Ferroptosis: A New Promising Target for Lung Cancer Therapy

Heavy metals in biological samples of cancer patients: a systematic literature review

The majority of the so-called heavy metals are suspected to be involved in a number of pathologies and play a role in human carcinogenesis. Some of them (i.e. arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg) and nickel (Ni)) have been defined as carcinogens, increasing the susceptibility of tumor development and progression in humans. Moreover, Ni, Cr, Cd, Hg, and Pb together with zinc (Zn) and iron (Fe), may be capable of stimulating the progression of breast cancer and reducing a patient's sensitivity to treatment through alterations to DNA methylation. In patients with gastric cancers, levels of various heavy metals are augmented and hypothesized to amplify the expression of the human epidermal growth factor receptor type 2 gene. Cd may increase the risk of lung cancer development and have a negative impact on the overall survival of lung cancer patients. To investigate the relation between heavy metals in biological samples and risk, occurrence and survival cancer individuals, a comprehensive review work was performed, with a focus on breast, lung, prostate and gastric cancers. An extensive search strategy was devised to ensure relevant literature could be identified, with the PECO framework being adopted to facilitate this and identify key search terms. As evidenced in this review, there is substantial data to support the hypothesis that heavy metals influence tumor development and progression. Unluckily the number of papers dealing with the determination of metals directly in samples from cancer tissues is still rather limited, so we decided to expand the scope of this review also to analyses carried out on other biological samples, as urine, plasma, hair, nail, etc. The studies reviewed showed that several limitations and current knowledge gaps are present in the literature that require further investigation to improve our comprehension of the impact of different heavy metals on tumorigenesis.

GOLPH3 inhibits erastin-induced ferroptosis in colorectal cancer cells

Ferroptosis is a novel form of programmed cell death and is considered to be a druggable target for colorectal cancer (CRC) therapy. However, the role of ferroptosis in CRC and its underlying mechanism are not fully understood. In the present study we found that a protein enriched in the Golgi apparatus, Golgi phosphoprotein 3 (GOLPH3), was overexpressed in human CRC tissue and in several CRC cell lines. The expression of GOLPH3 was significantly correlated with the expression of ferroptosis-related genes in CRC. The overexpression of GOLPH3 in Erastin-induced Caco-2 CRC cells reduced ferroptotic phenotypes, whereas the knockdown of GOLPH3 potentiated ferroptosis in HT-29 CRC cells. GOLPH3 induced the expression of prohibitin-1 (PHB1) and prohibitin-2 (PHB2), which also inhibited ferroptosis in Erastin-treated CRC cells. Moreover, GOLPH3 interacted with PHB2 and nuclear factor erythroid 2-related factor 2 (NRF2) in Caco-2 cells. These observations indicate that GOLPH3 is a negative regulator of ferroptosis in CRC cells. GOLPH3 protects these cells from ferroptosis by inducing the expression of PHB1 and PHB2, and by interacting with PHB2 and NRF2.

Identification of a set of genes potentially responsible for resistance to ferroptosis in lung adenocarcinoma cancer stem cells

Scientific literature supports the evidence that cancer stem cells (CSCs) retain inside low reactive oxygen species (ROS) levels and are, therefore, less susceptible to cell death, including ferroptosis, a type of cell death dependent on iron-driven lipid peroxidation. A collection of lung adenocarcinoma (LUAD) primary cell lines derived from malignant pleural effusions (MPEs) of patients was used to obtain 3D spheroids enriched for stem-like properties. We observed that the ferroptosis inducer RSL3 triggered lipid peroxidation and cell death in LUAD cells when grown in 2D conditions; however, when grown in 3D conditions, all cell lines underwent a phenotypic switch, exhibiting substantial resistance to RSL3 and, therefore, protection against ferroptotic cell death. Interestingly, this phenomenon was reversed by disrupting 3D cells and growing them back in adherence, supporting the idea of CSCs plasticity, which holds that cancer cells have the dynamic ability to transition between a CSC state and a non-CSC state. Molecular analyses showed that ferroptosis resistance in 3D spheroids correlated with an increased expression of antioxidant genes and high levels of proteins involved in iron storage and export, indicating protection against oxidative stress and low availability of iron for the initiation of ferroptosis. Moreover, transcriptomic analyses highlighted a novel subset of genes commonly modulated in 3D spheroids and potentially capable of driving ferroptosis protection in LUAD-CSCs, thus allowing to better understand the mechanisms of CSC-mediated drug resistance in tumors.

Emerging mechanisms of ferroptosis and its implications in lung cancer

ABSTRACT

Lung cancer is one of the most common malignancies and has the highest number of deaths among all cancers. Despite continuous advances in medical strategies, the overall survival of lung cancer patients is still low, probably due to disease progression or drug resistance. Ferroptosis is an iron-dependent form of regulated cell death triggered by the lethal accumulation of lipid peroxides, and its dysregulation is implicated in cancer development. Preclinical evidence has shown that targeting the ferroptosis pathway could be a potential strategy for improving lung cancer treatment outcomes. In this review, we summarize the underlying mechanisms and regulatory networks of ferroptosis in lung cancer and highlight ferroptosis-targeting preclinical attempts to provide new insights for lung cancer treatment.

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.

Ferroptosis in cancer immunity and immunotherapy: Multifaceted interplay and clinical implications

Ferroptosis is a type of cell death characterized by iron-dependent phospholipid peroxidation and reactive oxygen species overproduction. Ferroptosis induces immunogenic cell death and elicits anti-tumor immune responses, playing an important role in cancer immunotherapy. Ferroptosis suppression in cancer cells impairs its immunotherapeutic efficacy. To overcome this issue, ferroptosis inducers (FINs) have been combined with other cancer therapies to create an anti-tumor immune microenvironment. However, the ferroptosis-based crosstalk between immune and tumor cells is complex because oxidative products released by ferroptotic tumor cells impair the functions of anti-tumor immune cells, resulting in immunotherapeutic resistance. In the present article, we have reviewed ferroptosis in tumor and immune cells and summarized the crosstalk between ferroptotic tumor cells and the immune microenvironment. Based on the existing literature, we have further discussed future perspectives on opportunities for combining ferroptosis-targeted therapies with cancer immunotherapies.

Targeting of FSP1 regulates iron homeostasis in drug-tolerant persister head and neck cancer cells via lipid-metabolism-driven ferroptosis

BACKGROUND

Research has demonstrated that some tumor cells can transform into drug-tolerant persisters (DTPs), which serve as a reservoir for the recurrence of the disease. The persister state in cancer cells arises due to temporary molecular reprogramming, and exploring the genetic composition and microenvironment during the development of head and neck squamous cell carcinoma (HNSCC) can enhance our comprehension of the types of cell death that HNSCC, thus identifying potential targets for innovative therapies. This project investigated lipid-metabolism-driven ferroptosis and its role in drug resistance and DTP generation in HNSCC.

METHODS

High levels of FSP1 were discovered in the tissues of patients who experienced relapse after cisplatin treatment. RNA sequencing indicated that a series of genes related to lipid metabolism were also highly expressed in tissues from these patients. Consistent results were obtained in primary DTP cells isolated from patients who experienced relapse. The Cancer Genome Atlas database confirmed this finding. This revealed that the activation of drug resistance in cancer cells is influenced by FSP1, intracellular iron homeostasis, and lipid metabolism. The regulatory roles of ferroptosis suppressor protein 1 (FSP1) in HNSCC metabolic regulation were investigated.

RESULTS

We generated human oral squamous cell carcinoma DTP cells (HNSCC cell line) to cisplatin and observed higher expression of FSP1 and lipid-metabolism-related targets in vitro. The shFSP1 blockade attenuated HNSCC-DTP cell stemness and downregulated tumor invasion and the metastatic rate. We found that cisplatin induced FSP1/ACSL4 axis expression in HNSC-DTPC cells. Finally, we evaluated the HNSCC CSC-inhibitory functions of iFSP1 (a metabolic drug and ferroptosis inducer) used for neo-adjuvant chemotherapy; this was achieved by inducing ferroptosis in a patient-derived xenograft mouse model.

CONCLUSIONS

The present findings elucidate the link between iron homeostasis, ferroptosis, and cancer metabolism in HNSCC-DTP generation and acquisition of chemoresistance. The findings may serve as a suitable model for cancer treatment testing and prediction of precision treatment outcomes. In conclusion, this study provides clinically oriented platforms for evaluating metabolism-modulating drugs (FSP1 inhibitors) and new drug candidates of drug resistance and ferroptotic biomarkers.

Targeted therapy for non-small-cell lung cancer: New insights into regulated cell death combined with immunotherapy

Non-small-cell lung cancer (NSCLC), which has a high rate of metastatic spread and drug resistance, is the most common subtype of lung cancer. Therefore, NSCLC patients have a very poor prognosis and a very low chance of survival. Human cancers are closely linked to regulated cell death (RCD), such as apoptosis, autophagy, ferroptosis, pyroptosis, and necroptosis. Currently, small-molecule compounds targeting various types of RCD have shown potential as anticancer treatments. Moreover, RCD appears to be a specific part of the antitumor immune response; hence, the combination of RCD and immunotherapy might increase the inhibitory effect of therapy on tumor growth. In this review, we summarize small-molecule compounds used for the treatment of NSCLC by focusing on RCD and pharmacological systems. In addition, we describe the current research status of an immunotherapy combined with an RCD-based regimen for NSCLC, providing new ideas for targeting RCD pathways in combination with immunotherapy for patients with NSCLC in the future.

Gigantol exerts anti-lung cancer activity by inducing ferroptosis via SLC7A11-GPX4 axis

Gigantol, a naturally occurring dibenzyl compound derived from various orchid species within the Dendrobium genus, exhibits notable pharmacological activity. We found that gigantol has significant anti-lung cancer properties, both in vitro and in vivo, which it exerts through the induction of ferroptosis. Furthermore, we found gigantol's specific interaction with the subunit solute carrier family 7 member 11 (SLC7A11) within the cystine/glutamate antiporter system (system Xc-), leading to the inhibition of glutathione (GSH) synthesis. This, in turn, disrupts redox homeostasis. Additionally, gigantol hinders the uptake of extracellular cystine via lung cancer cells, resulting in reduced cellular levels of cysteine, a vital precursor in GSH synthesis. This reduction, in turn, leads to an increase in the levels of glutamate. Simultaneously, our study reveals that the decrease in GSH significantly inhibits the activity of glutathione peroxidase 4 (GPX4), a key enzyme within the antioxidant system. Remarkably, N-acetylcysteine, a cystine precursor, effectively reverses gigantol-induced ferroptosis in lung cancer cells. This provides further confirmation that the anti-lung cancer mechanism of gigantol is to induce ferroptosis of lung cancer cells by targeting the SLC7A11-GPX4 signaling axis. In conclusion, our study underscores gigantol's potential as a promising candidate drug for the treatment of patients with lung cancer in clinical practice.

Circular RNA in Non-small Cell Lung Carcinoma: Identification of Targets and New Treatment Modalities

Despite availability of several treatment options for non-small cell lung cancer (NSCLC), such as surgery, chemotherapy, radiation, targeted therapy and immunotherapy, the survival rate of patients for five years is in the range of 22%. Therefore, identification of new targets and treatment modalities for this disease is an important issue. In this context, we screened the PubMed database for up-regulated circular RNAs (circRNAs) which promote growth of NSCLC in preclinical models in vitro as well as in vivo xenograft models in immuno-compromised mice. This approach led to potential targets for further validation and inhibition with small molecules or antibody-derived entities. In case of preclinical validation, the corresponding circRNAs can be inhibited with small interfering RNAs (siRNA) or short hairpin RNAs (shRNA). The identified circRNAs act by sponging microRNAs (miRs) preventing cleavage of the mRNA of the corresponding targets. We identified nine circRNAs up-regulating transmembrane receptors, five circRNAs increasing expression of secreted proteins, nine circRNAs promoting expression of components of signaling pathways, six circRNAs involved in regulation of splicing and RNA processing, six circRNAs up-regulating actin-related and RNA processing components, seven circRNAs increasing the steady-state levels of transcription factors, two circRNAs increasing high-mobility group proteins, four circRNAs increasing components of the epigenetic modification system and three circRNAs up-regulating protein components of additional systems.

Identification of a disulfidptosis-related genes signature for prognostic implication in lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is the most prevalent subtype of non-small cell lung cancer. Additionally, disulfidptosis, a newly discovered type of cell death, has been found to be closely associated with the onset and progression of tumors.

METHODS

The study first identified genes related to disulfidptosis through correlation analysis. These genes were then screened using univariate cox regression and LASSO regression, and a prognostic model was constructed through multivariate cox regression. A nomogram was also created to predict the prognosis of LUAD. The model was validated in three independent data sets: GSE72094, GSE31210, and GSE37745. Next, patients were grouped based on their median risk score, and differentially expressed genes between the two groups were analyzed. Enrichment analysis, immune infiltration analysis, and drug sensitivity evaluation were also conducted.

RESULTS

In this study, we examined 21 genes related to disulfidptosis and developed a gene signature that was found to be associated with a poorer prognosis in LUAD. Our model was validated using three independent datasets and showed AUC values greater than 0.5 at 1, 3, and 5 years. Enrichment analysis revealed that the disulfidptosis-related genes signature had a multifaceted impact on LUAD, particularly in relation to tumor development, proliferation, and metastasis. Patients in the high-risk group exhibited higher tumor purity and lower stromal score, ESTIMATE score, and Immune score.

CONCLUSION

This study constructed a gene signature related to disulfidptosis in lung adenocarcinoma and analyzed its impact on the disease and its association with the tumor microenvironment. The findings of this research provide valuable insights into the understanding of lung adenocarcinoma and could potentially lead to the development of new treatment strategies.

The intricate relationship between autoimmunity disease and neutrophils death patterns: a love-hate story

Autoimmune diseases are pathological conditions that result from the misidentification of self-antigens in immune system, leading to host tissue damage and destruction. These diseases can affect different organs and systems, including the blood, joints, skin, and muscles. Despite the significant progress made in comprehending the underlying pathogenesis, the complete mechanism of autoimmune disease is still not entirely understood. In autoimmune diseases, the innate immunocytes are not functioning properly: they are either abnormally activated or physically disabled. As a vital member of innate immunocyte, neutrophils and their modes of death are influenced by the microenvironment of different autoimmune diseases due to their short lifespan and diverse death modes. Related to neutrophil death pathways, apoptosis is the most frequent cell death form of neutrophil non-lytic morphology, delayed or aberrant apoptosis may contribute to the development anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV). In addition, NETosis, necroptosis and pyroptosis which are parts of lytic morphology exacerbate disease progression through various mechanisms in autoimmune diseases. This review aims to summarize recent advancements in understanding neutrophil death modes in various autoimmune diseases and provide insights into the development of novel therapeutic approaches for autoimmune diseases.

Bulk RNA-seq and scRNA-seq reveal SLC7A11, a key regulatory molecule of ferroptosis, is a prognostic-related biomarker and highly related to the immune system in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common pathological subtype of lung cancer. Ferroptosis is an iron-dependent, non-apoptotic cell death mode, highly correlated with the tumorigenesis and progression of multiple cancers. Solute carrier family 7 member 11 (SLC7A11) maintains the anti-porter activity of cysteine and glutamate to regulate ferroptosis. We collected bulk RNA-seq and scRNA-seq from The Cancer Genome Altas and Gene Expression Omnibus databases. Then, we extracted the expression level of SLC7A11 to perform the differential expression analysis between normal tissues and LUAD tissues. Then, we applied survival, univariate, and multivariate Cox regression analyses to investigate the predictive value of SLC7A11 in LUAD. Gene set enrichment analysis was used to explore the underlying molecular mechanisms of SLC7A11 in LUAD. Finally, we analyzed the relationship of SLC7A11 to the immune status and the curative effect of immunotherapy. The expression level of SLC7A11 in LUAD tissues was markedly increased. The survival analysis, univariate and multivariate Cox regression analysis showed that SLC7A11 was a negative factor for the prognosis of LUAD patients. Gene set enrichment analysis revealed that several immune-related pathways were enriched in the low-level group. The lower SLC7A11 level has a better therapeutic effect of immunotherapy and less probability of immune escape and dysfunction. SLC7A11 was a prognostic-related biomarker and closely correlated with the immune status and therapeutic effect of immunotherapy in LUAD, which could be an effective biomarker for evaluating the prognosis and the therapeutic efficacy of immunotherapy.

Ginsenoside Rh3 induces pyroptosis and ferroptosis through the Stat3/p53/NRF2 axis in colorectal cancer cells

Ginsenoside Rh3 (GRh3) is a seminatural product obtained by chemical processing after isolation from Chinese herbal medicine that has strong antitumor activity against human tumors. However, its antitumor role remains to be elucidated. The aim of this study is to explore the mechanisms underlying the tumor suppressive activity of GRh3 from the perspective of pyroptosis and ferroptosis. GRh3 eliminates colorectal cancer (CRC) cells by activating gasdermin D (GSDMD)-dependent pyroptosis and suppressing solute carrier family 7 member 11 (SLC7A11), resulting in ferroptosis activation through the Stat3/p53/NRF2 axis. GRh3 suppresses nuclear factor erythroid 2-related factor 2 (NRF2) entry into the nucleus, leading to the decrease of heme oxygenase 1 (HO-1) expression, which in turn promotes NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and caspase-1 expression. Finally, caspase-1 activates GSDMD-dependent pyroptosis. Furthermore, GRh3 prevents NRF2 from entering the nucleus, which suppresses SLC7A11, causing the depletion of glutathione (GSH) and accumulation of iron, lipid reactive oxygen species (ROS) and malondialdehyde (MDA), and eventually leading to ferroptosis in CRC cells. In addition, GRh3 effectively inhibits the proliferation of CRC cells in vitro and in nude mouse models. Collectively, GRh3 triggers pyroptotic cell death and ferroptotic cell death in CRC cells via the Stat3/p53/NRF2 axis with minimal harm to normal cells, showing great anticancer potential.

Synergistic disruption of BTK and BCL-2 causes apoptosis while inducing ferroptosis in double-hit lymphoma

Double-hit lymphoma (DHL) is an aggressive subset of Diffuse Large B-cell Lymphoma (DLBCL) with poor outcomes and without satisfying treatment options. BTK inhibitor monotherapy is ineffective to suppress aggressive lymphoma. Hence, combination with other potential agents is warranted. Here, we demonstrated the second generation of BTK inhibitor, zanubrutinib, and a BCL-2 inhibitor, navitoclax, worked in synergistic manner to suppress DHL. Comprehensive in silico approach by interrogating single-cell to bulk-level profiling was employed along with in vitro and in vivo validation in DHL cell lines. Ablation of BTK enhanced sensitivity to navitoclax and suppressed proliferation of DHL cells. Combination of second generation of BTK inhibitor with navitoclax synergistically suppressed DLBCL cells with higher synergy score in DHL subset. The drug combination triggered apoptosis and ferroptosis, with the latter being characterized by reactive oxygen species (ROS) accumulation, extensive lipid peroxidation, and depletion of reduced glutathione. Moreover, ablation of BTK sensitized DHL cells to ferroptosis. Mechanistically, disruption of BTK and BCL-2 triggered ferroptosis by downregulating NRF2 and HMOX1, while deactivating GPX4. Combination of zanubrutinib and navitoclax effectively suppressed tumor growth in vivo. Our data suggest that zanubrutinib and navitoclax synergistically suppressed DHL by inducing apoptosis and ferroptosis.

Ultrasonically Enhanced ZD2767P–Carboxypeptidase G2 Deactivates Cisplatin-Resistant Human Lung Cancer Cells

The prodrug–enzyme regimen ZD2767P+CPG2 is limited by low efficacy. Here, ultrasound was used to modulate ZD2767P+CPG2 (i.e., ZD2767P+CPG2+US) against cisplatin-resistant human lung cancer cells. A549 and A549/DDP (resistant subline) cells received ZD2767P+CPG2 or ZD2767P+CPG2+US. Either ZD2767P+CPG2 or ZD2767P+CPG2+US led to cell death and apoptosis, and ZD2767P+CPG2+US produced stronger effects; comet assays revealed that these two means directly caused DNA double-strand break. Z-VAD-fmk and/or ferrostatin-1 increased the cell survival percentage, and Z-VAD-fmk decreased the apoptosis percentage. The level of transferrin was increased in treated cells, but those of ferroportin and glutathione peroxidase 4 (GPX4) were reduced, with higher intracellular levels of reactive oxygen species and of iron. Intracellular pharmacokinetics of ZD2767D (activated drug) indicated that the peak level, area under the drug level vs. time curve, and mean residence time in ZD2767P+CPG2+US were higher than those in ZD2767P+CPG2. Both ZD2767P+CPG2 and ZD2767P+CPG2+US were effective on xenograft tumors in nude mice; inhibitory rates were 39.7% and 63.5% in A549 tumors and 50.0% and 70.1% in A549/DDP tumors, respectively. A higher apoptosis level and a lower GPX4 level were noted in tumors receiving treatments. No severe adverse events were observed. These data demonstrated that ZD2767P+CPG2+US deactivated cancer cells via apoptosis and ferroptosis pathways, being a candidate therapy for cisplatin-resistant lung cancer.

Ferroptosis and Its Potential Role in Glioma: From Molecular Mechanisms to Therapeutic Opportunities

Glioma is the most common intracranial malignant tumor, and the current main standard treatment option is a combination of tumor surgical resection, chemotherapy and radiotherapy. Due to the terribly poor five-year survival rate of patients with gliomas and the high recurrence rate of gliomas, some new and efficient therapeutic strategies are expected. Recently, ferroptosis, as a new form of cell death, has played a significant role in the treatment of gliomas. Specifically, studies have revealed key processes of ferroptosis, including iron overload in cells, occurrence of lipid peroxidation, inactivation of cysteine/glutathione antiporter system Xc- (xCT) and glutathione peroxidase 4 (GPX4). In the present review, we summarized the molecular mechanisms of ferroptosis and introduced the application and challenges of ferroptosis in the development and treatment of gliomas. Moreover, we highlighted the therapeutic opportunities of manipulating ferroptosis to improve glioma treatments, which may improve the clinical outcome.

Clinical and Biological Significances of a Ferroptosis-Related Gene Signature in Lung Cancer Based on Deep Learning

Acyl-CoA synthetase long-chain family member 4 (ACSL4) has been linked to the occurrence of tumors and is implicated in the ferroptosis process. Deep learning has been applied to many areas in health care, including imaging diagnosis, digital pathology, classification of cancer, and prediction of metastasis. Nonetheless, neither the level of ACSL4 expression nor its predictive significance in non-small-cell lung cancer (NSCLC) is well understood at this time. Predictions of the ACSL4 mRNA expressions in NSCLC and its link to NSCLC prognosis were made with the aid of the Oncomine and TCGA databases. By performing real-time PCR, we detected the levels of ACSL4 expression that were present in human NSCLC samples. Analyses of the diagnostic, as well as the prognostic significance of ACSL4 in NSCLC, were performed with the use of Kaplan-Meier curves. To assess the influence of ACSL4 on ferroptosis in NSCLC cell lines, an inducer of ferroptosis, namely, erastin, was utilized in this study. In NSCLC tissues, there was a substantial decrease in the level of ACSL4 expression (p < 0.001), and this was in line with the findings of the inquiry into the Oncomine and TCGA databases. After that, the findings of the immunohistochemistry analysis revealed that the ACSL4 staining was weakened in NSCLC samples in contrast with the normal samples. It was shown that the differential expression of ACSL4 was substantially linked to the stages of cancer, smoking behaviors, and the status of nodal metastases (all p < 0.001). According to the findings of the survival analysis, both RFS and OS were favorable among NSCLC patients who had elevated expression of ACSL4. The ferroptosis sensitization in cancer cells may be reestablished with upregulation of ACSL4 through gene transfection. Mechanistically, protein ubiquitination could perform a remarkable function in ACSL4-induced ferroptosis. ACSL4, which has a function in ferroptosis as both a contributor and monitor, was shown to be downregulated in NSCLC. This finding suggests that ACSL4 might function as a helpful diagnostic and prognostic biological marker and might also be considered a novel possible treatment target for NSCLC.

Development and validation of a combined ferroptosis- and pyroptosis-related gene signatures for the prediction of clinical outcomes in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is a very heterogeneous cancer with a bad prognosis. Pyroptosis and ferroptosis are two newly discovered forms of regulated cell death, which can trigger inflammation-related immunosuppression in tumor microenvironments, thereby promoting tumor growth. So far, there has been no thorough systematic investigation of the predictive values of ferroptosis and pyroptosis-related genes in LUAD. Therefore, in this study, we conducted a combined analyses in the gene expression of ferroptosis and pyroptosis and identified four distinct subgroups: immobility, ferroptosis, pyroptosis, and mixed. The gene sets most closely associated to both ferroptosis and pyroptosis were utilized to build a risk prediction model based on their variations in survival and biological activities. More importantly, our conclusions from bioinformatics analyses were validated by external experiments in patients with LUAD. In conclusion, the establishment of LUAD subgroups based on the ferroptosis- and pyroptosis-related gene expression profile provided new insights into understanding the roles of programmed cell death in oncogenesis and might contribute to the development of individualized therapy.

Unraveling the interplay between iron homeostasis, ferroptosis and extramedullary hematopoiesis

Iron participates in myriad processes necessary to sustain life. During the past decades, great efforts have been made to understand iron regulation and function in health and disease. Indeed, iron is associated with both physiological (e.g., immune cell biology and function and hematopoiesis) and pathological (e.g., inflammatory and infectious diseases, ferroptosis and ferritinophagy) processes, yet few studies have addressed the potential functional link between iron, the aforementioned processes and extramedullary hematopoiesis, despite the obvious benefits that this could bring to clinical practice. Further investigation in this direction will shape the future development of individualized treatments for iron-linked diseases and chronic inflammatory disorders, including extramedullary hematopoiesis, metabolic syndrome, cardiovascular diseases and cancer.

Iron overload-induced ferroptosis of osteoblasts inhibits osteogenesis and promotes osteoporosis: An in vitro and in vivo study

Growing evidence indicates that iron overload is an independent risk factor for osteoporosis. However, the mechanisms are not fully understood. The purpose of our study was to determine whether iron overload could lead to ferroptosis in osteoblasts and to explore whether ferroptosis of osteoblasts is involved in iron overload-induced osteoporosis in vitro and in vivo. Ferric ammonium citrate was used to mimic iron overload conditions, while deferoxamine and ferrostatin-1 were used to inhibit ferroptosis of MC3T3-E1 cells in vitro. The ferroptosis, osteogenic differentiation and mineralization of MC3T3-E1 cells were assessed in vitro. A mouse iron overload model was established using iron dextran. Immunohistochemical analysis was performed to determine ferroptosis of osteoblasts in vivo. Enzyme-linked immunosorbent assays and calcein-alizarin red S labelling were used to assess new bone formation. Dual x-ray absorptiometry, micro-computed tomography and histopathological analysis were conducted to evaluate osteoporosis. The results showed that iron overload reduced cell viability, superoxide dismutase and glutathione levels, increased reactive oxygen species generation, lipid peroxidation, malondialdehyde levels and ferroptosis-related protein expression, and induced ultrastructural changes in mitochondria. Iron overload could also inhibit osteogenic differentiation and mineralization in vitro. Inhibiting ferroptosis reversed the changes described above. Iron overload inhibited osteogenesis, promoted the ferroptosis of osteoblasts and induced osteoporosis in vivo, which could also be improved by deferoxamine and ferrostatin-1. These results demonstrate that ferroptosis of osteoblasts plays a crucial role in iron overload-induced osteoporosis. Maintaining iron homeostasis and targeting ferroptosis of osteoblasts might be potential measures of treating or preventing iron overload-induced osteoporosis.

Ginsenoside Rh4 Inhibits Colorectal Cancer Cell Proliferation by Inducing Ferroptosis via Autophagy Activation

Colorectal cancer (CRC) is a severe threat to human health. Ginsenosides such as ginsenoside Rh4 have been widely studied in the antitumor field. Here, we investigated the antiproliferative activity and mechanism of Rh4 against CRC in vivo and in vitro. The CRC xenograft model showed that Rh4 inhibited xenograft tumor growth with few side effects (p < 0.05). As determined by MTT colorimetric assays, Western blotting, and immunohistochemical analysis, Rh4 effectively inhibited CRC cell proliferation through autophagy and ferroptosis (p < 0.05). Rh4 significantly upregulated autophagy and ferroptosis marker expression in CRC cells and xenograft tumor tissues in the present study (p < 0.05). Interestingly, the ferroptosis inhibitor ferrostatin-1 (Fer-1) reversed Rh4-induced ferroptosis (p < 0.05). Moreover, the autophagy inhibitor 3-methyladenine (3-MA) also reversed Rh4-induced ferroptosis (p < 0.05). These results indicate that Rh4-induced ferroptosis is regulated via the autophagy pathway. In addition, Rh4 increased reactive oxygen species (ROS) accumulation, leading to the activation of the ROS/p53 signaling pathway (p < 0.05). Transcriptome sequencing also confirmed this (p < 0.05). Moreover, the ROS scavenger N-acetyl-cysteine (NAC) reversed the inhibitory effect of Rh4 on CRC cells (p < 0.05). Therefore, this study proves that Rh4 inhibits cancer cell proliferation by activating the ROS/p53 signaling pathway and activating autophagy to induce ferroptosis, which provides necessary scientific evidence of the great anticancer potential of Rh4.