Induced Cell Death Research Articles

Short-term airborne ultrasound induced cell death in tobacco cells and changed their wall components

The effects of low-intensity ultrasound on plants such as piezoelectric and ultrasonic water baths, on plants have been extensively studied. However, the specific effect of airborne ultrasound on plant cells has yet to be reported. The present study was conducted to elucidate the physiological responses of plant cells to airborne US. Homogeneous suspension-cultured tobacco cells (Nicotiana tabacum L. cv Burley 21) were subjected to airborne US at 24 kHz in two pulsatile and continuous modes for 10 and 20 s. The study’s outcome revealed that airborne US triggered the production of H2O2, elevated internal calcium concentration, and reduced antioxidant capacity upon cavitation. Alteration of covalently bound peroxidase and other wall-modifying enzyme activities was accompanied by reduced cellulose, pectin, and hemicellulose B but increased lignin and hemicellulose A. The biomass and viability of tobacco cells were also significantly decreased by airborne US, which ultimately resulting in PCD and secondary necrosis. The results highlight the potential risks of even short-time exposure to the airborne US on plant physiology and cell wall chemical composition raising significant concerns about its implications.

Abstract A013: Shikonin, a strong inhibitor of Phosphoinositide 3-Kinase (PI3K) and Mitogen-Activated Protein (MAP) Kinase pathways, induces cell death in UV-B irradiated B16F10 melanoma cells

Abstract Ultraviolet (UV) radiation-induced skin damage plays a pivotal role in the pathogenesis of melanoma, a highly aggressive and fatal form of skin cancer. Shikonin, naturally occurring nathoquinone , is well-known for its inhibitory effects on phosphoinositide 3-kinase (PI3K) and mitogen-activated protein (MAP) kinase signaling pathways. It has previously been demonstrated to exert effects against various non-melanoma skin cancers. In this study, we investigated the effects of Shikonin treatment on UVB-irradiated B16F10 melanoma cells, revealing a dose-dependent reduction in cell viability and an enhancement of apoptosis. Invitro findings indicate that the pro-apoptotic effects of shikonin in UVB-exposed B16F10 cells are mediated by several mechanisms, including the generation of reactive oxygen species (ROS), modulation of the antioxidant defense response, and mitochondrial membrane potential (ΔΨM) depolarization. Further supporting the apoptotic role of Shikonin, we observed DNA fragmentation, caspase activation, poly(ADP-ribose) polymerase (PARP) cleavage, and an increase in sub-G2 cell populations. Shikonin treatment also significantly attenuated MEK-ERK signaling, influenced the PI3K/Akt pathway, and potentially inhibited UVB-induced nuclear translocation of NF-κB. Additionally, co-treatment with UVB and Shikonin led to a decrease in the Bcl-2/Bax ratio and upregulated the expression of pro-apoptotic proteins Bax and caspases. Collectively, these data suggest that Shikonin may act as a potential therapeutic agent for melanoma when combined with UVB exposure, providing a novel avenue for future treatment strategies. Citation Format: Aalim Maqsood Bhat, Sheikh Tasduq Abdullah. Shikonin, a strong inhibitor of Phosphoinositide 3-Kinase (PI3K) and Mitogen-Activated Protein (MAP) Kinase pathways, induces cell death in UV-B irradiated B16F10 melanoma cells. [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Targeted Therapies in Combination with Radiotherapy; 2025 Jan 26-29; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(2_Suppl):Abstract nr A013.

Histone deacetylases in the regulation of cell death and survival mechanisms in resistant BRAF-mutant cancers

Small-molecule BRAF inhibitors (e.g., vemurafenib and dabrafenib) and MEK (MAPK/ERK) kinases inhibitors (e.g., trametinib) have distinctly improved the survival of patients suffering from BRAF-mutant cancers such as melanomas. However, the emergence of resistance to BRAF and MEK inhibitor-based melanoma therapy, as well as the reduced sensitivity of other BRAF-mutant cancers such as CRC, poses a considerable clinical problem. For instance, the reactivation of MAPK/ERK signaling hampering cell death induction mechanisms was responsible for BRAF inhibitor resistance, which can be correlated with distinct post-translational and epigenetic processes. Histone deacetylases (HDACs) are prominent epigenetic drug targets and some HDAC inhibitors have already been clinically approved for the therapy of various blood cancers. In addition, several HDACs were identified, which also play a crucial role in the drug resistance of BRAF-mutant cancers. Consequently, inhibition of HDACs was described as a promising approach to overcome resistance. This review summarizes the influence of HDACs (Zn2+-dependent HDACs and NAD+-dependent sirtuins) on BRAF-mutant cancers and BRAF inhibitor resistance based on upregulated survival mechanisms and the prevention of tumor cell death. Moreover, it outlines reasonable HDAC-based strategies to circumvent BRAF-associated resistance mechanisms based on downregulated cell death mechanisms.

Ailanthone induces triple-negative breast cancer cells death involving the inhibition of OTUB1-mediated ERRα deubiquitylation.

Triple-negative breast cancer (TNBC) remains the most aggressive subtype of breast cancer, and effective therapeutic strategies are needed. Estrogen-related receptor alpha (ERRα) is considered a promising target for managing TNBC. Here, we aimed to screen natural products to find downregulator of ERRα and elucidate its mechanism of action. TNBC cells (MDA-MB-231, MDA-MB-468, MDA-MB-453, and BT-549) were used for in vitro studies, and a subcutaneous MDA-MB-231 tumor model was created for in vivo studies. Immunofluorescence assessed protein distribution, while competitive activity-based protein profiling identified potential target proteins. Co-immunoprecipitation detected protein interactions and modifications, and a luciferase reporter assay evaluated ERRα transcriptional activity. The natural product Ailanthone (AIL) effectively induced cell death in TNBC cells by reducing the protein level of ERRα. The mechanism of action involved AIL promoting the degradation of ERRα through the ubiquitin-proteasome system, consequently reducing its transcriptional activity. The competitive-ABPP method mapped the profile of target proteins for AIL, and OTU domain-containing ubiquitin aldehyde-binding protein 1 (OTUB1) was identified as a pivotal target of AIL in regulating ERRα protein levels. OTUB1 was validated as a novel deubiquitinating enzyme for ERRα, with its C91 residue being crucial for this deubiquitination process. AIL was found to inhibit the enzyme activity of OTUB1 by interacting with the C91 residue and disrupt the interaction between OTUB1 and ERRα, ultimately leading to the inhibition of ERRα. AIL is a promising downregulator of ERRα, and the mechanism of this downregulation has been elucidated. Additionally, a new regulatory relationship between ERRα and OTUB1 is identified. The research presented in this article is anticipated to yield potential lead compounds for ERRα regulatory agents and to stimulate the development of novel therapeutic strategies designed to modulate ERRα activity for the treatment of TNBC.

Synthesis, Anticancer Screening, and In Silico Evaluations of Thieno[2,3-c]pyridine Derivatives as Hsp90 Inhibitors

Background: Thieno[2,3-c]pyridines and their analogs are not well explored for their anticancer properties. Hence, our research aimed to establish the anticancer potential of thieno[2,3-c]pyridines through cell-based assays and in silico evaluations. Methods: Thieno[2,3-c]pyridine derivatives 6(a–k) were synthesized and characterized using FT-IR, 1H-NMR, 13C-NMR, and HRMS. All the synthesized compounds were screened initially for their anticancer activity against MCF7 and T47D (breast cancer), HSC3 (head and neck cancer), and RKO (colorectal cancer) cell lines using MTT assay. Apoptosis and cell cycle analyses were conducted using Annexin V/propidium iodide (PI) double staining for apoptosis assessment and PI staining for cell cycle analysis to investigate the mechanisms underlying the reduced cell viability. In silico molecular docking was accomplished for the synthesized compounds against the Hsp90 and determined pharmacokinetics properties. Results: From the screening assay, compounds 6a and 6i were identified as potential inhibitors and were further subjected to IC50 determination. The compound 6i showed potent inhibition against HSC3 (IC50 = 10.8 µM), T47D (IC50 = 11.7 µM), and RKO (IC50 = 12.4 µM) cell lines, all of which indicated a broad spectrum of anticancer activity. Notably, 6i was found to induce G2 phase arrest, thereby inhibiting cell cycle progression. Molecular docking results indicated crucial molecular interactions of the synthesized ligands against the target Hsp90. Conclusion: The compound 6i induced cell death via mechanisms that are different from apoptosis. Thus, the synthesized thieno[2,3-c]pyridine derivatives can be suitable lead compounds to be optimized to obtain potent anticancer agents through Hsp90 inhibition.

Calcium hydroxide nanoparticles induce cell death, genomic instability, oxidative stress and apoptotic gene dysregulation on human HepG2 cells

Calcium hydroxide nanoparticles (Ca(OH)2NPs) possess potent antimicrobial activities and unique physical and chemical properties, making them valuable across various fields. However, limited information exists regarding their effects on genomic DNA integrity and their potential to induce apoptosis in normal and cancerous human cell lines. This study thus aimed to evaluate the impact of Ca(OH)2NPs on cell viability, genomic DNA integrity, and oxidative stress induction in human normal skin fibroblasts (HSF) and cancerous hepatic (HepG2) cells. Cell viability and genomic DNA stability were assessed using the Sulforhodamine B (SRB) assay and alkaline comet assay, respectively. Reactive oxygen species (ROS) levels were measured using 2,7-dichlorofluorescein diacetate, while the expression level of apoptosis-related genes (p53, Bax, and Bcl-2) were quantified using real-time PCR (qRT-PCR). The SRB cytotoxicity assay revealed that a 48-hour exposure to Ca(OH)2NPs caused concentration-dependent cell death and proliferation inhibition in both HSF and HepG2 cells, with IC50 values of 271.93 µg/mL for HSF and 291.8 µg/mL for HepG2 cells. Treatment with the IC50 concentration of Ca(OH)2NPs selectively induced significant DNA damage, excessive ROS generation, and marked dysregulation of apoptotic (p53 and Bax) and anti-apoptotic (Bcl-2) gene expression in HepG2 cells, triggering apoptosis. In contrast, exposure of HSF cells to the IC50 concentration of Ca(OH)2NPs caused no significant changes in genomic DNA integrity, ROS generation, or apoptotic gene expression. These findings indicate that Ca(OH)2NPs exhibit concentration-dependent cytotoxicity in both normal HSF and cancerous HepG2 cells. However, exposure to the IC50 concentration was non-genotoxic to normal HSF cells while selectively inducing genotoxicity and apoptosis in HepG2 cancer cells through DNA breaks and ROS-mediated mechanisms. Further studies are required to explore the biological and toxicological properties and therapeutic potential of Ca(OH)2NPs in hepatic cancer treatment.

Corrigendum: Anticancer effects of ABTL0812, a clinical stage drug inducer of autophagy-mediated cancer cell death, in glioblastoma models

Corrigendum: Anticancer effects of ABTL0812, a clinical stage drug inducer of autophagy-mediated cancer cell death, in glioblastoma models

DOP109 A necroptotic-to-apoptotic signaling axis underlies inflammatory bowel disease

Abstract Background Dysregulated programmed cell death plays a key role in IBD pathogenesis, with clinical trials exploring anti-necroptotic therapies (1,2). While apoptosis and necroptosis are well-studied in murine colitis models, their prevalence, mechanisms, and therapeutic relevance in human IBD remains unclear. We examined cell death pathways in patients on advanced therapies, uncovering unique signalling mechanisms that could inform future treatments. Methods Over 900 paired intestinal biopsies were analysed from 52 IBD patients (25 Crohn’s disease, 27 ulcerative colitis) and 28 non-IBD controls. Biopsies were taken from inflamed, marginal, and non-inflamed areas. Cell death processes, including apoptosis (e.g. cleaved caspase-3) and necroptosis (e.g. RIPK3, MLKL), were assessed using histology, immunoblotting and RNA sequencing. The effects of IBD-associated inflammatory cytokines (TNF, IFNγ) on epithelial death were tested on human-derived intestinal organoids(Fig 1). Data was correlated with clinical parameters like disease indices and treatments, with tissue quality validated using S100A8/S100A9 expression and blinded histology scoring. Results Increased necroptotic and apoptotic signalling were prominent in IBD, correlating with intestinal inflammation, regardless of treatment. Necroptotic signalling was detected in non-inflamed IBD tissue, suggesting early activation in disease progression, while apoptotic signalling was primarily in inflamed tissue. Gene set enrichment analysis identified dysregulated TNF and IFNγ-related pathways linked to cell death signalling, exacerbated by inflammation. Bulk RNA sequencing demonstrated that inflammation-induced transcriptional reprogramming of epithelial cells triggered a macrophage-like phenotype, promoting RIPK1-independent necroptotic signalling(Fig1). In vitro, exposure to TNF and IFNγ in intestinal organoids synergistically induced cell death, primarily through mitochondrial apoptosis. IFNγ enhanced epithelial cell reprogramming, amplifying cell death signalling, while both cytokines together induced mitochondrial apoptosis. In intestinal stem cells, apoptosis was driven by increased PUMA, while upregulated iNOS expression mediated epithelial cell death. Conclusion Early IBD inflammation reprograms epithelial cells into a macrophage-like state, promoting RIPK1-independent necroptotic signalling. IFNγ and TNF synergise to induce iNOS- and PUMA-mediated mitochondrial apoptosis in epithelial and stem cells. This aberrant epithelial cell death signalling persists despite histologic remission or treatment. Necroptotic signalling occurs upstream of apoptotic cell death, suggesting that targeting the necroptotic-to-apoptotic axis could facilitate molecular healing and sustained deep remission in IBD.

Anticancer diiron aminocarbyne complexes with labile N-donor ligands.

The novel diiron amine complexes [Fe2Cp2(CO)(NH2R')(μ-CO){μ-CN(Me)(Cy)}]CF3SO3 [R'=H, 3; Cy, 4; CH2CH2NH2, 5; CH2CH2NMe2, 6; CH2CH2(4-C6H4OMe), 7; CH2CH2(4-C6H4OH), 8; Cp=η5-C5H5, Cy=C6H11=cyclohexyl] were synthesized in 49-92% yields from [Fe2Cp2(CO)2(μ-CO){μ-CN(Me)(Cy)}]CF3SO3, 1a, using a straightforward two-step procedure. They were characterized by IR and multinuclear NMR spectroscopy, and the structure of 7 was confirmed through X-ray diffraction analysis. Complexes 3-8 and the acetonitrile adducts [Fe2Cp2(CO)(NCMe)(μ-CO){μ-CN(Me)(R)}]CF3SO3 (R = Cy, 2a; Me, 2b; Xyl=2,6-C6H3Me2, 2c) were assessed for their water solubility, octanol-water partition coefficient and stability in physiological-like solutions. The in vitro antiproliferative activity of 2a-c and 3-8 was tested on seven human cancer cell lines (A2780, A2780R, PC3, A549, MCF7, HOS and HT-29), while the selectivity was evaluated using normal MRC-5cells. Overall, the complexes exhibited variable cytotoxicity, with IC50 values reaching the low micromolar range for 3, 7 and 8 in A2780 and A2780R cells, along with significant selectivity. Targeted experiments covered cell cycle modification, induction of cell death, mitochondrial membrane potential, ROS production and interaction with DNA and bovine serum albumin (BSA) as a model protein. The interaction of 3 with BSA was further investigated through computational studies. Results showed a negligible increase in intracellular ROS levels (except for 2b) and insignificant changes in mitochondrial membrane potential.

Assessment of Self-Activation and Inhibition of Wheat Coiled-Coil Domain Containing NLR Immune Receptor Yr10CG.

Plant immunity is largely governed by nucleotide-binding leucine-rich repeat receptor (NLR). Here, we examine the molecular activation and inhibition mechanisms of the wheat CC-type NLR Yr10CG, a previously proposed candidate for the Yr10 resistance gene. Though recent studies have identified YrNAM as the true Yr10 gene, Yr10CG remains an important NLR in understanding NLR-mediated immunity in wheat. In this study, we found that the overexpression of either the full-length Yr10CG or its CC domain in Nicotiana benthamiana did not trigger cell death, suggesting a robust autoinhibitory mechanism within Yr10CG. However, we observed that mutations in the conserved MHD motif, specifically D502G, activated Yr10CG and induced cell death. Structural modeling indicated that this mutation disrupted key interactions within the MHD motif, promoting local flexibility and activation. We further explored the effector recognition potential of Yr10CG by creating chimeric proteins with Sr50 domains, revealing that both the NB-ARC and LRR domains are necessary for effector recognition, while the CC domain likely functions in downstream immune signaling. Additionally, disrupting membrane localization through an L11E mutation abolished Yr10CG self-activation, suggesting a requirement for membrane association in immune activation. Our findings contribute to the understanding of CC-NLR activation and autoinhibition mechanisms, highlighting the potential of Yr10CG in NLR engineering for crop resistance improvement.

Two-Step Cell Death Induction by the New 2-Arachidonoyl Glycerol Analog and Its Modulation by Lysophosphatidylinositol in Human Breast Cancer Cells.

2-arachnadoyl glycerol (2-AG) is one of the most common endocannabinoid molecules with anti-proliferative, cytotoxic, and pro-proliferative effects on different types of tumors. Typically, it induces cell death via cannabinoid receptor 1/2 (CB1/CB2)-linked ceramide production. In breast cancer, ceramide is counterbalanced by the sphingosine-1-phosphate, and thus the mechanisms of 2-AG influence on proliferation are poorly understood. We evaluated the mechanism of the anti-proliferative action by 2-AG and the influence of lysophaosphatidylinositol (LPI) on it in six human breast cancer cell lines of different tumor degree (MCF-10A, MCF-7, BT-474, BT-20, SK-BR-3, and MDA-MB-231) using resazurin test, inhibitor, blocker, and anti-oxidant analysis, and siRNA interference. To avoid acyl migration in 2-AG, we replaced it with the analog 2-arachidonoyl-1,3-difluoropropanol (2-ADFP) newly synthesized by us. Using a molecular docking approach, we showed that at the CB2 receptor, 2-ADFP and 2-AG were very close to each other. However, 2-ADFP demonstrated a stronger affinity towards CB1 in the antagonist-bound conformation. 2-ADFP was anti-proliferative in all the cell lines tested. The toxicity of 2-ADFP was enhanced by LPI. 2-ADFP activity was reduced or prevented by the CB2 and vanilloid receptor 1 (TRPV1) blockers, inositol triphosphate receptor, CREB, and cyclooxygenase 2 inhibitor, and by anti-oxidant addition. Together with the literature data, these results indicate CB2- and TRPV1-dependent COX-2 induction with concomitant cell death induction by the oxidized molecule's metabolites.

Generalized, sublethal damage-based mathematical approach for improved modeling of clonogenic survival curve flattening upon hyperthermia, radiotherapy, and beyond

Objective. Mathematical modeling can offer valuable insights into the behavior of biological systems upon treatment. Different mathematical models (empirical, semi-empirical, and mechanistic) have been designed to predict the efficacy of either hyperthermia (HT), radiotherapy (RT), or their combination. However, mathematical approaches capable of modeling cell survival from shared general principles for both mono-treatments alone and their co-application are rare. Moreover, some cell cultures show dose-dependent saturation in response to HT or RT, manifesting in survival curve flattenings. An advanced survival model must, therefore, appropriately reflect such behavior.Approach. We propose a mathematical approach to model the effect of both treatments based on the general principle of sublethal damage (SLD) accumulation for the induction of cell death and irreversible proliferation arrest. Our approach extends Jung's model on heat-induced cellular inactivation by incorporating dose-dependent recovery rates that delineate changes in SLD restoration.Main results. The resulting unified model (Umodel) accurately describes HT and RT survival outcomes, applies to simultaneous thermoradiotherapy modeling, and is particularly suited to reproduce survival curve flattening phenomena. We demonstrate the Umodel's robust performance (R2 0.95) based on numerous clonogenic cell survival data sets from the literature and our experimental studies.Significance. The proposed Umodel allows using a single unified mathematical function based on generalized principles of accumulation of SLD with implemented radiosensitization, regardless of the type of energy deposited and the mechanism of action. It can reproduce various patterns of clonogenic survival curves, including any flattening, thus encompassing the variability of cell reactions to therapy, thereby potentially better reflecting overall tumor responses. Our approach opens a range of options for further model developments and strategic therapy outcome predictions of sequential treatments applied in different orders and varying recovery intervals between them.

Cobalt oxide nanoparticles induce cytotoxicity and excessive ROS mediated mitochondrial dysfunction and p53-independent apoptosis in melanoma cells

Nanotherapy has emerged as a promising strategy for the targeted and efficient treatment of melanoma, the most aggressive and lethal form of skin cancer, with minimized systemic toxicity. However, the therapeutic efficacy of cobalt oxide nanoparticles (Co3O4NPs) in melanoma treatment remains unexplored. This study aimed to assess the therapeutic potential of Co3O4NPs in melanoma treatment by evaluating their impact on cell viability, genomic DNA and mitochondrial integrity, reactive oxygen species (ROS) generation and apoptosis induction in melanoma A-375 cells. Our findings demonstrated a concentration-dependent reduction in cell viability upon treatment with five Co3O4NP concentrations (0.2, 2, 20, 200, and 2000 µg/ml), with an IC50 value of 303.80 µg/ml. Treatment with this IC50 concentration significantly increased ROS generation, induced dramatic DNA damage, and disrupted mitochondrial membrane potential integrity. Flow cytometric analysis revealed apoptosis and necrosis induction following Co3O4NP exposure at the IC50 concentration value. Results of qRT-PCR analysis demonstrated remarkable dysregulation of apoptotic and mitochondrial genes, including a significant downregulation of apoptotic p53 and mitochondrial ND3 genes and marked upregulation of the anti-apoptotic gene Bcl2. These findings highlight the novel potential of Co3O4NPs as potent inducers of melanoma A-375 cell death in a concentration-dependent manner through excessive ROS production, genomic instability, mitochondrial dysfunction and dysregulation of apoptotic and mitochondrial gene expression, ultimately promoting apoptosis in A-375 cells. This study thus underscores the potential of Co3O4NPs as a promising nanotherapeutic candidate for melanoma treatment, warranting further exploration to elucidate their full biological and clinical applicability.

In Vitro Evaluation of the Safety and Efficacy of Cibisatamab Using Adult Stem Cell-Derived Organoids and Colorectal Cancer Spheroids.

Objectives: Developing ex vivo models that replicate immune-tumor interactions with high fidelity is essential for advancing immunotherapy research, as traditional two-dimensional in vitro systems often lack the complexity required to fully represent these interactions. Methods: In this study, we establish a comprehensive 3D redirect lysis (3D-RDL) assay using colorectal cancer spheroids and adult stem cell-derived, healthy human organoids to evaluate the efficacy and safety profile of Cibisatamab, a bispecific antibody targeting carcinoembryonic antigens (CEAs) on cancer cells and CD3 on T cells. This model allows us to assess cytotoxic activity and immune responses, capturing variations in therapeutic response not observable in simpler systems. Our model integrates live imaging and cytotoxicity analyses to enable precise, real-time tracking of antibody effects on CEA-expressing tumor cells compared to healthy cells. Additionally, by standardizing effector-to-target cell ratios in each co-culture, we establish a reproducible workflow that enhances data accuracy and comparability across assays. Flow cytometry and Granzyme B release profiling further allow us to characterize immune cell activation, revealing distinct T cell activation markers and Granzyme B release patterns tied to Cibisatamab treatment. Results: Our results show that Cibisatamab effectively induces cell death in cancer spheroids with high CEA expression while being dose-dependent on target, off-tumor binding and killing on non-cancerous cells of healthy organoids with intermediate CEA levels. This highlights our model's potential to predict clinical immunotherapy outcomes, capturing complex responses like immune activation, therapeutic selectivity, and potential resistance mechanisms. Conclusions: These findings underscore the utility of our model as a reliable, physiologically relevant tool for screening new immunotherapies and advancing our understanding of tumor-immune dynamics.

Relationship Between the Salivary Microbiome and Oral Malodor Metabolites in Older Thai Individuals with Periodontitis and the Cytotoxic Effects of Malodor Compounds on Human Oral Squamous Carcinoma (HSC-4) Cells.

Background/Objectives: Halitosis is primarily caused by the activity of oral microorganisms. In this study, we employed metagenomic sequencing and metabolomic approaches to investigate the differences in salivary microbiota and metabolite profiles between individuals with halitosis and periodontitis and healthy controls. Additionally, we expanded the study to examine how oral malodorous compounds interact with human oral squamous carcinoma (HSC-4) cells. Methods: Saliva samples were collected and analyzed using Ultra-High Performance Liquid Chromatography-Mass Spectrometry (UHPLC-MS) to identify metabolites. We then assessed the correlations between the microbiota and metabolites. Furthermore, the impact of oral malodorous substances on HSC-4 cells was investigated by evaluating apoptosis, antioxidant activity, and inflammatory properties. Results: The microbiota and metabolite profiles showed significant differences between the halitosis with periodontitis group and the periodontally healthy group. The halitosis with periodontitis group exhibited significantly higher relative abundances of eight genera: Tannerella, Selenomonas, Bacteroides, Filifactor, Phocaeicola, Fretibacterium, Eubacterium saphenum, and Desulfobulbus. In contrast, the periodontally healthy group showed significantly higher relative abundances of Family XIII UCG-001, Haemophilus, and Streptobacillus. Two metabolites, 2,3-dihydro-1H-indole and 10,11-dihydro-12R-hydroxy-leukotriene E4, were significantly higher in individuals with halitosis and periodontitis. In the treatment of HSC-4 cells with metabolites, dimethyl sulfide (DMS) did not show significant effects while indole appeared to induce cell death in HSC-4 cells by triggering apoptotic pathways. Additionally, both indole and DMS affected the inflammatory and antioxidant properties of HSC-4 cells. Conclusions: This study provides insights into the mechanisms of halitosis by exploring the correlations between microbiota and metabolite profiles. Furthermore, oral metabolites were shown to impact the cellular response of HSC-4 cells.

Mechanisms of Copper-Induced Autophagy and Links with Human Diseases.

As a structural and catalytic cofactor, copper is involved in many biological pathways and is required for the biochemistry of all living organisms. However, excess intracellular copper can induce cell death due to its potential to catalyze the generation of reactive oxygen species, thus copper homeostasis is strictly regulated. And the deficiency or accumulation of intracellular copper is connected with various pathological conditions. Since the success of platinum-based compounds in the clinical treatment of various types of neoplasias, metal-based drugs have shown encouraging perspectives for drug development. Compared to platinum, copper is an essential intracellular trace element that may have better prospects for drug development than platinum. Recently, the potential therapeutic role of copper-induced autophagy in chronic diseases such as Parkinson's, Wilson's, and cardiovascular disease has already been demonstrated. In brief, copper ions, numerous copper complexes, and copper-based nano-preparations could induce autophagy, a lysosome-dependent process that plays an important role in various human diseases. In this review, we not only focus on the current advances in elucidating the mechanisms of copper or copper-based compounds/preparations on the regulation of autophagy but also outline the association between copper-induced autophagy and human diseases.

Energy Metabolism and Stemness and the Role of Lauric Acid in Reversing 5-Fluorouracil Resistance in Colorectal Cancer Cells.

While 5-fluorouracil (5FU) plays a central role in chemotherapy for colorectal cancer (CRC), resistance to 5FU remains a major challenge in CRC treatment, and its underlying mechanisms remain unclear. In this study, we investigated the relationship between 5FU resistance acquisition, stemness, and energy metabolism. Among the two CRC cell lines, HT29 cells exhibited glycolytic and quiescent properties, while CT26 cells relied on oxidative phosphorylation (OXPHOS) for energy. In contrast, the 5FU-resistant sublines (HT29R and CT26R), developed through continuous exposure to low concentrations of 5FU, demonstrated enhanced stemness. This was associated with glycolytic dominance, low proliferation, and reduced reactive oxygen species (ROS) production. However, treatment with the medium-chain fatty acid lauric acid shifted the cells to OXPHOS, reducing stemness, increasing ROS levels, and inducing cell death, therefore reversing 5FU resistance. These findings suggest that an enhancement in stemness and the reprogramming of energy metabolism play key roles in acquiring 5FU resistance in CRC. While lauric acid reversed 5FU resistance, further clinical studies are required.

Synthesis and Evaluation of Cytotoxic Activity of RuCp(II) Complexes Bearing (Iso)nicotinic Acid Based Ligands.

Cancer remains one of the major challenges of our century. Organometallic ruthenium complexes are gaining recognition as a highly promising group of compounds in the development of cancer treatments. Building on the auspicious results obtained for [Ru(η5-C5H5)(PPh3)(bipy)][CF3SO3] (TM34), our focus has shifted to examining the effects of incorporating bioactive ligands into the TM34 framework, particularly within the cyclopentadienyl ring. In this study, we report the synthesis and characterization of two new ruthenium(II) complexes with the general formula [Ru(η5-C5H4CCH3=R)(PPh3)(bipy)][CF3SO3], where R represents a nicotinic acid derivative (NNHCO(py-3-yl)) (1) or an isoniazid derivative (NNHCO(py-4-yl)) (2). The complexes were fully characterized using a combination of spectroscopic techniques and computational analysis, revealing the presence of E/Z-hydrazone isomerism. Stability studies confirmed the robustness of both complexes in biological media, with compound 1 maintaining good stability in buffer solutions mimicking physiological (pH 7.4) and tumor-like (pH 6.8) environments. The cytotoxicity of the complexes was evaluated in vitro in several human cancer cell lines, namely melanoma (A375), alveolar adenocarcinoma (A549), epidermoid carcinoma (A431), and breast cancer (MDA-MB 231). Both compounds exhibited moderate to high cytotoxic activity, with complex 1 showing a greater propensity to induce cell death, particularly in the A431 and MDA-MB 231 cell lines.

Importance of OsRac1 in Signalling of Pigm-1 Mediated Resistance to Rice Blast Disease.

In rice, leucine-rich repeat nucleotide-binding site (NLR) proteins are pivotal immune receptors in combating Magnaporthe oryzae-triggered rice blast. However, the precise molecular mechanism underlying how NLR proteins regulate downstream signalling remains elusive due to the lack of knowledge regarding their direct downstream targets. The NLR protein Pigm-1 was cloned from Shuangkang 77009 in our laboratory. This study shows that the nucleotide-binding site (NBS) domain of Pigm-1 facilitates its binding to and activation of OsRac1 while the coiled-coil (CC) domain enables its binding to and activation of RAI1, ultimately inducing cell death. At the same time, after knocking out OsRac1 in the background of Shuangkang 77009 containing Pigm-1, two knockout lines showed susceptibility to rice blast. This study reveals OsRac1, a GTPase, as a signalling molecule involved in Pigm-1-mediated blast resistance, suggesting its potential as a common downstream effector of rice NLR proteins. Additionally, a transcriptional activator, RAI1, acts as an essential Pigm-1 interactor for blast resistance. Furthermore, a novel material 9311(Pigm-1) was prepared by using two-line restorer line 9311 as receptor and Shuangkang 77009 as donor with molecular marker-assisted technology, which improved blast resistance and yield. This research demonstrates that molecular marker-assisted selection technology enhances both resistance and yield in the crucial two-line restorer 9311(Pigm-1). This study offers crucial insights into how Pigm-1 protein activates downstream molecules and serves as a valuable reference for the molecular breeding of rice blast resistance genes, particularly Pigm-1.

Mitochondrial dysfunction is a major cause of thromboinflammation and inflammatory cell death in critical illnesses.

Mitochondria generate the adenosine triphosphate (ATP) necessary for eukaryotic cells, serving as their primary energy suppliers, and contribute to host defense by producing reactive oxygen species. In many critical illnesses, including sepsis, major trauma, and heatstroke, the vicious cycle between activated coagulation and inflammation results in tissue hypoxia-induced mitochondrial dysfunction, and impaired mitochondrial function contributes to thromboinflammation and cell death. A computer-based online search was performed using the PubMed and Web of Science databases for published articles concerning sepsis, trauma, critical illnesses, cell death, mitochondria, inflammation, coagulopathy, and organ dysfunction. Mitochondrial outer membrane permeabilization triggers apoptosis by releasing cytochrome c and activating caspases. Apoptosis is a non-inflammatory programmed cell death but requires sufficient ATP supply. Therefore, conversion to inflammatory necrosis may occur due to a lack of ATP in critical illness. Severely damaged mitochondria release excess reactive oxygen species and injurious mitochondrial DNA, inducing cell death. Besides non-programmed necrosis, mitochondrial damage can trigger programmed inflammatory cell death, including necroptosis, pyroptosis, and ferroptosis. Additionally, a unique form of DNA-ejecting cell death, known as etosis, occurs in monocytes and granulocytes following external stimuli and mitochondrial damage. The type of cell death chosen remains uncertain but is known to depend on the cell type, the nature of the injury, and the degree of damage. Mitochondria damage is the major contributor to the cell death mechanism that leads to organ damage in critical illnesses. Regulating and restoring mitochondrial function holds promise for developing new therapeutic approaches for mitigating critical diseases.