Non-apoptotic Regulated Cell Death Research Articles

Cell-in-Cell–Mediated Entosis Reveals a Progressive Mechanism in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a deadly malignancy with high intratumoral heterogeneity. There is a lack of effective therapeutics for PDAC. Entosis, a form of nonapoptotic regulated cell death mediated by cell-in-cell structures (CICs), has been reported in multiple cancers. However, the role of entosis in PDAC progression remains unclear. CICs were evaluated using immunohistochemistry and immunofluorescence staining. The formation of CICs was induced by suspension culture. Through fluorescence-activated cell sorting and single-cell RNA sequencing, entosis-forming cells were collected and their differential gene expression was analyzed. Cell functional assays and mouse models were used to investigate malignant phenotypes. Clinical correlations between entosis and PDAC were established by retrospective analysis. Entosis was associated with an unfavorable prognosis for patients with PDAC and was more prevalent in liver metastases than in primary tumors. The single-cell RNA sequencing results revealed that several oncogenes were up-regulated in entosis-forming cells compared with parental cells. These highly entotic cells demonstrated higher oncogenic characteristics invitro and invivo. NET1, neuroepithelial cell transforming gene 1, is an entosis-related gene that plays a pivotal role in PDAC progression and is correlated with poor outcomes. Entosis is correlated with PDAC progression, especially in liver metastasis. NET1 is a newly validated entosis-related gene and a molecular marker of poor outcomes. PDAC cells generate a highly aggressive subpopulation marked by up-regulated NET1 via entosis, which may drive PDAC progression.

The amide derivative of anticopalic acid induces non-apoptotic cell death in triple-negative breast cancer cells by inhibiting FAK activation

Anticopalic acid (ACP), a labdane type diterpenoid obtained from Kaempferia elegans rhizomes, together with 21 semi-synthetic derivatives, were evaluated for their cancer cytotoxic activity. Most derivatives displayed higher cytotoxic activity than the parent compound ACP in a panel of nine cancer cell lines. Among the tested compounds, the amide 4p showed the highest cytotoxic activity toward leukemia cell lines, HL-60 and MOLT-3, with IC50 values of 6.81 ± 1.99 and 3.72 ± 0.26 µM, respectively. More interestingly, the amide derivative 4l exhibited cytotoxic activity with an IC50 of 13.73 ± 0.04 µM against the MDA-MB-231 triple-negative breast cancer cell line, which is the most aggressive type of breast cancer. Mechanistic studies revealed that 4l induced cell death in MDA-MB-231 cells through non-apoptotic regulated cell death. In addition, western blot analysis showed that compound 4l decreased the phosphorylation of FAK protein in a concentration-dependent manner. Molecular docking simulations elucidated that compound 4l could potentially inhibit FAK activation by binding to a pocket of FAK kinase domain. The data suggested that compound 4l could be a potential FAK inhibitor for treating triple-negative breast cancer and worth being further investigated.

Tiliroside induces ferroptosis to repress the development of triple-negative breast cancer cells

Ferroptosis is a newly found form of non-apoptotic regulated cell death that is essential for the advancement of cancer. Tiliroside (Til), an effective natural flavonoid glycoside of oriental paperbush flower, has been explored as a potential anticancer agent in a few cancer types. However, it is unclear whether and how Til could promote the death of triple-negative breast cancer (TNBC) cells by inducing ferroptosis. Our study determined that Til induced cell death and attenuated cell proliferation in TNBC cells in vitro and in vivo with less toxicity for the first time. Functional assays showed that ferroptosis was the predominant form that contributed to Til-induced cell death of TNBC. Mechanistically, Til induces ferroptosis of TNBC cells via independent PUFA-PLS pathways but is closely involved in the Nrf2/HO-1 pathway. Silencing of HO-1 substantially abrogated the tumor-inhibiting effects of Til. In conclusion, our findings suggest that the natural product Til exerted its antitumor activity on TNBC by promoting ferroptosis, and the HO-1/SLC7A11 pathway plays an indispensable role in Til-induced ferroptotic cell death.

The role of ferroptosis mediated by Bmal1/Nrf2 in nicotine -induce injury of BTB integrity.

Nicotine has shown the toxic effects on male reproductive system, and testicular damage is associated with ferroptosis, which is a non-apoptotic regulated cell death driven by iron-dependent lipid peroxidation. However, the role of nicotine on ferroptosis of testicular cells is largely elusive. In the present study, we showed that nicotine destroyed blood-testis barrier (BTB) by interfering with the circadian rhythm of BTB-related factors (ZO-1, N-Cad, Occludin and CX-43) and induced ferroptosis, as reflected via increased clock-control levels of lipid peroxide and decreased ferritin and GPX4, which involved in the circadian. Inhibition of ferroptosis with Fer-1 alleviated nicotine-induced injury of BTB and impaired sperm in vivo. Mechanically, we uncover that the core molecular clock protein, Bmal1, regulates the expression of Nrf2 via direct E-box binding to its promoter to regulate its activity, and nicotine decreases the transcription of Nrf2 through Bmal1 and inactivates Nrf2 pathway and its downstream antioxidant gene, which leads to the imbalance of redox state and ROS accumulation. Intriguingly, nicotine induced lipid peroxidation and subsequent ferroptosis by Bmal1-mediated Nrf2. In conclusion, our study reveals a clear role for the molecular clock in controlling Nrf2 in testis to mediate the ferroptosis induced by nicotine. These findings provide a potential mechanism to prevent smoking and/or cigarette smoke-induced male reproductive injury.

YAP inhibition by CO promotes ferroptosis via ATF4-dependent REDD1 increase in melanoma

Abstract Ferroptotic cell death is a recently recognized form of non-apoptotic regulated cell death and exerts cytotoxicity in cancer cells. Carbon monoxide (CO) as an endogenous physiological mediator confers therapeutic potential in various cancer, while the therapeutic effects of CO on melanoma and its mechanism remain elusive. In this study, we suggest that CO induces ferroptosis via YAP inhibition and ATF4 activation in melanoma. YAP phosphorylation on serine 127 by CO-releasing molecule 2 (CORM2) caused cytoplasmic retention of YAP in B16F10 mouse melanoma cells, resulting in inhibition of YAP activity for transcription of target genes. Thus, CO-mediated YAP inhibition decreased SLC7A11 expression in melanoma cell lines, leading to ferroptosis. Moreover, CO increased REDD1 expression through PERK-ROS-ATF4 pathway. ATF4-REDD expression increased by CO became vulnerable to ferroptosis in melanoma. Thus, CO-induced YAP inhibition can induce ferroptosis viaATF4-mediated REDD1 increase and inhibition of SLC7A11. Furthermore, CO gas inhalation significantly inhibited B16F10 tumor size in xenograft mouse models resulting from ferroptosis induction via down-regulation of SLC7A11 and up-regulation of REDD1. These results suggest that CO acts as a potent inducer of ferroptosis in melanoma and that CO critically depends on YAP inhibition and ATF4 activation to promote ferroptosis.

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.

Abstract 1373: Cell-in-cell mediated entosis reveals a progression mechanism in pancreatic cancer

Abstract Pancreatic cancer (PC) is a deadly malignancy with high intra-tumoral heterogeneity and lacks effective therapeutics. Entosis is a non-apoptotic regulated cell death mediated by cell-in-cell (CIC) structures. However, the impact of entosis on PC progression needs to be determined. This study analyzes the expression levels and prognostic values of entosis-related regulators in public datasets. It identifies that these regulators are commonly upregulated in PC and associated with worse prognosis. We further find that the entotic CIC structures detected in PC specimens have a possible correlation with PC metastases. We enrich a cell population of PC cells undergoing entotic CIC using fluorescence-activated cell sorting (FACS), and several oncogenes, such as NET1, ALDH3A1, PLAT, GALNT5, and FAM3C, were defined as the marker genes of this population using single-cell RNA sequencing (scRNA-seq) analysis. Functionally, this population demonstrates enhanced cell proliferation, migration, invasion, anoikis resistance, sphere formation in vitro, and tumorigenicity in vivo. Moreover, NET1 (neuroepithelial cell transforming gene 1) overexpression promotes cell proliferation, migration, invasion, anoikis resistance, CIC formation, cell competition in vitro, and tumorigenicity in vivo of PC cells. NTE1 is also associated with unfavorable prognosis for PC patients. These results indicate that entosis may play a vital oncogenic role in PC progression. PC cells generate a highly “progressive” subpopulation marked by NET1 via entotic CIC. NET1 is a newly validated gene related to entosis. Targeting entotic processes may be a potential therapeutic option for PC. Citation Format: Jianlu Song, Rexiati Ruze, Yuan Chen, Ruiyuan Xu, Xinpeng Yin, Chengcheng Wang, Yupei Zhao. Cell-in-cell mediated entosis reveals a progression mechanism in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1373.

Role of Ferroptosis in Regulating the Epithelial-Mesenchymal Transition in Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis is a chronic interstitial lung disease whose pathogenesis involves a complex interaction of cell types and signaling pathways. Lung epithelial cells responding to repeated injury experience persistent inflammation and sustained epithelial-mesenchymal transition (EMT). The persistence of EMT-induced signals generates extracellular matrix accumulation, thereby causing fibrosis. Ferroptosis is a newly characterized iron-dependent non-apoptotic regulated cell death. Increased iron accumulation can increase iron-induced oxidant damage in alveolar epithelial cells. Studies have demonstrated that iron steady states and oxidation steady states play an important role in the iron death regulation of EMT. This review summarizes the role of ferroptosis in regulating EMT in pulmonary fibrosis, aiming to provide a new idea for the prevention and treatment of this disease.

Prognostic Prediction Value and Biological Functions of Non-Apoptotic Regulated Cell Death Genes in Lung Adenocarcinoma

ObjectiveTo explore the potential biological functions and prognostic prediction values of non-apoptotic regulated cell death genes (NARCDs) in lung adenocarcinoma. MethodsTranscriptome data of lung adenocarcinoma were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases. We identified differentially expressed NARCDs between lung adenocarcinoma tissues and normal tissues with R software. NARCDs signature was constructed with univariate Cox regression analysis and the least absolute shrinkage and selection operator Cox regression. The prognostic predictive capacity of NARCDs signature was assessed by Kaplan-Meier survival curve, receiver operating characteristic curve, and univariate and multivariate Cox regression analyses. Functional enrichment of NARCDs signature was analyzed with gene set variation analysis, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes. In addition, differences in tumor mutational burden, tumor microenvironment, tumor immune dysfunction and exclusion score, and chemotherapeutic drug sensitivity were analyzed between the high and low NARCDs score groups. Finally, a protein-protein interaction network of NARCDs and immune-related genes was constructed by STRING and Cytoscape software. ResultsWe identified 34 differentially expressed NARCDs associated with the prognosis, of which 16 genes (ATIC, AURKA, CA9, ITGB4, DDIT4, CDK5R1, CAV1, RRM2, GAPDH, SRXN1, NLRC4, GLS2, ADRB2, CX3CL1, GDF15, and ADRA1A) were selected to construct a NARCDs signature. NARCDs signature was identified as an independent prognostic factor (P < 0.001). Functional analysis showed that there were significant differences in mismatch repair, pS3 signaling pathway, and cell cycle between the high NARCDs score group and low NARCDs score group (all P < 0.05). The NARCDs low score group had lower tumor mutational burden, higher immune score, higher tumor immune dysfunction and exclusion score, and lower drug sensitivity (all P < 0.05). In addition, the 10 hub genes (CXCL5, TLR4JUN, IL6, CCL2, CXCL2, ILA, IFNG, IL33, and GAPDH) in protein-protein interaction network of NARCDs and immune-related genes were all immune-related genes. ConclusionThe NARCDs prognostic signature based on the above 16 genes is an independent prognostic factor, which can effectively predict the clinical prognosis of patients of lung adenocarcinoma and provide help for clinical treatment.

The role of autophagy and ferroptosis in sensorineural hearing loss.

Hearing loss has become a common sensory defect in humans. Because of the limited regenerative ability of mammalian cochlear hair cells (HCs), HC damage (caused by ototoxic drugs, aging, and noise) is the main risk factor of hearing loss. However, how HCs can be protected from these risk factors remains to be investigated. Autophagy is a process by which damaged cytoplasmic components are sequestered into lysosomes for degradation. Ferroptosis is a novel form of non-apoptotic regulated cell death involving intracellular iron overloading and iron-dependent lipid peroxide accumulation. Recent studies have confirmed that autophagy is associated with ferroptosis, and their crosstalk may be the potential therapeutic target for hearing loss. In this review, we provide an overview of the mechanisms of ferroptosis and autophagy as well as their relationship with HC damage, which may provide insights for a new future in the protection of HCs.

Mitochondrial Regulation of Ferroptosis in Acute Myeloid Leukemia

Background: Investigations into targeting apoptosis in acute myeloid leukemia (AML) have resulted in breakthrough therapies utilizing Bcl-2 inhibition by venetoclax; however, acquired resistance poses major clinical challenges. Non-apoptotic regulated cell death (RCD) pathways have recently drawn attention especially in solid tumors, but studies targeting these pathways including ferroptosis in leukemia are limited. While ferroptosis is well-defined by iron- and lipid peroxidation-dependency, accumulating evidence suggests that there are also context-specific mechanisms. Since leukemia cells exhibit increased oxidative stress with particular dependency of cell survival on mitochondria, we hypothesized that AML exhibits a unique vulnerability to ferroptosis involving mitochondria. We here study targeting ferroptosis pathway in AML and its mitochondrial (mito-) regulation to develop mechanism-based combination with mito-targeting agents. Results: We first analyzed DepMap datasets to determine the essentiality of ferroptosis-regulating genes in cancer cell lines. Among major anti-ferroptosis genes, GPX4 exhibits high essentiality prominently in leukemia cells, suggesting its potential as a therapeutic target. AML patient survival data from TCGA revealed that high GPX4 expression is associated with shorter survival, indicating prognostic impact. GPX4 is the most downstream molecule to block ferroptosis by reducing lipid hydroperoxide. Although GPX4 is essential for mouse embryonic development, acquired depletion is reported to have no significant effect on hematopoietic stem cells, suggesting tolerability of GPX4-targeted therapies for normal hematopoiesis. We demonstrate that GPX4 inhibition with doxycycline-inducible shRNA or the specific inhibitor ML210 induces ferroptosis in leukemia cells, evidenced by iron-dependent lipid peroxidation and blockade of cell death by the iron chelator deferoxamine. Of note, the classical ferroptosis inducers (xCT inhibitors) sulfasalazine and sorafenib did not induce ferroptosis in AML cells, suggesting a specific relevance of GPX4 in AML ferroptosis. Consistent with solid tumor cells, AML cells show early (6h post-treatment) morphological alterations in mitochondria characterized by shrinkage and increased membrane density upon GPX4 inhibition (Figure 1). Importantly, and in contrast to most solid tumor studies, mitochondria-targeted antioxidants MitoQ and MitoTEMPO completely blocked ferroptosis, suggesting that AML ferroptosis is regulated predominantly by mitochondrial rather than cytoplasmic redox metabolism. To further determine the role of mitochondria in ferroptosis, we utilized HL60 rho0 cells that exhibit abrogated mito-respiration due to lack of mito-DNA. Surprisingly, HL60 rho0 cells were nearly 10 times more sensitive to ML210 than HL60 parental cells, in clear contrast to sarcoma studies demonstrating similar or lower sensitivity to ferroptosis of mito-DNA deficient cells. Consistently, degradation of the respiratory complex with hyperactivation of mito-protease ClpP by imipridone ONC212 sensitized cells to GPX4 inhibition in HL60 parental cells but not in rho0 cells, further supporting the role of mito-respiration in the protection of cells against ferroptosis. As venetoclax (Ven) is one of the most widely used mitochondria-targeting agents in AML that also inhibits mito-respiration, we tested the combination of GPX4 inhibitor ML210 and Ven. This combinatorial treatment exerts synergistic anti-leukemia effects in AML cell lines and primary cells from AML patients including those with Ven resistance (Figure 2). Unexpectedly, and as a novel mechanism of GPX4 inhibition-mediated ferroptosis, we found that ML210 induces BAX/BAK-independent cytochrome C release from mitochondria, which is blocked by MitoQ. Combination with Ven further enhanced cytochrome C release, as one of potential mechanisms of the observed synergistic cell death. Conclusion: Our data suggest therapeutic potential of ferroptosis induction in AML by targeting GPX4 with the mechanistic involvement of mito-respiration. The combination of GPX4 and BCL-2 inhibition is synergistic and capable of overcoming Ven resistance. Studies are in progress to elucidate the molecular link between mito-respiration/redox and cytochrome C release and to investigate ferroptosis induction in vivo. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Nanoparticle-induced Ferroptosis for Cancer Therapy

Ferroptosis is a recently identified form of non-apoptotic regulated cell death (RCD). It is primarily characterized by the accumulation of lipid peroxide, which is iron-dependent. Ferroptosis is essential for the treatment of tumors, renal failure, and ischemia reperfusion exposure (IRI). Ferroptosis and nanomedicine are now the subjects of intense study and clinical attention. There is, however, a limited amount of data on the precise molecular pathways behind ferroptosis and the contribution of nanoparticles. This work provides a thorough overview of ferroptosis, its regulations, and the various mechanisms by which iron- and non-iron-based nanoparticles potentially trigger ferroptosis in the context of cancer therapy. We investigated the most recent developments in ferroptosis research and nanoparticles as ferrotosis-inducing agents by performing extensive literature studies based on the notion of ferroptosis and cancer therapy and a thorough examination of various publications regarding nanoparticles. Our results suggest that tumor suppression and treatment efficacy can both be enhanced by ferroptosis triggered via nanoparticles. New ideas and viewpoints have also been put out for the treatment of ferroptosis-induced cancer, which will make a significant contribution to cancer therapy.

Identification of cuprotosis-mediated subtypes, the development of a prognosis model, and influence immune microenvironment in hepatocellular carcinoma.

PurposeCuprotosis is a newly discovered form of non-apoptotic regulated cell death and is characterized by copper-dependent and associated with mitochondrial respiration. However, the prognostic significance and function of cuprotosis-related genes (CRGs) in hepatocellular carcinoma (HCC) are unknown. This study aims to develop cuprotosis-mediated patterns-related gene (CMPRG) prediction models for the prognosis of patients with HCC, exploring the functional underlying the CRGs on the influence of tumor microenvironment (TME) features.Experimental designThis study obtained transcriptome profiling and the corresponding clinical information from the TCGA and GEO databases. Besides, the Cox regression model with LASSO was implemented to build a multi-gene signature, which was then validated in an internal validation set and two external validation sets through Kaplan-Meier, DCA, and ROC analyses.ResultsAccording to the LASSO analysis, we screened out a cuprotosis-mediated pattern 5-gene combination (including PBK; MMP1; GNAZ; GPC1 and AKR1D1). A nomogram was constructed for the presentation of the final model. The ROC curve assessed the model’s predictive ability, which resulted in an area under the curve (AUC) values ranging from 0.604 to 0.787 underwent internal and two external validation sets. Meanwhile, the risk score divided the patients into two groups of high and low risk, and the survival rate of high-risk patients was significantly lower than that of low-risk patients (P<0.01). The risk score could be an independent prognostic factor in the multifactorial Cox regression analysis (P<0.01). Functional analysis revealed that immune status, mutational loads, and drug sensitivity differed between the two risk groups.ConclusionsIn summary, we identified three cuprotosis-mediated patterns in HCC. And CMPRGs are a promising candidate biomarker for HCC early detection, owing to their strong performance in predicting HCC prognosis and therapy. Quantifying cuprotosis-mediated patterns in individual samples may help improve the understanding of multiomic characteristics and guide the development of targeted therapy for HCC.

Methylation Drives SLC2A1 Transcription and Ferroptosis Process Decreasing Autophagy Pressure in Colon Cancer.

Colon cancer is a common malignant tumor in the digestive tract, with relatively high rates of morbidity and mortality. It is the third most common type of tumor in the world. The effective treatment of advanced colon cancer is limited, so it is particularly important to study the new pathogenesis of colon cancer. Ferroptosis is a nonapoptotic regulated cell death mode driven by iron-dependent lipid peroxidation, a process which has been discovered in recent years. Autophagy involves lysosomal degradation pathways that promote or prevent cell death. High levels of autophagy are associated with ferroptosis, but a clear association has not yet been made between ferroptosis and autophagy in colon cancer. Through the analysis of transcriptome expression profiling data in colon cancer, we obtained the common upregulated genes and downregulated genes by recording the intersection of the differentially expressed genes in each dataset. Solute Carrier Family 2 Member 1 (SLC2A1) was identified by combining autophagy genes obtained from GeneCards and ferroptosis genes obtained from FerrDb. In order to explore the clinical significance and prognostic value of SLC2A1, we utilized massive databases to conduct an in-depth exploration of the methylation of SLC2A1, and we also investigated the differences in immune infiltration between tumor and normal tissues. We found that there are abundant methylation sites in SLC2A1 and that the methylation of SLC2A1 is correlated with the immunosuppression of tumor tissue. We discovered that during the induction of environmental factors, the transcription and methylation levels of SLC2A1 were greatly increased, autophagy and ferroptosis were inhibited, and the immune system was defective, resulting in a poor prognosis for patients. These results suggest that the autophagy and ferroptosis-related gene SLC2A1 is involved in the tumor immune regulation of colon cancer, and SLC2A1 may become a new therapeutic target for colon cancer.

Orchestrated Action of AMPK Activation and Combined VEGF/PD-1 Blockade with Lipid Metabolic Tunning as Multi-Target Therapeutics against Ovarian Cancers.

Ovarian cancer is one of the most lethal gynecological malignancies worldwide, and chemoresistance is a critical obstacle in the clinical management of the disease. Recent studies have suggested that exploiting cancer cell metabolism by applying AMP-activated protein kinase (AMPK)-activating agents and distinctive adjuvant targeted therapies can be a plausible alternative approach in cancer treatment. Therefore, the perspectives about the combination of AMPK activators together with VEGF/PD-1 blockade as a dual-targeted therapy against ovarian cancer were discussed herein. Additionally, ferroptosis, a non-apoptotic regulated cell death triggered by the availability of redox-active iron, have been proposed to be governed by multiple layers of metabolic signalings and can be synergized with immunotherapies. To this end, ferroptosis initiating therapies (FITs) and metabolic rewiring and immunotherapeutic approaches may have substantial clinical potential in combating ovarian cancer development and progression. It is hoped that the viewpoints deliberated in this review would accelerate the translation of remedial concepts into clinical trials and improve the effectiveness of ovarian cancer treatment.

Role of ferroptosis in gastrointestinal tumors: From mechanisms to therapies.

Ferroptosis is an iron-dependent nonapoptotic regulated cell death, which is mainly caused by an abnormal increase in lipid oxygen free radicals and an imbalance in redox homeostasis. Recently, ferroptosis has been shown to have implications in various gastrointestinal cancers, such as gastric carcinoma, hepatocellular carcinoma, and pancreatic cancer. This review summarises the latest research on ferroptosis, its mechanism of action, and its role in the progression of different gastrointestinal tumors to provide more information regarding the prevention and treatment of these tumors.

Regulated cell death joins in atherosclerotic plaque silent progression

Non-apoptotic regulated cell death (ferroptosis and necroptosis) leads to the release of damage-associated molecular patterns (DAMPs), which initiate and perpetuate a non-infectious inflammatory response. We hypothesize that DAMPs and non-apoptotic regulated cell death are critical players of atherosclerotic plaque progression with inadequate response to lipid-lowering treatment. We aimed to uncover the silent mechanisms that govern the existing residual risk of cardiovascular-related mortality in experimental atherosclerosis. Proteomic and genomic approaches were applied on the ascending aorta of hyperlipidemic rabbits and controls with and without lipid-lowering treatment. The hyperlipidemic animals, which presented numerous heterogeneous atherosclerotic lesions, exhibited high concentrations of serum lipids and increased lipid peroxidation oxidative stress markers. The analyses revealed the significant upregulation of DAMPs and proteins implicated in ferroptosis and necroptosis by hyperlipidemia. Some of them did not respond to lipid-lowering treatment. Dysregulation of five proteins involved in non-apoptotic regulated cell death proteins (VDAC1, VDAC3, FTL, TF and PCBP1) and nine associated DAMPs (HSP90AA1, HSP90AB1, ANXA1, LGALS3, HSP90B1, S100A11, FN, CALR, H3-3A) was not corrected by the treatment. These proteins could play a key role in the atherosclerotic silent evolution and may possess an unexplored therapeutic potential. Mass spectrometry data are available via ProteomeXchange with identifier PXD026379.

Ferroptosis in Cancer Immunotherapy—Implications for Hepatocellular Carcinoma

Ferroptosis is a recently recognized iron-dependent form of non-apoptotic regulated cell death (RCD) characterized by lipid peroxide accumulation to lethal levels. Cancer cells, which show an increased iron dependency to enable rapid growth, seem vulnerable to ferroptosis. There is also increasing evidence that ferroptosis might be immunogenic and therefore could synergize with immunotherapies. Hepatocellular carcinoma (HCC) is the most common primary liver tumor with a low survival rate due to frequent recurrence and limited efficacy of conventional chemotherapies, illustrating the urgent need for novel drug approaches or combinatorial strategies. Immunotherapy is a new treatment approach for advanced HCC patients. In this setting, ferroptosis inducers may have substantial clinical potential. However, there are still many questions to answer before the mystery of ferroptosis is fully unveiled. This review discusses the existing studies and our current understanding regarding the molecular mechanisms of ferroptosis with the goal of enhancing response to immunotherapy of liver cancer. In addition, challenges and opportunities in clinical applications of potential candidates for ferroptosis-driven therapeutic strategies will be summarized. Unraveling the role of ferroptosis in the immune response could benefit the development of promising anti-cancer therapies that overcome drug resistance and prevent tumor metastasis.

Targeting Regulated Cell Death with Pharmacological Small Molecules: An Update on Autophagy-Dependent Cell Death, Ferroptosis, and Necroptosis in Cancer.

Regulated cell death is a widely attractive subject among the topics of cancer therapy and has gained some advances for discovery of targeted anticancer drugs. In the past decade, nonapoptotic regulated cell death has been implicated in the development and therapeutic responses of a variety of human cancers. Hitherto, targeting autophagy-dependent cell death (ADCD), ferroptosis, and necroptosis with small molecules has been emerging as a hopeful strategy for the improvement of potential cancer therapy, which may have an advantage to bypass the apoptosis-resistance machinery. Thus, in this perspective, we concentrate on the key molecular insights into ADCD, ferroptosis, and necroptosis and summarize the corresponding small molecules in potential cancer therapy. Moreover, the relationships between the three subroutines and small molecules modulating the crosstalk are discussed. We believe that these inspiring findings would be advantageous to exploiting more potential targets and pharmacological small molecules in future cancer treatment.

Ferroptosis-Related Long Non-Coding RNA Signature Contributes to the Prediction of Prognosis Outcomes in Head and Neck Squamous Cell Carcinomas.

Background: Head and neck squamous cell carcinoma (HNSCC) is a malignant tumor, which makes the prognosis prediction challenging. Ferroptosis is an iron-dependent form of non-apoptotic regulated cell death, which could affect cancer development. However, the prognostic value of ferroptosis-related long non-coding RNA (lncRNA) in HNSCC is still limited. Methods: In the current study, we employed the DESeq2 method to characterize the differentially expressed ferroptosis-related genes (FEGs) between cancer and normal samples. Next, the FEG-related lncRNAs (FElncRNAs) were identified using Spearman’s correlation analysis and multiple permutation hypotheses. Subsequently, LASSO and stepwise multivariate Cox regression analyses were undertaken to recognize the prognosis-related FElncRNA signature (PFLS) and risk scores. Results: Herein, we first identified 60 dysregulated FEGs and their co-expressed FElncRNAs in HNSCC. Then, we recognized a set of six FElncRNAs PFLS (SLCO4A1-AS1, C1RL-AS1, PCED1B-AS1, HOXB-AS3, MIR9-3HG, and SFTA1P) for predicting patients’ prognostic risks and survival outcomes. We also assessed the efficiency of PFLS in the test set and an external validation cohort. Further parsing of the tumor immune microenvironment showed the PFLS was closely associated with immune cell infiltration abundances. Notably, the low-risk group of the PFLS showed a higher MHC score and cytolytic activity (CYT) score than the high-risk group, implying the low-risk group may have greater tumor surveillance and killing ability. In addition, we observed that the expression levels of two immune checkpoints (ICPs), i.e., programmed cell death protein 1 (PD-1) and programmed cell death 1 ligand 1 (PD-L1), showed significant associations with patients’ risk score, prompting the role of the PFLS in ICP blockade therapy. Finally, we also constructed a drug–PFLS network to reinforce the clinical utilities of the PFLS. Conclusion: In summary, our study indicated that FElncRNAs played an important role in HNSCC survival prediction. Identification of PFLS will contribute to the development of novel anticancer therapeutic strategies.