TIGAR drives colorectal cancer ferroptosis resistance through ROS/AMPK/SCD1 pathway

Targeting Ferroptosis as an Advance Strategy in Cancer Therapy

Ferroptosis, triggered by the buildup of lipid peroxidation and reliance on iron, is crucial in maintaining cellular balance. Research related to ferroptosis has surged due to its distinct characteristics compared to other forms of controlled cell death, both in terms of mechanisms and appearance. Scientists believe that directing efforts towards targeting ferroptosis could pave the way for innovative precision cancer treatments, addressing challenges such as cancer recurrence and resistance. This review systematically outlines the molecular mechanisms behind ferroptosis, the substances that induce ferroptosis, and how different cancers respond to ferroptotic inducers. Also, the study further looks into the molecular basis of ferroptosis in tumor biology. It provides a conceptual framework illustrating its interaction with the tumor immune microenvironment, guiding treatment choices, predicting efficacy, exploring combination therapies, and identifying new therapeutic targets to overcome cancer resistance to standard treatments. Finally, it highlights key issues and obstacles in future research and clinical translation of ferroptosis as a potential strategy in cancer therapy.

Ferroptosis: Biology and Role in Gastrointestinal Disease

Ferroptosis is a form of nonapoptotic cell death that involves iron-dependent phospholipid peroxidation induced by accumulation of reactive oxygen species, and results in plasma membrane damage and the release of damage-associated molecular patterns. Ferroptosis has been implicated in aging and immunity, as well as disease states including intestinal and liver conditions and cancer. To date, several ferroptosis-associated genes and pathways have been implicated in liver disease. Although ferroptotic cell death is associated with dysfunction of the intestinal epithelium, the underlying molecular basis is poorly understood. As the mechanisms regulating ferroptosis become further elucidated, there is clear potential to use ferroptosis to achieve therapeutic benefit.

Bazi Bushen capsule attenuates cardiac systolic injury via SIRT3/SOD2 pathway in high-fat diet-fed ovariectomized mice

Background

Bazi Bushen capsule (BZBS) is a Chinese herbal compound that is clinically used to treat fatigue and forgetfulness. However, it is still unclear whether and how BZBS affects heart function decline in menopausal women. This study aimed to examine the effect of BZBS on cardiac function in a high-fat diet-fed ovariectomy (HFD-fed OVX) mouse model and elucidate the underlying mechanism of this effect.

Methods

The experimental animals were divided into five groups: sham group, HFD-fed OVX group, and BZBS (0.7, 1.4, 2.8 g/kg) intervention groups. Senescence β-galactosidase staining and echocardiography were used to evaluate cardiac function. SwissTargetPrediction, KEGG and GO enrichment analyses were used to screen the underlying mechanism of BZBS. The morphological and functional changes in cardiac mitochondria and the underlying molecular mechanism were assessed by transmission electron microscopy, western blotting and biochemical assays. STRING database was used to analysis protein-protein interaction (PPI) network. Molecular docking studies were employed to predict the interactions of specific BZBS compounds with their protein targets.

Results

BZBS treatment ameliorated cardiac senescence and cardiac systole injury in HFD-fed OVX mice. GO and KEGG analyses revealed that the 530 targets of the 14 main components of BZBS were enriched mainly in the oxidative stress-associated pathway, which was confirmed by the finding that BZBS treatment prevented abnormal morphological changes and oxidative stress damage to cardiac mitochondria in HFD-fed OVX mice. Furthermore, the STRING database showed that the targets of BZBS were broadly related to the Sirtuins family. And BZBS upregulated the SIRT3 and elevated the activity of SOD2 in the hearts of HFD-fed OVX mice, which was also verified in vitro. Additionally, we revealed that imperatorin and osthole from the BZBS upregulated the expression of SIRT3 by directly docking with the transcription factors HDAC1, HDAC2, and BRD4, which regulate the expression of SIRT3.

Conclusion

This research shows that the antioxidative effect and cardioprotective role of BZBS on HFD-fed OVX mice involves an increase in the activity of the SIRT3/SOD2 pathway, and the imperatorin and osthole of BZBS may play central roles in this process.

PPP2CA Inhibition Promotes Ferroptosis Sensitivity Through AMPK/SCD1 Pathway in Colorectal Cancer

PURPOSE

Colorectal cancer (CRC) is a very common malignancy of the digestive system. Despite a variety of treatments including surgery, chemotherapeutic and targeted drugs, the prognosis for patients with CRC is still unsatisfactory and the mortality remains high. Protein phosphorylation plays an essential role in tumorigenesis and progression and is also crucial for protein to act with proper functions. Ferroptosis is found widely involved in various diseases especially tumors as a newly identified programmed cell death.

METHODS

In our study, we aimed at PPP2CA as a prospective target which may play a crucial role in CRC progression. In one hand, knockdown of PPP2CA significantly enhanced the malignant phenotype in HCT116. In the other hand, knockdown of PPP2CA significantly enhanced Erastin-induced ferroptosis as well.

RESULTS

Specifically, knockdown of PPP2CA in HCT116 significantly increased the relative level of malondialdehyde (MDA), reactive oxygen species (ROS) and Fe2+, and decreased GSH/GSSG ratio after the treatment of certain concentration of Erastin. Besides, we found that the inhibition of PPP2CA further led to the suppression of SCD1 expression in CRC cells in a AMPK-dependent way.

CONCLUSION

Ultimately, we conclude that PPP2CA may regulate Erastin-induced ferroptosis through AMPK/SCD1 signaling pathway.

Gemfibrozil-Platinum(IV) Precursors for New Enhanced-Starvation and Chemotherapy In Vitro and In Vivo

A brand-new enhanced starvation is put forward to trigger sensitized chemotherapy: blocking tumor-relation blood vessel formation and accelerating nutrient degradation and efflux. Following this concept, two cisplatin-like gemfibrozil-derived Pt(IV) prodrugs, GP and GPG, are synthesized. GP and GPG had nanomolar IC50 against A2780 cells and higher selectivity against normal cells than cisplatin. Bioactivity results confirmed that GP and GPG highly accumulated in cells and induced DNA damage, G2-phase arrest, and p53 expression. Besides, they could increase ROS and MDA levels and reduce mitochondrial membrane potential and Bcl-2 expression to promote cell apoptosis. In vivo, GP showed superior antitumor activity in A2780 tumor-bearing mice with no observable tissue damage. Mechanistic studies suggested that highly selective chemotherapy could be due to the new enhanced starvation effect: blocking vasculature formation via inhibiting the CYP2C8/EETs pathway and VEGFR2, NF-κB, and COX-2 expression and cholesterol efflux and degradation acceleration via increasing ABCA1 and PPARα.

Mechanism of metal ion-induced cell death in gastrointestinal cancer

Gastrointestinal (GI) cancer is one of the most severe types of cancer, with a significant impact on human health worldwide. Due to the urgent demand for more effective therapeutic strategies against GI cancers, novel research on metal ions for treating GI cancers has attracted increasing attention. Currently, with accumulating research on the relationship between metal ions and cancer therapy, several metal ions have been discovered to induce cell death. In particular, the three novel modes of cell death, including ferroptosis, cuproptosis, and calcicoptosis, have become focal points of research in the field of cancer. Meanwhile, other metal ions have also been found to trigger cell death through various mechanisms. Accordingly, this review focuses on the mechanisms of metal ion-induced cell death in GI cancers, hoping to provide theoretical support for further GI cancer therapies.

PHGDH knockdown increases sensitivity to SR1, an aryl hydrocarbon receptor antagonist, in colorectal cancer by activating the autophagy pathway

Colorectal cancer (CRC) has emerged as the third most prevalent and second deadliest cancer worldwide. Metabolic reprogramming is a key hallmark of cancer cells. Phosphoglycerate dehydrogenase (PHGDH) is over-expressed in multiple cancers, including CRC. Although the role of PHGDH in metabolism has been extensively investigated, its effects on CRC development remains to be elucidated. In the present study, it was demonstrated that PHGDH expression was significantly up-regulated in colorectal cancer. PHGDH expression was positively correlated with that of the aryl hydrocarbon receptor (AhR) and its target genes, CYP1A1 and CYP1B1, in CRC cells. Knockdown of PHGDH reduced AhR levels and activity, as well as the ratio of reduced to oxidized glutathione. The selective AhR antagonist stemregenin 1 induced cell death through reactive oxygen species-dependent autophagy in CRC cells. PHGDH knockdown induced CRC cell sensitivity to stemregenin 1 via the autophagy pathway. Our findings suggest that PHGDH modulates AhR signaling and the redox-dependent autophagy pathway in CRC, and that the combination of inhibition of both PHGDH and AhR may be a novel therapeutic strategy for CRC.

KDM4B down-regulation facilitated breast cancer cell stemness via PHGDH upregulation in H3K36me3-dependent manner

Despite recent advances have been made in clinical treatments of breast cancer, the general prognosis of patients remains poor. Therefore, it is imperative to develop a more effective therapeutic strategy. Lysine demethylase 4B (KDM4B) has been reported to participate in breast cancer development recently, but its exact biological role in breast cancer remains unclear. Here, we observed that KDM4B was down-regulated in human primary BRCA tissues and the low levels of KDM4B expression were correlated with poor survival. Gain- and loss-of-function experiments showed that KDM4B inhibited the proliferation and metastasis of breast cancer cells. Besides, knockdown of KDM4B promoted the epithelial-mesenchymal transition (EMT) and cell stemness in breast cancer cells. Mechanistically, KDM4B down-regulates PHGDH by decreasing the enrichment of H3K36me3 on the promoter region of PHGDH. Knockdown of PHGDH could significantly reversed proliferation, migration, EMT, and cell stemness induced by KDM4B silencing in breast cancer cells. Collectively, we propose a model for a KDM4B/PHGDH axis that provides novel insight into breast cancer development, which may serve as a potential factor for predicting prognosis and a therapeutic target for breast cancer.

In Vitro Ferroptotic and Antitumor Effect of Free or Liposome-Encapsulated Artesunate in Papillary Thyroid Cancer Cells

Papillary thyroid cancer (PTC) is generally treated as an indolent and curable cancer. However, the unavailability of surgery and ineffective radiotherapy persists in PTCs, resulting in poor outcomes and low survival rates. Thus, new chemotherapeutic strategies for PTCs are urgently needed. Resistance to ferroptosis remarkably contributes to cancer occurrence and progression. Artesunate (ART) has been repurposed as an anticancer drug, as it induces cell death in numerous cancers. However, whether ART induces ferroptosis in PTC cells and, consequently, facilitates PTC therapy remains elusive. Furthermore, overcoming the pharmacological limitations of ART is a key requirement to support its clinical application. Herein, we reanalyzed the Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression database (GTEx) to characterize the occurrence of resistance to ferroptosis in thyroid cancer. In vitro results showed that ART induced ferroptosis in PTC cells by increasing the cellular iron content. The encapsulation of ART by liposomes did not alter the efficiency in inducing ferroptosis and inhibiting the invasion and migration of PTC cells compared with direct ART application. Thus, PTC resistance to ferroptosis can be overcome by ART and liposome-encapsulated ART.

Advancing the frontiers of colorectal cancer treatment: harnessing ferroptosis regulation

In recent years, colorectal cancer incidence and mortality have increased significantly due to poor lifestyle choices. Despite the development of various treatments, their effectiveness against advanced/metastatic colorectal cancer remains unsatisfactory due to drug resistance. However, ferroptosis, a novel iron-dependent cell death process induced by lipid peroxidation and elevated reactive oxygen species (ROS) levels along with reduced activity of the glutathione peroxidase 4 (GPX4) antioxidant enzyme system, shows promise as a therapeutic target for colorectal cancer. This review aims to delve into the regulatory mechanisms of ferroptosis in colorectal cancer, providing valuable insights into potential therapeutic approaches. By targeting ferroptosis, new avenues can be explored for innovative therapies to combat colorectal cancer more effectively. In addition, understanding the molecular pathways involved in ferroptosis may help identify biomarkers for prognosis and treatment response, paving the way for personalized medicine approaches. Furthermore, exploring the interplay between ferroptosis and other cellular processes can uncover combination therapies that enhance treatment efficacy. Investigating the tumor microenvironment's role in regulating ferroptosis may offer strategies to sensitize cancer cells to cell death induction, leading to improved outcomes. Overall, ferroptosis presents a promising avenue for advancing the treatment of colorectal cancer and improving patient outcomes.

Reactive oxygen species in colorectal cancer adjuvant therapies

Colorectal cancer (CRC), a prevalent global malignancy, often necessitates adjuvant therapies such as chemotherapy, radiotherapy, targeted therapy, and immunotherapy to mitigate tumor burden in advanced stages. The efficacy of these therapies is significantly influenced by reactive oxygen species (ROS). Previous research underscores the pivotal role of ROS in gut pathology, targeted therapy, and drug resistance. ROS-mediated CRC adjuvant therapies encompass a myriad of mechanisms, including cell death and proliferation, survival and cell cycle, DNA damage, metabolic reprogramming, and angiogenesis. Preliminary clinical trials have begun to unveil the potential of ROS-manipulating therapy in enhancing CRC adjuvant therapies. This review aims to provide a comprehensive synthesis of studies exploring the role of ROS in CRC adjuvant therapies.

Mitochondrial Glutathione in Cellular Redox Homeostasis and Disease Manifestation

Mitochondria are critical for providing energy to maintain cell viability. Oxidative phosphorylation involves the transfer of electrons from energy substrates to oxygen to produce adenosine triphosphate. Mitochondria also regulate cell proliferation, metastasis, and deterioration. The flow of electrons in the mitochondrial respiratory chain generates reactive oxygen species (ROS), which are harmful to cells at high levels. Oxidative stress caused by ROS accumulation has been associated with an increased risk of cancer, and cardiovascular and liver diseases. Glutathione (GSH) is an abundant cellular antioxidant that is primarily synthesized in the cytoplasm and delivered to the mitochondria. Mitochondrial glutathione (mGSH) metabolizes hydrogen peroxide within the mitochondria. A long-term imbalance in the ratio of mitochondrial ROS to mGSH can cause cell dysfunction, apoptosis, necroptosis, and ferroptosis, which may lead to disease. This study aimed to review the physiological functions, anabolism, variations in organ tissue accumulation, and delivery of GSH to the mitochondria and the relationships between mGSH levels, the GSH/GSH disulfide (GSSG) ratio, programmed cell death, and ferroptosis. We also discuss diseases caused by mGSH deficiency and related therapeutics.

A ROS-responsive microsphere capsule encapsulated with NADPH oxidase 4 inhibitor ameliorates macrophage inflammation and ferroptosis

Inflammatory macrophages within the synovium play a pivotal role in the progression of arthritis inflammation. Effective drug therapy targeting inflammatory macrophages has long been a goal for clinicians and researchers. The standard approach for treating osteoarthritis (OA) involves systemic treatment and local injection. However, the high incidence of side effects associated with long-term drug administration increases the risk of complications in patients. Additionally, the rapid clearance of the joint cavity poses a biological barrier to the therapeutic effect. NADPH oxidase 4 (NOX4) is an enzyme protein regulating the cellular redox state by generating reactive oxygen species (ROS) within the cell. In this study, we designed and fabricated a hydrogel microsphere consisting of methyl methacrylate (MMA) and polyvinyl acetate (PVA) as the outer layer structure. We then loaded GLX351322 (GLX), a novel selective NOX4 inhibitor, into hydrogel microspheres through self-assembly with the compound polyethylene glycol ketone mercaptan (mPEG-TK) containing a disulfide bond, forming nanoparticles (mPEG-TK-GLX), thus creating a two-layer drug-loaded microspheres capsule with ROS-responsive and slow-releasing capabilities. Our results demonstrate that mPEG-TK-GLX@PVA-MMA effectively suppressed TBHP-induced inflammation, ROS production, and ferroptosis, indicating a promising curative strategy for OA and other inflammatory diseases in the future.

Novel Insights on Ferroptosis Modulation as Potential Strategy for Cancer Treatment: When Nature Kills

Significance: The multifactorial nature of the mechanisms implicated in cancer development still represents a major issue for the success of established antitumor therapies. The discovery of ferroptosis, a novel form of programmed cell death distinct from apoptosis, along with the identification of the molecular pathways activated during its execution, has led to the uncovering of novel molecules characterized by ferroptosis-inducing properties. Recent advances: As of today, the ferroptosis-inducing properties of compounds derived from natural sources have been investigated and interesting findings have been reported both in vitro and in vivo. Critical Issues: Despite the efforts made so far, only a limited number of synthetic compounds have been identified as ferroptosis inducers, and their utilization is still limited to basic research. In this review, we analyzed the most important biochemical pathways involved in ferroptosis execution, with particular attention to the newest literature findings on canonical and non-canonical hallmarks, together with mechanisms of action of natural compounds identified as novel ferroptosis inducers. Compounds have been classified based on their chemical structure, and modulation of ferroptosis-related biochemical pathways has been reported. Future Directions: The outcomes herein collected represent a fascinating starting point from which to take hints for future drug discovery studies aimed at identifying ferroptosis-inducing natural compounds for anticancer therapies. Antioxid. Redox Signal. 40, 40-85.

Impact of TP53-induced glycolysis and apoptosis regulator on malignant activity and resistance to ferroptosis in intrahepatic cholangiocarcinoma

TP53-induced glycolysis and apoptosis regulator (TIGAR) is an important gene that encodes a regulatory enzyme of glycolysis and reactive oxygen species (ROS) detoxification and is associated with worse prognosis in various cancers. Ferroptosis is a recently identified type of programmed cell death that is triggered by iron-dependent lipid peroxidation. There are no reports on the prognostic impact of TIGAR on intrahepatic cholangiocarcinoma (ICC), and its role in ferroptosis is unclear. Ninety ICC patients who had undergone hepatic resection were enrolled. Immunohistochemical staining for TIGAR was performed. The regulation of malignant activity by TIGAR and the association between ferroptosis and TIGAR were investigated in vitro. Twenty-two (24.4%) patients were categorized into TIGAR-high and -low groups by immunohistochemical staining. There were no noticeable differences in background factors between the two groups, but TIGAR positivity was an independent prognostic factor in disease-free survival (hazard ratio [HR], 2.00; 95% confidence interval [CI], 1.04-3.85, p = 0.0378) and overall survival (HR, 2.10; 95% CI, 1.03-4.30, p = 0.00422) in a multivariate analysis. In vitro, TIGAR knockdown (KD) decreased cell motility (cell proliferation/migration/invasion/colony-forming capabilities) and elevated ROS and lipid peroxidation. This indicated that TIGAR KD induced ferroptosis. TIGAR KD-induced ferroptosis was suppressed using liproxstatin. TIGAR KD decreased the expression of glutathione peroxidase 4, known as factor-suppressing ferroptosis. The combination of TIGAR KD with cisplatin significantly induced more ferroptosis. In conclusion, TIGAR is associated with poor outcomes in ICC patients and resistance to ferroptosis.

The Therapeutic Potential of Targeting Ferroptosis in the Treatment of Mitochondrial Cardiomyopathies and Heart Failure

ABSTRACT

Ferroptosis is a form of iron-regulated cell death implicated in a wide array of diseases, including heart failure, hypertension, and numerous cardiomyopathies. In addition, mitochondrial dysfunction has been associated with several of these same disease states. However, the role of the mitochondrion in ferroptotic cell death remains debated. As a major regulator of cellular iron levels, the mitochondria may very well play a crucial role in the mechanisms behind ferroptosis, but at this point, this has not been adequately defined. Emerging evidence from our laboratory and others indicates a critical role of mitochondrial Sirtuin 3, a deacetylase linked with longevity and protection against numerous conditions, in the prevention of cardiovascular diseases. Here, we provide a brief overview of the potential roles of Sirtuin 3 in mitochondrial iron homeostasis and its contribution to the mitochondrial cardiomyopathy of Friedreich's ataxia and diabetic cardiomyopathy. We also discuss the current knowledge of the involvement of ferroptosis and the mitochondria in these and other cardiovascular disease states, including doxorubicin-induced cardiomyopathy, and provide insight into areas requiring further investigation.

Integration of single-cell transcriptomics and epigenetic analysis reveals enhancer-controlled TIMP1 as a regulator of ferroptosis in colorectal cancer

BACKGROUND

Ferroptosis is an iron-dependent non-apoptotic programmed cell death. However, the regulatory mechanism of ferroptosis in colorectal cancer (CRC) is still unclear.

OBJECTIVE

The aim of this study was to investigate the role and mechanism of enhancer-controlled genes in ferroptosis in CRC.

METHODS

Dimensionality reduction and differentially expressed genes (DEGs) identification were conducted using Seurat algorithm based on single-cell RNA sequencing (scRNA-seq) data from the GSE200997 dataset. Ferroptosis-related pathway enrichment analysis was performed using the FerrDb V2 database. Enhancers were identified using HOMER algorithm based on H3K27ac ChIP-seq data from the GSE166254 dataset. Kaplan-Meier Plotter online tool was used to analyze prognosis and gene expression correlation. Transcription factors were predicted using the transcription factor affinity prediction web tool. The binding of enhancer to transcription factor and H3K27ac enrichment were detected by ChIP-qPCR. RSL3 was used to induce ferroptosis in CRC cells. Gene transcription was detected by qRT-PCR. Cell proliferation was detected by CCK8 assay.

RESULTS

Nine cell clusters including T cells, natural killer cells, macrophages, mast cells, epithelial cells, fibroblasts, goblet cells, B cells and dendritic cells were identified in CRC and normal colonic tissue samples. Compared to normal colonic tissue-derived epithelial cells, 1075 DEGs were screened in CRC tissue-derived epithelial cells. Ferroptosis-related pathway enrichment suggested that DEGs were associated with the regulation of ferroptosis. DPEP1, ETV4, CEBPG, TIMP1, DUOX2 and LCN2 were identified as the significantly upregulated genes enriched in the "ferroptosis regulator" term, and their H3K27ac signals were significantly higher in CRC tissues than in normal colonic tissues. Of these, only the expression of TIMP1 predicted a poor prognosis of CRC patients. Transcription factor SPI1 drove TIMP1 transcription by binding to its enhancer. Overexpression of TIMP1 significantly promoted the resistance to ferroptosis induced by RSL3 in CRC cells, which was partially restored by SPI1 knockdown.

CONCLUSION

Transcription of TIMP1 was driven by transcription factor SPI1 in combination with its enhancer, consequently promoting CRC cells against ferroptosis. The SPI1/TIMP1 axis confers ferroptosis resistance in CRC, and thus has the potential to be the molecular targets for CRC treatment.

Advances in regulation and function of stearoyl-CoA desaturase 1 in cancer, from bench to bed

Stearoyl-CoA desaturase 1 (SCD1) converts saturated fatty acids to monounsaturated fatty acids. The expression of SCD1 is increased in many cancers, and the altered expression contributes to the proliferation, invasion, sternness and chemoresistance of cancer cells. Recently, more evidence has been reported to further support the important role of SCD1 in cancer, and the regulation mechanism of SCD1 has also been focused. Multiple factors are involved in the regulation of SCD1, including metabolism, diet, tumor microenvironment, transcription factors, non-coding RNAs, and epigenetics modification. Moreover, SCD1 is found to be involved in regulating ferroptosis resistance. Based on these findings, SCD1 has been considered as a potential target for cancer treatment. However, the resistance of SCD1 inhibition may occur in certain tumors due to tumor heterogeneity and metabolic plasticity. This review summarizes recent advances in the regulation and function of SCD1 in tumors and discusses the potential clinical application of targeting SCD1 for cancer treatment.

NeuroD1-GPX4 signaling leads to ferroptosis resistance in hepatocellular carcinoma

Cell death resistance is a hallmark of tumor cells that drives tumorigenesis and drug resistance. Targeting cell death resistance-related genes to sensitize tumor cells and decrease their cell death threshold has attracted attention as a potential antitumor therapeutic strategy. However, the underlying mechanism is not fully understood. Recent studies have reported that NeuroD1, first discovered as a neurodifferentiation factor, is upregulated in various tumor cells and plays a crucial role in tumorigenesis. However, its involvement in tumor cell death resistance remains unknown. Here, we found that NeuroD1 was highly expressed in hepatocellular carcinoma (HCC) cells and was associated with tumor cell death resistance. We revealed that NeuroD1 enhanced HCC cell resistance to ferroptosis, a type of cell death caused by aberrant redox homeostasis that induces lipid peroxide accumulation, leading to increased HCC cell viability. NeuroD1 binds to the promoter of glutathione peroxidase 4 (GPX4), a key reductant that suppresses ferroptosis by reducing lipid peroxide, and activates its transcriptional activity, resulting in decreased lipid peroxide and ferroptosis. Subsequently, we showed that NeuroD1/GPX4-mediated ferroptosis resistance was crucial for HCC cell tumorigenic potential. These findings not only identify NeuroD1 as a regulator of tumor cell ferroptosis resistance but also reveal a novel molecular mechanism underlying the oncogenic function of NeuroD1. Furthermore, our findings suggest the potential of targeting NeuroD1 in antitumor therapy.

Autophagy/ferroptosis in colorectal cancer: Carcinogenic view and nanoparticle-mediated cell death regulation

The cell death mechanisms have a long history of being evaluated in diseases and pathological events. The ability of triggering cell death is considered to be a promising strategy in cancer therapy, but some mechanisms have dual functions in cancer, requiring more elucidation of underlying factors. Colorectal cancer (CRC) is a disease and malignant condition of colon and rectal that causes high mortality and morbidity. The autophagy targeting in CRC is therapeutic importance and this cell death mechanism can interact with apoptosis in inhibiting or increasing apoptosis. Autophagy has interaction with ferroptosis as another cell death pathway in CRC and can accelerate ferroptosis in suppressing growth and invasion. The dysregulation of autophagy affects the drug resistance in CRC and pro-survival autophagy can induce drug resistance. Therefore, inhibition of protective autophagy enhances chemosensitivity in CRC cells. Moreover, autophagy displays interaction with metastasis and EMT as a potent regulator of invasion in CRC cells. The same is true for ferroptosis, but the difference is that function of ferroptosis is determined and it can reduce viability. The lack of ferroptosis can cause development of chemoresistance in CRC cells and this cell death mechanism is regulated by various pathways and mechanisms that autophagy is among them. Therefore, current review paper provides a state-of-art analysis of autophagy, ferroptosis and their crosstalk in CRC. The nanoparticle-mediated regulation of cell death mechanisms in CRC causes changes in progression. The stimulation of ferroptosis and control of autophagy (induction or inhibition) by nanoparticles can impair CRC progression. The engineering part of nanoparticle synthesis to control autophagy and ferroptosis in CRC still requires more attention.

Curcumin induces ferroptosis and apoptosis in osteosarcoma cells by regulating Nrf2/GPX4 signaling pathway

Curcumin, an antitumor agent, has been shown to inhibit cell growth and metastasis in osteosarcoma. However, there is no evidence of curcumin and its regulation of cell ferroptosis and nuclear factor E2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPX4) signaling pathways in osteosarcoma. This study aimed to investigate the effects of curcumin on osteosarcoma both in vitro and in vivo. To explore the effects and mechanisms of curcumin on osteosarcoma, cells (MNNG/HOS and MG-63) and xenograft mice models were established. Cell viability, cell apoptosis rate, cycle distribution, cell migration, cell invasion, reactive oxygen species, malonaldehyde and glutathione abilities, and protein levels were detected by cell counting kit-8, flow cytometry, wound healing, transwell assay, respectively. Nrf2 and GPX4 expressions were detected using an immunofluorescence assay. Nrf2/GPX4-related protein levels were detected using western blotting. The results showed that curcumin effectively decreased cell viability and increased apoptosis rate. Meanwhile, curcumin inhibited tumor volume in the xenograft model, and Nrf2/GPX4-related protein levels were also altered. Interestingly, the effects of curcumin were reversed by liproxstatin-1 (an effective inhibitor of ferroptosis) and bardoxolone-methyl (an effective activator of Nrf2). Our results indicate that curcumin has therapeutic effects on osteosarcoma cells and a xenograft model by regulating the expression of the Nrf2/GPX4 signaling pathway.

Impact of curcumin on ferroptosis-related genes in colorectal cancer: Insights from in-silico and in-vitro studies

Colorectal cancer (CRC) is responsible for a significant number of cancer-related fatalities worldwide. Researchers are investigating the therapeutic potential of ferroptosis, a type of iron-dependent controlled cell death, in the context of CRC. Curcumin, a natural compound found in turmeric, exhibits anticancer properties. This study explores the effects of curcumin on genes related to ferroptosis (FRGs) in CRC. To gather CRC data, we used the Gene Expression Profiling Interactive Analysis (GEPIA) and Gene Expression Omnibus (GEO) databases, while FRGs were obtained from the FerrDb database and PubMed. We identified 739 CRC differentially expressed genes (DEGs) in CRC and discovered 39 genes that were common genes between FRGs and CRC DEGs. The DEGs related to ferroptosis were enriched with various biological processes and molecular functions, including the regulation of signal transduction and glucose metabolism. Using the Drug Gene Interaction Database (DGIdb), we predicted drugs targeting CRC-DEGs and identified 17 potential drug targets. Additionally, we identified eight essential proteins related to ferroptosis in CRC, including MYC, IL1B, and SLC1A5. Survival analysis revealed that alterations in gene expression of CDC25A, DDR2, FABP4, IL1B, SNCA, and TFAM were associated with prognosis in CRC patients. In SW480 human CRC cells, treatment with curcumin decreased the expression of MYC, IL1B, and EZH2 mRNA, while simultaneously increasing the expression of SLCA5 and CAV1. The findings of this study suggest that curcumin could regulate FRGs in CRC and have the potential to be utilized as a therapeutic agent for treating CRC.

Anaplastic thyroid cancer cells reduce CD71 levels to increase iron overload tolerance

BACKGROUND

Follicular thyroid cancer (FTC) is a prevalent form of differentiated thyroid cancer, whereas anaplastic thyroid cancer (ATC) represents a rare, fast-growing, undifferentiated, and highly aggressive tumor, posing significant challenges for eradication. Ferroptosis, an iron-dependent cell death mechanism driven by the excessive production of reactive oxygen species and subsequent lipid peroxidation, emerges as a promising therapeutic strategy for cancer. It has been observed that many cancer cells exhibit sensitivity to ferroptosis, while some other histotypes appear to be resistant, by counteracting the metabolic changes and oxidative stress induced by iron overload.

METHODS

Here we used human biopsies and in vitro approaches to analyse the effects of iron-dependent cell death. We assessed cell proliferation and viability through MTT turnover, clonogenic assays, and cytofluorimetric-assisted analysis. Lipid peroxidation assay and western blot were used to analyse molecular mechanisms underlying ferroptosis modulation. Two distinct thyroid cancer cell lines, FTC-133 (follicular) and 8505C (anaplastic), were utilized. These cell lines were exposed to ferroptosis inducers, Erastin and RSL3, while simulating an iron overload condition using ferric ammonium citrate.

RESULTS

Our evidence suggests that FTC-133 cell line, exposed to iron overload, reduced their viability and showed increased ferroptosis. In contrast, the 8505C cell line seems to better tolerate ferroptosis, responding by modulating CD71, which is involved in iron internalization and seems to have a role in resistance to iron overload and consequently in maintaining cell viability.

CONCLUSIONS

The differential tolerance to ferroptosis observed in our study may hold clinical implications, particularly in addressing the unmet therapeutic needs associated with ATC treatment, where resistance to ferroptosis appears more pronounced compared to FTC.

B7H3 increases ferroptosis resistance by inhibiting cholesterol metabolism in colorectal cancer

Ferroptosis, a newly discovered form of regulated cell death, has been reported to be associated with multiple cancers, including colorectal cancer (CRC). However, the underlying molecular mechanism is still unclear. In this study, we identified B7H3 as a potential regulator of ferroptosis resistance in CRC. B7H3 knockdown decreased but B7H3 overexpression increased the ferroptosis resistance of CRC cells, as evidenced by the expression of ferroptosis-associated genes (PTGS2, FTL, FTH, and GPX4) and the levels of important indicators of ferroptosis (malondialdehyde, iron load). Moreover, B7H3 promoted ferroptosis resistance by regulating sterol regulatory element binding protein 2 (SREBP2)-mediated cholesterol metabolism. Both exogenous cholesterol supplementation and treatment with the SREBP2 inhibitor betulin reversed the effect of B7H3 on ferroptosis in CRC cells. Furthermore, we verified that B7H3 downregulated SREBP2 expression by activating the AKT pathway. Additionally, multiplex immunohistochemistry was carried out to show the expression of B7H3, prostaglandin-endoperoxide synthase 2, and SREBP2 in CRC tumor tissues, which was associated with the prognosis of patients with CRC. In summary, our findings reveal a role for B7H3 in regulating ferroptosis by controlling cholesterol metabolism in CRC.

Harnessing Ferroptosis to Overcome Drug Resistance in Colorectal Cancer: Promising Therapeutic Approaches

Drug resistance remains a significant challenge in the treatment of colorectal cancer (CRC). In recent years, the emerging field of ferroptosis, a unique form of regulated cell death characterized by iron-dependent lipid peroxidation, has offered new insights and potential therapeutic strategies for overcoming drug resistance in CRC. This review examines the role of ferroptosis in CRC and its impact on drug resistance. It highlights the distinctive features and advantages of ferroptosis compared to other cell death pathways, such as apoptosis and necrosis. Furthermore, the review discusses current research advances in the field, including novel treatment approaches that target ferroptosis. These approaches involve the use of ferroptosis inducers, interventions in iron metabolism and lipid peroxidation, and combination therapies to enhance the efficacy of ferroptosis. The review also explores the potential of immunotherapy in modulating ferroptosis as a therapeutic strategy. Additionally, it evaluates the strengths and limitations of targeting ferroptosis, such as its selectivity, low side effects, and potential to overcome resistance, as well as challenges related to treatment specificity and drug development. Looking to the future, this review discusses the prospects of ferroptosis-based therapies in CRC, emphasizing the importance of further research to elucidate the interaction between ferroptosis and drug resistance. It proposes future directions for more effective treatment strategies, including the development of new therapeutic approaches, combination therapies, and integration with emerging fields such as precision medicine. In conclusion, harnessing ferroptosis represents a promising avenue for overcoming drug resistance in CRC. Continued research efforts in this field are crucial for optimizing therapeutic outcomes and providing hope for CRC patients.

Targeting Ferroptosis in Bone-Related Diseases: Facts and Perspectives

Ferroptosis is a new cell fate decision discovered in recent years. Unlike apoptosis, autophagy or pyroptosis, ferroptosis is characterized by iron-dependent lipid peroxidation and mitochondrial morphological changes. Ferroptosis is involved in a variety of physiological and pathological processes. Since its discovery, ferroptosis has been increasingly studied concerning bone-related diseases. In this review, we focus on the latest research progress and prospects, summarize the regulatory mechanisms of ferroptosis, and discuss the role of ferroptosis in the pathogenesis of bone-related diseases, such as osteoporosis (OP), osteoarthritis (OA), rheumatoid arthritis (RA), and osteosarcoma (OS), as well as its therapeutic potential.

The mechanism of ferroptosis and its related diseases

Ferroptosis, a regulated form of cellular death characterized by the iron-mediated accumulation of lipid peroxides, provides a novel avenue for delving into the intersection of cellular metabolism, oxidative stress, and disease pathology. We have witnessed a mounting fascination with ferroptosis, attributed to its pivotal roles across diverse physiological and pathological conditions including developmental processes, metabolic dynamics, oncogenic pathways, neurodegenerative cascades, and traumatic tissue injuries. By unraveling the intricate underpinnings of the molecular machinery, pivotal contributors, intricate signaling conduits, and regulatory networks governing ferroptosis, researchers aim to bridge the gap between the intricacies of this unique mode of cellular death and its multifaceted implications for health and disease. In light of the rapidly advancing landscape of ferroptosis research, we present a comprehensive review aiming at the extensive implications of ferroptosis in the origins and progress of human diseases. This review concludes with a careful analysis of potential treatment approaches carefully designed to either inhibit or promote ferroptosis. Additionally, we have succinctly summarized the potential therapeutic targets and compounds that hold promise in targeting ferroptosis within various diseases. This pivotal facet underscores the burgeoning possibilities for manipulating ferroptosis as a therapeutic strategy. In summary, this review enriched the insights of both investigators and practitioners, while fostering an elevated comprehension of ferroptosis and its latent translational utilities. By revealing the basic processes and investigating treatment possibilities, this review provides a crucial resource for scientists and medical practitioners, aiding in a deep understanding of ferroptosis and its effects in various disease situations.

Cis-monounsaturated fatty acids inhibit ferroptosis through downregulation of transferrin receptor 1

Ferroptosis, a form of cell death mediated by lipid peroxidation, is implicated in various pathological processes. Although monounsaturated fatty acids (MUFAs) can inhibit ferroptotic lipid peroxidation, the underlying structural mechanism of this antagonistic effect remains poorly understood. We hypothesized that MUFAs with different structures (including chain length, conformation, and double bond position) may affect their regulatory effect on ferroptosis. In this study, 11 MUFAs with varying structures were screened to identify those with an inhibitory effect on ferroptosis. Results from 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazoliumbromide assays indicated that only exogenous MUFAs with cis-conformation and centered double bond could inhibit ferroptosis. Meanwhile, it was found that suppressing the expression of SCD1 and SCD5 genes could sensitize cells to ferroptosis indicating the protective role of endogenous MUFA against ferroptosis. Additionally, western blot analysis revealed that cis-MUFAs with centered double bond downregulated the protein levels of transferrin receptor 1. Flow cytometry confirmed that these MUFAs led to decreases in intracellular iron, reactive oxygen species, and lipid peroxides. It was also found that SCD1 inhibitor could enhance ferroptosis inducer-mediated tumor suppression both in vivo and in vitro. Overall, these findings shed light on the particular structural features of MUFAs that contribute to their ferroptosis-resistant properties and suggest the potential therapeutic relevance of natural MUFAs in a range of ferroptosis-related diseases.

The Emerging Roles of Ferroptosis in Pathophysiology and Treatment of Acute Lung Injury

Ferroptosis, a programmed cell death discovered in recent years, is an iron-dependent lipid peroxidation accumulation. Unlike other modes of cell death (autophagy, necroptosis, pyroptosis, cuproptosis, etc.), ferroptosis has unique morphological characteristics and plays an important role in a variety of diseases. In recent years, there has been great progress in the study of ferroptosis. Studies have found that ferroptosis is associated with acute lung injury (ALI), a condition with a high mortality rate and limited treatment options. This paper summarizes the mechanism of ferroptosis from the perspectives of iron metabolism, lipid metabolism, amino acid metabolism, and glutathione metabolism. It also discusses the research progress of ferroptosis in ALI in order to find new directions for the prevention and treatment of this condition.

Ferroptosis, Necroptosis, and Pyroptosis in Gastrointestinal Cancers: The Chief Culprits of Tumor Progression and Drug Resistance

In recent years, the incidence of gastrointestinal cancers is increasing, particularly in the younger population. Effective treatment is crucial for improving patients' survival outcomes. Programmed cell death, regulated by various genes, plays a fundamental role in the growth and development of organisms. It is also critical for maintaining tissue and organ homeostasis and takes part in multiple pathological processes. In addition to apoptosis, there are other types of programmed cell death, such as ferroptosis, necroptosis, and pyroptosis, which can induce severe inflammatory responses. Notably, besides apoptosis, ferroptosis, necroptosis, and pyroptosis also contribute to the occurrence and development of gastrointestinal cancers. This review aims to provide a comprehensive summary on the biological roles and molecular mechanisms of ferroptosis, necroptosis, and pyroptosis, as well as their regulators in gastrointestinal cancers and hope to open up new paths for tumor targeted therapy in the near future.

Atherosclerosis, Diabetes Mellitus, and Cancer: Common Epidemiology, Shared Mechanisms, and Future Management

The involvement of cardiovascular disease in cancer onset and development represents a contemporary interest in basic science. It has been recognized, from the most recent research, that metabolic syndrome-related conditions, ranging from atherosclerosis to diabetes, elicit many pathways regulating lipid metabolism and lipid signaling that are also linked to the same framework of multiple potential mechanisms for inducing cancer. Otherwise, dyslipidemia and endothelial cell dysfunction in atherosclerosis may present common or even interdependent changes, similar to oncogenic molecules elevated in many forms of cancer. However, whether endothelial cell dysfunction in atherosclerotic disease provides signals that promote the pre-clinical onset and proliferation of malignant cells is an issue that requires further understanding, even though more questions are presented with every answer. Here, we highlight the molecular mechanisms that point to a causal link between lipid metabolism and glucose homeostasis in metabolic syndrome-related atherosclerotic disease with the development of cancer. The knowledge of these breakthrough mechanisms may pave the way for the application of new therapeutic targets and for implementing interventions in clinical practice.

Interaction mechanisms between autophagy and ferroptosis: Potential role in colorectal cancer

Colorectal cancer (CRC) is a common malignancy that has the second highest incidence and mortality rate. Although there are many personalized treatment options for CRC, the therapeutic effects are ultimately limited by drug resistance. Studies have aimed to block the initiation and progression of CRC by inducing cell death to overcome this obstacle. Substantial evidence has indicated that both autophagy and ferroptosis play important regulatory roles in CRC. Autophagy, a lysosome-dependent process by which cellular proteins and organelles are degraded, is the basic mechanism for maintaining cell homeostasis. The duality and complexity of autophagy in cancer therapy is a hot topic of discussion. Ferroptosis, a regulated cell death pathway, is associated with iron accumulation-induced lipid peroxidation. The activation of ferroptosis can suppress CRC proliferation, invasion and drug resistance. Furthermore, recent studies have suggested an interaction between autophagy and ferroptosis. Autophagy can selectively degrade certain cellular contents to provide raw materials for ferroptosis, ultimately achieving antitumor and anti-drug resistance. Therefore, exploring the interaction between autophagy and ferroptosis could reveal novel ideas for the treatment of CRC. In this review, we describe the mechanisms of autophagy and ferroptosis, focusing on their roles in CRC and the crosstalk between them.

The Induction Mechanism of Ferroptosis, Necroptosis, and Pyroptosis in Inflammatory Bowel Disease, Colorectal Cancer, and Intestinal Injury

Cell death includes programmed and nonprogrammed cell death. The former mainly includes ferroptosis, necroptosis, pyroptosis, autophagy, and apoptosis, while the latter refers to necrosis. Accumulating evidence shows that ferroptosis, necroptosis, and pyroptosis play essential regulatory roles in the development of intestinal diseases. In recent years, the incidence of inflammatory bowel disease (IBD), colorectal cancer (CRC), and intestinal injury induced by intestinal ischemia-reperfusion (I/R), sepsis, and radiation have gradually increased, posing a significant threat to human health. The advancement in targeted therapies for intestinal diseases based on ferroptosis, necroptosis, and pyroptosis provides new strategies for treating intestinal diseases. Herein, we review ferroptosis, necroptosis, and pyroptosis with respect to intestinal disease regulation and highlight the underlying molecular mechanisms for potential therapeutic applications.

DNA methylation of RUNX3 promotes the progression of gallbladder cancer through repressing SLC7A11-mediated ferroptosis

Gallbladder cancer (GBC) is a type of rare but highly aggressive cancer with a dismal prognosis. Runt-related transcription factor 3 (RUNX3), a member of the runt-domain family, and its promoter methylation have been widely observed in a variety of human malignancies. However, the biological function and underlying mechanism of RUNX3 in GBC remain elusive. In this study, bisulfate sequencing PCR (BSP), Western blot, and qPCR were applied to identify the expression level and DNA methylation level of RUNX3 in GBC tissues and cells. The transcriptional relationship between RUNX3 and Inhibitor of growth 1 (ING1) was validated by dual-luciferase reporter assay and ChIP assay. A series of gain-of-function and loss-of-function assays were performed to detect the function and the regulatory relationship of RUNX3 in vitro and in vivo. RUNX3 was aberrantly downregulated in GBC cells and tissues caused by DNA Methyltransferase 1 (DNMT1)-mediated methylation, and downregulation of RUNX3 is associated with poor prognosis of GBC patients. Functional experiments reveal that RUNX3 can induce ferroptosis of GBC cells in vitro and in vivo. Mechanistically, RUNX3 induces ferroptosis by activating ING1 transcription, thereby repressing SLC7A11 in a p53-dependent manner. In conclusion, the downregulation of RUNX3 is mediated by DNA methylation, which promotes the pathogenesis of gallbladder cancer through attenuating SLC7A11-mediated ferroptosis. This study gives novel insights into the role of RUNX3 in the ferroptosis of GBC cells, which may contribute to developing potential treatment targets for GBC.

TIGAR protects against adenine-induced ferroptosis in human proximal tubular epithelial cells by activating the mTOR/S6KP70 axis

TP53-induced glycolysis and apoptosis regulator (TIGAR) acts as a switch for nephropathy, but its underlying mechanism is still unclear. The purpose of this study was to explore the potential biological significance and underlying mechanism of TIGAR in modulating adenine-induced ferroptosis in human proximal tubular epithelial (HK-2) cells. HK-2 cells under- or overexpressing TIGAR were challenged with adenine to induce ferroptosis. The levels of reactive oxygen species (ROS), iron, malondialdehyde (MDA), and glutathione (GSH) were assayed. Expression of ferroptosis-associated solute carrier family seven-member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) at the level of mRNA and protein were measured by quantitative real-time-PCR and western blotting. The phosphorylation levels of proteins in the mTOR/S6KP70 pathway were determined by western blotting. Adenine overload triggered ferroptosis in HK-2 cells, as evidenced by reduced levels of GSH, SLC7A11, and GPX4, and increased levels of iron, MDA, and ROS. TIGAR overexpression repressed adenine-induced ferroptosis and induced mTOR/S6KP70 signaling. Inhibitors of mTOR and S6KP70 weakened the ability of TIGAR to inhibit adenine-induced ferroptosis. TIGAR inhibits adenine-induced ferroptosis in human proximal tubular epithelial cells by activating the mTOR/S6KP70 signaling pathway. Therefore, activating the TIGAR/mTOR/S6KP70 axis may be a treatment for crystal nephropathies.

Ferroptosis in gastrointestinal cancer: From mechanisms to implications

Ferroptosis is a form of regulated cell death that is initiated by excessive lipid peroxidation that results in plasma membrane damage and the release of damage-associated molecular patterns. In recent years, ferroptosis has gained significant attention in cancer research due to its unique mechanism compared to other forms of regulated cell death, especially caspase-dependent apoptotic cell death. Gastrointestinal (GI) cancer encompasses malignancies that arise in the digestive tract, including the stomach, intestines, pancreas, colon, liver, rectum, anus, and biliary system. These cancers are a global health concern, with high incidence and mortality rates. Despite advances in medical treatments, drug resistance caused by defects in apoptotic pathways remains a persistent challenge in the management of GI cancer. Hence, exploring the role of ferroptosis in GI cancers may lead to more efficacious treatment strategies. In this review, we provide a comprehensive overview of the core mechanism of ferroptosis and discuss its function, regulation, and implications in the context of GI cancers.

Mechanism and application of ferroptosis in colorectal cancer

Colorectal cancer (CRC) is the third most common malignant tumor in the world. CRC has high morbidity and mortality rates and it is a serious threat to human health. Ferroptosis is a unique form of iron-dependent oxidative cell death that is usually accompanied by iron accumulation and lipid peroxidation. Ferroptosis has attracted worldwide attention since it was first proposed. It plays an important role in the development of a variety of diseases, such as tumors, ischemia/reperfusion injury, nervous system diseases, and kidney damage, and it may serve as a new therapeutic target. This article reviews the mechanism of ferroptosis and the possibility to target ferroptosis pathways in CRC, providing new ideas for the diagnosis and treatment of CRC.

Review of ferroptosis in colorectal cancer: Friends or foes?

Ferroptosis is a newly discovered type of cell-regulated death. It is characterized by the accumulation of iron-dependent lipid peroxidation and can be distinguished from other forms of cell-regulated death by different morphology, biochemistry, and genetics. Recently, studies have shown that ferroptosis is associated with a variety of diseases, including liver, kidney and neurological diseases, as well as cancer. Ferroptosis has been shown to be associated with colorectal epithelial disorders, which can lead to cancerous changes in the gut. However, the potential role of ferroptosis in the occurrence and development of colorectal cancer (CRC) is still controversial. To elucidate the underlying mechanisms of ferroptosis in CRC, this article systematically reviews ferroptosis, and its cellular functions in CRC, for furthering the understanding of the pathogenesis of CRC to aid clinical treatment.

Targeting critical pathways in ferroptosis and enhancing antitumor therapy of Platinum drugs for colorectal cancer

Colorectal cancer (CRC) can be resistant to platinum drugs, possibly through ferroptosis suppression, albeit the need for further work to completely understand this mechanism. This work aimed to sum up current findings pertaining to oxaliplatin resistance (OR) or resistance to ascertain the potential of ferroptosis to regulate oxaliplatin effects. In this review, tumor development relating to iron homeostasis, which includes levels of iron that ascertain cells' sensitivity to ferroptosis, oxidative stress, or lipid peroxidation in colorectal tumor cells that are connected with ferroptosis initiation, especially the role of c-Myc/NRF2 signaling in regulating iron homeostasis, coupled with NRF2/GPX4-mediated ferroptosis are discussed. Importantly, ferroptosis plays a key role in OR and ferroptotic induction may substantially reverse OR in CRC cells, which in turn could inhibit the imbalance of intracellular redox induced by oxaliplatin and ferroptosis, as well as cause chemotherapeutic resistance in CRC. Furthermore, fundamental research of small molecules, ferroptosis inducers, GPX4 inhibitors, or natural products for OR coupled with their clinical applications in CRC have also been summarized. Also, potential molecular targets and mechanisms of small molecules or drugs are discussed as well. Suggestively, OR of CRC cells could significantly be reversed by ferroptosis induction, wherein this result is discussed in the current review. Prospectively, the existing literature discussed in this review will provide a solid foundation for scientists to research the potential use of combined anticancer drugs which can overcome OR via targeting various mechanisms of ferroptosis. Especially, promising therapeutic strategies, challenges ,and opportunities for CRC therapy will be discussed.

Insights on Ferroptosis and Colorectal Cancer: Progress and Updates

Patients with advanced-stage or treatment-resistant colorectal cancer (CRC) benefit less from traditional therapies; hence, new therapeutic strategies may help improve the treatment response and prognosis of these patients. Ferroptosis is an iron-dependent type of regulated cell death characterized by the accumulation of lipid reactive oxygen species (ROS), distinct from other types of regulated cell death. CRC cells, especially those with drug-resistant properties, are characterized by high iron levels and ROS. This indicates that the induction of ferroptosis in these cells may become a new therapeutic approach for CRC, particularly for eradicating CRC resistant to traditional therapies. Recent studies have demonstrated the mechanisms and pathways that trigger or inhibit ferroptosis in CRC, and many regulatory molecules and pathways have been identified. Here, we review the current research progress on the mechanism of ferroptosis, new molecules that mediate ferroptosis, including coding and non-coding RNA; novel inducers and inhibitors of ferroptosis, which are mainly small-molecule compounds; and newly designed nanoparticles that increase the sensitivity of cells to ferroptosis. Finally, the gene signatures and clusters that have predictive value on CRC are summarized.

Targeting Ferroptosis in Colorectal Cancer

Ferroptosis is a unique way of regulating cell death (RCD), which is quite different from other programmed cell deaths such as autophagy. It presents iron overload, accumulation of reactive oxygen species (ROS), and lipid peroxidation. A ferroptotic cell usually has an intact cell structure as well as shrinking mitochondria with decreased or vanishing cristae, concentrated membrane density, and ruptured outer membrane. Recently, increasing investigations have discovered that tumor cells have a much greater iron demand than the normal ones, making them more sensitive to ferroptosis. In other words, ferroptosis may inhibit the progress of the tumor, which can be used in the therapy of tumor patients, especially for those with chemotherapy resistance. Therefore, ferroptosis has become one hot spot in the field of tumor research in recent years. Colorectal cancer (CRC) is one common type of gastrointestinal malignancy. The incidence of CRC appears to have an upward trend year by year since the enhancement of living standards. Although surgery and chemoradiotherapy have largely improved the prognosis of patients with CRC, some patients still appear to have severe adverse reactions and drug resistance. Moreover, much research has verified that ferroptosis has a necessary association with the occurrence and progression of gastrointestinal tumors. In this review, we provide a comprehensive evaluation of the main mechanisms of iron metabolism, lipid metabolism, and amino acid metabolism involved in the occurrence of ferroptosis, as well as the research progress of ferroptosis in CRC.

Downregulation of HULC Induces Ferroptosis in Hepatocellular Carcinoma via Targeting of the miR-3200-5p/ATF4 Axis

Hepatocellular carcinoma is a malignant tumor that poses a serious threat to human health. Ferroptosis, which represents an identified type of regulated iron-dependent cell death, may play an important role in hepatocellular carcinoma. However, it is unclear as to whether ferroptosis is involved with the mechanisms of lncRNA HULC in liver cancer cells. Here, we show that knockdown of HULC increases ferroptosis and oxidative stress in liver cancer cells. We also found changes in some related miRNAs in cells treated with HULC siRNA. Differential miRNA expression levels were determined with the use of high-throughput sequencing and prediction target genes identified using bioinformatics analysis. HULC was found to function as a ceRNA of miR-3200-5p, and miR-3200-5p regulates ferroptosis by targeting ATF4, resulting in the inhibition of proliferation and metastasis within HCC cells. In summary, these findings illuminate some of the molecular mechanisms through which downregulation of HULC induces liver cancer cell ferroptosis by targeting the miR-3200-5p/ATF4 axis to modulate the development of hepatocellular carcinoma.