Apoptosis in the pathogenesis and treatment of disease

The complexities of cell death mechanisms: a new perspective in systemic sclerosis therapy

Systemic sclerosis, also termed scleroderma, is a severe and debilitating autoimmune disease characterized by fibrosis, an aberrant immune response, and vascular dysfunction. Cell death is essential to the body's continued normal development as it removes old or damaged cells. This process is governed by several mechanisms, including programmed cell death through apoptosis, necrosis, and pyroptosis, as well as metabolic processes, such as ferroptosis and cuproptosis. This review describes the signaling pathways associated with each form of cell death, examining the linkages between these pathways, and discussing how the dysregulation of cell death processes is involved in the development of autoimmune disorders such as systemic sclerosis. Existing and promising therapeutic strategies aimed at restoring the balance of cell death in systemic sclerosis and other autoimmune disorders are also emphasized.

The relationship of miR-155 host gene polymorphism in the susceptibility of cancer: a systematic review and meta-analysis

Background

miR-155 is overexpressed in many cancers, highlighting its potential as a biomarker for cancer diagnosis, treatment, and therapeutic evaluation. miR-155 is processed from the miR-155 host gene (MIR155HG). Genetic variations in MIR155HG may influence cancer susceptibility, but existing evidence is inconclusive. This study aimed to evaluate the association of MIR155HG polymorphisms with cancer risk.

Material/Methods

A systematic literature search identified 15 case-control studies on three single nucleotide polymorphisms (SNPs): rs767649 (T > A), rs928883 (G > A), and rs1893650 (T > C). Meta-analysis was performed using RevMan 5.4, with odds ratios (ORs) and 95% confidence intervals (CIs) as effect measures.

Results

No significant association was observed for rs767649 and rs928883 in overall cancer analysis. However, subgroup analysis revealed rs767649 increased susceptibility to respiratory, digestive, and reproductive cancers, while reducing cancer risk after excluding reproductive cancers. rs928883 showed a protective effect for digestive cancers. rs1893650 was not significantly associated with cancer risk.

Conclusion

MIR155HG polymorphisms influence susceptibility to specific cancer subtypes, particularly respiratory and digestive cancers. These findings underscore the importance of genetic and environmental factors in cancer risk and warrant further investigation.

Chinese Herbal Medicine and Their Active Ingredients Involved in the Treatment of Atopic Dermatitis Related Signaling Pathways

Atopic dermatitis (AD) is a common inflammatory dermatitis of the skin and poses therapeutic challenges due to the adverse reactions and high costs associated with available treatments. In Eastern Asian countries, a plethora of herbal remedies is extensively employed for the alleviation of AD. Many of these botanicals are renowned for their formidable anti-inflammatory properties, contributing to AD management. Chinese herbal medicine (CHM) and its active ingredients exhibit both prophylactic and therapeutic promise against AD by modulating inflammatory response, orchestrating immune system functions, and enhancing antioxidant activities. A comprehensive exploration of the underlying mechanisms involved in CHM treatment can enhance the comprehension of AD pathogenesis and facilitate the development of innovative drugs for AD. This study aims to elucidate the signaling pathways and potential targets implicated in CHM-based treatment of AD, providing a systematic theoretical framework for its application in therapy while serving as a valuable reference for developing more effective and safer AD therapeutic agents.

Crosstalk between non-coding RNAs and programmed cell death in colorectal cancer: implications for targeted therapy

BACKGROUND

Colorectal cancer (CRC) remains one of the most common causes of cancer-related mortality worldwide. Its progression is influenced by complex interactions involving genetic, epigenetic, and environmental factors. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have been identified as key regulators of gene expression, affecting diverse biological processes, notably programmed cell death (PCD).

OBJECTIVE

This review aims to explore the relationship between ncRNAs and PCD in CRC, focusing on how ncRNAs influence cancer cell survival, proliferation, and treatment resistance.

METHODS

A comprehensive literature analysis was conducted to examine recent findings on the role of ncRNAs in modulating various PCD mechanisms, including apoptosis, autophagy, necroptosis, and pyroptosis, and their impact on CRC development and therapeutic response.

RESULTS

ncRNAs were found to significantly regulate PCD pathways, impacting tumor growth, metastasis, and treatment sensitivity in CRC. Their influence on these pathways highlights the potential of ncRNAs as biomarkers for early CRC detection and as targets for innovative therapeutic interventions.

CONCLUSION

Understanding the involvement of ncRNAs in PCD regulation offers new insights into CRC biology. The targeted modulation of ncRNA-PCD interactions presents promising avenues for personalized cancer treatment, which may improve patient outcomes by enhancing therapeutic effectiveness and reducing resistance.

Iron homeostasis and neurodegeneration in the ageing brain: Insight into ferroptosis pathways

Ageing is a major risk factor for various chronic diseases and offers a potential target for developing novel and broadly effective preventatives or therapeutics for age-related conditions, including those affecting the brain. Mechanisms contributing to ageing have been summarized as the hallmarks of ageing, with iron imbalance being one of the major factors. Ferroptosis, an iron-mediated lipid peroxidation-induced programmed cell death, has recently been implicated in neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). Addressing ferroptosis offers both opportunities and challenges for treating neurodegenerative diseases, though the specific mechanisms remain unclear. This research explores the key processes behind how ferroptosis contributes to brain ageing, with a focus on the complex signaling networks that are involved. The current article aims to uncover that how ferroptosis, a specific type of cell death, may drive age-related changes in the brain. Additionally, the article also unveils its role in neurodegenerative diseases, discussing how understanding these mechanisms could open up new therapeutic avenues.

Designing Nano-Hemin for Ferroptosis-Mediated Cell Death via Enzymatic Hemin Digestion

Hemin is a protoporphyrin complex of ferric ion which catalyzes H2O2 degradation and produces reactive oxygen species (ROS). This ROS generation property induces oxidative stress to hemin-exposed cells that can lead to various situations such as intracellular Fenton reaction, ferroptosis, or autophagy. Therapeutic performance of hemin is hindered due to low bioavailability of the active monomeric form with an intact ROS generation property. Here, we demonstrate a colloidal nanoparticle form of hemin (nano-hemin) with a high ROS generation property and high cell uptake property. We have shown that nano-hemin produces ROS inside a cell that upregulate heme oxygenase-1 in order to metabolize hemin. This leads to the ferroptosis-mediated cell death. Furthermore, we show that the ROS generation property of nano-hemin can be modulated to control hemin cytotoxicity for either ferroptosis or autophagy. Our findings suggest that nano-hemin can be designed with modular cytotoxicity for different therapeutic applications.

Lactate activates ER stress to promote alveolar epithelial cells apoptosis in pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic, progressive lung disease characterized by fibroblast proliferation, extensive extracellular matrix and collagen deposition, accompanied by inflammatory damage, ultimately leading to death due to respiratory failure. Endoplasmic reticulum (ER) stress in pulmonary fibrotic tissue is indeed recognized as a significant factor exacerbating PF development. Emerging evidences indicated a potential association between ER stress induced by lactate and cellular apoptosis in PF. However, the mechanisms in this process need further elucidation. In this paper, pulmonary fibrosis model was induced by bleomycin (BLM) intratracheally in mice. In the cellular model, type II epithelial cells were treated by lactate and TGF-β to detect ER stress and apoptosis markers. Lactate could promote ER stress response and apoptosis. Mechanically, lactate activated Caspase-12 via ATF4-Chop axis to induce cell apoptosis and promote fibrosis. ER stress inhibitor could effectively suppress alveolar epithelial cells apoptosis and pulmonary fibrosis. We concluded that pro-fibrotic properties of lactate are associated with alveolar epithelial cells apoptosis by causing ER stress and thus provide new potential therapeutic targets for pulmonary fibrosis.

PANoptosis Regulation in Reservoir Hosts of Zoonotic Viruses

Zoonotic viruses originating from reservoir hosts, such as bats and birds, often cause severe illness and outbreaks amongst humans. Upon zoonotic virus transmission, infected cells mount innate immune responses that include the activation of programmed cell death pathways to recruit innate immune cells to the site of infection and eliminate viral replication niches. Different inflammatory and non-inflammatory cell death pathways, such as pyroptosis, apoptosis, necroptosis, and PANoptosis can undergo concurrent activation in humans leading to mortality and morbidity during zoonosis. While controlled activation of PANoptosis is vital for viral clearance during infection and restoring tissue homeostasis, uncontrolled PANoptosis activation results in immunopathology during zoonotic virus infections. Intriguingly, animal reservoirs of zoonotic viruses, such as bats and birds, appear to have a unique immune tolerance adaptation, allowing them to host viruses without succumbing to disease. The mechanisms facilitating high viral tolerance in bats and birds are poorly understood. In this perspective review, we discuss the regulation of PANoptotic pathways in bats and birds and indicate how they co-exist with viruses with mild clinical signs and no immunopathology. Understanding the PANoptotic machinery of bats and birds may thus assist us in devising strategies to contain zoonotic outbreaks amongst humans.

Cuproptosis and Cuproptosis-Based Synergistic Therapy for Cancer Treatment

Copper, as an essential trace nutrient for human, plays a crucial role in numerous cellular activities, and is vital for maintaining homeostasis in organisms. Deviations from normal intracellular copper concentration range can disrupt the cellular homeostasis and lead to cell death. Cell death is the process in which cells lose their vitality and cannot sustain normal metabolism, which has various forms. The recently discovered cuproptosis mechanism differs from the previously recognized forms, which is triggered by intracellular copper accumulation. The discovery of cuproptosis has sparked interest among researchers, and this mechanism has been applied in the treatment of various intractable diseases, including different types of cancer. However, the developed cuproptosis-based therapies have revealed certain limitations, such as low immunostimulatory efficiency, poor tumor targeting, and inhibition by the tumor microenvironment. Therefore, researchers are devoted to combining cuproptosis with existing cancer therapies to develop more effective synergistic cancer therapies. This review summarizes the latest research advancements in the cuproptosis-based therapies for various types of cancer, with a focus on the synergistic cancer therapies. Finally, it provides an outlook on the future development of cuproptosis in anti-tumor therapy.

BPA induces testicular damage in male rodents via apoptosis, autophagy, and ferroptosis

Bisphenol A (BPA), chemically known as 2,2-bis(4-hydroxyphenyl) propane, is one of the most common endocrine-disrupting chemicals in our environment. Long-term or high-dose exposure to BPA may lead to testicular damage and adversely affect male reproductive function. In vivo studies on rodents have demonstrated that BPA triggers apoptosis in testicular cells through both intrinsic and extrinsic pathways. Further in vitro studies on spermatogonia, Sertoli cells, and Leydig cells have all confirmed the pro-apoptotic effects of BPA. Given these findings, apoptosis is considered a primary mode of cell death induced by BPA in testicular tissue. In addition, BPA promotes autophagy by altering the activity of the Akt/mTOR pathway and upregulating the expression of autophagy-related genes and proteins. Recent studies have also identified ferroptosis as a significant contributing factor to BPA-induced testicular damage, further complicating the landscape of BPA's effects. This review summarizes natural substances that mitigate BPA-induced testicular damage by inhibiting these cell death pathways. These findings not only highlight potential therapeutic strategies but also underscore the need for further research into the underlying mechanisms of BPA-induced toxicity, particularly as it pertains to human health risk assessment and the development of more effective BPA management strategies.

Advances in the application of logic gates in nanozymes

Nanozymes are a class of nanomaterials with biocatalytic function and enzyme-like activity, whose advantages include high stability, low cost, and mass production. They can catalyze the substrates of natural enzymes based on specific nanostructures and serve as substitutes for natural enzymes. Their applied research involves a wide range of fields such as biomedicine, environmental governance, agriculture, and food. Molecular logic gates are a new cross-disciplinary discipline, which can simulate the function of silicon circuits on a molecular scale, perform single or multiple input logic operations, and generate logic outputs. A molecular logic gate is a binary operation that converts an input signal into an output signal according to the rules of Boolean logic, generating two signals, a high level, and a low level. The high and low levels represent the "true" and "false" values of the logic gates, and their outputs correspond to "l" and "0" of the molecular logic gates, respectively. The combination of nanozymes and logic gates is a novel and attractive research direction, and the cross-application of the two brings new opportunities and ideas for various fields, such as the construction of efficient biocomputers, intelligent drug delivery systems, and the precise diagnosis of diseases. This review describes the application of logic gates based on nanozymes, which is expected to provide a certain theoretical foundation for researchers' subsequent studies.

Comparison of Malondialdehyde, Acetylcholinesterase, and Apoptosis-Related Markers in the Cortex and Hippocampus of Cognitively Dysfunctional Mice Induced by Scopolamine

Objectives: Until now, many researchers have conducted evaluations on hippocampi for analyses of cognitive dysfunction models using scopolamine. However, depending on the purposes of these analyses, there are differences in the experimental results for the hippocampi and cortexes. Therefore, this study intends to compare various analyses of cognitive dysfunction after scopolamine administration with each other in hippocampi and cortexes. Methods: Scopolamine was administered at three dosages in mice: 0.5, 1, and 3 mg/kg. And this study evaluates the differences in cognitive function and the expression of malondialdehyde (MDA), acetylcholinesterase (AChE), and brain-derived neurotrophic factor (BDNF) in mice's hippocampi and cortexes based on scopolamine dosages. Results: The Morris water maze test was conducted between 1 and 3 h after scopolamine injection to assess its duration. A significant decrease in behavioral ability was evaluated at 1 h, and we observed a similar recovery to the normal group at 3 h. And the Morris water maze escape latency showed differences depending on scopolamine concentration. While the escape waiting time in the control group and scop 0.5 administration group remained similar to that seen before administration, the administration of scop 1 and 3 increased it. In the experimental group administered scop 1 and 3, cerebral MDA levels in the cerebral cortex significantly increased. In the hippocampus, the MDA level in the scopolamine-administered groups slightly increased compared to the cortex. A Western blotting assay shows that Bax and Bcl-xl showed a tendency to increase or decrease depending on the concentration, but BDNF increased in scop 0.5, and scop 1 and 3 did not show a significant decrease compared to the control at the cerebral cortex. In the hippocampus, BDNF showed a concentration-dependent decrease in expression. Conclusions: This study's findings indicate that chemical analyses for MDA and AChE can be performed in the cerebral cortex, while the hippocampus is better suited for protein analysis of apoptosis and BDNF.

Marine Staurosporine Analogues: Activity and Target Identification in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with high mortality and drug resistance and no targeted drug available at present. Compound 4, a staurosporine alkaloid derived from Streptomyces sp. NBU3142 in a marine sponge, exhibits potent anti-TNBC activity. This research investigated its impact on MDA-MB-231 cells and their drug-resistant variants. The findings highlighted that compound 4 inhibits breast cancer cell migration, induces apoptosis, arrests the cell cycle, and promotes cellular senescence in both regular and paclitaxel-resistant MDA-MB-231 cells. Additionally, this study identified mitogen-activated protein kinase kinase kinase 11 (MAP3K11) as a target of compound 4, implicating its role in breast tumorigenesis by affecting cell proliferation, migration, and cell cycle progression.

p,p'-DDT induces apoptosis in human endometrial stromal cells via the PI3K/AKT pathway and oxidative stress

OBJECTIVE

Bis-[4-chlorophenyl]-1,1,1-trichloroethane (DDT), one of the most widely used synthetic pesticides, is an endocrine-disrupting chemical with the potential to interfere with the human reproductive system. The effects of DDT and one of its metabolites, p,p'-DDT, on human endometrial stromal cells (ESCs) and health outcomes remain unknown. In this study, we investigated whether p,p'-DDT induces an imbalance in cell proliferation and apoptosis in human ESCs via oxidative stress.

METHODS

We assessed apoptosis in ESCs by quantifying the expression of markers associated with both intrinsic and extrinsic pathways. Additionally, we measured levels of reactive oxygen species (ROS), antioxidant enzyme activity, and estrogen receptors (ERs). We also examined changes in signaling involving nuclear factor kappa-light-chain-enhancer of activated B cells.

RESULTS

Following treatment with 1,000 pg/mL of p,p'-DDT, we observed an increase in Bax expression, a decrease in Bcl-2 expression, and increases in the expression of caspases 3, 6, and 8. We also noted a rise in the generation of ROS and a reduction in glutathione peroxidase expression after treatment with p,p'-DDT. Additionally, p,p'-DDT treatment led to changes in ER expression and increases in the protein levels of phosphatidylinositol 3-kinase (PI3K), phospho-protein kinase B (phospho-AKT), and phospho-extracellular signal-regulated kinase (phospho-ERK).

CONCLUSION

p,p'-DDT was found to induce apoptosis in human ESCs through oxidative stress and an ER-mediated pathway. The activation of the PI3K/AKT and ERK pathways could represent potential mechanisms by which p,p'-DDT prompts apoptosis in human ESCs and may be linked to endometrial pathologies.

A Narrative Review: Immunometabolic Interactions of Host-Gut Microbiota and Botanical Active Ingredients in Gastrointestinal Cancers

The gastrointestinal tract is where the majority of gut microbiota settles; therefore, the composition of the gut microbiota and the changes in metabolites, as well as their modulatory effects on the immune system, have a very important impact on the development of gastrointestinal diseases. The purpose of this article was to review the role of the gut microbiota in the host environment and immunometabolic system and to summarize the beneficial effects of botanical active ingredients on gastrointestinal cancer, so as to provide prospective insights for the prevention and treatment of gastrointestinal diseases. A literature search was performed on the PubMed database with the keywords "gastrointestinal cancer", "gut microbiota", "immunometabolism", "SCFAs", "bile acids", "polyamines", "tryptophan", "bacteriocins", "immune cells", "energy metabolism", "polyphenols", "polysaccharides", "alkaloids", and "triterpenes". The changes in the composition of the gut microbiota influenced gastrointestinal disorders, whereas their metabolites, such as SCFAs, bacteriocins, and botanical metabolites, could impede gastrointestinal cancers and polyamine-, tryptophan-, and bile acid-induced carcinogenic mechanisms. GPRCs, HDACs, FXRs, and AHRs were important receptor signals for the gut microbial metabolites in influencing the development of gastrointestinal cancer. Botanical active ingredients exerted positive effects on gastrointestinal cancer by influencing the composition of gut microbes and modulating immune metabolism. Gastrointestinal cancer could be ameliorated by altering the gut microbial environment, administering botanical active ingredients for treatment, and stimulating or blocking the immune metabolism signaling molecules. Despite extensive and growing research on the microbiota, it appeared to represent more of an indicator of the gut health status associated with adequate fiber intake than an autonomous causative factor in the prevention of gastrointestinal diseases. This study detailed the pathogenesis of gastrointestinal cancers and the botanical active ingredients used for their treatment in the hope of providing inspiration for research into simpler, safer, and more effective treatment pathways or therapeutic agents in the field.

Chronic prostatitis/chronic pelvic pain syndrome impairs erectile function by inducing apoptosis in a rat model of experimental autoimmune prostatitis

Over the years, numerous epidemiological studies have shown that chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) promotes erectile dysfunction. Nonetheless, the precise underlying mechanism remains to be fully clarified. The objective of this research was to identify crucial signaling pathways responsible for CP/CPPS-induced erectile dysfunction. Thirty 8-week-old male Sprague‒Dawley rats were randomly assigned to either the CP/CPPS model group or the control group. The CP/CPPS rat model was established through subcutaneous injection of a combination of rat prostate protein and Freund's adjuvant. Penile erectile function assessment was conducted 45 days after immunization through electrical stimulation of the cavernous nerve. RNA sequencing of the corpus cavernosum of the penis was then performed using the Kyoto Encyclopedia of Genes and Genomes and protein‒protein interaction network analysis. Western blotting was performed on the cavernous tissue. Cell apoptosis assays, cell counting kit-8 assays, cell cloning assays, and Western blotting were conducted on rat endothelial cells. Erectile function was significantly lower in the CP/CPPS model group than in the control group (p < 0.001). Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that differentially expressed genes were predominantly enriched in the apoptosis pathway. Moreover, an increase in apoptosis in the rat corpus cavernosum, along with a decrease in the protein expression of CD31 (p = 0.0089) and eNOS (p = 0.0069) following CP/CPPS induction, was observed. In a protein‒protein interaction network, Pitx2 was recognized as a central gene. The role of Pitx2 in regulating apoptosis was demonstrated in experiments using rat endothelial cell lines, and it was found to be regulated by the Wnt/β-catenin pathway. This study highlights the occurrence of cavernous endothelial cell apoptosis in CP/CPPS-induced erectile dysfunction, and the potential mechanism of apoptosis may involve inhibition of the Wnt/β-catenin/Pitx2 pathway.

Modeling the heterogeneous apoptotic response of caspase-mediated signaling in tumor cells

Resisting apoptosis is a hallmark of cancer. For this reason, it may be possible to force cancer cells to die by targeting components along the apoptotic signaling pathway. However, apoptosis signaling is challenging to understand due to dynamic and complex behaviors of ligands, receptors, and intracellular signaling components in response to cancer therapy. In this work, we forecast the apoptotic response based on the combined impact of these features. We expanded a previously established mathematical model of caspase-mediated apoptosis to include extracellular activation and receptor dynamics. In addition, three potential threshold values of caspase-3 necessary for the activation of apoptosis were selected to forecast which cells become apoptotic over time. We first vary ligand and receptor levels with the number of intracellular signaling proteins remaining consistent. Then, we vary the intracellular protein molecules in each simulated tumor cell to forecast the response of a heterogeneous population. By leveraging the benefits of computational modeling, we investigate the combined effect of several factors on the onset of apoptosis. This work provides quantitative insights for how the apoptotic signaling response can be forecasted, and precisely triggered, amongst heterogeneous cells via extracellular activation.

Morin attenuates arsenic-induced toxicity in 3T3 embryonic fibroblast cells by suppressing oxidative stress, inflammation, and apoptosis: In vitro and silico evaluations

This study aims to investigate the curative effects of Morin, a flavonoid, against arsenic toxicity in 3T3 embryonic fibroblast cells and its effect on the molecular mechanisms of cells. The cytotoxicity and viability of the cells were measured by MTT and LDH tests. Arsenic (0.74 μM) was used to trigger toxicity and Morin (50 μM) was used for treatment. The levels of oxidative stress biomarkers and the activities of antioxidant enzymes were measured by spectrophotometric method, and inflammatory markers were measured by ELISA method. While mRNA expression levels of Bax, Bcl-2 levels, and Caspase-3 activity were measured by qRT-PCR technique, TUNEL staining was performed to detect DNA breaks and DAPI staining to visualize nuclear changes. Protein structures were retrieved from the protein data bank. OpenBabel and Autodock programs were used for the molecular docking study. Morin rescued the 3T3 embryonic fibroblast cells exposed to arsenic. However, Arsenic decreased the activities of antioxidant enzymes in cells and significantly increased oxidative stress, inflammation, and apoptosis. Morin treatment reduced oxidative damage and TNF-α and IL-1β levels. Arsenic-induced Caspase-3 mRNA expression level and Bax protein mRNA expression level were significantly increased, while Bcl-2 mRNA expression level was significantly decreased. While Caspase-3 mRNA expression level and Bax protein mRNA expression level decreased with morin treatment, Bcl-2 mRNA expression level increased significantly. Molecular docking study results showed good binding affinity of morin in SOD, GSH-Px, Bax, Bcl-2, Caspase-3, TNF-α, and IL-1β structures. Morin showed antioxidant, anti-inflammatory, and anti-apoptotic effects against Arsenic-induced cellular toxicity.

Knockdown of iPLA2γ enhances cisplatin-induced apoptosis by increasing ROS-dependent peroxidation of mitochondrial phospholipids in bladder cancer cells

Cisplatin (CDDP) is a platinum-based drug with anti-cancer activity and is widely used as a standard therapy for bladder cancer. It is well known that CDDP causes cell death by increasing the generation of reactive oxygen species (ROS) and lipid peroxidation, but the mechanism of its anti-cancer effects has not been fully elucidated. There are still some problems such as chemoresistance in CDDP therapy. In the present study, we found the expression of Ca2+-independent phospholipase A2γ (iPLA2γ), which has been reported to regulate cellular redox homeostasis by inhibiting lipid peroxide accumulation, in human bladder cancer tissues. Thus, we investigated the effect of iPLA2γ knockdown on CDDP-induced bladder cancer cell death. As a result, we found that iPLA2γ knockdown significantly enhanced CDDP-induced apoptosis, intracellular and mitochondrial ROS production, cytochrome c release and caspase activation in bladder cancer cells. Moreover, mitochondrial membrane potential was decreased and peroxidation of mitochondrial phospholipids was increased by iPLA2γ knockdown. It was also shown that co-treatment of bromoenol lactone, an iPLA2 inhibitor, increased CDDP-induced apoptosis. These results indicated that iPLA2γ plays an important role in protecting bladder cancer cells from CDDP-induced apoptosis, and that iPLA2γ inhibitors might represent a novel strategy in CDDP-based multi-drug therapy.

ARTS and small-molecule ARTS mimetics upregulate p53 levels by promoting the degradation of XIAP

Mutations resulting in decreased activity of p53 tumor suppressor protein promote tumorigenesis. P53 protein levels are tightly regulated through the Ubiquitin Proteasome System (UPS). Several E3 ligases were shown to regulate p53 stability, including MDM2. Here we report that the ubiquitin E3 ligase XIAP (X-linked Inhibitors of Apoptosis) is a direct ligase for p53 and describe a novel approach for modulating the levels of p53 by targeting the XIAP pathway. Using in vivo (live-cell) and in vitro (cell-free reconstituted system) ubiquitylation assays, we show that the XIAP-antagonist ARTS regulates the levels of p53 by promoting the degradation of XIAP. XIAP directly binds and ubiquitylates p53. In apoptotic cells, ARTS inhibits the ubiquitylation of p53 by antagonizing XIAP. XIAP knockout MEFs express higher p53 protein levels compared to wild-type MEFs. Computational screen for small molecules with high affinity to the ARTS-binding site within XIAP identified a small-molecule ARTS-mimetic, B3. This compound stimulates apoptosis in a wide range of cancer cells but not normal PBMC (Peripheral Blood Mononuclear Cells). Like ARTS, the B3 compound binds to XIAP and promotes its degradation via the UPS. B3 binding to XIAP stabilizes p53 by disrupting its interaction with XIAP. These results reveal a novel mechanism by which ARTS and p53 regulate each other through an amplification loop to promote apoptosis. Finally, these data suggest that targeting the ARTS binding pocket in XIAP can be used to increase p53 levels as a new strategy for developing anti-cancer therapeutics.

Chemical synthetic approaches to mimic the TRAIL: promising cancer therapeutics

Apoptosis is programmed cell death that eliminates undesired cells to maintain homeostasis in metazoan. Aberration of this process may lead to cancer genesis. The tumor necrosis factor related apoptosis inducing ligand (TRAIL) induces apoptosis in cancer cells after ligation with death receptors (DR4/DR5) while sparing most normal cells. Therefore, strategies to induce apoptosis in cancer cells by mimicking the TRAIL emerge as a promising therapeutic tool. Hence, approaches are taken to develop TRAIL/DR-based cancer therapeutics. The recombinant soluble TRAIL (rhTRAIL) and death receptor agonistic antibodies were produced and tested pre-clinically and clinically. Pre-clinical and clinical trial data demonstrate that these therapeutics are safe and relatively well tolerated. But some of these therapeutics failed to exert adequate efficacy in clinical settings. Besides these biotechnologically derived therapeutics, a few chemically synthesized therapeutics are reported. Some of these therapeutics exert considerable efficacy in vitro and in vivo. In this review, we will discuss chemically synthesized TRAIL/DR-based therapeutics, their chemical and biological behaviour, design concepts and strategies that may contribute to further improvement of TRAIL/DR-based therapeutics.

Effect of Flammulina velutipes polysaccharide on mitochondrial apoptosis in lung adenocarcinoma A549 cells

FVP is a polysaccharide extracted from Flammulina velutipes with immunomodulatory, anti-tumor, and anti-oxidation activities. In this study, we obtained the crude polysaccharide FVP-C from the water extract of Flammulina velutipes, and its main component FVP-S1 was obtained after further purification. Upon structural identification, we found that FVP-C is a neutral polysaccharide, and FVP-S1 was an acidic golden mushroom polysaccharide, consisting of glucuronic acid, xylose, and glucose. Lung adenocarcinoma (A549) was treated with FVP-S1 and FVP-C, respectively, and we found that FVP-S1 and FVP-C inhibited the proliferation and migration ability of tumor cells, as well as changed the morphology of the tumor cells and caused chromosome sheteropythosis, among which FVP-S1 had the best inhibition effect. The results of flow cytometry experiments and mitochondrial membrane potential, RT-qPCR, and Western blot showed that FVP-S1 and FVP-C were able to decrease the mitochondrial membrane potential, increase the expression level of apoptotic proteins Casepase-3 and Casepase-9 proteins, and at the same time, increase the ratio of Bax and Bcl-2, which promoted apoptosis of tumor cells. In conclusion, these data indicated that FVP-S1 and FVP-C were able to induce apoptosis in A549 cells through the mitochondrial pathway, which played an important role in inhibiting tumor cells.

Utilising a 1,8-naphthalimide probe for the ratiometric fluorescent visualisation of caspase-3

The development of selective and sensitive probes for monitoring caspase-3 activity-a critical enzyme involved in apoptosis-remains an area of significant interest in biomedical research. Herein, we report the synthesis and characterisation of a novel ratiometric fluorescent probe, Ac-DEVD-PABC-Naph, designed to detect caspase-3 activity. The probe utilises a 1,8-naphthalimide fluorophore covalently linked to a peptide sequence via a self-immolative p-aminobenzyl alcohol (PABA) linker. Upon enzymatic cleavage by caspase-3, the probe undergoes spontaneous degradation, releasing the free naphthalimide fluorophore, resulting in a ratiometric change in fluorescence emission. Spectroscopic studies revealed a time-dependent ratiometric fluorescent response, demonstrating the probe's ability to visualise caspase-3 activity with high sensitivity. Enzyme kinetics such as K m (Michaelis constant), k cat (turnover number), and LOD (Limit of Detection) were obtained, suggesting that the probe possesses comparable kinetic data to other probes in literature, but with the added benefits of ratiometric detection. Selectivity studies also demonstrated the probe's specificity for caspase-3 over other endogenous species and enzymes. Ac-DEVD-PABC-Naph may be a promising tool for the quantitative detection and fluorescent visualisation of caspase-3 activity in biological systems, with potential applications in apoptosis research and drug development.

SHED-exos promote saliva secretion by suppressing p-ERK1/2-mediated apoptosis in glandular cells

OBJECTIVES

Confirm that stem cells from human exfoliated deciduous teeth-derived exosomes (SHED-exos) can limit inflammation-triggered epithelial cell apoptosis and explore the molecular mechanism.

METHODS

SHED-exos were injected into the submandibular glands (SMGs) of non-obese diabetic (NOD) mice, an animal model of Sjögren's syndrome (SS). Cell death was evaluated by western blotting and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling staining.

RESULTS

SHED-exos treatment promoted the saliva flow rates of NOD mice, accompanied by decreased cleaved caspase-3 levels and apoptotic cell numbers in SMGs. SHED-exos inhibited autophagy, pyroptosis, NETosis, ferroptosis, necroptosis and oxeiptosis marker expression in SS-damaged glands. Mechanistically, Kyoto Encyclopedia of Genes and Genomes analysis of exosomal miRNAs suggested that the rat sarcoma virus (RAS)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway might play an important role. In vivo, the expression of Kirsten RAS, Harvey RAS, MEK1/2 and p-ERK1/2 was upregulated in SMGs, and this change was blocked by SHED-exos treatment. In vitro, SHED-exos suppressed p-ERK1/2 activation and increased cleaved caspase-3 and apoptotic cell numbers, which were induced by IFN-γ.

CONCLUSION

SHED-exos suppress epithelial cell death, which is responsible for promoting salivary secretion. SHED-exos inhibited inflammation-triggered epithelial cell apoptosis by suppressing p-ERK1/2 activation, which is involved in these effects.

Artificial keloid skin models: understanding the pathophysiological mechanisms and application in therapeutic studies

Keloid is a type of scar formed by the overexpression of extracellular matrix substances from fibroblasts following inflammation after trauma. The existing keloid treatment methods include drug injection, surgical intervention, light exposure, cryotherapy, etc. However, these methods have limitations such as recurrence, low treatment efficacy, and side effects. Consequently, studies are being conducted on the treatment of keloids from the perspective of inflammatory mechanisms. In this study, keloid models are created to understand inflammatory mechanisms and explore treatment methods to address them. While previous studies have used animal models with gene mutations, chemical treatments, and keloid tissue transplantation, there are limitations in fully reproducing the characteristics of keloids unique to humans, and ethical issues related to animal welfare pose additional challenges. Consequently, studies are underway to create in vitro artificial skin models to simulate keloid disease and apply them to the development of treatments for skin diseases. In particular, herein, scaffold technologies that implement three-dimensional (3D) full-thickness keloid models are introduced to enhance mechanical properties as well as biological properties of tissues, such as cell proliferation, differentiation, and cellular interactions. It is anticipated that applying these technologies to the production of artificial skin for keloid simulation could contribute to the development of inflammatory keloid treatment techniques in the future.

Increased molar ratio of free fatty acids to albumin in blood as cause and early biomarker for the development of cataracts and Alzheimer's disease

Cataracts and Alzheimer's disease (AD) are closely linked and are associated with aging and with systemic diseases that increase the molar ratio of free fatty acids to albumin (mFAR) in the blood. From the results of our earlier studies on the development of senile cataracts and from results recently published in the literature on the pathogenesis of Alzheimer's disease, we suggest that there is a common lipotoxic cascade for both diseases, explaining the strong connection between aging, an elevated mFAR in the blood, cataract formation, and AD. Long-chain free fatty acids (FFA) are transported in the blood as FFA/albumin complexes. In young people, vascular albumin barriers in the eyes and brain, very similar in their structure and effect, reduce the FFA/albumin complex concentration from around 650 μmol/l in the blood to 1-3 μmol/l in the aqueous humour of the eyes as well as in the cerebrospinal fluid of the brain. At such low concentrations the fatty acid uptake of the target cells - lens epithelial and brain cells - rises with increasing FFA/albumin complex concentrations, especially when the fatty acid load of albumin molecules is mFAR>1. At higher albumin concentrations, for instance in blood plasma or the interstitial tissue spaces, the fatty acid uptake of the target cells becomes increasingly independent of the FFA/albumin complex concentration and is mainly a function of the mFAR (Richieri et al., 1993). In the blood plasma of young people, the mFAR is normally below 1.0. In people over 40 years old, aging increases the mFAR by decreasing the plasma concentration of albumin and enhancing the plasma concentrations of FFA. The increase in the mFAR in association with C6-unsaturated FFA are risk factors for the vascular albumin barriers (Hennig et al., 1984). Damage to the vascular albumin barrier in the eyes and brain increases the concentration of FFA/albumin complex in the aqueous humour as well as in the cerebrospinal fluid, leading to mitochondrial dysfunction and the death of lens epithelial and brain cells, the development of cataracts, and AD. An age-dependent increase in the concentration of FFA/albumin complex has been found in the aqueous humour of 177 cataract patients, correlating with the mitochondria-mediated apoptotic death of lens epithelial cells, lens opacification and cataracts (Iwig et al., 2004). Mitochondrial dysfunction is also an early crucial event in Alzheimer's pathology, closely connected with the generation of amyloid beta peptides (Leuner et al., 2012). Very recently, amyloid beta production has also been confirmed in the lenses of Alzheimer's patients, causing cataracts (Moncaster et al., 2022). In view of this, we propose that there is a common lipotoxic cascade for senile cataract formation and senile AD, initiated by aging and/or systemic diseases, leading to an mFAR>1 in the blood.

Thiazolidinone-linked-1,2,3-triazoles with (R)-Carvone as new potential anticancer agents

Aim: This study explores the cytotoxic and apoptotic effects of novel thiazolidinone-1,2,3-triazole hybrids on HT-1080, A-549, and MDA-MB-231 cancer cell lines.Methods & results: The synthesized compounds underwent comprehensive characterization (NMR and HRMS) to confirm their structures and purity. Subsequent anticancer activity screening across diverse cancer cell lines revealed promising antitumor potential notably, compounds 6f and 6g. Mechanistic investigations unveiled that compound 6f triggers apoptosis through the caspase-3/7 pathway. In terms of in silico studies, the compound 6f was identified as a potent inhibitor of caspase-3 and caspase-7.Conclusion: The present study underscores the therapeutic potential of thiazolidinone-1,2,3-triazole hybrids against certain cancer cells. These findings highlight a promising avenue for the development of cancer treatment strategies utilizing these (R)-Carvone-based derivatives.

Targeting programmed cell death in inflammatory bowel disease through natural products: New insights from molecular mechanisms to targeted therapies

Inflammatory bowel disease (IBD) is an autoimmune disorder primarily characterized by intestinal inflammation and recurrent ulceration, leading to a compromised intestinal barrier and inflammatory infiltration. This disorder's pathogenesis is mainly attributed to extensive damage or death of intestinal epithelial cells, along with abnormal activation or impaired death regulation of immune cells and the release of various inflammatory factors, which contribute to the inflammatory environment in the intestines. Thus, maintaining intestinal homeostasis hinges on balancing the survival and functionality of various cell types. Programmed cell death (PCD) pathways, including apoptosis, pyroptosis, autophagy, ferroptosis, necroptosis, and neutrophil extracellular traps, are integral in the pathogenesis of IBD by mediating the death of intestinal epithelial and immune cells. Natural products derived from plants, fruits, and vegetables have shown potential in regulating PCD, offering preventive and therapeutic avenues for IBD. This article reviews the role of natural products in IBD treatment by focusing on targeting PCD pathways, opening new avenues for clinical IBD management.

Multidimensional Transcriptomics Unveils RNF34 as a Prognostic Biomarker and Potential Indicator of Chemotherapy Sensitivity in Wilms' Tumour

Nephroblastoma, colloquially known as Wilms' tumour (WT), is the predominant malignant renal neoplasm arising in the paediatric population. Modern therapeutic approaches for WT incorporate a synergistic combination of surgical intervention, radiotherapy, and chemotherapy, which substantially ameliorate the overall patient survival rate. Despite this, the optimal sequence of chemotherapy and surgical intervention remains a matter of contention, with each strategy presenting its own strengths and weaknesses that could influence clinical decision-making. To make some headway on this clinical dilemma, we deployed a multidimensional transcriptomics integration approach by analysing bulk RNA sequencing data with 136 samples, as well as single-nucleus RNA sequencing (snRNA-seq) and paired spatial transcriptome sequencing (stRNA) data from 32 WT specimens. Our findings identified a distinct elevation of RNF34 expression within WT samples, which correlated with unfavourable prognostic outcomes. Leveraging the Genomics of Drug Sensitivity in Cancer (GDSC), we simultaneously revealed that patients with high expression of RNF34 have higher sensitivity to commonly used chemotherapy drugs for WT. Furthermore, our analysis of snRNA and stRNA data unveiled a reduced proportion of RNF34 expression in neoplastic cells after chemotherapy. Moreover, stRNA data delineated a significant association between a higher proportion of RNF34 expression in cancer cells and adverse features such as anaplastic histology and tumour recurrence. Intriguingly, we also observed a close association between elevated RNF34 expression and a characteristic exhausted tumour immune microenvironment. Collectively, our findings underscore the pivotal role of RNF34 in the prognostic prediction potential and treatment sensitivity of WT. This comprehensive analysis can potentially inform and refine clinical decision-making for WT patients and guide future studies towards the development of optimized, rational therapeutic strategies.

The dual role of mesenchymal stem cells in apoptosis regulation

Mesenchymal stem cells (MSCs) are widely distributed pluripotent stem cells with powerful immunomodulatory capacity. MSCs transplantation therapy (MSCT) is widely used in the fields of tissue regeneration and repair, and treatment of inflammatory diseases. Apoptosis is an important way for tissues to maintain cell renewal, but it also plays an important role in various diseases. And many studies have shown that MSCs improves the diseases by regulating cell apoptosis. The regulation of MSCs on apoptosis is double-sided. On the one hand, MSCs significantly inhibit the apoptosis of diseased cells. On the other hand, MSCs also promote the apoptosis of tumor cells and excessive immune cells. Furthermore, MSCs regulate apoptosis through multiple molecules and pathways, including three classical apoptotic signaling pathways and other pathways. In this review, we summarize the current evidence on the regulation of apoptosis by MSCs.

Oxytosis/Ferroptosis in Neurodegeneration: the Underlying Role of Master Regulator Glutathione Peroxidase 4 (GPX4)

Oxytosis/ferroptosis is an iron-dependent oxidative form of cell death triggered by lethal accumulation of phospholipid hydroperoxides (PLOOHs) in membranes. Failure of the intricate PLOOH repair system is a principle cause of ferroptotic cell death. Glutathione peroxidase 4 (GPX4) is distinctly vital for converting PLOOHs in membranes to non-toxic alcohols. As such, GPX4 is known as the master regulator of oxytosis/ferroptosis. Ferroptosis has been implicated in a number of disorders such as neurodegenerative diseases (amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD), etc.), ischemia/reperfusion injury, and kidney degeneration. Reduced function of GPX4 is frequently observed in degenerative disorders. In this study, we examine how diminished GPX4 function may be a critical event in triggering oxytosis/ferroptosis to perpetuate or initiate the neurodegenerative diseases and assess the possible therapeutic importance of oxytosis/ferroptosis in neurodegenerative disorders. These discoveries are important for advancing our understanding of neurodegenerative diseases because oxytosis/ferroptosis may provide a new target to slow the course of the disease.

Cyclic peptides discriminate BCL-2 and its clinical mutants from BCL-XL by engaging a single-residue discrepancy

Overexpressed pro-survival B-cell lymphoma-2 (BCL-2) family proteins BCL-2 and BCL-XL can render tumor cells malignant. Leukemia drug venetoclax is currently the only approved selective BCL-2 inhibitor. However, its application has led to an emergence of resistant mutations, calling for drugs with an innovative mechanism of action. Herein we present cyclic peptides (CPs) with nanomolar-level binding affinities to BCL-2 or BCL-XL, and further reveal the structural and functional mechanisms of how these CPs target two proteins in a fashion that is remarkably different from traditional small-molecule inhibitors. In addition, these CPs can bind to the venetoclax-resistant clinical BCL-2 mutants with similar affinities as to the wild-type protein. Furthermore, we identify a single-residue discrepancy between BCL-2 D111 and BCL-XL A104 as a molecular "switch" that can differently engage CPs. Our study suggests that CPs may inhibit BCL-2 or BCL-XL by delicately modulating protein-protein interactions, potentially benefiting the development of next-generation therapeutics.

CD1d protects against hepatocyte apoptosis in non-alcoholic steatohepatitis

BACKGROUND & AIMS

Hepatocyte apoptosis, a well-defined form of cell death in non-alcoholic steatohepatitis (NASH), is considered the primary cause of liver inflammation and fibrosis. However, the mechanisms underlying the regulation of hepatocyte apoptosis in NASH remain largely unclear. We explored the anti-apoptotic effect of hepatocyte CD1d in NASH.

METHODS

Hepatocyte CD1d expression was analyzed in patients with NASH and mouse models. Hepatocyte-specific gene overexpression or knockdown and anti-CD1d crosslinking were used to investigate the anti-apoptotic effect of hepatocyte CD1d on lipotoxicity-, Fas-, and concanavalin (ConA)-mediated liver injuries. A high-fat diet, a methionine-choline-deficient diet, a Fas agonist, and ConA were used to induce lipotoxic and/or apoptotic liver injuries. Palmitic acid was used to mimic lipotoxicity-induced apoptosis in vitro.

RESULTS

We identified a dramatic decrease in CD1d expression in hepatocytes of patients with NASH and mouse models. Hepatocyte-specific CD1d overexpression and knockdown experiments collectively demonstrated that hepatocyte CD1d protected against hepatocyte apoptosis and alleviated hepatic inflammation and injuries in NASH mice. Furthermore, decreased JAK2-STAT3 signaling was observed in NASH patient livers. Mechanistically, anti-CD1d crosslinking on hepatocytes induced tyrosine phosphorylation of the CD1d cytoplasmic tail, leading to the recruitment and phosphorylation of JAK2. Phosphorylated JAK2 activated STAT3 and subsequently reduced apoptosis in hepatocytes, which was associated with an increase in anti-apoptotic effectors (Bcl-xL and Mcl-1) and a decrease in pro-apoptotic effectors (cleaved-caspase 3/7). Moreover, anti-CD1d crosslinking effectively protected against Fas- or ConA-mediated hepatocyte apoptosis and liver injury in mice.

CONCLUSIONS

Our study uncovered a previously unrecognized anti-apoptotic CD1d-JAK2-STAT3 axis in hepatocytes that conferred hepatoprotection and highlighted the potential of hepatocyte CD1d-directed therapy for liver injury and fibrosis in NASH, as well as in other liver diseases associated with hepatocyte apoptosis.

IMPACT AND IMPLICATIONS

Excessive and/or sustained hepatocyte apoptosis is critical in driving liver inflammation and injury. The mechanisms underlying the regulation of hepatocyte apoptosis in non-alcoholic steatohepatitis (NASH) remain largely unclear. Here, we found that CD1d expression in hepatocytes substantially decreases and negatively correlates with the severity of liver injury in patients with NASH. We further revealed a previously unrecognized anti-apoptotic CD1d-JAK2-STAT3 signaling axis in hepatocytes, which confers significant protection against liver injury in NASH and acute liver diseases. Thus, hepatocyte CD1d-targeted therapy could be a promising strategy to manipulate liver injury in both NASH and other hepatocyte apoptosis-related liver diseases.

Caspase-3 Levels Alter With Non-surgical Periodontal Therapy in Patients With Periodontitis

Background This study aims to evaluate the levels of caspase-3 in the gingival crevicular fluid (GCF) of chronic periodontitis patients before and after phase I treatment and compare it with those of healthy controls. Methodology The study involved 40 participants who were divided into two groups. Group 1 consisted of 30 chronic periodontitis patients, and group 2 consisted of 10 healthy controls. GCF was collected at baseline for both groups and at three months for group 1. Periodontal parameters and caspase-3 levels were analyzed before and after non-surgical therapy. Results Caspase-3 levels were higher in patients with chronic periodontitis compared with healthy controls. However, comparing baseline and postoperative levels, there was a statistically significant reduction in periodontal parameters and caspase-3 levels, with 0.80 ± 0.03 at baseline and 0.44 ± 0.02 at three months after non-surgical periodontal therapy. Conclusions Caspase-3, being the key molecule in apoptosis, was found to be at lower concentrations in healthy gingiva and was increased in the presence of periodontal disease. However, with non-surgical periodontal therapy, caspase-3 levels decreased, proving that non-surgical periodontal therapy affects host immune mechanisms and reduces apoptosis, thereby preventing disease progression.

Pathological phenotypes of astrocytes in Alzheimer's disease

Astrocytes are involved in various processes in the central nervous system (CNS). As the most abundant cell type in the CNS, astrocytes play an essential role in neuronal maintenance and support, synaptic activity, neuronal metabolism, and amyloid-beta (Aβ) clearance. Alzheimer's disease (AD) is a neurodegenerative disorder associated with cognitive and behavioral impairment. The transformation of astrocytes is involved in various neurodegenerative diseases, such as AD. Since astrocytes have functional diversity and morphological and physiological heterogeneity in the CNS, AD-related astrocytes might show various pathological phenotypes during AD. Astrocytes developing pathological phenotypes could contribute to AD progression. In this review, we provide an overview of the pathological phenotypes of astrocytes in the context of AD, highlighting recent findings in human and mouse AD.

Bioprocessing of Epothilone B from Aspergillus fumigatus under solid state fermentation: Antiproliferative activity, tubulin polymerization and cell cycle analysis

Epothilone derivatives have been recognized as one of the most powerful anticancer drugs towards solid tumors, for their unique affinity to bind with β-tubulin microtubule arrays, stabilizing their disassembly, causing cell death. Sornagium cellulosum is the main source for Epothilone, however, the fermentation bioprocessing of this myxobacteria is the main challenge for commercial production of Epothilone. The metabolic biosynthetic potency of epothilone by Aspergillus fumigatus, an endophyte of Catharanthus roseus, raises the hope for commercial epothilone production, for their fast growth rate and feasibility of manipulating their secondary metabolites. Thus, nutritional optimization of A. fumigatus for maximizing their epothilone productivity under solid state fermentation process is the objective. The highest yield of epothilone was obtained by growing A. fumigatus on orange peels under solid state fermentation (2.2 μg/g), bioprocessed by the Plackett-Burman design. The chemical structure of the extracted epothilone was resolved from the HPLC and LC-MS/MS analysis, with molecular mass 507.2 m/z and identical molecular fragmentation pattern of epothilone B of S. cellulosum. The purified A. fumigatus epothilone had a significant activity towards HepG2 (IC50 0.98 μg/ml), Pancl (IC50 1.5 μg/ml), MCF7 (IC50 3.7 μg/ml) and WI38 (IC50 4.6 μg/ml), as well as a strong anti-tubulin polymerization activity (IC50 0.52 μg/ml) compared to Paclitaxel (2.0 μg/ml). The effect of A. fumigatus epothilone on the immigration ability of HepG2 cells was assessed, as revealed from the wound closure of the monolayer cells that was estimated by ~ 63.7 and 72.5%, in response to the sample and doxorubicin, respectively, compared to negative control. From the Annexin V-PI flow cytometry results, a significant shift of the normal cells to the apoptosis was observed in response to A. fumigatus epothilone by ~ 20 folds compared to control cells, with the highest growth arrest of the HepG2 cells at the G0-G1 stage.

Activation of caspase-9 on the apoptosome as studied by methyl-TROSY NMR

Mitochondrial apoptotic signaling cascades lead to the formation of the apoptosome, a 1.1-MDa heptameric protein scaffold that recruits and activates the caspase-9 protease. Once activated, caspase-9 cleaves and activates downstream effector caspases, triggering the onset of cell death through caspase-mediated proteolysis of cellular proteins. Failure to activate caspase-9 enables the evasion of programmed cell death, which occurs in various forms of cancer. Despite the critical apoptotic function of caspase-9, the structural mechanism by which it is activated on the apoptosome has remained elusive. Here, we used a combination of methyl-transverse relaxation-optimized NMR spectroscopy, protein engineering, and biochemical assays to study the activation of caspase-9 bound to the apoptosome. In the absence of peptide substrate, we observed that both caspase-9 and its isolated protease domain (PD) only very weakly dimerize with dissociation constants in the millimolar range. Methyl-NMR spectra of isotope-labeled caspase-9, within the 1.3-MDa native apoptosome complex or an engineered 480-kDa apoptosome mimic, reveal that the caspase-9 PD remains monomeric after recruitment to the scaffold. Binding to the apoptosome, therefore, organizes caspase-9 PDs so that they can rapidly and extensively dimerize only when substrate is present, providing an important layer in the regulation of caspase-9 activation. Our work highlights the unique role of NMR spectroscopy to structurally characterize protein domains that are flexibly tethered to large scaffolds, even in cases where the molecular targets are in excess of 1 MDa, as in the present example.

Perish in the Attempt: Regulated Cell Death in Regenerative and Nonregenerative Tissue

Significance: A cell plays its roles throughout its life span, even during its demise. Regulated cell death (RCD) is one of the key topics in modern biomedical studies. It is considered the main approach for removing stressed and/or damaged cells. Research during the past two decades revealed more roles of RCD, such as coordinating tissue development and driving compensatory proliferation during tissue repair. Recent Advances: Compensatory proliferation, initially identified in primitive organisms during the regeneration of lost tissue, is an evolutionarily conserved process that also functions in mammals. Among various types of RCD, apoptosis is considered the top candidate to induce compensatory proliferation in damaged tissue. Critical Issues: The roles of apoptosis in the recovery of nonregenerative tissue are still vague. The roles of other types of RCD, such as necroptosis and ferroptosis, have not been well characterized in the context of tissue regeneration. Future Directions: In this review article, we attempt to summarize the recent insights on the role of RCD in tissue repair. We focus on apoptosis, with expansion to ferroptosis and necroptosis, in primitive organisms with significant regenerative capacity as well as common mammalian research models. After gathering hints from regenerative tissue, in the second half of the review, we take a notoriously nonregenerative tissue, the myocardium, as an example to discuss the role of RCD in terminally differentiated quiescent cells. Antioxid. Redox Signal. 39, 1053-1069.

Chloro-substituted pyridine squaramates as new DNase I inhibitors: Synthesis, structural characterization, in vitro evaluation and molecular docking studies

Having continued our recent study on the synthesis and DNase I inhibition of several monosquaramides, two new chloro-substituted pyridine squaramates were synthesized and their structure was identified by X-ray. Their inhibitory properties towards deoxyribonuclease I (DNase I) and xanthine oxidase (XO) were evaluated in vitro. 3-(((6-Chloropyridin-3-yl)methyl)amino)-4-ethoxycyclobut-3-ene-1,2-dione (compound 3a) inhibited DNase I with an IC50 value of 43.82 ± 6.51 μM, thus standing out as one of the most potent small organic DNase I inhibitors tested to date. No cytotoxicity to human tumor cell lines (HL-60, MDA-MB-231 and MCF-7) was observed for the tested compounds. In order to investigate the drug-likeness of the squaramates, the ADME profile and pharmacokinetic properties were evaluated. Molecular docking was performed to reveal the binding mode of the studied compounds on DNase I.

Nanomedicine-mediated regulated cell death in cancer immunotherapy

Immunotherapy has attracted widespread attention in cancer treatment and has achieved considerable success in the clinical treatment of some tumors, but it has a low response rate in most tumors. To achieve sufficient activation of the immune response, significant efforts using nanotechnology have been made to enhance cancer immune response. In recent years, the induction of various regulated cell death (RCD) has emerged as a potential antitumor immuno-strategy, including processes related to apoptosis, autophagy, necroptosis, pyroptosis, ferroptosis, and cuproptosis. In particular, damage-associated molecular patterns (DAMPs) released from the damaged membrane of dying cells act as in situ adjuvants to trigger antigen-specific immune responses by the exposure of an increased antigenicity. Thus, RCD-based immunotherapy offers a new approach for enhancing cancer treatment efficacy. Furthermore, incorporation with multimodal auxiliary therapies in cell death-based immunotherapy can trigger stronger immune responses, resulting in more efficient therapeutic outcome. This review discusses different RCD modalities and summarizes recent nanotechnology-mediated RCDs in cancer immunotherapy.

Recent Updates in Venetoclax Combination Therapies in Pediatric Hematological Malignancies

Venetoclax is a strongly effective B-cell lymphoma-2 inhibitor (BCL-2) with an ability to selectively restore the apoptotic potential of cancerous cells. It has been proven that in combination with immunotherapy, targeted therapies, and lower-intensity therapies such as hypomethylating agents (HMAs) or low-dose cytarabine (LDAC), the drug can improve overall outcomes for adult patients with acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), and multiple myeloma (MM), amongst other hematological malignancies, but its benefit in pediatric hematology remains unclear. With a number of preclinical and clinical trials emerging, the newest findings suggest that in many cases of younger patients, venetoclax combination treatment can be well-tolerated, with a safety profile similar to that in adults, despite often leading to severe infections. Studies aim to determine the activity of BCL-2 inhibitor in the treatment of both primary and refractory acute leukemias in combination with standard and high-dose chemotherapy. Although more research is required to identify the optimal venetoclax-based regimen for the pediatric population and its long-term effects on patients' outcomes, it can become a potential therapeutic agent for pediatric oncology.

Apical extrusion prevents apoptosis from activating an acute inflammatory program in epithelia

Apoptosis is traditionally considered to be an immunologically silent form of cell death. Multiple mechanisms exist to ensure that apoptosis does not stimulate the immune system to cause inflammation or autoimmunity. Against this expectation, we now report that epithelia are programmed to provoke, rather than suppress, inflammation in response to apoptosis. We found that an acute inflammatory response led by neutrophils occurs in zebrafish and cell culture when apoptotic epithelial cells cannot be expelled from the monolayer by apical extrusion. This reflects an intrinsic circuit where ATP released from apoptotic cells stimulates epithelial cells in the immediate vicinity to produce interleukin-8 (IL-8). Apical extrusion therefore prevents inappropriate epithelial inflammation by physically eliminating apoptotic cells before they can activate this pro-inflammatory circuit. This carries the implication that epithelia may be predisposed to inflammation, elicited by sporadic or induced apoptosis, if apical extrusion is compromised.

A biocompatible pure organic porous nanocage for enhanced photodynamic therapy

Porphyrin-based photosensitizers have been widely utilized in photodynamic therapy (PDT), but they suffer from deteriorating fluorescence and reactive oxygen species (ROS) due to their close π-π stacking. Herein, a biocompatible pure organic porphyrin nanocage (Py-Cage) with enhanced both type I and type II ROS generation is reported for PDT. The porphyrin skeleton within the Py-Cage is spatially separated by four biphenyls to avoid the close π-π stacking within the nanocage. The Py-Cage showed a large cavity and high porosity with a Brunauer-Emmett-Teller surface area of over 300 m2 g-1, facilitating a close contact between the Py-Cage and oxygen, as well as the fast release of ROS to the surrounding microenvironment. The Py-Cage shows superb ROS generation performance over its precursors and commercial ones such as Chlorin E6 and Rose Bengal. Intriguingly, the cationic π-conjugated Py-Cage also shows promising type I ROS (superoxide and hydroxyl radicals) generation that is more promising for hypoxic tumor treatment. Both in vitro cell and in vivo animal experiments further confirm the excellent antitumor activity of the Py-Cage. As compared to conventional metal coordination approaches to improve PDT efficacy of porphyrin derivatives, the pure organic porous Py-Cage demonstrates excellent biocompatibility, which is further verified in both mice and rats. This work of an organic porous nanocage shall provide a new paradigm for the design of novel, biocompatible and effective photosensitizers for PDT.

Identification of Potential Genes and Critical Pathways in Postoperative Recurrence of Crohn's Disease by Machine Learning And WGCNA Network Analysis

Background

Crohn's disease (CD) is a chronic idiopathic inflammatory bowel disease affecting the entire gastrointestinal tract from the mouth to the anus. These patients often experience a period of symptomatic relapse and remission. A 20 - 30% symptomatic recurrence rate is reported in the first year after surgery, with a 10% increase each subsequent year. Thus, surgery is done only to relieve symptoms and not for the complete cure of the disease. The determinants and the genetic factors of this disease recurrence are also not well-defined. Therefore, enhanced diagnostic efficiency and prognostic outcome are critical for confronting CD recurrence.

Methods

We analysed ileal mucosa samples collected from neo-terminal ileum six months after surgery (M6=121 samples) from Crohn's disease dataset (GSE186582). The primary aim of this study is to identify the potential genes and critical pathways in post-operative recurrence of Crohn's disease. We combined the differential gene expression analysis with Recursive feature elimination (RFE), a machine learning approach to get five critical genes for the postoperative recurrence of Crohn's disease. The features (genes) selected by different methods were validated using five binary classifiers for recurrence and remission samples: Logistic Regression (LR), Decision tree classifier (DT), Support Vector Machine (SVM), Random Forest classifier (RF), and K-nearest neighbor (KNN) with 10-fold cross-validation. We also performed weighted gene co-expression network analysis (WGCNA) to select specific modules and feature genes associated with Crohn's disease postoperative recurrence, smoking, and biological sex. Combined with other biological interpretations, including Gene Ontology (GO) analysis, pathway enrichment, and protein-protein interaction (PPI) network analysis, our current study sheds light on the in-depth research of CD diagnosis and prognosis in postoperative recurrence.

Results

PLOD2, ZNF165, BOK, CX3CR1, and ARMCX4, are the important genes identified from the machine learning approach. These genes are reported to be involved in the viral protein interaction with cytokine and cytokine receptors, lysine degradation, and apoptosis. They are also linked with various cellular and molecular functions such as Peptidyl-lysine hydroxylation, Central nervous system maturation, G protein-coupled chemoattractant receptor activity, BCL-2 homology (BH) domain binding, Gliogenesis and negative regulation of mitochondrial depolarization. WGCNA identified a gene co-expression module that was primarily involved in mitochondrial translational elongation, mitochondrial translational termination, mitochondrial translation, mitochondrial respiratory chain complex, mRNA splicing via spliceosome pathways, etc.; Both the analysis result emphasizes that the mitochondrial depolarization pathway is linked with CD recurrence leading to oxidative stress in promoting inflammation in CD patients.

Conclusion

These key genes serve as the novel diagnostic biomarker for the postoperative recurrence of Crohn's disease. Thus, among other treatment options present until now, these biomarkers would provide success in both diagnosis and prognosis, aiming for a long-lasting remission to prevent further complications in CD.

A novel antibody-KSP inhibitor conjugate improves KSP inhibitor efficacy in vitro and in vivo

Many clinical trials of kinesin spindle protein (KSP) inhibitors have failed due to issues such as high toxicity and a short circulation half-life in vivo. To address the limitations of current KSP inhibitors and thus broad its use in antitumor therapy, this study applied antibody-drug conjugate (ADC) technology to the KSP inhibitor SB-743921, which was coupled with the HER2-specific antibody trastuzumab using a cathepsin B-dependent valine-alanine (Val-Ala, VA) dipeptide-type linker to generate H2-921. Ex vivo and in vivo analyses of H2-921 showed an increased half-life of SB-743921 and prolonged contact time with tumor cells. Furthermore, H2-921 induced apoptosis and incomplete autophagy in HER2-positive cells. In the in vivo analyses, H2-921 had significant tumor-targeting properties, and tumor inhibition by H2-921 was greater than that by traditional KSP inhibitors but similar to that by the positive control drug T-DM1. In conclusion, this study describes a novel application of ADC technology that enhances the antitumor effects of a KSP inhibitor and thus may effectively address the poor clinical efficacy of KSP inhibitors.

Understanding IP3R channels: From structural underpinnings to ligand-dependent conformational landscape

Inositol 1,4,5-trisphosphate receptors (IP3Rs) are ubiquitously expressed large-conductance Ca2+-permeable channels predominantly localized to the endoplasmic reticulum (ER) membranes of virtually all eukaryotic cell types. IP3Rs work as Ca2+ signaling hubs through which diverse extracellular stimuli and intracellular inputs are processed and then integrated to result in delivery of Ca2+ from the ER lumen to generate cytosolic Ca2+ signals with precise temporal and spatial properties. IP3R-mediated Ca2+ signals control a vast repertoire of cellular functions ranging from gene transcription and secretion to the more enigmatic brain activities such as learning and memory. IP3Rs open and release Ca2+ when they bind both IP3 and Ca2+, the primary channel agonists. Despite overwhelming evidence supporting functional interplay between IP3 and Ca2+ in activation and inhibition of IP3Rs, the mechanistic understanding of how IP3R channels convey their gating through the interplay of two primary agonists remains one of the major puzzles in the field. The last decade has seen much progress in the use of cryogenic electron microscopy to elucidate the molecular mechanisms of ligand binding, ion permeation, ion selectivity and gating of the IP3R channels. The results of these studies, summarized in this review, provide a prospective view of what the future holds in structural and functional research of IP3Rs.

Androgens Modulate Bcl-2 Agonist of Cell Death (BAD) Expression and Function in Breast Cancer Cells

Androgen receptor (AR) expression in estrogen receptor-positive (ER+) breast cancer (BC) correlates with lower tumor grade and a better clinical outcome. Additionally, in normal mammary epithelium or ER+ BC preclinical models, androgens counteract basal/ER-dependent proliferation. Here, we report an additional mechanism, underlining the protective role exerted by AR. Specifically, the activation of intracellular AR upregulates the Bcl-2-family protein BAD, and TCGA database analyses show that in ER+ BC, BAD expression is associated with better disease-free survival. Ligand-activated AR influences its own and BAD cellular compartmentalization by enhancing levels in the nucleus, as well as in mitochondrial fractions. In both compartments, BAD exerts unconventional functions. In the nucleus, BAD and AR physically interact and, upon androgen stimulation, are recruited at the AP-1 and ARE sites within the cyclin D1 promoter region, contributing to explaining the anti-proliferative effect of androgens in BC cells. Androgens cause an enrichment in BAD and AR content in the mitochondria, correlated with a decrease in mitochondrial function. Thus, we have defined a novel mechanism by which androgens modulate BAD expression, its mitochondria localization, and nuclear content to force its ability to act as a cell cycle inhibitor, strengthening the protective role of androgen signaling in estrogen-responsive BCs.

Diversity and complexity of cell death: a historical review

Death is the inevitable fate of all living organisms, whether at the individual or cellular level. For a long time, cell death was believed to be an undesirable but unavoidable final outcome of nonfunctioning cells, as inflammation was inevitably triggered in response to damage. However, experimental evidence accumulated over the past few decades has revealed different types of cell death that are genetically programmed to eliminate unnecessary or severely damaged cells that may damage surrounding tissues. Several types of cell death, including apoptosis, necrosis, autophagic cell death, and lysosomal cell death, which are classified as programmed cell death, and pyroptosis, necroptosis, and NETosis, which are classified as inflammatory cell death, have been described over the years. Recently, several novel forms of cell death, namely, mitoptosis, paraptosis, immunogenic cell death, entosis, methuosis, parthanatos, ferroptosis, autosis, alkaliptosis, oxeiptosis, cuproptosis, and erebosis, have been discovered and advanced our understanding of cell death and its complexity. In this review, we provide a historical overview of the discovery and characterization of different forms of cell death and highlight their diversity and complexity. We also briefly discuss the regulatory mechanisms underlying each type of cell death and the implications of cell death in various physiological and pathological contexts. This review provides a comprehensive understanding of different mechanisms of cell death that can be leveraged to develop novel therapeutic strategies for various diseases.

Identification of reactive oxygen species that induce spoptosis, a novel and distinctive mode of regulated cell death

Using some solutions activated by irradiation with non-thermal atmospheric pressure plasma (NTAPP), we had discovered that a new and distinctive mode of cell death, named spoptosis, exists in cells, the induction of which involves the action of reactive oxygen species (ROS). However, it was unknown what types of ROS and how they trigger the cell death. When cells were treated with a higher dose of Ascorbic acid (AA) generating O₂^- and H₂O₂ or Antimycin A (AM) generating O₂^-, cell death occurred along with cellular shrinkage, Pdcd4 disappearance, and vesicle formation. Only in cells treated with AA, genomic DNA was digested irregularly and membrane permeability increased aberrantly. On the other hand, cells treated with a higher dose of H₂O₂ displayed cell death and cellular shrinkage but not the other events, and those treated with a lower dose of H₂O₂ displayed cell death but not the other events. Strikingly, when cells underwent double treatment with AM and H₂O₂, the events, which had not been observed by their single treatment, became compensated. All the events were suppressed with an antioxidant, confirming that they were mediated by ROS. Thus, the mode of cell death induced by AA or combination of AM and H₂O₂ was consistent with that of cell death by NTAPP-activated solutions. These results suggested that O₂^- and H₂O₂ collaboratively trigger spoptotic cell death with the associated events, and that AA and combination of AM and H₂O₂ are functionally alternative in place of NTAPP-activated solutions.

Wg/Wnt1 and Erasp link ER stress to proapoptotic signaling in an autosomal dominant retinitis pigmentosa model

The endoplasmic reticulum (ER) is a subcellular organelle essential for cellular homeostasis. Perturbation of ER functions due to various conditions can induce apoptosis. Chronic ER stress has been implicated in a wide range of diseases, including autosomal dominant retinitis pigmentosa (ADRP), which is characterized by age-dependent retinal degeneration caused by mutant rhodopsin alleles. However, the signaling pathways that mediate apoptosis in response to ER stress remain poorly understood. In this study, we performed an unbiased in vivo RNAi screen with a Drosophila ADRP model and found that Wg/Wnt1 mediated apoptosis. Subsequent transcriptome analysis revealed that ER stress-associated serine protease (Erasp), which has been predicted to show serine-type endopeptidase activity, was a downstream target of Wg/Wnt1 during ER stress. Furthermore, knocking down Erasp via RNAi suppressed apoptosis induced by mutant rhodopsin-1 (Rh-1P37H) toxicity, alleviating retinal degeneration in the Drosophila ADRP model. In contrast, overexpression of Erasp resulted in enhanced caspase activity in Drosophila S2 cells treated with apoptotic inducers and the stabilization of the initiator caspase Dronc (Death regulator Nedd2-like caspase) by stimulating DIAP1 (Drosophila inhibitor of apoptosis protein 1) degradation. These findings helped identify a novel cell death signaling pathway involved in retinal degeneration in an autosomal dominant retinitis pigmentosa model.