Ferroptosis in Lung Cancer: From Molecular Mechanisms to Prognostic and Therapeutic Opportunities

Inducing ferroptosis by traditional medicines: a novel approach to reverse chemoresistance in lung cancer

Lung cancer is the leading cause of global cancer-related deaths. Platinum-based chemotherapy is the first-line treatment for the most common type of lung cancer, i.e., non-small-cell lung cancer (NSCLC), but its therapeutic efficiency is limited by chemotherapeutic resistance. Therefore, it is vital to develop effective therapeutic modalities that bypass the common molecular mechanisms associated with chemotherapeutic resistance. Ferroptosis is a form of non-apoptotic regulated cell death characterized by iron-dependent lipid peroxidation (LPO). Ferroptosis is crucial for the proper therapeutic efficacy of lung cancer-associated chemotherapies. If targeted as a novel therapeutic mechanism, ferroptosis modulators present new opportunities for increasing the therapeutic efficacy of lung cancer chemotherapy. Emerging studies have revealed that the pharmacological induction of ferroptosis using natural compounds boosts the efficacy of chemotherapy in lung cancer or drug-resistant cancer. In this review, we first discuss chemotherapeutic resistance (or chemoresistance) in lung cancer and introduce the core mechanisms behind ferroptosis. Then, we comprehensively summarize the small-molecule compounds sourced from traditional medicines that may boost the anti-tumor activity of current chemotherapeutic agents and overcome chemotherapeutic resistance in NSCLC. Cumulatively, we suggest that traditional medicines with ferroptosis-related anticancer activity could serve as a starting point to overcome chemotherapeutic resistance in NSCLC by inducing ferroptosis, highlighting new potential therapeutic regimens used to overcome chemoresistance in NSCLC.

SLC7A11 inhibits ferroptosis and downregulates PD-L1 levels in lung adenocarcinoma

Introduction

Lung adenocarcinoma (LUAD) is a prevalent form of lung cancer originating from lung glandular cells with low survival rates despite recent therapeutic advances due to its diverse and complex nature. Recent evidence suggests a link between ferroptosis and the effectiveness of anti-PD-L1 therapy, with potential synergistic effects.

Methods

Our study comprehensively analyzed the expression patterns of ferroptosis regulators in LUAD and their association with prognosis and PD-L1 expression. Furthermore, we identified two distinct subtypes of LUAD through consensus clustering of ferroptosis regulators, revealing significant tumor heterogeneity, divergent PD-L1 expression, and varying prognoses between the subtypes.

Results

Among the selected ferroptosis regulators, SLC7A11 emerged as an independent prognostic marker for LUAD patients and exhibited a negative correlation with PD-L1 expression. Subsequent investigations revealed high expression of SLC7A11 in the LUAD population. In vitro experiments demonstrated that overexpression of SLC7A11 led to reduced PD-L1 expression and inhibited ferroptosis in A549 cells, underscoring the significant role of SLC7A11 in LUAD. Additionally, pan-cancer analyses indicated an association between SLC7A11 and the expression of immune checkpoint genes across multiple cancer types with poor prognoses.

Discussion

From a clinical standpoint, these findings offer a foundation for identifying and optimizing potential combination strategies to enhance the therapeutic effectiveness of immune checkpoint inhibitors and improve the prognosis of patients with LUAD.

Ferroptosis in lung cancer: dual role, multi-level regulation, and new therapeutic strategies

Lung cancer is a highly prevalent malignant tumor worldwide, with high incidence and death rates. Recently, there has been increasing recognition of the role of ferroptosis, a unique cell death mechanism, in lung cancer. This review aims to summarize the current research progress on the relationship between ferroptosis and lung cancer. It also provides a comprehensive analysis of the regulatory processes of ferroptosis in various stages, including epigenetics, transcription, post-transcription, translation, and post-translation. Additionally, the review explores the dual nature of ferroptosis in lung cancer progression, which presents interesting therapeutic possibilities. On one hand, ferroptosis can promote the escape of immune surveillance and reduce the efficacy of treatment in the early stages of tumors. On the other hand, it can counter drug resistance, enhance radiosensitivity, and promote immunotherapy. The article also discusses various combination treatment strategies based on the mechanism of ferroptosis. Overall, this review offers a holistic perspective on the role of ferroptosis in the onset, progression, and treatment of lung cancer. It aims to contribute to future research and clinical interventions in this field.

Ferroptosis-related exosomal non-coding RNAs: promising targets in pathogenesis and treatment of non-malignant diseases

Ferroptosis, an iron-dependent form of programmed cell death, introduces a novel perspective on cellular demise. This study investigates the regulatory network of exosomal non-coding RNAs (ncRNAs), including miRNAs, circRNAs, and lncRNAs, in ferroptosis modulation. The primary goal is to examine the pathological roles of ferroptosis-related exosomal ncRNAs, particularly in ischemic reperfusion injuries. The research reveals intricate molecular interactions governing the regulatory interplay between exosomal ncRNAs and ferroptosis, elucidating their diverse roles in different non-malignant pathological contexts. Attention is given to their impact on diseases, including cardiac, cerebral, liver, and kidney ischemic injuries, as well as lung, wound, and neuronal injuries. Beyond theoretical exploration, the study provides insights into potential therapeutic applications, emphasizing the significance of mesenchymal stem cells (MSCs)-derived exosomes. Findings underscore the pivotal role of MSC-derived exosomal ncRNAs in modulating cellular responses related to ferroptosis regulation, introducing a cutting-edge dimension. This recognition emphasizes the importance of MSC-derived exosomes as crucial mediators with broad therapeutic implications. Insights unveil promising avenues for targeted interventions, capitalizing on the diverse roles of exosomal ncRNAs, providing a comprehensive foundation for future therapeutic strategies.

Prognostic Value of hsa_circ_0007615 in Epithelial Ovarian Cancer and its Regulatory Effect on Tumor Progression

This study aimed to interrogate the functional and clinical significance of hsa_circ_0007615 in epithelial ovarian cancer (EOC). GSE192410 was screened for upregulated circRNAs in ovarian cancer. The expression levels of hsa_circ_0007615 were evaluated in a patient cohort comprising 113 EOC tissues and matched normal tissues. Subsequently, the prognostic value was confirmed by the relevance of hsa_circ_0007615 with clinical parameters, Kaplan-Meier analysis and Cox proportional risk model. Cell functional analyses were performed in EOC cell lines using a cell proliferation kit, transwell and cell death kit. Our data revealed that hsa_circ_0007615 was significantly upregulated in EOC tissues and cell lines, compared with normal ones. Multivariate survival analysis revealed that hsa_circ_0007615 emerged as an independent risk factor for overall survival and recurrence of EOC patients. Knockdown of hsa_circ_0007615 in EOC cells led to the blocking of cell proliferation, migration and invasion, but an increase of cell death presenting as ferroptosis. Tumor suppressive effects of hsa_circ_0007615 knockdown can be abolished by miR-874-3p inhibition. TUBB3 was a targeting gene of miR-874-3p. Hsa_circ_0007615 has the functional and clinical significance of EOC. Mechanistically, hsa_circ_0007615 may contribute to EOC by sponging miR-874-3p and moderating TUBB3.

A review on the research progress of traditional Chinese medicine with anti-cancer effect targeting ferroptosis

Ferroptosis is a non-apoptotic form of regulated cell death characterized by iron-dependent lipid peroxidation. It can be triggered by various mechanisms, including the glutathione peroxidase 4 (GPX4)-glutathione (GSH) axis, iron metabolism, lipid metabolism, the GTP cyclohydrolase 1 (GCH1)-tetrahydrobiopterin (BH4) pathway, and the ferroptosis suppressor protein 1 (FSP1)-coenzyme Q10 axis. The redox balance is disrupted when ferroptosis occurs in cells, which is fatal to cancer cells. Additionally, some tumor-associated genes are involved in ferroptosis. Hence, targeting ferroptosis might be an effective strategy for treating cancer. Several small-molecule compounds exhibit anti-tumor effects through ferroptosis, including sorafenib and altretamine, which induce ferroptosis by inhibiting System-Xc and GPX4 respectively, but many problems, such as poor druggability, still exist. Some studies have shown that many traditional Chinese medicine (TCM) induce ferroptosis by inhibiting GPX4, solute carrier family 7 member 11 (SLC7A11), and nuclear factor (erythroid-derived 2)-like 2 (Nrf2), or by increasing the expression of Acyl-CoA synthetase long-chain family member 4 (ACSL4), transferrin (TF), and transferrin receptor 1 (TFR1). These changes can lead to the lysosomal degradation of ferritin, accumulation of iron, lipid peroxidation and the production of reactive oxygen species (ROS), which in turn can promote anti-tumor activities or synergistic effects with chemotherapeutic drugs. In this study, we elucidated the underlying mechanisms of ferroptosis, and the anti-tumor pharmacology of TCM targeting ferroptosis including prescriptions, Chinese herbs, extracts, and natural compounds. Our findings might act as valuable reference for research on anti-tumor drugs targeting ferroptosis, especially those drugs developed from TCM.

Mutation of TP53 Confers Ferroptosis Resistance in Lung Cancer Through the FOXM1/MEF2C Axis

Ferroptosis is a highly regulated tumor suppressor process. Loss or mutation of TP53 can cause changes in sensitivity to ferroptosis. Mutations in TP53 may be associated with the malignant or indolent progression of ground glass nodules in early lung cancer, but whether ferroptosis may also be involved in determining this biological process has not yet been determined. Using in vivo and in vitro gain- and loss-of-function approaches, this study used clinical tissue for mutation analysis and pathological research to show that wild-type TP53 inhibited the expression of forkhead box M1 (FOXM1) by binding to peroxisome proliferator-activated receptor-γ coactivator 1α, maintaining the mitochondrial function and thus affecting the sensitivity to ferroptosis. This function was absent in mutant cells, resulting in overexpression of FOXM1 and ferroptosis resistance. Mechanistically, FOXM1 activated the transcription level of myocyte-specific enhancer factor 2C in the mitogen-activated protein kinase signaling pathway, leading to stress protection when exposed to ferroptosis inducers. This study provides new insights into the mechanism of association between TP53 mutation and ferroptosis tolerance, which can aid a deeper understanding of the role of TP53 in the malignant progression of lung cancer.

Roles, biological functions, and clinical significances of RHPN1-AS1 in cancer

For the complex and multifaceted challenge of cancer eradication, a comprehensive approach is required. Molecular strategies are critical in the fight against cancer as they allow us to understand the underlying fundamental mechanisms and develop specialized treatments. The role of long non-coding RNAs (lncRNAs), a class of ncRNA molecules longer than 200 nucleotides, in cancer biology has attracted growing attention in recent years. These roles include but are not limited to regulating gene expression, protein localization, and chromatin remodeling. LncRNAs can influence a range of cellular functions and pathways, including those involved in cancer development. The first study on RHPN1 antisense RNA 1 (RHPN1-AS1), a 2030-bp transcript originating from human chromosome 8q24, in uveal melanoma (UM) demonstrated that this lncRNA was significantly upregulated in several UM cell lines. Further studies in various cancer cell lines showed that this lncRNA is significantly overexpressed and exerts oncogenic functions. This review will provide an overview of current knowledge regarding the roles played by RHPN1-AS1 in the emergence of various cancers, focusing on its biological and clinical functions.

Ferroptosis as a potential target for cancer therapy

Ferroptosis is a recently discovered essential type of cell death that is mainly characterized by iron overload and lipid peroxidation. Emerging evidence suggests that ferroptosis is a double-edged sword in human cancer. However, the precise underlying molecular mechanisms and their differential roles in tumorigenesis are unclear. Therefore, in this review, we summarize and briefly present the key pathways of ferroptosis, paying special attention to the regulation of ferroptosis as well as its dual role as an oncogenic and as a tumor suppressor event in various human cancers. Moreover, multiple pharmacological ferroptosis activators are summarized, and the prospect of targeting ferroptosis in cancer therapy is further elucidated.

Proteogenomic characterization of ferroptosis regulators reveals therapeutic potential in glioblastoma

BACKGROUND

Ferroptosis is iron-dependent non-apoptotic cell death, that is characterized by the excessive accumulation of lipid peroxides. Ferroptosis-inducing therapy also shows promise in the treatment of cancers. However, ferroptosis-inducing therapy for glioblastoma multiforme (GBM) is still in the exploratory stage.

METHODS

We identified the differentially expressed ferroptosis regulators using Mann-Whitney U test in the proteome data from Clinical Proteomic Tumor Analysis Consortium (CPTAC). We next analyzed the effect of mutation on protein abundance. A multivariate Cox model was constructed to identify the prognostic signature.

RESULTS

In this study, we systemically portrayed the proteogenomic landscape of ferroptosis regulators in GBM. We observed that some mutation-specific ferroptosis regulators, such as down-regulated ACSL4 in EGFR-mutated patients and up-regulated FADS2 in IDH1-mutated patients, were linked to the inhibited ferroptosis activity in GBM. To interrogate the valuable treatment targets, we performed the survival analysis and identified five ferroptosis regulators (ACSL3, HSPB1, ELAVL1, IL33, and GPX4) as the prognostic biomarkers. We also validated their efficiency in external validation cohorts. Notably, we found overexpressed protein and phosphorylation abundances of HSPB1 were poor prognosis markers for overall survival of GBM to inhibit ferroptosis activity. Alternatively, HSPB1 showed a significant association with macrophage infiltration levels. Macrophage-secreted SPP1 could be a potential activator for HSPB1 in glioma cells. Finally, we recognized that ipatasertib, a novel pan-Akt inhibitor, could be a potential drug for suppressing HSPB1 phosphorylation, inducing ferroptosis of glioma cells.

CONCLUSION

In summary, our study characterized the proteogenomic landscape of ferroptosis regulators and identified that HSPB1 could be a candidate target for ferroptosis-inducing therapy strategy for GBM.

Overcoming cancer chemotherapy resistance by the induction of ferroptosis

Development of resistance to chemotherapy in cancer continues to be a major challenge in cancer management. Ferroptosis, a unique type of cell death, is mechanistically and morphologically different from other forms of cell death. Ferroptosis plays a pivotal role in inhibiting tumour growth and has presented new opportunities for treatment of chemotherapy-insensitive tumours in recent years. Emerging studies have suggested that ferroptosis can regulate the therapeutic responses of tumours. Accumulating evidence supports ferroptosis as a potential target for chemotherapy resistance. Pharmacological induction of ferroptosis could reverse drug resistance in tumours. In this review article, we first discuss the key principles of chemotherapeutic resistance in cancer. We then provide a brief overview of the core mechanisms of ferroptosis in cancer chemotherapeutic drug resistance. Finally, we summarise the emerging data that supports the fact that chemotherapy resistance in different types of cancers could be subdued by pharmacologically inducing ferroptosis. This review article suggests that pharmacological induction of ferroptosis by bioactive compounds (ferroptosis inducers) could overcome chemotherapeutic drug resistance. This article also highlights some promising therapeutic avenues that could be used to overcome chemotherapeutic drug resistance in cancer.

Ferroptosis in osteosarcoma: A promising future

The incidence of osteosarcoma (OS) is increasing year by year, and the prognosis of patients with advanced OS is extremely poor due to the tendency of recurrence and chemotherapy resistance after surgery. Ferroptosis is a novel form of programmed cell death (PCD) that kills cells through iron-dependent lipid peroxidation. Current studies have shown that ferroptosis is closely related to OS and could reduce chemotherapy resistance to a certain extent, which has great therapeutic potential. In this paper, we review the regulatory mechanism of ferroptosis and its research progress in OS, hoping to provide new help for the clinical treatment of OS.

OIT3 serves as a novel biomarker of hepatocellular carcinoma by mediating ferroptosis via regulating the arachidonic acid metabolism

Background

Oncoprotein-Induced Transcript 3 Protein (OIT3) was identified as a liver-specific gene with abnormal expression in hepatocellular carcinoma (HCC). Herein, we aimed to examine the function and specific mechanism of OIT3 in HCC.

Methods

Bioinformatic analyses and tissue microarray via immunohistochemistry were used to validate the expression of OIT3 in HCC. The biofunctions of OIT3 in HCC were determined in vitro and in vivo. The mechanism was confirmed by RNA-Sequence and Western blotting. The uni- and multivariate analyses were used to identify the independent predictors for HCC.

Results

Low expression of OIT3 was observed in HCC and predicted a poor clinical outcome. Ectopic expression of OIT3 could inhibit the proliferation, migration, and invasion abilities of HCC cells. Mechanistically, OIT3 upregulated the expression of ALOX15 and CYP4F3, thus inducing arachidonic acid increase, ROS accumulation, and lipid peroxidation, and eventually causing ferroptosis. OIT3 was validated as a prognostic predictor for HCC patients.

Conclusions

Our findings revealed a novel role of OIT3 in the process of tumorigenesis of HCC. OIT3 inhibited reproliferation, migration, and invasion of HCC cells by triggering ferroptosis, which indicates that OIT3 could serve as a potential biomarker in HCC.

Ferroptosis: A Specific Vulnerability of RAS-Driven Cancers?

Ferroptosis has emerged as a new type of programmed cell death that can be harnessed for cancer therapy. The concept of ferroptosis was for the first time proposed in in the early 2000s, as an iron-dependent mode of regulated cell death caused by unrestricted lipid peroxidation (LPO) and subsequent plasma membrane rupture. Since the discovery and characterization of ferroptosis, a wealth of research has improved our understanding of the main pathways regulating this process, leading to both the repurposing and the development of small molecules.

However, ferroptosis is still little understood and several aspects remain to be investigated. For instance, it is unclear whether specific oncogenes, cells of origin or tumor niches impose specific susceptibility/resistance to ferroptosis or if there are some ferroptosis-related genes that may be used as bona fide pan-cancer targetable dependencies. In this context, even though RAS-driven cancer cell lines seemed to be selectively sensitive to ferroptosis inducers, subsequent studies have questioned these results, indicating that in some cases mutant RAS is necessary, but not sufficient to induce ferroptosis. In this perspective, based on publicly available genomic screening data and the literature, we discuss the relationship between RAS-mutation and ferroptosis susceptibility in cancer.

Multifaceted Roles of Ferroptosis in Lung Diseases

Ferroptosis is a distinct type of programmed cell death (PCD) that depends on iron and is characterized by the accumulation of intracellular iron, exhaustion of glutathione, deactivation of glutathione peroxidase, and promotion of lipid peroxidation. Recently, accumulated investigations have demonstrated that ferroptosis is strongly correlated with the initiation and development of many lung diseases. In this review, we summarized the contribution of ferroptosis to the pathologic process of lung diseases, namely, obstructive lung diseases (chronic obstructive pulmonary disease, asthma, and cystic fibrosis), interstitial lung diseases (pulmonary fibrosis of different causes), pulmonary diseases of vascular origin (ischemia-reperfusion injury and pulmonary hypertension), pulmonary infections (bacteria, viruses, and fungi), acute lung injury, acute respiratory distress syndrome, obstructive sleep apnea, pulmonary alveolar proteinosis, and lung cancer. We also discussed the therapeutic potential of targeting ferroptosis for these lung diseases.

Gracillin Shows Potential Efficacy Against Non-Small Cell Lung Cancer Through Inhibiting the mTOR Pathway

The leading cause of cancer deaths is lung cancer, non-small cell lung cancer (NSCLC), the most common type of lung cancers, remains a difficult cancer to treat and cure. It is urgent to develop new products to treat NSCLS. Gracillin, extracted from Reineckia carnea, Dioscorea villosa, and other medicinal plants, has anti-tumor potential with toxic effect on a variety of tumor cells such as NSCLC. However, the anti-NSCLC mechanism of gracillin is not completely clear. In this study, A549 cells and athymic nude mice were used as models to evaluate the anti-NSCLC effects of gracillin. The antiproliferative activity of gracillin on A549 cells was conducted by CCK-8, and obvious autophagy was observed in gracillin-treated A549 through transmission electron microscopy. Furthermore, the expressions of Beclin-1, LC3-II, and WIPI1 were upregulated, while the expression of p62 was downregulated in gracillin-treated A549. The further mechanism study found that the mTOR signaling pathway was significantly inhibited by gracillin. Accordingly, the PI3K/Akt pathway positively regulating mTOR was inhibited, and AMPK negatively regulating mTOR was activated. Meanwhile, LC3-II transformation was found to be significantly reduced after WIPI1 was silenced in A549 cells but increased after gracillin treatment. It also proves that WIPI is involved in the process of gracillin regulating A549 autophagy. At last, the anti-tumor growth activity of gracillin in vivo was validated in A549-bearing athymic nude mice. In conclusion, gracillin has anti-NSCLC activity by inducing autophagy. The mechanism maybe that gracillin inhibited the mTOR signaling pathway. Gracillin has the potential to be a candidate product for the treatment of NSCLC in the future.