Regulation of Cell Death by Mitochondrial Transport Systems of Calcium and Bcl-2 Proteins

MCU inhibition protects against intestinal ischemia‒reperfusion by inhibiting Drp1-dependent mitochondrial fission

Intestinal ischemia‒reperfusion (IIR) injury is a common complication of surgery, but clear molecular insights and valuable therapeutic targets are lacking. Mitochondrial calcium overload is an early sign of various diseases and is considered a vital factor in ischemia‒reperfusion injury. The mitochondrial calcium uniporter (MCU), which is located on the inner mitochondrial membrane, is the primary mediator of calcium ion entry into the mitochondria. However, the specific mechanism of MCU in IIR injury remains to be clarified. In this study, we generated an IIR model using C57BL/6 mice and Caco-2 cells and found increases in the calcium levels and MCU expression following IIR injury. The specific inhibition of MCU markedly attenuated IIR injury. Moreover, MCU knockdown alleviates mitochondrial dysfunction by reducing oxidative stress and apoptosis. Mechanistically, MCU knockdown substantially reduced the translocation of Drp1 and thus its binding to Fis1 receptors, resulting in decreased mitochondrial fission. Taken together, our findings demonstrated that MCU is a novel upstream regulator of Drp1 in ischemia‒reperfusion and represents a predictive and therapeutic target for IIR.

Extracellular vesicles: opening up a new perspective for the diagnosis and treatment of mitochondrial dysfunction

Mitochondria are crucial organelles responsible for energy generation in eukaryotic cells. Oxidative stress, calcium disorders, and mitochondrial DNA abnormalities can all cause mitochondrial dysfunction. It is now well documented that mitochondrial dysfunction significantly contributes to the pathogenesis of numerous illnesses. Hence, it is vital to investigate innovative treatment methods targeting mitochondrial dysfunction. Extracellular vesicles (EVs) are cell-derived nanovesicles that serve as intercellular messengers and are classified into small EVs (sEVs, < 200 nm) and large EVs (lEVs, > 200 nm) based on their sizes. It is worth noting that certain subtypes of EVs are rich in mitochondrial components (even structurally intact mitochondria) and possess the ability to transfer them or other contents including proteins and nucleic acids to recipient cells to modulate their mitochondrial function. Specifically, EVs can modulate target cell mitochondrial homeostasis as well as mitochondria-controlled apoptosis and ROS generation by delivering relevant substances. In addition, the artificial modification of EVs as delivery carriers for therapeutic goods targeting mitochondria is also a current research hotspot. In this article, we will focus on the ability of EVs to modulate the mitochondrial function of target cells, aiming to offer novel perspectives on therapeutic approaches for diverse conditions linked to mitochondrial dysfunction.

Apoptosis and eryptosis: similarities and differences

Eryptosis is a regulated cell death (RCD) of mature erythrocytes initially described as a counterpart of apoptosis for enucleated cells. However, over the recent years, a growing number of studies have emphasized certain differences between both cell death modalities. In this review paper, we underline the hallmarks of eryptosis and apoptosis and highlight resemblances and dissimilarities between both RCDs. We summarize and critically discuss differences in the impact of caspase-3, Ca2+ signaling, ROS signaling pathways, opposing roles of casein kinase 1α, protein kinase C, Janus kinase 3, cyclin-dependent kinase 4, and AMP-activated protein kinase to highlight a certain degree of divergence between apoptosis and eryptosis. This review emphasizes the crucial importance of further studies that focus on deepening our knowledge of cell death machinery and identifying novel differences between cell death of nucleated and enucleated cells. This might provide evidence that erythrocytes can be defined as viable entities capable of programmed cell destruction. Additionally, the revealed cell type-specific patterns in cell death can facilitate the development of cell death-modulating therapeutic agents.

Mn-Anti-CTLA4-CREKA-Sericin Nanotheragnostics for Enhanced Magnetic Resonance Imaging and Tumor Immunotherapy

The integration of magnetic resonance imaging (MRI), cGAS-STING, and anti-CTLA-4 (aCTLA-4) based immunotherapy offers new opportunities for tumor precision therapy. However, the precise delivery of aCTLA-4 and manganese (Mn), an activator of cGAS, to tumors remains a major challenge for enhanced MRI and active immunotherapy. Herein, a theragnostic nanosphere Mn-CREKA-aCTLA-4-SS (MCCS) is prepared by covalently assembling Mn2+, silk sericin (SS), pentapeptide CREKA, and aCTLA-4. MCCS are stable with an average size of 160 nm and is almost negatively charged or neutral at pH 5.5/7.4. T1-weighted images showed MCCS actively targeted tumors to improve the relaxation rate r1 and contrast time of MRI. This studies demonstrated MCCS raises reactive oxygen species levels, activates the cGAS-STING pathway, stimulates effectors CD8+ and CD80+ T cells, reduces regulatory T cell numbers, and increases IFN-γ and granzyme secretion, thereby inducing tumor cells autophagy and apoptosis in vitro and in vivo. Also, MCCS are biocompatible and biosafe. These studies show the great potential of Mn-/SS-based integrative material MCCS for precision and personalized tumor nanotheragnostics.

O-GlcNAcylation: a pro-survival response to acute stress in the cardiovascular and central nervous systems

O-GlcNAcylation is a unique monosaccharide modification that is ubiquitously present in numerous nucleoplasmic and mitochondrial proteins. The hexosamine biosynthesis pathway (HBP), which is a key branch of glycolysis, provides the unique sugar donor UDP-GlcNAc for the O-GlcNAc modification. Thus, HBP/O-GlcNAcylation can act as a nutrient sensor to perceive changes in nutrient levels and trigger O-GlcNAc modifications of functional proteins in cellular (patho-)physiology, thereby regulating diverse metabolic processes. An imbalance in O-GlcNAcylation has been shown to be a pathogenic contributor to dysfunction in metabolic diseases, including type 2 diabetes, cancer, and neurodegeneration. However, under acute stress conditions, protein O-GlcNAc modification exhibits rapid and transient upregulation, which is strongly correlated with stress tolerance and cell survival. In this context, we discuss the metabolic, pharmacological and genetic modulation of HBP/O-GlcNAc modification in the biological system, the beneficial role of O-GlcNAcylation in regulating stress tolerance for cardioprotection, and neuroprotection, which is a novel and rapidly growing field. Current evidence suggests that transient activation of the O-GlcNAc modification represents a potent pro-survival signalling pathway and may provide a promising strategy for stress-related disorder therapy.

Sesquiterpene lactones as emerging biomolecules to cease cancer by targeting apoptosis

Apoptosis is a programmed cell death comprising two signaling cascades including the intrinsic and extrinsic pathways. This process has been shown to be involved in the therapy response of different cancer types, making it an effective target for treating cancer. Cancer has been considered a challenging issue in global health. Cancer cells possess six biological characteristics during their developmental process known as cancer hallmarks. Hallmarks of cancer include continuous growth signals, unlimited proliferation, resistance to proliferation inhibitors, apoptosis escaping, active angiogenesis, and metastasis. Sesquiterpene lactones are one of the large and diverse groups of planet-derived phytochemicals that can be used as sources for a variety of drugs. Some sesquiterpene lactones possess many biological activities such as anti-inflammatory, anti-viral, anti-microbial, anti-malarial, anticancer, anti-diabetic, and analgesic. This review article briefly overviews the intrinsic and extrinsic pathways of apoptosis and the interactions between the modulators of both pathways. Also, the present review summarizes the potential effects of sesquiterpene lactones on different modulators of the intrinsic and extrinsic pathways of apoptosis in a variety of cancer cell lines and animal models. The main purpose of the present review is to give a clear picture of the current knowledge about the pro-apoptotic effects of sesquiterpene lactones on various cancers to provide future direction in cancer therapeutics.

Carboxylated Pocoa polysaccharides inhibited oxidative damage and inflammation of HK-2 cells induced by calcium oxalate nanoparticles

The inhibitory effects of Chinese medicine Pocoa (PCPs) with different carboxyl group (-COOH) contents on oxidative damage and inflammatory response of renal epithelial cells and the influence of -COOH content in polysaccharides were investigated. HK-2 cell damage model was established by nanocalcium oxalate crystals (nanoCOM), and then PCPs with -COOH contents of 2.56% (PCP0), 7.48% (PCP1), 12.07% (PCP2), and 17.18% (PCP3) were used to protect the cells. PCPs could inhibit the damage of nanoCOM to HK-2 cells, increase cell viability, restore cytoskeleton and morphology, and improve lysosomal integrity. PCPs can reduce the oxidative stress response of nanoCOM to cells, inhibit the opening of mPTP and cell necrotic apoptosis, reduce the level of Ca2+ ions in cells, the production of ATP and MDA, and increase SOD expression. PCPs can also reduce the cellular inflammatory response caused by oxidative damage, and reduce the expression of nitric oxide (NO), inflammatory factors TNF-α, IL-6, IL-1β and MCP-1, as well as the content of inflammasome NLRP3. After protection, PCPs can inhibit the endocytosis of nanoCOM crystals by cells. With the increase in -COOH content in PCPs, its ability to inhibit nanoCOM cell damage, reduce oxidative stress, reduce inflammatory response, and inhibit crystal endocytosis increases, that is, PCP3 with the highest -COOH content, shows the best biological activity. Inhibiting cell damage and inflammation and reducing a large amount of endocytosis of crystals by cells are beneficial to inhibit the formation of kidney stones.

Elucidating the Influence of MPT-driven necrosis-linked LncRNAs on immunotherapy outcomes, sensitivity to chemotherapy, and mechanisms of cell death in clear cell renal carcinoma

Background

Clear cell renal carcinoma (ccRCC) stands as the prevailing subtype among kidney cancers, making it one of the most prevalent malignancies characterized by significant mortality rates. Notably,mitochondrial permeability transition drives necrosis (MPT-Driven Necrosis) emerges as a form of cell death triggered by alterations in the intracellular microenvironment. MPT-Driven Necrosis, recognized as a distinctive type of programmed cell death. Despite the association of MPT-Driven Necrosis programmed-cell-death-related lncRNAs (MPTDNLs) with ccRCC, their precise functions within the tumor microenvironment and prognostic implications remain poorly understood. Therefore, this study aimed to develop a novel prognostic model that enhances prognostic predictions for ccRCC.

Methods

Employing both univariate Cox proportional hazards and Lasso regression methodologies, this investigation distinguished genes with differential expression that are intimately linked to prognosis.Furthermore, a comprehensive prognostic risk assessment model was established using multiple Cox proportional hazards regression. Additionally, a thorough evaluation was conducted to explore the associations between the characteristics of MPTDNLs and clinicopathological features, tumor microenvironment, and chemotherapy sensitivity, thereby providing insights into their interconnectedness.The model constructed based on the signatures of MPTDNLs was verified to exhibit excellent prediction performance by Cell Culture and Transient Transfection, Transwell and other experiments.

Results

By analyzing relevant studies, we identified risk scores derived from MPTDNLs as an independent prognostic determinant for ccRCC, and subsequently we developed a Nomogram prediction model that combines clinical features and associated risk assessment. Finally, the application of experimental techniques such as qRT-PCR helped to compare the expression of MPTDNLs in healthy tissues and tumor samples, as well as their role in the proliferation and migration of renal clear cell carcinoma cells. It was found that there was a significant correlation between CDK6-AS1 and ccRCC results, and CDK6-AS1 plays a key role in the proliferation and migration of ccRCC cells. Impressive predictive results were generated using marker constructs based on these MPTDNLs.

Conclusions

In this research, we formulated a new prognostic framework for ccRCC, integrating mitochondrial permeability transition-induced necrosis. This model holds significant potential for enhancing prognostic predictions in ccRCC patients and establishing a foundation for optimizing therapeutic strategies.

Antiproliferative and Cytotoxic Properties of Propynoyl Betulin Derivatives against Human Ovarian Cancer Cells: In Vitro Studies

Due to the incidence of ovarian cancer (OC) and the limitations of available therapeutic strategies, it is necessary to search for novel therapeutic solutions. The aim of this study was to evaluate the cytotoxic effect of betulin 1 and its propynoyl derivatives 2-6 against ovarian cancer cells (SK-OV-3, OVCAR-3) and normal myofibroblasts (18Co). Paclitaxel was used as the reference compound. The propynoyl derivatives 2-6 exhibited stronger antiproliferative and cytotoxic activities compared to betulin 1. In both ovarian cancer cell lines, the most potent compound was 28-propynoylbetulin 2. In the case of compound 2, the calculated IC50 values were 0.2 µM for the SK-OV-3 cells and 0.19 µM for the OVCAR-3 cells. Under the same culture conditions, the calculated IC50 values for compound 6 were 0.26 µM and 0.59 µM, respectively. It was observed that cells treated with compounds 2 and 6 caused a decrease in the potential of the mitochondrial membrane and a significant change in cell morphology. Betulin 1, a diol from the group of pentacyclic triterpenes, has a confirmed wide spectrum of biological effects, including a significant anticancer effect. It is characterized by low bioavailability, which can be improved by introducing changes to its structure. The results showed that chemical modifications of betulin 1 only at position C-28 with the propynoyl group (compound 2) and additionally at position C-3 with the phosphate group (compound 3) or at C-29 with the phosphonate group (compound 6) allowed us to obtain compounds with greater cytotoxic activity than their parent compounds, which could be used to develop novel therapeutic systems effective in the treatment of ovarian cancer.

New Combretastatin Analogs as Anticancer Agents: Design, Synthesis, Microtubules Polymerization Inhibition, and Molecular Docking Studies

A new series of 4-(4-methoxyphenyl)-5-(3,4,5-trimethoxyphenyl)-4H-1,2,4-triazole-3-thiol derivatives were synthesized as analogs for the anticancer drug combretastatin A-4 (CA-4) and characterized using FT-IR, 1 H-NMR, 13 CNMR, and HR-MS techniques. The new CA-4 analogs were designed to meet the structural requirements of the highest expected anticancer activity of CA-4 analogs by maintaining ring A 3,4,5-trimethoxyphenyl moiety, and at the same time varying the substituents effect of the triazole moiety (ring B). In silico analysis indicated that compound 3 has higher total energy and dipole moment than colchicine and the other analogs, and it has excellent distribution of electron density and is more stable, resulting in an increased binding affinity during tubulin inhibition. Additionally, compound 3 was found to interact with three apoptotic markers, namely p53, Bcl-2, and caspase 3. Compound 3 showed strong similarity to colchicine, and it has excellent pharmacokinetics properties and a good dynamic profile. The in vitro anti-proliferation studies showed that compound 3 is the most cytotoxic CA-4 analog against cancer cells (IC50 of 6.35 μM against Hep G2 hepatocarcinoma cells), and based on its selectivity index (4.7), compound 3 is a cancer cytotoxic-selective agent. As expected and similar to colchicine, compound 3-treated Hep G2 hepatocarcinoma cells were arrested at the G2/M phase resulting in induction of apoptosis. Compound 3 tubulin polymerization IC50 (9.50 μM) and effect on Vmax of tubulin polymerization was comparable to that of colchicine (5.49 μM). Taken together, the findings of the current study suggest that compound 3, through its binding to the colchicine-binding site at β-tubulin, is a promising microtubule-disrupting agent with excellent potential to be used as cancer therapeutic agent.

Chemical Compositions and Experimental and Computational Modeling of the Anticancer Effects of Cnidocyte Venoms of Jellyfish Cassiopea andromeda and Catostylus mosaicus on Human Adenocarcinoma A549 Cells

Nowadays, major attention is being paid to curing different types of cancers and is focused on natural resources, including oceans and marine environments. Jellyfish are marine animals with the ability to utilize their venom in order to both feed and defend. Prior studies have displayed the anticancer capabilities of various jellyfish. Hence, we examined the anticancer features of the venom of Cassiopea andromeda and Catostylus mosaicus in an in vitro situation against the human pulmonary adenocarcinoma (A549) cancer cell line. The MTT assay demonstrated that both mentioned venoms have anti-tumoral ability in a dose-dependent manner. Western blot analysis proved that both venoms can increase some pro-apoptotic factors and reduce some anti-apoptotic molecules that lead to the inducing of apoptosis in A549 cells. GC/MS analysis demonstrated some compounds with biological effects, including anti-inflammatory, antioxidant and anti-cancer activities. Molecular docking and molecular dynamic showed the best position of each biologically active component on the different death receptors, which are involved in the process of apoptosis in A549 cells. Ultimately, this study has proven that both venoms of C. andromeda and C. mosaicus have the capability to suppress A549 cells in an in vitro condition and they might be utilized in order to design and develop brand new anticancer agents in the near future.

NEPHROPROTECTIVE EFFECT OF OLMESARTAN ON RENAL ISCHEMIA REPERFUSION INJURY IN MALE RATS: THE ROLE OF NRF2/HO-1 SIGNALING PATHWAY

OBJECTIVE

The aim: To investigate the Nephroprotective potential of Olmesartan in RIRI via modulation of the Nrf2/OH-1 signaling pathway.

PATIENTS AND METHODS

Materials and methods: Thirty male rats were equally divided into four groups. The sham group was exposed to surgical conditions without induction of RIRI. The control group was exposed to ischemia by clamping the renal pedicles for 30 min, followed by 2h of blood restoration. The vehicle-treated group was received dimethyl sulfoxide (DMSO) by intraperitoneal injection (IP) 30 min before clamping.

RESULTS

Results: Olmesartan-treated group was pretreated with Olmesartan a dose of 10 mg/kg IP; 30 min prior to induction of ischemia. Following 30 min of ischemia, the clamps were released and allowed to the reperfusion for 2 h. Blood samples were collected to examine the levels of serum urea and creatinine. Kidney tissue was used to measure the levels of cytokines (TNFα, IL6, MCP, BAX, BCL2 and isoprostane F2. Immunohistochemistry was used to assess the levels of Nrf2 and HO-1. Histological analyses were used to detect the tubular damage in the kidney.

CONCLUSION

Conclusions: The results showed that Olmesartan alleviates renal tissue damage through activating the antioxidant effect mediated by Nrf2 signaling.

Novel therapeutic strategies targeting mitochondria as a gateway in neurodegeneration

In recent years, multiple disciplines have focused on mitochondrial biology and contributed to understanding its relevance towards adult-onset neurodegenerative disorders. These are complex dynamic organelles that have a variety of functions in ensuring cellular health and homeostasis. The plethora of mitochondrial functionalities confers them an intrinsic susceptibility to internal and external stressors (such as mutation accumulation or environmental toxins), particularly so in long-lived postmitotic cells such as neurons. Thus, it is reasonable to postulate an involvement of mitochondria in aging-associated neurological disorders, notably neurodegenerative pathologies including Alzheimer's disease and Parkinson's disease. On the other hand, biological effects resulting from neurodegeneration can in turn affect mitochondrial health and function, promoting a feedback loop further contributing to the progression of neuronal dysfunction and cellular death. This review examines state-of-the-art knowledge, focus on current research exploring mitochondrial health as a contributing factor to neuroregeneration, and the development of therapeutic approaches aimed at restoring mitochondrial homeostasis in a pathological setting.

Dichloroacetate as a metabolic modulator of heart mitochondrial proteome under conditions of reduced oxygen utilization

Myocardial compensatory mechanisms stimulated by reduced oxygen utilization caused by streptozotocin-induced diabetes mellitus (DM) and treated with dichloroacetate (DCA) are presumably associated with the regulation of mitochondria. We aimed to promote the understanding of key signaling pathways and identify effectors involved in signal transduction. Proteomic analysis and fluorescence spectroscopy measurements revealed significantly decreased membrane potential and upregulated protein amine oxidase [flavin-containing] A (AOFA) in DM mitochondria, indicative of oxidative damage. DCA in diabetic animals (DM + DCA) downregulated AOFA, increased membrane potential, and stimulated thioredoxin-dependent peroxide reductase, a protein with antioxidant function. Furthermore, the DM condition was associated with mitochondrial resistance to calcium overload through mitochondrial permeability transition pores (mPTPs) regulation, despite an increased protein level of voltage-dependent anion-selective protein (VDAC1). In contrast, DM + DCA influenced ROS levels and downregulated VDAC1 and VDAC3 when compared to DM alone. The diabetic myocardium showed an identical pattern of mPTP protein interactions as in the control group, but the interactions were attenuated. Characterization of the combined effect of DM + DCA is a novel finding showing that DCA acted as an effector of VDAC protein interactions, calcium uptake regulation, and ROS production. Overall, DM and DCA did not exhibit an additive effect, but an individual cardioprotective pathway.

Preventing Axonal Sodium Overload or Mitochondrial Calcium Uptake Protects Axonal Mitochondria from Oxidative Stress-Induced Alterations

In neuroinflammatory and neurodegenerative disorders such as multiple sclerosis, mitochondrial damage caused by oxidative stress is believed to contribute to neuroaxonal damage. Previously, we demonstrated that exposure to hydrogen peroxide (H₂O₂) alters mitochondrial morphology and motility in myelinated axons and that these changes initiate at the nodes of Ranvier, where numerous sodium channels are located. Therefore, we suggested that mitochondrial damage may lead to ATP deficit, thereby affecting the efficiency of the sodium-potassium ATPase and eventually leading to sodium overload in axons. The increased intra-axonal sodium may revert the axonal sodium-calcium exchangers and thus may lead to a pathological calcium overload in the axoplasm and mitochondria. Here, we used the explanted murine ventral spinal roots to investigate whether modulation of sodium or calcium influx may prevent mitochondrial alterations in myelinated axons during exogenous application of H₂O₂ inducing oxidative stress. For that, tetrodotoxin, an inhibitor of voltage-gated sodium ion channels, and ruthenium 360, an inhibitor of the mitochondrial calcium uniporter, were applied simultaneously with hydrogen peroxide to axons. Mitochondrial shape and motility were analyzed. We showed that inhibition of axonal sodium influx prevented oxidative stress-induced morphological changes (i.e., increase in circularity and area and decrease in length) and preserved mitochondrial membrane potential, which is crucial for ATP production. Blocking mitochondrial calcium uptake prevented decrease in mitochondrial motility and also preserved membrane potential. Our findings indicate that alterations of both mitochondrial morphology and motility in the contexts of oxidative stress can be counterbalanced by modulating intramitochondrial ion concentrations pharmacologically. Moreover, motile mitochondria show preserved membrane potentials, pointing to a close association between mitochondrial motility and functionality.

Interaction between nanometer calcium oxalate and renal epithelial cells repaired with carboxymethylated polysaccharides

OBJECTIVE

Injury of renal tubular epithelial cells (HK-2) is an important cause of kidney stone formation. In this article, the repairing effect of polysaccharide (PCP0) extracted from the traditional Chinese medicine Poria cocos and its carboxymethylated derivatives on damaged HK-2 cells was studied, and the differences in adhesion and endocytosis of the cells to nanometer calcium oxalate monohydrate (COM) before and after repair were explored.

METHODS

Sodium oxalate (2.8 mmol/L) was used to damage HK-2 cells to establish a damage model, and then Poria cocos polysaccharides (PCPs) with different carboxyl (COOH) contents were used to repair the damaged cells. The changes in the biochemical indicators of the cells before and after the repair and the changes in the ability to adhere to and internalize nano-COM were detected.

RESULTS

The natural PCPs (PCP0, COOH content = 2.56%) were carboxymethylated, and three carboxylated modified Poria cocos with 7.48% (PCP1), 12.07% (PCP2), and 17.18% (PCP3) COOH contents were obtained. PCPs could repair the damaged HK-2 cells, and the cell viability was enhanced after repair. The cell morphology was gradually repaired, the proliferation and healing rate were increased. The ROS production was reduced, and the polarity of the mitochondrial membrane potential was restored. The level of intracellular Ca²⁺ ions decreased, and the autophagy response was weakened.

CONCLUSION

The cells repaired by PCPs inhibited the adhesion to nano-COM and simultaneously promoted the endocytosis of nano-COM. The endocytic crystals mainly accumulated in the lysosome. Inhibiting adhesion and increasing endocytosis could reduce the nucleation, growth, and aggregation of cell surface crystals, thereby inhibiting the formation of kidney stones. With the increase of COOH content in PCPs, its ability to repair damaged cells, inhibit crystal adhesion, and promote crystal endocytosis all increased, that is, PCP3 with the highest COOH content showed the best ability to inhibit stone formation.

The effects of coal dust exposure on DNA damage and repair of human bronchial epithelial cells

To explore the effects of coal dust exposure on DNA damage and repair, human bronchial epithelial BEAS-2B cells were exposed to coal dust and the cellular response was investigated. It was found that γ-H2AX foci of DNA damage appeared, γ-H2AX protein level increased, and the rate of cell apoptosis was significantly elevated when BEAS-2B cells were exposed to coal dust for a short time. Phagocytized coal dust particles, swollen mitochondria, and reduced mitochondrial membrane potential were simultaneously identified. Moreover, Caspase-9, Caspase-3, and DFF45 proteins of the mitochondrial apoptotic pathway were activated. After the cells were exposed to coal dust chronically, phosphorylation levels of DNA repair kinases (ATM/ATR, DNA-PKcs) and downstream regulatory protein AKT were significantly upregulated. γ-H2AX foci and tail DNA of the cells following treatment with cisplatin were also reduced, and the colony formation rate was improved. It was concluded that coal dust could induce DNA damage, cause mitochondrial depolarization, and activate mitochondrial apoptosis pathways in BEAS-2B cells. Additionally, activated DNA repair kinases (ATM/ATR and DNA-PKcs) and their regulatory protein AKT increased DNA repair and proliferation of BEAS-2B cells chronically exposed to coal dust.

Biochemical properties of H+-Ca2+-exchanger in the myometrium mitochondria

Some biochemical properties of the H⁺-Ca²⁺-exchanger in uterine smooth muscle mitochondria have been described. The experiments were performed on a suspension of isolated mitochondria from the myometrium of rats. Methods of confocal microscopy, spectrofluorimetry and photon correlation spectroscopy were used. Fluo-4 probe was used to record changes in ionized Ca²⁺ in the matrix and cytosol; pH changes in the matrix were evaluated with BCECF. It was experimentally proved that in the myometrium instead of Na⁺-Ca²⁺-exchanger the H⁺-Ca²⁺-exchanger functions. It was activated at a physiological pH value, was carried out in stoichiometry 1: 1 and was electrogenic. The transport system was modulated by magnesium ions and the diuretic amiloride, but was not sensitive to changes in the concentration of extra-mitochondrial potassium ions. H⁺-Ca²⁺-exchanger was suppressed by antibodies against the LETM1 protein. Calmodulin may act as a regulator of H⁺-Ca²⁺-exchanger by inhibiting it.

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It has been shown the possibility of the existence of H⁺-Ca²⁺-exchanger in the mitochondria of the myometrium.

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Functioning of H⁺-Ca²⁺-exchanger does not depend on the gradient of sodium and potassium ions; is activated at physiological pH values; is carried out in stoichiometry 1:1 and is electrogenic; inhibited by antibodies against LETM1 protein; modulated by the magnesium ions and diuretic amiloride; calmodulin may act as a regulator of H⁺-Ca²⁺-exchanger.

Discovery of novel quinoline-based analogues of combretastatin A-4 as tubulin polymerisation inhibitors with apoptosis inducing activity and potent anticancer effect

A new series of quinoline derivatives of combretastatin A-4 have been designed, synthesised and demonstrated as tubulin polymerisation inhibitors. These novel compounds showed significant antiproliferative activities, among them, 12c exhibited the most potent inhibitory activity against different cancer cell lines (MCF-7, HL-60, HCT-116 and HeLa) with IC50 ranging from 0.010 to 0.042 µM, and with selectivity profile against MCF-10A non-cancer cells. Further mechanistic studies suggest that 12c can inhibit tubulin polymerisation and cell migration, leading to G2/M phase arrest. Besides, 12c induces apoptosis via a mitochondrial-dependant apoptosis pathway and caused reactive oxygen stress generation in MCF-7 cells. These results provide guidance for further rational development of potent tubulin polymerisation inhibitors for the treatment of cancer.HighlightsA novel series of quinoline derivatives of combretastatin A-4 have been designed and synthesised.Compound 12c showed significant antiproliferative activities against different cancer cell lines.Compound 12c effectively inhibited tubulin polymerisation and competed with [3H] colchicine in binding to tubulin.Compound 12c arrested the cell cycle at G2/M phase, effectively inducing apoptosis and inhibition of cell migration.

Coupling/Uncoupling Reversibility in Isolated Mitochondria from Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae uses fermentation as the preferred pathway to obtain ATP and requires the respiratory chain to re-oxidize the NADH needed for activity of Glyceraldehyde-3-phosphate. This process is favored by uncoupling of oxidative phosphorylation (OxPhos), which is at least partially controlled by the mitochondrial unspecific pore (_ScMUC). When mitochondrial ATP synthesis is needed as in the diauxic phase or during mating, a large rise in Ca²⁺ concentration ([Ca²⁺]) closes _ScMUC, coupling OxPhos. In addition, _ScMUC opening/closing is mediated by the ATP/ADP ratio, which indicates cellular energy needs. Here, opening and closing of _ScMUC was evaluated in isolated mitochondria from S. cerevisiae at different incubation times and in the presence of different ATP/ADP ratios or varying [Ca²⁺]. Measurements of the rate of O₂ consumption, mitochondrial swelling, transmembrane potential and ROS generation were conducted. It was observed that _ScMUC opening was reversible, a high ATP/ADP ratio promoted opening and [Ca²⁺] closed _ScMUC even after several minutes of incubation in the open state. In the absence of ATP synthesis, closure of _ScMUC resulted in an increase in ROS.

The multifaceted roles of mitochondria at the crossroads of cell life and death in cancer

Mitochondria are the cytoplasmic organelles mostly known as the "electric engine" of the cells; however, they also play pivotal roles in different biological processes, such as cell growth/apoptosis, Ca²⁺ and redox homeostasis, and cell stemness. In cancer cells, mitochondria undergo peculiar functional and structural dynamics involved in the survival/death fate of the cell. Cancer cells use glycolysis to support macromolecular biosynthesis and energy production ("Warburg effect"); however, mitochondrial OXPHOS has been shown to be still active during carcinogenesis and even exacerbated in drug-resistant and stem cancer cells. This metabolic rewiring is associated with mutations in genes encoding mitochondrial metabolic enzymes ("oncometabolites"), alterations of ROS production and redox biology, and a fine-tuned balance between anti-/proapoptotic proteins. In cancer cells, mitochondria also experience dynamic alterations from the structural point of view undergoing coordinated cycles of biogenesis, fusion/fission and mitophagy, and physically communicating with the endoplasmic reticulum (ER), through the Ca²⁺ flux, at the MAM (mitochondria-associated membranes) levels. This review addresses the peculiar mitochondrial metabolic and structural dynamics occurring in cancer cells and their role in coordinating the balance between cell survival and death. The role of mitochondrial dynamics as effective biomarkers of tumor progression and promising targets for anticancer strategies is also discussed.

Towards Understanding the Involvement of H+-ATPase in Programmed Cell Death of Psammosilene tunicoides after Oxalic Acid Application

Psammosilene tunicoides is a unique perennial medicinal plant species native to the Southwestern regions of China. Its wild population is rare and endangered due to over-excessive collection and extended growth (4–5 years). This research shows that H⁺-ATPase activity was a key factor for oxalate-inducing programmed cell death (PCD) of P. tunicoides suspension cells. Oxalic acid (OA) is an effective abiotic elicitor that enhances a plant cell’s resistance to environmental stress. However, the role of OA in this process remains to be mechanistically unveiled. The present study evaluated the role of OA-induced cell death using an inverted fluorescence microscope after staining with Evans blue, FDA, PI, and Rd123. OA-stimulated changes in K⁺ and Ca²⁺ trans-membrane flows using a patch-clamp method, together with OA modulation of H⁺-ATPase activity, were further examined. OA treatment increased cell death rate in a dosage-and duration-dependent manner. OA significantly decreased the mitochondria activity and damaged its electron transport chain. The OA treatment also decreased intracellular pH, while the FC increased the pH value. Simultaneously, NH₄Cl caused intracellular acidification. The OA treatment independently resulted in 90% and the FC led to 25% cell death rates. Consistently, the combined treatments caused a 31% cell death rate. Furthermore, treatment with EGTA caused a similar change in intracellular pH value to the La³⁺ and OA application. Combined results suggest that OA-caused cell death could be attributed to intracellular acidification and the involvement of OA in the influx of extracellular Ca²⁺, thereby leading to membrane depolarization. Here we explore the resistance mechanism of P. tunicoides cells against various stresses endowed by OA treatment.

Altered Expression of DAAM1 and PREP Induced by Cadmium Toxicity Is Counteracted by Melatonin in the Rat Testis

Cadmium (Cd) is one of the most toxic pollutants for health due to its accumulation in several tissues, including testis. This report confirms that Cd increased oxidative stress and apoptosis of germ and somatic cells and provoked testicular injury, as documented by biomolecular and histological alterations, i.e., CAT and SOD activity, the protein level of steroidogenic enzymes (StAR and 3β-HSD), and morphometric parameters. Additionally, it further documents the melatonin (MLT) coadministration produces affects in mitigating Cd-induced toxicity on adult rat testis, as demonstrated by the reduction of oxidative stress and apoptosis, with reversal of the observed histological changes; moreover, a role of MLT in partially restoring steroidogenic enzymes expression was evidenced. Importantly, the cytoarchitecture of testicular cells was perturbed by Cd exposure, as highlighted by impairment of the expression and localization of two cytoskeleton-associated proteins DAAM1 and PREP, which are involved in the germ cells' differentiation into spermatozoa, altering the normal spermatogenesis. Here, for the first time, we found that the co-treatment with MLT attenuated the Cd-induced toxicity on the testicular DAAM1 and PREP expression. The combined findings provide additional clues about a protective effect of MLT against Cd-induced testicular toxicity by acting on DAAM1 and PREP expression, encouraging further studies to prove its effectiveness in human health.

Mitochondrial Targeting Involving Cholesterol-Rich Lipid Rafts in the Mechanism of Action of the Antitumor Ether Lipid and Alkylphospholipid Analog Edelfosine

The ether lipid edelfosine induces apoptosis selectively in tumor cells and is the prototypic molecule of a family of synthetic antitumor compounds collectively known as alkylphospholipid analogs. Cumulative evidence shows that edelfosine interacts with cholesterol-rich lipid rafts, endoplasmic reticulum (ER) and mitochondria. Edelfosine induces apoptosis in a number of hematological cancer cells by recruiting death receptors and downstream apoptotic signaling into lipid rafts, whereas it promotes apoptosis in solid tumor cells through an ER stress response. Edelfosine-induced apoptosis, mediated by lipid rafts and/or ER, requires the involvement of a mitochondrial-dependent step to eventually elicit cell death, leading to the loss of mitochondrial membrane potential, cytochrome c release and the triggering of cell death. The overexpression of Bcl-2 or Bcl-xL blocks edelfosine-induced apoptosis. Edelfosine induces the redistribution of lipid rafts from the plasma membrane to the mitochondria. The pro-apoptotic action of edelfosine on cancer cells is associated with the recruitment of F1FO-ATP synthase into cholesterol-rich lipid rafts. Specific inhibition of the FO sector of the F1FO-ATP synthase, which contains the membrane-embedded c-subunit ring that constitutes the mitochondrial permeability transcription pore, hinders edelfosine-induced cell death. Taking together, the evidence shown here suggests that the ether lipid edelfosine could modulate cell death in cancer cells by direct interaction with mitochondria, and the reorganization of raft-located mitochondrial proteins that critically modulate cell death or survival. Here, we summarize and discuss the involvement of mitochondria in the antitumor action of the ether lipid edelfosine, pointing out the mitochondrial targeting of this drug as a major therapeutic approach, which can be extrapolated to other alkylphospholipid analogs. We also discuss the involvement of cholesterol transport and cholesterol-rich lipid rafts in the interactions between the organelles as well as in the role of mitochondria in the regulation of apoptosis in cancer cells and cancer therapy.

The Interplay between Dysregulated Ion Transport and Mitochondrial Architecture as a Dangerous Liaison in Cancer

Transport of ions and nutrients is a core mitochondrial function, without which there would be no mitochondrial metabolism and ATP production. Both ion homeostasis and mitochondrial phenotype undergo pervasive changes during cancer development, and both play key roles in driving the malignancy. However, the link between these events has been largely ignored. This review comprehensively summarizes and critically discusses the role of the reciprocal relationship between ion transport and mitochondria in crucial cellular functions, including metabolism, signaling, and cell fate decisions. We focus on Ca²⁺, H⁺, and K⁺, which play essential and highly interconnected roles in mitochondrial function and are profoundly dysregulated in cancer. We describe the transport and roles of these ions in normal mitochondria, summarize the changes occurring during cancer development, and discuss how they might impact tumorigenesis.

A Walk in the Memory, from the First Functional Approach up to Its Regulatory Role of Mitochondrial Bioenergetic Flow in Health and Disease: Focus on the Adenine Nucleotide Translocator

The mitochondrial adenine nucleotide translocator (ANT) plays the fundamental role of gatekeeper of cellular energy flow, carrying out the reversible exchange of ADP for ATP across the inner mitochondrial membrane. ADP enters the mitochondria where, through the oxidative phosphorylation process, it is the substrate of Fo-F1 ATP synthase, producing ATP that is dispatched from the mitochondrion to the cytoplasm of the host cell, where it can be used as energy currency for the metabolic needs of the cell that require energy. Long ago, we performed a method that allowed us to monitor the activity of ANT by continuously detecting the ATP gradually produced inside the mitochondria and exported in the extramitochondrial phase in exchange with externally added ADP, under conditions quite close to a physiological state, i.e., when oxidative phosphorylation takes place. More than 30 years after the development of the method, here we aim to put the spotlight on it and to emphasize its versatile applicability in the most varied pathophysiological conditions, reviewing all the studies, in which we were able to observe what really happened in the cell thanks to the use of the "ATP detecting system" allowing the functional activity of the ANT-mediated ADP/ATP exchange to be measured.

Effect and mechanisms of LINC00152 knockdown on chemotherapy resistance in mitomycin-resistant gastric cancer NCI-N87/MMC cells

BACKGROUND

Long intergenic noncoding RNA 152 (LINC00152) is highly expressed in gastric cancer tissues, and it can promote the proliferation, migration, and invasion of gastric cancer cells. However, the effects and mechanisms of LINC00152 on chemotherapy resistance in gastric cancer are not clear.

AIM

To explore the effects and related mechanisms of LINC00152 on chemotherapy resistance in human gastric cancer cell line NCI-N87.

METHODS

The expression of LINC00152 in human gastric cancer cell line NCI-N87 and mitomycin (MMC) resistant cell line NCI-N87/MMC was detected by real-time PCR. After the expression of LINC00152 in NCI-N87/MMC cells was knocked down by RNA interference method, the sensitivity of cells to MMC and cisplatin was measured by MTT assay, cell apoptosis was detected by flow cytometry, and the protein expression levels of Bcl-2, Bax, Caspase 3, and cleaved Caspase 3 were determined by Western Blot. Furthermore, the expression levels of MDR1/P-gp, Mgr1-Ag, and MRP were evaluated by real-time PCR and Western Blot.

RESULTS

The expression level of INC00152 in NCI-N87/MMC cells was significantly higher than that in maternal NCI-N87 cells. LINC00152 knockdown induced apoptosis and increased sensitivity to MMC and cisplatin in NCI-N87/MMC cells. LINC00152 knockdown inhibited the expression of Bcl-2 protein in NCI-N87/MMC cells, but promoted the expression of Bax protein and the activation of Caspase 3. Furthermore, LINC00152 knockdown down-regulated the mRNA and protein expression of MDR1, Mgr1-Ag, and MRP in NCI-N87/MMC cells.

CONCLUSION

Down-regulation of LINC00152 in NCI-N87/MMC cells can increase the sensitivity of cells to MMC and cisplatin, and the mechanisms may be related to the promotion of cell apoptosis by regulating apoptotic-related factors, and down-regulation of MDR1, Mgr1-Ag, and MRP.