Death Receptor Pathway Of Apoptosis Research Articles

Tabersonine Induces the Apoptosis of Human Hepatocellular Carcinoma In vitro and In vivo.

Tabersonine, a natural indole alkaloid derived from Apocynaceae plants, exhibits antiinflammatory and acetylcholinesterase inhibitory activities, among other pharmacological effects. However, its anti-tumor properties and the underlying molecular mechanisms remain underexplored. The present study aims to investigate the anti-tumor effects of tabersonine and its mechanisms in inducing apoptosis in hepatocellular carcinoma. The inhibitory effects of tabersonine on the viability and proliferation of liver cancer cells were evaluated using MTT assay and colony formation assay. AO/EB, Hoechst, and Annexin V-FITC/ PI staining techniques were employed to observe cell damage and apoptosis. JC-1 staining was used to detect changes in mitochondrial membrane potential. Western blot analysis was conducted to study the anti-tumor mechanism of tabersonine on liver cancer cells. Additionally, a xenograft model using mice hepatoma HepG2 cells was established to assess the anti-tumor potency of tabersonine in vivo. Our findings revealed that tabersonine significantly inhibited cell viability and proliferation, inducing apoptosis in liver cancer cells. Treatment with tabersonine inhibited Akt phosphorylation, reduced mitochondrial membrane potential, promoted cytochrome c release from mitochondria to the cytoplasm, and increased the ratio of Bax to Bcl-2. These findings suggested that tabersonine induces apoptosis in liver cancer cells through the mitochondrial pathway. Furthermore, tabersonine treatment activated the death receptor pathway of apoptosis. In vivo studies demonstrated that tabersonine significantly inhibited xenograft tumor growth. Our study is the first to demonstrate that tabersonine induces apoptosis in HepG2 cells through both mitochondrial and death receptor apoptotic pathways, suggesting its potential as a therapeutic agent candidate for hepatic cancer.

Impacts of exposure to nanopolystyrene and/or chrysene at ambient concentrations on neurotoxicity in Siniperca chuatsi

Health risks caused by widespread environmental pollutants such as nanopolystyrene (NP) and chrysene (CHR) in aquatic ecosystems have aroused considerable concern. The present study established juvenile Mandarin fish (Siniperca chuatsi) models of NP and/or CHR exposure at ambient concentrations for 21 days to systematically investigate the underlying neurotoxicity mechanisms. The results showed that single and combined exposure to NP and CHR not only reduced the density of small neuronal cells in the grey matter layer of the optic tectum, but also induced brain oxidative stress according to physiological parameters including CAT, GSH-Px, SOD, T-AOC, and MDA. The co-exposure alleviated the histopathological damage, compared to NP and CHR single exposure group. These results indicate that NP and/or CHR causes neurotoxicity in S. chuatsi, in accordance with decreased acetylcholinesterase activity and altered expression of several marker genes of nervous system functions and development including c-fos, shha, elavl3, and mbpa. Transcriptomics analysis was performed to further investigate the potential molecular mechanisms of neurotoxicity. We propose that single NP and co-exposure induced oxidative stress activates MMP, which degrades tight junction proteins according to decreased expression of claudin, JAM, caveolin and TJP, ultimately damaging the integrity of the blood-brain barrier in S. chuatsi. Remarkably, the co-exposure exacerbated the blood-brain barrier disruption. More importantly, single NP and co-exposure induced neuronal apoptosis mainly activates the expression of apoptosis-related genes through the death receptor apoptosis pathway, while CHR acted through both death receptor apoptosis and endoplasmic reticulum apoptosis pathways. Additionally, subchronic CHR exposure caused neuroinflammation, supported by activation of TNF/NF-κB and JAK-STAT signaling pathways via targeting-related genes, while the co-exposure greatly alleviated the neuroinflammation. Collectively, our findings illuminate the underlying neurotoxicity molecular mechanisms of NP and/or CHR exposure on aquatic organisms.

Duck Tembusu virus infection induces mitochondrial-mediated and death receptor-mediated apoptosis in duck embryo fibroblasts

Duck Tembusu virus (DTMUV) is a pathogenic flavivirus that has caused enormous economic losses in Southeast Asia. Our previous study showed that DTMUV could induce duck embryo fibroblast (DEF) apoptosis, but the specific mechanism was not clear. In this study, we confirmed that DTMUV could induce the apoptosis of DEFs by DAPI staining and TUNEL staining. Furthermore, we found that the expression levels of cleaved-caspase-3/7/8/9 were significantly upregulated after DTMUV infection. After treatment of cells with an inhibitor of caspase-8 or caspase-9, DTMUV-induced apoptosis rates were significantly decreased, indicating that the caspase-8-mediated death receptor apoptotic pathway and caspase-9-mediated mitochondrial apoptotic pathway were involved in DTMUV-induced apoptosis. Moreover, we found that DTMUV infection not only caused the release of mitochondrial cytochrome C (Cyt C) and the downregulation of the apoptosis-inhibiting protein Bcl-2 but also reduced the mitochondrial membrane potential (MMP) and the accumulation of intracellular reactive oxygen species (ROS). Key genes in the mitochondrial apoptotic pathway and death receptor apoptotic pathway were upregulated to varying degrees, indicating the activation of the mitochondrial apoptosis pathway and death receptor apoptosis pathway. In conclusion, this study clarifies the molecular mechanism of DTMUV-induced apoptosis and provides a theoretical basis for revealing the pathogenic mechanism of DTMUV infection.

Citrus macroptera induces apoptosis via death receptor and mitochondrial mediated pathway as prooxidant in human non-small cell lung cancer cells

The role of plant-based prooxidants as the selective anticancer agents is of a great promise. Citrus macroptera commonly known as “Satkara”, is an important herbal and medicinal plant native to Southeast Asia. Its fruit is used in cooking different kinds of meat and pickle preparation for extra flavour and as folk medicine. In this study, the antiproliferative effect of ethyl acetate extract of C. macroptera peel (CPEA) was demonstrated on human non-small cell lung cancer cells through prooxidant induced apoptosis. Fatty acids, eight coumarins (three furanocoumarins) and one triterpenoid were identified from the CPEA through rigorous spectroscopic (UV, 1H and 13C NMR) and spectrometric (GC-MS, LC-ESI-HRMS) studies. Cytotoxicity, apoptotic rates, expression of apoptosis related genes, caspases activity and oxidative stress induced by reactive oxygen species (ROS) overproduction and mitochondrial membrane potential (MMP) damage in A549 cells were evaluated. MTT and flow cytometry analysis confirmed inhibition of A549 cell proliferation in a concentration-dependent manner with early apoptosis. qRT-PCR studies showed CPEA significantly upregulated p53, Bax, FasL, FADD and Bid mRNA expression levels and lowered Cdk1 and Bcl-2 compared to control. Caspase −9, −8 and −3 were also activated in cells treated by CPEA in both real-time and colorimetric/flurometric analysis. These results indicate that C. macroptera extract acts as prooxidant and induces cell death targeting both mitochondrial-and death receptor pathways of apoptosis in A549 cells.

Saxagliptin protects against diabetic nephropathy by inhibiting caspase 3/PARP-1-dependent nephrocyte apoptosis.

Saxagliptin (SAX) can protect against tissue damage caused by diabetic nephropathy. However, whether this compound can restore kidney function, and its specific mechanism of action remain unclear. The present study explored the therapeutic effects and mechanisms of SAX. Male Wistar rats (8 weeks old) were randomly divided into the following groups: A control group (n=10); a group with streptozocin-induced diabetes mellitus (DM) treated with saline (n=20); and a group with streptozocin-induced DM treated with SAX (n=20). Following 20 weeks of treatment, renal function and the extent of renal damage were assessed based on histological staining using hematoxylin and eosin, periodic acid-Schiff and Masson's trichrome staining. The experimental results indicated that Streptozocin induction of DM led to thicker basement membranes in mesangial cells and a more abundant extracellular matrix. These changes were ameliorated following treatment with SAX. The data demonstrated that renal tissue and renal cell apoptosis were ameliorated significantly following treatment with SAX. Furthermore, the expression levels of the apoptotic genes poly (ADP-ribose) polymerase-1 (PARP-1) and caspase 3 were significantly decreased following treatment with SAX. Therefore, SAX may reduce the extent of renal apoptosis and pathological outcomes in diabetic nephropathy by downregulating the expression of caspase 3 and PARP-1 in the death receptor pathway of apoptosis.

Aeromonas hydrophila infection activates death receptor apoptosis pathway in the red blood cells of grass carp (Ctenopharyngodon idellus)

Fish blood contains RBCs (Red blood cells) as the major cells. Unlike the absence of nucleus in mammalian RBC, fish RBC contains a nucleus. Previous researches have indicated that fish RBCs have a significant function in immune responses. However, the mechanism underlying the immune responses against bacterial infection of teleost RBCs remains enigmatic. To decipher the mechanisms, after the infection of Aeromonas hydrophila, transcriptomic profiling of grass carp RBCs was analyzed. Outcomes demonstrated that there were 2144 altogether DEGs (Differently Expressed Genes) between the A. hydrophila-infected and non-infected groups, which includes 817 up-regulated and 1327 down-regulated DEGs. Differently Expressed Genes were allocated to 45 GO terms, including 20 natural procedure terms, 14 cell related element, and 11 terms related to molecular functions. In addition, to validate our transcriptomic data, the expression levels of cytokines by Quantitative Reverse Transcription Polymerase Chain Reaction showed that they (e.g. CCL4, CCL11, CCL20, IL-4, IL-12, and IFNα) were significantly increased after A. hydrophila infection, which was identical to the expression patterns of transcriptomic data. The infection could cause the apoptosis of RBCs which was confirmed by annexin V/PI assay. To further elucidate the apoptosis pathway, the expression levels of genes by mRNA included in cellular apoptosis were monitored. The outcomes indicated that the expressions of mRNA of p53, Fas, Leucine-rich repeats, death domain-containing (LRDD) and caspase 8 were all significantly increased, respectively. Our results support the notion that A. hydrophila infection could activate Fas-related death receptor apoptosis pathway in grass carp RBCs, which will reveal another insight on the mechanisms underlying the antibacterial immunity of teleost fish RBCs.

In-vitro and in-vivo anti-breast cancer activity of synergistic effect of berberine and exercise through promoting the apoptosis and immunomodulatory effects

PurposeBreast cancer is the most common reason of cancer death in women. Berberine (BBR), a main alkaloid in Coptis chinensis, exerted anti-cancer activities. Exercise is a new immunotherapy treatment against cancer. However, it is unclear whether exercise has effects on breast cancer and whether exercise has synergistic anti-cancer effect when co-treated with BBR. Thus, it is assumed that exercise might exert an anti-cancer effect through the immune way. MethodThe anti-tumor effect of exercise and BBR in vivo was studied in mice. The MTT method, hoechst staining and cell morphology were performed to determine the synergistic effect of exercise and BBR on breast cancer in vitro. At the same time, Western blotting, intestinal microbial and SCFA detection, Q-PCR and other methods were used to study the anti-cancer molecular mechanism. ResultsThe study found that exercise and BBR co-treatment significantly slowed the progression of breast cancer in 4T1 tumor-bearing mice (p < 0.01). Compared with the TC group, the infiltration of NK cells increased in the combined group of BBR and exercise (p < 0.01), and the expression of immune factors and cytokines was also regulated. At the same time, the synergistic effect significantly increased the level of short chain fatty acids (SCFA). SCFA can promote apoptosis of 4T1 cells and change the inflammatory factors in vitro. The expression of bcl-2 and XIAP was reduced in tumor tissues, and the expression of Fas, Fadd, Bid, Cyto-C, and Caspase-3/8/9 was also increased in vitro experiments (p < 0.05). ConclusionsThese results indicate that the synergistic treatment of exercise and BBR can improve the immune system, regulate intestinal microbial metabolite (SCFA), activate the mitochondrial apoptosis pathway and Fas death receptor apoptosis pathway, and thus play an anticancer role. This may provide a new method for the treatment of breast cancer.

As3+ or/and Cu2+ exposure triggers oxidative stress imbalance, induces inflammatory response and apoptosis in chicken brain

Arsenic (As) and copper (Cu) are common environmental pollutants in nature. When they are excessively present in living organisms, they can cause heavy metal poisoning. There were relatively few studies of the toxicological concentrations of As and Cu in the brain using chicken as a model. Therefore, in this study, arsenic trioxide or/and copper sulfate were added to chicken diets for a 12-week toxicity test. The test results showed that excessive intake of As or/and Cu led to a significant reduction in the total antioxidant capacity (T-AOC), catalase (CAT) and hydroxyl radicals. And significant increase in nitric oxide synthase (NOS) indicates an imbalanced oxidation reaction. In addition, the increase in heat shock protein (HSPs), the increase of NF-κB pathway-related pro-inflammatory mediators, the change of apoptosis factors on the death receptor and mitochondrial apoptosis pathway show that, As or/and Cu exposure induced chicken brain has heat shock response (HSP), tissue inflammation and apoptosis. This damage is inseparable from the oxidative imbalance. It is worth noting that these injury changes are time-dependent, and the combined effect of these two metals is more severe than that of a single group of injuries. Our findings can inform the regulation of animal feed additives and avoid agricultural economic losses or biological health damage.

Mechanism and significance of apoptosis of the immortalized human oral mucosal epithelial cells established by Lentivirus-mediated hTERT.

During the transition from human oral mucosal epithelial cells (HOMEC) to oral squamous cell carcinoma cells (Cal27), the cells must have undergone a precancerous state. To explore the malignant rule of HOMEC, plv-HOMEC was used as a model cell for the precancerous state to investigate plv-HOMEC's apoptosis by comparing human oral mucosal epithelial cells established by Lentivirus-mediated hTERT (plv-HOMEC) with HOMEC and human Cal27. The lentiviral particles overexpressing hTERT were packaged and transfected into primary HOMEC to obtain plv-HOMEC. Expression levels of NF-κB were detected in the cytoplasm and nucleus of Cal27, plv-HOMEC and HOMEC. The level of intracellular reactive oxygen species was measured to verify the endoplasmic reticulum pathway, cytochrome C expression was detected to verify the mitochondrial pathway, and FasL gene expression was detected to verify the death receptor apoptosis pathway. The total expression of NF-κB in plv-HOMEC increased, mainly due to the greater nuclear import of NF-κB, but it was still much lower than Cal27. The endoplasmic reticulum apoptosis pathway of plv-HOMEC was not significantly affected, and there were no significant differences between them and the HOMEC cells; the mitochondrial apoptosis pathway of plv-HOMEC was inhibited, and the expression of Cyt C was very close to that of Cal27, indicating that the characteristics of plv-HOMEC are so familiar with cancer cells; the death receptor apoptosis pathway of plv-HOMEC was also inhibited, and in this apoptotic pathway, plv-HOMEC were more similar to cancer cells than to HOMEC cells. The present data suggest that NF-κB nucleation may increase in the early stage of healthy cells' carcinogenesis, followed by inhibition of the mitochondrial pathway and the death receptor apoptotic pathway.

The preparation of a cold-water soluble polysaccharide from Grifola frondosa and its inhibitory effects on MKN-45 cells.

In this study, a novel water soluble polysaccharide (named GFP-4) was extracted from Grifola frondosa at 4 oC, and its preliminary structure and inhibitory effects on human gastric carcinoma MKN-45 cells through the Fas/FasL death receptor apoptosis pathway were investigated. High-performance gel permeation chromatography (HPGPC), fourier-transform infrared spectroscopy (FT-IR), and ion chromatography (IC) results showed that GFP-4 was a 1.09 × 106 Da neutral hetero polysaccharide with pyranose rings, and α- and β-type glycosidic linkages that contained galactose, glucose, and mannose at a molar ratio of 1.00:3.45:1.19. MTT results indicated that GFP-4 significantly inhibited the proliferation of MKN-45 cells in a concentration-dependent manner. The H&E staining and Hoechst 33342/PI double staining results showed that GFP-4-treated MKN-45 cells were subjected to underwent typical apoptotic morphologic changes such as nuclear pyknosis, chromatin condensation, and an increase of membrane permeability. Annexin V-FITC/PI double staining, cell cycle analysis, and western blot results revealed the GFP-4 induced MKN-45 cells apoptosis through the Fas/FasL-mediated death receptor pathway with cells arrested at the G0/G1 phase. These data indicate that GFP-4 is a promising candidate for treating gastric cancer and provide a theoretical basis for the future development and utilization of G. frondosa clinically.

Anticancer potentiality and mode of action of low-carbohydrate proteins and peptides from mushrooms.

Severe side effects of chemotherapy as well as drug resistance highlight the ongoing need to discover novel natural bioactive compounds with anticancer potentiality. Mushroom-derived proteins are among the naturally occurring compounds that have been the subject of a body of research on their potentiality in cancer therapy. The greatest attention in relevant review articles has been paid to well-known mushroom-derived glycoproteins such as lectins and protein-bound polysaccharide complexes such as polysaccharide-K (PSK) or krestin and polysaccharopeptide (PSP), which contain substantial amounts of carbohydrates (50-90%). These complex compounds exert their anticancer activity mainly by binding to cell membranes leading to extrinsic (death receptor) apoptosis or intrinsic (mitochondrial) apoptotic pathways. However, several other research studies have reported pure, well-characterized, proteins or peptides from mushrooms, which are carbohydrate-free or have very low amounts of carbohydrate. These proteins may fall into four categories including fungal immunomodulatory proteins, ubiquitin-like proteins, enzymes, and unclassified proteins. Well-defined chemical structure, elucidated full amino acid or N-terminal sequences, purity, and having some distinct and specific pathways compared to glycoproteins have made these low-carbohydrate proteins attractive for cancer research. The aim of this review was therefore to improve the current understanding of mushroom-derived low-carbohydrate proteins and to consolidate the existing knowledge of the most promising mushroom species from which low-carbohydrate proteins have been derived, characterized, and examined for their anticancer activity. In addition, molecular targets and mechanisms of action of these proteins have been discussed. Key points • Mushroom-derived low-carbohydrate proteins lack or have low carbohydrate. • Low-carbohydrate proteins show potent anticancer activities in vitro and in vivo. • There are specific pathways for low-carbohydrate proteins to inhibit cancer cells.

Novel Frog Skin-Derived Peptide Dermaseptin-PP for Lung Cancer Treatment: In vitro/vivo Evaluation and Anti-tumor Mechanisms Study.

Lung cancer is the major cause of cancer deaths worldwide, and it has the highest incidence and mortality rate of any cancer among men and women in China. The first-line therapy for lung cancer treatment is platinum-based chemotherapy drugs such as cisplatin. However, the application of present chemotherapies is limited by severe side effects, which stimulates the discovery of new drugs with new anti-tumor mechanisms and fewer side effects. Beneficially, many antimicrobial peptides (AMPs) from frog skin have been reported to exhibit potent anti-cancer activities with low toxicity, high selectivity and a low propensity to induce resistance. In this study, we first reported an AMP named Dermaseptin-PP, from a rarely studied frog species, Phyllomedusa palliata. Dermaseptin-PP exhibited selective cytotoxicity on H157, MCF-7, PC-3, and U251 MG cancer cells instead of normal HMEC-1 cells with low hemolytic effect. Furthermore, on subcutaneous H157 tumor model of nude mice, Dermaseptin-PP was found to display potent in vivo anti-tumor activity in a dose-related manner without obvious hepatopulmonary side effects. It is widely accepted that AMPs usually work through a membrane disruptive mode, and the confocal laser microscope observation confirmed that Dermaseptin-PP could destroy H157 cell membranes. Further investigation of mechanisms by flow cytometry assay and immunohistochemical analysis unraveled that Dermaseptin-PP also exerted its anti-tumor activity by inducing H157 cell apoptosis via both endogenous mitochondrial apoptosis pathway and exogenous death receptor apoptosis pathway. Herein, we emphasize that the membrane disrupting and the apoptosis activation effects of Dermaseptin-PP both depend on its concentration. Overall, a novel frog skin-derived AMP, named Dermaseptin-PP, was identified for the first time. It possesses strong antimicrobial activity and effective anti-tumor activity by distinct mechanisms. This study revealed the possibility of Dermaseptin-PP for lung cancer treatment and provided a new perspective for designing novel AMP-based anti-tumor candidates with low risk of cytotoxicity.

Apoptosis Exerts a Vital Role in the Treatment of Colitis-Associated Cancer by Herbal Medicine.

Colitis-associated cancer (CAC) is known as inflammatory bowel disease (IBD)-developed colorectal cancer, the pathogenesis of which involves the occurrence of apoptosis. Western drugs clinically applied to CAC are often single-targeted and exert many adverse reactions after long-term administration, so it is urgent to develop new drugs for the treatment of CAC. Herbal medicines commonly have multiple components with multiple targets, and most of them are low-toxicity. Some herbal medicines have been reported to ameliorate CAC through inducing apoptosis, but there is still a lack of systematic review. In this work, we reviewed articles published in Sci Finder, Web of Science, PubMed, Google Scholar, CNKI, and other databases in recent years by setting the keywords as apoptosis in combination with colitis-associated cancer. We summarized the herbal medicine extracts or their compounds that can prevent CAC by modulating apoptosis and analyzed the mechanism of action. The results show the following. (1) Herbal medicines regulate both the mitochondrial apoptosis pathway and death receptor apoptosis pathway. (2) Herbal medicines modulate the above two apoptotic pathways by affecting signal transductions of IL-6/STAT3, MAPK/NF-κ B, Oxidative stress, Non-canonical TGF-β1, WNT/β-catenin, and Cell cycle, thereby ameliorating CAC. We conclude that following. (1) Studies on the role of herbal medicine in regulating apoptosis through the Ras/Raf/ERK, WNT/β-catenin, and Cell cycle pathways have not yet been carried out in sufficient depth. (2) The active constituents of reported anti-CAC herbal medicine mainly include polyphenols, terpenoids, and saccharide. Also, we identified other herbal medicines with the constituents mentioned above as their main components, aiming to provide a reference for the clinical use of herbal medicine in the treatment of CAC. (3) New dosage forms can be utilized to elevate the targeting and reduce the toxicity of herbal medicine.

Smac mimetic promotes TNF-α to induce apoptosis of gallbladder carcinoma cells

Gallbladder carcinoma has a high degree of malignancy. No effective treatment exists for patients with advanced tumors. The second mitochondria-derived activator of caspases (Smac) is the antagonist of the inhibitors of apoptosis protein. Smac mimetics are a class of effective tumor-targeted drugs undergoing clinical trials. However, studies on the effect of Smac mimetics on gallbladder cancer are unavailable. In this study, Smac mimetics can promote tumor necrosis factor-α (TNF-α) to inhibit the proliferation of gallbladder cancer cells and activate the apoptotic pathway, thereby promoting the ubiquitination of Lys48 on Receptor interacting protein kinase-1 (RIPK1) and leading to proteasomal degradation that causes damage to RIPK1 protein integrity. The formation of complex I (RIPK1, tumor necrosis factor 1-associated death domain protein, and TNF receptor-associated factor 2) is inhibited. Then, nonubiquitinated RIPK1 binds with the Fas-associated death domain and caspase-8 to form complex II and promotes the death receptor pathway of apoptosis. Animal experiments further verify that TNF-α combined with Smac mimetics can inhibit the growth of transplanted tumors and induce the apoptosis of transplanted tumor cells. This research provides a new direction for the targeted therapy of gallbladder cancer.

Alterations of antioxidant indexes and inflammatory cytokine expression aggravated hepatocellular apoptosis through mitochondrial and death receptor-dependent pathways in Gallus gallus exposed to arsenic and copper.

In this study, we sought to investigate the effects of sub-chronic exposure of arsenic (As) and copper (Cu) on oxidative stress, inflammatory response, and mitochondria and death receptor apoptosis pathways in chicken liver. Seventy-two 1-day-old male Hy-line chickens were treated with basal diet, 30mg/kg arsenic trioxide (As2O3), or/and 300mg/kg copper sulfate (CuSO4) for 4, 8, and 12weeks. Study revealed that exposure to As or/and Cu undermined the antioxidant function and increased lipid peroxidation. Worse yet, liver cell swollen, vacuolar degeneration, and inflammatory cell infiltration were accompanied by an increase of the nuclear factor-κB (NF-κB) and its downstream inflammation-related genes after exposure to As or/and Cu. Furthermore, mitochondria swollen and chromatin condensation were found in As and Cu groups, and hepatocyte nuclear membrane rupture and markedly increased (P< 0.01) apoptosis index were observed in As combined with Cu group. Meanwhile, the transcription and protein expression levels of Bcl-2-associated X protein (Bax), p53, cytochrome c (Cyt c), and caspase-3, 8, 9 were upregulated and B cell lymphoma-2 (Bcl-2) was downregulated in As, Cu, and As + Cu groups in the liver tissues (P< 0.05, P< 0.01). Our results indicated that exposure to As or/and Cu could lead to oxidative stress, inflammatory response, and tissue damage and aggravate hepatocellular apoptosis through mitochondrial and death receptor-dependent pathways in chicken liver. And As and Cu showed a possible synergistic relationship in liver damage.

Subchronic arsenism-induced oxidative stress and inflammation contribute to apoptosis through mitochondrial and death receptor dependent pathways in chicken immune organs.

In many organ dysfunctions, arsenic and its compounds are well known to induce apoptosis by the mitochondria and death receptor apoptotic pathways in liver and airway. However, it is less reported that which signaling pathways contribute to excessive apoptosis of chicken immune organs, a major target of toxic metals biotransformation, which suffer from subchronic arsenism. In this study, we investigated whether the mitochondria or death receptor apoptotic pathways activated in the immune organs (spleen, thymus and bursa of Fabricius) of one-day-old male Hy-line chickens exposed to arsenic trioxide (As2O3), which were fed on diets supplemented with 0, 0.625, 1.25 and 2.5 mg/kg BW of As2O3 for 30, 60 and 90 days. We found that (1) Oxidative damage and inflammatory response were confirmed in the immune organs of chickens fed on As2O3 diet. (2) Subchronic arsenism induced typical apoptotic changes in ultrastructure. (3) TdT-mediated dUTP Nick-End Labeling (TUNEL) showed that the number of apoptotic cells significantly increased under subchronic arsenism. (4) As2O3-induced apoptosis of immune organs involved in mitochondrial pathway (decrease of B-cell lymphoma-2 (Bcl-2) and increase of protein 53 (p53), Bcl-2 Associated X Protein (Bax), caspase-9, caspase-3) and death receptor pathway (increase of factor associated suicide (Fas) and caspase-8). In conclusion, this work is the first to demonstrate that the activation of mitochondria and death receptor apoptosis pathways can lead to excessive apoptosis in immune organs of chickens, which suffer from subchronic arsenism, meanwhile, oxidative stress as well as subsequent inflammatory is a crucial driver of apoptosis.

Inhibition of G9a attenuates cell proliferation via the mitochondrial apoptosis pathway in lung adenocarcinoma

Objective: The aim of this study is to investigate the effect of G9a inhibitor BIX-01294 on attenuating cell proliferation in human lung adenocarcinoma A549 cell line and the underlying molecular mechanism. Methods: Treated with BIX-01294, the growth and proliferation of A549 cells were detected by MTT assay and colony formation assay, and its impact on cell apoptosis was analyzed using flow cytometry. By Western blot, we explored the alterations in the expression of apoptosis-related proteins and the G9a catalysate, H3K9me and H3K9me2. In addition, in the pretreatment with caspase inhibitor Z-VAD-FMK, we detected the apoptotic dependence of BIX-01294 attenuating impact on A549 cell proliferation. Results: Compared with the control group, the histone methyltransferase G9a inhibitor BIX-01294 attenuated cell proliferation in A549 cells in a dose- and time-dependent manner. There were 42.5±8.7 colonies after BIX-01294 (10 μmol/L) treatment for 7 days, while 172.7±23.0 colonies in the control group, with a statistical significance (P<0.05). After treatment with BIX-01294 (10 μmol/L) for 24 hours, the cell apoptotic rate was(47.6±8.4)%, with a significant difference in comparison with the control group [(7.2±3.6)%, P<0.05]. The expression of G9a catalysate, H3K9me and H3K9me2 was downregulated, the same with anti-apoptotic protein Bcl-2, while the proteins in mitochondrial apoptosis pathway, Bax, Bak and cleaved caspase-9, were upregulated, so was the expression of cleaved caspase-3 and cleaved PARP, and there was no alteration in the expression of cleaved caspase-8, which is a protein related with death receptor apoptosis pathway. Furthermore, after Z-VAD-FMK pretreatment, the cell apoptotic rate was decreased significantly, and the expression of apoptosis-related proteins were downregulated. Conclusions: Our results indicate that BIX-01294 can attenuate cell proliferation in lung adenocarcinoma, and it can be considered as one of the underlying mechanisms, the apoptosis may be induced by activating mitochondrial pathway.

The Ganglioside GM-1 Inhibits Bupivacaine-Induced Neurotoxicity in Mouse Neuroblastoma Neuro2a Cells.

Studies indicate that bupivacaine-induced neurotoxicity results from apoptosis. Gangliosides have been shown to promote neuronal repair and recovery of neurological function after spinal cord injury. Previously, we confirmed that in vivo administration of the ganglioside GM-1 attenuated bupivacaine-induced neurotoxicity in various animal models; however, the underlying mechanism remains unclear. Cells of the neuroblastoma line N2a (Neuro2a cells) were divided into three experimental groups: control, bupivacaine-treated, and bupivacaine-treated with GM-1 pretreatment. Cell viability and apoptosis were assessed through CCK-8 assays, Hoechst staining, and flow cytometry analysis of Annexin-V/propidium iodide double labeling. Real-time polymerase chain reaction and western blotting assessed the expression of caspase-3, caspase-8, and caspase-9. Bupivacaine-induced apoptosis worsened with increasing dose and exposure time. Bupivacaine induced increased expression of caspase-3 and caspase-9, but not caspase-8, indicating that the mitochondrial pathway but not the death receptor apoptosis pathway was activated. GM-1 pretreatment inhibited bupivacaine-induced apoptosis and the expression of caspase-3 and caspase-9 in a dose-dependent manner. Bupivacaine induced neurotoxicity by activating apoptosis via the mitochondrial pathway, and this was inhibited by GM-1 pretreatment.

Iso-suillin from Suillus flavus Induces Apoptosis in Human Small Cell Lung Cancer H446 Cell Line.

Background:The suillin isoform iso-suillin is a natural substance isolated from a petroleum ether extract of the fruiting bodies of the mushroom Suillus flavus. Previous studies have found its inhibition effect on some cancer cells, and we aimed to study its effects on human small cell lung cancer H446 cell line.Methods:Cell viability was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Cellular morphological changes (apoptosis and necrosis) were evaluated using an electron microscope and Hoechst 33258 staining detected by the inverted microscope. Flow cytometry was used to detect cell apoptosis, cell cycle distribution, and mitochondrial membrane potential. Protein expression was determined by Western blotting analysis.Results:Here, we describe the ability of iso-suillin to inhibit the growth of H446 cells in time- and dose-dependent way. Iso-suillin had no obvious impact on normal human lymphocyte proliferation at low concentrations (9.09, 18.17, or 36.35 μmol/L) but promoted lymphocyte proliferation at a high concentration (72.70 μmol/L). After treatment of different concentrations of iso-suillin (6.82, 13.63, or 20.45 μmol/L), the apoptosis rate of H446 cells increased with increasing concentrations of iso-suillin (16.70%, 35.54%, and 49.20%, respectively, all P < 0.05 compared with the control), and the expression of related apoptotic proteins in the mitochondrial pathway including cytochrome c and caspase-9 were up-regulated compared with the control (all P < 0.05). On the contrary, Bcl-2/Bax ratio was down-regulated compared with the control. Besides, the expression of pro-apoptotic proteins in the death receptor apoptosis pathway, including Fas-associating protein with a novel death domain and caspase-8, and the expression of caspase-3, a downstream regulatory protein of apoptosis, were also increased compared with the control (all P < 0.05). Inhibitors of caspase-9 and caspase-8 reversed the apoptosis process in H446 cells to varying degrees.Conclusions:These results suggest that iso-suillin could induce H446 cell apoptosis through the mitochondrial pathway and the death-receptor pathway. Therefore, iso-suillin might have a potential application as a novel drug for lung cancer treatment.

The fungicide thiabendazole causes apoptosis in rat hepatocytes

Many pharmaceutical drugs cause hepatotoxicity in humans leading to severe liver diseases, representing a serious public health issue. This study investigates the ability of the anthelmintic and antifungal drug thiabendazole to cause cell death by apoptosis and metabolic changes in primary cultures of rat hepatocytes. Thiabendazole (200–500μM) induced apoptosis in hepatocytes after 1 to 24h, causing loss of mitochondrial membrane potential, cytochrome c release from mitochondria, Fas-associated death domain (FADD) translocation from the cytosol to membranes, and activation of caspases-3, -8 and -9. Thus, thiabendazole activated both the mitochondrial and death receptor pathways of apoptosis. Under these conditions, cell death by necrosis was not detected following exposure to thiabendazole (100–500μM) for 24–48h, measured by lactate dehydrogenase release and propidium iodide uptake. Furthermore, thiabendazole increased activities of cytochrome P450 (CYP) isoenzymes CYP1A and CYP2B after 24 and 48h, determined by 7-ethoxyresorufin-O-deethylase (EROD) and 7-pentoxyresorufin-O-dealkylase (PROD) activities, respectively. An important finding is that thiabendazole can eliminate hepatocytes by apoptosis, which could be a sensitive marker for hepatic damage and cell death. This study improves understanding of the mode of cell death induced by thiabendazole, which is important given that humans and animals are exposed to this compound as a pharmaceutical agent and in an environmental context.