagy, apoptosis and necrosis. It is characterized by iron-dependent lipid peroxide accumulation. Circular RNA (circRNA) is a newly studied evolutionarily conserved type of non-coding RNA with a covalent closed-loop structure. It exhibits universality, conservatism, stability and particularity. At present, the functions that have been studied and found include microRNA sponge, protein scaffold, transcription regulation, translation and production of peptides, etc. CircRNA can be used as a biomarker of tumors and is a hotspot in RNA biology research. Studies have shown that ferroptosis can participate in tumor regulation through the circRNA molecular pathway and then affect cancer progression, which may become a direction of cancer diagnosis and treatment in the future. This paper reviews the molecular biological mechanism of ferroptosis and the role of circular RNA in tumors and summarizes the circRNA related to ferroptosis in tumors, which may inspire research prospects for the precise prevention and treatment of cancer in the future.

The Mutual Relationship between Glycosylation and Non-Coding RNAs in Cancer and Other Physio-Pathological Conditions

Glycosylation, which consists of the enzymatic addition of sugars to proteins and lipids, is one of the most important post-co-synthetic modifications of these molecules, profoundly affecting their activity. Although the presence of carbohydrate chains is crucial for fine-tuning the interactions between cells and molecules, glycosylation is an intrinsically stochastic process regulated by the relative abundance of biosynthetic (glycosyltransferases) and catabolic (glycosidases) enzymes, as well as sugar carriers and other molecules. Non-coding RNAs, which include microRNAs, long non-coding RNAs and circRNAs, establish a complex network of reciprocally interacting molecules whose final goal is the regulation of mRNA expression. Likewise, these interactions are stochastically regulated by ncRNA abundance. Thus, while protein sequence is deterministically dictated by the DNA/RNA/protein axis, protein abundance and activity are regulated by two stochastic processes acting, respectively, before and after the biosynthesis of the protein axis. Consequently, the worlds of glycosylation and ncRNA are closely interconnected and mutually interacting. In this paper, we will extensively review the many faces of the ncRNA-glycosylation interplay in cancer and other physio-pathological conditions.

Modulation of the p38 MAPK Pathway by Anisomycin Promotes Ferroptosis of Hepatocellular Carcinoma through Phosphorylation of H3S10

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor worldwide. Ferroptosis is emerging as an effective target for tumor treatment as it has been shown to potentiate cell death in some malignancies. However, it remains unclear whether histone phosphorylation events, an epigenetic mechanism that regulates transcriptional expression, are involved in ferroptosis. Our study found that supplementation with anisomycin, an agonist of p38 mitogen-activated protein kinase (MAPK), induced ferroptosis in HCC cells, and the phosphorylation of histone H3 on serine 10 (p-H3S10) was participated in anisomycin-induced ferroptosis. To investigate the anticancer effects of anisomycin-activated p38 MAPK in HCC, we analyzed cell viability, colony formation, cell death, and cell migration in Hep3B and HCCLM3 cells. The results showed that anisomycin could significantly suppress HCC cell colony formation and migration and induce HCC cell death. The hallmarks of ferroptosis, such as abnormal accumulation of iron and elevated levels of lipid peroxidation and malondialdehyde, were detected to confirm the ability of anisomycin to promote ferroptosis. Furthermore, coincubation with SB203580, an inhibitor of activated p38 MAPK, partially rescued anisomycin-induced ferroptosis. And the levels of p-p38 MAPK and p-H3S10 were successively increased by anisomycin treatment. The relationship between p-H3S10 and ferroptosis was revealed by ChIP sequencing. The reverse transcription PCR and immunofluorescence results showed that NCOA4 was upregulated both in mRNA and protein levels after anisomycin treatment. And by C11-BODIPY staining, we found that anisomycin-induced lipid reactive oxygen species was reduced after NCOA4 knockdown. In conclusion, the anisomycin-activated p38 MAPK promoted ferroptosis of HCC cells through H3S10 phosphorylation.