Delayed cell death associated with mitotic catastrophe in γ-irradiated stem-like glioma cells

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Firat, Elke; Gaedicke, Simone; Tsurumi, Chizuko; Esser, Norbert; Weyerbrock, Astrid; Niedermann, Gabriele

2011-01-01

Stem-like tumor cells are regarded as highly resistant to ionizing radiation (IR). Previous studies have focused on apoptosis early after irradiation, and the apoptosis resistance observed has been attributed to reduced DNA damage or enhanced DNA repair compared to non-stem tumor cells. Here, early and late radioresponse of patient-derived stem-like glioma cells (SLGCs) and differentiated cells directly derived from them were examined for cell death mode and the influence of stem cell-specific growth factors. Primary SLGCs were propagated in serum-free medium with the stem-cell mitogens epidermal growth factor (EGF) and fibroblast growth factor-2 (FGF-2). Differentiation was induced by serum-containing medium without EGF and FGF. Radiation sensitivity was evaluated by assessing proliferation, clonogenic survival, apoptosis, and mitotic catastrophe. DNA damage-associated γH2AX as well as p53 and p21 expression were determined by Western blots. SLGCs failed to apoptose in the first 4 days after irradiation even at high single doses up to 10 Gy, but we observed substantial cell death later than 4 days postirradiation in 3 of 6 SLGC lines treated with 5 or 10 Gy. This delayed cell death was observed in 3 of the 4 SLGC lines with nonfunctional p53, was associated with mitotic catastrophe and occurred via apoptosis. The early apoptosis resistance of the SLGCs was associated with lower γH2AX compared to differentiated cells, but we found that the stem-cell culture cytokines EGF plus FGF-2 strongly reduce γH2AX levels. Nonetheless, in two p53-deficient SLGC lines examined γIR-induced apoptosis even correlated with EGF/FGF-induced proliferation and mitotic catastrophe. In a line containing CD133-positive and -negative stem-like cells, the CD133-positive cells proliferated faster and underwent more γIR-induced mitotic catastrophe. Our results suggest the importance of delayed apoptosis, associated mitotic catastrophe, and cellular proliferation for γIR-induced death of

Dynamin inhibitors induce caspase-mediated apoptosis following cytokinesis failure in human cancer cells and this is blocked by Bcl-2 overexpression

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Braithwaite Antony W

2011-06-01

Full Text Available Abstract Background The aim of both classical (e.g. taxol and targeted anti-mitotic agents (e.g. Aurora kinase inhibitors is to disrupt the mitotic spindle. Such compounds are currently used in the clinic and/or are being tested in clinical trials for cancer treatment. We recently reported a new class of targeted anti-mitotic compounds that do not disrupt the mitotic spindle, but exclusively block completion of cytokinesis. This new class includes MiTMAB and OcTMAB (MiTMABs, which are potent inhibitors of the endocytic protein, dynamin. Like other anti-mitotics, MiTMABs are highly cytotoxic and possess anti-proliferative properties, which appear to be selective for cancer cells. The cellular response following cytokinesis failure and the mechanistic pathway involved is unknown. Results We show that MiTMABs induce cell death specifically following cytokinesis failure via the intrinsic apoptotic pathway. This involves cleavage of caspase-8, -9, -3 and PARP, DNA fragmentation and membrane blebbing. Apoptosis was blocked by the pan-caspase inhibitor, ZVAD, and in HeLa cells stably expressing the anti-apoptotic protein, Bcl-2. This resulted in an accumulation of polyploid cells. Caspases were not cleaved in MiTMAB-treated cells that did not enter mitosis. This is consistent with the model that apoptosis induced by MiTMABs occurs exclusively following cytokinesis failure. Cytokinesis failure induced by cytochalasin B also resulted in apoptosis, suggesting that disruption of this process is generally toxic to cells. Conclusion Collectively, these data indicate that MiTMAB-induced apoptosis is dependent on both polyploidization and specific intracellular signalling components. This suggests that dynamin and potentially other cytokinesis factors are novel targets for development of cancer therapeutics.

Arsenic trioxide induced rhabdomyolysis, a rare but severe side effect, in an APL patient: a case report.

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He, Haiyan; An, Ran; Hou, Jian; Fu, Weijun

2017-06-01

Arsenic trioxide (ATO), a component of the traditional Chinese medicine arsenic sublimate, promotes apoptosis and induces leukemic cell differentiation. Combined with all-trans-retinotic acid (ATRA), ATO has become the first-line induction therapy in treating acute promyelocytic leukemia (APL). The most common side effects of ATO include hepatotoxicity, gastrointestinal symptoms, water-sodium retention, and nervous system damage. In this report, we present a rare side effect, rhabdomyolysis, in a 68-year-old female APL patient who was treated with ATO. After taking 10 mg ATO daily for 6 days, she presented shortness of breath, myodynia, elevated creatine kinase, and acute renal insufficiency. This report describes the first case of ATO-induced rhabdomyolysis.

Carbon-ion beam irradiation kills X-ray-resistant p53-null cancer cells by inducing mitotic catastrophe.

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Napapat Amornwichet

Full Text Available BACKGROUND AND PURPOSE: To understand the mechanisms involved in the strong killing effect of carbon-ion beam irradiation on cancer cells with TP53 tumor suppressor gene deficiencies. MATERIALS AND METHODS: DNA damage responses after carbon-ion beam or X-ray irradiation in isogenic HCT116 colorectal cancer cell lines with and without TP53 (p53+/+ and p53-/-, respectively were analyzed as follows: cell survival by clonogenic assay, cell death modes by morphologic observation of DAPI-stained nuclei, DNA double-strand breaks (DSBs by immunostaining of phosphorylated H2AX (γH2AX, and cell cycle by flow cytometry and immunostaining of Ser10-phosphorylated histone H3. RESULTS: The p53-/- cells were more resistant than the p53+/+ cells to X-ray irradiation, while the sensitivities of the p53+/+ and p53-/- cells to carbon-ion beam irradiation were comparable. X-ray and carbon-ion beam irradiations predominantly induced apoptosis of the p53+/+ cells but not the p53-/- cells. In the p53-/- cells, carbon-ion beam irradiation, but not X-ray irradiation, markedly induced mitotic catastrophe that was associated with premature mitotic entry with harboring long-retained DSBs at 24 h post-irradiation. CONCLUSIONS: Efficient induction of mitotic catastrophe in apoptosis-resistant p53-deficient cells implies a strong cancer cell-killing effect of carbon-ion beam irradiation that is independent of the p53 status, suggesting its biological advantage over X-ray treatment.

Molecular mechanism of X-ray-induced p53-dependent apoptosis

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Nakano, Hisako [Tokyo Metropolitan Inst. of Medical Center (Japan)

1999-03-01

Radiation-induced cell death has been classified into the interphase- and mitotic-ones, both of which apoptosis involving. This review described the molecular mechanism of the apoptosis, focusing on its p53-dependent process. It is known that there are genes regulating cell death either negatively or positively and the latter is involved in apoptosis. As an important factor in the apoptosis, p53 has become remarkable since it was shown that X-ray-induced apoptosis required RNA and protein syntheses in thymocytes and those cells of p53 gene-depleted mouse were shown to be resistant to gamma-ray-induced apoptosis. Radiation sensitivity of MOLT-4 cells derived from human T cell leukemia, exhibiting the typical X-ray-induced p53-dependent apoptosis, depends on the levels of p53 mRNA and protein. p53 is a gene suppressing tumor and also a transcription factor. Consequently, mutation of p53 conceivably leads to the failure of cell cycle regulation, which allows damaged cells to divide without both repair and exclusion due to loss of the apoptotic mechanism, and finally results in carcinogenesis. The radiation effect occurs in the order of the cell damage, inhibition of p53-Mdm2 binding, accumulation of p53, activation of mdm2 transcription, Mdm2 accumulation, p53-protein degradation and recovery to the steady state level. Here, the cystein protease (caspases) plays an important role as a disposing mechanism for cells scheduled to die. However, many are unknown to be solved in future. (K.H.) 119 refs.

ATP depletion during mitotic arrest induces mitotic slippage and APC/CCdh1-dependent cyclin B1 degradation.

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Park, Yun Yeon; Ahn, Ju-Hyun; Cho, Min-Guk; Lee, Jae-Ho

2018-04-27

ATP depletion inhibits cell cycle progression, especially during the G1 phase and the G2 to M transition. However, the effect of ATP depletion on mitotic progression remains unclear. We observed that the reduction of ATP after prometaphase by simultaneous treatment with 2-deoxyglucose and NaN 3 did not arrest mitotic progression. Interestingly, ATP depletion during nocodazole-induced prometaphase arrest resulted in mitotic slippage, as indicated by a reduction in mitotic cells, APC/C-dependent degradation of cyclin B1, increased cell attachment, and increased nuclear membrane reassembly. Additionally, cells successfully progressed through the cell cycle after mitotic slippage, as indicated by EdU incorporation and time-lapse imaging. Although degradation of cyclin B during normal mitotic progression is primarily regulated by APC/C Cdc20 , we observed an unexpected decrease in Cdc20 prior to degradation of cyclin B during mitotic slippage. This decrease in Cdc20 was followed by a change in the binding partner preference of APC/C from Cdc20 to Cdh1; consequently, APC/C Cdh1 , but not APC/C Cdc20 , facilitated cyclin B degradation following ATP depletion. Pulse-chase analysis revealed that ATP depletion significantly abrogated global translation, including the translation of Cdc20 and Cdh1. Additionally, the half-life of Cdh1 was much longer than that of Cdc20. These data suggest that ATP depletion during mitotic arrest induces mitotic slippage facilitated by APC/C Cdh1 -dependent cyclin B degradation, which follows a decrease in Cdc20 resulting from reduced global translation and the differences in the half-lives of the Cdc20 and Cdh1 proteins.

Arsenic induced apoptosis in rat liver following repeated 60 days exposure

International Nuclear Information System (INIS)

Bashir, Somia; Sharma, Yukti; Irshad, M.; Nag, T.C.; Tiwari, Monica; Kabra, M.; Dogra, T.D.

2006-01-01

Background: Accumulation of the wide spread environmental toxin arsenic in liver results in hepatotoxcity. Exposure to arsenite and other arsenicals has been previously shown to induce apoptosis in certain tumor cell lines at low (1-3 μM) concentration. Aim: The present study was focused to elucidate the role of free radicals in arsenic toxicity and to investigate the nature of in vivo sodium arsenite induced cell death in liver. Methods: Male wistar rats were exposed to arsenite at three different doses of 0.05, 2.5 and 5 mg/l for 60 days. Oxidative stress in liver was measured by estimating pro-oxidant and antioxidant activity in liver. Histopathological examination of liver was carried out by light and transmission electron microscopy. Analysis of DNA fragmentation by gel electrophoresis was used to identify apoptosis after the exposure. Terminal deoxy-nucleotidyl transferase mediated dUTP Nick end-labeling (TUNEL) assay was used to qualify and quantify apoptosis. Results: A significant increase in cytochrome-P450 and lipid peroxidation accompanied with a significant alteration in the activity of many of the antioxidants was observed, all suggestive of arsenic induced oxidative stress. Histopathological examination under light and transmission electron microscope suggested a combination of ongoing necrosis and apoptosis. DNA-TUNEL showed an increase in apoptotic cells in liver. Agarose gel electrophoresis of DNA of hepatocytes resulted in a characteristic ladder pattern. Conclusion: Chronic arsenic administration induces a specific pattern of apoptosis called post-mitotic apoptosis

Sensitivity to sodium arsenite in human melanoma cells depends upon susceptibility to arsenite-induced mitotic arrest

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McNeely, Samuel C.; Belshoff, Alex C.; Taylor, B. Frazier; Fan, Teresa W-M.; McCabe, Michael J.; Pinhas, Allan R.

2008-01-01

Arsenic induces clinical remission in patients with acute promyelocytic leukemia and has potential for treatment of other cancers. The current study examines factors influencing sensitivity to arsenic using human malignant melanoma cell lines. A375 and SK-Mel-2 cells were sensitive to clinically achievable concentrations of arsenite, whereas SK-Mel-3 and SK-Mel-28 cells required supratherapeutic levels for toxicity. Inhibition of glutathione synthesis, glutathione S-transferase (GST) activity, and multidrug resistance protein (MRP) transporter function attenuated arsenite resistance, consistent with studies suggesting that arsenite is extruded from the cell as a glutathione conjugate by MRP-1. However, MRP-1 was not overexpressed in resistant lines and GST-π was only slightly elevated. ICP-MS analysis indicated that arsenite-resistant SK-Mel-28 cells did not accumulate less arsenic than arsenite-sensitive A375 cells, suggesting that resistance was not attributable to reduced arsenic accumulation but rather to intrinsic properties of resistant cell lines. The mode of arsenite-induced cell death was apoptosis. Arsenite-induced apoptosis is associated with cell cycle alterations. Cell cycle analysis revealed arsenite-sensitive cells arrested in mitosis whereas arsenite-resistant cells did not, suggesting that induction of mitotic arrest occurs at lower intracellular arsenic concentrations. Higher intracellular arsenic levels induced cell cycle arrest in the S-phase and G 2 -phase in SK-Mel-3 and SK-Mel-28 cells, respectively. The lack of arsenite-induced mitotic arrest in resistant cell lines was associated with a weakened spindle checkpoint resulting from reduced expression of spindle checkpoint protein BUBR1. These data suggest that arsenite has potential for treatment of solid tumors but a functional spindle checkpoint is a prerequisite for a positive response to its clinical application

Arsenic trioxide: impact on the growth and differentiation of cancer cells and possible use in cancer therapy

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Ewelina Hoffman

2013-08-01

Full Text Available Arsenic trioxide (As2O3 has recently been identified as an effective drug in different types of cancer therapy. It is a useful pharmacological agent in acute promyelocytic leukemia (APL treatment, especially the form that is resistant to conventional chemotherapy with all-trans retinoic acid (ATRA. What is more, laboratory data suggest that As2O3 is also active when it comes to several solid tumor cell lines. However, the mechanism of action is not fully understood. As2O3 in high doses triggers apoptosis, while in lower concentrations it induces partial differentiation. The As2O3 mechanism of action involves effects on mitochondrial transmembrane potential which lead to apoptosis. It also acts on the activity of JNK kinase, glutathione, caspases, NF-ĸB nuclear factor or pro- and antiapoptotic proteins. This publication presents the current knowledge about the influence of arsenic trioxide in cancer cells.

Exposure of Human Lung Cancer Cells to 8-Chloro-Adenosine Induces G2/M Arrest and Mitotic Catastrophe

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Hong-Yu Zhang

2004-11-01

Full Text Available 8-Chloro-adenosine (8-CI-Ado is a potent chemotherapeutic agent whose cytotoxicity in a variety of tumor cell lines has been widely investigated. However, the molecular mechanisms are uncertain. In this study, we found that exposure of human lung cancer cell lines A549 (p53-wt and H1299 (p53-depleted to 8-CI-Ado induced cell arrest in the G2/M phase, which was accompanied by accumulation of binucleated and polymorphonucleated cells resulting from aberrant mitosis and failed cytokinesis. Western blotting showed the loss of phosphorylated forms of Cdc2 and Cdc25C that allowed progression into mitosis. Furthermore, the increase in Ser10-phosphorylated histone H3-positive cells revealed by fluorescence-activated cell sorting suggested that the agent-targeted cells were able to exit the G2 phase and enter the M phase. Immunocytochemistry showed that microtubule and microfilament arrays were changed in exposed cells, indicating that the dynamic instability of microtubules and microfilaments was lost, which may correlate with mitotic dividing failure. Aberrant mitosis resulted in mitotic catastrophe followed by varying degrees of apoptosis, depending on the cell lines. Thus, 8-CI-Ado appears to exert its cytotoxicity toward cells in culture by inducing mitotic catastrophe.

Restraint of apoptosis during mitosis through interdomain phosphorylation of caspase-2

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Andersen, Joshua L; Johnson, Carrie E; Freel, Christopher D; Parrish, Amanda B; Day, Jennifer L; Buchakjian, Marisa R; Nutt, Leta K; Thompson, J Will; Moseley, M Arthur; Kornbluth, Sally

2009-01-01

The apoptotic initiator caspase-2 has been implicated in oocyte death, in DNA damage- and heat shock-induced death, and in mitotic catastrophe. We show here that the mitosis-promoting kinase, cdk1–cyclin B1, suppresses apoptosis upstream of mitochondrial cytochrome c release by phosphorylating caspase-2 within an evolutionarily conserved sequence at Ser 340. Phosphorylation of this residue, situated in the caspase-2 interdomain, prevents caspase-2 activation. S340 was susceptible to phosphatase 1 dephosphorylation, and an interaction between phosphatase 1 and caspase-2 detected during interphase was lost in mitosis. Expression of S340A non-phosphorylatable caspase-2 abrogated mitotic suppression of caspase-2 and apoptosis in various settings, including oocytes induced to undergo cdk1-dependent maturation. Moreover, U2OS cells treated with nocodazole were found to undergo mitotic catastrophe more readily when endogenous caspase-2 was replaced with the S340A mutant to lift mitotic inhibition. These data demonstrate that for apoptotic stimuli transduced by caspase-2, cell death is prevented during mitosis through the inhibitory phosphorylation of caspase-2 and suggest that under conditions of mitotic arrest, cdk1–cyclin B1 activity must be overcome for apoptosis to occur. PMID:19730412

Paclitaxel-induced apoptosis is BAK-dependent, but BAX and BIM-independent in breast tumor.

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Anna V Miller

Full Text Available Paclitaxel (Taxol-induced cell death requires the intrinsic cell death pathway, but the specific participants and the precise mechanisms are poorly understood. Previous studies indicate that a BH3-only protein BIM (BCL-2 Interacting Mediator of cell death plays a role in paclitaxel-induced apoptosis. We show here that BIM is dispensable in apoptosis with paclitaxel treatment using bim(-/- MEFs (mouse embryonic fibroblasts, the bim(-/- mouse breast tumor model, and shRNA-mediated down-regulation of BIM in human breast cancer cells. In contrast, both bak (-/- MEFs and human breast cancer cells in which BAK was down-regulated by shRNA were more resistant to paclitaxel. However, paclitaxel sensitivity was not affected in bax(-/- MEFs or in human breast cancer cells in which BAX was down-regulated, suggesting that paclitaxel-induced apoptosis is BAK-dependent, but BAX-independent. In human breast cancer cells, paclitaxel treatment resulted in MCL-1 degradation which was prevented by a proteasome inhibitor, MG132. A Cdk inhibitor, roscovitine, blocked paclitaxel-induced MCL-1 degradation and apoptosis, suggesting that Cdk activation at mitotic arrest could induce subsequent MCL-1 degradation in a proteasome-dependent manner. BAK was associated with MCL-1 in untreated cells and became activated in concert with loss of MCL-1 expression and its release from the complex. Our data suggest that BAK is the mediator of paclitaxel-induced apoptosis and could be an alternative target for overcoming paclitaxel resistance.

Xanthium strumarium extract inhibits mammalian cell proliferation through mitotic spindle disruption mediated by xanthatin.

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Sánchez-Lamar, Angel; Piloto-Ferrer, Janet; Fiore, Mario; Stano, Pasquale; Cozzi, Renata; Tofani, Daniela; Cundari, Enrico; Francisco, Marbelis; Romero, Aylema; González, Maria L; Degrassi, Francesca

2016-12-24

Xanthium strumarium L. is a member of the Asteraceae family popularly used with multiple therapeutic purposes. Whole extracts of this plant have shown anti-mitotic activity in vitro suggesting that some components could induce mitotic arrest in proliferating cells. Aim of the present work was to characterize the anti-mitotic properties of the X. strumarium whole extract and to isolate and purify active molecule(s). The capacity of the whole extract to inhibit mitotic progression in mammalian cultured cells was investigated to identify its anti-mitotic activity. Isolation of active component(s) was performed using a bioassay-guided multistep separation procedure in which whole extract was submitted to a progressive process of fractionation and fractions were challenged for their anti-mitotic activity. Our results show for the first time that X. strumarium whole extract inhibits assembly of the mitotic spindle and spindle-pole separation, thereby heavily affecting mitosis, impairing the metaphase to anaphase transition and inducing apoptosis. The purification procedure led to a fraction with an anti-mitotic activity comparable to that of the whole extract. Chemical analysis of this fraction showed that its major component was xanthatin. The present work shows a new activity of X. strumarium extract, i.e. the alteration of the mitotic apparatus in cultured cells that may be responsible for the anti-proliferative activity of the extract. Anti-mitotic activity is shown to be mainly exerted by xanthatin. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

High-dose irradiation induces cell cycle arrest, apoptosis, and developmental defects during Drosophila oogenesis.

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Hee Jin Shim

Full Text Available Ionizing radiation (IR treatment induces a DNA damage response, including cell cycle arrest, DNA repair, and apoptosis in metazoan somatic cells. Because little has been reported in germline cells, we performed a temporal analysis of the DNA damage response utilizing Drosophila oogenesis as a model system. Oogenesis in the adult Drosophila female begins with the generation of 16-cell cyst by four mitotic divisions of a cystoblast derived from the germline stem cells. We found that high-dose irradiation induced S and G2 arrests in these mitotically dividing germline cells in a grp/Chk1- and mnk/Chk2-dependent manner. However, the upstream kinase mei-41, Drosophila ATR ortholog, was required for the S-phase checkpoint but not for the G2 arrest. As in somatic cells, mnk/Chk2 and dp53 were required for the major cell death observed in early oogenesis when oocyte selection and meiotic recombination occurs. Similar to the unscheduled DNA double-strand breaks (DSBs generated from defective repair during meiotic recombination, IR-induced DSBs produced developmental defects affecting the spherical morphology of meiotic chromosomes and dorsal-ventral patterning. Moreover, various morphological abnormalities in the ovary were detected after irradiation. Most of the IR-induced defects observed in oogenesis were reversible and were restored between 24 and 96 h after irradiation. These defects in oogenesis severely reduced daily egg production and the hatch rate of the embryos of irradiated female. In summary, irradiated germline cells induced DSBs, cell cycle arrest, apoptosis, and developmental defects resulting in reduction of egg production and defective embryogenesis.

Radiation-induced mitotic catastrophe in PARG-deficient cells

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Ame, J.Ch.; Fouquerel, E.; Dantzer, F.; De Murcia, G.; Schreiber, V. [IREBS-FRE3211 du CNRS, Universite de Strasbourg, ESBS, Bd Sebastien Brant, BP 10413, 67412 Illkirch Cedex (France); Gauthier, L.R.; Boussin, F.D. [Laboratoire de Radiopathologie/INSERM U967, CEA-DSV-IRCM, 92265 Fontenay aux Roses, Cedex 6 (France); Biard, D. [CEA-DSV-IRCM/INSERM U935, Institut A. Lwoff-CNRS, BP 8, 94801 Villejuif cedex (France)

2009-07-01

Poly(ADP-ribosyl)ation is a post-translational modification of proteins involved in the regulation of chromatin structure, DNA metabolism, cell division and cell death. Through the hydrolysis of poly(ADP-ribose) (PAR), Poly(ADP-ribose) glyco-hydrolase (PARG) has a crucial role in the control of life-and-death balance following DNA insult. Comprehension of PARG function has been hindered by the existence of many PARG isoforms encoded by a single gene and displaying various subcellular localizations. To gain insight into the function of PARG in response to irradiation, we constitutively and stably knocked down expression of PARG isoforms in HeLa cells. PARG depletion leading to PAR accumulation was not deleterious to undamaged cells and was in fact rather beneficial, because it protected cells from spontaneous single-strand breaks and telomeric abnormalities. By contrast, PARG-deficient cells showed increased radiosensitivity, caused by defects in the repair of single- and double-strand breaks and in mitotic spindle checkpoint, leading to alteration of progression of mitosis. Irradiated PARG-deficient cells displayed centrosome amplification leading to mitotic supernumerary spindle poles, and accumulated aberrant mitotic figures, which induced either polyploidy or cell death by mitotic catastrophe. Our results suggest that PARG could be a novel potential therapeutic target for radiotherapy. (authors)

Effect of tumor promoters on ultraviolet light-induced mutation and mitotic recombination in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Kunz, B.A.; Hannan, M.A.; Haynes, R.H.

1980-01-01

Recently, it has been suggested that mitotic recombination is involved in tumor promotion. On this basis, one might expect tumor promoters to be recombinagenic. D7 is a diploid strain of yeast in which both mutation and mitotic recombination can be measured. We have used this strain to assay the known tumor promoters, iodacetate, anthralin, and 12-0-tetradecanoylphorbol-13-acetate, and the cocarcinogen, catechol, for mutagenicity, recombinagenicity, and the ability to enhance ultraviolet light (UV)-induced genetic events. In the absence of preirradiation with UV, iodoacetate was found to be recombinagenic whereas catechol was mutagenic; however, in both cases, the effects were small. Iodoacetate, anthralin, and catechol potentiated UV-induced mitotic crossing-over, aberrant colony formation, and mutation, while catechol also increased UV-induced gene conversion. We were unable to detect any mutagenic or recombinagenic effect of 12-0-tetradecanoyl-phorbol-13-acetate in either whole cells or spheroplasts. Our results do not indicate any consistent correlation between tumor-promoting activity and the ability of an agent to induce mitotic recombination in yeast. However, the ability to potentiate UV-induced mutation and mitotic recombination may reflect the cocarcinogenic activity of certain promoters

Small kinetochore associated protein (SKAP promotes UV-induced cell apoptosis through negatively regulating pre-mRNA processing factor 19 (Prp19.

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Shan Lu

Full Text Available Apoptosis is a regulated cellular suicide program that is critical for the development and maintenance of healthy tissues. Previous studies have shown that small kinetochore associated protein (SKAP cooperates with kinetochore and mitotic spindle proteins to regulate mitosis. However, the role of SKAP in apoptosis has not been investigated. We have identified a new interaction involving SKAP, and we propose a mechanism through which SKAP regulates cell apoptosis. Our experiments demonstrate that both overexpression and knockdown of SKAP sensitize cells to UV-induced apoptosis. Further study has revealed that SKAP interacts with Pre-mRNA processing Factor 19 (Prp19. We find that UV-induced apoptosis can be inhibited by ectopic expression of Prp19, whereas silencing Prp19 has the opposite effect. Additionally, SKAP negatively regulates the protein levels of Prp19, whereas Prp19 does not alter SKAP expression. Finally, rescue experiments demonstrate that the pro-apoptotic role of SKAP is executed through Prp19. Taken together, these findings suggest that SKAP promotes UV-induced cell apoptosis by negatively regulating the anti-apoptotic protein Prp19.

The reduction of radiation-induced mitotic delay by caffeine: a test of the cyclic AMP hypothesis

International Nuclear Information System (INIS)

Oleinick, N.L.; Brewer, E.N.; Rustad, R.C.

1978-01-01

A study has been made of the reduction in γ-radiation-induced mitotic delay by caffeine in the naturally-synchronous plasmodial slime mould. Physarum polycephalum during late G 2 and early prophase, and the results compared with those obtained with other compounds of similar structure and/or physiological function. The reduction of radiation-induced mitotic delay was related to increasing concentrations of caffeine over at least two orders of magnitude. Pre-irradiation treatment with caffeine had no detectable effect. Caffeine had to be present for most, if not all, of the post-irradiation pre-mitotic period. Other chemicals which are reported to inhibit cyclic AMP phosphodiesterase either reduce or increase radiation-induced mitotic delay. The results therefore indicate that the reduction of mitotic delay by caffeine is not a result of altered cyclic AMP levels. (UK)

Radiation induced mitotic delay and stimulation of growth

International Nuclear Information System (INIS)

Feldmann, A.

1974-01-01

The mechanisms responsible for the radiation induced mitotic delay and stimulation of growth are discussed in connection with the results of studies in Lemna minor and Lepidium sativum. The action of temperature seems to be of major importance. As many authors suggest that various chemical agents and slight intoxications also affect mitosis in a way similar to that induced by ionizing radiation, the radiation induced stimulation has lost its specific character and approaches might be found for further investigations of this phenomenon. (MG) [de

Nitric oxide released from JS-K induces cell death by mitotic catastrophe as part of necrosis in glioblastoma multiforme.

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Günzle, Jessica; Osterberg, Nadja; Saavedra, Joseph E; Weyerbrock, Astrid

2016-09-01

The nitric oxide (NO) donor JS-K is specifically activated by glutathione S-transferases (GSTs) in GST-overexpressing cells. We have shown the induction of cell death in glioblastoma multiforme (GBM) cells at high JS-K doses but the mechanism remains unclear. The aim of this study was to determine whether NO-induced cell death is triggered by induction of apoptotic or necrotic pathways. For the first time, we demonstrate that NO induces cell death via mitotic catastrophe (MC) with non-apoptotic mechanisms in GBM cells. Moreover, the level of morphological changes indicating MC correlates with increased necrosis. Therefore, we conclude that MC is the main mechanism by which GBM cells undergo cell death after treatment with JS-K associated with necrosis rather than apoptosis. In addition, we show that PARP1 is not an exclusive marker for late apoptosis but is also involved in MC. Activating an alternative way of cell death can be useful for the multimodal cancer therapy of GBM known for its strong anti-apoptotic mechanisms and drug resistance.

The SUMO protease SENP1 is required for cohesion maintenance and mitotic arrest following spindle poison treatment

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Era, Saho [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Abe, Takuya; Arakawa, Hiroshi [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Kobayashi, Shunsuke [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Szakal, Barnabas [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Yoshikawa, Yusuke; Motegi, Akira; Takeda, Shunichi [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Branzei, Dana, E-mail: dana.branzei@ifom.eu [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy)

2012-09-28

Highlights: Black-Right-Pointing-Pointer SENP1 knockout chicken DT40 cells are hypersensitive to spindle poisons. Black-Right-Pointing-Pointer Spindle poison treatment of SENP1{sup -/-} cells leads to increased mitotic slippage. Black-Right-Pointing-Pointer Mitotic slippage in SENP1{sup -/-} cells associates with apoptosis and endoreplication. Black-Right-Pointing-Pointer SENP1 counteracts sister chromatid separation during mitotic arrest. Black-Right-Pointing-Pointer Plk1-mediated cohesion down-regulation is involved in colcemid cytotoxicity. -- Abstract: SUMO conjugation is a reversible posttranslational modification that regulates protein function. SENP1 is one of the six SUMO-specific proteases present in vertebrate cells and its altered expression is observed in several carcinomas. To characterize SENP1 role in genome integrity, we generated Senp1 knockout chicken DT40 cells. SENP1{sup -/-} cells show normal proliferation, but are sensitive to spindle poisons. This hypersensitivity correlates with increased sister chromatid separation, mitotic slippage, and apoptosis. To test whether the cohesion defect had a causal relationship with the observed mitotic events, we restored the cohesive status of sister chromatids by introducing the TOP2{alpha}{sup +/-} mutation, which leads to increased catenation, or by inhibiting Plk1 and Aurora B kinases that promote cohesin release from chromosomes during prolonged mitotic arrest. Although TOP2{alpha} is SUMOylated during mitosis, the TOP2{alpha}{sup +/-} mutation had no obvious effect. By contrast, inhibition of Plk1 or Aurora B rescued the hypersensitivity of SENP1{sup -/-} cells to colcemid. In conclusion, we identify SENP1 as a novel factor required for mitotic arrest and cohesion maintenance during prolonged mitotic arrest induced by spindle poisons.

Curcumin induces apoptosis-independent death in oesophageal cancer cells.

LENUS (Irish Health Repository)

O'Sullivan-Coyne, G

2012-01-31

BACKGROUND: Oesophageal cancer incidence is increasing and survival rates remain extremely poor. Natural agents with potential for chemoprevention include the phytochemical curcumin (diferuloylmethane). We have examined the effects of curcumin on a panel of oesophageal cancer cell lines. METHODS: MTT (3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assays and propidium iodide staining were used to assess viability and DNA content, respectively. Mitotic catastrophe (MC), apoptosis and autophagy were defined by both morphological criteria and markers such as MPM-2, caspase 3 cleavage and monodansylcadaverine (MDC) staining. Cyclin B and poly-ubiquitinated proteins were assessed by western blotting. RESULTS: Curcumin treatment reduces viability of all cell lines within 24 h of treatment in a 5-50 muM range. Cytotoxicity is associated with accumulation in G2\\/M cell-cycle phases and distinct chromatin morphology, consistent with MC. Caspase-3 activation was detected in two out of four cell lines, but was a minor event. The addition of a caspase inhibitor zVAD had a marginal or no effect on cell viability, indicating predominance of a non-apoptotic form of cell death. In two cell lines, features of both MC and autophagy were apparent. Curcumin-responsive cells were found to accumulate poly-ubiquitinated proteins and cyclin B, consistent with a disturbance of the ubiquitin-proteasome system. This effect on a key cell-cycle checkpoint regulator may be responsible for the mitotic disturbances and consequent cytotoxicity of this drug. CONCLUSION: Curcumin can induce cell death by a mechanism that is not reliant on apoptosis induction, and thus represents a promising anticancer agent for prevention and treatment of oesophageal cancer.

Caspase-Dependent Apoptosis Induced by Telomere Cleavage and TRF2 Loss

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Asha S. Multani

2000-07-01

Full Text Available Chromosomal abnormalities involving telomeric associations (TAs often precede replicative senescence and abnormal chromosome configurations. We report here that telomere cleavage following exposure to proapoptotic agents is an early event in apoptosis. Exposure of human and murine cancer cells to a variety of pro-apoptotic stimuli (staurosporine, thapsigargin, anti-Fas antibody, cancer chemotherapeutic agents resulted in telomere cleavage and aggregation, finally their extrusion from the nuclei. Telomere loss was associated with arrest of cells in G2/M phase and preceded DNA fragmentation. Telomere erosion and subsequent large-scale chromatin cleavage were inhibited by overexpression of the anti -apoptotic protein, bcl-2, two peptide caspase inhibitors (BACMK and zVADfmk, indicating that both events are regulated by caspase activation. The results demonstrate that telomere cleavage is an early chromatin alteration detected in various cancer cell lines leading to drug-induced apoptosis, suggest that this event contributes to mitotic catastrophe and induction of cell death. Results also suggest that the decrease of telomeric-repeat binding factor 2 (TRF2 may be the earliest event in the ara-C-induced telomere shortening, induction of endoreduplication and chromosomal fragmentation leading to cell death.

Arsenic trioxide sensitizes glioblastoma to a myc inhibitor.

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Yayoi Yoshimura

Full Text Available Glioblastoma multiforme (GBM is associated with high mortality due to infiltrative growth and recurrence. Median survival of the patients is less than 15 months, increasing requirements for new therapies. We found that both arsenic trioxide and 10058F4, an inhibitor of Myc, induced differentiation of cancer stem-like cells (CSC of GBM and that arsenic trioxide drastically enhanced the anti-proliferative effect of 10058F4 but not apoptotic effects. EGFR-driven genetically engineered GBM mouse model showed that this cooperative effect is higher in EGFRvIII-expressing INK4a/Arf-/- neural stem cells (NSCs than in control wild type NSCs. In addition, treatment of GBM CSC xenografts with arsenic trioxide and 10058F4 resulted in significant decrease in tumor growth and increased differentiation with concomitant decrease of proneural and mesenchymal GBM CSCs in vivo. Our study was the first to evaluate arsenic trioxide and 10058F4 interaction in GBM CSC differentiation and to assess new opportunities for arsenic trioxide and 10058F4 combination as a promising approach for future differentiation therapy of GBM.

Anaphase-promoting complex/cyclosome protein Cdc27 is a target for curcumin-induced cell cycle arrest and apoptosis

International Nuclear Information System (INIS)

Lee, Seung Joon; Langhans, Sigrid A

2012-01-01

Curcumin (diferuloylmethane), the yellow pigment in the Asian spice turmeric, is a hydrophobic polyphenol from the rhizome of Curcuma longa. Because of its chemopreventive and chemotherapeutic potential with no discernable side effects, it has become one of the major natural agents being developed for cancer therapy. Accumulating evidence suggests that curcumin induces cell death through activation of apoptotic pathways and inhibition of cell growth and proliferation. The mitotic checkpoint, or spindle assembly checkpoint (SAC), is the major cell cycle control mechanism to delay the onset of anaphase during mitosis. One of the key regulators of the SAC is the anaphase promoting complex/cyclosome (APC/C) which ubiquitinates cyclin B and securin and targets them for proteolysis. Because APC/C not only ensures cell cycle arrest upon spindle disruption but also promotes cell death in response to prolonged mitotic arrest, it has become an attractive drug target in cancer therapy. Cell cycle profiles were determined in control and curcumin-treated medulloblastoma and various other cancer cell lines. Pull-down assays were used to confirm curcumin binding. APC/C activity was determined using an in vitro APC activity assay. We identified Cdc27/APC3, a component of the APC/C, as a novel molecular target of curcumin and showed that curcumin binds to and crosslinks Cdc27 to affect APC/C function. We further provide evidence that curcumin preferably induces apoptosis in cells expressing phosphorylated Cdc27 usually found in highly proliferating cells. We report that curcumin directly targets the SAC to induce apoptosis preferably in cells with high levels of phosphorylated Cdc27. Our studies provide a possible molecular mechanism why curcumin induces apoptosis preferentially in cancer cells and suggest that phosphorylation of Cdc27 could be used as a biomarker to predict the therapeutic response of cancer cells to curcumin

Anaphase-promoting complex/cyclosome protein Cdc27 is a target for curcumin-induced cell cycle arrest and apoptosis

Directory of Open Access Journals (Sweden)

Lee Seung Joon

2012-01-01

Full Text Available Abstract Background Curcumin (diferuloylmethane, the yellow pigment in the Asian spice turmeric, is a hydrophobic polyphenol from the rhizome of Curcuma longa. Because of its chemopreventive and chemotherapeutic potential with no discernable side effects, it has become one of the major natural agents being developed for cancer therapy. Accumulating evidence suggests that curcumin induces cell death through activation of apoptotic pathways and inhibition of cell growth and proliferation. The mitotic checkpoint, or spindle assembly checkpoint (SAC, is the major cell cycle control mechanism to delay the onset of anaphase during mitosis. One of the key regulators of the SAC is the anaphase promoting complex/cyclosome (APC/C which ubiquitinates cyclin B and securin and targets them for proteolysis. Because APC/C not only ensures cell cycle arrest upon spindle disruption but also promotes cell death in response to prolonged mitotic arrest, it has become an attractive drug target in cancer therapy. Methods Cell cycle profiles were determined in control and curcumin-treated medulloblastoma and various other cancer cell lines. Pull-down assays were used to confirm curcumin binding. APC/C activity was determined using an in vitro APC activity assay. Results We identified Cdc27/APC3, a component of the APC/C, as a novel molecular target of curcumin and showed that curcumin binds to and crosslinks Cdc27 to affect APC/C function. We further provide evidence that curcumin preferably induces apoptosis in cells expressing phosphorylated Cdc27 usually found in highly proliferating cells. Conclusions We report that curcumin directly targets the SAC to induce apoptosis preferably in cells with high levels of phosphorylated Cdc27. Our studies provide a possible molecular mechanism why curcumin induces apoptosis preferentially in cancer cells and suggest that phosphorylation of Cdc27 could be used as a biomarker to predict the therapeutic response of cancer cells to

Anaphase-promoting complex/cyclosome protein Cdc27 is a target for curcumin-induced cell cycle arrest and apoptosis

Science.gov (United States)

2012-01-01

Background Curcumin (diferuloylmethane), the yellow pigment in the Asian spice turmeric, is a hydrophobic polyphenol from the rhizome of Curcuma longa. Because of its chemopreventive and chemotherapeutic potential with no discernable side effects, it has become one of the major natural agents being developed for cancer therapy. Accumulating evidence suggests that curcumin induces cell death through activation of apoptotic pathways and inhibition of cell growth and proliferation. The mitotic checkpoint, or spindle assembly checkpoint (SAC), is the major cell cycle control mechanism to delay the onset of anaphase during mitosis. One of the key regulators of the SAC is the anaphase promoting complex/cyclosome (APC/C) which ubiquitinates cyclin B and securin and targets them for proteolysis. Because APC/C not only ensures cell cycle arrest upon spindle disruption but also promotes cell death in response to prolonged mitotic arrest, it has become an attractive drug target in cancer therapy. Methods Cell cycle profiles were determined in control and curcumin-treated medulloblastoma and various other cancer cell lines. Pull-down assays were used to confirm curcumin binding. APC/C activity was determined using an in vitro APC activity assay. Results We identified Cdc27/APC3, a component of the APC/C, as a novel molecular target of curcumin and showed that curcumin binds to and crosslinks Cdc27 to affect APC/C function. We further provide evidence that curcumin preferably induces apoptosis in cells expressing phosphorylated Cdc27 usually found in highly proliferating cells. Conclusions We report that curcumin directly targets the SAC to induce apoptosis preferably in cells with high levels of phosphorylated Cdc27. Our studies provide a possible molecular mechanism why curcumin induces apoptosis preferentially in cancer cells and suggest that phosphorylation of Cdc27 could be used as a biomarker to predict the therapeutic response of cancer cells to curcumin. PMID:22280307

Apoptosis-inducing factor (Aif1) mediates anacardic acid-induced apoptosis in Saccharomyces cerevisiae.

Science.gov (United States)

Muzaffar, Suhail; Chattoo, Bharat B

2017-03-01

Anacardic acid is a medicinal phytochemical that inhibits proliferation of fungal as well as several types of cancer cells. It induces apoptotic cell death in various cell types, but very little is known about the mechanism involved in the process. Here, we used budding yeast Saccharomyces cerevisiae as a model to study the involvement of some key elements of apoptosis in the anacardic acid-induced cell death. Plasma membrane constriction, chromatin condensation, DNA degradation, and externalization of phosphatidylserine (PS) indicated that anacardic acid induces apoptotic cell death in S. cerevisiae. However, the exogenous addition of broad-spectrum caspase inhibitor Z-VAD-FMK or deletion of the yeast caspase Yca1 showed that the anacardic acid-induced cell death is caspase independent. Apoptosis-inducing factor (AIF1) deletion mutant was resistant to the anacardic acid-induced cell death, suggesting a key role of Aif1. Overexpression of Aif1 made cells highly susceptible to anacardic acid, further confirming that Aif1 mediates anacardic acid-induced apoptosis. Interestingly, instead of the increase in the intracellular reactive oxygen species (ROS) normally observed during apoptosis, anacardic acid caused a decrease in the intracellular ROS levels. Quantitative real-time PCR analysis showed downregulation of the BIR1 survivin mRNA expression during the anacardic acid-induced apoptosis.

Mitotic recombination induced by chemical and physical agents in the yeast Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Davies, P.J.; Evans, W.E.; Parry, J.M.

1975-01-01

The treatment of diploid cultures of yeast with ultraviolet light (uv), γ-rays, nitrous acid (na) and ethyl methane sulphonate (ems) results in increases in cell death, mitotic gene conversion and crossing-over. Acridine orange (ao) treatment, in contrast, was effective only in increasing the frequency of gene conversion. The individual mutagens were effective in the order uv>na>γ-rays>ao>ems. Prior treatment of yeast cultures in starvation medium produced a significant reduction in the yield of induced gene conversion. The results have been interpreted on the basis of a general model of mitotic gene conversion which involves the post-replication repair of induced lesions involving de novo DNA synthesis without genetic exchange. In contrast mitotic crossing-over appears to involve the action of a repair system independent from excision or post-replication repair which involves genetic exchange between homologous chromosomes

Curcumin induces apoptosis-independent death in oesophageal cancer cells.

LENUS (Irish Health Repository)

O'Sullivan-Coyne, G

2009-10-06

Background:Oesophageal cancer incidence is increasing and survival rates remain extremely poor. Natural agents with potential for chemoprevention include the phytochemical curcumin (diferuloylmethane). We have examined the effects of curcumin on a panel of oesophageal cancer cell lines.Methods:MTT (3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl tetrazolium bromide) assays and propidium iodide staining were used to assess viability and DNA content, respectively. Mitotic catastrophe (MC), apoptosis and autophagy were defined by both morphological criteria and markers such as MPM-2, caspase 3 cleavage and monodansylcadaverine (MDC) staining. Cyclin B and poly-ubiquitinated proteins were assessed by western blotting.Results:Curcumin treatment reduces viability of all cell lines within 24 h of treatment in a 5-50 muM range. Cytotoxicity is associated with accumulation in G2\\/M cell-cycle phases and distinct chromatin morphology, consistent with MC. Caspase-3 activation was detected in two out of four cell lines, but was a minor event. The addition of a caspase inhibitor zVAD had a marginal or no effect on cell viability, indicating predominance of a non-apoptotic form of cell death. In two cell lines, features of both MC and autophagy were apparent. Curcumin-responsive cells were found to accumulate poly-ubiquitinated proteins and cyclin B, consistent with a disturbance of the ubiquitin-proteasome system. This effect on a key cell-cycle checkpoint regulator may be responsible for the mitotic disturbances and consequent cytotoxicity of this drug.Conclusion:Curcumin can induce cell death by a mechanism that is not reliant on apoptosis induction, and thus represents a promising anticancer agent for prevention and treatment of oesophageal cancer.British Journal of Cancer advance online publication, 6 October 2009; doi:10.1038\\/sj.bjc.6605308 www.bjcancer.com.

In vitro and in vivo study of endothelial cells radio-induced death modulation by Sphingosine-1-Phosphate

International Nuclear Information System (INIS)

Bonnaud, St.

2007-01-01

Protecting the vasculature from radiation-induced death is a major concern in tissue radioprotection. Developing a model of endothelial cells radiosensitivity, we proved that HMEC-1 undergo 2 waves of death after exposure to 15 Gy: an early pre mitotic apoptosis dependent of ceramide generation and a delayed DNA damage-induced mitotic death. Sphingosine-1-Phosphate (S1P), a ceramide antagonist, protects HMEC-1 only from early apoptosis, but not from mitotic death. We confirmed in vivo the S1P radioprotection from ceramide-mediated radio-induced apoptosis, and that S1P radioprotection is partially mediated by S1Ps receptors. Segregation between these 2 types of death may give the opportunity to define a new class of radioprotectors for normal tissue where quiescent endothelium represent the most sensitive target, while excluding malignant tumor containing pro-proliferating angiogenic endothelial cells, sensitive to mitotic death. (author)

Mapping genes by meiotic and UV-induced mitotic recombination in Coprinus cinereus

International Nuclear Information System (INIS)

Amirkhanian, J.D.; Cowan, J.W.

1985-01-01

Three morphological mutants in Coprinus cinereus—one spontaneous (den-2) and two chemically induced (zigand sta)—were assigned to linkage groups and utilized in meiotic and mitotic mapping. Mutants den-2 and zig belong to linkage group III, den-2 being close to the centromere and about 20 map units (mu) from zig. The mutant sta in linkage group ‘G’ is at a distance of about 37 mu from ade-3. Mitotic mapping confirmed the gene order in linkage group III and provided evidence that trp-2 in linkage group ‘G’ was between the centromere and ade-3. These morphological mutants are compact in colony growth and therefore suited to high-density plating. The rarity of spontaneously occurring mitotic segregants suggests that diploids of Coprinus cinereus, heterozygous for morphoiogical markers in repuision, could serve as useful test systems for rapid screening of chemical mutagen/carcinogens via mitotic recombination studies

A tumor suppressor role of the Bub3 spindle checkpoint protein after apoptosis inhibition

Science.gov (United States)

Moutinho-Santos, Tatiana

2013-01-01

Most solid tumors contain aneuploid cells, indicating that the mitotic checkpoint is permissive to the proliferation of chromosomally aberrant cells. However, mutated or altered expression of mitotic checkpoint genes accounts for a minor proportion of human tumors. We describe a Drosophila melanogaster tumorigenesis model derived from knocking down spindle assembly checkpoint (SAC) genes and preventing apoptosis in wing imaginal discs. Bub3-deficient tumors that were also deficient in apoptosis displayed neoplastic growth, chromosomal aneuploidy, and high proliferative potential after transplantation into adult flies. Inducing aneuploidy by knocking down CENP-E and preventing apoptosis does not induce tumorigenesis, indicating that aneuploidy is not sufficient for hyperplasia. In this system, the aneuploidy caused by a deficient SAC is not driving tumorigenesis because preventing Bub3 from binding to the kinetochore does not cause hyperproliferation. Our data suggest that Bub3 has a nonkinetochore-dependent function that is consistent with its role as a tumor suppressor. PMID:23609535

Mitotic and apoptotic activity in colorectal neoplasia.

Science.gov (United States)

Kohoutova, Darina; Pejchal, Jaroslav; Bures, Jan

2018-05-18

Colorectal cancer (CRC) is third most commonly diagnosed cancer worldwide. The aim of the prospective study was to evaluate mitosis and apoptosis of epithelial cells at each stage of colorectal neoplasia. A total of 61 persons were enrolled into the study: 18 patients with non-advanced colorectal adenoma (non-a-A), 13 patients with advanced colorectal adenoma (a-A), 13 patients with CRC and 17 controls: individuals with normal findings on colonoscopy. Biopsy samples were taken from pathology (patients) and healthy mucosa (patients and healthy controls). Samples were formalin-fixed paraffin-embedded and stained with haematoxylin-eosin. Mitotic and apoptotic activity were evaluated in lower and upper part of the crypts and in the superficial compartment. Apoptotic activity was also assessed using detection of activated caspase-3. In controls, mitotic activity was present in lower part of crypts, accompanied with low apoptotic activity. Mitotic and apoptotic activity decreased (to almost zero) in upper part of crypts. In superficial compartment, increase in apoptotic activity was observed. Transformation of healthy mucosa into non-a-A was associated with significant increase of mitotic activity in lower and upper part of the crypts and with significant increase of apoptotic activity in all three compartments; p colorectal neoplasia were observed. Detection of activated caspase-3 confirmed the above findings in apoptotic activity. Significant dysregulation of mitosis and apoptosis during the progression of colorectal neoplasia, corresponding with histology, was confirmed. In patients with sporadic colorectal neoplasia, healthy mucosa does not display different mitotic and apoptotic activity compared to mucosa in healthy controls and therefore adequate endoscopic/surgical removal of colorectal neoplasia is sufficient.

Carbamazepine induces mitotic arrest in mammalian Vero cells

International Nuclear Information System (INIS)

Perez Martin, J.M.; Fernandez Freire, P.; Labrador, V.; Hazen, M.J.

2008-01-01

We reported recently that the anticonvulsant drug carbamazepine, at supratherapeutic concentrations, exerts antiproliferative effects in mammalian Vero cells, but the underlying mechanism has not been elucidated. This motivates us to examine rigorously whether growth arrest was associated with structural changes in cellular organization during mitosis. In the present work, we found that exposure of the cells to carbamazepine led to an increase in mitotic index, mainly due to the sustained block at the metaphase/anaphase boundary, with the consequent inhibition of cell proliferation. Indirect immunofluorescence, using antibodies directed against spindle apparatus proteins, revealed that mitotic arrest was associated with formation of monopolar spindles, caused by impairment of centrosome separation. The final consequence of the spindle defects induced by carbamazepine, depended on the duration of cell cycle arrest. Following the time course of accumulation of metaphase and apoptotic cells during carbamazepine treatments, we observed a causative relationship between mitotic arrest and induction of cell death. Conversely, cells released from the block of metaphase by removal of the drug, continued to progress through mitosis and resume normal proliferation. Our results show that carbamazepine shares a common antiproliferative mechanism with spindle-targeted drugs and contribute to a better understanding of the cytostatic activity previously described in Vero cells. Additional studies are in progress to extend these initial findings that define a novel mode of action of carbamazepine in cultured mammalian cells

Carbamazepine induces mitotic arrest in mammalian Vero cells

Energy Technology Data Exchange (ETDEWEB)

Perez Martin, J.M.; Fernandez Freire, P.; Labrador, V. [Departamento de Biologia, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Hazen, M.J. [Departamento de Biologia, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)], E-mail: mariajose.hazen@uam.es

2008-01-01

We reported recently that the anticonvulsant drug carbamazepine, at supratherapeutic concentrations, exerts antiproliferative effects in mammalian Vero cells, but the underlying mechanism has not been elucidated. This motivates us to examine rigorously whether growth arrest was associated with structural changes in cellular organization during mitosis. In the present work, we found that exposure of the cells to carbamazepine led to an increase in mitotic index, mainly due to the sustained block at the metaphase/anaphase boundary, with the consequent inhibition of cell proliferation. Indirect immunofluorescence, using antibodies directed against spindle apparatus proteins, revealed that mitotic arrest was associated with formation of monopolar spindles, caused by impairment of centrosome separation. The final consequence of the spindle defects induced by carbamazepine, depended on the duration of cell cycle arrest. Following the time course of accumulation of metaphase and apoptotic cells during carbamazepine treatments, we observed a causative relationship between mitotic arrest and induction of cell death. Conversely, cells released from the block of metaphase by removal of the drug, continued to progress through mitosis and resume normal proliferation. Our results show that carbamazepine shares a common antiproliferative mechanism with spindle-targeted drugs and contribute to a better understanding of the cytostatic activity previously described in Vero cells. Additional studies are in progress to extend these initial findings that define a novel mode of action of carbamazepine in cultured mammalian cells.

Mineral trioxide aggregate induces osteoblastogenesis via Atf6

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Toyonobu Maeda

2015-06-01

Full Text Available Mineral trioxide aggregate (MTA has been recommended for various uses in endodontics. To understand the effects of MTA on alveolar bone, we examined whether MTA induces osteoblastic differentiation using MC3T3-E1 cells. MTA enhanced mineralization concomitant with alkaline phosphatase activity in a dose- and time-dependent manner. MTA increased production of collagens (Type I and Type III and matrix metalloproteinases (MMP-9 and MMP-13, suggesting that MTA affects bone matrix remodeling. MTA also induced Bglap (osteocalcin but not Bmp2 (bone morphogenetic protein-2 mRNA expression. We observed induction of Atf6 (activating transcription factor 6, an endoplasmic reticulum (ER stress response transcription factor mRNA expression and activation of Atf6 by MTA treatment. Forced expression of p50Atf6 (active form of Atf6 markedly enhanced Bglap mRNA expression. Chromatin immunoprecipitation assay was performed to investigate the increase in p50Atf6 binding to the Bglap promoter region by MTA treatment. Furthermore, knockdown of Atf6 gene expression by introduction of Tet-on Atf6 shRNA expression vector abrogated MTA-induced mineralization. These results suggest that MTA induces in vitro osteoblastogenesis through the Atf6–osteocalcin axis as ER stress signaling. Therefore, MTA in endodontic treatment may affect alveolar bone healing in the resorbed region caused by pulpal infection.

DNA lesions induced by replication stress trigger mitotic aberration and tetraploidy development.

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Yosuke Ichijima

Full Text Available During tumorigenesis, cells acquire immortality in association with the development of genomic instability. However, it is still elusive how genomic instability spontaneously generates during the process of tumorigenesis. Here, we show that precancerous DNA lesions induced by oncogene acceleration, which induce situations identical to the initial stages of cancer development, trigger tetraploidy/aneuploidy generation in association with mitotic aberration. Although oncogene acceleration primarily induces DNA replication stress and the resulting lesions in the S phase, these lesions are carried over into the M phase and cause cytokinesis failure and genomic instability. Unlike directly induced DNA double-strand breaks, DNA replication stress-associated lesions are cryptogenic and pass through cell-cycle checkpoints due to limited and ineffective activation of checkpoint factors. Furthermore, since damaged M-phase cells still progress in mitotic steps, these cells result in chromosomal mis-segregation, cytokinesis failure and the resulting tetraploidy generation. Thus, our results reveal a process of genomic instability generation triggered by precancerous DNA replication stress.

Mitotic Stress Is an Integral Part of the Oncogene-Induced Senescence Program that Promotes Multinucleation and Cell Cycle Arrest

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Dina Dikovskaya

2015-09-01

Full Text Available Oncogene-induced senescence (OIS is a tumor suppression mechanism that blocks cell proliferation in response to oncogenic signaling. OIS is frequently accompanied by multinucleation; however, the origin of this is unknown. Here, we show that multinucleate OIS cells originate mostly from failed mitosis. Prior to senescence, mutant H-RasV12 activation in primary human fibroblasts compromised mitosis, concordant with abnormal expression of mitotic genes functionally linked to the observed mitotic spindle and chromatin defects. Simultaneously, H-RasV12 activation enhanced survival of cells with damaged mitoses, culminating in extended mitotic arrest and aberrant exit from mitosis via mitotic slippage. ERK-dependent transcriptional upregulation of Mcl1 was, at least in part, responsible for enhanced survival and slippage of cells with mitotic defects. Importantly, mitotic slippage and oncogene signaling cooperatively induced senescence and key senescence effectors p21 and p16. In summary, activated Ras coordinately triggers mitotic disruption and enhanced cell survival to promote formation of multinucleate senescent cells.

Regulation of apoptosis-inducing factor-mediated, cisplatin-induced apoptosis by Akt

OpenAIRE

Yang, X; Fraser, M; Abedini, M R; Bai, T; Tsang, B K

2008-01-01

Cisplatin is a first-line chemotherapeutic for ovarian cancer, although chemoresistance limits treatment success. Apoptosis, an important determinant of cisplatin sensitivity, occurs via caspase-dependent and -independent mechanisms. Activation of the protein kinase Akt, commonly observed in ovarian tumours, confers resistance to ovarian cancer cells via inhibition of caspase-dependent apoptosis. However, the effect of Akt on cisplatin-induced, caspase-independent apoptosis remains unclear. W...

Cordyceps militaris Fraction induces apoptosis and G2/M Arrest via c-Jun N-Terminal kinase signaling pathway in oral squamous carcinoma KB Cells.

Science.gov (United States)

Xie, Wangshi; Zhang, Zhang; Song, Liyan; Huang, Chunhua; Guo, Zhongyi; Hu, Xianjing; Bi, Sixue; Yu, Rongmin

2018-01-01

Cordyceps militaris fraction (CMF) has been shown to possess in vitro antitumor activity against human chronic myeloid leukemia K562 cells in our previous research. The in vitro inhibitory activities of CMF on the growth of KB cells were evaluated by viability assay. The apoptotic and cell cycle influences of CMF were detected by 4',6-diamidino-2-phenylindole staining and flow cytometry assay. The expression of different apoptosis-associated proteins and cell cycle regulatory proteins was examined by Western blot assay. The nuclear localization of c-Jun was observed by fluorescence staining. The objective of this study was to investigate the antiproliferative effect of CMF as well as the mechanism underlying the apoptosis and cell cycle arrest it induces in KB cells. CMF suppressed KB cells' proliferation in a dose- and time-dependent manner. Flow cytometric analysis indicated that CMF induced G2/M cell cycle arrest and apoptosis. Western blot analysis revealed that CMF induced caspase-3, caspase-9, and PARP cleavages, and increased the Bax/Bcl-2 ratio. CMF also led to increased expression of p21, decreased expression of cyclin B1, mitotic phosphatase cdc25c, and mitotic kinase cdc2, as well as unchanged expression of p53. In addition, CMF stimulated c-Jun N-terminal kinases (JNK) protein phosphorylations, resulting in upregulated expression of c-Jun and nuclear localization of c-Jun. Pretreatment with JNK inhibitor SP600125 suppressed CMF-induced apoptosis and G2/M arrest. CMF is capable of modulating c-Jun caspase and Bcl-2 family proteins through JNK-dependent apoptosis, which results in G2/M phase arrest in KB cells. CMF could be developed as a promising candidate for the new antitumor agents. CMF exhibited strong anticancer activity against oral squamous carcinoma KB cellsCMF inhibited KB cells' proliferation via induction of apoptosis and G2/M cell cycle arrestCMF activated JNK signaling pathway and promoted the nuclear localization of c-JunCMF regulated the

Hyperthermia-induced apoptosis

NARCIS (Netherlands)

Nijhuis, E.H.A.

2008-01-01

This thesis describes a number of studies that investigated several aspects of heat-induced apoptosis in human lymphoid malignancies. Cells harbour both pro- and anti-apoptotic proteins and the balance between these proteins determines whether a cell is susceptible to undergo apoptosis. In this

Histone phosphorylation during radiation-induced mitotic delay in synchronous plasmodia of Physarum polycephalum

International Nuclear Information System (INIS)

Brewer, E.N.; Oleinick, N.L.

1980-01-01

Using the nearly perfect synchrony of the mitotic stages in Physarum plasmodia, and making use of 32 P as a tracer, studies were made to define the time course of histone phosphorylation during the late G2 and prophase and the alterations in that time course accompanying radiation-induced mitotic delay. Histone H1 was phosphorylated throughout the last 2-3 hours of the mitotic cycle coincident with the early stages of chromosome condensation. H1 phosphorylation appeared to be reduced in irradiated plasmodia. It is postulated that a longer time period, i.e. the mitotic delay, may be required to obtain the same eventual level of H1-phosphate. In normal cultures, nucleosome core histones were phosphorylated late in G2 and prophase, the peak corresponding closely with the γ-transition point. In irradiated plasmodia, phosphorylation of the core histones had an extended time course similar to H1. (U.K.)

Epothilones Suppress Neointimal Thickening in the Rat Carotid Balloon-Injury Model by Inducing Vascular Smooth Muscle Cell Apoptosis through p53-Dependent Signaling Pathway.

Science.gov (United States)

Son, Dong Ju; Jung, Jae Chul; Hong, Jin Tae

2016-01-01

Microtubule stabilizing agents (MTSA) are known to inhibit vascular smooth muscle cell (VSMC) proliferation and migration, and effectively reduce neointimal hyperplasia and restenosis. Epothilones (EPOs), non-taxane MTSA, have been found to be effective in the inhibition of VSMC proliferation and neointimal formation by cell cycle arrest. However, effect of EPOs on apoptosis in hyper-proliferated VSMCs as a possible way to reduce neointimal formation and its action mechanism related to VSMC viability has not been suited yet. Thus, the purposes of the present study was to investigate whether EPOs are able to inhibit neointimal formation by inducing apoptosis within the region of neointimal hyperplasia in balloon-injured rat carotid artery, as well as underlying action mechanism. Treatment of EPO-B and EPO-D significantly induced apoptotic cell death and mitotic catastrophe in hyper-proliferated VSMCs, resulting in cell growth inhibition. Further, EPOs significantly suppressed VSMC proliferation and induced apoptosis by activation of p53-dependent apoptotic signaling pathway, Bax/cytochrome c/caspase-3. We further demonstrated that the local treatment of carotid arteries with EPOs potently inhibited neointimal lesion formation by induction of apoptosis in rat carotid injury model. Our findings demonstrate a potent anti-neointimal hyperplasia property of EPOs by inducing p53-depedent apoptosis in hyper-proliferated VSMCs.

Involvement of CNOT3 in mitotic progression through inhibition of MAD1 expression

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Akinori [Division of Oncology, Department of Cancer Biology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639 (Japan); Kikuguchi, Chisato [Cell Signal Unit, Okinawa Institute of Science and Technology, Kunigami, Okinawa 904-0412 (Japan); Morita, Masahiro; Shimodaira, Tetsuhiro; Tokai-Nishizumi, Noriko; Yokoyama, Kazumasa; Ohsugi, Miho; Suzuki, Toru [Division of Oncology, Department of Cancer Biology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639 (Japan); Yamamoto, Tadashi, E-mail: tyamamot@ims.u-tokyo.ac.jp [Division of Oncology, Department of Cancer Biology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639 (Japan); Cell Signal Unit, Okinawa Institute of Science and Technology, Kunigami, Okinawa 904-0412 (Japan)

2012-03-09

Highlights: Black-Right-Pointing-Pointer CNOT3 depletion increases the mitotic index. Black-Right-Pointing-Pointer CNOT3 inhibits the expression of MAD1. Black-Right-Pointing-Pointer CNOT3 destabilizes the MAD1 mRNA. Black-Right-Pointing-Pointer MAD1 knockdown attenuates the CNOT3 depletion-induced mitotic arrest. -- Abstract: The stability of mRNA influences the dynamics of gene expression. The CCR4-NOT complex, the major deadenylase in mammalian cells, shortens the mRNA poly(A) tail and contributes to the destabilization of mRNAs. The CCR4-NOT complex plays pivotal roles in various physiological functions, including cell proliferation, apoptosis, and metabolism. Here, we show that CNOT3, a subunit of the CCR4-NOT complex, is involved in the regulation of the spindle assembly checkpoint, suggesting that the CCR4-NOT complex also plays a part in the regulation of mitosis. CNOT3 depletion increases the population of mitotic-arrested cells and specifically increases the expression of MAD1 mRNA and its protein product that plays a part in the spindle assembly checkpoint. We showed that CNOT3 depletion stabilizes the MAD1 mRNA, and that MAD1 knockdown attenuates the CNOT3 depletion-induced increase of the mitotic index. Basing on these observations, we propose that CNOT3 is involved in the regulation of the spindle assembly checkpoint through its ability to regulate the stability of MAD1 mRNA.

Involvement of CNOT3 in mitotic progression through inhibition of MAD1 expression

International Nuclear Information System (INIS)

Takahashi, Akinori; Kikuguchi, Chisato; Morita, Masahiro; Shimodaira, Tetsuhiro; Tokai-Nishizumi, Noriko; Yokoyama, Kazumasa; Ohsugi, Miho; Suzuki, Toru; Yamamoto, Tadashi

2012-01-01

Highlights: ► CNOT3 depletion increases the mitotic index. ► CNOT3 inhibits the expression of MAD1. ► CNOT3 destabilizes the MAD1 mRNA. ► MAD1 knockdown attenuates the CNOT3 depletion-induced mitotic arrest. -- Abstract: The stability of mRNA influences the dynamics of gene expression. The CCR4–NOT complex, the major deadenylase in mammalian cells, shortens the mRNA poly(A) tail and contributes to the destabilization of mRNAs. The CCR4–NOT complex plays pivotal roles in various physiological functions, including cell proliferation, apoptosis, and metabolism. Here, we show that CNOT3, a subunit of the CCR4–NOT complex, is involved in the regulation of the spindle assembly checkpoint, suggesting that the CCR4–NOT complex also plays a part in the regulation of mitosis. CNOT3 depletion increases the population of mitotic-arrested cells and specifically increases the expression of MAD1 mRNA and its protein product that plays a part in the spindle assembly checkpoint. We showed that CNOT3 depletion stabilizes the MAD1 mRNA, and that MAD1 knockdown attenuates the CNOT3 depletion-induced increase of the mitotic index. Basing on these observations, we propose that CNOT3 is involved in the regulation of the spindle assembly checkpoint through its ability to regulate the stability of MAD1 mRNA.

The participation of elevated levels of cyclic GMP in the recovery from radiation-induced mitotic delay

International Nuclear Information System (INIS)

Daniel, J.W.; Oleinick, N.L.

1984-01-01

The levels of cyclic AMP and cyclic GMP have been measured in Physarum plasmodia before and after treatment with gamma-radiation, 2 mM caffeine, or combinations of the two agents compared to the length of the radiation-induced mitotic delay. Caffeine alone produces a rapid transient elevation of cyclic AMP and a slower delayed elevation of cyclic GMP. Irradiation elicits an immediate transient increase in cyclic AMP and a later cyclic GMP increase which accompanies or precedes the delayed mitosis. A composite pattern is produced by combinations of radiation and caffeine, a distinctive feature of which is an elevated level of cyclic GMP near the time of the radiation-delayed and caffeine-promoted mitosis. With pretreatment by caffeine, the least radiation-induced mitotic delay occurs when plasmodia are irradiated during the caffeine-elicited increase in cyclic GMP. The plasmodium becomes refractory to the reduction of mitotic delay by caffeine at approximately the time it becomes refractory to the further elevation of cyclic GMP by caffeine. The data support a role for cyclic AMP in the onset of and for cyclic GMP in the recovery from mitotic delay induced by ionizing radiation. (author)

Effect of AC magnetic fields on ultraviolet light-induced mutation and mitotic recombination in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Ager, D.D.; Radul, J.A.

1994-01-01

The ability of 60-Hz magnetic fields to induce genetic damage in Saccharomyces cerevisiae was studied. The frequencies of induced mutation, gene conversion, and reciprocal mitotic crossing over were measured for exposures to 1-millitesla magnetic fields alone or in combination with various preliminary exposures to 254-nm ultraviolet light at intensities of 2-50 J/m 2 . These experiments were performed using a repair-proficient strain as well as a strain incapable of excising ultraviolet-induced thymine dimers. Magnetic field exposures did not induce mutation, gene conversion, or reciprocal mitotic crossing over in either of these strains, nor did the fields influence the frequencies of ultraviolet-induced genetic events. 32 refs., 4 tabs

Hydrogen peroxide induced loss of heterozygosity correlates with replicative lifespan and mitotic asymmetry in Saccharomyces cerevisiae

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Jackson, Erin D.; Parker, Meighan C.; Gupta, Nilin; Rodrigues, Jenny

2016-01-01

Cellular aging in Saccharomyces cerevisiae can lead to genomic instability and impaired mitotic asymmetry. To investigate the role of oxidative stress in cellular aging, we examined the effect of exogenous hydrogen peroxide on genomic instability and mitotic asymmetry in a collection of yeast strains with diverse backgrounds. We treated yeast cells with hydrogen peroxide and monitored the changes of viability and the frequencies of loss of heterozygosity (LOH) in response to hydrogen peroxide doses. The mid-transition points of viability and LOH were quantified using sigmoid mathematical functions. We found that the increase of hydrogen peroxide dependent genomic instability often occurs before a drop in viability. We previously observed that elevation of genomic instability generally lags behind the drop in viability during chronological aging. Hence, onset of genomic instability induced by exogenous hydrogen peroxide treatment is opposite to that induced by endogenous oxidative stress during chronological aging, with regards to the midpoint of viability. This contrast argues that the effect of endogenous oxidative stress on genome integrity is well suppressed up to the dying-off phase during chronological aging. We found that the leadoff of exogenous hydrogen peroxide induced genomic instability to viability significantly correlated with replicative lifespan (RLS), indicating that yeast cells’ ability to counter oxidative stress contributes to their replicative longevity. Surprisingly, this leadoff is positively correlated with an inverse measure of endogenous mitotic asymmetry, indicating a trade-off between mitotic asymmetry and cell’s ability to fend off hydrogen peroxide induced oxidative stress. Overall, our results demonstrate strong associations of oxidative stress to genomic instability and mitotic asymmetry at the population level of budding yeast. PMID:27833823

Arsenic trioxide promotes mitochondrial DNA mutation and cell apoptosis in primary APL cells and NB4 cell line.

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Meng, Ran; Zhou, Jin; Sui, Meng; Li, ZhiYong; Feng, GuoSheng; Yang, BaoFeng

2010-01-01

This study aimed to investigate the effects of arsenic trioxide (As(2)O(3)) on the mitochondrial DNA (mtDNA) of acute promyelocytic leukemia (APL) cells. The NB4 cell line was treated with 2.0 micromol/L As(2)O(3) in vitro, and the primary APL cells were treated with 2.0 micromol/L As(2)O(3) in vitro and 0.16 mg kg(-1) d(-1) As(2)O(3) in vivo. The mitochondrial DNA of all the cells above was amplified by PCR, directly sequenced and analyzed by Sequence Navigatore and Factura software. The apoptosis rates were assayed by flow cytometry. Mitochondrial DNA mutation in the D-loop region was found in NB4 and APL cells before As(2)O(3) use, but the mutation spots were remarkably increased after As(2)O(3) treatment, which was positively correlated to the rates of cellular apoptosis, the correlation coefficient: r (NB4-As2O3)=0.973818, and r (APL-As2O3)=0.934703. The mutation types include transition, transversion, codon insertion or deletion, and the mutation spots in all samples were not constant and regular. It is revealed that As(2)O(3) aggravates mtDNA mutation in the D-loop region of acute promyelocytic leukemia cells both in vitro and in vivo. Mitochondrial DNA might be one of the targets of As(2)O(3) in APL treatment.

Drug-induced premature chromosome condensation (PCC) protocols: cytogenetic approaches in mitotic chromosome and interphase chromatin.

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Gotoh, Eisuke

2015-01-01

Chromosome analysis is a fundamental technique which is used in wide areas of cytogenetic study including karyotyping species, hereditary diseases diagnosis, or chromosome biology study. Chromosomes are usually prepared from mitotic cells arrested by colcemid block protocol. However, obtaining mitotic chromosomes is often hampered under several circumstances. As a result, cytogenetic analysis will be sometimes difficult or even impossible in such cases. Premature chromosome condensation (PCC) (see Note 1) is an alternative method that has proved to be a unique and useful way in chromosome analysis. Former, PCC has been achieved following cell fusion method (cell-fusion PCC) mediated either by fusogenic viruses (e.g., Sendai virus) or cell fusion chemicals (e.g., polyethylene glycol), but the cell fusion PCC has several drawbacks. The novel drug-induced PCC using protein phosphatase inhibitors was introduced about 20 years ago. This method is much simpler and easier even than the conventional mitotic chromosome preparation protocol use with colcemid block and furthermore obtained PCC index (equivalent to mitotic index for metaphase chromosome) is usually much higher than colcemid block method. Moreover, this method allows the interphase chromatin to be condensed to visualize like mitotic chromosomes. Therefore drug-induced PCC has opened the way for chromosome analysis not only in metaphase chromosomes but also in interphase chromatin. The drug-induced PCC has thus proven the usefulness in cytogenetics and other cell biology fields. For this second edition version, updated modifications/changes are supplemented in Subheadings 2, 3, and 4, and a new section describing the application of PCC in chromosome science fields is added with citation of updated references.

Ubiquitin-dependent system controls radiation induced apoptosis

International Nuclear Information System (INIS)

Delic, J.; Magdelenat, H.; Glaisner, S.; Magdelenat, H.; Maciorowski, Z.

1997-01-01

The selective proteolytic pathway, dependent upon 'N-end rule' protein recognition/ubiquitination and on the subsequent proteasome dependent processing of ubiquitin conjugates, operates in apoptosis induced by γ-irradiation. The proteasome inhibitor peptide aldehyde, MG132, efficiently induced apoptosis and was also able (at doses lower than those required for apoptosis induction) to potentiate apoptosis induced by DNA damage. Its specificity is suggested by the induction of the ubiquitin (UbB and UbC) and E1 (ubiquitin activating enzyme) genes and by an altered ubiquitination pattern. More selectively, a di-peptide competitor of the 'N-end rule' of ubiquitin dependent protein processing inhibited radiation induced apoptosis. This inhibition is also followed by an altered ubiquitination pattern and by activation of Poly (ADP-ribose) polymerase (PARP). These data strongly suggest that early apoptosis radiation induced events are controlled by ubiquitin-dependent proteolytic processing. (author)

Vorinostat enhances chemosensitivity to arsenic trioxide in K562 cell line

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Nainong Li

2015-05-01

Full Text Available Objective. This study aimed to investigate the chemosensitive augmentation effect and mechanism of HDAC inhibitor Vorinostat (SAHA in combination with arsenic trioxide (ATO on proliferation and apoptosis of K562 cells.Methods. The CCK-8 assay was used to compare proliferation of the cells. Annexin-V and PI staining by flow cytometry and acridine orange/ethidium bromide stains were used to detect and quantify apoptosis. Western blot was used to detect expression of p21, Akt, pAkt, p210, Acetyl-Histone H3, and Acetyl-Histone H4 proteins.Results. SAHA and ATO inhibited proliferation of K562 cells in an additive and time- and dose-dependent manner. SAHA in combination with ATO showed significant apoptosis of K562 cells in comparison to the single drugs alone (p < 0.01. Both SAHA and ATO alone and in combination showed lower levels of p210 expression. SAHA and SAHA and ATO combined treatment showed increased levels of Acetyl-Histone H3 and Acetyl-Histone H4 protein expression. SAHA alone showed increased expression of p21, while ATO alone and in combination with SAHA showed no significant change. SAHA and ATO combined therapy showed lower levels of Akt and pAkt protein expression than SAHA or ATO alone.Conclusion. SAHA and ATO combined treatment inhibited proliferation, induced apoptosis, and showed a chemosensitive augmentation effect on K562 cells. The mechanism might be associated with increasing histone acetylation levels as well as regulating the Akt signaling pathway.

Dietary flavonoid fisetin induces a forced exit from mitosis by targeting the mitotic spindle checkpoint

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Salmela, Anna-Leena; Pouwels, Jeroen; Varis, Asta; Kukkonen, Anu M.; Toivonen, Pauliina; Halonen, Pasi K.; Perälä, Merja; Kallioniemi, Olli; Gorbsky, Gary J.; Kallio, Marko J.

2009-01-01

Fisetin is a natural flavonol present in edible vegetables, fruits and wine at 2–160 μg/g concentrations and an ingredient in nutritional supplements with much higher concentrations. The compound has been reported to exert anticarcinogenic effects as well as antioxidant and anti-inflammatory activity via its ability to act as an inhibitor of cell proliferation and free radical scavenger, respectively. Our cell-based high-throughput screen for small molecules that override chemically induced mitotic arrest identified fisetin as an antimitotic compound. Fisetin rapidly compromised microtubule drug-induced mitotic block in a proteasome-dependent manner in several human cell lines. Moreover, in unperturbed human cancer cells fisetin caused premature initiation of chromosome segregation and exit from mitosis without normal cytokinesis. To understand the molecular mechanism behind these mitotic errors, we analyzed the consequences of fisetin treatment on the localization and phoshorylation of several mitotic proteins. Aurora B, Bub1, BubR1 and Cenp-F rapidly lost their kinetochore/centromere localization and others became dephosphorylated upon addition of fisetin to the culture medium. Finally, we identified Aurora B kinase as a novel direct target of fisetin. The activity of Aurora B was significantly reduced by fisetin in vitro and in cells, an effect that can explain the observed forced mitotic exit, failure of cytokinesis and decreased cell viability. In conclusion, our data propose that fisetin perturbs spindle checkpoint signaling, which may contribute to the antiproliferative effects of the compound. PMID:19395653

Proteasome inhibition enhances the efficacy of volasertib-induced mitotic arrest in AML in vitro and prolongs survival in vivo.

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Schnerch, Dominik; Schüler, Julia; Follo, Marie; Felthaus, Julia; Wider, Dagmar; Klingner, Kathrin; Greil, Christine; Duyster, Justus; Engelhardt, Monika; Wäsch, Ralph

2017-03-28

Elderly and frail patients, diagnosed with acute myeloid leukemia (AML) and ineligible to undergo intensive treatment, have a dismal prognosis. The small molecule inhibitor volasertib induces a mitotic block via inhibition of polo-like kinase 1 and has shown remarkable anti-leukemic activity when combined with low-dose cytarabine. We have demonstrated that AML cells are highly vulnerable to cell death in mitosis yet manage to escape a mitotic block through mitotic slippage by sustained proteasome-dependent slow degradation of cyclin B. Therefore, we tested whether interfering with mitotic slippage through proteasome inhibition arrests and kills AML cells more efficiently during mitosis. We show that therapeutic doses of bortezomib block the slow degradation of cyclin B during a volasertib-induced mitotic arrest in AML cell lines and patient-derived primary AML cells. In a xenotransplant mouse model of human AML, mice receiving volasertib in combination with bortezomib showed superior disease control compared to mice receiving volasertib alone, highlighting the potential therapeutic impact of this drug combination.

Nuclear interaction of Smac/DIABLO with Survivin at G2/M arrest prompts docetaxel-induced apoptosis in DU145 prostate cancer cells

International Nuclear Information System (INIS)

Kim, Ji Young; Chung, Jin-Yong; Lee, Seung Gee; Kim, Yoon-Jae; Park, Ji-Eun; Yoo, Ki Soo; Yoo, Young Hyun; Park, Young Chul; Kim, Byeong Gee; Kim, Jong-Min

2006-01-01

Smac/DIABLO is released by mitochondria in response to apoptotic stimuli and is thought to antagonize the function of inhibitors of apoptosis proteins. Recently, it has been shown that, like XIAP, Survivin can potentially interact with Smac/DIABLO. However, the precise mechanisms and cellular location of their action have not been determined. We report for the first time that Smac/DIABLO translocates to the nucleus and is colocalized with Survivin at mitotic spindles during apoptosis resulting from G2/M arrest due to docetaxel treatment of DU145 prostate cancer cells. Our data demonstrate that the nuclear interaction of Smac/DIABLO with Survivin is an important step for suppressing the anti-apoptotic function of Survivin in Doc-induced apoptosis. This suggests that the balance between cellular Smac/DIABLO and Survivin levels could be critical for cellular destiny in taxane-treated cancer cells

Aspartame-induced apoptosis in PC12 cells.

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Horio, Yukari; Sun, Yongkun; Liu, Chuang; Saito, Takeshi; Kurasaki, Masaaki

2014-01-01

Aspartame is an artificial sweetner added to many low-calorie foods. The safety of aspartame remains controversial even though there are many studies on its risks. In this study, to understand the physiological effects of trace amounts of artificial sweetners on cells, the effects of aspartame on apoptosis were investigated using a PC12 cell system. In addition, the mechanism of apoptosis induced by aspartame in PC12 cells and effects on apoptotic factors such as cytochrome c, apoptosis-inducing factor, and caspase family proteins were studied by Western blotting and RT-PCR. Aspartame-induced apoptosis in PC12 cells in a dose-dependent manner. In addition, aspartame exposure increased the expressions of caspases 8 and 9, and cytochrome c. These results indicate that aspartame induces apoptosis mainly via mitochondrial pathway involved in apoptosis due to oxigen toxicity. Copyright © 2013 Elsevier B.V. All rights reserved.

Expression of cyclin A in A549 cell line after treatment with arsenic trioxide

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Agnieszka Żuryń

2015-12-01

Full Text Available Background: Arsenic trioxide (ATO is an effective drug used in acute promyelocytic leukemia (AML. Many reports suggest that ATO can also be applied as an anticancer agent for solid tumors in the future. The influence of arsenic trioxide on the expression of different cell cycle regulators is poorly recognized. The purpose of the current study is to investigate how arsenic trioxide affects cyclin A expression and localization in the A549 cell line.Materials and methods: Morphological and ultrastructural changes in A549 cells were observed using light and transmission electron microscopes. Cyclin A localization was determined by immunofluorescence. Image-based cytometry was applied to evaluate the effect of arsenic trioxide on apoptosis and the cell cycle. Expression of cyclin A mRNA was quantified by real-time PCR.Results: After treatment with arsenic trioxide, increased numbers of cells with cytoplasmic localization of cyclin A were observed. The doses of 10 and 15 μM ATO slightly reduced expression of cyclin A mRNA. The apoptotic phenotype of cells was poorly represented, and the Tali imagebased cytometry analysis showed low percentages of apoptotic cells. The A549 population displayed an enriched fraction of cells in G0/G1 phase in the presence of 5μM ATO, whereas starting from the higher concentrations of the drug, i.e. 10 and 15 μM ATO, the G2/M fraction was on the increase.Discussion: Low expression of cyclin A in the A549 cell line may constitute a potential factor determining arsenic trioxide resistance. It could be hypothesized that the observed alterations in cyclin A expression/distribution may correlate well with changes in cell cycle regulation in our model, which in turn determines the outcome of the treatment.

Effect of 60-Hz magnetic fields on ultraviolet light-induced mutation and mitotic recombination in Saccharomyces cerevisiae.

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Ager, D D; Radul, J A

1992-12-01

The purpose of this study was to examine the effect of extremely low frequency (ELF) magnetic fields on the induction of genetic damage. In general, mutational studies involving ELF magnetic fields have proven negative. However, studies examining sister-chromatid exchange and chromosome aberrations have yielded conflicting results. In this study, we have examined whether 60-Hz magnetic fields are capable of inducing mutation or mitotic recombination in the yeast Saccharomyces cerevisiae. In addition we determined whether magnetic fields were capable of altering the genetic response of S. cerevisiae to UV (254 nm). We measured the frequencies of induced mutation, gene conversion and reciprocal mitotic crossing-over for exposures to magnetic fields alone (1 mT) or in combination with various UV exposures (2-50 J/m2). These experiments were performed using a repair-proficient strain (RAD+), as well as a strain of yeast (rad3) which is incapable of excising UV-induced thymine dimers. Magnetic field exposures did not induce mutation, gene conversion or reciprocal mitotic crossing-over in either of these strains, nor did the fields influence the frequencies of UV-induced genetic events.

Molecular mechanism of apoptosis and characterization of apoptosis induced by radiation

International Nuclear Information System (INIS)

Li Yumin; Zhang Yuguang; Li Yukun

1999-01-01

The major discoveries of apoptosis research in recent years were reviewed briefly. The mechanisms of caspases/ICE gene family and bcl-2 gene family on apoptosis were analyzed. And the signal transduction pathway of apoptosis found currently has been summarized. The characterizations of apoptosis induced by radiation such as time-effects, dose-effects and the radiosensibility were summed up

6-Nitro-2-(3-hydroxypropyl-1H-benz[de]isoquinoline-1,3-dione, a potent antitumor agent, induces cell cycle arrest and apoptosis

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Singh Shashank K

2010-12-01

Full Text Available Abstract Background Anticancer activities of several substituted naphthalimides (1H-benz[de]isoquinoline-1,3-diones are well documented. Some of them have undergone Phase I-II clinical trials. Presently a series of ten N-(hydroxyalkyl naphthalimides (compounds 1a-j were evaluated as antitumor agents. Methods Compounds 1a-j were initially screened in MOLT-4, HL-60 and U-937 human tumor cell lines and results were compared with established clinical drugs. Cytotoxicities of compounds 1d and 1i were further evaluated in a battery of human tumor cell lines and in normal human peripheral blood mononuclear cells. Cell cycle analysis of compound 1i treated MOLT-4 cells was studied by flow cytometry. Its apoptosis inducing effect was carried out in MOLT-4 and HL-60 cells by flow cytometry using annexin V-FITC/PI double staining method. The activities of caspase-3 and caspase-6 in MOLT-4 cells following incubation with compound 1i were measured at different time intervals. Morphology of the MOLT-4 cells after treatment with 1i was examined under light microscope and transmission electron microscope. 3H-Thymidine and 3H-uridine incorporation in S-180 cells in vitro following treatment with 8 μM concentration of compounds 1d and 1i were studied. Results 6-Nitro-2-(3-hydroxypropyl-1H-benz[de]isoquinoline-1,3-dione (compound 1i, has exhibited maximum activity as it induced significant cytotoxicity in 8 out of 13 cell lines employed. Interestingly it did not show any cytotoxicity against human PBMC (IC50 value 273 μM. Cell cycle analysis of compound 1i treated MOLT-4 cells demonstrated rise in sub-G1 fraction and concomitant accumulation of cells in S and G2/M phases, indicating up-regulation of apoptosis along with mitotic arrest and/or delay in exit of daughter cells from mitotic cycle respectively. Its apoptosis inducing effect was confirmed in flow cytometric study in MOLT-4 and the action was mediated by activation of both caspase 3 and 6. Light and

Mitochondrial dysfunction in lyssavirus-induced apoptosis.

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Gholami, Alireza; Kassis, Raïd; Real, Eléonore; Delmas, Olivier; Guadagnini, Stéphanie; Larrous, Florence; Obach, Dorothée; Prevost, Marie-Christine; Jacob, Yves; Bourhy, Hervé

2008-05-01

Lyssaviruses are highly neurotropic viruses associated with neuronal apoptosis. Previous observations have indicated that the matrix proteins (M) of some lyssaviruses induce strong neuronal apoptosis. However, the molecular mechanism(s) involved in this phenomenon is still unknown. We show that for Mokola virus (MOK), a lyssavirus of low pathogenicity, the M (M-MOK) targets mitochondria, disrupts the mitochondrial morphology, and induces apoptosis. Our analysis of truncated M-MOK mutants suggests that the information required for efficient mitochondrial targeting and dysfunction, as well as caspase-9 activation and apoptosis, is held between residues 46 and 110 of M-MOK. We used a yeast two-hybrid approach, a coimmunoprecipitation assay, and confocal microscopy to demonstrate that M-MOK physically associates with the subunit I of the cytochrome c (cyt-c) oxidase (CcO) of the mitochondrial respiratory chain; this is in contrast to the M of the highly pathogenic Thailand lyssavirus (M-THA). M-MOK expression induces a significant decrease in CcO activity, which is not the case with M-THA. M-MOK mutations (K77R and N81E) resulting in a similar sequence to M-THA at positions 77 and 81 annul cyt-c release and apoptosis and restore CcO activity. As expected, the reverse mutations, R77K and E81N, introduced in M-THA induce a phenotype similar to that due to M-MOK. These features indicate a novel mechanism for energy depletion during lyssavirus-induced apoptosis.

In vitro and in vivo study of endothelial cells radio-induced death modulation by Sphingosine-1-Phosphate; Etude in vitro et in vivo de la regulation de la mort radioinduite des cellules endotheliales par la Sphingosine-1-Phosphate

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Bonnaud, St

2007-01-15

Protecting the vasculature from radiation-induced death is a major concern in tissue radioprotection. Developing a model of endothelial cells radiosensitivity, we proved that HMEC-1 undergo 2 waves of death after exposure to 15 Gy: an early pre mitotic apoptosis dependent of ceramide generation and a delayed DNA damage-induced mitotic death. Sphingosine-1-Phosphate (S1P), a ceramide antagonist, protects HMEC-1 only from early apoptosis, but not from mitotic death. We confirmed in vivo the S1P radioprotection from ceramide-mediated radio-induced apoptosis, and that S1P radioprotection is partially mediated by S1Ps receptors. Segregation between these 2 types of death may give the opportunity to define a new class of radioprotectors for normal tissue where quiescent endothelium represent the most sensitive target, while excluding malignant tumor containing pro-proliferating angiogenic endothelial cells, sensitive to mitotic death. (author)

Chk2 mediates RITA-induced apoptosis.

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de Lange, J; Verlaan-de Vries, M; Teunisse, A F A S; Jochemsen, A G

2012-06-01

Reactivation of the p53 tumor-suppressor protein by small molecules like Nutlin-3 and RITA (reactivation of p53 and induction of tumor cell apoptosis) is a promising strategy for cancer therapy. The molecular mechanisms involved in the responses to RITA remain enigmatic. Several groups reported the induction of a p53-dependent DNA damage response. Furthermore, the existence of a p53-dependent S-phase checkpoint has been suggested, involving the checkpoint kinase Chk1. We have recently shown synergistic induction of apoptosis by RITA in combination with Nutlin-3, and we observed concomitant Chk2 phosphorylation. Therefore, we investigated whether Chk2 contributes to the cellular responses to RITA. Strikingly, the induction of apoptosis seemed entirely Chk2 dependent. Transcriptional activity of p53 in response to RITA required the presence of Chk2. A partial rescue of apoptosis observed in Noxa knockdown cells emphasized the relevance of p53 transcriptional activity for RITA-induced apoptosis. In addition, we observed an early p53- and Chk2-dependent block of DNA replication upon RITA treatment. Replicating cells seemed more prone to entering RITA-induced apoptosis. Furthermore, the RITA-induced DNA damage response, which was not a secondary effect of apoptosis induction, was strongly attenuated in cells lacking p53 or Chk2. In conclusion, we identified Chk2 as an essential mediator of the cellular responses to RITA.

Experimental study on effect of arsenic trioxide on vascular smooth muscle cells

International Nuclear Information System (INIS)

Lu Qin; An Yanli; Niu Huanzhang; Teng Gaojun; Wang Zihao; Zhang Dongsheng; Fang Juanjuan

2007-01-01

Objective: To investigate the effect of arsenic trioxide (As 2 O 3 ) nanoparticles on rabbit vascular smooth muscle cells in vitro in comparison with normal form As 2 O 3 . Methods: The rabbit vascular smooth muscle cells were cultured in vitro. Nano and normal forms of As 2 O 3 with drug concentrations of 3 μmol/L were added into the cells. Cell proliferation curve was drawn according to the light absorption values of MTT test. Flow cytometry was applied to observe the apoptosis. DNA was extracted and underwent electrophoresis. Results: Cell proliferation treated with the 3 μmol/L concentration of As 2 O 3 was inhibited. Cell growth was inhibited markedly with increased treatment time, and the inhibition effect of nano drug form seemed stronger than that of normal form. MTT light absorption values of cells treated at 24, 48 and 72 h showed statistically significant difference (H=10.934, 15.039, 15.539, P 2 O 3 , normal drug form of As 2 O 3 and control group of cells without As 2 O 3 were 44.97%, 58.54%, 74.02% respectively. The early apoptosis rates were 16.89%, 11.27%, 11.20%, late apoptosis rates were 26.56%, 23.60%, 12.46%, and necrosis rates were 11.58%, 6.59%, 2.32% respectively. Agarose gel electrophoresis showed 'ladder' strand of DNA, with more strands and obscurity for nano drug form treated cells. Conclusion: Arsenic trioxide may inhibit the growth of rabbit vascular smooth muscle cells. The nano drug form showed stronger inhibition effect than that of the normal drug form. (authors)

Csk regulates angiotensin II-induced podocyte apoptosis.

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Zhang, Lu; Ren, Zhilong; Yang, Qian; Ding, Guohua

2016-07-01

Increasing data have shown that angiotensin II (Ang II) perpetuates podocyte injury and promotes progression to end-stage kidney disease. The mechanism underlying Ang II-induced podocyte apoptosis has not been established. C-terminal Src kinase (Csk) is a cytoplasmic kinase that interacts with scaffolding proteins involved in cell growth, adhesion, and polarization, and the role of Csk in regulating cellular apoptosis has gradually attracted attention. This study evaluates the role of Csk in Ang II-induced podocyte apoptosis. In vivo, Wistar rats were randomly subjected to a normal saline or Ang II infusion. In vitro, we exposed differentiated mouse podocytes to Ang II. Ang II increased Csk expression and induced podocyte apoptosis, stimulated Csk translocation and binding to Caveolin-1, and stimulated decreased Fyn pY416, increased Fyn pY529, and nephrin dephosphorylation. Csk knockdown prevented Ang II-induced podocyte apoptosis, reduced Fyn kinase inactivation, and increased the interaction between nephrin and the activated form of Fyn, accompanied by a reduced interaction between Csk and Caveolin-1. These findings indicate that Ang II induces podocyte injury via a Csk-dependent pathway.

Research Advances on Pathways of Nickel-Induced Apoptosis

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Guo, Hongrui; Chen, Lian; Cui, Hengmin; Peng, Xi; Fang, Jing; Zuo, Zhicai; Deng, Junliang; Wang, Xun; Wu, Bangyuan

2015-01-01

High concentrations of nickel (Ni) are harmful to humans and animals. Ni targets a number of organs and produces multiple toxic effects. Apoptosis is important in Ni-induced toxicity of the kidneys, liver, nerves, and immune system. Apoptotic pathways mediated by reactive oxygen species (ROS), mitochondria, endoplasmic reticulum (ER), Fas, and c-Myc participate in Ni-induced cell apoptosis. However, the exact mechanism of apoptosis caused by Ni is still unclear. Understanding the mechanism of Ni-induced apoptosis may help in designing measures to prevent Ni toxicity. PMID:26703593

Frequencies of mutagen-induced coincident mitotic recombination at unlinked loci in Saccharomyces cerevisiae

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Freeman, Kathryn M. [Department of Biology, College of the Holy Cross, One College Street, Worcester, MA 01610-2395 (United States); Hoffmann, George R. [Department of Biology, College of the Holy Cross, One College Street, Worcester, MA 01610-2395 (United States)]. E-mail: ghoffmann@holycross.edu

2007-03-01

Frequencies of coincident genetic events were measured in strain D7 of Saccharomyces cerevisiae. This diploid strain permits the detection of mitotic gene conversion involving the trp5-12 and trp5-27 alleles, mitotic crossing-over and gene conversion leading to the expression of the ade2-40 and ade2-119 alleles as red and pink colonies, and reversion of the ilv1-92 allele. The three genes are on different chromosomes, and one might expect that coincident (simultaneous) genetic alterations at two loci would occur at frequencies predicted by those of the single alterations acting as independent events. Contrary to this expectation, we observed that ade2 recombinants induced by bleomycin, {beta}-propiolactone, and ultraviolet radiation occur more frequently among trp5 convertants than among total colonies. This excess among trp5 recombinants indicates that double recombinants are more common than expected for independent events. No similar enrichment was found among Ilv{sup +} revertants. The possibility of an artifact in which haploid yeasts that mimic mitotic recombinants are generated by a low frequency of cryptic meiosis has been excluded. Several hypotheses that can explain the elevated incidence of coincident mitotic recombination have been evaluated, but the cause remains uncertain. Most evidence suggests that the excess is ascribable to a subset of the population being in a recombination-prone state.

Frequencies of mutagen-induced coincident mitotic recombination at unlinked loci in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Freeman, Kathryn M.; Hoffmann, George R.

2007-01-01

Frequencies of coincident genetic events were measured in strain D7 of Saccharomyces cerevisiae. This diploid strain permits the detection of mitotic gene conversion involving the trp5-12 and trp5-27 alleles, mitotic crossing-over and gene conversion leading to the expression of the ade2-40 and ade2-119 alleles as red and pink colonies, and reversion of the ilv1-92 allele. The three genes are on different chromosomes, and one might expect that coincident (simultaneous) genetic alterations at two loci would occur at frequencies predicted by those of the single alterations acting as independent events. Contrary to this expectation, we observed that ade2 recombinants induced by bleomycin, β-propiolactone, and ultraviolet radiation occur more frequently among trp5 convertants than among total colonies. This excess among trp5 recombinants indicates that double recombinants are more common than expected for independent events. No similar enrichment was found among Ilv + revertants. The possibility of an artifact in which haploid yeasts that mimic mitotic recombinants are generated by a low frequency of cryptic meiosis has been excluded. Several hypotheses that can explain the elevated incidence of coincident mitotic recombination have been evaluated, but the cause remains uncertain. Most evidence suggests that the excess is ascribable to a subset of the population being in a recombination-prone state

DNA Strand Breaks in Mitotic Germ Cells of Caenorhabditis elegans Evaluated by Comet Assay

Science.gov (United States)

Park, Sojin; Choi, Seoyun; Ahn, Byungchan

2016-01-01

DNA damage responses are important for the maintenance of genome stability and the survival of organisms. Such responses are activated in the presence of DNA damage and lead to cell cycle arrest, apoptosis, and DNA repair. In Caenorhabditis elegans, double-strand breaks induced by DNA damaging agents have been detected indirectly by antibodies against DSB recognizing proteins. In this study we used a comet assay to detect DNA strand breaks and to measure the elimination of DNA strand breaks in mitotic germline nuclei of C. elegans. We found that C. elegans brc-1 mutants were more sensitive to ionizing radiation and camptothecin than the N2 wild-type strain and repaired DNA strand breaks less efficiently than N2. This study is the first demonstration of direct measurement of DNA strand breaks in mitotic germline nuclei of C. elegans. This newly developed assay can be applied to detect DNA strand breaks in different C. elegans mutants that are sensitive to DNA damaging agents. PMID:26903030

The moyamoya disease susceptibility variant RNF213 R4810K (rs112735431) induces genomic instability by mitotic abnormality

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Hitomi, Toshiaki [Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Habu, Toshiyuki [Radiation Biology Center, Kyoto University, Kyoto (Japan); Kobayashi, Hatasu; Okuda, Hiroko; Harada, Kouji H. [Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Osafune, Kenji [Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto (Japan); Taura, Daisuke; Sone, Masakatsu [Department of Medicine and Clinical Science, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Asaka, Isao; Ameku, Tomonaga; Watanabe, Akira; Kasahara, Tomoko; Sudo, Tomomi; Shiota, Fumihiko [Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto (Japan); Hashikata, Hirokuni; Takagi, Yasushi [Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Morito, Daisuke [Faculty of Life Sciences, Kyoto Sangyo University, Kyoto (Japan); Miyamoto, Susumu [Department of Neurosurgery, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Nakao, Kazuwa [Department of Medicine and Clinical Science, Graduate School of Medicine, Kyoto University, Kyoto (Japan); Koizumi, Akio, E-mail: koizumi.akio.5v@kyoto-u.ac.jp [Department of Health and Environmental Sciences, Graduate School of Medicine, Kyoto University, Kyoto (Japan)

2013-10-04

Highlights: •Overexpression of RNF213 R4810K inhibited cell proliferation. •Overexpression of RNF213 R4810K had the time of mitosis 4-fold and mitotic failure. •R4810K formed a complex with MAD2 more readily than wild-type. •iPSECs from the MMD patients had elevated mitotic failure compared from the control. •RNF213 R4810K induced mitotic abnormality and increased risk of aneuploidy. -- Abstract: Moyamoya disease (MMD) is a cerebrovascular disease characterized by occlusive lesions in the Circle of Willis. The RNF213 R4810K polymorphism increases susceptibility to MMD. In the present study, we characterized phenotypes caused by overexpression of RNF213 wild type and R4810K variant in the cell cycle to investigate the mechanism of proliferation inhibition. Overexpression of RNF213 R4810K in HeLa cells inhibited cell proliferation and extended the time of mitosis 4-fold. Ablation of spindle checkpoint by depletion of mitotic arrest deficiency 2 (MAD2) did not shorten the time of mitosis. Mitotic morphology in HeLa cells revealed that MAD2 colocalized with RNF213 R4810K. Immunoprecipitation revealed an RNF213/MAD2 complex: R4810K formed a complex with MAD2 more readily than RNF213 wild-type. Desynchronized localization of MAD2 was observed more frequently during mitosis in fibroblasts from patients (n = 3, 61.0 ± 8.2%) compared with wild-type subjects (n = 6, 13.1 ± 7.7%; p < 0.01). Aneuploidy was observed more frequently in fibroblasts (p < 0.01) and induced pluripotent stem cells (iPSCs) (p < 0.03) from patients than from wild-type subjects. Vascular endothelial cells differentiated from iPSCs (iPSECs) of patients and an unaffected carrier had a longer time from prometaphase to metaphase than those from controls (p < 0.05). iPSECs from the patients and unaffected carrier had significantly increased mitotic failure rates compared with controls (p < 0.05). Thus, RNF213 R4810K induced mitotic abnormalities and increased risk of genomic instability.

The moyamoya disease susceptibility variant RNF213 R4810K (rs112735431) induces genomic instability by mitotic abnormality

International Nuclear Information System (INIS)

Hitomi, Toshiaki; Habu, Toshiyuki; Kobayashi, Hatasu; Okuda, Hiroko; Harada, Kouji H.; Osafune, Kenji; Taura, Daisuke; Sone, Masakatsu; Asaka, Isao; Ameku, Tomonaga; Watanabe, Akira; Kasahara, Tomoko; Sudo, Tomomi; Shiota, Fumihiko; Hashikata, Hirokuni; Takagi, Yasushi; Morito, Daisuke; Miyamoto, Susumu; Nakao, Kazuwa; Koizumi, Akio

2013-01-01

Highlights: •Overexpression of RNF213 R4810K inhibited cell proliferation. •Overexpression of RNF213 R4810K had the time of mitosis 4-fold and mitotic failure. •R4810K formed a complex with MAD2 more readily than wild-type. •iPSECs from the MMD patients had elevated mitotic failure compared from the control. •RNF213 R4810K induced mitotic abnormality and increased risk of aneuploidy. -- Abstract: Moyamoya disease (MMD) is a cerebrovascular disease characterized by occlusive lesions in the Circle of Willis. The RNF213 R4810K polymorphism increases susceptibility to MMD. In the present study, we characterized phenotypes caused by overexpression of RNF213 wild type and R4810K variant in the cell cycle to investigate the mechanism of proliferation inhibition. Overexpression of RNF213 R4810K in HeLa cells inhibited cell proliferation and extended the time of mitosis 4-fold. Ablation of spindle checkpoint by depletion of mitotic arrest deficiency 2 (MAD2) did not shorten the time of mitosis. Mitotic morphology in HeLa cells revealed that MAD2 colocalized with RNF213 R4810K. Immunoprecipitation revealed an RNF213/MAD2 complex: R4810K formed a complex with MAD2 more readily than RNF213 wild-type. Desynchronized localization of MAD2 was observed more frequently during mitosis in fibroblasts from patients (n = 3, 61.0 ± 8.2%) compared with wild-type subjects (n = 6, 13.1 ± 7.7%; p < 0.01). Aneuploidy was observed more frequently in fibroblasts (p < 0.01) and induced pluripotent stem cells (iPSCs) (p < 0.03) from patients than from wild-type subjects. Vascular endothelial cells differentiated from iPSCs (iPSECs) of patients and an unaffected carrier had a longer time from prometaphase to metaphase than those from controls (p < 0.05). iPSECs from the patients and unaffected carrier had significantly increased mitotic failure rates compared with controls (p < 0.05). Thus, RNF213 R4810K induced mitotic abnormalities and increased risk of genomic instability

Characterization of radiation-induced Apoptosis in rodent cell lines

International Nuclear Information System (INIS)

Guo, Min; Chen, Changhu; Ling, C.C.

1997-01-01

For REC:myc(ch1), Rat1 and Rat1:myc b cells, we determined the events in the development of radiation-induced apoptosis to be in the following order: cell division followed by chromatin condensation, membrane blebbing, loss of adhesion and the uptake of vital dye. Experimental data which were obtained using 4 He ions of well defined energies and which compared the dependence of apoptosis and clonogenic survival on 4 He range strongly suggested that in our cells both apoptosis and loss of clonogenic survival resulted from radiation damage to the cell nucleus. Corroboratory evidence was that BrdU incorporation sensitized these cells to radiation-induced apoptosis. Comparing the dose response for apoptosis and the clonogenic survival curves for Rat1 and Rat1:myc b cells, we concluded that radiation-induced cell inactivation as assayed by clonogenic survival, and that a modified linear-quadratic model, proposed previously, modeled such a contribution effectively. In the same context, the selective increase in radiation-induced apoptosis. Comparing the dose response for apoptosis and the clonogenic survival curves for Rat1 and Rat1:myc b cells, we concluded that radiation-induced apoptosis contributed to the overall radiation-induced cell inactivation as assayed by clonogenic survival, and that a modified linear-quadratic model, proposed previously, modeled such a contribution effectively. In the same context, the selective increase in radiation-induced apoptosis during late S and G 2 phases reduced the relative radioresistance observed for clonogenic survival during late S and G 2 phases. 30 refs., 8 figs

Effect of pH on radiation-induced apoptosis

International Nuclear Information System (INIS)

Chang, W. Song; Park, Heon J.; Lyons, John C.; Auger, Elizabeth A.; Lee, Hyung-Sik

1996-01-01

Purpose/Objective: The effect of environmental pH on the radiation-induced apoptosis in tumor cells in vitro was investigated. Materials and Methods: SCK mammary adenocarcinoma cells of A/J mice were irradiated with γ-rays using a 137 Cs irradiator and incubated in media of different pHs. After incubation at 37 degree sign C for 24-120 hrs., the extent of apoptosis was determined using agarose gel electrophoresis of DNA, in situ TUNEL staining, flow cytometry, and release of 3 H from 3 H-thymidine labeled cells. The membrane integrity, using the trypan blue exclusion method, and the clonogenicity of the cells were also determined. Results: Irradiation with 2-12 Gy of γ-rays induced apoptosis in pH 7.5 medium within 48 hrs. The radiation-induced apoptosis progressively declined as the medium pH was lowered so that little apoptosis occurred in 48 hrs. after irradiation with 12 Gy in pH 6.6 medium. However, when the cells were irradiated and incubated for 48 hrs. in pH 6.6 medium and then medium was replaced with pH 7.5 medium, apoptosis promptly occurred. Apoptosis also occurred even in pH 6.6 medium when the cells were irradiated and maintained in pH 7.5 medium for 8 hrs. or longer post-irradiation before incubation in pH 6.6 medium. Conclusion: An acidic environment markedly suppresses radiation-induced apoptosis probably by suppressing the expression of initial signals responsible for irradiation-induced apoptosis. Indications are that the signals persist in an acidic environment and trigger apoptosis when the environmental acidity is eased. Our results suggest that the acidic environment in human tumors may inhibit the apoptosis after irradiation. However, apoptosis may be triggered when reoxygenation occurs after irradiation, and thus, the intratumor environment becomes less acidic after irradiation. Not only the change in pO 2 but the change in pH during the course of fractionated radiotherapy may greatly influence the outcome of the treatment

Single-wall carbon nanohorns (SWNHs) inhibited proliferation of human glioma cells and promoted its apoptosis

Energy Technology Data Exchange (ETDEWEB)

Li, Yunjun [The Military General Hospital of Beijing PLA, Affiliated Bayi Brain Hospital (China); Zhang, Jinqian, E-mail: jingwanghou@yahoo.com.cn [Capital Medical University, Institute of Infectious Diseases, Beijing Ditan Hospital (China); Zhao, Ming [Peking University, Department of Chemical Biology, School of Pharmaceutical Sciences (China); Shi, Zujin [Peking University, Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering (China); Chen, Xin; He, Xihui; Han, Nanyin, E-mail: jingwanghou@sina.com [Peking University, Department of Chemical Biology, School of Pharmaceutical Sciences (China); Xu, Ruxiang, E-mail: everbright999@163.com [The Military General Hospital of Beijing PLA, Affiliated Bayi Brain Hospital (China)

2013-08-15

Although single-wall carbon nanohorns (SWNHs) have been demonstrated to accumulate to cytotoxic levels within organs of various animal models and cell types, they have been exploited for cancer therapies. The role of SWNHs in human glioma cell lines was unclear. To address this question, the research about direct role of SWNHs on the growth, proliferation, and apoptosis of human glioma cell lines (U87, U251, and U373) had been performed. Our results indicate that particle size of SWNHs in water is between 342 and 712 nm, the films of SEM show that SWNHs on PS surface are individual particles. SWNHs significantly delayed mitotic entry of human glioma cell lines cells, and inhibited its proliferation in a time- and dose-dependent manner. SWNHs induced a significant increase in G1 phase and inhibition of S phase followed the gradually increasing concentrations. SWNHs in human glioma cell lines cells significantly induced apoptosis followed by their gradually increasing concentrations. The TEM images showed that individual spherical SWNHs particles smaller than 100 nm in diameters were localized inside lysosomes of human glioma cell lines. SWNHs inhibited mitotic entry, growth, and proliferation of human glioma cell lines, and promoted its apoptosis. SWNHs may be a novel opportunity or method for the research on treatment of human glioma.

Single-wall carbon nanohorns (SWNHs) inhibited proliferation of human glioma cells and promoted its apoptosis

Science.gov (United States)

Li, Yunjun; Zhang, Jinqian; Zhao, Ming; Shi, Zujin; Chen, Xin; He, Xihui; Han, Nanyin; Xu, Ruxiang

2013-08-01

Although single-wall carbon nanohorns (SWNHs) have been demonstrated to accumulate to cytotoxic levels within organs of various animal models and cell types, they have been exploited for cancer therapies. The role of SWNHs in human glioma cell lines was unclear. To address this question, the research about direct role of SWNHs on the growth, proliferation, and apoptosis of human glioma cell lines (U87, U251, and U373) had been performed. Our results indicate that particle size of SWNHs in water is between 342 and 712 nm, the films of SEM show that SWNHs on PS surface are individual particles. SWNHs significantly delayed mitotic entry of human glioma cell lines cells, and inhibited its proliferation in a time- and dose-dependent manner. SWNHs induced a significant increase in G1 phase and inhibition of S phase followed the gradually increasing concentrations. SWNHs in human glioma cell lines cells significantly induced apoptosis followed by their gradually increasing concentrations. The TEM images showed that individual spherical SWNHs particles smaller than 100 nm in diameters were localized inside lysosomes of human glioma cell lines. SWNHs inhibited mitotic entry, growth, and proliferation of human glioma cell lines, and promoted its apoptosis. SWNHs may be a novel opportunity or method for the research on treatment of human glioma.

Aspartame-induced apoptosis in PC12 cells

OpenAIRE

Horio, Yukari; Sun, Yongkun; Liu, Chuang; Saito, Takeshi; Kurasaki, Masaaki

2014-01-01

Aspartame is an artificial sweetner added to many low-calorie foods. The safety of aspartame remains controversial even though there are many studies on its risks. In this study, to understand the physiological effects of trace amounts of artificial sweetners on cells, the effects of aspartame on apoptosis were investigated using a PC12 cell system. In addition, the mechanism of apoptosis induced by aspartame in PC12 cells and effects on apoptotic factors such as cytochrome c, apoptosis-induc...

Lithium protects ethanol-induced neuronal apoptosis

International Nuclear Information System (INIS)

Zhong Jin; Yang Xianlin; Yao Weiguo; Lee Weihua

2006-01-01

Lithium is widely used for the treatment of bipolar disorder. Recent studies have demonstrated its neuroprotective effect. Ethanol is a potent neurotoxin that is particularly harmful to the developing nervous system. In this study, we evaluated lithium's neuroprotection against ethanol-induced apoptosis. Transient exposure of infant mice to ethanol caused apoptotic cell death in brain, which was prevented significantly by administering a low dose of lithium 15 min later. In cultured cerebellar granule neurons, ethanol-induced apoptosis and activation of caspase-3/9, both of which were prevented by lithium. However, lithium's protection is not mediated by its commonly known inhibition of glycogen synthase3β, because neither ethanol nor lithium has significant effects on the phosphorylation of Akt (ser473) or GSK3β (ser9). In addition, the selective GSK-3β inhibitor SB-415286 was unable to prevent ethanol-induced apoptosis. These data suggest lithium may be used as a potential preventive measure for ethanol-induced neurological deficits

Activating transcription factor 4 underlies the pathogenesis of arsenic trioxide-mediated impairment of macrophage innate immune functions

Energy Technology Data Exchange (ETDEWEB)

Srivastava, Ritesh K.; Li, Changzhao [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Wang, Yong [Department of Medicine, University of Alabama at Birmingham, Birmingham, AL (United States); Weng, Zhiping; Elmets, Craig A. [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States); Harrod, Kevin S. [Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL (United States); Deshane, Jessy S., E-mail: treena@uab.edu [Department of Medicine, University of Alabama at Birmingham, Birmingham, AL (United States); Athar, Mohammad, E-mail: mathar@uab.edu [Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL (United States)

2016-10-01

Chronic arsenic exposure to humans is considered immunosuppressive with augmented susceptibility to several infectious diseases. The exact molecular mechanisms, however, remain unknown. Earlier, we showed the involvement of unfolded protein response (UPR) signaling in arsenic-mediated impairment of macrophage functions. Here, we show that activating transcription factor 4 (ATF4), a UPR transcription factor, regulates arsenic trioxide (ATO)-mediated dysregulation of macrophage functions. In ATO-treated ATF4{sup +/+} wild-type mice, a significant down-regulation of CD11b expression was associated with the reduced phagocytic functions of peritoneal and lung macrophages. This severe immuno-toxicity phenotype was not observed in ATO-treated ATF4{sup +/−} heterozygous mice. To confirm these observations, we demonstrated in Raw 264.7 cells that ATF4 knock-down rescues ATO-mediated impairment of macrophage functions including cytokine production, bacterial engulfment and clearance of engulfed bacteria. Sustained activation of ATF4 by ATO in macrophages induces apoptosis, while diminution of ATF4 expression protects against ATO-induced apoptotic cell death. Raw 264.7 cells treated with ATO also manifest dysregulated Ca{sup ++} homeostasis. ATO induces Ca{sup ++}-dependent calpain-1 and caspase-12 expression which together regulated macrophage apoptosis. Additionally, apoptosis was also induced by mitochondria-regulated pathway. Restoring ATO-impaired Ca{sup ++} homeostasis in ER/mitochondria by treatments with the inhibitors of inositol 1,4,5-trisphosphate receptor (IP3R) and voltage-dependent anion channel (VDAC) attenuate innate immune functions of macrophages. These studies identify a novel role for ATF4 in underlying pathogenesis of macrophage dysregulation and immuno-toxicity of arsenic. - Highlights: • ATF4 regulates arsenic-mediated impairment in macrophage functions. • Arsenic-mediated alterations in pulmonary macrophage are diminished in ATF4{sup +/−} mice

Activating transcription factor 4 underlies the pathogenesis of arsenic trioxide-mediated impairment of macrophage innate immune functions

International Nuclear Information System (INIS)

Srivastava, Ritesh K.; Li, Changzhao; Wang, Yong; Weng, Zhiping; Elmets, Craig A.; Harrod, Kevin S.; Deshane, Jessy S.; Athar, Mohammad

2016-01-01

Chronic arsenic exposure to humans is considered immunosuppressive with augmented susceptibility to several infectious diseases. The exact molecular mechanisms, however, remain unknown. Earlier, we showed the involvement of unfolded protein response (UPR) signaling in arsenic-mediated impairment of macrophage functions. Here, we show that activating transcription factor 4 (ATF4), a UPR transcription factor, regulates arsenic trioxide (ATO)-mediated dysregulation of macrophage functions. In ATO-treated ATF4 +/+ wild-type mice, a significant down-regulation of CD11b expression was associated with the reduced phagocytic functions of peritoneal and lung macrophages. This severe immuno-toxicity phenotype was not observed in ATO-treated ATF4 +/− heterozygous mice. To confirm these observations, we demonstrated in Raw 264.7 cells that ATF4 knock-down rescues ATO-mediated impairment of macrophage functions including cytokine production, bacterial engulfment and clearance of engulfed bacteria. Sustained activation of ATF4 by ATO in macrophages induces apoptosis, while diminution of ATF4 expression protects against ATO-induced apoptotic cell death. Raw 264.7 cells treated with ATO also manifest dysregulated Ca ++ homeostasis. ATO induces Ca ++ -dependent calpain-1 and caspase-12 expression which together regulated macrophage apoptosis. Additionally, apoptosis was also induced by mitochondria-regulated pathway. Restoring ATO-impaired Ca ++ homeostasis in ER/mitochondria by treatments with the inhibitors of inositol 1,4,5-trisphosphate receptor (IP3R) and voltage-dependent anion channel (VDAC) attenuate innate immune functions of macrophages. These studies identify a novel role for ATF4 in underlying pathogenesis of macrophage dysregulation and immuno-toxicity of arsenic. - Highlights: • ATF4 regulates arsenic-mediated impairment in macrophage functions. • Arsenic-mediated alterations in pulmonary macrophage are diminished in ATF4 +/− mice. • Changes in macrophage

Indomethacin-Enhanced Anticancer Effect of Arsenic Trioxide in A549 Cell Line: Involvement of Apoptosis and Phospho-ERK and p38 MAPK Pathways

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Ali Mandegary

2013-01-01

Full Text Available Background. Focusing on novel drug combinations that target different pathways especially apoptosis and MAPK could be a rationale for combination therapy in successful treatment of lung cancer. Concurrent use of cyclooxygenase (COX inhibitors with arsenic trioxide (ATO might be a possible treatment option. Methods. Cytotoxicity of ATO, dexamethasone (Dex, celecoxib (Cel, and Indomethacin (Indo individually or in combination was determined at 24, 48, and 72 hrs in A549 lung cancer cells. The COX-2 gene and protein expression, MAPK pathway proteins, and caspase-3 activity were studied for the most cytotoxic combinations. Results. The IC50s of ATO and Indo were 68.7 μmol/L and 396.5 μmol/L, respectively. Treatment of cells with combinations of clinically relevant concentrations of ATO and Indo resulted in greater growth inhibition and apoptosis induction than did either agent alone. Caspase-3 activity was considerably high in the presence of ATO and Indo but showed no difference in single or combination use. Phosphorylation of p38 and ERK1/2 was remarkable in the concurrent presence of both drugs. Conclusions. Combination therapy with ATO and Indo exerted a very potent in vitro cytotoxic effect against A549 lung cancer cells. Activation of ERK and p38 pathways might be the mechanism of higher cytotoxic effect of ATO-Indo combination.

Genome-wide high-resolution mapping of UV-induced mitotic recombination events in Saccharomyces cerevisiae.

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Yi Yin

2013-10-01

Full Text Available In the yeast Saccharomyces cerevisiae and most other eukaryotes, mitotic recombination is important for the repair of double-stranded DNA breaks (DSBs. Mitotic recombination between homologous chromosomes can result in loss of heterozygosity (LOH. In this study, LOH events induced by ultraviolet (UV light are mapped throughout the genome to a resolution of about 1 kb using single-nucleotide polymorphism (SNP microarrays. UV doses that have little effect on the viability of diploid cells stimulate crossovers more than 1000-fold in wild-type cells. In addition, UV stimulates recombination in G1-synchronized cells about 10-fold more efficiently than in G2-synchronized cells. Importantly, at high doses of UV, most conversion events reflect the repair of two sister chromatids that are broken at approximately the same position whereas at low doses, most conversion events reflect the repair of a single broken chromatid. Genome-wide mapping of about 380 unselected crossovers, break-induced replication (BIR events, and gene conversions shows that UV-induced recombination events occur throughout the genome without pronounced hotspots, although the ribosomal RNA gene cluster has a significantly lower frequency of crossovers.

Hyperthermia: an effective strategy to induce apoptosis in cancer cells.

Science.gov (United States)

Ahmed, Kanwal; Tabuchi, Yoshiaki; Kondo, Takashi

2015-11-01

Heat has been used as a medicinal and healing modality throughout human history. The combination of hyperthermia (HT) with radiation and anticancer agents has been used clinically and has shown positive results to a certain extent. However, the clinical results of HT treatment alone have been only partially satisfactory. Cell death following HT treatment is a function of both temperature and treatment duration. HT induces cancer cell death through apoptosis; the degree of apoptosis and the apoptotic pathway vary in different cancer cell types. HT-induced reactive oxygen species production are responsible for apoptosis in various cell types. However, the underlying mechanism of signal transduction and the genes related to this process still need to be elucidated. In this review, we summarize the molecular mechanism of apoptosis induced by HT, enhancement of heat-induced apoptosis, and the genetic network involved in HT-induced apoptosis.

3,3'-diindolylmethane potentiates tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis of gastric cancer cells.

Science.gov (United States)

Ye, Yang; Miao, Shuhan; Wang, Yan; Zhou, Jianwei; Lu, Rongzhu

2015-05-01

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) specifically kills cancer cells without destroying the majority of healthy cells. However, numerous types of cancer cell, including gastric cancer cells, tend to be resistant to TRAIL. The bioactive product 3,3'-diindolylmethane (DIM), which is derived from cruciferous vegetables, is also currently recognized as a candidate anticancer agent. In the present study, a Cell Counting Kit 8 cell growth assay and an Annexin V-fluorescein isothiocyanate apoptosis assay were performed to investigate the potentiating effect of DIM on TRAIL-induced apoptosis in gastric cancer cells, and the possible mechanisms of this potentiation. The results obtained demonstrated that, compared with TRAIL or DIM treatment alone, co-treatment with TRAIL (25 or 50 ng/ml) and DIM (10 µmol/l) induced cytotoxic and apoptotic effects in BGC-823 and SGC-7901 gastric cancer cells. Furthermore, western blot analysis revealed that the protein expression levels of death receptor 5 (DR5), CCAAT/enhancer binding protein homologous protein (CHOP) and glucose-regulated protein 78 (GRP78) were upregulated in the co-treated gastric cancer cells. To the best of our knowledge, the present study is the first to provide evidence that DIM sensitizes TRAIL-induced inhibition of proliferation and apoptosis in gastric cancer cells, accompanied by the upregulated expression of DR5, CHOP and GRP78 proteins, which may be involved in endoplasmic reticulum stress mechanisms.

Apoptosis signal-regulating kinase 1 mediates denbinobin-induced apoptosis in human lung adenocarcinoma cells

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Pan Shiow-Lin

2009-05-01

Full Text Available Abstract In the present study, we explore the role of apoptosis signal-regulating kinase 1 (ASK1 in denbinobin-induced apoptosis in human lung adenocarcinoma (A549 cells. Denbinobin-induced cell apoptosis was attenuated by an ASK1 dominant-negative mutant (ASK1DN, two antioxidants (N-acetyl-L-cysteine (NAC and glutathione (GSH, a c-Jun N-terminal kinase (JNK inhibitor (SP600125, and an activator protein-1 (AP-1 inhibitor (curcumin. Treatment of A549 cells with denbinobin caused increases in ASK1 activity and reactive oxygen species (ROS production, and these effects were inhibited by NAC and GSH. Stimulation of A549 cells with denbinobin caused JNK activation; this effect was markedly inhibited by NAC, GSH, and ASK1DN. Denbinobin induced c-Jun phosphorylation, the formation of an AP-1-specific DNA-protein complex, and Bim expression. Bim knockdown using a bim short interfering RNA strategy also reduced denbinobin-induced A549 cell apoptosis. The denbinobin-mediated increases in c-Jun phosphorylation and Bim expression were inhibited by NAC, GSH, SP600125, ASK1DN, JNK1DN, and JNK2DN. These results suggest that denbinobin might activate ASK1 through ROS production to cause JNK/AP-1 activation, which in turn induces Bim expression, and ultimately results in A549 cell apoptosis.

UV-induced mitotic recombination and its dependence on photoreactivation and liquid holding in the rad6-1 mutant of Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Haladus, E.; Zuk, J.

1980-01-01

Spontaneous and UV-induced mitotic recombination was compared in diploids homozygous for rad6-1 mutation and in the wild-type strain carrying heterozygous markers for detecting gene conversion (hom 2-1, hom 2-2) and crossing over (ade 1, ade 2). Diploids homozygous for rad6-1 mutation were characterised by an elevated level of spontaneous and UV-induced mitotic recombination, particularly the intergenic events. Exposure of UV-irradiated strains to visible light resulted in an increased survival and decreased level of mitotic recombination. Liquid holding (LH) differentially affected frequency of mitotic intergenic and intragenic recombination in mutant and wild-type strains, being without any significant effect on cell survival. In a mutant strain intragenic recombination is significantly increased, intergenic only slightly. In the wild-type strain intragenic recombination is slightly decreased but intergenic is not changed by LH. Visible light applied after LH had no effect on survival and mitotic recombination in the wild type, while in the mutant strain photoreactivability of survival was fully preserved and accompanied by a decrease in the frequency of intragenic and intergenic recombination. The results suggest that metabolic pathways responsible for restoring cell survival are independent of or only partly overlapping with those concerning recombination events. (orig.) [de

The mitochondria-mediate apoptosis of Lepidopteran cells induced by azadirachtin.

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Jingfei Huang

Full Text Available Mitochondria have been shown to play an important role in apoptosis using mammalian cell lines. However, this seems not to be the case in Drosophila, an insect model organism; thus more in-depth studies of insect cell apoptosis are necessary. In the present study, mitochondrial involvement during azadirachtin- and camptothecin-induced apoptosis in Spodoptera frugiperda Sf9 cells (isolated from Spodoptera frugiperda pupal ovarian tissue was investigated. The results showed that both azadirachtin and camptothecin could induce apoptosis in Sf9 cells. Reactive oxygen species (ROS generation, activation of mitochondrial permeability transition pores (MPTPs and loss of mitochondrial membrane potential (MMP were observed very early during apoptosis and were followed subsequently by the release of cytochrome-c from the mitochondria. Furthermore, the results also revealed that the opening of MPTPs and the loss of MMP induced by azadirachtin could be significantly inhibited by the permeability transition pore (PTP inhibitor cyclosporin A (CsA, which was used to identify the key role of mitochondria in the apoptosis of Sf9 cells. However, in camptothecin-treated Sf9 cells, CsA could not suppress the opening of MPTPs and the loss of MMP when apoptosis was induced. The data from caspase-3 and caspase-9 activity assays and detection of apoptosis by morphological observation and flow cytometry also uncovered the different effect of CsA on the two botanical apoptosis inducers. Although different mechanisms of apoptosis induction exist, our study revealed that mitochondria play a crucial role in insect cell line apoptosis.

The mitochondria-mediate apoptosis of Lepidopteran cells induced by azadirachtin.

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Huang, Jingfei; Lv, Chaojun; Hu, Meiying; Zhong, Guohua

2013-01-01

Mitochondria have been shown to play an important role in apoptosis using mammalian cell lines. However, this seems not to be the case in Drosophila, an insect model organism; thus more in-depth studies of insect cell apoptosis are necessary. In the present study, mitochondrial involvement during azadirachtin- and camptothecin-induced apoptosis in Spodoptera frugiperda Sf9 cells (isolated from Spodoptera frugiperda pupal ovarian tissue) was investigated. The results showed that both azadirachtin and camptothecin could induce apoptosis in Sf9 cells. Reactive oxygen species (ROS) generation, activation of mitochondrial permeability transition pores (MPTPs) and loss of mitochondrial membrane potential (MMP) were observed very early during apoptosis and were followed subsequently by the release of cytochrome-c from the mitochondria. Furthermore, the results also revealed that the opening of MPTPs and the loss of MMP induced by azadirachtin could be significantly inhibited by the permeability transition pore (PTP) inhibitor cyclosporin A (CsA), which was used to identify the key role of mitochondria in the apoptosis of Sf9 cells. However, in camptothecin-treated Sf9 cells, CsA could not suppress the opening of MPTPs and the loss of MMP when apoptosis was induced. The data from caspase-3 and caspase-9 activity assays and detection of apoptosis by morphological observation and flow cytometry also uncovered the different effect of CsA on the two botanical apoptosis inducers. Although different mechanisms of apoptosis induction exist, our study revealed that mitochondria play a crucial role in insect cell line apoptosis.

Andrographolide induces apoptotic and non-apoptotic death and enhances tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in gastric cancer cells.

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Lim, Sung-Chul; Jeon, Ho Jong; Kee, Keun Hong; Lee, Mi Ja; Hong, Ran; Han, Song Iy

2017-05-01

Andrographolide, a natural compound isolated from Andrographis paniculata , has been reported to possess antitumor activity. In the present study, the effect of andrographolide in human gastric cancer (GC) cells was investigated. Andrographolide induced cell death with apoptotic and non-apoptotic features. At a low concentration, andrographolide potentiated apoptosis and reduction of clonogenicity triggered by recombinant human tumor necrosis factor-related apoptosis-inducing ligand (rhTRAIL). Exposure of GC cells to andrographolide altered the expression level of several growth-inhibiting and apoptosis-regulating proteins, including death receptors. It was demonstrated that activity of the TRAIL-R2 (DR5) pathway was critical in the development of andrographolide-mediated rhTRAIL sensitization, since its inhibition significantly reduced the extent of apoptosis induced by the combination of rhTRAIL and andrographolide. In addition, andrographolide increased reactive oxygen species (ROS) generation in a dose-dependent manner. N-acetyl cysteine prevented andrographolide-mediated DR5 induction and the apoptotic effect induced by the combination of rhTRAIL and andrographolide. Collectively, the present study demonstrated that andrographolide enhances TRAIL-induced apoptosis through induction of DR5 expression. This effect appears to involve ROS generation in GCs.

Overexpression of BAG3 Attenuates Hypoxia-Induced Cardiomyocyte Apoptosis by Inducing Autophagy

Directory of Open Access Journals (Sweden)

Jiankai Zhang

2016-07-01

Full Text Available Background: Hypoxia is a well-known factor in the promotion of apoptosis, which contributes to the development of numerous cardiac diseases, such as heart failure and myocardial infarction. Inhibiting apoptosis is an important therapeutic strategy for the treatment of related heart diseases caused by ischemia/hypoxic injury. Previous studies have demonstrated that BAG3 plays an important role in cardiomyocyte apoptosis and survival. However, the role of BAG3 in hypoxia-induced cardiomyocyte apoptosis remains to be clarified. Here, we demonstrate that BAG3 is induced by hypoxia stimuli in cultured cardiomyocytes. Methods: BAG3 expression level was measured in H9c2 cells treated with hypoxia for 48 h. Cell proliferation and apoptosis were tested using MTT assay and Annexin V FITC-PI staining assay, respectively. The mRNA or protein expression level of BAG3, LC3-I, LC3-II, Atg5, NF-κB p65 and phosphorylated NF-κB p65 were assessed by qRT-PCR and western blot assay, respectively. Resluts: Overexpression of BAG3 inhibited cell apoptosis and promoted proliferation in hypoxia-injured H9c2 cells. Furthermore, autophagy and NF-κB were activated by BAG3 overexpression, and the NF-κB inhibitor PDTC could inhibit the activation of autophagy induced by BAG3 overexpression. In addition, the autophagy inhibitor 3-MA partly impeded the inhibitory effect of BAG3 on hypoxia-induced cardiomyocyte apoptosis. Conclusion: these results suggested that overexpression of BAG3 promoted cell proliferation and inhibited apoptosis by activating autophagy though the NF-κB signaling pathway in hypoxia-injured cardiomyocytes.

Verocytotoxin-induced apoptosis of human microvascular endothelial cells.

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Pijpers, A H; van Setten, P A; van den Heuvel, L P; Assmann, K J; Dijkman, H B; Pennings, A H; Monnens, L A; van Hinsbergh, V W

2001-04-01

The pathogenesis of the epidemic form of hemolytic uremic syndrome is characterized by endothelial cell damage. In this study, the role of apoptosis in verocytotoxin (VT)-mediated endothelial cell death in human glomerular microvascular endothelial cells (GMVEC), human umbilical vein endothelial cells, and foreskin microvascular endothelial cells (FMVEC) was investigated. VT induced apoptosis in GMVEC and human umbilical vein endothelial cells when the cells were prestimulated with the inflammatory mediator tumor necrosis factor-alpha (TNF-alpha). FMVEC displayed strong binding of VT and high susceptibility to VT under basal conditions, which made them suitable for the study of VT-induced apoptosis without TNF-alpha interference. On the basis of functional (flow cytometry and immunofluorescence microscopy using FITC-conjugated annexin V and propidium iodide), morphologic (transmission electron microscopy), and molecular (agarose gel electrophoresis of cellular DNA fragments) criteria, it was documented that VT induced programmed cell death in microvascular endothelial cells in a dose- and time-dependent manner. Furthermore, whereas partial inhibition of protein synthesis by VT was associated with a considerable number of apoptotic cells, comparable inhibition of protein synthesis by cycloheximide was not. This suggests that additional pathways, independent of protein synthesis inhibition, may be involved in VT-mediated apoptosis in microvascular endothelial cells. Specific inhibition of caspases by Ac-Asp-Glu-Val-Asp-CHO, but not by Ac-Tyr-Val-Ala-Asp-CHO, was accompanied by inhibition of VT-induced apoptosis in FMVEC and TNF-alpha-treated GMVEC. These data indicate that VT can induce apoptosis in human microvascular endothelial cells.

Fas-induced apoptosis in malnourished infants

African Journals Online (AJOL)

EL-HAKIM

deprivation in animals, including man11. Factor of apoptosis signal (Fas) induces apoptosis in activated T cells when they are repeatedly stimulated by antigen and functions to maintain T cell tolerance by deleting auto reactive cells12. The functional role of Fas (CD95) in the immune system has been examined in a variety ...

Ketamine-induced apoptosis in cultured rat cortical neurons

International Nuclear Information System (INIS)

Takadera, Tsuneo; Ishida, Akira; Ohyashiki, Takao

2006-01-01

Recent data suggest that anesthetic drugs cause neurodegeneration during development. Ketamine is frequently used in infants and toddlers for elective surgeries. The purpose of this study is to determine whether glycogen synthase kinase-3 (GSK-3) is involved in ketamine-induced apoptosis. Ketamine increased apoptotic cell death with morphological changes which were characterized by cell shrinkage, nuclear condensation or fragmentation. In addition, insulin growth factor-1 completely blocked the ketamine-induced apoptotic cell death. Ketamine decreased Akt phosphorylation. GSK-3 is known as a downstream target of Akt. The selective inhibitors of GSK-3 prevented the ketamine-induced apoptosis. Moreover, caspase-3 activation was accompanied by the ketamine-induced cell death and inhibited by the GSK-3 inhibitors. These results suggest that activation of GSK-3 is involved in ketamine-induced apoptosis in rat cortical neurons

Troglitazone induced apoptosis via PPARγ activated POX-induced ROS formation in HT29 cells.

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Wang, Jing; Lv, XiaoWen; Shi, JiePing; Hu, XiaoSong; DU, YuGuo

2011-08-01

In order to investigate the potential mechanisms in troglitazone-induced apoptosis in HT29 cells, the effects of PPARγ and POX-induced ROS were explored. [3- (4, 5)-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay, Annexin V and PI staining using FACS, plasmid transfection, ROS formation detected by DCFH staining, RNA interference, RT-PCR & RT-QPCR, and Western blotting analyses were employed to investigate the apoptotic effect of troglitazone and the potential role of PPARγ pathway and POX-induced ROS formation in HT29 cells. Troglitazone was found to inhibit the growth of HT29 cells by induction of apoptosis. During this process, mitochondria related pathways including ROS formation, POX expression and cytochrome c release increased, which were inhibited by pretreatment with GW9662, a specific antagonist of PPARγ. These results illustrated that POX upregulation and ROS formation in apoptosis induced by troglitazone was modulated in PPARγ-dependent pattern. Furthermore, the inhibition of ROS and apoptosis after POX siRNA used in troglitazone-treated HT29 cells indicated that POX be essential in the ROS formation and PPARγ-dependent apoptosis induced by troglitazone. The findings from this study showed that troglitazone-induced apoptosis was mediated by POX-induced ROS formation, at least partly, via PPARγ activation. Copyright © 2011 The Editorial Board of Biomedical and Environmental Sciences. Published by Elsevier B.V. All rights reserved.

[Advances in Parvovirus Non-structural Protein NS1 Induced Apoptosis].

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Tu, Mengyu; Liu, Fei; Chen, Shun; Wang, Mingshu; Cheng, Anchun

2015-11-01

Until now, more than seventeen parvovirus have been reported which can infect mammals and poultries. The infected cells appeared different properties of apoptosis and death, present a typical cytopathic effect. NS1 is a major nonstructural protein of parvovirus, with a conservative structure and function, which plays an important role in the viral life cycle. In addition to the influence on viral replication, the NS1 also participates in apoptosis induced by viruses. Parvovirus induced apoptosis which is mainly mediated by mitochondrial pathway, this review summarized the latest research progresses of parvovirus induced apoptosis.

Protein Kinase C-{delta} mediates down-regulation of heterogeneous nuclear ribonucleoprotein K protein: involvement in apoptosis induction

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Gao, Feng-Hou [NO.3 People' s Hospital affiliated to Shanghai Jiao-Tong University School of Medicine (SJTU-SM), Shanghai 201900 (China); The Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao-Tong University School of Medicine (SJTU-SM), Shanghai 200025 (China); Wu, Ying-Li [The Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao-Tong University School of Medicine (SJTU-SM), Shanghai 200025 (China); Zhao, Meng [Institute of Health Science, SJTU-SM/Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai (China); Liu, Chuan-Xu; Wang, Li-Shun [The Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao-Tong University School of Medicine (SJTU-SM), Shanghai 200025 (China); Chen, Guo-Qiang, E-mail: chengq@shsmu.edu.cn [The Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao-Tong University School of Medicine (SJTU-SM), Shanghai 200025 (China); Institute of Health Science, SJTU-SM/Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai (China)

2009-11-15

We reported previously that NSC606985, a camptothecin analogue, induces apoptosis of acute myeloid leukemia (AML) cells through proteolytic activation of protein kinase C delta ({Delta}PKC-{delta}). By subcellular proteome analysis, heterogeneous nuclear ribonucleoprotein K (hnRNP K) was identified as being significantly down-regulated in NSC606985-treated leukemic NB4 cells. HnRNP K, a docking protein for DNA, RNA, and transcriptional or translational molecules, is implicated in a host of processes involving the regulation of gene expression. However, the molecular mechanisms of hnRNP K reduction and its roles during apoptosis are still not understood. In the present study, we found that, following the appearance of the {Delta}PKC-{delta}, hnRNP K protein was significantly down-regulated in NSC606985, doxorubicin, arsenic trioxide and ultraviolet-induced apoptosis. We further provided evidence that {Delta}PKC-{delta} mediated the down-regulation of hnRNP K protein during apoptosis: PKC-{delta} inhibitor could rescue the reduction of hnRNP K; hnRNP K failed to be decreased in PKC-{delta}-deficient apoptotic KG1a cells; conditional induction of {Delta}PKC-{delta} in U937T cells directly down-regulated hnRNP K protein. Moreover, the proteasome inhibitor also inhibited the down-regulation of hnRNP K protein by apoptosis inducer and the conditional expression of {Delta}PKC-{delta}. More intriguingly, the suppression of hnRNP K with siRNA transfection significantly induced apoptosis. To our knowledge, this is the first demonstration that proteolytically activated PKC-{delta} down-regulates hnRNP K protein in a proteasome-dependent manner, which plays an important role in apoptosis induction.

Cytoprotection by fructose and other ketohexoses during bile salt-induced apoptosis of hepatocytes.

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Zeid, I M; Bronk, S F; Fesmier, P J; Gores, G J

1997-01-01

Toxic bile salts cause hepatocyte necrosis at high concentrations and apoptosis at lower concentrations. Although fructose prevents bile salt-induced necrosis, the effect of fructose on bile salt-induced apoptosis is unclear. Our aim was to determine if fructose also protects against bile salt-induced apoptosis. Fructose inhibited glycochenodeoxycholate (GCDC)-induced apoptosis in a concentration-dependent manner with a maximum inhibition of 72% +/- 10% at 10 mmol/L. First, we determined if fructose inhibited apoptosis by decreasing adenosine triphosphate (ATP) and intracellular pH (pHi). Although fructose decreased ATP to effects, alterations in the expression of bcl-2, or metal chelation, we next determined if the poorly metabolized ketohexoses, tagatose and sorbose, also inhibited apoptosis; unexpectedly, both ketohexoses inhibited apoptosis. Because bile salt-induced apoptosis and necrosis are inhibited by fructose, these data suggest that similar processes initiate bile salt-induced hepatocyte necrosis and apoptosis. In contrast, acidosis, which inhibits necrosis, potentiates apoptosis. Thus, ketohexose-sensitive pathways appear to initiate both bile salt-induced cell apoptosis and necrosis, whereas dissimilar, pH-sensitive, effector mechanisms execute these two different cell death processes.

p53-independent early and late apoptosis is mediated by ceramide after exposure of tumor cells to photon or carbon ion irradiation

International Nuclear Information System (INIS)

Alphonse, Gersende; Maalouf, Mira; Battiston-Montagne, Priscillia; Ardail, Dominique; Beuve, Michaël; Rousson, Robert; Taucher-Scholz, Gisela; Fournier, Claudia; Rodriguez-Lafrasse, Claire

2013-01-01

To determine whether ceramide is responsible for the induction of p53-independent early or late apoptosis in response to high- and low-Linear-Energy-Transfer (LET) irradiation. Four cell lines displaying different radiosensitivities and p53-protein status were irradiated with photons or 33.4 or 184 keV/μm carbon ions. The kinetics of ceramide production was quantified by fluorescent microscopy or High-Performance-Liquid-Chromatogaphy and the sequence of events leading to apoptosis by flow cytometry. Regardless of the p53-status, both low and high-LET irradiation induced an early ceramide production in radiosensitive cells and late in the radioresistant. This production strongly correlated with the level of early apoptosis in radiosensitive cells and delayed apoptosis in the radioresistant ones, regardless of radiation quality, tumor type, radiosensitivity, or p53-status. Inhibition of caspase activity or ceramide production showed that, for both types of radiation, ceramide is essential for the initiation of early apoptosis in radiosensitive cells and late apoptosis following mitotic catastrophe in radioresistant cells. Ceramide is a determining factor in the onset of early and late apoptosis after low and high-LET irradiation and is the mediator of the p53-independent-apoptotic pathway. We propose that ceramide is the molecular bridge between mitotic catastrophe and the commitment phase of delayed apoptosis in response to irradiation

Overexpression of BAG3 Attenuates Hypoxia-Induced Cardiomyocyte Apoptosis by Inducing Autophagy.

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Zhang, Jiankai; He, Zhangyou; Xiao, Wenjian; Na, Qingqing; Wu, Tianxiu; Su, Kaixin; Cui, Xiaojun

2016-01-01

Hypoxia is a well-known factor in the promotion of apoptosis, which contributes to the development of numerous cardiac diseases, such as heart failure and myocardial infarction. Inhibiting apoptosis is an important therapeutic strategy for the treatment of related heart diseases caused by ischemia/hypoxic injury. Previous studies have demonstrated that BAG3 plays an important role in cardiomyocyte apoptosis and survival. However, the role of BAG3 in hypoxia-induced cardiomyocyte apoptosis remains to be clarified. Here, we demonstrate that BAG3 is induced by hypoxia stimuli in cultured cardiomyocytes. BAG3 expression level was measured in H9c2 cells treated with hypoxia for 48 h. Cell proliferation and apoptosis were tested using MTT assay and Annexin V FITC-PI staining assay, respectively. The mRNA or protein expression level of BAG3, LC3-I, LC3-II, Atg5, NF-x03BA;B p65 and phosphorylated NF-x03BA;B p65 were assessed by qRT-PCR and western blot assay, respectively. Resluts: Overexpression of BAG3 inhibited cell apoptosis and promoted proliferation in hypoxia-injured H9c2 cells. Furthermore, autophagy and NF-x03BA;B were activated by BAG3 overexpression, and the NF-x03BA;B inhibitor PDTC could inhibit the activation of autophagy induced by BAG3 overexpression. In addition, the autophagy inhibitor 3-MA partly impeded the inhibitory effect of BAG3 on hypoxia-induced cardiomyocyte apoptosis. these results suggested that overexpression of BAG3 promoted cell proliferation and inhibited apoptosis by activating autophagy though the NF-x03BA;B signaling pathway in hypoxia-injured cardiomyocytes. © 2016 The Author(s) Published by S. Karger AG, Basel.

Radiation-induced mitotic and meiotic aneuploidy in the yeast Saccharomyces cerevisiae.

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Parry, J M; Sharp, D; Tippins, R S; Parry, E M

1979-06-01

A number of genetic systems are described which in yeast may be used to monitor the induction of chromosome aneuploidy during both mitotic and meiotic cell division. Using these systems we have been able to demonstrate the induction of both monosomic and trisomic cells in mitotically dividing cells and disomic spores in meiotically dividing cells after both UV light and X-ray exposure. The frequency of UV-light-induced monosomic colonies were reduced by post-treatment with photoreactivity light and both UV-light- and X-ray-induced monosomic colonies were reduced by liquid holding post-treatment under non-nutrient conditions. Both responses indicate an involvement of DNA-repair mechanisms in the removal of lesions which may lead to monosomy in yeast. This was further confirmed by the response of an excision-defective yeast strain which showed considerably increased sensitivity to the induction of monosomic colonies by UV-light treatment at low doses. Yeast cultures irradiated at different stages of growth showed variation in their responses to both UV-light and X-rays, cells at the exponential phase of growth show maximum sensitivity to the induction of monosomic colonies at low doses whereas stationary phase cultures showed maximum induction of monosomic colonies at high does. The frequencies of X-ray-induced chromosome aneuploidy during meiosis leading to the production of disomic spores was shown to be dependent upon the stage of meiosis at which the yeast cells were exposed to radiation. Cells which had proceeded beyond the DNA synthetic stage of meiosis were shown to produce disomic spores at considerably lower radiation doses than those cells which had only recently been inoculated into sporulation medium. The results obtained suggest that the yeast sustem may be suitable for the study of sensitivities of the various stages of meiotic cell division to the induction of chromosome aneuploidy after radiation exposure.

Andrographolide sensitizes prostate cancer cells to TRAIL-induced apoptosis

Directory of Open Access Journals (Sweden)

Ruo-Jing Wei

2018-01-01

Full Text Available Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL is a promising agent for anticancer therapy. The identification of small molecules that can establish the sensitivity of prostate cancer (PCa cells to TRAIL-induced apoptosis is crucial for the targeted treatment of PCa. PC3, DU145, JAC-1, TsuPr1, and LNCaP cells were treated with Andrographolide (Andro and TRAIL, and the apoptosis was measured using the Annexin V/PI double staining method. Real time-polymerase chain reaction (PCR and Western blot analysis were performed to measure the expression levels of target molecules. RNA interference technique was used to down-regulate the expression of the target protein. We established a nude mouse xenograft model of PCa, which was used to measure the caspase-3 activity in the tumor cells using flow cytometry. In this research study, our results demonstrated that Andro preferentially increased the sensitivity of PCa cells to TRAIL-induced apoptosis at subtoxic concentrations, and the regulation mechanism was related to the up-regulation of DR4. In addition, it also increased the p53 expression and led to the generation of reactive oxygen species (ROS in the cells. Further research revealed that the DR4 inhibition, p53 expression, and ROS generation can significantly reduce the apoptosis induced by the combination of TRAIL and Andro in PCa cells. In conclusion, Andro increases the sensitivity of PCa cells to TRAIL-induced apoptosis through the generation of ROS and up-regulation of p53 and then promotes PCa cell apoptosis associated with the activation of DR4.

Hypoxia-induced p53 modulates both apoptosis and radiosensitivity via AKT

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Leszczynska, Katarzyna B.; Foskolou, Iosifina P.; Abraham, Aswin G.; Anbalagan, Selvakumar; Tellier, Céline; Haider, Syed; Span, Paul N.; O’Neill, Eric E.; Buffa, Francesca M.; Hammond, Ester M.

2015-01-01

Restoration of hypoxia-induced apoptosis in tumors harboring p53 mutations has been proposed as a potential therapeutic strategy; however, the transcriptional targets that mediate hypoxia-induced p53-dependent apoptosis remain elusive. Here, we demonstrated that hypoxia-induced p53-dependent apoptosis is reliant on the DNA-binding and transactivation domains of p53 but not on the acetylation sites K120 and K164, which, in contrast, are essential for DNA damage–induced, p53-dependent apoptosis. Evaluation of hypoxia-induced transcripts in multiple cell lines identified a group of genes that are hypoxia-inducible proapoptotic targets of p53, including inositol polyphosphate-5-phosphatase (INPP5D), pleckstrin domain–containing A3 (PHLDA3), sulfatase 2 (SULF2), B cell translocation gene 2 (BTG2), cytoplasmic FMR1-interacting protein 2 (CYFIP2), and KN motif and ankyrin repeat domains 3 (KANK3). These targets were also regulated by p53 in human cancers, including breast, brain, colorectal, kidney, bladder, and melanoma cancers. Downregulation of these hypoxia-inducible targets associated with poor prognosis, suggesting that hypoxia-induced apoptosis contributes to p53-mediated tumor suppression and treatment response. Induction of p53 targets, PHLDA3, and a specific INPP5D transcript mediated apoptosis in response to hypoxia through AKT inhibition. Moreover, pharmacological inhibition of AKT led to apoptosis in the hypoxic regions of p53-deficient tumors and consequently increased radiosensitivity. Together, these results identify mediators of hypoxia-induced p53-dependent apoptosis and suggest AKT inhibition may improve radiotherapy response in p53-deficient tumors. PMID:25961455

Arsenic Trioxide Injection

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... people who have not been helped by other types of chemotherapy or whose condition has improved but then worsened following treatment with other types of chemotherapy. Arsenic trioxide is in a class of medications ...

Paclitaxel and the dietary flavonoid fisetin: a synergistic combination that induces mitotic catastrophe and autophagic cell death in A549 non-small cell lung cancer cells.

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Klimaszewska-Wisniewska, Anna; Halas-Wisniewska, Marta; Tadrowski, Tadeusz; Gagat, Maciej; Grzanka, Dariusz; Grzanka, Alina

2016-01-01

The use of the dietary polyphenols as chemosensitizing agents to enhance the efficacy of conventional cytostatic drugs has recently gained the attention of scientists and clinicians as a plausible approach for overcoming the limitations of chemotherapy (e.g. drug resistance and cytotoxicity). The aim of this study was to investigate whether a naturally occurring diet-based flavonoid, fisetin, at physiologically attainable concentrations, could act synergistically with clinically achievable doses of paclitaxel to produce growth inhibitory and/or pro-death effects on A549 non-small cell lung cancer cells, and if it does, what mechanisms might be involved. The drug-drug interactions were analyzed based on the combination index method of Chou and Talalay and the data from MTT assays. To provide some insights into the mechanism underlying the synergistic action of fisetin and paclitaxel, selected morphological, biochemical and molecular parameters were examined, including the morphology of cell nuclei and mitotic spindles, the pattern of LC3-II immunostaining, the formation of autophagic vacuoles at the electron and fluorescence microscopic level, the disruption of cell membrane asymmetry/integrity, cell cycle progression and the expression level of LC3-II, Bax, Bcl-2 and caspase-3 mRNA. Here, we reported the first experimental evidence for the existence of synergism between fisetin and paclitaxel in the in vitro model of non-small cell lung cancer. This synergism was, at least partially, ascribed to the induction of mitotic catastrophe. The switch from the cytoprotective autophagy to the autophagic cell death was also implicated in the mechanism of the synergistic action of fisetin and paclitaxel in the A549 cells. In addition, we revealed that the synergism between fisetin and paclitaxel was cell line-specific as well as that fisetin synergizes with arsenic trioxide, but not with mitoxantrone and methotrexate in the A549 cells. Our results provide rationale for

Oxidative Stress-Responsive Apoptosis Inducing Protein (ORAIP) Plays a Critical Role in High Glucose-Induced Apoptosis in Rat Cardiac Myocytes and Murine Pancreatic β-Cells.

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Yao, Takako; Fujimura, Tsutomu; Murayama, Kimie; Okumura, Ko; Seko, Yoshinori

2017-10-18

We previously identified a novel apoptosis-inducing humoral factor in the conditioned medium of hypoxic/reoxygenated-cardiac myocytes. We named this novel post-translationally-modified secreted-form of eukaryotic translation initiation factor 5A Oxidative stress-Responsive Apoptosis-Inducing Protein (ORAIP). We confirmed that myocardial ischemia/reperfusion markedly increased plasma ORAIP levels and rat myocardial ischemia/reperfusion injury was clearly suppressed by neutralizing anti-ORAIP monoclonal antibodies (mAbs) in vivo. In this study, to investigate the mechanism of cell injury of cardiac myocytes and pancreatic β-cells involved in diabetes mellitus (DM), we analyzed plasma ORAIP levels in DM model rats and the role of ORAIP in high glucose-induced apoptosis of cardiac myocytes in vitro. We also examined whether recombinant-ORAIP induces apoptosis in pancreatic β-cells. Plasma ORAIP levels in DM rats during diabetic phase were about 18 times elevated as compared with non-diabetic phase. High glucose induced massive apoptosis in cardiac myocytes (66.2 ± 2.2%), which was 78% suppressed by neutralizing anti-ORAIP mAb in vitro. Furthermore, recombinant-ORAIP clearly induced apoptosis in pancreatic β-cells in vitro. These findings strongly suggested that ORAIP plays a pivotal role in hyperglycemia-induced myocardial injury and pancreatic β-cell injury in DM. ORAIP will be a biomarker and a critical therapeutic target for cardiac injury and progression of DM itself.

Human retinal pigment epithelial cell-induced apoptosis in activated T cells

DEFF Research Database (Denmark)

Jørgensen, A; Wiencke, A K; la Cour, M

1998-01-01

human retinal pigment epithelial (RPE) cells can induce apoptosis in activated T cells. METHODS: Fas ligand (FasL) expression was detected by flow cytometry and immunohistochemistry. Cultured RPE cells were cocultured with T-cell lines and peripheral blood lymphocytes for 6 hours to 2 days. Induction...... of apoptosis was detected by 7-amino-actinomycin D and annexin V staining. RESULTS: Retinal pigment epithelial cells expressed FasL and induced apoptosis in activated Fas+ T cells. Blocking of Fas-FasL interaction with antibody strongly inhibited RPE-mediated T-cell apoptosis. Retinal pigment epithelial cells...... induced apoptosis in several activated T-cell populations and T-cell lines, including T-cell antigen receptor (TCR)-CD3-negative T-cell lines. In contrast, RPE cells induced little or no apoptosis in resting peripheral T cells. Major histocompatibility complex (MHC) class II monoclonal antibodies, which...

Radiation-induced apoptosis in F9 teratocarcinoma cells

International Nuclear Information System (INIS)

Langley, R.E.; Palayoor, S.T.; Coleman, C.N.; Bump, E.A.

1994-01-01

We have found that F9 murine teratocarcinoma cells undergo morphological changes and internucleosomal DNA fragmentation characteristic of apoptosis after exposure to ionizing radiation. We studied the time course, radiation dose-response, and the effects of protein and RNA synthesis inhibitors on this process. The response is dose dependent in the range 2-12 Gy. Internucleosomal DNA fragmentation can be detected as early as 6 h postirradiation and is maximal by 48 h. Cycloheximide, a protein synthesis inhibitor, and 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole, an RNA synthesis inhibitor, both induced internucleosomal DNA fragmentation in the unirradiated cells and enhanced radiation-induced DNA fragmentation. F9 cells can be induced to differentiate into cells resembling endoderm with retinoic acid. After irradiation, differentiated F9 cells exhibit less DNA fragmentation than stem cells. This indicates that ionizing radiation can induce apoptosis in non-lymphoid tumours. We suggest that embryonic tumour cells may be particularly susceptible to agents that induce apoptosis. (Author)

Radiation-induced apoptosis in F9 teratocarcinoma cells

Energy Technology Data Exchange (ETDEWEB)

Langley, R E; Palayoor, S T; Coleman, C N; Bump, E A [Joint Center for Radiation Therapy and Dana Farber Cancer Inst., Boston (United States)

1994-05-01

We have found that F9 murine teratocarcinoma cells undergo morphological changes and internucleosomal DNA fragmentation characteristic of apoptosis after exposure to ionizing radiation. We studied the time course, radiation dose-response, and the effects of protein and RNA synthesis inhibitors on this process. The response is dose dependent in the range 2-12 Gy. Internucleosomal DNA fragmentation can be detected as early as 6 h postirradiation and is maximal by 48 h. Cycloheximide, a protein synthesis inhibitor, and 5,6-dichloro-1-[beta]-D-ribofuranosylbenzimidazole, an RNA synthesis inhibitor, both induced internucleosomal DNA fragmentation in the unirradiated cells and enhanced radiation-induced DNA fragmentation. F9 cells can be induced to differentiate into cells resembling endoderm with retinoic acid. After irradiation, differentiated F9 cells exhibit less DNA fragmentation than stem cells. This indicates that ionizing radiation can induce apoptosis in non-lymphoid tumours. We suggest that embryonic tumour cells may be particularly susceptible to agents that induce apoptosis. (Author).

Beta-irradiation used for systemic radioimmunotherapy induces apoptosis and activates apoptosis pathways in leukaemia cells

International Nuclear Information System (INIS)

Friesen, Claudia; Lubatschofski, Annelie; Debatin, Klaus-Michael; Kotzerke, Joerg; Buchmann, Inga; Reske, Sven N.

2003-01-01

Beta-irradiation used for systemic radioimmunotherapy (RIT) is a promising treatment approach for high-risk leukaemia and lymphoma. In bone marrow-selective radioimmunotherapy, beta-irradiation is applied using iodine-131, yttrium-90 or rhenium-188 labelled radioimmunoconjugates. However, the mechanisms by which beta-irradiation induces cell death are not understood at the molecular level. Here, we report that beta-irradiation induced apoptosis and activated apoptosis pathways in leukaemia cells depending on doses, time points and dose rates. After beta-irradiation, upregulation of CD95 ligand and CD95 receptor was detected and activation of caspases resulting in apoptosis was found. These effects were completely blocked by the broad-range caspase inhibitor zVAD-fmk. In addition, irradiation-mediated mitochondrial damage resulted in perturbation of mitochondrial membrane potential, caspase-9 activation and cytochrome c release. Bax, a death-promoting protein, was upregulated and Bcl-x L , a death-inhibiting protein, was downregulated. We also found higher apoptosis rates and earlier activation of apoptosis pathways after gamma-irradiation in comparison to beta-irradiation at the same dose rate. Furthermore, irradiation-resistant cells were cross-resistant to CD95 and CD95-resistant cells were cross-resistant to irradiation, indicating that CD95 and irradiation used, at least in part, identical effector pathways. These findings demonstrate that beta-irradiation induces apoptosis and activates apoptosis pathways in leukaemia cells using both mitochondrial and death receptor pathways. Understanding the timing, sequence and molecular pathways of beta-irradiation-mediated apoptosis may allow rational adjustment of chemo- and radiotherapeutic strategies. (orig.)

The apoptosis of CHO cells induced by X-rays

International Nuclear Information System (INIS)

Lu Zhaohong; Zhao Jingyong; Zhu Mingqing; Shi Xijin; Wang Chunlei

2004-01-01

The work is to study the mechanism of toxic effects on reproductive system and apoptosis of Chinese hamster ovary (CHO) cells induced by X-rays. CHO cell was exposed to X-rays 2 to 20 Gy. Apoptosis and morphological changes of the cells were observed by fluorescent microscopy and flow cytometry analyzer with double staining with Annexin V/PI. The apoptosis could be observed at 24, 48 and 72h after the exposure, but it was more obvious 48 and 72 h after the exposure. Rate of the apoptosis increased along with radiation dose were elevated. Some morphological changes, such as irregular agglomerate of chromatins, pycnosis and periphery distribution of nuclei, crescent-moon-like cells, small apoptosis body, were observed. Radiation results DNA damage in the CHO cells, and the damage cannot be repaired, hence the induced cell apoptosis. (authors)

Sequential activation of proteases in radiation induced apoptosis

International Nuclear Information System (INIS)

Watters, D.; Waterhouse, N.

1997-01-01

Full text: Significant advances have been made in recent years in unraveling the molecular mechanisms of apoptosis particularly in relation to Fas- and TNF-mediated cell death, however there are considerable gaps in our knowledge of the processes involved in apoptosis induced by ionizing radiation. We have used the degradation of specific proteolytic targets in a pair of isogenic Burkitt's Iymphoma cells lines (BL30A, sensitive and BL30K resistant) to study the sequence of events in the execution of radiation-induced apoptosis. Fodrin can be cleaved to fragments of 150 kDa and 120 kDa. In the case of Fas-mediated apoptosis both cleavages are inhibited by the caspase inhibitor zVAD-fmk at 10 μM, a concentration which inhibits all the hallmarks of apoptosis. However in radiation-induced apoptosis, inhibition of the clevage of fodrin to the 150 kDa fragment requires 100 μM zVAD-fink while apoptosis itself is inhibited at 10 μM. This suggests that different enzymes are responsible for the generation of the 150 kDa fragment in the two models of apoptosis. Fodrin has been reported to be cleaved by μ-calpain to a 150 kDa fragment however, the involvement of μ-calpain in apoptosis has not yet been established. In murine fodrin there is a caspase cleavage site within 1 kDa of the calpain cleavage site. In vitro studies using purified enzymes showed that only caspase-3 and μ-calpain could cleave fodrin in untreated cell extracts to the same sized fragments as seen during apoptosis in vivo. We provide evidence for the early activation of μ-calpain after ionizing radiation in the sensitive BL30A cell line, and show that the time course of μ-calpain activation parallels that of the appearance of the 150 kDa fragment. Caspase-3 is activated much later and is likely to be responsible for the generation of the 120 kDa fragment. μ-Calpain was not activated in the resistant cell line. Based on these results we propose a model for the proteolytic cascade in radiation-induced

Neuroprotective effects of ganoderma lucidum polysaccharides against oxidative stress-induced neuronal apoptosis

Science.gov (United States)

Sun, Xin-zhi; Liao, Ying; Li, Wei; Guo, Li-mei

2017-01-01

Ganoderma lucidum polysaccharides have protective effects against apoptosis in neurons exposed to ischemia/reperfusion injury, but the mechanisms are unclear. The goal of this study was to investigate the underlying mechanisms of the effects of ganoderma lucidum polysaccharides against oxidative stress-induced neuronal apoptosis. Hydrogen peroxide (H2O2) was used to induce apoptosis in cultured cerebellar granule cells. In these cells, ganoderma lucidum polysaccharides remarkably suppressed H2O2-induced apoptosis, decreased expression of caspase-3, Bax and Bim and increased that of Bcl-2. These findings suggested that ganoderma lucidum polysaccharides regulate expression of apoptosis-associated proteins, inhibit oxidative stress-induced neuronal apoptosis and, therefore, have significant neuroprotective effects. PMID:28761429

Mitotic delay of irradiated cells and its connection with quantity of radiation injuries

International Nuclear Information System (INIS)

Lobachevskij, P.N.; Fominykh, E.V.

1989-01-01

The study is dedicated to development of mathematical approach to interpret radiation-induced mitosic delay. An assumption is made that mitotic delay is conditioned by discrete injuries distributed in cells according to stochasticity of interaction of radiation and target substance. It is supposed to consider the problem on injuries nature causing mitotic delay and to use the developed method for accounting the effect of radiation-induced mitotic delay on registered chromosomal aberration yield. 10 refs.; 2 figs.; 3 tabs

The role of hypoxia inducible factor 1 (HIF-1) in hypoxia induced apoptosis

NARCIS (Netherlands)

Greijer, A.E.; Wall, E. van der

2004-01-01

Apoptosis can be induced in response to hypoxia. The severity of hypoxia determines whether cells become apoptotic or adapt to hypoxia and survive. A hypoxic environment devoid of nutrients prevents the cell undergoing energy dependent apoptosis and cells become necrotic. Apoptosis regulatory

Zinc finger protein 598 inhibits cell survival by promoting UV-induced apoptosis.

Science.gov (United States)

Yang, Qiaohong; Gupta, Romi

2018-01-19

UV is one of the major causes of DNA damage induced apoptosis. However, cancer cells adopt alternative mechanisms to evade UV-induced apoptosis. To identify factors that protect cancer cells from UV-induced apoptosis, we performed a genome wide short-hairpin RNA (shRNA) screen, which identified Zinc finger protein 598 (ZNF598) as a key regulator of UV-induced apoptosis. Here, we show that UV irradiation transcriptionally upregulates ZNF598 expression. Additionally, ZNF598 knockdown in cancer cells inhibited UV-induced apoptosis. In our study, we observe that ELK1 mRNA level as well as phosphorylated ELK1 levels was up regulated upon UV irradiation, which was necessary for UV irradiation induced upregulation of ZNF598. Cells expressing ELK1 shRNA were also resistant to UV-induced apoptosis, and phenocopy ZNF598 knockdown. Upon further investigation, we found that ZNF598 knockdown inhibits UV-induced apoptotic gene expression, which matches with decrease in percentage of annexin V positive cell. Similarly, ectopic expression of ZNF598 promoted apoptotic gene expression and also increased annexin V positive cells. Collectively, these results demonstrate that ZNF598 is a UV irradiation regulated gene and its loss results in resistance to UV-induced apoptosis.

The effects of cysteamine on the radiation-induced apoptosis

International Nuclear Information System (INIS)

Choi, Young Min; Cho, Heung Lae; Park, Chang Gyo; Lee, Hyung Sik; Hur, Won Joo

2000-01-01

To investigate the pathways of radiation induced apoptosis and the effect of cysteamine (β-mercaptoethylamine), as a radioprotector, on it. HL-60 cells were assigned to control, irradiated, and cysteamine (1 mM, 10 mM) pretreated groups. Irradiation was given in a single fraction of 10 Gy (6 MV x-ray) and cysteamine was administered 1 hour before irradiation. The activities of caspase-8 were measured in control and irradiated group to evaiuate its relation to the radiation induced apoptosis. To evaluate the role of cysteamine in radiation induced apoptosis, the number of viable cells, the expression and activity or caspase-3, and the expression of poly (ADP-ribose) polymerase (PARP) were measured and compared after irradiating the HL cells with cysteamine pretreatment or not. The intracellular caspase-8 activity, known to be related to the death receptor induced apoptosis, was not affected by irradiation( p>0.05). The number of viable cells began to decrease from 6 hours after irradiation (p>0.05), but the number of viable cells in 1 mM cysteamine pretreated group was not decreased after irradiation and was similar to those in the control group. In caspase-3 analyses, known as apoptosis executioner, its expression was not different but its activity was increased by irradialion(p>0.05). However, this increase of activity was suppressed by the pretreatment of 1 mM cysteamine. The cleavage of PARP, thought to be resulted from caspase-3 activation, occurred, after irradiation, which was attenuated by the pretreatment of 1 mM cysteamine. These results show that radiation induced apoptotic process is somewhat different from death receptor induced one and the pretreatment of 1 mM cysteamine has a tendency to decrease the radiation-induced apoptosis in HL-60 cells

MicroRNAs regulate B-cell receptor signaling-induced apoptosis

NARCIS (Netherlands)

Kluiver, J. L.; Chen, C-Z

Apoptosis induced by B-cell receptor (BCR) signaling is critical for antigen-driven selection, a process critical to tolerance and immunity. Here, we examined the roles of microRNAs (miRNAs) in BCR signaling-induced apoptosis using the widely applied WEHI-231 model. Comparison of miRNA levels in

[Intragenic mitotic recombination induced by ultraviolet and gamma rays in radiosensitive mutants of Saccharomyces cerevisiae yeasts].

Science.gov (United States)

Zakharov, I A; Kasinova, G V; Koval'tsova, S V

1983-01-01

The effect of UV- and gamma-irradiation on the survival and intragenic mitotic recombination (gene conversion) of 5 radiosensitive mutants was studied in comparison with the wild type. The level of spontaneous conversion was similar for RAD, rad2 and rad15, mutations xrs2 and xrs4 increasing and rad54 significantly decreasing it. The frequency of conversion induced by UV-light was greater in rad2, rad15 and xrs2 mutants and lower in xrs4, as compared to RAD. Gamma-irradiation caused induction of gene conversion with an equal frequency in RAD, rad2, rad15. Xrs2 and xrs4 mutations slightly decreased gamma-induced conversion. In rad54 mutant, UV-and gamma-induced conversion was practically absent. In the wild type yeast, a diploid strain is more resistant than a haploid, whereas in rad54 a diploid strain has the same or an increased sensitivity, as compared to a haploid strain (the "inverse ploidy effect"). This effect and also the block of induced mitotic recombination caused by rad54 indicate the presence in the yeast Saccharomyces cerevisiae of repair pathways of UV- and gamma-induced damages acting in diploid cells and realised by recombination. The data obtained as a result of many years' investigation of genetic effects in radiosensitive mutants of yeast are summarised and considered.

The characteristics and mechanism of apoptosis induced by internal irradiation

International Nuclear Information System (INIS)

Hong Chengjiao; Zhang Junning; Zhu Shoupeng

2001-01-01

Apoptosis in tumor cells induced by radionuclides is likely the most effective way to cure cancer. In order to explore the possibility in clinic application, the characteristics and mechanism of apoptosis induced by internal irradiation were investigated. The apoptosis and expressions of bcl-2mRNA, bcl-2 and bax of K 562 cells following internal exposure with different accumulated absorbed doses of strontium-89 were studied. 6 h after irradiation, the characteristics of apoptosis and necrosis appeared in K 562 cells. The apoptosis and necrosis enhanced with the prolongation of internally contaminated time at 6 h, 9 h, 12 h, 24 h and 48 h. The expressions of bcl-2mRNA decreased at 12 h, most remarkably at 24 h. The expressions of bcl-2 decreased after irradiation whereas bax had no obvious changes. The results suggest that the apoptosis induced by internal exposure may be regulated by lower expressions of bcl-2mRNA and bcl-2, lower bcl-2/bax value

Expression of HSF2 decreases in mitosis to enable stress-inducible transcription and cell survival

Science.gov (United States)

Elsing, Alexandra N.; Aspelin, Camilla; Björk, Johanna K.; Bergman, Heidi A.; Himanen, Samu V.; Kallio, Marko J.; Roos-Mattjus, Pia

2014-01-01

Unless mitigated, external and physiological stresses are detrimental for cells, especially in mitosis, resulting in chromosomal missegregation, aneuploidy, or apoptosis. Heat shock proteins (Hsps) maintain protein homeostasis and promote cell survival. Hsps are transcriptionally regulated by heat shock factors (HSFs). Of these, HSF1 is the master regulator and HSF2 modulates Hsp expression by interacting with HSF1. Due to global inhibition of transcription in mitosis, including HSF1-mediated expression of Hsps, mitotic cells are highly vulnerable to stress. Here, we show that cells can counteract transcriptional silencing and protect themselves against proteotoxicity in mitosis. We found that the condensed chromatin of HSF2-deficient cells is accessible for HSF1 and RNA polymerase II, allowing stress-inducible Hsp expression. Consequently, HSF2-deficient cells exposed to acute stress display diminished mitotic errors and have a survival advantage. We also show that HSF2 expression declines during mitosis in several but not all human cell lines, which corresponds to the Hsp70 induction and protection against stress-induced mitotic abnormalities and apoptosis. PMID:25202032

Apoptosis-induced lymphopenia in sepsis and other severe injuries.

Science.gov (United States)

Girardot, Thibaut; Rimmelé, Thomas; Venet, Fabienne; Monneret, Guillaume

2017-02-01

Sepsis and other acute injuries such as severe trauma, extensive burns, or major surgeries, are usually followed by a period of marked immunosuppression. In particular, while lymphocytes play a pivotal role in immune response, their functions and numbers are profoundly altered after severe injuries. Apoptosis plays a central role in this process by affecting immune response at various levels. Indeed, apoptosis-induced lymphopenia duration and depth have been associated with higher risk of infection and mortality in various clinical settings. Therapies modulating apoptosis represent an interesting approach to restore immune competence after acute injury, although their use in clinical practice still presents several limitations. After briefly describing the apoptosis process in physiology and during severe injuries, we will explore the immunological consequences of injury-induced lymphocyte apoptosis, and describe associations with clinically relevant outcomes in patients. Therapeutic perspectives targeting apoptosis will also be discussed.

Angiotensin II protects primary rat hepatocytes against bile salt-induced apoptosis.

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Golnar Karimian

Full Text Available UNLABELLED: Angiotensin II (AT-II is a pro-fibrotic compound that acts via membrane-bound receptors (AT-1R/AT-2R and thereby activates hepatic stellate cells (HSCs. AT-II receptor blockers (ARBs are thus important candidates in the treatment of liver fibrosis. However, multiple case reports suggest that AT-1R blockers may induce hepatocyte injury. Therefore, we investigated the effect of AT-II and its receptor blockers on cytokine-, oxidative stress- and bile salt-induced cell death in hepatocytes. Primary rat hepatocytes were exposed to TNF-α/Actinomycin D, the ROS-generating agent menadione or the bile salts: glycochenodeoxycholic acid (GCDCA and tauro-lithocholic acid-3 sulfate (TLCS, to induce apoptosis. AT-II (100 nmol/L was added 10 minutes prior to the cell death-inducing agent. AT-1R antagonists (Sartans and the AT-2R antagonist PD123319 were used at 1 µmol/L. Apoptosis (caspase-3 activity, acridine orange staining and necrosis (Sytox green staining were quantified. Expression of CHOP (marker for ER stress and AT-II receptor mRNAs were quantified by Q-PCR. AT-II dose-dependently reduced GCDCA-induced apoptosis of hepatocytes (-50%, p<0.05 without inducing necrosis. In addition, AT-II reduced TLCS-induced apoptosis of hepatocytes (-50%, p<0.05. However, AT-II did not suppress TNF/Act-D and menadione-induced apoptosis. Only the AT-1R antagonists abolished the protective effect of AT-II against GCDCA-induced apoptosis. AT-II increased phosphorylation of ERK and a significant reversal of the protective effect of AT-II was observed when signaling kinases, including ERK, were inhibited. Moreover, AT-II prevented the GCDCA-induced expression of CHOP (the marker of the ER-mediated apoptosis. CONCLUSION: Angiotensin II protects hepatocytes from bile salt-induced apoptosis through a combined activation of PI3-kinase, MAPKs, PKC pathways and inhibition of bile salt-induced ER stress. Our results suggest a mechanism for the observed hepatocyte

Spironolactone induces apoptosis in human mononuclear cells. Association between apoptosis and cytokine suppression

DEFF Research Database (Denmark)

Mikkelsen, Martin; Sønder, S U; Nersting, J

2006-01-01

Spironolactone (SPIR) has been described to suppress accumulation of pro-inflammatory cytokines. Here, the suppression of TNF-alpha in lipopolysaccharide (LPS)-stimulated mononuclear cell cultures was confirmed. However, SPIR was also found to induce apoptosis, prompting the investigations...... of a possible association between the two effects: The apoptosis-inducing and the cytokine-suppressive effects of SPIR correlated with regard to the effective concentration range. Also, pre-incubation experiments demonstrated a temporal separation of the two effects of ... preceding apoptosis. An association between the two effects was also seen when testing several SPIR analogues. Contrary to TNF-alpha, the levels of IL-1beta increased in SPIR-treated cultures. However, the amount of IL-1beta in the supernatants depended upon the order of SPIR and LPS addition, as IL-1beta...

Increased p53 and decreased p21 accompany apoptosis induced by ultraviolet radiation in the nervous system of a crustacean

International Nuclear Information System (INIS)

Hollmann, Gabriela; Linden, Rafael; Giangrande, Angela; Allodi, Silvana

2016-01-01

Highlights: • The paper characterizes molecular pathways of cell responses to environmental doses of UV in brain tissue of a crab species. • The UV radiation changes levels of proteins which trigger apoptotic or cell cycle arrest pathways and also it changes neurotrophins which lead to apoptosis of neural cell in the central nervous system (CNS) of the crab Ucides cordatus. • The UVB wavelengths in the solar simulator damaged the DNA, either directly or indirectly, by increasing ROS, and induced the increase of p53 and AKT, which blocked p21 and increased the expression of activated caspase-3, triggering apoptosis. The signs of death increased the expression of neurotrophins (BDNF and GDNF), which continued to stimulate the apoptosis signaling mediated by caspase-3. • In the brain of the crab U. cordatus, p53/p21 relationship in response to UV radiation is different from that of most mammals. - Abstract: Ultraviolet (UV) radiation can produce biological damage, leading the cell to apoptosis by the p53 pathway. This study evaluated some molecular markers of the apoptosis pathway induced by UVA, UVB and UVA+ UVB (Solar Simulator, SIM) in environmental doses, during five consecutive days of exposure, in the brain of the crab Ucides cordatus. We evaluated the central nervous system (CNS) by immunoblotting the content of proteins p53, p21, phosphorylated AKT, BDNF, GDNF, activated caspase-3 (C3) and phosphohistone H3 (PH3); and by immunohistochemical tests of the cells labeled for PH3 and C3. After the fifth day of exposure, UVB radiation and SIM increased the protein content of p53, increasing the content of AKT and, somehow, blocking p21, increasing the content of activated caspase-3, which led the cells to apoptosis. The signs of death affected the increase in neurotrophins, such as BDNF and GDNF, stimulating the apoptotic cascade of events. Immunohistochemical assays and immunoblotting showed that apoptosis was present in the brains of all UV groups, while

Increased p53 and decreased p21 accompany apoptosis induced by ultraviolet radiation in the nervous system of a crustacean

Energy Technology Data Exchange (ETDEWEB)

Hollmann, Gabriela, E-mail: gabrielahollmann@biof.ufrj.br [Programa de Pós Graduação em Ciências Biológicas-Fisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro-UFRJ, Rio de Janeiro, RJ 21941-590 (Brazil); Linden, Rafael, E-mail: rlinden@biof.ufrj.br [Programa de Pós Graduação em Ciências Biológicas-Fisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro-UFRJ, Rio de Janeiro, RJ 21941-590 (Brazil); Giangrande, Angela, E-mail: angela.giangrande@igbmc.fr [Institut de Génétique et de Biologie Moléculaire et Cellulaire-IGBMC, INSERM, Strasbourg (France); Allodi, Silvana, E-mail: sallodi@biof.ufrj.br [Programa de Pós Graduação em Ciências Biológicas-Fisiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro-UFRJ, Rio de Janeiro, RJ 21941-590 (Brazil)

2016-04-15

Highlights: • The paper characterizes molecular pathways of cell responses to environmental doses of UV in brain tissue of a crab species. • The UV radiation changes levels of proteins which trigger apoptotic or cell cycle arrest pathways and also it changes neurotrophins which lead to apoptosis of neural cell in the central nervous system (CNS) of the crab Ucides cordatus. • The UVB wavelengths in the solar simulator damaged the DNA, either directly or indirectly, by increasing ROS, and induced the increase of p53 and AKT, which blocked p21 and increased the expression of activated caspase-3, triggering apoptosis. The signs of death increased the expression of neurotrophins (BDNF and GDNF), which continued to stimulate the apoptosis signaling mediated by caspase-3. • In the brain of the crab U. cordatus, p53/p21 relationship in response to UV radiation is different from that of most mammals. - Abstract: Ultraviolet (UV) radiation can produce biological damage, leading the cell to apoptosis by the p53 pathway. This study evaluated some molecular markers of the apoptosis pathway induced by UVA, UVB and UVA+ UVB (Solar Simulator, SIM) in environmental doses, during five consecutive days of exposure, in the brain of the crab Ucides cordatus. We evaluated the central nervous system (CNS) by immunoblotting the content of proteins p53, p21, phosphorylated AKT, BDNF, GDNF, activated caspase-3 (C3) and phosphohistone H3 (PH3); and by immunohistochemical tests of the cells labeled for PH3 and C3. After the fifth day of exposure, UVB radiation and SIM increased the protein content of p53, increasing the content of AKT and, somehow, blocking p21, increasing the content of activated caspase-3, which led the cells to apoptosis. The signs of death affected the increase in neurotrophins, such as BDNF and GDNF, stimulating the apoptotic cascade of events. Immunohistochemical assays and immunoblotting showed that apoptosis was present in the brains of all UV groups, while

Bisphenol A induces spermatocyte apoptosis in rare minnow Gobiocypris rarus

International Nuclear Information System (INIS)

Zhang, Yingying; Cheng, Mengqian; Wu, Lang; Zhang, Guo; Wang, Zaizhao

2016-01-01

Highlights: • Adult male G. rarus were exposed to 225 μg/L BPA for 7, 21 and 63 days. • BPA could induce spermatocyte apoptosis in rare minnow testis. • The mitochondrial apoptotic pathway participated in the germ cell apoptosis. • The spermatocyte apoptosis was likely initiated by BPA induced meiosis arrest. - Abstract: Bisphenol A (BPA) is an endocrine disruptor, and could induce germ cells apoptosis in the testis of mammals. But whether it could affect fish in the same mechanism has not’ been studied till now. In the present study, to investigate the influence of BPA on testis germ cells in fish, adult male rare minnow Gobiocypris rarus were exposed to 225 μg L"−"1 (0.99 μM) BPA for 1, 3 and 9 weeks. Through TdT-mediated dUTP nick end labeling (TUNEL) and transmission electron microscope (TEM) analysis, we found that the amount of apoptotic spermatocytes significantly increased in a time dependent manner following BPA exposure. Western Blot results showed that the ratio of Bcl2/Bax, the important apoptosis regulators in intrinsic mitochondrial apoptotic pathway, was significantly decreased. qPCR showed that mRNA expression of several genes in mitochondrial apoptotic pathway including bcl2, bax, casp9, cytc and mcl1b were significantly changed following BPA exposure. In addition, mRNA expression of meiosis regulation genes (kpna7 and wee2), and genes involved in both apoptosis and meiosis (birc5, ccna1, and gsa1a) were also affected by BPA. Taken together, the present study demonstrated that BPA could induce spermatocytes apoptosis in rare minnow testis, and the apoptosis was probably under regulation of intrinsic mitochondrial apoptotic pathway. Moreover, the spermatocyte apoptosis was likely initiated by BPA induced meiosis arrest.

Bisphenol A induces spermatocyte apoptosis in rare minnow Gobiocypris rarus

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yingying; Cheng, Mengqian; Wu, Lang; Zhang, Guo; Wang, Zaizhao, E-mail: zzwang@nwsuaf.edu.cn

2016-10-15

Highlights: • Adult male G. rarus were exposed to 225 μg/L BPA for 7, 21 and 63 days. • BPA could induce spermatocyte apoptosis in rare minnow testis. • The mitochondrial apoptotic pathway participated in the germ cell apoptosis. • The spermatocyte apoptosis was likely initiated by BPA induced meiosis arrest. - Abstract: Bisphenol A (BPA) is an endocrine disruptor, and could induce germ cells apoptosis in the testis of mammals. But whether it could affect fish in the same mechanism has not’ been studied till now. In the present study, to investigate the influence of BPA on testis germ cells in fish, adult male rare minnow Gobiocypris rarus were exposed to 225 μg L{sup −1} (0.99 μM) BPA for 1, 3 and 9 weeks. Through TdT-mediated dUTP nick end labeling (TUNEL) and transmission electron microscope (TEM) analysis, we found that the amount of apoptotic spermatocytes significantly increased in a time dependent manner following BPA exposure. Western Blot results showed that the ratio of Bcl2/Bax, the important apoptosis regulators in intrinsic mitochondrial apoptotic pathway, was significantly decreased. qPCR showed that mRNA expression of several genes in mitochondrial apoptotic pathway including bcl2, bax, casp9, cytc and mcl1b were significantly changed following BPA exposure. In addition, mRNA expression of meiosis regulation genes (kpna7 and wee2), and genes involved in both apoptosis and meiosis (birc5, ccna1, and gsa1a) were also affected by BPA. Taken together, the present study demonstrated that BPA could induce spermatocytes apoptosis in rare minnow testis, and the apoptosis was probably under regulation of intrinsic mitochondrial apoptotic pathway. Moreover, the spermatocyte apoptosis was likely initiated by BPA induced meiosis arrest.

A nontranscriptional role for Oct4 in the regulation of mitotic entry

Science.gov (United States)

Zhao, Rui; Deibler, Richard W.; Lerou, Paul H.; Ballabeni, Andrea; Heffner, Garrett C.; Cahan, Patrick; Unternaehrer, Juli J.; Kirschner, Marc W.; Daley, George Q.

2014-01-01

Rapid progression through the cell cycle and a very short G1 phase are defining characteristics of embryonic stem cells. This distinct cell cycle is driven by a positive feedback loop involving Rb inactivation and reduced oscillations of cyclins and cyclin-dependent kinase (Cdk) activity. In this setting, we inquired how ES cells avoid the potentially deleterious consequences of premature mitotic entry. We found that the pluripotency transcription factor Oct4 (octamer-binding transcription factor 4) plays an unappreciated role in the ES cell cycle by forming a complex with cyclin–Cdk1 and inhibiting Cdk1 activation. Ectopic expression of Oct4 or a mutant lacking transcriptional activity recapitulated delayed mitotic entry in HeLa cells. Reduction of Oct4 levels in ES cells accelerated G2 progression, which led to increased chromosomal missegregation and apoptosis. Our data demonstrate an unexpected nontranscriptional function of Oct4 in the regulation of mitotic entry. PMID:25324523

Bim is a crucial regulator of apoptosis induced by Mycobacterium tuberculosis

Science.gov (United States)

Aguiló, N; Uranga, S; Marinova, D; Martín, C; Pardo, J

2014-01-01

Mycobacterium tuberculosis, the causative agent of tuberculosis, induces apoptosis in infected macrophages in vitro and in vivo. However, the molecular mechanism controlling this process is not known. In order to study the involvement of the mitochondrial apoptotic pathway in M. tuberculosis-induced apoptosis, we analysed cell death in M. tuberculosis-infected embryonic fibroblasts (MEFs) derived from different knockout mice for genes involved in this route. We found that apoptosis induced by M. tuberculosis is abrogated in the absence of Bak and Bax, caspase 9 or the executioner caspases 3 and 7. Notably, we show that MEF deficient in the BH3-only BCL-2-interacting mediator of cell death (Bim) protein were also resistant to this process. The relevance of these results has been confirmed in the mouse macrophage cell line J774, where cell transfection with siRNA targeting Bim impaired apoptosis induced by virulent mycobacteria. Notably, only infection with a virulent strain, but not with attenuated ESX-1-defective strains, such as Bacillus Calmette-Guerin and live-attenuated M. tuberculosis vaccine strain MTBVAC, induced Bim upregulation and apoptosis, probably implicating virulence factor early secreted antigenic target 6-kDa protein in this process. Our results suggest that Bim upregulation and apoptosis is mediated by the p38MAPK-dependent pathway. Our findings show that Bim is a master regulator of apoptosis induced by M. tuberculosis. PMID:25032866

Lysophosphatidic acid rescues bone mesenchymal stem cells from hydrogen peroxide-induced apoptosis.

Science.gov (United States)

Wang, Xian-Yun; Fan, Xue-Song; Cai, Lin; Liu, Si; Cong, Xiang-Feng; Chen, Xi

2015-03-01

The increase of reactive oxygen species in infracted heart significantly reduces the survival of donor mesenchymal stem cells, thereby attenuating the therapeutic efficacy for myocardial infarction. In our previous study, we demonstrated that lysophosphatidic acid (LPA) protects bone marrow-derived mesenchymal stem cells (BMSCs) against hypoxia and serum deprivation-induced apoptosis. However, whether LPA protects BMSCs from H2O2-induced apoptosis was not examined. In this study, we report that H2O2 induces rat BMSC apoptosis whereas LPA pre-treatment effectively protects BMSCs from H2O2-induced apoptosis. LPA protection of BMSC from the induced apoptosis is mediated mostly through LPA3 receptor. Furthermore, we found that membrane G protein Gi2 and Gi3 are involved in LPA-elicited anti-apoptotic effects through activation of ERK1/2- and PI3 K-pathways. Additionally, H2O2 increases levels of type II of light chain 3B (LC3B II), an autophagy marker, and H2O2-induced autophagy thus protected BMSCs from apoptosis. LPA further increases the expression of LC3B II in the presence of H2O2. In contrast, autophagy flux inhibitor bafilomycin A1 has no effect on LPA's protection of BMSC from H2O2-induced apoptosis. Taken together, our data suggest that LPA rescues H2O2-induced apoptosis mainly by interacting with Gi-coupled LPA3, resulting activation of the ERK1/2- and PI3 K/AKT-pathways and inhibition caspase-3 cleavage, and LPA protection of BMSCs against the apoptosis is independent of it induced autophagy.

Dioscin induces caspase-independent apoptosis through activation of apoptosis-inducing factor in breast cancer cells.

Science.gov (United States)

Kim, Eun-Ae; Jang, Ji-Hoon; Lee, Yun-Han; Sung, Eon-Gi; Song, In-Hwan; Kim, Joo-Young; Kim, Suji; Sohn, Ho-Yong; Lee, Tae-Jin

2014-07-01

Dioscin, a saponin extracted from the roots of Polygonatum zanlanscianense, shows several bioactivities such as antitumor, antifungal, and antiviral properties. Although, dioscin is already known to induce cell death in variety cancer cells, the molecular basis for dioscin-induced cell death was not definitely known in cancer cells. In this study, we found that dioscin treatment induced cell death in dose-dependent manner in breast cancer cells such as MDA-MB-231, MDA-MB-453, and T47D cells. Dioscin decreased expressions of Bcl-2 and cIAP-1 proteins, which were down-regulated at the transcriptional level. Conversely, Mcl-1 protein level was down-regulated by facilitating ubiquitin/proteasome-mediated Mcl-1 degradation in dioscin-treated cells. Pretreatment with z-VAD fails to attenuate dioscin-induced cell death as well as caspase-mediated events such as cleavages of procaspase-3 and PARP. In addition, dioscin treatment increased the population of annexin V positive cells and induced DNA fragmentation in a dose-dependent manner in MDA-MB-231 cells. Furthermore, apoptosis inducing factor (AIF) was released from the mitochondria and translocated to the nucleus. Suppression in AIF expression by siRNA reduced dioscin-induced apoptosis in MDA-MB-231 cells. Taken together, our results demonstrate that dioscin-induced cell death was mediated via AIF-facilitating caspase-independent pathway as well as down-regulating anti-apoptotic proteins such as Bcl-2, cIAP-1, and Mcl-1 in breast cancer cells.

Fisetin induces apoptosis through mitochondrial apoptosis pathway in human uveal melanoma cells.

Science.gov (United States)

Wang, Kai; Hu, Dan-Ning; Lin, Hui-Wen; Yang, Wei-En; Hsieh, Yi-Hsien; Chien, Hsiang-Wen; Yang, Shun-Fa

2018-05-01

Fisetin, a diatery flavonoid, been reported that possess anticancer effects in various cancers. The purpose of the study was to investigate the antitumor effects of fisetin in cultured uveal melanoma cell lines and compared with normal retinal pigment epithelial (RPE) cells. MTT assay was used for evaluating cytotoxic effects of fisetin. Flow cytometry study was used for the determination of apoptosis. JC-1 fluorescent reader was used to determine mitochondrial transmembrane potential changes. The results shown that fisetin dose-dependently decreased the cell viability of uveal melanoma cells but not influenced the cell viability of RPE cells. Apoptosis of uveal melanoma cells was induced by fisetin efficiently. Fisetin inhibited antiapoptotic Bcl-2 family proteins and damaged the mitochondrial transmembrane potential. The levels of proapoptotic Bcl-2 proteins, cytochrome c, and various caspase activities were increased by fisetin. In conclusion, fisetin induces apoptosis of uveal melanoma cells selectively and may be a promising agent to be explored for the treatment of uveal melanoma. © 2018 Wiley Periodicals, Inc.

Induced mitotic gynogenesis in common carp (Cyprinus carpio L.), optimizing irradiation dose of X- and gamma-ray

International Nuclear Information System (INIS)

Yousefian, M.; Amirinia, C.; Bercsenyi, M.; Horvath, L.

1997-01-01

Mitotic gynogenesis was induced in common carp, Cyprinus carpio L., in hatchery and laboratory conditions, using 60Co gamma-ray and X-ray for inactivation of sperm DNA and a subsequent heat shock for inducing endomitosis. The parameter examined was the dose of irradiation in the range of 70-140 Krad. Carp spermatozoa irradiated by 70-100 Krad doses showed higher motility and fertilization ability than the ones irradiated by 110-140 Krad. Sperm treated with doses of 70-90 Krad showed the same fertility rate, but lower survival rate at embryo stage compared with 100 Krad. The shock temperature and duration applied in these experiments for restoration of diploidy level were 40 degrees C plus/minus 0.1 and 2 min., respectively. The highest frequency of mitotic gynogenetic larvae was achieved by 100 Krad 60Co gamma ray at 34 min. after fertilization, - up to 12.2 percent (at 23 degrees C incubating temperature)

Docetaxel-induced prostate cancer cell death involves concomitant activation of caspase and lysosomal pathways and is attenuated by LEDGF/p75

Directory of Open Access Journals (Sweden)

Leoh Lai

2009-08-01

Full Text Available Abstract Background Hormone-refractory prostate cancer (HRPC is characterized by poor response to chemotherapy and high mortality, particularly among African American men when compared to other racial/ethnic groups. It is generally accepted that docetaxel, the standard of care for chemotherapy of HRPC, primarily exerts tumor cell death by inducing mitotic catastrophe and caspase-dependent apoptosis following inhibition of microtubule depolymerization. However, there is a gap in our knowledge of mechanistic events underlying docetaxel-induced caspase-independent cell death, and the genes that antagonize this process. This knowledge is important for circumventing HRPC chemoresistance and reducing disparities in prostate cancer mortality. Results We investigated mechanistic events associated with docetaxel-induced death in HRPC cell lines using various approaches that distinguish caspase-dependent from caspase-independent cell death. Docetaxel induced both mitotic catastrophe and caspase-dependent apoptosis at various concentrations. However, caspase activity was not essential for docetaxel-induced cytotoxicity since cell death associated with lysosomal membrane permeabilization still occurred in the presence of caspase inhibitors. Partial inhibition of docetaxel-induced cytotoxicity was observed after inhibition of cathepsin B, but not inhibition of cathepsins D and L, suggesting that docetaxel induces caspase-independent, lysosomal cell death. Simultaneous inhibition of caspases and cathepsin B dramatically reduced docetaxel-induced cell death. Ectopic expression of lens epithelium-derived growth factor p75 (LEDGF/p75, a stress survival autoantigen and transcription co-activator, attenuated docetaxel-induced lysosomal destabilization and cell death. Interestingly, LEDGF/p75 overexpression did not protect cells against DTX-induced mitotic catastrophe, and against apoptosis induced by tumor necrosis factor related apoptosis inducing ligand (TRAIL

Dose-effect relationship of apoptosis induced by fission-neutron in murine thymocytes

International Nuclear Information System (INIS)

Yuan Bin; Li Liang; Xue Wencheng; Sun Jianmin; Wang Baoqin

2000-01-01

Objective: To investigate the effectiveness of high LET fission-neutron to induce apoptosis in murine thymocytes and to compare it with that of low LET 60 Co γ-ray. Methods: Apoptosis induction was studied qualitatively by light and transmission electron microscopy and DNA gel electrophoresis,also quantitatively by flow cytometry(FCM) and diphenylamine (DPA)methods. Results: DNA ladders of murine thymocytes were detectable, the typical apoptosis of thymocytes could be observed morphologically by means of light and electron microscopy at 6 h after fission-neutron irradiation with doses ranging from 0.5 to 5.0 Gy, meanwhile the percentages of apoptosis increased with increasing doses. After exposure to γ-rays with doses ranging from 1.0 to 30 Gy, the experimental results were similar to those from neutron radiation. The incidence of apoptosis peaked at about 20 Gy, the percentages did not increase further when doses increased. Conclusion: Apoptosis of murine thymocytes can be induced when mice are exposed to either fission-neutron (0.5-5.0 Gy) or to γ-ray (1-30 Gy). Although the relationship between apoptosis and radiation doses is similar, the percentage of apoptosis induced by neutron irradiation is higher than that induced by γ-irradiation. The RBE values of fission-neutron for inducing apoptosis murine thymocytes are 2.09 (by FCM method) and 2.37 (by DPA method), respectively. These results also suggest that fission-neutron-induced murine immune tissue is more severe than that induced by γ-rays at several hours post-irradiation and this might be the basis for heavy damage to immune tissues induced by fission-neutron-irradiation in later period

Functional role of CCCTC binding factor (CTCF) in stress-induced apoptosis

International Nuclear Information System (INIS)

Li Tie; Lu Luo

2007-01-01

CTCF, a nuclear transcriptional factor, is a multifunctional protein and involves regulation of growth factor- and cytokine-induced cell proliferation/differentiation. In the present study, we investigated the role of CTCF in protecting stress-induced apoptosis in various human cell types. We found that UV irradiation and hyper-osmotic stress induced human corneal epithelial (HCE) and hematopoietic myeloid cell apoptosis detected by significantly increased caspase 3 activity and decreased cell viability. The stress-induced apoptotic response in these cells requires down-regulation of CTCF at both mRNA and protein levels, suggesting that CTCF may play an important role in downstream events of stress-induced signaling pathways. Inhibition of NFκB activity prevented stress-induced down-regulation of CTCF and increased cell viability against stress-induced apoptosis. The anti-apoptotic effect of CTCF was further studied by manipulating CTCF activities in HCE and hematopoietic cells. Transient transfection of cDNAs encoding full-length human CTCF markedly suppressed stress-induced apoptosis in these cells. In contrast, knocking down of CTCF mRNA using siRNA specific to CTCF significantly promoted stress-induced apoptosis. Thus, our results reveal that CTCF is a down stream target of stress-induced signaling cascades and it plays a significant anti-apoptotic role in regulation of stress-induced cellular responses in HCE and hematopoietic myeloid cells

Ursodeoxycholic Acid Induces Death Receptor-mediated Apoptosis in Prostate Cancer Cells

Science.gov (United States)

Lee, Won Sup; Jung, Ji Hyun; Panchanathan, Radha; Yun, Jeong Won; Kim, Dong Hoon; Kim, Hye Jung; Kim, Gon Sup; Ryu, Chung Ho; Shin, Sung Chul; Hong, Soon Chan; Choi, Yung Hyun; Jung, Jin-Myung

2017-01-01

Background Bile acids have anti-cancer properties in a certain types of cancers. We determined anticancer activity and its underlying molecular mechanism of ursodeoxycholic acid (UDCA) in human DU145 prostate cancer cells. Methods Cell viability was measured with an MTT assay. UDCA-induced apoptosis was determined with flow cytometric analysis. The expression levels of apoptosis-related signaling proteins were examined with Western blotting. Results UDCA treatment significantly inhibited cell growth of DU145 in a dose-dependent manner. It induced cellular shrinkage and cytoplasmic blebs and accumulated the cells with sub-G1 DNA contents. Moreover, UDCA activated caspase 8, suggesting that UDCA-induced apoptosis is associated with extrinsic pathway. Consistent to this finding, UDCA increased the expressions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, death receptor 4 (DR4) and death receptor 5 (DR5), and TRAIL augmented the UDCA-induced cell death in DU145 cells. In addition, UDCA also increased the expressions of Bax and cytochrome c and decreased the expression of Bcl-xL in DU145 cells. This finding suggests that UDCA-induced apoptosis may be involved in intrinsic pathway. Conclusions UDCA induces apoptosis via extrinsic pathway as well as intrinsic pathway in DU145 prostate cancer cells. UDCA may be a promising anti-cancer agent against prostate cancer. PMID:28382282

Heat Shock Protein 70 Neutralizes Apoptosis-Inducing Factor

Directory of Open Access Journals (Sweden)

Guido Kroemer

2001-01-01

Full Text Available Programmed cell death (apoptosis is the physiological process responsible for the demise of superfluous, aged, damaged, mutated, and ectopic cells. Its normal function is essential both for embryonic development and for maintenance of adult tissue homeostasis. Deficient apoptosis participates in cancerogenesis, whereas excessive apoptosis leads to unwarranted cell loss accounting for disparate diseases including neurodegeneration and AIDS. One critical step in the process of apoptosis consists in the permeabilization of mitochondrial membranes, leading to the release of proteins which normally are secluded behind the outer mitochondrial membrane[1]. For example, cytochrome c, which is normally confined to the mitochondrial intermembrane space, is liberated from mitochondria and interacts with a cytosolic protein, Apaf-1, causing its oligomerization and constitution of the so-called apoptosome, a protein complex which activates a specific class of cysteine proteases, the caspases[2]. Another example concerns the so-called apoptosis-inducing factor (AIF, another mitochondrial intermembrane protein which can translocate to the nucleus where it induces chromatin condensation and DNA fragmentation[3].

Effect of precipitation route on the properties of antimony trioxide

International Nuclear Information System (INIS)

Abdullah, Abdul Halim; Noor, Nor Hayati Mohd; Ramli, Irmawati; Hashim, Mansor

2008-01-01

Antimony trioxide was prepared, using antimony potassium tartarate as starting material, via forward and reverse precipitation technique. The characteristics of the resulting antimony oxides were determined by BET surface area method, differential thermogravimetry analysis (DTG), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and SEM. The DTG curves for all uncalcined samples showed only a single endothermic peak which indicated that the sample is antimony trioxide. Unlike forward precipitation technique which resulted in a single antimony trioxide phase which is senarmontite, reverse precipitation technique produced antimony trioxide with both senarmontite and valentinite phase. Upon calcinations at 723 K, a small amount of Sb 2 O 4 with cervantite phase was formed at the expense of Sb 2 O 3 senarmontite phase as detected from the XRD pattern and infrared spectrum of RSb. The effect of preparation route on the properties of the antimony trioxide produced was clearly demonstrated

Bcl-2 prevents loss of mitochondria in CCCP-induced apoptosis

International Nuclear Information System (INIS)

Graaf, Aniek O. de; Heuvel, Lambert P. van den; Dijkman, Henry B.P.M.; Abreu, Ronney A. de; Birkenkamp, Kim U.; Witte, Theo de; Reijden, Bert A. van der; Smeitink, Jan A.M.; Jansen, Joop H.

2004-01-01

Bcl-2 family proteins regulate apoptosis at the level of mitochondria. To examine the mechanism of Bcl-2 function, we investigated the effects of the protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) on two hematopoietic cell lines and Bcl-2 overexpressing transfectants. CCCP directly interferes with mitochondrial function and induces apoptosis. We show that Bcl-2 inhibits apoptosis and that the antiapoptotic effect of Bcl-2 takes place upstream of caspase activation and nuclear changes associated with apoptosis, since these were markedly inhibited in cells overexpressing Bcl-2. Bcl-2 does not prevent the decrease in mitochondrial membrane potential nor the alterations in cellular ATP content induced by CCCP in FL5.12 and Jurkat cells. A higher number of mitochondria was observed in untreated Bcl-2 transfected cells compared to parental cells, as shown by electron microscopy. Exposure to CCCP induced a dramatic decrease in the number of mitochondria and severely disrupted mitochondrial ultrastructure, with apparent swelling and loss of cristae in parental cells. Bcl-2 clearly diminished the disruption of mitochondrial structure and preserved a higher number of mitochondria. These data suggest that CCCP induces apoptosis by structural disruption of mitochondria and that Bcl-2 prevents apoptosis and mitochondrial degeneration by preserving mitochondrial integrity

Bcl-2 prevents loss of mitochondria in CCCP-induced apoptosis.

Science.gov (United States)

de Graaf, Aniek O; van den Heuvel, Lambert P; Dijkman, Henry B P M; de Abreu, Ronney A; Birkenkamp, Kim U; de Witte, Theo; van der Reijden, Bert A; Smeitink, Jan A M; Jansen, Joop H

2004-10-01

Bcl-2 family proteins regulate apoptosis at the level of mitochondria. To examine the mechanism of Bcl-2 function, we investigated the effects of the protonophore carbonyl cyanide m-chlorophenyl hydrazone (CCCP) on two hematopoietic cell lines and Bcl-2 overexpressing transfectants. CCCP directly interferes with mitochondrial function and induces apoptosis. We show that Bcl-2 inhibits apoptosis and that the antiapoptotic effect of Bcl-2 takes place upstream of caspase activation and nuclear changes associated with apoptosis, since these were markedly inhibited in cells overexpressing Bcl-2. Bcl-2 does not prevent the decrease in mitochondrial membrane potential nor the alterations in cellular ATP content induced by CCCP in FL5.12 and Jurkat cells. A higher number of mitochondria was observed in untreated Bcl-2 transfected cells compared to parental cells, as shown by electron microscopy. Exposure to CCCP induced a dramatic decrease in the number of mitochondria and severely disrupted mitochondrial ultrastructure, with apparent swelling and loss of cristae in parental cells. Bcl-2 clearly diminished the disruption of mitochondrial structure and preserved a higher number of mitochondria. These data suggest that CCCP induces apoptosis by structural disruption of mitochondria and that Bcl-2 prevents apoptosis and mitochondrial degeneration by preserving mitochondrial integrity.

Effect of bFGF on radiation-induced apoptosis of vascular endothelial cells

International Nuclear Information System (INIS)

Gu Qingyang; Wang Dewen; Li Yuejuan; Peng Ruiyun; Dong Bo; Wang Zhaohai; Liu Jie; Deng Hua; Jiang Tao

2003-01-01

Objective: To study the effect of bFGF on radiation-induced apoptosis vascular endothelial cells. Methods: A cell line PAE (porcine aortic endothelial cells) and primary cultured HUVEC (human umbilical vein endothelial cells) were irradiated with 60 Co γ-rays to establish cell apoptosis models. Flow cytometry with annexin-V-FITC + PI labeling was used to evaluate cell apoptosis. Different amounts of bFGF were used to study their effects on radiation-induced endothelial cell apoptosis. Results and Conclusions: It is found that bFGF could inhibit radiation-induced endothelial cell apoptosis in a considerable degree

Neem oil limonoids induces p53-independent apoptosis and autophagy.

Science.gov (United States)

Srivastava, Pragya; Yadav, Neelu; Lella, Ravi; Schneider, Andrea; Jones, Anthony; Marlowe, Timothy; Lovett, Gabrielle; O'Loughlin, Kieran; Minderman, Hans; Gogada, Raghu; Chandra, Dhyan

2012-11-01

Azadirachta indica, commonly known as neem, has a wide range of medicinal properties. Neem extracts and its purified products have been examined for induction of apoptosis in multiple cancer cell types; however, its underlying mechanisms remain undefined. We show that neem oil (i.e., neem), which contains majority of neem limonoids including azadirachtin, induced apoptotic and autophagic cell death. Gene silencing demonstrated that caspase cascade was initiated by the activation of caspase-9, whereas caspase-8 was also activated late during neem-induced apoptosis. Pretreatment of cancer cells with pan caspase inhibitor, z-VAD inhibited activities of both initiator caspases (e.g., caspase-8 and -9) and executioner caspase-3. Neem induced the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria, suggesting the involvement of both caspase-dependent and AIF-mediated apoptosis. p21 deficiency caused an increase in caspase activities at lower doses of neem, whereas p53 deficiency did not modulate neem-induced caspase activation. Additionally, neem treatment resulted in the accumulation of LC3-II in cancer cells, suggesting the involvement of autophagy in neem-induced cancer cell death. Low doses of autophagy inhibitors (i.e., 3-methyladenine and LY294002) did not prevent accumulation of neem-induced LC3-II in cancer cells. Silencing of ATG5 or Beclin-1 further enhanced neem-induced cell death. Phosphoinositide 3-kinase (PI3K) or autophagy inhibitors increased neem-induced caspase-3 activation and inhibition of caspases enhanced neem-induced autophagy. Together, for the first time, we demonstrate that neem induces caspase-dependent and AIF-mediated apoptosis, and autophagy in cancer cells.

Neem oil limonoids induces p53-independent apoptosis and autophagy

Science.gov (United States)

Chandra, Dhyan

2012-01-01

Azadirachta indica, commonly known as neem, has a wide range of medicinal properties. Neem extracts and its purified products have been examined for induction of apoptosis in multiple cancer cell types; however, its underlying mechanisms remain undefined. We show that neem oil (i.e., neem), which contains majority of neem limonoids including azadirachtin, induced apoptotic and autophagic cell death. Gene silencing demonstrated that caspase cascade was initiated by the activation of caspase-9, whereas caspase-8 was also activated late during neem-induced apoptosis. Pretreatment of cancer cells with pan caspase inhibitor, z-VAD inhibited activities of both initiator caspases (e.g., caspase-8 and -9) and executioner caspase-3. Neem induced the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria, suggesting the involvement of both caspase-dependent and AIF-mediated apoptosis. p21 deficiency caused an increase in caspase activities at lower doses of neem, whereas p53 deficiency did not modulate neem-induced caspase activation. Additionally, neem treatment resulted in the accumulation of LC3-II in cancer cells, suggesting the involvement of autophagy in neem-induced cancer cell death. Low doses of autophagy inhibitors (i.e., 3-methyladenine and LY294002) did not prevent accumulation of neem-induced LC3-II in cancer cells. Silencing of ATG5 or Beclin-1 further enhanced neem-induced cell death. Phosphoinositide 3-kinase (PI3K) or autophagy inhibitors increased neem-induced caspase-3 activation and inhibition of caspases enhanced neem-induced autophagy. Together, for the first time, we demonstrate that neem induces caspase-dependent and AIF-mediated apoptosis, and autophagy in cancer cells. PMID:22915764

Noxa/Mcl-1 Balance Regulates Susceptibility of Cells to Camptothecin-Induced Apoptosis

Directory of Open Access Journals (Sweden)

Yide Mei

2007-10-01

Full Text Available Although camptothecin (CPT has been reported to induce apoptosis in various cancer cells, the molecular details of this regulation remain largely unknown. In this study, we demonstrate that 131-113-only protein Noxa is upregulated during CPT-induced apoptosis, which is independent of p53. In addition, we show that phosphatidylinositol 3-kinase (PI3K/Akt signaling pathway is responsible for Noxa's induction. Luciferase assay, cAMP response element binding protein (CREB knockdown experiments further demonstrate that CREB is involved in the transcriptional upregulation of Noxa. Moreover, blocking Noxa expression using specific small interfering ribonucleic acid (siRNA significantly reduces the apoptosis in response to CPT, indicating that Noxa is an essential mediator for CPT-induced apoptosis. Interestingly, antiapoptotic Mcl-1 was also upregulated through PI3K/Akt signaling pathway upon CPT treatment. Using immunoprecipitation assay, Noxa was found to interact with Mcl-1 in the presence or absence of CPT. Knockdown of Mcl-1 expression by short hairpin ribonucleic acid (shRNA was shown to potentiate CPT-induced apoptosis. Consistently, ectopic overexpression of Mcl-1 rescued cells from apoptosis induced by CPT. Cells coexpressing Noxa, Mcl-1 at different ratio correlates well with the extent of apoptosis, suggesting that the balance between Noxa, Mcl-1 may determine the susceptibility of HeLa cells to CPT-induced apoptosis.

Hypoxia-induced p53 modulates both apoptosis and radiosensitivity via AKT

NARCIS (Netherlands)

Leszczynska, K.B.; Foskolou, I.P.; Abraham, A.G.; Anbalagan, S.; Tellier, C.; Haider, S.; Span, P.N.; O'Neill, E.E.; Buffa, F.M.; Hammond, E.M.

2015-01-01

Restoration of hypoxia-induced apoptosis in tumors harboring p53 mutations has been proposed as a potential therapeutic strategy; however, the transcriptional targets that mediate hypoxia-induced p53-dependent apoptosis remain elusive. Here, we demonstrated that hypoxia-induced p53-dependent

Andrographolide induces apoptotic and non-apoptotic death and enhances tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in gastric cancer cells

OpenAIRE

Lim, Sung-Chul; Jeon, Ho Jong; Kee, Keun Hong; Lee, Mi Ja; Hong, Ran; Han, Song Iy

2017-01-01

Andrographolide, a natural compound isolated from Andrographis paniculata, has been reported to possess antitumor activity. In the present study, the effect of andrographolide in human gastric cancer (GC) cells was investigated. Andrographolide induced cell death with apoptotic and non-apoptotic features. At a low concentration, andrographolide potentiated apoptosis and reduction of clonogenicity triggered by recombinant human tumor necrosis factor-related apoptosis-inducing ligand (rhTRAIL)....

The role of cPLA2 in Methylglyoxal-induced cell apoptosis of HUVECs

International Nuclear Information System (INIS)

Yuan, Jie; Zhu, Chao; Hong, Yali; Sun, Zongxing; Fang, Xianjun; Wu, Biao; Li, Shengnan

2017-01-01

Methylglyoxal (MGO), a highly reactive dicarbonyl compound, is mainly formed as a byproduct of glycolysis. Elevated MGO level is known to induce apoptosis of vascular endothelial cells, which is implicated with progression of atherosclerosis and diabetic complications. However, the underlying mechanisms have not been exhaustively investigated yet. Here, we further characterized the mechanisms how MGO induced apoptosis in human umbilical vein endothelial cells (HUVECs). Our data revealed that cytosolic phospholipase A2 (cPLA2) played an important role in MGO-induced cell apoptosis. It was found that MGO could increase both the activity and expression of cPLA2. Inhibition of cPLA2 by Pyrrophenone (PYR) or siRNA significantly attenuated the MGO-induced apoptosis. Additionally, MGO time-dependently decreased the phosphorylation of nuclear factor κB (NF-κB). Pretreatment of the cells with NF-κB inhibitor, BAY11-7082, further increased MGO-induced apoptosis of HUVECs, indicating that NF-κB played a survival role in this MGO-induced apoptosis. Furthermore, in the presence of si-cPLA2 or PYR, MGO no longer decreased NF-κB phosphorylation. Beyond that, the antioxidant N-acetyl cysteine (NAC) could reverse the changes of both cPLA2 and NF-κB caused by MGO. p38, the upstream of cPLA2, was also significantly phosphorylated by MGO. However, p38 inhibitor failed to reverse the apoptosis induced by MGO. This study gives an important insight into the downstream signaling mechanisms of MGO, cPLA2-NF-κB, in endothelial apoptosis. - Highlights: • cPLA2 participated in MGO-induced HUVECs apoptosis. • Inhibition of NF-κB was involved in MGO-cPLA2-mediated cell apoptosis. • Antioxidant NAC attenuated MGO-induced cPLA2 activation and cell apoptosis.

The role of cPLA2 in Methylglyoxal-induced cell apoptosis of HUVECs

Energy Technology Data Exchange (ETDEWEB)

Yuan, Jie; Zhu, Chao; Hong, Yali; Sun, Zongxing; Fang, Xianjun [Jiangsu Provincial Key Lab of Cardiovascular Diseases and Molecular intervention, Department of Pharmacology, Nanjing Medical University, Nanjing 210029 (China); Wu, Biao, E-mail: wubiao@ncu.edu.cn [Department of Surgery, The First Affiliated Hospital, Nanchang University (China); Li, Shengnan, E-mail: snli@njmu.edu.cn [Jiangsu Provincial Key Lab of Cardiovascular Diseases and Molecular intervention, Department of Pharmacology, Nanjing Medical University, Nanjing 210029 (China)

2017-05-15

Methylglyoxal (MGO), a highly reactive dicarbonyl compound, is mainly formed as a byproduct of glycolysis. Elevated MGO level is known to induce apoptosis of vascular endothelial cells, which is implicated with progression of atherosclerosis and diabetic complications. However, the underlying mechanisms have not been exhaustively investigated yet. Here, we further characterized the mechanisms how MGO induced apoptosis in human umbilical vein endothelial cells (HUVECs). Our data revealed that cytosolic phospholipase A2 (cPLA2) played an important role in MGO-induced cell apoptosis. It was found that MGO could increase both the activity and expression of cPLA2. Inhibition of cPLA2 by Pyrrophenone (PYR) or siRNA significantly attenuated the MGO-induced apoptosis. Additionally, MGO time-dependently decreased the phosphorylation of nuclear factor κB (NF-κB). Pretreatment of the cells with NF-κB inhibitor, BAY11-7082, further increased MGO-induced apoptosis of HUVECs, indicating that NF-κB played a survival role in this MGO-induced apoptosis. Furthermore, in the presence of si-cPLA2 or PYR, MGO no longer decreased NF-κB phosphorylation. Beyond that, the antioxidant N-acetyl cysteine (NAC) could reverse the changes of both cPLA2 and NF-κB caused by MGO. p38, the upstream of cPLA2, was also significantly phosphorylated by MGO. However, p38 inhibitor failed to reverse the apoptosis induced by MGO. This study gives an important insight into the downstream signaling mechanisms of MGO, cPLA2-NF-κB, in endothelial apoptosis. - Highlights: • cPLA2 participated in MGO-induced HUVECs apoptosis. • Inhibition of NF-κB was involved in MGO-cPLA2-mediated cell apoptosis. • Antioxidant NAC attenuated MGO-induced cPLA2 activation and cell apoptosis.

related apoptosis-inducing ligand in transplastomic tobacco

African Journals Online (AJOL)

-inducing ligand (sTRAIL) can, as the whole length TRAIL protein, bind with its receptors and specifically induce the apoptosis of cancer cells; therefore, it has been developed as a potential therapeutic agent for various cancer treatments.

Interdependence of Bad and Puma during ionizing-radiation-induced apoptosis.

Science.gov (United States)

Toruno, Cristhian; Carbonneau, Seth; Stewart, Rodney A; Jette, Cicely

2014-01-01

Ionizing radiation (IR)-induced DNA double-strand breaks trigger an extensive cellular signaling response that involves the coordination of hundreds of proteins to regulate DNA repair, cell cycle arrest and apoptotic pathways. The cellular outcome often depends on the level of DNA damage as well as the particular cell type. Proliferating zebrafish embryonic neurons are highly sensitive to IR-induced apoptosis, and both p53 and its transcriptional target puma are essential mediators of the response. The BH3-only protein Puma has previously been reported to activate mitochondrial apoptosis through direct interaction with the pro-apoptotic Bcl-2 family proteins Bax and Bak, thus constituting the role of an "activator" BH3-only protein. This distinguishes it from BH3-only proteins like Bad that are thought to indirectly promote apoptosis through binding to anti-apoptotic Bcl-2 family members, thereby preventing the sequestration of activator BH3-only proteins and allowing them to directly interact with and activate Bax and Bak. We have shown previously that overexpression of the BH3-only protein Bad in zebrafish embryos supports normal embryonic development but greatly sensitizes developing neurons to IR-induced apoptosis. While Bad has previously been shown to play only a minor role in promoting IR-induced apoptosis of T cells in mice, we demonstrate that Bad is essential for robust IR-induced apoptosis in zebrafish embryonic neural tissue. Moreover, we found that both p53 and Puma are required for Bad-mediated radiosensitization in vivo. Our findings show the existence of a hierarchical interdependence between Bad and Puma whereby Bad functions as an essential sensitizer and Puma as an essential activator of IR-induced mitochondrial apoptosis specifically in embryonic neural tissue.

Cytosolic NADP(+)-dependent isocitrate dehydrogenase regulates cadmium-induced apoptosis.

Science.gov (United States)

Shin, Seoung Woo; Kil, In Sup; Park, Jeen-Woo

2010-04-01

Cadmium ions have a high affinity for thiol groups. Therefore, they may disturb many cellular functions. We recently reported that cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDPc) functions as an antioxidant enzyme to supply NADPH, a major source of reducing equivalents to the cytosol. Cadmium decreased the activity of IDPc both as a purified enzyme and in cultured cells. In the present study, we demonstrate that the knockdown of IDPc expression in HEK293 cells greatly enhances apoptosis induced by cadmium. Transfection of HEK293 cells with an IDPc small interfering RNA significantly decreased the activity of IDPc and enhanced cellular susceptibility to cadmium-induced apoptosis as indicated by the morphological evidence of apoptosis, DNA fragmentation and condensation, cellular redox status, mitochondria redox status and function, and the modulation of apoptotic marker proteins. Taken together, our results suggest that suppressing the expression of IDPc enhances cadmium-induced apoptosis of HEK293 cells by increasing disruption of the cellular redox status. Copyright 2009 Elsevier Inc. All rights reserved.

Tumor necrosis factor related apoptosis inducing ligand triggers apoptosis in dividing but not in differentiating human epidermal keratinocytes

NARCIS (Netherlands)

Jansen, Bastiaan J. H.; van Ruissen, Fred; Cerneus, Stefanie; Cloin, Wendy; Bergers, Mieke; van Erp, Piet E. J.; Schalkwijk, Joost

2003-01-01

Using serial analysis of gene expression we have previously identified the expression of several pro-apoptotic and anti-apoptotic genes in cultured human primary epidermal keratinocytes, including tumor necrosis factor related apoptosis inducing ligand (TRAIL). TRAIL is a potent inducer of apoptosis

Tempo enhances heat-induced apoptosis by mitochondrial targeting of Bax

International Nuclear Information System (INIS)

Zhao, Q.-L.; Fujiwara, Y.; Kondo, T.

2003-01-01

A stable membrane-permeable nitroxide, Tempo, exerts an SOD-like antioxidant activity against ROS. Reportedly, Tempo inhibits ROS-induced thymocyte apoptosis, while 10 mM Tempo activates JNK1 to induce apoptosis in breast cancer cells. We have observed that nontoxic 5 mM Tempo enhances suboptimal hyperthermia (44 deg C/10 min)-induced apoptosis in U937 cells. Here we report the enhancing mechanism, focusing on activation and targeting of Bax to mitochondria and cytochrome c release. Methods: U937 cells were treated with either Tempo (5 mM, 37 deg C/10 min), heating (44 deg C/10 min), or Tempo-plus-heating, washed and incubated for various times up to 6 h, until assessing apoptosis, mitochondrial potential (ΔΨ>), and amount of superoxide by flow cytometry using Annexin V-FITC/PI, TMRM, and dihydroethidium, respectively. Bax, Bcl-2 and Bcl-XL, and cytochrome c were detected by western blotting, activated Bax was by immunoprecipitation, and ATP was by a luciferase assay. Bax targeting to and cytochrome c release from mitochorndria were also detected immunocytochemically under fluorescent microscopy. Results and Discussion: Treatment of U937 cells with 5 mM Tempo for 10 min at 37 deg C or suboptimal heating (44 deg C/ 10 min) alone did not induce apoptosis. The combined treatment with 5 mM Tempo and 44 deg C for 10 min dramatically induced ∼90% apoptosis in 6 h, as did the 44 deg C/30 min heating. During the enhanced apoptosis, cytochrome c release progressed. Although signals of Bcl-2, Bcl-XL and Bax in cell lysates were not altered, Bax was specifically activated and translocated to mitochondria after the combined treatment. Further, loss of ΔΨ>and decreases in superoxide and ATP progressed after the combined treatment, suggesting that the treatment may disturb mitochondrial electron transport. Thus, Tempo sensitizes the heat-induced apoptosis through (1) targeting of Bax to mitochondria and releasing cytochrome c, and (2) mitochondrial dysfunction

Radiation-induced mitotic and meiotic aneuploidy in the yeast Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Parry, J.M.; Sharp, D.; Tippins, R.S.; Parry, E.M.

1979-01-01

A number of genetic systems are described which in yeast may be used to monitor the induction of chromosome aneuploidy during both mitotic and meiotic cell division. Using these systems the authors have been able to demonstrate the induction of both monosomic and trisomic cells in mitotically dividing cells and disomic spores in meiotically dividing cells after both UV light and X-ray exposure. (Auth.)

Ionizing radiation induces apoptosis in hematopoietic stem and progenitor cells

International Nuclear Information System (INIS)

Meng, A.; Zhou, D.; Geiger, H.; Zant, G.V.

2003-01-01

The aims of this study was to determine if ionizing radiation (IR) induces apoptosis in hematopoietic stem (HSC) and progenitor cells. Lin-cells were isolated from mouse bone marrow (BM) and pretreated with vehicle or 100 μM z-VAD 1 h prior to exposure to 4 Gy IR. The apoptotic and/or necrotic responses of these cells to IR were analyzed by measuring the annexin V and/or 7-AAD staining in HSC and progenitor populations using flow cytometry, and hematopoietic function of these cells was determined by CAFC assay. Exposure of Lin-cells to IR selectively decreased the numbers of HSC and progenitors in association with an increase in apoptosis in a time-dependent manner. Pretreatment of Lin- cells with z-VAD significantly inhibited IR-induced apoptosis and the decrease in the numbers of HSC and progenitors. However, IR alone or in combination with z-VAD did not lead to a significant increase in necrotic cell death in either HSC or progenitors. In addition, pretreatment of BM cells with z-VAD significantly attenuated IR-induced reduction in the frequencies of day-7, -28 and -35 CAFC. Exposure of HSC and progenitors to IR induces apoptosis. The induction of HSC and progenitor apoptosis contributes to IR-induced suppression of their hematopoietic function

Autophagy regulates chlorpyrifos-induced apoptosis in SH-SY5Y cells

International Nuclear Information System (INIS)

Park, Jae Hyeon; Lee, Jeong Eun; Shin, In Chul; Koh, Hyun Chul

2013-01-01

Recent studies have shown that up-regulation of autophagy may be a tractable therapeutic intervention for clearing disease-causing proteins, including α-synuclein, ubiquitin, and other misfolded or aggregated proteins in pesticide-induced neurodegeneration. In a previous study, we reported that chlorpyrifos (CPF)-induced mitochondria-dependent apoptosis is mediated through reactive oxygen species in SH-SY5Y cells. In this study, we explored a novel pharmacotherapeutic approach to prevent CPF neurotoxicity involving the regulation of autophagy. We investigated the modulation of CPF-induced apoptosis according to autophagy regulation. We found that CPF induced apoptosis in SH-SY5Y cells, as demonstrated by the activation of caspase-3 and nuclear condensation. In addition, we observed that cells treated with CPF underwent autophagic cell death by monitoring the expression of LC3-II and p62. Pretreatment with the autophagy inducer rapamycin significantly enhanced the cell viability of CPF-exposed cells, and the enhancement of cell viability was partially due to alleviation of CPF-induced apoptosis via a decrease in levels of cleaved caspase-3. Specifically, rapamycin pretreatment decreased Bax and increased Bcl-2 expression in mitochondria. In addition, rapamycin significantly decreased cytochrome c release in from mitochondria into the cytosol. However, pretreatment of cells with the autophagy inhibitor, 3-methyladenine (3MA), remarkably increased CPF toxicity in these cells; this with correlated with increased expression of Bax and decreased expression of Bcl-2 in mitochondria. Our results suggest that CPF-induced cytotoxicity is modified by autophagy regulation and that rapamycin protects against CPF-induced apoptosis by enhancing autophagy. Pharmacologic induction of autophagy by rapamycin may be a useful treatment strategy in neurodegenerative disorders. - Highlights: ► Chlorpyrifos (CPF) is cytotoxic to SH-SY5Y cells ► CPF-induced cytotoxicity is mediated by

Autophagy regulates chlorpyrifos-induced apoptosis in SH-SY5Y cells

Energy Technology Data Exchange (ETDEWEB)

Park, Jae Hyeon [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of); Lee, Jeong Eun [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Shin, In Chul [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Koh, Hyun Chul, E-mail: hckoh@hanyang.ac.kr [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of)

2013-04-01

Recent studies have shown that up-regulation of autophagy may be a tractable therapeutic intervention for clearing disease-causing proteins, including α-synuclein, ubiquitin, and other misfolded or aggregated proteins in pesticide-induced neurodegeneration. In a previous study, we reported that chlorpyrifos (CPF)-induced mitochondria-dependent apoptosis is mediated through reactive oxygen species in SH-SY5Y cells. In this study, we explored a novel pharmacotherapeutic approach to prevent CPF neurotoxicity involving the regulation of autophagy. We investigated the modulation of CPF-induced apoptosis according to autophagy regulation. We found that CPF induced apoptosis in SH-SY5Y cells, as demonstrated by the activation of caspase-3 and nuclear condensation. In addition, we observed that cells treated with CPF underwent autophagic cell death by monitoring the expression of LC3-II and p62. Pretreatment with the autophagy inducer rapamycin significantly enhanced the cell viability of CPF-exposed cells, and the enhancement of cell viability was partially due to alleviation of CPF-induced apoptosis via a decrease in levels of cleaved caspase-3. Specifically, rapamycin pretreatment decreased Bax and increased Bcl-2 expression in mitochondria. In addition, rapamycin significantly decreased cytochrome c release in from mitochondria into the cytosol. However, pretreatment of cells with the autophagy inhibitor, 3-methyladenine (3MA), remarkably increased CPF toxicity in these cells; this with correlated with increased expression of Bax and decreased expression of Bcl-2 in mitochondria. Our results suggest that CPF-induced cytotoxicity is modified by autophagy regulation and that rapamycin protects against CPF-induced apoptosis by enhancing autophagy. Pharmacologic induction of autophagy by rapamycin may be a useful treatment strategy in neurodegenerative disorders. - Highlights: ► Chlorpyrifos (CPF) is cytotoxic to SH-SY5Y cells ► CPF-induced cytotoxicity is mediated by

Modulation of iridovirus-induced apoptosis by endocytosis, early expression, JNK, and apical caspase

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Chitnis, Nilesh S.; D'Costa, Susan M.; Paul, Eric R.; Bilimoria, Shaen L.

2008-01-01

Chilo iridescent virus (CIV) is the type species for the family Iridoviridae, which are large, isometric, cytoplasmic dsDNA viruses. We examined the mechanism of apoptosis induction by CIV. High CIV doses (CIV XS ; 400 μg/ml), UV-irradiated virus (CIV UV ; 10 μg/ml) and CVPE (CIV protein extract; 10 μg/ml) induced apoptosis in 60% of treated Choristoneura fumiferana (IPRI-CF-124T) cells. Normal doses of infectious CIV (10 μg/ml) induced apoptosis in only 10% of C. fumiferana (CF) cells. Apoptosis was inhibited by Z-IETD-FMK, an apical caspase inhibitor, indicating that CIV-induced apoptosis requires caspase activity. The putative caspase in CF cells was designated Cf-caspase-i. CIV UV or CVPE enhanced Cf-caspase-i activity by 80% at 24 h relative to mock-treated cells. Since the MAP kinase pathway induces or inhibits apoptosis depending on the context, we used JNK inhibitor SP600125 and demonstrated drastic suppression of CVPE-induced apoptosis. Thus, the JNK signaling pathway is significant for apoptosis in this system. Virus interaction with the cell surface was not sufficient for apoptosis since CIV UV particles bound to polysterene beads failed to induce apoptosis. Endocytosis inhibitors (bafilomycin or ammonium chloride) negated apoptosis induction by CIV UV , CIV XS or CVPE indicating that entry through this mode is required. Given the weak apoptotic response to infectious CIV, we postulated that viral gene expression inhibited apoptosis. CIV infection of cells pretreated with cycloheximide induced apoptosis in 69% of the cells compared to 10% in normal infections. Furthermore, blocking viral DNA replication with aphidicolin or phosphonoacetic acid suppressed apoptosis and Cf-caspase-i activity, indicating that early viral expression is necessary for inhibition of apoptosis, and de novo synthesis of viral proteins is not required for induction. We show for the first time that, in a member of the family Iridoviridae, apoptosis: (i) requires entry and

The role of apoptosis in MCLR-induced developmental toxicity in zebrafish embryos

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Zeng, Cheng [College of Fisheries, Huazhong Agricultural University, Wuhan 430070 (China); Sun, Hong [Hubei Maternal and Child Health Hospital, Wuhan 430070 (China); Xie, Ping [Donghu Experimental Station of Lake Ecosystems, State Key Laboratory for Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072 (China); Wang, Jianghua; Zhang, Guirong; Chen, Nan [College of Fisheries, Huazhong Agricultural University, Wuhan 430070 (China); Yan, Wei, E-mail: Yanwei75126@163.com [Institute of Agricultural Quality Standards and Testing Technology, Hubei Academy of Agricultural Sciences, Wuhan 430064 (China); Li, Guangyu, E-mail: ligy2001@163.com [College of Fisheries, Huazhong Agricultural University, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070 (China)

2014-04-01

Highlights: • MCLR-induced apoptosis in the heart of developing embryos leads to the growth delay in zebrafish. • MCLR-triggered apoptosis might be induced by ROS. • P53–Bax–Bcl-2 and caspase-dependent apoptotic pathway contribute greatly to MCLR-induced apoptosis. Abstract: We previously demonstrated that cyanobacteria-derived microcystin–leucine–arginine (MCLR) is able to induce developing toxicity, such as malformation, growth delay and also decreased heart rates in zebrafish embryos. However, the molecular mechanisms by which MCLR induces its toxicity during the development of zebrafish remain largely unknown. Here, we evaluate the role of apoptosis in MCLR-induced developmental toxicity. Zebrafish embryos were exposed to various concentrations of MCLR (0, 0.2, 0.5, 2, and 5.0 mg L⁻¹ for 96 h, at which time reactive oxygen species (ROS) was significantly induced in the 2 and 5.0 mg L⁻¹ MCLR exposure groups. Acridine orange (AO) staining and terminal deoxynucleotide transferase-mediated deoxy-UTP nick end labelling (TUNEL) assay showed that MCLR exposure resulted in cell apoptosis. To test the apoptotic pathway, the expression pattern of several apoptotic-related genes was examined for the level of enzyme activity, gene and protein expression, respectively. The overall results demonstrate that MCLR induced ROS which consequently triggered apoptosis in the heart of developing zebrafish embryos. Our results also indicate that the p53–Bax–Bcl-2 pathway and the caspase-dependent apoptotic pathway play major roles in MCLR-induced apoptosis in the developing embryos.

Glucocorticoid Induced Leucine Zipper inhibits apoptosis of cardiomyocytes by doxorubicin

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Aguilar, David; Strom, Joshua; Chen, Qin M.

2014-01-01

Doxorubicin (Dox) is an indispensable chemotherapeutic agent for the treatment of various forms of neoplasia such as lung, breast, ovarian, and bladder cancers. Cardiotoxicity is a major concern for patients receiving Dox therapy. Previous work from our laboratory indicated that glucocorticoids (GCs) alleviate Dox-induced apoptosis in cardiomyocytes. Here we have found Glucocorticoid-Induced Leucine Zipper (GILZ) to be a mediator of GC-induced cytoprotection. GILZ was found to be induced in cardiomyocytes by GC treatment. Knocking down of GILZ using siRNA resulted in cancelation of GC-induced cytoprotection against apoptosis by Dox treatment. Overexpressing GILZ by transfection was able to protect cells from apoptosis induced by Dox as measured by caspase activation, Annexin V binding and morphologic changes. Western blot analyses indicate that GILZ overexpression prevented cytochrome c release from mitochondria and cleavage of caspase-3. When bcl-2 family proteins were examined, we found that GILZ overexpression causes induction of the pro-survival protein Bcl-xL. Since siRNA against Bcl-xL reverses GC induced cytoprotection, Bcl-xL induction represents an important event in GILZ-induced cytoprotection. Our data suggest that GILZ functions as a cytoprotective gene in cardiomyocytes. - Highlights: • Corticosteroids act as a cytoprotective agent in cardiomyocytes • Corticosteroids induce GILZ expression in cardiomyocytes • Elevated GILZ results in resistance against apoptosis induced by doxorubicin • GILZ induces Bcl-xL protein without inducing Bcl-xL mRNA

Caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress.

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Zhang, Qiang; Liu, Jianing; Chen, Shulan; Liu, Jing; Liu, Lijuan; Liu, Guirong; Wang, Fang; Jiang, Wenxin; Zhang, Caixia; Wang, Shuangyu; Yuan, Xiao

2016-04-01

It is well recognized that mandibular growth, which is caused by a variety of functional appliances, is considered to be the result of both neuromuscular and skeletal adaptations. Accumulating evidence has demonstrated that apoptosis plays an important role in the adaptation of skeletal muscle function. However, the underlying mechanism of apoptosis that is induced by stretch continues to be incompletely understood. Endoplasmic reticulum stress (ERS), a newly defined signaling pathway, initiates apoptosis. This study seeks to determine if caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress in myoblast and its underlying mechanism. Apoptosis was assessed by Hochest staining, DAPI staining and annexin V binding and PI staining. ER chaperones, such as GRP78, CHOP and caspase-12, were determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Furthermore, caspase-12 inhibitor was used to value the mechanism of the caspase-12 pathway. Apoptosis of myoblast, which is subjected to cyclic stretch, was observed in a time-dependent manner. We found that GRP78 mRNA and protein were significantly increased and CHOP and caspase-12 were activated in myoblast that was exposed to cyclic stretch. Caspase-12 inhibition reduced stretch-induced apoptosis, and caspase-12 activated caspase-3 to induce apoptosis. We concluded that caspase-12 played an important role in stretch-induced apoptosis that is associated by endoplasmic reticulum stress by activating caspase-3.

Dihydroartemisinin induces apoptosis preferentially via a Bim-mediated intrinsic pathway in hepatocarcinoma cells.

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Qin, Guiqi; Zhao, ChuBiao; Zhang, Lili; Liu, Hongyu; Quan, Yingyao; Chai, Liuying; Wu, Shengnan; Wang, Xiaoping; Chen, Tongsheng

2015-08-01

This report is designed to dissect the detail molecular mechanism by which dihydroartemisinin (DHA), a derivative of artemisinin, induces apoptosis in human hepatocellular carcinoma (HCC) cells. DHA induced a loss of the mitochondrial transmemberane potential (ΔΨm), release of cytochrome c, activation of caspases, and externalization of phosphatidylserine indicative of apoptosis induction. Compared with the modest inhibitory effects of silencing Bax, silencing Bak largely prevented DHA-induced ΔΨm collapse and apoptosis though DHA induced a commensurable activation of Bax and Bak, demonstrating a key role of the Bak-mediated intrinsic apoptosis pathway. DHA did not induce Bid cleavage and translocation from cytoplasm to mitochondria and had little effects on the expressions of Puma and Noxa, but did increase Bim and Bak expressions and decrease Mcl-1 expression. Furthermore, the cytotoxicity of DHA was remarkably reduced by silencing Bim, and modestly but significantly reduced by silencing Puma or Noxa. Silencing Bim or Noxa preferentially reduced DHA-induced Bak activation, while silencing Puma preferentially reduced DHA-induced Bax activation, demonstrating that Bim and to a lesser extent Noxa act as upstream mediators to trigger the Bak-mediated intrinsic apoptosis pathway. In addition, silencing Mcl-1 enhanced DHA-induced Bak activation and apoptosis. Taken together, our data demonstrate a crucial role of Bim in preferentially regulating the Bak/Mcl-1 rheostat to mediate DHA-induced apoptosis in HCC cells.

Osteoblasts Protect AML Cells from SDF-1-Induced Apoptosis

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Kremer, Kimberly N.; Dudakovic, Amel; McGee-Lawrence, Meghan E.; Philips, Rachael L.; Hess, Allan D.; Smith, B. Douglas; van Wijnen, Andre J.; Karp, Judith E.; Kaufmann, Scott H.; Westendorf, Jennifer J.; Hedin, Karen E.

2014-01-01

The bone marrow provides a protective environment for acute myeloid leukemia (AML) cells that often allows leukemic stem cells to survive standard chemotherapeutic regimens. Targeting these leukemic stem cells within the bone marrow is critical for preventing relapse. We recently demonstrated that SDF-1, a chemokine abundant in the bone marrow, induces apoptosis in AML cell lines and in patient samples expressing high levels of its receptor, CXCR4. Here we show that a subset of osteoblast lineage cells within the bone marrow can protect AML cells from undergoing apoptosis in response to the SDF-1 naturally present in that location. In co-culture systems, osteoblasts at various stages of differentiation protected AML cell lines and patient isolates from SDF-1-induced apoptosis. The differentiation of the osteoblast cell lines, MC3T3 and W-20-17, mediated this protection via a cell contact-independent mechanism. In contrast, bone marrow-derived mesenchymal cells, the precursors of osteoblasts, induced apoptosis in AML cells via a CXCR4-dependent mechanism and failed to protect AML cells from exogenously added SDF-1. These results indicate that osteoblasts in the process of differentiation potently inhibit the SDF-1-driven apoptotic pathway of CXCR4-expressing AML cells residing in the bone marrow. Drugs targeting this protective mechanism could potentially provide a new approach to treating AML by enhancing the SDF-1-induced apoptosis of AML cells residing within the bone marrow microenvironment. PMID:24851270

Increased radiosensitivity and radiation-induced apoptosis in SRC-3 knockout mice

International Nuclear Information System (INIS)

Jin Jie; Wang Yu; Xu Yang; Chen Shilei; Wang Junping; Ran Xinze; Su Yongping; Wang Jin

2014-01-01

Steroid receptor coactivator-3 (SRC-3), a multifunctional transcriptional coactivator, plays an important role in regulation of cell apoptosis in chemoresistant cancer cells. However, its role in radiation-induced apoptosis in hematopoietic cells is still unclear. In this study, we used SRC-3 knockout (SRC-3 -/- ) mice to assess the role of SRC-3 in radiation-induced hematopoietic injury in vivo. After a range of doses of irradiation, SRC-3 -/- mice exhibited lower counts of peripheral blood cells and bone marrow (BM) mononuclear cells and excessive BM depression, which resulted in a significantly higher mortality compared with wildtype mice. Moreover, BM mononuclear cells obtained from SRC-3 -/- mice showed a remarkable increase in radiation-induced apoptosis. Collectively, our data demonstrate that SRC-3 plays a role in radiation-induced apoptosis of BM hematopoietic cells. Regulation of SRC-3 might influence the radiosensitivity of hematopoietic cells, which highlights a potential therapeutic target for radiation-induced hematopoietic injury. (author)

Protection of betulin against cadmium-induced apoptosis in hepatoma cells

International Nuclear Information System (INIS)

Oh, Seon-Hee; Choi, Jeong-Eun; Lim, Sung-Chul

2006-01-01

The protective effects of betulin (BT) against cadmium (Cd)-induced cytotoxicity have been previously reported. However, the mechanisms responsible for these protective effects are unclear. Therefore, this study investigated the mechanisms responsible for the protection of BT against Cd-induced cytotoxicity in human hepatoma cell lines. The protection of BT against Cd cytotoxicity was more effective in the HepG2 than in the Hep3B cells. The protection of BT on Cd-induced cytotoxicity in the HepG2 cells appeared to be related to the inhibition of apoptosis, as determined by PI staining and DNA fragmentation analysis. The anti-apoptosis exerted by BT involved the blocking of Cd-induced reactive oxygen species (ROS) generation, the abrogation of the Cd-induced Fas upregulation, the blocking of caspase-8-dependent Bid activation, and subsequent inhibition of mitochondrial pathway. The BT pretreatment did not affect the p21 and p53 expression levels, when compared with those of the treated cells with Cd alone. BT induced the transient S phase arrest at an early stage and the G /G 1 arrest at a relatively late stage, but it did not observe the sub-G1 apoptotic peak. In the Hep3B cells, Cd did not induce ROS generation. The BT pretreatment partially inhibited the Cd-induced apoptosis, which was related with the incomplete blockage in caspase-9 or -3 activation, as well as in Bax activation. Taken together, it was found that Cd can induce apoptosis via the Fas-dependent and -independent apoptosis pathways. However, the observed protective effects of BT were clearly more sensitive to Fas-expressing HepG2 cells than to Fas-deficient Hep3B cells

JS-K promotes apoptosis by inducing ROS production in human prostate cancer cells.

Science.gov (United States)

Qiu, Mingning; Chen, Lieqian; Tan, Guobin; Ke, Longzhi; Zhang, Sai; Chen, Hege; Liu, Jianjun

2017-03-01

Reactive oxygen species (ROS) are chemical species that alter redox status, and are responsible for inducing carcinogenesis. The purpose of the present study was to assess the effects of the glutathione S transferase-activated nitric oxide donor prodrug, JS-K, on ROS accumulation and on proliferation and apoptosis in human prostate cancer cells. Cell proliferation and apoptosis, ROS accumulation and the activation of the mitochondrial signaling pathway were measured. The results demonstrated that JS-K may inhibit prostate cancer cell growth in a dose- and time-dependent manner, and induce ROS accumulation and apoptosis in a dose-dependent manner. With increasing concentrations of JS-K, expression of pro-apoptotic proteins increased, but Bcl-2 expression decreased. Additionally, the antioxidant N-acetylcysteine reversed JS-K-induced cell apoptosis; conversely, the pro-oxidant glutathione disulfide exacerbated JS-K-induced apoptosis. In conclusion, the data suggest that JS-K induces prostate cancer cell apoptosis by increasing ROS levels.

Ceramide-Induced Apoptosis in Renal Tubular Cells: A Role of Mitochondria and Sphingosine-1-Phoshate

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Ueda, Norishi

2015-01-01

Ceramide is synthesized upon stimuli, and induces apoptosis in renal tubular cells (RTCs). Sphingosine-1 phosphate (S1P) functions as a survival factor. Thus, the balance of ceramide/S1P determines ceramide-induced apoptosis. Mitochondria play a key role for ceramide-induced apoptosis by altered mitochondrial outer membrane permeability (MOMP). Ceramide enhances oligomerization of pro-apoptotic Bcl-2 family proteins, ceramide channel, and reduces anti-apoptotic Bcl-2 proteins in the MOM. This process alters MOMP, resulting in generation of reactive oxygen species (ROS), cytochrome C release into the cytosol, caspase activation, and apoptosis. Ceramide regulates apoptosis through mitogen-activated protein kinases (MAPKs)-dependent and -independent pathways. Conversely, MAPKs alter ceramide generation by regulating the enzymes involving ceramide metabolism, affecting ceramide-induced apoptosis. Crosstalk between Bcl-2 family proteins, ROS, and many signaling pathways regulates ceramide-induced apoptosis. Growth factors rescue ceramide-induced apoptosis by regulating the enzymes involving ceramide metabolism, S1P, and signaling pathways including MAPKs. This article reviews evidence supporting a role of ceramide for apoptosis and discusses a role of mitochondria, including MOMP, Bcl-2 family proteins, ROS, and signaling pathways, and crosstalk between these factors in the regulation of ceramide-induced apoptosis of RTCs. A balancing role between ceramide and S1P and the strategy for preventing ceramide-induced apoptosis by growth factors are also discussed. PMID:25751724

Mineral trioxide aggregate: part 2 - a review of the material aspects.

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Malhotra, Neeraj; Agarwal, Antara; Mala, Kundabala

2013-03-01

The purpose of this two-part series is to review the composition, properties, and products of mineral trioxide aggregate (MTA) materials. PubMed and MedLine electronic databases were used to identify scientific papers from January 1991 to May 2010. Based on the selected inclusion criteria, citations were referenced from the scientific peer-reviewed dental literature. Mineral trioxide aggregate is a refined form of the parent compound, Portland cement (PC), and demonstrates a strong biocompatibility due to the high pH level and the material's ability to form hydroxyapatite. Mineral trioxide aggregate materials provide better microleakage protection than traditional endodontic materials as observed in findings from dye-leakage, fluid-filtration, protein-leakage, and bacterial penetration-leakage studies and has been recognized as a bioactive material. Various MTA commercial products are available, including gray mineral trioxide aggregate (GMTA), white mineral trioxide aggregate (WMTA), and mineral trioxide aggregate-Angelus (AMTA). Although these materials are indicated for various dental uses and applications, long-term in-vivo clinical studies are needed. Part 1 of this article highlighted and discussed the composition and characteristics of the material. Part 2 provides an overview of commercially available MTA materials.

Noxa/Mcl-1 Balance Regulates Susceptibility of Cells to Camptothecin-Induced Apoptosis1

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Mei, Yide; Xie, Chongwei; Xie, Wei; Tian, Xu; Li, Mei; Wu, Mian

2007-01-01

Although camptothecin (CPT) has been reported to induce apoptosis in various cancer cells, the molecular details of this regulation remain largely unknown. In this study, we demonstrate that BH3-only protein Noxa is upregulated during CPT-induced apoptosis, which is independent of p53. In addition, we show that phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway is responsible for Noxa's induction. Luciferase assay and cAMP response element binding protein (CREB) knockdown experiments further demonstrate that CREB is involved in the transcriptional upregulation of Noxa. Moreover, blocking Noxa expression using specific small interfering ribonucleic acid (siRNA) significantly reduces the apoptosis in response to CPT, indicating that Noxa is an essential mediator for CPT-induced apoptosis. Interestingly, antiapoptotic Mcl-1 was also upregulated through PI3K/Akt signaling pathway upon CPT treatment. Using immunoprecipitation assay, Noxa was found to interact with Mcl-1 in the presence or absence of CPT. Knockdown of Mcl-1 expression by short hairpin ribonucleic acid (shRNA) was shown to potentiate CPT-induced apoptosis. Consistently, ectopic overexpression of Mcl-1 rescued cells from apoptosis induced by CPT. Cells coexpressing Noxa and Mcl-1 at different ratio correlates well with the extent of apoptosis, suggesting that the balance between Noxa and Mcl-1 may determine the susceptibility of HeLa cells to CPT-induced apoptosis. PMID:17971907

Arsenic trioxide (As2O3) induced calcium signals and cytotoxicity in two human cell lines: SY-5Y neuroblastoma and 293 embryonic kidney (HEK)

International Nuclear Information System (INIS)

Florea, Ana-Maria; Splettstoesser, Frank; Buesselberg, Dietrich

2007-01-01

Arsenic trioxide (As 2 O 3 ) has anticancer properties; however, its use also leads to neuro-, hepato- or nephro-toxicity, and therefore, it is important to understand the mechanism of As 2 O 3 toxicity. We studied As 2 O 3 influence on intracellular calcium ([Ca 2+ ] i ) homeostasis of human neuroblastoma SY-5Y and embryonic kidney cells (HEK 293).We also relate the As 2 O 3 induced [Ca 2+ ] i modifications with cytotoxicity. We used Ca 2+ sensitive dyes (fluo-4 and rhod-2) combined with laser scanning microscopy or fluorescence activated cell sorting to measure Ca 2+ changes during the application of As 2 O 3 and we approach evaluation of cytotoxicity. As 2 O 3 (1 μM) increased [Ca 2+ ] i in SY-5Y and HEK 293 cells. Three forms of [Ca 2+ ] i -elevations were found: (1) steady-state increases (2) transient [Ca 2+ ] i -elevations and (3) Ca 2+ -spikes. [Ca 2+ ] i modifications were independent from extracellular Ca 2+ but dependent on internal calcium stores. The effect was not reversible. Inositol triphosphate (IP 3 ) and ryanodine (Ry) receptors are involved in regulation of signals induced by As 2 O 3 . 2-APB and dantrolene significantly reduced the [Ca 2+ ] i -rise (p 2+ ] i -elevation or spiking. This indicates that other Ca 2+ regulating mechanisms are involved. In cytotoxicity tests As 2 O 3 significantly reduced cell viability in both cell types. Staining with Hoechst 33342 showed occurrence of apoptosis and DNA damage. Our data suggest that [Ca 2+ ] i is an important messenger in As 2 O 3 induced cell death

O-GlcNAcylation regulates ischemia-induced neuronal apoptosis through AKT signaling.

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Shi, Jianhua; Gu, Jin-hua; Dai, Chun-ling; Gu, Jianlan; Jin, Xiaoxia; Sun, Jianming; Iqbal, Khalid; Liu, Fei; Gong, Cheng-Xin

2015-09-28

Apoptosis plays an important role in neural development and neurological disorders. In this study, we found that O-GlcNAcylation, a unique protein posttranslational modification with O-linked β-N-acetylglucosamine (GlcNAc), promoted apoptosis through attenuating phosphorylation/activation of AKT and Bad. By using co-immunoprecipitation and mutagenesis techniques, we identified O-GlcNAc modification at both Thr308 and Ser473 of AKT. O-GlcNAcylation-induced apoptosis was attenuated by over-expression of AKT. We also found a dynamic elevation of protein O-GlcNAcylation during the first four hours of cerebral ischemia, followed by continuous decline after middle cerebral artery occlusion (MCAO) in the mouse brain. The elevation of O-GlcNAcylation coincided with activation of cell apoptosis. Finally, we found a negative correlation between AKT phosphorylation and O-GlcNAcylation in ischemic brain tissue. These results indicate that cerebral ischemia induces a rapid increase of O-GlcNAcylation that promotes apoptosis through down-regulation of AKT activity. These findings provide a novel mechanism through which O-GlcNAcylation regulates ischemia-induced neuronal apoptosis through AKT signaling.

Knockdown of HIF-1α and IL-8 induced apoptosis of hepatocellular carcinoma triggers apoptosis of vascular endothelial cells.

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Choi, Sung Hoon; Park, Jun Yong; Kang, Wonseok; Kim, Seung Up; Kim, Do Young; Ahn, Sang Hoon; Ro, Simon Wonsang; Han, Kwang-Hyub

2016-01-01

A local hypoxic microenvironment is one of the most important characteristics of solid tumors. Hypoxia inducible factor-1α (HIF-1α) and Interleukin-8 (IL-8) activate tumor survival from hypoxic-induced apoptosis in each pathway. This study aimed to evaluate whether knockdown of HIF-1α and IL-8 induced apoptosis of the hepatocellular carcinoma (HCC) and endothelial cell lines. HCC cell lines were infected with adenovirus-expressing shRNA for HIF-1α and IL-8 and maintained under hypoxic conditions (1% O2, 24 h). The expression levels of HIF-1α and both apoptotic and growth factors were examined by real-time quantitative PCR and western blot. We also investigated apoptosis by TUNEL assay (FACS and Immunofluorescence) and measured the concentration of cytochrome C. Inhibition of HIF-1α and IL-8 up-regulated the expression of apoptotic factors while downregulating anti-apoptotic factors simultaneously. Knockdown of HIF-1α and IL-8 increased the concentration of cytochrome C and enhanced DNA fragmentation in HCC cell lines. Moreover, culture supernatant collected from the knockdown of HIF-1α and IL-8 in HCC cell lines induced apoptosis in human umbilical vein endothelial cells under hypoxia, and the expression of variable apoptotic ligand increased from HCC cell lines, time-dependently. These data suggest that adenovirus-mediated knockdown of HIF-1α and IL-8 induced apoptosis in HCC cells and triggered apoptosis of vascular endothelial cells.

Apoptosis induced by high- and low-LET radiations

International Nuclear Information System (INIS)

Hendry, J.H.; Potten, C.S.; Merritt, A.

1995-01-01

Cell death after irradiation occurs by apoptosis in certain cell populations in tissues. The phenomenon also occurs after high linear energy transfer (LET) irradiation, and the relative biological effectiveness (RBE) is 3 to 4 (with respect to low-LET radiation and apoptosis in intestinal crypts) for neutrons with energies of 14 MeV and up to 600 MeV. It is thought that p53 plays a role in the phenomenon, as radiation-induced apoptosis is not observed in p53-null animals. (orig.)

Mechanisms of methicillin-resistant Staphylococcus aureus pneumonia-induced intestinal epithelial apoptosis.

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Perrone, Erin E; Jung, Enjae; Breed, Elise; Dominguez, Jessica A; Liang, Zhe; Clark, Andrew T; Dunne, W Michael; Burd, Eileen M; Coopersmith, Craig M

2012-07-01

Methicillin-resistant Staphylococcus aureus (MRSA) pneumonia-induced sepsis is a common cause of morbidity in the intensive care unit. Although pneumonia is initiated in the lungs, extrapulmonary manifestations occur commonly. In light of the key role the intestine plays in the pathophysiology of sepsis, we sought to determine whether MRSA pneumonia induces intestinal injury. FVB/N mice were subjected to MRSA or sham pneumonia and killed 24 h later. Septic animals had a marked increase in intestinal epithelial apoptosis by both hematoxylin-eosin and active caspase 3 staining. Methicillin-resistant S. aureus-induced intestinal apoptosis was associated with an increase in the expression of the proapoptotic proteins Bid and Bax and the antiapoptotic protein Bcl-xL in the mitochondrial pathway. In the receptor-mediated pathway, MRSA pneumonia induced an increase in Fas ligand but decreased protein levels of Fas, FADD, pFADD, TNF-R1, and TRADD. To assess the functional significance of these changes, MRSA pneumonia was induced in mice with genetic manipulations in proteins in either the mitochondrial or receptor-mediated pathways. Both Bid-/- mice and animals with intestine-specific overexpression of Bcl-2 had decreased intestinal apoptosis compared with wild-type animals. In contrast, Fas ligand-/- mice had no alterations in apoptosis. To determine if these findings were organism-specific, similar experiments were performed in mice subjected to Pseudomonas aeruginosa pneumonia. Pseudomonas aeruginosa induced gut apoptosis, but unlike MRSA, this was associated with increased Bcl-2 and TNF-R1 and decreased Fas. Methicillin-resistant S. aureus pneumonia thus induces organism-specific changes in intestinal apoptosis via changes in both the mitochondrial and receptor-mediated pathways, although the former may be more functionally significant.

Enhanced suppression of tumor growth by concomitant treatment of human lung cancer cells with suberoylanilide hydroxamic acid and arsenic trioxide

International Nuclear Information System (INIS)

Chien, Chia-Wen; Yao, Ju-Hsien; Chang, Shih-Yu; Lee, Pei-Chih; Lee, Te-Chang

2011-01-01

The efficacy of arsenic trioxide (ATO) against acute promyelocytic leukemia (APL) and relapsed APL has been well documented. ATO may cause DNA damage by generating reactive oxygen intermediates. Suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, modulates gene and protein expression via histone-dependent or -independent pathways that may result in chromatin decondensation, cell cycle arrest, differentiation, and apoptosis. We investigated whether ATO and SAHA act synergistically to enhance the death of cancer cells. Our current findings showed that combined treatment with ATO and SAHA resulted in enhanced suppression of non-small-cell lung carcinoma in vitro in H1299 cells and in vivo in a xenograft mouse model. Flow cytometric analysis of annexin V+ cells showed that apoptotic cell death was significantly enhanced after combined treatment with ATO and SAHA. At the doses used, ATO did not interfere with cell cycle progression, but SAHA induced p21 expression and led to G1 arrest. A Comet assay demonstrated that ATO, but not SAHA, induced DNA strand breaks in H1299 cells; however, co-treatment with SAHA significantly increased ATO-induced DNA damage. Moreover, SAHA enhanced acetylation of histone H3 and sensitized genomic DNA to DNase I digestion. Our results suggest that SAHA may cause chromatin relaxation and increase cellular susceptibility to ATO-induced DNA damage. Combined administration of SAHA and ATO may be an effective approach to the treatment of lung cancer. -- Highlights: ► ATO and SAHA are therapeutic agents with different action modes. ► Combination of ATO and SAHA synergistically inhibits tumor cell growth. ► SAHA loosens chromatin structure resulting in increased sensitivity to DNase I. ► ATO-induced DNA damage and apoptosis are enhanced by co-treatment with SAHA.

Evaluation of the neuronal apoptotic pathways involved in cytoskeletal disruption-induced apoptosis.

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Jordà, Elvira G; Verdaguer, Ester; Jimenez, Andrés; Arriba, S Garcia de; Allgaier, Clemens; Pallàs, Mercè; Camins, Antoni

2005-08-01

The cytoskeleton is critical to neuronal functioning and survival. Cytoskeletal alterations are involved in several neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. We studied the possible pathways involved in colchicine-induced apoptosis in cerebellar granule neurons (CGNs). Although colchicine evoked an increase in caspase-3, caspase-6 and caspase-9 activation, selective caspase inhibitors did not attenuate apoptosis. Inhibitors of other cysteine proteases such as PD150606 (a calpain-specific inhibitor), Z-Phe-Ala fluoromethyl ketone (a cathepsins-inhibitors) and N(alpha)-p-tosyl-l-lysine chloromethyl ketone (serine-proteases inhibitor) also had no effect on cell death/apoptosis induced by colchicine. However, BAPTA-AM 10 microM (intracellular calcium chelator) prevented apoptosis mediated by cytoskeletal alteration. These data indicate that calcium modulates colchicine-induced apoptosis in CGNs. PARP-1 inhibitors did not prevent apoptosis mediated by colchicine. Finally, colchicine-induced apoptosis in CGNs was attenuated by kenpaullone, a cdk5 inhibitor. Kenpaullone and indirubin also prevented cdk5/p25 activation mediated by colchicine. These findings indicate that cytoskeletal alteration can compromise cdk5 activation, regulating p25 formation and suggest that cdk5 inhibitors attenuate apoptosis mediated by cytoskeletal alteration. The present data indicate the potential therapeutic value of drugs that prevent the formation of p25 for the treatment of neurodegenerative disorders.

[Study on thaspine in inducing apoptosis of A549 cell].

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Zhang, Yan-min; He, Lang-chong

2007-04-01

To investigate the effect of thaspine on the cellular proliferation, apoptosis and cell cycle in A549 cell line. A549 cell was cultured with different concentrations of thaspine. Cellular proliferation was detected with MTT, apoptosis and cell cycle were checked with Flow Cytometer, and change of microstructure was observed by transmission electron microscope. Thaspine could inhibit the proliferation and induce apoptosis of A549 cell in a time-dose dependent manner. Cell cycle was significantly stopped at the S phase by thaspine with FCM technology. Under electronic microscope, the morphology of A549 cell showed nuclear karyopycnosis, chromatin agglutination and typical apoptotic body when the cell was treated with thaspine. Thaspine has the effects of anti-tumor and inducing apoptosis.

Single-walled carbon nanotube-induced mitotic disruption⋆

OpenAIRE

Sargent, L.M.; Hubbs, A.F.; Young, S.-H.; Kashon, M.L.; Dinu, C.Z.; Salisbury, J.L.; Benkovic, S.A.; Lowry, D.T.; Murray, A.R.; Kisin, E.R.; Siegrist, K.J.; Battelli, L.; Mastovich, J.; Sturgeon, J.L.; Bunker, K.L.

2011-01-01

Carbon nanotubes were among the earliest products of nanotechnology and have many potential applications in medicine, electronics, and manufacturing. The low density, small size, and biological persistence of carbon nanotubes create challenges for exposure control and monitoring and make respiratory exposures to workers likely. We have previously shown mitotic spindle aberrations in cultured primary and immortalized human airway epithelial cells exposed to 24, 48 and 96 μg/cm2 single-walled c...

Wnt1 inhibits hydrogen peroxide-induced apoptosis in mouse cardiac stem cells.

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Jingjin Liu

Full Text Available BACKGROUND: Because of their regenerative and paracrine abilities, cardiac stem cells (CSCs are the most appropriate, optimal and promising candidates for the development of cardiac regenerative medicine strategies. However, native and exogenous CSCs in ischemic hearts are exposed to various pro-apoptotic or cytotoxic factors preventing their regenerative and paracrine abilities. METHODS AND RESULTS: We examined the effects of H2O2 on mouse CSCs (mCSCs, and observed that hydrogen peroxide (H2O2 treatment induces mCSCs apoptosis via the caspase 3 pathway, in a dose-dependent manner. We then examined the effects of Wnt1 over-expression on H2O2-induced apoptosis in mCSCs and observed that Wnt1 significantly decreased H2O2-induced apoptosis in mCSCs. On the other hand, inhibition of the canonical Wnt pathway by the secreted frizzled related protein 2 (SFRP2 or knockdown of β-catenin in mCSCs reduced cells resistance to H2O2-induced apoptosis, suggesting that Wnt1 predominantly prevents H2O2-induced apoptosis through the canonical Wnt pathway. CONCLUSIONS: Our results provide the first evidences that Wnt1 plays an important role in CSCs' defenses against H2O2-induced apoptosis through the canonical Wnt1/GSK3β/β-catenin signaling pathway.

The effects of pulse cycloheximide treatments on the light-induced recovery of mitotic divisions in antheridial filaments of Chara vulgaris

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Maria Kwiatkowska

2014-01-01

Full Text Available Within the proliferative period of spermatogenesis in Chara vulgaris, the progression throughout successive cell divisions in antheridial filaments is greatly influenced by changes in photoperiodic conditions. The extended (4-day period of total darkness brings about cell cycle arrest in the early G2 phase. The recovery of mitosis requires about 20 hours of exposition to light. In the present study, a series of 8 pulse incubations of plants in cycloheximide (Cx; 2.5 mg/I, 2.5 h each pulse were performed within the period elapsing till the resumption of mitotic divisions. Depending on the time of treatment, the effects induced by Cx vary considerably. Within the first 10 hs of exposition to light, incubations with Cx result in the delays of mitoses; within the period between the 10th and the 17th h, mitotic divisions become blocked, and, following the 17.5 h of light-induced recovery, no influence of Cx is noticed on mitotic activity, as compared with the untreaed control plants. The obtained results provide a starting point for the characteristic of proteins synthesized during the G2 phase and a preliminary study on those mechanisms, which become engaged in the regulation of the G1-deficient cell cycle evidenced in antheridial filaments of Chara.

Influenza virus induces apoptosis via BAD-mediated mitochondrial dysregulation.

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Tran, Anh T; Cortens, John P; Du, Qiujiang; Wilkins, John A; Coombs, Kevin M

2013-01-01

Influenza virus infection results in host cell death and major tissue damage. Specific components of the apoptotic pathway, a signaling cascade that ultimately leads to cell death, are implicated in promoting influenza virus replication. BAD is a cell death regulator that constitutes a critical control point in the intrinsic apoptosis pathway, which occurs through the dysregulation of mitochondrial outer membrane permeabilization and the subsequent activation of downstream apoptogenic factors. Here we report a novel proviral role for the proapoptotic protein BAD in influenza virus replication. We show that influenza virus-induced cytopathology and cell death are considerably inhibited in BAD knockdown cells and that both virus replication and viral protein production are dramatically reduced, which suggests that virus-induced apoptosis is BAD dependent. Our data showed that influenza viruses induced phosphorylation of BAD at residues S112 and S136 in a temporal manner. Viral infection also induced BAD cleavage, late in the viral life cycle, to a truncated form that is reportedly a more potent inducer of apoptosis. We further demonstrate that knockdown of BAD resulted in reduced cytochrome c release and suppression of the intrinsic apoptotic pathway during influenza virus replication, as seen by an inhibition of caspases-3, caspase-7, and procyclic acidic repetitive protein (PARP) cleavage. Our data indicate that influenza viruses carefully modulate the activation of the apoptotic pathway that is dependent on the regulatory function of BAD and that failure of apoptosis activation resulted in unproductive viral replication.

Axin localizes to mitotic spindles and centrosomes in mitotic cells

International Nuclear Information System (INIS)

Kim, Shi-Mun; Choi, Eun-Jin; Song, Ki-Joon; Kim, Sewoon; Seo, Eunjeong; Jho, Eek-Hoon; Kee, Sun-Ho

2009-01-01

Wnt signaling plays critical roles in cell proliferation and carcinogenesis. In addition, numerous recent studies have shown that various Wnt signaling components are involved in mitosis and chromosomal instability. However, the role of Axin, a negative regulator of Wnt signaling, in mitosis has remained unclear. Using monoclonal antibodies against Axin, we found that Axin localizes to the centrosome and along mitotic spindles. This localization was suppressed by siRNA specific for Aurora A kinase and by Aurora kinase inhibitor. Interestingly, Axin over-expression altered the subcellular distribution of Plk1 and of phosphorylated glycogen synthase kinase (GSK3β) without producing any notable changes in cellular phenotype. In the presence of Aurora kinase inhibitor, Axin over-expression induced the formation of cleavage furrow-like structures and of prominent astral microtubules lacking midbody formation in a subset of cells. Our results suggest that Axin modulates distribution of Axin-associated proteins such as Plk1 and GSK3β in an expression level-dependent manner and these interactions affect the mitotic process, including cytokinesis under certain conditions, such as in the presence of Aurora kinase inhibitor

Enhanced 15-HPETE production during oxidant stress induces apoptosis of endothelial cells.

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Sordillo, Lorraine M; Weaver, James A; Cao, Yu-Zhang; Corl, Chris; Sylte, Matt J; Mullarky, Isis K

2005-05-01

Oxidant stress plays an important role in the etiology of vascular diseases by increasing rates of endothelial cell apoptosis, but few data exist on the mechanisms involved. Using a unique model of oxidative stress based on selenium deficiency (-Se), the effects of altered eicosanoid production on bovine aortic endothelial cells (BAEC) apoptosis was evaluated. Oxidant stress significantly increased the immediate oxygenation product of arachidonic acid metabolized by the 15-lipoxygenase pathway, 15-hydroxyperoxyeicosatetraenoic acid (15-HPETE). Treatment of -Se BAEC with TNFalpha/cyclohexamide (CHX) exhibited elevated levels of apoptosis, which was significantly reduced by the addition of a specific 15-lipoxygenase inhibitor PD146176. Furthermore, the addition of 15-HPETE to PD146176-treated BAEC, partially restored TNF/CHX-induced apoptosis. Increased exposure to 15-HPETE induced apoptosis, as determined by internucleosomal DNA fragmentation, chromatin condensation, caspase-3 activation, and caspase-9 activation, which suggests mitochondrial dysfunction. The expression of Bcl-2 protein also was decreased in -Se BAEC. Addition of a caspase-9 inhibitor (LEHD-fmk) completely blocked 15-HPETE-induced chromatin condensation in -Se BAEC, suggesting that 15-HPETE-induced apoptosis is caspase-9 dependent. Increased apoptosis of BAEC as a result of oxidant stress and subsequent production of 15-HPETE may play a critical role in a variety of inflammatory based diseases.

Myostatin induces mitochondrial metabolic alteration and typical apoptosis in cancer cells

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Liu, Y; Cheng, H; Zhou, Y; Zhu, Y; Bian, R; Chen, Y; Li, C; Ma, Q; Zheng, Q; Zhang, Y; Jin, H; Wang, X; Chen, Q; Zhu, D

2013-01-01

Myostatin, a member of the transforming growth factor-β superfamily, regulates the glucose metabolism of muscle cells, while dysregulated myostatin activity is associated with a number of metabolic disorders, including muscle cachexia, obesity and type II diabetes. We observed that myostatin induced significant mitochondrial metabolic alterations and prolonged exposure of myostatin induced mitochondria-dependent apoptosis in cancer cells addicted to glycolysis. To address the underlying mechanism, we found that the protein levels of Hexokinase II (HKII) and voltage-dependent anion channel 1 (VDAC1), two key regulators of glucose metabolisms as well as metabolic stress-induced apoptosis, were negatively correlated. In particular, VDAC1 was dramatically upregulated in cells that are sensitive to myostatin treatment whereas HKII was downregulated and dissociated from mitochondria. Myostatin promoted the translocation of Bax from cytosol to mitochondria, and knockdown of VDAC1 inhibited myostatin-induced Bax translocation and apoptosis. These apoptotic changes can be partially rescued by repletion of ATP, or by ectopic expression of HKII, suggesting that perturbation of mitochondrial metabolism is causally linked with subsequent apoptosis. Our findings reveal novel function of myostatin in regulating mitochondrial metabolism and apoptosis in cancer cells. PMID:23412387

Arsenic trioxide decreases the amount and inhibits the function of regulatory T cells, which may contribute to its efficacy in the treatment of acute promyelocytic leukemia.

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Xu, Wen; Li, Xiaoxia; Quan, Lina; Yao, Jiying; Mu, Guannan; Guo, Jingjie; Wang, Yitong

2018-03-01

Arsenic trioxide (ATO) exhibits substantial clinical efficacy in the treatment of acute promyelocytic leukemia (APL). Here, we investigated whether ATO exerts its efficacy by affecting regulatory T (Treg) cells. We determined whether ATO treatment influenced the amount and function of purified Treg cells. We also examined the effect of ATO treatment on Treg cells from APL patients. ATO treatment induced apoptosis in purified Treg cells and dampened the inhibition of effector T (Teff) cells proliferation and the secretion of cytokine by Treg cells. Treg cell levels in the peripheral blood and serum IL-10 levels were dramatically decreased in APL patients after single ATO treatment. In summary, our results show that ATO decreases the amount and inhibits the function of Treg cells, thereby enhancing Teff cell function and overall anti-tumor immunity.

Robust mitotic entry is ensured by a latching switch

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Chloe Tuck

2013-07-01

Cell cycle events are driven by Cyclin dependent kinases (CDKs and by their counter-acting phosphatases. Activation of the Cdk1:Cyclin B complex during mitotic entry is controlled by the Wee1/Myt1 inhibitory kinases and by Cdc25 activatory phosphatase, which are themselves regulated by Cdk1:Cyclin B within two positive circuits. Impairing these two feedbacks with chemical inhibitors induces a transient entry into M phase referred to as mitotic collapse. The pathology of mitotic collapse reveals that the positive circuits play a significant role in maintaining the M phase state. To better understand the function of these feedback loops during G2/M transition, we propose a simple model for mitotic entry in mammalian cells including spatial control over Greatwall kinase phosphorylation. After parameter calibration, the model is able to recapture the complex and non-intuitive molecular dynamics reported by Potapova et al. (Potapova et al., 2011. Moreover, it predicts the temporal patterns of other mitotic regulators which have not yet been experimentally tested and suggests a general design principle of cell cycle control: latching switches buffer the cellular stresses which accompany cell cycle processes to ensure that the transitions are smooth and robust.

Robust mitotic entry is ensured by a latching switch.

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Tuck, Chloe; Zhang, Tongli; Potapova, Tamara; Malumbres, Marcos; Novák, Béla

2013-01-01

Cell cycle events are driven by Cyclin dependent kinases (CDKs) and by their counter-acting phosphatases. Activation of the Cdk1:Cyclin B complex during mitotic entry is controlled by the Wee1/Myt1 inhibitory kinases and by Cdc25 activatory phosphatase, which are themselves regulated by Cdk1:Cyclin B within two positive circuits. Impairing these two feedbacks with chemical inhibitors induces a transient entry into M phase referred to as mitotic collapse. The pathology of mitotic collapse reveals that the positive circuits play a significant role in maintaining the M phase state. To better understand the function of these feedback loops during G2/M transition, we propose a simple model for mitotic entry in mammalian cells including spatial control over Greatwall kinase phosphorylation. After parameter calibration, the model is able to recapture the complex and non-intuitive molecular dynamics reported by Potapova et al. (Potapova et al., 2011). Moreover, it predicts the temporal patterns of other mitotic regulators which have not yet been experimentally tested and suggests a general design principle of cell cycle control: latching switches buffer the cellular stresses which accompany cell cycle processes to ensure that the transitions are smooth and robust.

Metformin protects rat hepatocytes against bile acid-induced apoptosis.

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Titia E Woudenberg-Vrenken

Full Text Available BACKGROUND: Metformin is used in the treatment of Diabetes Mellitus type II and improves liver function in patients with non-alcoholic fatty liver disease (NAFLD. Metformin activates AMP-activated protein kinase (AMPK, the cellular energy sensor that is sensitive to changes in the AMP/ATP-ratio. AMPK is an inhibitor of mammalian target of rapamycin (mTOR. Both AMPK and mTOR are able to modulate cell death. AIM: To evaluate the effects of metformin on hepatocyte cell death. METHODS: Apoptotic cell death was induced in primary rat hepatocytes using either the bile acid glycochenodeoxycholic acid (GCDCA or TNFα in combination with actinomycin D (actD. AMPK, mTOR and phosphoinositide-3 kinase (PI3K/Akt were inhibited using pharmacological inhibitors. Apoptosis and necrosis were quantified by caspase activation, acridine orange staining and Sytox green staining respectively. RESULTS: Metformin dose-dependently reduces GCDCA-induced apoptosis, even when added 2 hours after GCDCA, without increasing necrotic cell death. Metformin does not protect against TNFα/ActD-induced apoptosis. The protective effect of metformin is dependent on an intact PI3-kinase/Akt pathway, but does not require AMPK/mTOR-signaling. Metformin does not inhibit NF-κB activation. CONCLUSION: Metformin protects against bile acid-induced apoptosis and could be considered in the treatment of chronic liver diseases accompanied by inflammation.

X-ray- and TEM-induced mitotic recombination in Drosophila melanogaster: Unequal and sister-strand recombination

International Nuclear Information System (INIS)

Becker, H.J.

1975-01-01

Twin mosaic spots of dark-apricot and light-apricot ommatidia were found in the eyes of wsup(a)/wsup(a) females, of wsup(a) males, of females homozygous for In(1)sc 4 , wsup(a) and of attached-X females homozygous for wsup(a). The flies were raised from larvae which had been treated with 1,630 R of X-rays at the age of 48-52 hours. An additional group of wsup(a)/wsup(a) females and wsup(a) males came from larvae that had been fed with triethylene melamine (TEM) at the age of 22-24 hours. The twin spots apparently were the result of induced unequal mitotic recombination, i.e. from unequal sister-strand recombination in the males and from unequal sister-strand recombination as well as, possibly, unequal recombination between homologous strands in the females. That is, a duplication resulted in wsup(a)Dpwsup(a)/wsup(a) dark-apricto ommatidia and the corresponding deficiency in an adjacent area of wsup(a)/Dfwsup(a) light-apricot ommatidia. In an additional experiment sister-strand mitotic recombination in the ring-X chromosome of ring-X/rod-X females heterozygous for w and wsup(co) is believed to be the cause for X-ray induced single mosaic spots that show the phenotype of the rod-X marker. (orig.) [de

DHX15 is associated with poor prognosis in acute myeloid leukemia (AML) and regulates cell apoptosis via the NF-kB signaling pathway.

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Pan, Lili; Li, Yang; Zhang, Hai-Ying; Zheng, Yi; Liu, Xiao-Li; Hu, Zheng; Wang, Yi; Wang, Jing; Cai, Yuan-Hua; Liu, Qiao; Chen, Wan-Ling; Guo, Ying; Huang, Yuan-Mao; Qian, Feng; Jin, Li; Wang, Jiucun; Wang, Shao-Yuan

2017-10-27

The role of DHX15 , a newly identified DEAH-box RNA helicase, in leukemogenesis remains elusive. Here, we identified a recurrent mutation in DHX15 (NM_001358:c.664C>G: p.(R222G)) in one familial AML patient and 4/240 sporadic AML patients. Additionally, DHX15 was commonly overexpressed in AML patients and associated with poor overall survival (OS) (P=0.019) and relapse-free survival (RFS) (P=0.032). In addition, we found a distinct expression pattern of DHX15 . DHX15 was highly expressed in hematopoietic stem cells and leukemia cells but was lowly expressed in mature blood cells. DHX15 was down-regulated when AML patients achieved disease remission or when leukemia cell lines were induced to differentiate. DHX15 silencing greatly inhibited leukemia cell proliferation and induced cell apoptosis and G1-phase arrest. In contrast, the restoration of DHX15 expression rescued cell viability and reduced cell apoptosis. In addition, we found that DHX15 was down-regulated when cell apoptosis was induced by ATO (arsenic trioxide); overexpression of DHX15 caused dramatic resistance to ATO-induced cell apoptosis, suggesting an important role for DHX15 in cell apoptosis. We further explored the mechanism of DHX15 in apoptosis and found that overexpression of DHX15 activated NF-kB transcription. Knockdown of DHX15 inhibited the nuclear translocation and activation of the NF-kB subunit P65 in leukemia cells. Several downstream targets of the NF-kB pathway were also down-regulated, and apoptosis-associated genes CASP3 and PARP were activated. In conclusion, this study represents the first demonstration that DHX15 plays an important role in leukemogenesis via the NF-kB signaling pathway and may serve as an independent prognostic marker for AML.

Physcion induces mitochondria-driven apoptosis in colorectal cancer cells via downregulating EMMPRIN.

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Chen, Xuehong; Gao, Hui; Han, Yantao; Ye, Junli; Xie, Jing; Wang, Chunbo

2015-10-05

Physcion, an anthraquinone derivative widely isolated and characterized from both terrestrial and marine sources, has anti-tumor effects on a variety of carcinoma cells, mainly through inhibition of cell proliferation, apoptosis induction and cell cycle arrest. However, little is known about the mechanisms underlying its role in tumor progression. In the present study, we investigated the molecular mechanisms involved in physcion-induced apoptosis in human colorectal cancer (CRC) lines HCT116. Our results showed that physcion inhibited tumor cell viability in a dose- and time-dependent manner, and induced cell apoptosis via intrinsic mitochondrial pathway. Our results also revealed that physcion treatment significantly inhibited extracelluar matrix metalloproteinase inducer (EMMPRIN) expression in HCT116 cells in a dose-dependent manner and overexpression of EMMPRIN protein markedly reduced physcion-induced cell apoptosis. Furthermore, our results strongly indicated the modulating effect of physcion on EMMPRIN is correlated with AMP-activated protein kinase (AMPK)/Hypoxia-inducible factor 1α (HIF-1α) signaling pathway. Our data provide the first experimental evidence that physcion induces mitochondrial apoptosis in CRC cells by downregulating of EMMPRIN via AMPK/HIF-1α signaling pathway and suggest a new mechanism to explain its anti-tumor effects. Copyright © 2015 Elsevier B.V. All rights reserved.

Radiation induced asymmetries in mitotic recombination: evidence for a directional bias in the formation of asymmetric hybrid DNA in yeast

International Nuclear Information System (INIS)

Friedman, L.R.; Sobell, H.M.

We have examined radiation-induced mitotic recombination using two alleles (his1-36, his1-49) in the his1 gene. When the haploid containing his1-36 is irradiated with varying doses of γ rays and then mated with the unirradiated strain containing his1-49, analyses of the selected prototrophs show them to be primarily + +/+ 49. If, on the other hand, the haploid strain containing his1-49 is the irradiated parent, the prototrophic diploids are primarily + +/36 +. In control experiments, where either both strains are irradiated or not irradiated, no such asymmetries are found. These data indicate that the irradiated haploid chromosome tends to be the recipient of genetic information. We interpret these results as indicating a directional bias in the formation of hybrid DNA in radiation-induced mitotic recombination, and discuss these results in terms of current models of genetic recombination

Development of an arsenic trioxide vapor and arsine sampling train

International Nuclear Information System (INIS)

Crecelius, E.A.; Sanders, R.W.

1980-01-01

A sampling train was evaluated using 76 As tracer for the measurement of particulate arsenic, arsine, and arsenic trioxide vapor in air and industrial process gas streams. In this train, a demister was used to remove droplets of water and oil, and particulates were removed by a filter. Vapor arsenic trioxide was collected in an impinger solution, and arsine gas was collected on silvered quartz beads. Hydrogen sulfide gas did not reduce the arsine trapping efficiency of the silvered beads, and charcoal proved to be an effective trap for both arsine and arsenic trioxide vapor. 1 figure, 2 tables

Arsenic-induced alteration in intracellular calcium homeostasis induces head kidney macrophage apoptosis involving the activation of calpain-2 and ERK in Clarias batrachus

International Nuclear Information System (INIS)

Banerjee, Chaitali; Goswami, Ramansu; Datta, Soma; Rajagopal, R.; Mazumder, Shibnath

2011-01-01

We had earlier shown that exposure to arsenic (0.50 μM) caused caspase-3 mediated head kidney macrophage (HKM) apoptosis involving the p38-JNK pathway in Clarias batrachus. Here we examined the roles of calcium (Ca 2+ ) and extra-cellular signal-regulated protein kinase (ERK), the other member of MAPK-pathway on arsenic-induced HKM apoptosis. Arsenic-induced HKM apoptosis involved increased expression of ERK and calpain-2. Nifedipine, verapamil and EGTA pre-treatment inhibited the activation of calpain-2, ERK and reduced arsenic-induced HKM apoptosis as evidenced from reduced caspase-3 activity, Annexin V-FITC-propidium iodide and Hoechst 33342 staining. Pre-incubation with ERK inhibitor U 0126 inhibited the activation of calpain-2 and interfered with arsenic-induced HKM apoptosis. Additionally, pre-incubation with calpain-2 inhibitor also interfered with the activation of ERK and inhibited arsenic-induced HKM apoptosis. The NADPH oxidase inhibitor apocynin and diphenyleneiodonium chloride also inhibited ERK activation indicating activation of ERK in arsenic-exposed HKM also depends on signals from NADPH oxidase pathway. Our study demonstrates the critical role of Ca 2+ homeostasis on arsenic-induced HKM apoptosis. We suggest that arsenic-induced alteration in intracellular Ca 2+ levels initiates pro-apoptotic ERK and calpain-2; the two pathways influence each other positively and induce caspase-3 mediated HKM apoptosis. Besides, our study also indicates the role of ROS in the activation of ERK pathway in arsenic-induced HKM apoptosis in C. batrachus. - Highlights: → Altered Ca 2+ homeostasis leads to arsenic-induced HKM apoptosis. → Calpain-2 plays a critical role in the process. → ERK is pro-apoptotic in arsenic-induced HKM apoptosis. → Arsenic-induced HKM apoptosis involves cross talk between calpain-2 and ERK.

Radiation-induced apoptosis in different pH environments in vitro

International Nuclear Information System (INIS)

Lee, Hyung-Sik; Park, Heon J.; Lyons, John C.; Griffin, Robert J.; Auger, Elizabeth A.; Song, Chang W.

1997-01-01

Purpose: The effect of environmental pH on the radiation-induced apoptosis in tumor cells in vitro was investigated. Methods and Materials: Mammary adenocarcinoma cells of A/J mice (SCK cells) were irradiated with γ-rays using a 137 Cs irradiator and incubated in media of different pHs. After incubation at 37 deg. C for 24-120 h the extent of apoptosis was determined using agarose gel electrophoresis, TdT-mediated dUTP-biotin nick end labeling (TUNEL) staining, flow cytometry, and release of 3 H from 3 H-thymidine labeled cells. The clonogenicity of the cells irradiated in different pH medium was determined, and the progression of cells through the cell cycle after irradiation in different pHs was also determined with flow cytometry. Results: Irradiation with 2-12 Gy of γ-rays induced apoptosis in SCK cells in pH 7.5 medium within 48 h as judged from the results of four different assays mentioned. Radiation-induced apoptosis declined as the medium pH was lowered from 7.5 to 6.4. Specifically, the radiation-induced degradation of DNA including the early DNA breaks, as determined with the TUNEL method, progressively declined as the medium pH was lowered so that little DNA fragmentation occurred 48 h after irradiation with 12 Gy in pH 6.6 medium. When the cells were irradiated and incubated for 48 h in pH 6.6 medium and the medium was replaced with pH 7.5 medium, DNA fragmentation promptly occurred. DNA fragmentation also occurred even in pH 6.6 medium when the cells were irradiated and maintained in pH 7.5 medium for 8 h or longer post-irradiation before incubation in pH 6.6 medium. The radiation-induced G 2 arrest in pH 6.6 medium lasted markedly longer than that in pH 7.5 medium. Conclusion: Radiation-induced apoptosis in SCK cells in vitro is reversibly suppressed in an acidic environment. Taking the results of four different assays together, it was concluded that early step(s) in the apoptotic pathway, probably the DNA break or upstream of DNA break, is

Comparative study on 4 quantitative detection methods of apoptosis induced by radiation

International Nuclear Information System (INIS)

Yang Yepeng; Chen Guanying; Zhou Mei; Shen Qinjian; Shen Lei; Zhu Yingbao

2004-01-01

Objective: To reveal the capability of 4 apoptosis-detecting methods to discriminate between apoptosis and necrosis and show their respective advantages and shortcomings through comparison of detected results and analysis of detection mechanism. Methods: Four methods, PI staining-flow cytometric detection (P-F method), TUNEL labeling-flow cytometric detection (T-F method), annexing V-FITC/PI vital staining-flow cytometric detection (A-F method) and Hoechst/PI vital staining-fluorescence microscopic observation (H-O method), were used to determine apoptosis and necrosis in human breast cancer MCF-7 cell line induced by γ-rays. Hydroxycamptothecine and sodium azide were used to induce positive controls of apoptosis and necrosis respectively. Results: All 4 methods showed good time-dependent and dose dependent respondence to apoptosis induced by γ-rays and hydroxycamptothecine. Apoptotic cell ratios and curve slopes obtained from P-F method were minimum and, on the contrary, those from T-F method were maximum among these 4 methods. With A-F method and H-O method, two sets of data, apoptosis and necrosis, could be gained respectively and the data gained from these two methods were close to equal. A-F method and H-O method could distinguish necrosis induced by sodium azide from apoptosis while P-F method and T-F method presented false increase of apoptosis. Conclusions: P-F method and T-F method can not discriminate between apoptosis and necrosis. P-F method is less sensitive but more simple, convenient and economical than T-F method. A-F method and H-O method can distinguish necrosis from apoptosis. A-F method is more costly but more quick and reliable than H-O method. H-O method is economical, practical and morphological changes of cells and nucleus can be observed simultaneously with it. (authors)

Aspirin Induces Apoptosis through Release of Cytochrome c from Mitochondria

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Katja C. Zimmermann

2000-01-01

Full Text Available Nonsteroidal anti-inflammatory drugs (NSAID reduce the risk for cancer, due to their anti proliferative and apoptosis-inducing effects. A critical pathway for apoptosis involves the release of cytochrome c from mitochondria, which then interacts with Apaf-1 to activate caspase proteases that orchestrate cell death. In this study we found that treatment of a human cancer cell line with aspirin induced caspase activation and the apoptotic cell morphology, which was blocked by the caspase inhibitor zVAD-fmk. Further analysis of the mechanism underlying this apoptotic event showed that aspirin induces translocation of Bax to the mitochondria and triggers release of cytochrome c into the cytosol. The release of cytochrome c from mitochondria was inhibited by overexpression of the antiapoptotic protein Bcl-2 and cells that lack Apaf-1 were resistant to aspirin-induced apoptosis. These data provide evidence that the release of cytochrome c is an important part of the apoptotic mechanism of aspirin.

Effects of ceramide inhibition on radiation-induced apoptosis in human leukemia MOLT-4 cells

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Takahashi, Eriko; Inanami, Osamu; Asanuma, Taketoshi; Kuwabara, Mikinori [Hokkaido Univ., Graduate School of Veterinary Medicine, Sapporo, Hokkaido (Japan)

2006-03-15

In the present study, using inhibitors of ceramide synthase (fumonisin B{sub 1}), ketosphinganine synthetase (L-cycloserine), acid sphingomyelinase (D609 and desipramine) and neutral sphingomyelinase (GW4869), the role of ceramide in X-ray-induced apoptosis was investigated in MOLT-4 cells. The diacylglycerol kinase (DGK) assay showed that the intracellular concentration of ceramide increased time-dependently after X irradiation of cells, and this radiation-induced accumulation of ceramide did not occur prior to the appearance of apoptotic cells. Treatment with D609 significantly inhibited radiation-induced apoptosis, but did not inhibit the increase of intracellular ceramide. Treatment with desipramine or GW4869 prevented neither radiation-induced apoptosis nor the induced increase of ceramide. On the other hand, fumonisin B{sub 1} and L-cycloserine had no effect on the radiation-induced induction of apoptosis, in spite of significant inhibition of the radiation-induced ceramide. From these results, it was suggested that the increase of the intracellular concentration of ceramide was not essential for radiation-induced apoptosis in MOLT-4 cells. (author)

Effects of ceramide inhibition on radiation-induced apoptosis in human leukemia MOLT-4 cells

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Takahashi, Eriko; Inanami, Osamu; Asanuma, Taketoshi; Kuwabara, Mikinori

2006-01-01

In the present study, using inhibitors of ceramide synthase (fumonisin B 1 ), ketosphinganine synthetase (L-cycloserine), acid sphingomyelinase (D609 and desipramine) and neutral sphingomyelinase (GW4869), the role of ceramide in X-ray-induced apoptosis was investigated in MOLT-4 cells. The diacylglycerol kinase (DGK) assay showed that the intracellular concentration of ceramide increased time-dependently after X irradiation of cells, and this radiation-induced accumulation of ceramide did not occur prior to the appearance of apoptotic cells. Treatment with D609 significantly inhibited radiation-induced apoptosis, but did not inhibit the increase of intracellular ceramide. Treatment with desipramine or GW4869 prevented neither radiation-induced apoptosis nor the induced increase of ceramide. On the other hand, fumonisin B 1 and L-cycloserine had no effect on the radiation-induced induction of apoptosis, in spite of significant inhibition of the radiation-induced ceramide. From these results, it was suggested that the increase of the intracellular concentration of ceramide was not essential for radiation-induced apoptosis in MOLT-4 cells. (author)

Study of progesterone mechanisms in radio-induced apoptosis prevention

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Vares, G.

2004-10-01

The purpose of this work was to study the modulation of radiation-induced cell death of human mammary tumoral cells by progesterone. On the one hand, we observed that progesterone protects cells against radiation-induced apoptosis and increases the proportion of surviving and proliferating damaged cells. On the other hand, a transcriptome analysis was undertaken in irradiated cells treated by progesterone, using DNA micro-arrays. This let us highlight several transcriptional dis-regulations that are likely to explain the protective effect of the hormone; in particular, we showed that progesterone regulates the expression of genes implicated in apoptosis signaling by death receptors. Knowing the crucial role of hormonal control and of apoptosis regulation in breast cancer initiation, our results may help to achieve a better understanding of the implication of progesterone in mammary carcinogenesis. (author)

Cathepsin B is involved in the heat shock induced cardiomyocytes apoptosis as well as the anti-apoptosis effect of HSP-70.

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Hsu, Shu-Fen; Hsu, Chuan-Chih; Cheng, Bor-Chih; Lin, Cheng-Hsien

2014-11-01

Cathepsin B is one of the major lysosomal cysteine proteases that plays an important role in apoptosis. Herein, we investigated whether Cathepsin B is involved in cardiomyocyte apoptosis caused by hyperthermic injury (HI) and heat shock protein (HSP)-70 protects these cells from HI-induced apoptosis mediated by Cathepsin. HI was produced in H9C2 cells by putting them in a circulating 43 °C water bath for 120 min, whereas preinduction of HSP-70 was produced in H9C2 cells by mild heat preconditioning (or putting them in 42 °C water bath for 30 min) 8 h before the start of HI. It was found that HI caused both cardiomyocyte apoptosis and increased Cathepsin B activity in H9C2 cells. E-64-c, in addition to reducing Cathepsin B activity, significantly attenuated HI-induced cardiomyocyte apoptosis (evidenced by increased apoptotic cell numbers, increased tuncated Bid (t-Bid), increased cytochrome C, increased caspase-9/-3, and decreased Bcl-2/Bax) in H9C2 cells. In addition, preinduction of HSP-70 by mild heat preconditioning or inhibition of HSP-70 by Tripolide significantly attenuated or exacerbated respectively both the cardiomyocyte apoptosis and increased Cathepsin B activity in H9C2 cells. Furthermore, the beneficial effects of pre-induction of HSP-70 by mild heat production in reducing both cardiomyocyte apoptosis and increased Cathepsin B activity caused by HI can be significantly reduced by Triptolide preconditioning. These results indicate that Cathepsin B is involved in HI-induced cardiomyocyte apoptosis in H9C2 cells and HSP-70 protects these cells from HI-induced cardiomyocyte apoptosis through Cathepsin B pathways.

Isolation and identification of gene mediating radiation-induced apoptosis in human leukemia U937 cells

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Tong Xin; Luo Ying; Dong Yan; Sun Zhixian

1998-01-01

Objective: Increasing evidences suggest that Caspase family proteases play an important role in the effector mechanism of apoptotic cell death. Radiation (IR) can induce apoptosis in tumor cells, so it is very important to isolate and identify the member of the Caspase family proteases involved in IR-induced apoptosis, and this would contribute to the understanding of the mechanism responsible for apoptosis execution. Methods: A PCR approach to isolate genes for IR-induced apoptosis was developed. The approach used degenerated oligonucleotide encoding the highly conserved peptides that were present in all known Caspases. Results: Protease inhibitors special for Caspases could block the apoptotic cell death caused by IR, and Caspase-3 was isolated from irradiated human leukemia U937 cells. Conclusion: Caspases involve in IR-induced apoptosis, and Caspase-3 is the pivotal element of IR-induced apoptosis

CD36 Mediated Fatty Acid-Induced Podocyte Apoptosis via Oxidative Stress.

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Wei Hua

Full Text Available Hyperlipidemia-induced apoptosis mediated by fatty acid translocase CD36 is associated with increased uptake of ox-LDL or fatty acid in macrophages, hepatocytes and proximal tubular epithelial cells, leading to atherosclerosis, liver damage and fibrosis in obese patients, and diabetic nephropathy (DN, respectively. However, the specific role of CD36 in podocyte apoptosis in DN with hyperlipidemia remains poorly investigated.The expression of CD36 was measured in paraffin-embedded kidney tissue samples (Ctr = 18, DN = 20 by immunohistochemistry and immunofluorescence staining. We cultured conditionally immortalized mouse podocytes (MPC5 and treated cells with palmitic acid, and measured CD36 expression by real-time PCR, Western blot analysis and immunofluorescence; lipid uptake by Oil red O staining and BODIPY staining; apoptosis by flow cytometry assay, TUNEL assay and Western blot analysis; and ROS production by DCFH-DA fluorescence staining. All statistical analyses were performed using SPSS 21.0 statistical software.CD36 expression was increased in kidney tissue from DN patients with hyperlipidemia. Palmitic acid upregulated CD36 expression and promoted its translocation from cytoplasm to plasma membrane in podocytes. Furthermore, palmitic acid increased lipid uptake, ROS production and apoptosis in podocytes, Sulfo-N-succinimidyloleate (SSO, the specific inhibitor of the fatty acid binding site on CD36, decreased palmitic acid-induced fatty acid accumulation, ROS production, and apoptosis in podocytes. Antioxidant 4-hydroxy-2,2,6,6- tetramethylpiperidine -1-oxyl (tempol inhibited the overproduction of ROS and apoptosis in podocytes induced by palmitic acid.CD36 mediated fatty acid-induced podocyte apoptosis via oxidative stress might participate in the process of DN.

Fast neutrons-induced apoptosis is Fas-independent in lymphoblastoid cells

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Fischer, Barbara; Benzina, Sami; Jeannequin, Pierre; Dufour, Patrick; Bergerat, Jean-Pierre; Denis, Jean-Marc; Gueulette, John; Bischoff, Pierre L.

2005-01-01

We have previously shown that ionizing radiation-induced apoptosis in human lymphoblastoid cells differs according to their p53 status, and that caspase 8-mediated cleavage of BID is involved in the p53-dependent pathway. In the present study, we investigated the role of Fas signaling in caspase 8 activation induced by fast neutrons irradiation in these cells. Fas and FasL expression was assessed by flow cytometry and by immunoblot. We also measured Fas aggregation after irradiation by fluorescence microscopy. We found a decrease of Fas expression after irradiation, but no change in Fas ligand expression. We also showed that, in contrast to the stimulation of Fas by an agonistic antibody, Fas aggregation did not occur after irradiation. Altogether, our data strongly suggest that fast neutrons induced-apoptosis is Fas-independent, even in p53-dependent apoptosis

Sumoylation of the Tumor Suppressor Promyelocytic Leukemia Protein Regulates Arsenic Trioxide-Induced Collagen Synthesis in Osteoblasts.

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Xu, Wen-Xiao; Liu, Sheng-Zhi; Wu, Di; Qiao, Guo-Fen; Yan, Jinglong

2015-01-01

Promyelocytic leukemia (PML) protein is a tumor suppressor that fuses with retinoic acid receptor-α (PML-RARα) to contribute to the initiation of acute promyelocytic leukemia (APL). Arsenic trioxide (ATO) upregulates expression of TGF-β1, promoting collagen synthesis in osteoblasts, and ATO binds directly to PML to induce oligomerization, sumoylation, and ubiquitination. However, how ATO upregulates TGF-β1 expression is uncertain. Thus, we suggested that PML sumoylation is responsible for regulation of TGF-β1 protein expression. Kunming mice were treated with ATO, and osteoblasts were counted under scanning electron microscopy. Masson's staining was used to quantify collagen content. hFOB1.19 cells were transfected with siRNA against UBC9 or RNF4, and then treated with ATO or FBS. TGF-β1, PML expression, and sumoylation were quantified with Western blot, and collagen quantified via immunocytochemistry. ATO enhanced osteoblast accumulation, collagen synthesis, and PML-NB formation in vivo. Knocking down UBC9 in hFOB1.19 cells inhibited ATO- and FBS-induced PML sumoylation, TGF-β1 expression, and collagen synthesis. Conversely, knocking down RNF4 enhanced ATO- and FBS-induced PML sumoylation, TGF-β1 expression, and collagen synthesis. These data suggest that PML sumoylation is required for ATO-induced collagen synthesis in osteoblasts. © 2015 S. Karger AG, Basel.

Curcumin induces apoptosis of upper aerodigestive tract cancer cells by targeting multiple pathways.

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A R M Ruhul Amin

Full Text Available Curcumin, a natural compound isolated from the Indian spice "Haldi" or "curry powder", has been used for centuries as a traditional remedy for many ailments. Recently, the potential use of curcumin in cancer prevention and therapy urges studies to uncover the molecular mechanisms associated with its anti-tumor effects. In the current manuscript, we investigated the mechanism of curcumin-induced apoptosis in upper aerodigestive tract cancer cell lines and showed that curcumin-induced apoptosis is mediated by the modulation of multiple pathways such as induction of p73, and inhibition of p-AKT and Bcl-2. Treatment of cells with curcumin induced both p53 and the related protein p73 in head and neck and lung cancer cell lines. Inactivation of p73 by dominant negative p73 significantly protected cells from curcumin-induced apoptosis, whereas ablation of p53 by shRNA had no effect. Curcumin treatment also strongly inhibited p-AKT and Bcl-2 and overexpression of constitutively active AKT or Bcl-2 significantly inhibited curcumin-induced apoptosis. Taken together, our findings suggest that curcumin-induced apoptosis is mediated via activating tumor suppressor p73 and inhibiting p-AKT and Bcl-2.

Effect of uvs1, uvs2 and xrs mutations on the radiosensitivity and the induced mitotic recombination frequency in diploid yeast cells

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Suslova, N.G.; Fedorova, I.V.; Zheleznyakova, N.Yu.

1975-01-01

The influence of the loci of radiosensitivity uvs1, uvs2, and xrs in the homozygous state at the diploid level on the sensitivity to UV and ionizing radiation and induced mitotic recombination was studied in the yeast Sacch. cerevisiae. Hypersensitivity to UV irradiation was detected in the diploids uvs2 uvs2 xrs xrs in comparision with the corresponding control. The diploid uvs1 uvs1 uvs2 uvs2 does not differ in UV sensitivity from the diploid uvs1 uvs1 UVS2 UVS2. These facts demonstrate that the uvs1 and uvs2 mutations, on the one hand, and the xrs mutations, on the other, normally control different pathways of elimination of UV-induced damages. It was shown that the diploid uvs2 uvs2 xrs3 xrs3 is far more sensitive to the lethal action of x rays than the control diploid UVS2 UVS2 xrs3 xrs3. Consequently, the mutations uvs2 and xrs3 block different modes of repair of damages induced by ionizing radiation. In all the double-mutant diploids, the frequency of mitotic recombination induced by UV rays increases sharply in comparison with that of the radioresistant diploids UVS UVS XRS XRS and the UV-sensitive diploids uvs2 uvs2 XRS XRS. Possible causes of the observed phenomenon are discussed. It was established that in a diploid homozygous for the loci uvs2 xrs5, the frequency of mitotic recombination induced by x rays increases extremely sharply. This fact confirms the hypothesis that the gene product of the locus uvs2 participates in the repair of DNA after the action of ionizing radiation. (author)

Effect of cycloheximide and actinomycin D on radionuclide 235U-induced apoptosis

International Nuclear Information System (INIS)

Fu Qiang; Zhang Lansheng; Zhu Shoupeng

1999-01-01

Objective: The mechanism of apoptosis induced by radionuclide 235 U was studied. Methods: MTT and JAM assay were used to analyse the cell viability and quantification of fragmented DNA. Results: The inhibitor of protein cycloheximide (CHX), and the inhibitor of RNA synthesis, actinomycin D. cannot inhibit the apoptosis induced by 235 U, but CHX can partly inhibit apoptotic cells DNA fragmentation. Conclusion: The pathway of apoptosis induced by radionuclide 235 U is different from X-and γ-ray external irradiation, protein synthesis is not essential for it, but synthetic endonuclease is necessary for DNA fragmentation of apoptotic cells

DNA damage-inducible transcript 4 (DDIT4) mediates methamphetamine-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes

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Chen, Rui; Wang, Bin; Chen, Ling; Cai, Dunpeng; Li, Bing; Chen, Chuanxiang; Huang, Enping; Liu, Chao; Lin, Zhoumeng; Xie, Wei-Bing; Wang, Huijun

2016-01-01

Methamphetamine (METH) is an amphetamine-like psychostimulant that is commonly abused. Previous studies have shown that METH can induce damages to the nervous system and recent studies suggest that METH can also cause adverse and potentially lethal effects on the cardiovascular system. Recently, we demonstrated that DNA damage-inducible transcript 4 (DDIT4) regulates METH-induced neurotoxicity. However, the role of DDIT4 in METH-induced cardiotoxicity remains unknown. We hypothesized that DDIT4 may mediate METH-induced autophagy and apoptosis in cardiomyocytes. To test the hypothesis, we examined DDIT4 protein expression in cardiomyocytes and in heart tissues of rats exposed to METH with Western blotting. We also determined the effects on METH-induced autophagy and apoptosis after silencing DDIT4 expression with synthetic siRNA with or without pretreatment of a mTOR inhibitor rapamycin in cardiomyocytes using Western blot analysis, fluorescence microscopy and TUNEL staining. Our results showed that METH exposure increased DDIT4 expression and decreased phosphorylation of mTOR that was accompanied with increased autophagy and apoptosis both in vitro and in vivo. These effects were normalized after silencing DDIT4. On the other hand, rapamycin promoted METH-induced autophagy and apoptosis in DDIT4 knockdown cardiomyocytes. These results suggest that DDIT4 mediates METH-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes. - Highlights: • METH exposure increases DDIT4 expression in cardiomyocytes. • DDIT4 mediates METH-induced autophagy and apoptosis in cardiomyocytes. • DDIT4 silencing protects cardiomyocytes against METH-caused autophagy and apoptosis.

DNA damage-inducible transcript 4 (DDIT4) mediates methamphetamine-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes

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Chen, Rui [Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou 510515 (China); Department of Forensic Medicine, Guangdong Medical University, Dongguan 523808 (China); Wang, Bin; Chen, Ling; Cai, Dunpeng; Li, Bing; Chen, Chuanxiang; Huang, Enping [Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou 510515 (China); Liu, Chao [Guangzhou Forensic Science Institute, Guangzhou 510030 (China); Lin, Zhoumeng [Institute of Computational Comparative Medicine and Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506 (United States); Xie, Wei-Bing, E-mail: xieweib@126.com [Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou 510515 (China); Wang, Huijun, E-mail: hjwang711@yahoo.cn [Department of Forensic Medicine, School of Basic Medical Science, Southern Medical University, Guangzhou 510515 (China)

2016-03-15

Methamphetamine (METH) is an amphetamine-like psychostimulant that is commonly abused. Previous studies have shown that METH can induce damages to the nervous system and recent studies suggest that METH can also cause adverse and potentially lethal effects on the cardiovascular system. Recently, we demonstrated that DNA damage-inducible transcript 4 (DDIT4) regulates METH-induced neurotoxicity. However, the role of DDIT4 in METH-induced cardiotoxicity remains unknown. We hypothesized that DDIT4 may mediate METH-induced autophagy and apoptosis in cardiomyocytes. To test the hypothesis, we examined DDIT4 protein expression in cardiomyocytes and in heart tissues of rats exposed to METH with Western blotting. We also determined the effects on METH-induced autophagy and apoptosis after silencing DDIT4 expression with synthetic siRNA with or without pretreatment of a mTOR inhibitor rapamycin in cardiomyocytes using Western blot analysis, fluorescence microscopy and TUNEL staining. Our results showed that METH exposure increased DDIT4 expression and decreased phosphorylation of mTOR that was accompanied with increased autophagy and apoptosis both in vitro and in vivo. These effects were normalized after silencing DDIT4. On the other hand, rapamycin promoted METH-induced autophagy and apoptosis in DDIT4 knockdown cardiomyocytes. These results suggest that DDIT4 mediates METH-induced autophagy and apoptosis through mTOR signaling pathway in cardiomyocytes. - Highlights: • METH exposure increases DDIT4 expression in cardiomyocytes. • DDIT4 mediates METH-induced autophagy and apoptosis in cardiomyocytes. • DDIT4 silencing protects cardiomyocytes against METH-caused autophagy and apoptosis.

Atrazine-induced apoptosis of splenocytes in BALB/C mice

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Zheng Jing

2011-10-01

Full Text Available Abstract Background Atrazine (2-chloro-4-ethytlamino-6-isopropylamine-1,3,5-triazine; ATR, is the most commonly applied broad-spectrum herbicide in the world. Unintentional overspray of ATR poses an immune function health hazard. The biomolecular mechanisms responsible for ATR-induced immunotoxicity, however, are little understood. This study presents on our investigation into the apoptosis of splenocytes in mice exposed to ATR as we explore possible immunotoxic mechanisms. Methods Oral doses of ATR were administered to BALB/C mice for 21 days. The histopathology, lymphocyte apoptosis and the expression of apoptosis-related proteins from the Fas/Fas ligand (FasL apoptotic pathway were examined from spleen samples. Results Mice administered ATR exhibited a significant decrease in spleen and thymus weight. Electron microscope histology of ultrathin sections of spleen revealed degenerative micromorphology indicative of apoptosis of splenocytes. Flow cytometry revealed that the percentage of apoptotic lymphocytes increased in a dose-dependent manner after ATR treatment. Western blots identified increased expression of Fas, FasL and active caspase-3 proteins in the treatment groups. Conclusions ATR is capable of inducing splenocytic apoptosis mediated by the Fas/FasL pathway in mice, which could be the potential mechanism underlying the immunotoxicity of ATR.

Statins induce apoptosis in rat and human myotube cultures by inhibiting protein geranylgeranylation but not ubiquinone

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Johnson, Timothy E.; Zhang, Xiaohua; Bleicher, Kimberly B.; Dysart, Gary; Loughlin, Amy F.; Schaefer, William H.; Umbenhauer, Diane R.

2004-01-01

Statins are widely used to treat lipid disorders. These drugs are safe and well tolerated; however, in <1% of patients, myopathy and/or rhabdomyolysis can develop. To better understand the mechanism of statin-induced myopathy, we examined the ability of structurally distinct statins to induce apoptosis in an optimized rat myotube model. Compound A (a lactone) and Cerivastatin (an open acid) induced apoptosis, as measured by TUNEL and active caspase 3 staining, in a concentration- and time-dependent manner. In contrast, an epimer of Compound A (Compound B) exhibited a much weaker apoptotic response. Statin-induced apoptosis was completely prevented by mevalonate or geranylgeraniol, but not by farnesol. Zaragozic acid A, a squalene synthase inhibitor, caused no apoptosis on its own and had no effect on Compound-A-induced myotoxicity, suggesting the apoptosis was not a result of cholesterol synthesis inhibition. The geranylgeranyl transferase inhibitors GGTI-2133 and GGTI-2147 caused apoptosis in myotubes; the farnesyl transferase inhibitor FTI-277 exhibited a much weaker effect. In addition, the prenylation of rap1a, a geranylgeranylated protein, was inhibited by Compound A in myotubes at concentrations that induced apoptosis. A similar statin-induced apoptosis profile was seen in human myotube cultures but primary rat hepatocytes were about 200-fold more resistant to statin-induced apoptosis. Although the statin-induced hepatotoxicity could be attenuated with mevalonate, no effect was found with either geranylgeraniol or farnesol. In studies assessing ubiquinone levels after statin treatment in rat and human myotubes, there was no correlation between ubiquinone levels and apoptosis. Taken together, these observations suggest that statins cause apoptosis in myotube cultures in part by inhibiting the geranylgeranylation of proteins, but not by suppressing ubiquinone concentration. Furthermore, the data from primary hepatocytes suggests a cell-type differential

Mycobacterium avium MAV2052 protein induces apoptosis in murine macrophage cells through Toll-like receptor 4.

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Lee, Kang-In; Choi, Han-Gyu; Son, Yeo-Jin; Whang, Jake; Kim, Kwangwook; Jeon, Heat Sal; Park, Hye-Soo; Back, Yong Woo; Choi, Seunga; Kim, Seong-Woo; Choi, Chul Hee; Kim, Hwa-Jung

2016-04-01

Mycobacterium avium and its sonic extracts induce apoptosis in macrophages. However, little is known about the M. avium components regulating macrophage apoptosis. In this study, using multidimensional fractionation, we identified MAV2052 protein, which induced macrophage apoptosis in M. avium culture filtrates. The recombinant MAV2052 induced macrophage apoptosis in a caspase-dependent manner. The loss of mitochondrial transmembrane potential (ΔΨm), mitochondrial translocation of Bax, and release of cytochrome c from mitochondria were observed in macrophages treated with MAV2052. Further, reactive oxygen species (ROS) production was required for the apoptosis induced by MAV2052. In addition, ROS and mitogen-activated protein kinases were involved in MAV2052-mediated TNF-α and IL-6 production. ROS-mediated activation of apoptosis signal-regulating kinase 1 (ASK1)-JNK pathway was a major signaling pathway for MAV2052-induced apoptosis. Moreover, MAV2052 bound to Toll-like receptor (TLR) 4 molecule and MAV2052-induced ROS production, ΔΨm loss, and apoptosis were all significantly reduced in TLR4(-/-) macrophages. Altogether, our results suggest that MAV2052 induces apoptotic cell death through TLR4 dependent ROS production and JNK pathway in murine macrophages.

Role of Bax in resveratrol-induced apoptosis of colorectal carcinoma cells

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Mahyar-Roemer, Mojgan; Köhler, Hans; Roemer, Klaus

2002-01-01

The natural plant polyphenol resveratrol present in some foods including grapes, wine, and peanuts, has been implicated in the inhibition, delay, and reversion of cellular events associated with heart diseases and tumorigenesis. Recent work has suggested that the cancer chemoprotective effect of the compound is primarily linked to its ability to induce cell division cycle arrest and apoptosis, the latter possibly through the activation of pro-apoptotic proteins such as Bax. The expression, subcellular localization, and importance of Bax for resveratrol-provoked apoptosis were assessed in human HCT116 colon carcinoma cells and derivatives with both bax alleles inactivated. Low to moderate concentrations of resveratrol induced co-localization of cellular Bax protein with mitochondria, collapse of the mitochondrial membrane potential, activation of caspases 3 and 9, and finally, apoptosis. In the absence of Bax, membrane potential collapse was delayed, and apoptosis was reduced but not absent. Resveratrol inhibited the formation of colonies by both HCT116 and HCT116 bax -/- cells. Resveratrol at physiological doses can induce a Bax-mediated and a Bax-independent mitochondrial apoptosis. Both can limit the ability of the cells to form colonies

Susceptibility of different subsets of immature thymocytes to apoptosis induced by anti-TCRmAb

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Li Hongmei; Zhong Renqian; Yu Jiaping; Kong Xiantao; Chen Weifeng

2003-01-01

To analysis the susceptibility of different subsets of immature mice thymocytes to apoptosis induced by anti-TCRmAbs in vitro apoptosis was induced in unfractionated mice thymocytes by anti-TCRmAb. In Vivo apoptosis was induced in BALB/c mice by anti-TCR mAb, and thymocytes were examined by FACS. Results showed that CD4 + CD8 + DP thymocytes and CD4 - CD8 + CD3 - thymocytes were equally sensitive to apoptosis after treatment with the anti-TCR mAb. In sharp contrast, the early migrants or precursor containing thymocytes which are CD4 - CD8 - CD3 - TN have a lower spontaneous apoptosis rate and were relatively resistant to the anti-TCR mAb. The findings showed a breakpoint in thymocyte sensitivity to apoptosis which occurs after the onset of CD4 - CD8 + CD3 expression, suggesting that susceptibility of thymocytes to apoptosis is developmentally regulated

Gonadal steroids modulate Fas-induced apoptosis of lactotropes and somatotropes.

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Jaita, Gabriela; Zárate, Sandra; Ferrari, Luciana; Radl, Daniela; Ferraris, Jimena; Eijo, Guadalupe; Zaldivar, Verónica; Pisera, Daniel; Seilicovich, Adriana

2011-02-01

We have previously reported that Fas activation induces apoptosis of anterior pituitary cells from rats at proestrus but not at diestrus and in an estrogen-dependent manner. In this study, we evaluated the effect of Fas activation on apoptosis of lactotropes and somatotropes during the estrous cycle and explored the action of gonadal steroids on Fas-induced apoptosis. Also, we studied whether changes in Fas expression are involved in the apoptotic response of anterior pituitary cells. Fas activation increased the percentage of TUNEL-positive lactotropes and somatotropes at proestrus but not at diestrus. FasL triggered apoptosis of somatotropes only when cells from ovariectomized rats were cultured in the presence of 17 β-estradiol (E2). Progesterone (P4) blocked the apoptotic action of the Fas/FasL system in lactotropes and somatotropes incubated with E2. Both E2 and P4 increased the percentage of cells expressing Fas at the cell membrane. Our results show that Fas activation induces apoptosis of lactotropes and somatotropes at proestrus but not at diestrus. Gonadal steroids may be involved in the apoptotic response of lactotropes and somatotropes, suggesting that Fas activation is implicated in the renewal of these pituitary subpopulations during the estrous cycle. The effect of gonadal steroids on Fas expression may be only partially involved in regulation of the Fas/FasL apoptotic pathway in the anterior pituitary gland.

Norcantharidin (NCTD) induces mitochondria mediated apoptosis in ...

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Administrator

2011-06-15

Jun 15, 2011 ... cancer deaths for both sexes being attributable to hepatoma. However ..... Resveratrol induces apoptosis and cell cycle arrest of human T24 bladder cancer cells in ... involvement of the CD95 receptor/ligand. J. Cancer. Res.

Apoptosis of nasopharyngeal carcinoma cell line (CNE-2) induced by neutron irradiation

International Nuclear Information System (INIS)

Liang Ke; He Shaoqin; Feng Yan; Tang Jinhua; Feng Qinfu; Shen Yu; Yin Weibo; Xu Guozhen; Liu Xinfan; Wang Luhua; Gao Li

1999-01-01

Objective: To study the apoptotic response of the nasopharyngeal carcinoma cell line (CNE-2) induced by neutron irradiation. Methods: CNE-2 cells were cultured as usual. Using the techniques of DNA agarose gel electrophoresis and DNA special fluorescent staining, the status of apoptosis in CNE-2 cells after neutron irradiation was detected. Results: It was shown that the apoptosis can be induced in CNE-2 cell after neutron radiation. Six hrs, after different doses of neutron (0/0.667/1.333/2.000/2.667/3.333 Gy) and X-ray 0/2/4/6/8/10 Gy) irradiation the apoptotic rates were 2.4%, 6.3%, 7.1%, 9.5%, 13.5%, 14.6% and 2.4%, 3.8%, 5.7%, 7.8%, 10.4%, 11.7%, respectively; at 48 hrs they were 18.3%, 21.5%, 22.8%, 29.3%, 34.2% and 13.7%, 17.6%, 21.3%, 25.6%, 28.9%, respectively. At 10 hrs after neutron irradiation the DNA ladder of apoptosis could be detected between 0.667-3.333 Gy doses in CNE-2 cells by DNA agarose gel electrophoresis. Conclusion: Neutron radiation can induce apoptosis in tumor cells. Compared with the X-ray, neutron induces apoptosis in larger extent than X-ray in the same condition; meanwhile, apoptosis after irradiation is dose and time dependent

Kinetics of apoptotic markers in exogeneously induced apoptosis of EL4 cells.

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Jessel, Robert; Haertel, Steffen; Socaciu, Carmen; Tykhonova, Svetlana; Diehl, Horst A

2002-01-01

We investigated the time-dependence of apoptotic events in EL4 cells by monitoring plasma membrane changes in correlation to DNA fragmentation and cell shrinkage. We applied three apoptosis inducers (staurosporine, tubericidine and X-rays) and we looked at various markers to follow the early-to-late apoptotic events: phospholipid translocation (identified through annexin V-fluorescein assay and propidium iodide), lipid package (via merocyanine assay), membrane fluidity and anisotropy (via fluorescent measurements), DNA fragmentation by the fluorescence-labeling test and cell size measurements. The different apoptotic inducers caused different reactions of the cells: staurosporine induced apoptosis most rapidly in a high number of cells, tubercidine triggered apoptosis only in the S phase cells, while X-rays caused a G2/M arrest and subsequently apoptosis. Loss of lipid asymmetry is promptly detectable after one hour of incubation time. The phosphatidylserine translocation, decrease of lipid package and anisotropy, and the increase of membrane fluidity appeared to be based on the same process of lipid asymmetry loss. Therefore, the DNA fragmentation and the cell shrinkage appear to be parallel and independent processes running on different time scales but which are kinetically inter-related. The results indicate different signal steps to apoptosis dependent on inducer characteristics but the kinetics of "early-to-late" apoptosis appears to be a fixed program.

Canine distemper virus induces apoptosis in cervical tumor derived cell lines

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Rajão Daniela S

2011-06-01

Full Text Available Abstract Apoptosis can be induced or inhibited by viral proteins, it can form part of the host defense against virus infection, or it can be a mechanism for viral spread to neighboring cells. Canine distemper virus (CDV induces apoptotic cells in lymphoid tissues and in the cerebellum of dogs naturally infected. CDV also produces a cytopathologic effect, leading to apoptosis in Vero cells in tissue culture. We tested canine distemper virus, a member of the Paramyxoviridae family, for the ability to trigger apoptosis in HeLa cells, derived from cervical cancer cells resistant to apoptosis. To study the effect of CDV infection in HeLa cells, we examined apoptotic markers 24 h post infection (pi, by flow cytometry assay for DNA fragmentation, real-time PCR assay for caspase-3 and caspase-8 mRNA expression, and by caspase-3 and -8 immunocytochemistry. Flow cytometry showed that DNA fragmentation was induced in HeLa cells infected by CDV, and immunocytochemistry revealed a significant increase in the levels of the cleaved active form of caspase-3 protein, but did not show any difference in expression of caspase-8, indicating an intrinsic apoptotic pathway. Confirming this observation, expression of caspase-3 mRNA was higher in CDV infected HeLa cells than control cells; however, there was no statistically significant change in caspase-8 mRNA expression profile. Our data suggest that canine distemper virus induced apoptosis in HeLa cells, triggering apoptosis by the intrinsic pathway, with no participation of the initiator caspase -8 from the extrinsic pathway. In conclusion, the cellular stress caused by CDV infection of HeLa cells, leading to apoptosis, can be used as a tool in future research for cervical cancer treatment and control.

Enteral peptide formulas inhibit radiation induced enteritis and apoptosis in intestinal epithelial cells and suppress the expression and function of Alzheimer's and cell division control gene products

International Nuclear Information System (INIS)

Cope, F.O.; Issinger, O.G.; McArdle, A.H.; Shapiro, J.; Tomei, L.D.

1991-01-01

Studies have shown that patients receiving enteral peptide formulas prior to irradiation have a significantly reduced incidence of enteritis and express a profound increase in intestinal cellularity. Two conceptual approaches were taken to describe this response. First was the evaluation in changes in programmed intestinal cell death and secondly the evaluation of a gene product controlling cell division cycling. This study provided a relationship between the ratio of cell death to cell formulations. The results indicate that in the canine and murine models, irradiation induces expression of the Alzheimer's gene in intestinal crypt cells, while the incidence of apoptosis in apical cells is significantly increased. The use of peptide enteral formulations suppresses the expression of the Alzheimer's gene in crypt cells, while apoptosis is eliminated in the apical cells of the intestine. Concomitantly, enteral peptide formulations suppress the function of the CK-II gene product in the basal and baso-lateral cells of the intestine. These data indicate that although the mitotic index is significantly reduced in enterocytes, this phenomenon alone is not sufficient to account for the peptide-induced radio-resistance of the intestine. The data also indicate a significant reduction of normal apoptosis in the upper lateral and apical cells of the intestinal villi. Thus, the ratio of cell death to cell replacement is significantly decreased resulting in an increase in villus height and hypertrophy of the apical villus cells. Thus, peptide solutions should be considered as an adjunct treatment both in radio- and chemotherapy

Override of the radiation-induced mitotic block in human tumour cells by methylxanthines and its relationship to the potentiation of cytotoxicity

International Nuclear Information System (INIS)

Musk, S.R.R.; Steel, G.G.

1990-01-01

Caffeine, theophylline, theobromine and paraxanthine, were tested for ability to override mitotic block induced by ionizing radiation in the human bladder carcinoma cell line RT112. All were found to partially override the block, at a concentration of 1mM in the order caffeine > theophylline > theobromine = paraxanthine. At a concentration of 1 mM only caffeine was found to potentiate cell killing as well as causing block override; at higher concentrations all had a significant effect on survival but little or no further influence on the degree of block override. It is concluded that override of a mitotic block is not in itself sufficient to cause increased killing when irradiated cells are incubated in the presence of caffeine, and that caffeine exerts its potentiating effect by directly inhibiting repair of damage in DNA or by causing override of radiation-induced inhibition of DNA synthesis. (author)

Override of the radiation-induced mitotic block in human tumour cells by methylxanthines and its relationship to the potentiation of cytotoxicity

Energy Technology Data Exchange (ETDEWEB)

Musk, S.R.R.; Steel, G.G. (Institute of Cancer Research, Sutton (UK). Surrey Branch)

1990-06-01

Caffeine, theophylline, theobromine and paraxanthine, were tested for ability to override mitotic block induced by ionizing radiation in the human bladder carcinoma cell line RT112. All were found to partially override the block, at a concentration of 1mM in the order caffeine > theophylline > theobromine = paraxanthine. At a concentration of 1 mM only caffeine was found to potentiate cell killing as well as causing block override; at higher concentrations all had a significant effect on survival but little or no further influence on the degree of block override. It is concluded that override of a mitotic block is not in itself sufficient to cause increased killing when irradiated cells are incubated in the presence of caffeine, and that caffeine exerts its potentiating effect by directly inhibiting repair of damage in DNA or by causing override of radiation-induced inhibition of DNA synthesis. (author).

Butyrate down regulates BCL-XL and sensitizes human fibroblasts to radiation and chemotherapy induced apoptosis

International Nuclear Information System (INIS)

Chung, Diana H.; Ljungman, Mats; Zhang Fenfen; Chen Feng; McLaughlin, William P.

1997-01-01

Purpose/Objective: Butyrate is a short chain fatty acid that has been implicated in the induction of cell cycle arrest, cell differentiation and apoptosis. The purpose of this study was to determine if butyrate treatment sensitizes cells to radiation or chemotherapy induced apoptosis. Materials and Methods: Normal neonatal human diploid fibroblasts were used throughout this study. Apoptosis was scored and quantified using three different methods. First, cell morphology using propidium iodide and fluorescence microscopy was used to qualitatively determine apoptosis and to quantify the percentage of cells undergoing apoptosis. Second, apoptosis induced DNA degradation was scored by quantifying the amount of cells appearing in a sub-G1 peak using fixed and PI-stained cells and flow cytometry. Third, apoptosis-induced DNA degradation was examined by using an assay involving direct lysis of cells in the wells of agarose gels followed by conventional gel electrophoresis. Western blotting was used to quantify the cellular levels of the apoptosis regulators, Bcl-2, Bcl-XL and Bax. Results: Human diploid fibroblasts, which were resistant to radiation induced apoptosis, were found to undergo massive apoptosis when radiation was combined with butyrate treatment. Sensitization was obtained when butyrate was added before or after radiation although the combination of both pre and post-treatment was the most effective. Butyrate was also found to enhance UV light and cisplatin-induced apoptosis. These findings correlated with a reduction of the apoptosis antagonist Bcl-XL. Bcl-XL levels significantly dropped in a time and dose dependent manner. In addition, butyrate effectively blocked UV-induced accumulation of p53. Conclusion: Our results suggest that butyrate may be an attractive agent to use in combination with radiation or chemotherapy to lower the apoptotic threshold of tumor cells, regardless of the p53 status of the tumor cells

A microtubule inhibitor, ABT-751, induces autophagy and delays apoptosis in Huh-7 cells

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Wei, Ren-Jie [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Department of Pathology, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan (China); Lin, Su-Shuan [Department of Pathology, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan (China); Wu, Wen-Ren [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Chen, Lih-Ren [Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan (China); Division of Physiology, Livestock Research Institute, Council of Agriculture, Taiwan (China); Li, Chien-Feng [Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan, Taiwan (China); Department of Pathology, Chi-Mei Medical Center, Tainan, Taiwan (China); National Institute of Cancer Research, National Health Research Institute, Tainan, Taiwan (China); Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Chen, Han-De; Chou, Chien-Ting; Chen, Ya-Chun [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Liang, Shih-Shin [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Chien, Shang-Tao [Department of Pathology, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan (China); Shiue, Yow-Ling, E-mail: ylshiue@mail.nsysu.edu.tw [Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan (China); Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung, Taiwan (China)

2016-11-15

The objective was to investigate the upstream mechanisms of apoptosis which were triggered by a novel anti-microtubule drug, ABT-751, in hepatocellular carcinoma-derived Huh-7 cells. Effects of ABT-751 were evaluated by immunocytochemistry, flow cytometric, alkaline comet, soft agar, immunoblotting, CytoID, green fluorescent protein-microtubule associated protein 1 light chain 3 beta detection, plasmid transfection, nuclear/cytosol fractionation, coimmunoprecipitation, quantitative reverse transcription-polymerase chain reaction, small-hairpin RNA interference and mitochondria/cytosol fractionation assays. Results showed that ABT-751 caused dysregulation of microtubule, collapse of mitochondrial membrane potential, generation of reactive oxygen species (ROS), DNA damage, G{sub 2}/M cell cycle arrest, inhibition of anchorage-independent cell growth and apoptosis in Huh-7 cells. ABT-751 also induced early autophagy via upregulation of nuclear TP53 and downregulation of the AKT serine/threonine kinase (AKT)/mechanistic target of rapamycin (MTOR) pathway. Through modulation of the expression levels of DNA damage checkpoint proteins and G{sub 2}/M cell cycle regulators, ABT-751 induced G{sub 2}/M cell cycle arrest. Subsequently, ABT-751 triggered apoptosis with marked downregulation of B-cell CLL/lymphoma 2, upregulation of mitochondrial BCL2 antagonist/killer 1 and BCL2 like 11 protein levels, and cleavages of caspase 8 (CASP8), CASP9, CASP3 and DNA fragmentation factor subunit alpha proteins. Suppression of ROS significantly decreased ABT-751-induced autophagic and apoptotic cells. Pharmacological inhibition of autophagy significantly increased the percentages of ABT-751-induced apoptotic cells. The autophagy induced by ABT-751 plays a protective role to postpone apoptosis by exerting adaptive responses following microtubule damage, ROS and/or impaired mitochondria. - Highlights: • An anti-microtubule agent, ABT-751, induces autophagy and apoptosis in Huh-7 cells. �

Ultraviolet B irradiation of human leukaemia HL-60 cells in vitro induces apoptosis

International Nuclear Information System (INIS)

Martin, S.J.; Cotter, T.G.

1991-01-01

UV radiation is known to be a potent agent for the induction of programmed cell death (apoptosis) in human skin. However, the mechanistic aspects of UV-induced apoptosis remain ill-defined. In this study the effects of varying periods of UV-irradiation on the human leukaemia HL-60 cell line and on five other human cell lines were investigated.HL-60 cells were found to rapidly undergo apoptosis en masse after short periods of UV-irradiation whereas prolonged exposure of these cells to this form of radiation induced a more rapid form of cell death which was suggestive of necrosis, the pathological mode of cell death. UV-induced apoptosis in cell lines was characterized by morphological changes as well as DNA fragmentation into unit multiples of ∼ 200 bp, which was indicative of endogenous endonuclease activation. This DNA fragmentation pattern was not detected in cells immediately after UV-irradiation, and was therefore not the result of direct UV-induced DNA damage. UV-induced apoptosis of the HL-60 cell line was found to require extracellular calcium and to be inhibited in a dose-dependent way by zinc added to the culture medium. (author)

Combined application of arsenic trioxide and lithium chloride augments viability reduction and apoptosis induction in human rhabdomyosarcoma cell lines.

Directory of Open Access Journals (Sweden)

Sabine B Schleicher

Full Text Available Rhabdomyosarcomas (RMS are the most prevalent soft tissue sarcomas affecting children and adolescents. Despite intensive treatment consisting of multimodal chemotherapy and surgery RMS patients diagnosed with metastatic disease expect long term survival rates of only 20%. Often multidrug resistance arises upon initial response emphasizing the need for new therapeutic drugs to improve treatment efficiency. Previously, we demonstrated the efficacy of the FDA approved drug arsenic trioxide (ATO specifically inhibiting viability and clonal growth as well as inducing cell death in human RMS cell lines of different subtypes. In this study, we combined low dose ATO with lithium chloride (LiCl, which is approved as mood stabilizer for the treatment of bipolar disorder, but also inhibits growth and survival of different cancer cell types in pre-clinical research. Indeed, we could show additive effects of LiCl and ATO on viability reduction, decrease of colony formation as well as cell death induction. In the course of this, LiCl induced inhibitory glycogen synthase kinase-3β (GSK-3β serine 9 phosphorylation, whereas glioma associated oncogene family 1 (GLI1 protein expression was particularly reduced by combined ATO and LiCl treatment in RD and RH-30 cell lines, showing high rates of apoptotic cell death. These results imply that combination of ATO with LiCl or another drug targeting GSK-3 is a promising strategy to enforce the treatment efficiency in resistant and recurrent RMS.

UV-induced mitotic co-segregation of genetic markers in Candida albicans: Evidence for linkage

International Nuclear Information System (INIS)

Crandall, M.

1983-01-01

Parasexual genetic studies of the medically important yeast Candida albicans were performed using the method of UV-induced mitotic segregation. UV-irradiation of the Hoffmann-La Roche type culture of C. albicans yielded a limited spectrum of mutants at a relatively high fequency. This observation suggested natural heterozygosity. Canavanine-sensitive (CanS) segregants were induced at a frequency of 7.6 . 10 -3 . Double mutants that were both CanS and methionine (Met - ) auxotrophs were induced at a frequency of 7.4 . 10 -3 . The single Met - segregant class was missing indicating linkage. UV-induced CanS or Met - CanS segregants occurred occasionally in twin-sectored colonies. Analyses of the sectors as well as the observed and missing classes of segregants indicated that genes met and can are linked in the cis configuration. The proposed gene order is: centromere - met - can. Thus, it is concluded that the Hoffmann-La Roche strain of C. albicans is naturally heterozygous at two linked loci. These findings are consistent with diploidy. (orig.)

Dissection of pathways leading to antigen receptor-induced and Fas/CD95-induced apoptosis in human B cells

NARCIS (Netherlands)

Lens, S. M.; den Drijver, B. F.; Pötgens, A. J.; Tesselaar, K.; van Oers, M. H.; van Lier, R. A.

1998-01-01

To dissect intracellular pathways involved in B cell Ag receptor (BCR)-mediated and Fas-induced human B cell death, we isolated clones of the Burkitt lymphoma cell line Ramos with different apoptosis sensitivities. Selection for sensitivity to Fas-induced apoptosis also selected for clones with

Regulation of radiation-induced protein kinase Cδ activation in radiation-induced apoptosis differs between radiosensitive and radioresistant mouse thymic lymphoma cell lines

International Nuclear Information System (INIS)

Nakajima, Tetsuo; Yukawa, Osami; Tsuji, Hideo; Ohyama, Harumi; Wang, Bing; Tatsumi, Kouichi; Hayata, Isamu; Hama-Inaba, Hiroko

2006-01-01

Protein kinase Cδ (PKCδ) has an important role in radiation-induced apoptosis. The expression and function of PKCδ in radiation-induced apoptosis were assessed in a radiation-sensitive mouse thymic lymphoma cell line, 3SBH5, and its radioresistant variant, XR223. Rottlerin, a PKCδ-specific inhibitor, completely abolished radiation-induced apoptosis in 3SBH5. Radiation-induced PKCδ activation correlated with the degradation of PKCδ, indicating that PKCδ activation through degradation is involved in radiation-induced apoptosis in radiosensitive 3SBH5. In radioresistant XR223, radiation-induced PKCδ activation was lower than that in radiosensitive 3SBH5. Cytosol PKCδ levels in 3SBH5 decreased markedly after irradiation, while those in XR223 did not. There was no apparent change after irradiation in the membrane fractions of either cell type. In addition, basal cytosol PKCδ levels in XR223 were higher than those in 3SBH5. These results suggest that the radioresistance in XR223 to radiation-induced apoptosis is due to a difference in the regulation of radiation-induced PKCδ activation compared to that of 3SBH5. On the other hand, Atm -/- mouse thymic lymphoma cells were more radioresistant to radiation-induced apoptosis than wild-type mouse thymic lymphoma cells. Irradiated wild-type cells, but not Atm -/- cells, had decreased PKCδ levels, indicating that the Atm protein is involved in radiation-induced apoptosis through the induction of PKCδ degradation. The decreased Atm protein levels induced by treatment with Atm small interfering RNA had no effect on radiation-induced apoptosis in 3SBH5 cells. These results suggest that the regulation of radiation-induced PKCδ activation, which is distinct from the Atm-mediated cascade, determines radiation sensitivity in radiosensitive 3SBH5 cells

BIM is the primary mediator of MYC-induced apoptosis in multiple solid tissues.

Science.gov (United States)

Muthalagu, Nathiya; Junttila, Melissa R; Wiese, Katrin E; Wolf, Elmar; Morton, Jennifer; Bauer, Barbara; Evan, Gerard I; Eilers, Martin; Murphy, Daniel J

2014-09-11

MYC is one of the most frequently overexpressed oncogenes in human cancer, and even modestly deregulated MYC can initiate ectopic proliferation in many postmitotic cell types in vivo. Sensitization of cells to apoptosis limits MYC's oncogenic potential. However, the mechanism through which MYC induces apoptosis is controversial. Some studies implicate p19ARF-mediated stabilization of p53, followed by induction of proapoptotic BH3 proteins NOXA and PUMA, whereas others argue for direct regulation of BH3 proteins, especially BIM. Here, we use a single experimental system to systematically evaluate the roles of p19ARF and BIM during MYC-induced apoptosis, in vitro, in vivo, and in combination with a widely used chemotherapeutic, doxorubicin. We find a common specific requirement for BIM during MYC-induced apoptosis in multiple settings, which does not extend to the p53-responsive BH3 family member PUMA, and find no evidence of a role for p19ARF during MYC-induced apoptosis in the tissues examined. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Apoptosis-promoted tumorigenesis: γ-irradiation-induced thymic lymphomagenesis requires Puma-driven leukocyte death

OpenAIRE

Michalak, Ewa M.; Vandenberg, Cassandra J.; Delbridge, Alex R.D.; Wu, Li; Scott, Clare L.; Adams, Jerry M.; Strasser, Andreas

2010-01-01

Although tumor development requires impaired apoptosis, we describe a novel paradigm of apoptosis-dependent tumorigenesis. Because DNA damage triggers apoptosis through p53-mediated induction of BH3-only proteins Puma and Noxa, we explored their roles in γ-radiation-induced thymic lymphomagenesis. Surprisingly, whereas Noxa loss accelerated it, Puma loss ablated tumorigenesis. Tumor suppression by Puma deficiency reflected its protection of leukocytes from γ-irradiation-induced death, because...

Bupivacaine-induced apoptosis independently of WDR35 expression in mouse neuroblastoma Neuro2a cells

Science.gov (United States)

2012-01-01

Background Bupivacaine-induced neurotoxicity has been shown to occur through apoptosis. Recently, bupivacaine was shown to elicit reactive oxygen species (ROS) production and induce apoptosis accompanied by activation of p38 mitogen-activated protein kinase (MAPK) in a human neuroblastoma cell line. We have reported that WDR35, a WD40-repeat protein, may mediate apoptosis through caspase-3 activation. The present study was undertaken to test whether bupivacaine induces apoptosis in mouse neuroblastoma Neuro2a cells and to determine whether ROS, p38 MAPK, and WDR35 are involved. Results Our results showed that bupivacaine induced ROS generation and p38 MAPK activation in Neuro2a cells, resulting in apoptosis. Bupivacaine also increased WDR35 expression in a dose- and time-dependent manner. Hydrogen peroxide (H2O2) also increased WDR35 expression in Neuro2a cells. Antioxidant (EUK-8) and p38 MAPK inhibitor (SB202190) treatment attenuated the increase in caspase-3 activity, cell death and WDR35 expression induced by bupivacaine or H2O2. Although transfection of Neuro2a cells with WDR35 siRNA attenuated the bupivacaine- or H2O2-induced increase in expression of WDR35 mRNA and protein, in contrast to our previous studies, it did not inhibit the increase in caspase-3 activity in bupivacaine- or H2O2-treated cells. Conclusions In summary, our results indicated that bupivacaine induced apoptosis in Neuro2a cells. Bupivacaine induced ROS generation and p38 MAPK activation, resulting in an increase in WDR35 expression, in these cells. However, the increase in WDR35 expression may not be essential for the bupivacaine-induced apoptosis in Neuro2a cells. These results may suggest the existence of another mechanism of bupivacaine-induced apoptosis independent from WDR35 expression in Neuro2a cells. PMID:23227925

Proteasomal Dysfunction Induced By Diclofenac Engenders Apoptosis Through Mitochondrial Pathway.

Science.gov (United States)

Amanullah, Ayeman; Upadhyay, Arun; Chhangani, Deepak; Joshi, Vibhuti; Mishra, Ribhav; Yamanaka, Koji; Mishra, Amit

2017-05-01

Diclofenac is the most commonly used phenylacetic acid derivative non-steroidal anti-inflammatory drug (NSAID) that demonstrates significant analgesic, antipyretic, and anti-inflammatory effects. Several epidemiological studies have demonstrated anti-proliferative activity of NSAIDs and examined their apoptotic induction effects in different cancer cell lines. However, the precise molecular mechanisms by which these pharmacological agents induce apoptosis and exert anti-carcinogenic properties are not well known. Here, we have observed that diclofenac treatment induces proteasome malfunction and promotes accumulation of different critical proteasome substrates, including few pro-apoptotic proteins in cells. Exposure of diclofenac consequently elevates aggregation of various ubiquitylated misfolded proteins. Finally, we have shown that diclofenac treatment promotes apoptosis in cells, which could be because of mitochondrial membrane depolarization and cytochrome c release into cytosol. This study suggests possible beneficial insights of NSAIDs-induced apoptosis that may improve our existing knowledge in anti-proliferative interspecific strategies development. J. Cell. Biochem. 118: 1014-1027, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

NFAT2 mediates high glucose-induced glomerular podocyte apoptosis through increased Bax expression

International Nuclear Information System (INIS)

Li, Ruizhao; Zhang, Li; Shi, Wei; Zhang, Bin; Liang, Xinling; Liu, Shuangxin; Wang, Wenjian

2013-01-01

Background: Hyperglycemia promotes podocyte apoptosis and plays a key role in the pathogenesis of diabetic nephropathy. However, the mechanisms that mediate hyperglycemia-induced podocyte apoptosis is still far from being fully understood. Recent studies reported that high glucose activate nuclear factor of activated T cells (NFAT) in vascular smooth muscle or pancreatic β-cells. Here, we sought to determine if hyperglycemia activates NFAT2 in cultured podocyte and whether this leads to podocyte apoptosis. Meanwhile, we also further explore the mechanisms of NFAT2 activation and NFAT2 mediates high glucose-induced podocyte apoptosis. Methods: Immortalized mouse podocytes were cultured in media containing normal glucose (NG), or high glucose (HG) or HG plus cyclosporine A (a pharmacological inhibitor of calcinerin) or 11R-VIVIT (a special inhibitor of NFAT2). The activation of NFAT2 in podocytes was detected by western blotting and immunofluorescence assay. The role of NFAT2 in hyperglycemia-induced podocyte apoptosis was further evaluated by observing the inhibition of NFAT2 activation by 11R-VIVIT using flow cytometer. Intracellular Ca 2+ was monitored in HG-treated podcocytes using Fluo-3/AM. The mRNA and protein expression of apoptosis gene Bax were measured by real time-qPCR and western blotting. Results: HG stimulation activated NFAT2 in a time- and dose-dependent manner in cultured podocytes. Pretreatment with cyclosporine A (500 nM) or 11R-VIVIT (100 nM) completely blocked NFAT2 nuclear accumulation. Meanwhile, the apoptosis effects induced by HG were also abrogated by concomitant treatment with 11R-VIVIT in cultured podocytes. We further found that HG also increased [Ca 2+ ]i, leading to activation of calcineurin, and subsequent increased nuclear accumulation of NFAT2 and Bax expression in cultured podocytes. Conclusion: Our results identify a new finding that HG-induced podocyte apoptosis is mediated by calcineurin/NFAT2/Bax signaling pathway, which may

NFAT2 mediates high glucose-induced glomerular podocyte apoptosis through increased Bax expression

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Li, Ruizhao, E-mail: liruizhao1979@126.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Zhang, Li, E-mail: Zhanglichangde@163.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Southern Medical University, Guangzhou, Guangdong (China); Shi, Wei, E-mail: shiwei.gd@139.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Zhang, Bin, E-mail: zhangbinyes@yahoo.com.cn [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Liang, Xinling, E-mail: xinlingliang@yahoo.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Liu, Shuangxin, E-mail: mplsxi@yahoo.com.cn [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Wang, Wenjian, E-mail: wwjph@yahoo.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China)

2013-04-15

Background: Hyperglycemia promotes podocyte apoptosis and plays a key role in the pathogenesis of diabetic nephropathy. However, the mechanisms that mediate hyperglycemia-induced podocyte apoptosis is still far from being fully understood. Recent studies reported that high glucose activate nuclear factor of activated T cells (NFAT) in vascular smooth muscle or pancreatic β-cells. Here, we sought to determine if hyperglycemia activates NFAT2 in cultured podocyte and whether this leads to podocyte apoptosis. Meanwhile, we also further explore the mechanisms of NFAT2 activation and NFAT2 mediates high glucose-induced podocyte apoptosis. Methods: Immortalized mouse podocytes were cultured in media containing normal glucose (NG), or high glucose (HG) or HG plus cyclosporine A (a pharmacological inhibitor of calcinerin) or 11R-VIVIT (a special inhibitor of NFAT2). The activation of NFAT2 in podocytes was detected by western blotting and immunofluorescence assay. The role of NFAT2 in hyperglycemia-induced podocyte apoptosis was further evaluated by observing the inhibition of NFAT2 activation by 11R-VIVIT using flow cytometer. Intracellular Ca{sup 2+} was monitored in HG-treated podcocytes using Fluo-3/AM. The mRNA and protein expression of apoptosis gene Bax were measured by real time-qPCR and western blotting. Results: HG stimulation activated NFAT2 in a time- and dose-dependent manner in cultured podocytes. Pretreatment with cyclosporine A (500 nM) or 11R-VIVIT (100 nM) completely blocked NFAT2 nuclear accumulation. Meanwhile, the apoptosis effects induced by HG were also abrogated by concomitant treatment with 11R-VIVIT in cultured podocytes. We further found that HG also increased [Ca{sup 2+}]i, leading to activation of calcineurin, and subsequent increased nuclear accumulation of NFAT2 and Bax expression in cultured podocytes. Conclusion: Our results identify a new finding that HG-induced podocyte apoptosis is mediated by calcineurin/NFAT2/Bax signaling pathway

Intraarterial beta irradiation induces smooth muscle cell apoptosis and reduces medial cellularity in a hypercholesterolemic rabbit restenosis model

International Nuclear Information System (INIS)

Verin, Vitali; Popowski, Youri; Bochaton-Piallat, Marie-Luce; Belenger, Jacques; Urban, Philip; Neuville, Pascal; Redard, Mireille; Costa, Manuel; Celetta, Giuseppe; Gabbiani, Giulio

2000-01-01

Purpose: Ionizing radiation has been shown to be a powerful inhibitor of neointimal hyperplasia following arterial injury in several animal models of post-percutaneous transluminal coronary angioplasty (post-PTCA) restenosis. This was previously shown to be associated with a reduction in smooth muscle cell (SMC) mitotic activity. This study evaluated the effect of intraarterial beta irradiation on the arterial wall SMC density and apoptosis. Methods and Materials: Twenty-five carotid and 7 iliac arteries of hypercholesterolemic New Zealand white rabbits were injured using the Baumgartner technique. The impact of an 18 Gy beta radiation dose administered after balloon injury was studied and compared to a nonirradiated injured control group. The medial SMC density as well as the percentage of apoptotic cells were determined at 8 days, 21 days, and 6 weeks after injury using an automated computer-based software. Apoptotic cells were identified using in situ end-labeling of fragmented DNA. Results: The values for medial apoptosis in control vs. irradiated arteries were: 0.014 ± 0.023 vs. 0.23 ± 0.28%, p = NS, at 8 days; 0.012 ± 0.018 vs. 0.07 ± 0.07%, p = 0.05, at 21 days; and 0 ± 0 vs. 0.16 ± 0.11%, p = 0.03, at 6 weeks. The overall incidence of medial apoptotic cells at all time points was 0.01 ± 0.017 vs. 0.13 ± 0.14% in controls and irradiated arteries respectively, p = 0.004. Medial SMC density was significantly decreased in irradiated arteries in comparison with controls (p < 0.01 at all time-points). Conclusions: Intraarterial beta irradiation stimulates medial SMC apoptosis in balloon-injured arteries. This, together with a decrease in SMC mitotic activity, contributes to a decrease in the arterial wall cellularity

Palmitate induces VSMC apoptosis via toll like receptor (TLR)4/ROS/p53 pathway.

Science.gov (United States)

Zhang, Yuanjun; Xia, Guanghao; Zhang, Yaqiong; Liu, Juxiang; Liu, Xiaowei; Li, Weihua; Lv, Yaya; Wei, Suhong; Liu, Jing; Quan, Jinxing

2017-08-01

Toll-like receptor 4 (TLR4) has been implicated in vascular inflammation, as well as in the pathogenesis of atherosclerosis and diabetes. Vascular smooth muscle cell (VSMC) apoptosis has been shown to induce plaque vulnerability in atherosclerosis. Previous studies reported that palmitate induced apoptosis in VSMCs; however, the role of TLR4 in palmitate-induced apoptosis in VSMCs has not yet been defined. In this study, we investigated whether or not palmitate-induced apoptosis depended on the activation of the TLR4 pathway. VSMCs were treated with or without palmitate, CRISPR/Cas9z-mediated genome editing methods were used to deplete TLR4 expression, while NADPH oxidase inhibitors were used to inhibit reactive oxygen species (ROS) generation. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, ROS was measured using the 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) method, the mRNA and protein expression levels of caspase 3, caspase 9, BCL-2 and p53 were studied by real-time polymerase chain reaction (RT-PCR) and ELISA. Palmitate significantly promotes VSMC apoptosis, ROS generation, and expression of caspase 3, caspase 9 and p53; while NADPH oxidase inhibitor pretreatment markedly attenuated these effects. Moreover, knockdown of TLR4 significantly blocked palmitate-induced ROS generation and VSMC apoptosis accompanied by inhibition of caspase 3, caspase 9, p53 expression and restoration of BCL-2 expression. Our results suggest that palmitate-induced apoptosis depends on the activation of the TLR4/ROS/p53 signaling pathway, and that TLR4 may be a potential therapeutic target for the prevention and treatment of atherosclerosis. Copyright © 2017 Elsevier B.V. All rights reserved.

In Vivo Imaging of Apoptosis in Oncology: An Update

Directory of Open Access Journals (Sweden)

Christel Vangestel

2011-09-01

Full Text Available In this review, data on noninvasive imaging of apoptosis in oncology are reviewed. Imaging data available are presented in order of occurrence in time of enzymatic and morphologic events occurring during apoptosis. Available studies suggest that various radiopharmaceutical probes bear great potential for apoptosis imaging by means of positron emission tomography and single-photon emission computed tomography (SPECT. However, for several of these probes, thorough toxicologic studies are required before they can be applied in clinical studies. Both preclinical and clinical studies support the notion that 99mTc-hydrazinonicoti-namide-annexin A5 and SPECT allow for noninvasive, repetitive, quantitative apoptosis imaging and for assessing tumor response as early as 24 hours following treatment instigation. Bioluminescence imaging and near-infrared fluorescence imaging have shown great potential in small-animal imaging, but their usefulness for in vivo imaging in humans is limited to structures superficially located in the human body. Although preclinical tumor-based data using high-frequency-ultrasonography (US are promising, whether or not US will become a routinely clinically useful tool in the assessment of therapy response in oncology remains to be proven. The potential of magnetic resonance imaging (MRI and magnetic resonance spectroscopy (MRS for imaging late apoptotic processes is currently unclear. Neither 31P MRS nor 1H MRS signals seems to be a unique identifier for apoptosis. Although MRI-measured apparent diffusion coefficients are altered in response to therapies that induce apoptosis, they are also altered by nonapoptotic cell death, including necrosis and mitotic catastrophe. In the future, rapid progress in the field of apoptosis imaging in oncology is expected.

Cyclic GMP protects human macrophages against peroxynitrite-induced apoptosis.

Science.gov (United States)

Shaw, Catherine A; Webb, David J; Rossi, Adriano G; Megson, Ian L

2009-05-07

Nitric oxide (NO) can be both pro- and anti-apoptotic in various cell types, including macrophages. This apparent paradox may result from the actions of NO-related species generated in the microenvironment of the cell, for example the formation of peroxynitrite (ONOO-). In this study we have examined the ability of NO and ONOO- to evoke apoptosis in human monocyte-derived macrophages (MDMvarphi), and investigated whether preconditioning by cyclic guanosine monophosphate (cGMP) is able to limit apoptosis in this cell type. Characterisation of the NO-related species generated by (Z)-1- [2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate (DETA/NO) and 1,2,3,4-oxatriazolium, 5-amino-3-(3,4-dichlorophenyl)-, chloride (GEA-3162) was performed by electrochemistry using an isolated NO electrode and electron paramagnetic resonance (EPR) spectrometry. Mononuclear cells were isolated from peripheral blood of healthy volunteers and cultured to allow differentiation into MDMvarphi. Resultant MDMvarphi were treated for 24 h with DETA/NO (100 - 1000 muM) or GEA-3162 (10 - 300 muM) in the presence or absence of BAY 41-2272 (1 muM), isobutylmethylxanthine (IBMX; 1 muM), 1H- [1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one (ODQ; 20 muM) or 8-bromo-cGMP (1 mM). Apoptosis in MDMvarphi was assessed by flow cytometric analysis of annexin V binding in combination with propidium iodide staining. Electrochemistry and EPR revealed that DETA/NO liberated free NO radical, whilst GEA-3162 concomitantly released NO and O2-, and is therefore a ONOO- generator. NO (DETA/NO) had no effect on cell viability, but ONOO- (GEA-3162) caused a concentration-dependent induction of apoptosis in MDMvarphi. Preconditioning of MDMvarphi with NO in combination with the phosphodiesterase inhibitor, 3-Isobutyl-1-methylxanthine (IBMX), or the NO-independent stimulator of soluble guanylate cyclase, BAY 41-2272, significantly attenuated ONOO--induced apoptosis in a cGMP-dependent manner. These results

Cyclic GMP protects human macrophages against peroxynitrite-induced apoptosis

Directory of Open Access Journals (Sweden)

Rossi Adriano G

2009-05-01

Full Text Available Abstract Background Nitric oxide (NO can be both pro- and anti-apoptotic in various cell types, including macrophages. This apparent paradox may result from the actions of NO-related species generated in the microenvironment of the cell, for example the formation of peroxynitrite (ONOO-. In this study we have examined the ability of NO and ONOO- to evoke apoptosis in human monocyte-derived macrophages (MDMϕ, and investigated whether preconditioning by cyclic guanosine monophosphate (cGMP is able to limit apoptosis in this cell type. Methods Characterisation of the NO-related species generated by (Z-1- [2-(2-aminoethyl-N-(2-ammonioethylamino]diazen-1-ium-1,2-diolate (DETA/NO and 1,2,3,4-oxatriazolium, 5-amino-3-(3,4-dichlorophenyl-, chloride (GEA-3162 was performed by electrochemistry using an isolated NO electrode and electron paramagnetic resonance (EPR spectrometry. Mononuclear cells were isolated from peripheral blood of healthy volunteers and cultured to allow differentiation into MDMϕ. Resultant MDMϕ were treated for 24 h with DETA/NO (100 – 1000 μM or GEA-3162 (10 – 300 μM in the presence or absence of BAY 41–2272 (1 μM, isobutylmethylxanthine (IBMX; 1 μM, 1H- [1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one (ODQ; 20 μM or 8-bromo-cGMP (1 mM. Apoptosis in MDMϕ was assessed by flow cytometric analysis of annexin V binding in combination with propidium iodide staining. Results Electrochemistry and EPR revealed that DETA/NO liberated free NO radical, whilst GEA-3162 concomitantly released NO and O2-, and is therefore a ONOO- generator. NO (DETA/NO had no effect on cell viability, but ONOO- (GEA-3162 caused a concentration-dependent induction of apoptosis in MDMϕ. Preconditioning of MDMϕ with NO in combination with the phosphodiesterase inhibitor, 3-Isobutyl-1-methylxanthine (IBMX, or the NO-independent stimulator of soluble guanylate cyclase, BAY 41–2272, significantly attenuated ONOO--induced apoptosis in a cGMP-dependent manner

Apoptosis and radiosensitivity induced by N-acety1 phytosphingosine, in human cancer cell line

International Nuclear Information System (INIS)

Kim, Y. H.; Kim, K. S.; Han, Y. S.; Jeon, S. J.; Song, J. Y.; Jung, I. S.; Hong, S. H.; Yun, Y. S.; Park, J. S.

2004-01-01

Ceramide is a key lipid molecule in signal transduction with a role in various regulatory pathways including differentiation, proliferation and especially apoptosis. Ionizing radiation-induced apoptosis is associated with accumulation of ceramide, and the sphingomyelinase deficiency results in radioresistance. We investigated the exogenous treatment of N-acetyl-phytosphingosine (NAPS), an analogue of N-acetyl-sphingosine (C 2 -Ceramide), and C 2 -ceramide exert apoptotic effect on human T cell lymphoma Jurkat cells and breast cancer cell line MDA-MB-231. NAPS and C 2 -Ceramide has cytotoxic effect in time- and dose-dependent manner, and increased caspase-3, 8 activity. However, NAPS induced apoptosis more effectively, and increased caspase activity induced by NAPS is more higher than C 2 -ceramide. Moreover, NAPS decreased clonogenicity of irradiated cells and increased radiation-induced apoptosis significantly. Increased cell death by irradiation in the presence of NAPS is owing to the increase of caspase activity. These data suggest that NAPS might be used for lead as a new type of radiosensitizing agent increasing radiation-induced apoptosis

Cloning and Characterization of Genes that Inhibit TRAIL-Induced Apoptosis of Breast Cancer Cells

National Research Council Canada - National Science Library

Shu, Hong-Bing

2003-01-01

...). However, some cancer cells are resistant to TRAIL-induced apoptosis (3, 4, 6-13). The purpose of this proposed study is to clone and characterize such inhibitory genes of TRAIL-induced apoptosis...

Ellipticine induces apoptosis in T-cell lymphoma via oxidative DNA damage

DEFF Research Database (Denmark)

Savorani, Cecilia; Manfé, Valentina; Biskup, Edyta

2015-01-01

(CTCL), a disease that is progressive, chemoresistant and refractory to treatment. We tested the effect of ellipticine in three cell lines with different p53 status: MyLa2000 (p53(wt/wt)), SeAx ((G245S)p53) and Hut-78 ((R196Stop)p53). Ellipticine caused apoptosis in MyLa2000 and SeAx and restored...... the transcriptional activity of (G245S)p53 in SeAx. However, p53 siRNA knockdown experiments revealed that p53 was not required for ellipticine-induced apoptosis in CTCL. The lipophilic antioxidant α-tocopherol inhibited ellipticine-dependent apoptosis and we linked the apoptotic response to the oxidative DNA damage....... Our results provide evidence that ellipticine-induced apoptosis is exerted through DNA damage and does not require p53 activation in T-cell lymphoma....

Human retinal pigment epithelial cell-induced apoptosis in activated T cells

DEFF Research Database (Denmark)

Jørgensen, A; Wiencke, A K; la Cour, M

1998-01-01

PURPOSE: The immune privilege of the eye has been thought to be dependent on physical barriers and absence of lymphatic vessels. However, the immune privilege may also involve active immunologic processes, as recent studies have indicated. The purpose of the present study was to investigate whether...... human retinal pigment epithelial (RPE) cells can induce apoptosis in activated T cells. METHODS: Fas ligand (FasL) expression was detected by flow cytometry and immunohistochemistry. Cultured RPE cells were cocultured with T-cell lines and peripheral blood lymphocytes for 6 hours to 2 days. Induction...... of apoptosis was detected by 7-amino-actinomycin D and annexin V staining. RESULTS: Retinal pigment epithelial cells expressed FasL and induced apoptosis in activated Fas+ T cells. Blocking of Fas-FasL interaction with antibody strongly inhibited RPE-mediated T-cell apoptosis. Retinal pigment epithelial cells...

Roles of acid sphingomyelinase activation in neuronal cells apoptosis induced by microwave irradiation

International Nuclear Information System (INIS)

Zhang Lei; Xu Shangcheng; Zhang Guangbin; Yu Zhengping

2009-01-01

The present study is to examine the effect of microwave on acid sphingomyelinase (ASM) activity and expression, and to explore the role of ASM activation in neuronal cells apoptosis induced by microwave irradiation. Primary cultured hippocampal neurons were irradiated by 30 W/cm 2 microwave for 10 min, and ASM activity assay was used to investigate ASM activity alteration. RT-PCR and western blot were used to detect ASM mRNA and protein expression respectively. Apoptosis was observed by Hoechst 33342 fluorescence staining. ASM specific inhibitor imipramine was applied to inhibit ASM activation. It has been found that apoptosis rate of primary cultured hippocampal neurons increased significantly after microwave irradiation. ASM was activated while ASM mRNA and protein expression were upregulated in neurons after microwave irradiation. Pretreatment with imipramine could reverse neuronal apoptosis induced by microwave irradiation. Results show that microwave irradiation causes increment of ASM activation and expression and ASM activation is involved in microwave induced neuronal apoptosis. (authors)

Induction and regulation of tumor necrosis factor-related apoptosis-inducing ligand/Apo-2 ligand-mediated apoptosis in renal cell carcinoma.

Science.gov (United States)

Griffith, Thomas S; Fialkov, Jonathan M; Scott, David L; Azuhata, Takeo; Williams, Richard D; Wall, Nathan R; Altieri, Dario C; Sandler, Anthony D

2002-06-01

The lack of effective therapy for disseminated renal cell carcinoma (RCC) has stimulated the search for novel treatments including immunotherapeutic strategies. However, poor therapeutic responses and marked toxicity associated with immunological agents has limited their use. The tumor necrosis factor family member tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/Apo-2 ligand induces apoptosis in a variety of tumor cell types, while having little cytotoxic activity against normal cells. In this study the activation and regulation of TRAIL-induced apoptosis and TRAIL receptor expression in human RCC cell lines and pathologic specimens was examined. TRAIL induced caspase-mediated apoptotic death of RCC cells with variable sensitivities among the cell lines tested. Compared with TRAIL-sensitive RCC cell lines (A-498, ACHN, and 769-P), the TRAIL-resistant RCC cell line (786-O) expressed lesser amounts of the death-inducing TRAIL receptors, and greater amounts of survivin, an inhibitor of apoptosis. Incubation of 786-O with actinomycin D increased the expression of the death-inducing TRAIL receptors and, concomitantly, decreased the intracellular levels of survivin, resulting in TRAIL-induced apoptotic death. The link between survivin and TRAIL regulation was confirmed when an increase in TRAIL resistance was observed after overexpression of survivin in the TRAIL-sensitive, survivin-negative RCC line A-498. These findings, along with our observation that TRAIL receptors are expressed in RCC tumor tissue, suggest that TRAIL may be useful as a therapeutic agent for RCC and that survivin may partially regulate TRAIL-induced cell death.

On the effect of interaction of molybdenum trioxide and magnesium oxide in water

International Nuclear Information System (INIS)

Bunin, V.M.; Karelin, A.I.; Solov'eva, L.N.

1992-01-01

Interaction of molybdenum trioxide and magnesium oxide in water was studied. It is shown that molybdenum trioxide forms consecutively magnesium molybdate, dimolybdate and magnesium polymolybdates with magnesium oxide

Aniline Induces Oxidative Stress and Apoptosis of Primary Cultured Hepatocytes

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Yue Wang

2016-11-01

Full Text Available The toxicity and carcinogenicity of aniline in humans and animals have been well documented. However, the molecular mechanism involved in aniline-induced liver toxicity and carcinogenesis remains unclear. In our research, primary cultured hepatocytes were exposed to aniline (0, 1.25, 2.50, 5.0 and 10.0 μg/mL for 24 h in the presence or absence of N-acetyl-l-cysteine (NAC. Levels of reactive oxygen species (ROS, malondialdehyde (MDA, and glutathione (GSH, activities of superoxide dismutase (SOD and catalase (CAT, mitochondrial membrane potential, DNA damage, cell viability, and apoptosis were detected. Levels of ROS and MDA were significantly increased and levels of GSH and CAT, activity of SOD, and mitochondrial membrane potential in hepatocytes were significantly decreased by aniline compared with the negative control group. The tail moment and DNA content of the tail in exposed groups were significantly higher than those in the negative control group. Cell viability was reduced and apoptotic death was induced by aniline in a concentration-dependent manner. The phenomena of ROS generation, oxidative damage, loss of mitochondrial membrane potential, DNA damage and apoptosis could be prevented if ROS inhibitor NAC was added. ROS generation is involved in the loss of mitochondrial membrane potential and DNA injury, which may play a role in aniline-induced apoptosis in hepatocytes. Our study provides insight into the mechanism of aniline-induced toxicity and apoptosis of hepatocytes.

Molecular Mechanisms of Particle Ration Induced Apoptosis in Lymphocyte

Science.gov (United States)

Shi, Yufang

Space radiation, composed of high-energy charged nuclei (HZE particles) and protons, has been previously shown to severely impact immune homeostasis in mice. To determine the molecular mechanisms that mediate acute lymphocyte depletion following exposure to HZE particle radiation mice were exposed to particle radiation beams at Brookhaven National Laboratory. We found that mice given whole body 5 6Fe particle irradiation (1GeV /n) had dose-dependent losses in total lymphocyte numbers in the spleen and thymus (using 200, 100 and 50 cGy), with thymocytes being more sensitive than splenocytes. All phenotypic subsets were reduced in number. In general, T cells and B cells were equally sensitive, while CD8+ T cells were more senstive than CD4+ T cells. In the thymus, immature CD4+CD8+ double-positive thymocytes were exquisitely sensitive to radiation-induced losses, single-positive CD4 or CD8 cells were less sensitive, and the least mature double negative cells were resistant. Irradiation of mice deficient in genes encoding essential apoptosis-inducing proteins revealed that the mechanism of lymphocyte depletion is independent of Fas ligand and TRAIL (TNF-ralated apoptosis-inducing ligand), in contrast to γ-radiation-induced lymphocyte losses which require the Fas-FasL pathway. Using inhibitors in vitro, lymphocyte apoptosis induced by HZE particle radiation was found to be caspase dependent, and not involve nitric oxide or oxygen free radicals.

Radiation-induced apoptosis in differentially modulated by PTK inhibitora in K562 cells

International Nuclear Information System (INIS)

Lee, Hyung Sik; Moon, Chang Woo; Hur, Won Joo; Jeong, Su Jin; Jeong Min Ho; Lee, Jeong Hyeon; Lim, Young Jin; Park, Heon Joo

2000-01-01

The effect of PTK inhibitors (herbimycin A and genistein) on the induction of radiation-induced apoptosis in Ph-positive K562 leukemia cell line was investigated. K562 cells in exponential growth phase were irradiated with a linear accelerator at room temperature. For 6 MV X-ray irradiation and drug treatment, cultures were initiated at 2x10 6 cells/ml. The cells were irradiated with 10Gy. Stock solutions of herbimycin A and genistein were prepared in dimethyl sulphoxide (DMSO). After incubation at 37 .deg. for 0-48 h, the extent of apoptosis was determined using agarose gel electrophoresis and TUNEL assay. The progression of cells through the cell cycle after irradiation and drug treatment was also determined with flow cytometry. Western blot analysis was used to monitor bcl-2, bcl-X-L and bax protein levels. Treatment with 10 Gy X-irradiation did not result in the induction of apoptosis. The HMA alone (500 nM) also failed to induce apoptosis. By contrast, incubation of K562 cells with HMA after irradiation resulted in a substantial induction of nuclear condensation and fragmentation by agarose gel electrophoresis and TUNEL assay. Genistein failed to enhance the ability of X-irradiation to induce DNA fragmentation. Enhancement of apoptosis by HMA was not attributable to downregulation of the bcl-2 or bcl-X-L anti-apoptotic proteins. When the cells were irradiated and maintained with HMA, the percentage of cells in G2/M phase decreased to 30-40% at 48 h. On the other hand, cells exposed to 10 Gy X-irradiation alone or maintained with genistein did not show marked cell cycle redistribution. We have shown that nanomolar concentrations of the PTK inhibitor HMA synergize with X-irradiation in inducing the apoptosis in Ph (+) K562 leukemia cell line. While, genistein, a PTK inhibitor which is not selective for p210 bcr/abl failed to enhance the radiation induced apoptosis in K562 cells. It is unlikely that the ability of HMA to enhance apoptosis in K562 cells is

Cytokines effects on radio-induced apoptosis in cortical and hippocampal rat cells in culture

International Nuclear Information System (INIS)

Coffigny, H.; Briot, D.; Le Nin, I.

2000-01-01

In the central nervous system in development the radio-induced cell death occurs mainly by apoptosis. The effects of modulating factors like cytokines were studied on this kind of death. To handle more easily parameters implicated in nerve cell apoptosis, we studied the effects of radiation with a in vitro system. Cells were isolated from rat foetal cortex and hippocampus, two of the major structures implicated in human mental retardation observed after exposition in utero at Hiroshima and Nagasaki. Cortical or hippocampal cells were isolated from 17 day-old rat foetuses by enzymatic and mechanical treatments and irradiated with 0.50 or 1 Gy. The cells from both structures were cultured 1 or 3 days in serum free medium. Cytokines like βNGF, NT3, EGF, βTGF, α and βFGF, IGF I and II, interleukines like Il 1β, Il 2 and IL 6 were added to the medium. In 3 days cortical cell culture, only βFGF increased cell survival with as little as 10 ng/ml. This effect was dose dependent. In hippocampal cell culture, no significant increase of cell survival occurred with 10 ng/ml of any cytokines. In the same system culture with 1 Gy irradiation, the positive or negative effect of the association of βFGF with another cytokine was tested on cell survival. Only the association with EGF induced higher cell survival in cortical cell culture. In hippocampal cell culture where βFGF alone had no effect, the cell survival was not modified by the association. In the same system, the triple association of βFGF-EGF with another cytokine was tested on hippocampal and cortical cell cultures. No significant effect was observed in both cultures but cell survival trented to decrease with βTGF. In order to avoid the mitotic effect of cytokines in the 3 day-old culture, experiments were carried out on 20 hours cell culture, before the end of the first round of the cell cycle, with the selected cytokines (βFGF or βFGF-EGF). Without irradiation, the percentage of cortical cell survival

Matrix metalloproteinase-9 is involved in chronic lymphocytic leukemia cell response to fludarabine and arsenic trioxide.

Directory of Open Access Journals (Sweden)

Irene Amigo-Jiménez

Full Text Available Matrix metalloproteinase-9 (MMP-9 contributes to chronic lymphocytic leukemia (CLL pathology by regulating cell migration and preventing spontaneous apoptosis. It is not known if MMP-9 is involved in CLL cell response to chemotherapy and we address this in the present study, using arsenic trioxide (ATO and fludarabine as examples of cytotoxic drugs.We used primary cells from the peripheral blood of CLL patients and MEC-1 cells stably transfected with an empty vector or a vector containing MMP-9. The effect of ATO and fludarabine was determined by flow cytometry and by the MTT assay. Expression of mRNA was measured by RT-PCR and qPCR. Secreted and cell-bound MMP-9 was analyzed by gelatin zymography and flow cytometry, respectively. Protein expression was analyzed by Western blotting and immunoprecipitation. Statistical analyses were performed using the two-tailed Student's t-test.In response to ATO or fludarabine, CLL cells transcriptionally upregulated MMP-9, preceding the onset of apoptosis. Upregulated MMP-9 primarily localized to the membrane of early apoptotic cells and blocking apoptosis with Z-VAD prevented MMP-9 upregulation, thus linking MMP-9 to the apoptotic process. Culturing CLL cells on MMP-9 or stromal cells induced drug resistance, which was overcome by anti-MMP-9 antibodies. Accordingly, MMP-9-MEC-1 transfectants showed higher viability upon drug treatment than Mock-MEC-1 cells, and this effect was blocked by silencing MMP-9 with specific siRNAs. Following drug exposure, expression of anti-apoptotic proteins (Mcl-1, Bcl-xL, Bcl-2 and the Mcl-1/Bim, Mcl-1/Noxa, Bcl-2/Bax ratios were higher in MMP-9-cells than in Mock-cells. Similar results were obtained upon culturing primary CLL cells on MMP-9.Our study describes for the first time that MMP-9 induces drug resistance by modulating proteins of the Bcl-2 family and upregulating the corresponding anti-apoptotic/pro-apoptotic ratios. This is a novel role for MMP-9 contributing to CLL

Regulation of singlet oxygen-induced apoptosis by cytosolic NADP+-dependent isocitrate dehydrogenase.

Science.gov (United States)

Kim, Sun Yee; Lee, Su Min; Tak, Jean Kyoung; Choi, Kyeong Sook; Kwon, Taeg Kyu; Park, Jeen-Woo

2007-08-01

Singlet oxygen is a highly reactive form of molecular oxygen that may harm living systems by oxidizing critical cellular macromolecules and it also promotes deleterious processes such as cell death. Recently, we demonstrated that the control of redox balance and the cellular defense against oxidative damage are the primary functions of cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDPc) through supplying NADPH for antioxidant systems. In this report, we demonstrate that modulation of IDPc activity in HL-60 cells regulates singlet oxygen-induced apoptosis. When we examined the protective role of IDPc against singlet oxygen-induced apoptosis with HL-60 cells transfected with the cDNA for mouse IDPc in sense and antisense orientations, a clear inverse relationship was observed between the amount of IDPc expressed in target cells and their susceptibility to apoptosis. The results suggest that IDPc plays an important protective role in apoptosis of HL-60 cells induced by singlet oxygen.

Autophagy inhibition enhances apigenin-induced apoptosis in human breast cancer cells

Institute of Scientific and Technical Information of China (English)

Xuchen Cao; Bowen Liu; Wenfeng Cao; Weiran Zhang; Fei Zhang; Hongmeng Zhao; Ran Meng

2013-01-01

Apigenin (4',5,7-trihydroxyflavone) is a member of the flavone subclass of flavonoids present in fruits and vegetables.The involvement of autophagy in the apigenin-induced apoptotic death of human breast cancer cells was investigated.Cell proliferation and viability were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and clonogenic assays.Flow cytometry,fluorescent staining and Western blot analysis were employed to detect apoptosis and autophagy,and the role of autophagy was assessed using autophagy inhibitors.Apigenin dose-and time-dependently repressed the proliferation and clonogenic survival of the human breast cancer T47D and MDA-MB-231 cell lines.The death of T47D and MDA-MB-231 cells was due to apoptosis associated with increased levels of Caspase3,PARP cleavage and Bax/Bcl-2 ratios.The results from flow cytometry and fluorescent staining also verified the occurrence of apoptosis.In addition,the apigenin-treated cells exhibited autophagy,as characterized by the appearance of autophagosomes under fluorescence microscopy and the accumulation of acidic vesicular organelles (AVOs)by flow cytometry.Furthermore,the results of the Western blot analysis revealed that the level of LC3-Ⅱ,the processed form of LC3-Ⅰ,was increased.Treatment with the autophagy inhibitor,3-methyladenine (3-MA),significantly enhanced the apoptosis induced by apigenin,which was accompanied by an increase in the level of PARP cleavage.Similar results were also confirmed by flow cytometry and fluorescence microscopy.These results indicate that apigenin has apoptosis-and autophagy-inducing effects in breast cancer cells.Autophagy plays a cyto-protective role in apigenin-induced apoptosis,and the combination of apigenin and an autophagy inhibitor may be a promising strategy for breast cancer control.

Apoptotic cells can induce non-autonomous apoptosis through the TNF pathway

Science.gov (United States)

Pérez-Garijo, Ainhoa; Fuchs, Yaron; Steller, Hermann

2013-01-01

Apoptotic cells can produce signals to instruct cells in their local environment, including ones that stimulate engulfment and proliferation. We identified a novel mode of communication by which apoptotic cells induce additional apoptosis in the same tissue. Strong induction of apoptosis in one compartment of the Drosophila wing disc causes apoptosis of cells in the other compartment, indicating that dying cells can release long-range death factors. We identified Eiger, the Drosophila tumor necrosis factor (TNF) homolog, as the signal responsible for apoptosis-induced apoptosis (AiA). Eiger is produced in apoptotic cells and, through activation of the c-Jun N-terminal kinase (JNK) pathway, is able to propagate the initial apoptotic stimulus. We also show that during coordinated cell death of hair follicle cells in mice, TNF-α is expressed in apoptotic cells and is required for normal cell death. AiA provides a mechanism to explain cohort behavior of dying cells that is seen both in normal development and under pathological conditions. DOI: http://dx.doi.org/10.7554/eLife.01004.001 PMID:24066226

Suberoyl bis-hydroxamic acid induces p53-dependent apoptosis of MCF-7 breast cancer cells

Institute of Scientific and Technical Information of China (English)

Zhi-gang ZHUANG; Fei FEI; Ying CHEN; Wei JIN

2008-01-01

Aim: To study the effects of suberoyl bis-hydroxamic acid (SBHA), an inhibitor of histone deacetylases, on the apoptosis of MCF-7 breast cancer cells. Meth-ods: Apoptosis in MCF-7 cells induced by SBHA was demonstrated by flow cytometric analysis, morphological observation, and DNA ladder. Mitochondrial membrane potential (△ψm) was measured using the fluorescent probe JC-1. The expressions of p53, p21, Bax, and PUMA were determined using RT-PCR or Western blotting analysis after the MCF-7 cells were treated with SBHA or p53 siRNA. Results: SBHA induced apoptosis in MCF-7 cells. The expressions of p53, p21, Bax, and PUMA were induced, and △ψm collapsed after treatment with SBHA. p53 siRNA abrogated the SBHA-induced apoptosis and the expressions of p53, p21, Bax, and PUMA. Conclusion: The activation of the p53 pathway is involved in SBHA-induced apoptosis in MCF-7 cells.

Arsenic speciation in saliva of acute promyelocytic leukemia patients undergoing arsenic trioxide treatment

OpenAIRE

Chen, Baowei; Cao, Fenglin; Yuan, Chungang; Lu, Xiufen; Shen, Shengwen; Zhou, Jin; Le, X. Chris

2013-01-01

Arsenic trioxide has been successfully used as a therapeutic in the treatment of acute promyelocytic leukemia (APL). Detailed monitoring of the therapeutic arsenic and its metabolites in various accessible specimens of APL patients can contribute to improving treatment efficacy and minimizing arsenic-induced side effects. This article focuses on the determination of arsenic species in saliva samples from APL patients undergoing arsenic treatment. Saliva samples were collected from nine APL pa...

Cell cycle-dependent SUMO-1 conjugation to nuclear mitotic apparatus protein (NuMA)

Energy Technology Data Exchange (ETDEWEB)

Seo, Jae Sung; Kim, Ha Na; Kim, Sun-Jick; Bang, Jiyoung; Kim, Eun-A; Sung, Ki Sa [Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Yoon, Hyun-Joo [TissueGene Inc. 9605 Medical Center Dr., Rockville, MD 20850 (United States); Yoo, Hae Yong [Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Samsung Medical Center, Sungkyunkwan University, Seoul 135-710 (Korea, Republic of); Choi, Cheol Yong, E-mail: choicy@skku.ac.kr [Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2014-01-03

Highlights: •NuMA is modified by SUMO-1 in a cell cycle-dependent manner. •NuMA lysine 1766 is the primary target site for SUMOylation. •SUMOylation-deficient NuMA induces multiple spindle poles during mitosis. •SUMOylated NuMA induces microtubule bundling. -- Abstract: Covalent conjugation of proteins with small ubiquitin-like modifier 1 (SUMO-1) plays a critical role in a variety of cellular functions including cell cycle control, replication, and transcriptional regulation. Nuclear mitotic apparatus protein (NuMA) localizes to spindle poles during mitosis, and is an essential component in the formation and maintenance of mitotic spindle poles. Here we show that NuMA is a target for covalent conjugation to SUMO-1. We find that the lysine 1766 residue is the primary NuMA acceptor site for SUMO-1 conjugation. Interestingly, SUMO modification of endogenous NuMA occurs at the entry into mitosis and this modification is reversed after exiting from mitosis. Knockdown of Ubc9 or forced expression of SENP1 results in impairment of the localization of NuMA to mitotic spindle poles during mitosis. The SUMOylation-deficient NuMA mutant is defective in microtubule bundling, and multiple spindles are induced during mitosis. The mitosis-dependent dynamic SUMO-1 modification of NuMA might contribute to NuMA-mediated formation and maintenance of mitotic spindle poles during mitosis.

DMPD: Pathogen-induced apoptosis of macrophages: a common end for different pathogenicstrategies. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 11207583 Pathogen-induced apoptosis of macrophages: a common end for different path...ml) Show Pathogen-induced apoptosis of macrophages: a common end for different pathogenicstrategies. PubmedI...D 11207583 Title Pathogen-induced apoptosis of macrophages: a common end for diff

Resveratrol and arsenic trioxide act synergistically to kill tumor cells in vitro and in vivo.

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Xiao-Yan Zhao

Full Text Available BACKGROUND AND AIMS: Arsenic trioxide (As2O3, which used as an effective agent in the treatment of leukaemia and other solid tumors, is largely limited by its toxicity. QT prolongation, torsades de pointes and sudden heart death have been implicated in the cardiotoxicity of As2O3. The present study was designed to explore whether the combination of As2O3 and resveratrol could generate a more powerful anti-cancer effect both in vitro and in vivo. MATERIALS AND METHODS: MTT assay was performed to assess the proliferation of Hela, MCF-7 and NB4 cells. Isobolographic analysis was used to evaluate combination index values from cell viability data. The apoptosis and the cellular reactive oxygen species (ROS level were assessed by fluorescent microscopy and flow cytometry separately in vitro. The effect of As2O3, alone and in combination with resveratrol on Hela tumor growth in an orthotopic nude mouse model was also investigated. The tumor volume and the immunohistochemical analysis of CD31, CD34 and VEGF were determined. RESULTS: Resveratrol dramatically enhanced the anti-cancer effect induced by As2O3 in vitro. In addition, isobolographic analysis further demonstrated that As2O3 and resveratrol generated a synergistic action. More apoptosis and ROS generation were observed in the combination treatment group. Similar synergistic effects were found in nude mice in vivo. The combination of As2O3 and resveratrol dramatically suppressed both tumor growth and angiogenesis in nude mice. CONCLUSIONS: Combining As2O3 with resveratrol would be a novel strategy to treat cancer in clinical practice.

Drosophila MOF regulates DIAP1 and induces apoptosis in a JNK dependent pathway.

Science.gov (United States)

Pushpavalli, Sreerangam N C V L; Sarkar, Arpita; Ramaiah, M Janaki; Koteswara Rao, G; Bag, Indira; Bhadra, Utpal; Pal-Bhadra, Manika

2016-03-01

Histone modulations have been implicated in various cellular and developmental processes where in Drosophila Mof is involved in acetylation of H4K16. Reduction in the size of larval imaginal discs is observed in the null mutants of mof with increased apoptosis. Deficiency involving Hid, Reaper and Grim [H99] alleviated mof (RNAi) induced apoptosis in the eye discs. mof (RNAi) induced apoptosis leads to activation of caspases which is suppressed by over expression of caspase inhibitors like P35 and Diap1 clearly depicting the role of caspases in programmed cell death. Also apoptosis induced by knockdown of mof is rescued by JNK mutants of bsk and tak1 indicating the role of JNK in mof (RNAi) induced apoptosis. The adult eye ablation phenotype produced by ectopic expression of Hid, Rpr and Grim, was restored by over expression of Mof. Accumulation of Mof at the Diap1 promoter 800 bp upstream of the transcription start site in wild type larvae is significantly higher (up to twofolds) compared to mof (1) mutants. This enrichment coincides with modification of histone H4K16Ac indicating an induction of direct transcriptional up regulation of Diap1 by Mof. Based on these results we propose that apoptosis triggered by mof (RNAi) proceeds through a caspase-dependent and JNK mediated pathway.

LR-90 prevents methylglyoxal-induced oxidative stress and apoptosis in human endothelial cells

Science.gov (United States)

Figarola, James L.; Singhal, Jyotsana; Rahbar, Samuel; Awasthi, Sanjay

2014-01-01

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound known to induce cellular injury and cytoxicity, including apoptosis in vascular cells. Vascular endothelial cell apoptosis has been implicated in the pathophysiology and progression of atherosclerosis. We investigated whether the advanced glycation end-product inhibitor LR-90 could prevent MGO-induced apoptosis in human umbilical vascular endothelial cells (HUVECs). HUVECs were pre-treated with LR-90 and then stimulated with MGO. Cell morphology, cytotoxicity and apoptosis were evaluated by light microscopy, MTT assay, and Annexin V-FITC and propidium iodide double staining, respectively. Levels of Bax, Bcl-2, cytochrome c, mitogen-activated protein kinases (MAPKs) and caspase activities were assessed by Western blotting. Reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) were measured with fluorescent probes. LR-90 dose-dependently prevented MGO-associated HUVEC cytotoxicity and apoptotic biochemical changes such as loss of MMP, increased Bax/Bcl-2 protein ratio, mitochondrial cytochrome c release and activation of caspase-3 and 9. Additionally, LR-90 blocked intracellular ROS formation and MAPK (p44/p42, p38, JNK) activation, though the latter seem to be not directly involved in MGO-induced HUVEC apoptosis. LR-90 prevents MGO-induced HUVEC apoptosis by inhibiting ROS and associated mitochondrial-dependent apoptotic signaling cascades, suggesting that LR-90 possess cytoprotective ability which could be beneficial in prevention of diabetic related-atherosclerosis. PMID:24615331

Programming voltage reduction in phase change memory cells with tungsten trioxide bottom heating layer/electrode

International Nuclear Information System (INIS)

Rao Feng; Song Zhitang; Gong Yuefeng; Wu Liangcai; Feng Songlin; Chen, Bomy

2008-01-01

A phase change memory cell with tungsten trioxide bottom heating layer/electrode is investigated. The crystalline tungsten trioxide heating layer promotes the temperature rise in the Ge 2 Sb 2 Te 5 layer which causes the reduction in the reset voltage compared to a conventional phase change memory cell. Theoretical thermal simulation and calculation for the reset process are applied to understand the thermal effect of the tungsten trioxide heating layer/electrode. The improvement in thermal efficiency of the PCM cell mainly originates from the low thermal conductivity of the crystalline tungsten trioxide material.

Toll-like receptor 9 is required for opioid-induced microglia apoptosis.

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Lei He

2011-04-01

Full Text Available Opioids have been widely applied in clinics as one of the most potent pain relievers for centuries, but their abuse has deleterious physiological effects beyond addiction. However, the underlying mechanism by which microglia in response to opioids remains largely unknown. Here we show that morphine induces the expression of Toll-like receptor 9 (TLR9, a key mediator of innate immunity and inflammation. Interestingly, TLR9 deficiency significantly inhibited morphine-induced apoptosis in microglia. Similar results were obtained when endogenous TLR9 expression was suppressed by the TLR9 inhibitor CpGODN. Inhibition of p38 MAPK by its specific inhibitor SB203580 attenuated morphine-induced microglia apoptosis in wild type microglia. Morphine caused a dramatic decrease in Bcl-2 level but increase in Bax level in wild type microglia, but not in TLR9 deficient microglia. In addition, morphine treatment failed to induce an increased levels of phosphorylated p38 MAPK and MAP kinase kinase 3/6 (MKK3/6, the upstream MAPK kinase of p38 MAPK, in either TLR9 deficient or µ-opioid receptor (µOR deficient primary microglia, suggesting an involvement of MAPK and µOR in morphine-mediated TLR9 signaling. Moreover, morphine-induced TLR9 expression and microglia apoptosis appears to require μOR. Collectively, these results reveal that opioids prime microglia to undergo apoptosis through TLR9 and µOR as well. Taken together, our data suggest that inhibition of TLR9 and/or blockage of µOR is capable of preventing opioid-induced brain damage.

The correlation between spontaneous and radiation-induced apoptosis in T3B bladder cancer (histological grade G3), and the precedence between the two kinds of apoptosis for predicting clinical prognosis

International Nuclear Information System (INIS)

Harada, Satoshi; Sato, Ryuichi; Nakamura, Ryuji; Oikawa, Hiroshi; Oikawa, Hirobumi; Ohgi, Shie; Tamakawa, Yoshiharu; Yanagisawa, Toru

2000-01-01

Purpose: The correlation between the frequency of spontaneous and radiation-induced apoptosis, and the precedence between those for predicting prognosis were studied at clinical level. Methods and Materials: Twenty-one patients (mean age, 65.8 years; 16 men and 5 women) with bladder cancer (transitional cell carcinoma Grade 3, T3bN0M0, Stage IIIb) underwent intraoperative radiotherapy: single 30-Gy 12-MV electron beam irradiation to bladder, followed by total cystectomy 6 h after irradiation. The specimens of pretreatment and irradiated bladder cancer were assayed for apoptosis, using TUNEL staining with counter staining of hematoxylin. The apoptotic index (AI) was calculated by dividing the number of apoptotic cells by the total number of cells and multiplying by 100. The Pearson's linear fitting was used to test the correlation between spontaneous and radiation-induced apoptosis. The Kaplan-Meier product-limit estimation was used for overall survival (OS) and freedom from recurrence (FFR). The precedence between spontaneous and radiation-induced apoptosis for predicting the clinical prognosis was estimated using the proportional hazard regression. Results: The mean AI of spontaneous and radiation-induced apoptosis was 1.18 ± 0.16 and 2.63 ± 0.45, respectively, which was significantly different. There was strong correlation between spontaneous and radiation-induced apoptosis (r 2 = 0.864, adjusted r 2 = 0.857). Radiation-induced apoptosis was estimated by equitation: y (radiation-induced apoptosis) = 2.67 x (spontaneous apoptosis) -0.52. However, the proportional hazard regression test indicated that only spontaneous apoptosis was significant for predicting OS and FFR (vertical bar t vertical bar > 0.2), but radiation-induced apoptosis was not. Conclusion: Estimating AI in radiation-induced apoptosis from AI in spontaneous apoptosis is possible. However, spontaneous apoptosis is more accurate in predicting clinical prognosis

Nutrient Availability Alters the Effect of Autophagy on Sulindac Sulfide-Induced Colon Cancer Cell Apoptosis

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Shiun-Kwei Chiou

2012-01-01

Full Text Available Autophagy is a catabolic process by which a cell degrades its intracellular materials to replenish itself. Induction of autophagy under various cellular stress stimuli can lead to either cell survival or cell death via apoptotic and/or autophagic (nonapoptotic pathways. The NSAID sulindac sulfide induces apoptosis in colon cancer cells. Here, we show that inhibition of autophagy under serum-deprived conditions resulted in significant reductions of sulindac sulfide-induced apoptosis in HT-29 colon cancer cells. In contrast, inhibition of autophagy under conditions where serum is available significantly increased sulindac sulfide-induced apoptosis in HT-29 cells. We previously showed that the apoptosis inhibitor, survivin, plays a role in regulating NSAID-induced apoptosis and autophagic cell death. Here, we show that survivin protein half-life is increased in the presence of autophagy inhibitors under serum-deprived conditions, but not under conditions when serum is available. Thus, the increased levels of survivin may be a factor contributing to inhibition of sulindac sulfide-induced apoptosis under serum-deprived conditions. These results suggest that whether a cell lives or dies due to autophagy induction depends on the balance of factors that regulate both autophagic and apoptotic processes.

Herbal medicine as inducers of apoptosis in cancer treatment.

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Safarzadeh, Elham; Sandoghchian Shotorbani, Siamak; Baradaran, Behzad

2014-10-01

Cancer is uncontrolled growth of abnormal cells in the body. Nowadays, cancer is considered as a human tragedy and one of the most prevalent diseases in the wide, and its mortality resulting from cancer is being increased. It seems necessary to identify new strategies to prevent and treat such a deadly disease. Control survival and death of cancerous cell are important strategies in the management and therapy of cancer. Anticancer agents should kill the cancerous cell with the minimal side effect on normal cells that is possible through the induction of apoptosis. Apoptosis is known as programmed cell death in both normal and damaged tissues. This process includes some morphologically changes in cells such as rapid condensation and budding of the cell, formation of membrane-enclosed apoptotic bodies with well-preserved organelles. Induction of apoptosis is one of the most important markers of cytotoxic antitumor agents. Some natural compounds including plants induce apoptotic pathways that are blocked in cancer cells through various mechanisms in cancer cells. Multiple surveys reported that people with cancer commonly use herbs or herbal products. Vinca Alkaloids, Texans, podo phyllotoxin, Camptothecins have been clinically used as Plant derived anticancer agents. The present review summarizes the literature published so far regarding herbal medicine used as inducers of apoptosis in cancer.

Valsartan protects HK-2 cells from contrast media-induced apoptosis by inhibiting endoplasmic reticulum stress.

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Peng, Ping-An; Wang, Le; Ma, Qian; Xin, Yi; Zhang, Ou; Han, Hong-Ya; Liu, Xiao-Li; Ji, Qing-Wei; Zhou, Yu-Jie; Zhao, Ying-Xin

2015-12-01

Contrast-induced acute kidney injury (CI-AKI) is associated with increasing in-hospital and long-term adverse clinical outcomes in high-risk patients undergoing percutaneous coronary intervention (PCI). Contrast media (CM)-induced renal tubular cell apoptosis is reported to participate in this process by activating endoplasmic reticulum (ER) stress. An angiotensin II type 1 receptor (AT1R) antagonist can alleviate ER stress-induced renal apoptosis in streptozotocin (STZ)-induced diabetic mice and can reduce CM-induced renal apoptosis by reducing oxidative stress and reversing the enhancement of bax mRNA and the reduction of bcl-2 mRNA, but the effect of the AT1R blocker on ER stress in the pathogenesis of CI-AKI is still unknown. In this study, we explored the effect of valsartan on meglumine diatrizoate-induced human renal tubular cell apoptosis by measuring changes in ER stress-related biomarkers. The results showed that meglumine diatrizoate caused significant cell apoptosis by up-regulating the expression of ER stress markers, including glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), CCAAT/enhancer-binding protein-homologous protein (CHOP) and caspase 12, in a time- and dose-dependent manner, which could be alleviated by preincubation with valsartan. In conclusion, valsartan had a potential nephroprotective effect on meglumine diatrizoate-induced renal cell apoptosis by inhibiting ER stress. © 2015 International Federation for Cell Biology.

Morphine Protects Spinal Cord Astrocytes from Glutamate-Induced Apoptosis via Reducing Endoplasmic Reticulum Stress

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Chao Zhang

2016-10-01

Full Text Available Glutamate is not only a neurotransmitter but also an important neurotoxin in central nervous system (CNS. Chronic elevation of glutamate induces both neuronal and glial cell apoptosis. However, its effect on astrocytes is complex and still remains unclear. In this study, we investigated whether morphine, a common opioid ligand, could affect glutamate-induced apoptosis in astrocytes. Primary cultured astrocytes were incubated with glutamate in the presence/absence of morphine. It was found that morphine could reduce glutamate-induced apoptosis of astrocytes. Furthermore, glutamate activated Ca2+ release, thereby inducing endoplasmic reticulum (ER stress in astrocytes, while morphine attenuated this deleterious effect. Using siRNA to reduce the expression of κ-opioid receptor, morphine could not effectively inhibit glutamate-stimulated Ca2+ release in astrocytes, the protective effect of morphine on glutamate-injured astrocytes was also suppressed. These results suggested that morphine could protect astrocytes from glutamate-induced apoptosis via reducing Ca2+ overload and ER stress pathways. In conclusion, this study indicated that excitotoxicity participated in the glutamate mediated apoptosis in astrocytes, while morphine attenuated this deleterious effect via regulating Ca2+ release and ER stress.

Radiation-induced apoptosis of lymphocytes in peripheral blood

International Nuclear Information System (INIS)

Oh, Yoon Kyeong; Lee, Tae Bum; Nam, Taek Keun; Kee, Keun Hong; Choi, Cheol Hee

2003-01-01

This study quantitatively evaluated the apoptosis in human peripheral blood lymphocytes using flow cytometry, and investigated the possibility of using this method, with a small amount of blood, and the time and dose dependence of radiation-induced apoptosis. Peripheral blood lymphocytes were isolated from the heparinized venous blood of 11 healthy volunteers, 8 men and 3 women, with each 10 ml of blood being divided into 15 samples. The blood lymphocytes were irradiated using a linear accelerator at a dose rate of 2.4 Gy/min, to deliver doses of 0.5, 1, 2 and 5 Gy. The control samples, and irradiated cells, were maintained in culture medium for 24, 48 and 72 hours following the irradiation. The number of apoptotic cells after the in vitro X-irradiation was measured by flow cytometry after incubation periods of 24, 48 and 72 hours. We also observed the apoptotic cells using a DNA fragmentation assay and electron microscopy. The rate of spontaneous apoptosis increased in relation to the time interval following irradiation (1.761±0.161, 3.563±0.564, 11.098±2.849, at 24, 48, and 72 hours). The apoptotic cells also increased in the samples irradiated with 0.5, 1, 2 and 5 Gy, in a radiation dose and time interval after irradiation manner, with the apoptosis being too great at 72 hours after irradiation. The dose-response curves were characterized by an initial steep increase in the number of apoptotic cells for irradiation doses below 2 Gy, with a flattening of the curves as the dose approached towards 5 Gy. The flow cytometric assay technique yielded adequate data, and required less than 1 mL of blood. The time and dose dependence of the radiation-induced apoptosis, was also shown. It is suggested that the adequate time interval required for the evaluation of apoptosis would be 24 to 48 hours after blood sampling

The potential DNA toxic changes among workers exposed to antimony trioxide.

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El Shanawany, Safaa; Foda, Nermine; Hashad, Doaa I; Salama, Naglaa; Sobh, Zahraa

2017-05-01

Occupational exposure to antimony has gained much interest when specific toxic effects were noticed among workers processing antimony. Thus, the aim of the present work was to investigate the potential DNA oxidative damage occurring among Egyptian workers occupationally exposed to antimony trioxide. The study was conducted on 25 subjects exposed to antimony trioxide while working in the polymerization process of polyester in Misrayon and Polyester Fiber Company, KafrEldawwar, Beheira, Egypt. Urinary antimony levels were assessed using inductive coupled plasma-optical emission spectrometry (ICP-OES) and considered as a biological exposure index. DNA damage and total oxidant capacity (TOC) were assessed using ELISA. DNA damage was detected in the form of increased apurinic/apyrimidinic (AP) sites among antimony trioxide-exposed workers compared to control subjects, but it could not be explained by oxidative mechanisms due to lack of significant correlation between DNA damage and measured TOC. Antimony trioxide might have a genotoxic impact on occupationally exposed workers which could not be attributed to oxidative stress in the studied cases.

CYTOGENETICS EFFECTS INDUCED BY NITRATE OF LEAD ON MITOTIC DIVISION AT ALLIUM CEPA L.

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Silvica Padureanu

2005-01-01

The paper presents the influence of nitrate of lead upon the mitotic division of Allium cepa L. The treatment with nitrate of lead has determined the lessening of the mitotic index and the chromosomial mutations. Also nitrate of lead determined in little proportion cells autopoliploid. The experiment prowed that nitrate of lead, known as a polluting agent has a mutagenic potential on the plants.

Aminomethylphosphonic Acid and Methoxyacetic Acid Induce Apoptosis in Prostate Cancer Cells

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Keshab R. Parajuli

2015-05-01

Full Text Available Aminomethylphosphonic acid (AMPA and its parent compound herbicide glyphosate are analogs to glycine, which have been reported to inhibit proliferation and promote apoptosis of cancer cells, but not normal cells. Methoxyacetic acid (MAA is the active metabolite of ester phthalates widely used in industry as gelling, viscosity and stabilizer; its exposure is associated with developmental and reproductive toxicities in both rodents and humans. MAA has been reported to suppress prostate cancer cell growth by inducing growth arrest and apoptosis. However, it is unknown whether AMPA and MAA can inhibit cancer cell growth. In this study, we found that AMPA and MAA inhibited cell growth in prostate cancer cell lines (LNCaP, C4-2B, PC-3 and DU-145 through induction of apoptosis and cell cycle arrest at the G1 phase. Importantly, the AMPA-induced apoptosis was potentiated with the addition of MAA, which was due to downregulation of the anti-apoptotic gene baculoviral inhibitor of apoptosis protein repeat containing 2 (BIRC2, leading to activation of caspases 7 and 3. These results demonstrate that the combination of AMPA and MAA can promote the apoptosis of prostate cancer cells, suggesting that they can be used as potential therapeutic drugs in the treatment of prostate cancer.

Aminomethylphosphonic acid and methoxyacetic acid induce apoptosis in prostate cancer cells.

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Parajuli, Keshab R; Zhang, Qiuyang; Liu, Sen; You, Zongbing

2015-05-22

Aminomethylphosphonic acid (AMPA) and its parent compound herbicide glyphosate are analogs to glycine, which have been reported to inhibit proliferation and promote apoptosis of cancer cells, but not normal cells. Methoxyacetic acid (MAA) is the active metabolite of ester phthalates widely used in industry as gelling, viscosity and stabilizer; its exposure is associated with developmental and reproductive toxicities in both rodents and humans. MAA has been reported to suppress prostate cancer cell growth by inducing growth arrest and apoptosis. However, it is unknown whether AMPA and MAA can inhibit cancer cell growth. In this study, we found that AMPA and MAA inhibited cell growth in prostate cancer cell lines (LNCaP, C4-2B, PC-3 and DU-145) through induction of apoptosis and cell cycle arrest at the G1 phase. Importantly, the AMPA-induced apoptosis was potentiated with the addition of MAA, which was due to downregulation of the anti-apoptotic gene baculoviral inhibitor of apoptosis protein repeat containing 2 (BIRC2), leading to activation of caspases 7 and 3. These results demonstrate that the combination of AMPA and MAA can promote the apoptosis of prostate cancer cells, suggesting that they can be used as potential therapeutic drugs in the treatment of prostate cancer.

The antitumor effect of arsenic trioxide on hepatocellular carcinoma is enhanced by andrographolide.

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Duan, Xuhua; Li, Tengfei; Han, Xinwei; Ren, Jianzhuang; Chen, Pengfei; Li, Hao; Gong, Shaojun

2017-10-31

High concentrations of arsenic trioxide (As 2 O 3 ) are used to treat acute promyelocytic leukemia and solid tumors, with negative side effects to normal cells. Andrographolide is a traditional Chinese medicine that exerts anti-cancer, anti-inflammatory, anti-virus, and anti-diabetic effects. Here, we tested the effects of combined andrographolide with As 2 O 3 against hepatocellular carcinoma (HCC). We found that by increasing apoptosis, andrographolide synergistically enhanced the anti-tumor effects of As2O3 in HepG2 cells in vitro and in vivo . Furthermore, results from our microarray assays and experiments with mouse xenografts showed that EphB4 was downregulated by the combination of As 2 O 3 plus andrographolide. These findings suggest that the combination of andrographolide and As 2 O 3 could yield therapeutic benefits in the treatment of HCC.

Gallic acid induces apoptosis in EGFR-mutant non-small cell lung cancers by accelerating EGFR turnover.

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Nam, Boas; Rho, Jin Kyung; Shin, Dong-Myung; Son, Jaekyoung

2016-10-01

Gallic acid is a common botanic phenolic compound, which is present in plants and foods worldwide. Gallic acid is implicated in various biological processes such as cell growth and apoptosis. Indeed, gallic acid has been shown to induce apoptosis in many cancer types. However, the molecular mechanisms of gallic acid-induced apoptosis in cancer, particularly lung cancer, are still unclear. Here, we report that gallic acid induces apoptosis in EGFR-mutant non-small cell lung cancer (NSCLC) cells, but not in EGFR-WT NSCLC cells. Treatment with gallic acid resulted in a significant reduction in proliferation and induction of apoptosis, only in EGFR-mutant NSCLC cells. Interestingly, treatment with gallic acid led to a robust decrease in EGFR levels, which is critical for NSCLC survival. Treatment with gallic acid had no significant effect on transcription, but induced EGFR turnover. Indeed, treatment with a proteasome inhibitor dramatically reversed gallic acid-induced EGFR downregulation. Moreover, treatment with gallic acid induced EGFR turnover leading to apoptosis in EGFR-TKI (tyrosine kinase inhibitor)-resistant cell lines, which are dependent on EGFR signaling for survival. Thus, these studies suggest that gallic acid can induce apoptosis in EGFR-dependent lung cancers that are dependent on EGFR for growth and survival via acceleration of EGFR turnover. Copyright © 2016 Elsevier Ltd. All rights reserved.

Relationship between radiation induced activation of DNA repair genes and radiation induced apoptosis in human cell line A431

International Nuclear Information System (INIS)

Bom, Hee Seung; Min, Jung Jun; Kim, Kyung Keun; Choi, Keun Hee

2000-01-01

The purpose of this study was to evaluate the relationship between radiation-induced acivation of DNA repair genes and radiation induced apoptosis in A431 cell line. Five and 25 Gys of gamma radiation were given to A431 cells by a Cs-137 cell irradiator. Apoptosis was evaluated by flow cytometry using annexin V-fluorescein isothiocyanate and propidium iodide staining. The expression of DNA repair genes was evaluated by both Northern and Western blot analyses. The number of apoptotic cells increased with the increased radiation dose. It increased most significantly at 12 hours after irradiation. Expression of p53, p21, and ℎRAD50 reached the highest level at 12 hours after 5 Gy irradiation. In response to 25 Gy irradiation, ℎRAD50 and p21 were expressed maximally at 12 hours, but p53 and GADD45 genes showed the highest expression level after 12 hours. Induction of apoptosis and DNA repair by ionizing radiation were closely correlated. The peak time of inducing apoptosis and DNA repair was 12 hours in this study model. ℎRAD50, a recently discovered DNA repair gene, was also associated with radiation-induced apoptosis.=20

GSK-3beta inhibition enhances sorafenib-induced apoptosis in melanoma cell lines.

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Panka, David J; Cho, Daniel C; Atkins, Michael B; Mier, James W

2008-01-11

Glycogen synthase kinase-3beta (GSK-3beta) can participate in the induction of apoptosis or, alternatively, provide a survival signal that minimizes cellular injury. We previously demonstrated that the multikinase inhibitor sorafenib induces apoptosis in melanoma cell lines. In this report, we show that sorafenib activates GSK-3beta in multiple subcellular compartments and that this activation undermines the lethality of the drug. Pharmacologic inhibition and/or down-modulation of the kinase enhances sorafenib-induced apoptosis as determined by propidium iodide staining and by assessing the mitochondrial release of apoptosis-inducing factor and Smac/DIABLO. Conversely, the forced expression of a constitutively active form of the enzyme (GSK-3beta(S9A)) protects the cells from the apoptotic effects of the drug. This protective effect is associated with a marked increase in basal levels of Bcl-2, Bcl-x(L), and survivin and a diminution in the degree to which these anti-apoptotic proteins are down-modulated by sorafenib exposure. Sorafenib down-modulates the pro-apoptotic Bcl-2 family member Noxa in cells with high constitutive GSK-3beta activity. Pharmacologic inhibition of GSK-3beta prevents the disappearance of Noxa induced by sorafenib and enhances the down-modulation of Mcl-1. Down-modulation of Noxa largely eliminates the enhancing effect of GSK-3 inhibition on sorafenib-induced apoptosis. These data provide a strong rationale for the use of GSK-3beta inhibitors as adjuncts to sorafenib treatment and suggest that preservation of Noxa may contribute to their efficacy.

UVC-induced apoptosis in Dubca cells is independent of JNK activation and p53Ser-15 phosphorylation

International Nuclear Information System (INIS)

Chathoth, Shahanas; Thayyullathil, Faisal; Hago, Abdulkader; Shahin, Allen; Patel, Mahendra; Galadari, Sehamuddin

2009-01-01

Ultraviolet C (UVC) irradiation in mammalian cell lines activates a complex signaling network that leads to apoptosis. By using Dubca cells as a model system, we report the presence of a UVC-induced apoptotic pathway that is independent of c-Jun N-terminal kinases (JNKs) activation and p53 phosphorylation at Ser 15 . Irradiation of Dubca cells with UVC results in a rapid JNK activation and phosphorylation of its downstream target c-Jun, as well as, phosphorylation of activating transcription factor 2 (ATF2). Pre-treatment with JNK inhibitor, SP600125, inhibited UVC-induced c-Jun phosphorylation without preventing UVC-induced apoptosis. Similarly, inhibition of UVC-induced p53 phosphorylation did not prevent Dubca cell apoptosis, suggesting that p53 Ser-15 phosphorylation is not associated with UVC-induced apoptosis signaling. The pan-caspase inhibitor z-VAD-fmk inhibited UVC-induced PARP cleavage, DNA fragmentation, and ultimately apoptosis of Dubca cells. Altogether, our study clearly indicates that UVC-induced apoptosis is independent of JNK and p53 activation in Dubca cells, rather, it is mediated through a caspase dependent pathway. Our findings are not in line with the ascribed critical role for JNKs activation, and downstream phosphorylation of targets such as c-Jun and ATF2 in UVC-induced apoptosis.

Novel TRAIL sensitizer Taraxacum officinale F.H. Wigg enhances TRAIL-induced apoptosis in Huh7 cells.

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Yoon, Ji-Yong; Cho, Hyun-Soo; Lee, Jeong-Ju; Lee, Hyo-Jung; Jun, Soo Young; Lee, Jae-Hye; Song, Hyuk-Hwan; Choi, SangHo; Saloura, Vassiliki; Park, Choon Gil; Kim, Cheol-Hee; Kim, Nam-Soon

2016-04-01

TRAIL (TNF-related apoptosis inducing ligand) is a promising anti-cancer drug target that selectively induces apoptosis in cancer cells. However, many cancer cells are resistant to TRAIL-induced apoptosis. Therefore, reversing TRAIL resistance is an important step for the development of effective TRAIL-based anti-cancer therapies. We previously reported that knockdown of the TOR signaling pathway regulator-like (TIPRL) protein caused TRAIL-induced apoptosis by activation of the MKK7-c-Jun N-terminal Kinase (JNK) pathway through disruption of the MKK7-TIPRL interaction. Here, we identified Taraxacum officinale F.H. Wigg (TO) as a novel TRAIL sensitizer from a set of 500 natural products using an ELISA system and validated its activity by GST pull-down analysis. Furthermore, combination treatment of Huh7 cells with TRAIL and TO resulted in TRAIL-induced apoptosis mediated through inhibition of the MKK7-TIPRL interaction and subsequent activation of MKK7-JNK phosphorylation. Interestingly, HPLC analysis identified chicoric acid as a major component of the TO extract, and combination treatment with chicoric acid and TRAIL induced TRAIL-induced cell apoptosis via JNK activation due to inhibition of the MKK7-TIPRL interaction. Our results suggest that TO plays an important role in TRAIL-induced apoptosis, and further functional studies are warranted to confirm the importance of TO as a novel TRAIL sensitizer for cancer therapy. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Radiation-induced apoptosis in the neonatal and adult rat spinal cord.

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Li, Y Q; Wong, C S

2000-09-01

This study was designed to characterize radiation-induced apoptosis in the spinal cord of the neonatal and young adult rat. Spinal cords (C2-T2) of 1-, 2- and 10-week-old rats were irradiated with a single dose of 8, 18 or 22 Gy. Apoptosis was assessed histologically according to its specific morphological features or by using the TUNEL assay. Cell proliferation was assessed immunohistochemically using BrdU. Identities of cell types undergoing apoptosis were assessed using immunohistochemistry or in situ hybridization using markers for neurons, glial progenitor cells, microglia, oligodendrocytes and astrocytes. The time course of radiation-induced apoptosis in 1- or 2-week-old rat spinal cord was similar to that in the young adult rat spinal cord. A peak response was observed at about 8 h after irradiation, and the apoptosis index returned to the levels in nonirradiated spinal cords at 24 h. The neonatal rat spinal cord demonstrated increased apoptosis compared to the adult. Values for total yield of apoptosis over 24 h induced by 8 Gy in the neonatal rat spinal cord were significantly greater than that in the adult. Immunohistochemistry studies using Leu7, galactocerebroside, Rip and adenomatous polyposis coli tumor suppressor protein indicated that most apoptotic cells were cells of the oligodendroglial lineage regardless of the age of the animal. No evidence of Gfap or factor VIII-related antigen-positive apoptotic cells was observed, and there was a small number of apoptotic microglial cells (lectin-Rca1 positive) in the neonatal and adult rat spinal cord. In the neonatal but not adult rat spinal cord, about 10% of the apoptotic cells appeared to be neurons and were immunoreactive for synaptophysin. Labeling indices (LI) for BrdU in nonirradiated 1- and 2-week-old rat spinal cord were 20.0 and 16.3%, respectively, significantly greater than the LI of 1.0% in the 10-week-old rat spinal cord. At 8 h after a single dose of 8 Gy, 13.4% of the apoptotic cells were

TGEV nucleocapsid protein induces cell cycle arrest and apoptosis through activation of p53 signaling

International Nuclear Information System (INIS)

Ding, Li; Huang, Yong; Du, Qian; Dong, Feng; Zhao, Xiaomin; Zhang, Wenlong; Xu, Xingang; Tong, Dewen

2014-01-01

Highlights: • TGEV N protein reduces cell viability by inducing cell cycle arrest and apoptosis. • TGEV N protein induces cell cycle arrest and apoptosis by regulating p53 signaling. • TGEV N protein plays important roles in TGEV-induced cell cycle arrest and apoptosis. - Abstract: Our previous studies showed that TGEV infection could induce cell cycle arrest and apoptosis via activation of p53 signaling in cultured host cells. However, it is unclear which viral gene causes these effects. In this study, we investigated the effects of TGEV nucleocapsid (N) protein on PK-15 cells. We found that TGEV N protein suppressed cell proliferation by causing cell cycle arrest at the S and G2/M phases and apoptosis. Characterization of various cellular proteins that are involved in regulating cell cycle progression demonstrated that the expression of N gene resulted in an accumulation of p53 and p21, which suppressed cyclin B1, cdc2 and cdk2 expression. Moreover, the expression of TGEV N gene promoted translocation of Bax to mitochondria, which in turn caused the release of cytochrome c, followed by activation of caspase-3, resulting in cell apoptosis in the transfected PK-15 cells following cell cycle arrest. Further studies showed that p53 inhibitor attenuated TGEV N protein induced cell cycle arrest at S and G2/M phases and apoptosis through reversing the expression changes of cdc2, cdk2 and cyclin B1 and the translocation changes of Bax and cytochrome c induced by TGEV N protein. Taken together, these results demonstrated that TGEV N protein might play an important role in TGEV infection-induced p53 activation and cell cycle arrest at the S and G2/M phases and apoptosis occurrence

Study on apoptosis of prostate cancer cell induced by 125I seed irradiation

International Nuclear Information System (INIS)

Liao Anyan; Wang Junjie; Wang Jidong; Zhuang Hongqing; Zhao Yong

2007-01-01

Objective: To explore the mechanism of apoptosis induced by 125 I seed irradiation on PC3 cells. Methods: Human prostate cancer cell line PC3 was treated by irradiation of 125 I (2.77 cGy/h) with various dose. Agarose gel electrophoresis of DNA and flows cytometry were used to detect the apoptosis of PC3 cells and indirect immunofluorescence assay was used to detect the expression of Bcl-2. The activity of Caspase-3 was measured by Caspase Colorimetric Assay Kits. Results: Apoptosis of PC3 cells could be efficiently induced by 125 I seed irradiation. The apoptotic peaks were found by flow cytometry and DNA ladder appeared on 1.8% agarose gel. The activity of Caspase-3 on PC3 cells treated by 125 I seed irradiation was not changed significantly. Bcl-2 gene expression was down-regulated with the sample concentration increased. Conclusion: 125 I irradiation can induce the apoptosis of PC3 cells and the mechanism of apoptosis is related with down regulation of Bcl-2 gene expression and is not related with Caspase-3 activity. (authors)

Chlorella vulgaris triggers apoptosis in hepatocarcinogenesis-induced rats*

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Mohd Azamai, Emey Suhana; Sulaiman, Suhaniza; Mohd Habib, Shafina Hanim; Looi, Mee Lee; Das, Srijit; Abdul Hamid, Nor Aini; Wan Ngah, Wan Zurinah; Mohd Yusof, Yasmin Anum

2009-01-01

Chlorella vulgaris (CV) has been reported to have antioxidant and anticancer properties. We evaluated the effect of CV on apoptotic regulator protein expression in liver cancer-induced rats. Male Wistar rats (200~250 g) were divided into eight groups: control group (normal diet), CDE group (choline deficient diet supplemented with ethionine in drinking water to induce hepatocarcinogenesis), CV groups with three different doses of CV (50, 150, and 300 mg/kg body weight), and CDE groups treated with different doses of CV (50, 150, and 300 mg/kg body weight). Rats were sacrificed at various weeks and liver tissues were embedded in paraffin blocks for immunohistochemistry studies. CV, at increasing doses, decreased the expression of anti-apoptotic protein, Bcl-2, but increased the expression of pro-apoptotic protein, caspase 8, in CDE rats, which was correlated with decreased hepatoctyes proliferation and increased apoptosis as determined by bromodeoxy-uridine (BrdU) labeling and terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) assay, respectively. Our study shows that CV has definite chemopreventive effect by inducing apoptosis via decreasing the expression of Bcl-2 and increasing the expression of caspase 8 in hepatocarcinogenesis-induced rats. PMID:19198018

O-GlcNAcylation regulates ischemia-induced neuronal apoptosis through AKT signaling

OpenAIRE

Shi, Jianhua; Gu, Jin-hua; Dai, Chun-ling; Gu, Jianlan; Jin, Xiaoxia; Sun, Jianming; Iqbal, Khalid; Liu, Fei; Gong, Cheng-Xin

2015-01-01

Apoptosis plays an important role in neural development and neurological disorders. In this study, we found that O-GlcNAcylation, a unique protein posttranslational modification with O-linked β-N-acetylglucosamine (GlcNAc), promoted apoptosis through attenuating phosphorylation/activation of AKT and Bad. By using co-immunoprecipitation and mutagenesis techniques, we identified O-GlcNAc modification at both Thr308 and Ser473 of AKT. O-GlcNAcylation-induced apoptosis was attenuated by over-expr...

Plk1 inhibition causes post-mitotic DNA damage and senescence in a range of human tumor cell lines.

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Denise L Driscoll

Full Text Available Plk1 is a checkpoint protein whose role spans all of mitosis and includes DNA repair, and is highly conserved in eukaryotes from yeast to man. Consistent with this wide array of functions for Plk1, the cellular consequences of Plk1 disruption are diverse, spanning delays in mitotic entry, mitotic spindle abnormalities, and transient mitotic arrest leading to mitotic slippage and failures in cytokinesis. In this work, we present the in vitro and in vivo consequences of Plk1 inhibition in cancer cells using potent, selective small-molecule Plk1 inhibitors and Plk1 genetic knock-down approaches. We demonstrate for the first time that cellular senescence is the predominant outcome of Plk1 inhibition in some cancer cell lines, whereas in other cancer cell lines the dominant outcome appears to be apoptosis, as has been reported in the literature. We also demonstrate strong induction of DNA double-strand breaks in all six lines examined (as assayed by γH2AX, which occurs either during mitotic arrest or mitotic-exit, and may be linked to the downstream induction of senescence. Taken together, our findings expand the view of Plk1 inhibition, demonstrating the occurrence of a non-apoptotic outcome in some settings. Our findings are also consistent with the possibility that mitotic arrest observed as a result of Plk1 inhibition is at least partially due to the presence of unrepaired double-strand breaks in mitosis. These novel findings may lead to alternative strategies for the development of novel therapeutic agents targeting Plk1, in the selection of biomarkers, patient populations, combination partners and dosing regimens.

Influence of radiation-induced apoptosis on development brain in molecular regulation

International Nuclear Information System (INIS)

Gu Guixiong

2000-01-01

An outline of current status on the influence of radiation on the development brain was given. Some genes as immediate early gene, Bcl-2 family, p53, heat shock protein and AT gene play an important regulation role in ionizing radiation-induced development brain cells apoptosis. And such biological factor as nerve growth factor, interleukin-1, tumor necrosis factor, basic fibroblast growth factor, transforming growth factor and so on have a vital protection function against ionizing radiation-induced cells apoptosis

A Subpopulation of the K562 Cells Are Killed by Curcumin Treatment after G2/M Arrest and Mitotic Catastrophe.

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Macario Martinez-Castillo

Full Text Available Curcumin is extensively investigated as a good chemo-preventive agent in the development of many cancers and particularly in leukemia, including treatment of chronic myelogenous leukemia and it has been proposed as an adjuvant for leukemia therapies. Human chronic myeloid leukemia cells (K562, were treated with 20 μM of curcumin, and we found that a subpopulation of these cells were arrested and accumulate in the G2/M phase of the cell cycle. Characterization of this cell subpopulation showed that the arrested cells presented nuclear morphology changes resembling those described for mitotic catastrophe. Mitotic cells displayed abnormal chromatin organization, collapse of the mitotic spindle and abnormal chromosome segregation. Then, these cells died in an apoptosis dependent manner and showed diminution in the protein levels of BCL-2 and XIAP. Moreover, our results shown that a transient activation of the nuclear factor κB (NFκB occurred early in these cells, but decreased after 6 h of the treatment, explaining in part the diminution of the anti-apoptotic proteins. Additionally, P73 was translocated to the cell nuclei, because the expression of the C/EBPα, a cognate repressor of the P73 gene, was decreased, suggesting that apoptosis is trigger by elevation of P73 protein levels acting in concert with the diminution of the two anti-apoptotic molecules. In summary, curcumin treatment might produce a P73-dependent apoptotic cell death in chronic myelogenous leukemia cells (K562, which was triggered by mitotic catastrophe, due to sustained BAX and survivin expression and impairment of the anti-apoptotic proteins BCL-2 and XIAP.

Recombinant Vaccinia Viruses Coding Transgenes of Apoptosis-Inducing Proteins Enhance Apoptosis But Not Immunogenicity of Infected Tumor Cells

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Tkachenko, Anastasiya; Richter, Vladimir

2017-01-01

Genetic modifications of the oncolytic vaccinia virus (VV) improve selective tumor cell infection and death, as well as activation of antitumor immunity. We have engineered a double recombinant VV, coding human GM-CSF, and apoptosis-inducing protein apoptin (VV-GMCSF-Apo) for comparing with the earlier constructed double recombinant VV-GMCSF-Lact, coding another apoptosis-inducing protein, lactaptin, which activated different cell death pathways than apoptin. We showed that both these recombinant VVs more considerably activated a set of critical apoptosis markers in infected cells than the recombinant VV coding GM-CSF alone (VV-GMCSF-dGF): these were phosphatidylserine externalization, caspase-3 and caspase-7 activation, DNA fragmentation, and upregulation of proapoptotic protein BAX. However, only VV-GMCSF-Lact efficiently decreased the mitochondrial membrane potential of infected cancer cells. Investigating immunogenic cell death markers in cancer cells infected with recombinant VVs, we demonstrated that all tested recombinant VVs were efficient in calreticulin and HSP70 externalization, decrease of cellular HMGB1, and ATP secretion. The comparison of antitumor activity against advanced MDA-MB-231 tumor revealed that both recombinants VV-GMCSF-Lact and VV-GMCSF-Apo efficiently delay tumor growth. Our results demonstrate that the composition of GM-CSF and apoptosis-inducing proteins in the VV genome is very efficient tool for specific killing of cancer cells and for activation of antitumor immunity. PMID:28951871

Paclitaxel Induces Apoptosis in Breast Cancer Cells through Different Calcium—Regulating Mechanisms Depending on External Calcium Conditions

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Pan, Zhi; Avila, Andrew; Gollahon, Lauren

2014-01-01

Previously, we reported that endoplasmic reticulum calcium stores were a direct target for paclitaxel initiation of apoptosis. Furthermore, the actions of paclitaxel attenuated Bcl-2 resistance to apoptosis through endoplasmic reticulum-mediated calcium release. To better understand the calcium-regulated mechanisms of paclitaxel-induced apoptosis in breast cancer cells, we investigated the role of extracellular calcium, specifically; whether influx of extracellular calcium contributed to and/or was necessary for paclitaxel-induced apoptosis. Our results demonstrated that paclitaxel induced extracellular calcium influx. This mobilization of extracellular calcium contributed to subsequent cytosolic calcium elevation differently, depending on dosage. Under normal extracellular calcium conditions, high dose paclitaxel induced apoptosis-promoting calcium influx, which did not occur in calcium-free conditions. In the absence of extracellular calcium an “Enhanced Calcium Efflux” mechanism in which high dose paclitaxel stimulated calcium efflux immediately, leading to dramatic cytosolic calcium decrease, was observed. In the absence of extracellular calcium, high dose paclitaxel’s stimulatory effects on capacitative calcium entry and apoptosis could not be completely restored. Thus, normal extracellular calcium concentrations are critical for high dose paclitaxel-induced apoptosis. In contrast, low dose paclitaxel mirrored controls, indicating that it occurs independent of extracellular calcium. Thus, extracellular calcium conditions only affect efficacy of high dose paclitaxel-induced apoptosis. PMID:24549172

The protective effect of resveratrol on human lens epithelial cells against ultraviolet-induced apoptosis

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Xue - Fang Chen

2013-06-01

Full Text Available AIM: To investigate the protective effect of resveratrol on human lens epithelial cells against ultraviolet-induced apoptosis. METHODS:Subcultured human lens epithelial cell line, ultraviolet induced cell apoptosis, 20μmol/L resveratrol pretreated cell, the indicators change was observed: rate of apoptosis was detected by flow cytometry and apoptosis-related factors of caspses-3 and caspase-9 were detected by colorimetric detection, ultrastructure changes were observed under transmission electron microscope. RESULTS: Flow cytometry instrument testing found that resveratrol can suppress the apoptosis induced by ultraviolet irradiation, caspses-3 and caspase-9 content in positive control group were significantly higher than that of the negative control group at the same time period, the difference was statistically significant(P<0.05; caspses-3 and caspase-9 content in experimental group were lower than that in the positive control group at the same time, the difference was statistically significant(P<0.05. In addition, the damage of human lens epithelial cells was alleviated with the incubation time of resveratrol elongated. CONCLUSION:Resveratrol may inhibit ultraviolet-induced apoptosis of human lens epithelial cells, it has preventive function against radioactive cataract, and it can provide reliable evidence for pursuing effective medicine to prevent and treat cataract.

Correlation of the microculture-kinetic drug-induced apoptosis assay with patient outcomes in initial treatment of adult acute myelocytic leukemia.

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Strickland, Stephen A; Raptis, Anastasios; Hallquist, Allan; Rutledge, James; Chernick, Michael; Perree, Mathieu; Talbott, Mahsa S; Presant, Cary A

2013-03-01

Overall survival (OS) with acute myeloid leukemia (AML) remains poor. Determining prognostic factors will help in selecting patients for appropriate treatments. Our aim was to determine whether the level of drug-induced apoptosis (chemosensitivity) demonstrated by the microculture-kinetic drug-induced apoptosis (MiCK) assay significantly predicted outcomes after standard AML induction therapy. A total of 109 patients with untreated AML had blood and/or bone marrow aspirate samples analyzed for anthracycline-induced apoptosis using the MiCK assay. The amount of apoptosis observed over 48 h was determined and expressed as kinetic units of apoptosis (KU). Complete remission (CR) was significantly higher (72%) in patients with high idarubicin-induced apoptosis >3 KU compared to patients with apoptosis ≤ 3 KU (p = 0.01). Multivariate analysis showed the only significant variables to be idarubicin-induced apoptosis and karyotype. Median overall survival of patients with idarubicin-induced apoptosis >3 KU was 16.1 months compared to 4.5 months in patients with apoptosis ≤ 3 KU (p = 0.004). Multivariate analysis showed the only significant variable to be idarubicin-induced apoptosis. Chemotherapy-induced apoptosis measured by the MiCK assay demonstrated significant correlation with outcomes and appears predictive of complete remission and overall survival for patients receiving standard induction chemotherapy.

Azadirachtin-induced apoptosis involves lysosomal membrane permeabilization and cathepsin L release in Spodoptera frugiperda Sf9 cells.

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Wang, Zheng; Cheng, Xingan; Meng, Qianqian; Wang, Peidan; Shu, Benshui; Hu, Qiongbo; Hu, Meiying; Zhong, Guohua

2015-07-01

Azadirachtin as a kind of botanical insecticide has been widely used in pest control. We previously reported that azadirachtin could induce apoptosis of Spodoptera litura cultured cell line Sl-1, which involves in the up-regulation of P53 protein. However, the detailed mechanism of azadirachtin-induced apoptosis is not clearly understood in insect cultured cells. The aim of the present study was to address the involvement of lysosome and lysosomal protease in azadirachtin-induced apoptosis in Sf9 cells. The result confirmed that azadirachtin indeed inhibited proliferation and induced apoptosis. The lysosomes were divided into different types as time-dependent manner, which suggested that changes of lysosomes were necessarily physiological processes in azadirachtin-induced apoptosis in Sf9 cells. Interestingly, we noticed that azadirachtin could trigger lysosomal membrane permeabilization and cathepsin L releasing to cytosol. Z-FF-FMK (a cathepsin L inhibitor), but not CA-074me (a cathepsin B inhibitor), could effectively hinder the apoptosis induced by azadirachtin in Sf9 cells. Meanwhile, the activity of caspase-3 could also be inactivated by the inhibition of cathepsin L enzymatic activity induced by Z-FF-FMK. Taken together, our findings suggest that azadirachtin could induce apoptosis in Sf9 cells in a lysosomal pathway, and cathepsin L plays a pro-apoptosis role in this process through releasing to cytosol and activating caspase-3. Copyright © 2015 Elsevier Ltd. All rights reserved.

Saccharomyces cerevisiae mutants with enhanced induced mutation and altered mitotic gene conversion.

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Ivanov, E L; Kovaltzova, S V; Korolev, V G

1989-08-01

We have developed a method to isolate yeast (Saccharomyces cerevisiae) mutants with enhanced induced mutagenesis based on nitrous acid-induced reversion of the ade2-42 allele. Six mutants have been isolated and designated him (high induced mutagenesis), and 4 of them were studied in more detail. The him mutants displayed enhanced reversion of the ade2-42 allele, either spontaneous or induced by nitrous acid, UV light, and the base analog 6-N-hydroxylaminopurine, but not by gamma-irradiation. It is worth noting that the him mutants turned out not to be sensitive to the lethal effects of the mutagens used. The enhancement in mutation induced by nitrous acid, UV light, and 6-N-hydroxylaminopurine has been confirmed in a forward-mutation assay (induction of mutations in the ADE1, ADE2 genes). The latter agent revealed the most apparent differences between the him mutants and the wild-type strain and was, therefore, chosen for the genetic analysis of mutants, him mutations analyzed behaved as a single Mendelian trait; complementation tests indicated 3 complementation groups (HIM1, HIM2, and HIM3), each containing 1 mutant allele. Uracil-DNA glycosylase activity was determined in crude cell extracts, and no significant differences between the wild-type and him strains were detected. Spontaneous mitotic gene conversion at the ADE2 locus is altered in him1 strains, either increased or decreased, depending on the particular heteroallelic combination. Genetic evidence strongly suggests him mutations to be involved in a process of mismatch correction of molecular heteroduplexes.

Advanced oxidation protein products induce chondrocyte apoptosis via receptor for advanced glycation end products-mediated, redox-dependent intrinsic apoptosis pathway.

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Wu, Qian; Zhong, Zhao-Ming; Zhu, Si-Yuan; Liao, Cong-Rui; Pan, Ying; Zeng, Ji-Huan; Zheng, Shuai; Ding, Ruo-Ting; Lin, Qing-Song; Ye, Qing; Ye, Wen-Bin; Li, Wei; Chen, Jian-Ting

2016-01-01

Pro-inflammatory cytokine-induced chondrocyte apoptosis is a primary cause of cartilage destruction in the progression of rheumatoid arthritis (RA). Advanced oxidation protein products (AOPPs), a novel pro-inflammatory mediator, have been confirmed to accumulate in patients with RA. However, the effect of AOPPs accumulation on chondrocyte apoptosis and the associated cellular mechanisms remains unclear. The present study demonstrated that the plasma formation of AOPPs was enhanced in RA rats compared with normal. Then, chondrocyte were treated with AOPPs-modified rat serum albumin (AOPPs-RSA) in vitro. Exposure of chondrocyte to AOPPs activated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and increased expression of NADPH oxidase subunits, which was mediated by receptor for advanced glycation end products (RAGE), but not scavenger receptor CD36. Moreover, AOPPs challenge triggered NADPH oxidase-dependent ROS generation which induced mitochondrial dysfunction and endoplasmic reticulum stress resulted in activation of caspase family that eventually lead to apoptosis. Lastly, blockade of RAGE, instead of CD36, largely attenuated these signals. Our study demonstrated first time that AOPPs induce chondrocyte apoptosis via RAGE-mediated and redox-dependent intrinsic apoptosis pathway in vitro. These data implicates that AOPPs may represent a novel pathogenic factor that contributes to RA progression. Targeting AOPPs-triggered cellular mechanisms might emerge as a promising therapeutic option for patients with RA.

Caffeic Acid Induces Apoptosis in Human Cervical Cancer Cells Through the Mitochondrial Pathway

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Wei-Chun Chang

2010-12-01

Conclusion: Caffeic acid induces apoptosis by inhibiting Bcl-2 activity, leading to release of cytochrome c and subsequent activation of caspase-3, indicating that caffeic acid induces apoptosis via the mitochondrial apoptotic pathway. This also suggests that caffeic acid has a strong anti-tumor effect and may be a promising chemopreventive or chemotherapeutic agent.

Globular Adiponectin Attenuated H2O2-Induced Apoptosis in Rat Chondrocytes by Inducing Autophagy Through the AMPK/ mTOR Pathway.

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Hu, Junzheng; Cui, Weiding; Ding, Wenxiao; Gu, Yanqing; Wang, Zhen; Fan, Weimin

2017-01-01

Chondrocyte apoptosis is closely related to the development and progression of osteoarthritis. Global adiponectin (gAPN), secreted from adipose tissue, possesses potent anti-inflammatory and antiapoptotic properties in various cell types. This study aimed to investigate the role of autophagy induced by gAPN in the suppression of H2O2-induced apoptosis and the potential mechanism of gAPN-induced autophagy in chondrocytes. H2O2 was used to induce apoptotic injury in rat chondrocytes. CCK-8 assay was performed to determine the viability of cells treated with different concentrations of gAPN with or without H2O2. Cell apoptosis was detected by flow cytometry and TUNEL staining. Mitochondrial membrane potential was examined using JC-1 fluorescence staining assay. The autophagy inhibitors 3-MA and Bafilomycin A1 were used to treat cells and then evaluate the effect of gAPN-induced autophagy. To determine the downstream pathway, chondrocytes were preincubated with the AMPK inhibitor Compound C. Beclin-1, LC3B, P62 and apoptosis-related proteins were identified by Western blot analysis. H2O2 (400 µM)-induced chondrocytes apoptosis and caspase-3 activation were attenuated by gAPN (0.5 µg/mL). gAPN increased Bcl-2 expression and decreased Bax expression. The loss of mitochondrial membrane potential induced by H2O2 was also abolished by gAPN. Furthermore, the antiapoptotic effect of gAPN was related to gAPN-induced autophagy by increased formation of Beclin-1 and LC3B and P62 degradation. In particular, the inhibition of gAPN-induced autophagy by 3-MA prevented the protective effect of gAPN on apoptosis induced by H2O2. Moreover, gAPN increased p-AMPK expression and decreased p-mTOR expression. Compound C partly suppressed the expression of autophagy-related proteins and restored the expression of p-mTOR suppressed by gAPN. Thus, the AMPK/mTOR pathway played an important role in the induction of autophagy and protection of H2O2-induced chondrocytes apoptosis by gAPN. g

Globular Adiponectin Attenuated H2O2-Induced Apoptosis in Rat Chondrocytes by Inducing Autophagy Through the AMPK/ mTOR Pathway

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Junzheng Hu

2017-08-01

Full Text Available Background/Aims: Chondrocyte apoptosis is closely related to the development and progression of osteoarthritis. Global adiponectin (gAPN, secreted from adipose tissue, possesses potent anti-inflammatory and antiapoptotic properties in various cell types. This study aimed to investigate the role of autophagy induced by gAPN in the suppression of H2O2-induced apoptosis and the potential mechanism of gAPN-induced autophagy in chondrocytes. Methods: H2O2 was used to induce apoptotic injury in rat chondrocytes. CCK-8 assay was performed to determine the viability of cells treated with different concentrations of gAPN with or without H2O2. Cell apoptosis was detected by flow cytometry and TUNEL staining. Mitochondrial membrane potential was examined using JC-1 fluorescence staining assay. The autophagy inhibitors 3-MA and Bafilomycin A1 were used to treat cells and then evaluate the effect of gAPN-induced autophagy. To determine the downstream pathway, chondrocytes were preincubated with the AMPK inhibitor Compound C. Beclin-1, LC3B, P62 and apoptosis-related proteins were identified by Western blot analysis. Results: H2O2 (400 µM-induced chondrocytes apoptosis and caspase-3 activation were attenuated by gAPN (0.5 µg/mL. gAPN increased Bcl-2 expression and decreased Bax expression. The loss of mitochondrial membrane potential induced by H2O2 was also abolished by gAPN. Furthermore, the antiapoptotic effect of gAPN was related to gAPN-induced autophagy by increased formation of Beclin-1 and LC3B and P62 degradation. In particular, the inhibition of gAPN-induced autophagy by 3-MA prevented the protective effect of gAPN on apoptosis induced by H2O2. Moreover, gAPN increased p-AMPK expression and decreased p-mTOR expression. Compound C partly suppressed the expression of autophagy-related proteins and restored the expression of p-mTOR suppressed by gAPN. Thus, the AMPK/mTOR pathway played an important role in the induction of autophagy and protection of

Involvement of caspase-dependent and -independent apoptotic pathways in cisplatin-induced apoptosis

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Liu, Lei; Zhang, Yingjie; Wang, Xianwang

2009-02-01

Cisplatin, an efficient anticancer agent, can trigger multiple apoptotic pathways in cancer cells. However, the signal transduction pathways in response to cisplatin-based chemotherapy are complicated, and the mechanism is not fully understood. In current study, we showed that, during cisplatin-induced apoptosis of human lung adenocarcinoma cells, both the caspase-dependent and -independent pathways were activated. Herein, we reported that after cisplatin treatment, the activities of caspase-9/-3 were sharply increased; pre-treatment with Z-LEHD-fmk (inhibitor of caspase-9), Z-DEVD-fmk (inhibitor of caspase-3), and Z-VAD-fmk (a pan-caspase inhibitor) increased cell viability and decreased apoptosis, suggesting that caspase-mediated apoptotic pathway was activated following cisplatin treatment. Confocal imaging of the cells transfected with AIF-GFP demonstrated that AIF release occurred about 9 h after cisplatin treatment. The event proceeded progressively over time, coinciding with a nuclear translocation and lasting for more than 2 hours. Down-regulation of AIF by siRNA also significantly increased cell viability and decreased apoptosis, these results suggested that AIF-mediated caspase-independent apoptotic pathway was involved in cispatin-induced apoptosis. In conclusion, the current study demonstrated that both caspase-dependent and -independent apoptotic pathways were involved in cisplatin-induced apoptosis in human lung adenocarcinoma cells.

Arsenic induces cell apoptosis in cultured osteoblasts through endoplasmic reticulum stress

International Nuclear Information System (INIS)

Tang, C.-H.; Chiu, Y.-C.; Huang, C.-F.; Chen, Y.-W.; Chen, P.-C.

2009-01-01

Osteoporosis is characterized by low bone mass resulting from an imbalance between bone resorption by osteoclasts and bone formation by osteoblasts. Therefore, decreased bone formation by osteoblasts may lead to the development of osteoporosis, and rate of apoptosis is responsible for the regulation of bone formation. Arsenic (As) exists ubiquitously in our environment and increases the risk of neurotoxicity, liver injury, peripheral vascular disease and cancer. However, the effect of As on apoptosis of osteoblasts is mostly unknown. Here, we found that As induced cell apoptosis in osteoblastic cell lines (including hFOB, MC3T3-E1 and MG-63) and mouse bone marrow stromal cells (M2-10B4). As also induced upregulation of Bax and Bak, downregulation of Bcl-2 and dysfunction of mitochondria in osteoblasts. As also triggered endoplasmic reticulum (ER) stress, as indicated by changes in cytosolic-calcium levels. We found that As increased the expression and activities of glucose-regulated protein 78 (GRP78) and calpain. Transfection of cells with GRP78 or calpain siRNA reduced As-mediated cell apoptosis in osteoblasts. Therefore, our results suggest that As increased cell apoptosis in cultured osteoblasts and increased the risk of osteoporosis.

Biological dosimetry: the potential use of radiation-induced apoptosis in human T-lymphocytes

International Nuclear Information System (INIS)

Menz, R.; Andres, R.; Larsson, B.; Ozsahin, M.; Crompton, N.E.A.; Trott, K.

1997-01-01

An assay for biological dosimetry based on the induction of apoptosis in human T-lymphocytes is described. Radiation-induced apoptosis was assessed by flow cytometric identification of cells displaying apoptosis-associated DNA condensation. CD4 and CD8 T-lymphocytes were analysed. They were recognized on the basis of their cell-surface antigens. Four parameters were measured for both cell types: cell size, granularity, antigen immunofluorescence and DNA content. Apoptosis was quantified as the fraction of CD4-, or CD8-positive cells with a characteristic reduction of cell size and DNA content. At doses below 1 Gy, levels of radiation-induced apoptosis increased for up to 5 days after irradiation. Optimal dose discrimination was observed 4 days after irradiation, at which time the dose-response curves were linear, with a slope of 8% ± 0.5% per 0.1 Gy. In controlled, dose-response experiments the lowest dose level at which the radiation-induced apoptosis frequency was still significantly above control was 0.05 Gy. After 5 days post-irradiation incubation, intra- and interdonor variations were measured and found to be similar; thus, apoptotic levels depend more on the dose than on the donor. The results demonstrate the potential of this assay as a biological dosimeter. (orig.)

SET mediates TCE-induced liver cell apoptosis through dephosphorylation and upregulation of nucleolin.

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Ren, Xiaohu; Huang, Xinfeng; Yang, Xifei; Liu, Yungang; Liu, Wei; Huang, Haiyan; Wu, Desheng; Zou, Fei; Liu, Jianjun

2017-06-20

Trichloroethylene (TCE) is an occupational and environmental chemical that can cause severe hepatotoxicity. While our previous studies showed that the phosphatase inhibitor SET is a key mediator of TCE-induced liver cell apoptosis, the molecular mechanisms remain elusive. Using quantitative phosphoproteomic analysis, we report here that nucleolin is a SET-regulated phosphoprotein in human liver HL-7702 cells. Functional analysis suggested that SET promoted dephosphorylation of nucleolin, decreased its binding to its transcriptional activator, c-myc, and upregulated nucleolin expression in TCE-treated cells. Importantly, TCE-induced hepatocyte apoptosis was significantly attenuated when nucleolin was downregulated with specific siRNAs. These findings indicate that TCE may induce hepatocyte apoptosis via SET-mediated dephosphorylation and overexpression of nucleolin.

Hot water extract of Chlorella vulgaris induced DNA damage and apoptosis

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Yusof, Yasmin Anum Mohd; Md. Saad, Suhana; Makpol, Suzana; Shamaan, Nor Aripin; Ngah, Wan Zurinah Wan

2010-01-01

OBJECTIVES: The aim of this study was to determine the antiproliferative and apoptotic effects of hot water extracts of Chlorella vulgaris on hepatoma cell line HepG2. INTRODUCTION: The search for food and spices that can induce apoptosis in cancer cells has been a major study interest in the last decade. Chlorella vulgaris, a unicellular green algae, has been reported to have antioxidant and anti‐cancer properties. However, its chemopreventive effects in inhibiting the growth of cancer cells have not been studied in great detail. METHODS: HepG2 liver cancer cells and WRL68 normal liver cells were treated with various concentrations (0‐4 mg/ml) of hot water extract of C. vulgaris after 24 hours incubation. Apoptosis rate was evaluated by TUNEL assay while DNA damage was assessed by Comet assay. Apoptosis proteins were evaluated by Western blot analysis. RESULTS: Chlorella vulgaris decreased the number of viable HepG2 cells in a dose dependent manner (p Chlorella vulgaris tested. Evaluation of apoptosis by TUNEL assay showed that Chlorella vulgaris induced a higher apoptotic rate (70%) in HepG2 cells compared to normal liver cells, WRL68 (15%). Western blot analysis showed increased expression of pro‐ apoptotic proteins P53, Bax and caspase‐3 in the HepG2 cells compared to normal liver cells WRL68, and decreased expression of the anti‐apoptotic protein Bcl‐2. CONCLUSIONS: Chlorella vulgaris may have anti‐cancer effects by inducing apoptosis signaling cascades via an increased expression of P53, Bax and caspase‐3 proteins and through a reduction of Bcl‐2 protein, which subsequently lead to increased DNA damage and apoptosis. PMID:21340229

Inhibitory Effect of Lycopene on Amyloid-β-Induced Apoptosis in Neuronal Cells.

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Hwang, Sinwoo; Lim, Joo Weon; Kim, Hyeyoung

2017-08-16

Alzheimer's disease (AD) is a fatal neurodegenerative disease. Brain amyloid-β deposition is a crucial feature of AD, causing neuronal cell death by inducing oxidative damage. Reactive oxygen species (ROS) activate NF-κB, which induces expression of Nucling. Nucling is a pro-apoptotic factor recruiting the apoptosome complex. Lycopene is an antioxidant protecting from oxidative stress-induced cell damage. We investigated whether lycopene inhibits amyloid-β-stimulated apoptosis through reducing ROS and inhibiting mitochondrial dysfunction and NF-κB-mediated Nucling expression in neuronal SH-SY5Y cells. We prepared cells transfected with siRNA for Nucling or nontargeting control siRNA to determine the role of Nucling in amyloid-β-induced apoptosis. The amyloid-β increased intracellular and mitochondrial ROS levels, apoptotic indices (p53, Bax/Bcl-2 ratio, caspase-3 cleavage), NF-kB activation and Nucling expression, while cell viability, mitochondrial membrane potential, and oxygen consumption rate decreased in SH-SY5Y cells. Lycopene inhibited these amyloid-β-induced alterations. However, amyloid-β did not induce apoptosis, determined by cell viability and apoptotic indices (p53, Bax/Bcl-2 ratio, caspase-3 cleavage), in the cells transfected with siRNA for Nucling. Lycopene inhibited apoptosis by reducing ROS, and by inhibiting mitochondrial dysfunction and NF-κB-target gene Nucling expression in neuronal cells. Lycopene may be beneficial for preventing oxidative stress-mediated neuronal death in patients with neurodegeneration.

Influence of novobiocin on mitotic events and radiation-induced G2-arrest

International Nuclear Information System (INIS)

Rowley, R.

1987-01-01

Novobiocin was used in CHO cells to test for an involvement of topoisomerase II activity in; 1) the induction of, and recovery from, radiation-induced G 2 -arrest and 2) progression through mitosis. Novobiocin blocked recovery from G 2 -arrest with a concentration dependency which suggested that this effect resulted from protein synthesis inhibition. Novobiocin alone, at concentrations above 500 μgml, blocked cell progression in early mitosis. The transition point was distinct from that of protein and RNA synthesis inhibitors and was the only arrest point in mitosis. A similar block was imposed by coumermycin. While this may indicate a requirement for topoisomerase II activity during chromosome condensation, it was also associated with inhibition of histone phosphorylation. Histone H3 phosphorylation is believed to be necessary for chromosome condensation and, when inhibited by novobiocin, correlates with a block in premature chromatin condensation in tsBN2 cells. The authors' data thus unite these two findings, provide an opportunity to analyse the temporal relationship between histone phosphorylation and mitotic events and suggest that topological reorganization of the chromatin is not involved in radiation-induced G 2 arrest

Valsartan Protects Against Contrast-Induced Acute Kidney Injury in Rats by Inhibiting Endoplasmic Reticulum Stress-Induced Apoptosis.

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Sun, Yan; Peng, Ping-An; Ma, Yue; Liu, Xiao-Li; Yu, Yi; Jia, Shuo; Xu, Xiao-Han; Wu, Si-Jing; Zhou, Yu-Jie

2017-01-01

Contrast-induced acute kidney injury (CI-AKI) is a serious complication of the administration of iodinated contrast media (CM) for diagnostic and interventional cardiovascular procedures and is associated with substantial morbidity and mortality. While the preventative measures can mitigate the risk of CI-AKI, there remains a need for novel and effective therapeutic approaches. The pathogenesis of CI-AKI is complex and not completely understood. CM-induced renal tubular cell apoptosis caused by the activation of endoplasmic reticulum (ER) stress is involved in CIAKI. We previously demonstrated that valsartan alleviated CM-induced human renal tubular cell apoptosis by inhibiting ER stress in vitro. However, the nephroprotective effect of valsartan on CI-AKI in vivo has not been investigated. Therefore, the aim of this study was to explore the protective effect of valsartan in a rat model of CI-AKI by measuring the amelioration of renal damage and the changes in ER stressrelated biomarkers. Our results showed that the radiocontrast agent meglumine diatrizoate caused significant renal insufficiency, renin-angiotensin system (RAS) activation, and renal tubular apoptosis by triggering ER stress through activation of glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), caspase 12, CCAAT/enhancer-binding protein-homologous protein (CHOP) and c-Jun N-terminal protein kinase (JNK) (Pvalsartan significantly alleviated renal dysfunction, pathological injury, and apoptosis along with the inhibition of ER stressrelated biomarkers (PValsartan could protect against meglumine diatrizoate-induced kidney injury in rats by inhibiting the ER stress-induced apoptosis, making it a promising strategy for preventing CI-AKI. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Down-regulation of HSP27 sensitizes TRAIL-resistant tumor cell to TRAIL-induced apoptosis

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Zhuang, Hongqin; Jiang, Weiwei; Cheng, Wei

2010-01-01

Tumor necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL) has recently emerged as a cancer therapeutic agent because it preferentially induces apoptosis in human cancer over normal cells. Most tumor cells, including lung cancer cell line A549, unfortunately, are resistant to TRAIL tre...

Caspase-Independent Apoptosis Induced by Reperfusion Following Ischemia without Bile Duct Occlusion in Rat Liver.

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Matsui, Nobuaki; Yoshioka, Rie; Nozawa, Asako; Kobayashi, Naonobu; Shichijo, Yukari; Yoshikawa, Tadatoshi; Akagi, Masaaki

2017-01-01

The contribution of caspases to hepatic ischemia/reperfusion (I/R)-induced apoptosis has not been completely understood yet. Several studies have demonstrated increased caspase activity during I/R and the protective effect of caspase inhibitors against I/R injuries. However, reports with opposing results also exist. Herein, we examined the contribution of caspases to the I/R-induced hepatic apoptosis in rats using caspase inhibitors and specific substrates of caspases. Hepatic I/R was induced via a 2-h occlusion of the portal vein and the hepatic artery, without conducting bile duct occlusion. DNA laddering and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end-labeling (TUNEL)-positive cells were increased at 3 h after reperfusion. Pretreatment with caspase inhibitors (Z-Asp-2,6-dichlorobenzoyloxymethylketone (Z-Asp-cmk) 2 or 10 mg/kg intravenously (i.v.), 20 mg/kg intraperitoneally (i.p.), Z-Val-Ala-Asp(OMe)-fluoromethylketone (Z-VAD-fmk) 3 mg/kg i.v.) failed to reduce apoptosis induced by I/R. Interestingly, apoptosis induced by the portal triad (hepatic artery, portal vein, and bile duct) occlusion/reperfusion could be marginally attenuated using Z-Asp-cmk (2 mg/kg i.v.). The cleavage activity for Ac-DEVD-α-(4-methylcoumaryl-7-amide) (MCA), a caspase-3/7/8/9 substrate, was significantly increased by I/R. Conversely, the cleavage activities for Ac-DNLD-MCA and MCA-VDQVDGW[K-DNP]-NH 2 , specific substrates for caspase-3 and -7 respectively, were decreased by I/R. Protein expression of the cellular inhibitor of apoptosis protein 2 (c-IAP2), an endogenous caspase inhibitor, was increased by ischemia. Nuclear translocation of the apoptosis-inducing factor (AIF), an initiator protein of caspase-independent apoptosis, was also increased during I/R. These results suggest that caspases are inhibited by c-IAP2 induced during ischemia and that AIF may be involved in initiation of apoptosis induced by hepatic I/R without

Curcumin induces apoptosis and protective autophagy in castration-resistant prostate cancer cells through iron chelation

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Yang C

2017-02-01

Full Text Available Chunguang Yang,1,* Xueyou Ma,1,* Zhihua Wang,1 Xing Zeng,1 Zhiquan Hu,1 Zhangqun Ye,1 Guanxin Shen2 1Department of Urology, Tongji Hospital, 2Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People’s Republic of China *These authors contributed equally to this work Background: Curcumin induces apoptosis and autophagy in different cancer cells. Moreover, chemical and biological experiments have evidenced that curcumin is a biologically active iron chelator and induces cytotoxicity through iron chelation. We thus hypothesized that curcumin may induce apoptosis and autophagy in castration-resistant prostate cancer (CRPC cells through its iron-chelating properties.Materials and methods: CRPC cells were loaded with curcumin alone or in combination with ferric ammonium citrate (FAC. Cytotoxicity was measured by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay. Apoptosis was assessed by flow cytometry, terminal deoxynucleotidyl transferase nick end labeling (TUNEL assay and caspase activity. Autophagy status was analyzed by the detection of autophagosomes and light chain 3-II (LC3-II using transmission electron microscopy and Western blot. Iron-binding activity of curcumin was assessed by spectrophotometry and MTT assay. The expression levels of transferrin receptor 1 (TfR1 and iron regulatory protein 1 (IRP1 were examined by Western blot.Results: Curcumin induced apoptosis and autophagy in CRPC cells. Combining curcumin with autophagy inhibitors (3-methyladenine [3-MA] synergized the apoptotic effect of curcumin. Moreover, curcumin bound to FAC at a ratio of ~1:1, as assessed by spectrophotometry and MTT assay. Apoptosis and autophagy induced by curcumin were counteracted by equal amounts of FAC. At apoptosis- and autophagy-inducing concentrations, curcumin enhanced the expression levels of TfR1 and IRP1, indicative of iron deprivation induced by curcumin

Calcium signals and caspase-12 participated in paraoxon-induced apoptosis in EL4 cells.

Science.gov (United States)

Li, Lan; Cao, Zhiheng; Jia, Pengfei; Wang, Ziren

2010-04-01

In order to investigate whether calcium signals participate in paraoxon (POX)-induced apoptosis in EL4 cells, real-time laser scanning confocal microscopy (LSCM) was used to detect Ca(2+) changes during the POX application. Apoptotic rates of EL4 cells and caspase-12 expression were also evaluated. POX (1-10nM) increased intracellular calcium concentration ([Ca(2+)]i) in EL4 cells in a dose-dependent manner at early stage (0-2h) of POX application, and apoptotic rates of EL4 cells after treatment with POX for 16h were also increased in a dose-dependent manner. Pre-treatment with EGTA, heparin or procaine attenuated POX-induced [Ca(2+)]i elevation and apoptosis. Additionally, POX up-regulated caspase-12 expression in a dose-dependent manner, and pre-treatment with EGTA, heparin or procaine significantly inhibited POX-induced increase of caspase-12 expression. Our results suggested that POX induced [Ca(2+)]i elevation in EL4 cells at the early stage of POX-induced apoptosis, which might involve Ca(2+) efflux from the endoplasmic reticulum (ER) and Ca(2+) influx from extracellular medium. Calcium signals and caspase-12 were important upstream messengers in POX-induced apoptosis in EL4 cells. The ER-associated pathway possibly operated in this apoptosis. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Blockade of store-operated calcium entry alleviates ethanol-induced hepatotoxicity via inhibiting apoptosis

Energy Technology Data Exchange (ETDEWEB)

Cui, Ruibing [Department of Hepatology and Gastroenterology, Qilu Hospital of Shandong University, Jinan, Shandong Province 250012 (China); Yan, Lihui [Shandong Normal University, Jinan, Shandong Province 250012 (China); Luo, Zheng; Guo, Xiaolan [Department of Hepatology and Gastroenterology, Qilu Hospital of Shandong University, Jinan, Shandong Province 250012 (China); Yan, Ming, E-mail: ymylh@163.com [Department of Hepatology and Gastroenterology, Qilu Hospital of Shandong University, Jinan, Shandong Province 250012 (China)

2015-08-15

Extracellular Ca{sup 2+} influx has been suggested to play a role in ethanol-induced hepatocyte apoptosis and necrosis. Previous studies indicated that store-operated Ca{sup 2+} entry (SOCE) was involved in liver injury induced by ethanol in HepG2 cells. However, the mechanisms underlying liver injury caused by SOCE remain unclear. We aimed to investigate the effects and mechanism of SOCE inhibition on liver injury induced by ethanol in BRL cells and Sprague–Dawley rats. Our data demonstrated that ethanol (0–400 mM) dose-dependently increased hepatocyte injury and 100 mM ethanol significantly upregulated the mRNA and protein expression of SOC for at least 72 h in BRL cells. Blockade of SOCE by pharmacological inhibitors and sh-RNA knockdown of STIM1 and Orai1 attenuated intracellular Ca{sup 2+} overload, restored the mitochondrial membrane potential (MMP), decreased cytochrome C release and inhibited ethanol-induced apoptosis. STIM1 and Orai1 expression was greater in ethanol-treated than control rats, and the SOCE inhibitor corosolic acid ameliorated the histopathological findings and alanine transaminase and aspartate transaminase activity as well as decreased cytochrome C release and inhibited alcohol-induced cell apoptosis. These findings suggest that SOCE blockade could alleviate alcohol-induced hepatotoxicity via inhibiting apoptosis. SOCE might be a useful therapeutic target in alcoholic liver diseases. - Highlights: • Blockade of SOCE alleviated overload of Ca{sup 2+} and hepatotoxicity after ethanol application. • Blockade of SOCE inhibited mitochondrial apoptosis after ethanol application. • SOCE might be a useful therapeutic target in alcoholic liver diseases.

Ghrelin ameliorates the human alveolar epithelial A549 cell apoptosis induced by lipopolysaccharide

International Nuclear Information System (INIS)

Huang, Chunrong; Zheng, Haichong; He, Wanmei; Lu, Guifang; Li, Xia; Deng, Yubin; Zeng, Mian

2016-01-01

Ghrelin is a gastric acyl-peptide that plays an inhibitory role in cell apoptosis. Herein we investigate the protective effects of ghrelin in LPS-induced apoptosis of human alveolar epithelial A549 cells, along with the possible molecular mechanisms. LPS exposure impaired cell viability and increased apoptosis of A549 cells significantly in concentration- and time-dependent manners embodied in increased Bax and cleaved caspase-3 production, coupled with decreased Bcl-2 levels. Simultaneously, LPS remarkably decreased the expression of phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) and extracellular signal-regulated kinas (ERK) in A549 cells. However, ghrelin'pretreatment ameliorated LPS-caused alterations in the ratio of Bax/Bcl-2 and cleaved caspase-3 expression, whereas activated the PI3K/Akt and ERK signaling. These results demonstrate that ghrelin lightens LPS-induced apoptosis of human alveolar epithelial cells partly through activating the PI3K/Akt and ERK pathway and thereby might benefit alleviating septic ALI. -- Graphical abstract: Ghrelin ameliorates the human alveolar epithelial A549 cells apoptosis induced by lipopolysaccharide partly through activating the PI3K/Akt and ERK pathway. Display Omitted -- Highlights: •It has been observed that LPS insult significantly increased apoptosis in A549 cells. •Both Akt and ERK signaling are critical adapter molecules to mediate the ghrelin-mediated proliferative effect. •Ghrelin may have a therapeutic effect in the prevention of LPS-induced apoptosis.

Ghrelin ameliorates the human alveolar epithelial A549 cell apoptosis induced by lipopolysaccharide

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Huang, Chunrong; Zheng, Haichong; He, Wanmei; Lu, Guifang; Li, Xia [Department of Medical Intensive Care Unit, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080 (China); Deng, Yubin, E-mail: dengyub@mail.sysu.edu.cn [Research Center of Translational Medicine, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080 (China); Zeng, Mian, E-mail: zengmian2004@163.com [Department of Medical Intensive Care Unit, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080 (China)

2016-05-20

Ghrelin is a gastric acyl-peptide that plays an inhibitory role in cell apoptosis. Herein we investigate the protective effects of ghrelin in LPS-induced apoptosis of human alveolar epithelial A549 cells, along with the possible molecular mechanisms. LPS exposure impaired cell viability and increased apoptosis of A549 cells significantly in concentration- and time-dependent manners embodied in increased Bax and cleaved caspase-3 production, coupled with decreased Bcl-2 levels. Simultaneously, LPS remarkably decreased the expression of phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) and extracellular signal-regulated kinas (ERK) in A549 cells. However, ghrelin'pretreatment ameliorated LPS-caused alterations in the ratio of Bax/Bcl-2 and cleaved caspase-3 expression, whereas activated the PI3K/Akt and ERK signaling. These results demonstrate that ghrelin lightens LPS-induced apoptosis of human alveolar epithelial cells partly through activating the PI3K/Akt and ERK pathway and thereby might benefit alleviating septic ALI. -- Graphical abstract: Ghrelin ameliorates the human alveolar epithelial A549 cells apoptosis induced by lipopolysaccharide partly through activating the PI3K/Akt and ERK pathway. Display Omitted -- Highlights: •It has been observed that LPS insult significantly increased apoptosis in A549 cells. •Both Akt and ERK signaling are critical adapter molecules to mediate the ghrelin-mediated proliferative effect. •Ghrelin may have a therapeutic effect in the prevention of LPS-induced apoptosis.

TIMP-1 gene deficiency increases tumour cell sensitivity to chemotherapy-induced apoptosis

DEFF Research Database (Denmark)

Davidsen, Marie Louise; Würts, S.Ø.; Rømer, Maria Unni Koefoed

2006-01-01

deficiency increases the response to chemotherapy considerably, confirming that TIMP-1 protects the cells from apoptosis. This is to our knowledge the first study investigating TIMP-1 and chemotherapy-induced apoptosis employing a powerful model system comprising TIMP-1 gene-deficient cells...... this hypothesis, we have established TIMP-1 gene-deficient and TIMP-1 wild-type fibrosarcoma cells from mouse lung tissue. We have characterised these cells with regard to TIMP-1 genotype, TIMP-1 expression, malignant transformation and sensitivity to chemotherapy-induced apoptosis. We show that TIMP-1 gene...... and their genetically identical wild-type controls. For future studies, this cell system can be used to uncover the mechanisms and signalling pathways involved in the TIMP-1-mediated inhibition of apoptosis as well as to investigate the possibility of using TIMP-1 inhibitors to optimise the effect of conventional...

A novel firefly luciferase biosensor enhances the detection of apoptosis induced by ESAT-6 family proteins of Mycobacterium tuberculosis

International Nuclear Information System (INIS)

Shi, Junwei; Zhang, Huan; Fang, Liurong; Xi, Yongqiang; Zhou, Yanrong; Luo, Rui; Wang, Dang; Xiao, Shaobo; Chen, Huanchun

2014-01-01

Highlights: • We developed a novel firefly luciferase based biosensor to detect apoptosis. • The novel biosensor 233-DnaE-DEVDG was reliable, sensitive and convenient. • 233-DnaE-DEVDG faithfully indicated ESAT-6 family proteins of Mycobacterium tuberculosis induced apoptosis. • EsxA, esxT and esxL in ESAT-6 family proteins induced apoptosis. • Activation of nuclear factor-κB (NF-κB) participated in esxT-induced apoptosis. - Abstract: The activation of caspase-3 is a key surrogate marker for detecting apoptosis. To quantitate caspase-3 activity, we constructed a biosensor comprising a recombinant firefly luciferase containing a caspase-3 cleavage site. When apoptosis was induced, caspase-3 cleavage of the biosensor activated firefly luciferase by a factor greater than 25. The assay conveniently detected apoptosis in real time, indicating that it will facilitate drug discovery. We screened ESAT-6 family proteins of Mycobacterium tuberculosis and found that esxA, esxT and esxL induced apoptosis. Further, activation of nuclear factor-κB (NF-κB) and the NF-κB-regulated genes encoding tumor necrosis factor-α (TNF-α) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) participated in esxT-induced apoptosis. We conclude that this assay is useful for high-throughput screening to identify and characterize proteins and drugs that regulate apoptosis

A novel firefly luciferase biosensor enhances the detection of apoptosis induced by ESAT-6 family proteins of Mycobacterium tuberculosis

Energy Technology Data Exchange (ETDEWEB)

Shi, Junwei; Zhang, Huan; Fang, Liurong; Xi, Yongqiang; Zhou, Yanrong; Luo, Rui; Wang, Dang, E-mail: wangdang511@126.com; Xiao, Shaobo; Chen, Huanchun

2014-10-03

Highlights: • We developed a novel firefly luciferase based biosensor to detect apoptosis. • The novel biosensor 233-DnaE-DEVDG was reliable, sensitive and convenient. • 233-DnaE-DEVDG faithfully indicated ESAT-6 family proteins of Mycobacterium tuberculosis induced apoptosis. • EsxA, esxT and esxL in ESAT-6 family proteins induced apoptosis. • Activation of nuclear factor-κB (NF-κB) participated in esxT-induced apoptosis. - Abstract: The activation of caspase-3 is a key surrogate marker for detecting apoptosis. To quantitate caspase-3 activity, we constructed a biosensor comprising a recombinant firefly luciferase containing a caspase-3 cleavage site. When apoptosis was induced, caspase-3 cleavage of the biosensor activated firefly luciferase by a factor greater than 25. The assay conveniently detected apoptosis in real time, indicating that it will facilitate drug discovery. We screened ESAT-6 family proteins of Mycobacterium tuberculosis and found that esxA, esxT and esxL induced apoptosis. Further, activation of nuclear factor-κB (NF-κB) and the NF-κB-regulated genes encoding tumor necrosis factor-α (TNF-α) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) participated in esxT-induced apoptosis. We conclude that this assay is useful for high-throughput screening to identify and characterize proteins and drugs that regulate apoptosis.

Mineral Trioxide Aggregate and Portland Cement for Direct Pulp Capping in Dog: A Histopathological Evaluation

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Maryam Bidar

2014-09-01

Full Text Available Background and aims. Mineral trioxide aggregate and calcium hydroxide are considered the gold standard pulp-capping materials. Recently, Portland cement has been introduced with properties similar to those of mineral trioxide aggregate. His-topathological effects of direct pulp capping using mineral trioxide aggregate and Portland cements on dog dental pulp tis-sue were evaluated in the present study. Materials and methods. This histopatological study was carried out on 64 dog premolars. First, the pulp was exposedwith a sterile bur. Then, the exposed pulp was capped with white or gray mineral trioxide aggregates and white or gray Port-land cements in each quadrant and sealed with glass-ionomer. The specimens were evaluated under a light microscope after 6 months. Statistical analysis was carried out using Kruskal-Wallis test. Statistical significance was defined at α=5%. Results. There was no acute inflammation in any of the specimens. Chronic inflammation in white and gray mineral triox-ide aggregates and white and gray Portland cements was reported to be 45.5%, 27.3%, 57.1% and 34.1%, respectively. Al-though the differences were not statistically significant, severe inflammation was observed mostly adjacent to white mineral trioxide aggregate. The largest extent of increased vascularization (45% and the least increase in fibrous tissue were ob-served adjacent to white mineral trioxide aggregate, with no significant differences. In addition, the least calcified tissue formed adjacent to white mineral trioxide aggregate, although the difference was not significant. Conclusion. The materials used in this study were equally effective as pulp protection materials following direct pulp cap-ping in dog teeth.

Iron dysregulation combined with aging prevents sepsis-induced apoptosis.

Science.gov (United States)

Javadi, Pardis; Buchman, Timothy G; Stromberg, Paul E; Turnbull, Isaiah R; Vyas, Dinesh; Hotchkiss, Richard S; Karl, Irene E; Coopersmith, Craig M

2005-09-01

Sepsis, iron loading, and aging cause independent increases in gut epithelial and splenic apoptosis. It is unknown how their combination will affect apoptosis and systemic cytokine levels. Hfe-/- mice (a murine homologue of hemochromatosis) abnormally accumulate iron in their tissues. Aged (24-26 months) or mature (16-18 months) Hfe-/- mice and wild type (WT) littermates were subjected to cecal ligation and puncture (CLP) or sham laparotomy. Intestine, spleen, and blood were harvested 24 h later and assessed for apoptosis and cytokine levels. Gut epithelial and splenic apoptosis were low in both aged septic and sham Hfe-/- mice, regardless of the amount of iron in their diet. Mature septic WT mice had increased apoptosis compared to age-matched sham WT mice. Mature septic Hfe-/- mice had similar levels of intestinal cell death to age-matched septic WT mice but higher levels of splenic apoptosis. Apoptosis was significantly lower in septic aged Hfe-/- mice than septic mature Hfe-/- animals. Interleukin-6 was elevated in septic aged Hfe-/- mice compared to sham mice. Although sepsis, chronic iron dysregulation, and aging each increase gut and splenic apoptosis, their combination yields cell death levels similar to sham animals despite the fact that aged Hfe-/- mice are able to mount an inflammatory response following CLP and mature Hfe-/- mice have elevated sepsis-induced apoptosis. Combining sepsis with two risk factors that ordinarily increase cell death and increase mortality in CLP yields an apoptotic response that could not have been predicted based upon each element in isolation.

N-acetylcysteine protects against cadmium-induced germ cell apoptosis by inhibiting endoplasmic reticulum stress in testes.

Science.gov (United States)

Ji, Yan-Li; Wang, Hua; Zhang, Cheng; Zhang, Ying; Zhao, Mei; Chen, Yuan-Hua; Xu, De-Xiang

2013-03-01

Cadmium (Cd) is a reproductive toxicant that induces germ cell apoptosis in the testes. Previous studies have demonstrated that endoplasmic reticulum (ER) stress is involved in Cd-induced germ cell apoptosis. The aim of the present study was to investigate the effects of N-acetylcysteine (NAC), an antioxidant, on Cd-induced ER stress and germ cell apoptosis in the testes. Male CD-1 mice were intraperitoneally injected with CdCl2 (2.0 mg kg(-1)). As expected, acute Cd exposure induced germ cell apoptosis in the testes, as determined by terminal dUTP nick-end labelling (TUNEL). However, the administration of NAC alleviated Cd-induced germ cell apoptosis in the testes. Further analysis showed that NAC attenuated the Cd-induced upregulation of testicular glucose-regulated protein 78 (GRP78), an important ER molecular chaperone. Moreover, NAC inhibited the Cd-induced phosphorylation of testicular eukaryotic translation initiation factor 2α (eIF2α), a downstream target of the double-stranded RNA-activated kinase-like ER kinase (PERK) pathway. In addition, NAC blocked the Cd-induced activation of testicular X binding protein (XBP)-1, indicating that NAC attenuates the Cd-induced ER stress and the unfolded protein response (UPR). Interestingly, NAC almost completely prevented the Cd-induced elevation of C/EBP homologous protein (CHOP) and phosphorylation of c-Jun N-terminal kinase (JNK), two components of the ER stress-mediated apoptotic pathway. In conclusion, NAC protects against Cd-induced germ cell apoptosis by inhibiting endoplasmic reticulum stress in the testes.

Irigenin sensitizes TRAIL-induced apoptosis via enhancing pro-apoptotic molecules in gastric cancer cells.

Science.gov (United States)

Xu, Ying; Gao, Cheng-Cheng; Pan, Zhen-Guo; Zhou, Chuan-Wen

2018-02-12

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) holds promising value for cancer therapy due to its capacity to induce apoptosis in cancer cells. Nevertheless, TRAIL therapy is greatly hampered by its resistance. Irigenin (Iri), isoflavonoids, can be isolated from the rhizome of Belamcanda chinensis, and has been shown anti-cancer properties. In this study, we explored if Iri could enhance TRAIL-regulated apoptosis in TRAIL resistant gastric cancer cells. Iri significantly potentiated TRAIL-triggered cytotoxicity. Iri alone and TRAIL alone showed no effective role in apoptosis induction, whereas combined treatment with Iri and TRAIL markedly induced apoptosis in cancer cells, as evidenced by the up-regulation of cleaved Caspase-8/-9/-3 and PARP. Additionally, the sensitization to TRAIL was along with the enhancement of pro-apoptotic proteins, including FAS-associated protein with death domain (FADD), death receptor 5 (DR5) and Bax. And suppressing FADD, DR5 and Bax by si RNA significantly reduced the apoptosis and enhanced the cell viability induced by the co-application of Iri and TRAIL. Moreover, the sensitization to TRAIL was accompanied by the decrease of Cellular-FLICE inhibitory protein (c-FLIP), Bcl-2 and Survivin. Additionally, Iri could sensitize TRAIL to produce reactive oxygen species (ROS). Pre-treatment of N-acetyl-cysteine (NAC), ROS scavenger, attenuated Iri plus TRAIL-induced apoptosis and improved cell viability. Finally, combination of Iri and TRAIL inhibited tumor growth in the xenograft model. Collectively, our present study gave new insights into the effects of Iri on potentiating TRAIL-sensitivity, and suggested that Iri could be a potential candidate for sensitizer of TRAIL-resistant cancer cell treatment. Copyright © 2018. Published by Elsevier Inc.

Herbal Medicine as Inducers of Apoptosis in Cancer Treatment

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Elham Safarzadeh

2014-12-01

Full Text Available Cancer is uncontrolled growth of abnormal cells in the body. Nowadays, cancer is considered as a human tragedy and one of the most prevalent diseases in the wide, and its mortality resulting from cancer is being increased. It seems necessary to identify new strategies to prevent and treat such a deadly disease. Control survival and death of cancerous cell are important strategies in the management and therapy of cancer. Anticancer agents should kill the cancerous cell with the minimal side effect on normal cells that is possible through the induction of apoptosis. Apoptosis is known as programmed cell death in both normal and damaged tissues. This process includes some morphologically changes in cells such as rapid condensation and budding of the cell, formation of membrane-enclosed apoptotic bodies with well-preserved organelles. Induction of apoptosis is one of the most important markers of cytotoxic antitumor agents. Some natural compounds including plants induce apoptotic pathways that are blocked in cancer cells through various mechanisms in cancer cells. Multiple surveys reported that people with cancer commonly use herbs or herbal products. Vinca Alkaloids, Texans, podo phyllotoxin, Camptothecins have been clinically used as Plant derived anticancer agents. The present review summarizes the literature published so far regarding herbal medicine used as inducers of apoptosis in cancer.

Dopamine induces neutrophil apoptosis through a dopamine D-1 receptor-independent mechanism.

LENUS (Irish Health Repository)

Sookhai, S

2012-02-03

BACKGROUND: For the normal resolution of an acute inflammatory response, neutrophil (PMN) apoptosis is essential to maintain immune homeostasis and to limit inappropriate host tissue damage. A delay in PMN apoptosis has been implicated in the pathogenesis of the systemic inflammatory response syndrome (SIRS). Dopamine, a biogenic amine with known cardiovascular and neurotransmitter properties, is used in patients with SIRS to maintain hemodynamic stability. We sought to determine whether dopamine may also have immunoregulatory properties capable of influencing PMN apoptosis, function, and activation state in patients with SIRS. METHODS: PMNs were isolated from healthy volunteers and patients with SIRS and treated with varying doses of dopamine and a dopamine D-1 receptor agonist, fenoldopam. PMN apoptosis was assessed every 6 hours with use of propidium iodide DNA staining and PMN function was assessed with use of respiratory burst activity, phagocytosis ability, and CD11a, CD11b, and CD18 receptor expression as functional markers. RESULTS: There was a significant delay in PMN apotosis in patients with SIRS compared with controls. Treatment of isolated PMNs from both healthy controls and patients with SIRS with 10 and 100 mumol\\/L dopamine induced apoptosis. PMN ingestive and cytocidal capacity were both decreased in patients with SIRS compared with controls. Treatment with dopamine significantly increased phagocytic function. Fenoldopam did not induce PMN apoptosis. CONCLUSION: Our data demonstrate for the first time that dopamine induces PMN apoptosis and modulates PMN function both in healthy controls and in patients with SIRS. These results indicate that dopamine may be beneficial during SIRS through a nonhemodynamic PMN-dependent proapoptotic mechanism.

A reactive oxygen species activation mechanism contributes to JS-K-induced apoptosis in human bladder cancer cells.

Science.gov (United States)

Qiu, Mingning; Chen, Lieqian; Tan, Guobin; Ke, Longzhi; Zhang, Sai; Chen, Hege; Liu, Jianjun

2015-10-13

Reactive oxygen species (ROS) and cellular oxidant stress are regulators of cancer cells. The alteration of redox status, which is induced by increased generation of ROS, results in increased vulnerability to oxidative stress. The aim of this study is to investigate the influence of O2-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K, C13H16N6O8) on proliferation and apoptosis in bladder cancer cells and explored possible ROS-related mechanisms. Our results indicated that JS-K could suppress bladder cancer cell proliferation in a concentration- and time-dependent manner and induce apoptosis and ROS accumulation in a concentration-dependent manner. With increasing concentrations of JS-K, expression of proteins that are involved in cell apoptosis increased in a concentration-dependent manner. Additionally, the antioxidant N-acetylcysteine (NAC) reversed JS-K-induced cell apoptosis; conversely, the prooxidant oxidized glutathione (GSSG) exacerbated JS-K-induced cell apoptosis. Furthermore, we found that nitrites, which were generated from the oxidation of JS-K-released NO, induced apoptosis in bladder cancer cells to a lower extent through the ROS-related pathway. In addition, JS-K was shown to enhance the chemo-sensitivity of doxorubicin in bladder cancer cells. Taken together, the data suggest that JS-K-released NO induces bladder cancer cell apoptosis by increasing ROS levels, and nitrites resulting from oxidation of NO have a continuous apoptosis-inducing effect.

Fungal secondary metabolites rasfonin induces autophagy, apoptosis and necroptosis in renal cancer cell line

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Hui Sun

2016-04-01

Full Text Available Rasfonin (A304 is a fungal natural product isolated from the fermentation substrate of Talaromyces sp. 3656-A1, which was named according to its activity against the small G-protein Ras. In a former study, we demonstrated that it induced autophagy and apoptosis; however, whether rasfonin activated necroptosis remained unknown. Moreover, the interplay among different cell death processes induced by rasfonin was unexplored. In the present study, we revealed that, in addition of promoting autophagy and caspase-dependent apoptosis, rasfonin also activated necroptosis. Nectrostatin-1 (Nec-1, an inhibitor of necroptosis, affected rasfonin-induced autophagy in a time-dependent manner concurring with an increased caspase-dependent apoptosis. The aforementioned results were confirmed by knockdown of receptor-interacting protein 1 (RIP1, a crucial necrostatin-1-targeted adaptor kinase mediating cell death and survival. Taken together, the data presented indicate that rasfonin activates various cell death pathways, and RIP1 plays a critical role in rasfonin-induced autophagy and apoptosis.

Kurarinol induces hepatocellular carcinoma cell apoptosis through suppressing cellular signal transducer and activator of transcription 3 signaling

International Nuclear Information System (INIS)

Shu, Guangwen; Yang, Jing; Zhao, Wenhao; Xu, Chan; Hong, Zongguo; Mei, Zhinan; Yang, Xinzhou

2014-01-01

Kurarinol is a flavonoid isolated from roots of the medical plant Sophora flavescens. However, its cytotoxic activity against hepatocellular carcinoma (HCC) cells and toxic effects on mammalians remain largely unexplored. Here, the pro-apoptotic activities of kurarinol on HCC cells and its toxic impacts on tumor-bearing mice were evaluated. The molecular mechanisms underlying kurarinol-induced HCC cell apoptosis were also investigated. We found that kurarinol dose-dependently provoked HepG2, Huh-7 and H22 HCC cell apoptosis. In addition, kurarinol gave rise to a considerable decrease in the transcriptional activity of signal transducer and activator of transcription 3 (STAT3) in HCC cells. Suppression of STAT3 signaling is involved in kurarinol-induced HCC cell apoptosis. In vivo studies showed that kurarinol injection substantially induced transplanted H22 cell apoptosis with low toxic impacts on tumor-bearing mice. Similarly, the transcriptional activity of STAT3 in transplanted tumor tissues was significantly suppressed after kurarinol treatment. Collectively, our current research demonstrated that kurarinol has the capacity of inducing HCC cell apoptosis both in vitro and in vivo with undetectable toxic impacts on the host. Suppressing STAT3 signaling is implicated in kurarinol-mediated HCC cell apoptosis. - Highlights: • Kurarinol induces hepatocellular carcinoma (HCC) cell apoptosis. • Kurarinol induces HCC cell apoptosis via inhibiting STAT3. • Kurarinol exhibits low toxic effects on tumor-bearing animals

Late A-bomb effects on proliferation and mitotic inhibition of T- and B-lymphocytes

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Kazuo; Yoshimoto, Yasuhiko; Sasagawa, Sumiko; Sakatani, Tatsuichiro; Macchi, M; Fujikura, Toshio; Pirofsky, B; Hamada, Tadao

1984-11-01

In order to investigate late effects of ionization radiation and aging on T- and B-lymphocytes, mitotic ability of T- and B-lymphocytes in the peripheral blood of 266 A-bomb survivors was examined by determining the incorporation of (/sup 3/H)-thymidine. Phytohemagglutinin (PHA) and pokeweed mitogen (PWM) were used as inducers. Furthermore, mitotic inhibition of lymphocytes induced by a lymphatic inhibitor which was in part prepared from ulex seed extracts (USE) was examined. A decreased reaction of peripheral lymphocytes to PHA was seen in men exposed to 100-199 rad; a decreased reaction to PWM was seen in women exposed to more than 200 rad. According to the age group at examination, these decreased reactions were remarkable in men aged 60 years or younger and women aged 60 years or older. Among men less than 60-year-old exposed to 100-199 rad, PWM-induced mitosis of lymphocytes tended to be inhibited remarkably by USE. These results suggest the involvement of late A-bomb effects in mitotic regulation of T- and B-lymphocytes of aged A-bomb survivors.

Resveratrol induces growth arrest and apoptosis through activation of FOXO transcription factors in prostate cancer cells.

Directory of Open Access Journals (Sweden)

Qinghe Chen

2010-12-01

Full Text Available Resveratrol, a naturally occurring phytopolyphenol compound, has attracted extensive interest in recent years because of its diverse pharmacological characteristics. Although resveratrol possesses chemopreventive properties against several cancers, the molecular mechanisms by which it inhibits cell growth and induces apoptosis have not been clearly understood. The present study was carried out to examine whether PI3K/AKT/FOXO pathway mediates the biological effects of resveratrol.Resveratrol inhibited the phosphorylation of PI3K, AKT and mTOR. Resveratrol, PI3K inhibitors (LY294002 and Wortmannin and AKT inhibitor alone slightly induced apoptosis in LNCaP cells. These inhibitors further enhanced the apoptosis-inducing potential of resveratrol. Overexpression of wild-type PTEN slightly induced apoptosis. Wild type PTEN and PTEN-G129E enhanced resveratrol-induced apoptosis, whereas PTEN-G129R had no effect on proapoptotic effects of resveratrol. Furthermore, apoptosis-inducing potential of resveratrol was enhanced by dominant negative AKT, and inhibited by wild-type AKT and constitutively active AKT. Resveratrol has no effect on the expression of FKHR, FKHRL1 and AFX genes. The inhibition of FOXO phosphorylation by resveratrol resulted in its nuclear translocation, DNA binding and transcriptional activity. The inhibition of PI3K/AKT pathway induced FOXO transcriptional activity resulting in induction of Bim, TRAIL, p27/KIP1, DR4 and DR5, and inhibition of cyclin D1. Similarly, resveratrol-induced FOXO transcriptional activity was further enhanced when activation of PI3K/AKT pathway was blocked. Over-expression of phosphorylation deficient mutants of FOXO proteins (FOXO1-TM, FOXO3A-TM and FOXO4-TM induced FOXO transcriptional activity, which was further enhanced by resveratrol. Inhibition of FOXO transcription factors by shRNA blocked resveratrol-induced upregulation of Bim, TRAIL, DR4, DR5, p27/KIP1 and apoptosis, and inhibition of cyclin D1 by

An in vivo analysis of Cr6+ induced biochemical, genotoxicological and transcriptional profiling of genes related to oxidative stress, DNA damage and apoptosis in liver of fish, Channa punctatus (Bloch, 1793).

Science.gov (United States)

Awasthi, Yashika; Ratn, Arun; Prasad, Rajesh; Kumar, Manoj; Trivedi, Sunil P

2018-07-01

Present study was designed to assess the hexavalent chromium (Cr 6+ ) mediated oxidative stress that induces DNA damage and apoptosis in adult fish, Channa punctatus (35 ± 3.0 g; 14.5 ± 1.0 cm; Actinopterygii). Fishes were maintained in three groups for 15, 30 and 45 d of exposure periods. They were treated with 5% (Group T1) and 10% (Group T2) of 96 h-LC 50 of chromium trioxide (Cr 6+ ). Controls were run for the similar duration. A significant (p < 0.05) increment in the activities of antioxidant enzymes, SOD and CAT in liver tissues of the exposed fish evinces the persistence of oxidative stress. A significant (p < 0.05) increase in induction of micronuclei (MN) coupled with transcriptional responses of target genes related to antioxidant enzymes, DNA damage and apoptosis (sod, cat, gsr, nox-1, p53, bax, bcl-2, apaf-1 and casp3a) establishes the impact of oxidative stress due to in vivo, Cr 6+ accumulation in liver as compared to control (0 mg/L), in a dose and exposure-dependent manner. Initially, the increased level of reactive oxygen species (ROS) in liver coincided with that of enhanced mRNA expression of antioxidant enzymes, sod, cat, gsr and nox-1 but, later, the overproduction of ROS, after 45 d of exposure of Cr 6+ , resulted in a significant (p < 0.05) up-regulation of p53. Our findings also unveil that the up-regulation of bax, apaf-1 and casp3a and down-regulation of bcl-2 are associated with Cr 6+ -induced oxidative stress mediated-apoptosis in liver of test fish. Aforesaid molecular markers can, thus, be efficiently utilized for bio-monitoring of aquatic regimes and conservation of fish biodiversity. Copyright © 2018 Elsevier B.V. All rights reserved.

VCC-1 over-expression inhibits cisplatin-induced apoptosis in HepG2 cells

International Nuclear Information System (INIS)

Zhou, Zhitao; Lu, Xiao; Zhu, Ping; Zhu, Wei; Mu, Xia; Qu, Rongmei; Li, Ming

2012-01-01

Highlights: ► VCC-1 is hypothesized to be associated with carcinogenesis. ► Levels of VCC-1 are increased significantly in HCC. ► Over-expression of VCC-1 could promotes cellular proliferation rate. ► Over-expression of VCC-1 inhibit the cisplatin-provoked apoptosis in HepG2 cells. ► VCC-1 plays an important role in control the tumor growth and apoptosis. -- Abstract: Vascular endothelial growth factor-correlated chemokine 1 (VCC-1), a recently described chemokine, is hypothesized to be associated with carcinogenesis. However, the molecular mechanisms by which aberrant VCC-1 expression determines poor outcomes of cancers are unknown. In this study, we found that VCC-1 was highly expressed in hepatocellular carcinoma (HCC) tissue. It was also associated with proliferation of HepG2 cells, and inhibition of cisplatin-induced apoptosis of HepG2 cells. Conversely, down-regulation of VCC-1 in HepG2 cells increased cisplatin-induced apoptosis of HepG2 cells. In summary, these results suggest that VCC-1 is involved in cisplatin-induced apoptosis of HepG2 cells, and also provides some evidence for VCC-1 as a potential cellular target for chemotherapy.

Sensitization to UV-induced apoptosis by the histone deacetylase inhibitor trichostatin A (TSA)

International Nuclear Information System (INIS)

Kim, Myoung Sook; Baek, Jin Hyen; Chakravarty, Devulapalli; Sidransky, David; Carrier, France

2005-01-01

UV-induced apoptosis is a protective mechanism that is primarily caused by DNA damage. Cyclobutane pyrimidine dimers (CPD) and 6-4 photoproducts are the main DNA adducts triggered by UV radiation. Because the formation of DNA lesions in the chromatin is modulated by the structure of the nucleosomes, we postulated that modification of chromatin compaction could affect the formation of the lesions and consequently apoptosis. To verify this possibility we treated human colon carcinoma RKO cells with the histone deacetylase inhibitor trichostatin A (TSA) prior to exposure to UV radiation. Our data show that pre-treatment with TSA increased UV killing efficiency by more than threefold. This effect correlated with increased formation of CPDs and consequently apoptosis. On the other hand, TSA treatment after UV exposure rather than before had no more effect than UV radiation alone. This suggests that a primed (opened) chromatin status is required to sensitize the cells. Moreover, TSA sensitization to UV-induced apoptosis is p53 dependent. p53 and acetylation of the core histones may thus contribute to UV-induced apoptosis by modulating the formation of DNA lesions on chromatin

Naringin prevents ovariectomy-induced osteoporosis and promotes osteoclasts apoptosis through the mitochondria-mediated apoptosis pathway

Energy Technology Data Exchange (ETDEWEB)

Li, Fengbo [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China); Graduate School of Tianjin Medical University, No. 22, Qixiangtai Street, Heping District, Tianjin 300070 (China); Sun, Xiaolei; Ma, Jianxiong [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China); Ma, Xinlong, E-mail: gengxiao502@163.com [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China); Zhao, Bin; Zhang, Yang; Tian, Peng [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China); Li, Yanjun [Graduate School of Tianjin Medical University, No. 22, Qixiangtai Street, Heping District, Tianjin 300070 (China); Han, Zhe [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China)

2014-09-26

Highlights: • Naringin possesses many pharmacological activities, promotes the proliferation of osteoblast. • Undecalcified histological obtain dynamic parameters of callus formation and remodeling. • Naringin regulate osteoclast apoptosis by mitochondrial pathway. - Abstract: Naringin, the primary active compound of the traditional Chinese medicine Rhizoma drynariae, possesses many pharmacological activities. The present study is an effort to explore the anti-osteoporosis potential of naringin in vivo and in vitro. In vivo, we used ovariectomized rats to clarify the mechanisms by which naringin anti-osteoporosis. In vitro, we used osteoclasts to investigate naringin promotes osteoclasts apoptosis. Naringin was effective at enhancing BMD, trabecular thickness, bone mineralization, and mechanical strength in a dose-dependent manner. The result of RT-PCR analysis revealed that naringin down-regulated the mRNA expression levels of BCL-2 and up-regulated BAX, caspase-3 and cytochrome C. In addition, naringin significantly reduced the bone resorption area in vitro. These findings suggest that naringin promotes the apoptosis of osteoclasts by regulating the activity of the mitochondrial apoptosis pathway and prevents OVX-induced osteoporosis in rats.

Naringin prevents ovariectomy-induced osteoporosis and promotes osteoclasts apoptosis through the mitochondria-mediated apoptosis pathway

International Nuclear Information System (INIS)

Li, Fengbo; Sun, Xiaolei; Ma, Jianxiong; Ma, Xinlong; Zhao, Bin; Zhang, Yang; Tian, Peng; Li, Yanjun; Han, Zhe

2014-01-01

Highlights: • Naringin possesses many pharmacological activities, promotes the proliferation of osteoblast. • Undecalcified histological obtain dynamic parameters of callus formation and remodeling. • Naringin regulate osteoclast apoptosis by mitochondrial pathway. - Abstract: Naringin, the primary active compound of the traditional Chinese medicine Rhizoma drynariae, possesses many pharmacological activities. The present study is an effort to explore the anti-osteoporosis potential of naringin in vivo and in vitro. In vivo, we used ovariectomized rats to clarify the mechanisms by which naringin anti-osteoporosis. In vitro, we used osteoclasts to investigate naringin promotes osteoclasts apoptosis. Naringin was effective at enhancing BMD, trabecular thickness, bone mineralization, and mechanical strength in a dose-dependent manner. The result of RT-PCR analysis revealed that naringin down-regulated the mRNA expression levels of BCL-2 and up-regulated BAX, caspase-3 and cytochrome C. In addition, naringin significantly reduced the bone resorption area in vitro. These findings suggest that naringin promotes the apoptosis of osteoclasts by regulating the activity of the mitochondrial apoptosis pathway and prevents OVX-induced osteoporosis in rats

The role of autophagy in THP-1 macrophages resistance to HIV- vpr-induced apoptosis

Energy Technology Data Exchange (ETDEWEB)

Zhou, Hua-ying, E-mail: zhouhuaying_2004@126.com; Zheng, Yu-huang; He, Yan; Chen, Zi; He, Bo

2017-02-01

Macrophages are resistant to cell death and are one of HIV reservoirs. HIV viral protein Vpr has the potential to promote infection of and survival of macrophages, which could be a highly significant factor in the development and/or maintenance of macrophage viral reservoirs. However, the impact of vpr on macrophages resistance to apoptosis is yet to be comprehended. Autophagy is a cell survival mechanism under stress state. In this study, we investigated whether autophagy is involved in macrophages resistant to vpr-induced apoptosis. Using the THP1 macrophages, we studied the interconnection between macrophages resistance to apoptosis and autophagy. We found that vpr is able to trigger autophagy in transfected THP-1 macrophages confirmed by electron microscopy (EM) and western blot analysis, and inhibition of autophagy with 3MA increased vpr-induced apoptosis. The results indicate that autophagy may be responsible for maintenance of macrophage HIV reservoirs. - Highlights: • HIV Vpr is able to trigger autophagy in transfected THP-1 macrophages. • Autophagy inhibition increases vpr-transfected THP1-macrophages apoptosis. • Autophagy is involved in THP-1 macrophages resistant to vpr-induced apoptosis.

Taxane-Induced Peripheral Neurotoxicity

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Roser Velasco

2015-04-01

Full Text Available Taxane-derived agents are chemotherapy drugs widely employed in cancer treatment. Among them, paclitaxel and docetaxel are most commonly administered, but newer formulations are being investigated. Taxane antineoplastic activity is mainly based on the ability of the drugs to promote microtubule assembly, leading to mitotic arrest and apoptosis in cancer cells. Peripheral neurotoxicity is the major non-hematological adverse effect of taxane, often manifested as painful neuropathy experienced during treatment, and it is sometimes irreversible. Unfortunately, taxane-induced neurotoxicity is an uncertainty prior to the initiation of treatment. The present review aims to dissect current knowledge on real incidence, underlying pathophysiology, clinical features and predisposing factors related with the development of taxane-induced neuropathy.

The Common Inhalational Anesthetic Sevoflurane Induces Apoptosis and Increases β-Amyloid Protein Levels

Science.gov (United States)

Dong, Yuanlin; Zhang, Guohua; Zhang, Bin; Moir, Robert D.; Xia, Weiming; Marcantonio, Edward R.; Culley, Deborah J.; Crosby, Gregory; Tanzi, Rudolph E.; Xie, Zhongcong

2009-01-01

Objective: To assess the effects of sevoflurane, the most commonly used inhalation anesthetic, on apoptosis and β-amyloid protein (Aβ) levels in vitro and in vivo. Subjects: Naive mice, H4 human neuroglioma cells, and H4 human neuroglioma cells stably transfected to express full-length amyloid precursor protein. Interventions: Human H4 neuroglioma cells stably transfected to express full-length amyloid precursor protein were exposed to 4.1% sevoflurane for 6 hours. Mice received 2.5% sevoflurane for 2 hours. Caspase-3 activation, apoptosis, and Aβ levels were assessed. Results: Sevoflurane induced apoptosis and elevated levels of β-site amyloid precursor protein-cleaving enzyme and Aβ in vitro and in vivo. The caspase inhibitor Z-VAD decreased the effects of sevoflurane on apoptosis and Aβ. Sevoflurane-induced caspase-3 activation was attenuated by the γ-secretase inhibitor L-685,458 and was potentiated by Aβ. These results suggest that sevoflurane induces caspase activation which, in turn, enhances β-site amyloid precursor protein–cleaving enzyme and Aβ levels. Increased Aβ levels then induce further rounds of apoptosis. Conclusions: These results suggest that inhalational anesthetic sevoflurane may promote Alzheimer disease neuropathogenesis. If confirmed in human subjects, it may be prudent to caution against the use of sevoflurane as an anesthetic, especially in those suspected of possessing excessive levels of cerebral Aβ. PMID:19433662

The ganglioside GM3 is associated with cisplatin-induced apoptosis in human colon cancer cells.

Directory of Open Access Journals (Sweden)

Tae-Wook Chung

Full Text Available Cisplatin (cis-diamminedichloroplatinum, CDDP is a well-known chemotherapeutic agent for the treatment of several cancers. However, the precise mechanism underlying apoptosis of cancer cells induced by CDDP remains unclear. In this study, we show mechanistically that CDDP induces GM3-mediated apoptosis of HCT116 cells by inhibiting cell proliferation, and increasing DNA fragmentation and mitochondria-dependent apoptosis signals. CDDP induced apoptosis within cells through the generation of reactive oxygen species (ROS, regulated the ROS-mediated expression of Bax, Bcl-2, and p53, and induced the degradation of the poly (ADP-ribosyl polymerase (PARP. We also checked expression levels of different gangliosides in HCT116 cells in the presence or absence of CDDP. Interestingly, among the gangliosides, CDDP augmented the expression of only GM3 synthase and its product GM3. Reduction of the GM3 synthase level through ectopic expression of GM3 small interfering RNA (siRNA rescued HCT116 cells from CDDP-induced apoptosis. This was evidenced by inhibition of apoptotic signals by reducing ROS production through the regulation of 12-lipoxigenase activity. Furthermore, the apoptotic sensitivity to CDDP was remarkably increased in GM3 synthase-transfected HCT116 cells compared to that in controls. In addition, GM3 synthase-transfected cells treated with CDDP exhibited an increased accumulation of intracellular ROS. These results suggest the CDDP-induced oxidative apoptosis of HCT116 cells is mediated by GM3.

Anti-mitotic potential of 7-diethylamino-3(2′-benzoxazolyl)-coumarin in 5-fluorouracil-resistant human gastric cancer cell line SNU620/5-FU

International Nuclear Information System (INIS)

Kim, Nam Hyun; Kim, Su-Nam; Oh, Joa Sub; Lee, Seokjoon; Kim, Yong Kee

2012-01-01

Highlights: ► DBC exerts antiproliferative potential against 5FU-resistant human gastric cancer cells. ► This effect is mediated by destabilization of microtubules and subsequent mitotic arrest. ► DBC enhances apoptosis via caspase activation and downregulation of antiapoptotic genes. -- Abstract: In this study, we investigate an anti-mitotic potential of the novel synthetic coumarin-based compound, 7-diethylamino-3(2′-benzoxazolyl)-coumarin, in 5-fluorouracil-resistant human gastric cancer cell line SNU-620-5FU and its parental cell SNU-620. It exerts the anti-proliferative effects with similar potencies against both cancer cells, which is mediated by destabilization of microtubules and subsequent mitotic arrest. Furthermore, this compound enhances caspase-dependent apoptotic cell death via decreased expression of anti-apoptotic genes. Taken together, our data strongly support anti-mitotic potential of 7-diethylamino-3(2′-benzoxazolyl)-coumarin against drug-resistant cancer cells which will prompt us to further develop as a novel microtubule inhibitor for drug-resistant cancer chemotherapy.

Effect of head-irradiation upon epidermal mitotic activity during wound healing in the adrenalectomized mice

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Kobayashi, Koshi

1977-01-01

Epidermal mitotic activity during wound healing was estimated both in the adrenalectomized, head-irradiated mice and in the adrenalectomized, non-irradiated mice, and was compared with those obtained previously from the unoperated, head-irradiated mice. It was found that head-irradiation caused a mitotic depression to a much smaller extent in the adrenalectomized mice than it did in the unoperated mice, though adrenalectomy itself had exerted a great inhibitory effect upon the mitosis induced by an injury. Whether this abscopal effect of head-irradiation upon the mitotic activity was mediated via the adrenals, and whether in the adrenalectomized mice the head-irradiation acted to increase epidermal response to injury, making the mitotic pattern of adrenalectomized mice to come near that of control mice were discussed. (auth.)