Persister cell plasticity in tumour drug resistance

The emergence of therapeutic resistance remains a formidable barrier to durable responses by cancer patients and is a major cause of cancer-related deaths. It is increasingly recognized that non-genetic mechanisms of acquired resistance are important in many cancers. These mechanisms of resistance rely on inherent cellular plasticity where cancer cells can switch between multiple phenotypic states without genetic alterations, providing a dynamic, reversible resistance landscape. Such mechanisms underlie the generation of drug-tolerant persister (DTP) cells, a subpopulation of tumour cells that contributes to heterogeneity within tumours and that supports therapeutic resistance. In this review, we provide an overview of the major features of DTP cells, focusing on phenotypic and metabolic plasticity as two key drivers of tolerance and persistence. We discuss the link between DTP cell plasticity and the potential vulnerability of these cells to ferroptosis. We also discuss the relationship between DTP cells and cells that survive the induction of apoptosis, a process termed anastasis, and discuss the properties of such cells in the context of increased metastatic potential and sensitivity to cell death mechanisms such as ferroptosis.

Selective induction of programmed cell death using synthetic biology tools

Regulated cell death (RCD) controls the removal of dispensable, infected or malignant cells, and is thus essential for development, homeostasis and immunity of multicellular organisms. Over the last years different forms of RCD have been described (among them apoptosis, necroptosis, pyroptosis and ferroptosis), and the cellular signaling pathways that control their induction and execution have been characterized at the molecular level. It has also become apparent that different forms of RCD differ in their capacity to elicit inflammation or an immune response, and that RCD pathways show a remarkable plasticity. Biochemical and genetic studies revealed that inhibition of a given pathway often results in the activation of back-up cell death mechanisms, highlighting close interconnectivity based on shared signaling components and the assembly of multivalent signaling platforms that can initiate different forms of RCD. Due to this interconnectivity and the pleiotropic effects of 'classical' cell death inducers, it is challenging to study RCD pathways in isolation. This has led to the development of tools based on synthetic biology that allow the targeted induction of RCD using chemogenetic or optogenetic methods. Here we discuss recent advances in the development of such toolset, highlighting their advantages and limitations, and their application for the study of RCD in cells and animals.

TMT quantitative proteomics analysis reveals molecular mechanism of ferroptosis during beef refrigeration

Ferroptosis is a recently identified cell death process in refrigerated beef, and its mediated protein oxidation and cell death may reduce muscle quality, but the mechanism of ferroptosis is unclear. In the study, free iron accumulation reached 19.670 ± 0.482 μg/g after 6 days refrigeration, the levels of apoptosis, ROS, and lipid peroxidation increased significantly (P < 0.05), and muscle tissue cells exhibited typical ferroptosis characteristics. A total of 377 differentially expressed proteins (DEPs) were identified by TMT quantitative proteomics. 15 DEPs, including transferrin, ferritin, glutathione peroxidase (GPX) 4, and heme oxygenase 1, were involved in lipid peroxidation, Fe2+ and Fe3+ conversion, iron ion accumulation, and mitochondrial oxidative stress to induce ferroptosis. In addition, signalling pathways, such as chemical carcinogenesis-ROS, glutathione metabolism, HIF-1, and PPAR may promote ferroptosis by affecting free iron overload and GPX4 inactivation.

Simvastatin/hydrogel-loaded 3D-printed titanium alloy scaffolds suppress osteosarcoma via TF/NOX2-associated ferroptosis while repairing bone defects

Postoperative anatomical reconstruction and prevention of local recurrence after tumor resection are two vital clinical challenges in osteosarcoma treatment. A three-dimensional (3D)-printed porous Ti6Al4V scaffold (3DTi) is an ideal material for reconstructing critical bone defects with numerous advantages over traditional implants, including a lower elasticity modulus, stronger bone-implant interlock, and larger drug-loading space. Simvastatin is a multitarget drug with anti-tumor and osteogenic potential; however, its efficiency is unsatisfactory when delivered systematically. Here, simvastatin was loaded into a 3DTi using a thermosensitive poly (lactic-co-glycolic) acid (PLGA)-polyethylene glycol (PEG)-PLGA hydrogel as a carrier to exert anti-osteosarcoma and osteogenic effects. Newly constructed simvastatin/hydrogel-loaded 3DTi (Sim-3DTi) was comprehensively appraised, and its newfound anti-osteosarcoma mechanism was explained. Specifically, in a bone defect model of rabbit condyles, Sim-3DTi exhibited enhanced osteogenesis, bone in-growth, and osseointegration compared with 3DTi alone, with greater bone morphogenetic protein 2 expression. In our nude mice model, simvastatin loading reduced tumor volume by 59%-77 % without organic damage, implying good anti-osteosarcoma activity and biosafety. Furthermore, Sim-3DTi induced ferroptosis by upregulating transferrin and nicotinamide adenine dinucleotide phosphate oxidase 2 levels in osteosarcoma both in vivo and in vitro. Sim-3DTi is a promising osteogenic bone substitute for osteosarcoma-related bone defects, with a ferroptosis-mediated anti-osteosarcoma effect.

PM2.5 exposure exacerbates seizure symptoms and cognitive dysfunction by disrupting iron metabolism and the Nrf2-mediated ferroptosis pathway

In recent years, air pollution has garnered global attention due to its ability to traverse borders and regions, thereby impacting areas far removed from the emission sources. While prior studies predominantly focused on the deleterious effects of PM2.5 on the respiratory and cardiovascular systems, emerging evidence has highlighted the potential risks of PM2.5 exposure to the central nervous system. Nonetheless, research elucidating the potential influences of PM2.5 exposure on seizures, specifically in relation to neuronal ferroptosis, remains limited. In this study, we investigated the potential effects of PM2.5 exposure on seizure symptoms and seizures-induced hippocampal neuronal ferroptosis. Our findings suggest that seizure patients residing in regions with high PM2.5 levels are more likely to disturb iron homeostasis and the Nrf2 dependent ferroptosis pathway compared to those living in areas with lower PM2.5 levels. The Morris Water Maze test, Racine scores, and EEG recordings in epileptic mice suggest that PM2.5 exposure can exacerbate seizure symptoms and cognitive dysfunction. Neurotoxic effects of PM2.5 exposure were demonstrated via Nissl staining and CCK-8 assays. Direct evidence of PM2.5-induced hippocampal neuronal ferroptosis was provided through TEM images. Additionally, increased Fe2+ and lipid ROS levels indirectly supported the notion of PM2.5-induced hippocampal ferroptosis. Therefore, our study underscores the necessity of preventing and controlling PM2.5 levels, particularly for patients with seizures.

Supramolecular self-assembly of EGCG-selenomethionine nanodrug for treating osteoarthritis

Osteoarthritis (OA) has emerged as a significant health concern among the elderly population, with increasing attention paid to ferroptosis-induced OA in recent years. However, the prolonged use of nonsteroidal anti-inflammatory drugs or corticosteroids can lead to a series of side effects and limited therapeutic efficacy. This study aimed to employ the Mannich condensation reaction between epigallocatechin-3-gallate (EGCG) and selenomethionine (SeMet) to efficiently synthesize polyphenol-based nanodrugs in aqueous media for treating OA. Molecular biology experiments demonstrated that EGCG-based nanodrugs (ES NDs) could effectively reduce glutathione peroxidase 4 (GPX4) inactivation, abnormal Fe2+ accumulation, and lipid peroxidation induced by oxidative stress, which ameliorated the metabolic disorder of chondrocytes and other multiple pathological processes triggered by ferroptosis. Moreover, imaging and histopathological analysis of the destabilization of the medial meniscus model in mice confirmed that ES NDs exhibiting significant therapeutic effects in relieving OA. The intra-articular delivery of ES NDs represents a promising approach for treating OA and other joint inflammatory diseases.

Buddlejasaponin IVb ameliorates ferroptosis of dopaminergic neuron by suppressing IRP2-mediated iron overload in Parkinson's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Parkinson's disease (PD) is the second neurodegenerative disease that lacks effective treatments. Buddlejasaponin IVb (BJP-IVb) is the main bioactive component of herbs in genus Clinopodium which display antioxidative, anti-inflammatory and neuroprotective activities. However, the role of BJP-IVb in PD still remains unknown.

AIM OF THE STUDY

This study aimed to evaluate the effect of BJP-IVb on dopaminergic neurodegeneration in PD and clarified the underlying mechanisms from the aspect of iron overload-mediated ferroptosis.

MATERIALS AND METHODS

One-methyl-4-phenylpyridinium (MPP+) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD models were established in this study. Behavioral tests, cell cytotoxicity assay, tyrosine hydroxylase (TH) and Nissl staining were performed to evaluate the antiparkinsonian effect of BJP-IVb. Cellular ultrastructure, iron content and lipid peroxidation were detected to evaluate iron overload-mediated dopaminergic neuron ferroptosis. Iron regulatory protein 2 (IRP2) and iron transport-related proteins were detected by immunofluorescence and Western blot to evaluated iron transport. Finally, plasmid vector-mediated IRP2 overexpression were performed to further clarify the molecular mechanism.

RESULTS

BJP-IVb alleviated MPP+-induced neurotoxicity in vitro and improved MPTP-induced dopaminergic neuron loss and motor dysfunctions of PD mice, confirming an effect of BJP-IVb against dopaminergic neurodegeneration of PD. Further results revealed that BJP-IVb protected against PD by suppressing iron overload-mediated dopaminergic neuron ferroptosis, as evidenced by the attenuated lipid peroxidation, decreased iron content and changes in cellular ultrastructure. Finally, the decreased iron regulatory protein (IRP2) was confirmed to be responsible for BJP-IVb-mediated ferroptosis suppression by modulating iron transport-related proteins and alleviating iron overload.

CONCLUSION

BJP-IVb suppressed iron overload-mediated dopaminergic neuron ferroptosis and improved motor dysfunctions in PD, which was achieved by inhibiting IRP2-mediated iron overload. This study provided a potential drug candidate for the treatment of PD.

Gastrodin alleviates cisplatin nephrotoxicity by inhibiting ferroptosis via the SIRT1/FOXO3A/GPX4 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Cisplatin (CP) results in acute kidney injury (AKI) and negatively affects patients' therapy and survival. The dried rhizome of Gastrodia elata Blume has been used to treat clinical kidney diseases. Gastrodin (GAS) is an active ingredient of the G. elata tuber. It is unknown whether GAS can alleviate CP-induced AKI.

AIM OF THE STUDY

This study aimed to investigate whether GAS, an active ingredient of G. elata Blume, can alleviate CP-induced AKI and to explore its underlying mechanisms.

MATERIALS AND METHODS

Experiments were conducted with a CP-induced AKI mouse model and an immortalized human renal tubular epithelial cell line (HK-2). Serum creatinine, Periodic acid-Schiff staining, tissue iron, glutathione, malondialdehyde, and 4-Hydroxynonenal were detected in serum and kidney samples to observe whether GAS inhibits CP-induced tubule ferroptosis. The drug target was verified by detecting the effects of GAS on sirtuin-1 (SIRT1) activity in vitro. Transcriptional regulation of glutathione peroxidase 4 (GPX4) by forkhead box O3A (FOXO3A) was verified by siRNA knockdown, overexpression, and chromatin immunoprecipitation. The effects of FOXO3A, SIRT1, and GAS on CP-induced ferroptosis were measured with propidium iodide, dihydroethidium, monobromobimane, and dipyrromethene boron difluoride staining in HK-2 cells. The relationship between GAS and the SIRT1/FOXO3A/GPX4 pathway was studied using Western blotting.

RESULTS

GAS treatment inhibited CP-induced reactive oxygen species, lipid peroxidation, and tubule death in the cell and animal models. GAS activated SIRT1 in vitro. The SIRT1 inhibitor blocked the protective role of GAS in reducing lipid peroxidation in HK-2 cells. FOXO3A transcriptionally regulated GPX4 expression and inhibited CP-induced cell ferroptosis. Compared to CP-damaged mouse kidneys, GAS-treated mice demonstrated significantly increased SIRT1 and GPX4 expression levels, decreased CP-induced acetylation of FOXO3A, and inhibited lipid peroxidation and cell death.

CONCLUSIONS

GAS alleviated CP-induced AKI by inhibiting ferroptosis via the SIRT1/FOXO3A/GPX4 signaling pathway. The results offer new insights into the development of new anti-AKI drugs from traditional Chinese medicine.

Di-Huang-Yin-Zi regulates P53/SLC7A11 signaling pathway to improve the mechanism of post-stroke depression

ETHNOPHARMACOLOGICAL RELEVANCE

Post-stroke depression (PSD) is a condition characterized by a profoundly depressed mood and diminished interest following a stroke. Di-Huang-Yin-Zi (DHYZ), a traditional Chinese herbal preparation, gained widespread use and shown favorable outcomes in PSD treatment. However, the combination mechanisms of this formula for PSD remain unclear.

AIM OF STUDY

This study aimed to assess the therapeutic effects of DHYZ extract on rats with PSD and further investigate its underlying mechanism.

MATERIALS AND METHODS

The active components of DHYZ extract were quantified by the high-performance liquid chromatography-ultraviolet (HPLC-UV). Neurofunctional and depressive-like behavioral tests were performed to assess the neuroprotective effects of DHYZ extract after establishing a PSD rat model. Brain tissue damage volume was assessed using TTC staining, and transmission electron microscopy (TEM) was used to observe the ultrastructural changes of neurons in the prefrontal cortex region, while cell apoptosis was evaluated through TUNEL assay in the prefrontal cortex region of the brain. The effect of DHYZ on ferroptosis markers includes Fe2+, malondialdehyde (MDA), reactive oxygen species (ROS), and glutathione (GSH) were determined in the brain tissue. Moreover, the expression of key proteins or mRNA levels of the P53/SLC7A11 signaling pathway were detected using Western blot or PCR, respectively. Additionally, P53-constructed overexpression vectors were injected to increase the level of P53. In this series of experiments, ferroptosis markers and key factors of the P53/SLC7A11 signaling pathway were evaluated.

RESULTS

DHYZ extract could increase the sucrose preference of SPT, but decrease the duration of immobility of FST and cortical infarct volume of PSD rats. A TEM study revealed that DHYZ extract improved synaptic ultrastructure in the cortical region of PSD rats. Furthermore, DHYZ treatment effectively decreased ROS and MDA levels, inhibiting the expression of ferroptosis-related markers such as Fe2+, SLC7A11, and GPX4. Additionally, DHYZ promoted the ubiquitination of P53, thus inhibiting its degradation. Notably, AAV-mediated overexpression of P53 reversed the effects of DHYZ on neuroprotection and ferroptosis inhibition in PSD rats.

CONCLUSIONS

Our results demonstrated that DHYZ extract alleviates the symptoms and enhances the functional capability of PSD rats, mainly by suppressing the ferroptosis through the P53/SLC7A11/GPX4 pathway.

In silico prediction and experimental validation to reveal the protective mechanism of Puerarin against excessive extracellular matrix accumulation through inhibiting ferroptosis in diabetic nephropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Puerarin (PUR) isolated from the root of Pueraria lobata (Willd.) Ohwi is considered as one of the main medicines to alleviate asthenic splenonephro-yang of diabetic nephropathy (DN). Whereas, the exact mechanism of Puerarin on diabetic nephropathy is still unclear.

AIM OF STUDY

In this study, we aimed to investigate the protective effects of PUR on type 2 diabetic nephropathy in vivo, in silico and in vitro, as well as unveil the underlying mechanism through inhibiting ferroptosis.

MATERIALS AND METHODS

In vivo, blood glucose and lipid, renal function, kidney histology and immunohistochemistry analysis were used to vindicate the protective effects of PUR on diabetic nephropathy in type 2 DN rat model. In silico, pharmacophore matching and enrichment analysis were adopted to predict the potential mechanism of PUR on DN. In vitro, we utilized high glucose stress to induce impairment in glomerular mesangial cells (GMCs) as diabetic nephropathy cell model. Cell count kit-8 (CCK-8) was used to observe cell viability. qPCR, Western blot, immunofluorescence staining and flow cytometry were used to evaluate the effect of PUR on the generation of extracellular matrix (ECM), ferroptosis and iron homeostasis in vitro and in vivo.

RESULTS

PUR markedly improved glucose and lipid metabolism, as well as alleviated renal dysfunction in diabetic nephropathy rats. Pharmacophore matching and enrichment analysis predicted the anti-DN effect of PUR may correlate with ECM. Experimental validation suggested that PUR treatment could inhibit the generation of ECM to alleviate high-glucose-induced cell impairments, suppressing ROS production and excessive collagen fiber accumulation in GMSs, and reduce mesangial matrix expansion and renal fibrosis in type 2 DN rats. Further study suggested that PUR protected GMCs against ferroptosis via reducing LDH release and GSH disruption, suppressing key regulators of two pathways for ferroptosis execution. Moreover, PUR also maintained iron metabolism hemostasis by regulating iron transportation proteins, iron exporter proteins, and iron storage proteins and reducing intracellular iron in type 2 DN rats.

CONCLUSION

PUR inhibited excessive ECM accumulation to protect against type 2 diabetic nephropathy, which meditated by regulating iron homeostasis and mitigating ferroptosis. This study provides promising therapeutics for diabetic nephropathy treatment.

Modified Shoutai Pill inhibited ferroptosis to alleviate recurrent pregnancy loss

ETHNOPHARMACOLOGICAL RELEVANCE

Modified Shoutai Pill, also called Jianwei Shoutai Pill (JSP), is a traditional Chinese medicine prescription that has been used as an effective agent for the treatment of miscarriage.

AIM OF THE STUDY

To explore the potential molecular mechanism of JSP against recurrent pregnancy loss (RPL).

MATERIALS AND METHODS

In vivo, CBA/J mated DBA/2 mice were used to conduct RPL model, while CBA/J mated BALB/c mice were seen as the control group. Mice were orally administered with JSP, Fer-1 (a ferroptosis inhibitor) or distilled water from day 0.5-12.5 of gestation (GD 0.5-12.5). Pregnancy outcomes were analyzed and ferroptosis related indexes of the whole implantation sites were measured on GD 12.5. In vitro, human trophoblast cell line HTR-8/SVneo was cultured and treated with RAS-selective lethal small molecule 3 (RSL3) (a ferroptosis agonist) or different concentrations of JSP. Then, ferroptosis related indexes were tested to analyze whether JSP could inhibit ferroptosis in HTR-8/SVneo cells.

RESULTS

In vivo consequences demonstrated that JSP or Fer-1 alleviated pregnancy outcomes including lower resorption rate and abortion rate. In addition, excessive iron accumulation and MDA level were inhibited, while GSH and GPX content were raised under JSP or Fer-1 exposure. Also, JSP or Fer-1 enhanced protein expressions of GPX4 and SLC7A11 which suppress ferroptosis, and lightened protein expression of ACSL4 which boosts ferroptosis. In vitro, JSP rescued HTR-8/SVneo cell death and migration ability that were injured by RSL3. Furthermore, JSP inhibited RSL3-induced intracellular reactive oxygen species (ROS), lipid ROS and iron deposition.

CONCLUSIONS

Collectively, our findings illustrated that the mechanism of JSP in treating RPL might be related to inhibiting ferroptosis, which provided a novel insight into the application of JSP in RPL intervention.

Inhibition of Apoc1 reverses resistance of sorafenib by promoting ferroptosis in esophageal cancers

Drug resistance is an obstacle in therapy of esophageal cancers (ECs), and the role of ferroptosis in progression ECs is still not clearly clarified. In the present study, we investigated the role of Apolipoprotein C1 (Apoc1) in regulating the sorafenib resistance in EC cells. Apoc1 was knock down after infection with Apoc1 shRNA lentivirus and stable cell lines for Apoc1 knockdown were screened. Cell viabilities were tested by MTT assay. ROS, MDA, and GSH tested by specific kits. In vivo experiment in nude mice were performed to test the correlation of Apoc1 and ferroptosis. The expression of Apoc1 and GPX4 was tested by western blotting. The results showed that Apoc1 was highly expressed in EC tissues and associated with poor overall survival rate of EC. Knockdown Apoc1 overcame resistance of sorafenib in EC cells and promoted erastin and sorafenib induced ferroptosis by upregulating the levels of ROS and MDA and downregulating the level of GSH in OE19/Sora and EC109/Sora cells. Rescue experiments proved that Apoc1 regulated sorafenib induced ferroptosis via GPX4. Furthermore, knockdown of Apoc1 inhibited the tumor progression by promoting ferroptosis in nude mice. In conclusion, knockdown Apoc1 overcome resistance of sorafenib in EC cells and in vivo by promoting sorafenib induced ferroptosis via GPX4. Targeting Apoc1 might be an effective way to reverse the drug resistance of sorafenib via inducing ferroptosis in EC progression.

Salvianolic acid A attenuates arsenic-induced ferroptosis and kidney injury via HIF-2α/DUOX1/GPX4 and iron homeostasis

Arsenic (As) is a prevalent pollutant in the environment and causes a high frequency of kidney disease in areas of high arsenic contamination, but its pathogenic mechanisms have yet to be completely clarified. Ferroptosis is a new form of cell death mainly dependent on lipid peroxidation and iron accumulation. Several reports have suggested that ferroptosis is operative in a spectrum of diseases caused by arsenic exposure, including in the lungs, pancreas, and testis. However, the mechanism and exact role of ferroptosis in arsenic-induced kidney injury is not known. Firstly, by constructing in vivo and in vitro arsenic exposure models, we confirmed the occurrence of ferroptosis based on the identification of the ability of NaASO2 to cause kidney injury. In addition, we found that arsenic exposure could upregulate DUOX1 expression in kidney and HK-2 cells, and after knocking down DUOX1 using siRNA was able to significantly upregulate GPX4 expression and attenuate ferroptosis. Subsequently using bioinformatics, we identified and proved the involvement of HIF-2α in the course of ferroptosis, and further confirmed by dual luciferase assay that HIF-2α promotes DUOX1 transcription to increase its expression. Finally, intervention with the natural ingredient SAA significantly attenuated arsenic-induced ferroptosis and kidney injury. These results showed that arsenic could cause ferroptosis and kidney injury by affecting HIF-2α/DUOX1/GPX4 and iron homeostasis and that SAA was an effective intervention component. This study not only discovered the molecular mechanism of sodium arsenite-induced kidney injury but also explored an active ingredient with intervention potential, providing a scientific basis for the prevention and treatment of sodium arsenite-induced kidney injury.