Molecular definitions of cell death subroutines: recommendations of the Nomenclature Committee on Cell Death 2012

Emerging Potential Therapeutic Targets of Ferroptosis in Skeletal Diseases

Ferroptosis is a new programmed cell death characterized by the accumulation of lipid peroxidation mediated by iron and inflammation. Since the transcentury realization of ferroptosis as an iron-dependent modality of nonapoptotic cell death in 2012, there has been growing interest in the function of ferroptosis and its relationship to clinical diseases. Recent studies have shown that ferroptosis is associated with multiple diseases, including degenerative diseases, ischemia reperfusion injury, cardiovascular disease, and cancer. Cell death induced by ferroptosis has also been related to several skeletal diseases, such as inflammatory arthritis, osteoporosis, and osteoarthritis. Research on ferroptosis can clarify the pathogenesis of skeletal diseases and provide a novel therapeutic target for its treatment. In this review, we summarize current information about the molecular mechanism of ferroptosis and describe its emerging role and therapeutic potential in skeletal diseases.

Mechanisms of Caspases 3/7/8/9 in the Degeneration of External Gills of Chinese Giant Salamanders (Andrias davidianus)

Metamorphosis is a critical stage in the adaptive development of amphibians from aquatic to terrestrial animals. Metamorphosis of the Chinese giant salamander is mainly manifested by the loss of external gills with consequent changes in the respiratory pattern. The loss of the external gill is regulated by the pathway of apoptosis in which caspase genes are the key factors. This study cloned and expressed the caspase 3/7/8/9 genes of the Chinese giant salamander. The main results were as follows: the complete open reading frames (ORFs) were 885 bp, 960 bp, 1461 bp and 1279 bp, respectively; caspase 3/7/8/9 genes all contained the CASc domain, and most of the motifs were located in CASc domain; and caspase 8 possessed two DED structural domains and caspase 9 possessed a CARD structural domain. Furthermore, results from the tissue distribution analysis indicated that caspase 3/7/8/9 genes were all significantly expressed in the external gill, and at 9 and 10 months of age (MOA), which is the peak time for the loss, the EXPRESSION level of caspase 3/7/8/9 genes was obviously high, which was consistent with the histological result. Moreover, the loss of external gills of the Chinese giant salamander may result from activation of both the apoptosis-related death receptor pathway and the mitochondrial pathway. Finally, it was discovered that thyroid hormone (TH) treatment could both advance the time point at which the external gills of the Chinese giant salamander began to degenerate and shorten this process. Interestingly, at the peak of its metamorphosis (9 MOA), the Chinese giant salamander further accelerated the metamorphosis rate of TH treatment, which suggested a promotive effect on the loss of external gills via the superimposition of the exogenous TH and caspase genes. The study of caspase genes in this experiment was conducive to understanding the mechanism of external gill loss in the Chinese giant salamander, as well as improving our understanding of the metamorphosis development of some Caudata species.

Necroptosis-Mediated eCIRP Release in Sepsis

Introduction

Extracellular cold-inducible RNA-binding protein (eCIRP) is an endogenous pro-inflammatory mediator that exacerbates injury in inflammation and sepsis. The mechanisms in which eCIRP is released have yet to be fully explored. Necroptosis is a programmed cell death that is dependent on the activation of mixed lineage kinase domain-like pseudo kinase (MLKL) which causes the release of damage-associated molecular patterns. We hypothesize that eCIRP is released through necroptosis and intensifies inflammation in sepsis.

Methods

RAW264.7 cells were treated with pan-caspase inhibitor z-VAD (15 μM) 1 h before stimulation with LPS (1 μg/mL). Necroptosis inhibitor, Necrostatin-1 (Nec-1) (10 μM) was added to the cells with LPS simultaneously. After 24 h of LPS stimulation, cytotoxicity was determined by LDH assay. eCIRP levels in the culture supernatants and phospho-MLKL (p-MLKL) from cell lysates were assessed by Western blot. p-MLKL interaction with the cell membrane was visualized by immunofluorescence. Sepsis was induced in C57BL/6 mice by cecal ligation and puncture (CLP). Mice were treated with Nec-1 (1 mg/kg) or DMSO. 20 h post-surgery, serum and peritoneal fluid levels of eCIRP, TNF-α and IL-6 were determined by ELISA. H&E staining of lung tissue sections was performed.

Results

We found that in RAW264.7 cells, LPS+z-VAD induces necroptosis as evidenced by an increase in p-MLKL levels and causes eCIRP release. Nec-1 reduces both p-MLKL activation and eCIRP release in LPS+z-VAD-treated RAW264.7 cells. Nec-1 also inhibits the release of eCIRP, TNF-α and IL-6 in the serum and peritoneal fluid in CLP-induced septic mice. We predicted a transient interaction between eCIRP and MLKL using a computational model, suggesting that eCIRP may exit the cell via the pores formed by p-MLKL.

Conclusion

Necroptosis is a novel mechanism of eCIRP release in sepsis. Targeting necroptosis may ameliorate inflammation and injury in sepsis by inhibiting eCIRP release.

Prenylation Defects and Oxidative Stress Trigger the Main Consequences of Neuroinflammation Linked to Mevalonate Pathway Deregulation

The cholesterol biosynthesis represents a crucial metabolic pathway for cellular homeostasis. The end products of this pathway are sterols, such as cholesterol, which are essential components of cell membranes, precursors of steroid hormones, bile acids, and other molecules such as ubiquinone. Furthermore, some intermediates of this metabolic system perform biological activity in specific cellular compartments, such as isoprenoid molecules that can modulate different signal proteins through the prenylation process. The defects of prenylation represent one of the main causes that promote the activation of inflammation. In particular, this mechanism, in association with oxidative stress, induces a dysfunction of the mitochondrial activity. The purpose of this review is to describe the pleiotropic role of prenylation in neuroinflammation and to highlight the consequence of the defects of prenylation.

Synthesis of Carvacrol Derivatives as Potential New Anticancer Agent against Lung Cancer

Lung cancer remains a major public health concern among all cancer diseases due to the toxicity and side-effects of the available commercially synthesized drugs. Natural product-derived synthesized anticancer drugs are now of promising interest to fight against cancer death. Carvacrol is a major component of most essential oil-bearing plants with potential pharmacological activity, especially against various cancer cell lines. Among the other organometallic compounds, copper complexes have been reported to be effective anticancer agents against various cancer cell lines, especially lung and leukemia cancers, due to the nontoxic nature of copper in normal cells since it is an endogenic metal. In this study, we synthesized three carvacrol derivatives, i.e., carvacrol aldehyde, Schiff base, and copper–Schiff base complex, through an established synthesis protocol and characterized the synthesized product using various spectroscopic techniques. The synthesized derivatives were evaluated for in vitro cytotoxic activity against different cancer cell lines, including human lung cancer (A549) and human fibroblast (BALB-3T3). Our findings showed that the copper–Schiff base complex derived from carvacrol inhibited the proliferation and migration of the A549 cell lines in a dose-dependent manner. This activity might be due to the inhibition of cell proliferation and migration at the G₂/M cell-cycle phase, as well as apoptosis, possibly through the activation of the mitochondrial apoptotic pathway. To our knowledge, this is the first report on the activity of the copper–Schiff base complex of carvacrol against A549 cell lines. Our result highlights that a new synthesized copper complex from carvacrol could be a novel potential drug in the treatment of lung cancer.

Mechanisms of cancer cell death induction by paclitaxel: an updated review

Chemoresistance of cancer cells is a major problem in treating cancer. Knowledge of how cancer cells may die or resist cancer drugs is critical to providing certain strategies to overcome tumour resistance to treatment. Paclitaxel is known as a chemotherapy drug that can suppress the proliferation of cancer cells by inducing cell cycle arrest and induction of mitotic catastrophe. However, today, it is well known that paclitaxel can induce multiple kinds of cell death in cancers. Besides the induction of mitotic catastrophe that occurs during mitosis, paclitaxel has been shown to induce the expression of several pro-apoptosis mediators. It also can modulate the activity of anti-apoptosis mediators. However, certain cell-killing mechanisms such as senescence and autophagy can increase resistance to paclitaxel. This review focuses on the mechanisms of cell death, including apoptosis, mitotic catastrophe, senescence, autophagic cell death, pyroptosis, etc., following paclitaxel treatment. In addition, mechanisms of resistance to cell death due to exposure to paclitaxel and the use of combinations to overcome drug resistance will be discussed.

Iron chelator deferasirox inhibits NF-κB activity in hepatoma cells and changes sorafenib-induced programmed cell deaths

OBJECTIVE

The improvements of antitumor effects and tolerability on chemotherapy for advanced hepatocellular carcinoma (HCC) are warranted. Here, we aimed to elucidate the mechanism of the combining effect of tyrosine kinase inhibitor sorafenib (SOR) and iron chelator deferasirox (DFX) in human hepatoma cell lines, HepG2 and Huh-7.

METHODS

The types of programmed cell deaths (PCDs); necrosis/necroptosis and apoptosis, were evaluated by flow cytometry and fluorescent microscopy. Human cleaved caspase-3 was analyzed by ELISA for apoptosis. GSH assay was used for ferroptosis. PCDs inhibition was analyzed by adding apoptosis inhibitor Z-VAD-FMK, ferroptosis inhibitor ferrostatin-1, necroptosis inhibitor necrosulfonamide, respectively. The expression of NF-κB was quantified by Western blotting.

RESULTS

In SOR monotherapy, cleaved caspase-3 expression was increased in all concentrations, confirming the result that SOR induces apoptosis. In SOR monotherapy, GSH/GSSG ratio was decreased on concentration-dependent, showing that SOR also induced ferroptosis. Lipid Peroxidation caused by SOR, corresponding to ferroptosis, was suppressed by DFX. In fluorescence microscopy of SOR monotherapy, apoptosis was observed at a constant rate on all concentrations, while necroptosis and ferroptosis were increased on high concentration. In sorafenib and deferasirox combinations, sub G1 phase increased additively. In SOR and DFX combinations, the cytotoxic effects were not suppressed by ferrostatin-1, but suppressed by Z-VAD-FMK and necrosulfonamide. In each monotherapy, and SOR + DFX combinations, the expression of NF-κB in nucleus was suppressed. Regarding PCD by SOR and DFX combination, ferroptosis was suppressed and both apoptosis and necroptosis became dominant.

CONCLUSION

Suppression of NF-κB is possibly involved in the effect of DFX. As a result, SOR and DFX combination showed additive antitumor effects for HCC through the mechanism of programed cell deaths and NF-kB signal modification.

Antitumor Effect of Guatteria olivacea R. E. Fr. (Annonaceae) Leaf Essential Oil in Liver Cancer

Guatteria olivacea R. E. Fries (synonym Guatteria punctata (Aubl.) R.A. Howard) is a tree of 10–27 m tall popularly known as “envira-bobó”, “envira-fofa”, “envireira”, “embira”, “embira-branca”, “embira-preta”, envira-branca”, and “envira-preta”, which can be found in the Brazilian Amazon biome. In this study, we evaluated the cytotoxic and antitumor effects of the essential oil (EO) obtained from the leaves of G. olivacea against liver cancer using HepG2 cells as a model. EO was obtained using a hydrodistillation Clevenger-type apparatus and was qualitatively and quantitatively characterized using GC–MS and GC–FID, respectively. The alamar blue assay was used to assess the cytotoxic potential of EO in a panel of human cancer cell lines and human non-cancerous cells. In HepG2 cells treated with EO, YO-PRO-1/propidium iodide staining, cell cycle distribution, and reactive oxygen species (ROS) were examined. In C.B-17 SCID mice with HepG2 cell xenografts, the efficacy of the EO (20 and 40 mg/kg) was tested in vivo. GC–MS and GC–FID analyses showed germacrene D (17.65%), 1-epi-cubenol (13.21%), caryophyllene oxide (12.03%), spathulenol (11.26%), (E)-caryophyllene (7.26%), bicyclogermacrene (5.87%), and δ-elemene (4.95%) as the major constituents of G. olivacea leaf EO. In vitro cytotoxicity of EO was observed, including anti-liver cancer action with an IC₅₀ value of 30.82 μg/mL for HepG2 cells. In HepG2 cells, EO treatment increased apoptotic cells and DNA fragmentation, without changes in ROS levels. Furthermore, the EO inhibited tumor mass in vivo by 32.8–57.9%. These findings suggest that G. olivacea leaf EO has anti-liver cancer potential.

Hepatocellular Carcinoma Intrinsic Cell Death Regulates Immune Response and Prognosis

Ablative and locoregional treatment options, such as radiofrequency, ethanol injection, microwave, and cryoablation, as well as irreversible electroporation, are effective therapies for early-stage hepatocellular carcinoma (HCC). Hepatocyte death caused by ablative procedures is known to increase the release of tumor-associated antigen, thus enhancing tumor immunogenicity. In addition, the heat ablative resection induces pyroptotic cell death accompanied by the release of several inflammatory factors and immune-related proteins, including damage-associated molecular patterns (DAMPs), heat shock proteins (HSPs), ficolin 3, ATP, and DNA/RNA, which potentiate the antitumoral immune response. Surgical approaches that enhance tumor necrosis and reduce hypoxia in the residual liver parenchyma have been shown to increase the disease-free survival rate by reducing the host's immunosuppressive response. Scalpel devices and targeted surgical approach combined with immune-modulating drugs are an interesting and promising area to maximize therapeutic outcomes after HCC ablation.

Predicting Prognosis and Distinguishing Cold and Hot Tumors in Bladder Urothelial Carcinoma Based on Necroptosis-Associated lncRNAs

Background

In reference to previous studies, necroptosis played an important role in cancer development. Our team decided to explore the potential prognostic values of long non-coding RNAs (lncRNAs) associated with necroptosis in bladder urothelial carcinoma (BLCA) and their relationship with the tumor microenvironment (TME) and the immunotherapeutic response for accurate dose.

Methods

To obtain the required data, bladder urothelial carcinoma transcriptome data were searched from Cancer Genome Atlas (TCGA) (https://portal.gdc.cancer.gov/). We used co-expression analysis, differential expression analysis, and univariate Cox regression to screen out prognostic lncRNAs associated with necroptosis in BLCA. Then the least absolute shrinkage and selection operator (LASSO) was conducted to construct the necroptosis-associated lncRNAs model. Based on this model, we also performed the Kaplan–Meier analysis and time-dependent receiver operating characteristics (ROC) to estimate the prognostic power of risk score. Multivariate and univariate Cox regression analysis were performed to build up a nomogram. Calibration curves, and time-dependent ROC were also conducted to evaluate nomogram. Principal component analysis (PCA) revealed a difference between high- and low-risk groups. In addition, we explored immune analysis, gene set enrichment analyses (GSEA), and evaluation of the half-maximal inhibitory concentration (IC50) in constructed model. Finally, the entire samples were divided into three clusters based on model of necroptosis-associated lncRNAs to further compare immunotherapy in cold and hot tumors.

Results

A model was built up based on necroptosis-associated lncRNAs. The model revealed good consistence between calibration plots and prognostic prediction. The area of 1-, 3-, and 5-year OS under the ROC curve (AUC) were 0.707, 0.679, and 0.675. Risk groups could be helpful for systemic therapy due to the markedly diverse IC50 between risk groups. To our delight, clusters could effectively identify cold and hot tumors, which would be beneficial to accurate mediation. Clusters 2 and 3 were considered the hot tumor, which was more sensitive to immunotherapeutic drugs.

Conclusions

The outcomes of our study suggested that necroptosis-associated lncRNAs could effectively predict patients with BLCA prognosis, which may be helpful for distinguishing the cold and hot tumors and improving individual treatment of BLCA.

LAMP3 inhibits autophagy and contributes to cell death by lysosomal membrane permeabilization

ABBREVIATIONS

A253-control: A253 control for LAMP3 stable overexpression; A253- LAMP3: A253 LAPM3 stable overexpression; CASP1: caspase 1; CASP3: caspase 3; CHX: cycloheximide; CTSB: cathepsin B; CTSD: cathepsin D; CQ: chloroquine; DCs: dendritic cells; ER: endoplasmic reticulum; LGALS3: galectin 3; HCV: hepatitis C virus; HSG-control: HSG control for LAMP3 stable overexpression; HSG-LAMP3: HSG LAMP3 stable overexpression; HSP: heat shock protein; HTLV-1: human T-lymphocyte leukemia virus-1; IXA: ixazomib; LAMP: lysosomal associated membrane protein; MHC: major histocompatibility complex; mAb: monoclonal antibody; OE: overexpression; pepA: pepstatin A; pAb: polyclonal antibody; pSS: primary Sjögren syndrome; qRT-PCR: quantitative real- time reverse transcriptase polymerase chain reaction; SLE: systemic lupus erythematosus; SS: Sjögren syndrome; UPR: unfolded protein response; V-ATPase: vacuolar-type proton- translocating ATPase; Y-VAD: Ac-YVAD-cmk; Z-DEVD; Z-DEVD-fmk; Z-VAD: Z-VAD- fmk.

The impact of sensory neuropathy and inflammation on epithelial wound healing in diabetic corneas

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes, with several underlying pathophysiological mechanisms, some of which are still uncertain. The cornea is an avascular tissue and sensitive to hyperglycemia, resulting in several diabetic corneal complications including delayed epithelial wound healing, recurrent erosions, neuropathy, loss of sensitivity, and tear film changes. The manifestation of DPN in the cornea is referred to as diabetic neurotrophic keratopathy (DNK). Recent studies have revealed that disturbed epithelial-neural-immune cell interactions are a major cause of DNK. The epithelium is supplied by a dense network of sensory nerve endings and dendritic cell processes, and it secretes growth/neurotrophic factors and cytokines to nourish these neighboring cells. In turn, sensory nerve endings release neuropeptides to suppress inflammation and promote epithelial wound healing, while resident immune cells provide neurotrophic and growth factors to support neuronal and epithelial cells, respectively. Diabetes greatly perturbs these interdependencies, resulting in suppressed epithelial proliferation, sensory neuropathy, and a decreased density of dendritic cells. Clinically, this results in a markedly delayed wound healing and impaired sensory nerve regeneration in response to insult and injury. Current treatments for DPN and DNK largely focus on managing the severe complications of the disease. Cell-based therapies hold promise for providing more effective treatment for diabetic keratopathy and corneal ulcers.

The PI3K/AKT signalling pathway in inflammation, cell death and glial scar formation after traumatic spinal cord injury: Mechanisms and therapeutic opportunities

Objects

Traumatic spinal cord injury (TSCI) causes neurological dysfunction below the injured segment of the spinal cord, which significantly impacts the quality of life in affected patients. The phosphoinositide 3kinase/serine‐threonine kinase (PI3K/AKT) signaling pathway offers a potential therapeutic target for the inhibition of secondary TSCI. This review summarizes updates concerning the role of the PI3K/AKT pathway in TSCI.

Materials and Methods

By searching articles related to the TSCI field and the PI3K/AKT signaling pathway, we summarized the mechanisms of secondary TSCI and the PI3K/AKT signaling pathway; we also discuss current and potential future treatment methods for TSCI based on the PI3K/AKT signaling pathway.

Results

Early apoptosis and autophagy after TSCI protect the body against injury; a prolonged inflammatory response leads to the accumulation of pro‐inflammatory factors and excessive apoptosis, as well as excessive autophagy in the surrounding normal nerve cells, thus aggravating TSCI in the subacute stage of secondary injury. Initial glial scar formation in the subacute phase is a protective mechanism for TSCI, which limits the spread of damage and inflammation. However, mature scar tissue in the chronic phase hinders axon regeneration and prevents the recovery of nerve function. Activation of PI3K/AKT signaling pathway can inhibit the inflammatory response and apoptosis in the subacute phase after secondary TSCI; inhibiting this pathway in the chronic phase can reduce the formation of glial scar.

Conclusion

The PI3K/AKT signaling pathway has an important role in the recovery of spinal cord function after secondary injury. Inducing the activation of PI3K/AKT signaling pathway in the subacute phase of secondary injury and inhibiting this pathway in the chronic phase may be one of the potential strategies for the treatment of TSCI.

Alzheimer's Disease Connected Genes in the Post-Ischemic Hippocampus and Temporal Cortex

It is considered that brain ischemia can be causative connected to Alzheimer’s disease. In the CA1 and CA3 regions of the hippocampus and temporal cortex, genes related to Alzheimer’s disease, such as the amyloid protein precursor (APP), β-secretase (BACE1), presenilin 1 (PSEN1) and 2 (PSEN2), are deregulated by ischemia. The pattern of change in the CA1 area of the hippocampus covers all genes tested, and the changes occur at all post-ischemic times. In contrast, the pattern of gene changes in the CA3 subfield is much less intense, does not occur at all post-ischemic times, and is delayed in time post-ischemia relative to the CA1 field. Conversely, the pattern of gene alterations in the temporal cortex appears immediately after ischemia, and does not occur at all post-ischemic times and does not affect all genes. Evidence therefore suggests that various forms of dysregulation of the APP, BACE1 and PSEN1 and PSEN2 genes are associated with individual neuronal cell responses in the CA1 and CA3 areas of the hippocampus and temporal cortex with reversible cerebral ischemia. Scientific data indicate that an ischemic episode of the brain is a trigger of amyloidogenic processes. From the information provided, it appears that post-ischemic brain injury additionally activates neuronal death in the hippocampus and temporal cortex in an amyloid-dependent manner.

Resveratrol improves estrus disorder induced by bisphenol A through attenuating oxidative stress, autophagy, and apoptosis

Bisphenol A (BPA), as a widely used plasticizer, is easily absorbed by animals and humans. It has certain toxic effects on various tissues, including liver, heart, kidney, testis, and ovary. The toxic effects of BPA on animal reproduction have aroused widespread concern, but its regulatory mechanism and antidote in female animals estrus cycle remain unclear. In this study, the results displayed that BPA destroyed the normal estrus cycle of mice through decreasing the levels of progesterone and estradiol. Furthermore, BPA significantly increased the levels of oxidative stress, autophagy, and apoptosis in ovaries and granulosa cells. Interestingly, we found that the natural antioxidant resveratrol rescued estrus disorder and impaired estradiol secretion, reduced the abnormal reactive oxygen species accumulation, autophagy, and apoptosis in BPA exposed ovarian tissues. Moreover, transmission electron microscopy showed that resveratrol reduced BPA-induced autophagic vesicles formation and flow cytometry showed that resveratrol inhibited the increase of apoptotic cells induced by BPA on granulosa cells. Therefore, the supplement of resveratrol could restore BPA-induced estrus disorder by protecting ovarian granulosa cells. Overall, resveratrol is a potential drug to alleviate BPA-induced estrous cycle disorders and ovarian damage.

All About (NK Cell-Mediated) Death in Two Acts and an Unexpected Encore: Initiation, Execution and Activation of Adaptive Immunity

NK cells are key mediators of immune cell-mediated cytotoxicity toward infected and transformed cells, being one of the main executors of cell death in the immune system. NK cells recognize target cells through an array of inhibitory and activating receptors for endogenous or exogenous pathogen-derived ligands, which together with adhesion molecules form a structure known as immunological synapse that regulates NK cell effector functions. The main and best characterized mechanisms involved in NK cell-mediated cytotoxicity are the granule exocytosis pathway (perforin/granzymes) and the expression of death ligands. These pathways are recognized as activators of different cell death programmes on the target cells leading to their destruction. However, most studies analyzing these pathways have used pure recombinant or native proteins instead of intact NK cells and, thus, extrapolation of the results to NK cell-mediated cell death might be difficult. Specially, since the activation of granule exocytosis and/or death ligands during NK cell-mediated elimination of target cells might be influenced by the stimulus received from target cells and other microenvironment components, which might affect the cell death pathways activated on target cells. Here we will review and discuss the available experimental evidence on how NK cells kill target cells, with a special focus on the different cell death modalities that have been found to be activated during NK cell-mediated cytotoxicity; including apoptosis and more inflammatory pathways like necroptosis and pyroptosis. In light of this new evidence, we will develop the new concept of cell death induced by NK cells as a new regulatory mechanism linking innate immune response with the activation of tumour adaptive T cell responses, which might be the initiating stimulus that trigger the cancer-immunity cycle. The use of the different cell death pathways and the modulation of the tumour cell molecular machinery regulating them might affect not only tumour cell elimination by NK cells but, in addition, the generation of T cell responses against the tumour that would contribute to efficient tumour elimination and generate cancer immune memory preventing potential recurrences.

Ferroptosis at the crossroads of tumor-host interactions, metastasis, and therapy response

Ferroptosis is a form of regulated cell death characterized by the accumulation of lipid peroxides in an iron-dependent manner. Ferroptotic cell death is modulated by many metabolic pathways, such as pathways governing the metabolism of sugars, lipids, amino acids, and iron, as well as mitochondrial activity and redox homeostasis. Tumor metastasis and therapy resistance are the main obstacles to curing cancers. Because tumor cells usually exhibit higher iron dependence than normal cells, they may be more susceptible to ferroptosis despite being resistant to other forms of cell death. Moreover, recent evidence has suggested that ferroptosis is involved in tumor-host interactions, modulates the tumor microenvironment, and serves as an anti-metastatic mechanism. Thus, inducing ferroptosis in tumor cells has the potential to improve cancer treatment. Here, we review ferroptosis-regulating mechanisms and the roles of ferroptosis in malignant progression, including the tumor-host interactions, metastasis, and cancer therapy response.

Blue Light Induces RPE Cell Necroptosis, Which Can Be Inhibited by Minocycline

Purpose:

Damage to and death of the retinal pigment epithelium (RPE) are closely related to retinal degeneration. Blue light is a high-energy light that causes RPE damage and triggers inflammatory responses. This study investigates whether blue light induces RPE necroptosis, explores pharmacologic therapy and specific mechanisms, and provides hints for research on retinal degeneration.

Methods

The human RPE cell line ARPE-19 was cultured and subjected to blue light insult in vitro. Annexin V/PI was used to evaluate RPE survival. Minocycline was applied to inhibit the death of RPE. Proteomic measurement was used to analyze protein expression. Inhibitors of necroptosis and apoptosis were applied to assess the death mode. Immunofluorescence of protein markers was detected to analyze the mechanism of cell death. Subcellular structural changes were detected by transmission electron microscopy. Reactive oxygen species (ROS) was tested by DCFH-DA. Mitochondrial membrane potential (Δψ_m) was detected by JC-1. BALB/c mice received bule light exposure, and RPE flatmounts were stained for verification in vivo.

Results

Blue light illumination induced RPE death, and minocycline significantly diminished RPE death. Proteomic measurement showed that minocycline effectively mitigated protein hydrolysis and protein synthesis disorders. Necroptosis inhibitors (Nec-1s, GSK-872) increased the survival of RPE cells, but apoptosis inhibitors (Z-VAD-FMK) did not. After blue light illumination, high-mobility group box-1 (HMGB1) was released from the nucleus, receptor-interacting protein kinase 3 (RIPK3) aggregated, and mixed-lineage kinase domain-like protein (MLKL) increased in the RPE. The application of minocycline alleviated the above phenomena. After blue light illumination, RPE cells exhibited necrotic characteristics accompanied by destruction of cell membranes and vacuole formation, but nuclear membranes remained intact. Minocycline improved the morphology of RPE. Blue light increased ROS and decreased Δψ_m of RPE, minocycline did not reduce ROS but kept Δψ_m stable. In vivo, HMGB1 release and RIPK3 aggregation appeared in the RPE of BALB/c mice after blue light illumination, and minocycline alleviated this effect.

Conclusions

Blue light exposure causes RPE necroptosis. Minocycline reduces the death of RPE by keeping Δψ_m stable, inhibiting necroptosis, and preventing HMGB1 release. These results provide new ideas for the pathogenesis and treatment of retinal degeneration.

Triclosan-induced neuroinflammation develops caspase-independent and TNF-α signaling pathway associated necroptosis in Neuro-2a cells

Triclosan (TCS) is widely used in cosmetics and healthcare industry as a broad-spectrum antibacterial agent. The lipophilic property and persistent nature of TCS has led to severe health issues. In the present study, we have evaluated the neuroinflammatory effect of TCS on mouse Neuro-2a cells. Initial investigation confirmed a dose-dependent loss in viability and morphology of cells in presence of TCS. The transcription and translation studies confirmed a downregulation in the expression of autophagy markers in Neuro-2a cells. The confocal microscopy study revealed that the abrogated autophagy in TCS-treated cells occurred due to loss in the autophagy flux and prevention in the lipidation of autophagosome bilayer. The fluorescence microscopy also confirmed a loss in the formation of autophagolysosomes in neuronal cells with increasing TCS concentrations. TCS treatment resulted in loss of mitochondrial integrity in cells as evidenced by a decrease in mitochondrial membrane potential in JC-1 staining. Further, the transcriptional and translational studies confirmed the activation of TNF-α signaling pathway in TCS-treated cells thus enhancing the expression of RIPK1, RIPK3 and MLKL proteins and their phosphorylated forms. TCS was also found to increase the tau protein pathogenesis in Neuro-2a cells, which alludes to the development of tau-associated neurodegeneration. Altogether, this study confirms the neuroinflammatory actions of TCS in Neuro-2a cells involving a TNF-α-induced MLKL-mediated signaling.

Molecular Mechanisms of Iron Mediated Programmed Cell Death and Its Roles in Eye Diseases

Ferroptosis, a newly identified, iron-dependent type of programmed cell death, is active in several diseases, such as heart disease, brain damage, and cancer. Its main characteristics commonly involve excess iron accumulation, elevated lipid peroxides and reactive oxygen species, and reduced levels of glutathione and glutathione peroxidase 4 levels. The effects of ferroptosis in eye diseases cannot be underestimated, with ferroptosis becoming a research target in ocular disorders and emerging evidence from a series of in vivo and in vitro researches into ferroptosis revealing its role in eye conditions. However, no report provides comprehensive information on the pathophysiology of ferroptosis in eye diseases and its possible treatments. In the current review, we present an up-to-date overview of ferroptosis biology and its involvement in the pathological processes of ocular diseases. Furthermore, we pose several outstanding questions and areas for future research in this topic. We deem ferroptosis-associated cell death a pivotal new field of scientific study in ocular diseases and consider it a new therapeutic target in the treatment of some eye disorders.

Bioassay-Guided Isolation of 2-[p-(2-Carboxyhydrazino)phenoxy]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol from Oroxylum indicum and the Investigation of Its Molecular Mechanism Action of Apoptosis Induction

The leaf crude extract of Oroxylum indicum (L.) Kurz induces genomic DNA fragmentation, comet formation, and the inhibition of cell proliferation in the prostate cancer cell line PC3, as assessed by agarose gel electrophoresis, comet assay and MTT assay, respectively. The bioactive compound was purified through bioassay-guided fractionation using preparative HPLC and MTT assay. The light brown and water-soluble compound was characterized using 1H and 13C nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR), and electrospray ionization (ESI) mass spectrometry. The compound was identified as a glycosylated hydroquinone derivative, 2-[p-(2-Carboxyhydrazino)phenoxy]-6-(hydroxymethyl) tetrahy-dro-2H-pyran-3,4,5-triol (molecular formula, C13H18N2O8; molecular mass = 330). The identified phytocompound has not been reported earlier elsewhere. Therefore, the common name of the novel anticancer phytocompound isolated from Oroxylum indicum in this current study is oroxyquinone. The half-maximal inhibitory concentration (IC₅₀) of oroxyquinone on PC3 cells was 58.9 µM (95% CI = 54.5 to 63.7 µM). Treatment of PC3 cells with oroxyquinone induced genomic DNA fragmentation and chromatin condensation, increased in the annexin-V positive cells, arrested the cell cycle at S phases, and inhibited the cell migration; as assessed by comet assay, DAPI staining, flow cytometry and a wound healing assay, respectively. On the investigation of the molecular mechanism of the induction of apoptosis, the results indicated that oroxyquinone induced caspase-3 and PARP independent apoptosis but through the p38 pathway and the localization of AIF into the nucleus. The present study identifies a novel anticancer molecule and provides scientific evidence supporting the therapeutic potency of Oroxylum indicum for ethnomedicinal uses.

Deciphering a Novel Necroptosis-Related miRNA Signature for Predicting the Prognosis of Clear Cell Renal Carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common histological and devastating subtype of renal cell carcinoma. Necroptosis is a form of programmed cell death that causes prominent inflammatory responses. miRNAs play a significant role in cancer progression through necroptosis. However, the prognostic value of necroptosis-related miRNAs remains ambiguous. In this study, 39 necroptosis-related miRNAs (NRMs) were extracted and 17 differentially expressed NRMs between normal and tumor samples were identified using data form The Cancer Genome Atlas (TCGA). After applying univariate Cox proportional hazard regression analysis and LASSO Cox regression model, six necroptosis-related miRNA signatures were identified in the training cohort and their expression levels were verified by qRT-PCR. Using the expression levels of these miRNAs, all patients were divided into the high- and low-risk groups. Patients in the high-risk group showed poor overall survival (P < 0.0001). Time-dependent ROC curves confirmed the good performance of our signature. The results were verified in the testing cohort and the entire TCGA cohort. Univariate and multivariate Cox regression models demonstrated that the risk score was an independent prognostic factor. Additionally, a predictive nomogram with good performance was constructed to enhance the implementation of the constructed signature in a clinical setting. We then employed miRBD, miRTarBase, and TargetScan to predict the target genes of six necroptosis-related miRNAs. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that 392 potential target genes were enriched in cell proliferation-related biological processes. Six miRNAs and 59 differentially expressed target genes were used to construct an miRNA–mRNA interaction network, and 11 hub genes were selected for survival and tumor infiltration analysis. Drug sensitivity analysis revealed potential drugs that may contribute to cancer management. Hence, necroptosis-related genes play an important role in cancer biology. We developed, for the first time, a necroptosis-related miRNA signature to predict ccRCC prognosis.

Immunomodulation by Gut Microbiome on Gastrointestinal Cancers: Focusing on Colorectal Cancer

Gastrointestinal cancer (GI) is a global health disease with a huge burden on a patient's physical and psychological aspects of life and on health care providers. It is associated with multiple disease related challenges which can alter the patient's quality of life and well-being. GI cancer development is influenced by multiple factors such as diet, infection, environment, and genetics. Although activating immune pathways and components during cancer is critical for the host's survival, cancerous cells can target those pathways to escape and survive. As the gut microbiome influences the development and function of the immune system, research is conducted to investigate the gut microbiome-immune interactions, the underlying mechanisms, and how they reduce the risk of GI cancer. This review addresses and summarizes the current knowledge on the major immune cells and gut microbiome interactions. Additionally, it highlights the underlying mechanisms of immune dysregulation caused by gut microbiota on four major cancerous pathways, inflammation, cellular proliferation, apoptosis, and metastasis. Overall, gut-immune interactions might be a key to understanding GI cancer development, but further research is needed for more detailed clarification.

Evolutionary Diversity and Function of Metacaspases in Plants: Similar to but Not Caspases

Caspase is a well-studied metazoan protease involved in programmed cell death and immunity in animals. Obviously, homologues of caspases with evolutionarily similar sequences and functions should exist in plants, and yet, they do not exist in plants. Plants contain structural homologues of caspases called metacaspases, which differ from animal caspases in a rather distinct way. Metacaspases, a family of cysteine proteases, play critical roles in programmed cell death during plant development and defense responses. Plant metacaspases are further subdivided into types I, II, and III. In the type I Arabidopsis MCs, AtMC1 and AtMC2 have similar structures, but antagonistically regulate hypersensitive response cell death upon immune receptor activation. This regulatory action is similar to caspase-1 inhibition by caspase-12 in animals. However, so far very little is known about the biological function of the other plant metacaspases. From the increased availability of genomic data, the number of metacaspases in the genomes of various plant species varies from 1 in green algae to 15 in Glycine max. It is implied that the functions of plant metacaspases will vary due to these diverse evolutions. This review is presented to comparatively analyze the evolution and function of plant metacaspases compared to caspases.

Targeting regulated cell death (RCD) with small-molecule compounds in triple-negative breast cancer: a revisited perspective from molecular mechanisms to targeted therapies

Triple-negative breast cancer (TNBC) is a subtype of human breast cancer with one of the worst prognoses, with no targeted therapeutic strategies currently available. Regulated cell death (RCD), also known as programmed cell death (PCD), has been widely reported to have numerous links to the progression and therapy of many types of human cancer. Of note, RCD can be divided into numerous different subroutines, including autophagy-dependent cell death, apoptosis, mitotic catastrophe, necroptosis, ferroptosis, pyroptosis and anoikis. More recently, targeting the subroutines of RCD with small-molecule compounds has been emerging as a promising therapeutic strategy, which has rapidly progressed in the treatment of TNBC. Therefore, in this review, we focus on summarizing the molecular mechanisms of the above-mentioned seven major RCD subroutines related to TNBC and the latest progress of small-molecule compounds targeting different RCD subroutines. Moreover, we further discuss the combined strategies of one drug (e.g., narciclasine) or more drugs (e.g., torin-1 combined with chloroquine) to achieve the therapeutic potential on TNBC by regulating RCD subroutines. More importantly, we demonstrate several small-molecule compounds (e.g., ONC201 and NCT03733119) by targeting the subroutines of RCD in TNBC clinical trials. Taken together, these findings will provide a clue on illuminating more actionable low-hanging-fruit druggable targets and candidate small-molecule drugs for potential RCD-related TNBC therapies.

Ferroptosis in Hepatocellular Carcinoma: Mechanisms, Drug Targets and Approaches to Clinical Translation

Ferroptosis, an iron and reactive oxygen species (ROS)-dependent non-apoptotic type of regulated cell death, is characterized by a massive iron overload and peroxidation of polyunsaturated fatty acids (PUFAs), which finally results in cell death. Recent studies suggest that ferroptosis can influence carcinogenesis negatively and therefore may be used as a novel anti-cancer strategy. Hepatocellular carcinoma (HCC) is a deadly malignancy with poor chances of survival and is the second leading cause of cancer deaths worldwide. Diagnosis at an already late stage and general resistance to current therapies may be responsible for the dismal outcome. As the liver acts as a key factor in iron metabolism, ferroptosis is shown to play an important role in HCC carcinogenesis and, more importantly, may hold the potential to eradicate HCC. In this review, we summarize the current knowledge we have of the role of ferroptosis in HCC and the application of ferroptosis as a therapy option and provide an overview of the potential translation of ferroptosis in the clinical practice of HCC.

Activated Nrf-2 Pathway by Vitamin E to Attenuate Testicular Injuries of Rats with Sub-chronic Cadmium Exposure

Cadmium (Cd), a heavy metal element, cumulates in the testis and can cause male reproductive toxicity. Although vitamin E (VE) as one of potential antioxidants protects the testis against toxicity of Cd, the underlying mechanism remained uncompleted clear. The aim of this study was to investigate whether the Nrf-2 pathway is involved with the protective effect of VE on testicular damages caused by sub-chronic Cd exposure. Thirty-two SD rats were divided into four groups and orally administrated with VE and/or Cd for 28 consecutive days: control group, VE group (100 mg VE/kg), Cd group (5 mg CdCl₂/kg), and VE + Cd group (100 mg VE/kg + 5 mg CdCl₂/kg). The results showed that 28-day exposure of Cd caused accumulation of Cd, histopathological lesions, and alternations of sperm parameters (elevated rate of abnormal sperm, decreased count of sperm, declined motility, and viability of sperm). Moreover, the rats exposed to Cd showed significant oxidative stress (increased contents of MDA and decreased levels or activities of T-AOC, GSH, CAT, SOD and GSH-Px) and inhibition of Nrf-2 signaling pathway (downregulation of Nrf-2, HO-1, NQO-1, GCLC, GCLM and GST) of the testes. In contrast, VE treatment significantly reduced the Cd accumulation, alleviated histopathological lesions and dysfunctions, activated Nrf-2 pathway, and attenuated the oxidative stress caused by Cd in the testes of rats. In conclusion, VE, through upregulating Nrf-2 pathway, could protect testis against oxidative damages induced by sub-chronic Cd exposure.

Mitochondria signaling pathways in allergic asthma

Mitochondria, as the powerhouse organelle of cells, are greatly involved in regulating cell signaling pathways, including those related to the innate and acquired immune systems, cellular differentiation, growth, death, apoptosis, and autophagy as well as hypoxic stress responses in various diseases. Asthma is a chronic complicated airway disease characterized by airway hyperresponsiveness, eosinophilic inflammation, mucus hypersecretion, and remodeling of airway. The asthma mortality and morbidity rates have increased worldwide, so understanding the molecular mechanisms underlying asthma progression is necessary for new anti-asthma drug development. The lung is an oxygen-rich organ, and mitochondria, by sensing and processing O2, contribute to the generation of ROS and activation of pro-inflammatory signaling pathways. Asthma pathophysiology has been tightly associated with mitochondrial dysfunction leading to reduced ATP synthase activity, increased oxidative stress, apoptosis induction, and abnormal calcium homeostasis. Defects of the mitochondrial play an essential role in the pro-remodeling mechanisms of lung fibrosis and airway cells' apoptosis. Identification of mitochondrial therapeutic targets can help repair mitochondrial biogenesis and dysfunction and reverse related pathological changes and lung structural remodeling in asthma. Therefore, we here overviewed the relationship between mitochondrial signaling pathways and asthma pathogenic mechanisms.

Insulin growth factor binding protein-3 enhances dental implant osseointegration against methylglyoxal-induced bone deterioration in a rat model

PURPOSE

The aim of this study was to determine the effect of insulin growth factor binding protein-3 (IGFBP-3) on the inhibition of glucose oxidative stress and promotion of bone formation near the implant site in a rat model of methylglyoxal (MGO)-induced bone loss.

METHODS

An in vitro study was performed in MC3T3 E1 cells treated with chitosan gold nanoparticles (Ch-GNPs) conjugated with IGFBP-3 cDNA followed by MGO. An in vivo study was conducted in a rat model induced by MGO administration after the insertion of a dental implant coated with IGFBP-3.

RESULTS

MGO treatment downregulated molecules involved in osteogenic differentiation and bone formation in MC3T3 E1 cells and influenced the bone mineral density and bone volume of the femur and alveolar bone. In contrast, IGFBP-3 inhibited oxidative stress and inflammation and enhanced osteogenesis in MGO-treated MC3T3 E1 cells. In addition, IGFBP-3 promoted bone formation by reducing inflammatory proteins in MGO-administered rats. The application of Ch-GNPs conjugated with IGFBP-3 as a coating of titanium implants enhanced osteogenesis and the osseointegration of dental implants.

CONCLUSIONS

This study demonstrated that IGFBP-3 could be applied as a therapeutic component in dental implants to promote the osseointegration of dental implants in patients with diabetes, which affects MGO levels.

Myeloperoxidase Deficiency Alters the Process of the Regulated Cell Death of Polymorphonuclear Neutrophils

Polymorphonuclear neutrophils (PMNs) play a key role in host defense. However, their massive accumulation at the site of inflammation can delay regenerative healing processes and can initiate pathological inflammatory processes. Thus, the efficient clearance of PMNs mediated by the induction of regulated cell death is a key process preventing the development of these pathological conditions. Myeloperoxidase (MPO), a highly abundant enzyme in PMN granules, primarily connected with PMN defense machinery, is suggested to play a role in PMN-regulated cell death. However, the contribution of MPO to the mechanisms of PMN cell death remains incompletely characterized. Herein, the process of the cell death of mouse PMNs induced by three different stimuli – phorbol 12-myristate 13-acetate (PMA), opsonized streptococcus (OST), and N-formyl-met-leu-phe (fMLP) – was investigated. MPO-deficient PMNs revealed a significantly decreased rate of cell death characterized by phosphatidylserine surface exposure and cell membrane permeabilization. An inhibitor of MPO activity, 4-aminobenzoic acid hydrazide, did not exhibit a significant effect on PMA-induced cell death compared to MPO deficiency. Interestingly, only the limited activation of markers related to apoptotic cell death was observed (e.g. caspase 8 activation, Bax expression) and they mostly did not correspond to phosphatidylserine surface exposure. Furthermore, a marker characterizing autophagy, cleavage of LC3 protein, as well as histone H3 citrullination and its surface expression was observed. Collectively, the data show the ability of MPO to modulate the life span of PMNs primarily through the potentiation of cell membrane permeabilization and phosphatidylserine surface exposure.

Involvement of Akt and the antiapoptotic protein Bcl-xL in the inhibition of apoptosis of dendritic cells by Leishmania mexicana

The intracellular parasite Leishmania mexicana inhibits camptothecin (CPT)-induced apoptosis of monocyte-derived dendritic cells (moDC) through the down-regulation of p38 and JNK phosphorylation, while the kinase Akt is maintained active for 24 hours. In addition, the infection of moDC with L. mexicana promastigotes increases the protein presence of the antiapoptotic protein Bcl-xL. In the present work we aimed to investigate the role of Akt in the inhibition of apoptosis of moDC by L. mexicana and in the modulation of the expression of the antiapoptotic proteins Bcl-2, Mcl-1, and Bcl-xL. moDC were infected with L. mexicana metacyclic promastigotes and treated with CPT, an Akt inhibitor, or both and the MOMP and protein presence of active caspase 3, Bcl-2, Mcl-1, and Bcl-xL were evaluated. Our results show that the specific inhibition of Akt reverts the apoptosis protective effect exerted by L. mexicana on moDC reflected by a reduction in MOMP, caspase 3 activation, and upregulation of Bcl-xL. Interestingly, we also found that the infection of moDC with L. mexicana promastigotes induces a decrease in Bcl-2 along with an isoform change of Mcl-1, this independently to Akt activity. We demonstrated that Akt is deeply involved in the inhibition of apoptosis of moDC by L. mexicana.

Fucoidan Alleviates Renal Fibrosis in Diabetic Kidney Disease via Inhibition of NLRP3 Inflammasome-Mediated Podocyte Pyroptosis

Background: Fucoidan (FPS) has been widely used to treat renal fibrosis (RF) in patients with diabetic kidney disease (DKD); however, the precise therapeutic mechanisms remain unclear. Recently, research focusing on inflammation-derived podocyte pyroptosis in DKD has attracted increasing attention. This phenomenon is mediated by the activation of the nucleotide-binding oligomerization domain (Nod)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, leading to RF during DKD progression. Therefore, we designed a series of experiments to investigate the ameliorative effects of FPS on RF in DKD and the mechanisms that are responsible for its effect on NLRP3 inflammasome-mediated podocyte pyroptosis in the diabetic kidney.

Methods: The modified DKD rat models were subjected to uninephrectomy, intraperitoneal injection of streptozotocin, and a high-fat diet. Following induction of renal injury, the animals received either FPS, rapamycin (RAP), or a vehicle for 4 weeks. For in vitro research, we exposed murine podocytes to high glucose and MCC950, an NLRP3 inflammasome inhibitor, with or without FPS or RAP. Changes in the parameters related to RF and inflammatory podocyte injury were analyzed in vivo. Changes in podocyte pyroptosis, NLRP3 inflammasome activation, and activation of the adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin complex 1 (mTORC1)/NLRP3 signaling axis involved in these changes were analyzed in vivo and in vitro.

Results: FPS and RAP ameliorated RF and inflammatory podocyte injury in the DKD model rats. Moreover, FPS and RAP attenuated podocyte pyroptosis, inhibited NLRP3 inflammasome activation, and regulated the AMPK/mTORC1/NLRP3 signaling axis in vivo and in vitro. Notably, our data showed that the regulative effects of FPS, both in vivo and in vitro, on the key signaling molecules, such as p-AMPK and p-raptor, in the AMPK/mTORC1/NLRP3 signaling axis were superior to those of RAP, but similar to those of metformin, an AMPK agonist, in vitro.

Conclusion: We confirmed that FPS, similar to RAP, can alleviate RF in DKD by inhibiting NLRP3 inflammasome-mediated podocyte pyroptosis via regulation of the AMPK/mTORC1/NLRP3 signaling axis in the diabetic kidney. Our findings provide an in-depth understanding of the pathogenesis of RF, which will aid in identifying precise targets that can be used for DKD treatment.

Positive Aspects of Oxidative Stress at Different Levels of the Human Body: A Review

Oxidative stress is the subject of numerous studies, most of them focusing on the negative effects exerted at both molecular and cellular levels, ignoring the possible benefits of free radicals. More and more people admit to having heard of the term "oxidative stress", but few of them understand the meaning of it. We summarized and analyzed the published literature data in order to emphasize the importance and adaptation mechanisms of basal oxidative stress. This review aims to provide an overview of the mechanisms underlying the positive effects of oxidative stress, highlighting these effects, as well as the risks for the population consuming higher doses than the recommended daily intake of antioxidants. The biological dose-response curve in oxidative stress is unpredictable as reactive species are clearly responsible for cellular degradation, whereas antioxidant therapies can alleviate senescence by maintaining redox balance; nevertheless, excessive doses of the latter can modify the redox balance of the cell, leading to a negative outcome. It can be stated that the presence of oxidative status or oxidative stress is a physiological condition with well-defined roles, yet these have been insufficiently researched and explored. The involvement of reactive oxygen species in the pathophysiology of some associated diseases is well-known and the involvement of antioxidant therapies in the processes of senescence, apoptosis, autophagy, and the maintenance of cellular homeostasis cannot be denied. All data in this review support the idea that oxidative stress is an undesirable phenomenon in high and long-term concentrations, but regular exposure is consistent with the hormetic theory.

Solamargine induces autophagy-mediated apoptosis and enhances bortezomib activity in multiple myeloma

Multiple myeloma (MM) is an incurable plasma cell malignancy with a poor survival rate. Conventional chemotherapeutic agent‐induced adverse events, including toxicity, neuropathy or drug resistance, significantly decrease the patients' quality of life and can even lead to interruption of treatment. Therefore, novel therapeutic drugs and strategies are urgently needed to improve MM therapy and patient outcomes. Here, we show that solamargine (SM), a steroidal alkaloid glycoside isolated from a Chinese herb Solanum nigrum L., exhibits promising anti‐MM activity. In particular, SM suppressed the viability of MM cell lines (ARP‐1 and NCI‐H929) in a concentration‐ and time‐dependent manner, inducing apoptosis in these cells. RNA‐seq analysis showed that treatment with SM led to the upregulation of genes associated with cell death and autophagy in H929 cells. Further, we found that treatment with SM activated autophagy in the MM cells, as incubation with 3‐Methyladenine, an inhibitor of autophagy, significantly alleviated SM‐triggered apoptosis and inhibition of viability in MM cells. Interestingly, we also observed a synergistic effect between SM and bortezomib (BTZ), a common chemotherapeutic agent for MM, in both MM cells and human bone marrow CD138+ primary myeloma cells. We also confirmed the single‐agent efficacy of SM and the synergistic effects between SM and BTZ in an MM xenograft mouse model. Collectively, these findings indicate that SM exerts an anti‐MM effect, at least in part, by activating cell autophagy and reveal that SM alone or in combination with BTZ is a potential therapeutic strategy for treating MM.

A multi-omics-based investigation of the immunological and prognostic impact of necroptosis-related genes in patients with hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is the most common histological subtype of liver cancer and the third leading cause of death from cancer globally. Recent studies suggested cell death is also a key regulator of tumour progression. The purpose of this study was to generate a new predictive signature for HCC patients based on a complete analysis of necroptosis‐associated genes.

Methods

We extracted the mRNA expression profiles of HCC patients from the TCGA and ICGC databases and their clinical data. In addition, we used the IMvigor210 cohort to validate our model molecule's ability to predict the effect of immunotherapy. In the TCGA cohort, a seven‐gene risk‐prognostic model was constructed using univariate cox‐Lasoo regression. External validation was conducted using the ICGC cohort. The ssGSEA algorithm is used to determine the degree of immune function response. The CMAP databases are used for chemotherapy drug analysis and screening for drugs that reduce the expression of high‐risk genes. The cbioportal database was used to explore mutations in model genes.

Results

Survival analysis shows shorter survival for high‐risk patients. Immune function analysis revealed significant differences in the activity of immune pathways between risk subgroups. Varied risk scores result in dramatically diverse immune infiltration and tumour growth, as well as significantly different chemotherapeutic sensitivity. In addition, Apigenin and LY‐294002 reduced the expression of high‐risk genes, while Arecoline had the opposite effect. In the immunotherapy IMvigor210 cohort, risk scores were significantly different between the objective responder and non‐responder groups. By comparing the models constructed with published literature, it is suggested that our model has better predictive power.

Conclusions

We created a new prognostic signature of necroptosis‐related genes that can be used as potential prognostic biomarkers to guide effective personalized therapy for hepatocellular carcinoma patients.

Inhibition of Myocardial Cell Apoptosis Is Important Mechanism for Ginsenoside in the Limitation of Myocardial Ischemia/Reperfusion Injury

Ischemic heart disease has a high mortality, and the recommended therapy is reperfusion. Nevertheless, the restoration of blood flow to ischemic tissue leads to further damage, namely, myocardial ischemia/reperfusion injury (MIRI). Apoptosis is an essential pathogenic factor in MIRI, and ginsenosides are effective in inhibiting apoptosis and alleviating MIRI. Here, we reviewed published studies on the anti-apoptotic effects of ginsenosides and their mechanisms of action in improving MIRI. Each ginsenoside can regulate multiple pathways to protect the myocardium. Overall, the involved apoptotic pathways include the death receptor signaling pathway, mitochondria signaling pathway, PI3K/Akt signaling pathway, NF-κB signaling pathway, and MAPK signaling pathway. Ginsenosides, with diverse chemical structures, regulate different apoptotic pathways to relieve MIRI. Summarizing the effects and mechanisms of ginsenosides contributes to further mechanism research studies and structure-function relationship research studies, which can help the development of new drugs. Therefore, we expect that this review will highlight the importance of ginsenosides in improving MIRI via anti-apoptosis and provide references and suggestions for further research in this field.

The role of RIPK3 in liver mitochondria bioenergetics and function

BACKGROUND

Receptor-interacting protein kinase 3 (RIPK3) is a key player of regulated necrosis or necroptosis, an inflammatory form of cell death possibly governing outcomes in chronic liver diseases, such as nonalcoholic fatty liver disease and nonalcoholic steatohepatitis.

METHODS

This narrative review is based on literature search using PubMed.

RESULTS

RIPK3 activation depends on post-transcriptional modifications, including phosphorylation, hence coordinating the assembly of macromolecular death complex named 'necrosome', which may also involve diverse mitochondrial components. Curiously, recent studies suggested a potential link between RIPK3 and mitochondrial bioenergetics. RIPK3 can modulate mitochondrial function and quality through the regulation of mitochondrial reactive oxygen species production, sequestration of metabolic enzymes and resident mitochondrial proteins, activity of mitochondrial respiratory chain complexes, mitochondrial biogenesis and fatty acid oxidation.

CONCLUSIONS

Since mitochondrial dysfunction and RIPK3-mediated necroptosis are intimately involved in chronic liver disease pathogenesis, understanding the role of RIPK3 in mitochondrial bioenergetics and its potential translational application are of great interest.

Ultrasound Protects Human Chondrocytes from Biochemical and Ultrastructural Changes Induced by Oxidative Stress

The aim of the study was to assess the effects of therapeutic ultrasound (US) on oxidative stress (OS)-induced changes in cultured human chondrocytes (HCH). For this, monolayer HCH were randomized in three groups: a control group (CG), a group exposed to OS (OS group), and a group exposed to US and OS (US-OS group). US exposure of the chondrocytes was performed prior to OS induction by hydrogen peroxide. Transmission electron microscopy (TEM) was used to assess the chondrocytes ultrastructure. OS and inflammatory markers were recorded. Malondialdehyde (MDA) and tumor necrosis factor (TNF)-α were significantly higher (p < 0.05) in the OS group than in CG. In the US-OS group MDA and TNF-α were significantly lower (p < 0.05) than in the OS group. Finally, in the US-OS group MDA and TNF-α were lower than in CG, but without statistical significance. TEM showed normal chondrocytes in CG. In the OS group TEM showed necrotic chondrocytes and chondrocytes with a high degree of vacuolation and cell organelles damages. In the US-OS group the chondrocytes ultrastructure was well preserved, and autophagosomes were generated. In conclusion, US could protect chondrocytes from biochemical (lipid peroxidation, inflammatory markers synthesis) and ultrastructural changes induced by OS and could stimulate autophagosomes development.

[Autophagy modulation by viruses: An important role in tumor progression]

Autophagy is an important process for cellular homeostasis at critical steps of development or in response to environmental stress. In the context of cancers, autophagy has a significant impact on tumor occurrence and tumor cell growth. On the one hand, autophagy limits the transformation of precancerous cells into cancer cells at an early stage. However, on the other hand, it promotes cell survival, cell proliferation, metastasis and resistance to anti-tumor therapies in more advanced tumors. Autophagy can be induced by a variety of extracellular and intracellular stimulus. Viral infections have often been associated with a modulation of autophagy, with variable impacts on viral replication and on the survival of infected cells depending on the model studied. In a tumor context, the modulation of autophagy induced by the viral infection of tumor cells seems to have a significant impact on tumor progression. The aim of this review article is to present recent findings regarding the consequences of autophagy disturbance by viral infections on tumor behavior.

Cell cycle involvement in cancer therapy; WEE1 kinase, a potential target as therapeutic strategy

Mitosis is the process of cell division and is regulated by checkpoints in the cell cycle. G1-S, S, and G2-M are the three main checkpoints that prevent initiation of the next phase of the cell cycle phase until previous phase has completed. DNA damage leads to activation of the G2-M checkpoint, which can trigger a downstream DNA damage response (DDR) pathway to induce cell cycle arrest while the damage is repaired. If the DNA damage cannot be repaired, the replication stress response (RSR) pathway finally leads to cell death by apoptosis, in this case called mitotic catastrophe. Many cancer treatments (chemotherapy and radiotherapy) cause DNA damages based on SSBs (single strand breaks) or DSBs (double strand breaks), which cause cell death through mitotic catastrophe. However, damaged cells can activate WEE1 kinase (as a part of the DDR and RSR pathways), which prevents apoptosis and cell death by inducing cell cycle arrest at G2 phase. Therefore, inhibition of WEE1 kinase could sensitize cancer cells to chemotherapeutic drugs. This review focuses on the role of WEE1 kinase (as a biological macromolecule which has a molecular mass of 96 kDa) in the cell cycle, and its interactions with other regulatory pathways. In addition, we discuss the potential of WEE1 inhibition as a new therapeutic approach in the treatment of various cancers, such as melanoma, breast cancer, pancreatic cancer, cervical cancer, etc.

Development and Validation of a Necroptosis-Related Prognostic Model in Head and Neck Squamous Cell Carcinoma

Necroptosis is a new regulated cell-death mechanism that plays a critical role in various cancers. However, few studies have considered necroptosis-related genes (NRGs) as prognostic indexes for cancer. As one of the most common cancers in the world, head and neck squamous cell carcinoma (HNSCC) lacks effective diagnostic strategies at present. Hence, a series of novel prognostic indexes are required to support clinical diagnosis. Recently, many studies have confirmed that necroptosis was a key regulated mechanism in HNSCC, but no systematic study has ever studied the correlation between necroptosis-related signatures and the prognosis of HNSCC. Thus, in the current study, we aimed to construct a risk model of necroptosis-related signatures for HNSCC. We acquired 159 NRGs from the Kyoto Encyclopedia of Genes and Genomes (KEGG) and compared them with samples of normal tissue downloaded from The Cancer Genome Atlas (TCGA), ultimately screening 38 differentially expressed NRGs (DE-NRGs). Then, by Cox regression analysis, we successfully identified 7 NRGs as prognostic factors. We next separated patients into high- and low-risk groups via the prognostic model consisting of 7 NRGs. Individuals in the high-risk group had much shorter overall survival (OS) times than their counterparts. Furthermore, using Cox regression analysis, we confirmed the necroptosis-related prognostic model to be an independent prognostic factor for HNSCC. Receiver operating characteristic (ROC) curve analysis proved the predictive ability of this model. Finally, Gene Expression Omnibus (GEO) data sets (GSE65858, GSE4163) were used as independent databases to verify the model’s predictive ability, and similar results obtained from two data sets confirmed our conclusion. Collectively, in this study, we first referred to necroptosis-related signatures as an independent prognostic model for cancer via bioinformatics measures, and the necroptosis-related prognostic model we constructed could precisely forecast the OS time of patients with HNSCC. Utilizing the model may significantly improve the diagnostic rate and provide a series of new targets for treatment in the future.

Autophagy Promotes α-Amanitin-Induced Apoptosis of Hepa1-6 Liver Cells

It is estimated that 90% of deaths from food poisoning in China can be attributed to Amanita poisoning, whose main toxin is α-amanitin. Studies showed that apoptosis plays a critical role in liver injuries induced by α-amanitin. Although the relationship between autophagy and apoptosis in different liver models has been addressed many times, whether autophagy plays a pro or con effect on α-amanitin-induced apoptosis has not been clarified. Therefore, this study was conducted to explore the effect of autophagy in α-amanitin-induced apoptosis in Hepa1-6 liver cells. A 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay was applied to determine cell viability, a 2',7'-dichlorofluorescin diacetate probe was used to monitor reactive oxygen species (ROS) levels, a flow cytometer and dansylcadaverine (MDC) staining were used to observe α-amanitin-induced apoptosis and autophagy, respectively, and apoptosis and autophagy proteins were assessed by western blotting. The results showed that α-amanitin suppressed cell viability in a time- and concentration-dependent manner. Moreover, the release of ROS was increased with increasing α-amanitin amount. Cell apoptosis and autophagy were noticed and characterized by the increased apoptosis rate and autophagic vesicles under a fluorescence microscope as well as upregulation of Bax/Bcl-2, cleaved caspase-3, and LC3-II/I and downregulation of p62. Further, the autophagy activator rapamycin (Rap) and the inhibitor 3-methylademine (3-MA) were introduced, which showed that the apoptosis rate and the ratio of Bax/Bcl-2 as well as the protein expression level of cleaved caspase-3 increased significantly with the pretreatment of Rap and decreased remarkably with the pretreatment of 3-MA. Moreover, cell viability was found to decrease further with the promotion of autophagy. Notably, the ROS level was attenuated after autophagy was elevated. In conclusion, autophagy could promote α-amanitin-induced Hepa1-6 cell apoptosis, and the process is unassociated with ROS levels. This research provides a theoretical basis for the study of the toxicological mechanism of α-amanitin-induced liver injuries.

Targeting the DNA Damage Response for Cancer Therapy by Inhibiting the Kinase Wee1

Cancer cells typically heavily rely on the G2/M checkpoint to survive endogenous and exogenous DNA damage, such as genotoxic stress due to genome instability or radiation and chemotherapy. The key regulator of the G2/M checkpoint, the cyclin-dependent kinase 1 (CDK1), is tightly controlled, including by its phosphorylation state. This posttranslational modification, which is determined by the opposing activities of the phosphatase cdc25 and the kinase Wee1, allows for a more rapid response to cellular stress than via the synthesis or degradation of modulatory interacting proteins, such as p21 or cyclin B. Reducing Wee1 activity results in ectopic activation of CDK1 activity and drives premature entry into mitosis with unrepaired or under-replicated DNA and causing mitotic catastrophe. Here, we review efforts to use small molecule inhibitors of Wee1 for therapeutic purposes, including strategies to combine Wee1 inhibition with genotoxic agents, such as radiation therapy or drugs inducing replication stress, or inhibitors of pathways that show synthetic lethality with Wee1. Furthermore, it become increasingly clear that Wee1 inhibition can also modulate therapeutic immune responses. We will discuss the mechanisms underlying combination treatments identifying both cell intrinsic and systemic anti-tumor activities.

GSK-3β-mediated activation of NLRP3 inflammasome leads to pyroptosis and apoptosis of rat cardiomyocytes and fibroblasts

We previously demonstrated that GSK-3β mediates NLRP3 inflammasome activation and IL-1β production in cardiac fibroblasts (CFs) after myocardial infarction (MI). In this study, we show how GSK-3β-mediated activation of the NLRP3 inflammasome/caspase-1/IL-1β pathway leads to apoptosis and pyroptosis of cardiomyocytes (CMs) and CFs. Administration of lipopolysaccharide (LPS)/ATP to primary newborn rat cardiac fibroblasts (RCFs) led to increase in proteins of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, IL-1β, and IL-18. Additionally, the expression of caspase-3 and N-terminal fragments of gasdermin D (N-GSDMD) and the Bax/Bcl-2 ratio increased. Administration of the GSK-3β inhibitor SB216763 reduced the levels of apoptosis- and pyroptosis-related proteins regulated by NLRP3 inflammasome activation in RCFs. Next, we transferred the culture supernatant of LPS/ATP-treated RCFs to in vitro primary newborn rat cardiomyocytes (RCMs). The results showed that SB216763 attenuate the upregulation of the ratios of Bax/Bcl-2 and the expression of caspase-3 and N-GSDMD in RCMs. Direct stimulation of RCMs and H9c2 cells with recombinant rat IL-1β increased the p-GSK-3β/GSK-3β and Bax/Bcl-2 ratios and the expression of caspase-3 and N-GSDMD, while both SB216763 and TLR1 (an IL-1β receptor inhibitor) markedly reduced these effects, as assessed using propidium iodide positive staining and the lactate dehydrogenase release assay. The caspase-11 inhibitor wedelolactone decreased the expression level of N-GSDMD but did not alter the p-GSK-3β/GSK-3β ratio. Lastly, we established a Sprague-Dawley rat MI model to confirm that SB216763 diminished the increase in caspase-3 and N-GSDMD expression and the Bax/Bcl-2 ratio in the ischemic area. These data demonstrate that GSK-3β regulates apoptosis and pyroptosis of RCMs and RCFs due to NLRP3 inflammasome activation in RCFs.

Identification and Quantification of Necroptosis Landscape on Therapy and Prognosis in Kidney Renal Clear Cell Carcinoma

Kidney renal clear cell carcinoma (KIRC) has high morbidity and gradually increased in recent years, and the rate of progression once relapsed is high. At present, owing to lack of effective prognosis predicted markers and post-recurrence drug selection guidelines, the prognosis of KIRC patients is greatly affected. Necroptosis is a regulated form of cell necrosis in a way that is independent of caspase. Induced necroptosis is considered an effective strategy in chemotherapy and targeted drugs, and it can also be used to improve the efficacy of immunotherapy. Herein, we quantified the necroptosis landscape of KIRC patients from The Cancer Genome Atlas (TCGA) database and divided them into two distinct necroptosis-related patterns (C1 and C2) through the non-negative matrix factorization (NMF) algorithm. Multi-analysis revealed the differences in clinicopathological characteristics and tumor immune microenvironment (TIME). Then, we constructed the NRG prognosis signature (NRGscore), which contained 10 NRGs (PLK1, APP, TNFRSF21, CXCL8, MYCN, TNFRSF1A, TRAF2, HSP90AA1, STUB1, and FLT3). We confirmed that NRGscore could be used as an independent prognostic marker for KIRC patients and performed excellent stability and accuracy. A nomogram model was also established to provide a more beneficial prognostic indicator for the clinic. We found that NRGscore was significantly correlated with clinicopathological characteristics, TIME, and tumor mutation burden (TMB) of KIRC patients. Moreover, NRGscore had effective guiding significance for immunotherapy, chemotherapy, and targeted drugs.

Zhilong Huoxue Tongyu Capsule Alleviated the Pyroptosis of Vascular Endothelial Cells Induced by ox-LDL through miR-30b-5p/NLRP3

Background

Our previous studies have demonstrated a protective role of Zhilong Huoxue Tongyu capsule in atherosclerosis (AS); however, the molecular mechanisms are unclear.

Methods

Human coronary artery endothelial cells (HCAECs) were induced with oxidized low-density lipoprotein (ox-LDL) to obtain cellular AS models. Then, the medicated serum of Zhilong Huoxue Tongyu capsule was obtained and used for treatment with ox-LDL-induced HCAECs. The cell viability was detected by CCK-8 assay. Besides, the binding between miR-30b-5p and NLRP3 was determined by the dual-luciferase reporter gene system assay. Furthermore, ox-LDL-induced HCAECs were transfected with miR-30b-5p mimic or miR-30b-5p inhibitor. The pyroptosis of HCAECs was assessed by flow cytometry, LDH content detection, and qRT-PCR assays.

Results

10% medicated serum of Zhilong Huoxue Tongyu capsule was the maximum nontoxic concentration and it was used in subsequent assays. The rate of pyroptosis, LDH content, and the mRNA expression level of pyroptosis-related genes including NLRP3, ASC, Caspase 1, IL-1β, and IL-18 were prominently enhanced after HCAECs were induced by ox-LDL, which were markedly rescued with medicated serum of Zhilong Huoxue Tongyu capsule. In addition, the medicated serum of Zhilong Huoxue Tongyu capsule significantly enhanced the ox-LDL-induced reduction of miR-30b-5p level. NLRP3 could bind to miR-30b-5p and was negatively corrected with miR-30b-5p. Moreover, all the rates of pyroptosis, LDH content, and the mRNA expression levels of pyroptosis-related genes including NLRP3, ASC, Caspase 1, IL-1β, and IL-18 were further observably decreased after ox-LDL-induced HCAECs treated with medicated serum were transfected with miR-30b-5p mimic, while these were significantly rescued with transfection of miR-30b-5p inhibitor.

Conclusion

Zhilong Huoxue Tongyu capsule alleviated the pyroptosis of vascular endothelial cells induced by ox-LDL through miR-30b-5p/NLRP3.

Programmed cell death and liver diseases

Cell death represents the most critical pathologic entity in liver disease, which dictates pathologic consequences such as inflammation, fibrosis, and cell transformation. We analyzed the conclusions of studies on the involvement of different types of programmed cell death (PCD) in the pathogenesis of liver diseases. Three main forms of PCD (autophagy, apoptosis, necrosis) and five additional, still insufficiently studied PCD – necroptosis, ferroptosis, pyroptosis, partanatosis and entosis – observed in the liver in various acute and chronic diseases are considered. The involvement of several PCD at once in the development of any one pathology and one type of PCD in different pathologies was established. This indicates the existence of cross-regulation of metabolism in the liver cells with different levels of damage in the formation of the main dominant type of PCD. Available results indicate the possibility of attenuation (correction) of functional and morphological manifestations of PCD in the organ by controlled blocking of effector-mediated PCD pathways, as well as targeted induction of autophagy, anti-apoptotic and anti-necrotic mechanisms in liver cells.

Hydroxysafflor yellow A and anhydrosafflor yellow B alleviate ferroptosis and parthanatos in PC12 cells injured by OGD/R

Ferroptosis and parthanatos are two types of programmed cell death associated with cerebral ischemia. There is a sizeable interest in seeking chemical components for the regulation of ferroptosis and parthanatos. Hydroxysafflor yellow A (HSYA) and anhydrosafflor yellow B (AHSYB) mitigated cell death caused by oxidative stress due to antioxidant capacity, yet the mechanism is still uncertain. Thus, we investigated whether HSYA and AHSYB prevent death through these two pathways with the aim to elucidate their potential protective mechanisms of cerebral ischemia. In this study, oxidative stress model was established by treating PC12 cells with oxygen glucose deprivation and reperfusion (OGD/R). Cellular functions and signaling pathways were analyzed in PC12 cells using cell counting kit-8 (CCK-8), flow cytometry, ELISA, iron assay kit, transmission electron microscopy (TEM), immunofluorescence, and western blot analysis. And the research proved HSYA and AHSYB protected cells from oxidative stress. The phenomenon is associated with ferroptosis and parthanatos. HSYA and AHSYB upregulated cystine/glutamate antiporter system x_c^- (system x_c^-) and glutathione peroxidase 4 (GPX4), returned the levels of GSH/GSSG ratio, reactive oxygen species (ROS) and iron ion, as well as alleviated lipid peroxidation. By reason of reducing ROS, HSYA and AHSYB restrained poly(ADP-ribose) polymerase-1 (PARP-1) overactivation, reduced the production of excess poly(ADP-ribose) (PAR) polymer and apoptosis inducing factor (AIF) nuclear translocation. The results suggested that HSYA and AHSYB limited ferroptosis and parthanatos to alleviate oxidative stress in PC12 cells. These findings may have implications for improving understanding of how drugs reduce oxidative stress and develop new strategies for treating degenerative diseases such as cerebral ischemia.