Activation Of Cell Death Mechanisms Research Articles

Multi-Enzyme Activity of MIL-101 (Fe)-Derived Cascade Nano-Enzymes for Antitumor and Antimicrobial Therapy.

The clinical application of oncology therapy is hampered by high glutathione concentrations, hypoxia, and inefficient activation of cell death mechanisms in cancer cells. In this study, Fe and Mo bimetallic sulfide nanomaterial (FeS2@MoS2) based on metal-organic framework structure is rationally prepared with peroxidase (POD)-, catalase (CAT)-, superoxide dismutase (SOD)-like activities and glutathione depletion ability, which can confer versatility for treating tumors and mending wounds. In the lesion area, FeS2@MoS2 with SOD-like activity can facilitate the transformation of superoxide anions (O2 -) to hydrogen peroxide (H2O2), and then the resulting H2O2 serves as a substrate for the Fenton reaction with FMS to produce highly toxic hydroxyl radicals (∙OH). Simultaneously, FeS2@MoS2 has an ability to deplete glutathione (GSH) and catalyze the decomposition of nicotinamide adenine dinucleotide phosphate (NADPH) to curb the regeneration of GSH from the source. Thus it can realize effective tumor elimination through synergistic apoptosis-ferroptosis strategy. Based on the alteration of the H2O2 system, free radical production, glutathione depletion and the alleviation of hypoxia in the tumor microenvironment, FeS2@MoS2 NPS can not only significantly inhibit tumors in vivo and in vitro, but also inhibit multidrug-resistant bacteria and hasten wound healing. It may open the door to the development of cascade nanoplatforms for effective tumor treatment and overcoming wound infection.

Study on the activation of cell death mechanisms: in search of new therapeutic targets in glioblastoma multiforme

Malignant primary brain tumors remain among the most difficult cancers to treat, in particular, Glioblastoma Multiforme (GBM) is the deadliest brain tumor. The standard therapies currently used are not efficient enough in improving patients’ survival and quality of life. Cisplatin (CDDP), a platinum-based drug, has shown efficacy against different solid neoplasms, but it is also associated to different forms of off-target toxicity. To overcome the limitation in the use of CDDP in the treatment of GBM patients, fourth generation platinum compounds are been synthesized, one of them is the Pt(IV)Ac-POA, a prodrug with a medium-chain fatty acid as axial ligand, which acts as a histone 3 deacetylase inhibitor. Moreover, recently, the antioxidant effects of medicinal mushrooms have been shown to induce a lowering of the toxicity of chemotherapy drugs, inducing greater therapeutic efficiency, thus the combined therapy of chemotherapy and micotherapy could be helpful in the treatment of GBM reducing the adverse effects of the former thanks to phytotherapy’s antioxidant, anti-inflammatory, immunomodulatory and antitumoral activities. Here, through immunoblotting, ultrastructural and immunofluorescence analysis, we evaluated the contribution in the activation of different cell death pathway of Micotherapy U-Care, a medicinal blend supplement, used together with platinum-based compounds on human glioblastoma U251 cells.

Tumor immune microenvironment and apoptotic markers in breast cancer patients carrying <I>BRCA1</I> gene mutations

Background. It is suggested that defects in BRCA1 / 2 genes contribute to a high mutational load and high immunogenicity, which modulates immune microenvironment. At the same time, it was shown that BRCA1 / 2-associated breast cancer tumors do not belong to the category of immunoactive ones. These tumors have low expression of immune response genes and exhibit an immunosuppressive type of microenvironment. This indicates the need of antitumor immune response modulation and maintaining of the optimal balance of tumor CD4/CD8 T-lymphocytes ratio. In addition, there is evidence of the additional evaluation of TP53 mutation in these tumors and disruption of the cell death process, which can also be a factor of resistance to therapy, including PARP inhibitors, and serve as a therapeutic target.Materials and methods. The prospective study included 20 patients with BRCA1-associated breast cancer. BRCA1 / 2 mutations (BRCA1 185delAG, 4153delA, 5382insC, 3819delGTAAA, 3875delGTCT, 300T>G, 2080delA, BRCA2 6174delT) were detected in by real-time polymerase chain reaction. Immunohistochemical study was performed on paraffin embedded tissue blocks by an automated method on a ThermoScentific immunohistotainer using monoclonal antibodies. The expression of markers of tumor-infiltrating CD4+ and CD8+ T-lymphocytes, markers of macrophages (CD68, CD163), apoptosis (Bcl-2, p53), cell adhesion markers (E-cadherin, β-catenin) in breast cancer in carriers of BRCA1 mutations was assessed.Results. High CD4/CD8 ratio, which characterizes immunosuppressive microenvironment, occurred in 75 % of cases. BRCA1 5382insC mutation is associated with high level of CD4+ TILs (p˂0.05), G2 is associated with a low CD4/CD8 ratio (p = 0.039) and a high level of CD163 (p = 0.02, AUC = 0.739); T1 correlates with high levels of CD8+ TILs (p = 0.038) and high levels of CD163 (p = 0.033). High Ki-67 is associated with a lack of Bcl-2 expression (p = 0.04) and a low level of E-cadherin (p = 0.02). Negative expression of Bcl-2 occurred in 75 % of cases. High level of p53 expression has been described as the main type of expression in these tumors, suggesting a combination of TB53 and BRCA1 mutations and a violation of cell death mechanism of in these tumors.Conclusion. Breast cancer tumors of patients with hereditary mutations in BRCA1 gene demonstrate immunosuppressive type of microenvironment and a violation of the cell death mechanism. The main directions of future therapy of these tumors may include tumor immune microenvironment modification and activation of cell death mechanisms.

Tannic Acid-Iron Complex-Based Nanoparticles as a Novel Tool against Oxidative Stress.

Accumulation of reactive oxygen species in cells leads to oxidative stress, with consequent damage for cellular components and activation of cell-death mechanisms. Oxidative stress is often associated with age-related conditions, as well as with several neurodegenerative diseases. For this reason, antioxidant molecules have attracted a lot of attention, especially those derived from natural sources—like polyphenols and tannins. The main issue related to the use of antioxidants is their inherent tendency to be oxidized, their quick enzymatic degradation in biological fluids, and their poor bioavailability. Nanomedicine, in this sense, has helped in finding new solutions to deliver and protect antioxidants; however, the concentration of the encapsulated molecule in conventional nanosystems could be very low and, therefore, less effective. We propose to exploit the properties of tannic acid, a known plant-derived antioxidant, to chelate iron ions, forming hydrophobic complexes that can be coated with a biocompatible and biodegradable phospholipid to improve stability in biological media. By combining nanoprecipitation and hot sonication procedures, we obtained three-dimensional networks composed of tannic acid–iron with a hydrodynamic diameter of ≈200 nm. These nanostructures show antioxidant properties and scavenging activity in cells after induction of an acute chemical pro-oxidant insult; moreover, they also demonstrated to counteract damage induced by oxidative stress both in vitro and on an in vivo model organism (planarians).

New perspectives in triple-negative breast cancer therapy based on treatments with TGFβ1 siRNA and doxorubicin.

Triple-negative breast cancer (TNBC), which accounts for 10-20% of all breast cancers, has the worst prognosis. Although chemotherapy treatment is a standard for TNBC, it lacks a specific target. Therefore, new therapeutic strategies are required to be investigated. In this study, a combined doxorubicin (DOX) and small interfering RNA (siRNA) therapy is proposed as therapeutic strategy for targeting TGFβ1 gene. Hs578T cell line is used as in vitro model for TNBC, wherein TGFβ1siRNA therapy is employed to enhance therapeutic effects. Cell proliferation rate is measured using an MTT test, and morphological alterations are assed using microscopically approached, while gene expression is determined by qRT-PCR analysis. The combined treatment of TGFβ1siRNA and DOX reduced levels of cell proliferation and mitochondrial activity and promoted the alteration of cell morphology (dark-field microscopy). DOX treatment caused downregulation of six genes and upregulation of another six genes. The combined effects of DOX and TGFβ1siRNA resulted in upregulation of 13 genes and downregulation of four genes. Silencing of TGFβ1 resulted in activation of cell death mechanisms in Hs578T cells, to potentiate the effects of DOX, but not in an additive manner, due to the activation of genes involved in resistance to therapy (ABCB1 and IL-6).

New Insights in Gene Expression Alteration as Effect of Paclitaxel Drug Resistance in Triple Negative Breast Cancer Cells.

Triple negative breast cancer (TNBC) is a highly aggressive form of cancer which lacks targeted therapy options. Thus, TNBC patients have poor outcomes and a decreased survival rate than patients with other types of breast cancers. Due to the lack of surface receptors, TNBC needs a comprehensive investigation to provide more information regarding patient's therapy, as well as to understand the way how to counteract drug resistance mechanisms. Nowadays, chemotherapy remains an unsolved issue which rise a lot of questions in oncology field. In this article, we investigated the implication of paclitaxel in TNBC cell lines after a prolong administration, after 12, respectively 24 passages followed by evaluation of morphological alteration, mutational pattern by next generation sequencing and the altered gene expression pattern by microarray technology and validation by qRT-PCR of the resistance to therapy relevant genes. Using functional assays, we showed that paclitaxel exhibits antiproliferative activity on Hs578T/Pax and MDA-MB-231/Pax demonstrating the activation of cell death mechanisms. Confocal microscopy revealed significant modifications which occur in the morphological structure with a disruption of the actin-filaments and also mitotic catastrophe. The presence of these nuclear alterations is due to some modifications at the cellular and molecular levels. Important alterations at the transcriptomic and genomic levels were observed from this a common drug resistance signature (IL-6, CXCL8, VEGFA, EGR1, PTGS2 and TRIB1) for both cell lines at 24 passages was discovered. Also, an important mutation (TP53) linked with drug response was identified. These results might be used to furnish novel biomarkers in TNBC, as well as to find a strategy to counteract the resistance to therapy in order to increase survival rate and to enhance the prognosis of patients with TNBC.

Influence of soil contaminated with cadmium on cell death in the digestive epithelium of soil centipede Lithobius forficatus (Myriapoda, Chilopoda)

Cadmium is a heavy metal that is treated as an environmental pollutant (air, water, soil). In order to understand the potential effects of cadmium in soil and soil invertebrates, it is important to describe all alterations which appear at different levels in organisms. The main aim of this study was to investigate, analyze and describe the alterations caused by cadmium short- and long-term intoxication at different levels in the organisms: from tissues to cells and organelles. In addition, the activation of cell death mechanisms that take part in homeostasis maintenance according to cadmium has been studied. Therefore, as the species for this project, a terrestrial and well-known widespread European species – the centipede Lithobius forficatus (Myriapoda, Chilopoda, Lithobiomorpha) – was chosen. This omnivorous species lives under upper layers of soil, under stones, litter, rocks, and leaves, and it is also commonly found in human habitats. The animals were divided into three groups: C – the control group, animals cultured in a horticultural soil; Cd1 – animals cultured in a horticultural soil supplemented with 80 mg/kg (dry weight) of CdCl2, 12 days – short-term exposure; Cd2 – animals cultured in a horticultural soil supplemented with 80 mg/kg (dry weight) of CdCl2, 45 days – long-term exposure. The midgut was isolated from each specimen and it was prepared for analysis using some histological, histochemical and immunohistochemical methods. Our studies showed that short-term intoxication causes intensification of autophagy and digestion of reserve material, while long-term exposure to this heavy metal causes activation of cell death processes together with inhibition of autophagy connected with the lack of reserve material. Additionally, we can infer that autophagy and cell death are nutrient deprivation-induced processes. Finally, we can conclude that short- and long-term exposure of soil centipede to cadmium affects different mechanisms and processes of cell death.

Nitric Oxide in Life and Death of Neutrophils.

Nitric Oxide (NO) is a key signalling molecule that has an important role in inflammation. It can be secreted by endothelial cells, neutrophils, and other cells, and once in circulation, NO plays important roles in regulating various neutrophil cellular activities and fate. To describe neutrophil cellular responses influenced by NO and its concomitant compound peroxynitrite and signalling mechanisms for neutrophil apoptosis. Literature was reviewed to assess the effects of NO on neutrophils. NO plays an important role in various neutrophil cellular activities and interaction with other cells. The characteristic cellular activities of neutrophils are adhesion and phagocytosis. NO plays a protective role in neutrophil-endothelial interaction by preventing neutrophil adhesion and endothelial cell damage by activated neutrophils. NO suppresses neutrophil phagocytic activity but stimulates longdistance contact interactions through tubulovesicular extensions or cytonemes. Neutrophils are the main source of superoxide, but NO flow results in the formation of peroxynitrite, a compound with high biological activity. Peroxynitrite is involved in the regulation of eicosanoid biosynthesis and inhibits endothelial prostacyclin synthase. NO and peroxynitrite modulate cellular 5-lipoxygenase activity and leukotriene synthesis. Long-term exposure of neutrophils to NO results in the activation of cell death mechanisms and neutrophil apoptosis. Nitric oxide and the NO/superoxide interplay fine-tune mechanisms regulating life and death in neutrophils.

Endoplasmic reticulum stress participates in the pathophysiology of mercury-caused acute kidney injury

Acute exposure to mercury chloride (HgCl2) causes acute kidney injury (AKI). Some metals interfere with protein folding, leading to endoplasmic reticulum stress (ERS), and the activation of cell death mechanisms, but in the case of mercury, there is no knowledge about whether the ERS mediates tubular damage. This study aimed to determinate if HgCl2 causes an AKI course with temporary activation of ERS and if this mechanism is involved in kidney cell death. Male mice were intoxicated with 5 mg/kg HgCl2 and sacrificed after 24, 48, 72, and 96 h of mercury administration. The kidneys of euthanized mice were used to assess the renal function, oxidative stress, redox environment, antioxidant enzymatic system, cell death, and reticulum stress markers (PERK, ATF-6, and IRE1α pathways). The results indicate temporary-dependent renal dysfunction, oxidative stress, and an increase of glutathione-dependent enzymes involved in the bioaccumulation process of mercury, as well as the enhancement of caspase 3 activity along with IRE1a, GADD-153, and caspase 12 expressions. Mercury activates the PERK/eIF2α branch during the first 48 h. Meanwhile, the activation of PERK/ATF-4 branch allowed for ATF-4, ATF-6, and IRE1α pathways to enhance GADD-153. It led to the activation of caspases 12 and 3, which mediated the deaths of the tubular and glomerular cells. This study revealed temporary-dependent ERS present during AKI caused by HgCl2, as well as how it plays a pivotal role in kidney cell damage.

Impaired Hematopoiesis and Disrupted Monocyte/Macrophage Homeostasis in Mucopolysaccharidosis Type I Mice.

Mucopolysaccharidosis type I (MPS I) is a rare autosomal recessive disease caused by alpha-L-iduronidase deficiency in which heparan and dermatan sulfate degradation is compromised. Besides primary lysosomal glycosaminoglycan accumulation, further changes in cellular functions have also been described in several murine MPS models. Herein, we evaluated alterations in hematopoiesis and its implications on the production of mature progeny in a MPS I murine model. Despite the significant increase in hematopoietic stem cells, a reduction in common myeloid progenitors and granulocyte-macrophage progenitor cells was observed in Idua -/- mice bone marrow. Furthermore, no alterations in number, viability nor activation of cell death mechanisms were observed in Idua -/- mice mature macrophages but they presented higher sensitivity to apoptotic induction after staurosporine treatment. In addition, changes in Ca(2+) signaling and a reduction in phagocytosis ability were also found. In summary, our results revealed significant intracellular changes in mature Idua -/- macrophages related to alterations in Idua -/- mice hematopoiesis, revealing a disruption in cell homeostasis. These results provide new insights into physiopathology of MPS I.

2-Hydroxypropyl-β-cyclodextrin Promotes Transcription Factor EB-mediated Activation of Autophagy

2-Hydroxypropyl-β-cyclodextrin (HPβCD) is a Food and Drug Administration-approved excipient used to improve the stability and bioavailability of drugs. Despite its wide use as a drug delivery vehicle and the recent approval of a clinical trial to evaluate its potential for the treatment of a cholesterol storage disorder, the cellular pathways involved in the adaptive response that is activated upon exposure to HPβCD are still poorly defined. Here, we show that cell treatment with HPβCD results in the activation of the transcription factor EB, a master regulator of lysosomal function and autophagy, and in enhancement of the cellular autophagic clearance capacity. HPβCD administration promotes transcription factor EB-mediated clearance of proteolipid aggregates that accumulate due to inefficient activity of the lysosome-autophagy system in cells derived from a patient with a lysosomal storage disorder. Interestingly, HPβCD-mediated activation of autophagy was found not to be associated with activation of apoptotic pathways. This study provides a mechanistic understanding of the cellular response to HPβCD treatment, which will inform the development of safe HPβCD-based therapeutic modalities and may enable engineering HPβCD as a platform technology to reduce the accumulation of lysosomal storage material.

Akutes Leberversagen – Internistische Sicht

Acute liver failure is a rare disease that can cause death in the majority of untreated cases. Sudden loss of liver function in the absence of a preexisting liver disease is considered the true form and has to be distinguished from impaired function following exacerbation of an underlying liver disease (acute or chronic failure). Common causes include acute viral hepatitis, drug induced liver injury (DILI) and toxins. The loss of the excretory and synthetic function of the liver marks the clinical presentation and results in icterus, coagulopathy and encephalopathy. Additionally impairment of renal function and sepsis occur and contribute to the high mortality of this disease. The activation of cell death mechanisms (apoptosis) leading to a reductio of viable, functional liver tissue is considered to be an important pathophysiologic mechanism. Curative therapy of this disease includes liver transplantation that has been performed in Germany for the first time in 1969. In the year 2004 a total of 91 liver transplantation were performed for acute liver failure (10.3% of all transplants) in German transplant centers.

Bcl-2 and Mn-SOD Antisense Oligodeoxynucleotides and a Glutamine-enriched Diet Facilitate Elimination of Highly Resistant B16 Melanoma Cells by Tumor Necrosis Factor-α and Chemotherapy

Mitochondrial glutathione (mtGSH) depletion increases sensitivity of Bcl-2-overexpressing B16 melanoma (B16M)-F10 cells (high metastatic potential) to tumor necrosis factor-alpha (TNF-alpha)-induced oxidative stress and death in vitro. In vivo, mtGSH depletion in B16M-F10 cells was achieved by feeding mice (where the B16M-F10 grew as a solid tumor in the footpad) with an L-glutamine (L-Gln)-enriched diet, which promoted in the tumor cells an increase in glutaminase activity, accumulation of cytosolic L-glutamate, and competitive inhibition of GSH transport into mitochondria. L-Gln-adapted B16M-F10 cells, isolated using anti-Met-72 monoclonal antibodies and flow cytometry-coupled cell sorting, were injected into the portal vein to produce hepatic metastases. In l-Gln-adapted invasive (iB16M-Gln+) cells, isolated from the liver by the same methodology and treated with TNF-alpha and an antisense Bcl-2 oligodeoxynucleotide, viability decreased to approximately 12%. iB16M-Gln+ cell death associated with increased generation of O2*- and H2O2, opening of the mitochondrial permeability transition pore complex, and release of proapoptotic molecular signals. Activation of cell death mechanisms was prevented by GSH ester-induced mtGSH replenishment. The oxidative stress-resistant survivors showed an adaptive response that includes overexpression of manganese-containing superoxide dismutase (Mn-SOD) and catalase activities. By treating iB16M-Gln+ cells with a double anti- antisense therapy (Bcl-2 and SOD2 antisense oligodeoxynucleotides) and TNF-alpha, metastatic cell survival decreased to approximately 1%. Chemotherapy (taxol plus daunorubicin) easily removed this minimum percentage of survivors. This contribution identifies critical molecules that can be sequentially targeted to facilitate elimination of highly resistant metastatic cells.