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Sample records for autophagy inducing agent

  1. Inducing autophagy

    DEFF Research Database (Denmark)

    Harder, Lea M; Bunkenborg, Jakob; Andersen, Jens S.

    2014-01-01

    catabolism, which has recently been found to induce autophagy in an MTOR independent way and support cancer cell survival. In this study, quantitative phosphoproteomics was applied to investigate the initial signaling events linking ammonia to the induction of autophagy. The MTOR inhibitor rapamycin was used...... as a reference treatment to emphasize the differences between an MTOR-dependent and -independent autophagy-induction. By this means 5901 phosphosites were identified of which 626 were treatment-specific regulated and 175 were coregulated. Investigation of the ammonia-specific regulated sites supported that MTOR...

  2. Anesthetic Agents and Neuronal Autophagy. What We Know and What We Don't.

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    Xu, Lili; Shen, Jianjun; McQuillan, Patrick M; Hu, Zhiyong

    2018-01-01

    Ethanol is known to have both γ-Aminobutyric acid agonist and Nmethyl- D-aspartate antagonist characteristics similar to commonly used volatile anesthetic agents. Recent evidence demonstrates that autophagy can reduce the development of ethanol induced neurotoxicity. Recent studies have found that general anesthesia can cause longterm impairment of both mitochondrial morphogenesis and synaptic transmission in the developing rat brain, both of which are accompanied by enhanced autophagy activity. Autophagy may play an important role in general anesthetic mediated neurotoxicity. This review outlines the role of autophagy in the development of anesthetic related neurotoxicity and includes an explanation of the role of autophagy in neuronal cell survival and death, the relationship between anesthetic agents and neuronal autophagy, possible molecular and cellular mechanisms underlying general anesthetic agent induced activation of neuronal autophagy in the developing brain, and potential therapeutic approaches aimed at modulating autophagic pathways. In a time- and concentration-dependent pattern, general anesthetic agents can disrupt intracellular calcium homeostasis which enhances both autophagy and apoptosis activation. The degree of neural cell injury may be ultimately determined by the interplay between autophagy and apoptosis. It appears likely that the increase in calcium flux associated with some anesthetic agents disrupts lysosomal function. This results in an over-activation of endosomal- lysosomal trafficking causing mitochondrial damage, reactive oxygen species upregulation, and lipid peroxidation. Autophagy may play a role in the development of anesthetic related neurotoxicity. Understanding this may lead to strategies or therapies aimed at preventing or ameliorating general anesthetic agent mediated neurotoxicity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Activation of RARα induces autophagy in SKBR3 breast cancer cells and depletion of key autophagy genes enhances ATRA toxicity.

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    Brigger, D; Schläfli, A M; Garattini, E; Tschan, M P

    2015-08-27

    All-trans retinoic acid (ATRA), a pan-retinoic acid receptor (RAR) agonist, is, along with other retinoids, a promising therapeutic agent for the treatment of a variety of solid tumors. On the one hand, preclinical studies have shown promising anticancer effects of ATRA in breast cancer; on the other hand, resistances occurred. Autophagy is a cellular recycling process that allows the degradation of bulk cellular contents. Tumor cells may take advantage of autophagy to cope with stress caused by anticancer drugs. We therefore wondered if autophagy is activated by ATRA in mammary tumor cells and if modulation of autophagy might be a potential novel treatment strategy. Indeed, ATRA induces autophagic flux in ATRA-sensitive but not in ATRA-resistant human breast cancer cells. Moreover, using different RAR agonists as well as RARα-knockdown breast cancer cells, we demonstrate that autophagy is dependent on RARα activation. Interestingly, inhibition of autophagy in breast cancer cells by either genetic or pharmacological approaches resulted in significantly increased apoptosis under ATRA treatment and attenuated epithelial differentiation. In summary, our findings demonstrate that ATRA-induced autophagy is mediated by RARα in breast cancer cells. Furthermore, inhibition of autophagy results in enhanced apoptosis. This points to a potential novel treatment strategy for a selected group of breast cancer patients where ATRA and autophagy inhibitors are applied simultaneously.

  4. Zinc starvation induces autophagy in yeast.

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    Kawamata, Tomoko; Horie, Tetsuro; Matsunami, Miou; Sasaki, Michiko; Ohsumi, Yoshinori

    2017-05-19

    Zinc is an essential nutrient for all forms of life. Within cells, most zinc is bound to protein. Because zinc serves as a catalytic or structural cofactor for many proteins, cells must maintain zinc homeostasis under severely zinc-deficient conditions. In yeast, the transcription factor Zap1 controls the expression of genes required for uptake and mobilization of zinc, but to date the fate of existing zinc-binding proteins under zinc starvation remains poorly understood. Autophagy is an evolutionarily conserved cellular degradation/recycling process in which cytoplasmic proteins and organelles are sequestered for degradation in the vacuole/lysosome. In this study, we investigated how autophagy functions under zinc starvation. Zinc depletion induced non-selective autophagy, which is important for zinc-limited growth. Induction of autophagy by zinc starvation was not directly related to transcriptional activation of Zap1. Instead, TORC1 inactivation directed zinc starvation-induced autophagy. Abundant zinc proteins, such as Adh1, Fba1, and ribosomal protein Rpl37, were degraded in an autophagy-dependent manner. But the targets of autophagy were not restricted to zinc-binding proteins. When cellular zinc is severely depleted, this non-selective autophagy plays a role in releasing zinc from the degraded proteins and recycling zinc for other essential purposes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Lipopolysaccharide (LPS)-Induced Autophagy Is Responsible for Enhanced Osteoclastogenesis.

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    Sul, Ok-Joo; Park, Hyun-Jung; Son, Ho-Jung; Choi, Hye-Seon

    2017-11-30

    We hypothesized that inflammation affects number and activity of osteoclasts (OCs) via enhancing autophagy. Lipopolysaccharide (LPS) induced autophagy, osteoclastogenesis, and cytoplasmic reactive oxygen species (ROS) in bone marrow-derived macrophages that were pre-stimulated with receptor activator of nuclear factor-κB ligand. An autophagy inhibitor, 3-methyladenine (3-MA) decreased LPS-induced OC formation and bone resorption, indicating that autophagy is responsible for increasing number and activity of OCs upon LPS stimulus. Knockdown of autophagy-related protein 7 attenuated the effect of LPS on OC-specific genes, supporting a role of LPS as an autophagy inducer in OC. Removal of ROS decreased LPS-induced OC formation as well as autophagy. However, 3-MA did not affect LPS-induced ROS levels, suggesting that ROS act upstream of phosphatidylinositol-4,5-bisphosphate 3-kinase in LPS-induced autophagy. Our results suggest the possible use of autophagy inhibitors targeting OCs to reduce inflammatory bone loss.

  6. Spermidine and resveratrol induce autophagy by distinct pathways converging on the acetylproteome

    DEFF Research Database (Denmark)

    Morselli, Eugenia; Mariño, Guillermo; Bennetzen, Martin V

    2011-01-01

    Autophagy protects organelles, cells, and organisms against several stress conditions. Induction of autophagy by resveratrol requires the nicotinamide adenine dinucleotide-dependent deacetylase sirtuin 1 (SIRT1). In this paper, we show that the acetylase inhibitor spermidine stimulates autophagy...... independent of SIRT1 in human and yeast cells as well as in nematodes. Although resveratrol and spermidine ignite autophagy through distinct mechanisms, these compounds stimulate convergent pathways that culminate in concordant modifications of the acetylproteome. Both agents favor convergent deacetylation...... and acetylation reactions in the cytosol and in the nucleus, respectively. Both resveratrol and spermidine were able to induce autophagy in cytoplasts (enucleated cells). Moreover, a cytoplasm-restricted mutant of SIRT1 could stimulate autophagy, suggesting that cytoplasmic deacetylation reactions dictate...

  7. Kaempferol induces hepatocellular carcinoma cell death via endoplasmic reticulum stress-CHOP-autophagy signaling pathway.

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    Guo, Haiqing; Lin, Wei; Zhang, Xiangying; Zhang, Xiaohui; Hu, Zhongjie; Li, Liying; Duan, Zhongping; Zhang, Jing; Ren, Feng

    2017-10-10

    Kaempferol is a flavonoid compound that has gained widespread attention due to its antitumor functions. However, the underlying mechanisms are still not clear. The present study investigated the effect of kaempferol on hepatocellular carcinoma and its underlying mechanisms. Kaempferol induced autophagy in a concentration- and time-dependent manner in HepG2 or Huh7 cells, which was evidenced by the significant increase of autophagy-related genes. Inhibition of autophagy pathway, through 3-methyladenine or Atg7 siRNA, strongly diminished kaempferol-induced apoptosis. We further hypothesized that kaempferol can induce autophagy via endoplasmic reticulum (ER) stress pathway. Indeed, blocking ER stress by 4-phenyl butyric acid (4-PBA) or knockdown of CCAAT/enhancer-binding protein homologous protein (CHOP) with siRNA alleviated kaempferol-induced HepG2 or Huh7 cells autophagy; while transfection with plasmid overexpressing CHOP reversed the effect of 4-PBA on kaempferol-induced autophagy. Our results demonstrated that kaempferol induced hepatocarcinoma cell death via ER stress and CHOP-autophagy signaling pathway; kaempferol may be used as a potential chemopreventive agent for patients with hepatocellular carcinoma.

  8. Guttiferone K induces autophagy and sensitizes cancer cells to nutrient stress-induced cell death.

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    Wu, Man; Lao, Yuanzhi; Xu, Naihan; Wang, Xiaoyu; Tan, Hongsheng; Fu, Wenwei; Lin, Zhixiu; Xu, Hongxi

    2015-09-15

    Medicinal plants have long been an excellent source of pharmaceutical agents. Autophagy, a catabolic degradation process through lysosomes, plays an important role in tumorigenesis and cancer therapy. Through a screen designed to identify autophagic regulators from a library of natural compounds, we found that Guttiferone K (GUTK) can activate autophagy in several cancer cell lines. The objective of this study is to investigate the mechanism by which GUTK sensitizes cancer cells to cell death in nutrient starvation condition. Cell death analysis was performed by propidium iodide staining with flow cytometry or Annexin V-FITC/PI staining assay. DCFH-DA staining was used for intracellular ROS measurement. Protein levels were analyzed by western blot analysis. Cell viability was measured by MTT assay. Exposure to GUTK was observed to markedly induce GFP-LC3 puncta formation and activate the accumulation of LC3-II and the degradation of p62 in HeLa cells, suggesting that GUTK is an autophagy inducer. Importantly, hydroxychloroquine, an autophagy inhibitor, was found to significantly prevent GUTK-induced cell death in nutrient starvation conditions, suggesting that the cell death observed is largely dependent on autophagy. We further provide evidence that GUTK inhibits Akt phosphorylation, thereby inhibiting the mTOR pathway in cancer cells during nutrient starvation. In addition, GUTK causes the accumulation of reactive oxygen species (ROS) and the phosphorylation of JNK in EBSS, which may mediate both autophagy and apoptosis. These data indicate that GUTK sensitizes cancer cells to nutrient stress-induced cell death though Akt/mTOR dependent autophagy pathway. Copyright © 2015 The Authors. Published by Elsevier GmbH.. All rights reserved.

  9. Isoliquiritigenin Induces Autophagy and Inhibits Ovarian Cancer Cell Growth

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    Hsin-Yuan Chen

    2017-09-01

    Full Text Available Ovarian cancer is one of the commonest gynecologic malignancies, which has a poor prognosis for patients at the advanced stage. Isoliquiritigenin (ISL, an active flavonoid component of the licorice plant, previously demonstrated antioxidant, anti-inflammatory, and tumor suppressive effects. In this study, we investigated the antitumor effect of ISL on human ovarian cancer in vitro using the human ovarian cancer cell lines, OVCAR5 and ES-2, as model systems. Our results show that ISL significantly inhibited the viability of cancer cells in a concentration- and time-dependent manner. Flow cytometry analysis indicated that ISL induced G2/M phase arrest. Furthermore, the expression of cleaved PARP, cleaved caspase-3, Bax/Bcl-2 ratio, LC3B-II, and Beclin-1 levels were increased in western blot analysis. To clarify the role of autophagy and apoptosis in the effect of ISL, we used the autophagy inhibitor—3-methyladenine (3-MA to attenuate the punctate fluorescence staining pattern of the p62/sequestosome 1 (SQSTM1, red fluorescence and LC3 (green fluorescence proteins after ISL treatment, and 3-MA inhibited the cytotoxicity of ISL. These findings provide new information about the link between ISL-induced autophagy and apoptosis and suggest that ISL is a candidate agent for the treatment of human ovarian cancer.

  10. Xylitol induces cell death in lung cancer A549 cells by autophagy.

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    Park, Eunjoo; Park, Mi Hee; Na, Hee Sam; Chung, Jin

    2015-05-01

    Xylitol is a widely used anti-caries agent that has anti-inflammatory effects. We have evaluated the potential of xylitol in cancer treatment. It's effects on cell proliferation and cytotoxicity were measured by MTT assay and LDH assay. Cell morphology and autophagy were examined by immunostaining and immunoblotting. Xylitol inhibited cell proliferation in a dose-dependent manner in these cancer cells: A549, Caki, NCI-H23, HCT-15, HL-60, K562, and SK MEL-2. The IC50 of xylitol in human gingival fibroblast cells was higher than in cancer cells, indicating that it is more specific for cancer cells. Moreover, xylitol induced autophagy in A549 cells that was inhibited by 3-methyladenine, an autophagy inhibitor. These results indicate that xylitol has potential in therapy against lung cancer by inhibiting cell proliferation and inducing autophagy of A549 cells.

  11. Antioxidant Supplement Inhibits Skeletal Muscle Constitutive Autophagy rather than Fasting-Induced Autophagy in Mice

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    Zhengtang Qi

    2014-01-01

    Full Text Available In this study, we tested the hypothesis that NAC administration leads to reduced oxidative stress and thus to decreased expression of autophagy markers in young mice. Our results reveal that NAC administration results in reduced muscle mRNA levels of several autophagy markers, including Beclin-1, Atg7, LC3, Atg9, and LAMP2. However, NAC supplement fails to block the activation of skeletal muscle autophagy in response to fasting, because fasting significantly increases the mRNA level of several autophagy markers and LC3 lipidation. We further examined the effects of NAC administration on mitochondrial antioxidant capacity in fed and 24-hour fasted mice. Our results clearly show that NAC administration depresses the expression of manganese superoxide dismutase (MnSOD and TP53-induced glycolysis and apoptosis regulator (TIGAR, both of which play a predominant antioxidant role in mitochondria by reducing ROS level. In addition, we found no beneficial effect of NAC supplement on muscle mass but it can protect from muscle loss in response to fasting. Collectively, our findings indicate that ROS is required for skeletal muscle constitutive autophagy, rather than starvation-induced autophagy, and that antioxidant NAC inhibits constitutive autophagy by the regulation of mitochondrial ROS production and antioxidant capacity.

  12. Acute ethanol exposure-induced autophagy-mediated cardiac injury via activation of the ROS-JNK-Bcl-2 pathway.

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    Zhu, Zhongxin; Huang, Yewei; Lv, Lingchun; Tao, Youli; Shao, Minglong; Zhao, Congcong; Xue, Mei; Sun, Jia; Niu, Chao; Wang, Yang; Kim, Sunam; Cong, Weitao; Mao, Wei; Jin, Litai

    2018-02-01

    Binge drinking is associated with increased cardiac autophagy, and often triggers heart injury. Given the essential role of autophagy in various cardiac diseases, this study was designed to investigate the role of autophagy in ethanol-induced cardiac injury and the underlying mechanism. Our study showed that ethanol exposure enhanced the levels of LC3-II and LC3-II positive puncta and promoted cardiomyocyte apoptosis in vivo and in vitro. In addition, we found that ethanol induced autophagy and cardiac injury largely via the sequential triggering of reactive oxygen species (ROS) accumulation, activation of c-Jun NH2-terminal kinase (JNK), phosphorylation of Bcl-2, and dissociation of the Beclin 1/Bcl-2 complex. By contrast, inhibition of ethanol-induced autophagic flux with pharmacologic agents in the hearts of mice and cultured cells significantly alleviated ethanol-induced cardiomyocyte apoptosis and heart injury. Elimination of ROS with the antioxidant N-acetyl cysteine (NAC) or inhibition of JNK with the JNK inhibitor SP600125 reduced ethanol-induced autophagy and subsequent autophagy-mediated apoptosis. Moreover, metallothionein (MT), which can scavenge reactive oxygen and nitrogen species, also attenuated ethanol-induced autophagy and cell apoptosis in MT-TG mice. In conclusion, our findings suggest that acute ethanol exposure induced autophagy-mediated heart toxicity and injury mainly through the ROS-JNK-Bcl-2 signaling pathway. © 2017 Wiley Periodicals, Inc.

  13. Autophagy protects gastric mucosal epithelial cells from ethanol-induced oxidative damage via mTOR signaling pathway.

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    Chang, Weilong; Bai, Jie; Tian, Shaobo; Ma, Muyuan; Li, Wei; Yin, Yuping; Deng, Rui; Cui, Jinyuan; Li, Jinjin; Wang, Guobin; Zhang, Peng; Tao, Kaixiong

    2017-05-01

    Alcohol abuse is an important cause of gastric mucosal epithelial cell injury and gastric ulcers. A number of studies have demonstrated that autophagy, an evolutionarily conserved cellular mechanism, has a protective effect on cell survival. However, it is not known whether autophagy can protect gastric mucosal epithelial cells against the toxic effects of ethanol. In the present study, gastric mucosal epithelial cells (GES-1 cells) and Wistar rats were treated with ethanol to detect the adaptive response of autophagy. Our results demonstrated that ethanol exposure induced gastric mucosal epithelial cell damage, which was accompanied by the downregulation of mTOR signaling pathway and activation of autophagy. Suppression of autophagy with pharmacological agents resulted in a significant increase of GES-1 cell apoptosis and gastric mucosa injury, suggesting that autophagy could protect cells from ethanol toxicity. Furthermore, we evaluated the cellular oxidative stress response following ethanol treatment and found that autophagy induced by ethanol inhibited generation of reactive oxygen species and degradation of antioxidant and lipid peroxidation. In conclusion, these findings provide evidence that ethanol can activate autophagy via downregulation of the mTOR signaling pathway, serving as an adaptive mechanism to ameliorate oxidative damage induced by ethanol in gastric mucosal epithelial cells. Therefore, modifying autophagy may provide a therapeutic strategy against alcoholic gastric mucosa injury. Impact statement The effect and mechanism of autophagy on ethanol-induced cell damage remain controversial. In this manuscript, we report the results of our study demonstrating that autophagy can protect gastric mucosal epithelial cells against ethanol toxicity in vitro and in vivo. We have shown that ethanol can activate autophagy via downregulation of the mTOR signaling pathway, serving as an adaptive mechanism to ameliorate ethanol-induced oxidative damage in

  14. Autophagy contributes to gefitinib-induced glioma cell growth inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Cheng-Yi [Department of Surgery, Fong-Yuan Hospital, Taichung 420, Taiwan (China); Graduate Institute of Pharmaceutical Science and Technology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan (China); Kuan, Yu-Hsiang [Department of Pharmacology, School of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Pharmacy, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China); Ou, Yen-Chuan; Li, Jian-Ri [Division of Urology, Taichung Veterans General Hospital, Taichung 407, Taiwan (China); Wu, Chih-Cheng [Department of Anesthesiology, Taichung Veterans General Hospital, Taichung 407, Taiwan (China); Department of Financial and Computational Mathematics, Providence University, Taichung 433, Taiwan (China); Pan, Pin-Ho [Department of Pediatrics, Tungs’ Taichung MetroHarbor Hospital, Taichung 435, Taiwan (China); Chen, Wen-Ying [Department of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan (China); Huang, Hsuan-Yi [Department of Surgery, Fong-Yuan Hospital, Taichung 420, Taiwan (China); Chen, Chun-Jung, E-mail: cjchen@vghtc.gov.tw [Department of Medical Research, Taichung Veterans General Hospital, Taichung 407, Taiwan (China); Institute of Biomedical Sciences, National Chung Hsing University, Taichung 402, Taiwan (China); Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung 402, Taiwan (China); Center for General Education, Tunghai University, Taichung 407, Taiwan (China); Department of Nursing, HungKuang University, Taichung 433, Taiwan (China)

    2014-09-10

    Epidermal growth factor receptor tyrosine kinase inhibitors, including gefitinib, have been evaluated in patients with malignant gliomas. However, the molecular mechanisms involved in gefitinib-mediated anticancer effects against glioma are incompletely understood. In the present study, the cytostatic potential of gefitinib was demonstrated by the inhibition of glioma cell growth, long-term clonogenic survival, and xenograft tumor growth. The cytostatic consequences were accompanied by autophagy, as evidenced by monodansylcadaverine staining of acidic vesicle formation, conversion of microtubule-associated protein-1 light chain 3-II (LC3-II), degradation of p62, punctate pattern of GFP-LC3, and conversion of GFP-LC3 to cleaved-GFP. Autophagy inhibitor 3-methyladenosine and chloroquine and genetic silencing of LC3 or Beclin 1 attenuated gefitinib-induced growth inhibition. Gefitinib-induced autophagy was not accompanied by the disruption of the Akt/mammalian target of rapamycin signaling. Instead, the activation of liver kinase-B1/AMP-activated protein kinase (AMPK) signaling correlated well with the induction of autophagy and growth inhibition caused by gefitinib. Silencing of AMPK suppressed gefitinib-induced autophagy and growth inhibition. The crucial role of AMPK activation in inducing glioma autophagy and growth inhibition was further supported by the actions of AMP mimetic AICAR. Gefitinib was shown to be capable of reducing the proliferation of glioma cells, presumably by autophagic mechanisms involving AMPK activation. - Highlights: • Gefitinib causes cytotoxic and cytostatic effect on glioma. • Gefitinib induces autophagy. • Gefitinib causes cytostatic effect through autophagy. • Gefitinib induces autophagy involving AMPK.

  15. Autophagy Regulates Colistin-Induced Apoptosis in PC-12 Cells

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    Zhang, Ling; Zhao, Yonghao; Ding, Wenjian; Jiang, Guozheng; Lu, Ziyin; Li, Li; Wang, Jinli

    2015-01-01

    Colistin is a cyclic cationic polypeptide antibiotic with activity against multidrug-resistant Gram-negative bacteria. Our recent study demonstrated that colistin induces apoptosis in primary chick cortex neurons and PC-12 cells. Although apoptosis and autophagy have different impacts on cell fate, there is a complex interaction between them. Autophagy plays an important role as a homeostasis regulator by removing excessive or unnecessary proteins and damaged organelles. The aim of the present study was to investigate the modulation of autophagy and apoptosis regulation in PC-12 cells in response to colistin treatment. PC-12 cells were exposed to colistin (125 to 250 μg/ml), and autophagy was detected by visualization of monodansylcadaverine (MDC)-labeled vacuoles, LC3 (microtubule-associated protein 1 light chain 3) immunofluorescence microscopic examination, and Western blotting. Apoptosis was measured by flow cytometry, Hoechst 33258 staining, and Western blotting. Autophagosomes were observed after treatment with colistin for 12 h, and the levels of LC3-II gene expression were determined; observation and protein levels both indicated that colistin induced a high level of autophagy. Colistin treatment also led to apoptosis in PC-12 cells, and the level of caspase-3 expression increased over the 24-h period. Pretreatment of cells with 3-methyladenine (3-MA) increased colistin toxicity in PC-12 cells remarkably. However, rapamycin treatment significantly increased the expression levels of LC3-II and beclin 1 and decreased the rate of apoptosis of PC-12 cells. Our results demonstrate that colistin induced autophagy and apoptosis in PC-12 cells and that the latter was affected by the regulation of autophagy. It is very likely that autophagy plays a protective role in the reduction of colistin-induced cytotoxicity in neurons. PMID:25645826

  16. Natural Compounds from Herbs that can Potentially Execute as Autophagy Inducers for Cancer Therapy

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    Shian-Ren Lin

    2017-07-01

    Full Text Available Accumulated evidence indicates that autophagy is a response of cancer cells to various anti-cancer therapies. Autophagy is designated as programmed cell death type II, and is characterized by the formation of autophagic vacuoles in the cytoplasm. Numerous herbs, including Chinese herbs, have been applied to cancer treatments as complementary and alternative medicines, supplements, or nutraceuticals to dampen the side or adverse effects of chemotherapy drugs. Moreover, the tumor suppressive actions of herbs and natural products induced autophagy that may lead to cell senescence, increase apoptosis-independent cell death or complement apoptotic processes. Hereby, the underlying mechanisms of natural autophagy inducers are cautiously reviewed in this article. Additionally, three natural compounds—curcumin, 16-hydroxycleroda-3,13-dien-15,16-olide, and prodigiosin—are presented as candidates for autophagy inducers that can trigger cell death in a supplement or alternative medicine for cancer therapy. Despite recent advancements in therapeutic drugs or agents of natural products in several cancers, it warrants further investigation in preclinical and clinical studies.

  17. Ulmus davidiana Nakai induces apoptosis and autophagy on non-small cell lung cancer cells.

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    Hong, Soon-Oh; Choi, In Keun; Jeong, Wonsik; Lee, Se Ryeon; Sung, Hwa Jung; Hong, Seong Su; Seo, Jae Hong

    2017-04-18

    Ulmus davidiana Nakai (UDN) is frequently used in the treatment of cancer in traditional oriental medicine. Although several reports indicate that UDN has inhibitory effects in some cancers, there has been no report on the inhibitory effects of UDN via both autophagy and apoptosis. Cytotoxicity induced by UDN in human non-small cell lung cancer (NSCLC) H-1299 and H-460 cell lines was evaluated using the 2, 3-Bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT) assay and trypan blue exclusion assay. Induction of apoptosis was also investigated using Hoechst staining and annexin-V binding assay and was confirmed with western blot analysis. Induction of autophagy was investigated through observation of autophagy vacuoles under inverted phase-contrast microscopy and was confirmed by observing the formation of autophagy vacuoles under a fluorescence microscope using monodansylcadaverine (MDC) staining and western blot analysis. The in vivo anti-tumorigenic effect of UDN was investigated in an athymic nude mouse xenograft model using H-1299 NSCLC cells. UDN exhibited a marked inhibitory effect on cell growth in H-1299 and H-460 human NSCLC cell lines in a dose- and time-dependent manner in vitro and in vivo. It induced not only apoptosis, but also autophagy in both H-1299 and H-460 cells in a dose-dependent manner. UDN-mediated autophagy led to the accumulation of autophagosome, resulting in apoptosis induction and cell death. From our current knowledge, we are the first to demonstrate that UDN has the potential to induce both autophagy and apoptosis in H-1299 and H-460 human NSCLC cell lines. We suggest that UDN can be considered a potential candidate for lung cancer-specific chemotherapy with efficacy as a cytotoxic agent. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  18. Overweight in elderly people induces impaired autophagy in skeletal muscle.

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    Potes, Yaiza; de Luxán-Delgado, Beatriz; Rodriguez-González, Susana; Guimarães, Marcela Rodrigues Moreira; Solano, Juan J; Fernández-Fernández, María; Bermúdez, Manuel; Boga, Jose A; Vega-Naredo, Ignacio; Coto-Montes, Ana

    2017-09-01

    Sarcopenia is the gradual loss of skeletal muscle mass, strength and quality associated with aging. Changes in body composition, especially in skeletal muscle and fat mass are crucial steps in the development of chronic diseases. We studied the effect of overweight on skeletal muscle tissue in elderly people without reaching obesity to prevent this extreme situation. Overweight induces a progressive protein breakdown reflected as a progressive withdrawal of anabolism against the promoted catabolic state leading to muscle wasting. Protein turnover is regulated by a network of signaling pathways. Muscle damage derived from overweight displayed by oxidative and endoplasmic reticulum (ER) stress induces inflammation and insulin resistance and forces the muscle to increase requirements from autophagy mechanisms. Our findings showed that failure of autophagy in the elderly deprives it to deal with the cell damage caused by overweight. This insufficiently efficient autophagy leads to an accumulation of p62 and NBR1, which are robust markers of protein aggregations. This impaired autophagy affects myogenesis activity. Depletion of myogenic regulatory factors (MRFs) without links to variations in myostatin levels in overweight patients suggest a possible reduction of satellite cells in muscle tissue, which contributes to declined muscle quality. This discovery has important implications that improve the understanding of aged-related atrophy caused by overweight and demonstrates how impaired autophagy is one of the main responsible mechanisms that aggravate muscle wasting. Therefore, autophagy could be an interesting target for therapeutic interventions in humans against muscle impairment diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Ammonia Induces Autophagy through Dopamine Receptor D3 and MTOR

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    Li, Zhiyuan; Ji, Xinmiao; Wang, Wenchao; Liu, Juanjuan; Liang, Xiaofei; Wu, Hong; Liu, Jing; Eggert, Ulrike S.; Liu, Qingsong

    2016-01-01

    Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors. PMID:27077655

  20. Regorafenib delays the proliferation of hepatocellular carcinoma by inducing autophagy.

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    Han, Rui; Li, Shixin

    2018-04-02

    The aim of the present study was to investigate the effects of regorafenib on hepatocellular carcinoma autophagy, thereby supressing the malignancy of HCC. First, HepG2 and Hep3B cell autophagy was investigated using GFP-LC3 transfection after the treatment of regorafenib. Then, the activation of Akt/mTOR signaling was analyzed using western blot. Our data showed that liver cancer cell autophagy was significantly induced by 20 μM regorafenib using GFP-LC3 transfection. Meanwhile, regorafenib-induced cell death could largely be abolished by 3-MA or CQ treatment, suggesting that regorafenib-induced HepG2 cell death was partially dependent on autophagy. Moreover, the activation of Akt/mTOR signaling was inhibited by regorafenib pre-incubation. MTT assay showed the combination use of regorafenib and CDDP led to a stronger growth inhibitory effect on HepG2 and Hep3B cells. In summary, regorafenib may acts an adjunctive therapy for liver cancer patients via modulating autophagy-dependent cell death even when apoptosis resistance is induced in cancer cells.

  1. Oleuropein Aglycone Protects against MAO-A-Induced Autophagy Impairment and Cardiomyocyte Death through Activation of TFEB

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    Caterina Miceli

    2018-01-01

    Full Text Available Age-associated diseases such as neurodegenerative and cardiovascular disorders are characterized by increased oxidative stress associated with autophagy dysfunction. Oleuropein aglycone (OA, the main polyphenol found in olive oil, was recently characterized as an autophagy inducer and a promising agent against neurodegeneration. It is presently unknown whether OA can have beneficial effects in a model of cardiac stress characterized by autophagy dysfunction. Here, we explored the effects of OA in cardiomyocytes with overexpression of monoamine oxidase-A (MAO-A. This enzyme, by degrading catecholamine and serotonin, produces hydrogen peroxide (H2O2, which causes oxidative stress, autophagic flux blockade, and cell necrosis. We observed that OA treatment counteracted the cytotoxic effects of MAO-A through autophagy activation, as displayed by the increase of autophagic vacuoles and autophagy-specific markers (Beclin1 and LC3-II. Moreover, the decrease in autophagosomes and the increase in autolysosomes, indicative of autophagosome-lysosome fusion, suggested a restoration of the defective autophagic flux. Most interestingly, we found that the ability of OA to confer cardioprotection through autophagy induction involved nuclear translocation and activation of the transcriptional factor EB (TFEB. Our data provide strong evidence of the beneficial effects of OA, suggesting its potential use as a nutraceutical agent against age-related pathologies involving autophagy dysfunction, including cardiovascular diseases.

  2. SD118-Xanthocillin X (1, a Novel Marine Agent Extracted from Penicillium commune, Induces Autophagy through the Inhibition of the MEK/ERK Pathway

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    Caiguo Huang

    2012-06-01

    Full Text Available A compound named SD118-xanthocillin X (1 (C18H12N2O2, isolated from Penicillium commune in a deep-sea sediment sample, has been shown to inhibit the growth of several cancer cell lines in vitro. In the present study, we employed a growth inhibition assay and apoptotic analysis to identify the biological effect and detailed mechanism of SD118-xanthocillin X (1 in human hepatocellular carcinoma (HepG2 cells. SD118-xanthocillin X (1 demonstrated a concentration-dependent inhibitory effect on the growth of HepG2 cells and caused slight cellular apoptosis and significantly induced autophagy. Autophagy was detected as early as 12 h by the conversion of microtubule-associated protein 1 light chain 3 (LC3-I to LC3-II, following cleavage and lipid addition to LC3-I. The pharmacological autophagy inhibitor 3-methyladenine largely attenuates the growth inhibition and autophagic effect of SD118-xanthocillin X (1 in HepG2 cells. Our data also indicated that the autophagic effect of SD118-xanthocillin X (1 occurs via the down-regulation of the MEK/ERK signaling pathway and the up-regulated class III PI3K/Beclin 1 signaling pathway.

  3. Macrophage migration inhibitory factor induces vascular leakage via autophagy

    Directory of Open Access Journals (Sweden)

    Hong-Ru Chen

    2015-01-01

    Full Text Available Vascular leakage is an important feature of acute inflammatory shock, which currently has no effective treatment. Macrophage migration inhibitory factor (MIF is a pro-inflammatory cytokine that can induce vascular leakage and plays an important role in the pathogenesis of shock. However, the mechanism of MIF-induced vascular leakage is still unclear. In this study, using recombinant MIF (rMIF, we demonstrated that MIF induced disorganization and degradation of junction proteins and increased the permeability of human endothelial cells in vitro. Western blotting analysis showed that rMIF treatment induced LC3 conversion and p62 degradation. Inhibition of autophagy with a PI3K inhibitor (3-MA, a ROS scavenger (NAC or autophagosomal-lysosomal fusion inhibitors (bafilomycin A1 and chloroquine rescued rMIF-induced vascular leakage, suggesting that autophagy mediates MIF-induced vascular leakage. The potential involvement of other signaling pathways was also studied using different inhibitors, and the results suggested that MIF-induced vascular leakage may occur through the ERK pathway. In conclusion, we showed that MIF triggered autophagic degradation of endothelial cells, resulting in vascular leakage. Inhibition of MIF-induced autophagy may provide therapeutic targets against vascular leakage in inflammatory shock.

  4. Antibiotic drug tigecycline inhibited cell proliferation and induced autophagy in gastric cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chunling; Yang, Liqun; Jiang, Xiaolan [State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716 (China); Xu, Chuan [Division of Scientific Research and Training, General Hospital of PLA Chengdu Military Area Command, Chengdu, Sichuan 610083 (China); Wang, Mei; Wang, Qinrui [State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716 (China); Zhou, Zhansong, E-mail: zhouzhans@sina.com [Institute of Urinary Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Xiang, Zhonghuai [State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716 (China); Cui, Hongjuan, E-mail: hcui@swu.edu.cn [State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400716 (China)

    2014-03-28

    Highlights: • Tigecycline inhibited cell growth and proliferation in human gastric cancer cells. • Tigecycline induced autophagy not apoptosis in human gastric cancer cells. • AMPK/mTOR/p70S6K pathway was activated after tigecycline treatment. • Tigecycline inhibited tumor growth in xenograft model of human gastric cancer cells. - Abstract: Tigecycline acts as a glycylcycline class bacteriostatic agent, and actively resists a series of bacteria, specifically drug fast bacteria. However, accumulating evidence showed that tetracycline and their derivatives such as doxycycline and minocycline have anti-cancer properties, which are out of their broader antimicrobial activity. We found that tigecycline dramatically inhibited gastric cancer cell proliferation and provided an evidence that tigecycline induced autophagy but not apoptosis in human gastric cancer cells. Further experiments demonstrated that AMPK pathway was activated accompanied with the suppression of its downstream targets including mTOR and p70S6K, and ultimately induced cell autophagy and inhibited cell growth. So our data suggested that tigecycline might act as a candidate agent for pre-clinical evaluation in treatment of patients suffering from gastric cancer.

  5. Overcoming Autophagy to Induce Apoptosis in Castration Resistant Prostate Cancer

    Science.gov (United States)

    2015-10-01

    AWARD NUMBER: W81XWH-12-1-0529 TITLE: Overcoming Autophagy to Induce Apoptosis in Castration Resistant Prostate Cancer PRINCIPAL...survival mechanism and led cells to undergo apoptosis . Survival mechanisms elicited by CRPC C4-2B cells when treated with Enza may be blocked by...Targeting cancer cell metabolism: the combination of metformin and 2-deoxyglucose induces p53-dependent apoptosis in prostate cancer cells. Cancer

  6. Estrogen receptor β ligation inhibits Hodgkin lymphoma growth by inducing autophagy

    Science.gov (United States)

    Locatelli, Silvia L.; Ciarlo, Laura; Careddu, Giuseppa; Patrizio, Mario; Ascione, Barbara; Tinari, Antonella; Carlo-Stella, Carmelo; Malorni, Walter; Matarrese, Paola; Ortona, Elena

    2017-01-01

    Although Hodgkin lymphoma (HL) is curable with current therapy, at least 20% of patients relapse or fail to make complete remission. In addition, patients who achieve long-term disease-free survival frequently undergo infertility, secondary malignancies, and cardiac failure, which are related to chemotherapeutic agents and radiation therapies. Hence, new therapeutic strategies able to counteract the HL disease in this important patient population are still a matter of study. Estrogens, in particular 17β-estradiol (E2), have been suggested to play a role in lymphoma cell homeostasis by estrogen receptors (ER) β activation. On these bases, we investigated whether the ligation of ERβ by a selective agonist, the 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN), could impact HL tumor growth. We found that DPN-mediated ERβ activation led to a reduction of in vitro cell proliferation and cell cycle progression by inducing autophagy. In nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice engrafted with HL cells, ERβ activation by DPN was able to reduce lymphoma growth up to 60% and this associated with the induction of tumor cell autophagy. Molecular characterization of ERβ-induced autophagy revealed an overexpression of damage-regulated autophagy modulator 2 (DRAM2) molecule, whose role in autophagy modulation is still debated. After ERβ activation, both DRAM2 and protein 1 light chain 3 (LC3), a key actor in the autophagosome formation, strictly interacted each other and localized at mitochondrial level. Altogether these results suggest that targeting ERβ with selective agonists might affect HL cell proliferation and tumor growth via a mechanism that brings into play DRAM2-dependent autophagic cascade. PMID:28052027

  7. Concanavalin A: A potential anti-neoplastic agent targeting apoptosis, autophagy and anti-angiogenesis for cancer therapeutics

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wen-wen; Yu, Jia-ying; Xu, Huai-long [School of Life Sciences and State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610064 (China); Bao, Jin-ku, E-mail: jinkubao@yahoo.com [School of Life Sciences and State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610064 (China)

    2011-10-22

    Highlights: {yields} ConA induces cancer cell death targeting apoptosis and autophagy. {yields} ConA inhibits cancer cell angiogenesis. {yields} ConA is utilized in pre-clinical and clinical trials. -- Abstract: Concanavalin A (ConA), a Ca{sup 2+}/Mn{sup 2+}-dependent and mannose/glucose-binding legume lectin, has drawn a rising attention for its remarkable anti-proliferative and anti-tumor activities to a variety of cancer cells. ConA induces programmed cell death via mitochondria-mediated, P73-Foxo1a-Bim apoptosis and BNIP3-mediated mitochondrial autophagy. Through IKK-NF-{kappa}B-COX-2, SHP-2-MEK-1-ERK, and SHP-2-Ras-ERK anti-angiogenic pathways, ConA would inhibit cancer cell survival. In addition, ConA stimulates cell immunity and generates an immune memory, resisting to the same genotypic tumor. These biological findings shed light on new perspectives of ConA as a potential anti-neoplastic agent targeting apoptosis, autophagy and anti-angiogenesis in pre-clinical or clinical trials for cancer therapeutics.

  8. MDMA-induced neurotoxicity of serotonin neurons involves autophagy and rilmenidine is protective against its pathobiology.

    Science.gov (United States)

    Mercer, Linda D; Higgins, Gavin C; Lau, Chew L; Lawrence, Andrew J; Beart, Philip M

    2017-05-01

    Toxicity of 3,4-methylenedioxymethamphetamine (MDMA) towards biogenic amine neurons is well documented and in primate brain predominantly affects serotonin (5-HT) neurons. MDMA induces damage of 5-HT axons and nerve fibres and intracytoplasmic inclusions. Whilst its pathobiology involves mitochondrially-mediated oxidative stress, we hypothesised MDMA possessed the capacity to activate autophagy, a proteostatic mechanism for degradation of cellular debris. We established a culture of ventral pons from embryonic murine brain enriched in 5-HT neurons to explore mechanisms of MDMA neurotoxicity and recruitment of autophagy, and evaluated possible neuroprotective actions of the clinically approved agent rilmenidine. MDMA (100 μM-1 mM) reduced cell viability, like rapamycin (RM) and hydrogen peroxide (H 2 O 2 ), in a concentration- and time-dependent manner. Immunocytochemistry revealed dieback of 5-HT arbour: MDMA-induced injury was slower than for RM and H 2 O 2 , neuritic blebbing occurred at 48 and 72 h and Hoechst labelling revealed nuclear fragmentation with 100 μM MDMA. MDMA effected concentration-dependent inhibition of [ 3 H]5-HT uptake with 500 μM MDMA totally blocking transport. Western immunoblotting for microtubule associated protein light chain 3 (LC3) revealed autophagosome formation after treatment with MDMA. Confocal analyses and immunocytochemistry for 5-HT, Hoechst and LC3 confirmed MDMA induced autophagy with abundant LC3-positive puncta within 5-HT neurons. Rilmenidine (1 μM) protected against MDMA-induced injury and image analysis showed full preservation of 5-HT arbours. MDMA had no effect on GABA neurons, indicating specificity of action at 5-HT neurons. MDMA-induced neurotoxicity involves autophagy induction in 5-HT neurons, and rilmenidine via beneficial actions against toxic intracellular events represents a potential treatment for its pathobiology in sustained usage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. SIRT5 regulation of ammonia-induced autophagy and mitophagy

    Science.gov (United States)

    Polletta, Lucia; Vernucci, Enza; Carnevale, Ilaria; Arcangeli, Tania; Rotili, Dante; Palmerio, Silvia; Steegborn, Clemens; Nowak, Theresa; Schutkowski, Mike; Pellegrini, Laura; Sansone, Luigi; Villanova, Lidia; Runci, Alessandra; Pucci, Bruna; Morgante, Emanuela; Fini, Massimo; Mai, Antonello; Russo, Matteo A; Tafani, Marco

    2015-01-01

    In liver the mitochondrial sirtuin, SIRT5, controls ammonia detoxification by regulating CPS1, the first enzyme of the urea cycle. However, while SIRT5 is ubiquitously expressed, urea cycle and CPS1 are only present in the liver and, to a minor extent, in the kidney. To address the possibility that SIRT5 is involved in ammonia production also in nonliver cells, clones of human breast cancer cell lines MDA-MB-231 and mouse myoblast C2C12, overexpressing or silenced for SIRT5 were produced. Our results show that ammonia production increased in SIRT5-silenced and decreased in SIRT5-overexpressing cells. We also obtained the same ammonia increase when using a new specific inhibitor of SIRT5 called MC3482. SIRT5 regulates ammonia production by controlling glutamine metabolism. In fact, in the mitochondria, glutamine is transformed in glutamate by the enzyme glutaminase, a reaction producing ammonia. We found that SIRT5 and glutaminase coimmunoprecipitated and that SIRT5 inhibition resulted in an increased succinylation of glutaminase. We next determined that autophagy and mitophagy were increased by ammonia by measuring autophagic proteolysis of long-lived proteins, increase of autophagy markers MAP1LC3B, GABARAP, and GABARAPL2, mitophagy markers BNIP3 and the PINK1-PARK2 system as well as mitochondrial morphology and dynamics. We observed that autophagy and mitophagy increased in SIRT5-silenced cells and in WT cells treated with MC3482 and decreased in SIRT5-overexpressing cells. Moreover, glutaminase inhibition or glutamine withdrawal completely prevented autophagy. In conclusion we propose that the role of SIRT5 in nonliver cells is to regulate ammonia production and ammonia-induced autophagy by regulating glutamine metabolism. PMID:25700560

  10. Dual PI-3 kinase/mTOR inhibition impairs autophagy flux and induces cell death independent of apoptosis and necroptosis

    Science.gov (United States)

    Button, Robert W.; Vincent, Joseph H.; Strang, Conor J.; Luo, Shouqing

    2016-01-01

    The PI-3 kinase (PI-3K)/mTOR pathway is critical for cell growth and proliferation. Strategies of antagonising this signaling have proven to be detrimental to cell survival. This observation, coupled with the fact many tumours show enhanced growth signaling, has caused dual inhibitors of PI-3K and mTOR to be implicated in cancer treatment, and have thus been studied across various tumour models. Since PI-3K (class-I)/mTOR pathway negatively regulates autophagy, dual inhibitors of PI-3K/mTOR are currently believed to be autophagy activators. However, our present data show that the dual PI-3K/mTOR inhibition (DKI) potently suppresses autophagic flux. We further confirm that inhibition of Vps34/PI3KC3, the class-III PI-3K, causes the blockade to autophagosome-lysosome fusion. Our data suggest that DKI induces cell death independently of apoptosis and necroptosis, whereas autophagy perturbation by DKI may contribute to cell death. Given that autophagy is critical in cellular homeostasis, our study not only clarifies the role of a dual PI-3K/mTOR inhibitor in autophagy, but also suggests that its autophagy inhibition needs to be considered if such an agent is used in cancer chemotherapy. PMID:26814436

  11. The Role of Autophagy in Nanoparticles-Induced Toxicity and Its Related Cellular and Molecular Mechanisms.

    Science.gov (United States)

    Li, Yubin; Ju, Dianwen

    2018-01-01

    In the past decades, nanoparticles have been widely used in industry and pharmaceutical fields for drug delivery, anti-pathogen, and diagnostic imaging purposes because of their unique physicochemical characteristics such as special ultrastructure, dispersity, and effective cellular uptake properties. But the nanotoxicity has been raised over the extensive applications of nanoparticles. Researchers have elucidated series of mechanisms in nanoparticles-induced toxicity, including apoptosis, necrosis, oxidative stress, and autophagy. Among upon mechanisms, autophagy was recently recognized as an important cell death style in various nanoparticles-induced toxicity, but the role of autophagy and its related cellular and molecular mechanisms during nanoparticles-triggered toxicity were still confusing. In the chapter, we briefly introduced the general process of autophagy, summarized the different roles of autophagy in various nanoparticle-treated different in vitro/in vivo models, and deeply analyzed the physicochemical and biochemical (cellular and molecular) mechanisms of autophagy during nanoparticles-induced toxicity through listing and summarizing representative examples. Physicochemical mechanisms mainly include dispersity, size, charge, and surface chemistry; cellular mechanisms primarily focus on lysosome impairment, mitochondria dysfunction, mitophagy, endoplasmic reticulum stress and endoplasmic reticulum autophagy; while molecular mechanisms were mainly including autophagy related signaling pathways, hypoxia-inducible factor, and oxidative stress. This chapter highlighted the important role of autophagy as a critical mechanism in nanoparticles-induced toxicity, and the physicochemical and biochemical mechanisms of autophagy triggered by nanoparticles might be useful for establishing a guideline for the evaluation of nanotoxicology, designing and developing new biosafety nanoparticles in the future.

  12. Lutein Induces Autophagy via Beclin-1 Upregulation in IEC-6 Rat Intestinal Epithelial Cells.

    Science.gov (United States)

    Chang, Chi-Jen; Lin, Ji-Fan; Hsiao, Chien-Yu; Chang, Hsun-Hao; Li, Hsin-Ju; Chang, Hsun-Hsien; Lee, Gon-Ann; Hung, Chi-Feng

    2017-01-01

    Lutein is a carotenoid with anti-oxidant properties. Autophagy, an evolutionarily conserved catabolic cellular pathway for coping with stress conditions, is responsive to reactive oxygen species (ROS) and degrades damaged organelles. We previously demonstrated that lutein can induce anti-oxidant enzymes to relieve methotrexate-induced ROS stress. We therefore hypothesized that lutein, which activates ROS-scavenging enzymes, can also induce autophagy for cell survival. In this study, we demonstrated that lutein treatment attenuated the reduction in cell viability caused by H 2 O 2 . Lutein dose-dependently induced the processing of microtubule-associated protein light chain 3 (LC3)-II, an autophagy marker protein, and accumulation of LC3-positive puncta in rat intestinal IEC-6 cells. Furthermore, (a) direct observation of autophagosome formation through transmission electron microscopy, (b) upregulation of autophagy-related genes including ATG4A, ATG5, ATG7, ATG12, and beclin-1 (BENC1), and (c) increased BECN1/Bcl-2 ratio confirmed the induction of autophagy by lutein. The results revealed that bafilomycin-A1-induced inhibition of autophagy reduced cell viability and increased apoptosis in lutein-treated cells, indicating a protective role of lutein-induced autophagy. Lutein treatment also activated adenosine monophosphate-activated protein kinase (AMPK), c-Jun N-terminal kinase (JNK), and p-38, but had no effects on the induction of extracellular signal-related kinase or inhibition of mTOR; however, the inhibition of activated AMPK, JNK, or p-38 did not attenuate lutein-induced autophagy. Finally, increased BECN1 expression levels were detected in lutein-treated cells, and BECN1 knockdown abolished autophagy induction. These results suggest that lutein-induced autophagy was mediated by the upregulation of BECN1 in IEC-6 cells. We are the first to demonstrate that lutein induces autophagy. Elevated autophagy in lutein-treated IEC-6 cells may have a protective role

  13. Lithium limits trimethyltin-induced cytotoxicity and proinflammatory response in microglia without affecting the concurrent autophagy impairment.

    Science.gov (United States)

    Fabrizi, Cinzia; Pompili, Elena; Somma, Francesca; De Vito, Stefania; Ciraci, Viviana; Artico, Marco; Lenzi, Paola; Fornai, Francesco; Fumagalli, Lorenzo

    2017-02-01

    Trimethyltin (TMT) is a highly toxic molecule present as an environmental contaminant causing neurodegeneration particularly of the limbic system both in humans and in rodents. We recently described the occurrence of impairment in the late stages of autophagy in TMT-intoxicated astrocytes. Here we show that similarly to astrocytes also in microglia, TMT induces the precocious block of autophagy indicated by the accumulation of the autophagosome marker, microtubule associated protein light chain 3. Consistent with autophagy impairment we observe in TMT-treated microglia the accumulation of p62/SQSTM1, a protein specifically degraded through this pathway. Lithium has been proved effective in limiting neurodegenerations and, in particular, in ameliorating symptoms of TMT intoxication in rodents. In our in vitro model, lithium displays a pro-survival and anti-inflammatory action reducing both cell death and the proinflammatory response of TMT-treated microglia. In particular, lithium exerts these activities without reducing TMT-induced accumulation of light chain 3 protein. In fact, the autophagic block imposed by TMT is unaffected by lithium administration. These results are of interest as defects in the execution of autophagy are frequently observed in neurodegenerative diseases and lithium is considered a promising therapeutic agent for these pathologies. Thus, it is relevant that this cation can still maintain its pro-survival and anti-inflammatory role in conditions of autophagy block. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Treatment Induced Autophagy Associated with Tumor Dormancy and Relapse

    Science.gov (United States)

    2016-07-01

    The cells also demonstrated senescence, based on beta galactosidase staining (Figure 1C, lower panels). The induction of autophagy was confirmed...detection of autophagosomes (Panel C, upper portion) and beta galactosidase (β-gal) as a marker of senescence (panel C, lower portion). Induction...8  A. Control    ADR     IR   B. C.   Figure 5. Senescence induced in 4T1cells by Adriamycin and Radiation. Panel A shows beta galactosidase

  15. Cordycepin-induced apoptosis and autophagy in breast cancer cells are independent of the estrogen receptor

    International Nuclear Information System (INIS)

    Choi, Sunga; Lim, Mi-Hee; Kim, Ki Mo; Jeon, Byeong Hwa; Song, Won O.; Kim, Tae Woong

    2011-01-01

    Cordycepin (3-deoxyadenosine), found in Cordyceps spp., has been known to have many therapeutic effects including immunomodulatory, anti-inflammatory, antimicrobial, and anti-aging effects. Moreover, anti-tumor and anti-metastatic effects of cordycepin have been reported, but the mechanism causing cancer cell death is poorly characterized. The present study was designed to investigate whether the mechanisms of cordycepin-induced cell death were associated with estrogen receptor in breast cancer cells. Exposure of both MDA-MB-231 and MCF-7 human breast cancer cells to cordycepin resulted in dose-responsive inhibition of cell growth and reduction in cell viability. The cordycepin-induced cell death in MDA-MB-231 cells was associated with several specific features of the mitochondria-mediated apoptotic pathway, which was confirmed by DNA fragmentation, TUNEL, and biochemical assays. Cordycepin also caused a dose-dependent increase in mitochondrial translocation of Bax, triggering cytosolic release of cytochrome c and activation of caspases-9 and -3. Interestingly, MCF-7 cells showed autophagy-associated cell death, as observed by the detection of an autophagosome-specific protein and large membranous vacuole ultrastructure morphology in the cytoplasm. Cordycepin-induced autophagic cell death has applications in treating MCF-7 cells with apoptotic defects, irrespective of the ER response. Although autophagy has a survival function in tumorigenesis of some cancer cells, autophagy may be important for cordycepin-induced MCF-7 cell death. In conclusion, the results of our study demonstrate that cordycepin effectively kills MDA-MB-231 and MCF-7 human breast cancer cell lines in culture. Hence, further studies should be conducted to determine whether cordycepin will be a clinically useful, ER-independent, chemotherapeutic agent for human breast cancer. -- Highlights: ► We studied the mechanism which cordycepin-induced cell death association with estrogen receptor (ER) in

  16. Cordycepin-induced apoptosis and autophagy in breast cancer cells are independent of the estrogen receptor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sunga [Department of Physiology, School of Medicine, Chungnam National University, Daejeon, 301747 (Korea, Republic of); Lim, Mi-Hee [Department of Biochemistry, Kangwon National University, Gangwon-do, 200701 (Korea, Republic of); Kim, Ki Mo [Diabetic Complications Research Center, Division of Traditional Korean Medicine (TKM) Integrated Research, Korea Institute of Oriental Medicine (KIOM), 305811, Daejeon (Korea, Republic of); Jeon, Byeong Hwa [Department of Physiology, School of Medicine, Chungnam National University, Daejeon, 301747 (Korea, Republic of); Song, Won O. [Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824 (United States); Kim, Tae Woong, E-mail: tawkim@kangwon.ac.kr [Department of Biochemistry, Kangwon National University, Gangwon-do, 200701 (Korea, Republic of)

    2011-12-15

    Cordycepin (3-deoxyadenosine), found in Cordyceps spp., has been known to have many therapeutic effects including immunomodulatory, anti-inflammatory, antimicrobial, and anti-aging effects. Moreover, anti-tumor and anti-metastatic effects of cordycepin have been reported, but the mechanism causing cancer cell death is poorly characterized. The present study was designed to investigate whether the mechanisms of cordycepin-induced cell death were associated with estrogen receptor in breast cancer cells. Exposure of both MDA-MB-231 and MCF-7 human breast cancer cells to cordycepin resulted in dose-responsive inhibition of cell growth and reduction in cell viability. The cordycepin-induced cell death in MDA-MB-231 cells was associated with several specific features of the mitochondria-mediated apoptotic pathway, which was confirmed by DNA fragmentation, TUNEL, and biochemical assays. Cordycepin also caused a dose-dependent increase in mitochondrial translocation of Bax, triggering cytosolic release of cytochrome c and activation of caspases-9 and -3. Interestingly, MCF-7 cells showed autophagy-associated cell death, as observed by the detection of an autophagosome-specific protein and large membranous vacuole ultrastructure morphology in the cytoplasm. Cordycepin-induced autophagic cell death has applications in treating MCF-7 cells with apoptotic defects, irrespective of the ER response. Although autophagy has a survival function in tumorigenesis of some cancer cells, autophagy may be important for cordycepin-induced MCF-7 cell death. In conclusion, the results of our study demonstrate that cordycepin effectively kills MDA-MB-231 and MCF-7 human breast cancer cell lines in culture. Hence, further studies should be conducted to determine whether cordycepin will be a clinically useful, ER-independent, chemotherapeutic agent for human breast cancer. -- Highlights: Black-Right-Pointing-Pointer We studied the mechanism which cordycepin-induced cell death association with

  17. Autophagy as a target for cancer therapy: new developments

    International Nuclear Information System (INIS)

    Carew, Jennifer S; Kelly, Kevin R; Nawrocki, Steffan T

    2012-01-01

    Autophagy is an evolutionarily conserved lysosomal degradation pathway that eliminates cytosolic proteins, macromolecules, organelles, and protein aggregates. Activation of autophagy may function as a tumor suppressor by degrading defective organelles and other cellular components. However, this pathway may also be exploited by cancer cells to generate nutrients and energy during periods of starvation, hypoxia, and stress induced by chemotherapy. Therefore, induction of autophagy has emerged as a drug resistance mechanism that promotes cancer cell survival via self-digestion. Numerous preclinical studies have demonstrated that inhibition of autophagy enhances the activity of a broad array of anticancer agents. Thus, targeting autophagy may be a global anticancer strategy that may improve the efficacy of many standard of care agents. These results have led to multiple clinical trials to evaluate autophagy inhibition in combination with conventional chemotherapy. In this review, we summarize the anticancer agents that have been reported to modulate autophagy and discuss new developments in autophagy inhibition as an anticancer strategy

  18. Kaempferol induces hepatocellular carcinoma cell death via endoplasmic reticulum stress-CHOP-autophagy signaling pathway

    OpenAIRE

    Guo, Haiqing; Lin, Wei; Zhang, Xiangying; Zhang, Xiaohui; Hu, Zhongjie; Li, Liying; Duan, Zhongping; Zhang, Jing; Ren, Feng

    2017-01-01

    Kaempferol is a flavonoid compound that has gained widespread attention due to its antitumor functions. However, the underlying mechanisms are still not clear. The present study investigated the effect of kaempferol on hepatocellular carcinoma and its underlying mechanisms. Kaempferol induced autophagy in a concentration- and time-dependent manner in HepG2 or Huh7 cells, which was evidenced by the significant increase of autophagy-related genes. Inhibition of autophagy pathway, through 3-meth...

  19. A diphenyldiselenide derivative induces autophagy via JNK in HTB-54 lung cancer cells.

    Science.gov (United States)

    Díaz, Marta; González, Roncesvalles; Plano, Daniel; Palop, Juan Antonio; Sanmartín, Carmen; Encío, Ignacio

    2018-01-01

    Symmetric aromatic diselenides are potential anticancer agents with strong cytotoxic activity. In this study, the in vitro anticancer activities of a novel series of diarylseleno derivatives from the diphenyldiselenide (DPDS) scaffold were evaluated. Most of the compounds exhibited high efficacy for inducing cytotoxicity against different human cancer cell lines. DPDS 2, the compound with the lowest mean GI 50 value, induced both caspase-dependent apoptosis and arrest at the G 0 /G 1 phase in acute lymphoblastic leucemia CCRF-CEM cells. Consistent with this, PARP cleavage; enhanced caspase-2, -3, -8 and -9 activity; reduced CDK4 expression and increased levels of p53 were detected in these cells upon DPDS 2 treatment. Mutated p53 expressed in CCRF-CEM cells retains its transactivating activity. Therefore, increased levels of p21 CIP1 and BAX proteins were also detected. On the other hand, DPDS 6, the compound with the highest selectivity index for cancer cells, resulted in G 2 /M cell cycle arrest and caspase-independent cell death in p53 deficient HTB-54 lung cancer cells. Autophagy inhibitors 3-methyladenine, wortmannin and chloroquine inhibited DPDS 6-induced cell death. Consistent with autophagy, increased LC3-II and decreased SQSTM1/p62 levels were detected in HTB-54 cells in response to DPDS 6. Induction of JNK phosphorylation and a reduction in phospho-p38 MAPK were also detected. Moreover, the JNK inhibitor SP600125-protected HTB-54 cells from DPDS 6-induced cell death indicating that JNK activation is involved in DPDS 6-induced autophagy. These results highlight the anticancer effects of these derivatives and warrant future studies examining their clinical potential. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  20. 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.

  1. Idarubicin induces mTOR-dependent cytotoxic autophagy in leukemic cells

    Energy Technology Data Exchange (ETDEWEB)

    Ristic, Biljana [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Bosnjak, Mihajlo [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Arsikin, Katarina [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Mircic, Aleksandar; Suzin-Zivkovic, Violeta [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Bogdanovic, Andrija [Clinic for Hematology, Clinical Centre of Serbia, School of Medicine, University of Belgrade, Belgrade (Serbia); Perovic, Vladimir [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Martinovic, Tamara; Kravic-Stevovic, Tamara; Bumbasirevic, Vladimir [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Trajkovic, Vladimir, E-mail: vtrajkovic@med.bg.ac.rs [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Harhaji-Trajkovic, Ljubica, E-mail: buajk@yahoo.com [Institute for Biological Research, University of Belgrade, Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade (Serbia)

    2014-08-01

    We investigated if the antileukemic drug idarubicin induces autophagy, a process of programmed cellular self-digestion, in leukemic cell lines and primary leukemic cells. Transmission electron microscopy and acridine orange staining demonstrated the presence of autophagic vesicles and intracellular acidification, respectively, in idarubicin-treated REH leukemic cell line. Idarubicin increased punctuation/aggregation of microtubule-associated light chain 3B (LC3B), enhanced the conversion of LC3B-I to autophagosome-associated LC3B-II in the presence of proteolysis inhibitors, and promoted the degradation of the selective autophagic target p62, thus indicating the increase in autophagic flux. Idarubicin inhibited the phosphorylation of the main autophagy repressor mammalian target of rapamycin (mTOR) and its downstream target p70S6 kinase. The treatment with the mTOR activator leucine prevented idarubicin-mediated autophagy induction. Idarubicin-induced mTOR repression was associated with the activation of the mTOR inhibitor AMP-activated protein kinase and down-regulation of the mTOR activator Akt. The suppression of autophagy by pharmacological inhibitors or LC3B and beclin-1 genetic knockdown rescued REH cells from idarubicin-mediated oxidative stress, mitochondrial depolarization, caspase activation and apoptotic DNA fragmentation. Idarubicin also caused mTOR inhibition and cytotoxic autophagy in K562 leukemic cell line and leukocytes from chronic myeloid leukemia patients, but not healthy controls. By demonstrating mTOR-dependent cytotoxic autophagy in idarubicin-treated leukemic cells, our results warrant caution when considering combining idarubicin with autophagy inhibitors in leukemia therapy. - Highlights: • Idarubicin induces autophagy in leukemic cell lines and primary leukemic cells. • Idarubicin induces autophagy by inhibiting mTOR in leukemic cells. • mTOR suppression by idarubicin is associated with AMPK activation and Akt blockade.

  2. A novel protoapigenone analog RY10-4 induces breast cancer MCF-7 cell death through autophagy via the Akt/mTOR pathway

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    Zhang, Xuenong; Wei, Han; Liu, Ziwei; Yuan, Qianying [Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation of Hubei Province, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Wei, Anhua [Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Shi, Du; Yang, Xian [Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation of Hubei Province, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Ruan, Jinlan, E-mail: jinlan8152@163.com [Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation of Hubei Province, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China)

    2013-07-15

    Protoapigenone is a unique flavonoid and enriched in many ferns, showing potent antitumor activity against a broad spectrum of human cancer cell lines. RY10-4, a modified version of protoapigenone, manifested better anti-proliferation activity in human breast cancer cell line MCF-7. The cytotoxicity of RY10-4 against MCF-7 cells is exhibited in both time- and concentration-dependent manners. Here we investigated a novel effect of RY10-4 mediated autophagy in autophagy defect MCF-7 cells. Employing immunofluorescence assay for microtubule-associated protein light-chain 3 (LC3), monodansylcadaverine staining, Western blotting analyses for LC3 and p62 as well as ultrastructural analysis by transmission electron microscopy, we showed that RY10-4 induced autophagy in MCF-7 cells but protoapigenone did not. Meanwhile, inhibition of autophagy by pharmacological and genetic approaches significantly increased the viability of RY10-4 treated cells, suggesting that the autophagy induced by RY10-4 played as a promotion mechanism for cell death. Further studies revealed that RY10-4 suppressed the activation of mTOR and p70S6K via the Akt/mTOR pathway. Our results provided new insights for the mechanism of RY10-4 induced cell death and the cause of RY10-4 showing better antitumor activity than protoapigenone, and supported further evidences for RY10-4 as a lead to design a promising antitumor agent. - Highlights: • We showed that RY10-4 induced autophagy in MCF-7 cells but protoapigenone did not. • Autophagy induced by RY10-4 played as a promotion mechanism for cell death. • RY10-4 induced autophagy in MCF-7 cell through the Akt/mTOR pathway. • We provided new insights for the mechanism of RY10-4 induced cell death.

  3. ROS-induced DNA damage and PARP-1 are required for optimal induction of starvation-induced autophagy

    DEFF Research Database (Denmark)

    Rodríguez-Vargas, José Manuel; Ruiz-Magaña, María José; Ruiz-Ruiz, Carmen

    2012-01-01

    In response to nutrient stress, cells start an autophagy program that can lead to adaptation or death. The mechanisms underlying the signaling from starvation to the initiation of autophagy are not fully understood. In the current study we show that the absence or inactivation of PARP-1 strongly...... delays starvation-induced autophagy. We have found that DNA damage is an early event of starvation-induced autophagy as measured by ¿-H2AX accumulation and comet assay, with PARP-1 knockout cells displaying a reduction in both parameters. During starvation, ROS-induced DNA damage activates PARP-1......, leading to ATP depletion (an early event after nutrient deprivation). The absence of PARP-1 blunted AMPK activation and prevented the complete loss of mTOR activity, leading to a delay in autophagy. PARP-1 depletion favors apoptosis in starved cells, suggesting a pro-survival role of autophagy and PARP-1...

  4. Colchicine induces autophagy and senescence in lung cancer cells at clinically admissible concentration: potential use of colchicine in combination with autophagy inhibitor in cancer therapy.

    Science.gov (United States)

    Bhattacharya, Surela; Das, Amlan; Datta, Satabdi; Ganguli, Arnab; Chakrabarti, Gopal

    2016-08-01

    Colchicine is a well-known and potent microtubule targeting agent, but the therapeutic value of colchicine against cancer is limited by its toxicity against normal cells. But, there is no report of its cytotoxic potential against lung cancer cell, at clinically permissible or lower concentrations, minimally toxic to non-cancerous cells. Hence, in the present study, we investigated the possible mechanism by which the efficacy of colchicine against lung cancer cells at less toxic dose could be enhanced. Colchicine at clinically admissible concentration of 2.5 nM had no cytotoxic effect and caused no G2/M arrest in A549 cells. However, at this concentration, colchicine strongly hindered the reformation of cold depolymerised interphase and spindle microtubule. Colchicine induced senescence and reactive oxygen species mediated autophagy in A549 cells at this concentration. Autophagy inhibitor 3-methyladenine (3-MA) sensitised the cytotoxicity of colchicine in A549 cells by switching senescence to apoptotic death, and this combination had reduced cytotoxicity to normal lung fibroblast cells (WI38). Together, these findings indicated the possible use of colchicine at clinically relevant dose along with autophagy inhibitor in cancer therapy.

  5. Avian metapneumovirus subgroup C induces autophagy through the ATF6 UPR pathway.

    Science.gov (United States)

    Hou, Lei; Wei, Li; Zhu, Shanshan; Wang, Jing; Quan, Rong; Li, Zixuan; Liu, Jue

    2017-10-03

    An increasing number of studies have demonstrated that macroautophagy/autophagy plays an important role in the infectious processes of diverse pathogens. However, it remains unknown whether autophagy is induced in avian metapneumovirus (aMPV)-infected host cells, and, if so, how this occurs. Here, we report that aMPV subgroup C (aMPV/C) induces autophagy in cultured cells. We demonstrated this relationship by detecting classical autophagic features, including the formation of autophagsomes, the presence of GFP-LC3 puncta and the conversation of LC3-I into LC3-II. Also, we used pharmacological regulators and siRNAs targeting ATG7 or LC3 to examine the role of autophagy in aMPV/C replication. The results showed that autophagy is required for efficient replication of aMPV/C. Moreover, infection with aMPV/C promotes autophagosome maturation and induces a complete autophagic process. Finally, the ATF6 pathway, of which one component is the unfolded protein response (UPR), becomes activated in aMPV/C-infected cells. Knockdown of ATF6 inhibited aMPV/C-induced autophagy and viral replication. Collectively, these results not only show that autophagy promotes aMPV/C replication in the cultured cells, but also reveal that the molecular mechanisms underlying aMPV/C-induced autophagy depends on regulation of the ER stress-related UPR pathway.

  6. Pseudolaric acid B induced cell cycle arrest, autophagy and senescence in murine fibrosarcoma l929 cell.

    Science.gov (United States)

    Yu, Jing hua; Liu, Chun yu; Zheng, Gui bin; Zhang, Li Ying; Yan, Ming hui; Zhang, Wen yan; Meng, Xian ying; Yu, Xiao fang

    2013-01-01

    PAB induced various cancer cell apoptosis, cell cycle arrest and senescence. But in cell line murine fibrosarcoma L929, PAB did not induce apoptosis, but autophagy, therefore it was thought by us as a good model to research the relationship of cell cycle arrest, autophagy and senescence bypass apoptosis. Inhibitory ratio was assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analysis. Phase contrast microscopy visualized cell morphology. Hoechst 33258 staining for nuclear change, propidium iodode (PI) staining for cell cycle, monodansylcadaverine (MDC) staining for autophagy, and rodanmine 123 staining for mitochondrial membrane potential (MMP) were measured by fluorescence microscopy or flowcytometry. Apoptosis was determined by DNA ladder test. Protein kinase C (PKC) activity was detected by PKC assay kit. SA-β-galactosidase assay was used to detect senescence. Protein expression was examined by western blot. PAB inhibited L929 cell growth in time-and dose-dependent manner. At 12 h, 80 μmol/L PAB induced obvious mitotic arrest; at 24 h, PAB began to induce autophagy; at 36 h, cell-treated with PAB slip into G1 cell cycle; and 3 d PAB induced senescence. In time sequence PAB induced firstly cell cycle arrest, then autophagy, then slippage into G1 phase, lastly senescence. Senescent cells had high level of autophagy, inhibiting autophagy led to apoptosis, and no senescence. PAB activated PKC activity to induce cell cycle arrest, autophagy and senescence, inhibiting PKC activity suppressed cell cycle arrest, autophagy and senescence. PAB induced cell cycle arrest, autophagy and senescence in murine fibrosarcoma L929 cell through PKC.

  7. Autophagy Protects MC3T3-E1 Cells upon Aluminum-Induced Apoptosis.

    Science.gov (United States)

    Yang, Xu; Zhang, Jian; Ji, Qiang; Wang, Fan; Song, Miao; Li, Yanfei

    2018-03-08

    Aluminum (Al) exposure has adverse effects on osteoblasts, and the effect might be through autophagy-associated apoptosis. In this study, we showed that aluminum trichloride (AlCl 3 ) could induce autophagy in MC3T3-E1 cells, as demonstrated by monodansylcadaverine (MDC) staining and the expressions of the ATG3, ATG5, and ATG9 genes. We found AlCl 3 inhibited MC3T3-E1 cell survival rate and caused apoptosis, as evidenced by CCK-8 assay, Annexin V/PI double staining, and increased expressions of Bcl-2, Bax, and Caspase-3 genes. In addition, increased autophagy induced by rapamycin further attenuated the MC3T3-E1 cell apoptosis rate after AlCl 3 exposure. These results support the hypothesis that autophagy plays a protective role in impeding apoptosis caused by AlCl 3 . Activating autophagy may be a strategy for treatment of Al-induced bone disease.

  8. Rapamycin regulates autophagy and cell adhesion in induced pluripotent stem cells.

    LENUS (Irish Health Repository)

    Sotthibundhu, Areechun

    2016-01-01

    Cellular reprogramming is a stressful process, which requires cells to engulf somatic features and produce and maintain stemness machineries. Autophagy is a process to degrade unwanted proteins and is required for the derivation of induced pluripotent stem cells (iPSCs). However, the role of autophagy during iPSC maintenance remains undefined.

  9. Porcine Epidemic Diarrhea Virus Induces Autophagy to Benefit Its Replication

    Directory of Open Access Journals (Sweden)

    Xiaozhen Guo

    2017-03-01

    Full Text Available The new porcine epidemic diarrhea (PED has caused devastating economic losses to the swine industry worldwide. Despite extensive research on the relationship between autophagy and virus infection, the concrete role of autophagy in porcine epidemic diarrhea virus (PEDV infection has not been reported. In this study, autophagy was demonstrated to be triggered by the effective replication of PEDV through transmission electron microscopy, confocal microscopy, and Western blot analysis. Moreover, autophagy was confirmed to benefit PEDV replication by using autophagy regulators and RNA interference. Furthermore, autophagy might be associated with the expression of inflammatory cytokines and have a positive feedback loop with the NF-κB signaling pathway during PEDV infection. This work is the first attempt to explore the complex interplay between autophagy and PEDV infection. Our findings might accelerate our understanding of the pathogenesis of PEDV infection and provide new insights into the development of effective therapeutic strategies.

  10. Inhibition of autophagy promotes metastasis and glycolysis by inducing ROS in gastric cancer cells.

    Science.gov (United States)

    Qin, Wenjie; Li, Chao; Zheng, Wen; Guo, Qingqu; Zhang, Yuefeng; Kang, Muxing; Zhang, Bo; Yang, Bin; Li, Baozhong; Yang, Haijun; Wu, Yulian

    2015-11-24

    Autophagy defect has been shown to be correlated with malignant phenotype and poor prognosis of human cancers, however, the detailed mechanisms remain obscure. In this study, we investigated the biological changes induced by autophagy inhibition in gastric cancer. We showed that inhibition of autophagy in gastric cancer cells promotes epithelial-mesenchymal transition (EMT) and metastasis, alters metabolic phenotype from mitochondrial oxidative phosphorylation to aerobic glycolysis and converts cell phenotype toward malignant, which maybe further contribute to chemoresistance and poor prognosis of gastric cancer. We also identified that the EMT and metabolism alterations induced by autophagy inhibition were dependent on ROS-NF-κB-HIF-1α pathway. More importantly, scavenging of ROS by the antioxidant N-acetylcysteine (NAC) attenuated activation of NF-κB and HIF-1α in autophagy-deficient gastric cancer cells, and autophagy inhibition induced metastasis and glycolysis were also diminished by NAC in vivo. Taken together, our findings suggested that autophagy defect promotes metastasis and glycolysis of gastric cancer, and antioxidants could be used to improve disease outcome for gastric cancer patients with autophagy defect.

  11. Downregulation of PI3K/Akt/mTOR signaling pathway in curcumin-induced autophagy in APP/PS1 double transgenic mice.

    Science.gov (United States)

    Wang, Chen; Zhang, Xiong; Teng, Zhipeng; Zhang, Tong; Li, Yu

    2014-10-05

    Autophagy is a lysosomal degradation pathway, which is essential for cell survival, proliferation, differentiation and homeostasis. It is well known that beta-amyloid (Aβ) aggregation is one of key characteristics for Alzheimer's disease (AD), which triggers a complex pathological cascade, leading to neurodegeneration. Recent studies have shown that Aβ peptide is generated from amyloid β precursor protein (APP) during autophagic turnover of APP-rich organelles by autophagy. Aβ generation during normal autophagy is subsequently degraded by lysosomes. Curcumin, a nature plant extraction, has been reported to inhibit the generation and deposition of Aβ; however, the underlying mechanisms are not fully understood yet. In the present study, we reported that curcumin treatment not only attenuated cognitive impairment detected by Morris water maze test, but also inhibited the generation of Aβ investigated by immunohistochemistry in APP/PS1 double transgenic AD mice. Moreover, curcumin induced autophagy in the mice, evidenced by LC3 immunofluorescence analysis and western blot assays on LC3. Furthermore, we found that curcumin significantly decreased the expression of Phosphatidylinositol 3-Kinase (PI3K), phosphorylated Akt and rapamycin (mTOR) at protein levels, respectively. Taken together, our data suggests that curcumin inhibits Aβ generation and induces of autophagy by downregulating PI3K/Akt/mTOR signaling pathway, and further shows a neuroprotective effect. Meanwhile curcumin might be a candidate neuroprotective agent for AD patients treatment by inducing autophagy. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Capsaicin Enhances the Drug Sensitivity of Cholangiocarcinoma through the Inhibition of Chemotherapeutic-Induced Autophagy.

    Directory of Open Access Journals (Sweden)

    Zai-Fa Hong

    Full Text Available Cholangiocarcinoma (CCA, a devastating cancer with a poor prognosis, is resistant to the currently available chemotherapeutic agents. Capsaicin, the major pungent ingredient found in hot red chili peppers of the genus Capsicum, suppresses the growth of several malignant cell lines. Our aims were to investigate the role and mechanism of capsaicin with respect to the sensitivity of CCA cells to chemotherapeutic agents. The effect of capsaicin on CCA tumor sensitivity to 5-fluorouracil (5-FU was assessed in vitro in CCA cells and in vivo in a xenograft model. The drug sensitivity of QBC939 to 5-FU was significantly enhanced by capsaicin compared with either agent alone. In addition, the combination of capsaicin with 5-FU was synergistic, with a combination index (CI < 1, and the combined treatment also suppressed tumor growth in the CCA xenograft to a greater extent than 5-FU alone. Further investigation revealed that the autophagy induced by 5-FU was inhibited by capsaicin. Moreover, the decrease in AKT and S6 phosphorylation induced by 5-FU was effectively reversed by capsaicin, indicating that capsaicin inhibits 5-FU-induced autophagy by activating the phosphoinositide 3-kinase (PI3K/protein kinase B (AKT/mammalian target of rapamycin (mTOR pathway in CCA cells. Taken together, these results demonstrate that capsaicin may be a useful adjunct therapy to improve chemosensitivity in CCA. This effect likely occurs via PI3K/AKT/mTOR pathway activation, suggesting a promising strategy for the development of combination drugs for CCA.

  13. Curcumin Inhibits Apoptosis of Chondrocytes through Activation ERK1/2 Signaling Pathways Induced Autophagy

    Directory of Open Access Journals (Sweden)

    Xiaodong Li

    2017-04-01

    Full Text Available Osteoarthritis (OA is an inflammatory disease of load-bearing synovial joints that is currently treated with drugs that exhibit numerous side effects and are only temporarily effective in treating pain, the main symptom of the disease. Consequently, there is an acute need for novel, safe, and more effective chemotherapeutic agents for the treatment of osteoarthritis and related arthritic diseases. Curcumin, the principal curcuminoid and the most active component in turmeric, is a biologically active phytochemical. Evidence from several recent in vitro studies suggests that curcumin may exert a chondroprotective effect through actions such as anti-inflammatory, anti-oxidative stress, and anti-catabolic activity that are critical for mitigating OA disease pathogenesis and symptoms. In the present study, we investigated the protective mechanisms of curcumin on interleukin 1β (IL-1β-stimulated primary chondrocytes in vitro. The treatment of interleukin (IL-1β significantly reduces the cell viability of chondrocytes in dose and time dependent manners. Co-treatment of curcumin with IL-1β significantly decreased the growth inhibition. We observed that curcumin inhibited IL-1β-induced apoptosis and caspase-3 activation in chondrocytes. Curcumin can increase the expression of phosphorylated extracellular signal-regulated kinases 1/2 (ERK1/2, autophagy marker light chain 3 (LC3-II, and Beclin-1 in chondrocytes. The expression of autophagy markers could be decreased when the chondrocytes were incubated with ERK1/2 inhibitor U0126. Our results suggest that curcumin suppresses apoptosis and inflammatory signaling through its actions on the ERK1/2-induced autophagy in chondrocytes. We propose that curcumin should be explored further for the prophylactic treatment of osteoarthritis in humans and companion animals.

  14. Acid-induced autophagy protects human lung cancer cells from apoptosis by activating ER stress.

    Science.gov (United States)

    Xie, Wen-Yue; Zhou, Xiang-Dong; Li, Qi; Chen, Ling-Xiu; Ran, Dan-Hua

    2015-12-10

    An acidic tumor microenvironment exists widely in solid tumors. However, the detailed mechanism of cell survival under acidic stress remains unclear. The aim of this study is to clarify whether acid-induced autophagy exists and to determine the function and mechanism of autophagy in lung cancer cells. We have found that acute low pH stimulated autophagy by increasing LC3-positive punctate vesicles, increasing LC3 II expression levels and reducing p62 protein levels. Additionally, autophagy was inhibited by the addition of Baf or knockdown of Beclin 1, and cell apoptosis was increased markedly. In mouse tumors, the expression of cleaved caspase3 and p62 was enhanced by oral treatment with sodium bicarbonate, which can raise the intratumoral pH. Furthermore, the protein levels of ER stress markers, including p-PERK, p-eIF2α, CHOP, XBP-1s and GRP78, were also increased in response to acidic pH. The antioxidant NAC, which reduces ROS accumulation, alleviated acid-mediated ER stress and autophagy, and knocking down GRP78 reduced autophagy activation under acidic conditions, which suggests that autophagy was induced by acidic pH through ER stress. Taken together, these results indicate that the acidic microenvironment in non-small cell lung cancer cells promotes autophagy by increasing ROS-ER stress, which serves as a survival adaption in this setting. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Hibiscus sabdariffa leaf polyphenolic extract induces human melanoma cell death, apoptosis, and autophagy.

    Science.gov (United States)

    Chiu, Chun-Tang; Hsuan, Shu-Wen; Lin, Hui-Hsuan; Hsu, Cheng-Chin; Chou, Fen-Pi; Chen, Jing-Hsien

    2015-03-01

    Melanoma is the least common but most fatal form of skin cancer. Previous studies have indicated that an aqueous extract of Hibiscus sabdariffa leaves possess hypoglycemic, hypolipidemic, and antioxidant effects. In this study, we want to investigate the anticancer activity of Hibiscus leaf polyphenolic (HLP) extract in melanoma cells. First, HLP was exhibited to be rich in epicatechin gallate (ECG) and other polyphenols. Apoptotic and autophagic activities of HLP and ECG were further evaluated by DAPI stain, cell-cycle analysis, and acidic vascular organelle (AVO) stain. Our results revealed that both HLP and ECG induced the caspases cleavages, Bcl-2 family proteins regulation, and Fas/FasL activation in A375 cells. In addition, we also revealed that the cells presented AVO-positive after HLP treatments. HLP could increase the expressions of autophagy-related proteins autophagy-related gene 5 (ATG5), Beclin1, and light chain 3-II (LC3-II), and induce autophagic cell death in A375 cells. These data indicated that the anticancer effect of HLP, partly contributed by ECG, in A375 cells. HLP potentially could be developed as an antimelanoma agent. © 2015 Institute of Food Technologists®

  16. Rejuvenation of MPTP-induced human neural precursor cell senescence by activating autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Liang [East Hospital, Tongji University School of Medicine, Shanghai (China); Dong, Chuanming [East Hospital, Tongji University School of Medicine, Shanghai (China); Department of Anatomy and Neurobiology, The Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong (China); Sun, Chenxi; Ma, Rongjie; Yang, Danjing [East Hospital, Tongji University School of Medicine, Shanghai (China); Zhu, Hongwen, E-mail: hongwen_zhu@hotmail.com [Tianjin Hospital, Tianjin Academy of Integrative Medicine, Tianjin (China); Xu, Jun, E-mail: xunymc2000@yahoo.com [East Hospital, Tongji University School of Medicine, Shanghai (China)

    2015-08-21

    Aging of neural stem cell, which can affect brain homeostasis, may be caused by many cellular mechanisms. Autophagy dysfunction was found in aged and neurodegenerative brains. However, little is known about the relationship between autophagy and human neural stem cell (hNSC) aging. The present study used 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) to treat neural precursor cells (NPCs) derived from human embryonic stem cell (hESC) line H9 and investigate related molecular mechanisms involved in this process. MPTP-treated NPCs were found to undergo premature senescence [determined by increased senescence-associated-β-galactosidase (SA-β-gal) activity, elevated intracellular reactive oxygen species level, and decreased proliferation] and were associated with impaired autophagy. Additionally, the cellular senescence phenotypes were manifested at the molecular level by a significant increase in p21 and p53 expression, a decrease in SOD2 expression, and a decrease in expression of some key autophagy-related genes such as Atg5, Atg7, Atg12, and Beclin 1. Furthermore, we found that the senescence-like phenotype of MPTP-treated hNPCs was rejuvenated through treatment with a well-known autophagy enhancer rapamycin, which was blocked by suppression of essential autophagy gene Beclin 1. Taken together, these findings reveal the critical role of autophagy in the process of hNSC aging, and this process can be reversed by activating autophagy. - Highlights: • We successfully establish hESC-derived neural precursor cells. • MPTP treatment induced senescence-like state in hESC-derived NPCs. • MPTP treatment induced impaired autophagy of hESC-derived NPCs. • MPTP-induced hESC-derived NPC senescence was rejuvenated by activating autophagy.

  17. Methanolic Extract of Ganoderma lucidum Induces Autophagy of AGS Human Gastric Tumor Cells.

    Science.gov (United States)

    Reis, Filipa S; Lima, Raquel T; Morales, Patricia; Ferreira, Isabel C F R; Vasconcelos, M Helena

    2015-09-29

    Ganoderma lucidum is one of the most widely studied mushroom species, particularly in what concerns its medicinal properties. Previous studies (including those from some of us) have shown some evidence that the methanolic extract of G. lucidum affects cellular autophagy. However, it was not known if it induces autophagy or decreases the autophagic flux. The treatment of a gastric adenocarcinoma cell line (AGS) with the mushroom extract increased the formation of autophagosomes (vacuoles typical from autophagy). Moreover, the cellular levels of LC3-II were also increased, and the cellular levels of p62 decreased, confirming that the extract affects cellular autophagy. Treating the cells with the extract together with lysossomal protease inhibitors, the cellular levels of LC3-II and p62 increased. The results obtained proved that, in AGS cells, the methanolic extract of G. lucidum causes an induction of autophagy, rather than a reduction in the autophagic flux. To our knowledge, this is the first study proving that statement.

  18. Sonodynamic therapy induces the interplay between apoptosis and autophagy in K562 cells through ROS.

    Science.gov (United States)

    Su, Xiaomin; Wang, Pan; Yang, Shuang; Zhang, Kun; Liu, Quanhong; Wang, Xiaobing

    2015-03-01

    Sonodynamic therapy (SDT) is a relatively new approach in the treatment of various cancers including leukemia cells. The aim of this study is to investigate the occurrence of apoptosis and autophagy after treated by protoporphyrin IX (PpIX)-mediated SDT (PpIX-SDT) on human leukemia K562 cells as well as the relationship between them. Firstly, mitochondrial-dependent apoptosis was observed through morphological observation and biochemical analysis. Meanwhile, SDT was shown to induce autophagy in K562 cells, which caused an increase in EGFP-LC3 puncta cells, a conversion of LC3 II/I, formation of acidic vesicular organelles (AVOs) and co-localization between LC3 and LAMP2 (a lysosome marker). Besides, pretreatment with autophagy inhibitor 3-MA or bafilomycin A1 was shown to provide protection against autophagy and to enhance SDT-induced apoptosis and necrosis, while the apoptosis suppressor z-VAD-fmk failed to affect formation of autophagic vacuoles or partially prevented SDT-induced cytotoxicity, which suggested that SDT-induced autophagy functioned as a survival mechanism. Additionally, this study reported apparent apoptosis and autophagy with dependence on intracellular reactive oxygen species (ROS) production. Preliminary data showed that ROS scavenger N-acetylcysteine (NAC) effectively blocked the SDT induced accumulation of ROS, reversed sono-damage, cell apoptosis and autophagy. Taken together, these data indicate that autophagy may be cytoprotective in our experimental system, and the ROS caused by PpIX-SDT treatment may play an important role in initiating apoptosis and autophagy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Andrographolide Analogue Induces Apoptosis and Autophagy Mediated Cell Death in U937 Cells by Inhibition of PI3K/Akt/mTOR Pathway.

    Directory of Open Access Journals (Sweden)

    Deepak Kumar

    Full Text Available Current chemotherapeutic agents based on apoptosis induction are lacking in desired efficacy. Therefore, there is continuous effort to bring about new dimension in control and gradual eradication of cancer by means of ever evolving therapeutic strategies. Various forms of PCD are being increasingly implicated in anti-cancer therapy and the complex interplay among them is vital for the ultimate fate of proliferating cells. We elaborated and illustrated the underlying mechanism of the most potent Andrographolide analogue (AG-4 mediated action that involved the induction of dual modes of cell death-apoptosis and autophagy in human leukemic U937 cells.AG-4 induced cytotoxicity was associated with redox imbalance and apoptosis which involved mitochondrial depolarisation, altered apoptotic protein expressions, activation of the caspase cascade leading to cell cycle arrest. Incubation with caspase inhibitor Z-VAD-fmk or Bax siRNA decreased cytotoxic efficacy of AG-4 emphasising critical roles of caspase and Bax. In addition, AG-4 induced autophagy as evident from LC3-II accumulation, increased Atg protein expressions and autophagosome formation. Pre-treatment with 3-MA or Atg 5 siRNA suppressed the cytotoxic effect of AG-4 implying the pro-death role of autophagy. Furthermore, incubation with Z-VAD-fmk or Bax siRNA subdued AG-4 induced autophagy and pre-treatment with 3-MA or Atg 5 siRNA curbed AG-4 induced apoptosis-implying that apoptosis and autophagy acted as partners in the context of AG-4 mediated action. AG-4 also inhibited PI3K/Akt/mTOR pathway. Inhibition of mTOR or Akt augmented AG-4 induced apoptosis and autophagy signifying its crucial role in its mechanism of action.Thus, these findings prove the dual ability of AG-4 to induce apoptosis and autophagy which provide a new perspective to it as a potential molecule targeting PCD for future cancer therapeutics.

  20. Andrographolide Analogue Induces Apoptosis and Autophagy Mediated Cell Death in U937 Cells by Inhibition of PI3K/Akt/mTOR Pathway.

    Science.gov (United States)

    Kumar, Deepak; Das, Bimolendu; Sen, Rupashree; Kundu, Priyanka; Manna, Alak; Sarkar, Avijit; Chowdhury, Chinmay; Chatterjee, Mitali; Das, Padma

    2015-01-01

    Current chemotherapeutic agents based on apoptosis induction are lacking in desired efficacy. Therefore, there is continuous effort to bring about new dimension in control and gradual eradication of cancer by means of ever evolving therapeutic strategies. Various forms of PCD are being increasingly implicated in anti-cancer therapy and the complex interplay among them is vital for the ultimate fate of proliferating cells. We elaborated and illustrated the underlying mechanism of the most potent Andrographolide analogue (AG-4) mediated action that involved the induction of dual modes of cell death-apoptosis and autophagy in human leukemic U937 cells. AG-4 induced cytotoxicity was associated with redox imbalance and apoptosis which involved mitochondrial depolarisation, altered apoptotic protein expressions, activation of the caspase cascade leading to cell cycle arrest. Incubation with caspase inhibitor Z-VAD-fmk or Bax siRNA decreased cytotoxic efficacy of AG-4 emphasising critical roles of caspase and Bax. In addition, AG-4 induced autophagy as evident from LC3-II accumulation, increased Atg protein expressions and autophagosome formation. Pre-treatment with 3-MA or Atg 5 siRNA suppressed the cytotoxic effect of AG-4 implying the pro-death role of autophagy. Furthermore, incubation with Z-VAD-fmk or Bax siRNA subdued AG-4 induced autophagy and pre-treatment with 3-MA or Atg 5 siRNA curbed AG-4 induced apoptosis-implying that apoptosis and autophagy acted as partners in the context of AG-4 mediated action. AG-4 also inhibited PI3K/Akt/mTOR pathway. Inhibition of mTOR or Akt augmented AG-4 induced apoptosis and autophagy signifying its crucial role in its mechanism of action. Thus, these findings prove the dual ability of AG-4 to induce apoptosis and autophagy which provide a new perspective to it as a potential molecule targeting PCD for future cancer therapeutics.

  1. Sulforaphane-induced autophagy flux prevents prion protein-mediated neurotoxicity through AMPK pathway.

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    Lee, J-H; Jeong, J-K; Park, S-Y

    2014-10-10

    Prion diseases are neurodegenerative and infectious disorders that involve accumulation of misfolded scrapie prion protein, and which are characterized by spongiform degeneration. Autophagy, a major homeostatic process responsible for the degradation of cytoplasmic components, has garnered attention as the potential target for neurodegenerative diseases such as prion disease. We focused on protective effects of sulforaphane found in cruciferous vegetables on prion-mediated neurotoxicity and the mechanism of sulforaphane related to autophagy. In human neuroblastoma cells, sulforaphane protected prion protein (PrP) (106-126)-mediated neurotoxicity and increased autophagy flux marker microtubule-associated protein 1 light chain 3-II protein levels, following a decrease of p62 protein level. Pharmacological and genetical inhibition of autophagy by 3MA, wortmannin and knockdown of autophagy-related 5 (ATG5) led to block the effect of sulforaphane against PrP (106-126)-induced neurotoxicity. Furthermore we demonstrated that both sulforaphane-induced autophagy and protective effect of sulforaphane against PrP (106-126)-induced neurotoxicity are dependent on the AMP-activated protein kinase (AMPK) signaling. The present results indicated that sulforaphane of cruciferous vegetables enhanced autophagy flux led to the protection effects against prion-mediated neurotoxicity, which was regulated by AMPK signaling pathways in human neuron cells. Our data also suggest that sulforaphane has a potential value as a therapeutic tool in neurodegenerative disease including prion diseases. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  2. ProbioticBacillus amyloliquefaciensSC06 Induces Autophagy to Protect against Pathogens in Macrophages.

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    Wu, Yanping; Wang, Yang; Zou, Hai; Wang, Baikui; Sun, Qiming; Fu, Aikun; Wang, Yuanyuan; Wang, Yibing; Xu, Xiaogang; Li, Weifen

    2017-01-01

    Probiotics are increasingly applied in popularity in both humans and animals. Decades of research has revealed their beneficial effects, including the immune modulation in intestinal pathogens inhibition. Autophagy-a cellular process that involves the delivery of cytoplasmic proteins and organelles to the lysosome for degradation and recirculation-is essential to protect cells against bacterial pathogens. However, the mechanism of probiotics-mediated autophagy and its role in the elimination of pathogens are still unknown. Here, we evaluated Bacillus amyloliquefaciens SC06 (Ba)-induced autophagy and its antibacterial activity against Escherichia coli ( E. coli ) in murine macrophage cell line RAW264.7 cells. Western blotting and confocal laser scanning analysis showed that Ba activated autophagy in a dose- and time-dependent manner. Ba-induced autophagy was found to play a role in the elimination of intracellular bacteria when RAW264.7 cells were challenged with E. coli . Ba induced autophagy by increasing the expression of Beclin1 and Atg5-Atg12-Atg16 complex, but not the AKT/mTOR signaling pathway. Moreover, Ba pretreatment attenuated the activation of JNK in RAW264.7 cells during E. coli infection, further indicating a protective role for probiotics via modulating macrophage immunity. The above findings highlight a novel mechanism underlying the antibacterial activity of probiotics. This study enriches the current knowledge on probiotics-mediated autophagy, and provides a new perspective on the prevention of bacterial infection in intestine, which further the application of probiotics in food products.

  3. Rapamycin regulates autophagy and cell adhesion in induced pluripotent stem cells

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    Areechun Sotthibundhu

    2016-11-01

    Full Text Available Abstract Background Cellular reprogramming is a stressful process, which requires cells to engulf somatic features and produce and maintain stemness machineries. Autophagy is a process to degrade unwanted proteins and is required for the derivation of induced pluripotent stem cells (iPSCs. However, the role of autophagy during iPSC maintenance remains undefined. Methods Human iPSCs were investigated by microscopy, immunofluorescence, and immunoblotting to detect autophagy machinery. Cells were treated with rapamycin to activate autophagy and with bafilomycin to block autophagy during iPSC maintenance. High concentrations of rapamycin treatment unexpectedly resulted in spontaneous formation of round floating spheres of uniform size, which were analyzed for differentiation into three germ layers. Mass spectrometry was deployed to reveal altered protein expression and pathways associated with rapamycin treatment. Results We demonstrate that human iPSCs express high basal levels of autophagy, including key components of APMKα, ULK1/2, BECLIN-1, ATG13, ATG101, ATG12, ATG3, ATG5, and LC3B. Block of autophagy by bafilomycin induces iPSC death and rapamycin attenuates the bafilomycin effect. Rapamycin treatment upregulates autophagy in iPSCs in a dose/time-dependent manner. High concentration of rapamycin reduces NANOG expression and induces spontaneous formation of round and uniformly sized embryoid bodies (EBs with accelerated differentiation into three germ layers. Mass spectrometry analysis identifies actin cytoskeleton and adherens junctions as the major targets of rapamycin in mediating iPSC detachment and differentiation. Conclusions High levels of basal autophagy activity are present during iPSC derivation and maintenance. Rapamycin alters expression of actin cytoskeleton and adherens junctions, induces uniform EB formation, and accelerates differentiation. IPSCs are sensitive to enzyme dissociation and require a lengthy differentiation time

  4. Galectin-1-Induced Autophagy Facilitates Cisplatin Resistance of Hepatocellular Carcinoma.

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    Yu-Chi Su

    Full Text Available Hepatocellular carcinoma (HCC is one of the most common cancers in Taiwan. Although chemotherapy is the primary treatment for HCC patients, drug resistance often leads to clinical failure. Galectin-1 is a beta-galactoside binding lectin which is up-regulated in HCC patients and promotes tumor growth by mediating cancer cell adhesion, migration and proliferation, but its role in chemoresistance of HCC is poorly understood. In this study we found that galectin-1 is able to lead to chemoresistance against cisplatin treatment, and subsequent inhibition has reversed the effect of cell death in HCC cells. Moreover, galectin-1 was found to induce autophagic flux in HCC cells. Inhibition of autophagy by inhibitors or knockdown of Atg5 cancels galectin-1-induced cisplatin resistance in HCC cells. Increase of mitophagy triggered by galectin-1 was found to reduce the mitochondrial potential loss and apoptosis induced by cisplatin treatment. Finally, using an in situ hepatoma mouse model, we clearly demonstrated that inhibition of galectin-1 by thiodigalactoside could significantly augment the anti-HCC effect of cisplatin. Taken together, our findings offer a new insight into the chemoresistance galectin-1 causes against cisplatin treatment, and points to a potential approach to improve the efficacy of cisplatin in the treatment of HCC patients.

  5. Curcumin Induces Autophagy, Apoptosis, and Cell Cycle Arrest in Human Pancreatic Cancer Cells

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    Yaping Zhu

    2017-01-01

    Full Text Available Objective. Curcumin is an active extract from turmeric. The aim of this study was to identify the underlying mechanism of curcumin on PCa cells and the role of autophagy in this process. Methods. The inhibitory effect of curcumin on the growth of PANC1 and BxPC3 cell lines was detected by CCK-8 assay. Cell cycle distribution and apoptosis were tested by flow cytometry. Autophagosomes were tested by cell immunofluorescence assay. The protein expression was detected by Western blot. The correlation between LC3II/Bax and cell viability was analyzed. Results. Curcumin inhibited the cell proliferation in a dose- and time-dependent manner. Curcumin could induce cell cycle arrest at G2/M phase and apoptosis of PCa cells. The autophagosomes were detected in the dosing groups. Protein expression of Bax and LC3II was upregulated, while Bcl2 was downregulated in the high dosing groups of curcumin. There was a significant negative correlation between LC3II/Bax and cell viability. Conclusions. Autophagy could be triggered by curcumin in the treatment of PCa. Apoptosis and cell cycle arrest also participated in this process. These findings imply that curcumin is a multitargeted agent for PCa cells. In addition, autophagic cell death may predominate in the high concentration groups of curcumin.

  6. Propofol protects against oxidative-stress-induced COS-7 cell apoptosis by inducing autophagy.

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    Yoon, Ji-Young; Baek, Chul-Woo; Kim, Eun-Jung; Park, Bong-Soo; Yu, Su-Bin; Yoon, Ji-Uk; Kim, Eok-Nyun

    2017-03-01

    In oxidative stress, reactive oxygen species (ROS) production contributes to cellular dysfunction and initiates the apoptotic cascade. Autophagy is considered the mechanism that decreases ROS concentration and oxidative damage. Propofol shows antioxidant properties, but the mechanisms underlying the effect of propofol preconditioning (PPC) on oxidative injury remain unclear. Therefore, we investigated whether PPC protects against cell damage from hydrogen peroxide (H 2 O 2 )-induced oxidative stress and influences cellular autophagy. COS-7 cells were randomly divided into the following groups: control, cells were incubated in normoxia (5% CO 2 , 21% O 2 , and 74% N 2 ) for 24 h without propofol; H 2 O 2 , cells were exposed to H 2 O 2 (400 µM) for 2 h; PPC + H 2 O 2 , cells pretreated with propofol were exposed to H 2 O 2 ; and 3-methyladenine (3-MA) + PPC + H 2 O 2 , cells pretreated with 3-MA (1 mM) for 1 h and propofol were exposed to H 2 O 2 . Cell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide thiazolyl blue (MTT) reduction. Apoptosis was determined using Hoechst 33342 staining and fluorescence microscopy. The relationship between PPC and autophagy was detected using western blot analysis. Cell viability decreased more significantly in the H 2 O 2 group than in the control group, but it was improved by PPC (100 µM). Pretreatment with propofol effectively decreased H 2 O 2 -induced COS-7 cell apoptosis. However, pretreatment with 3-MA inhibited the protective effect of propofol during apoptosis. Western blot analysis showed that the level of autophagy-related proteins was higher in the PPC + H 2 O 2 group than that in the H 2 O 2 group. PPC has a protective effect on H 2 O 2 -induced COS-7 cell apoptosis, which is mediated by autophagy activation.

  7. DRAM1 Protects Neuroblastoma Cells from Oxygen-Glucose Deprivation/Reperfusion-Induced Injury via Autophagy

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    Mengqiang Yu

    2014-10-01

    Full Text Available DNA damage-regulated autophagy modulator protein 1 (DRAM1, a multi-pass membrane lysosomal protein, is reportedly a tumor protein p53 (TP53 target gene involved in autophagy. During cerebral ischemia/reperfusion (I/R injury, DRAM1 protein expression is increased, and autophagy is activated. However, the functional significance of DRAM1 and the relationship between DRAM1 and autophagy in brain I/R remains uncertain. The aim of this study is to investigate whether DRAM1 mediates autophagy activation in cerebral I/R injury and to explore its possible effects and mechanisms. We adopt the oxygen-glucose deprivation and reperfusion (OGD/R Neuro-2a cell model to mimic cerebral I/R conditions in vitro, and RNA interference is used to knock down DRAM1 expression in this model. Cell viability assay is performed using the LIVE/DEAD viability/cytotoxicity kit. Cell phenotypic changes are analyzed through Western blot assays. Autophagy flux is monitored through the tandem red fluorescent protein–Green fluorescent protein–microtubule associated protein 1 light chain 3 (RFP–GFP–LC3 construct. The expression levels of DRAM1 and microtubule associated protein 1 light chain 3II/I (LC3II/I are strongly up-regulated in Neuro-2a cells after OGD/R treatment and peaked at the 12 h reperfusion time point. The autophagy-specific inhibitor 3-Methyladenine (3-MA inhibits the expression of DRAM1 and LC3II/I and exacerbates OGD/R-induced cell injury. Furthermore, DRAM1 knockdown aggravates OGD/R-induced cell injury and significantly blocks autophagy through decreasing autophagosome-lysosome fusion. In conclusion, our data demonstrate that DRAM1 knockdown in Neuro-2a cells inhibits autophagy by blocking autophagosome-lysosome fusion and exacerbated OGD/R-induced cell injury. Thus, DRAM1 might constitute a new therapeutic target for I/R diseases.

  8. Orexin A induces autophagy in HCT-116 human colon cancer cells through the ERK signaling pathway.

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    Wen, Jing; Zhao, Yuyan; Guo, Lei

    2016-01-01

    Orexins are a class of peptides which have a potent influence on a broad variety of cancer cells. Autophagy is closely associated with tumors; however, its function is not yet completely understood. In this study, we aimed to determine whether orexin A induces autophagy in HCT‑116 human colon cancer cells and to elucidate the molecular mechanisms involved. For this purpose, HCT‑116 cells were treated with orexin A, and cell viability was then measured by MTT assay, and apoptosis was determined by flow cytometry. The expression levels of autophagy‑related proteins were measured by western blot analysis. Quantitative analysis of autophagy following acridine orange (AO) staining was performed using fluorescence microscopy, and cellular morphology was observed under a transmission electron microscope. In addition, the HCT‑116 cells were treated with the extracellular signal‑regulated kinase (ERK) inhibitor, U0126, or the autophagy inhibitor, chloroquine, in combination with orexin A in order to examine the activation of ERK. We found that orexin A significantly inhibited the viability of the HCT‑116 cells. Both autophagy and apoptosis were activated during the orexin A‑induced death of HCT‑116 cells. When the HCT‑116 cells were treated with orexin A for 24 h, an accumulation of punctate microtubule-associated protein-1 light chain 3 (LC3) and an increase in LC3‑Ⅱ protein levels were also detected, indicating the activation of autophagy. Moreover, orexin A upregulated ERK phosphorylation; however, U0126 or chloroquine abrogated ERK phosphorylation and decreased autophagy, compared to treatment with orexin A alone. Therefore, our findings demonstratedm that orexin A induced autophagy through the ERK pathway in HCT‑116 human colon cancer cells. The inhibition of autophagy may thus prove to be an effective strategy for enhancing the antitumor potential of orexin A as a treatment for colon cancer.

  9. Stimulation of autophagy prevents amyloid-β peptide-induced neuritic degeneration in PC12 cells.

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    Yang, Yi; Chen, Sicong; Zhang, Jiafeng; Li, Chentan; Sun, Yonghong; Zhang, Lihui; Zheng, Xiaoxiang

    2014-01-01

    Autophagy is a lysosomal degradative process essential for neuronal homeostasis, whereas autophagic failure has been linked to accumulating neurodegenerative disorders. However, the precise role of autophagy in axonal and dendritic degeneration in Alzheimer's disease (AD) remains unclear. In this study, we aim to investigate the precise effect of autophagy in amyloid-β peptide (Aβ)25-35-mediated neurite degeneration. Aβ35-25, the non-neurotoxic reverse sequence analogue of Aβ25-35, was used as a negative control. Our results showed that Aβ25-35 dose-dependently suppressed PC12 proliferation and induced autophagy induction in neurites (axons and dendrites). A high proportion of autophagic structures in PC12 neurites were autolysosomes after 24 h of Aβ25-35 treatment. Autophagy inhibition by 3-methyladenine (3MA), LY294002, and chloroquine (CQ) could not relieve the Aβ25-35-induced neurite degeneration, while administration of autophagy stimulator rapamycin or AR-12 efficiently suppressed neurite degeneration. Autophagosomes colocalized with fragmented mitochondria after Aβ25-35 treatment. Similar results were obtained using in vitro cultured superior cervical ganglion neurons. These findings demonstrate that autophagy stimulation may prevent neuritic degeneration following Aβ25-35 treatment. Upregulation of autophagic activity may provide a valuable approach for the treatment of axonal and dendritic dystrophy in AD patients.

  10. Interferon-regulatory factor-1 (IRF1) regulates bevacizumab induced autophagy

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    Henry, Verlene; Tiao, Ningyi; de Groot, John F.

    2015-01-01

    Purpose Antiangiogenic therapy is commonly being used for the treatment of glioblastoma. However, the benefits of angiogenesis inhibitors are typically transient and resistance often develops. Determining the mechanism of treatment failure of the VEGF monoclonal antibody bevacizumab for malignant glioma would provide insight into approaches to overcome therapeutic resistance. Experimental Design In this study, we evaluated the effects of bevacizumab on the autophagy of glioma cells and determined target genes involving in the regulation of bevacizumab-induced autophagy. Results We demonstrated that bevacizumab treatment increased expression of autophagy markers and autophagosome formation in cell culture experiments as well as in in vivo studies. Gene expression profile analysis performed on murine xenograft models of glioblastoma showed increased transcriptional levels of STAT1/IRF1 signaling in bevacizumab resistant tumors compared to control tumors. In vitro experiments showed that bevacizumab treatment increased IRF1 expression in a dose and time dependent manner, which was coincident with bevacizumab-mediated autophagy. Down regulation of IRF1 by shRNA blocked autophagy and increased AIF-dependent apoptosis in bevacizumab-treated glioma cells. Consistently, IRF1 depletion increased the efficacy of anti-VEGF therapy in a glioma xenograft model, which was due to less bevacizumab-promoted autophagy and increased apoptosis in tumors with down-regulated IRF1. Conclusions These data suggest that IRF1 may regulate bevacizumab-induced autophagy, and may be one important mediator of glioblastoma resistant to bevacizumab. PMID:26362401

  11. FGFR antagonist induces protective autophagy in FGFR1-amplified breast cancer cell

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    Chen, Yi [The School of Biomedical Sciences, Chengdu Medical College, Chengdu 610083 (China); Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Chengdu (China); Xie, Xiaoyan; Li, Xinyi; Wang, Peiqi [State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University (China); Jing, Qian; Yue, Jiaqi; Liu, Yang [The School of Biomedical Sciences, Chengdu Medical College, Chengdu 610083 (China); Cheng, Zhong [Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, Chengdu (China); Li, Jingyi, E-mail: li--jingyi@hotmail.com [The School of Biomedical Sciences, Chengdu Medical College, Chengdu 610083 (China); Song, Haixing [The School of Biomedical Sciences, Chengdu Medical College, Chengdu 610083 (China); Li, Guoyu, E-mail: liguoyulisa@163.com [School of Pharmacy, Shihezi University, Shihezi 832003 (China); Liu, Rui, E-mail: liurui_scu@hotmail.com [State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University (China); Wang, Jinhui [School of Pharmacy, Shihezi University, Shihezi 832003 (China)

    2016-05-20

    Breast cancer, representing approximately 30% of all gynecological cancer cases diagnosed yearly, is a leading cause of cancer-related mortality for women. Amplification of FGFR1 is frequently observed in breast cancers and is associated with poor prognosis. Though FGFRs have long been considered as anti-cancer drug targets, and a cluster of FGFR antagonists are currently under clinical trials, the precise cellular responses under the treatment of FGFR antagonists remains unclear. Here, we show that PD166866, an FGFR1-selective inhibitor, inhibits proliferation and triggers anoikis in FGFR1-amplified breast cancer cell lines. Notably, we demonstrate that PD166866 induces autophagy in FGFR1-amplified breast cancer cell lines, while blockage of autophagy by Atg5 knockdown further enhances the anti-proliferative activities of PD166866. Moreover, mechanistic study reveals that PD166866 induces autophagy through repressing Akt/mTOR signaling pathway. Together, the present study provides new insights into the molecular mechanisms underlying the anti-tumor activities of FGFR antagonists, and may further assist the FGFRs-based drug discovery. -- Highlights: •FGFR1 antagonist inhibits cell viability in FGFR1-amplified breast cancer cells. •FGFR1 antagonist induces autophagy in FGFR1-amplified breast cancer cells. •FGFR1 antagonist-induced autophagy is protective. •FGFR1 antagonist induces autophagy by inhibiting Akt/mTOR pathway.

  12. FGFR antagonist induces protective autophagy in FGFR1-amplified breast cancer cell

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    Chen, Yi; Xie, Xiaoyan; Li, Xinyi; Wang, Peiqi; Jing, Qian; Yue, Jiaqi; Liu, Yang; Cheng, Zhong; Li, Jingyi; Song, Haixing; Li, Guoyu; Liu, Rui; Wang, Jinhui

    2016-01-01

    Breast cancer, representing approximately 30% of all gynecological cancer cases diagnosed yearly, is a leading cause of cancer-related mortality for women. Amplification of FGFR1 is frequently observed in breast cancers and is associated with poor prognosis. Though FGFRs have long been considered as anti-cancer drug targets, and a cluster of FGFR antagonists are currently under clinical trials, the precise cellular responses under the treatment of FGFR antagonists remains unclear. Here, we show that PD166866, an FGFR1-selective inhibitor, inhibits proliferation and triggers anoikis in FGFR1-amplified breast cancer cell lines. Notably, we demonstrate that PD166866 induces autophagy in FGFR1-amplified breast cancer cell lines, while blockage of autophagy by Atg5 knockdown further enhances the anti-proliferative activities of PD166866. Moreover, mechanistic study reveals that PD166866 induces autophagy through repressing Akt/mTOR signaling pathway. Together, the present study provides new insights into the molecular mechanisms underlying the anti-tumor activities of FGFR antagonists, and may further assist the FGFRs-based drug discovery. -- Highlights: •FGFR1 antagonist inhibits cell viability in FGFR1-amplified breast cancer cells. •FGFR1 antagonist induces autophagy in FGFR1-amplified breast cancer cells. •FGFR1 antagonist-induced autophagy is protective. •FGFR1 antagonist induces autophagy by inhibiting Akt/mTOR pathway.

  13. Autophagy regulates chlorpyrifos-induced apoptosis in SH-SY5Y cells

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    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

  14. Autophagy Protects against CYP2E1/Chronic Ethanol-Induced Hepatotoxicity

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    Yongke Lu

    2015-10-01

    Full Text Available Autophagy is an intracellular pathway by which lysosomes degrade and recycle long-lived proteins and cellular organelles. The effects of ethanol on autophagy are complex but recent studies have shown that autophagy serves a protective function against ethanol-induced liver injury. Autophagy was found to also be protective against CYP2E1-dependent toxicity in vitro in HepG2 cells which express CYP2E1 and in vivo in an acute alcohol/CYPE1-dependent liver injury model. The goal of the current report was to extend the previous in vitro and acute in vivo experiments to a chronic ethanol model to evaluate whether autophagy is also protective against CYP2E1-dependent liver injury in a chronic ethanol-fed mouse model. Wild type (WT, CYP2E1 knockout (KO or CYP2E1 humanized transgenic knockin (KI, mice were fed an ethanol liquid diet or control dextrose diet for four weeks. In the last week, some mice received either saline or 3-methyladenine (3-MA, an inhibitor of autophagy, or rapamycin, which stimulates autophagy. Inhibition of autophagy by 3-MA potentiated the ethanol-induced increases in serum transaminase and triglyceride levels in the WT and KI mice but not KO mice, while rapamycin prevented the ethanol liver injury. Treatment with 3-MA enhanced the ethanol-induced fat accumulation in WT mice and caused necrosis in the KI mice; little or no effect was found in the ethanol-fed KO mice or any of the dextrose-fed mice. 3-MA treatment further lowered the ethanol-decrease in hepatic GSH levels and further increased formation of TBARS in WT and KI mice, whereas rapamycin blunted these effects of ethanol. Neither 3-MA nor rapamycin treatment affected CYP2E1 catalytic activity or content or the induction CYP2E1 by ethanol. The 3-MA treatment decreased levels of Beclin-1 and Atg 7 but increased levels of p62 in the ethanol-fed WT and KI mice whereas rapamycin had the opposite effects, validating inhibition and stimulation of autophagy, respectively. These

  15. Chromomycin A2 Induces Autophagy in Melanoma Cells

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    Guimarães, Larissa Alves; Jimenez, Paula Christine; Sousa, Thiciana da Silva; Freitas, Hozana Patrícia S.; Rocha, Danilo Damasceno; Wilke, Diego Veras; Martín, Jesús; Reyes, Fernando; Pessoa, Otília Deusdênia Loiola; Costa-Lotufo, Letícia Veras

    2014-01-01

    The present study highlights the biological effects of chromomycin A2 toward metastatic melanoma cells in culture. Besides chromomycin A2, chromomycin A3 and demethylchromomycin A2 were also identified from the extract derived from Streptomyces sp., recovered from Paracuru Beach, located in the northeast region of Brazil. The cytotoxic activity of chromomycin A2 was evaluated across a panel of human tumor cell lines, which found IC50 values in the nM-range for exposures of 48 and 72 h. MALME-3M, a metastatic melanoma cell line, showed the highest sensitivity to chromomycin A2 after 48h incubation, and was chosen as a model to investigate this potent cytotoxic effect. Treatment with chromomycin A2 at 30 nM reduced cell proliferation, but had no significant effect upon cell viability. Additionally, chromomycin A2 induced accumulation of cells in G0/G1 phase of the cell cycle, with consequent reduction of S and G2/M and unbalanced expression of cyclins. Chromomycin A2 treated cells depicted several cellular fragments resembling autophagosomes and increased expression of proteins LC3-A and LC3-B. Moreover, exposure to chromomycin A2 also induced the appearance of acidic vacuolar organelles in treated cells. These features combined are suggestive of the induction of autophagy promoted by chromomycin A2, a feature not previously described for chromomycins. PMID:25486109

  16. MiR-30-Regulated Autophagy Mediates Angiotensin II-Induced Myocardial Hypertrophy

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    Pan, Wei; Zhong, Yun; Cheng, Chuanfang; Liu, Benrong; Wang, Li; Li, Aiqun; Xiong, Longgen; Liu, Shiming

    2013-01-01

    Dysregulated autophagy may lead to the development of disease. Role of autophagy and the diagnostic potential of microRNAs that regulate the autophagy in cardiac hypertrophy have not been evaluated. A rat model of cardiac hypertrophy was established using transverse abdominal aortic constriction (operation group). Cardiomyocyte autophagy was enhanced in rats from the operation group, compared with those in the sham operation group. Moreover, the operation group showed up-regulation of beclin-1 (an autophagy-related gene), and down-regulation of miR-30 in cardiac tissue. The effects of inhibition and over-expression of the beclin-1 gene on the expression of hypertrophy-related genes and on autophagy were assessed. Angiotensin II-induced myocardial hypertrophy was found to be mediated by over-expression of the beclin-1 gene. A dual luciferase reporter assay confirmed that beclin-1 was a target gene of miR-30a. miR-30a induced alterations in beclin-1 gene expression and autophagy in cardiomyocytes. Treatment of cardiomyocytes with miR-30a mimic attenuated the Angiotensin II-induced up-regulation of hypertrophy-related genes and decreased in the cardiomyocyte surface area. Conversely, treatment with miR-30a inhibitor enhanced the up-regulation of hypertrophy-related genes and increased the surface area of cardiomyocytes induced by Angiotensin II. In addition, circulating miR-30 was elevated in patients with left ventricular hypertrophy, and circulating miR-30 was positively associated with left ventricular wall thickness. Collectively, these above-mentioned results suggest that Angiotensin II induces down-regulation of miR-30 in cardiomyocytes, which in turn promotes myocardial hypertrophy through excessive autophagy. Circulating miR-30 may be an important marker for the diagnosis of left ventricular hypertrophy. PMID:23326547

  17. Egr-1 regulates autophagy in cigarette smoke-induced chronic obstructive pulmonary disease.

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    Zhi-Hua Chen

    2008-10-01

    Full Text Available Chronic obstructive pulmonary disease (COPD is a progressive lung disease characterized by abnormal cellular responses to cigarette smoke, resulting in tissue destruction and airflow limitation. Autophagy is a degradative process involving lysosomal turnover of cellular components, though its role in human diseases remains unclear.Increased autophagy was observed in lung tissue from COPD patients, as indicated by electron microscopic analysis, as well as by increased activation of autophagic proteins (microtubule-associated protein-1 light chain-3B, LC3B, Atg4, Atg5/12, Atg7. Cigarette smoke extract (CSE is an established model for studying the effects of cigarette smoke exposure in vitro. In human pulmonary epithelial cells, exposure to CSE or histone deacetylase (HDAC inhibitor rapidly induced autophagy. CSE decreased HDAC activity, resulting in increased binding of early growth response-1 (Egr-1 and E2F factors to the autophagy gene LC3B promoter, and increased LC3B expression. Knockdown of E2F-4 or Egr-1 inhibited CSE-induced LC3B expression. Knockdown of Egr-1 also inhibited the expression of Atg4B, a critical factor for LC3B conversion. Inhibition of autophagy by LC3B-knockdown protected epithelial cells from CSE-induced apoptosis. Egr-1(-/- mice, which displayed basal airspace enlargement, resisted cigarette-smoke induced autophagy, apoptosis, and emphysema.We demonstrate a critical role for Egr-1 in promoting autophagy and apoptosis in response to cigarette smoke exposure in vitro and in vivo. The induction of autophagy at early stages of COPD progression suggests novel therapeutic targets for the treatment of cigarette smoke induced lung injury.

  18. Cocaine induces astrocytosis through ER stress-mediated activation of autophagy

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    Periyasamy, Palsamy; Guo, Ming-Lei; Buch, Shilpa

    2016-01-01

    ABSTRACT Cocaine is known to induce inflammation, thereby contributing in part, to the pathogenesis of neurodegeneration. A recent study from our lab has revealed a link between macroautophagy/autophagy and microglial activation. The current study was aimed at investigating whether cocaine could also mediate activation of astrocytes and, whether this process involved induction of autophagy. Our findings demonstrated that cocaine mediated the activation of astrocytes by altering the levels of autophagy markers, such as BECN1, ATG5, MAP1LC3B-II, and SQSTM1 in both human A172 astrocytoma cells and primary human astrocytes. Furthermore, cocaine treatment resulted in increased formation of endogenous MAP1LC3B puncta in human astrocytes. Additionally, astrocytes transfected with the GFP-MAP1LC3B plasmid also demonstrated cocaine-mediated upregulation of the green fluorescent MAP1LC3B puncta. Cocaine-mediated induction of autophagy involved upstream activation of ER stress proteins such as EIF2AK3, ERN1, ATF6 since blockage of autophagy using either pharmacological or gene-silencing approaches, had no effect on cocaine-mediated induction of ER stress. Using both pharmacological and gene-silencing approaches to block either ER stress or autophagy, our findings demonstrated that cocaine-induced activation of astrocytes (measured by increased levels of GFAP) involved sequential activation of ER stress and autophagy. Cocaine-mediated-increased upregulation of GFAP correlated with increased expression of proinflammatory mediators such as TNF, IL1B, and IL6. In conclusion, these findings reveal an association between ER stress-mediated autophagy and astrogliosis in cocaine-treated astrocytes. Intervention of ER stress and/or autophagy signaling would thus be promising therapeutic targets for abrogating cocaine-mediated neuroinflammation. PMID:27337297

  19. Cocaine induces astrocytosis through ER stress-mediated activation of autophagy.

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    Periyasamy, Palsamy; Guo, Ming-Lei; Buch, Shilpa

    2016-08-02

    Cocaine is known to induce inflammation, thereby contributing in part, to the pathogenesis of neurodegeneration. A recent study from our lab has revealed a link between macroautophagy/autophagy and microglial activation. The current study was aimed at investigating whether cocaine could also mediate activation of astrocytes and, whether this process involved induction of autophagy. Our findings demonstrated that cocaine mediated the activation of astrocytes by altering the levels of autophagy markers, such as BECN1, ATG5, MAP1LC3B-II, and SQSTM1 in both human A172 astrocytoma cells and primary human astrocytes. Furthermore, cocaine treatment resulted in increased formation of endogenous MAP1LC3B puncta in human astrocytes. Additionally, astrocytes transfected with the GFP-MAP1LC3B plasmid also demonstrated cocaine-mediated upregulation of the green fluorescent MAP1LC3B puncta. Cocaine-mediated induction of autophagy involved upstream activation of ER stress proteins such as EIF2AK3, ERN1, ATF6 since blockage of autophagy using either pharmacological or gene-silencing approaches, had no effect on cocaine-mediated induction of ER stress. Using both pharmacological and gene-silencing approaches to block either ER stress or autophagy, our findings demonstrated that cocaine-induced activation of astrocytes (measured by increased levels of GFAP) involved sequential activation of ER stress and autophagy. Cocaine-mediated-increased upregulation of GFAP correlated with increased expression of proinflammatory mediators such as TNF, IL1B, and IL6. In conclusion, these findings reveal an association between ER stress-mediated autophagy and astrogliosis in cocaine-treated astrocytes. Intervention of ER stress and/or autophagy signaling would thus be promising therapeutic targets for abrogating cocaine-mediated neuroinflammation.

  20. Isoflavones Induce BEX2-Dependent Autophagy to Prevent ATR-Induced Neurotoxicity in SH-SY5Y Cells

    Directory of Open Access Journals (Sweden)

    Peng Li

    2017-10-01

    Full Text Available Background/Aims: Atrazine (ATR is a broad-spectrum herbicide in wide use around the world. However, ATR is neurotoxic and can cause cell death in dopaminergic neurons, leading to neurodegenerative disorders. Autophagy is the basic cellular catabolic process involving the degradation of proteins and damaged organelles. Studies have shown that certain plant compounds can induce autophagy and prevent neuronal cell death. This prompted us to investigate plant compounds that might reduce the neurotoxic effects of ATR. Methods: By CCK-8 and flow cytometry, we tested the ability of five candidate compounds—isoflavones, resveratrol, quercetin, curcumin, and green tea polyphenols—to protect cells from ATR. Changes in the expression of tyrosine hydroxylase (TH and brain-expressed X-linked 2 (BEX2, autophagy-related proteins and key factors in mTOR signaling, were detected by Western blotting. Results: Isoflavones had the strongest activity against ATR-induced neuronal apoptosis. ATR reduced the expression of TH and BEX2, whereas isoflavones increased TH and BEX2 expression. In addition, ATR inhibited autophagy, whereas isoflavones induced autophagy through the accumulation of LC3-II and decreased expression of p62; this effect was abolished by 3-methyladenine (3-MA. Furthermore, BEX2 siRNA abolished isoflavone-mediated autophagy and neuroprotection in vitro. Conclusion: Isoflavones activate BEX2-dependent autophagy, protecting against ATR-induced neuronal apoptosis.

  1. SPBP Is a Sulforaphane Induced Transcriptional Coactivator of NRF2 Regulating Expression of the Autophagy Receptor p62/SQSTM1

    Science.gov (United States)

    Darvekar, Sagar Ramesh; Elvenes, Julianne; Brenne, Hanne Britt; Johansen, Terje; Sjøttem, Eva

    2014-01-01

    Organisms exposed to oxidative stress respond by orchestrating a stress response to prevent further damage. Intracellular levels of antioxidant agents increase, and damaged components are removed by autophagy induction. The KEAP1-NRF2 signaling pathway is the main pathway responsible for cell defense against oxidative stress and for maintaining the cellular redox balance at physiological levels. Sulforaphane, an isothiocyanate derived from cruciferous vegetables, is a potent inducer of KEAP1-NRF2 signaling and antioxidant response element driven gene expression. In this study, we show that sulforaphane enhances the expression of the transcriptional coregulator SPBP. The expression curve peaks 6–8 hours post stimulation, and parallels the sulforaphane-induced expression of NRF2 and the autophagy receptor protein p62/SQSTM1. Reporter gene assays show that SPBP stimulates the expression of p62/SQSTM1 via ARE elements in the promoter region, and siRNA mediated knock down of SPBP significantly decreases the expression of p62/SQSTM1 and the formation of p62/SQSTM1 bodies in HeLa cells. Furthermore, SPBP siRNA reduces the sulforaphane induced expression of NRF2, and the expression of the autophagy marker protein LC3B. Both these proteins contain ARE-like elements in their promoter regions. Over-expressed SPBP and NRF2 acts synergistically on the p62/SQSTM1 promoter and colocalize in nuclear speckles in HeLa cells. Collectively, these results suggest that SPBP is a coactivator of NRF2, and hence may be important for securing enhanced and sustained expression of NRF2 induced genes such as proteins involved in selective autophagy. PMID:24416372

  2. SPBP is a sulforaphane induced transcriptional coactivator of NRF2 regulating expression of the autophagy receptor p62/SQSTM1.

    Directory of Open Access Journals (Sweden)

    Sagar Ramesh Darvekar

    Full Text Available Organisms exposed to oxidative stress respond by orchestrating a stress response to prevent further damage. Intracellular levels of antioxidant agents increase, and damaged components are removed by autophagy induction. The KEAP1-NRF2 signaling pathway is the main pathway responsible for cell defense against oxidative stress and for maintaining the cellular redox balance at physiological levels. Sulforaphane, an isothiocyanate derived from cruciferous vegetables, is a potent inducer of KEAP1-NRF2 signaling and antioxidant response element driven gene expression. In this study, we show that sulforaphane enhances the expression of the transcriptional coregulator SPBP. The expression curve peaks 6-8 hours post stimulation, and parallels the sulforaphane-induced expression of NRF2 and the autophagy receptor protein p62/SQSTM1. Reporter gene assays show that SPBP stimulates the expression of p62/SQSTM1 via ARE elements in the promoter region, and siRNA mediated knock down of SPBP significantly decreases the expression of p62/SQSTM1 and the formation of p62/SQSTM1 bodies in HeLa cells. Furthermore, SPBP siRNA reduces the sulforaphane induced expression of NRF2, and the expression of the autophagy marker protein LC3B. Both these proteins contain ARE-like elements in their promoter regions. Over-expressed SPBP and NRF2 acts synergistically on the p62/SQSTM1 promoter and colocalize in nuclear speckles in HeLa cells. Collectively, these results suggest that SPBP is a coactivator of NRF2, and hence may be important for securing enhanced and sustained expression of NRF2 induced genes such as proteins involved in selective autophagy.

  3. Mycobacterium tuberculosis induces the miR-33 locus to reprogram autophagy and host lipid metabolism

    OpenAIRE

    Ouimet, Mireille; Koster, Stefan; Sakowski, Erik; Ramkhelawon, Bhama; van Solingen, Coen; Oldebeken, Scott; Karunakaran, Denuja; Celhay, Cynthia Portal; Sheedy, Frederick J.; Ray, Tathagat Dutta; Cecchini, Katharine; Zamore, Philip D; Rayner, Katey J; Marcel, Yves L; Philips, Jennifer A

    2016-01-01

    Mycobacterium tuberculosis (Mtb) survives within macrophages by evading delivery to the lysosome and promoting the accumulation of lipid bodies, which serve as a bacterial source of nutrients. Here we show that by inducing miR-33 and its passenger strand miR-33*, Mtb inhibits integrated pathways involved in autophagy, lysosomal function and fatty acid oxidation to support bacterial replication. Silencing of miR-33 and miR-33* by genetic or pharmacological means promotes autophagy flux through...

  4. [Ginsenoside Rh₂ induces apoptosis and autophagy of K562 cells by activating p38].

    Science.gov (United States)

    Liu, Xiao-Xia; Xia, Jing; Tang, Jia-Feng; Zhou, Ming-Hua; Chen, Di-Long; Liu, Ze-Hong

    2017-01-01

    To study the effect of ginseng saponin Rh₂ in inducing apoptosis of human leukemia K562 cells, and explore its mechanism from the aspect of autophagy pathway. CCK-8 assay was used to examine the growth inhibition of human leukemia cell lines K562 treated with ginsenoside Rh₂; flow cytometry (FCM) was used to detect cell apoptosis; Hoechst staining was used to observe the changes of cell morphological apoptosis; Acridine and MDC staining were used to detect the effects of the Rh₂ on autophagy; Western blot and RT-PCR were used to detect the expression levels of the proteins closely associated with autophagy and apoptosis. In order to study the effect of autophagy in proliferation and apoptosis, we used the autophagy inhibitor (3-MA).CCK-8 indicated that Rh₂ at low concentration could effectively inhibit the proliferation of leukemia cellsin dose- and time-dependent manners in K562 cells; FCM indicated that Rh₂ induced apoptosis; Hoechest staining showed that K562 cells had typical apoptotic morphological changes by treated Rh₂; Acridine and MDC staining showed that Rh₂ enhanced the green fluorescence and a large number of acidic autophagy vesicles were present; Western blot and RT-PCR results showed that Rh₂ increased the expression levels of Beclin-1, LC3A, LC3B, activated Caspase-3 and p-p38 in K562 cells; application of autophagy inhibitors(3-MA) could weaken the inhibition effect of Rh₂ on proliferation and induction effect on apoptosis in K562 cells. Ginsenoside Rh₂ inhibited the proliferation and induced apoptosis probably through activating p-p38, and inducing cell autophagy signaling pathway in K562 cells. Copyright© by the Chinese Pharmaceutical Association.

  5. Autophagy attenuates noise-induced hearing loss by reducing oxidative stress.

    Science.gov (United States)

    Yuan, Hu; Wang, Xianren; Hill, Kayla; Chen, Jun; Lemasters, John; Yang, Shi-Ming; Sha, Su-Hua

    2015-05-20

    Reactive oxygen species play a dual role in mediating both cell stress and defense pathways. Here, we used pharmacological manipulations and siRNA silencing to investigate the relationship between autophagy and oxidative stress under conditions of noise-induced temporary, permanent, and severe permanent auditory threshold shifts (temporary threshold shift [TTS], permanent threshold shift [PTS], and severe PTS [sPTS], respectively) in adult CBA/J mice. Levels of oxidative stress markers (4-hydroxynonenal [4-HNE] and 3-nitrotyrosine [3-NT]) increased in outer hair cells (OHCs) in a noise-dose-dependent manner, whereas levels of the autophagy marker microtubule-associated protein light chain 3 B (LC3B) were sharply elevated after TTS but rose only slightly in response to PTS and were unaltered by sPTS noise. Furthermore, green fluorescent protein (GFP) intensity increased in GFP-LC3 mice after TTS-noise exposure. Treatment with rapamycin, an autophagy activator, significantly increased LC3B expression, while diminishing 4-HNE and 3-NT levels, reducing noise-induced hair cell loss, and, subsequently, noise-induced hearing loss (NIHL). In contrast, treatment with either the autophagy inhibitor 3-methyladenine (3MA) or LC3B siRNA reduced LC3B expression, increased 3-NT and 4-HNE levels, and exacerbated TTS to PTS. This study demonstrates a relationship between oxidative stress and autophagy in OHCs and reveals that autophagy is an intrinsic cellular process that protects against NIHL by attenuating oxidative stress. The results suggest that the lower levels of oxidative stress incurred by TTS-noise exposure induce autophagy, which promotes OHC survival. However, excessive oxidative stress under sPTS-noise conditions overwhelms the beneficial potential of autophagy in OHCs and leads to OHC death and NIHL.

  6. ARSENITE-INDUCED AUTOPHAGY IS ASSOCIATED WITH PROTEOTOXICITY IN HUMAN LYMPHOBLASTOID CELLS

    OpenAIRE

    Bolt, Alicia M.; Zhao, Fei; Pacheco, Samantha; Klimecki, Walter T.

    2012-01-01

    Epidemiological studies of arsenic-exposed populations have provided evidence that arsenic exposure in humans is associated with immunosuppression. Previously, we have reported that arsenite-induced toxicity is associated with the induction of autophagy in human lymphoblastoid cell lines (LCL). Autophagy is a cellular process that functions in the degradation of damaged cellular components, including protein aggregates formed by misfolded or damaged proteins. Accumulation of misfolded or dama...

  7. Autophagy and gap junctional intercellular communication inhibition are involved in cadmium-induced apoptosis in rat liver cells

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Hui [College of Veterinary Medicine, Yangzhou University, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009 (China); Zhuo, Liling [College of Life Science, Zaozhuang University, Zaozhuang, Shandong, 277160 (China); Han, Tao; Hu, Di; Yang, Xiaokang; Wang, Yi; Yuan, Yan; Gu, Jianhong; Bian, Jianchun; Liu, Xuezhong [College of Veterinary Medicine, Yangzhou University, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009 (China); Liu, Zongping, E-mail: liuzongping@yzu.edu.cn [College of Veterinary Medicine, Yangzhou University, and Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009 (China)

    2015-04-17

    Cadmium (Cd) is known to induce hepatotoxicity, yet the underlying mechanism of how this occurs is not fully understood. In this study, Cd-induced apoptosis was demonstrated in rat liver cells (BRL 3A) with apoptotic nuclear morphological changes and a decrease in cell index (CI) in a time- and concentration-dependent manner. The role of gap junctional intercellular communication (GJIC) and autophagy in Cd-induced apoptosis was investigated. Cd significantly induced GJIC inhibition as well as downregulation of connexin 43 (Cx43). The prototypical gap junction blocker carbenoxolone disodium (CBX) exacerbated the Cd-induced decrease in CI. Cd treatment was also found to cause autophagy, with an increase in mRNA expression of autophagy-related genes Atg-5, Atg-7, Beclin-1, and microtubule-associated protein light chain 3 (LC3) conversion from cytosolic LC3-I to membrane-bound LC3-II. The autophagic inducer rapamycin (RAP) prevented the Cd-induced CI decrease, while the autophagic inhibitor chloroquine (CQ) caused a further reduction in CI. In addition, CBX promoted Cd-induced autophagy, as well as changes in expression of Atg-5, Atg-7, Beclin-1 and LC3. CQ was found to block the Cd-induced decrease in Cx43 and GJIC inhibition, whereas RAP had opposite effect. These results demonstrate that autophagy plays a protective role during Cd-induced apoptosis in BRL 3A cells during 6 h of experiment, while autophagy exacerbates Cd-induced GJIC inhibition which has a negative effect on cellular fate. - Highlights: • GJIC and autophagy is crucial for biological processes. • Cd exposure causes GJIC inhibition and autophagy increase in BRL 3A cells. • Autophagy protects Cd induced BRL 3A cells apoptosis at an early stage. • Autophagy exacerbates Cd-induced GJIC inhibition. • GJIC plays an important role in autophagy induced cell death or survival.

  8. Glucocorticoids induce autophagy in rat bone marrow mesenchymal stem cells

    DEFF Research Database (Denmark)

    Wang, L.; Fan, J.; Lin, Y. S.

    2015-01-01

    and their responses to diverse stimuli, however, the role of autophagy in glucocorticoidinduced damage to bone marrow mesenchymal stem cells (BMSCs) remains unclear. The current study confirmed that glucocorticoid administration impaired the proliferation of BMSCs. Transmission electron microscopy...

  9. Formaldehyde exposure induces autophagy in testicular tissues of adult male rats.

    Science.gov (United States)

    Han, Shui-Ping; Zhou, Dang-Xia; Lin, Pu; Qin, Zhen; An, Lu; Zheng, Lie-Rui; Lei, Li

    2015-03-01

    Formaldehyde, a ubiquitous environmental pollutant, has long been suspected of causing adverse male reproductive effects. However, the molecular and cellular mechanisms underlying this phenomenon remain elusive. The overall aim of this study is to clarify the role of autophagy in male reproductive injuries induced by formaldehyde exposure, by which we can further understand the molecular mechanism of spermatogenesis and develop new targets for prevention and treatment of male infertility. In this study, electron microscopy, Western blot, and RT-PCR analysis were used to detect autophagy in testicular tissues. Moreover, testicular weights, histopathology, and morphometry were used to evaluate the reproductive injuries of formaldehyde exposure. We found that formaldehyde exposure-induced autophagy in testicular tissues was dose dependent. Increasing autophagosomes in spermatogenetic cells was observed by electron microscopy in formaldehyde exposure group. In addition, RT-PCR and Western blot analysis showed the transcription levels of the LC3-II, as well as the conversion from LC3-I to LC3-II, an indicator of autophagy, significantly increased in testicular tissue of formaldehyde exposure group in a dose dependent manner when compared with those in control group. Furthermore, the alterations of autophage were basically consistent with the changes in testicular weight and morphologic findings. In summary, formaldehyde exposure triggered autophagy, and autophagy may be a scathing factor responsible for male reproductive impairment induced by formaldehyde. © 2013 Wiley Periodicals, Inc.

  10. Effect of the cross-talk between autophagy and endoplasmic reticulum stress on Mn-induced alpha-synuclein oligomerization.

    Science.gov (United States)

    Liu, Chang; Yan, Dong-Ying; Tan, Xuan; Ma, Zhuo; Wang, Can; Deng, Yu; Liu, Wei; Yang, Tian-Yao; Xu, Zhao-Fa; Xu, Bin

    2018-03-01

    Overexposure to manganese (Mn) has been known to induce alpha-synuclein (α-Syn) oligomerization, which is degraded mainly depending on endoplasmic reticulum stress (ER stress) and autophagy pathways. However, little data reported the cross-talk between ER stress and autophagy on Mn-induced α-Syn oligomerization. To explore the relationship between ER stress and autophagy, we used 4-phenylbutyric acid (4-PBA, the ER stress inhibitor), rapamycin (Rap, autophagy activator) and 3-methyladenine (3-MA, autophagy inhibitor) in mice model of manganism. After 4 weeks of treatment with Mn, both ER stress and autophagy were activated. Exposed to Mn also resulted in α-Syn oligomerization and neuronal cell damage in the brain tissue of mice, which could be relieved by 4-PBA pretreatment. Moreover, when the ER stress was inhibited, the activation of autophagy was also inhibited. Rap pretreatment significantly activated autophagy and decreased α-Syn oligomers. However, 3-MA pretreatment inhibited autophagy resulting in increase of α-Syn oligomers, and compensatorily activated PERK signaling pathway. Our results also demonstrated that the inhibition of autophagy by 3-MA aggravated neuronal cell damage. The findings clearly demonstrated that the cross-talking between autophagy and ER stress might play an important role in the α-Syn oligomerization and neurotoxicity by Mn. © 2017 Wiley Periodicals, Inc.

  11. Autophagy relieves the function inhibition and apoptosis-promoting effects on osteoblast induced by glucocorticoid

    Science.gov (United States)

    Han, Yudi; Zhang, Lihai; Xing, Yaling; Zhang, Licheng; Chen, Xiaojuan; Tang, Peifu; Chen, Zhongbin

    2018-01-01

    Autophagy may be a major mechanism by which osteoblasts (OBs) protect against the negative effects of chronic glucocorticoid (GC) usage. OBs are closely associated with the remodeling that occurs in GC-induced osteoporosis (GIO). In osteocytes, in response to stress induced by GCs, several pathways are activated, including cell necrosis, apoptosis and autophagy. However, the role of autophagy in OBs following treatment with excess GCs has not been addressed. In the current study, confocal microscopy observation of green fluorescent protein-microtubule-associated protein 1 light chain 3β (LC3) punctuate, and western blotting for LC3II and Beclin 1 were performed for detection of autophagy in the MC3T3-E1 osteoblastic cell line. Flow cytometry and western blotting were used for the examination of apoptosis and expression of BAX apoptosis regulator (Bax)/apoptosis regulator Bcl-2 (Bcl-2). The expression of genes associated with osteoblastic function, runt-related transcription factor 2, α-1 type 1 collagen and osteocalcin, were measured by reverse transcription-quantitative polymerase chain reaction. The results indicated that autophagy was induced in OBs during dexamethasone (Dex) treatment in a dose-dependent manner. The level of autophagy did not continue to increase over time, but peaked at 48 h and then decreased gradually. Subsequently, flow cytometry was used to demonstrate that inhibition of autophagy induced apoptosis in OBs under Dex treatment, and was associated with the upregulation of Bax and the downregulation of Bcl-2 protein expression. Furthermore, the data suggested that the inhibition of autophagy also suppressed the expression of osteoblastic genes. By contrast, the stimulation of autophagy maintained the gene expression level under Dex treatment. The data revealed that autophagy is an important regulator of osteoblastic apoptosis through its interaction with Bax/Bcl-2, and maintains the osteoblastic function of MC3T3-E1 cells following GC

  12. SIRT1 inactivation induces inflammation through the dysregulation of autophagy in human THP-1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Takeda-Watanabe, Ai; Kitada, Munehiro; Kanasaki, Keizo [Diabetology and Endocrinology, Kanazawa Medical University, Kahoku-Gun, Ishikawa (Japan); Koya, Daisuke, E-mail: koya0516@kanazawa-med.ac.jp [Diabetology and Endocrinology, Kanazawa Medical University, Kahoku-Gun, Ishikawa (Japan)

    2012-10-12

    Highlights: Black-Right-Pointing-Pointer SIRT1 inactivation decreases autophagy in THP-1 cell. Black-Right-Pointing-Pointer Inhibition of autophagy induces inflammation. Black-Right-Pointing-Pointer SIRT1 inactivation induces inflammation through NF-{kappa}B activation. Black-Right-Pointing-Pointer The p62/Sqstm1 accumulation by impairment of autophagy is related to NF-{kappa}B activation. Black-Right-Pointing-Pointer SIRT1 inactivation is involved in the activation of mTOR and decreased AMPK activation. -- Abstract: Inflammation plays a crucial role in atherosclerosis. Monocytes/macrophages are some of the cells involved in the inflammatory process in atherogenesis. Autophagy exerts a protective effect against cellular stresses like inflammation, and it is regulated by nutrient-sensing pathways. The nutrient-sensing pathway includes SIRT1, a NAD{sup +}-dependent histone deacetylase, which is implicated in the regulation of a variety of cellular processes including inflammation and autophagy. The mechanism through which the dysfunction of SIRT1 contributes to the regulation of inflammation in relation to autophagy in monocytes/macrophages is unclear. In the present study, we demonstrate that treatment with 2-[(2-Hydroxynaphthalen-1-ylmethylene)amino]-N-(1-phenethyl)benzamide (Sirtinol), a chemical inhibitor of SIRT1, induces the overexpression of inflammation-related genes such as tumor necrosis factor (TNF)-{alpha} and interleukin (IL)-6 through nuclear factor (NF)-{kappa}B signaling activation, which is associated with autophagy dysfunction, as shown through p62/Sqstm1 accumulation and decreased expression of light chain (LC) 3 II in THP-1 cells. The autophagy inhibitor, 3-methyladenine, also induces inflammation-related NF-{kappa}B activation. In p62/Sqstm1 knockdown cells, Sirtinol-induced inflammation through NF-{kappa}B activation is blocked. In addition, inhibition of SIRT1 is involved in the activation of the mammalian target of rapamycin (mTOR) pathway and

  13. Roles of Autophagy Induced by Natural Compounds in Prostate Cancer

    Directory of Open Access Journals (Sweden)

    V. Naponelli

    2015-01-01

    Full Text Available Autophagy is a homeostatic mechanism through which intracellular organelles and proteins are degraded and recycled in response to increased metabolic demand or stress. Autophagy dysfunction is often associated with many diseases, including cancer. Because of its role in tumorigenesis, autophagy can represent a new therapeutic target for cancer treatment. Prostate cancer (PCa is one of the most common cancers in aged men. The evidence on alterations of autophagy related genes and/or protein levels in PCa cells suggests a potential implication of autophagy in PCa onset and progression. The use of natural compounds, characterized by low toxicity to normal tissue associated with specific anticancer effects at physiological levels in vivo, is receiving increasing attention for prevention and/or treatment of PCa. Understanding the mechanism of action of these compounds could be crucial for the development of new therapeutic or chemopreventive options. In this review we focus on the current evidence showing the capacity of natural compounds to exert their action through autophagy modulation in PCa cells.

  14. Curcumin induced autophagy anticancer effects on human lung adenocarcinoma cell line A549.

    Science.gov (United States)

    Liu, Furong; Gao, Song; Yang, Yuxuan; Zhao, Xiaodan; Fan, Yameng; Ma, Wenxia; Yang, Danrong; Yang, Aimin; Yu, Yan

    2017-09-01

    To investigate the anticancer effects of curcumin-induced autophagy and its effects on the human lung adenocarcinoma A549 cell line, inverted phase contrast microscopy was used to observe alterations to the cytomorphology of cells. An MTT assay was used to measure cell viability. Autophagy was detected using acridine orange (AO) staining and 3-methyladenine (3-MA) was used as an autophagy-specific inhibitor. Dose- and time-dependent A549 cell viability inhibition was observed following curcumin treatment. A dose-dependent increase in the red fluorescent structures in A549 cells was identified following curcumin treatment for 48 h through AO staining. In addition, the activation of autophagy was determined through changes in the number of autophagic vesicles (AVs; fluorescent particles) infected with monodansylcadaverine (MDC). The fluorescence intensity and density of AVs in the curcumin-treated groups were higher at 48 h compared with the control group. Finally, the MTT assay demonstrated that the survival rates of the curcumin-treated cells were increased when pretreated with 3-MA for 3 h, indicating that the inhibitory effect of curcumin on A549 cells is reduced following the inhibition of autophagy. Furthermore, AO and MDC staining confirmed that 3-MA does inhibit the induction of autophagy. Thus, it was hypothesized that the induction of autophagy is partially involved in the reduction of cell viability observed following curcumin treatment. The anticancer effects of curcumin on A549 cells can be reduced using autophagy inhibitors. This suggests a possible cancer therapeutic application of curcumin through the activation of autophagy. These findings have improved the understanding of the mechanism underlying the anticancer property of curcumin.

  15. Tetrandrine induces lipid accumulation through blockade of autophagy in a hepatic stellate cell line

    Energy Technology Data Exchange (ETDEWEB)

    Miyamae, Yusaku, E-mail: ymiyamae@lif.kyoto-u.ac.jp [Graduate School of Biostudies, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Nishito, Yukina; Nakai, Naomi [Graduate School of Biostudies, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Nagumo, Yoko; Usui, Takeo [Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai, Tsukuba, Ibaraki 305-8572 (Japan); Masuda, Seiji; Kambe, Taiho [Graduate School of Biostudies, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Nagao, Masaya, E-mail: mnagao@kais.kyoto-u.ac.jp [Graduate School of Biostudies, Kyoto University, Oiwakecho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)

    2016-08-12

    Macroautophagy, or autophagy, is a cellular response in which unnecessary cytoplasmic components, including lipids and organelles, are self-degraded. Recent studies closely related autophagy to activation of hepatic stellate cells (HSCs), a process critical in the pathogenesis of liver fibrosis. During HSC activation, cytoplasmic lipid droplets (LDs) are degraded as autophagic cargo, and then cells express fibrogenic genes. Thus, inhibition of autophagy in HSCs is a potential therapeutic approach for attenuating liver fibrosis. We found that tetrandrine, a bisbenzylisoquinoline alkaloid isolated from Stephania tetrandra, induced lipid accumulation, a phenotype associated with quiescent HSCs, through blockade of autophagy in the rat-derived HSC line HSC-T6. Tetrandrine inhibited autophagic flux without affecting lysosomal function. A phenotypic comparison using siRNA knockdown suggested that tetrandrine may target regulators, involved in fusion between autophagosomes and lysosomes (e.g., syntaxin 17). Moreover, perilipin 1, an LD-coated protein, co-localized specifically with LC3, a marker protein for autophagosomes, in tetrandrine-treated HSC-T6 cells. This suggests a potential role for perilipin 1 in autophagy-mediated LD degradation in HSCs. Our results identified tetrandrine as a potential tool for prevention and treatment of HSC activation. - Highlights: • Autophagy is closely related to lipid degradation in hepatic stellate cells. • Tetrandrine (Tet) causes lipid accumulation via blockade of autophagy in HSC-T6 cells. • Tet blocked autophagy without affecting lysosomal function unlike bafilomycin A{sub 1}. • Perilipin 1 was specifically co-localized with LC3 in Tet-treated cells. • Perilipin 1 may play potential roles in autophagy-mediated lipid degradation.

  16. GLP-1 analogue improves hepatic lipid accumulation by inducing autophagy via AMPK/mTOR pathway

    Energy Technology Data Exchange (ETDEWEB)

    He, Qin; Sha, Sha; Sun, Lei; Zhang, Jing; Dong, Ming, E-mail: dr_dongming@126.com

    2016-08-05

    The incidence of nonalcoholic fatty liver disease (NAFLD) keeps rising year by year, and NAFLD is rapidly becoming the most common liver disease worldwide. Clinical studies have found that glucagon-like peptide-1 (GLP-1) analogue, liraglutide (LRG), cannot only reduce glucose levels, but also improve hepatic lipase, especially in patients also with type 2 diabetes mellitus (T2DM). In addition, enhancing autophagy decreases lipid accumulation in hepatocytes. The aim of the present study is to explore the effect of LRG on hepatocyte steatosis and the possible role of autophagy. We set up an obesity mouse model with a high-fat diet (HFD) and induced hepatocyte steatosis with free fatty acids (FFA) in human L-O2 cells. LRG and two inhibitors of autophagy, Chloroquine (CQ) and bafilomycin A1 (Baf), were added into each group, respectively. The lipid profiles and morphological modifications of each group were tested. Immunohistochemistry, immunofluorescence staining and transmission electron microscopy (TEM) were used to measure autophagy in this study. The autophagy protein expression of SQSTM1 (P62), and LC3B, along with the signaling pathway proteins of mTOR, phosphorylated mTOR (p-mTOR), AMPK, phosphorylated AMPK (p-AMPK) and Beclin1, were evaluated by western blot. Our results showed that LRG improved hepatocyte steatosis by inducing autophagy, and the AMPK/mTOR pathway is involved. These findings suggest an important mechanism for the positive effects of LRG on hepatic steatosis, and provide new evidence for clinical use of LRG in NAFLD. -- Highlights: •Liraglutide reduces lipid accumulation in hepatic steatosis both in vivo and in vitro. •Autophagy was involved in relieving effects of liraglutide on hepatic steatosis. •AMPK/mTOR pathway was involved in liraglutide-induced autophagy.

  17. GLP-1 analogue improves hepatic lipid accumulation by inducing autophagy via AMPK/mTOR pathway

    International Nuclear Information System (INIS)

    He, Qin; Sha, Sha; Sun, Lei; Zhang, Jing; Dong, Ming

    2016-01-01

    The incidence of nonalcoholic fatty liver disease (NAFLD) keeps rising year by year, and NAFLD is rapidly becoming the most common liver disease worldwide. Clinical studies have found that glucagon-like peptide-1 (GLP-1) analogue, liraglutide (LRG), cannot only reduce glucose levels, but also improve hepatic lipase, especially in patients also with type 2 diabetes mellitus (T2DM). In addition, enhancing autophagy decreases lipid accumulation in hepatocytes. The aim of the present study is to explore the effect of LRG on hepatocyte steatosis and the possible role of autophagy. We set up an obesity mouse model with a high-fat diet (HFD) and induced hepatocyte steatosis with free fatty acids (FFA) in human L-O2 cells. LRG and two inhibitors of autophagy, Chloroquine (CQ) and bafilomycin A1 (Baf), were added into each group, respectively. The lipid profiles and morphological modifications of each group were tested. Immunohistochemistry, immunofluorescence staining and transmission electron microscopy (TEM) were used to measure autophagy in this study. The autophagy protein expression of SQSTM1 (P62), and LC3B, along with the signaling pathway proteins of mTOR, phosphorylated mTOR (p-mTOR), AMPK, phosphorylated AMPK (p-AMPK) and Beclin1, were evaluated by western blot. Our results showed that LRG improved hepatocyte steatosis by inducing autophagy, and the AMPK/mTOR pathway is involved. These findings suggest an important mechanism for the positive effects of LRG on hepatic steatosis, and provide new evidence for clinical use of LRG in NAFLD. -- Highlights: •Liraglutide reduces lipid accumulation in hepatic steatosis both in vivo and in vitro. •Autophagy was involved in relieving effects of liraglutide on hepatic steatosis. •AMPK/mTOR pathway was involved in liraglutide-induced autophagy.

  18. Enterovirus 71 induces autophagy by regulating has-miR-30a expression to promote viral replication.

    Science.gov (United States)

    Fu, Yuxuan; Xu, Wentao; Chen, Deyan; Feng, Chunhong; Zhang, Li; Wang, Xiaohui; Lv, Xiaowen; Zheng, Nan; Jin, Yu; Wu, Zhiwei

    2015-12-01

    Enterovirus 71 (EV71), the etiological agent of hand-foot-and-mouth disease, has increasingly become a public health challenge around the world. Previous studies reported that EV71 infection can induce autophagic machinery to enhance viral replication in vitro and in vivo, but did not address the underlying mechanisms. Increasing evidence suggests that autophagy, in a virus-specific manner, may function to degrade viruses or facilitate viral replication. In this study, we reported that EV71 infection of human epidermoid carcinoma (Hep2) and African green monkey kidney cells (Vero) induced autophagy, which is beneficial for viral replication. Our investigation of the mechanisms revealed that EV71 infection resulted in the reduction of cellular miR-30a, which led to the inhibition of Beclin-1, a key autophagy-promoting gene that plays important roles at the early phase of autophagosome formation. We provided further evidence that by modulating cellular miR-30a level through either overexpression or inhibition, one can inhibit or promote EV71 replication, respectively, through regulating autophagic activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Thrombin preferentially induces autophagy in glia cells in the rat central nervous system.

    Science.gov (United States)

    Hu, Shukun; Wu, Gang; Ding, Xin; Zhang, Yi

    2016-09-06

    Autophagy widely occurs after intracerebral hemorrhage (ICH). In our previous study, we demonstrated that thrombin, a serine protease produced after hematoma, contributes to ICH-induced autophagy. However, whether thrombin plays a neuronal and/or astrocytic role in autophagy induction is largely unknown. Here, we examined the autophagic role of thrombin on neurons and glia cells, respectively. In vivo, we found that intracaudate injection of thrombin specifically elevated the astrocytic expression of beclin-1 and LC3, two autophagic markers, and promoted the formation of autophagic vacuoles within astrocytes rather than neurons in the ipsilateral basal ganglia. Consistent with this, thrombin enhanced the LC3-II level and increased the number of MDC-labeled autophagic vacuoles in cultured astrocytes. These results indicated that thrombin preferentially activated astrocytic autophagy after ICH, and therefore provided novel insights into the pathophysiological mechanisms and therapeutic targets for hemorrhage stroke and brain trauma. Copyright © 2016. Published by Elsevier Ireland Ltd.

  20. Mycobacterium tuberculosis induces the miR-33 locus to reprogram autophagy and host lipid metabolism.

    Science.gov (United States)

    Ouimet, Mireille; Koster, Stefan; Sakowski, Erik; Ramkhelawon, Bhama; van Solingen, Coen; Oldebeken, Scott; Karunakaran, Denuja; Portal-Celhay, Cynthia; Sheedy, Frederick J; Ray, Tathagat Dutta; Cecchini, Katharine; Zamore, Philip D; Rayner, Katey J; Marcel, Yves L; Philips, Jennifer A; Moore, Kathryn J

    2016-06-01

    Mycobacterium tuberculosis (Mtb) survives in macrophages by evading delivery to the lysosome and promoting the accumulation of lipid bodies, which serve as a bacterial source of nutrients. We found that by inducing the microRNA (miRNA) miR-33 and its passenger strand miR-33*, Mtb inhibited integrated pathways involved in autophagy, lysosomal function and fatty acid oxidation to support bacterial replication. Silencing of miR-33 and miR-33* by genetic or pharmacological means promoted autophagy flux through derepression of key autophagy effectors (such as ATG5, ATG12, LC3B and LAMP1) and AMPK-dependent activation of the transcription factors FOXO3 and TFEB, which enhanced lipid catabolism and Mtb xenophagy. These data define a mammalian miRNA circuit used by Mtb to coordinately inhibit autophagy and reprogram host lipid metabolism to enable intracellular survival and persistence in the host.

  1. S6K1 controls autophagosome maturation in autophagy induced by sulforaphane or serum deprivation.

    Science.gov (United States)

    Hać, Aleksandra; Domachowska, Anna; Narajczyk, Magdalena; Cyske, Karolina; Pawlik, Anna; Herman-Antosiewicz, Anna

    2015-10-01

    It is well established that mTORC1 suppresses autophagy by phosphorylation and inactivation of proteins involved in autophagosome formation. However, the role of its substrate, p70S6 kinase1 (S6K1), in autophagy is quite controversial. In some models S6K1 activity correlates with autophagy suppression, however, some other studies show that S6K1 promotes rather than inhibits this process. Here, we investigated the role of S6K1 in prostate cancer cells (PC-3) and non-cancerous, mouse embryonic fibroblasts (MEF), either treated with autophagy inducer sulforaphane, an isothiocyanate derived from cruciferous plants, or deprived of serum. Our results indicate that constitutively active S6K1 decreases the level of LC3 processing and foci formation by autophagosomal vacuoles in cells treated with sulforaphane. On the other hand, presence of S6K1 is necessary for autophagosome maturation under conditions of autophagy induced by either sulforaphane or serum deprivation. Diminished level of S6K1 or lack of S6 kinases results in both, accumulation of autophagosomes and drop in the autophagolysosome number, and thus disturbs autophagy flux under stress conditions. Moreover, lack of S6 kinases reduces cell survival under stress conditions. Copyright © 2015 Elsevier GmbH. All rights reserved.

  2. Implications of Therapy-Induced Selective Autophagy on Tumor Metabolism and Survival

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    Luke R. K. Hughson

    2012-01-01

    Full Text Available Accumulating evidence indicates that therapies designed to trigger apoptosis in tumor cells cause mitochondrial depolarization, nuclear damage, and the accumulation of misfolded protein aggregates, resulting in the activation of selective forms of autophagy. These selective forms of autophagy, including mitophagy, nucleophagy, and ubiquitin-mediated autophagy, counteract apoptotic signals by removing damaged cellular structures and by reprogramming cellular energy metabolism to cope with therapeutic stress. As a result, the efficacies of numerous current cancer therapies may be improved by combining them with adjuvant treatments that exploit or disrupt key metabolic processes induced by selective forms of autophagy. Targeting these metabolic irregularities represents a promising approach to improve clinical responsiveness to cancer treatments given the inherently elevated metabolic demands of many tumor types. To what extent anticancer treatments promote selective forms of autophagy and the degree to which they influence metabolism are currently under intense scrutiny. Understanding how the activation of selective forms of autophagy influences cellular metabolism and survival provides an opportunity to target metabolic irregularities induced by these pathways as a means of augmenting current approaches for treating cancer.

  3. Heme oxygenase-1 enhances autophagy in podocytes as a protective mechanism against high glucose-induced apoptosis

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    Dong, Chenglong [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Zheng, Haining [Department of Hyperbaric Oxygen, Nanjing General Hospital of Nanjing Military Command, Nanjing (China); Huang, Shanshan; You, Na; Xu, Jiarong; Ye, Xiaolong; Zhu, Qun; Feng, Yamin; You, Qiang; Miao, Heng [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Ding, Dafa, E-mail: dingdafa2004@aliyun.com [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Lu, Yibing, E-mail: luyibing2004@126.com [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China)

    2015-10-01

    Injury and loss of podocytes play vital roles in diabetic nephropathy progression. Emerging evidence suggests autophagy, which is induced by multiple stressors including hyperglycemia, plays a protective role. Meanwhile, heme oxygenase-1 (HO-1) possesses powerful anti-apoptotic properties. Therefore, we investigated the impact of autophagy on podocyte apoptosis under diabetic conditions and its association with HO-1. Mouse podocytes were cultured in vitro; apoptosis was detected by flow cytometry. Transmission electron microscopy and biochemical autophagic flux assays were used to measure the autophagy markers microtubule-associated protein 1 light chain 3-II (LC3-II) and beclin-1. LC3-II and beclin-1 expression peaked 12–24 h after exposing podocytes to high glucose. Inhibition of autophagy with 3-methyladenine or Beclin-1 siRNAs or Atg 5 siRNAs sensitized cells to apoptosis, suggesting autophagy is a survival mechanism. HO-1 inactivation inhibited autophagy, which aggravated podocyte injury in vitro. Hemin-induced autophagy also protected podocytes from hyperglycemia in vitro and was abrogated by HO-1 siRNA. Adenosine monophosphate-activated protein kinase phosphorylation was higher in hemin-treated and lower in HO-1 siRNA-treated podocytes. Suppression of AMPK activity reversed HO-1-mediated Beclin-1 upregulation and autophagy, indicating HO-1-mediated autophagy is AMPK dependent. These findings suggest HO-1 induction and regulation of autophagy are potential therapeutic targets for diabetic nephropathy. - Highlights: • High glucose leads to increased autophagy in podocytes at an early stage. • The early autophagic response protects against high glucose-induced apoptosis. • Heme oxygenase-1 enhances autophagy and decreases high glucose -mediated apoptosis. • Heme oxygenase-1 induces autophagy through the activation of AMPK.

  4. MIR376A is a regulator of starvation-induced autophagy.

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    Gozde Korkmaz

    Full Text Available Autophagy is a vesicular trafficking process responsible for the degradation of long-lived, misfolded or abnormal proteins, as well as damaged or surplus organelles. Abnormalities of the autophagic activity may result in the accumulation of protein aggregates, organelle dysfunction, and autophagy disorders were associated with various diseases. Hence, mechanisms of autophagy regulation are under exploration.Over-expression of hsa-miR-376a1 (shortly MIR376A was performed to evaluate its effects on autophagy. Autophagy-related targets of the miRNA were predicted using Microcosm Targets and MIRanda bioinformatics tools and experimentally validated. Endogenous miRNA was blocked using antagomirs and the effects on target expression and autophagy were analyzed. Luciferase tests were performed to confirm that 3' UTR sequences in target genes were functional. Differential expression of MIR376A and the related MIR376B was compared using TaqMan quantitative PCR.Here, we demonstrated that, a microRNA (miRNA from the DLK1/GTL2 gene cluster, MIR376A, played an important role in autophagy regulation. We showed that, amino acid and serum starvation-induced autophagy was blocked by MIR376A overexpression in MCF-7 and Huh7 cells. MIR376A shared the same seed sequence and had overlapping targets with MIR376B, and similarly blocked the expression of key autophagy proteins ATG4C and BECN1 (Beclin 1. Indeed, 3' UTR sequences in the mRNA of these autophagy proteins were responsive to MIR376A in luciferase assays. Antagomir tests showed that, endogenous MIR376A was participating to the control of ATG4C and BECN1 transcript and protein levels. Moreover, blockage of endogenous MIR376A accelerated starvation-induced autophagic activity. Interestingly, MIR376A and MIR376B levels were increased with different kinetics in response to starvation stress and tissue-specific level differences were also observed, pointing out to an overlapping but miRNA-specific biological role

  5. Carnosol induces ROS-mediated beclin1-independent autophagy and apoptosis in triple negative breast cancer.

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    Yusra Al Dhaheri

    Full Text Available In this study we investigated the in vitro and in vivo anticancer effect of carnosol, a naturally occurring polyphenol, in triple negative breast cancer.We found that carnosol significantly inhibited the viability and colony growth induced G2 arrest in the triple negative MDA-MB-231. Blockade of the cell cycle was associated with increased p21/WAF1 expression and downregulation of p27. Interestingly, carnosol was found to induce beclin1-independent autophagy and apoptosis in MDA-MB-231 cells. The coexistence of both events, autophagy and apoptosis, was confirmed by electron micrography. Induction of autophagy was found to be an early event, detected within 3 h post-treatment, which subsequently led to apoptosis. Carnosol treatment also caused a dose-dependent increase in the levels of phosphorylated extracellular signal-regulated kinase 1 and 2 (pERK1/2. Moreover, we show that carnosol induced DNA damage, reduced the mitochondrial potential and triggered the activation of the intrinsic and extrinsic apoptotic pathway. Furthermore, we found that carnosol induced a dose-dependent generation of reactive oxygen species (ROS and inhibition of ROS by tiron, a ROS scavenger, blocked the induction of autophagy and apoptosis and attenuated DNA damage. To our knowledge, this is the first report to identify the induction of autophagy by carnosol.In conclusion our findings provide strong evidence that carnosol may be an alternative therapeutic candidate against the aggressive form of breast cancer and hence deserves more exploration.

  6. Carnosol Induces ROS-Mediated Beclin1-Independent Autophagy and Apoptosis in Triple Negative Breast Cancer

    Science.gov (United States)

    Al Dhaheri, Yusra; Attoub, Samir; Ramadan, Gaber; Arafat, Kholoud; Bajbouj, Khuloud; Karuvantevida, Noushad; AbuQamar, Synan; Eid, Ali; Iratni, Rabah

    2014-01-01

    Background In this study we investigated the in vitro and in vivo anticancer effect of carnosol, a naturally occurring polyphenol, in triple negative breast cancer. Results We found that carnosol significantly inhibited the viability and colony growth induced G2 arrest in the triple negative MDA-MB-231. Blockade of the cell cycle was associated with increased p21/WAF1 expression and downregulation of p27. Interestingly, carnosol was found to induce beclin1-independent autophagy and apoptosis in MDA-MB-231 cells. The coexistence of both events, autophagy and apoptosis, was confirmed by electron micrography. Induction of autophagy was found to be an early event, detected within 3 h post-treatment, which subsequently led to apoptosis. Carnosol treatment also caused a dose-dependent increase in the levels of phosphorylated extracellular signal-regulated kinase 1 and 2 (pERK1/2). Moreover, we show that carnosol induced DNA damage, reduced the mitochondrial potential and triggered the activation of the intrinsic and extrinsic apoptotic pathway. Furthermore, we found that carnosol induced a dose-dependent generation of reactive oxygen species (ROS) and inhibition of ROS by tiron, a ROS scavenger, blocked the induction of autophagy and apoptosis and attenuated DNA damage. To our knowledge, this is the first report to identify the induction of autophagy by carnosol. Conclusion In conclusion our findings provide strong evidence that carnosol may be an alternative therapeutic candidate against the aggressive form of breast cancer and hence deserves more exploration. PMID:25299698

  7. Autophagy Is Rapidly Induced by Salt Stress and Is Required for Salt Tolerance in Arabidopsis

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    Liming Luo

    2017-08-01

    Full Text Available Salinity stress challenges agriculture and food security globally. Upon salt stress, plant growth slows down, nutrients are recycled, osmolytes are produced, and reallocation of Na+ takes place. Since autophagy is a high-throughput degradation pathway that contributes to nutrient remobilization in plants, we explored the involvement of autophagic flux in salt stress response of Arabidopsis with various approaches. Confocal microscopy of GFP-ATG8a in transgenic Arabidopsis showed that autophagosome formation is induced shortly after salt treatment. Immunoblotting of ATG8s and the autophagy receptor NBR1 confirmed that the level of autophagy peaks within 30 min of salt stress, and then settles to a new homeostasis in Arabidopsis. Such an induction is absent in mutants defective in autophagy. Within 3 h of salt treatment, accumulation of oxidized proteins is alleviated in the wild-type; however, such a reduction is not seen in atg2 or atg7. Consistently, the Arabidopsis atg mutants are hypersensitive to both salt and osmotic stresses, and plants overexpressing ATG8 perform better than the wild-type in germination assays. Quantification of compatible osmolytes further confirmed that the autophagic flux contributes to salt stress adaptation. Imaging of intracellular Na+ revealed that autophagy is required for Na+ sequestration in the central vacuole of root cortex cells following salt treatment. These data suggest that rapid protein turnover through autophagy is a prerequisite for salt stress tolerance in Arabidopsis.

  8. Kibra and aPKC regulate starvation-induced autophagy in Drosophila

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    Jin, Ahrum [Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of); Neufeld, Thomas P. [Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455 (United States); Choe, Joonho, E-mail: jchoe@kaist.ac.kr [Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141 (Korea, Republic of)

    2015-12-04

    Autophagy is a bulk degradation system that functions in response to cellular stresses such as metabolic stress, endoplasmic reticulum stress, oxidative stress, and developmental processes. During autophagy, cytoplasmic components are captured in double-membrane vesicles called autophagosomes. The autophagosome fuses with the lysosome, producing a vacuole known as an autolysosome. The cellular components are degraded by lysosomal proteases and recycled. Autophagy is important for maintaining cellular homeostasis, and the process is evolutionarily conserved. Kibra is an upstream regulator of the hippo signaling pathway, which controls organ size by affecting cell growth, proliferation, and apoptosis. Kibra is mainly localized in the apical membrane domain of epithelial cells and acts as a scaffold protein. We found that Kibra is required for autophagy to function properly. The absence of Kibra caused defects in the formation of autophagic vesicles and autophagic degradation. We also found that the well-known cell polarity protein aPKC interacts with Kibra, and its activity affects autophagy upstream of Kibra. Constitutively active aPKC decreased autophagic vesicle formation and autophagic degradation. We confirmed the interaction between aPKC and Kibra in S2 cells and Drosophila larva. Taken together, our data suggest that Kibra and aPKC are essential for regulating starvation-induced autophagy. - Highlights: • Loss of Kibra causes defects in autophagosome formation and autophagic degradation. • Constitutively-active aPKCs negatively regulate autophagy. • Kibra interacts with aPKC in vitro and in vivo. • Kibra regulates autophagy downstream of aPKC.

  9. Kibra and aPKC regulate starvation-induced autophagy in Drosophila

    International Nuclear Information System (INIS)

    Jin, Ahrum; Neufeld, Thomas P.; Choe, Joonho

    2015-01-01

    Autophagy is a bulk degradation system that functions in response to cellular stresses such as metabolic stress, endoplasmic reticulum stress, oxidative stress, and developmental processes. During autophagy, cytoplasmic components are captured in double-membrane vesicles called autophagosomes. The autophagosome fuses with the lysosome, producing a vacuole known as an autolysosome. The cellular components are degraded by lysosomal proteases and recycled. Autophagy is important for maintaining cellular homeostasis, and the process is evolutionarily conserved. Kibra is an upstream regulator of the hippo signaling pathway, which controls organ size by affecting cell growth, proliferation, and apoptosis. Kibra is mainly localized in the apical membrane domain of epithelial cells and acts as a scaffold protein. We found that Kibra is required for autophagy to function properly. The absence of Kibra caused defects in the formation of autophagic vesicles and autophagic degradation. We also found that the well-known cell polarity protein aPKC interacts with Kibra, and its activity affects autophagy upstream of Kibra. Constitutively active aPKC decreased autophagic vesicle formation and autophagic degradation. We confirmed the interaction between aPKC and Kibra in S2 cells and Drosophila larva. Taken together, our data suggest that Kibra and aPKC are essential for regulating starvation-induced autophagy. - Highlights: • Loss of Kibra causes defects in autophagosome formation and autophagic degradation. • Constitutively-active aPKCs negatively regulate autophagy. • Kibra interacts with aPKC in vitro and in vivo. • Kibra regulates autophagy downstream of aPKC.

  10. IFNB1/interferon-ß-induced autophagy in MCF-7 breast cancer cells counteracts its proapoptotic function

    DEFF Research Database (Denmark)

    Ambjørn, Malene; Ejlerskov, Patrick; Liu, Yawei

    2013-01-01

    differs significantly from type I IFNs, can induce autophagy, no such function for any type I IFN has been reported. We show here that IFNB1 induces autophagy in MCF-7, MDAMB231 and SKBR3 breast cancer cells by measuring the turnover of two autophagic markers, MAP1LC3B/LC3 and SQSTM1/p62. The induction...... of autophagy in MCF-7 cells occurred upstream of the negative regulator of autophagy MTORC1, and autophagosome formation was dependent on the known core autophagy molecule ATG7 and the IFNB1 signaling molecule STAT1. Using siRNA-mediated silencing of several core autophagy molecules and STAT1, we provide...

  11. [Effect of starvation-induced autophagy on cell cycle of tumor cells].

    Science.gov (United States)

    Ge, Jun-Na; Huang, Dan; Xiao, Tian; Wang, Zun; Li, Xiao-Lan; Xiao, Hui; Tao, De-Ding; Gong, Jian-Ping

    2008-08-01

    No serum starvation could induce autophagy and cell cycle arrest. Although autophagy and cell cycle have been widely explored, little is known about their relationship. This study was to observe the change of Cyclin expression during starvation-induced autophagy to discuss the effect of autophagy on cell cycle. In control group, HeLa cells were treated with d-Hanks solution (a medium with no serum). In experiment group, HeLa cells were treated with d-Hanks solution containing 3-methyladenine (3-MA, a specific inhibitor of autophagy). Cells were harvested after being starved for 0, 3, 6 and 12 h. Flow cytometry (FCM) and Weston blot were used to detect Cyclin and microtubule-associated protein 1 light chain 3(LC-3) which marked autophagy specifically. In control group, the expression of LC-3 protein was detected early after being starved for 3 h, and gradually increased along with starvation; the expression of Cyclin D3 and Cyclin E was decreased evidently after a short-time starvation (3 h) and descended to the minimum when cells were being starved for 6 h; the expression of Cyclin A and Cyclin B1 were apparently decreased after being starved for 6 h. In experiment group, LC-3 protein could not be detected during starvation when cells were exposed to 3-MA and the down-regulation of Cyclins was suppressed. Autophagy is involved in starvation-induced hydrolysis of Cyclins. The hydrolysis of Cyclin D3 and Cyclin E is quicker than that of Cyclin A and Cyclin B1.

  12. Deferoxamine-Induced Migration and Odontoblast Differentiation via ROS-Dependent Autophagy in Dental Pulp Stem Cells

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    Xuan Wang

    2017-11-01

    Full Text Available Background/Aims: As a vital degradation and recycling system, autophagy plays an essential role in regulating the differentiation of stem cells. We previously showed that iron chelator deferoxamine (DFO could promote the repair ability of dental pulp stem cells (DPSCs. Here, we investigated the effect of DFO in autophagy and the role of autophagy in regulating the migration and odontoblast differentiation of DPSCs. Methods: Transmission electron microscopy, immunofluorescence staining and western blotting were performed to evaluate the autophagic activity of DPSCs. Transmigration assay, alkaline phosphatase staining/activity, alizarin red S staining and quantitative PCR were performed to examine the migration and odontoblast differentiation of DPSCs. Reactive oxygen species (ROS levels and the effects of ROS scavenger in autophagy induction were also detected. Autophagy inhibitors (3-MA and bafilomycin A1 and lentiviral vectors carrying ATG5 shRNA sequences were used for autophagy inhibition. Results: Early exposure to DFO promoted the mineralization of DPSCs and increased autophagic activity. Autophagy inhibition suppressed DFO-induced DPSC migration and odontoblast differentiation. Furthermore, DFO treatment could induce autophagy partly through hypoxia-inducible factor 1α/B cell lymphoma 2/adenovirus E1B 19K-interacting protein 3 (HIF-1α/BNIP3 pathway in a ROS-dependent manner. Conclusion: DFO increased DPSC migration and differentiation, which might be modulated through ROS-induced autophagy.

  13. Autophagy plays a critical role in ChLym-1-induced cytotoxicity of non-hodgkin's lymphoma cells.

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    Jiajun Fan

    Full Text Available Autophagy is a critical mechanism in both cancer therapy resistance and tumor suppression. Monoclonal antibodies have been documented to kill tumor cells via apoptosis, antibody-dependent cellular cytotoxicity (ADCC and complement-dependent cytotoxicity (CDC. In this study, we report for the first time that chLym-1, a chimeric anti-human HLA-DR monoclonal antibody, induces autophagy in Raji Non-Hodgkin's Lymphoma (NHL cells. Interestingly, inhibition of autophagy by pharmacological inhibitors (3-methyladenine and NH4Cl or genetic approaches (siRNA targeting Atg5 suppresses chLym-1-induced growth inhibition, apoptosis, ADCC and CDC in Raji cells, while induction of autophagy could accelerate cytotoxic effects of chLym-1 on Raji cells. Furthermore, chLym-1-induced autophagy can mediate apoptosis through Caspase 9 activation, demonstrating the tumor-suppressing role of autophagy in antilymphoma effects of chLym-1. Moreover, chLym-1 can activate several upstream signaling pathways of autophagy including Akt/mTOR and extracellular signal-regulated kinase 1/2 (Erk1/2. These results elucidate the critical role of autophagy in cytotoxicity of chLym-1 antibody and suggest a potential therapeutic strategy of NHL therapy by monoclonal antibody chLym-1 in combination with autophagy inducer.

  14. EVA1A inhibits GBM cell proliferation by inducing autophagy and apoptosis

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    Shen, Xue; Kan, Shifeng; Liu, Zhen [Department of Cell Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191 (China); Lu, Guang [Department of Cell Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191 (China); Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597 (Singapore); Zhang, Xiaoyan [Department of Cell Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191 (China); Chen, Yingyu [Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191 (China); Peking University Center for Human Disease Genomics, Beijing 100191 (China); Bai, Yun, E-mail: baiyun@bjmu.edu.cn [Department of Cell Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191 (China)

    2017-03-01

    Eva-1 homolog A (EVA1A) is a novel lysosome and endoplasmic reticulum-associated protein involved in autophagy and apoptosis. In this study, we constructed a recombinant adenovirus 5-EVA1A vector (Ad5-EVA1A) to overexpress EVA1A in glioblastoma (GBM) cell lines and evaluated its anti-tumor activities in vitro and in vivo. We found that overexpression of EVA1A in three GBM cell lines (U251, U87 and SHG44) resulted in a suppression of tumor cell growth via activation of autophagy and induction of cell apoptosis in a dose- and time-dependent manner. EVA1A-mediated autophagy was associated with inactivation of the mTOR/RPS6KB1 signaling pathway. Furthermore in vivo, overexpression of EVA1A successfully inhibited tumor growth in NOD/SCID mice. Our data suggest that EVA1A-induced autophagy and apoptosis play a role in suppressing the development of GBM and their up-regulation may be an effective method for treating this form of cancer. - Highlights: • Overexpression of EVA1A suppresses GBM cell growth. • EVA1A induces autophagy through the mTOR/RPS6KB1 pathway. • EVA1A induces GBM cell apoptosis. • EVA1A inhibits the development of GBM in vivo.

  15. Characterization of the autophagy marker protein Atg8 reveals atypical features of autophagy in Plasmodium falciparum.

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    Rahul Navale

    Full Text Available Conventional autophagy is a lysosome-dependent degradation process that has crucial homeostatic and regulatory functions in eukaryotic organisms. As malaria parasites must dispose a number of self and host cellular contents, we investigated if autophagy in malaria parasites is similar to the conventional autophagy. Genome wide analysis revealed a partial autophagy repertoire in Plasmodium, as homologs for only 15 of the 33 yeast autophagy proteins could be identified, including the autophagy marker Atg8. To gain insights into autophagy in malaria parasites, we investigated Plasmodium falciparum Atg8 (PfAtg8 employing techniques and conditions that are routinely used to study autophagy. Atg8 was similarly expressed and showed punctate localization throughout the parasite in both asexual and sexual stages; it was exclusively found in the pellet fraction as an integral membrane protein, which is in contrast to the yeast or mammalian Atg8 that is distributed among cytosolic and membrane fractions, and suggests for a constitutive autophagy. Starvation, the best known autophagy inducer, decreased PfAtg8 level by almost 3-fold compared to the normally growing parasites. Neither the Atg8-associated puncta nor the Atg8 expression level was significantly altered by treatment of parasites with routinely used autophagy inhibitors (cysteine (E64 and aspartic (pepstatin protease inhibitors, the kinase inhibitor 3-methyladenine, and the lysosomotropic agent chloroquine, indicating an atypical feature of autophagy. Furthermore, prolonged inhibition of the major food vacuole protease activity by E64 and pepstatin did not cause accumulation of the Atg8-associated puncta in the food vacuole, suggesting that autophagy is primarily not meant for degradative function in malaria parasites. Atg8 showed partial colocalization with the apicoplast; doxycycline treatment, which disrupts apicoplast, did not affect Atg8 localization, suggesting a role, but not exclusive, in

  16. Hypoxia inducible factor 1α contributes to regulation of autophagy in retinal detachment

    Science.gov (United States)

    Shelby, Shameka J.; Angadi, Pavan S.; Zheng, Qiong-Duon; Yao, Jingyu; Jia, Lin; Zacks, David N.

    2015-01-01

    Photoreceptor (PR) cells receive oxygen and nutritional support from the underlying retinal pigment epithelium (RPE). Retinal detachment results in PR hypoxia and their time-dependent death. Detachment also activates autophagy within the PR, which serves to reduce the rate of PR apoptosis. In this study, we test the hypothesis that autophagy activation in the PR results, at least in part, from the detachment-induced activation of hypoxia-inducible factors (HIF). Retina-RPE separation was created in Brown-Norway rats and C57BL/6J mice by injection of 1% hyaluronic acid into the subretinal space. Retinas were harvested and assayed for HIF protein levels. Cultured 661W photoreceptor cells were subjected to hypoxic conditions and assayed for induction of HIF and autophagy. The requirement of HIF-1α and HIF-2α in regulating photoreceptor autophagy was tested using siRNA in vitro and in vivo. We observed increased levels of HIF-1α and HIF-2α within 1 day post-detachment, as well as increased levels of BNIP3, a downstream target of HIF-1α that contributes to autophagy activation. Exposing 661W cells to hypoxia resulted in increased HIF-1α and HIF-2α levels and increase in conversion of LC3-I to LC3-II. Silencing of HIF-1α, but not HIF-2α, reduced the hypoxia-induced increase in LC3-II formation and increased cell death in 661W cells. Silencing of HIF-1α in rat retinas prevented the detachment-induced increase in BNIP3 and LC3-II, resulting in increased PR cell death. Our data support the hypothesis that HIF-1α, but not HIF-2α, serves as an early response signal to induce autophagy and reduce photoreceptor cell death. PMID:26093278

  17. MDM2 Inhibitor, Nutlin 3a, Induces p53 Dependent Autophagy in Acute Leukemia by AMP Kinase Activation.

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    Gautam Borthakur

    Full Text Available MDM2 (mouse double minute 2 inhibitors that activate p53 and induce apoptosis in a non-genotoxic manner are in clinical development for treatment of leukemias. P53 can modulate other programmed cell death pathways including autophagy both transcriptionally and non-transcriptionally. We investigated autophagy induction in acute leukemia by Nutlin 3a, a first-in-class MDM2 inhibitor. Nutlin 3a induced autophagy in a p53 dependent manner and transcriptional activation of AMP kinase (AMPK is critical, as this effect is abrogated in AMPK -/- mouse embryonic fibroblasts. Nutlin 3a induced autophagy appears to be pro-apoptotic as pharmacological (bafilomycin or genetic inhibition (BECLIN1 knockdown of autophagy impairs apoptosis induced by Nutlin 3a.

  18. Essential role for the ATG4B protease and autophagy in bleomycin-induced pulmonary fibrosis

    Science.gov (United States)

    Cabrera, Sandra; Maciel, Mariana; Herrera, Iliana; Nava, Teresa; Vergara, Fabián; Gaxiola, Miguel; López-Otín, Carlos; Selman, Moisés; Pardo, Annie

    2015-01-01

    Autophagy is a critical cellular homeostatic process that controls the turnover of damaged organelles and proteins. Impaired autophagic activity is involved in a number of diseases, including idiopathic pulmonary fibrosis suggesting that altered autophagy may contribute to fibrogenesis. However, the specific role of autophagy in lung fibrosis is still undefined. In this study, we show for the first time, how autophagy disruption contributes to bleomycin-induced lung fibrosis in vivo using an Atg4b-deficient mouse as a model. Atg4b-deficient mice displayed a significantly higher inflammatory response at 7 d after bleomycin treatment associated with increased neutrophilic infiltration and significant alterations in proinflammatory cytokines. Likewise, we found that Atg4b disruption resulted in augmented apoptosis affecting predominantly alveolar and bronchiolar epithelial cells. At 28 d post-bleomycin instillation Atg4b-deficient mice exhibited more extensive and severe fibrosis with increased collagen accumulation and deregulated extracellular matrix-related gene expression. Together, our findings indicate that the ATG4B protease and autophagy play a crucial role protecting epithelial cells against bleomycin-induced stress and apoptosis, and in the regulation of the inflammatory and fibrotic responses. PMID:25906080

  19. Cytotoxic Autophagy in Cancer Therapy

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    Khushboo Sharma

    2014-06-01

    Full Text Available Autophagy is a process of cellular self-digestion, whereby the cell degrades subcellular materials in order to generate energy and metabolic precursors in order to prolong survival, classically under conditions of nutrient deprivation. Autophagy can also involve the degradation of damaged or aged organelles, and misfolded or damaged proteins to eliminate these components that might otherwise be deleterious to cellular survival. Consequently, autophagy has generally been considered a prosurvival response. Many, if not most chemotherapeutic drugs and radiation also promote autophagy, which is generally considered a cytoprotective response, in that its inhibition frequently promotes apoptotic cells death. Furthermore, it has been shown that conventional chemotherapeutic drugs and radiation alone rarely induce a form of autophagy that leads to cell death. However, there are multiple examples in the literature where newer chemotherapeutic agents, drug combinations or drugs in combination with radiation promote autophagic cell death. This review will describe autophagic cell death induced in breast tumor cells, lung cancer cells as well as glioblastoma, demonstrating that it cannot be concluded that stress induced autophagy is, of necessity, cytoprotective in function.

  20. Estrogen receptor α induces prosurvival autophagy in papillary thyroid cancer via stimulating reactive oxygen species and extracellular signal regulated kinases.

    Science.gov (United States)

    Fan, Dahua; Liu, Shirley Y W; van Hasselt, C Andrew; Vlantis, Alexander C; Ng, Enders K W; Zhang, Haitao; Dong, Yujuan; Ng, Siu Kwan; Chu, Ryan; Chan, Amy B W; Du, Jing; Wei, Wei; Liu, Xiaoling; Liu, Zhimin; Xing, Mingzhao; Chen, George G

    2015-04-01

    The incidence of papillary thyroid cancer (PTC) shows a predominance in females, with a male:female ratio of 1:3, and none of the known risk factors are associated with gender difference. Increasing evidence indicates a role of estrogen in thyroid tumorigenesis, but the mechanism involved remains largely unknown. This study aimed to assess the contribution of autophagy to estrogen receptor α (ERα)-mediated growth of PTC. The expression of ERα in thyroid tissue of patients with PTC tissues was analyzed. Cell viability, proliferation, and apoptosis were evaluated after chemical and genetic inhibition of autophagy. Autophagy in PTC cell lines BCPAP and BCPAP-ERα was assessed. ERα expression was increased in PTC tissues compared with the adjacent nontumor tissues. Estrogen induced autophagy in an ERα-dependent manner. Autophagy induced by estrogen/ERα is associated with generation of reactive oxygen species, activation of ERK1/2, and the survival/growth of PTC cells. Chemical and genetic inhibition of autophagy dramatically decreased tumor cell survival and promoted apoptosis, confirming the positive role of autophagy in the growth of PTC. ERα contributes to the growth of PTC by enhancing an important prosurvival catabolic process, autophagy, in PTC cells. The inhibition of autophagy promotes apoptosis, implicating a novel strategy for the treatment of ERα-positive PTC.

  1. Arsenite-induced autophagy is associated with proteotoxicity in human lymphoblastoid cells

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    Bolt, Alicia M.; Zhao, Fei; Pacheco, Samantha; Klimecki, Walter T., E-mail: klimecki@pharmacy.arizona.edu

    2012-10-15

    Epidemiological studies of arsenic-exposed populations have provided evidence that arsenic exposure in humans is associated with immunosuppression. Previously, we have reported that arsenite-induced toxicity is associated with the induction of autophagy in human lymphoblastoid cell lines (LCL). Autophagy is a cellular process that functions in the degradation of damaged cellular components, including protein aggregates formed by misfolded or damaged proteins. Accumulation of misfolded or damaged proteins in the endoplasmic reticulum (ER) lumen causes ER stress and activates the unfolded protein response (UPR). In an effort to investigate the mechanism of autophagy induction by arsenite in the LCL model, we examined the potential contribution of ER stress and activation of the UPR. LCL exposed to sodium arsenite for 8-days induced expression of UPR-activated genes, including CHOP and GRP78, at the RNA and the protein level. Evidence for activation of the three arms of the UPR was observed. The arsenite-induced activation of the UPR was associated with an accumulation of protein aggregates containing p62 and LC3, proteins with established roles in the sequestration and autophagic clearance of protein aggregates. Taken together, these data provide evidence that arsenite-induced autophagy is associated with the generation of ER stress, activation of the UPR, and formation of protein aggregates that may be targeted to the lysosome for degradation. -- Highlights: ► Arsenite induces endoplasmic reticulum stress and the unfolded protein response. ► Arsenite induces the formation of protein aggregates that contain p62 and LC3-II. ► Time-course data suggests that arsenite-induced autophagy precedes ER stress.

  2. Arsenite-induced autophagy is associated with proteotoxicity in human lymphoblastoid cells

    International Nuclear Information System (INIS)

    Bolt, Alicia M.; Zhao, Fei; Pacheco, Samantha; Klimecki, Walter T.

    2012-01-01

    Epidemiological studies of arsenic-exposed populations have provided evidence that arsenic exposure in humans is associated with immunosuppression. Previously, we have reported that arsenite-induced toxicity is associated with the induction of autophagy in human lymphoblastoid cell lines (LCL). Autophagy is a cellular process that functions in the degradation of damaged cellular components, including protein aggregates formed by misfolded or damaged proteins. Accumulation of misfolded or damaged proteins in the endoplasmic reticulum (ER) lumen causes ER stress and activates the unfolded protein response (UPR). In an effort to investigate the mechanism of autophagy induction by arsenite in the LCL model, we examined the potential contribution of ER stress and activation of the UPR. LCL exposed to sodium arsenite for 8-days induced expression of UPR-activated genes, including CHOP and GRP78, at the RNA and the protein level. Evidence for activation of the three arms of the UPR was observed. The arsenite-induced activation of the UPR was associated with an accumulation of protein aggregates containing p62 and LC3, proteins with established roles in the sequestration and autophagic clearance of protein aggregates. Taken together, these data provide evidence that arsenite-induced autophagy is associated with the generation of ER stress, activation of the UPR, and formation of protein aggregates that may be targeted to the lysosome for degradation. -- Highlights: ► Arsenite induces endoplasmic reticulum stress and the unfolded protein response. ► Arsenite induces the formation of protein aggregates that contain p62 and LC3-II. ► Time-course data suggests that arsenite-induced autophagy precedes ER stress.

  3. Fluoride induces oxidative damage and SIRT1/autophagy through ROS-mediated JNK signaling.

    Science.gov (United States)

    Suzuki, Maiko; Bandoski, Cheryl; Bartlett, John D

    2015-12-01

    Fluoride is an effective caries prophylactic, but at high doses can also be an environmental health hazard. Acute or chronic exposure to high fluoride doses can result in dental enamel and skeletal and soft tissue fluorosis. Dental fluorosis is manifested as mottled, discolored, porous enamel that is susceptible to dental caries. Fluoride induces cell stress, including endoplasmic reticulum stress and oxidative stress, which leads to impairment of ameloblasts responsible for dental enamel formation. Recently we reported that fluoride activates SIRT1 and autophagy as an adaptive response to protect cells from stress. However, it still remains unclear how SIRT1/autophagy is regulated in dental fluorosis. In this study, we demonstrate that fluoride exposure generates reactive oxygen species (ROS) and the resulting oxidative damage is counteracted by SIRT1/autophagy induction through c-Jun N-terminal kinase (JNK) signaling in ameloblasts. In the mouse-ameloblast-derived cell line LS8, fluoride induced ROS, mitochondrial damage including cytochrome-c release, up-regulation of UCP2, attenuation of ATP synthesis, and H2AX phosphorylation (γH2AX), which is a marker of DNA damage. We evaluated the effects of the ROS inhibitor N-acetylcysteine (NAC) and the JNK inhibitor SP600125 on fluoride-induced SIRT1/autophagy activation. NAC decreased fluoride-induced ROS generation and attenuated JNK and c-Jun phosphorylation. NAC decreased SIRT1 phosphorylation and formation of the autophagy marker LC3II, which resulted in an increase in the apoptosis mediators γH2AX and cleaved/activated caspase-3. SP600125 attenuated fluoride-induced SIRT1 phosphorylation, indicating that fluoride activates SIRT1/autophagy via the ROS-mediated JNK pathway. In enamel organs from rats or mice treated with 50, 100, or 125 ppm fluoride for 6 weeks, cytochrome-c release and the DNA damage markers 8-oxoguanine, p-ATM, and γH2AX were increased compared to those in controls (0 ppm fluoride). These

  4. Fluoride induces oxidative damage and SIRT1/autophagy through ROS-mediated JNK signaling

    Science.gov (United States)

    Suzuki, Maiko; Bandoski, Cheryl; Bartlett, John D.

    2015-01-01

    Fluoride is an effective caries prophylactic, but at high doses can also be an environmental health hazard. Acute or chronic exposure to high fluoride doses can result in dental enamel and skeletal and soft tissue fluorosis. Dental fluorosis is manifested as mottled, discolored, porous enamel that is susceptible to dental caries. Fluoride induces cell stress, including endoplasmic reticulum stress and oxidative stress, which leads to impairment of ameloblasts responsible for dental enamel formation. Recently we reported that fluoride activates SIRT1 and autophagy as an adaptive response to protect cells from stress. However, it still remains unclear how SIRT1/autophagy is regulated in dental fluorosis. In this study, we demonstrate that fluoride exposure generates reactive oxygen species (ROS) and the resulting oxidative damage is counteracted by SIRT1/autophagy induction through c-Jun N-terminal kinase (JNK) signaling in ameloblasts. In the mouse-ameloblast-derived cell line LS8, fluoride induced ROS, mitochondrial damage including cytochrome-c release, up-regulation of UCP2, attenuation of ATP synthesis, and H2AX phosphorylation (γH2AX), which is a marker of DNA damage. We evaluated the effects of the ROS inhibitor N-acetylcysteine (NAC) and the JNK inhibitor SP600125 on fluoride-induced SIRT1/autophagy activation. NAC decreased fluoride-induced ROS generation and attenuated JNK and c-Jun phosphorylation. NAC decreased SIRT1 phosphorylation and formation of the autophagy marker LC3II, which resulted in an increase in the apoptosis mediators γH2AX and cleaved/activated caspase-3. SP600125 attenuated fluoride-induced SIRT1 phosphorylation, indicating that fluoride activates SIRT1/autophagy via the ROS-mediated JNK pathway. In enamel organs from rats or mice treated with 50, 100, or 125 ppm fluoride for 6 weeks, cytochrome-c release and the DNA damage markers 8-oxoguanine, p-ATM, and γH2AX were increased compared to those in controls (0 ppm fluoride). These

  5. Beclin1-induced autophagy abrogates radioresistance of lung cancer cells by suppressing osteopontin

    International Nuclear Information System (INIS)

    Chang, Seung-Hee; Minai-Tehrani, Arash; Shin, Ji-Young

    2012-01-01

    Osteopontin (OPN) serves as an indicator of resistance to radiotherapy. However, the role of OPN in the development of acquired radioresistance in human lung cancer cells has not yet been fully elucidated. Therefore, the potential importance of OPN as a marker of lung cancer with a potential significant role in the development of radioresistance against repeated radiotherapy has prompted us to define the pathways by which OPN regulates lung cancer cell growth. In addition, autophagy has been reported to play a key role in the radiosensitization of cancer cells. Here, we report that increased OPN expression through induction of nuclear p53 following irradiation was inhibited by exogenous beclin-1 (BECN1). Our results clearly show that BECN1 gene expression led to induction of autophagy and inhibition of cancer cell growth and angiogenesis. Our results suggest that the induction of autophagy abrogated the radioresistance of the cancer cells. Interestingly, we showed that knockdown of OPN by lentivirus-mediated shRNA induced the autophagy of human lung cancer cell. Taken together, these results suggest that OPN and BECN1 can be molecular targets for overcoming radioresistance by controlling autophagy. (author)

  6. β-Elemene-induced autophagy protects human gastric cancer cells from undergoing apoptosis

    International Nuclear Information System (INIS)

    Liu, Jing; Zhang, Ye; Qu, Jinglei; Xu, Ling; Hou, Kezuo; Zhang, Jingdong; Qu, Xiujuan; Liu, Yunpeng

    2011-01-01

    β-Elemene, a compound found in an herb used in traditional Chinese medicine, has shown promising anti-cancer effects against a broad spectrum of tumors. The mechanism by which β-elemene kills cells remains unclear. The aim of the present study is to investigate the anti-tumor effect of β-elemene on human gastric cancer cells and the molecular mechanism involved. β-Elemene inhibited the viability of human gastric cancer MGC803 and SGC7901 cells in a dose-dependent manner. The suppression of cell viability was due to the induction of apoptosis. A robust autophagy was observed in the cells treated with β-elemene; it was characterized by the increase of punctate LC3 dots, the cellular morphology, and the increased levels of LC3-II protein. Further study showed that β-elemene treatment up-regulated Atg5-Atg12 conjugated protein but had little effect on other autophagy-related proteins. PI3K/Akt/mTOR/p70S6K1 activity was inhibited by β-elemene. Knockdown of Beclin 1 with small interfering RNA, or co-treatment with the autophagy inhibitor, 3-methyladenine or chlorochine enhanced significantly the antitumor effects of β-elemene. Our data provides the first evidence that β-elemene induces protective autophagy and prevents human gastric cancer cells from undergoing apoptosis. A combination of β-elemene with autophagy inhibitor might thus be a useful therapeutic option for advanced gastric cancer

  7. Evaluation of autophagy as a mechanism involved in air pollutant-induced pulmonary injury

    Science.gov (United States)

    Evaluation of autophagy as a mechanism involved in air pollutant-induced pulmonary injuryHenriquez, A.1, Snow, S.2, Miller, D1.,Schladweiler, M.2 and Kodavanti, U2.1 Curriculum in Toxicology, UNC, Chapel Hill, NC. 2 EPHD/NHEERL, US EPA, RTP, Durham, NC. ...

  8. The flavonoid luteolin enhances doxorubicin-induced autophagy in human osteosarcoma U2OS cells.

    Science.gov (United States)

    Zhang, Baoliang; Yu, Xin; Xia, Hong

    2015-01-01

    Luteolin (LUT), a flavone, which is universally present as constituent of medicinal plants as well as some vegetables and spices, has been demonstrated display specific anti-carcinogenic effects. However, the mechanisms by which LUT inhibits human osteosarcoma growth remain unknown. The effects of LUT on cell growth in human osteosarcoma U2OS cells were measured by MTT assay and flowcytometry. The effects of LUT on morphological markers of autophagy in U2OS were analyzed by fluorescence microscopy and electron microscopy. Autophagic markers, beclin1 and LC3 were detected by western blotting. Here, we found that LUT induced autophagy in U2OS and acted as an enhancer to sensitize doxorubicin (DOX)-mediated autophagy signaling. The combined treatment of LUT and DOX greatly decreases the growth of U2OS, showing synergistic cytotoxicity. Our results indicate that LUT in combination with DOX maybe a novel strategy for the treatment of human osteosarcoma.

  9. Autophagy induced by snakehead fish vesiculovirus inhibited its replication in SSN-1 cell line.

    Science.gov (United States)

    Wang, Yao; Chen, Nan; Hegazy, Abeer M; Liu, Xiaodan; Wu, Zhixin; Liu, Xueqin; Zhao, Lijuan; Qin, Qiwei; Lan, Jiangfeng; Lin, Li

    2016-08-01

    Autophagy plays an important role in host protection against pathogen infection through activating innate and adaptive immunity. In the present study, we observed that the infection of snakehead fish vesiculovirus (SHVV) could induce apparent autophagy in striped snakehead fish cell line (SSN-1), including clear double-membrane vesicles, fluorescent punctate pattern of microtubule-associated protein 1 light chain 3B (SSN-LC3B) and the conversion of SSN-LC3B-Ⅰ to SSN-LC3B-Ⅱ. Furthermore, we verified that autophagy inhibited the replication of SHVV by assessing mRNA and protein level of nucleoprotein as well as virus titer in the supernatant. These results will shed a new light on the prevention of the infection of SHVV. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Magnetic ferroferric oxide nanoparticles induce vascular endothelial cell dysfunction and inflammation by disturbing autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lu, E-mail: chaperones@163.com [College of Bioengineering, Henan University of Technology, Lianhua Street, Zhengzhou 450001 (China); Wang, XueQin; Miao, YiMing; Chen, ZhiQiang; Qiang, PengFei; Cui, LiuQing; Jing, Hongjuan [College of Bioengineering, Henan University of Technology, Lianhua Street, Zhengzhou 450001 (China); Guo, YuQi [Department of Obstetrics and Gynecology, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou 450052 (China)

    2016-03-05

    Highlights: • B-Fe{sub 3}O{sub 4}NPs did not induce cell apoptosis or necrosis in HUVECs within 24 h. • B-Fe{sub 3}O{sub 4}NPs induced HUVEC dysfunction and inflammation. • B-Fe{sub 3}O{sub 4}NPs induced enhanced autophagic activity and blockade of autophagy flux. • Suppression of autophagy dysfunction attenuated B-Fe{sub 3}O{sub 4}NP-induced HUVEC dysfunction. - Abstract: Despite the considerable use of magnetic ferroferric oxide nanoparticles (Fe{sub 3}O{sub 4}NPs) worldwide, their safety is still an important topic of debate. In the present study, we detected the toxicity and biological behavior of bare-Fe{sub 3}O{sub 4}NPs (B-Fe{sub 3}O{sub 4}NPs) on human umbilical vascular endothelial cells (HUVECs). Our results showed that B-Fe{sub 3}O{sub 4}NPs did not induce cell death within 24 h even at concentrations up to 400 μg/ml. The level of nitric oxide (NO) and the activity of endothelial NO synthase (eNOS) were decreased after exposure to B-Fe{sub 3}O{sub 4}NPs, whereas the levels of proinflammatory cytokines were elevated. Importantly, B-Fe{sub 3}O{sub 4}NPs increased the accumulation of autophagosomes and LC3-II in HUVECs through both autophagy induction and the blockade of autophagy flux. The levels of Beclin 1 and VPS34, but not phosphorylated mTOR, were increased in the B-Fe{sub 3}O{sub 4}NP-treated HUVECs. Suppression of autophagy induction or stimulation of autophagy flux, at least partially, attenuated the B-Fe{sub 3}O{sub 4}NP-induced HUVEC dysfunction. Additionally, enhanced autophagic activity might be linked to the B-Fe{sub 3}O{sub 4}NP-induced production of proinflammatory cytokines. Taken together, these results demonstrated that B-Fe{sub 3}O{sub 4}NPs disturb the process of autophagy in HUVECs, and eventually lead to endothelial dysfunction and inflammation.

  11. DNA damage and autophagy

    International Nuclear Information System (INIS)

    Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Panayiotidis, Mihalis I.; Franco, Rodrigo

    2011-01-01

    Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

  12. The pancreatitis-associated protein VMP1, a key regulator of inducible autophagy, promotes KrasG12D-mediated pancreatic cancer initiation

    Science.gov (United States)

    Loncle, C; Molejon, M I; Lac, S; Tellechea, J I; Lomberk, G; Gramatica, L; Fernandez Zapico, M F; Dusetti, N; Urrutia, R; Iovanna, J L

    2016-01-01

    Both clinical and experimental evidence have firmly established that chronic pancreatitis, in particular in the context of Kras oncogenic mutations, predisposes to pancreatic ductal adenocarcinoma (PDAC). However, the repertoire of molecular mediators of pancreatitis involved in Kras-mediated initiation of pancreatic carcinogenesis remains to be fully defined. In this study we demonstrate a novel role for vacuole membrane protein 1 (VMP1), a pancreatitis-associated protein critical for inducible autophagy, in the regulation of Kras-induced PDAC initiation. Using a newly developed genetically engineered model, we demonstrate that VMP1 increases the ability of Kras to give rise to preneoplastic lesions, pancreatic intraepithelial neoplasias (PanINs). This promoting effect of VMP1 on PanIN formation is due, at least in part, by an increase in cell proliferation combined with a decrease in apoptosis. Using chloroquine, an inhibitor of autophagy, we show that this drug antagonizes the effect of VMP1 on PanIN formation. Thus, we conclude that VMP1-mediated autophagy cooperate with Kras to promote PDAC initiation. These findings are of significant medical relevance, molecules targeting autophagy are currently being tested along chemotherapeutic agents to treat PDAC and other tumors in human trials. PMID:27415425

  13. Autophagy contributes to falcarindiol-induced cell death in breast cancer cells with enhanced endoplasmic reticulum stress.

    Directory of Open Access Journals (Sweden)

    Tingting Lu

    Full Text Available Falcarindiol (FAD is a natural polyyne have been found in many food and dietary plants. It has been found to have various beneficial biological activities. In this study, we demonstrated its anticancer function and mechanism in breast cancer cells. We found that FAD preferentially induces cell death in breast cancer cells. FAD-induced cell death is caspase-dependent. However, FAD induces autophagy to contribute to the cell death. Blocking autophagy by either chemical inhibitors or genetic knockout of autophagy signaling component inhibits FAD-induced cell death. We further found that FAD-induced cell death is mediated by the induction of endoplasmic reticulum stress. We also identified that FAD has synergistic effect with approved cancer drugs 5-FU and Bortezomib in killing breast cancer cells. Summarily, these data demonstrate that FAD has strong and specific anticancer effect in breast cancer cells, and provide some insights about the roles of autophagy in FAD-induced cell death.

  14. Autophagy contributes to falcarindiol-induced cell death in breast cancer cells with enhanced endoplasmic reticulum stress.

    Science.gov (United States)

    Lu, Tingting; Gu, Ming; Zhao, Yan; Zheng, Xinyu; Xing, Chengzhong

    2017-01-01

    Falcarindiol (FAD) is a natural polyyne have been found in many food and dietary plants. It has been found to have various beneficial biological activities. In this study, we demonstrated its anticancer function and mechanism in breast cancer cells. We found that FAD preferentially induces cell death in breast cancer cells. FAD-induced cell death is caspase-dependent. However, FAD induces autophagy to contribute to the cell death. Blocking autophagy by either chemical inhibitors or genetic knockout of autophagy signaling component inhibits FAD-induced cell death. We further found that FAD-induced cell death is mediated by the induction of endoplasmic reticulum stress. We also identified that FAD has synergistic effect with approved cancer drugs 5-FU and Bortezomib in killing breast cancer cells. Summarily, these data demonstrate that FAD has strong and specific anticancer effect in breast cancer cells, and provide some insights about the roles of autophagy in FAD-induced cell death.

  15. Autophagy is activated in compression-induced cell degeneration and is mediated by reactive oxygen species in nucleus pulposus cells exposed to compression.

    Science.gov (United States)

    Ma, K-G; Shao, Z-W; Yang, S-H; Wang, J; Wang, B-C; Xiong, L-M; Wu, Q; Chen, S-F

    2013-12-01

    To determine whether autophagy contributes to the pathogenesis of degenerative disc disease (DDD) or retards the intervertebral disc (IVD) degeneration, and investigate the possible relationship between compression-induced autophagy and intracellular reactive oxygen species (ROS) in nucleus pulposus (NP) cells in vitro. The autophagosome and autophagy-related markers were used to explore the role of autophagy in rat NP cells under compressive stress, which were measured directly by electronic microscopy, monodansylcadaverine (MDC) staining, immunofluorescence, western blot, and indirectly by analyzing the impact of pharmacological inhibitors of autophagy such as 3-methyladenine (3-MA) and chloroquine (CQ). And the relationship between autophagy and apoptosis was investigated by Annexin-V/propidium iodide (PI)-fluorescein staining. In addition, ROS were measured to determine whether these factors are responsible for the development of compression-induced autophagy. Our results indicated that rat NP cells activated autophagy in response to the same strong apoptotic stimuli that triggered apoptosis by compression. Autophagy and apoptosis were interconnected and coordinated in rat NP cells exposed to compression stimuli. Compression-induced autophagy was closely related to intracellular ROS production. Enhanced degradation of damaged components of NP cells by autophagy may be a crucial survival response against mechanical overload, and extensive autophagy may trigger autophagic cell death. Regulating autophagy and reducing the generation of intracellular ROS may retard IVD degeneration. Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  16. Selective taste of ethanol-induced autophagy for mitochondria and lipid droplets.

    Science.gov (United States)

    Ding, Wen-Xing; Li, Min; Yin, Xiao-Ming

    2011-02-01

    Alcoholic beverages are one of the most popular drinks in the world, but ethanol can induce significant liver pathology. We have found that ethanol treatment results in autophagy activation, which is at least in part due to the inhibition of mTOR signaling by reactive oxygen species. Autophagy is important in limiting liver injury and hepatocyte apoptosis by removing damaged mitochondria and accumulated lipid droplets, the two most important culprits of ethanol pathogenesis. The selectivity of ethanol-induced autophagy toward these two targets without affecting other cellular substances, such as long-lived proteins, is remarkably in line with its protective effects. However, we still do not quite understand how this selectivity is determined and how the selection process is accomplished, although evidence from other studies indicates that mitophagy involves distinct molecular steps of mobilization of the autophagy machinery and of preparation of mitochondria for recognition. The avoidance of mistargeting to other cellular components may involve additional mechanisms related to how autophagosomes might form in relation to their targets. Ethanol-induced selective mitophagy and lipophagy thus provides an excellent model to study these events in a pathophysiology-relevant context. Most importantly, the understanding of the mechanisms can bring forward new therapeutic modalities to improve the disease outcome.

  17. The role of HBV-induced autophagy in HBV replication and HBV related-HCC.

    Science.gov (United States)

    Xie, Mingjie; Yang, Zhenggang; Liu, Yanning; Zheng, Min

    2018-04-27

    Hepatitis B virus (HBV) is infecting about 364 million people around the world. It can cause various diseases, such as chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). However, the present anti-viral treatment in clinics is limited; studies for new therapies are highly desired. Autophagy is a crucial and major catabolic process in the maintenance of normal intracellular homeostasis in host cells. Host cells use this unique process to degrade and recycle long-lived proteins, damaged organelles, and various pathogens for keeping the normal physiological functions. Recently, published studies indicated that HBV can induce autophagy in host cells; this autophagic response is involved in viral replication and pathogenesis. Several viral proteins, such as surface and X proteins, are assumed to be responsible for inducing autophagy in HBV infection. This review briefly summarizes some important mechanisms involved in HBV-induced autophagy and provides a novel perspective on therapies of HBV infection and HBV-related HCC. Copyright © 2017. Published by Elsevier Inc.

  18. Autophagy Alleviates Melamine-Induced Cell Death in PC12 Cells Via Decreasing ROS Level.

    Science.gov (United States)

    Wang, Hui; Gao, Na; Li, Zhigui; Yang, Zhuo; Zhang, Tao

    2016-04-01

    Since melamine was illegally added to raw milk for increasing the apparent protein content, such a scandal has not been quite blown out. Previous studies showed that melamine induced apoptosis and oxidative damage in both in vivo and in vitro experiments. It is well known that autophagy is closely related to oxidative stress. In the present study, we examined whether autophagy played an important role in protecting PC12 cells, which were damaged by melamine. Immunofluorescence assay showed that melamine enhanced the number of punctuate dot, indicating the increase of autophagosomes. Western blot assay presented that melamine significantly elevated the expression level of autophagy markers including LC3-II/LC3-I ratio, beclin-1, and Atg 7. Rapamycin further enhanced the effect, whereas 3-methyadenine (3-MA) inhibited it. MTT assay exhibited that rapamycin significantly enhanced the cell viability (P PC12 cells (P cells (P PC12 cells (P cells (P PC12 cells from melamine-induced cell death via inhibiting the excessive generation of ROS. Regulating autophagy may become a new targeted therapy to relieve the damage induced by melamine.

  19. Heteronemin, a Spongean Sesterterpene, Induces Cell Apoptosis and Autophagy in Human Renal Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Szu-Ying Wu

    2015-01-01

    Full Text Available Heteronemin is a bioactive marine sesterterpene isolated from the sponge Hyrtios sp. Previous reports have shown that heteronemin possesses anticancer activity. Here, heteronemin displayed cytotoxic effects against three human cancer cell lines (A549, ACHN, and A498 and exhibited potent activity in A498 human renal carcinoma cells, with an IC50 value of 1.57 μM by MTT assay and a GI50 value of 0.77 μM by SRB assay. Heteronemin initiates apoptotic cell death by downregulating Bcl-2 and Bcl-xL and upregulating Bax, leading to the disruption of the mitochondrial membrane potential and the release of cytochrome c from the mitochondria. These effects were associated with the activation of caspase-3/caspase-8/caspase-9, followed by PARP cleavage. Furthermore, heteronemin inhibited the phosphorylation of AKT signaling pathway and ERK and activated p38 and JNK. The specific inhibition of the p38 pathway by SB203580 or p38 siRNA treatment reversed the heteronemin-induced cytotoxicity and apoptotic signaling. Heteronemin also induced autophagy in A498 cells, and treatment with chloroquine (autophagy inhibitor or SP600125 (JNK inhibitor inhibited autophagy and increased heteronemin-induced cytotoxicity and apoptotic signaling. Taken together, this study proposes a novel treatment paradigm in which the combination of heteronemin and autophagy inhibitors leads to enhanced RCC cell apoptosis.

  20. PTEN Activation by DNA Damage Induces Protective Autophagy in Response to Cucurbitacin B in Hepatocellular Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Yanan Niu

    2016-01-01

    Full Text Available Cucurbitacin B (Cuc B, a natural product, induced both protective autophagy and DNA damage mediated by ROS while the detailed mechanisms remain unclear. This study explored the mechanism of Cuc B-induced DNA damage and autophagy. Cuc B decreased cell viability in concentration- and time-dependent manners. Cuc B caused long comet tails and increased expression of γ-H2AX, phosphorylation of ATM/ATR, and Chk1/Chk2. Cuc B induced autophagy as evidenced by monodansylcadaverine (MDC staining, increased expression of LC3II, phosphorylated ULK1, and decreased expression of phosphorylated AKT, mTOR. Cuc B induced apoptosis mediated by Bcl-2 family proteins and caspase activation. Furthermore, Cuc B induced ROS formation, which was inhibited by N-acetyl-L-cysteine (NAC. NAC pretreatment dramatically reversed Cuc B-induced DNA damage, autophagy, and apoptosis. Cuc B-induced apoptosis was reversed by NAC but enhanced by 3-methyladenine (3-MA, chloroquine (CQ, and silencing phosphatase and tensin homolog (PTEN. 3-MA and CQ showed no effect on Cuc B-induced DNA damage. In addition, Cuc B increased PTEN phosphorylation and silence PTEN restored Cuc B-induced autophagic protein expressions without affecting DNA damage. In summary, Cuc B induced DNA damage, apoptosis, and protective autophagy mediated by ROS. PTEN activation in response to DNA damage bridged DNA damage and prosurvival autophagy.

  1. Short-chain fatty acids induced autophagy serves as an adaptive strategy for retarding mitochondria-mediated apoptotic cell death

    OpenAIRE

    Tang, Y; Chen, Y; Jiang, H; Nie, D

    2010-01-01

    Short-chain fatty acids (SCFAs) are the major by-products of bacterial fermentation of undigested dietary fibers in the large intestine. SCFAs, mostly propionate and butyrate, inhibit proliferation and induce apoptosis in colon cancer cells, but clinical trials had mixed results regarding the anti-tumor activities of SCFAs. Herein we demonstrate that propionate and butyrate induced autophagy in human colon cancer cells to dampen apoptosis whereas inhibition of autophagy potentiated SCFA induc...

  2. Newly synthesized bis-benzimidazole compound 8 induces apoptosis, autophagy and reactive oxygen species generation in HeLa cells.

    Science.gov (United States)

    Chu, Naying; Yao, Guodong; Liu, Yuan; Cheng, Maosheng; Ikejima, Takashi

    2016-09-01

    Compound 8 (C8) is a newly synthesized bis-benzimidazole derivative and exerts significant anti-tumor activity in vitro. Previous studies demonstrated that C8 induced apoptosis and autophagy in human promyelocytic leukemia HL60 cells. However, cytotoxicity study on human peripheral blood mononuclear cells (hPBMC) showed that C8 exhibited less toxicity in normal cells. In this study, the molecular mechanism of C8 on human cervical carcinoma HeLa cells was investigated. The results showed that C8 inhibited the growth of HeLa cells and triggered both apoptotic and autophagic cell death. Subsequent experiment also indicated that reactive oxygen species (ROS) generation was induced in C8-treated HeLa cells. Since ROS scavenger decreased the ratio of apoptotic and autophagic cells, ROS generation contributed to C8-induced apoptosis and autophagy. Furthermore, inhibitors of apoptosis and autophagy also reduced ROS generation, respectively. Autophagy inhibition increased cell growth compared to C8-treated group and attenuated apoptotic cell death, indicating that C8-induced autophagy promoted apoptosis for cell death. However, the percentage of autophagic cells was enhanced when limiting apoptosis process. Taken together, C8 induced ROS-mediated apoptosis and autophagy in HeLa cells, autophagy promoted apoptosis but the former was antagonized by the latter. The data also gave us a new perspective on the anti-tumor effect of C8. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Cardiac-Specific Overexpression of Catalase Attenuates Lipopolysaccharide-Induced Myocardial Contractile Dysfunction: Role of Autophagy

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    Turdi, Subat; Han, Xuefeng; Huff, Anna F.; Roe, Nathan D.; Hu, Nan; Gao, Feng; Ren, Jun

    2012-01-01

    Lipopolysaccharide (LPS) from Gram-negative bacteria is a major initiator of sepsis, leading to cardiovascular collapse. Accumulating evidence has indicated a role of reactive oxygen species (ROS) in cardiovascular complication in sepsis. This study was designed to examine the effect of cardiac-specific overexpression of catalase in LPS-induced cardiac contractile dysfunction and the underlying mechanism(s) with a focus on autophagy. Catalase transgenic and wild-type FVB mice were challenged with LPS (6 mg/kg) and cardiac function was evaluated. Levels of oxidative stress, autophagy, apoptosis and protein damage were examined using fluorescence microscopy, Western blot, TUNEL assay, caspase-3 activity and carbonyl formation. Kaplan-Meier curve was constructed for survival following LPS treatment. Our results revealed a lower mortality in catalase mice compared with FVB mice following LPS challenge. LPS injection led to depressed cardiac contractile capacity as evidenced by echocardiography and cardiomyocyte contractile function, the effect of which was ablated by catalase overexpression. LPS treatment induced elevated TNF-α level, autophagy, apoptosis (TUNEL, caspase-3 activation, cleaved caspase-3), production of ROS and O2−, and protein carbonyl formation, the effects of which were significantly attenuated by catalase overexpression. Electron microscopy revealed focal myocardial damage characterized by mitochondrial injury following LPS treatment, which was less severe in catalase mice. Interestingly, LPS-induced cardiomyocyte contractile dysfunction was prevented by antioxidant NAC and the autophagy inhibitor 3-methyladenine. Taken together, our data revealed that catalase protects against LPS-induced cardiac dysfunction and mortality, which may be associated with inhibition of oxidative stress and autophagy. PMID:22902401

  4. Cardiac-specific overexpression of catalase attenuates lipopolysaccharide-induced myocardial contractile dysfunction: role of autophagy.

    Science.gov (United States)

    Turdi, Subat; Han, Xuefeng; Huff, Anna F; Roe, Nathan D; Hu, Nan; Gao, Feng; Ren, Jun

    2012-09-15

    Lipopolysaccharide (LPS) from gram-negative bacteria is a major initiator of sepsis, leading to cardiovascular collapse. Accumulating evidence has indicated a role of reactive oxygen species (ROS) in cardiovascular complications in sepsis. This study was designed to examine the effect of cardiac-specific overexpression of catalase in LPS-induced cardiac contractile dysfunction and the underlying mechanism(s) with a focus on autophagy. Catalase transgenic and wild-type FVB mice were challenged with LPS (6 mg/kg) and cardiac function was evaluated. Levels of oxidative stress, autophagy, apoptosis, and protein damage were examined using fluorescence microscopy, Western blot, TUNEL assay, caspase-3 activity, and carbonyl formation. A Kaplan-Meier curve was constructed for survival after LPS treatment. Our results revealed a lower mortality in catalase mice compared with FVB mice after LPS challenge. LPS injection led to depressed cardiac contractile capacity as evidenced by echocardiography and cardiomyocyte contractile function, the effect of which was ablated by catalase overexpression. LPS treatment induced elevated TNF-α level, autophagy, apoptosis (TUNEL, caspase-3 activation, cleaved caspase-3), production of ROS and O(2)(-), and protein carbonyl formation, the effects of which were significantly attenuated by catalase overexpression. Electron microscopy revealed focal myocardial damage characterized by mitochondrial injury after LPS treatment, which was less severe in catalase mice. Interestingly, LPS-induced cardiomyocyte contractile dysfunction was prevented by the antioxidant N-acetylcysteine and the autophagy inhibitor 3-methyladenine. Taken together, our data revealed that catalase protects against LPS-induced cardiac dysfunction and mortality, which may be associated with inhibition of oxidative stress and autophagy. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Roles of autophagy in MPP+-induced neurotoxicity in vivo: the involvement of mitochondria and α-synuclein aggregation.

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    Kai-Chih Hung

    Full Text Available Macroautophagy (also known as autophagy is an intracellular self-eating mechanism and has been proposed as both neuroprotective and neurodestructive in the central nervous system (CNS neurodegenerative diseases. In the present study, the role of autophagy involving mitochondria and α-synuclein was investigated in MPP+ (1-methyl-4-phenylpyridinium-induced oxidative injury in chloral hydrate-anesthetized rats in vivo. The oxidative mechanism underlying MPP+-induced neurotoxicity was identified by elevated lipid peroxidation and heme oxygenase-1 levels, a redox-regulated protein in MPP+-infused substantia nigra (SN. At the same time, MPP+ significantly increased LC3-II levels, a hallmark protein of autophagy. To block MPP+-induced autophagy in rat brain, Atg7siRNA was intranigrally infused 4 d prior to MPP+ infusion. Western blot assay showed that in vivo Atg7siRNA transfection not only reduced Atg7 levels in the MPP+-infused SN but attenuated MPP+-induced elevation in LC3-II levels, activation of caspase 9 and reduction in tyrosine hydroxylase levels, indicating that autophagy is pro-death. The immunostaining study demonstrated co-localization of LC3 and succinate dehydrogenase (a mitochondrial complex II as well as LC3 and α-synuclein, suggesting that autophagy may engulf mitochondria and α-synuclein. Indeed, in vivo Atg7siRNA transfection mitigated MPP+-induced reduction in cytochrome c oxidase. In addition, MPP+-induced autophagy differentially altered the α-synuclein aggregates in the infused SN. In conclusion, autophagy plays a prodeath role in the MPP+-induced oxidative injury by sequestering mitochondria in the rat brain. Moreover, our data suggest that the benefits of autophagy depend on the levels of α-synuclein aggregates in the nigrostriatal dopaminergic system of the rat brain.

  6. Vorinostat-induced autophagy switches from a death-promoting to a cytoprotective signal to drive acquired resistance.

    Science.gov (United States)

    Dupéré-Richer, D; Kinal, M; Ménasché, V; Nielsen, T H; Del Rincon, S; Pettersson, F; Miller, W H

    2013-02-07

    Histone deacetylase inhibitors (HDACi) have shown promising activity against hematological malignancies in clinical trials and have led to the approval of vorinostat for the treatment of cutaneous T-cell lymphoma. However, de novo or acquired resistance to HDACi therapy is inevitable, and their molecular mechanisms are still unclear. To gain insight into HDACi resistance, we developed vorinostat-resistant clones from the hematological cell lines U937 and SUDHL6. Although cross-resistant to some but not all HDACi, the resistant cell lines exhibit dramatically increased sensitivity toward chloroquine, an inhibitor of autophagy. Consistent with this, resistant cells growing in vorinostat show increased autophagy. Inhibition of autophagy in vorinostat-resistant U937 cells by knockdown of Beclin-1 or Lamp-2 (lysosome-associated membrane protein 2) restores sensitivity to vorinostat. Interestingly, autophagy is also activated in parental U937 cells by de novo treatment with vorinostat. However, in contrast to the resistant cells, inhibition of autophagy decreases sensitivity to vorinostat. These results indicate that autophagy can switch from a proapoptotic signal to a prosurvival function driving acquired resistance. Moreover, inducers of autophagy (such as mammalian target of rapamycin inhibitors) synergize with vorinostat to induce cell death in parental cells, whereas the resistant cells remain insensitive. These data highlight the complexity of the design of combination strategies using modulators of autophagy and HDACi for the treatment of hematological malignancies.

  7. Elemene Injection Induced Autophagy Protects Human Hepatoma Cancer Cells from Starvation and Undergoing Apoptosis

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    Yan Lin

    2014-01-01

    Full Text Available Elemene, a compound found in an herb used in traditional Chinese medicine, has shown promising anticancer effects against a broad spectrum of tumors. In an in vivo experiment, we found that apatinib, a tyrosine kinase inhibitor that selectively inhibits VEGFR2, combined with elemene injection (Ele for the treatment of H22 solid tumor in mice resulted in worse effectiveness than apatinib alone. Moreover, Ele could protect HepG2 cells from death induced by serum-free starvation. Further data on the mechanism study revealed that Ele induced protective autophagy and prevented human hepatoma cancer cells from undergoing apoptosis. Proapoptosis effect of Ele was enhanced when proautophagy effect was inhibited by hydroxychloroquine. Above all, Ele has the effect of protecting cancer cells from death either in apatinib induced nutrient deficient environment or in serum-free induced starvation. A combination of elemene injection with autophagy inhibitor might thus be a useful therapeutic option for hepatocellular carcinoma.

  8. Elemene injection induced autophagy protects human hepatoma cancer cells from starvation and undergoing apoptosis.

    Science.gov (United States)

    Lin, Yan; Wang, Keming; Hu, Chunping; Lin, Lin; Qin, Shukui; Cai, Xueting

    2014-01-01

    Elemene, a compound found in an herb used in traditional Chinese medicine, has shown promising anticancer effects against a broad spectrum of tumors. In an in vivo experiment, we found that apatinib, a tyrosine kinase inhibitor that selectively inhibits VEGFR2, combined with elemene injection (Ele) for the treatment of H22 solid tumor in mice resulted in worse effectiveness than apatinib alone. Moreover, Ele could protect HepG2 cells from death induced by serum-free starvation. Further data on the mechanism study revealed that Ele induced protective autophagy and prevented human hepatoma cancer cells from undergoing apoptosis. Proapoptosis effect of Ele was enhanced when proautophagy effect was inhibited by hydroxychloroquine. Above all, Ele has the effect of protecting cancer cells from death either in apatinib induced nutrient deficient environment or in serum-free induced starvation. A combination of elemene injection with autophagy inhibitor might thus be a useful therapeutic option for hepatocellular carcinoma.

  9. Hydrogen sulfide lowers proliferation and induces protective autophagy in colon epithelial cells.

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    Ya C Wu

    Full Text Available Hydrogen sulfide (H(2S is a gaseous bacterial metabolite that reaches high levels in the large intestine. In the present study, the effect of H(2S on the proliferation of normal and cancerous colon epithelial cells was investigated. An immortalized colon epithelial cell line (YAMC and a panel of colon cancer cell lines (HT-29, SW1116, HCT116 were exposed to H(2S at concentrations similar to those found in the human colon. H(2S inhibited normal and cancerous colon epithelial cell proliferation as measured by MTT assay. The anti-mitogenic effect of H(2S was accompanied by G(1-phase cell cycle arrest and the induction of the cyclin-dependent kinase inhibitor p21(Cip. Moreover, exposure to H(2S led to features characteristic of autophagy, including increased formation of LC3B(+ autophagic vacuoles and acidic vesicular organelles as determined by immunofluorescence and acridine orange staining, respectively. Abolition of autophagy by RNA interference targeting Vps34 or Atg7 enhanced the anti-proliferative effect of H(2S. Further mechanistic investigation revealed that H(2S stimulated the phosphorylation of AMP-activated protein kinase (AMPK and inhibited the phosphorylation of mammalian target of rapamycin (mTOR and S6 kinase. Inhibition of AMPK significantly reversed H(2S-induced autophagy and inhibition of cell proliferation. Collectively, we demonstrate that H(2S inhibits colon epithelial cell proliferation and induces protective autophagy via the AMPK pathway.

  10. Luteolin decreases the UVA-induced autophagy of human skin fibroblasts by scavenging ROS

    Science.gov (United States)

    Yan, Miaomiao; Liu, Zhongrong; Yang, Huilan; Li, Cuihua; Chen, Hulin; Liu, Yan; Zhao, Minling; Zhu, Yingjie

    2016-01-01

    Luteolin (LUT) is a flavone, which is universally present as a constituent of traditional Chinese herbs, and certain vegetables and spices, and has been demonstrated to exhibit potent radical scavenging and cytoprotective properties. Although LUT has various beneficial effects on health, the effects of LUT on the protection of skin remain to be fully elucidated. The present study investigated whether LUT can protect human skin fibroblasts (HSFs) from ultraviolet (UV) A irradiation. It was found that, following exposure to different doses of UVA irradiation, the HSFs exhibited autophagy, as observed by fluorescence and transmission electron microscopy, and reactive oxygen species (ROS) bursts, analyzed by flow cytometry, to differing degrees. Following incubation with micromolar concentrations of LUT, ROS production decreased and autophagy gradually declined. In addition, the expression of hypoxia-inducible factor-1α and the classical autophagy-associated proteins, LC3 and Beclin 1 were observed by western blotting. Western blot analysis showed that the expression levels of HIF-1α, LC3-II and Beclin 1 gradually decreased in the UVA-irradiated HSFs following treatment with LUT. These data indicated that UVA-induced autophagy was mediated by ROS, suggesting the possibility of resistance against UV by certain natural antioxidants, including LUT. PMID:27430964

  11. Autophagy involved in lipopolysaccharide-induced foam cell formation is mediated by adipose differentiation-related protein.

    Science.gov (United States)

    Feng, Xuyang; Yuan, Yuan; Wang, Chao; Feng, Jun; Yuan, Zuyi; Zhang, Xiumin; Sui, Wen; Hu, Peizhen; Zheng, Pengfei; Ye, Jing

    2014-01-09

    Autophagy is an essential process for breaking down macromolecules and aged/damaged cellular organelles to maintain cellular energy balance and cellular nutritional status. The idea that autophagy regulates lipid metabolism is an emerging concept with important implications for atherosclerosis. However, the potential role of autophagy and its relationship with lipid metabolism in foam cell formation remains unclear. In this study, we found that autophagy was involved in the lipopolysaccharide (LPS)-induced the formation of foam cells and was at least partially dependent on adipose differentiation-related protein (ADRP). Foam cell formation was evaluated by Oil red O staining. Autophagic activity was determined by immunofluorescence and Western blotting. ADRP gene expression of ADRP was examined by real-time PCR (RT-PCR). The protein expression of ADRP and LC3 was measured using Western blotting analysis. Intracellular cholesterol and triglyceride levels in foam cells were quantitatively measured by enzymatic colorimetric assays. LPS promoted foam cell formation by inducing lipid accumulation in macrophages. The activation of autophagy with rapamycin (Rap) decreased intracellular cholesterol and triglyceride levels, whereas the inhibition of autophagy with 3-methyladenine (3MA) enhanced the accumulation of lipid droplets. Overexpression of ADRP alone increased the formation of foam cells and consequently autophagic activity. In contrast, the inhibitory effects of ADRP activity with siRNA suppressed the activation of autophagy. Taken together, we propose a novel role for ADRP in the regulation of macrophage autophagy during LPS stimulation. We defined a new molecular pathway in which LPS-induced foam cell formation is regulated through autophagy. These findings facilitate the understanding of the role of autophagy in the development of atherosclerosis.

  12. Propionibacterium acnes induces autophagy in keratinocytes: involvement of multiple mechanisms.

    Science.gov (United States)

    Megyeri, Klára; Orosz, László; Bolla, Szilvia; Erdei, Lilla; Rázga, Zsolt; Seprényi, György; Urbán, Edit; Szabó, Kornélia; Kemény, Lajos

    2017-11-27

    Propionibacterium acnes is a dominant member of the cutaneous microbiota. Herein, we evaluate the effects of different P. acnes strains and propionic acid on autophagy in keratinocytes. Our results showed that P. acnes strain 889 altered the architecture of the mitochondrial network, elevated the levels of LC3B-II, Beclin-1 and phospho-AMPKα, stimulated autophagic flux, facilitated intracellular redistribution of LC3B, increased average number of autophagosomes per cell, and enhanced development of acidic vesicular organelles in the HPV-KER cell line. Propionic acid increased the level of phospho-AMPKα, enhanced lipidation of LC3B, stimulated autophagic flux, as well as facilitated translocation of LC3B into autophagosomes in HPV-KER cells. P. acnes strains 889, 6609 and heat-killed strain 889 also stimulated autophagosome formation in primary keratinocytes to varying degrees. These results indicate that cell wall components and secreted propionic acid metabolite of P. acnes evoke mitochondrial damage successively, thereby trigger AMPK-associated activation of autophagy, which in turn facilitates the removal of dysfunctional mitochondria and promotes survival of keratinocytes. Thus, we suggest that low-level colonization of hair follicles with non-invasive P. acnes strains, by triggering a local increase in autophagic activity, might exert a profound effect on several physiological processes responsible for the maintenance of skin tissue homeostasis. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Triptolide induces autophagy and apoptosis through ERK activation in human breast cancer MCF-7 cells.

    Science.gov (United States)

    Gao, Huan; Zhang, Yue; Dong, Lei; Qu, Xiao-Yu; Tao, Li-Na; Zhang, Yue-Ming; Zhai, Jing-Hui; Song, Yan-Qing

    2018-04-01

    To investigate the effects of triptolide (TPI) on proliferation, autophagy and death in human breast cancer MCF-7 cells, and to elucidate the associated molecular mechanisms, intracellular alterations were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays. The results of the MTT assay revealed that TPI significantly reduced the MCF-7 cell survival rate when the concentration was >10 nmol/l. TPI activated a caspase cascade reaction by regulating Bcl-2-associated X protein (Bax), caspase-3 and B-cell lymphoma 2 expression, and promoted programmed cell death via the mitochondrial pathway. The results demonstrated that TPI significantly reduced the cell proliferation rate and viability in a time- and dose-dependent manner, which was confirmed by western blotting and immunofluorescent staining. TPI induced autophagy and influenced p38 mitogen-activated protein kinases, extracellular signal-regulated kinase (Erk)1/2, and mammalian target of rapamycin (mTOR) phosphorylation, which resulted in apoptosis. When cells were treated with a combination of TPI and the Erk1/2 inhibitor U0126, the downregulation of P62 and upregulation of Bax were inhibited, which demonstrated that the inhibition of Erk1/2 reversed the autophagy changes induced by TPI. The results indicated that Erk1/2 activation may be a novel mechanism by which TPI induces autophagy and apoptosis in MCF-7 breast cancer cells. In conclusion, TPI affects the proliferation and apoptosis of MCF-7 cells, potentially via autophagy and p38/Erk/mTOR phosphorylation. The present study offers a novel view of the mechanisms by which TPI regulates cell death.

  14. Luteoloside induces G0/G1 arrest and pro-death autophagy through the ROS-mediated AKT/mTOR/p70S6K signalling pathway in human non-small cell lung cancer cell lines.

    Science.gov (United States)

    Zhou, Menglu; Shen, Shuying; Zhao, Xin; Gong, Xingguo

    2017-12-09

    Autophagy has attracted a great deal of interest in tumour therapy research in recent years. However, the anticancer effect of luteoloside, a naturally occurring flavonoid isolated from the medicinal plant Gentiana macrophylla, on autophagy remains poorly understood in human lung cells. In the present study, we have investigated the anticancer effects of luteoloside on non-small cell lung cancer (NSCLC) cells and demonstrated that luteoloside effectively inhibited cancer cell proliferation, inducing G 0 /G 1 phase arrest associated with reduced expression of CyclinE, CyclinD1 and CDK4; we further found that treatment with luteoloside did not strongly result in apoptotic cell death in NSCLC (A549 and H292) cells. Interestingly, luteoloside induced autophagy in lung cancer cells, which was correlated with the formation of autophagic vacuoles, breakdown of p62, and the overexpression of Beclin-1 and LC3-II, but not in a human bronchial epithelial cell line (BEAS-2B). Notably, pretreatment of cancer cells with 3-MA, an autophagy inhibitor, protected against autophagy and promoted cell viability but not apoptosis. To further clarify whether luteoloside-induced autophagy depended on the PI3K/AKT/mTOR/p70S6K signalling pathway, a major autophagy-suppressive cascade, cells were treated with a combination of AKT inhibitor (LY294002) and mTOR inhibitor (Rap). These results demonstrated that luteoloside induced autophagy in lung cancer cell lines by inhibiting the pathway at p-Akt (Ser473), p-mTOR and p-p70S6K (Thr389). Moreover, we observed that luteoloside-induced cell autophagy was correlated with production of reactive oxygen species (ROS). NAC-mediated protection against ROS clearly implicated ROS in the activation of autophagy and cell death. In addition, the results showed that ROS served as an upstream effector of the PI3K/AKT/mTOR/p70S6K pathway. Taken together, the present study provides new insights into the molecular mechanisms underlying luteoloside-mediated cell

  15. Apoptotic Cell Death Induced by Resveratrol Is Partially Mediated by the Autophagy Pathway in Human Ovarian Cancer Cells.

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    Fangfang Lang

    Full Text Available Resveratrol (trans-3,4,5'-trihydroxystilbene is an active compound in food, such as red grapes, peanuts, and berries. Resveratrol exhibits an anticancer effect on various human cancer cells. However, the mechanism of resveratrol-induced anti-cancer effect at the molecular level remains to be elucidated. In this study, the mechanism underlying the anti-cancer effect of resveratrol in human ovarian cancer cells (OVCAR-3 and Caov-3 was investigated using various molecular biology techniques, such as flow cytometry, western blotting, and RNA interference, with a major focus on the potential role of autophagy in resveratrol-induced apoptotic cell death. We demonstrated that resveratrol induced reactive oxygen species (ROS generation, which triggers autophagy and subsequent apoptotic cell death. Resveratrol induced ATG5 expression and promoted LC3 cleavage. The apoptotic cell death induced by resveratrol was attenuated by both pharmacological and genetic inhibition of autophagy. The autophagy inhibitor chloroquine, which functions at the late stage of autophagy, significantly reduced resveratrol-induced cell death and caspase 3 activity in human ovarian cancer cells. We also demonstrated that targeting ATG5 by siRNA also suppressed resveratrol-induced apoptotic cell death. Thus, we concluded that a common pathway between autophagy and apoptosis exists in resveratrol-induced cell death in OVCAR-3 human ovarian cancer cells.

  16. Autophagy mediates the degradation of synaptic vesicles: A potential mechanism of synaptic plasticity injury induced by microwave exposure in rats.

    Science.gov (United States)

    Hao, Yanhui; Li, Wenchao; Wang, Hui; Zhang, Jing; Yu, Chao; Tan, Shengzhi; Wang, Haoyu; Xu, Xinping; Dong, Ji; Yao, Binwei; Zhou, Hongmei; Zhao, Li; Peng, Ruiyun

    2018-02-03

    To explore how autophagy changes and whether autophagy is involved in the pathophysiological process of synaptic plasticity injury caused by microwave radiation, we established a 30 mW/cm 2 microwave-exposure in vivo model, which caused reversible injuries in rat neurons. Microwave radiation induced cognitive impairment in rats and synaptic plasticity injury in rat hippocampal neurons. Autophagy in rat hippocampal neurons was activated following microwave exposure. Additionally, we observed that synaptic vesicles were encapsulated by autophagosomes, a phenomenon more evident in the microwave-exposed group. Colocation of autophagosomes and synaptic vesicles in rat hippocampal neurons increased following microwave exposure. microwave exposure led to the activation of autophagy in rat hippocampal neurons, and excessive activation of autophagy might damage synaptic plasticity by mediating synaptic vesicle degradation. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Alternaria extract activates autophagy that induces IL-18 release from airway epithelial cells.

    Science.gov (United States)

    Murai, Hiroki; Okazaki, Shintaro; Hayashi, Hisako; Kawakita, Akiko; Hosoki, Koa; Yasutomi, Motoko; Sur, Sanjiv; Ohshima, Yusei

    2015-09-04

    Alternaria alternata is a major outdoor allergen that causes allergic airway diseases. Alternaria extract (ALT-E) has been shown to induce airway epithelial cells to release IL-18 and thereby initiate Th2-type responses. We investigated the underlying mechanisms involved in IL-18 release from ALT-E-stimulated airway epithelial cells. Normal human bronchial epithelial cells and A549 human lung adenocarcinoma cells were stimulated with ALT-E in the presence of different inhibitors of autophagy or caspases. IL-18 levels in culture supernatants were measured by ELISA. The numbers of autophagosomes, an LC3-I to LC3-II conversion, and p62 degradation were determined by immunofluorescence staining and immunoblotting. 3-methyladenine and bafilomycin, which inhibit the formation of preautophagosomal structures and autolysosomes, respectively, suppressed ALT-E-induced IL-18 release by cells, whereas caspase 1 and 8 inhibitors did not. ALT-E-stimulation increased autophagosome formation, LC-3 conversion, and p62 degradation in airway epithelial cells. LPS-stimulation induced the LC3 conversion in A549 cells, but did not induce IL-18 release or p62 degradation. Unlike LPS, ALT-E induced airway epithelial cells to release IL-18 via an autophagy dependent, caspase 1 and 8 independent pathway. Although autophagy has been shown to negatively regulate canonical inflammasome activity in TLR-stimulated macrophages, our data indicates that this process is an unconventional mechanism of IL-18 secretion by airway epithelial cells. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Autophagy, Metabolism, and Cancer.

    Science.gov (United States)

    White, Eileen; Mehnert, Janice M; Chan, Chang S

    2015-11-15

    Macroautophagy (autophagy hereafter) captures intracellular proteins and organelles and degrades them in lysosomes. The degradation breakdown products are released from lysosomes and recycled into metabolic and biosynthetic pathways. Basal autophagy provides protein and organelle quality control by eliminating damaged cellular components. Starvation-induced autophagy recycles intracellular components into metabolic pathways to sustain mitochondrial metabolic function and energy homeostasis. Recycling by autophagy is essential for yeast and mammals to survive starvation through intracellular nutrient scavenging. Autophagy suppresses degenerative diseases and has a context-dependent role in cancer. In some models, cancer initiation is suppressed by autophagy. By preventing the toxic accumulation of damaged protein and organelles, particularly mitochondria, autophagy limits oxidative stress, chronic tissue damage, and oncogenic signaling, which suppresses cancer initiation. This suggests a role for autophagy stimulation in cancer prevention, although the role of autophagy in the suppression of human cancer is unclear. In contrast, some cancers induce autophagy and are dependent on autophagy for survival. Much in the way that autophagy promotes survival in starvation, cancers can use autophagy-mediated recycling to maintain mitochondrial function and energy homeostasis to meet the elevated metabolic demand of growth and proliferation. Thus, autophagy inhibition may be beneficial for cancer therapy. Moreover, tumors are more autophagy-dependent than normal tissues, suggesting that there is a therapeutic window. Despite these insights, many important unanswered questions remain about the exact mechanisms of autophagy-mediated cancer suppression and promotion, how relevant these observations are to humans, and whether the autophagy pathway can be modulated therapeutically in cancer. See all articles in this CCR Focus section, "Cell Death and Cancer Therapy." ©2015

  19. [Role of autophagy in TXNIP overexpression-induced apoptosis of INS-1 islet cells].

    Science.gov (United States)

    Wang, Jing; Wang, Jin; Wang, Juan-Juan; Zhang, Wei-Fang; Jiao, Xiang-Ying

    2017-08-25

    Thioredoxin (Trx) interacting protein (TXNIP) is a Trx-binding protein that inhibits the antioxidative function of Trx and is highly expressed in the serum and tissue samples from diabetes patients. This study was to explore whether TXNIP overexpression could cause INS-1 cell autophagy under normal glucose and lipid concentrations, and to analyze the role of autophagy in the apoptosis of INS-1 cells. The INS-1 cells cultured under normal conditions were divided into three groups: normal control, empty adenovirus vector (Ad-eGFP) and TXNIP overexpression (Ad-TXNIP-eGFP) groups. Forty-eight hours after transfection, the expression levels of TXNIP mRNA and protein were measured. Western blot was used to examine the protein expression levels of Beclin-1 and P62, as well as LC3-II/LC3-I ratio, which are associated with autophagy. IF/ICC was used to measure the autophagosome. In addition, the cleaved caspase-3/caspase-3 ratio, the apoptosis marker, was also measured, and the apoptotic rates were detected by flow cytometry (FCM). The results showed that the TXNIP mRNA and protein levels were significantly up-regulated in Ad-TXNIP-eGFP group, suggesting that TXNIP overexpression model was successfully established. In Ad-TXNIP-eGFP group, the protein levels of Beclin-1 and LC3-II/LC3-I ratio were increased, while the protein expression of P62 was decreased, compared with those in Ad-eGFP group. Red fluorescent intensity, representing autophagy level, was higher in Ad-TXNIP-eGFP group than that in Ad-eGFP group. These results suggested that TXNIP overexpression can significantly promote INS-1 cell autophagy. Meanwhile, cleaved caspase 3/caspase 3 ratio and the number of apoptotic cells were significantly increased in Ad-TXNIP-eGFP group. The inhibitor of autophagy, 3-MA, reduced TXNIP overexpression-induced apoptosis in INS-1 cells. Taken together, our data demonstrate that autophagy appears to be an important pathway in TXNIP overexpression-induced apoptosis in INS-1 cells.

  20. NOX4 mediates cytoprotective autophagy induced by the EGFR inhibitor erlotinib in head and neck cancer cells

    International Nuclear Information System (INIS)

    Sobhakumari, Arya; Schickling, Brandon M.; Love-Homan, Laurie; Raeburn, Ayanna; Fletcher, Elise V.M.; Case, Adam J.; Domann, Frederick E.; Miller, Francis J.

    2013-01-01

    Most head and neck squamous cell carcinomas (HNSCCs) overexpress epidermal growth factor receptor (EGFR) and EGFR inhibitors are routinely used in the treatment of HNSCC. However, many HNSCC tumors do not respond or become refractory to EGFR inhibitors. Autophagy, which is a stress-induced cellular self-degradation process, has been reported to reduce the efficacy of chemotherapy in various disease models. The purpose of this study is to determine if the efficacy of the EGFR inhibitor erlotinib is reduced by activation of autophagy via NOX4-mediated oxidative stress in HNSCC cells. Erlotinib induced the expression of the autophagy marker LC3B-II and autophagosome formation in FaDu and Cal-27 cells. Inhibition of autophagy by chloroquine and knockdown of autophagy pathway genes Beclin-1 and Atg5 sensitized both cell lines to erlotinib-induced cytotoxicity, suggesting that autophagy may serve as a protective mechanism. Treatment with catalase (CAT) and diphenylene iodonium (DPI) in the presence of erlotinib suppressed the increase in LC3B-II expression in FaDu and Cal-27 cells. Erlotinib increased NOX4 mRNA and protein expression by increasing its promoter activity and mRNA stability in FaDu cells. Knockdown of NOX4 using adenoviral siNOX4 partially suppressed erlotinib-induced LC3B-II expression, while overexpression of NOX4 increased expression of LC3B-II. These studies suggest that erlotinib may activate autophagy in HNSCC cells as a pro-survival mechanism, and NOX4 may play a role in mediating this effect. - Highlights: • Erlotinib increased LC3B-II and autophagosome formation in HNSCC cells. • Inhibition of autophagy sensitized HNSCC cells to erlotinib. • Erlotinib increased NOX4 promoter and 3′UTR luciferase activity. • Manipulating NOX4 decreases or increases autophagy

  1. Apoptosis and autophagy induced by pyropheophorbide-α methyl ester-mediated photodynamic therapy in human osteosarcoma MG-63 cells.

    Science.gov (United States)

    Huang, Qiu; Ou, Yun-Sheng; Tao, Yong; Yin, Hang; Tu, Ping-Hua

    2016-06-01

    Pyropheophorbide-α methyl ester (MPPa) was a second-generation photosensitizer with many potential applications. Here, we explored the impact of MPPa-mediated photodynamic therapy (MPPa-PDT) on the apoptosis and autophagy of human osteosarcoma (MG-63) cells as well as the relationships between apoptosis and autophagy of the cells, and investigated the related molecular mechanisms. We found that MPPa-PDT demonstrated the ability to inhibit MG-63 cell viability in an MPPa concentration- and light dose-dependent manner, and to induce apoptosis via the mitochondrial apoptosis pathway. Additionally, MPPa-PDT could also induce autophagy of MG-63 cell. Meanwhile, the ROS scavenger N-acetyl-L-cysteine (NAC) and the Jnk inhibitor SP600125 were found to inhibit the MPPa-PDT-induced autophagy, and NAC could also inhibit Jnk phosphorylation. Furthermore, pretreatment with the autophagy inhibitor 3-methyladenine or chloroquine showed the potential in reducing the apoptosis rate induced by MPPa-PDT in MG-63 cells. Our results indicated that the mitochondrial pathway was involved in MPPa-PDT-induced apoptosis of MG-63 cells. Meanwhile the ROS-Jnk signaling pathway was involved in MPPa-PDT-induced autophagy, which further promoted the apoptosis in MG-63 cells.

  2. 1-(2-Hydroxy-5-methylphenyl-3-phenyl-1,3-propanedione Induces G1 Cell Cycle Arrest and Autophagy in HeLa Cervical Cancer Cells

    Directory of Open Access Journals (Sweden)

    Jie-Heng Tsai

    2016-08-01

    Full Text Available The natural agent, 1-(2-hydroxy-5-methylphenyl-3-phenyl-1,3-propanedione (HMDB, has been reported to have growth inhibitory effects on several human cancer cells. However, the role of HMDB in cervical cancer remains unclear. Herein, we found that HMDB dose- and time-dependently inhibited growth of HeLa cervical cancer cells, accompanied with G1 cell cycle arrest. HMDB decreased protein expression of cyclins D1/D3/E and cyclin-dependent kinases (CDKs 2/4/6 and reciprocally increased mRNA and protein levels of CDK inhibitors (p15, p16, p21, and p27, thereby leading to the accumulation of hypophosphorylated retinoblastoma (Rb protein. HMDB also triggered the accumulation of acidic vesicles and formation of microtubule-associated protein-light chain 3 (LC3, followed by increased expression of LC3 and Beclin-1 and decreased expression of p62, suggesting that HMDB triggered autophagy in HeLa cells. Meanwhile, suppression of the expression of survivin and Bcl-2 implied that HMDB-induced autophagy is tightly linked to apoptosis. Exploring the action mechanism, HMDB induced autophagy via the modulation of AMP-activated protein kinase (AMPK and mTOR signaling pathway rather than the class III phosphatidylinositol 3-kinase pathway. These results suggest that HMDB inhibits HeLa cell growth by eliciting a G1 arrest through modulation of G1 cell cycle regulators and by concomitantly inducing autophagy through the mediation of AMPK-mTOR and Akt-mTOR pathways, and may be a promising antitumor agent against cervical cancer.

  3. Excess iodine promotes apoptosis of thyroid follicular epithelial cells by inducing autophagy suppression and is associated with Hashimoto thyroiditis disease.

    Science.gov (United States)

    Xu, Chengcheng; Wu, Fei; Mao, Chaoming; Wang, Xuefeng; Zheng, Tingting; Bu, Ling; Mou, Xiao; Zhou, Yuepeng; Yuan, Guoyue; Wang, Shengjun; Xiao, Yichuan

    2016-12-01

    The incidence of the autoimmune thyroid disease Hashimoto thyroiditis (HT) has increased in recent years, and increasing evidence supports the contribution of excess iodine intake to thyroid disease. In this study, we examined the status of autophagy and apoptosis in thyroid tissues obtained from patients with HT, and we determined the effects of excessive iodine on the autophagy and apoptosis of thyroid follicular cells (TFCs) in an attempt to elucidate the effects of excess iodine on HT development. Our results showed decreases in the autophagy-related protein LC3B-II, and increases in caspase-3 were observed in thyroid tissues from HT patients. Interestingly, the suppression of autophagy activity in TFCs was induced by excess iodine in vitro, and this process is mediated through transforming growth factor-β1 downregulation and activation of the Akt/mTOR signaling pathway. In addition, excess iodine induced autophagy suppression and enhanced reactive oxygen species (ROS) production and apoptosis of TFCs, which could be rescued by the activation of autophagy. Taken together, our results demonstrated that excess iodine contributed to autophagy suppression and apoptosis of TFCs, which could be important factors predisposing to increased risk of HT development. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Taxifolin synergizes Andrographolide-induced cell death by attenuation of autophagy and augmentation of caspase dependent and independent cell death in HeLa cells.

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    Mazen Alzaharna

    Full Text Available Andrographolide (Andro has emerged recently as a potential and effective anticancer agent with induction of apoptosis in some cancer cell lines while induction of G2/M arrest with weak apoptosis in others. Few studies have proved that Andro is also effective in combination therapy. The flavonoid Taxifolin (Taxi has showed anti-oxidant and antiproliferative effects against different cancer cells. Therefore, the present study investigated the cytotoxic effects of Andro alone or in combination with Taxi on HeLa cells. The combination of Andro with Taxi was synergistic at all tested concentrations and combination ratios. Andro alone induced caspase-dependent apoptosis which was enhanced by the combination with Taxi and attenuated partly by using Z-Vad-Fmk. Andro induced a protective reactive oxygen species (ROS-dependent autophagy which was attenuated by Taxi. The activation of p53 was involved in Andro-induced autophagy where the use of Taxi or pifithrin-α (PFT-α decreased it while the activation of JNK was involved in the cell death of HeLa cells but not in the induction of autophagy. The mitochondrial outer-membrane permeabilization (MOMP plays an important role in Andro-induced cell death in HeLa cells. Andro alone increased the MOMP which was further increased in the case of combination. This led to the increase in AIF and cytochrome c release from mitochondria which consequently increased caspase-dependent and independent cell death. In conclusion, Andro induced a protective autophagy in HeLa cells which was reduced by Taxi and the cell death was increased by increasing the MOMP and subsequently the caspase-dependent and independent cell death.

  5. Taxifolin synergizes Andrographolide-induced cell death by attenuation of autophagy and augmentation of caspase dependent and independent cell death in HeLa cells.

    Science.gov (United States)

    Alzaharna, Mazen; Alqouqa, Iyad; Cheung, Hon-Yeung

    2017-01-01

    Andrographolide (Andro) has emerged recently as a potential and effective anticancer agent with induction of apoptosis in some cancer cell lines while induction of G2/M arrest with weak apoptosis in others. Few studies have proved that Andro is also effective in combination therapy. The flavonoid Taxifolin (Taxi) has showed anti-oxidant and antiproliferative effects against different cancer cells. Therefore, the present study investigated the cytotoxic effects of Andro alone or in combination with Taxi on HeLa cells. The combination of Andro with Taxi was synergistic at all tested concentrations and combination ratios. Andro alone induced caspase-dependent apoptosis which was enhanced by the combination with Taxi and attenuated partly by using Z-Vad-Fmk. Andro induced a protective reactive oxygen species (ROS)-dependent autophagy which was attenuated by Taxi. The activation of p53 was involved in Andro-induced autophagy where the use of Taxi or pifithrin-α (PFT-α) decreased it while the activation of JNK was involved in the cell death of HeLa cells but not in the induction of autophagy. The mitochondrial outer-membrane permeabilization (MOMP) plays an important role in Andro-induced cell death in HeLa cells. Andro alone increased the MOMP which was further increased in the case of combination. This led to the increase in AIF and cytochrome c release from mitochondria which consequently increased caspase-dependent and independent cell death. In conclusion, Andro induced a protective autophagy in HeLa cells which was reduced by Taxi and the cell death was increased by increasing the MOMP and subsequently the caspase-dependent and independent cell death.

  6. Endoplasmic Reticulum Stress-Induced Autophagy Provides Cytoprotection from Chemical Hypoxia and Oxidant Injury and Ameliorates Renal Ischemia-Reperfusion Injury.

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    Bhavya B Chandrika

    Full Text Available We examined whether endoplasmic reticulum (ER stress-induced autophagy provides cytoprotection from renal tubular epithelial cell injury due to oxidants and chemical hypoxia in vitro, as well as from ischemia-reperfusion (IR injury in vivo. We demonstrate that the ER stress inducer tunicamycin triggers an unfolded protein response, upregulates ER chaperone Grp78, and activates the autophagy pathway in renal tubular epithelial cells in culture. Inhibition of ER stress-induced autophagy accelerated caspase-3 activation and cell death suggesting a pro-survival role of ER stress-induced autophagy. Compared to wild-type cells, autophagy-deficient MEFs subjected to ER stress had enhanced caspase-3 activation and cell death, a finding that further supports the cytoprotective role of ER stress-induced autophagy. Induction of autophagy by ER stress markedly afforded cytoprotection from oxidants H2O2 and tert-Butyl hydroperoxide and from chemical hypoxia induced by antimycin A. In contrast, inhibition of ER stress-induced autophagy or autophagy-deficient cells markedly enhanced cell death in response to oxidant injury and chemical hypoxia. In mouse kidney, similarly to renal epithelial cells in culture, tunicamycin triggered ER stress, markedly upregulated Grp78, and activated autophagy without impairing the autophagic flux. In addition, ER stress-induced autophagy markedly ameliorated renal IR injury as evident from significant improvement in renal function and histology. Inhibition of autophagy by chloroquine markedly increased renal IR injury. These studies highlight beneficial impact of ER stress-induced autophagy in renal ischemia-reperfusion injury both in vitro and in vivo.

  7. Green tea extract induces protective autophagy in A549 non-small lung cancer cell line

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    Magdalena Izdebska

    2015-12-01

    Full Text Available Background and objectives: For many decades, polyphenols, including green tea extract catechins, have been reported to exert multiple anti-tumor activities. However, to date the mechanisms of their action have not been completely elucidated. Thus, the aim of this study was to assess the effect of green tea extract on non-small lung cancer A549 cells. Material and methods: A549 cells following treatment with GTE were analyzed using the inverted light and fluorescence microscope. In order to evaluate cell sensitivity and cell death, the MTT assay and Tali image-based cytometer were used, respectively. Ultrastructural alterations were assessed using a transmission electron microscope.Results: The obtained data suggested that GTE, even at the highest dose employed (150 μM, was not toxic to A549 cells. Likewise, the treatment with GTE resulted in only a very small dose-dependent increase in the population of apoptotic cells. However, enhanced accumulation of vacuole-like structures in response to GTE was seen at the light and electron microscopic level. Furthermore, an increase in the acidic vesicular organelles and LC3-II puncta formation was observed under the fluorescence microscope, following GTE treatment. The analysis of the functional status of autophagy revealed that GTE-induced autophagy may provide self-protection against its own cytotoxicity, since we observed that the blockage of autophagy by bafilomycin A1 decreased the viability of A549 cells and potentiated necrotic cell death induction in response to GTE treatment.Conclusion: Collectively, our results revealed that A549 cells are insensitive to both low and high concentrations of the green tea extract, probably due to the induction of cytoprotective autophagy. These data suggest that a potential utility of GTE in lung cancer therapy may lie in its synergistic combinations with drugs or small molecules that target autophagy, rather than in monotherapy.

  8. Colza cell autophagy induced of high dose of industrial sewage sludge

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    Lasoued, Najla; Guenole Bilal, Issam; Rejeb, Saloua; Bilal, Essaid; Rejeb, Nejib

    2013-04-01

    This preliminary study is to evaluate the effects on colza of land application of industrial sludge containing heavy metals especially lead and chromium. We are interested in high doses spreading 100t/ha to better observe the phenomena of induced transformations on colza by the absorption of heavy metals. We used the technique for ultrastructural observation in a transmission electron microscope. The colza cells show a compaction and marginalization of nuclear chromatin, nuclear membrane and cytoplasmic convolution and condensation of cytoplasm. The kernel then fragments, each fragment are surrounded by a jacket. Some cytoplasmic and nuclear elements are released and are phagocytized by neighboring cells. We observed vacuolation of the cytoplasm and the formation of autophagic vesicles. The two main ways to cell death are apoptosis and autophagy. Apoptosis was not seen in plant yet. At the nucleus level cell death main characteristics are the nuclear blebbing and fragmentation. At the molecular level, caspases activity (VPE for plants, or metacaspases I and II), chromatin condensation, degradation of DNA detected by TUNEL assay and DNA laddering detected by comet test are the main events. Autophagy is the major degradation and recycling process in cells. Its aim is to address part of the cytoplasm or organelles to the proteasome. In macro-Autophagy a specific feature is the double membrane structure that we can see in electron microscopy. This membrane is known to fusion with the lysosome/vacuole where this is in process. As a rule, the vacuole grows more and more until no organelles remains. Small lytic vacuoles appear in increasing quantity also. Autophagosomes tend to be pushed against the membrane and wall of the cell. Sometime in the literature it was describe a permeabilization or a tonoplast disruption; this is the last stage called mega-autophagy. The stress generated by heavy metals in industrial sludge spreading, produces in colza cells programmed death

  9. Cardiac-Specific Overexpression of Catalase Attenuates Lipopolysaccharide-Induced Myocardial Contractile Dysfunction: Role of Autophagy

    OpenAIRE

    Turdi, Subat; Han, Xuefeng; Huff, Anna F.; Roe, Nathan D.; Hu, Nan; Gao, Feng; Ren, Jun

    2012-01-01

    Lipopolysaccharide (LPS) from Gram-negative bacteria is a major initiator of sepsis, leading to cardiovascular collapse. Accumulating evidence has indicated a role of reactive oxygen species (ROS) in cardiovascular complication in sepsis. This study was designed to examine the effect of cardiac-specific overexpression of catalase in LPS-induced cardiac contractile dysfunction and the underlying mechanism(s) with a focus on autophagy. Catalase transgenic and wild-type FVB mice were challenged ...

  10. Autophagy is induced by resistance exercise in young men but unfolded protein response is induced regardless of age.

    Science.gov (United States)

    Hentilä, Jaakko; Ahtiainen, Juha P; Paulsen, Gøran; Raastad, Truls; Häkkinen, Keijo; Mero, Antti A; Hulmi, Juha J

    2018-04-02

    Autophagy and unfolded protein response (UPR) appear to be important for skeletal muscle homeostasis and may be altered by exercise. Our aim was to investigate the effects of resistance exercise and training on indicators of UPR and autophagy in healthy untrained young men (n = 12, 27 ± 4 years) and older men (n = 8, 61 ± 6 years) as well as in resistance-trained individuals (n = 15, 25 ± 5 years). Indicators of autophagy and UPR were investigated from the muscle biopsies after a single resistance exercise bout and after 21 weeks of resistance training. Lipidated LC3II as an indicator of autophagosome content increased at 48 hours post resistance exercise (P resistance-training period (P resistance exercise in untrained young and older men (P resistance-training period regardless of age. UPR was unchanged within the first few hours after the resistance exercise bout regardless of the training status. Changes in autophagy and UPR ER indicators did not correlate with a resistance-training-induced increase in muscle strength and size. Autophagosome content is increased by resistance training in young previously untrained men, but this response may be blunted by aging. However, unfolded protein response is induced by an unaccustomed resistance exercise bout in a delayed manner regardless of age. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  11. Pharmacologic inhibition of autophagy sensitizes human acute leukemia Jurkat T cells to acacetin-induced apoptosis.

    Science.gov (United States)

    Lee, Ji Young; Jun, Do Youn; Kim, Ki Yun; Ha, Eun Ji; Woo, Mi Hee; Ko, Jee Youn; Yun, Young Ho; Oh, In-Seok; Kim, Young Ho

    2016-11-04

    Exposure of Jurkat T cell clone (J/Neo cells) to acacetin (5,7-dihydroxy-4'-methoxyflavone), which is present in barnyard millet [Echinochloa esculenta (A. Braun)] grains, resulted in cytotoxicity, accumulation of apoptotic sub-G1 cells, Bak activation, loss of mitochondrial membrane potential (Δψm), activation of caspase-9 and caspase-3, cleavage of poly (ADP-ribose) polymerase (PARP), and FITC-Annexin V-stainable phosphatidylserine exposure on the external surface of the cytoplasmic membrane without accompanying necrosis. These apoptotic responses were completely abrogated in Jurkat T cell clone (J/Bcl-xL) overexpressing Bcl-xL. Under these conditions, cellular autophagic responses, including suppression of the Akt-mTOR pathway and p62/SQSTM1 down-regulation, were detected both J/Neo and J/Bcl-xL cells; however, formation of acridine orange-stainable acidic vascular organelles, LC3-I/II conversion, and Beclin1 phosphorylation (Ser-15) were detected only in J/Neo cells. Correspondingly, concomitant treatment with the autophagy inhibitor (3-methyladenine or LY294002) appeared to enhance acacetin-induced apoptotic responses, such as Bak activation, Δψm loss, activation of caspae-9 and caspase-3, and apoptotic sub-G1 accumulation. This indicated that acacetin could induce apoptosis and cytoprotective autophagy in Jurkat T cells simultaneously. Together, these results demonstrate that acacetin induces not only apoptotic cell death via Bak activation, Δψm loss, and mitochondria-dependent activation of the caspase cascade, but also cytoprotective autophagy resulting from suppression of the Akt-mTOR pathway. Furthermore, pharmacologic inhibition of the autophagy pathway augments Bak activation and resultant mitochondrial damage-mediated apoptosis in Jurkat T cells.

  12. Moderate physical activity promotes basal hepatic autophagy in diet-induced obese mice.

    Science.gov (United States)

    Rosa-Caldwell, Megan E; Lee, David E; Brown, Jacob L; Brown, Lemuel A; Perry, Richard A; Greene, Elizabeth S; Carvallo Chaigneau, Francisco R; Washington, Tyrone A; Greene, Nicholas P

    2017-02-01

    Obesity is a known risk factor for the development of hepatic disease; obesity-induced fatty liver can lead to inflammation, steatosis, and cirrhosis and is associated with degeneration of the mitochondria. Lifestyle interventions such as physical activity may ameliorate this condition. The purpose of this study was to investigate regulation of mitochondrial and autophagy quality control in liver following Western diet-induced obesity and voluntary physical activity. Eight-week-old C57BL/6J mice were fed a Western diet (WD) or normal chow (NC, control) for 4 weeks; afterwards, groups were divided into voluntary wheel running (VWR) or sedentary (SED) conditions for an additional 4 weeks. WD-SED animals had a median histology score of 2, whereas WD-VWR was not different from NC groups (median score 1). There was no difference in mRNA of inflammatory markers Il6 and Tnfa in WD animals. WD animals had 50% lower mitochondrial content (COX IV and Cytochrome C proteins), 50% lower Pgc1a mRNA content, and reduced content of mitochondrial fusion and fission markers. Markers of autophagy were increased in VWR animals, regardless of obesity, as measured by 50% greater LC3-II/I ratio and 40% lower p62 protein content. BNIP3 protein content was 30% less in WD animals compared with NC animals, regardless of physical activity. Diet-induced obesity results in derangements in mitochondrial quality control that appear to occur prior to the onset of hepatic inflammation. Moderate physical activity appears to enhance basal autophagy in the liver; increased autophagy may provide protection from hepatic fat accumulation.

  13. Marrubium vulgare ethanolic extract induces proliferation block, apoptosis, and cytoprotective autophagy in cancer cells in vitro.

    Science.gov (United States)

    Paunovic, V; Kosic, M; Djordjevic, S; Zugic, A; Djalinac, N; Gasic, U; Trajkovic, V; Harhaji-Trajkovic, J

    2016-09-30

    Marrubium vulgare is a European medicinal plant with numerous beneficial effects on human health. The aim of the study was to isolate the plant ethanolic extract (MVE) and to investigate its anti-melanoma and anti-glioma effects. MVE was prepared by the modified pharmacopoeial percolation method and characterized by UHPLC-LTQ OrbiTrap MS. MVE dose-dependently reduced viability of melanoma (B16) and glioma (U251) cells, but not peripheral blood mononuclear cells. It arrested cell cycle in S+G2/M phase, which was associated with the activation of MAP kinase p38 and up-regulation of antiproliferative genes p53, p21 and p27. MVE induced oxidative stress, while antioxidants abrogated its antitumor effect. Furthermore, MVE induced mitochondrial depolarization, activation of caspase-9 and -3, Parp cleavage, phosphatidylserine exposure and DNA fragmentation. The mitochondrial apoptotic pathway was associated with the up-regulation of proapoptotic genes Pten, Bak1, Apaf1, and Puma and down-regulation of antiapoptotic genes survivin and Xiap. MVE also stimulated the expression of autophagy-related genes Atg5, Atg7, Atg12, Beclin-1, Gabarab and Sqstm1, as well as LC3-I conversion to the autophagosome associated LC3-II, while autophagy inhibitors exacerbated its cytotoxicity. Finally, the most abundant phenolic components of MVE, ferulic, p-hydroxybenzoic, caffeic and chlorogenic acids, did not exert a profound effect on viability of tumor cells, suggesting that other components individually or in concert are the mediators of the extracts' cytotoxicity. By demonstrating the ability of MVE to inhibit proliferation, induce apoptosis and cytoprotective autophagy, our results suggest that MVE, alone or combined with autophagy inhibitors, could be a good candidate for anti-melanoma and anti-glioma therapy.

  14. The role of kaempferol-induced autophagy on differentiation and mineralization of osteoblastic MC3T3-E1 cells.

    Science.gov (United States)

    Kim, In-Ryoung; Kim, Seong-Eon; Baek, Hyun-Su; Kim, Bok-Joo; Kim, Chul-Hoon; Chung, In-Kyo; Park, Bong-Soo; Shin, Sang-Hun

    2016-08-31

    Kaempferol, a kind of flavonol, has been reported to possess various osteogenic biological activities, such as inhibiting bone resorption of osteoclasts and promoting the differentiation and mineralization of preosteoblasts. However, the precise cellular mechanism of action of kaempferol in osteogenesis is elusive. Autophagy is a major intracellular degradation system, which plays an important role in cell growth, survival, differentiation and homeostasis in mammals. Recent studies showed that autophagy appeared to be involved in the degradation of osteoclasts, osteoblasts and osteocytes, potentially pointing to a new pathogenic mechanism of bone homeostasis and bone marrow disease. The potential correlation between autophagy, osteogenesis and flavonoids is unclear. The present study verified that kaempferol promoted osteogenic differentiation and mineralization and that it elevated osteogenic gene expression based on alkaline phosphatase (ALP) activity, alizarin red staining and quantitative PCR. And then we found that kaempferol induced autophagy by acridine orange (AO) and monodansylcadaverine (MDC) staining and autophagy-related protein expression. The correlation between kaempferol-induced autophagy and the osteogenic process was confirmed by the autophagy inhibitor 3-methyladenine (3-MA). Kaempferol promoted the proliferation, differentiation and mineralization of osteoblasts at a concentration of 10 μM. Kaempferol showed cytotoxic properties at concentrations above 50 μM. Concentrations above 10 μM decreased ALP activity, whereas those up to 10 μM increased ALP activity. Kaempferol at concentrations up to 10 μM also increased the expression of the osteoblast- activated factors RUNX-2, osterix, BMP-2 and collagen I according to RT-PCR analyses. 10 μM or less, the higher of the concentration and over time, kaempferol promoted the activity of osteoblasts. Kaempferol induced autophagy. It also increased the expression of the autophagy-related factors

  15. Cannabidiol protects liver from binge alcohol-induced steatosis by mechanisms including inhibition of oxidative stress and increase in autophagy.

    Science.gov (United States)

    Yang, Lili; Rozenfeld, Raphael; Wu, Defeng; Devi, Lakshmi A; Zhang, Zhenfeng; Cederbaum, Arthur

    2014-03-01

    Acute alcohol drinking induces steatosis, and effective prevention of steatosis can protect liver from progressive damage caused by alcohol. Increased oxidative stress has been reported as one mechanism underlying alcohol-induced steatosis. We evaluated whether cannabidiol, which has been reported to function as an antioxidant, can protect the liver from alcohol-generated oxidative stress-induced steatosis. Cannabidiol can prevent acute alcohol-induced liver steatosis in mice, possibly by preventing the increase in oxidative stress and the activation of the JNK MAPK pathway. Cannabidiol per se can increase autophagy both in CYP2E1-expressing HepG2 cells and in mouse liver. Importantly, cannabidiol can prevent the decrease in autophagy induced by alcohol. In conclusion, these results show that cannabidiol protects mouse liver from acute alcohol-induced steatosis through multiple mechanisms including attenuation of alcohol-mediated oxidative stress, prevention of JNK MAPK activation, and increasing autophagy. Published by Elsevier Inc.

  16. Mulberry anthocyanins improves thyroid cancer progression mainly by inducing apoptosis and autophagy cell death

    Directory of Open Access Journals (Sweden)

    Hou-Long Long

    2018-05-01

    Full Text Available Dietary anthocyanin compounds have multiple biological effects, including antioxidant, anti-inflammatory, and anti-atherosclerotic characteristics. The present study evaluated the anti-tumor capacity of mulberry anthocyanins (MA in thyroid cancer cells. Our data showed that MA suppressed SW1736 and HTh-7 cell proliferation in a time- and dose-dependent manner. Meanwhile, flow cytometry results indicated that MA significantly increased SW1736 and HTh-7 cell apoptosis. We additionally observed that SW1736 and HTh-7 cell autophagy was markedly enhanced after MA treatment. Importantly, anthocyanin-induced cell death was largely abolished by 3-methyladenine (3-MA or chloroquine diphosphate salt (CQ treatment, suggesting that MA-induced SW1736 and HTh-7 cell death was partially dependent on autophagy. In addition, activation of protein kinase B (Akt, mammalian target of rapamycin (mTOR, and ribosomal protein S6 (S6 were significantly suppressed by anthocyanin exposure. In summary, MA may serve as an adjunctive therapy for thyroid cancer patients through induction of apoptosis and autophagy-dependent cell death. Keywords: Mulberry anthocyanins, Thyroid cancer, Apoptosis, Autophagic death

  17. A synthetic ion transporter that disrupts autophagy and induces apoptosis by perturbing cellular chloride concentrations

    Science.gov (United States)

    Busschaert, Nathalie; Park, Seong-Hyun; Baek, Kyung-Hwa; Choi, Yoon Pyo; Park, Jinhong; Howe, Ethan N. W.; Hiscock, Jennifer R.; Karagiannidis, Louise E.; Marques, Igor; Félix, Vítor; Namkung, Wan; Sessler, Jonathan L.; Gale, Philip A.; Shin, Injae

    2017-07-01

    Perturbations in cellular chloride concentrations can affect cellular pH and autophagy and lead to the onset of apoptosis. With this in mind, synthetic ion transporters have been used to disturb cellular ion homeostasis and thereby induce cell death; however, it is not clear whether synthetic ion transporters can also be used to disrupt autophagy. Here, we show that squaramide-based ion transporters enhance the transport of chloride anions in liposomal models and promote sodium chloride influx into the cytosol. Liposomal and cellular transport activity of the squaramides is shown to correlate with cell death activity, which is attributed to caspase-dependent apoptosis. One ion transporter was also shown to cause additional changes in lysosomal pH, which leads to impairment of lysosomal enzyme activity and disruption of autophagic processes. This disruption is independent of the initiation of apoptosis by the ion transporter. This study provides the first experimental evidence that synthetic ion transporters can disrupt both autophagy and induce apoptosis.

  18. Cathepsin D inhibits oxidative stress-induced cell death via activation of autophagy in cancer cells.

    Science.gov (United States)

    Hah, Young-Sool; Noh, Hae Sook; Ha, Ji Hye; Ahn, Jin Sook; Hahm, Jong Ryeal; Cho, Hee Young; Kim, Deok Ryong

    2012-10-28

    Cathepsin D (CatD), a lysosomal aspartic protease, plays an essential role in tumor progression and apoptosis. However, the function of CatD in cell death is not yet fully understood. In this study, we identified CatD as one of up-regulated proteins in human malignant glioblastoma M059J cells that lack the catalytic subunit of DNA-PK compared with its isogenic M059K cells with normal DNA-PK activity. M059J cells were relatively more resistant to genotoxic stress than M059K cells. Overexpression of wild-type CatD but not catalytically inactive mutant CatD (D295N) inhibited H(2)O(2)-induced cell death in HeLa cells. Furthermore, knockdown of CatD expression abolished anti-apoptotic effect by CatD in the presence of H(2)O(2). Interestingly, high expression of CatD in HeLa cells significantly activated autophagy: increase of acidic autophagic vacuoles, LC3-II formation, and GFP-LC3 puncta. These results suggest that CatD can function as an anti-apoptotic mediator by inducing autophagy under cellular stress. In conclusion, inhibition of autophagy could be a novel strategy for the adjuvant chemotherapy of CatD-expressing cancers. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  19. Unsaturated fatty acids protect trophoblast cells from saturated fatty acid-induced autophagy defects.

    Science.gov (United States)

    Hong, Ye-Ji; Ahn, Hyo-Ju; Shin, Jongdae; Lee, Joon H; Kim, Jin-Hoi; Park, Hwan-Woo; Lee, Sung Ki

    2018-02-01

    Dysregulated serum fatty acids are associated with a lipotoxic placental environment, which contributes to increased pregnancy complications via altered trophoblast invasion. However, the role of saturated and unsaturated fatty acids in trophoblastic autophagy has yet to be explored. Here, we demonstrated that prolonged exposure of saturated fatty acids interferes with the invasiveness of human extravillous trophoblasts. Saturated fatty acids (but not unsaturated fatty acids) inhibited the fusion of autophagosomes and lysosomes, resulting in the formation of intracellular protein aggregates. Furthermore, when the trophoblast cells were exposed to saturated fatty acids, unsaturated fatty acids counteracted the effects of saturated fatty acids by increasing degradation of autophagic vacuoles. Saturated fatty acids reduced the levels of the matrix metalloproteinases (MMP)-2 and MMP-9, while unsaturated fatty acids maintained their levels. In conclusion, saturated fatty acids induced decreased trophoblast invasion, of which autophagy dysfunction plays a major role. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Autophagy in brain ischemia

    Directory of Open Access Journals (Sweden)

    Alicja Kost

    2011-08-01

    Full Text Available Autophagy is an intracellular process of macromolecule and organelle degradation, which plays an important role both in maintaining homeostasis and in responding to various harmful stimuli. Recent studies clearly indicate upregulation of autophagy in neurons challenged with brain ischemia. In this paper we present biosynthesis of autophagosomes as well as the role and molecular mechanisms of basal and induced neuronal autophagy. We have also reviewed recently published papers concerning the potential role of autophagy in brain ischemia. Results of both in vivo and in vitro experimental studies indicate that signaling pathways related to autophagy might become a target of new neuroprotective strategies.

  1. Antioxidant catalase rescues against high fat diet-induced cardiac dysfunction via an IKKβ-AMPK-dependent regulation of autophagy.

    Science.gov (United States)

    Liang, Lei; Shou, Xi-Ling; Zhao, Hai-Kang; Ren, Gu-Qun; Wang, Jian-Bang; Wang, Xi-Hui; Ai, Wen-Ting; Maris, Jackie R; Hueckstaedt, Lindsay K; Ma, Ai-Qun; Zhang, Yingmei

    2015-02-01

    Autophagy, a conservative degradation process for long-lived and damaged proteins, participates in a variety of biological processes including obesity. However, the precise mechanism of action behind obesity-induced changes in autophagy still remains elusive. This study was designed to examine the role of the antioxidant catalase in high fat diet-induced changes in cardiac geometry and function as well as the underlying mechanism of action involved with a focus on autophagy. Wild-type (WT) and transgenic mice with cardiac overexpression of catalase were fed low or high fat diet for 20 weeks prior to assessment of myocardial geometry and function. High fat diet intake triggered obesity, hyperinsulinemia, and hypertriglyceridemia, the effects of which were unaffected by catalase transgene. Myocardial geometry and function were compromised with fat diet intake as manifested by cardiac hypertrophy, enlarged left ventricular end systolic and diastolic diameters, fractional shortening, cardiomyocyte contractile capacity and intracellular Ca²⁺ mishandling, the effects of which were ameliorated by catalase. High fat diet intake promoted reactive oxygen species production and suppressed autophagy in the heart, the effects of which were attenuated by catalase. High fat diet intake dampened phosphorylation of inhibitor kappa B kinase β(IKKβ), AMP-activated protein kinase (AMPK) and tuberous sclerosis 2 (TSC2) while promoting phosphorylation of mTOR, the effects of which were ablated by catalase. In vitro study revealed that palmitic acid compromised cardiomyocyte autophagy and contractile function in a manner reminiscent of fat diet intake, the effect of which was significantly alleviated by inhibition of IKKβ, activation of AMPK and induction of autophagy. Taken together, our data revealed that the antioxidant catalase counteracts against high fat diet-induced cardiac geometric and functional anomalies possibly via an IKKβ-AMPK-dependent restoration of myocardial

  2. Synergistic effect of natural compounds on the fatty acid-induced autophagy of activated hepatic stellate cells.

    Science.gov (United States)

    Lee, Kuan-Wei; Thiyagarajan, Varadharajan; Sie, Huei-Wun; Cheng, Ming-Fan; Tsai, May-Jywan; Chia, Yi-Chen; Weng, Ching-Feng

    2014-09-01

    Autophagy, a lysosomal pathway to maintain cellular homeostasis, is mediated via the mammalian target of rapamycin (mTOR)-dependent pathways. Hepatic stellate cells (HSCs), previously termed fat- or vitamin A-storing cells, can transdifferentiate into myofibroblast-like cells and are the most relevant cell type for overproduction of extracellular matrix (ECM) and development of liver fibrosis during injury. However, the role of autophagy in fat metabolism of HSCs remains unclear. This study investigates the regulatory effect of natural compounds on fatty acid-induced autophagy pathways of nonchemical-induced HSC (NHSC) and thioacetamide-induced HSC. Oleic acid (OA) and palmitic acid (PA) have shown a significant effect on cell proliferation with oil red O staining and Western blot confirming that OA and PA induce fat storage ability and autophagy protein expression in NHSC. Natural compounds rutin, curcumin, antroquinonol and benzyl cinnamate treatment have shown no effect on the autophagy protein expression. Nevertheless, cells pretreated with OA and PA then treated with rutin, curcumin, antroquinonol and benzyl cinnamate could significantly induce the light chain I/II (LC3 I/II) protein expression. In mTOR-dependent pathway, the PI3K-Class I, Akt, and p-mTOR proteins were decreased with PA treatment. However, there were no significant changes in PI3K-Class III and Beclin-1 protein expressions found to imply that this autophagy is unrelated to the mTOR-independent pathway. Taken together, the present study unveils rutin and curcumin as a possible effective stimulation for fatty acid-induced autophagy via mTOR-dependent pathways in NHSC. We further suggest the benefits of these natural compounds for alleviating liver fibrosis. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. YM155 down-regulates survivin and XIAP, modulates autophagy and induces autophagy-dependent DNA damage in breast cancer cells

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    Cheng, S M; Chang, Y C; Liu, C Y; Lee, J Y C; Chan, H H; Kuo, C W; Lin, K Y; Tsai, S L; Chen, S H; Li, C F; Leung, E; Kanwar, J R; Huang, C C; Chang, J Y; Cheung, C H A

    2015-01-01

    BACKGROUND AND PURPOSE The aim of this study was to determine the potency and molecular mechanism of action of YM155, a first-in-class survivin inhibitor that is currently under phase I/II clinical investigations, in various drug-resistant breast cancers including the oestrogen receptor positive (ER+) tamoxifen-resistant breast cancer and the caspase-3-deficient breast cancer. EXPERIMENTAL APPROACH The potency of YM155 in SK-BR-3, MDA-MB-231, MCF7 and its tamoxifen-resistant sublines, TamR6, TamR7, TamR8, TamC3 and TamC6, were determined by MTT assay. Western blot analysis, flow cytometric analysis, reverse transcription-PCR, fluorescent microscopy and comet assay were used to determine the molecular mechanism of action of YM155 in different breast cancer cell lines. KEY RESULTS YM155 was equally potent towards the parental ER+/caspase-3-deficient MCF7 breast cancer cells and its tamoxifen-resistant sublines in vitro. The ER−/HER2+ SK-BR-3 breast cancer cells and the triple-negative/caspase-3-expressing metastatic aggressive MDA-MB-231 breast cancer cells were also sensitive to YM155 with IC50 values in the low nanomolar range. Targeting survivin by YM155 modulated autophagy, induced autophagy-dependent caspase-7 activation and autophagy-dependent DNA damage in breast cancer cells. Interestingly, YM155 also induced XIAP degradation and the degradation of XIAP might play an important role in YM155-induced autophagy in breast cancer cells. CONCLUSIONS AND IMPLICATIONS YM155 is a potent survivin inhibitor that has potential for the management of various breast cancer subtypes regardless of the expression of ER, HER2 and caspase-3. Importantly, this study provides new insights into YM155's molecular mechanism of action and therapeutic potential in the treatment of tamoxifen-resistant breast cancer. PMID:25220225

  4. SIRT6 reduces macrophage foam cell formation by inducing autophagy and cholesterol efflux under ox-LDL condition.

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    He, Jiangping; Zhang, Guangya; Pang, Qi; Yu, Cong; Xiong, Jie; Zhu, Jing; Chen, Fengling

    2017-05-01

    SIRT6 is a pivotal regulator of lipid metabolism. It is also closely connected to cardiovascular diseases, which are the main cause of death in diabetic patients. We observed a decrease in the expression of SIRT6 and key autophagy effectors (ATG5, LC3B, and LAMP1) in ox-LDL-induced foam cells, a special form of lipid-laden macrophages. In these cells, SIRT6 WT but not SIRT6 H133Y overexpression markedly reduced foam cell formation, as shown by Oil Red O staining, while inducing autophagy flux, as determined by both mRFP-GFP-LC3 labeling and transmission electron microscopy. Silencing the key autophagy initiation gene ATG5, reversed the autophagy-promoting effect of SIRT6 in ox-LDL-treated THP1 cells, as evidenced by an increase in foam cells. Cholesterol efflux assays indicated that SIRT6 overexpression in foam cells promoted cholesterol efflux, increased the levels of ABCA1 and ABCG1, and reduced miR-33 levels. By transfecting miR-33 into cells overexpressing SIRT6, we observed that reduced foam cell formation and autophagy flux induction were largely reversed. These data imply that SIRT6 plays an essential role in protecting against atherosclerosis by reducing foam cell formation through an autophagy-dependent pathway. © 2017 Federation of European Biochemical Societies.

  5. Scutellarin Increases Cisplatin-Induced Apoptosis and Autophagy to Overcome Cisplatin Resistance in Non-small Cell Lung Cancer via ERK/p53 and c-met/AKT Signaling Pathways

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    Chao-Yue Sun

    2018-02-01

    Full Text Available Cisplatin, as the first-line anti-tumor agent, is widely used for treatment of a variety of malignancies including non-small cell lung cancer (NSCLC. However, the acquired resistance has been a major obstacle for the clinical application. Scutellarin is a active flavone extracted from Erigeron breviscapus Hand-Mazz that has been shown to exhibit anticancer activities on various types of tumors. Here, we reported that scutellarin was capable of sensitizing A549/DDP cells to cisplatin by enhancing apoptosis and autophagy. Mechanistic analyses indicated that cisplatin-induced caspase-3-dependent apoptosis was elevated in the presence of scutellarin through activating extracellular signal-regulated kinases (ERK-mediated p53 pathway. Furthermore, scutellarin also promoted cisplatin-induced cytotoxic autophagy, downregulated expression of p-AKT and c-met. Deficiency of c-met reduced p-AKT level, and inhibition of p-AKT or c-met improved autophagy in A549/DDP cells. Interestingly, loss of autophagy attenuated the synergism of this combination. In vivo, the co-treatment of cisplatin and scutellarin notably reduced the tumor size when compared with cisplatin treatment alone. Notably, scutellarin significantly reduced the toxicity generated by cisplatin in tumor-bearing mice. This study identifies the unique role of scutellarin in reversing cisplatin resistance through apoptosis and autophagy, and suggests that combined cisplatin and scutellarin might be a novel therapeutic strategy for patients with NSCLC.

  6. Nrf2 reduces levels of phosphorylated tau protein by inducing autophagy adaptor protein NDP52

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    Jo, Chulman; Gundemir, Soner; Pritchard, Susanne; Jin, Youngnam N.; Rahman, Irfan; Johnson, Gail V. W.

    2014-03-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a pivotal transcription factor in the defence against oxidative stress. Here we provide evidence that activation of the Nrf2 pathway reduces the levels of phosphorylated tau by induction of an autophagy adaptor protein NDP52 (also known as CALCOCO2) in neurons. The expression of NDP52, which we show has three antioxidant response elements (AREs) in its promoter region, is strongly induced by Nrf2, and its overexpression facilitates clearance of phosphorylated tau in the presence of an autophagy stimulator. In Nrf2-knockout mice, phosphorylated and sarkosyl-insoluble tau accumulates in the brains concurrent with decreased levels of NDP52. Moreover, NDP52 associates with phosphorylated tau from brain cortical samples of Alzheimer disease cases, and the amount of phosphorylated tau in sarkosyl-insoluble fractions is inversely proportional to that of NDP52. These results suggest that NDP52 plays a key role in autophagy-mediated degradation of phosphorylated tau in vivo.

  7. Salinomycin induces autophagy in colon and breast cancer cells with concomitant generation of reactive oxygen species.

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    Berlinda Verdoodt

    Full Text Available BACKGROUND: Salinomycin is a polyether ionophore antibiotic that has recently been shown to induce cell death in human cancer cells displaying multiple mechanisms of drug resistance. The underlying mechanisms leading to cell death after salinomycin treatment have not been well characterized. We therefore investigated the role of salinomycin in caspase dependent and independent cell death in colon cancer (SW480, SW620, RKO and breast cancer cell lines (MCF-7, T47D, MDA-MB-453. METHODOLOGY/PRINCIPAL FINDINGS: We detected features of apoptosis in all cell lines tested, but the executor caspases 3 and 7 were only strongly activated in RKO and MDA-MB-453 cells. MCF-7 and SW620 cells instead presented features of autophagy such as cytoplasmic vacuolization and LC3 processing. Caspase proficient cell lines activated autophagy at lower salinomycin concentrations and before the onset of caspase activation. Salinomycin also led to the formation of reactive oxygen species (ROS eliciting JNK activation and induction of the transcription factor JUN. Salinomycin mediated cell death could be partially inhibited by the free radical scavenger N-acetyl-cysteine, implicating ROS formation in the mechanism of salinomycin toxicity. CONCLUSIONS: Our data indicate that, in addition to its previously reported induction of caspase dependent apoptosis, the initiation of autophagy is an important and early effect of salinomycin in tumor cells.

  8. Induced pluripotent stem cell-based modeling of neurodegenerative diseases: a focus on autophagy.

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    Jungverdorben, Johannes; Till, Andreas; Brüstle, Oliver

    2017-07-01

    The advent of cell reprogramming has enabled the generation of induced pluripotent stem cells (iPSCs) from patient skin fibroblasts or blood cells and their subsequent differentiation into tissue-specific cells, including neurons and glia. This approach can be used to recapitulate disease-specific phenotypes in classical cell culture paradigms and thus represents an invaluable asset for disease modeling and drug validation in the framework of personalized medicine. The autophagy pathway is a ubiquitous eukaryotic degradation and recycling system, which relies on lysosomal degradation of unwanted and potentially cytotoxic components. The relevance of autophagy in the pathogenesis of neurodegenerative diseases is underlined by the observation that disease-linked genetic variants of susceptibility factors frequently result in dysregulation of autophagic-lysosomal pathways. In particular, disrupted autophagy is implied in the accumulation of potentially neurotoxic products such as protein aggregates and their precursors and defective turnover of dysfunctional mitochondria. Here, we review the current state of iPSC-based assessment of autophagic dysfunction in the context of neurodegenerative disease modeling. The collected data show that iPSC technology is capable to reveal even subtle alterations in subcellular homeostatic processes, which form the molecular basis for disease manifestation.

  9. Bone marrow mesenchymal stem cells protect against n-hexane-induced neuropathy through beclin 1-independent inhibition of autophagy.

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    Hao, Jie; Li, Shuangyue; Shi, Xiaoxia; Qian, Zhiqiang; Sun, Yijie; Wang, Dunjia; Zhou, Xueying; Qu, Hongxin; Hu, Shuhai; Zuo, Enjun; Zhang, Cong; Hou, Liyan; Wang, Qingshan; Piao, Fengyuan

    2018-03-14

    Chronic exposure to n-hexane, a widely used organic solvent in industry, induces central-peripheral neuropathy, which is mediated by its active metabolite, 2,5-hexanedione (HD). We recently reported that transplantation of bone marrow-mesenchymal stem cells (BMSC) significantly ameliorated HD-induced neuronal damage and motor deficits in rats. However, the mechanisms remain unclear. Here, we reported that inhibition of HD-induced autophagy contributed to BMSC-afforded protection. BMSC transplantation significantly reduced the levels of microtubule-associated protein 1 light chain 3-II (LC3-II) and the degradation of sequestosome-1 (p62) in the spinal cord and sciatic nerve of HD-intoxicated rats. Downregulation of autophagy by BMSC was also confirmed in VSC4.1 cells exposed to HD. Moreover, inhibition of autophagy by PIK III mitigated the neurotoxic effects of HD and, meanwhile, abolished BMSC-afforded neuroprotection. Furthermore, we found that BMSC failed to interfere with Beclin 1, but promoted activation of mammalian target of rapamycin (mTOR). Unc-like kinse 1 (ULK1) was further recognized as the downstream target of mTOR responsible for BMSC-mediated inhibition of autophagy. Altogether, BMSC transplantation potently ameliorated HD-induced autophagy through beclin 1-independent activation of mTOR pathway, providing a novel insight for the therapeutic effects of BMSC against n-hexane and other environmental toxicants-induced neurotoxicity.

  10. Chloroquine enhances cobalt chloride-induced leukemic cell differentiation via the suppression of autophagy at the late phase.

    Science.gov (United States)

    Yan, Zhao-Wen; Hou, Jia-Kai; He, Wei; Fan, Li; Huang, Ying

    2013-01-18

    We previously reported that moderate hypoxia and hypoxia-mimetic agents including cobalt chloride (CoCl(2)) induce differentiation of human acute myeloid leukemia (AML) cells through hypoxia-inducible factor-1 α (HIF-1 α), which interacts with and enhances transcriptional activity of CCAAT-enhancer binding factor alpha and Runx1/AML1, two important transcriptional factors for hematopoietic cell differentiation. Here, we show that autophagy inhibitor chloroquine (CQ) increases HIF-1 α accumulation, thus potentiating CoCl(2)-induced growth arrest and differentiation of leukemic cells. Furthermore, the increased effect of CQ on differentiation induction is dependent of the inhibition of autophagosome maturation and degradation, since this sensitization could be mimicked by the suppression of expression of both lysosome-associated membrane proteins 1 and 2 (LAMP1 and LAMP2). These findings not only provide the evidence that CQ is a sensitizer for CoCl(2)-induced differentiation of leukemic cells but also possibly propose the new therapeutic strategy for differentiation induction of AML. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Dihydrocapsaicin (DHC), a saturated structural analog of capsaicin, induces autophagy in human cancer cells in a catalase-regulated manner.

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    Oh, Seon Hee; Kim, Young Soon; Lim, Sung Chul; Hou, Yi Feng; Chang, In Youb; You, Ho Jin

    2008-11-01

    Although capsaicin, a pungent component of red pepper, is known to induce apoptosis in several types of cancer cells, the mechanisms underlying capsaicin-induced cytotoxicity are unclear. Here, we showed that dihydrocapsaicin (DHC), an analog of capsaicin, is a potential inducer of autophagy. DHC was more cytotoxic than capsaicin in HCT116, MCF-7 and WI38 cell lines. Capsaicin and DHC did not affect the sub-G(1) apoptotic peak, but induced G(0)/G(1) arrest in HCT116 and MCF-7 cells. DHC caused the artificial autophagosome marker GFP-LC3 to redistribute and upregulated expression of autophagy-related proteins. Blocking of autophagy by 3-methyladenine (3MA) as well as siRNA Atg5 induced a high level of caspase-3 activation. Although pretreatment with zVAD completely inhibited caspase-3 activation by 3MA, it did not prevent cell death. DHC-induced autophagy was enhanced by zVAD pretreatment, as shown by increased accumulation of LC3-II protein. DHC attenuated basal ROS levels through catalase induction; this effect was enhanced by antioxidants, which increased both LC3-II expression and caspase-3 activation. The catalase inhibitor 3-amino-1,2,4-triazole (3AT) abrogated DHC-induced expression of LC3-II, overexpression of the catalase gene increased expression of LC3-II protein, and knockdown decreased it. Additionally, DHC-induced autophagy was independent of p53 status. Collectively, DHC activates autophagy in a p53-independent manner and that may contribute to cytotoxicity of DHC.

  12. Platycodin D induced apoptosis and autophagy in PC-12 cells through mitochondrial dysfunction pathway

    Science.gov (United States)

    Zeng, Chuan-Chuan; Zhang, Cheng; Yao, Jun-Hua; Lai, Shang-Hai; Han, Bing-Jie; Li, Wei; Tang, Bing; Wan, Dan; Liu, Yun-Jun

    2016-11-01

    In this article, the in vitro cytotoxicity of platycodin D was evaluated in human PC-12, SGC-7901, BEL-7402, HeLa and A549 cancer cell lines. PC-12 cells were sensitive to platycodin D treatment, with an IC50 value of 13.5 ± 1.2 μM. Morphological and comet assays showed that platycodin D effectively induced apoptosis in PC-12 cells. Platycodin D increased the levels of reactive oxygen species (ROS) and induced a decrease in mitochondrial membrane potential. Platycodin D induced cell cycle arrest at the G0/G1 phase in the PC-12 cell line. Platycodin D can induce autophagy. In addition, platycodin D can down-regulate the expression of Bcl-2 and Bcl-x, and up-regulate the levels of Bid protein in the PC-12 cells. The results demonstrated that platycodin D induced PC-12 cell apoptosis through a ROS-mediated mitochondrial dysfunction pathway.

  13. AMPK is required for PM2.5-induced autophagy in human lung epithelial A549 cells

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    Wang, Yahong; Lin, Ziying; Huang, Haili; He, Huijuan; Yang, Lawei; Chen, Ting; Yang, Teng; Ren, Nina; Jiang, Yun; Xu, Wenya; Kamp, David W; Liu, Tie; Liu, Gang

    2015-01-01

    The aim is to investigate the molecular mechanisms underlying the PM2.5-induced autophagy in human lung cancer epithelial cells (A549). The effects of the PM2.5 on morphological and biochemical markers of autophagy in A549 were analyzed by electron microscopy, GFP-LC3 puncta was observed by confocal fluorescence microscope. The effects of phosphorylation of AMPK, mTOR, AKT, ERK, JNK, and p53 on LC3II in A549 were observed following PM2.5 exposure; the role of autophagy in PM2.5-induced apoptosis was examined using 3-methyladenine and rapamycin. PM2.5 induced morphological and biochemical markers of autophagy in A549. Phosphorylation of AMPK and dephosphorylation of mTOR were observed following PM2.5 treatment, and AMPK inhibitor blocked LC3B-II expression. In addition, we demonstrated that PM2.5-induced autophagy confers a pro-survival role in host defense. PMID:25784975

  14. Importance of Autophagy in Mediating Human Immunodeficiency Virus (HIV) and Morphine-Induced Metabolic Dysfunction and Inflammation in Human Astrocytes.

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    Rodriguez, Myosotys; Lapierre, Jessica; Ojha, Chet Raj; Estrada-Bueno, Hary; Dever, Seth M; Gewirtz, David A; Kashanchi, Fatah; El-Hage, Nazira

    2017-07-28

    Under physiological conditions, the function of astrocytes in providing brain metabolic support is compromised under pathophysiological conditions caused by human immunodeficiency virus (HIV) and opioids. Herein, we examined the role of autophagy, a lysosomal degradation pathway important for cellular homeostasis and survival, as a potential regulatory mechanism during pathophysiological conditions in primary human astrocytes. Blocking autophagy with small interfering RNA (siRNA) targeting BECN1 , but not the Autophagy-related 5 ( ATG5 ) gene, caused a significant decrease in HIV and morphine-induced intracellular calcium release. On the contrary, inducing autophagy pharmacologically with rapamycin further enhanced calcium release and significantly reverted HIV and morphine-decreased glutamate uptake. Furthermore, siBeclin1 caused an increase in HIV-induced nitric oxide (NO) release, while viral-induced NO in astrocytes exposed to rapamycin was decreased. HIV replication was significantly attenuated in astrocytes transfected with siRNA while significantly induced in astrocytes exposed to rapamycin. Silencing with siBeclin1, but not siATG5, caused a significant decrease in HIV and morphine-induced interleukin (IL)-8 and tumor necrosis factor alpha (TNF-α) release, while secretion of IL-8 was significantly induced with rapamycin. Mechanistically, the effects of siBeclin1 in decreasing HIV-induced calcium release, viral replication, and viral-induced cytokine secretion were associated with a decrease in activation of the nuclear factor kappa B (NF-κB) pathway.

  15. Mouse Sirt3 promotes autophagy in AngII-induced myocardial hypertrophy through the deacetylation of FoxO1.

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    Li, Jingyuan; Chen, Tongshuai; Xiao, Ming; Li, Na; Wang, Shujian; Su, Hongyan; Guo, Xiaobin; Liu, Hui; Yan, Fangying; Yang, Yi; Zhang, Yun; Bu, Peili

    2016-12-27

    Sirt3, a mitochondrial NAD+-dependent histone deacetylase, is the only member proven to promote longevity in mammalian Sirtuin family. The processed short form of Sirt3 has been demonstrated to target many mediators of energy metabolism and mitochondrial stress adaptive program. Autophagy serves as a dynamic recycling mechanism and provides energy or metabolic substrates. Among the mechanisms triggered by cardiac stress, opinions vary as to whether autophagy is a protective or detrimental response. Here, by inducing the Sirt3-knockout mice to myocardial hypertrophy with chronic angiotensin II infusion for four weeks, we determined the role of Sirt3 in myocardial hypertrophy and autophagy. In this study, the Sirt3-knockout mice developed deteriorated cardiac function and impaired autophagy compared to wild-type mice. What's more, the overexpression of Sirt3 by lentivirus transfection attenuated cardiomyocytes hypertrophy by promoting autophagy. We further demonstrated that Sirt3 could bind to FoxO1 and activate its deacetylation. Sequentially, deacetylated FoxO1 translocates to the nucleus where it facilitates downstream E3 ubiquitin ligases such as Muscle RING Finger 1 (MuRF1) and muscle atrophy F-box (MAFbx, Atrogin1). Altogether, these results revealed that Sirt3 activation is essential to improve autophagy flux by reducing the acetylation modification on FoxO1, which in turn alleviates myocardial hypertrophy.

  16. AMPK activation restores ischemic post‑conditioning cardioprotection in STZ‑induced type 1 diabetic rats: Role of autophagy.

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    Zhou, Bin; Leng, Yan; Lei, Shao-Qing; Xia, Zhong-Yuan

    2017-09-01

    Although the mechanism remains unclear, ischemic post‑conditioning (IPO) is a promising approach to combat myocardial ischemia reperfusion (IR) injury; however, it has been proven ineffective in diabetes. The present study aimed to identify whether hyperglycemia‑induced AMP‑activated protein kinase (AMPK) inhibition contributes to the ineffectiveness of IPO via autophagy attenuation in diabetic hearts. Diabetic and non‑diabetic rats were subjected to myocardial IR and/or IPO with/without treatment with the AMPK activator A‑769662 and/or autophagy inhibitor 3‑methyladenine (3‑MA). Rat cardiomyocyte H9c2 cells were pretreated with A‑769662 and/or 3‑MA, and subjected to hypoxia reoxygenation (HR) or hypoxia post‑conditioning (HPO). The degree of injury to the myocardium/cells, oxidative stress, AMPK/mammalian target of rapamycin (mTOR) signaling and autophagy status were analyzed. In diabetic rats the myocardial infarct size, and creatine kinase‑MB and malondialdehyde release, were increased compared with non‑diabetic rats, concomitant with increased cardiac dysfunction and decreased cardiac superoxide dismutase activity, AMPK phosphorylation and autophagy following IR. IPO attenuated myocardial infarct size, increased AMPK phosphorylation and enhanced autophagy in non‑diabetic animals. A‑769662 (6.0 mg/kg) restored IPO cardioprotection in diabetic rats. In vitro, HPO combined with A‑769662 decreased HR injury in H9c2 cells exposed to high glucose, as evidenced by decreased lactic dehydrogenase expression and oxidative stress, accompanied by increased cell viability and autophagy. The A‑769662‑mediated restoration of IPO/HPO cardioprotection was completely reversed by treatment with the autophagy inhibitor 3‑MA. In conclusion, AMPK inhibition, by decreasing autophagy, may be a mechanism through which diabetic hearts are rendered unresponsive to IPO cardioprotection.

  17. shRNA-mediated AMBRA1 knockdown reduces the cisplatin-induced autophagy and sensitizes ovarian cancer cells to cisplatin.

    Science.gov (United States)

    Li, Xiaoyan; Zhang, Lijuan; Yu, Lili; Wei, Wei; Lin, Xueyan; Hou, Xiaoman; Tian, Yongjie

    2016-02-01

    Recent research has revealed a role for Ambra1, an autophagy-related gene-related (ATG) protein, in the autophagic pro-survival response, and Ambra1 has been shown to regulate Beclin1 and Beclin1-dependent autophagy in embryonic stem cells and cancer cells. However, whether Ambra1 plays an important role in the autophagy pathway in ovarian cancer cells is unknown. In this study, we hypothesized that Ambra1 is an important regulator of autophagy and apoptosis in ovarian cancer cells. We firstly confirmed autophagic activity in ovarian cancer OVCAR-3 cells which were treated with cisplatin by assessing endogenous microtubule-associated protein 1 light chain 3 (LC3) localization and the presence of autophagosomes and LC3 protein levels in OVCAR-3 cells. Cell apoptosis and viability were measured by annexin-V and PI staining and MTT assays. We then knocked down Ambra1 expression with transfection with the plasmid expressing the small hairpin RNA (shRNA) targeting AMBRA1, then re-evaluated autophagy in the OVCAR-3 cells subject to cisplatin treatment, and re-determined the sensitivity of OVCAR-3 cells to cisplatin. Results demonstrated that cisplatin treatment induced autophagy in OVCAR-3 cells in association with Ambra1 upregulation in the ovarian cancer cells. When Ambra1 expression was reduced by shRNA, the ovarian cancer cells were more sensitive to cisplatin. In conclusion, Ambra1 is a crucial regulator of autophagy and apoptosis in ovarian cancer cells subject to cisplatin to maintain the balance between autophagy and apoptosis. And the Ambra1-targeting inhibition might be an effective method to sensitize ovarian cancer cells to chemotherapy.

  18. Xanthones from the Leaves of Garcinia cowa Induce Cell Cycle Arrest, Apoptosis, and Autophagy in Cancer Cells

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    Zhengxiang Xia

    2015-06-01

    Full Text Available Two new xanthones, cowaxanthones G (1 and H (2, and 23 known analogues were isolated from an acetone extract of the leaves of Garcinia cowa. The isolated compounds were evaluated for cytotoxicity against three cancer cell lines and immortalized HL7702 normal liver cells, whereby compounds 1, 5, 8, and 15–17 exhibited significant cytotoxicity. Cell cycle analysis using flow cytometry showed that 5 induced cell cycle arrest at the S phase in a dose-dependent manner, 1 and 16 at the G2/M phase, and 17 at the G1 phase, while 16 and 17 induced apoptosis. Moreover, autophagy analysis by GFP-LC3 puncta formation and western blotting suggested that 17 induced autophagy. Taken together, our results suggest that these xanthones possess anticancer activities targeting cell cycle, apoptosis, and autophagy signaling pathways.

  19. Photodynamic N-TiO2 Nanoparticle Treatment Induces Controlled ROS-mediated Autophagy and Terminal Differentiation of Leukemia Cells.

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    Moosavi, Mohammad Amin; Sharifi, Maryam; Ghafary, Soroush Moasses; Mohammadalipour, Zahra; Khataee, Alireza; Rahmati, Marveh; Hajjaran, Sadaf; Łos, Marek J; Klonisch, Thomas; Ghavami, Saeid

    2016-10-04

    In this study, we used nitrogen-doped titanium dioxide (N-TiO 2 ) NPs in conjugation with visible light, and show that both reactive oxygen species (ROS) and autophagy are induced by this novel NP-based photodynamic therapy (PDT) system. While well-dispersed N-TiO 2 NPs (≤100 μg/ml) were inert, their photo-activation with visible light led to ROS-mediated autophagy in leukemia K562 cells and normal peripheral lymphocytes, and this increased in parallel with increasing NP concentrations and light doses. At a constant light energy (12 J/cm 2 ), increasing N-TiO 2 NP concentrations increased ROS levels to trigger autophagy-dependent megakaryocytic terminal differentiation in K562 cells. By contrast, an ROS challenge induced by high N-TiO 2 NP concentrations led to autophagy-associated apoptotic cell death. Using chemical autophagy inhibitors (3-methyladenine and Bafilomycin A1), we confirmed that autophagy is required for both terminal differentiation and apoptosis induced by photo-activated N-TiO 2 . Pre-incubation of leukemic cells with ROS scavengers muted the effect of N-TiO 2 NP-based PDT on cell fate, highlighting the upstream role of ROS in our system. In summary, PDT using N-TiO 2 NPs provides an effective method of priming autophagy by ROS induction. The capability of photo-activated N-TiO 2 NPs in obtaining desirable cellular outcomes represents a novel therapeutic strategy of cancer cells.

  20. Ischemic conditioning by short periods of reperfusion attenuates renal ischemia/reperfusion induced apoptosis and autophagy in the rat

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    Chien Chiang-Ting

    2009-02-01

    Full Text Available Abstract Prolonged ischemia amplified iscehemia/reperfusion (IR induced renal apoptosis and autophagy. We hypothesize that ischemic conditioning (IC by a briefly intermittent reperfusion during a prolonged ischemic phase may ameliorate IR induced renal dysfunction. We evaluated the antioxidant/oxidant mechanism, autophagy and apoptosis in the uninephrectomized Wistar rats subjected to sham control, 4 stages of 15-min IC (I15 × 4, 2 stages of 30-min IC (I30 × 2, and total 60-min ischema (I60 in the kidney followed by 4 or 24 hours of reperfusion. By use of ATP assay, monitoring O2-. amounts, autophagy and apoptosis analysis of rat kidneys, I60 followed by 4 hours of reperfusion decreased renal ATP and enhanced reactive oxygen species (ROS level and proapoptotic and autophagic mechanisms, including enhanced Bax/Bcl-2 ratio, cytochrome C release, active caspase 3, poly-(ADP-ribose-polymerase (PARP degradation fragments, microtubule-associated protein light chain 3 (LC3 and Beclin-1 expression and subsequently tubular apoptosis and autophagy associated with elevated blood urea nitrogen and creatinine level. I30 × 2, not I15 × 4 decreased ROS production and cytochrome C release, increased Manganese superoxide dismutase (MnSOD, Copper-Zn superoxide dismutase (CuZnSOD and catalase expression and provided a more efficient protection than I60 against IR induced tubular apoptosis and autophagy and blood urea nitrogen and creatinine level. We conclude that 60-min renal ischemia enhanced renal tubular oxidative stress, proapoptosis and autophagy in the rat kidneys. Two stages of 30-min ischemia with 3-min reperfusion significantly preserved renal ATP content, increased antioxidant defense mechanisms and decreased ischemia/reperfusion enhanced renal tubular oxidative stress, cytosolic cytochrome C release, proapoptosis and autophagy in rat kidneys.

  1. Remifentanil induces autophagy and prevents hydrogen peroxide-induced apoptosis in Cos-7 cells.

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    Yoon, Ji-Young; Baek, Chul-Woo; Woo, Mi-Na; Kim, Eun-Jung; Yoon, Ji-Uk; Park, Chang-Hoon

    2016-09-01

    This study investigated the effect of remifentanil pretreatment on Cos-7 cells exposed to oxidative stress, and the influence of remifentanil on intracellular autophagy and apoptotic cell death. Cells were divided into 4 groups: (1) Control: non-pretreated cells were incubated in normoxia (5% CO 2 , 21% O 2 , and 74% N 2 ). (2) H 2 O 2 : non-pretreated cells were exposed to H 2 O 2 for 24 h. (3) RPC+H 2 O 2 : cells pretreated with remifentanil were exposed to H 2 O 2 for 24 h. (4) 3-MA+RPC+H 2 O 2 : cells pretreated with 3-Methyladenine (3-MA) and remifentanil were exposed to H 2 O 2 for 24 h. We determined the cell viability of each group using an MTT assay. Hoechst staining and FACS analysis of Cos-7 cells were performed to observe the effect of remifentanil on apoptosis. Autophagy activation was determined by fluorescence microscopy, MDC staining, and AO staining. The expression of autophagy-related proteins was observed using western blotting. Remifentanil pretreatment increased the viability of Cos-7 cells exposed to oxidative stress. Hoechst staining and FACS analysis revealed that oxidative stress-dependent apoptosis was suppressed by the pretreatment. Additionally, fluorescence microscopy showed that remifentanil pretreatment led to autophagy-induction in Cos-7 cells, and the expression of autophagy-related proteins was increased in the RPC+H 2 O 2 group. The study showed that remifentanil pretreatment stimulated autophagy and increased viability in an oxidative stress model of Cos-7 cells. Therefore, we suggest that apoptosis was activated upon oxidative stress, and remifentanil preconditioning increased the survival rate of the cells by activating autophagy.

  2. Autophagy activation is involved in 3,4-methylenedioxymethamphetamine ('ecstasy'--induced neurotoxicity in cultured cortical neurons.

    Directory of Open Access Journals (Sweden)

    I-Hsun Li

    Full Text Available Autophagic (type II cell death, characterized by the massive accumulation of autophagic vacuoles in the cytoplasm of cells, has been suggested to play pathogenetic roles in cerebral ischemia, brain trauma, and neurodegenerative disorders. 3,4-Methylenedioxymethamphetamine (MDMA or ecstasy is an illicit drug causing long-term neurotoxicity in the brain. Apoptotic (type I and necrotic (type III cell death have been implicated in MDMA-induced neurotoxicity, while the role of autophagy in MDMA-elicited neurotoxicity has not been investigated. The present study aimed to evaluate the occurrence and contribution of autophagy to neurotoxicity in cultured rat cortical neurons challenged with MDMA. Autophagy activation was monitored by expression of microtubule-associated protein 1 light chain 3 (LC3; an autophagic marker using immunofluorescence and western blot analysis. Here, we demonstrate that MDMA exposure induced monodansylcadaverine (MDC- and LC3B-densely stained autophagosome formation and increased conversion of LC3B-I to LC3B-II, coinciding with the neurodegenerative phase of MDMA challenge. Autophagy inhibitor 3-methyladenine (3-MA pretreatment significantly attenuated MDMA-induced autophagosome accumulation, LC3B-II expression, and ameliorated MDMA-triggered neurite damage and neuronal death. In contrast, enhanced autophagy flux by rapamycin or impaired autophagosome clearance by bafilomycin A1 led to more autophagosome accumulation in neurons and aggravated neurite degeneration, indicating that excessive autophagosome accumulation contributes to MDMA-induced neurotoxicity. Furthermore, MDMA induced phosphorylation of AMP-activated protein kinase (AMPK and its downstream unc-51-like kinase 1 (ULK1, suggesting the AMPK/ULK1 signaling pathway might be involved in MDMA-induced autophagy activation.

  3. Autophagy controls BCG-induced trained immunity and the response to intravesical BCG therapy for bladder cancer.

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    Kathrin Buffen

    2014-10-01

    Full Text Available The anti-tuberculosis-vaccine Bacillus Calmette-Guérin (BCG is the most widely used vaccine in the world. In addition to its effects against tuberculosis, BCG vaccination also induces non-specific beneficial effects against certain forms of malignancy and against infections with unrelated pathogens. It has been recently proposed that the non-specific effects of BCG are mediated through epigenetic reprogramming of monocytes, a process called trained immunity. In the present study we demonstrate that autophagy contributes to trained immunity induced by BCG. Pharmacologic inhibition of autophagy blocked trained immunity induced in vitro by stimuli such as β-glucans or BCG. Single nucleotide polymorphisms (SNPs in the autophagy genes ATG2B (rs3759601 and ATG5 (rs2245214 influenced both the in vitro and in vivo training effect of BCG upon restimulation with unrelated bacterial or fungal stimuli. Furthermore, pharmacologic or genetic inhibition of autophagy blocked epigenetic reprogramming of monocytes at the level of H3K4 trimethylation. Finally, we demonstrate that rs3759601 in ATG2B correlates with progression and recurrence of bladder cancer after BCG intravesical instillation therapy. These findings identify a key role of autophagy for the nonspecific protective effects of BCG.

  4. Interleukin-6: a bone marrow stromal cell paracrine signal that induces neuroendocrine differentiation and modulates autophagy in bone metastatic PCa cells.

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    Delk, Nikki A; Farach-Carson, Mary C

    2012-04-01

    Autophagy reallocates nutrients and clears normal cells of damaged proteins and organelles. In the context of metastatic disease, invading cancer cells hijack autophagic processes to survive and adapt in the host microenvironment. We sought to understand how autophagy is regulated in the metastatic niche for prostate cancer (PCa) cells where bone marrow stromal cell (BMSC) paracrine signaling induces PCa neuroendocrine differentiation (NED). In PCa, this transdifferentiation of metastatic PCa cells to neuronal-like cells correlates with advanced disease. Because autophagy provides a survival advantage for cancer cells and promotes cell differentiation, we hypothesized that autophagy mediates PCa NED in the bone. Thus, we determined the ability of paracrine factors in conditioned media (CM) from two separate BMSC subtypes, HS5 and HS27a, to induce autophagy in C4-2 and C4-2B bone metastatic PCa cells by characterizing the autophagy marker, LC3. Unlike HS27a CM, HS5 CM induced LC3 accumulation in PCa cells, suggesting autophagy was induced and indicating that HS5 and HS27a secrete a different milieu of paracrine factors that influence PCa autophagy. We identified interleukin-6 (IL-6), a cytokine more highly expressed in HS5 cells than in HS27a cells, as a paracrine factor that regulates PCa autophagy. Pharmacological inhibition of STAT3 activity did not attenuate LC3 accumulation, implying that IL-6 regulates NED and autophagy through different pathways. Finally, chloroquine inhibition of autophagic flux blocked PCa NED; hence autophagic flux maintains NED. Our studies imply that autophagy is cytoprotective for PCa cells in the bone, thus targeting autophagy is a potential therapeutic strategy.

  5. Wounding of Arabidopsis leaves induces indole-3-carbinol-dependent autophagy in roots of Arabidopsis thaliana.

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    Katz, Ella; Chamovitz, Daniel A

    2017-09-01

    In cruciferous plants insect attack or physical damage induce the synthesis of the glucosinolate breakdown product indole-3-carbinol, which plays a key role in the defense against attackers. Indole-3-carbinol also affects plant growth and development, acting as an auxin antagonist by binding to the TIR1 auxin receptor. Other potential functions of indole-3-carbinol and the underlying mechanisms in plant biology are unknown. Here we show that an indole-3-carbinol-dependent signal induces specific autophagy in root cells. Leaf treatment with exogenous indole-3-carbinol or leaf-wounding induced autophagy and inhibited auxin response in the root. This induction is lost in glucosinolate-defective mutants, indicating that the effect of indole-3-carbinol is transported in the plants. Thus, indole-3-carbinol is not only a defensive metabolite that repels insects, but is also involved in long-distance communication regulating growth and development in plants. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  6. Effect of autophagy on cisplatin-induced bladder cancer cell apoptosis.

    Science.gov (United States)

    Fan, Zhiqiang; Huangfu, Xuejun; Liu, Zhonghua

    2017-03-01

    To investigate the effects of autophagy in cisplatin-induced apoptosis of bladder cancer cells. Bladder cancer cell T24 was regarded as cell model. The transmission electron microscope was employed to detect autophagic vacuoles and the fluorescence microscope to detect the fluorescence accumulation profile of vectors for green fluorescent protein and microtubule associated protein 1 light chain 3 fusion protein (GFP-LC3). Protein immunoblotting was applied to detect the accumulation of LC3-II, thus detecting whether cisplatin could induce the bladder cancer T24 cell autophagy. Moreover, protein immunoblotting was ultilized to detect the autophagic relative signal pathway mammal target of rapamycin (mTOR) and the variation of ribosomal protein S6 kinase (P70S6K) with relative molecular mass 70,000 in downstream as well as the cleavage of apoptosis marker protein poly ADP-ribose polymerase (PARP). Afterwards, with the utilization of 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS), the viability changes in cisplatin-induced bladder cancer cells under the condition of autophagy promoting the presentation or absence of rapamycin were observed. Moreover, RNA interference was also adopted in this experiment to knockdown the LC3 expression. Compared with the control group, the electron microscope revealed that cisplatin was able to induce plenty of autophagic vacuoles in bladder cancer cells. CFP-LC3 aggregation was viewed by the fluorescence microscope, showing a significant higher in cisplatin group than control group. The results of LC3 detected by protein immunoblotting indicated that the LC3-II content in cisplatin group was significantly enhanced with the prolongation of time and increase of cisplatin concentration. Especially, at the concentration of 50 and 100 μmol/L for 48 hours with cisplatin treatment, the gray value of LC3-II/Actin (%) increased 30 and 44, respectively. Cisplatin treatment inhibited

  7. Treatment-Induced Autophagy Associated with Tumor Dormancy and Relapse

    Science.gov (United States)

    2015-07-01

    frequently other steroid hormone receptors such as androgen receptor (102,259–275). Most of these chemicals also targeted growth factors and their...ATG12-/- MMC tumor cells where we might also expect that ADR treatment will results in sustained growth arrest/dormancy. ADR chemotherapy induces...Sevilla, Avda Manuel Siurot sn, 41013 Sevilla, Spain, 7Department of Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine

  8. Isoaaptamine Induces T-47D Cells Apoptosis and Autophagy via Oxidative Stress

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    Chih-Fung Wu

    2018-01-01

    Full Text Available Aaptos is a genus of marine sponge which belongs to Suberitidae and is distributed in tropical and subtropical oceans. Bioactivity-guided fractionation of Aaptos sp. methanolic extract resulted in the isolation of aaptamine, demethyloxyaaptamine, and isoaaptamine. The cytotoxic activity of the isolated compounds was evaluated revealing that isoaaptamine exhibited potent cytotoxic activity against breast cancer T-47D cells. In a concentration-dependent manner, isoaaptamine inhibited the growth of T-47D cells as indicated by short-(MTT and long-term (colony formation anti-proliferative assays. The cytotoxic effect of isoaaptamine was mediated through apoptosis as indicated by DNA ladder formation, caspase-7 activation, XIAP inhibition and PARP cleavage. Transmission electron microscopy and flow cytometric analysis using acridine orange dye indicated that isoaaptamine treatment could induce T-47D cells autophagy. Immunoblot assays demonstrated that isoaaptamine treatment significantly activated autophagy marker proteins such as type II LC-3. In addition, isoaaptamine treatment enhanced the activation of DNA damage (γH2AX and ER stress-related proteins (IRE1 α and BiP. Moreover, the use of isoaaptamine resulted in a significant increase in the generation of reactive oxygen species (ROS as well as in the disruption of mitochondrial membrane potential (MMP. The pretreatment of T-47D cells with an ROS scavenger, N-acetyl-l-cysteine (NAC, attenuated the apoptosis and MMP disruption induced by isoaaptamine up to 90%, and these effects were mediated by the disruption of nuclear factor erythroid 2-related factor 2 (Nrf 2/p62 pathway. Taken together, these findings suggested that the cytotoxic effect of isoaaptamine is associated with the induction of apoptosis and autophagy through oxidative stress. Our data indicated that isoaaptamine represents an interesting drug lead in the war against breast cancer.

  9. ZnPP reduces autophagy and induces apoptosis, thus aggravating liver ischemia/reperfusion injury in vitro.

    Science.gov (United States)

    Wang, Yun; Xiong, Xuanxuan; Guo, Hao; Wu, Mingbo; Li, Xiangcheng; Hu, Yuanchao; Xie, Guangwei; Shen, Jian; Tian, Qingzhong

    2014-12-01

    There is growing evidence indicating that autophagy plays a protective role in liver ischemia/reperfusion (IR) injury. Heme oxygenase-1 (HO-1) can also prevent liver IR injury by limiting inflammation and inducing an anti-apoptotic response. Autophagy also plays a crucial role in liver IR injury. The aim of the present study was to investigate the role of HO-1 in liver IR injury and the association between HO-1, autophagy and apoptotic pathways. IR simulation was performed using buffalo rat liver (BRL) cells, and HO-1 activity was either induced by hemin (HIR group) or inhibited by zinc protoporphyrin (ZnPP) (ZIR group). In the HIR and ZIR group, the expression of HO-1 and autophagy-related genes [light chain 3-Ⅱ (LC3-Ⅱ)] was assessed by RT-qPCR and the protein expression of caspases, autophagy-related genes and genes associated with apoptotic pathways (Bax) was detected by western blot anlaysis. The results of RT-PCR revealed the genetically decreased expression of HO-1 and autophagy-related genes in the ZIR group. Similar results were obtained by western blot analysis and immunofluorescence. An ultrastructural analysis revealed a lower number of autophagosomes in the ZIR group; in the HIR group, the number of autophagosomes was increased. The expression of Bax and cytosolic cytochrome c was increased, while that of Bcl-2 was decreased following treatment of the cells with ZnPP prior to IR simulation; the oppostie occurred in the HIR group. Cleaved caspase-3, caspase-9 and poly(ADP-ribose) polymerase (PARP) protein were activated in the IR and ZIR groups. The disruption of mitochondrial membrane potential was also observed in the ZIR group. In general, the downregulation of HO-1 reduced autophagy and activated the mitochondrial apoptotic pathway.

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

    Science.gov (United States)

    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

  11. Qianlie Xiaozheng Decoction Induces Autophagy in Human Prostate Cancer Cells via Inhibition of the Akt/mTOR Pathway

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    Yuehua Xu

    2018-04-01

    Full Text Available Qianlie Xiaozheng decoction (QLXZD, a traditional Chinese medicinal formula, has been used clinically to treat advanced prostate cancer (PCa for more than 10 years. However, experimental evidence supporting its efficacy is lacking. Here, we investigated the anticancer properties and molecular mechanism of QLXZD in vitro in a human PCa cell line (PC3 and in vivo using PC3 xenografts in nude mice. We confirmed the antineoplastic activity of QLXZD by analyzing cell viability and tumor volume growth, which decreased significantly compared to that of the controls. Autophagy following QLXZD treatment was detected morphologically using transmission electron microscopy and was confirmed by measuring the expression of autophagy markers (LC3-II and p62 using fluorescence analysis, flow cytometry, and western blotting. Increasing autophagic flux induced by QLXZD was monitored via pmCherry-GFP-LC3 fluorescence analysis. QLXZD-induced autophagic cell death was alleviated by the autophagy inhibitors, 3-methyl adenine and hydroxychloroquine. We evaluated the total expression and phosphorylation levels of proteins involved in the Akt/mTOR pathway regulating autophagy. Phosphorylation of Akt, mTOR, and p70S6K, but not total protein levels, decreased following treatment. This is the first study to demonstrate the autophagy-related mechanistic pathways utilized during QLXZD-mediated antitumor activity both in vitro and in vivo. These findings support the clinical use of QLXZD for PCa treatment.

  12. Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: A potential role for reducing UVB light-induced retinal damage

    International Nuclear Information System (INIS)

    Li, Chao-Peng; Yao, Jin; Tao, Zhi-Fu; Li, Xiu-Miao; Jiang, Qin; Yan, Biao

    2013-01-01

    Highlights: •UVB irradiation induces RPE autophagy. •EGCG treatment represses UVB-mediated autophagy. •EGCG regulates UVB-mediated autophagy through mTOR signaling pathway. •EGCG sensitizes RPE cells to UVB-induced damage in an autophagy-dependent manner. -- Abstract: Autophagy is an intracellular catabolic process involved in protein and organelle degradation via the lysosomal pathway that has been linked in the pathogenesis of age-related macular degeneration (AMD). UVB irradiation-mediated degeneration of the macular retinal pigment epithelial (RPE) cells is an important hallmark of AMD, which is along with the change in RPE autophagy. Thus, pharmacological manipulation of RPE autophagy may offer an alternative therapeutic target in AMD. Here, we found that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, plays a regulatory role in UVB irradiation-induced autophagy in RPE cells. UVB irradiation results in a marked increase in the amount of LC3-II protein in a dose-dependent manner. EGCG administration leads to a significant reduction in the formation of LC3-II and autophagosomes. mTOR signaling activation is required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation is significantly impaired by rapamycin administration. Moreover, EGCG significantly alleviates the toxic effects of UVB irradiation on RPE cells in an autophagy-dependent manner. Collectively, our study reveals a novel role of EGCG in RPE autophagy. EGCG may be exploited as a potential therapeutic reagent for the treatment of pathological conditions associated with abnormal autophagy

  13. Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: A potential role for reducing UVB light-induced retinal damage

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chao-Peng; Yao, Jin; Tao, Zhi-Fu; Li, Xiu-Miao; Jiang, Qin, E-mail: jqin710@vip.sina.com; Yan, Biao, E-mail: yanbiao1982@hotmail.com

    2013-09-06

    Highlights: •UVB irradiation induces RPE autophagy. •EGCG treatment represses UVB-mediated autophagy. •EGCG regulates UVB-mediated autophagy through mTOR signaling pathway. •EGCG sensitizes RPE cells to UVB-induced damage in an autophagy-dependent manner. -- Abstract: Autophagy is an intracellular catabolic process involved in protein and organelle degradation via the lysosomal pathway that has been linked in the pathogenesis of age-related macular degeneration (AMD). UVB irradiation-mediated degeneration of the macular retinal pigment epithelial (RPE) cells is an important hallmark of AMD, which is along with the change in RPE autophagy. Thus, pharmacological manipulation of RPE autophagy may offer an alternative therapeutic target in AMD. Here, we found that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, plays a regulatory role in UVB irradiation-induced autophagy in RPE cells. UVB irradiation results in a marked increase in the amount of LC3-II protein in a dose-dependent manner. EGCG administration leads to a significant reduction in the formation of LC3-II and autophagosomes. mTOR signaling activation is required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation is significantly impaired by rapamycin administration. Moreover, EGCG significantly alleviates the toxic effects of UVB irradiation on RPE cells in an autophagy-dependent manner. Collectively, our study reveals a novel role of EGCG in RPE autophagy. EGCG may be exploited as a potential therapeutic reagent for the treatment of pathological conditions associated with abnormal autophagy.

  14. Shear Stress Induces Phenotypic Modulation of Vascular Smooth Muscle Cells via AMPK/mTOR/ULK1-Mediated Autophagy.

    Science.gov (United States)

    Sun, Liqian; Zhao, Manman; Liu, Aihua; Lv, Ming; Zhang, Jingbo; Li, Youxiang; Yang, Xinjian; Wu, Zhongxue

    2018-03-01

    Phenotypic modulation of vascular smooth muscle cells (VSMCs) is involved in the pathophysiological processes of the intracranial aneurysms (IAs). Although shear stress has been implicated in the proliferation, migration, and phenotypic conversion of VSMCs, the molecular mechanisms underlying these events are currently unknown. In this study, we investigated whether shear stress(SS)-induced VSMC phenotypic modulation was mediated by autophagy involved in adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/Unc-51-like kinase 1 (ULK1) pathway. The results show that shear stress could inhibit the expression of key VSMC contractile genes and induce pro-inflammatory/matrix-remodeling genes levels, contributing to VSMCs phenotypic switching from a contractile to a synthetic phenotype. More importantly, Shear stress also markedly increased the levels of the autophagy marker microtubule-associated protein light chain 3-II (LC3II), Beclin-1, and p62 degradation. The autophagy inhibitor 3-methyladenine (3-MA) significantly blocked shear-induced phenotypic modulation of VSMCs. To further explore the molecular mechanism involved in shear-induced autophagy, we found that shear stress could activate AMPK/mTOR/ULK1 signaling pathway in VSMCs. Compound C, a pharmacological inhibitor of AMPK, significantly reduced the levels of p-AMPK and p-ULK, enhanced p-mTOR level, and finally decreased LC3II and Beclin-1 level, which suggested that activated AMPK/mTOR/ULK1 signaling was related to shear-mediated autophagy. These results indicate that shear stress promotes VSMC phenotypic modulation through the induction of autophagy involved in activating the AMPK/mTOR/ULK1 pathway.

  15. Hypoxia Induces Autophagy through Translational Up-Regulation of Lysosomal Proteins in Human Colon Cancer Cells.

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    Ming-Chih Lai

    Full Text Available Hypoxia occurs in a wide variety of physiological and pathological conditions, including tumorigenesis. Tumor cells have to adapt to hypoxia by altering their gene expression and protein synthesis. Here, we showed that hypoxia inhibits translation through activation of PERK and inactivation of mTOR in human colon cancer HCT116 cells. Prolonged hypoxia (1% O2, 16 h dramatically inhibits general translation in HCT116 cells, yet selected mRNAs remain efficiently translated under such a condition. Using microarray analysis of polysome- associated mRNAs, we identified a large number of hypoxia-regulated genes at the translational level. Efficiently translated mRNAs during hypoxia were validated by polysome profiling and quantitative real-time RT-PCR. Pathway enrichment analysis showed that many of the up-regulated genes are involved in lysosome, glycan and lipid metabolism, antigen presentation, cell adhesion, and remodeling of the extracellular matrix and cytoskeleton. The majority of down-regulated genes are involved in apoptosis, ubiquitin-mediated proteolysis, and oxidative phosphorylation. Further investigation showed that hypoxia induces lysosomal autophagy and mitochondrial dysfunction through translational regulation in HCT116 cells. The abundance of several translation factors and the mTOR kinase activity are involved in hypoxia-induced mitochondrial autophagy in HCT116 cells. Our studies highlight the importance of translational regulation for tumor cell adaptation to hypoxia.

  16. Aspalathin Reverts Doxorubicin-Induced Cardiotoxicity through Increased Autophagy and Decreased Expression of p53/mTOR/p62 Signaling

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    Rabia Johnson

    2017-09-01

    Full Text Available Doxorubicin (Dox is an effective chemotherapeutic agent used in the treatment of various cancers. Its clinical use is often limited due to its potentially fatal cardiotoxic side effect. Increasing evidence indicates that tumour protein p53 (p53, adenosine monophosphate-activated protein kinase (AMPK, nucleoporin p62 (p62, and the mammalian target of rapamycin (mTOR are critical mediators of Dox-induced apoptosis, and subsequent dysregulation of autophagy. Aspalathin, a polyphenolic dihydrochalcone C-glucoside has been shown to activate AMPK while decreasing the expression of p53. However, the role that aspalathin could play in the inhibition of Dox-induced cardiotoxicity through increased autophagy flux remained unexplored. H9c2 cardiomyocytes and Caov-3 ovarian cancer cells were cultured in Dulbecco’s Modified Eagle’s medium and treated with or without Dox for five days. Thereafter, cells exposed to 0.2 µM Dox were co-treated with either 20 µM Dexrazozane (Dexra or 0.2 µM aspalathin (ASP daily for 5 days. Results obtained showed that ASP mediates its cytoprotective effect in a p53-dependent manner, by increasing the Bcl-2/Bax ratio and decreasing apoptosis. The latter effect was diminished through ASP-induced activation of autophagy-related genes (Atgs with an associated decrease in p62 through induction of AMPK and Fox01. Furthermore, we showed that ASP was able to potentiate this effect without decreasing the anti-cancer efficacy of Dox, as could be observed in Caov-3 ovarian cancer cells. Taken together, the data presented in this study provides a credible mechanism by which ASP co-treatment could protect the myocardium from Dox-induced cardiotoxicity.

  17. N-Acetyl Cysteine Protects against Methamphetamine-Induced Dopaminergic Neurodegeneration via Modulation of Redox Status and Autophagy in Dopaminergic Cells

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    Prashanth Chandramani Shivalingappa

    2012-01-01

    Full Text Available Methamphetamine- (MA- induced neurotoxicity is associated with mitochondrial dysfunction and enhanced oxidative stress. Our previous study demonstrated that MA induces autophagy in a dopaminergic neuronal cell model (N27 cells. The cellular mechanisms underlying MA-induced autophagy and apoptosis remain poorly characterized. In the present study we sought to investigate the importance of GSH redox status in MA-induced neurotoxicity using a thiol antioxidant, N-acetylcysteine (NAC. Morphological and biochemical analysis revealed that MA-induced autophagy in N27 dopaminergic cells was associated with pronounced depletion of GSH levels. Moreover, pretreatment with NAC reduced MA-induced GSH depletion and autophagy, while depletion of GSH using L-buthionine sulfoximine (L-BSO enhanced autophagy. Furthermore, treatment with NAC significantly attenuated MA-induced apoptotic cell death as well as oxidative stress markers, namely, 3-nitrotyrosine (3-NT and 4-hydroxynonenal (4-HNE. Together, these results suggest that NAC exhibits significant protective effects against MA-induced dopaminergic cell death, presumably via modulation of the GSH level and autophagy. Collectively, our data provide mechanistic insights into the role of cellular GSH redox status in MA-induced autophagy and apoptotic cell death, and additional studies are needed to determine the therapeutic effectiveness of cellular redox modifiers in attenuating dopaminergic neurodegeneration in vivo.

  18. Mesenchymal stem cells promote cell invasion and migration and autophagy-induced epithelial-mesenchymal transition in A549 lung adenocarcinoma cells.

    Science.gov (United States)

    Luo, Dan; Hu, Shiyuan; Tang, Chunlan; Liu, Guoxiang

    2018-03-01

    Mesenchymal stem cells (MSCs) are recruited into the tumour microenvironment and promote tumour growth and metastasis. Tumour microenvironment-induced autophagy is considered to suppress primary tumour formation by impairing migration and invasion. Whether these recruited MSCs regulate tumour autophagy and whether autophagy affects tumour growth are controversial. Our data showed that MSCs promote autophagy activation, reactive oxygen species production, and epithelial-mesenchymal transition (EMT) as well as increased migration and invasion in A549 cells. Decreased expression of E-cadherin and increased expression of vimentin and Snail were observed in A549 cells cocultured with MSCs. Conversely, MSC coculture-mediated autophagy positively promoted tumour EMT. Autophagy inhibition suppressed MSC coculture-mediated EMT and reduced A549 cell migration and invasion slightly. Furthermore, the migratory and invasive abilities of A549 cells were additional increased when autophagy was further enhanced by rapamycin treatment. Taken together, this work suggests that microenvironments containing MSCs can promote autophagy activation for enhancing EMT; MSCs also increase the migratory and invasive abilities of A549 lung adenocarcinoma cells. Mesenchymal stem cell-containing microenvironments and MSC-induced autophagy signalling may be potential targets for blocking lung cancer cell migration and invasion. Copyright © 2018 John Wiley & Sons, Ltd.

  19. Deoxynivalenol exposure induces autophagy/apoptosis and epigenetic modification changes during porcine oocyte maturation

    International Nuclear Information System (INIS)

    Han, Jun; Wang, Qiao-Chu; Zhu, Cheng-Cheng; Liu, Jun; Zhang, Yu; Cui, Xiang-Shun; Kim, Nam-Hyung; Sun, Shao-Chen

    2016-01-01

    Deoxynivalenol (DON) is a widespread trichothecene mycotoxin which contaminates agricultural staples and elicits a complex spectrum of toxic effects on humans and animals. It has been shown that DON impairs oocyte maturation, reproductive function and causes abnormal fetal development in mammals; however, the mechanisms remain unclear. In the present study, we investigate the possible reasons of the toxic effects of DON on porcine oocytes. Our results showed that DON significantly inhibited porcine oocyte maturation and disrupted meiotic spindle by reducing p-MAPK protein level, which caused retardation of cell cycle progression. In addition, up-regulated LC3 protein expression and aberrant Lamp2, LC3 and mTOR mRNA levels were observed with DON exposure, together with Annexin V-FITC staining assay analysis, these results indicated that DON treatment induced autophagy/apoptosis in porcine oocytes. We also showed that DON exposure increased DNA methylation level in porcine oocytes through altering DNMT3A mRNA levels. Histone methylation levels were also changed showing with increased H3K27me3 and H3K4me2 protein levels, and mRNA levels of their relative methyltransferase genes, indicating that epigenetic modifications were affected. Taken together, our results suggested that DON exposure reduced porcine oocytes maturation capability through affecting cytoskeletal dynamics, cell cycle, autophagy/apoptosis and epigenetic modifications. - Highlights: • DON exposure disrupted meiotic spindle by reducing p-MAPK expression. • DON exposure caused retardation of cell cycle progression in porcine oocytes. • DON triggered autophagy and early-apoptosis in porcine oocytes. • DON exposure led to aberrant epigenetic modifications in porcine oocytes.

  20. Novel inducers of BECN1-independent autophagy: cis-unsaturated fatty acids.

    Science.gov (United States)

    Niso-Santano, Mireia; Bravo-San Pedro, José Manuel; Maiuri, Maria Chiara; Tavernarakis, Nektarios; Cecconi, Francesco; Madeo, Frank; Codogno, Patrice; Galluzzi, Lorenzo; Kroemer, Guido

    2015-01-01

    The induction of autophagy usually requires the activation of PIK3C3/VPS34 (phosphatidylinositol 3-kinase, catalytic subunit type 3) within a multiprotein complex that contains BECN1 (Beclin 1, autophagy related). PIK3C3 catalyzes the conversion of phosphatidylinositol into phosphatidylinositol 3-phosphate (PtdIns3P). PtdIns3P associates with growing phagophores, which recruit components of the autophagic machinery, including the lipidated form of MAP1LC3B/LC3 (microtubule-associated protein 1 light chain 3 β). Depletion of BECN1, PIK3C3 or some of their interactors suppresses the formation of MAP1LC3B(+) phagophores or autophagosomes elicited by most physiological stimuli, including saturated fatty acids. We observed that cis-unsaturated fatty acids stimulate the generation of cytosolic puncta containing lipidated MAP1LC3B as well as the autophagic turnover of long-lived proteins in the absence of PtdIns3P accumulation. In line with this notion, cis-unsaturated fatty acids require neither BECN1 nor PIK3C3 to stimulate the autophagic flux. Such a BECN1-independent autophagic response is phylogenetically conserved, manifesting in yeast, nematodes, mice and human cells. Importantly, MAP1LC3B(+) puncta elicited by cis-unsaturated fatty acids colocalize with Golgi apparatus markers. Moreover, the structural and functional collapse of the Golgi apparatus induced by brefeldin A inhibits cis-unsaturated fatty acid-triggered autophagy. It is tempting to speculate that the well-established health-promoting effects of cis-unsaturated fatty acids are linked to their unusual capacity to stimulate noncanonical, BECN1-independent autophagic responses.

  1. GMI, an Immunomodulatory Protein from Ganoderma microsporum, Potentiates Cisplatin-Induced Apoptosis via Autophagy in Lung Cancer Cells.

    Science.gov (United States)

    Hsin, I-Lun; Ou, Chu-Chyn; Wu, Ming-Fang; Jan, Ming-Shiou; Hsiao, Yi-Min; Lin, Ching-Hsiung; Ko, Jiunn-Liang

    2015-05-04

    Cisplatin-based therapy is common in the treatment of several types of cancers, including lung cancers. In our previous study, GMI, an immunomodulatory protein cloned from Ganoderma microsporum, induced a cytotoxic effect in lung cancer cells via autophagy. The aim of this study is to examine the role of GMI in enhancing cisplatin-mediated cell death. On the basis of MTT assay and Combination Index, GMI and cisplatin cotreatment induced a synergistic cytotoxic effect. GMI and cisplatin-induced apoptosis was determined by sub-G1, nuclear condensation, and annexin-V/propidium iodide analyses. On Western blot, expressions of γH2AX and cleaved forms of PARP, caspase-3, and caspase-7 were induced by combined treatment. Akt/mTOR pathway activity, LC3-II expression, and acidic vesicular organelle development demonstrated that cisplatin does not abolish GMI-mediated autophagy. Cyto-ID Green/hoechst 33342 double staining and time-dependent experiment indicated that GMI and cisplatin-treated A549 cells simultaneously express autophagosomes and apoptotic nuclei. To elucidate the role of autophagy in inducing apoptosis by GMI and cisplatin, chemical inhibitors and LC3 shRNA were used to inhibit autophagy. The results showed that 3-methyladenine decreases, while chloroquine increases GMI and cisplatin cotreatment-induced cleavage of caspase-7 and PARP. LC3 silencing abolished activation of apoptosis in A549 cells. Caspase inhibitors and caspase-7 silencing mitigated GMI and cisplatin-elicited cell viability inhibition and apoptosis. This is the first study to reveal the novel function of GMI in potentiating cisplatin-mediated apoptosis. GMI and cisplatin induce apoptosis via autophagy/caspase-7-dependent and survivin- and ERCC1-independent pathway. GMI may be a potential cisplatin adjuvant against lung cancer.

  2. Photodynamic N-TiO2 Nanoparticle Treatment Induces Controlled ROS-mediated Autophagy and Terminal Differentiation of Leukemia Cells

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    Moosavi, Mohammad Amin; Sharifi, Maryam; Ghafary, Soroush Moasses; Mohammadalipour, Zahra; Khataee, Alireza; Rahmati, Marveh; Hajjaran, Sadaf; ?os, Marek J.; Klonisch, Thomas; Ghavami, Saeid

    2016-01-01

    In this study, we used nitrogen-doped titanium dioxide (N-TiO2) NPs in conjugation with visible light, and show that both reactive oxygen species (ROS) and autophagy are induced by this novel NP-based photodynamic therapy (PDT) system. While well-dispersed N-TiO2 NPs (?100??g/ml) were inert, their photo-activation with visible light led to ROS-mediated autophagy in leukemia K562 cells and normal peripheral lymphocytes, and this increased in parallel with increasing NP concentrations and light...

  3. Autophagy regulation revealed by SapM-induced block of autophagosome-lysosome fusion via binding RAB7

    International Nuclear Information System (INIS)

    Hu, Dong; Wu, Jing; Wang, Wan; Mu, Min; Zhao, Runpeng; Xu, Xuewei; Chen, Zhaoquan; Xiao, Jian; Hu, Fengyu; Yang, Yabo; Zhang, Rongbo

    2015-01-01

    The mechanism underlying autophagy alteration by mycobacterium tuberculosis remains unclear. Our previous study shows LpqH, a lipoprotein of mycobacterium tuberculosis, can cause autophagosomes accumulation in murine macrophages. It is well known that SapM, another virulence factor, plays an important role in blocking phagosome-endosome fusion. However, the mechanism that SapM interferes with autophagy remains poorly defined. In this study, we report that SapM suppresses the autophagy flux by blocking autophagosome fusion with lysosome. Exposure to SapM results in accumulations of autophagosomes and decreased co-localization of autophagosome with lysosome. Molecularly, Rab7, a small GTPase, is blocked by SapM through its CT domain and is prevented from involvement of autophagosome-lysosome fusion. In conclusion, our study reveals that SapM takes Rab7 as a previously unknown target to govern a distinct molecular mechanism underlying autophagosome-lysosome fusion, which may bring light to a new thought about developing potential drugs or vaccines against tuberculosis. - Highlights: • A mechanism for disrupting autophagosome-lysosome fusion induced by SapM. • Rab7 is involved in SapM-inhibited autophagy. • SapM interacts with Rab7 by CT-domain. • CT-domain is indispensable to SapM-inhibited autophagy

  4. Autophagy regulation revealed by SapM-induced block of autophagosome-lysosome fusion via binding RAB7

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    Hu, Dong, E-mail: austhudong@126.com [Institute of Infection and Immunology, Department of Medical Immunology, Medical School, Anhui University of Science and Technology, Huainan (China); Wu, Jing, E-mail: wujing8008@126.com [Institute of Infection and Immunology, Department of Medical Immunology, Medical School, Anhui University of Science and Technology, Huainan (China); Wang, Wan; Mu, Min; Zhao, Runpeng; Xu, Xuewei; Chen, Zhaoquan [Institute of Infection and Immunology, Department of Medical Immunology, Medical School, Anhui University of Science and Technology, Huainan (China); Xiao, Jian [School of Pharmacy, Wenzhou Medical College, Wenzhou (China); Hu, Fengyu; Yang, Yabo [Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou (China); Zhang, Rongbo, E-mail: lory456@126.com [Institute of Infection and Immunology, Department of Medical Immunology, Medical School, Anhui University of Science and Technology, Huainan (China)

    2015-05-29

    The mechanism underlying autophagy alteration by mycobacterium tuberculosis remains unclear. Our previous study shows LpqH, a lipoprotein of mycobacterium tuberculosis, can cause autophagosomes accumulation in murine macrophages. It is well known that SapM, another virulence factor, plays an important role in blocking phagosome-endosome fusion. However, the mechanism that SapM interferes with autophagy remains poorly defined. In this study, we report that SapM suppresses the autophagy flux by blocking autophagosome fusion with lysosome. Exposure to SapM results in accumulations of autophagosomes and decreased co-localization of autophagosome with lysosome. Molecularly, Rab7, a small GTPase, is blocked by SapM through its CT domain and is prevented from involvement of autophagosome-lysosome fusion. In conclusion, our study reveals that SapM takes Rab7 as a previously unknown target to govern a distinct molecular mechanism underlying autophagosome-lysosome fusion, which may bring light to a new thought about developing potential drugs or vaccines against tuberculosis. - Highlights: • A mechanism for disrupting autophagosome-lysosome fusion induced by SapM. • Rab7 is involved in SapM-inhibited autophagy. • SapM interacts with Rab7 by CT-domain. • CT-domain is indispensable to SapM-inhibited autophagy.

  5. B-cell lymphoma 2 inhibitor ABT-737 induces Beclin1- and reactive oxygen species-dependent autophagy in Adriamycin-resistant human hepatocellular carcinoma cells.

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    Yao, Xiaoxiao; Li, Xiaoning; Zhang, Dan; Xie, Yingjun; Sun, Baozhen; Li, Hang; Sun, Liankun; Zhang, Xuewen

    2017-03-01

    ABT-737, a B-cell lymphoma 2 homology 3 mimetic, not only induces cell apoptosis by inhibiting the interaction of B-cell lymphoma 2 and Bax but also induces cell autophagy by interrupting the interaction of B-cell lymphoma 2 and Beclin1. Several recent studies have reported that ABT-737 has antitumor efficacy in diverse cancers. However, another study showed that hepatocellular carcinoma cells with high B-cell lymphoma 2 expression were resistant to ABT-737 compared to hepatocellular carcinoma cells with low B-cell lymphoma 2 expression. It was also found that ABT-737-induced autophagy is crucial for drug resistance. Here, we observed that of B-cell lymphoma 2 expression in Adriamycin-resistant human hepatocellular carcinoma HepG2/ADM cells is higher than that in human hepatocellular carcinoma HepG2 cells. Therefore, we further confirmed the mechanism and effect of autophagy induced by ABT-737 on apoptosis in HepG2/ADM cells with high B-cell lymphoma 2 expression. Our results showed that ABT-737 induced apoptosis and autophagy in time- and dose-dependent manner in HepG2/ADM cells, and this ABT-737-induced autophagy was Beclin1-dependent. In addition, we demonstrated that ABT-737 induced reactive oxygen species-mediated autophagy, and the reactive oxygen species-inhibitor N-acetyl-l-cysteine suppressed the reactive oxygen species-induced autophagy and ABT-737-induced increase in HepG2/ADM cell apoptosis. Furthermore, autophagy inhibitors increased HepG2/ADM cell apoptosis. In conclusion, our study further confirms that Beclin1- and reactive oxygen species-dependent autophagy induced by ABT-737 also plays a protective function in HepG2/ADM cells, which show B-cell lymphoma 2 expression higher than that in HepG2 cells.

  6. Cardiac-specific catalase overexpression rescues anthrax lethal toxin-induced cardiac contractile dysfunction: role of oxidative stress and autophagy.

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    Kandadi, Machender R; Yu, Xuejun; Frankel, Arthur E; Ren, Jun

    2012-11-07

    Lethal and edema toxins secreted by Bacillus anthracis during anthrax infection were found to incite serious cardiovascular complications. However, the underlying mechanisms in anthrax lethal toxin-induced cardiac anomalies remain unknown. This study was designed to evaluate the impact of antioxidant enzyme catalase in anthrax lethal toxin-induced cardiomyocyte contractile dysfunction. Wild type (WT) and cardiac-specific catalase overexpression mice were challenged with lethal toxin (2 μg/g, intraperotineally (i.p.)). Cardiomyocyte contractile and intracellular Ca(2+) properties were assessed 18 h later using an IonOptix edge-detection system. Proteasome function was assessed using chymotrypsin-like and caspase-like activities. GFP-LC3 puncta and Western blot analysis were used to evaluate autophagy and protein ubiquitination. Lethal toxin exposure suppressed cardiomyocyte contractile function (suppressed peak shortening, maximal velocity of shortening/re-lengthening, prolonged duration of shortening/re-lengthening, and impaired intracellular Ca(2+) handling), the effects of which were alleviated by catalase. In addition, lethal toxin triggered autophagy, mitochondrial and ubiquitin-proteasome defects, the effects of which were mitigated by catalase. Pretreatment of cardiomyocytes from catalase mice with the autophagy inducer rapamycin significantly attenuated or ablated catalase-offered protection against lethal toxin-induced cardiomyocyte dysfunction. On the other hand, the autophagy inhibitor 3-MA ablated or significantly attenuated lethal toxin-induced cardiomyocyte contractile anomalies. Our results suggest that catalase is protective against anthrax lethal toxin-induced cardiomyocyte contractile and intracellular Ca(2+) anomalies, possibly through regulation of autophagy and mitochondrial function.

  7. Cardiac-specific catalase overexpression rescues anthrax lethal toxin-induced cardiac contractile dysfunction: role of oxidative stress and autophagy

    Directory of Open Access Journals (Sweden)

    Kandadi Machender R

    2012-11-01

    Full Text Available Abstract Background Lethal and edema toxins secreted by Bacillus anthracis during anthrax infection were found to incite serious cardiovascular complications. However, the underlying mechanisms in anthrax lethal toxin-induced cardiac anomalies remain unknown. This study was designed to evaluate the impact of antioxidant enzyme catalase in anthrax lethal toxin-induced cardiomyocyte contractile dysfunction. Methods Wild type (WT and cardiac-specific catalase overexpression mice were challenged with lethal toxin (2 μg/g, intraperotineally (i.p.. Cardiomyocyte contractile and intracellular Ca2+ properties were assessed 18 h later using an IonOptix edge-detection system. Proteasome function was assessed using chymotrypsin-like and caspase-like activities. GFP-LC3 puncta and Western blot analysis were used to evaluate autophagy and protein ubiquitination. Results Lethal toxin exposure suppressed cardiomyocyte contractile function (suppressed peak shortening, maximal velocity of shortening/re-lengthening, prolonged duration of shortening/re-lengthening, and impaired intracellular Ca2+ handling, the effects of which were alleviated by catalase. In addition, lethal toxin triggered autophagy, mitochondrial and ubiquitin-proteasome defects, the effects of which were mitigated by catalase. Pretreatment of cardiomyocytes from catalase mice with the autophagy inducer rapamycin significantly attenuated or ablated catalase-offered protection against lethal toxin-induced cardiomyocyte dysfunction. On the other hand, the autophagy inhibitor 3-MA ablated or significantly attenuated lethal toxin-induced cardiomyocyte contractile anomalies. Conclusions Our results suggest that catalase is protective against anthrax lethal toxin-induced cardiomyocyte contractile and intracellular Ca2+ anomalies, possibly through regulation of autophagy and mitochondrial function.

  8. The Bcr-Abl kinase inhibitor INNO-406 induces autophagy and different modes of cell death execution in Bcr-Abl-positive leukemias.

    Science.gov (United States)

    Kamitsuji, Y; Kuroda, J; Kimura, S; Toyokuni, S; Watanabe, K; Ashihara, E; Tanaka, H; Yui, Y; Watanabe, M; Matsubara, H; Mizushima, Y; Hiraumi, Y; Kawata, E; Yoshikawa, T; Maekawa, T; Nakahata, T; Adachi, S

    2008-11-01

    Bcr-Abl tyrosine kinase (TK) inhibitors are promising therapeutic agents for Bcr-Abl-positive (Bcr-Abl(+)) leukemias. Although they are known to promote caspase-mediated apoptosis, it remains unclear whether caspase-independent cell death-inducing mechanisms are also triggered. Here we demonstrated that INNO-406, a second-generation Bcr-Abl TK inhibitor, induces programmed cell death (PCD) in chronic myelogenous leukemia (CML) cell lines through both caspase-mediated and caspase-independent pathways. The latter pathways include caspase-independent apoptosis (CIA) and necrosis-like cell death (CIND), and the cell lines varied regarding which mechanism was elicited upon INNO-406 treatment. We also observed that the propensity toward CIA or CIND in cells was strongly associated with cellular dependency on apoptosome-mediated caspase activity. Cells that undergo CIND have a high apoptosome activity potential whereas cells that undergo CIA tend to have a lower potential. Moreover, we found that INNO-406 promotes autophagy. When autophagy was inhibited with chloroquine or gene knockdown of beclin1 by shRNA, INNO-406-induced cell death was enhanced, which indicates that the autophagic response of the tumor cells is protective. These findings suggest new insights into the biology and therapy of Bcr-Abl(+) leukemias.

  9. Hexane fraction ofPluchea indicaroot extract inhibits proliferation and induces autophagy in human glioblastoma cells.

    Science.gov (United States)

    Cho, Chung-Lung; Lee, Ya-Zhe; Tseng, Chao-Neng; Cho, Joshua; Cheng, Yuan-Bin; Wang, Kuo-Wei; Chen, Han-Jung; Chiou, Shean-Jaw; Chou, Chia-Hua; Hong, Yi-Ren

    2017-11-01

    Pluchea indica (L.) Less. is a perennial plant known for its versatile uses in traditional medicine. Previous findings have shown that the extracts of Pluchea indica possess significant anti-inflammatory, anti-ulcer and anti-tuberculosis activity. The aim of this study was to demonstrate the anticancer activity of the hexane fraction of P. indica root extract (H-PIRE) in human glioblastoma cells using flow cytometric and western blot analysis. The results shoewd that, H-PIRE suppressed the growth of glioblastoma cells in a dose-dependent manner. H-PIRE treatment markedly decreased the population of cells in S and G2/M phases. The significant upregulation of acidic vesicular organelle (AVO) was detected during H-PIRE treatment. The expression levels of microtubule-associated light chain 3-II (LC3-II) protein, phosphorylated JNK and phosphorylated p38 were significantly increased, confirming the occurrence of autophagy during the process. Finally, the combination treatment of H-PIRE and LY294002, a pan PI3K inhibitor, further decreased cell viability, suggesting an additive anticancer effect. Taken together, our results suggest that H-PIRE suppresses the proliferation of glioblastoma cells by inducing cell cycle arrest and autophagy.

  10. Silica Nanoparticles Induce Oxidative Stress and Autophagy but Not Apoptosis in the MRC-5 Cell Line.

    Science.gov (United States)

    Petrache Voicu, Sorina Nicoleta; Dinu, Diana; Sima, Cornelia; Hermenean, Anca; Ardelean, Aurel; Codrici, Elena; Stan, Miruna Silvia; Zărnescu, Otilia; Dinischiotu, Anca

    2015-12-10

    This study evaluated the in vitro effects of 62.5 µg/mL silica nanoparticles (SiO NPs) on MRC-5 human lung fibroblast cells for 24, 48 and 72 h. The nanoparticles' morphology, composition, and structure were investigated using high resolution transmission electron microscopy, selected area electron diffraction and X-ray diffraction. Our study showed a decreased cell viability and the induction of cellular oxidative stress as evidenced by an increased level of reactive oxygen species (ROS), carbonyl groups, and advanced oxidation protein products after 24, 48, and 72 h, as well as a decreased concentration of glutathione (GSH) and protein sulfhydryl groups. The protein expression of Hsp27, Hsp60, and Hsp90 decreased at all time intervals, while the level of protein Hsp70 remained unchanged during the exposure. Similarly, the expression of p53, MDM2 and Bcl-2 was significantly decreased for all time intervals, while the expression of Bax, a marker for apoptosis, was insignificantly downregulated. These results correlated with the increase of pro-caspase 3 expression. The role of autophagy in cellular response to SiO₂NPs was demonstrated by a fluorescence-labeled method and by an increased level of LC3-II/LC3-I ratio. Taken together, our data suggested that SiO₂ NPs induced ROS-mediated autophagy in MRC-5 cells as a possible mechanism of cell survival.

  11. c-Ski inhibits autophagy of vascular smooth muscle cells induced by oxLDL and PDGF.

    Science.gov (United States)

    Li, Jun; Zhao, Li; Yang, Ting; Zeng, Yi-Jun; Yang, Kang

    2014-01-01

    Autophagy is increasingly being recognized as a critical determinant of vascular smooth muscle cell (VSMC) biology. Previously, we have demonstrated that c-Ski inhibits VSMC proliferation stimulated by transforming growth factor β (TGF-β), but it is not clear whether c-Ski has the similar protective role against other vascular injury factors and whether regulation of autophagy is involved in its protective effects on VSMC. Accordingly, in this study, rat aortic A10 VSMCs were treated with 40 µg/ml oxidized low-density lipoprotein (oxLDL) or 20 ng/ml platelet-derived growth factor (PDGF), both of which were autophagy inducers and closely related to the abnormal proliferation of VSMCs. Overexpression of c-Ski in A10 cells significantly suppressed the oxLDL- and PDGF- induced autophagy. This action of c-Ski resulted in inhibiting the cell proliferation, the decrease of contractile phenotype marker α-SMA expression while the increase of synthetic phenotype marker osteopontin expression stimulated by oxLDL or PDGF. Inversely, knockdown of c-Ski by RNAi enhanced the stimulatory effects of oxLDL or PDGF on A10 cell growth and phenotype transition. And further investigation found that inhibition of AKT phosphorylation to downregulate proliferating cell nuclear antigen (PCNA) expression, was involved in the regulation of autophagy and associated functions by c-Ski in the oxLDL- and PDGF-stimulated VSMCs. Collectively, c-Ski may play an important role in inhibiting autophagy to protect VSMCs against some harsh stress including oxLDL and PDGF.

  12. c-Ski inhibits autophagy of vascular smooth muscle cells induced by oxLDL and PDGF.

    Directory of Open Access Journals (Sweden)

    Jun Li

    Full Text Available Autophagy is increasingly being recognized as a critical determinant of vascular smooth muscle cell (VSMC biology. Previously, we have demonstrated that c-Ski inhibits VSMC proliferation stimulated by transforming growth factor β (TGF-β, but it is not clear whether c-Ski has the similar protective role against other vascular injury factors and whether regulation of autophagy is involved in its protective effects on VSMC. Accordingly, in this study, rat aortic A10 VSMCs were treated with 40 µg/ml oxidized low-density lipoprotein (oxLDL or 20 ng/ml platelet-derived growth factor (PDGF, both of which were autophagy inducers and closely related to the abnormal proliferation of VSMCs. Overexpression of c-Ski in A10 cells significantly suppressed the oxLDL- and PDGF- induced autophagy. This action of c-Ski resulted in inhibiting the cell proliferation, the decrease of contractile phenotype marker α-SMA expression while the increase of synthetic phenotype marker osteopontin expression stimulated by oxLDL or PDGF. Inversely, knockdown of c-Ski by RNAi enhanced the stimulatory effects of oxLDL or PDGF on A10 cell growth and phenotype transition. And further investigation found that inhibition of AKT phosphorylation to downregulate proliferating cell nuclear antigen (PCNA expression, was involved in the regulation of autophagy and associated functions by c-Ski in the oxLDL- and PDGF-stimulated VSMCs. Collectively, c-Ski may play an important role in inhibiting autophagy to protect VSMCs against some harsh stress including oxLDL and PDGF.

  13. ADIPOQ/adiponectin induces cytotoxic autophagy in breast cancer cells through STK11/LKB1-mediated activation of the AMPK-ULK1 axis.

    Science.gov (United States)

    Chung, Seung J; Nagaraju, Ganji Purnachandra; Nagalingam, Arumugam; Muniraj, Nethaji; Kuppusamy, Panjamurthy; Walker, Alyssa; Woo, Juhyung; Győrffy, Balázs; Gabrielson, Ed; Saxena, Neeraj K; Sharma, Dipali

    2017-08-03

    ADIPOQ/adiponectin, an adipocytokine secreted by adipocytes in the breast tumor microenvironment, negatively regulates cancer cell growth hence increased levels of ADIPOQ/adiponectin are associated with decreased breast cancer growth. However, its mechanisms of action remain largely elusive. We report that ADIPOQ/adiponectin induces a robust accumulation of autophagosomes, increases MAP1LC3B-II/LC3B-II and decreases SQSTM1/p62 in breast cancer cells. ADIPOQ/adiponectin-treated cells and xenografts exhibit increased expression of autophagy-related proteins. LysoTracker Red-staining and tandem-mCherry-GFP-LC3B assay show that fusion of autophagosomes and lysosomes is augmented upon ADIPOQ/adiponectin treatment. ADIPOQ/adiponectin significantly inhibits breast cancer growth and induces apoptosis both in vitro and in vivo, and these events are preceded by macroautophagy/autophagy, which is integral for ADIPOQ/adiponectin-mediated cell death. Accordingly, blunting autophagosome formation, blocking autophagosome-lysosome fusion or genetic-knockout of BECN1/Beclin1 and ATG7 effectively impedes ADIPOQ/adiponectin induced growth-inhibition and apoptosis-induction. Mechanistic studies show that ADIPOQ/adiponectin reduces intracellular ATP levels and increases PRKAA1 phosphorylation leading to ULK1 activation. AMPK-inhibition abrogates ADIPOQ/adiponectin-induced ULK1-activation, LC3B-turnover and SQSTM1/p62-degradation while AMPK-activation potentiates ADIPOQ/adiponectin's effects. Further, ADIPOQ/adiponectin-mediated AMPK-activation and autophagy-induction are regulated by upstream master-kinase STK11/LKB1, which is a key node in antitumor function of ADIPOQ/adiponectin as STK11/LKB1-knockout abrogates ADIPOQ/adiponectin-mediated inhibition of breast tumorigenesis and molecular analyses of tumors corroborate in vitro mechanistic findings. ADIPOQ/adiponectin increases the efficacy of chemotherapeutic agents. Notably, high expression of ADIPOQ receptor ADIPOR2, ADIPOQ

  14. Detrusor myocyte autophagy protects the bladder function via inhibiting the inflammation in cyclophosphamide-induced cystitis in rats.

    Directory of Open Access Journals (Sweden)

    Jiang Zhao

    Full Text Available Autophagy, a highly conserved homeostatic cellular process that removes and recycles damaged proteins and organelles in response to cellular stress, is believed to play a crucial role in the immune response and inflammation. The role of autophagy in bladder cystitis, however, has not well been clarified. Here we investigate the role of detrusor myocytes autophagy (DMA in cyclophosphamide-induced cystitis animal model. 164 female Sprague-Dawley rats were randomized into three experimental groups and compared to three control groups, respectively. The expressions of microtubule-associated protein 1 light chain 3 (LC3, p-p70s6k (the phosphorylated form of ribosomal protein S6, SOD2 (superoxide dismutase 2 in the bladder muscular layer were measured using western blot. The co-location of LC3, alpha-smooth muscle actin (α-SMA, and autophagic vacuoles were investigated with double-labeled immunofluorescence and transmission electron microscopy (TEM. The expression of lL-1β, IL-6, IL-8, malondialdehyde (MDA, and glutathione (GSH in the detrusor layer were analyzed using ELISA. The bladder inflammation and the number of mast cells in the muscular layer were analyzed by histology. The bladder function was evaluated using cystometry. In cyclophosphamide-induced cystitis, autophagy was detected in detrusor myocytes by increased LC3, p-p70s6k expression, and autophagosomes. However, the presence of enhanced inflammation and oxidative stress in the cyclophosphamide-treated group suggest autophagy of detrusor myocytes may not be sufficiently activated. Inflammation and oxidative stress were significantly decreased and the bladder histology and micturition function were significantly improved with rapamycin (RAPA, autophagy agonist pre-treatment. In contrast, inflammation and oxidative stress were dramatically increased and the bladder histology and function were negatively affected with chloroquine (CQ, autophagy blocker pre-treated. These findings

  15. Formation of a Snf1-Mec1-Atg1 Module on Mitochondria Governs Energy Deprivation-Induced Autophagy by Regulating Mitochondrial Respiration.

    Science.gov (United States)

    Yi, Cong; Tong, Jingjing; Lu, Puzhong; Wang, Yizheng; Zhang, Jinxie; Sun, Chen; Yuan, Kangning; Xue, Renyu; Zou, Bing; Li, Nianzhong; Xiao, Shuhua; Dai, Chong; Huang, Yuwei; Xu, Liling; Li, Lin; Chen, She; Miao, Di; Deng, Haiteng; Li, Hongliang; Yu, Li

    2017-04-10

    Autophagy is essential for maintaining glucose homeostasis, but the mechanism by which energy deprivation activates autophagy is not fully understood. We show that Mec1/ATR, a member of the DNA damage response pathway, is essential for glucose starvation-induced autophagy. Mec1, Atg13, Atg1, and the energy-sensing kinase Snf1 are recruited to mitochondria shortly after glucose starvation. Mec1 is recruited through the adaptor protein Ggc1. Snf1 phosphorylates Mec1 on the mitochondrial surface, leading to recruitment of Atg1 to mitochondria. Furthermore, the Snf1-mediated Mec1 phosphorylation and mitochondrial recruitment of Atg1 are essential for maintaining mitochondrial respiration during glucose starvation, and active mitochondrial respiration is required for energy deprivation-activated autophagy. Thus, formation of a Snf1-Mec1-Atg1 module on mitochondria governs energy deprivation-induced autophagy by regulating mitochondrial respiration. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Cannabinoid action induces autophagy-mediated cell death through stimulation of ER stress in human glioma cells.

    Science.gov (United States)

    Salazar, María; Carracedo, Arkaitz; Salanueva, Iñigo J; Hernández-Tiedra, Sonia; Lorente, Mar; Egia, Ainara; Vázquez, Patricia; Blázquez, Cristina; Torres, Sofía; García, Stephane; Nowak, Jonathan; Fimia, Gian María; Piacentini, Mauro; Cecconi, Francesco; Pandolfi, Pier Paolo; González-Feria, Luis; Iovanna, Juan L; Guzmán, Manuel; Boya, Patricia; Velasco, Guillermo

    2009-05-01

    Autophagy can promote cell survival or cell death, but the molecular basis underlying its dual role in cancer remains obscure. Here we demonstrate that delta(9)-tetrahydrocannabinol (THC), the main active component of marijuana, induces human glioma cell death through stimulation of autophagy. Our data indicate that THC induced ceramide accumulation and eukaryotic translation initiation factor 2alpha (eIF2alpha) phosphorylation and thereby activated an ER stress response that promoted autophagy via tribbles homolog 3-dependent (TRB3-dependent) inhibition of the Akt/mammalian target of rapamycin complex 1 (mTORC1) axis. We also showed that autophagy is upstream of apoptosis in cannabinoid-induced human and mouse cancer cell death and that activation of this pathway was necessary for the antitumor action of cannabinoids in vivo. These findings describe a mechanism by which THC can promote the autophagic death of human and mouse cancer cells and provide evidence that cannabinoid administration may be an effective therapeutic strategy for targeting human cancers.

  17. VMP1 related autophagy and apoptosis in colorectal cancer cells: VMP1 regulates cell death

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    Qian, Qinyi [Department of Ultrasonograph, Changshu No. 2 People’s Hospital, Changshu (China); Zhou, Hao; Chen, Yan [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Shen, Chenglong [Department of General Surgery, Changshu No. 2 People’s Hospital, Changshu (China); He, Songbing; Zhao, Hua; Wang, Liang [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Wan, Daiwei, E-mail: 372710369@qq.com [Department of Hepatobiliary Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou (China); Gu, Wen, E-mail: 505339704@qq.com [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China)

    2014-01-17

    Highlights: •This research confirmed VMP1 as a regulator of autophagy in colorectal cancer cell lines. •We proved the pro-survival role of VMP1-mediated autophagy in colorectal cancer cell lines. •We found the interaction between VMP1 and BECLIN1 also existing in colorectal cancer cell lines. -- Abstract: Vacuole membrane protein 1 (VMP1) is an autophagy-related protein and identified as a key regulator of autophagy in recent years. In pancreatic cell lines, VMP1-dependent autophagy has been linked to positive regulation of apoptosis. However, there are no published reports on the role of VMP1 in autophagy and apoptosis in colorectal cancers. Therefore, to address this gap of knowledge, we decided to interrogate regulation of autophagy and apoptosis by VMP1. We have studied the induction of autophagy by starvation and rapamycin treatment in colorectal cell lines using electron microscopy, immunofluorescence, and immunoblotting. We found that starvation-induced autophagy correlated with an increase in VMP1 expression, that VMP1 interacted with BECLIN1, and that siRNA mediated down-regulation of VMP1-reduced autophagy. Next, we examined the relationship between VMP1-dependent autophagy and apoptosis and found that VMP1 down-regulation sensitizes cells to apoptosis and that agents that induce apoptosis down-regulate VMP1. In conclusion, similar to its reported role in other cell types, VMP1 is an important regulator of autophagy in colorectal cell lines. However, in contrast to its role in pancreatic cell lines, in colorectal cancer cells, VMP1-dependent autophagy appears to be pro-survival rather than pro-cell death.

  18. Impacts of autophagy-inducing ingredient of areca nut on tumor cells.

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    Ching-Yu Yen

    Full Text Available Areca nut (AN is a popular carcinogen used by about 0.6-1.2 billion people worldwide. Although AN contains apoptosis-inducing ingredients, we previously demonstrated that both AN extract (ANE and its 30-100 kDa fraction (ANE 30-100K predominantly induce autophagic cell death in both normal and malignant cells. In this study, we further explored the action mechanism of ANE 30-100K-induced autophagy (AIA in Jurkat T lymphocytes and carcinoma cell lines including OECM-1 (mouth, CE81T/VGH (esophagus, SCC25 (tongue, and SCC-15 (tongue. The results showed that chemical- and small hairpin RNA (shRNA-mediated inhibition of AMP-activated protein kinase (AMPK resulted in the attenuation of AIA in Jurkat T but not in OECM-1 cells. Knockdown of Atg5 and Beclin 1 expressions ameliorated AIA in OECM-1/CE81T/VGH/Jurkat T and OECM-1/SCC25/SCC-15, respectively. Furthermore, ANE 30-100K could activate caspase-3 after inhibition of Beclin 1 expression in OECM-1/SCC25/SCC15 cells. Meanwhile, AMPK was demonstrated to be the upstream activator of the extracellular-regulated kinase (ERK in Jurkat T cells, and inhibition of MEK attenuated AIA in Jurkat T/OECM-1/CE81T/VGH cells. Finally, we also found that multiple myeloma RPMI8226, lymphoma U937, and SCC15 cells survived from long-term non-cytotoxic ANE 30-100K treatment exhibited stronger resistance against serum deprivation through upregulated autophagy. Collectively, our studies indicate that Beclin-1 and Atg5 but not AMPK are commonly required for AIA, and MEK/ERK pathway is involved in AIA. Meanwhile, it is also suggested that long-term AN usage might increase the resistance of survived tumor cells against serum-limited conditions.

  19. The nuclear receptor NR4A1 induces a form of cell death dependent on autophagy in mammalian cells.

    Directory of Open Access Journals (Sweden)

    Jimena Bouzas-Rodríguez

    Full Text Available The control of cell death is a biological process essential for proper development, and for preventing devastating pathologies like cancer and neurodegeneration. On the other hand, autophagy regulation is essential for protein and organelle degradation, and its dysfunction is associated with overlapping pathologies like cancer and neurodegeneration, but also for microbial infection and aging. In the present report we show that two evolutionarily unrelated receptors--Neurokinin 1 Receptor (NK(1R, a G-protein coupled receptor, and Insulin-like Growth Factor 1 Receptor (IGF1R, a tyrosine kinase receptor--both induce non-apoptotic cell death with autophagic features and requiring the activity of the autophagic core machinery proteins PI3K-III, Beclin-1 and Atg7. Remarkably, this form of cell death occurs in apoptosis-competent cells. The signal transduction pathways engaged by these receptors both converged on the activation of the nuclear receptor NR4A1, which has previously been shown to play a critical role in some paradigms of apoptosis and in NK(1R-induced cell death. The activity of NR4A1 was necessary for IGF1R-induced cell death, as well as for a canonical model of cell death by autophagy induced by the presence of a pan-caspase inhibitor, suggesting that NR4A1 is a general modulator of this kind of cell death. During cell death by autophagy, NR4A1 was transcriptionally competent, even though a fraction of it was present in the cytoplasm. Interestingly, NR4A1 interacts with the tumor suppressor p53 but not with Beclin-1 complex. Therefore the mechanism to promote cell death by autophagy might involve regulation of gene expression, as well as protein interactions. Understanding the molecular basis of autophagy and cell death mediation by NR4A1, should provide novel insights and targets for therapeutic intervention.

  20. Autophagy in the immune response to tuberculosis: clinical perspectives.

    LENUS (Irish Health Repository)

    Ní Cheallaigh, C

    2011-06-01

    A growing body of evidence points to autophagy as an essential component in the immune response to tuberculosis. Autophagy is a direct mechanism of killing intracellular Mycobacterium tuberculosis and also acts as a modulator of proinflammatory cytokine secretion. In addition, autophagy plays a key role in antigen processing and presentation. Autophagy is modulated by cytokines; it is stimulated by T helper type 1 (Th1) cytokines such as tumour necrosis factor (TNF)-α and interferon (IFN)-γ, and is inhibited by the Th2 cytokines interleukin (IL)-4 and IL-13 and the anti-inflammatory cytokine IL-10. Vitamin D, via cathelicidin, can also induce autophagy, as can Toll-like receptor (TLR)-mediated signals. Autophagy-promoting agents, administered either locally to the lungs or systemically, could have a clinical application as adjunctive treatment of drug-resistant and drug-sensitive tuberculosis. Moreover, vaccines which effectively induce autophagy could be more successful in preventing acquisition or reactivation of latent tuberculosis.

  1. Caspase-mediated cleavage of Beclin1 inhibits autophagy and promotes apoptosis induced by S1 in human ovarian cancer SKOV3 cells.

    Science.gov (United States)

    Li, Xiaoning; Su, Jing; Xia, Meihui; Li, Hongyan; Xu, Ye; Ma, Chunhui; Ma, Liwei; Kang, Jingsong; Yu, Huimei; Zhang, Zhichao; Sun, Liankun

    2016-02-01

    S1, a novel BH3 mimetic, can induce apoptosis dependent on Bax/Bak through inhibition of Bcl-2 in various tumors. S1 also induces autophagy through interrupting the interaction of Bcl-2 and Beclin1. Our results showed that S1 induces apoptosis in human ovarian cancer SKOV3 cells in a time- and dose-dependent manner. Autophagy precedes apoptosis, in SKOV3 cells treated with S1 (6 μmol/L), autophagy reached the maximum peak at 12 h after treatment and decreased to 24 h. In SKOV3 cells treated with different concentrations of S1 for 24 h, the highest level of autophagy was observed with 5 μmol/L and decreased to 10 μmol/L. Autophagy inhibitors 3-MA and CQ enhanced apoptosis induced by S1 in SKOV3 cells. However, overactivation of caspases in apoptosis induced by S1 may inhibit the autophagy-inducing function of Beclin1. Because the pan-caspase inhibitor Z-VAD recovered the autophagy-inducing function of Beclin1 through reduction of activated caspase-mediated cleavage of Beclin1. Furthermore, the Beclin1 cleavage products could further increase apoptosis induced by S1 in SKOV3 cells. This indicates that apoptosis induced by high doses and long exposure of S1 causes the overactivation of caspases and subsequent cleavage of Beclin1, and inhibits the protection of autophagy. Moreover, the cleaved product of Beclin1 further promotes apoptosis induced by S1 in SKOV3 cells. Our results suggest this may be a molecular mechanism for enhancing the sensitivity of cancer cells to apoptosis induced by small molecular compound targeting Bcl-2.

  2. Rcan1-1L overexpression induces mitochondrial autophagy and improves cell survival in angiotensin II-exposed cardiomyocytes

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    Duan, Hongyan; Li, Yongqiang; Yan, Lijie; Yang, Haitao; Wu, Jintao; Qian, Peng; Li, Bing; Wang, Shanling, E-mail: shanglingwang@126.com

    2015-07-01

    Mitochondrial autophagy is an important adaptive stress response and can be modulated by various key molecules. A previous study found that the regulator of calcineurin 1-1L (Rcan1-1L) may regulate mitochondrial autophagy and cause mitochondria degradation in neurocytes. However, the effect of Rcan1-1L on cardiomyocytes has not been determined. In the present study, we aimed to investigate the role of Rcan1-1L in angiotensin II (Ang II)-exposed human cardiomyocytes. Above all, Human adult cardiac myocytes (HACMs) were exposed to 200 nmol/L Ang II for 4 days. Enhanced H{sub 2}O{sub 2} production, cytochrome C release and mitochondrial permeability were observed in these cells, which were blocked by valsartan. Consistently, Ang II exposure significantly reduced cardiomyocyte viability. However, transfection of Rcan1-1L vector promoted cell viability and ameliorated the apoptosis caused by Ang II. Rcan1-1L clearly promoted mitochondrial autophagy in HACMs, with elevated autophagy protein (ATG) 5 and light chain 3 (LC3) expression. Transient mitochondrial biogenesis and reduced cytochrome C release was also induced by Rcan1-1L. Additionally, Rcan1-1L significantly inhibited calcineurin/nuclear factor of activated T cells (NFAT) signaling. We thus conclude that Rcan1-1L may play a protective role in Ang II-treated cardiomyocytes through the induction of mitochondrial autophagy, and may be an alternative method of cardiac protection. - Highlights: • Transfection of Rcan1-1L into HACMs promoted cell viability and reduced apoptosis. • Transfection of Rcan1-1L promoted mitochondrial autophagy in HACMs. • Rcan1-1L inhibited the calcineurin/nuclear factor of activated T cells signaling.

  3. Induction of Plac8 promotes pro-survival function of autophagy in cadmium-induced prostate carcinogenesis.

    Science.gov (United States)

    Kolluru, Venkatesh; Pal, Deeksha; Papu John, A M Sashi; Ankem, Murali K; Freedman, Jonathan H; Damodaran, Chendil

    2017-11-01

    Chronic exposure to cadmium is known to be a risk factor for human prostate cancer. Despite over-whelming evidence of cadmium causing carcinogenicity in humans, the specific underlying molecular mechanisms that govern metal-induced cellular transformation remain unclear. Acute exposure (up to 72 h) to cadmium induces apoptosis in normal prostate epithelial cells (RWPE-1), while chronic exposure (>1 year) transforms these cells to a malignant phenotype (cadmium-transformed prostate epithelial cells; CTPE). Increased expression of autophagy-regulated genes; Plac8, LC3B and Lamp-1; in CTPE cells was associated with cadmium-induced transformation. Increased expression of Plac8, a regulator of autophagosome/autolysosome fusion, facilitates the pro-survival function of autophagy and upregulation of pAKT (ser473) and NF-κβ, to allow CTPE to proliferate. Likewise, inhibition of Plac8 suppresses CTPE cell growth. Additionally, overexpression of Plac8 in RWPE-1 cells induces resistance to cadmium toxicity. Pharmacological inhibitors and an inducer of autophagy failed to affect Plac8 expression and CTPE cell viability, suggesting a unique role for Plac8 in cadmium-induced prostate epithelial cell transformation. These results support a role for Plac8 as an essential component in the cadmium-induced transformation of normal prostate epithelial cells to a cancerous state. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Autophagy induced by silica nanoparticles protects RAW264.7 macrophages from cell death.

    Science.gov (United States)

    Marquardt, Clarissa; Fritsch-Decker, Susanne; Al-Rawi, Marco; Diabaté, Silvia; Weiss, Carsten

    2017-03-15

    Although the technological and economic benefits of engineered nanomaterials are obvious, concerns have been raised about adverse effects if such material is inhaled, ingested, applied to the skin or even released into the environment. Here we studied the cytotoxic effects of the most abundant nanomaterial, silica nanoparticles (SiO 2 -NPs), in murine RAW264.7 macrophages. SiO 2 -NPs dose-dependently induce membrane leakage and cell death without obvious involvement of reactive oxygen species. Interestingly, at low concentrations SiO 2 -NPs trigger autophagy, evidenced by morphological and biochemical hallmarks such as autophagolysosomes or increased levels of LC3-II, which serves to protect cells from cytotoxicity. Hence SiO 2 -NPs initiate an adaptive stress response which dependent on dose serve to balance survival and death and ultimately dictates the cellular fate. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Triptolide Inhibited Cytotoxicity of Differentiated PC12 Cells Induced by Amyloid-Beta25–35 via the Autophagy Pathway

    Science.gov (United States)

    Xu, Pengjuan; Li, Zhigui; Wang, Hui; Zhang, Xiaochen; Yang, Zhuo

    2015-01-01

    Evidence shows that an abnormal deposition of amyloid beta-peptide25–35 (Aβ25–35) was the primary cause of the pathogenesis of Alzheimer’s disease (AD). And the elimination of Aβ25–35 is considered an important target for the treatment of AD. Triptolide (TP), isolated from Tripterygium wilfordii Hook.f. (TWHF), has been shown to possess a broad spectrum of biological profiles, including neurotrophic and neuroprotective effects. In our study investigating the effect and potential mechanism of triptolide on cytotoxicity of differentiated rat pheochromocytoma cell line (the PC12 cell line is often used as a neuronal developmental model) induced by Amyloid-Beta25–35 (Aβ25–35), we used 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) assay, flow cytometry, Western blot, and acridine orange staining to detect whether triptolide could inhibit Aβ25–35–induced cell apoptosis. We focused on the potential role of the autophagy pathway in Aβ25–35-treated differentiated PC12 cells. Our experiments show that cell viability is significantly decreased, and the apoptosis increased in Aβ25–35-treated differentiated PC12 cells. Meanwhile, Aβ25–35 treatment increased the expression of microtubule-associated protein light chain 3 II (LC3 II), which indicates an activation of autophagy. However, triptolide could protect differentiated PC12 cells against Aβ25–35-induced cytotoxicity and attenuate Aβ25–35-induced differentiated PC12 cell apoptosis. Triptolide could also suppress the level of autophagy. In order to assess the effect of autophagy on the protective effects of triptolide in differentiated PC12 cells treated with Aβ25–35, we used 3-Methyladenine (3-MA, an autophagy inhibitor) and rapamycin (an autophagy activator). MTT assay showed that 3-MA elevated cell viability compared with the Aβ25–35-treated group and rapamycin inhibits the protection of triptolide. These results suggest that triptolide will repair the

  6. Sirt3-Mediated Autophagy Contributes to Resveratrol-Induced Protection against ER Stress in HT22 Cells

    Directory of Open Access Journals (Sweden)

    Wen-Jun Yan

    2018-02-01

    Full Text Available Endoplasmic reticulum (ER stress occurring in stringent conditions is critically involved in neuronal survival and death. Resveratrol is a non-flavonoid polyphenol that has neuroprotective effects against many neurological disorders. Here, we investigated the potential protective effects of resveratrol in an in vitro ER stress model mimicked by tunicamycin (TM treatment in neuronal HT22 cells. We found that TM dose-dependently decreased cell viability and increased apoptosis, which were both significantly attenuated by resveratrol treatment. Resveratrol markedly reduced the expression or activation of ER stress-associated factors, including GRP78, CHOP, and caspase-12. The results of immunocytochemistry and western blot showed that resveratrol promoted autophagy in TM-treated cells, as evidenced by increased LC3II puncta number, bcelin1 expression and LC3II/LC3I ratio. Pretreatment with the autophagy inhibitor chloroquine could reduce the protective effects of resveratrol. In addition, the expression of Sirt3 protein and its downstream enzyme activities were significantly increased in resveratrol-treated HT22 cells. To confirm the involvement of Sirt3-mediated mechanisms, siRNA transfection was used to knockdown Sirt3 expression in vitro. The results showed that downregulation of Sirt3 could partially prevented the autophagy and protection induced by resveratrol after TM treatment. Our study demonstrates a pivotal role of Sirt3-mediated autophagy in mediating resveratrol-induced protection against ER stress in vitro, and suggests the therapeutic values of resveratrol in ER stress-associated neuronal injury conditions.

  7. Curcumin protects neuronal cells against status-epilepticus-induced hippocampal damage through induction of autophagy and inhibition of necroptosis.

    Science.gov (United States)

    Wang, Jin; Liu, Yuan; Li, Xiao-Hui; Zeng, Xiang-Chang; Li, Jian; Zhou, Jun; Xiao, Bo; Hu, Kai

    2017-05-01

    Status epilepticus, the most severe form of epilepsy, is characterized by progressive functional and structural damage in the hippocampus, ultimately leading to the development and clinical appearance of spontaneous, recurrent seizures. Although the pathogenesis underlying epileptogenesis processes remains unclear, a substantial body of evidence has shown that status epilepticus acts as an important initial factor in triggering epileptogenesis. Notably, besides classical cell death mechanisms such as apoptosis and necrosis, 2 novel regulators of cell fate known as necroptosis and autophagy, are demonstrated to be involved in neuronal damage in various neurodegenerative and neuropsychiatric disorders. However, whether necroptosis and autophagy play a role in post-status-epilepticus rat hippocampus and other epilepsy mechanisms deserves further research effort. In addition, research is needed to determine whether compounds from traditional Chinese herbs possess antiepileptic effects through the modulation of necroptosis and autophagy. In this study, we found that curcumin, a polyphenolic phytochemical extracted from the Curcuma longa plant, protects neuronal cells against status-epilepticus-induced hippocampal neuronal damage in the lithium-pilocarpine-induced status epilepticus rat model through induction of autophagy and inhibition of necroptosis.

  8. Regulation of autophagy via PERK-eIF2α effectively relieve the radiation myelitis induced by iodine-125.

    Directory of Open Access Journals (Sweden)

    Zuozhang Yang

    Full Text Available Radiation myelitis is the most serious complication in clinical radiotherapy for spinal metastases. We previously showed that (125I brachytherapy induced apoptosis of spinal cord neurons accompanied by autophagy. In this study, we further investigated the mechanism by which (125I radiation triggered autophagy in neural cells. We found that autophagy induced by (125I radiation was involved in endoplasmic reticulum (ER stress and mainly dependent on PERK-eIF2α pathway. The expressions of LC3II, ATG12 and PI3K were significantly suppressed in PERK knockout neural cells. Meanwhile, the expressions of phosphorylated-Akt s473 and caspase3/8 all significantly increased in neural cells transfected with a PERK siRNA and which enhanced apoptosis of neurons after (125I radiation. The results were consistent with that by MTT and Annexin-FITC/PT staining. In animal model of banna pigs with radiation myelitis caused by (125I brachytherapy, we have successfully decreased PERK expression by intrathecal administration of the lentivirus vector. The apoptosis rate was significantly higher than that in control group and which deteriorated radiation myelitis of banna pigs. Thus, autophagy caused by (125I radiation was mainly as an attempt of cell survival at an early stage, but it would be a self-destructive process and promoted the process of apoptosis and necrosis radiated by (125I for more than 72 hours. The study would be useful and helpful to maximize efficiency of radiation therapy in clinical therapy.

  9. Downregulation of B-cell lymphoma/leukemia-2 by overexpressed microRNA 34a enhanced titanium dioxide nanoparticle-induced autophagy in BEAS-2B cells

    Science.gov (United States)

    Bai, Wenlin; Chen, Yujiao; Sun, Pengling; Gao, Ai

    2016-01-01

    Titanium dioxide (TiO2) nanoparticles (TNPs) are manufactured worldwide for a wide range of applications and the toxic effect of TNPs on biological systems is gaining attention. Autophagy is recognized as an emerging toxicity mechanism triggered by nanomaterials. MicroRNA 34a (miR34a) acts as a tumor suppressor gene by targeting many oncogenes, but how it affects autophagy induced by TNPs is not completely understood. Here, we observed the activation of TNP-induced autophagy through monodansylcadaverine staining and LC3-I/LC3-II conversion. Meanwhile, the transmission electron microscope ultrastructural analysis showed typical morphological characteristics in autophagy process. We detected the expression of miR34a and B-cell lymphoma/leukemia-2 (Bcl-2). In addition, the underlying mechanism of TNP-induced autophagy was performed using overexpression of miR34a by lentivirus vector transfection. Results showed that TNPs induced autophagy generation evidently. Typical morphological changes in the process of autophagy were observed by the transmission electron microscope ultrastructural analysis and LC3-I/LC3-II conversion increased significantly in TNP-treated cells. Meanwhile, TNPs induced the downregulation of miR34a and increased the expression of Bcl-2. Furthermore, overexpressed miR34a decreased the expression of Bcl-2 both in messenger RNA and protein level, following which the level of autophagy and cell death rate increased after the transfected cells were incubated with TNPs for 24 hours. These findings provide the first evidence that overexpressed miR34a enhanced TNP-induced autophagy and cell death through targeted downregulation of Bcl-2 in BEAS-2B cells. PMID:27226226

  10. Thrombopoietin protects H9C2 cells from excessive autophagy and apoptosis in doxorubicin-induced cardiotoxicity

    Science.gov (United States)

    Wang, Han; Wang, Hua; Liang, En-Yu; Zhou, Li-Xia; Dong, Zhan-Ling; Liang, Ping; Weng, Qi-Fang; Yang, Mo

    2018-01-01

    Cardiac toxicity has been the major concern when using doxorubicin (DOX) in cancer therapy. Thrombopoietin (TPO) protects cardiac cells from DOX-induced cell damage; however, its molecular mechanism remains exclusive. The anti-autophagic and anti-apoptotic effects of TPO upon DOX treatment were studied in the cardiac H9C2 cell line, with bafilomycin A1 treatment as a positive control for autophagy inhibition. Cell viability was measured by Cell Counting Kit-8 assay in different treatment groups. The mRNA and/or protein levels of apoptotic markers and autophagy-associated factors were detected. The mean number of microtubule-associated protein 1A/1B-light chain 3 (LC3) puncta per cell was quantified to indicate autophagosomes and autolysosomes, of which the ones co-stained with lysosomal-associated membrane protein 1 were considered as autolysosomes. DOX treatment (5 µg/ml, 24 h) significantly impaired H9C2 cell viability compared with the control, while TPO pretreatment (10 ng/ml, 36 h) improved cell viability upon DOX treatment. DOX exposure markedly increased LC3 puncta in H9C2 cells, and TPO pretreatment reduced the number of autophagosomes, but showed no significant inhibitory effect on autolysosome formation. The autophagy inhibition by TPO upon DOX treatment was confirmed according to protein quantification of LC3-II and nucleoporin 62. TPO also suppressed autophagy-promoting protein Beclin-1, and elevated the anti-autophagic factors GATA-binding protein-4 and B cell lymphoma-2. Furthermore, TPO reduced DOX-induced apoptosis in H9C2 cells, as reflected by the amount changes of caspase-3. Taken together, these results revealed that TPO has a protective role in H9C2 cells from DOX-induced autophagy as well as apoptosis, and indicated that TPO may act as a cardioprotective drug in DOX-treated patients. PMID:29403560

  11. Inhibition of autophagy by chloroquine induces apoptosis in primary effusion lymphoma in vitro and in vivo through induction of endoplasmic reticulum stress.

    Science.gov (United States)

    Masud Alam, Md; Kariya, Ryusho; Kawaguchi, Azusa; Matsuda, Kouki; Kudo, Eriko; Okada, Seiji

    2016-10-01

    Autophagy plays a crucial role in cancer cell survival and the inhibition of autophagy is attracting attention as an emerging strategy for the treatment of cancer. Chloroquine (CQ) is an anti-malarial drug, and is also known as an inhibitor of autophagy. Recently, it has been found that CQ induces cancer cell death through the inhibition of autophagy; however, the underlying mechanism is not entirely understood. In this study, we identified the role of CQ-induced cancer cell death using Primary Effusion Lymphoma (PEL) cells. We found that a CQ treatment induced caspase-dependent apoptosis in vitro. CQ also suppressed PEL cell growth in a PEL xenograft mouse model. We showed that CQ activated endoplasmic reticulum (ER) stress signal pathways and induced CHOP, which is an inducer of apoptosis. CQ-induced cell death was significantly decreased by salbrinal, an ER stress inhibitor, indicating that CQ-induced apoptosis in PEL cells depended on ER stress. We show here for the first time that the inhibition of autophagy induces ER stress-mediated apoptosis in PEL cells. Thus, the inhibition of autophagy is a novel strategy for cancer chemotherapy.

  12. Diet-induced obesity impairs endometrial stromal cell decidualization: a potential role for impaired autophagy.

    Science.gov (United States)

    Rhee, Julie S; Saben, Jessica L; Mayer, Allyson L; Schulte, Maureen B; Asghar, Zeenat; Stephens, Claire; Chi, Maggie M-Y; Moley, Kelle H

    2016-06-01

    What effect does diet-induced obesity have on endometrial stromal cell (ESC) decidualization? Diet-induced obesity impairs ESC decidualization. Decidualization is important for successful implantation and subsequent health of the pregnancy. Compared with normal-weight women, obese women have lower pregnancy rates (both spontaneous and by assisted reproductive technology), higher rates of early pregnancy loss and poorer oocyte quality. Beginning at 6 weeks of age, female C57Bl/6J mice were fed either a high-fat/high-sugar diet (HF/HS; 58% Fat Energy/Sucrose) or a diet of standard mouse chow (CON; 13% Fat) for 12 weeks. At this point, metabolic parameters were measured. Some of the mice (n = 9 HF/HS and 9 CON) were mated with reproductively competent males, and implantation sites were assessed. Other mice (n = 11 HF/HS and 10 CON) were mated with vasectomized males, and artificial decidualization was induced. For in vitro human studies of primary ESCs, endometrial tissue was obtained via biopsy from normo-ovulatory patients without history of infertility (obese = BMI > 30 kg/m(2), n = 11 and lean = BMI treatment with cAMP and medroxyprogesterone. The level of expression of decidualization markers was assessed by RT-qPCR (mRNA) and western blotting (protein). ATP content of ESCs was measured, and levels of autophagy were assessed by western blotting of the autophagy regulators acetyl coa carboxylase (ACC) and ULK1 (Ser 317). Autophagic flux was measured by western blot of the marker LC3b-II. Mice exposed to an HF/HS diet became obese and metabolically impaired. HF/HS-exposed mice mated to reproductively competent males had smaller implantation sites in early pregnancy (P obese women than in those of normal-weight women (Ptreatment abrogated this increase. Many aspects of obesity and metabolic impairment could contribute to the decidualization defects observed in the HF/HS-exposed mice. Although our findings suggest that both autophagy and decidualization are impaired

  13. Andrographolide sodium bisulfate-induced apoptosis and autophagy in human proximal tubular endothelial cells is a ROS-mediated pathway.

    Science.gov (United States)

    Lu, Hong; Zhang, Xin-Yue; Wang, Yi-Qi; Zheng, Xiao-Liang; Yin-Zhao; Xing, Wen-Min; Zhang, Qin

    2014-03-01

    The nephrotoxic mechanisms of andrographolide sodium bisulfate (ASB) remain largely unknown. This study attempted to explore the mechanism of ASB-induced nephrotoxicity using human proximal tubular endothelial cells (HK-2). For this study HK-2 cells were treated with rising concentrations of ASB. Their survival rate was detected using MTT assay and ultrastructure was observed with electron microscopy. L-Lactate dehydrogenase (LDH) assay was followed by examination of mitochondrial membrane potential (MMP). Reactive oxygen species (ROS) was detected using different methods and apoptosis/autophage related proteins were detected using immunoblotting. We found that ASB inhibited HK-2 cell proliferation and decreased cell survival rate in a time and dose-dependent manner (Papoptosis and autophagy were observed. MMP gradually decreased and ROS was induced. The expression of JNK and Beclin-1 increased and activation of the JNK signaling pathway were seen. Apoptosis was induced via the mitochondrial-dependent caspase-3 and caspase-9 pathway, and autophagy related protein Beclin-1 was enhanced by ASB. The data show that ASB induces high levels of ROS generation in HK-2 cells and activates JNK signaling. Furthermore, ASB induces cell apoptosis via the caspase-dependent mitochondrial pathway, and induces cellular autophagy, in part by enhancing Beclin-1 protein expression. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Crosstalk between 6-OHDA-induced autophagy and apoptosis in PC12 cells is mediated by phosphorylation of Raf-1/ERK1/2.

    Science.gov (United States)

    Li, Jing; Ma, Lan; Fan, Ying; Zhang, Yina; Sun, Dianjun; Wu, Bo

    2016-08-01

    Parkinson's disease (PD) is a degenerative brain disorder characterized by motor symptoms and loss of dopaminergic (DA) neurons in the substantia nigra. The mechanisms for DA cell death in PD have been extensively investigated using PC12 cells treated with a dopamine neurotoxin 6-hydroxydopamine (6-OHDA). 6-OHDA may induce both autophagy and apoptosis in PC12 cells. However, it remains unclear whether crosstalk occurs between autophagy and apoptosis in PC12 cells treated with 6-OHDA and whether Raf-1/ERK1/2 and their phosphorylation status play a role in autophagy. In this study, we used MDC staining assay and flow cytometry and found that 6-OHDA induced autophagy in PC12 cells. This induction was inhibited by the autophagy inhibitor 3-MA. Our electron microscopy observations also supported 6-OHDA induced autophagy in PC12 cells. Apoptosis of PC12 cells was increased with inhibition of autophagy by 3-MA. In addition, Inhibition of Raf-1 resulted in a decreased 6-OHDA-induced autophagy rate among PC12 cells. Phosphorylation levels of Raf-1 and ERK1/2 were increased in PC12 cells treated with 6-OHDA and inhibited by co-treatment with 6-OHDA and 3-MA. These data suggest that crosstalk between 6-OHDA-induced apoptosis and autophagy in PC12 cells may be regulated via the Raf-1/ERK1/2 signaling pathway. Our data suggest a mechanism for 6-OHDA toxicity in PC12 cells, contributing to our understanding of the pathogenesis of PD.

  15. Verapamil stereoisomers induce antiproliferative effects in vascular smooth muscle cells via autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Salabei, Joshua K. [Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202 (United States); Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, KY 40202 (United States); Balakumaran, Arun [Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States); Frey, Justin C. [Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI 54702 (United States); Boor, Paul J. [Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States); Treinen-Moslen, Mary [Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555‐0609 (United States); Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States); Conklin, Daniel J., E-mail: dj.conklin@louisville.edu [Diabetes and Obesity Center, University of Louisville, Louisville, KY 40202 (United States); Division of Cardiovascular Medicine, University of Louisville, Louisville, KY 40202 (United States); Department of Biology, University of Wisconsin-Eau Claire, Eau Claire, WI 54702 (United States); Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555‐0438 (United States)

    2012-08-01

    Calcium channel blockers (CCBs) are important in the management of hypertension and limit restenosis. Although CCB efficacy could derive from decreased blood pressure, other mechanisms independent of CCB activity also can contribute to antiproliferative action. To understand mechanisms of CCB-mediated antiproliferation, we studied two structurally dissimilar CCBs, diltiazem and verapamil, in cultured rat vascular smooth muscle cells (VSMC). To elucidate CCB-independent effects, pure stereoisomers of verapamil (R-verapamil, inactive VR; S-verapamil, active, VS) were used. The effects of CCB exposure on cell viability (MTT reduction), cell proliferation ({sup 3}H-thymidine incorporation), VSMC morphology by light and transmission electron microscopy (TEM) and autophagy (LC3I/II, ATG5) were measured. In general, verapamil, VR or VS treatment alone (80 μM) appreciably enhanced MTT absorbance although higher concentrations (VR or VS) slightly decreased MTT absorbance. Diltiazem (140 μM) markedly decreased MTT absorbance (40%) at 120 h. VR or VS treatment inhibited {sup 3}H-thymidine incorporation (24 h) and induced cytological alterations (i.e., karyokinesis, enhanced perinuclear MTT deposition, accumulated perinuclear “vacuoles”). TEM revealed perinuclear “vacuoles” to be aggregates of highly laminated and electron-dense vesicles resembling autophagosomes and lysosomes, respectively. Increased autophagosome activity was confirmed by a concentration-dependent increase in LC3-II formation by Western blotting and by increased perinuclear LC3-GFP{sup +} puncta in verapamil-treated VSMC. Verapamil stereoisomers appeared to decrease perinuclear mitochondrial density. These observations indicate that antiproliferative effects of verapamil stereoisomers are produced by enhanced mitochondrial damage and upregulated autophagy in VSMC. These effects are independent of CCB activity indicating a distinct mechanism of action that could be targeted for more efficacious anti

  16. High intensity aerobic exercise training improves chronic intermittent hypoxia-induced insulin resistance without basal autophagy modulation.

    Science.gov (United States)

    Pauly, Marion; Assense, Allan; Rondon, Aurélie; Thomas, Amandine; Dubouchaud, Hervé; Freyssenet, Damien; Benoit, Henri; Castells, Josiane; Flore, Patrice

    2017-03-03

    Chronic intermittent hypoxia (IH) associated with obstructive sleep apnea (OSA) is a major risk factor for cardiovascular and metabolic diseases (insulin resistance: IR). Autophagy is involved in the pathophysiology of IR and high intensity training (HIT) has recently emerged as a potential therapy. We aimed to confirm IH-induced IR in a tissue-dependent way and to explore the preventive effect of HIT on IR-induced by IH. Thirty Swiss 129 male mice were randomly assigned to Normoxia (N), Intermittent Hypoxia (IH: 21-5% FiO 2 , 30 s cycle, 8 h/day) or IH associated with high intensity training (IH HIT). After 8 days of HIT (2*24 min, 50 to 90% of Maximal Aerobic Speed or MAS on a treadmill) mice underwent 14 days IH or N. We found that IH induced IR, characterized by a greater glycemia, an impaired insulin sensitivity and lower AKT phosphorylation in adipose tissue and liver. Nevertheless, MAS and AKT phosphorylation were greater in muscle after IH. IH associated with HIT induced better systemic insulin sensitivity and AKT phosphorylation in liver. Autophagy markers were not altered in both conditions. These findings suggest that HIT could represent a preventive strategy to limit IH-induced IR without change of basal autophagy.

  17. SIRT1 protects cardiac cells against apoptosis induced by zearalenone or its metabolites α- and β-zearalenol through an autophagy-dependent pathway

    International Nuclear Information System (INIS)

    Ben Salem, Intidhar; Boussabbeh, Manel; Da Silva, Julie Pires; Guilbert, Arnaud; Bacha, Hassen; Abid-Essefi, Salwa; Lemaire, Christophe

    2017-01-01

    Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium in cereals and agricultural products. The major ZEN metabolites are α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL). In the present study, we investigated the underlying mechanism of the toxicity induced by ZEN, α-ZOL and β-ZOL in cardiac cells (H9c2). We show that treatment with ZEN or its metabolites induces the activation of the mitochondrial pathway of apoptosis as characterized by an increase in ROS generation, a loss of mitochondrial transmembrane potential (ΔΨm) and an activation of caspases. Besides, we demonstrate that these mycotoxins promote the activation of autophagy before the onset of apoptosis. Indeed, we observed that a short-time (6 h) treatment with ZEN, α-ZOL or β-ZOL, increased the level of Beclin-1 and LC3-II and induced the accumulation of the CytoID® autophagy detection probe. Moreover, the inhibition of autophagy by Chloroquine significantly increased cell death induced by ZEN, α-ZOL or β-ZOL, suggesting that the activation of autophagy serves as a cardioprotective mechanism against these mycotoxins. In addition, we found that the inhibition (EX527) or the knockdown of SIRT1 (siRNA) significantly increased apoptosis induced by ZEN or its derivatives, whereas SIRT1 activation with RSV greatly prevents the cytotoxic effects of these mycotoxins. By contrast, when autophagy was inhibited by CQ, the activation of SIRT1 by RSV had no protection against the cardiotoxicity of ZEN or its metabolites, suggesting that SIRT1 protects cardiac cells by an autophagy-dependent pathway. - Highlights: • ZEN, α- and β-ZOL induce the mitochondrial pathway of apoptosis in cardiac cells. • Inhibition of autophagy enhanced ZEN-, α-ZOL- and β-ZOL-induced apoptosis. • SIRT1 activates autophagy to protect cells from ZEN, α- and β-ZOL-induced toxicity.

  18. Autophagy, stress, and cancer metabolism: what doesn't kill you makes you stronger.

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    Mathew, R; White, E

    2011-01-01

    Altered metabolism is a hallmark of cancer. Oncogenic events that lead to cancerous states reorganize metabolic pathways to increase nutrient uptake, which promotes biosynthetic capabilities and cell-autonomous behavior. Increased biosynthesis dictates metabolic demand for ATP, building blocks, and reducing equivalents, rendering cancer cells metabolically in a perpetually hungry state. Moreover, most chemotherapy agents induce acute metabolic stress that cancer cells must overcome for their survival. These metabolic stress cues in cancer cells can activate and cause dependence on the self-cannibalization mechanism of macroautophagy (autophagy hereafter) for the lysosomal turnover and recycling of organelles and proteins for energy and stress survival. For example, activating mutations in Ras or Ras-effector pathways induce autophagy, and cancer cell lines with Ras activation show elevated levels of basal autophagy that is essential for starvation survival and tumor growth. The metabolic implications of this are profound and multifaceted. First, autophagy-mediated degradation and recycling of cellular substrates can support metabolism and promote survival and tumor growth. Second, acute autophagy activation in response to cancer therapy can potentially lead to refractory tumors resistant to conventional chemotherapy. For example, a specific form of autophagy that targets mitochondria (mitophagy) may also function to promote cell survival by the clearance of damaged mitochondria that are potential sources of reactive oxygen species (ROS). These point to the possibility that autophagy is a unique metabolic need, important for survival as well as therapy resistance in cancer cells. Targeting autophagy in single-agent therapy to sensitize aggressive cancers that are dependent on autophagy for survival or in combination with therapeutic agents that induce autophagy as a resistance mechanism may be an effective therapeutic strategy to treat cancer.

  19. 2-Deoxy-D-glucose treatment of endothelial cells induces autophagy by reactive oxygen species-mediated activation of the AMP-activated protein kinase.

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    Qilong Wang

    2011-02-01

    Full Text Available Autophagy is a cellular self-digestion process activated in response to stresses such as energy deprivation and oxidative stress. However, the mechanisms by which energy deprivation and oxidative stress trigger autophagy remain undefined. Here, we report that activation of AMP-activated protein kinase (AMPK by mitochondria-derived reactive oxygen species (ROS is required for autophagy in cultured endothelial cells. AMPK activity, ROS levels, and the markers of autophagy were monitored in confluent bovine aortic endothelial cells (BAEC treated with the glycolysis blocker 2-deoxy-D-glucose (2-DG. Treatment of BAEC with 2-DG (5 mM for 24 hours or with low concentrations of H(2O(2 (100 µM induced autophagy, including increased conversion of microtubule-associated protein light chain 3 (LC3-I to LC3-II, accumulation of GFP-tagged LC3 positive intracellular vacuoles, and increased fusion of autophagosomes with lysosomes. 2-DG-treatment also induced AMPK phosphorylation, which was blocked by either co-administration of two potent anti-oxidants (Tempol and N-Acetyl-L-cysteine or overexpression of superoxide dismutase 1 or catalase in BAEC. Further, 2-DG-induced autophagy in BAEC was blocked by overexpressing catalase or siRNA-mediated knockdown of AMPK. Finally, pretreatment of BAEC with 2-DG increased endothelial cell viability after exposure to hypoxic stress. Thus, AMPK is required for ROS-triggered autophagy in endothelial cells, which increases endothelial cell survival in response to cell stress.

  20. Green Tea Polyphenols, Mimicking the Effects of Dietary Restriction, Ameliorate High-Fat Diet-Induced Kidney Injury via Regulating Autophagy Flux

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    Xiao Xie

    2017-05-01

    Full Text Available Epidemiological and experimental studies reveal that Western dietary patterns contribute to chronic kidney disease, whereas dietary restriction (DR or dietary polyphenols such as green tea polyphenols (GTPs can ameliorate the progression of kidney injury. This study aimed to investigate the renal protective effects of GTPs and explore the underlying mechanisms. Sixty Wistar rats were randomly divided into 6 groups: standard diet (STD, DR, high-fat diet (HFD, and three diets plus 200 mg/kg(bw/day GTPs, respectively. After 18 weeks, HFD group exhibited renal injuries by increased serum cystatin C levels and urinary N-acetyl-β-d-glucosaminidase activity, which can be ameliorated by GTPs. Meanwhile, autophagy impairment as denoted by autophagy-lysosome related proteins, including LC3-II, Beclin-1, p62, cathepsin B, cathepsin D and LAMP-1, was observed in HFD group, whereas DR or GTPs promoted renal autophagy activities and GTPs ameliorated HFD-induced autophagy impairment. In vitro, autophagy flux suppression was detected in palmitic acid (PA-treated human proximal tubular epithelial cells (HK-2, which was ameliorated by epigallocatechin-3-gallate (EGCG. Furthermore, GTPs (or EGCG elevated phosphorylation of AMP-activated protein kinase in the kidneys of HFD-treated rats and in PA-treated HK-2 cells. These findings revealed that GTPs mimic the effects of DR to induce autophagy and exert a renal protective effect by alleviating HFD-induced autophagy suppression.

  1. Lutein Attenuates Both Apoptosis and Autophagy upon Cobalt (II) Chloride-Induced Hypoxia in Rat Műller Cells.

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    Fung, Frederic K C; Law, Betty Y K; Lo, Amy C Y

    2016-01-01

    Retinal ischemia/reperfusion injury is a common feature of various retinal diseases such as glaucoma and diabetic retinopathy. Lutein, a potent anti-oxidant, is used to improve visual function in patients with age-related macular degeneration (AMD). Lutein attenuates apoptosis, oxidative stress and inflammation in animal models of acute retinal ischemia/hypoxia. Here, we further show that lutein improved Műller cell viability and enhanced cell survival upon hypoxia-induced cell death through regulation of intrinsic apoptotic pathway. Moreover, autophagy was activated upon treatment of cobalt (II) chloride, indicating that hypoxic injury not only triggered apoptosis but also autophagy in our in vitro model. Most importantly, we report for the first time that lutein treatment suppressed autophagosome formation after hypoxic insult and lutein administration could inhibit autophagic event after activation of autophagy by a pharmacological approach (rapamycin). Taken together, lutein may have a beneficial role in enhancing glial cell survival after hypoxic injury through regulating both apoptosis and autophagy.

  2. Extracellular acidification by lactic acid suppresses glucose deprivation-induced cell death and autophagy in B16 melanoma cells.

    Science.gov (United States)

    Matsuo, Taisuke; Sadzuka, Yasuyuki

    2018-02-19

    In solid tumors, cancer cells survive and proliferate under conditions of microenvironment stress such as poor nutrients and hypoxia due to inadequate vascularization. These stress conditions in turn activate autophagy, which is important for cancer cell survival. However, autophagy has a contrary effect of inducing cell death in cancer cells cultured in vitro under conditions of glucose deprivation. In this study, we hypothesized that supplementation of lactic acid serves as a means of cell survival under glucose-deprived conditions. At neutral pH, cell death of B16 murine melanoma cells by autophagy under glucose-deprived conditions was observed. However, supplementation of lactic acid suppressed cell death and autophagy in B16 melanoma cells when cultured in glucose-deprived conditions. Sodium lactate, which does not change extracellular pH, did not inhibit cell death, while HCl-adjusted acidic pH suppressed cell death under glucose-deprived conditions. These results suggested that an acidic pH is crucial for cell survival under glucose-deprived conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. IFN-gamma-inducible Irga6 mediates host resistance against Chlamydia trachomatis via autophagy.

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    Munir A Al-Zeer

    Full Text Available Chlamydial infection of the host cell induces Gamma interferon (IFNgamma, a central immunoprotector for humans and mice. The primary defense against Chlamydia infection in the mouse involves the IFNgamma-inducible family of IRG proteins; however, the precise mechanisms mediating the pathogen's elimination are unknown. In this study, we identify Irga6 as an important resistance factor against C. trachomatis, but not C. muridarum, infection in IFNgamma-stimulated mouse embryonic fibroblasts (MEFs. We show that Irga6, Irgd, Irgm2 and Irgm3 accumulate at bacterial inclusions in MEFs upon stimulation with IFNgamma, whereas Irgb6 colocalized in the presence or absence of the cytokine. This accumulation triggers a rerouting of bacterial inclusions to autophagosomes that subsequently fuse to lysosomes for elimination. Autophagy-deficient Atg5-/- MEFs and lysosomal acidification impaired cells surrender to infection. Irgm2, Irgm3 and Irgd still localize to inclusions in IFNgamma-induced Atg5-/- cells, but Irga6 localization is disrupted indicating its pivotal role in pathogen resistance. Irga6-deficient (Irga6-/- MEFs, in which chlamydial growth is enhanced, do not respond to IFNgamma even though Irgb6, Irgd, Irgm2 and Irgm3 still localize to inclusions. Taken together, we identify Irga6 as a necessary factor in conferring host resistance by remodelling a classically nonfusogenic intracellular pathogen to stimulate fusion with autophagosomes, thereby rerouting the intruder to the lysosomal compartment for destruction.

  4. Andrographolide Induces Autophagic Cell Death and Inhibits Invasion and Metastasis of Human Osteosarcoma Cells in An Autophagy-Dependent Manner

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    Ying Liu

    2017-11-01

    Full Text Available Background/Aims: Osteosarcoma (OS is the most common primary malignant tumor of bone tissue. Although treatment effectiveness has improved, the OS survival rate has fluctuated in recent years. Andrographolide (AG has been reported to have antitumor activity against a variety of tumors. Our aim was to investigate the effects and potential mechanisms of AG in human osteosarcoma. Methods: Cell viability and morphological changes were assessed by MTT and live/dead assays. Apoptosis was detected using Annexin V-FITC/PI double staining, DAPI, and caspase-3 assays. Autophagy was detected with mRFP-GFP-LC3 adenovirus transfection and western blot. Cell migration and invasion were detected by wound healing assay and Transwell® experiments. Results: AG dose-dependently reduced the viability of osteosarcoma cells. No increase in apoptosis was detected in AG-treated human OS MG-63 and U-2OS cells, and the pan-caspase inhibitor z-VAD did not attenuate AG-induced cell death. However, AG induced autophagy by suppressing PI3K/Akt/mTOR and enhancing JNK signaling pathways. 3-MA and Beclin-1 siRNA could reverse the cytotoxic effects of AG. In addition, AG inhibited the invasion and metastasis of OS, and this effect could be reversed with Beclin-1 siRNA. Conclusion: AG inhibits viability and induces autophagic death in OS cells. AG-induced autophagy inhibits the invasion and metastasis of OS.

  5. Andrographolide Induces Autophagic Cell Death and Inhibits Invasion and Metastasis of Human Osteosarcoma Cells in An Autophagy-Dependent Manner.

    Science.gov (United States)

    Liu, Ying; Zhang, Yan; Zou, Jilong; Yan, Lixin; Yu, Xiufeng; Lu, Peng; Wu, Xiaomeng; Li, Qiaozhi; Gu, Rui; Zhu, Daling

    2017-01-01

    Osteosarcoma (OS) is the most common primary malignant tumor of bone tissue. Although treatment effectiveness has improved, the OS survival rate has fluctuated in recent years. Andrographolide (AG) has been reported to have antitumor activity against a variety of tumors. Our aim was to investigate the effects and potential mechanisms of AG in human osteosarcoma. Cell viability and morphological changes were assessed by MTT and live/dead assays. Apoptosis was detected using Annexin V-FITC/PI double staining, DAPI, and caspase-3 assays. Autophagy was detected with mRFP-GFP-LC3 adenovirus transfection and western blot. Cell migration and invasion were detected by wound healing assay and Transwell® experiments. AG dose-dependently reduced the viability of osteosarcoma cells. No increase in apoptosis was detected in AG-treated human OS MG-63 and U-2OS cells, and the pan-caspase inhibitor z-VAD did not attenuate AG-induced cell death. However, AG induced autophagy by suppressing PI3K/Akt/mTOR and enhancing JNK signaling pathways. 3-MA and Beclin-1 siRNA could reverse the cytotoxic effects of AG. In addition, AG inhibited the invasion and metastasis of OS, and this effect could be reversed with Beclin-1 siRNA. AG inhibits viability and induces autophagic death in OS cells. AG-induced autophagy inhibits the invasion and metastasis of OS. © 2017 The Author(s). Published by S. Karger AG, Basel.

  6. Axonal protection by short-term hyperglycemia with involvement of autophagy in TNF-induced optic nerve degeneration

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    Kana eSase

    2015-10-01

    Full Text Available Previous reports showed that short-term hyperglycemia protects optic nerve axons in a rat experimental hypertensive glaucoma model. In this study, we investigated whether short-term hyperglycemia prevents tumor necrosis factor (TNF-induced optic nerve degeneration in rats and examined the role of autophagy in this axon change process. In phosphate-buffered saline-treated rat eyes, no significant difference in axon number between the normoglycemic (NG and streptozotocin-induced hyperglycemic (HG groups was seen at 2weeks. Substantial degenerative changes in the axons were noted 2 weeks after intravitreal injection of TNF in the NG group. However, the HG group showed significant protective effects on axons against TNF-induced optic nerve degeneration compared with the NG group. This protective effect was significantly inhibited by 3-methyladenine, an autophagy inhibitor. Immunoblot analysis showed that the LC3-II level in the optic nerve was increased in the HG group compared with the NG group. Increased p62 protein levels in the optic nerve after TNF injection was observed in the NG group, and this increase was inhibited in the HG group. Electron microscopy showed that autophagosomes were increased in optic nerve axons in the HG group. Immunohistochemical study showed that LC3 was colocalized with nerve fibers in the retina and optic nerve in both the NG and HG groups. Short-term hyperglycemia protects axons against TNF-induced optic nerve degeneration. This axonal-protective effect may be associated with autophagy machinery.

  7. AMP-activated protein kinase deficiency rescues paraquat-induced cardiac contractile dysfunction through an autophagy-dependent mechanism.

    Science.gov (United States)

    Wang, Qiurong; Yang, Lifang; Hua, Yinan; Nair, Sreejayan; Xu, Xihui; Ren, Jun

    2014-11-01

    Paraquat, a quaternary nitrogen herbicide, is a highly toxic prooxidant resulting in multi-organ failure including the heart although the underlying mechanism still remains elusive. This study was designed to examine the role of the cellular fuel sensor AMP-activated protein kinase (AMPK) in paraquat-induced cardiac contractile and mitochondrial injury. Wild-type and transgenic mice with overexpression of a mutant AMPK α2 subunit (kinase dead, KD), with reduced activity in both α1 and α2 subunits, were administered with paraquat (45 mg/kg) for 48 h. Paraquat elicited cardiac mechanical anomalies including compromised echocardiographic parameters (elevated left ventricular end-systolic diameter and reduced factional shortening), suppressed cardiomyocyte contractile function, intracellular Ca(2+) handling, reduced cell survival, and overt mitochondrial damage (loss in mitochondrial membrane potential). In addition, paraquat treatment promoted phosphorylation of AMPK and autophagy. Interestingly, deficiency in AMPK attenuated paraquat-induced cardiac contractile and intracellular Ca(2+) derangement. The beneficial effect of AMPK inhibition was associated with inhibition of the AMPK-TSC-mTOR-ULK1 signaling cascade. In vitro study revealed that inhibitors for AMPK and autophagy attenuated paraquat-induced cardiomyocyte contractile dysfunction. Taken together, our findings revealed that AMPK may mediate paraquat-induced myocardial anomalies possibly by regulating the AMPK/mTOR-dependent autophagy. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  8. Salinomycin activates AMP-activated protein kinase-dependent autophagy in cultured osteoblastoma cells: a negative regulator against cell apoptosis.

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    Lun-qing Zhu

    Full Text Available The malignant osteoblastoma has poor prognosis, thus the search for novel and more efficient chemo-agents against this disease is urgent. Salinomycin induces broad anti-cancer effects both in vivo and in vitro, however, its role in osteoblastoma is still not clear.Salinomycin induced both apoptosis and autophagy in cultured U2OS and MG-63 osteoblastoma cells. Inhibition of autophagy by 3-methyladenine (3-MA, or by RNA interference (RNAi of light chain 3B (LC3B, enhanced salinomycin-induced cytotoxicity and apoptosis. Salinomycin induced a profound AMP-activated protein kinase (AMPK activation, which was required for autophagy induction. AMPK inhibition by compound C, or by AMPKα RNAi prevented salinomycin-induced autophagy activation, while facilitating cancer cell death and apoptosis. On the other hand, the AMPK agonist AICAR promoted autophagy activation in U2OS cells. Salinomycin-induced AMPK activation was dependent on reactive oxygen species (ROS production in osteoblastoma cells. Antioxidant n-acetyl cysteine (NAC significantly inhibited salinomycin-induced AMPK activation and autophagy induction.Salinomycin activates AMPK-dependent autophagy in osteoblastoma cells, which serves as a negative regulator against cell apoptosis. AMPK-autophagy inhibition might be a novel strategy to sensitize salinomycin's effect in cancer cells.

  9. Salinomycin activates AMP-activated protein kinase-dependent autophagy in cultured osteoblastoma cells: a negative regulator against cell apoptosis.

    Science.gov (United States)

    Zhu, Lun-qing; Zhen, Yun-fang; Zhang, Ya; Guo, Zhi-xiong; Dai, Jin; Wang, Xiao-dong

    2013-01-01

    The malignant osteoblastoma has poor prognosis, thus the search for novel and more efficient chemo-agents against this disease is urgent. Salinomycin induces broad anti-cancer effects both in vivo and in vitro, however, its role in osteoblastoma is still not clear. Salinomycin induced both apoptosis and autophagy in cultured U2OS and MG-63 osteoblastoma cells. Inhibition of autophagy by 3-methyladenine (3-MA), or by RNA interference (RNAi) of light chain 3B (LC3B), enhanced salinomycin-induced cytotoxicity and apoptosis. Salinomycin induced a profound AMP-activated protein kinase (AMPK) activation, which was required for autophagy induction. AMPK inhibition by compound C, or by AMPKα RNAi prevented salinomycin-induced autophagy activation, while facilitating cancer cell death and apoptosis. On the other hand, the AMPK agonist AICAR promoted autophagy activation in U2OS cells. Salinomycin-induced AMPK activation was dependent on reactive oxygen species (ROS) production in osteoblastoma cells. Antioxidant n-acetyl cysteine (NAC) significantly inhibited salinomycin-induced AMPK activation and autophagy induction. Salinomycin activates AMPK-dependent autophagy in osteoblastoma cells, which serves as a negative regulator against cell apoptosis. AMPK-autophagy inhibition might be a novel strategy to sensitize salinomycin's effect in cancer cells.

  10. Salinomycin Activates AMP-Activated Protein Kinase-Dependent Autophagy in Cultured Osteoblastoma Cells: A Negative Regulator against Cell Apoptosis

    Science.gov (United States)

    Zhang, Ya; Guo, Zhi-xiong; Dai, Jin; Wang, Xiao-dong

    2013-01-01

    Background The malignant osteoblastoma has poor prognosis, thus the search for novel and more efficient chemo-agents against this disease is urgent. Salinomycin induces broad anti-cancer effects both in vivo and in vitro, however, its role in osteoblastoma is still not clear. Key Findings Salinomycin induced both apoptosis and autophagy in cultured U2OS and MG-63 osteoblastoma cells. Inhibition of autophagy by 3-methyladenine (3-MA), or by RNA interference (RNAi) of light chain 3B (LC3B), enhanced salinomycin-induced cytotoxicity and apoptosis. Salinomycin induced a profound AMP-activated protein kinase (AMPK) activation, which was required for autophagy induction. AMPK inhibition by compound C, or by AMPKα RNAi prevented salinomycin-induced autophagy activation, while facilitating cancer cell death and apoptosis. On the other hand, the AMPK agonist AICAR promoted autophagy activation in U2OS cells. Salinomycin-induced AMPK activation was dependent on reactive oxygen species (ROS) production in osteoblastoma cells. Antioxidant n-acetyl cysteine (NAC) significantly inhibited salinomycin-induced AMPK activation and autophagy induction. Conclusions Salinomycin activates AMPK-dependent autophagy in osteoblastoma cells, which serves as a negative regulator against cell apoptosis. AMPK-autophagy inhibition might be a novel strategy to sensitize salinomycin’s effect in cancer cells. PMID:24358342

  11. Role of D-Limonene in Autophagy Induced by Bergamot Essential Oil in SH-SY5Y Neuroblastoma Cells

    Science.gov (United States)

    Russo, Rossella; Cassiano, Maria Gilda Valentina; Ciociaro, Antonella; Adornetto, Annagrazia; Varano, Giuseppe Pasquale; Chiappini, Carlotta; Berliocchi, Laura; Tassorelli, Cristina; Bagetta, Giacinto; Corasaniti, Maria Tiziana

    2014-01-01

    Bergamot (Citrus bergamia, Risso et Poiteau) essential oil (BEO) is a well characterized, widely used plant extract. BEO exerts anxiolytic, analgesic and neuroprotective activities in rodents through mechanisms that are only partly known and need to be further investigated. To gain more insight into the biological effects of this essential oil, we tested the ability of BEO (0.005–0.03%) to modulate autophagic pathways in human SH-SY5Y neuroblastoma cells. BEO-treated cells show increased LC3II levels and appearance of dot-like formations of endogenous LC3 protein that colocalize with the lysosome marker LAMP-1. Autophagic flux assay using bafilomycin A1 and degradation of the specific autophagy substrate p62 confirmed that the observed increase of LC3II levels in BEO-exposed cells is due to autophagy induction rather than to a decreased autophagosomal turnover. Induction of autophagy is an early and not cell-line specific response to BEO. Beside basal autophagy, BEO also enhanced autophagy triggered by serum starvation and rapamycin indicating that the underlying mechanism is mTOR independent. Accordingly, BEO did not affect the phosphorylation of ULK1 (Ser757) and p70S6K (Thr389), two downstream targets of mTOR. Furthermore, induction of autophagy by BEO is beclin-1 independent, occurs in a concentration-dependent manner and is unrelated to the ability of BEO to induce cell death. In order to identify the active constituents responsible for these effects, the two most abundant monoterpenes found in the essential oil, d-limonene (125–750 µM) and linalyl acetate (62.5–375 µM), were individually tested at concentrations comparable to those found in 0.005–0.03% BEO. The same features of stimulated autophagy elicited by BEO were reproduced by d-limonene, which rapidly increases LC3II and reduces p62 levels in a concentration-dependent manner. Linalyl acetate was ineffective in replicating BEO effects; however, it greatly enhanced LC3 lipidation triggered by d

  12. Regorafenib impairs mitochondrial functions, activates AMP-activated protein kinase, induces autophagy, and causes rat hepatocyte necrosis.

    Science.gov (United States)

    Weng, Zuquan; Luo, Yong; Yang, Xi; Greenhaw, James J; Li, Haibo; Xie, Liming; Mattes, William B; Shi, Qiang

    2015-01-02

    The tyrosine kinase inhibitor regorafenib was approved by regulatory agencies for cancer treatment, albeit with strong warnings of severe hepatotoxicity included in the product label. The basis of this toxicity is unknown; one possible mechanism, that of mitochondrial damage, was tested. In isolated rat liver mitochondria, regorafenib directly uncoupled oxidative phosphorylation (OXPHOS) and promoted calcium overload-induced swelling, which were respectively prevented by the recoupler 6-ketocholestanol (KC) and the mitochondrial permeability transition (MPT) pore blocker cyclosporine A (CsA). In primary hepatocytes, regorafenib uncoupled OXPHOS, disrupted mitochondrial inner membrane potential (MMP), and decreased cellular ATP at 1h, and triggered MPT at 3h, which was followed by necrosis but not apoptosis at 7h and 24h, all of which were abrogated by KC. The combination of the glycolysis enhancer fructose plus the mitochondrial ATPase synthase inhibitor oligomycin A abolished regorafenib induced necrosis at 7h. This effect was not seen at 24h nor with the fructose or oligomycin A separately. CsA in combination with trifluoperazine, both MPT blockers, showed similar effects. Two compensatory mechanisms, activation of AMP-activated protein kinase (AMPK) to ameliorate ATP shortage and induction of autophagy to remove dysfunctional mitochondria, were found to be mobilized. Hepatocyte necrosis was enhanced either by the AMPK inhibitor Compound C or the autophagy inhibitor chloroquine, while autophagy inducer rapamycin was strongly cytoprotective. Remarkably, all toxic effects were observed at clinically-relevant concentrations of 2.5-15μM. These data suggest that uncoupling of OXPHOS and the resulting ATP shortage and MPT induction are the key mechanisms for regorafenib induced hepatocyte injury, and AMPK activation and autophagy induction serve as pro-survival pathways against such toxicity. Published by Elsevier Ireland Ltd.

  13. A combination of indol-3-carbinol and genistein synergistically induces apoptosis in human colon cancer HT-29 cells by inhibiting Akt phosphorylation and progression of autophagy

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    Watanabe Hirotsuna

    2009-11-01

    Full Text Available Abstract Background The chemopreventive effects of dietary phytochemicals on malignant tumors have been studied extensively because of a relative lack of toxicity. To achieve desirable effects, however, treatment with a single agent mostly requires high doses. Therefore, studies on effective combinations of phytochemicals at relatively low concentrations might contribute to chemopreventive strategies. Results Here we found for the first time that co-treatment with I3C and genistein, derived from cruciferous vegetables and soy, respectively, synergistically suppressed the viability of human colon cancer HT-29 cells at concentrations at which each agent alone was ineffective. The suppression of cell viability was due to the induction of a caspase-dependent apoptosis. Moreover, the combination effectively inhibited phosphorylation of Akt followed by dephosphorylation of caspase-9 or down-regulation of XIAP and survivin, which contribute to the induction of apoptosis. In addition, the co-treatment also enhanced the induction of autophagy mediated by the dephosphorylation of mTOR, one of the downstream targets of Akt, whereas the maturation of autophagosomes was inhibited. These results give rise to the possibility that co-treatment with I3C and genistein induces apoptosis through the simultaneous inhibition of Akt activity and progression of the autophagic process. This possibility was examined using inhibitors of Akt combined with inhibitors of autophagy. The combination effectively induced apoptosis, whereas the Akt inhibitor alone did not. Conclusion Although in vivo study is further required to evaluate physiological efficacies and toxicity of the combination treatment, our findings might provide a new insight into the development of novel combination therapies/chemoprevention against malignant tumors using dietary phytochemicals.

  14. Alisertib Induces Cell Cycle Arrest, Apoptosis, Autophagy and Suppresses EMT in HT29 and Caco-2 Cells

    Science.gov (United States)

    Ren, Bao-Jun; Zhou, Zhi-Wei; Zhu, Da-Jian; Ju, Yong-Le; Wu, Jin-Hao; Ouyang, Man-Zhao; Chen, Xiao-Wu; Zhou, Shu-Feng

    2015-01-01

    Colorectal cancer (CRC) is one of the most common malignancies worldwide with substantial mortality and morbidity. Alisertib (ALS) is a selective Aurora kinase A (AURKA) inhibitor with unclear effect and molecular interactome on CRC. This study aimed to evaluate the molecular interactome and anticancer effect of ALS and explore the underlying mechanisms in HT29 and Caco-2 cells. ALS markedly arrested cells in G2/M phase in both cell lines, accompanied by remarkable alterations in the expression level of key cell cycle regulators. ALS induced apoptosis in HT29 and Caco-2 cells through mitochondrial and death receptor pathways. ALS also induced autophagy in HT29 and Caco-2 cells, with the suppression of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR), but activation of 5′ AMP-activated protein kinase (AMPK) signaling pathways. There was a differential modulating effect of ALS on p38 MAPK signaling pathway in both cell lines. Moreover, induction or inhibition of autophagy modulated basal and ALS-induced apoptosis in both cell lines. ALS potently suppressed epithelial to mesenchymal transition (EMT) in HT29 and Caco-2 cells. Collectively, it suggests that induction of cell cycle arrest, promotion of apoptosis and autophagy, and suppression of EMT involving mitochondrial, death receptor, PI3K/Akt/mTOR, p38 MAPK, and AMPK signaling pathways contribute to the cancer cell killing effect of ALS on CRC cells. PMID:26729093

  15. Nrf2 signalling and autophagy are involved in diabetes mellitus-induced defects in the development of mouse placenta

    Science.gov (United States)

    Han, Sha-sha; Jin, Ya; Li, He; Wu, Xia; Ma, Zheng-lai; cheng, Xin; Tang, Xiuwen

    2016-01-01

    It is widely accepted that diabetes mellitus impairs placental development, but the mechanism by which the disease operates to impair development remains controversial. In this study, we demonstrated that pregestational diabetes mellitus (PGDM)-induced defects in placental development in mice are mainly characterized by the changes of morphological structure of placenta. The alteration of differentiation-related gene expressions in trophoblast cells rather than cell proliferation/apoptosis is responsible for the phenotypes found in mouse placenta. Meanwhile, excess reactive oxygen species (ROS) production and activated nuclear factor erythroid2-related factor 2 (Nrf2) signalling were observed in the placenta of mice suffering from PGDM. Using BeWo cells, we also demonstrated that excess ROS was produced and Nrf2 signalling molecules were activated in settings characterized by a high concentration of glucose. More interestingly, differentiation-related gene expressions in trophoblast cells were altered when endogenous Nrf2 expression is manipulated by transfecting Nrf2-wt or Nrf2-shRNA. In addition, PGDM interferes with autophagy in both mouse placenta and BeWo cells, implying that autophagy is also involved, directly or indirectly, in PGDM-induced placental phenotypes. Therefore, we revealed that dysfunctional oxidative stress-activated Nrf2 signalling and autophagy are probably responsible for PGDM-induced defects in the placental development of mice. The mechanism was through the interference with differentiation-related gene expression in trophoblast cells. PMID:27383629

  16. Alisertib Induces Cell Cycle Arrest, Apoptosis, Autophagy and Suppresses EMT in HT29 and Caco-2 Cells

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    Bao-Jun Ren

    2015-12-01

    Full Text Available Colorectal cancer (CRC is one of the most common malignancies worldwide with substantial mortality and morbidity. Alisertib (ALS is a selective Aurora kinase A (AURKA inhibitor with unclear effect and molecular interactome on CRC. This study aimed to evaluate the molecular interactome and anticancer effect of ALS and explore the underlying mechanisms in HT29 and Caco-2 cells. ALS markedly arrested cells in G2/M phase in both cell lines, accompanied by remarkable alterations in the expression level of key cell cycle regulators. ALS induced apoptosis in HT29 and Caco-2 cells through mitochondrial and death receptor pathways. ALS also induced autophagy in HT29 and Caco-2 cells, with the suppression of phosphoinositide 3-kinase (PI3K/protein kinase B (Akt/mammalian target of rapamycin (mTOR, but activation of 5′ AMP-activated protein kinase (AMPK signaling pathways. There was a differential modulating effect of ALS on p38 MAPK signaling pathway in both cell lines. Moreover, induction or inhibition of autophagy modulated basal and ALS-induced apoptosis in both cell lines. ALS potently suppressed epithelial to mesenchymal transition (EMT in HT29 and Caco-2 cells. Collectively, it suggests that induction of cell cycle arrest, promotion of apoptosis and autophagy, and suppression of EMT involving mitochondrial, death receptor, PI3K/Akt/mTOR, p38 MAPK, and AMPK signaling pathways contribute to the cancer cell killing effect of ALS on CRC cells.

  17. Irradiation With Carbon Ion Beams Induces Apoptosis, Autophagy, and Cellular Senescence in a Human Glioma-Derived Cell Line

    International Nuclear Information System (INIS)

    Jinno-Oue, Atsushi; Shimizu, Nobuaki; Hamada, Nobuyuki; Wada, Seiichi; Tanaka, Atsushi; Shinagawa, Masahiko; Ohtsuki, Takahiro; Mori, Takahisa; Saha, Manujendra N.; Hoque, Ariful S.; Islam, Salequl; Kogure, Kimitaka; Funayama, Tomoo; Kobayashi, Yasuhiko

    2010-01-01

    Purpose: We examined biological responses of human glioma cells to irradiation with carbon ion beams (C-ions). Methods and Materials: A human glioma-derived cell line, NP-2, was irradiated with C-ions. Apoptotic cell nuclei were stained with Hoechst 33342. Induction of autophagy was examined either by staining cells with monodansylcadaverine (MDC) or by Western blotting to detect conversion of microtuble-associated protein light chain 3 (MAP-LC3) (LC3-I) to the membrane-bound form (LC3-II). Cellular senescence markers including induction of senescence-associated β-galactosidase (SA-β-gal) were examined. The mean telomere length of irradiated cells was determined by Southern blot hybridization. Expression of tumor suppressor p53 and cyclin/cyclin-dependent kinase inhibitor p21 WAF1/CIP1 in the irradiated cells was analyzed by Western blotting. Results: When NP-2 cells were irradiated with C-ions at 6 Gy, the major population of the cells died of apoptosis and autophagy. The residual fraction of attached cells ( WAF1/CIP1 was induced in NP-2 cells after irradiation. Furthermore, we found that irradiation with C-ions induced cellular senescence in a human glioma cell line lacking functional p53. Conclusions: Irradiation with C-ions induced apoptosis, autophagy, and cellular senescence in human glioma cells.

  18. Fluoride-Induced Autophagy via the Regulation of Phosphorylation of Mammalian Targets of Rapamycin in Mice Leydig Cells.

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    Zhang, Jianhai; Zhu, Yuchen; Shi, Yan; Han, Yongli; Liang, Chen; Feng, Zhiyuan; Zheng, Heping; Eng, Michelle; Wang, Jundong

    2017-10-11

    Fluoride is known to impair testicular function and decrease testosterone levels, yet the underlying mechanisms remain inconclusive. The objective of this study is to investigate the roles of autophagy in fluoride-induced male reproductive toxicity using both in vivo and in vitro Leydig cell models. Using transmission electron microscopy and monodansylcadaverine staining, we observed increasing numbers of autophagosomes in testicular tissue, especially in Leydig cells of fluoride-exposed mice. Further study revealed that fluoride increased the levels of mRNA and protein expression of autophagy markers LC3, Beclin1, and Atg 5 in primary Leydig cells. Furthermore, fluoride inhibited the phosphorylation of mammalian targets of rapamycin and 4EBP1, which in turn resulted in a decrease in the levels of AKT and PI3K mRNA expression, as well as an elevation of the level of AMPK expression in both testes and primary Leydig cells. Additionally, fluoride exposure significantly changed the mRNA expression of the PDK1, TSC, and Atg13 regulator genes in primary Leydig cells but not in testicular cells. Taken together, our findings highlight the roles of autophagy in fluoride-induced testicular and Leydig cell damage and contribute to the elucidation of the underlying mechanisms of fluoride-induced male reproductive toxicity.

  19. Short Telomeres Induce p53 and Autophagy and Modulate Age-Associated Changes in Cardiac Progenitor Cell Fate.

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    Matsumoto, Collin; Jiang, Yan; Emathinger, Jacqueline; Quijada, Pearl; Nguyen, Nathalie; De La Torre, Andrea; Moshref, Maryam; Nguyen, Jonathan; Levinson, Aimee B; Shin, Minyoung; Sussman, Mark A; Hariharan, Nirmala

    2018-02-14

    Aging severely limits myocardial repair and regeneration. Delineating the impact of age-associated factors such as short telomeres is critical to enhance the regenerative potential of cardiac progenitor cells (CPCs). We hypothesized that short telomeres activate p53 and induce autophagy to elicit the age-associated change in CPC fate. We isolated CPCs and compared mouse strains with different telomere lengths for phenotypic characteristics of aging. Wild mouse strain Mus musculus castaneus (CAST) possessing short telomeres exhibits early cardiac aging with cardiac dysfunction, hypertrophy, fibrosis, and senescence, as compared with common lab strains FVB and C57 bearing longer telomeres. CAST CPCs with short telomeres demonstrate altered cell fate as characterized by cell cycle arrest, senescence, basal commitment, and loss of quiescence. Elongation of telomeres using a modified mRNA for telomerase restores youthful properties to CAST CPCs. Short telomeres induce autophagy in CPCs, a catabolic protein degradation process, as evidenced by reduced p62 and increased accumulation of autophagic puncta. Pharmacological inhibition of autophagosome formation reverses the cell fate to a more youthful phenotype. Mechanistically, cell fate changes induced by short telomeres are partially p53 dependent, as p53 inhibition rescues senescence and commitment observed in CAST CPCs, coincident with attenuation of autophagy. In conclusion, short telomeres activate p53 and autophagy to tip the equilibrium away from quiescence and proliferation toward differentiation and senescence, leading to exhaustion of CPCs. This study provides the mechanistic basis underlying age-associated cell fate changes that will enable identification of molecular strategies to prevent senescence of CPCs. Stem Cells 2018. © AlphaMed Press 2018.

  20. Protein tyrosine phosphatase non-receptor type 22 modulates NOD2-induced cytokine release and autophagy.

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    Marianne R Spalinger

    Full Text Available BACKGROUND: Variations within the gene locus encoding protein tyrosine phosphatase non-receptor type 22 (PTPN22 are associated with the risk to develop inflammatory bowel disease (IBD. PTPN22 is involved in the regulation of T- and B-cell receptor signaling, but although it is highly expressed in innate immune cells, its function in other signaling pathways is less clear. Here, we study whether loss of PTPN22 controls muramyl-dipeptide (MDP-induced signaling and effects in immune cells. MATERIAL & METHODS: Stable knockdown of PTPN22 was induced in THP-1 cells by shRNA transduction prior to stimulation with the NOD2 ligand MDP. Cells were analyzed for signaling protein activation and mRNA expression by Western blot and quantitative PCR; cytokine secretion was assessed by ELISA, autophagosome induction by Western blot and immunofluorescence staining. Bone marrow derived dendritic cells (BMDC were obtained from PTPN22 knockout mice or wild-type animals. RESULTS: MDP-treatment induced PTPN22 expression and activity in human and mouse cells. Knockdown of PTPN22 enhanced MDP-induced activation of mitogen-activated protein kinase (MAPK-isoforms p38 and c-Jun N-terminal kinase as well as canonical NF-κB signaling molecules in THP-1 cells and BMDC derived from PTPN22 knockout mice. Loss of PTPN22 enhanced mRNA levels and secretion of interleukin (IL-6, IL-8 and TNF in THP-1 cells and PTPN22 knockout BMDC. Additionally, loss of PTPN22 resulted in increased, MDP-mediated autophagy in human and mouse cells. CONCLUSIONS: Our data demonstrate that PTPN22 controls NOD2 signaling, and loss of PTPN22 renders monocytes more reactive towards bacterial products, what might explain the association of PTPN22 variants with IBD pathogenesis.

  1. Bitter taste receptor agonists alter mitochondrial function and induce autophagy in airway smooth muscle cells.

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    Pan, Shi; Sharma, Pawan; Shah, Sushrut D; Deshpande, Deepak A

    2017-07-01

    Airway remodeling, including increased airway smooth muscle (ASM) mass, is a hallmark feature of asthma and COPD. We previously identified the expression of bitter taste receptors (TAS2Rs) on human ASM cells and demonstrated that known TAS2R agonists could promote ASM relaxation and bronchodilation and inhibit mitogen-induced ASM growth. In this study, we explored cellular mechanisms mediating the antimitogenic effect of TAS2R agonists on human ASM cells. Pretreatment of ASM cells with TAS2R agonists chloroquine and quinine resulted in inhibition of cell survival, which was largely reversed by bafilomycin A1, an autophagy inhibitor. Transmission electron microscope studies demonstrated the presence of double-membrane autophagosomes and deformed mitochondria. In ASM cells, TAS2R agonists decreased mitochondrial membrane potential and increased mitochondrial ROS and mitochondrial fragmentation. Inhibiting dynamin-like protein 1 (DLP1) reversed TAS2R agonist-induced mitochondrial membrane potential change and attenuated mitochondrial fragmentation and cell death. Furthermore, the expression of mitochondrial protein BCL2/adenovirus E1B 19-kDa protein-interacting protein 3 (Bnip3) and mitochondrial localization of DLP1 were significantly upregulated by TAS2R agonists. More importantly, inhibiting Bnip3 mitochondrial localization by dominant-negative Bnip3 significantly attenuated cell death induced by TAS2R agonist. Collectively the TAS2R agonists chloroquine and quinine modulate mitochondrial structure and function, resulting in ASM cell death. Furthermore, Bnip3 plays a central role in TAS2R agonist-induced ASM functional changes via a mitochondrial pathway. These findings further establish the cellular mechanisms of antimitogenic effects of TAS2R agonists and identify a novel class of receptors and pathways that can be targeted to mitigate airway remodeling as well as bronchoconstriction in obstructive airway diseases. Copyright © 2017 the American Physiological

  2. Osimertinib induces autophagy and apoptosis via reactive oxygen species generation in non-small cell lung cancer cells

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    Tang, Zheng-Hai; Cao, Wen-Xiang; Su, Min-Xia; Chen, Xiuping; Lu, Jin-Jian

    2017-01-01

    Osimertinib (OSI), also known as AZD9291, is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has been approved for the treatment of non-small cell lung cancer (NSCLC) patients harboring EGFR T790M mutation. Herein, we indicated for the first time that OSI increased the accumulations of cytoplasmic vacuoles, the expression of phosphatidylethanolamine-modified microtubule-associated protein light-chain 3 (LC3-II), and the formation of GFP-LC3 puncta in various cancer cells. The OSI-induced expression of LC3-II was further increased when combined treatment with chloroquine (CQ), an autophagy inhibitor, and the mRFP-EGFP-LC3 plasmid-transfected cells exposed to OSI led to the production of more red-fluorescent puncta than green-fluorescent puncta, indicating OSI induced autophagic flux in the NSCLC cells. Knockdown of EGFR showed no effect on the OSI-induced expression of LC3-II in NCI-H1975 cells. In addition, OSI increased reactive oxygen species (ROS) generation and scavenge of ROS via pretreatment with N-acetyl-L-cysteine (NAC), catalase (CAT), or vitamin E (Vita E) significantly inhibited OSI-induced the accumulations of cytoplasmic vacuoles, the expression of LC3-II, as well as the formation of GFP-LC3 puncta. Combinative treatment with CQ could not remarkably change the OSI-induced cell viability decrease, whereas the OSI-induced cell viability decrease and apoptosis could be reversed through pretreatment with NAC, CAT, and Vita E, respectively. Taken together, this is the first report that OSI induces an accompanied autophagy and the generation of ROS is critical for the OSI-induced autophagy, cell viability decrease, and apoptosis in NSCLC cells. - Highlights: • Osimertinib induced the expressions of cytoplasmic vacuoles and autophagic markers in different cancer cells. • Osimertinib induced autophagic flux in NSCLC NCI-H1975 and HCC827 cell lines. • ROS generation contributed to osimertinib-induced cytoplasmic

  3. Atorvastatin Protects Vascular Smooth Muscle Cells From TGF-β1-Stimulated Calcification by Inducing Autophagy via Suppression of the β-Catenin Pathway

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    Demin Liu

    2014-01-01

    Full Text Available Background: Arterial calcification is a major event in the progression of atherosclerosis. It is reported that statins exhibit various protective effects against vascular smooth muscle cell (VSMC inflammation and proliferation in cardiovascular remodeling. Although statins counteract atherosclerosis, the molecular mechanisms of statins on the calcium release from VSMCs have not been clearly elucidated. Methods: Calcium content of VSMCs was measured using enzyme-linked immunosorbent assay (ELISA. The expression of proteins involved in cellular transdifferentiation was analyzed by western blot. Cell autophagy was measured by fluorescence microscopic analysis for acridine orange staining and transmission electron microscopy analysis. The autophagic inhibitors (3-MA, chloroquine, NH4Cl and bafilomycin A1 and β-catenin inhibitor JW74 were used to assess the effects of atorvastatin on autophagy and the involvement of β-catenin on cell calcification respectively. Furthermore, cell transfection was performed to overexpress β-catenin. Results: In VSMCs, atorvastatin significantly suppressed transforming growth factor-β1 (TGF-β1-stimulated calcification, accompanied by the induction of autophagy. Downregulation of autophagy with autophagic inhibitors significantly suppressed the inhibitory effect of atorvastatin on cell calcification. Moreover, the beneficial effect of atorvastatin on calcification and autophagy was reversed by β-catenin overexpression. Conversely, JW74 supplement enhanced this effect. Conclusion: These data demonstrated that atorvastatin protect VSMC from TGF-β1-stimulated calcification by inducing autophagy through suppression of the β-catenin pathway, identifying autophagy induction might be a therapeutic strategy for use in vascular calcification.

  4. Large intergenic non-coding RNA-ROR reverses gemcitabine-induced autophagy and apoptosis in breast cancer cells.

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    Chen, Yao-Min; Liu, Yu; Wei, Hai-Yan; Lv, Ke-Zhen; Fu, Pei-Fen

    2016-09-13

    The purpose of this study was to elucidate the potential role of long intergenic non-protein coding RNA, regulator of reprogramming (linc-ROR) in gemcitabine (Gem)-induced autophagy and apoptosis in breast cancer cells. MDA-MB-231 cells were treated with short hairpin RNA (shRNA) to knockdown Linc-ROR expression in the presence of Gem. Gem treatment alone decreased cell survival and increased both apoptosis and autophagy. Gem treatment also increased the expression of LC3-II, Beclin 1, NOTCH1 and Bcl-2, but decreased expression of p62 and p53. Untreated MDA-MB-231 cell lines strongly expressed linc-ROR, but linc-ROR knockdown decreased cell viability and expression of p62 and p53 while increasing apoptosis. Linc-ROR knockdown also increased LC3-II/β-actin, Beclin 1, NOTCH1, and Bcl-2 expression, as well as the number of autophagic vesicles in MDA-MB-231 cells. Linc-ROR negatively regulated miR-34a expression by inhibiting histone H3 acetylation in the miR-34a promoter. We conclude that linc-ROR suppresses Gem-induced autophagy and apoptosis in breast cancer cells by silencing miR-34a expression.

  5. Tryptamine induces cell death with ultrastructural features of autophagy in neurons and glia: Possible relevance for neurodegenerative disorders.

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    Herrera, Federico; Martin, Vanesa; Carrera, Pilar; García-Santos, Guillermo; Rodriguez-Blanco, Jezabel; Rodriguez, Carmen; Antolín, Isaac

    2006-09-01

    Tryptamine derivatives are a family of biogenic amines that have been suggested to be modulators of brain function at physiological concentrations. However, pharmacological concentrations of these amines display amphetamine-like properties, and they seem to play a role in brain disorders. Amphetamines induce autophagy in nerve cells, and this type of cell death has also been involved in neurodegenerative diseases. In the present work, we clearly demonstrate for the very first time that high concentrations of tryptamine (0.1-1 mM) induce autophagy in HT22 and SK-N-SH nerve cell lines and in primary cultures of astrocytes, glial cells being less sensitive than neurons. Ultrastructural cell morphology shows all of the typical hallmarks of autophagy. There is no nuclear chromatin condensation, endoplasmic reticulum and mitochondria are swollen, and a great number of double-membraned autophagosomes and residual bodies can be shown in the cytoplasm. Autophagosomes and residual bodies contain mitochondria, membranes, and vesicles and remain unabridged until the cell membrane is disrupted and the cell dies. The same results have been found when cells were incubated with high concentrations of 5-methoxytryptamine (0.1-1 mM). Our results establish a possible link between the role of tryptamine derivatives in brain disorders and the presence of autophagic cell death in these kinds of disorders. (c) 2006 Wiley-Liss, Inc.

  6. Essential role of autophagy in fucoxanthin-induced cytotoxicity to human epithelial cervical cancer HeLa cells.

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    Hou, Li-li; Gao, Chao; Chen, Liang; Hu, Guo-qiang; Xie, Song-qiang

    2013-11-01

    To investigate the effects and the molecular mechanisms of fucoxanthin, a major carotenoid found in edible seaweed, on HeLa cells. The cytotoxicity of fucoxanthin was evaluated using MTT assay. Cell cycle and apoptosis were evaluated using flow cytometric analysis. Autophagy was detected with acridine orange staining and transient transfection of the GFP-LC3 plasmid into the cells. Protein expression was detected with Western blotting. Treatment of HeLa cells with fucoxanthin (10-80 μmol/L) for 48 h caused dose-dependent cytotoxicity with an IC50 value of 55.1±7.6 μmol/L. Fucoxanthin (10, 20, and 40 μmol/L) dose-dependently induced G0/G1 arrest, but did not change the apoptosis of HeLa cells. The same concentrations of fucoxanthin dose-dependently increased the protein expression of LC3 II (the autophagosome marker) and Beclin 1 (the initiation factor for autophagosome formation) in HeLa cells. Moreover, fucoxanthin dose-dependently decreased the levels of phosphorylated Akt and its downstream proteins p53, p70S6K, and mTOR, and increases the expression of PTEN in HeLa cells. Pretreatment of HeLa cells with 3-methyladenine (5 mmol/L) blocked the cytotoxic effect of fucoxanthin as well as fucoxanthin-induced autophagy. Fucoxanthin exerts autophagy-dependent cytotoxic effect in HeLa cells via inhibition of Akt/mTOR signaling pathway.

  7. Nitro/Nitrosyl-Ruthenium Complexes Are Potent and Selective Anti-Trypanosoma cruzi Agents Causing Autophagy and Necrotic Parasite Death

    Science.gov (United States)

    Bastos, Tanira M.; Barbosa, Marília I. F.; da Silva, Monize M.; da C. Júnior, José W.; Meira, Cássio S.; Guimaraes, Elisalva T.; Ellena, Javier; Moreira, Diogo R. M.; Batista, Alzir A.

    2014-01-01

    cis-[RuCl(NO2)(dppb)(5,5′-mebipy)] (complex 1), cis-[Ru(NO2)2(dppb)(5,5′-mebipy)] (complex 2), ct-[RuCl(NO)(dppb)(5,5′-mebipy)](PF6)2 (complex 3), and cc-[RuCl(NO)(dppb)(5,5′-mebipy)](PF6)2 (complex 4), where 5,5′-mebipy is 5,5′-dimethyl-2,2′-bipyridine and dppb is 1,4-bis(diphenylphosphino)butane, were synthesized and characterized. The structure of complex 2 was determined by X-ray crystallography. These complexes exhibited a higher anti-Trypanosoma cruzi activity than benznidazole, the current antiparasitic drug. Complex 3 was the most potent, displaying a 50% effective concentration (EC50) of 2.1 ± 0.6 μM against trypomastigotes and a 50% inhibitory concentration (IC50) of 1.3 ± 0.2 μM against amastigotes, while it displayed a 50% cytotoxic concentration (CC50) of 51.4 ± 0.2 μM in macrophages. It was observed that the nitrosyl complex 3, but not its analog lacking the nitrosyl group, releases nitric oxide into parasite cells. This release has a diminished effect on the trypanosomal protease cruzain but induces substantial parasite autophagy, which is followed by a series of irreversible morphological impairments to the parasites and finally results in cell death by necrosis. In infected mice, orally administered complex 3 (five times at a dose of 75 μmol/kg of body weight) reduced blood parasitemia and increased the survival rate of the mice. Combination index analysis of complex 3 indicated that its in vitro activity against trypomastigotes is synergic with benznidazole. In addition, drug combination enhanced efficacy in infected mice, suggesting that ruthenium-nitrosyl complexes are potential constituents for drug combinations. PMID:25092707

  8. A REDD1/TXNIP pro-oxidant complex regulates ATG4B activity to control stress-induced autophagy and sustain exercise capacity.

    Science.gov (United States)

    Qiao, Shuxi; Dennis, Michael; Song, Xiufeng; Vadysirisack, Douangsone D; Salunke, Devika; Nash, Zachary; Yang, Zhifen; Liesa, Marc; Yoshioka, Jun; Matsuzawa, Shu-Ichi; Shirihai, Orian S; Lee, Richard T; Reed, John C; Ellisen, Leif W

    2015-04-28

    Macroautophagy (autophagy) is a critical cellular stress response; however, the signal transduction pathways controlling autophagy induction in response to stress are poorly understood. Here we reveal a new mechanism of autophagy control whose deregulation disrupts mitochondrial integrity and energy homeostasis in vivo. Stress conditions including hypoxia and exercise induce reactive oxygen species (ROS) through upregulation of a protein complex involving REDD1, an mTORC1 inhibitor and the pro-oxidant protein TXNIP. Decreased ROS in cells and tissues lacking either REDD1 or TXNIP increases catalytic activity of the redox-sensitive ATG4B cysteine endopeptidase, leading to enhanced LC3B delipidation and failed autophagy. Conversely, REDD1/TXNIP complex expression is sufficient to induce ROS, suppress ATG4B activity and activate autophagy. In Redd1(-/-) mice, deregulated ATG4B activity and disabled autophagic flux cause accumulation of defective mitochondria, leading to impaired oxidative phosphorylation, muscle ATP depletion and poor exercise capacity. Thus, ROS regulation through REDD1/TXNIP is physiological rheostat controlling stress-induced autophagy.

  9. Autophagy participates in isoliquiritigenin-induced melanin degradation in human epidermal keratinocytes through PI3K/AKT/mTOR signaling.

    Science.gov (United States)

    Yang, Zhibo; Zeng, Biyun; Pan, Yi; Huang, Pan; Wang, Chang

    2018-01-01

    Melanin is the pigment responsible for the color of human skin and hair. Melanin serves as a double-edge sword which can exert both protective and spot-causing effects on skin. Although melanin has an important role in protecting the skin against UV damage, an excessive or uneven melanin production can lead to the formation of freckles and age spots. Isoliquiritigenin (ISL) has been reported to inhibit melanin synthesis; however, its role in melanin degradation remains unclear. In the present study, we evaluated the detailed function of ISL in melanin degradation in human epidermal keratinocytes. Since autophagy has been reported to be related to melanin degradation, we also examined the activation of autophagy by ISL treatment in keratinocytes by measurement of autophagy-related proteins, ATG7, LC3 and p62. Moreover, si-ATG7-induced ATG7 knockdown and autophagy inhibitor 3-MA decreased LC3 II protein levels and increased PMEL17, p62 and melanin levels in HaCaT cells, which could be partially reversed by ISL treatment, indicating that autophagy participated in melanin degradation. The decreased p-AKT and p-mTOR proteins upon ISL treatment indicated the involvement of PI3K/AKT/mTOR signaling in ISL-induced melanin degradation. Taken together, we demonstrated that autophagy participates in ISL-induced melanin degradation in human epidermal keratinocytes through PI3K/AKT/mTOR signaling. Copyright © 2017. Published by Elsevier Masson SAS.

  10. Autophagy in idiopathic pulmonary fibrosis.

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    Avignat S Patel

    Full Text Available Autophagy is a basic cellular homeostatic process important to cell fate decisions under conditions of stress. Dysregulation of autophagy impacts numerous human diseases including cancer and chronic obstructive lung disease. This study investigates the role of autophagy in idiopathic pulmonary fibrosis.Human lung tissues from patients with IPF were analyzed for autophagy markers and modulating proteins using western blotting, confocal microscopy and transmission electron microscopy. To study the effects of TGF-β(1 on autophagy, human lung fibroblasts were monitored by fluorescence microscopy and western blotting. In vivo experiments were done using the bleomycin-induced fibrosis mouse model.Lung tissues from IPF patients demonstrate evidence of decreased autophagic activity as assessed by LC3, p62 protein expression and immunofluorescence, and numbers of autophagosomes. TGF-β(1 inhibits autophagy in fibroblasts in vitro at least in part via activation of mTORC1; expression of TIGAR is also increased in response to TGF-β(1. In the bleomycin model of pulmonary fibrosis, rapamycin treatment is antifibrotic, and rapamycin also decreases expression of á-smooth muscle actin and fibronectin by fibroblasts in vitro. Inhibition of key regulators of autophagy, LC3 and beclin-1, leads to the opposite effect on fibroblast expression of á-smooth muscle actin and fibronectin.Autophagy is not induced in pulmonary fibrosis despite activation of pathways known to promote autophagy. Impairment of autophagy by TGF-β(1 may represent a mechanism for the promotion of fibrogenesis in IPF.

  11. Organometallic Gold(III) Complexes Similar to Tetrahydroisoquinoline Induce ER-Stress-Mediated Apoptosis and Pro-Death Autophagy in A549 Cancer Cells.

    Science.gov (United States)

    Huang, Ke-Bin; Wang, Feng-Yang; Tang, Xiao-Ming; Feng, Hai-Wen; Chen, Zhen-Feng; Liu, Yan-Cheng; Liu, You-Nian; Liang, Hong

    2018-04-26

    Agents inducing both apoptosis and autophagic death can be effective chemotherapeutic drugs. In our present work, we synthesized two organometallic gold(III) complexes harboring C^N ligands that structurally resemble tetrahydroisoquinoline (THIQ): Cyc-Au-1 (AuL 1 Cl 2 , L 1 = 3,4-dimethoxyphenethylamine) and Cyc-Au-2 (AuL 2 Cl 2 , L 2 = methylenedioxyphenethylamine). In screening their in vitro activity, we found both gold complexes exhibited lower toxicity, lower resistance factors, and better anticancer activity than those of cisplatin. The organometallic gold(III) complexes accumulate in mitochondria and induce elevated ROS and an ER stress response through mitochondrial dysfunction. These effects ultimately result in simultaneous apoptosis and autophagy. Importantly, compared to cisplatin, Cyc-Au-2 exhibits lower toxicity and better anticancer activity in a murine tumor model. To the best of our knowledge, Cyc-Au-2 is the first organometallic Au(III) compound that induces apoptosis and autophagic death. On the basis of our results, we believe Cyc-Au-2 to be a promising anticancer agent or lead compound for further anticancer drug development.

  12. Light-emitting diode 585nm photomodulation inhibiting melanin synthesis and inducing autophagy in human melanocytes.

    Science.gov (United States)

    Chen, Li; Xu, Zhongyi; Jiang, Min; Zhang, Chengfeng; Wang, Xuan; Xiang, Leihong

    2018-01-01

    Melasma is a common hyperpigmentation skin disease on face. Light-emitting diode (LED) photomodulation (585nm) is reported to be effective for the treatment of melasma. However, whether and how LED photomodulation would influence melanogenesis of human epidermal melanocytes (HEMs) is unknown. To evaluate the effects of LED photomodulation (585nm) on melanogenesis in HEMs. HEMs were irradiated with fluences of 0, 5, 10 and 20J/cm 2 585nm LED light. After 5-day treatment, cell viability was analyzed by CCK-8 assay, and apoptosis was assessed by Annexin V APC assay. Melanin content and tyrosinase activity were measured by spectrophotometer. Melanosome stage and autophagosomes were determined under transmission electron microscope (TEM). The formation of autophagic punctate structures was observed under confocal microscope. RT-PCR and western blotting were used to assess the expression of relative mRNA and protein levels. Yellow light LED 585nm had no effects on HEMs cell viability and apoptosis. Treatment with LED 585nm from 5J/cm 2 to 20J/cm 2 inhibited melanosome maturation, decreased melanin content and tyrosinase activity. Inhibition was accompanied by the decreased expression of tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1) and microphthalmia-associated transcription factor (MITF) on both mRNA and protein levels. Autophagosomes were observed under TEM. Autophagic punctate structures of microtubule-associated protein light chain 3 (LC3) proteins were induced by LED 585nm light. The configuration change of LC3 from LC3-I to LC3-II, and the degradation of p62 protein were observed after LED 585nm. Furthermore, we also revealed that the anti-melanogenic effect of LED 585nm photomodulation was reversed by 3-Methyladenine (3-MA), which inhibits autophagy by blocking autophagosome formation via the inhibition of type III Phosphatidylinositol 3-kinases (PI-3K). Our finding demonstrated that LED photomodulation with 585nm wavelength suppressed melanin content in

  13. Bag3-induced autophagy is associated with degradation of JCV oncoprotein, T-Ag.

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    Ilker Kudret Sariyer

    Full Text Available JC virus, JCV, is a human neurotropic polyomavirus whose replication in glial cells causes the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML. In addition, JCV possesses oncogenic activity and expression of its transforming protein, large T-antigen (T-Ag, in several experimental animals induces tumors of neural origin. Further, the presence of JCV DNA and T-Ag have been repeatedly observed in several human malignant tissues including primitive neuroectodermal tumors and glioblastomas. Earlier studies have demonstrated that Bag3, a member of the Bcl-2-associated athanogene (Bag family of proteins, which is implicated in autophagy and apoptosis, is downregulated upon JCV infection of glial cells and that JCV T-Ag is responsible for suppressing the activity of the BAG3 promoter. Here, we investigated the possible impact of Bag3 on T-Ag expression in JCV-infected human primary glial cells as well as in cells derived from T-Ag-induced medulloblastoma in transgenic animals. Results from these studies revealed that overexpression of Bag3 drastically decreases the level of T-Ag expression by inducing the autophagic degradation of the viral protein. Interestingly, this event leads to the inhibition of JCV infection of glial cells, suggesting that the reduced levels of T-antigen seen upon the overexpression of Bag3 has a biological impact on the viral lytic cycle. Results from protein-protein interaction studies showed that T-Ag and Bag3 physically interact with each other through the zinc-finger of T-Ag and the proline rich domains of Bag3, and this interaction is important for the autophagic degradation of T-Ag. Our observations open a new avenue of research for better understanding of virus-host interaction by investigating the interplay between T-Ag and Bag3, and their impact on the development of JCV-associated diseases.

  14. MicroRNA profiling in human colon cancer cells during 5-fluorouracil-induced autophagy.

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    Ni Hou

    Full Text Available Autophagy modulation is now recognized as a potential therapeutic approach for cancer (including colorectal cancer, yet the molecular mechanisms regulating autophagy in response to cellular stress are still not well understood. MicroRNAs (miRNAs have been found to play important roles in controlling many cellular functions, including growth, metabolism and stress response. The physiological importance of the miRNA-autophagy interconnection is only beginning to be elucidated. MiRNA microarray technology facilitates analysis of global miRNA expression in certain situations. In this study, we explored the expression profile of miRNAs during the response of human colon cancer cells (HT29s to 5-FU treatment and nutrient starvation using miRNA microarray analysis. The alteration of miRNA expression showed the same pattern under both conditions was further testified by qRT-PCR in three human colon cancer cell lines. In addition, bioinformatic prediction of target genes, pathway analysis and gene network analysis were performed to better understand the roles of these miRNAs in the regulation of autophagy. We identified and selected four downregulated miRNAs including hsa-miR-302a-3p and 27 upregulated miRNAs under these two conditions as having the potential to target genes involved in the regulation of autophagy in human colon cancer cells. They have the potential to modulate autophagy in 5-FU-based chemotherapy in colorectal cancer.

  15. Subversion of autophagy in adherent invasive Escherichia coli-infected neutrophils induces inflammation and cell death.

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    Abderrahman Chargui

    Full Text Available Invading bacteria are recognized, captured and killed by a specialized form of autophagy, called xenophagy. Recently, defects in xenophagy in Crohn's disease (CD have been implicated in the pathogenesis of human chronic inflammatory diseases of uncertain etiology of the gastrointestinal tract. We show here that pathogenic adherent-invasive Escherichia coli (AIEC isolated from CD patients are able to adhere and invade neutrophils, which represent the first line of defense against bacteria. Of particular interest, AIEC infection of neutrophil-like PLB-985 cells blocked autophagy at the autolysosomal step, which allowed intracellular survival of bacteria and exacerbated interleukin-8 (IL-8 production. Interestingly, this block in autophagy correlated with the induction of autophagic cell death. Likewise, stimulation of autophagy by nutrient starvation or rapamycin treatment reduced intracellular AIEC survival and IL-8 production. Finally, treatment with an inhibitor of autophagy decreased cell death of AIEC-infected neutrophil-like PLB-985 cells. In conclusion, excessive autophagy in AIEC infection triggered cell death of neutrophils.

  16. The Beta Adrenergic Receptor Blocker Propranolol Counteracts Retinal Dysfunction in a Mouse Model of Oxygen Induced Retinopathy: Restoring the Balance between Apoptosis and Autophagy

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    Maurizio Cammalleri

    2017-12-01

    Full Text Available In a mouse model of oxygen induced retinopathy (OIR, beta adrenergic receptor (BAR blockade has been shown to recover hypoxia-associated retinal damages. Although the adrenergic signaling is an important regulator of apoptotic and autophagic processes, the role of BARs in retinal cell death remains to be elucidated. The present study was aimed at investigating whether ameliorative effects of BAR blockers may occur through their coordinated action on apoptosis and autophagy. To this aim, retinas from control and OIR mice untreated or treated with propranolol, a non-selective BAR1/2 blocker, were characterized in terms of expression and localization of apoptosis and autophagy markers. The effects of propranolol on autophagy signaling were also evaluated and specific autophagy modulators were used to get functional information on the autophagic effects of BAR antagonism. Finally, propranolol effects on neurodegenerative processes were associated to an electrophysiological investigation of retinal function by recording electroretinogram (ERG. We found that retinas of OIR mice are characterized by increased apoptosis and decreased autophagy, while propranolol reduces apoptosis and stimulates autophagy. In particular, propranolol triggers autophagosome formation in bipolar, amacrine and ganglion cells that are committed to die by apoptosis in response to hypoxia. Also our data argue that propranolol, through the inhibition of the Akt-mammalian target of rapamycin pathway, activates autophagy which decreases retinal cell death. At the functional level, propranolol recovers dysfunctional ERG by recovering the amplitude of a- and b-waves, and oscillatory potentials, thus indicating an efficient restoring of retinal transduction. Overall, our results demonstrate that BAR1/2 are key regulators of retinal apoptosis/autophagy, and that BAR1/2 blockade leads to autophagy-mediated neuroprotection. Reinstating the balance between apoptotic and autophagic

  17. The pan-inhibitor of Aurora kinases danusertib induces apoptosis and autophagy and suppresses epithelial-to-mesenchymal transition in human breast cancer cells

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    Li, Jin-Ping; Yang, Yin-Xue; Liu, Qi-Lun; Zhou, Zhi-Wei; Pan, Shu-Ting; He, Zhi-Xu; Zhang, Xueji; Yang, Tianxin; Pan, Si-Yuan; Duan, Wei; He, Shu-Ming; Chen, Xiao-Wu; Qiu, Jia-Xuan; Zhou, Shu-Feng

    2015-01-01

    Danusertib (Danu) is a pan-inhibitor of Aurora kinases and a third-generation breakpoint cluster region-Abelson murine leukemia viral oncogene homolog 1 (Bcr-Abl) tyrosine kinase inhibitor, but its antitumor effect and underlying mechanisms in the treatment of human breast cancer remain elusive. This study aimed to investigate the effects of Danu on the growth, apoptosis, autophagy, and epithelial-to-mesenchymal transition (EMT) and the molecular mechanisms in human breast cancer MCF7 and MDA-MB-231 cells. The results demonstrated that Danu remarkably inhibited cell proliferation, induced apoptosis and autophagy, and suppressed EMT in both breast cancer cell lines. Danu arrested MCF7 and MDA-MB-231 cells in G2/M phase, accompanied by the downregulation of cyclin-dependent kinase 1 and cyclin B1 and upregulation of p21 Waf1/Cip1, p27 Kip1, and p53. Danu significantly decreased the expression of B-cell lymphoma-extra-large (Bcl-xl) and B-cell lymphoma 2 (Bcl-2), but increased the expression of Bcl-2-associated X protein (Bax) and p53-upregulated modulator of apoptosis (PUMA), and promoted the cleavage of caspases 3 and 9. Furthermore, Danu significantly increased the expression levels of the membrane-bound microtubule-associated protein 1A/1B-light chain 3 (LC3-II) and beclin 1 in breast cancer cells, two markers for autophagy. Danu induced the activation of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinases 1 and 2 (Erk1/2) and inhibited the activation of protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathways in breast cancer cells. Treatment with wortmannin (a phosphatidylinositol 3-kinase inhibitor) markedly inhibited Danu-induced activation of p38 MAPK and conversion of cytosolic LC3-I to membrane-bound LC3-II. Pharmacological inhibition and small interfering RNA-mediated knockdown of p38 MAPK suppressed Akt activation, resulting in LC3-II accumulation and enhanced autophagy. Pharmacological inhibition

  18. Schwann cell autophagy induced by SAHA, 17-AAG, or clonazepam can reduce bortezomib-induced peripheral neuropathy

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    Watanabe, T; Nagase, K; Chosa, M; Tobinai, K

    2010-01-01

    Background: The proteasome inhibitor bortezomib has improved the survival of patients with multiple myeloma but bortezomib-induced peripheral neuropathy (BiPN) has emerged as a serious potential complication of this therapy. Animal studies suggest that bortezomib predominantly causes pathological changes in Schwann cells. A tractable system to evaluate combination drugs for use with bortezomib is essential to enable continuing clinical benefit from this drug. Methods: Rat schwannoma cells were pretreated with vincristine (VCR), histone deacetylase inhibitors, anticonvulsants, or a heat-shock protein 90 (HSP90) inhibitor. To then monitor aggresome formation as a result of proteasome inhibition and the activation of chaperone-mediated autophagy (CMA), we performed double-labelling immunofluorescent analyses of a cellular aggregation-prone protein marker. Results: Aggresome formation was interrupted by VCR, whereas combination treatments with bortezomib involving suberoylanilide hydroxamic acid, 17-allylamino-17-demethoxy-geldanamycin, or clonazepam appear to facilitate the disposal of unfolded proteins via CMA, inducing HSP70 and lysosome-associated membrane protein type 2A (LAMP-2A). Conclusions: This schwannoma model can be used to test BiPN-reducing drugs. The present data suggest that aggresome formation in Schwann cells is a possible mechanism of BiPN, and drugs that induce HSP70 or LAMP-2A have the potential to alleviate this complication. Combination clinical trials are warranted to confirm the relevance of these observations. PMID:20959823

  19. Overcoming resistance to mitochondrial apoptosis by BZML-induced mitotic catastrophe is enhanced by inhibition of autophagy in A549/Taxol cells.

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    Bai, Zhaoshi; Gao, Meiqi; Xu, Xiaobo; Zhang, Huijuan; Xu, Jingwen; Guan, Qi; Wang, Qing; Du, Jianan; Li, Zhengqiang; Zuo, Daiying; Zhang, Weige; Wu, Yingliang

    2018-03-01

    Our previous in vitro study showed that 5-(3, 4, 5-trimethoxybenzoyl)-4-methyl-2-(p-tolyl) imidazol (BZML) is a novel colchicine binding site inhibitor with potent anti-cancer activity against apoptosis resistance in A549/Taxol cells through mitotic catastrophe (MC). However, the mechanisms underlying apoptosis resistance in A549/Taxol cells remain unknown. To clarify these mechanisms, in the present study, we investigated the molecular mechanisms of apoptosis and autophagy, which are closely associated with MC in BZML-treated A549 and A549/Taxol cells. Xenograft NSCLC models induced by A549 and A549/Taxol cells were used to evaluate the efficacy of BZML in vivo. The activation of the mitochondrial apoptotic pathway was assessed using JC-1 staining, Annexin V-FITC/PI double-staining, a caspase-9 fluorescence metric assay kit and western blot. The different functional forms of autophagy were distinguished by determining the impact of autophagy inhibition on drug sensitivity. Our data showed that BZML also exhibited desirable anti-cancer activity against drug-resistant NSCLC in vivo. Moreover, BZML caused ROS generation and MMP loss followed by the release of cytochrome c from mitochondria to cytosol in both A549 and A549/Taxol cells. However, the ROS-mediated apoptotic pathway involving the mitochondria that is induced by BZML was only fully activated in A549 cells but not in A549/Taxol cells. Importantly, we found that autophagy acted as a non-protective type of autophagy during BZML-induced apoptosis in A549 cells, whereas it acted as a type of cytoprotective autophagy against BZML-induced MC in A549/Taxol cells. Our data suggest that the anti-apoptosis property of A549/Taxol cells originates from a defect in activation of the mitochondrial apoptotic pathway, and autophagy inhibitors can potentiate BZML-induced MC to overcome resistance to mitochondrial apoptosis. © 2018 John Wiley & Sons Ltd.

  20. Inhibition of acrolein-induced autophagy and apoptosis by a glycosaminoglycan from Sepia esculenta ink in mouse Leydig cells.

    Science.gov (United States)

    Gu, Yi-Peng; Yang, Xiao-Mei; Luo, Ping; Li, Yan-Qun; Tao, Ye-Xing; Duan, Zhen-Hua; Xiao, Wei; Zhang, Da-Yan; Liu, Hua-Zhong

    2017-05-01

    In our recent reports, a squid ink polysaccharide (SIP) was found having preventive activity against cyclophosphamide induced damage in mouse testis and ovary. Here we further reveal the regulative mechanism of SIP against chemical toxicity on testis. Leydig cells exposed to acrolein (ACR) underwent apoptosis at 12h and 24h. Before apoptosis, cells occurred autophagy that was confirmed by high autophagic rate and Beclin-1 protein content at 3h. PI3K/Akt and p38 MAPK signal pathways involved in the regulatory mechanisms. These outcomes of ACR were recovered completely by SIP, which was demonstrated by attenuated disruption of redox equilibrium and increased testosterone production, through suppressing ACR-caused autophagy and apoptosis regulated by PI3K/Akt and p38 MAPK signal pathways in Leydig cells. Summarily, autophagy occurred before apoptosis caused by ACR-activated p38 MAPK and PI3K/Akt pathways were blocked by SIP, resulting in survival and functional maintenance of Leydig cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Chronic expression of Ski induces apoptosis and represses autophagy in cardiac myofibroblasts.

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    Zeglinski, Matthew R; Davies, Jared J L; Ghavami, Saeid; Rattan, Sunil G; Halayko, Andrew J; Dixon, Ian M C

    2016-06-01

    Inappropriate cardiac interstitial remodeling is mediated by activated phenoconverted myofibroblasts. The synthesis of matrix proteins by these cells is triggered by both chemical and mechanical stimuli. Ski is a repressor of TGFβ1/Smad signaling and has been described as possessing anti-fibrotic properties within the myocardium. We hypothesized that overexpression of Ski in myofibroblasts will induce an apoptotic response, which may either be supported or opposed by autophagic flux. We used primary myofibroblasts (activated fibroblasts) which were sourced from whole heart preparations that were only passaged once. We found that overexpression of Ski results in distinct morphological and biochemical changes within primary cardiac myofibroblasts associated with apoptosis. Ski treatment was associated with the expression of pro-apoptotic factors such as Bax, caspase-7, and -9. Our results indicate that Ski triggers a pro-death mechanism in primary rat cardiac myofibroblasts that is mediated through the intrinsic apoptotic pathway. Myofibroblast survival is prolonged by an autophagic response, as the dataset indicate that apoptosis is hastened when autophagy is inhibited. We suggest that the apoptotic death response of myofibroblasts is working in parallel with the previously observed anti-fibrotic properties of Ski within this cell type. As myofibroblasts are the sole mediators of matrix expansion in heart failure, we suggest that Ski, or a putative Ski-mimetic, may induce graded apoptosis in myofibroblasts within the failing heart and may be a novel therapeutic approach towards controlling cardiac fibrosis. Future studies are needed to examine the potential effects of Ski overexpression on other cell types in the heart. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. 17-AAG induces cytoplasmic alpha-synuclein aggregate clearance by induction of autophagy.

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    Riedel, Michael; Goldbaum, Olaf; Schwarz, Lisa; Schmitt, Sebastian; Richter-Landsberg, Christiane

    2010-01-18

    The accumulation and aggregation of alpha-synuclein in nerve cells and glia are characteristic features of a number of neurodegenerative diseases termed synucleinopathies. alpha-Synuclein is a highly soluble protein which in a nucleation dependent process is capable of self-aggregation. The causes underlying aggregate formation are not yet understood, impairment of the proteolytic degradation systems might be involved. In the present study the possible aggregate clearing effects of the geldanamycin analogue 17-AAG (17-(Allylamino)-17-demethoxygeldanamycin) was investigated. Towards this, an oligodendroglial cell line (OLN-93 cells), stably expressing human alpha-synuclein (A53T mutation) was used. In these cells small punctate aggregates, not staining with thioflavine S, representing prefibrillary aggregates, occur characteristically. Our data demonstrate that 17-AAG attenuated the formation of alpha-synuclein aggregates by stimulating macroautophagy. By blocking the lysosomal compartment with NH(4)Cl the aggregate clearing effects of 17-AAG were abolished and alpha-synuclein deposits were enlarged. Analysis of LC3-II immunoreactivity, which is an indicator of autophagosome formation, further revealed that 17-AAG led to the recruitment of LC3-II and to the formation of LC3 positive puncta. This effect was also observed in cultured oligodendrocytes derived from the brains of newborn rats. Inhibition of macroautophagy by 3-methyladenine prevented 17-AAG induced occurrence of LC3 positive puncta as well as the removal of alpha-synuclein aggregates in OLN-A53T cells. Our data demonstrate for the first time that 17-AAG not only causes the upregulation of heat shock proteins, but also is an effective inducer of the autophagic pathway by which alpha-synuclein can be removed. Hence geldanamycin derivatives may provide a means to modulate autophagy in neural cells, thereby ameliorating pathogenic aggregate formation and protecting the cells during disease and aging.

  3. Bardoxolone methyl induces apoptosis and autophagy and inhibits epithelial-to-mesenchymal transition and stemness in esophageal squamous cancer cells

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    Wang YY

    2015-02-01

    , cleaved caspase-9, and cleaved poly ADP ribose polymerase (PARP levels but increased the expression level of Bcl-2-associated X (Bax. Furthermore, CDDO-Me induced autophagy in both Ec109 and KYSE70 cells via suppression of the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR signaling pathway. There were interactions between the autophagic and apoptotic pathways in Ec109 and KYSE70 cells subject to CDDO-Me treatment. CDDO-Me also scavenged reactive oxygen species through activation of the nuclear factor (erythroid-derived 2-related factor 2 (Nrf2 pathway in Ec109 and KYSE70 cells. CDDO-Me inhibited cell invasion, epithelial–mesenchymal transition, and stemness in Ec109 and KYSE70 cells. CDDO-Me significantly downregulated E-cadherin but upregulated Snail, Slug, and zinc finger E-box-binding homeobox 1 (TCF-8/ZEB1 in Ec109 and KYSE70 cells. CDDO-Me significantly decreased the expression of octamer-4, sex determining region Y-box 2 (Sox-2, Nanog, and B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1, all markers of cancer cell stemness, in Ec109 and KYSE70 cells. Taken together, these results indicate that CDDO-Me is a promising anticancer agent against ESCC. Further studies are warranted to explore the molecular targets, efficacy and safety of CDDO-Me in the treatment of ESCC.Keywords: CDDO-Me, esophageal squamous cell carcinoma, cell cycle, apoptosis, autophagy, EMT, stemness, Akt, mTOR

  4. [Autophagy in the kidney].

    Science.gov (United States)

    Pallet, Nicolas

    2017-03-01

    Autophagy is a highly conserved, physiological, catabolic process, involving the lysosomal degradation of cytosolic components, including macromolecules (such as proteins and lipids) and cytosolic organelles. Autophagy is believed to be essential for the maintenance of cellular homeostasis, for a number of fundamental biological activities, and an important component of the complex response of cells to multiple forms of stress. Autophagy is involved in the pathogenesis of a number of clinically important disorders but, until recently, little was known about its connection to kidney diseases. However, there is now growing evidence that autophagy is specifically linked to the pathogenesis of important renal diseases such as acute kidney injury, diabetic nephropathy and polycystic kidney disease. However, an understanding of the precise role of autophagy in the course of kidney diseases is still in its infancy. The review points out areas of particular interest for future research, and also discusses the importance of such information on whether the pharmacologic agents that modulate autophagy are potentially usable as novel forms of treatment for various kidney diseases. © 2017 médecine/sciences – Inserm.

  5. DMH1 (4-[6-(4-isopropoxyphenylpyrazolo[1,5-a]pyrimidin-3-yl]quinoline inhibits chemotherapeutic drug-induced autophagy

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    Yue Sheng

    2015-07-01

    Full Text Available Our previous work found that DMH1 (4-[6-(4-isopropoxyphenylpyrazolo [1,5-a]pyrimidin-3-yl]quinoline was a novel autophagy inhibitor. Here, we aimed to investigate the effects of DMH1 on chemotherapeutic drug-induced autophagy as well as the efficacy of chemotherapeutic drugs in different cancer cells. We found that DMH1 inhibited tamoxifen- and cispcis-diaminedichloroplatinum (II (CDDP-induced autophagy responses in MCF-7 and HeLa cells, and potentiated the anti-tumor activity of tamoxifen and CDDP for both cells. DMH1 inhibited 5-fluorouracil (5-FU-induced autophagy responses in MCF-7 and HeLa cells, but did not affect the anti-tumor activity of 5-FU for these two cell lines. DMH1 itself did not induce cell death in MCF-7 and HeLa cells, but inhibited the proliferation of these cells. In conclusion, DMH1 inhibits chemotherapeutic drug-induced autophagy response and the enhancement of efficacy of chemotherapeutic drugs by DMH1 is dependent on the cell sensitivity to drugs.

  6. Adipocyte Fatty Acid Binding Protein Potentiates Toxic Lipids-Induced Endoplasmic Reticulum Stress in Macrophages via Inhibition of Janus Kinase 2-dependent Autophagy.

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    Hoo, Ruby L C; Shu, Lingling; Cheng, Kenneth K Y; Wu, Xiaoping; Liao, Boya; Wu, Donghai; Zhou, Zhiguang; Xu, Aimin

    2017-01-17

    Lipotoxicity is implicated in the pathogenesis of obesity-related inflammatory complications by promoting macrophage infiltration and activation. Endoplasmic reticulum (ER) stress and adipocyte fatty acid binding protein (A-FABP) play key roles in obesity and mediate inflammatory activity through similar signaling pathways. However, little is known about their interplay in lipid-induced inflammatory responses. Here, we showed that prolonged treatment of palmitic acid (PA) increased ER stress and expression of A-FABP, which was accompanied by reduced autophagic flux in macrophages. Over-expression of A-FABP impaired PA-induced autophagy associating with enhanced ER stress and pro-inflammatory cytokine production, while genetic ablation or pharmacological inhibition of A-FABP reversed the conditions. PA-induced expression of autophagy-related protein (Atg)7 was attenuated in A-FABP over-expressed macrophages, but was elevated in A-FABP-deficient macrophages. Mechanistically, A-FABP potentiated the effects of PA by inhibition of Janus Kinase (JAK)2 activity, thus diminished PA-induced Atg7 expression contributing to impaired autophagy and further augmentation of ER stress. These findings suggest that A-FABP acts as autophagy inhibitor to instigate toxic lipids-induced ER stress through inhibition of JAK2-dependent autophagy, which in turn triggers inflammatory responses in macrophages. A-FABP-JAK2 axis may represent an important pathological pathway contributing to obesity-related inflammatory diseases.

  7. Autophagy in Measles Virus Infection

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    Aurore Rozières

    2017-11-01

    Full Text Available Autophagy is a biological process that helps cells to recycle obsolete cellular components and which greatly contributes to maintaining cellular integrity in response to environmental stress factors. Autophagy is also among the first lines of cellular defense against invading microorganisms, including viruses. The autophagic destruction of invading pathogens, a process referred to as xenophagy, involves cytosolic autophagy receptors, such as p62/SQSTM1 (Sequestosome 1 or NDP52/CALCOCO2 (Nuclear Dot 52 KDa Protein/Calcium Binding And Coiled-Coil Domain 2, which bind to microbial components and target them towards growing autophagosomes for degradation. However, most, if not all, infectious viruses have evolved molecular tricks to escape from xenophagy. Many viruses even use autophagy, part of the autophagy pathway or some autophagy-associated proteins, to improve their infectious potential. In this regard, the measles virus, responsible for epidemic measles, has a unique interface with autophagy as the virus can induce multiple rounds of autophagy in the course of infection. These successive waves of autophagy result from distinct molecular pathways and seem associated with anti- and/or pro-measles virus consequences. In this review, we describe what the autophagy–measles virus interplay has taught us about both the biology of the virus and the mechanistic orchestration of autophagy.

  8. Dengue Virus and Autophagy

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    Nicholas S. Heaton

    2011-08-01

    Full Text Available Several independent groups have published that autophagy is required for optimal RNA replication of dengue virus (DENV. Initially, it was postulated that autophagosomes might play a structural role in replication complex formation. However, cryo-EM tomography of DENV replication complexes showed that DENV replicates on endoplasmic reticulum (ER cisternae invaginations and not on classical autophagosomes. Recently, it was reported that autophagy plays an indirect role in DENV replication by modulating cellular lipid metabolism. DENV-induced autophagosomes deplete cellular triglycerides that are stored in lipid droplets, leading to increased β-oxidation and energy production. This is the first example of a virus triggering autophagy to modulate cellular physiology. In this review, we summarize these data and discuss new questions and implications for autophagy during DENV replication.

  9. Starvation induced cell death in autophagy-defective yeast mutants is caused by mitochondria dysfunction.

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    Sho W Suzuki

    2011-02-01

    Full Text Available Autophagy is a highly-conserved cellular degradation and recycling system that is essential for cell survival during nutrient starvation. The loss of viability had been used as an initial screen to identify autophagy-defective (atg mutants of the yeast Saccharomyces cerevisiae, but the mechanism of cell death in these mutants has remained unclear. When cells grown in a rich medium were transferred to a synthetic nitrogen starvation media, secreted metabolites lowered the extracellular pH below 3.0 and autophagy-defective mutants mostly died. We found that buffering of the starvation medium dramatically restored the viability of atg mutants. In response to starvation, wild-type (WT cells were able to upregulate components of the respiratory pathway and ROS (reactive oxygen species scavenging enzymes, but atg mutants lacked this synthetic capacity. Consequently, autophagy-defective mutants accumulated the high level of ROS, leading to deficient respiratory function, resulting in the loss of mitochondria DNA (mtDNA. We also showed that mtDNA deficient cells are subject to cell death under low pH starvation conditions. Taken together, under starvation conditions non-selective autophagy, rather than mitophagy, plays an essential role in preventing ROS accumulation, and thus in maintaining mitochondria function. The failure of response to starvation is the major cause of cell death in atg mutants.

  10. Combined therapy with m-TOR-dependent and -independent autophagy inducers causes neurotoxicity in a mouse model of Machado-Joseph disease.

    Science.gov (United States)

    Duarte-Silva, S; Silva-Fernandes, A; Neves-Carvalho, A; Soares-Cunha, C; Teixeira-Castro, A; Maciel, P

    2016-01-28

    A major pathological hallmark in several neurodegenerative disorders, like polyglutamine disorders (polyQ), including Machado-Joseph disease (MJD), is the formation of protein aggregates. MJD is caused by a CAG repeat expansion in the ATXN3 gene, resulting in an abnormal protein, which is prone to misfolding and forms cytoplasmic and nuclear aggregates within neurons, ultimately inducing neurodegeneration. Treatment of proteinopathies with drugs that up-regulate autophagy has shown promising results in models of polyQ diseases. Temsirolimus (CCI-779) inhibits the mammalian target of rapamycin (m-TOR), while lithium chloride (LiCl) acts by inhibiting inositol monophosphatase, both being able to induce autophagy. We have previously shown that chronic treatment with LiCl (10.4 mg/kg) had limited effects in a transgenic MJD mouse model. Also, others have shown that CCI-779 had mild positive effects in a different mouse model of the disease. It has been suggested that the combination of mTOR-dependent and -independent autophagy inducers could be a more effective therapeutic approach. To further explore this avenue toward therapy, we treated CMVMJD135 transgenic mice with a conjugation of CCI-779 and LiCl, both at concentrations known to induce autophagy and not to be toxic. Surprisingly, this combined treatment proved to be deleterious to both wild-type (wt) and transgenic animals, failing to rescue their neurological symptoms and actually exerting neurotoxic effects. These results highlight the possible dangers of manipulating autophagy in the nervous system and suggest that a better understanding of the potential disruption in the autophagy pathway in MJD is required before successful long-term autophagy modulating therapies can be developed. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  11. Autophagy, Warburg, and Warburg Reverse Effects in Human Cancer

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    Claudio D. Gonzalez

    2014-01-01

    Full Text Available Autophagy is a highly regulated-cell pathway for degrading long-lived proteins as well as for clearing cytoplasmic organelles. Autophagy is a key contributor to cellular homeostasis and metabolism. Warburg hypothesized that cancer growth is frequently associated with a deviation of a set of energy generation mechanisms to a nonoxidative breakdown of glucose. This cellular phenomenon seems to rely on a respiratory impairment, linked to mitochondrial dysfunction. This mitochondrial dysfunction results in a switch to anaerobic glycolysis. It has been recently suggested that epithelial cancer cells may induce the Warburg effect in neighboring stromal fibroblasts in which autophagy was activated. These series of observations drove to the proposal of a putative reverse Warburg effect of pathophysiological relevance for, at least, some tumor phenotypes. In this review we introduce the autophagy process and its regulation and its selective pathways and role in cancer cell metabolism. We define and describe the Warburg effect and the newly suggested “reverse” hypothesis. We also discuss the potential value of modulating autophagy with several pharmacological agents able to modify the Warburg effect. The association of the Warburg effect in cancer and stromal cells to tumor-related autophagy may be of relevance for further development of experimental therapeutics as well as for cancer prevention.

  12. Targeting autophagy in cancer management – strategies and developments

    International Nuclear Information System (INIS)

    Ozpolat, Bulent; Benbrook, Doris M

    2015-01-01

    Autophagy is a highly regulated catabolic process involving lysosomal degradation of intracellular components, damaged organelles, misfolded proteins, and toxic aggregates, reducing oxidative stress and protecting cells from damage. The process is also induced in response to various conditions, including nutrient deprivation, metabolic stress, hypoxia, anticancer therapeutics, and radiation therapy to adapt cellular conditions for survival. Autophagy can function as a tumor suppressor mechanism in normal cells and dysregulation of this process (ie, monoallelic Beclin-1 deletion) may lead to malignant transformation and carcinogenesis. In tumors, autophagy is thought to promote tumor growth and progression by helping cells to adapt and survive in metabolically-challenged and harsh tumor microenvironments (ie, hypoxia and acidity). Recent in vitro and in vivo studies in preclinical models suggested that modulation of autophagy can be used as a therapeutic modality to enhance the efficacy of conventional therapies, including chemo and radiation therapy. Currently, more than 30 clinical trials are investigating the effects of autophagy inhibition in combination with cytotoxic chemotherapies and targeted agents in various cancers. In this review, we will discuss the role, molecular mechanism, and regulation of autophagy, while targeting this process as a novel therapeutic modality, in various cancers

  13. Molecular Switch Role of Akt in Polygonatum odoratum Lectin-Induced Apoptosis and Autophagy in Human Non-Small Cell Lung Cancer A549 Cells

    Science.gov (United States)

    Shi, Zheng; Wang, Hailian; Zhang, Bin; Zhao, Kailiang; Qi, Wei; Bao, Jinku; Wang, Yi

    2014-01-01

    Polygonatum odoratum lectin (POL), isolated from traditional Chinese medicine herb (Mill.) Druce, has drawn rising attention due to its wide biological activities. In the present study, anti-tumor effects, including apoptosis- and autophagy-inducing properties of POL, were determined by a series of cell biology methods such as MTT, cellular morphology observation, flow cytometry, immunoblotting. Herein, we found that POL could simultaneously induce apoptosis and autophagy in human non-small cell lung cancer A549 cells. POL initiated apoptosis through inhibiting Akt-NF-κB pathway, while POL triggered autophagy via suppressing Akt-mTOR pathway, suggesting the molecular switch role of Akt in regulating between POL-induced apoptosis and autophagy. Moreover, ROS was involved in POL-induced inhibition of Akt expression, and might therefore mediate both apoptosis and autophagy in A549 cells. In addition, POL displayed no significant cytotoxicity toward normal human embryonic lung fibroblast HELF cells. Due to the anti-tumor activities, POL might become a potent anti-cancer drug in future therapy, which might pave the way for exploring GNA-related lectins into effective drugs in cancer treatment. PMID:24992302

  14. Fentanyl induces autophagy via activation of the ROS/MAPK pathway and reduces the sensitivity of cisplatin in lung cancer cells.

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    Yao, Jiaqi; Ma, Chi; Gao, Wei; Liang, Jinxiao; Liu, Chang; Yang, Hongfang; Yan, Qiu; Wen, Qingping

    2016-12-01

    Cancer pain is the most common complication of lung carcinoma. Opioid agonist fentanyl is widely used for relieving pain in cancer patients, and cisplatin (DDP)‑based chemotherapy is commonly used for the treatment of advanced lung cancer; these two drugs are always used together in lung carcinoma patients. However, the mechanisms and related biological pathways by which fentanyl influences cisplatin sensitivity are relatively poorly reported. Here, we found that fentanyl reduces the sensitivity of cisplatin in human lung cancer cells and induces autophagy. Fentanyl induced reactive oxygen species (ROS) generation and JNK activation. N-acetyl‑L‑cysteine is a ROS scavenger and antioxidant, and the inhibition of JNK with SP600125 prevented fentanyl‑induced autophagy. We also found that 3-methyladenine (3-MA; an autophagy inhibitor) increased the sensitivity of DDP and weakened the inhibition of fentanyl. In conclusion, fentanyl reduces the sensitivity of cisplatin in lung cancer cells through the ROS-JNK-autophagy pathway, whereas the autophagy inhibitor 3-MA may weaken this effect.

  15. Role of hypoxia inducing factor-1β in alcohol-induced autophagy, steatosis and liver injury in mice.

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    Hong-Min Ni

    Full Text Available Chronic alcohol causes liver hypoxia and steatosis, which eventually develops into alcoholic liver disease (ALD. While it has been known that alcohol consumption activates hepatic hypoxia inducing factor-1α (HIF-1α, conflicting results regarding the role of HIF-1α in alcohol-induced liver injury and steatosis in mice have been reported. In the present study, we aimed to use hepatocyte-specific HIF-1β knockout mice to eliminate the possible compensatory effects of the single knockout of the 1α subunit of HIF to study the role of HIFs in ALD. C57BL/6 wild type mice were treated with acute ethanol to mimic human binge drinking. Matched wild-type and hepatocyte specific HIF-1β knockout mice were also subjected to a recently established Gao-binge alcohol model to mimic chronic plus binge conditions, which is quite common in human alcoholics. We found that acute alcohol treatment increased BNIP3 and BNIP3L/NIX expression in primary cultured hepatocytes and in mouse livers, suggesting that HIF may be activated in these models. We further found that hepatocyte-specific HIF-1β knockout mice developed less steatosis and liver injury following the Gao-binge model or acute ethanol treatment compared with their matched wild type mice. Mechanistically, protection against Gao-binge treatment-induced steatosis and liver injury was likely associated with increased FoxO3a activation and subsequent induction of autophagy in hepatocyte-specific HIF-1β knockout mice.

  16. Bone Marrow Mesenchymal Stem Cells Ameliorates Seawater-Exposure-Induced Acute Lung Injury by Inhibiting Autophagy in Lung Tissue

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    Qiu-ping Liu

    2014-01-01

    Full Text Available Seawater drowning can lead to acute lung injury (ALI. Several studies have shown that bone marrow mesenchymal stem cells (BMSC treatment could attenuate ALI. However, the mechanisms underlying this phenomenon still remain elusive. Therefore, this study aimed to investigate whether BMSC treatment can ameliorate seawater-induced ALI and its underlying mechanisms in a rat model. In this study, arterial blood gas, lung weight coefficient, and TNF-α, and IL-8 in bronchoalveolar lavage fluid (BALF, as well as histopathology examination, were used to detect the lung injury of seawater exposure. Moreover, western blot and RT-PCR were used to explore autophagy in lung tissues. The results demonstrated that seawater exposure induced ALI including impaired arterial blood gas, pulmonary edema, histopathologic changes, and inflammatory response in lung tissues. What is more, these changes were partly ameliorated by BMSC treatment through inhibition of autophagy in lung tissues. The application of BMSC may be a potential effective treatment for seawater-induced ALI.

  17. Autophagy induces apoptosis and death of T lymphocytes in the spleen of pigs infected with CSFV.

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    Gou, Hongchao; Zhao, Mingqiu; Fan, Shuangqi; Yuan, Jin; Liao, Jiedan; He, Wencheng; Xu, Hailuan; Chen, Jinding

    2017-10-19

    Lymphocyte depletion and immunosuppression are typical clinical characteristics of pigs infected with classical swine fever virus (CSFV). The apoptosis of virus-infected and bystander cells plays a role in the immunopathology of classical swine fever (CSF). Here, we offer the first evidence that autophagy is involved in apoptosis and death of T lymphocytes in the spleen of pigs infected with CSFV. Using immunohistochemical assays, we observed that more LC3II-positive cells appear in the T-cell zone of spleens. Spleen cell apoptosis was demonstrated using flow cytometry and TUNEL staining. Confocal immunofluorescence revealed that partial LC3II-positive cells were simultaneously TUNEL-positive. By cultivating spleen cells ex vivo, we demonstrated that the inhibition of autophagy by 3-MA treatment inhibited apoptosis and death of T lymphocytes caused by CSFV infection but did not have this effect  on B lymphocytes. Further observations demonstrated that uninfected cells in the spleen were also undergoing autophagy in vivo. In summary, these results linked autophagy with the apoptosis and cell death of splenic T cells, providing a new outlook to understand the mechanism of T lymphocyte depletion and immunosuppression during CSF.

  18. Immunomodulatory Protein from Ganoderma microsporum Induces Pro-Death Autophagy through Akt-mTOR-p70S6K Pathway Inhibition in Multidrug Resistant Lung Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Ling-Yen Chiu

    Full Text Available Chemoresistance in cancer therapy is an unfavorable prognostic factor in non-small cell lung cancer (NSCLC. Elevation of intracellular calcium level in multidrug resistant (MDR sublines leads to sensitization of MDR sublines to cell death. We demonstrated that a fungal protein from Ganoderma microsporum, GMI, elevates the intracellular calcium level and reduces the growth of MDR subline via autophagy and apoptosis, regardless of p-glycoprotein (P-gp overexpression, in mice xenograft tumors. In addition, we examined the roles of autophagy in the death of MDR A549 lung cancer sublines by GMI, thapsigargin (TG and tunicamycin (TM in vitro. Cytotoxicity of TG was inhibited by overexpressed P-gp. However, TM-induced death of MDR sublines was independent of P-gp level. Combinations of TG and TM with either docetaxel or vincristine showed no additional cytotoxic effects on MDR sublines. TG- and TM-mediated apoptosis of MDR sublines was demonstrated on Annexin-V assay and Western blot and repressed by pan-caspase inhibitor (Z-VAD-FMK. Treatment of MDR sublines with TG and TM also augmented autophagy with accumulation of LC3-II proteins, breakdown of p62 and formation of acidic vesicular organelles (AVOs. Inhibition of ATG5 by shRNA silencing significantly reduced autophagy and cell death but not apoptosis following TG or TM treatment. GMI treatment inhibited the phosphorylation of Akt/S473 and p70S6K/T389. Interestingly, the phosphorylation of ERK was not associated with GMI-induced autophagy. We conclude that autophagy plays a pro-death role in acquired MDR and upregulation of autophagy by GMI via Akt/mTOR inhibition provides a potential strategy for overcoming MDR in the treatment of lung cancers.

  19. Aloe-emodin-mediated photodynamic therapy induces autophagy and apoptosis in human osteosarcoma cell line MG‑63 through the ROS/JNK signaling pathway.

    Science.gov (United States)

    Tu, Pinghua; Huang, Qiu; Ou, Yunsheng; Du, Xing; Li, Kaiting; Tao, Yong; Yin, Hang

    2016-06-01

    The present study was carried out to investigate the effect and mechanisms of aloe‑emodin (AE)-mediated photodynamic therapy (AE-PDT) on the human osteosarcoma cell line MG-63. After treatment with AE-PDT, the human osteosarcoma cell line MG-63 was tested for levels of viability, autophagy, reactive oxygen species (ROS) and apoptosis and changes in cell morphology with the Cell Counting Kit-8 (CCK‑8), monodansylcadaverine (MDC) and Hoechst staining and transmission electron microscopy. The expression of proteins including LC-3, cleaved caspase-3, Beclin-1, Bcl-2, p-JNK, t-JNK and β-actin was examined with western blotting. AE-PDT significantly inhibited the viability of the MG-63 cells in an AE-concentration- and PDT energy density-dependent manner. Autophagy and apoptosis of MG-63 cells was substantially promoted in the AE-PDT group compared to the control group, the AE alone group and the light emitting diode (LED) alone group. Inhibition of autophagy by 3-methyladenine (3-MA) (5 mM) and chloroquine (CQ) (15 µM) significantly promoted the apoptosis rate and improved the sensitivity of the MG-63 cells to AE-PDT. AE-PDT was found to induce the expression of ROS and p-JNK. ROS scavenger, N-acetyl-L-cysteine (NAC, 5 mM), was able to hinder the autophagy, apoptosis and phosphorylation of JNK, and JNK inhibitor (SP600125, 10 µM) significantly inhibited the autophagy and apoptosis, and attenuated the sensitivity of MG63 cells to AE-PDT. In conclusion, AE-PDT induced the autophagy and apoptosis of human osteosarcoma cell line MG-63 through the activation of the ROS-JNK signaling pathway. Autophagy may play a protective role during the early stage following treatment of AE-PDT.

  20. SIRT1 protects cardiac cells against apoptosis induced by zearalenone or its metabolites α- and β-zearalenol through an autophagy-dependent pathway.

    Science.gov (United States)

    Ben Salem, Intidhar; Boussabbeh, Manel; Pires Da Silva, Julie; Guilbert, Arnaud; Bacha, Hassen; Abid-Essefi, Salwa; Lemaire, Christophe

    2017-01-01

    Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium in cereals and agricultural products. The major ZEN metabolites are α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL). In the present study, we investigated the underlying mechanism of the toxicity induced by ZEN, α-ZOL and β-ZOL in cardiac cells (H9c2). We show that treatment with ZEN or its metabolites induces the activation of the mitochondrial pathway of apoptosis as characterized by an increase in ROS generation, a loss of mitochondrial transmembrane potential (ΔΨm) and an activation of caspases. Besides, we demonstrate that these mycotoxins promote the activation of autophagy before the onset of apoptosis. Indeed, we observed that a short-time (6h) treatment with ZEN, α-ZOL or β-ZOL, increased the level of Beclin-1 and LC3-II and induced the accumulation of the CytoID® autophagy detection probe. Moreover, the inhibition of autophagy by Chloroquine significantly increased cell death induced by ZEN, α-ZOL or β-ZOL, suggesting that the activation of autophagy serves as a cardioprotective mechanism against these mycotoxins. In addition, we found that the inhibition (EX527) or the knockdown of SIRT1 (siRNA) significantly increased apoptosis induced by ZEN or its derivatives, whereas SIRT1 activation with RSV greatly prevents the cytotoxic effects of these mycotoxins. By contrast, when autophagy was inhibited by CQ, the activation of SIRT1 by RSV had no protection against the cardiotoxicity of ZEN or its metabolites, suggesting that SIRT1 protects cardiac cells by an autophagy-dependent pathway. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. The ROS/NF-κB/NR4A2 pathway is involved in H2O2 induced apoptosis of resident cardiac stem cells via autophagy.

    Science.gov (United States)

    Shi, Xingxing; Li, Wenjing; Liu, Honghong; Yin, Deling; Zhao, Jing

    2017-09-29

    Cardiac stem cells (CSCs)-based therapy provides a promising avenue for the management of ischemic heart diseases. However, engrafted CSCs are subjected to acute cell apoptosis in the ischemic microenvironment. Here, stem cell antigen 1 positive (Sca-1 + ) CSCs proved to own therapy potential were cultured and treated with H 2 O 2 to mimic the ischemia situation. As autophagy inhibitor, 3-methyladenine (3MA), inhibited H 2 O 2 -induced CSCs apoptosis, thus we demonstrated that H 2 O 2 induced autophagy-dependent apoptosis in CSCs, and continued to find key proteins responsible for the crosstalk between autophagy and apoptosis. Nuclear Receptor Subfamily 4 Group A Member 2 (NR4A2), increased upon cardiomyocyte injury with unknown functions in CSCs, was increased by H 2 O 2 . NR4A2 siRNA attenuated H 2 O 2 induced autophagy and apoptosis in CSCs, which suggested an important role of NR4A2 in CSCs survival in ischemia conditions. Reactive oxygen species (ROS) and NF-κB (P65) subunit were both increased by H 2 O 2 . Either the ROS scavenger, N-acetyl-l-cysteine (NAC) or NF-κB signaling inhibitor, bay11-7082 could attenuate H 2 O 2 -induced autophagy and apoptosis in CSCs, which suggested they were involved in this process. Furthermore, NAC inhibited NF-κB activities, while bay11-7082 inhibited NR4A2 expression, which revealed a ROS/NF-κB/NR4A2 pathway responsible for H 2 O 2 -induced autophagy and apoptosis in CSCs. Our study supports a new clue enhancing the survival rate of CSCs in the infarcted myocardium for cell therapy in ischemic cardiomyopathy.

  2. Role of TFEB Mediated Autophagy, Oxidative Stress, Inflammation, and Cell Death in Endotoxin Induced Myocardial Toxicity of Young and Aged Mice

    Directory of Open Access Journals (Sweden)

    Fang Li

    2016-01-01

    Full Text Available Elderly patients are susceptible to sepsis. LPS induced myocardial injury is a widely used animal model to assess sepsis induced cardiac dysfunction. The age dependent mechanisms behind sepsis susceptibility were not studied. We analyzed age associated changes to cardiac function, cell death, inflammation, oxidative stress, and autophagy in LPS induced myocardial injury. Both young and aged C57BL/6 mice were used for LPS administration. The results demonstrated that LPS induced more cardiac injury (creatine kinase, lactate dehydrogenase, troponin I, and cardiac myosin-light chains 1, cardiac dysfunction (left ventricular inner dimension, LVID, and ejection fraction (EF, cell death, inflammation, and oxidative stress in aged mice compared to young mice. However, a significant age dependent decline in autophagy was observed. Translocation of Transcription Factor EB (TFEB to nucleus and formation of LC3-II were significantly reduced in LPS administered aged mice compared to young ones. In addition to that, downstream effector of TFEB, LAMP-1, was induced in response to LPS challenge in young mice. The present study newly demonstrates that TFEB mediated autophagy is crucial for protection against LPS induced myocardial injury particularly in aging senescent heart. Targeting this autophagy-oxidative stress-inflammation-cell death axis may provide a novel therapeutic strategy for cardioprotection in the elderly.

  3. Cathepsin D protects colorectal cancer cells from acetate-induced apoptosis through autophagy-independent degradation of damaged mitochondria.

    Science.gov (United States)

    Oliveira, C S F; Pereira, H; Alves, S; Castro, L; Baltazar, F; Chaves, S R; Preto, A; Côrte-Real, M

    2015-06-18

    Acetate is a short-chain fatty acid secreted by Propionibacteria from the human intestine, known to induce mitochondrial apoptotic death in colorectal cancer (CRC) cells. We previously established that acetate also induces lysosome membrane permeabilization in CRC cells, associated with release of the lysosomal protease cathepsin D (CatD), which has a well-established role in the mitochondrial apoptotic cascade. Unexpectedly, we showed that CatD has an antiapoptotic role in this process, as pepstatin A (a CatD inhibitor) increased acetate-induced apoptosis. These results mimicked our previous data in the yeast system showing that acetic acid activates a mitochondria-dependent apoptosis process associated with vacuolar membrane permeabilization and release of the vacuolar protease Pep4p, ortholog of mammalian CatD. Indeed, this protease was required for cell survival in a manner dependent on its catalytic activity and for efficient mitochondrial degradation independently of autophagy. In this study, we therefore assessed the role of CatD in acetate-induced mitochondrial alterations. We found that, similar to acetic acid in yeast, acetate-induced apoptosis is not associated with autophagy induction in CRC cells. Moreover, inhibition of CatD with small interfering RNA or pepstatin A enhanced apoptosis associated with higher mitochondrial dysfunction and increased mitochondrial mass. This effect seems to be specific, as inhibition of CatB and CatL with E-64d had no effect, nor were these proteases significantly released to the cytosol during acetate-induced apoptosis. Using yeast cells, we further show that the role of Pep4p in mitochondrial degradation depends on its protease activity and is complemented by CatD, indicating that this mechanism is conserved. In summary, the clues provided by the yeast model unveiled a novel CatD function in the degradation of damaged mitochondria when autophagy is impaired, which protects CRC cells from acetate-induced apoptosis. Cat

  4. Toxic metals and autophagy.

    Science.gov (United States)

    Chatterjee, Sarmishtha; Sarkar, Shuvasree; Bhattacharya, Shelley

    2014-11-17

    The earth's resources are finite, and it can no longer be considered a source of inexhaustible bounty for the human population. However, this realization has not been able to contain the human desire for rapid industrialization. The collateral to overusing environmental resources is the high-level contamination of undesirable toxic metals, leading to bioaccumulation and cellular damage. Cytopathological features of biological systems represent a key variable in several diseases. A review of the literature revealed that autophagy (PCDII), a high-capacity process, may consist of selective elimination of vital organelles and/or proteins that intiate mechanisms of cytoprotection and homeostasis in different biological systems under normal physiological and stress conditions. However, the biological system does survive under various environmental stressors. Currently, there is no consensus that specifies a particular response as being a dependable biomarker of toxicology. Autophagy has been recorded as the initial response of a cell to a toxic metal in a concentration- and time-dependent manner. Various signaling pathways are triggered through cellular proteins and/or protein kinases that can lead to autophagy, apoptosis (or necroptosis), and necrosis. Although the role of autophagy in tumorigenesis is associated with promoting tumor cell survival and/or acting as a tumor suppressive mechanism, PCDII in metal-induced toxicity has not been extensively studied. The aim of this review is to analyze the comparative cytotoxicity of metals/metalloids and nanoparticles (As, Cd, Cr, Hg, Fe, and metal-NP) in cells enduring autophagy. It is noted that metals/metalloids and nanoparticles prefer ATG8/LC3 as a potent inducer of autophagy in several cell lines or animal cells. MAP kinases, death protein kinases, PI3K, AKT, mTOR, and AMP kinase have been found to be the major components of autophagy induction or inhibition in the context of cellular responses to metals/metalloids and

  5. Autophagy induction by Bcr-Abl-expressing cells facilitates their recovery from a targeted or nontargeted treatment.

    LENUS (Irish Health Repository)

    Crowley, Lisa C

    2012-01-31

    Although Imatinib has transformed the treatment of chronic myeloid leukemia (CML), it is not curative due to the persistence of resistant cells that can regenerate the disease. We have examined how Bcr-Abl-expressing cells respond to two mechanistically different therapeutic agents, etoposide and Imatinib. We also examined Bcr-Abl expression at low and high levels as elevated expression has been associated with treatment failure. Cells expressing low levels of Bcr-Abl undergo apoptosis in response to the DNA-targeting agent (etoposide), whereas high-Bcr-Abl-expressing cells primarily induce autophagy. Autophagic populations engage a delayed nonapoptotic death; however, sufficient cells evade this and repopulate following the withdrawal of the drug. Non-Bcr-Abl-expressing 32D or Ba\\/F3 cells induce both apoptosis and autophagy in response to etoposide and can recover. Imatinib treatment induces both apoptosis and autophagy in all Bcr-Abl-expressing cells and populations rapidly recover. Inhibition of autophagy with ATG7 and Beclin1 siRNA significantly reduced the recovery of Imatinib-treated K562 cells, indicating the importance of autophagy for the recovery of treated cells. Combination regimes incorporating agents that disrupt Imatinib-induced autophagy would remain primarily targeted and may improve response to the treatment in CML.

  6. Autophagy Inhibition Enhances the Mitochondrial-Mediated Apoptosis Induced by Mangrove (Avicennia marina) Extract in Human Breast Cancer Cells

    KAUST Repository

    Esau, Luke

    2015-01-10

    Aims: Avicennia marina (AM) is a widely distributed mangrove plant that has been used in traditional medicine for centuries for the treatment of a number of diseases. The objective of the present study was to evaluate the leaf ethyl acetate extract of AM for its cytotoxic and apoptotic potential along with in-depth investigations of its mechanism of action in breast cancer MCF-7 cells. Study Design: The ethyl acetate extract of leaves and stems of AM was tested against estrogen positive breast cancer cell line MCF-7 using various assays. Place and Duration of Study: The study was carried out at King Abdullah University of Science and Technology, Thuwal, Saudi Arabia, from July 2013-June 2014. Methodology: Dose- and time-dependent growth inhibition of cancer cells was measured using MTT assay. The mechanisms of apoptosis induction were determined using various assays: phosphatidylserine exposure, caspase-3/7 activation, mitochondrial membrane potential disruption, reactive oxygen species (ROS) production, cell cycle analysis, autophagy, and protein expression using western blotting. The modulation of apoptotic genes (p53, Mdm2, NF-kB, Bad, Bax, Bcl-2 and Casp7) was also determined using real time PCR. Results: The AM extract inhibited breast cancer cell growth and induced apoptosis in a concentration dependent manner. We demonstrated a non-classical mode of apoptosis induction in MCF-7 cells by AM extract, where ROS production altered the mitochondrial membrane potential to induce apoptosis. Breast cancer cells treated with 200 µg/ml concentration of AM extract showed increased ROS production and disrupted MMP but no PARP-1 cleavage and a marked decrease in Caspase-7 protein levels (24 and 48 h) were detected. A significant amount of autophagy was also observed at the same concentration. However, treatment of MCF-7 cells with 200 µg/ml of AM extract along with the inhibition of autophagy by chloroquine, significantly increased the apoptosis from 20% to 45

  7. Cadmium induces BNIP3-dependent autophagy in chicken spleen by modulating miR-33-AMPK axis.

    Science.gov (United States)

    Chen, Menghao; Li, Xiaojing; Fan, Ruifeng; Yang, Jie; Jin, Xi; Hamid, Sattar; Xu, Shiwen

    2018-03-01

    Cadmium (Cd), a widespread environmental pollutant, has toxic effects on organs including spleen. However, the underlying mechanisms of Cd induced spleen toxicity and the roles of micro-RNA (miRNA) in this process remain poorly understood. To investigate this, cadmium chloride (CdCl 2 , 10 mg/kg) was administered in the diet of chickens for 90 days. Electron microscopy, qPCR and Western blot were performed. Results showed that Cd exposure suppressed miR-33-5q which increased the levels of AMPK. Subsequently, significant decrease in AKT/mTOR signaling and HSP70 were observed. Concurrently, levels of NF-κB, p-JNK/JNK increased significantly. Moreover, the expression of BNIP3 and other autophagy markers (LC3-I, LC3-II, Beclin-1) increased significantly. Additionally, the levels of ions (Ca, Cr, Se, Sr, Sn, Ba) and (Na, Mg, V, Fe, Mo, Cu, Zn, Cd) significantly decreased and increased, respectively. Taken together, we conclude that Cd induced the deregulation of miR-33-AMPK axis led to BNIP3-dependent autophagy in chicken spleen through AKT/mTOR and HSP70-NF-κB/JNK signal pathways. In-addition Cd could affect ion homeostasis in chicken spleen. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Increased cell survival of cells exposed to superparamagnetic iron oxide nanoparticles through biomaterial substrate-induced autophagy.

    Science.gov (United States)

    Tseng, Ting-Chen; Hsieh, Fu-Yu; Hsu, Shan-Hui

    2016-04-01

    The cellular uptake of nanoparticles (NPs) can be promoted by NP surface modification but cell viability is often sacrificed. Our previous study has shown that intracellular uptake of iron oxide NPs was significantly increased for cells cultured on chitosan. However, the mechanism for having the higher cellular uptake as well as better cell survival on the chitosan surface remains unclear. In this study, we sought to clarify if the autophagic response may contribute to cell survival under excessive NP exposure conditions on chitosan. L929 fibroblasts and neural stem cells (NSCs) were challenged with different concentrations (0-300 μg ml(-1)) of superparamagnetic iron oxide NPs. The autophagic response as well as the metabolic activity of cells was evaluated. Results showed that culturing both types of cells on chitosan substrates significantly enhanced the cellular uptake of NPs. At higher NP concentrations, cells on chitosan showed a greater survival rate than those on TCPS. The expression levels of autophagy-related genes (Atg5 and Atg7 genes) and autophagy associated protein (LC3-II) on chitosan were higher than that on TCPS. The NP exposure further increased the expressions. We suggest that cells cultured on chitosan were more tolerant to NP cytotoxicity because of the increased autophagic response. Moreover, NP exposure increased the metabolic activity of cells grown on chitosan, while it decreased the metabolism of cells cultured on TCPS. In animal studies, iron oxide-labeled NSCs were injected in zebrafish embryos. Results also showed that cells grown on chitosan had better survival after transplantation than those grown on TCPS. Taken together, chitosan as a culture substrate can induce cell autophagy to increase cell survival in particular for NP-labeled cells. This will be valuable for the biomedical application of NPs in cell therapy.

  9. Swimming attenuates d-galactose-induced brain aging via suppressing miR-34a-mediated autophagy impairment and abnormal mitochondrial dynamics.

    Science.gov (United States)

    Kou, Xianjuan; Li, Jie; Liu, Xingran; Chang, Jingru; Zhao, Qingxia; Jia, Shaohui; Fan, Jingjing; Chen, Ning

    2017-06-01

    microRNAs (miRNAs) have been reported to be involved in many neurodegenerative diseases. To explore the regulatory role of miR-34a in aging-related diseases such as Alzheimer's disease (AD) during exercise intervention, we constructed a rat model with d-galactose (d-gal)-induced oxidative stress and cognitive impairment coupled with dysfunctional autophagy and abnormal mitochondrial dynamics, determined the mitigation of cognitive impairment of d-gal-induced aging rats during swimming intervention, and evaluated miR-34a-mediated functional status of autophagy and abnormal mitochondrial dynamics. Meanwhile, whether the upregulation of miR-34a can lead to dysfunctional autophagy and abnormal mitochondrial dynamics was confirmed in human SH-SY5Y cells with silenced miR-34a by the transfection of a miR-34a inhibitor. Results indicated that swimming intervention could significantly attenuate cognitive impairment, prevent the upregulation of miR-34a, mitigate the dysfunctional autophagy, and inhibit the increase of dynamin-related protein 1 (DRP1) in d-gal-induced aging model rats. In contrast, the miR-34a inhibitor in cell model not only attenuated D-gal-induced the impairment of autophagy but also decreased the expression of DRP1 and mitofusin 2 (MFN2). Therefore, swimming training can delay brain aging of d-gal-induced aging rats through attenuating the impairment of miR-34a-mediated autophagy and abnormal mitochondrial dynamics, and miR-34a could be the novel therapeutic target for aging-related diseases such as AD. NEW & NOTEWORTHY In the present study, we have found that the upregulation of miR-34a is the hallmark of aging or aging-related diseases, which can result in dysfunctional autophagy and abnormal mitochondrial dynamics. In contrast, swimming intervention can delay the aging process by rescuing the impaired functional status of autophagy and abnormal mitochondrial dynamics via the suppression of miR-34a. Copyright © 2017 the American Physiological Society.

  10. Endosome-mediated autophagy

    Science.gov (United States)

    Kondylis, Vangelis; van Nispen tot Pannerden, Hezder E.; van Dijk, Suzanne; ten Broeke, Toine; Wubbolts, Richard; Geerts, Willie J.; Seinen, Cor; Mutis, Tuna; Heijnen, Harry F.G.

    2013-01-01

    Activation of TLR signaling has been shown to induce autophagy in antigen-presenting cells (APCs). Using high-resolution microscopy approaches, we show that in LPS-stimulated dendritic cells (DCs), autophagosomes emerge from MHC class II compartments (MIICs) and harbor both the molecular machinery for antigen processing and the autophagosome markers LC3 and ATG16L1. This ENdosome-Mediated Autophagy (ENMA) appears to be the major type of autophagy in DCs, as similar structures were observed upon established autophagy-inducing conditions (nutrient deprivation, rapamycin) and under basal conditions in the presence of bafilomycin A1. Autophagosome formation was not significantly affected in DCs expressing ATG4BC74A mutant and atg4b−/− bone marrow DCs, but the degradation of the autophagy substrate SQSTM1/p62 was largely impaired. Furthermore, we demonstrate that the previously described DC aggresome-like LPS-induced structures (DALIS) contain vesicular membranes, and in addition to SQSTM1 and ubiquitin, they are positive for LC3. LC3 localization on DALIS is independent of its lipidation. MIIC-driven autophagosomes preferentially engulf the LPS-induced SQSTM1-positive DALIS, which become later degraded in autolysosomes. DALIS-associated membranes also contain ATG16L1, ATG9 and the Q-SNARE VTI1B, suggesting that they may represent (at least in part) a membrane reservoir for autophagosome expansion. We propose that ENMA constitutes an unconventional, APC-specific type of autophagy, which mediates the processing and presentation of cytosolic antigens by MHC class II machinery, and/or the selective clearance of toxic by-products of elevated ROS/RNS production in activated DCs, thereby promoting their survival. PMID:23481895

  11. 3′-epi-12β-hydroxyfroside, a new cardenolide, induces cytoprotective autophagy via blocking the Hsp90/Akt/mTOR axis in lung cancer cells

    Science.gov (United States)

    Sun, Yan; Huang, Yong-Hao; Huang, Feng-Ying; Mei, Wen-Li; Liu, Quan; Wang, Cai-Chun; Lin, Ying-Ying; Huang, Canhua; Li, Yue-Nan; Dai, Hao-Fu; Tan, Guang-Hong

    2018-01-01

    Rationale: Cardenolides have potential as anticancer drugs. 3′-epi-12β-hydroxyfroside (HyFS) is a new cardenolide structure isolated by our research group, but its molecular mechanisms remain poorly understood. This study investigates the relationship between its antitumor activities and autophagy in lung cancer cells. Methods: Cell growth and proliferation were detected by MTT, lactate dehydrogenase (LDH) release, 5-ethynyl-20-deoxyuridine (EDU) and colony formation assays. Cell apoptosis was detected by flow cytometry. Autophagic and signal proteins were detected by Western blotting. Markers of autophagy and autophagy flux were also detected by immunofluorescence, transmission electron microscopy and acridine orange staining. Real time RT-PCR was used to analyze the gene expression of Hsp90. Hsp90 ubiquitination was detected by coimmunoprecipitation. The antitumore activities of HyFS were observed in nude mice. Results: HyFS treatment inhibited cell proliferation and induced autophagy in A549 and H460 lung cancer cells, but stronger inhibition of cell proliferation and induction of cell apoptosis were shown when HyFS-mediated autophagy was blocked. The Hsp90/Akt/mTOR axis was found to be involved in the activation of HyFS-mediated autophagy. Evidence of direct interaction between Hsp90 and Akt was observed. HyFS treatment resulted in decreased levels of heat shock protein 90 (Hsp90) and phosphorylated Akt, overexpression of Hsp90 increased activation of autophagy, and inhibition of Hsp90 expression decreased autophagy. In addition, ubiquitin-mediated degradation of Hsp90 and subsequent dephosphorylation of its client protein Akt were also found in HyFS-treated lung cancer cells. Moreover, combination treatment with HyFS and chloroquine showed remarkably increased tumor inhibition in both A549- and H460-bearing mice. Conclusion: Our results demonstrate that HyFS induced cytoprotective autophagy through ubiquitin-mediated degradation of Hsp90, which further

  12. Aliskiren Improves Ischemia- and Oxygen Glucose Deprivation-Induced Cardiac Injury through Activation of Autophagy and AMP-Activated Protein Kinase

    Directory of Open Access Journals (Sweden)

    Ming-Hsien Chiang

    2017-11-01

    Full Text Available Aliskiren is a direct renin inhibitor that has been effective in anti-hypertension. We investigated whether aliskiren could improve the ischemia-induced cardiac injury and whether the autophagy was involved in this effect. A myocardial infarction (MI model was created by the ligation of the left anterior coronary artery in C57J/BL6 mice. They were treated for 1, 3, 7, and 14 days with vehicle or aliskiren (25 mg/kg/day via subcutaneous injection. In vivo, the MI mice exhibited worse cardiac function by echocardiographic assessment and showed larger myocardial scarring by light microscopy, whereas aliskiren treatment reversed these effects, which were also associated with the changes in caspase-3 and Bcl-2 expression as well as in the number of apoptotic cells. Aliskiren increased autophagy, as demonstrated by LC3B-II expression and transmission electron microscopy. Furthermore, H9c2 cardiomyocytes were employed as an in vitro model to examine the effects of aliskiren on apoptosis and autophagy under oxygen glucose deprivation (OGD-induced injury. Aliskiren significantly increased cell viability in a dose-dependent manner. The beneficial effects of aliskiren were associated with decreased apoptosis and mitochondrial membrane potential as well as increased autophagy via increased autophagosome formation. We also found that aliskiren-induced cardiomyocyte survival occurred via AMP-activated protein kinase (AMPK-dependent autophagy. Taken together, these results indicated that aliskiren increased cardiomyocyte survival through increased autophagosomal formation and decreased apoptosis and necrosis via modulating AMPK expression. AMPK-dependent autophagy may represent a novel mechanism for aliskiren in ischemic cardiac disease therapy.

  13. Linc-ROR confers gemcitabine resistance to pancreatic cancer cells via inducing autophagy and modulating the miR-124/PTBP1/PKM2 axis.

    Science.gov (United States)

    Li, Chenggang; Zhao, Zhiming; Zhou, Zhipeng; Liu, Rong

    2016-12-01

    In this study, we investigated the regulation of linc-ROR on autophagy and gemcitabine resistance of pancreatic cancer cells and further studied the underlying involvement of the miR-124/PTBP1/PKM2 axis in this regulation. Pancreatic cancer cell lines PANC-1 and MIAPaCa-2 cells were used as in vitro model. Autophagy was assessed by western blot of LC3 I/II and observation GFP-LC3 puncta. Cell viability was examined using CCK-8 assay. Cell apoptosis was examined by flow cytometric analysis of Annexin V/PI staining. QRT-PCR, RNA fluorescence in situ hybridization and dual luciferase assay were used to study the expression and the binding between linc-ROR and miR-124. Linc-ROR siRNA significantly sensitized PANC-1 and MIAPaCa-2 cells to gemcitabine, while linc-ROR overexpression significantly reduced the sensitivity. Linc-ROR knockdown reduced basal autophagy, while linc-ROR overexpression markedly increased basal autophagy in the cells. Linc-ROR siRNA showed similar effect as 3-MA on enhancing gemcitabine-induced cell apoptosis and also reduced PKM2 expression. MiR-124 overexpression restored PKM1 and reduced PKM2 levels in the cells. In addition, miR-124 mimics also alleviated autophagy in pancreatic cancer cells. Both miR-124 mimics and PKM2 siRNA enhanced gemcitabine-induced cell apoptosis. In both pancreatic cell lines and PADC tissues, linc-ROR is negatively correlated with miR-124 expression. In addition, dual luciferase assay verified two 8mer binding sites between miR-124 and linc-ROR. Linc-ROR confers gemcitabine resistance to pancreatic cancer cells at least partly via inducing autophagy. There is a linc-ROR/miR-124/PTBP1/PKM2 axis involved in regulation of gemcitabine resistance in pancreatic cancer cells.

  14. A comparative study of changes of autophagy in rat models of CLP versus LPS induced sepsis.

    Science.gov (United States)

    Zhang, Binglun; Liu, Chunfeng; Yang, Ni; Wang, Xiangdie

    2017-09-01

    In the present study, two different rat models of sepsis, cecal ligation and puncture (CLP), and lipopolysaccharide (LPS), were established. Changes in autophagy in both models were compared using transmission electron microscopy (TEM), immunohistochemistry, western blotting, and quantitative polymerase chain reaction techniques. Consequently, TEM analysis revealed autophagic bodies in the CLP and LPS sepsis models. In addition, autophagy-related protein LC3 A-specific staining was detected in the cytoplasm. However, analysis of protein and gene expression levels revealed a statistically significant increase in autophagic activity 12 and 24 h following induction of the CLP group, and 2 h following induction of the LPS group. Thus, it was concluded that both models of sepsis exhibited increased autophagic activity of the cardiomyocytes over time. The LPS model was superior to the CLP model in perturbation of molecular biological mechanisms, while the latter would be more likely suited for the study of physiological functions.

  15. Phosphoproteomic analysis of cells treated with longevity-related autophagy inducers

    DEFF Research Database (Denmark)

    Bennetzen, Martin V; Mariño, Guillermo; Pultz, Dennis

    2012-01-01

    Macroautophagy is a self-cannibalistic process that enables cells to adapt to various stresses and maintain energy homeostasis. Additionally, autophagy is an important route for turnover of misfolded proteins and damaged organelles, with important implications in cancer, neurodegenerative diseases...... to resveratrol and spermidine and that key proteins modulating the acetylation, phosphorylation, methylation and ubiquitination status were affected by changes in phosphorylation during the autophagic response. Essential parts of the apoptotic signaling network were subjected to post-translational modifications...

  16. Inhibition of long non-coding RNA ROR reverses resistance to Tamoxifen by inducing autophagy in breast cancer.

    Science.gov (United States)

    Li, Yuehua; Jiang, Baohong; Zhu, Hongbo; Qu, Xiaofei; Zhao, Liqin; Tan, Yeru; Jiang, Yiling; Liao, Mingchu; Wu, Xiaoping

    2017-06-01

    proliferation, invasion, and migration in the siROR + Tamoxifen group were much decreased; these results implied that downregulated long non-coding RNA ROR suppressed BT474 cell proliferation, invasion, and migration and reversed the effect of Tamoxifen on the BT474 cells. These results indicate that inhibition of long non-coding RNA ROR reverses resistance to Tamoxifen by inducing autophagy in breast cancer.

  17. Escin induces caspase-dependent apoptosis and autophagy through the ROS/p38 MAPK signalling pathway in human osteosarcoma cells in vitro and in vivo.

    Science.gov (United States)

    Zhu, Jian; Yu, Wei; Liu, Bing; Wang, Yitian; Shao, Jianlin; Wang, Junjie; Xia, Kaishun; Liang, Chengzhen; Fang, Weijing; Zhou, Chenhe; Tao, Huimin

    2017-10-12

    Osteosarcoma is one of the most malignant neoplasms in adolescents, and it generally develops multidrug resistance. Escin, a natural mixture of triterpene saponins isolated from Aesculus hippocastanum (horse chestnut), has demonstrated potent anti-tumour potential in vitro and in vivo. In the present study, we found that escin inhibited osteosarcoma proliferation in a dose- and time-dependent manner. Additionally, escin-induced apoptosis was evidenced by the increased expression of caspase-related proteins and the formation of apoptotic bodies. Escin also induced autophagy, with elevated LC3, ATG5, ATG12 and Beclin expression as well as autophagosome formation. Inhibition of escin-induced autophagy promoted apoptosis. Moreover, p38 mitogen-activated protein kinases (MAPKs) and reactive oxygen species (ROS) were activated by escin. A p38 MAPK inhibitor partially attenuated the autophagy and apoptosis triggered by escin, but a ROS scavenger showed a greater inhibitory effect. Finally, the therapeutic efficacy of escin against osteosarcoma was demonstrated in an orthotopic model. Overall, escin counteracted osteosarcoma by inducing autophagy and apoptosis via the activation of the ROS/p38 MAPK signalling pathway; these findings provide evidence for escin as a novel and potent therapeutic for the treatment of osteosarcoma.

  18. RelA-Mediated BECN1 Expression Is Required for Reactive Oxygen Species-Induced Autophagy in Oral Cancer Cells Exposed to Low-Power Laser Irradiation.

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    Chih-Wen Shu

    Full Text Available Low-power laser irradiation (LPLI is a non-invasive and safe method for cancer treatment that alters a variety of physiological processes in the cells. Autophagy can play either a cytoprotective role or a detrimental role in cancer cells exposed to stress. The detailed mechanisms of autophagy and its role on cytotoxicity in oral cancer cells exposed to LPLI remain unclear. In this study, we showed that LPLI at 810 nm with energy density 60 J/cm2 increased the number of microtubule associated protein 1 light chain 3 (MAP1LC3 puncta and increased autophagic flux in oral cancer cells. Moreover, reactive oxygen species (ROS production was induced, which increased RelA transcriptional activity and beclin 1 (BECN1 expression in oral cancer cells irradiated with LPLI. Furthermore, ROS scavenger or knockdown of RelA diminished LPLI-induced BECN1 expression and MAP1LC3-II conversion. In addition, pharmacological and genetic ablation of autophagy significantly enhanced the effects of LPLI-induced apoptosis in oral cancer cells. These results suggest that autophagy may be a resistant mechanism for LPLI-induced apoptosis in oral cancer cells.

  19. 3-Anhydro-6-hydroxy-ophiobolin A, a fungal sesterterpene from Bipolaris oryzae induced autophagy and promoted the degradation of α-synuclein in PC12 cells.

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    Xue, Danfeng; Wang, Quanxin; Chen, Ziheng; Cai, Lei; Bao, Li; Qi, Qiuyue; Liu, Lei; Wang, Xiaohui; Jin, Haijing; Wang, Jun; Wu, Hao; Liu, Hongwei; Chen, Quan

    2015-04-01

    Autophagy is defined as an evolutionarily conserved process responsible for degradation of the cytoplasmic components including protein aggregates via the lysosomal machinery. Increasing evidence has linked defective autophagic degradation of protein aggregates with the pathogenesis of neurodegenerative disorders, and it is suggested that promotion of autophagy is regarded as a potential therapeutic for these diseases including Parkinson's disease (PD). Here we identified, 3-anhydro-6-hydroxy-ophiobolin A (X15-2), an ophiobolin derivative from Bipolaris oryzae that can strongly induce autophagic degradation of α-synuclein, the major constituent of Lewy bodies. We showed that X15-2 induced autophagy is dependent on both Beclin1 and Beclin2. Knockout of ATG5 by CRISPER/Cas9 prevented X15-2 induced autophagy and degradation of α-synuclein. Mechanistically, we showed that X15-2 induces ROS and the activation of JNK signaling for the autophagic degradation of α-synuclein in PC12 cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Autophagy Regulates Proteasome Inhibitor-Induced Pigmentation in Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells.

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    Juuti-Uusitalo, Kati; Koskela, Ali; Kivinen, Niko; Viiri, Johanna; Hyttinen, Juha M T; Reinisalo, Mika; Koistinen, Arto; Uusitalo, Hannu; Sinha, Debasish; Skottman, Heli; Kaarniranta, Kai

    2017-05-19

    The impairment of autophagic and proteasomal cleansing together with changes in pigmentation has been documented in retinal pigment epithelial (RPE) cell degeneration. However, the function and co-operation of these mechanisms in melanosome-containing RPE cells is still unclear. We show that inhibition of proteasomal degradation with MG-132 or autophagy with bafilomycin A1 increased the accumulation of premelanosomes and autophagic structures in human embryonic stem cell (hESC)-derived RPE cells. Consequently, upregulation of the autophagy marker p62 (also known as sequestosome-1, SQSTM1) was confirmed in Western blot and perinuclear staining. Interestingly, cells treated with the adenosine monophosphatedependent protein kinase activator, AICAR (5-Aminoimidazole-4-carboxamide ribonucleotide), decreased the proteasome inhibitor-induced accumulation of premelanosomes, increased the amount of autophagosomes and eradicated the protein expression of p62 and LC3 (microtubule-associated protein 1A/1B-light chain 3). These results revealed that autophagic machinery is functional in hESC-RPE cells and may regulate cellular pigmentation with proteasomes.

  1. Ameliorative effects of selenium on arsenic-induced cytotoxicity in PC12 cells via modulating autophagy/apoptosis.

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    Rahman, Md Mostafizur; Uson-Lopez, Rachael A; Sikder, Md Tajuddin; Tan, Gongxun; Hosokawa, Toshiyuki; Saito, Takeshi; Kurasaki, Masaaki

    2018-04-01

    Arsenic is well known toxicant responsible for human diseases including cancers. On the other hand, selenium is an essential trace element with significant chemopreventive effects, anticancer potentials and antioxidant properties. Although previous studies have reported antagonism/synergism between arsenic and selenium in biological systems, the biomolecular mechanism/s is still inconclusive. Therefore, to elucidate the molecular phenomena in cellular level, we hypothesized that co-exposure of selenium with arsenic may have suppressive effects on arsenic-induced cytotoxicity. We found that selenium in co-exposure with arsenic increases cell viability, and suppresses oxidative stress induced by arsenic in PC12 cells. Consequently, DNA fragmentation due to arsenic exposure was also reduced by arsenic and selenium co-exposure. Furthermore, western blot analyses revealed that simultaneous exposure of both metals significantly inhibited autophagy which further suppressed apoptosis through positively regulation of key proteins; p-mTOR, p-Akt, p-Foxo1A, p62, and expression of ubiquitin, Bax, Bcl2, NFкB, and caspases 3 and 9, although those are negatively regulated by arsenic. In addition, reverse transcriptase PCR analysis confirmed the involvement of caspase cascade in cell death process induced by arsenic and subsequent inhibition by co-exposure of selenium with arsenic. The cellular accumulation study of arsenic in presence/absence of selenium via inductively coupled plasma mass spectrometry confirmed that selenium effectively retarded the uptake of arsenic in PC12 cells. Finally, these findings imply that selenium is capable to modulate arsenic-induced intrinsic apoptosis pathway via enhancement of mTOR/Akt autophagy signaling pathway through employing antioxidant potentials and through inhibiting the cellular accumulation of arsenic in PC12 cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. HucMSC exosomes-delivered 14-3-3ζ enhanced autophagy via modulation of ATG16L in preventing cisplatin-induced acute kidney injury.

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    Jia, Haoyuan; Liu, Wanzhu; Zhang, Bin; Wang, Juanjuan; Wu, Peipei; Tandra, Nitin; Liang, Zhaofeng; Ji, Cheng; Yin, Lei; Hu, Xinyuan; Yan, Yongmin; Mao, Fei; Zhang, Xu; Yu, Jing; Xu, Wenrong; Qian, Hui

    2018-01-01

    The clinical application of cisplatin is restricted by its side effects of nephrotoxicity. Human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-ex) have an important effect in tissue injury repair. Our previous work discovered that pretreatment with human umbilical cord mesenchymal stem cell-derived exosomes (hucMSC-ex) alleviated cisplatin-induced acute kidney injury (AKI) by activating autophagy both in vitro and in vivo . In this study, we further explored the mechanisms of hucMSC-ex in autophagy for preventing cisplatin-induced nephrotoxicity. We discovered that 14-3-3ζ was contained in hucMSC-ex, and knockdown and overexpression 14-3-3ζ reduced and enhanced the autophagic activity respectively. Furthermore, Knockdown of 14-3-3ζ alleviated the preventive effect of hucMSC-ex. In contrast, overexpression of 14-3-3ζ enhanced the effect. Further results confirmed that hucMSC-ex increased ATG16L expression and that 14-3-3ζ interacted with ATG16L, promoting the localization of ATG16L at autophagosome precursors. In this study, we revealed that hucMSC-ex-delivered 14-3-3ζ interacted with ATG16L to activate autophagy. Our findings suggest that 14-3-3ζ is a novel mechanism for MSC-exosomes-activated autophagy and provides a new strategy for the prevention of cisplatin-induced nephrotoxicity.

  3. Koelreuteria Formosana Extract Induces Growth Inhibition and Cell Death in Human Colon Carcinoma Cells via G2/M Arrest and LC3-II Activation-Dependent Autophagy.

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    Horng, Chi-Ting; Wu, Yueh-Jung; Chen, Pei-Ni; Chu, Shu-Chen; Tsai, Chun-Miao; Hsieh, Yih-Shou

    2017-01-01

    Autophagy is a self-destructive process that degrades cytoplasmic constituents. In our previous study, Koelreuteria formosana ethanolic extract (KFEE), which is obtained from natural plants endemic to Taiwan, has inhibited cell metastasis in renal carcinoma cells. However, the anticancer effects of KFEE on colon cancer remain unclear. In this study, KFEE exerted a strong cytotoxic effect on DLD-1 and COLO 205 human colorectal cancer cell lines. KFEE effectively inhibited cancer cell proliferation, induced G2/M-phase arrest associated with downregulaton of cyclin E, cyclin B and cdc25C and upregulation of p21, and induced cell death by activating autophagy but did not cause apoptotic cell death. Exposed KFEE cells showed increased levels of acridine orange, autophagic vacuoles, and LC3-II proteins, which are specific autophagic markers. Bcl-2, p-Akt, and p-mTOR levels, which have been implicated in autophagic downregulation, were decreased after KFEE treatment. Autophagy inhibitor 3-methyladenosine and bafilomycin-A1 and genetic silencing of LC3 attenuated KFEE-induced growth inhibition. These findings suggested that KFEE causes cytostatic effect through autophagy. In xenograft studies, oral administration of KFEE had significantly inhibited the tumor growth in nude mice that had received subcutaneous injection of DLD-1 cells. KFEE is a promising candidate in phytochemical-based, mechanistic, and pathway-targeted cancer prevention strategies.

  4. Chronic Caloric Restriction and Exercise Improve Metabolic Conditions of Dietary-Induced Obese Mice in Autophagy Correlated Manner without Involving AMPK

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    Mingxia Cui

    2013-01-01

    Full Text Available Aim. To investigate the role of AMPK activation and autophagy in mediating the beneficial effects of exercise and caloric restriction in obesity. Methods. Dietary-induced obesity mice were made and divided into 5 groups; one additional group of normal mice serves as control. Mice in each group received different combinations of interventions including low fat diet, caloric restriction, and exercise. Then their metabolic conditions were assessed by measuring serum glucose and insulin, serum lipids, and liver function. AMPK phosphorylation and autophagy activity were detected by western blotting. Results. Obese mice models were successfully induced by high fat diet. Caloric restriction consistently improved the metabolic conditions of the obese mice, and the effects are more prominent than the mice that received only exercise. Also, caloric restriction, exercise, and low fat diet showed a synergistic effect in the improvement of metabolic conditions. Western blotting results showed that this improvement was not related with the activation of AMPK in liver, skeletal muscle, or heart but correlates well with the autophagy activity. Conclusion. Caloric restriction has more prominent beneficial effects than exercise in dietary-induced obese mice. These effects are correlated with the autophagy activity and may be independent of AMPK activation.

  5. The pan-inhibitor of Aurora kinases danusertib induces apoptosis and autophagy and suppresses epithelial-to-mesenchymal transition in human breast cancer cells

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    Li JP

    2015-02-01

    , but its antitumor effect and underlying mechanisms in the treatment of human breast cancer remain elusive. This study aimed to investigate the effects of Danu on the growth, apoptosis, autophagy, and epithelial-to-mesenchymal transition (EMT and the molecular mechanisms in human breast cancer MCF7 and MDA-MB-231 cells. The results demonstrated that Danu remarkably inhibited cell proliferation, induced apoptosis and autophagy, and suppressed EMT in both breast cancer cell lines. Danu arrested MCF7 and MDA-MB-231 cells in G2/M phase, accompanied by the downregulation of cyclin-dependent kinase 1 and cyclin B1 and upregulation of p21 Waf1/Cip1, p27 Kip1, and p53. Danu significantly decreased the expression of B-cell lymphoma-extra-large (Bcl-xl and B-cell lymphoma 2 (Bcl-2, but increased the expression of Bcl-2-associated X protein (Bax and p53-upregulated modulator of apoptosis (PUMA, and promoted the cleavage of caspases 3 and 9. Furthermore, Danu significantly increased the expression levels of the membrane-bound microtubule-associated protein 1A/1B-light chain 3 (LC3-II and beclin 1 in breast cancer cells, two markers for autophagy. Danu induced the activation of p38 mitogen-activated protein kinase (MAPK and extracellular signal-regulated kinases 1 and 2 (Erk1/2 and inhibited the activation of protein kinase B (Akt/mammalian target of rapamycin (mTOR signaling pathways in breast cancer cells. Treatment with wortmannin (a phosphatidylinositol 3-kinase inhibitor markedly inhibited Danu-induced activation of p38 MAPK and conversion of cytosolic LC3-I to membrane-bound LC3-II. Pharmacological inhibition and small interfering RNA-mediated knockdown of p38 MAPK suppressed Akt activation, resulting in LC3-II accumulation and enhanced autophagy. Pharmacological inhibition and small interfering RNA-mediated knockdown of Erk1/2 also remarkably increased the level of LC3-II in MCF7 cells. Moreover, Danu inhibited EMT in both MCF7 and MDA-MB-231 cells with upregulated E

  6. Cold stress accentuates pressure overload-induced cardiac hypertrophy and contractile dysfunction: role of TRPV1/AMPK-mediated autophagy.

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    Lu, Songhe; Xu, Dezhong

    2013-12-06

    Severe cold exposure and pressure overload are both known to prompt oxidative stress and pathological alterations in the heart although the interplay between the two remains elusive. Transient receptor potential vanilloid 1 (TRPV1) is a nonselective cation channel activated in response to a variety of exogenous and endogenous physical and chemical stimuli including heat and capsaicin. The aim of this study was to examine the impact of cold exposure on pressure overload-induced cardiac pathological changes and the mechanism involved. Adult male C57 mice were subjected to abdominal aortic constriction (AAC) prior to exposure to cold temperature (4 °C) for 4 weeks. Cardiac geometry and function, levels of TRPV1, mitochondrial, and autophagy-associated proteins including AMPK, mTOR, LC3B, and P62 were evaluated. Sustained cold stress triggered cardiac hypertrophy, compromised depressed myocardial contractile capacity including lessened fractional shortening, peak shortening, and maximal velocity of shortening/relengthening, enhanced ROS production, and mitochondrial injury, the effects of which were negated by the TRPV1 antagonist SB366791. Western blot analysis revealed upregulated TRPV1 level and AMPK phosphorylation, enhanced ratio of LC3II/LC3I, and downregulated P62 following cold exposure. Cold exposure significantly augmented AAC-induced changes in TRPV1, phosphorylation of AMPK, LC3 isoform switch, and p62, the effects of which were negated by SB366791. In summary, these data suggest that cold exposure accentuates pressure overload-induced cardiac hypertrophy and contractile defect possibly through a TRPV1 and autophagy-dependent mechanism. Copyright © 2013. Published by Elsevier Inc.

  7. Raspberry ketone induces brown-like adipocyte formation through suppression of autophagy in adipocytes and adipose tissue.

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    Leu, Sy-Ying; Tsai, Yung-Chieh; Chen, Wen-Chi; Hsu, Chih-Hsiung; Lee, Yen-Mei; Cheng, Pao-Yun

    2018-02-13

    Promoting white adipose tissue (WAT) to acquire brown-like characteristics is a promising approach for obesity treatment. Although raspberry ketone (RK) has been reported to possess antiobesity activity, its effects on the formation of brown-like adipocytes remain unclear. Therefore, we investigated the effects and underlying mechanism of RK on WAT browning in 3T3-L1 adipocytes and rats with ovariectomy (Ovx)-induced obesity. RK (100 μM) significantly induced browning of 3T3-L1 cells by increasing mitochondrial biogenesis and the expression of browning-specific proteins (PR domain containing 16, PRDM16; peroxisome proliferator-activated receptor gamma coactivator 1-alpha, PGC-1α; uncoupling protein-1, UCP-1) and lipolytic enzymes (hormone-sensitive lipase and adipose triglyceride lipase). RK significantly reduced the expression of the autophagy-related protein Atg12 and increased the expression of p62 and heme oxygenase 1 (HO-1). Additionally, these effects of RK were reversed by the HO-1 inhibitor SnPP (20 μM). In addition, RK (160 mg/kg, gavage, for 8 weeks) significantly reduced body weight gain (Ovx+RK, 191.8 ± 4.6 g vs. Ovx, 223.6 ± 5.9; P < .05), food intake, the amount of inguinal adipose tissue (Ovx+RK, 9.05 ± 1.1 g vs Ovx, 12.9 ± 0.92 g; P < .05) and the size of white adipocytes in Ovx rats. Moreover, compared to expression in the Ovx group, the levels of browning-specific proteins were significantly higher and the levels of autophagy-related proteins were significantly lower in the Ovx+RK group. Therefore, this study elucidated the mechanism associated with RK-induced WAT browning and thus provides evidence to support the clinical use of RK for obesity treatment. Copyright © 2018. Published by Elsevier Inc.

  8. Kaempferol alleviates ox-LDL-induced apoptosis by up-regulation of autophagy via inhibiting PI3K/Akt/mTOR pathway in human endothelial cells.

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    Che, Jianbo; Liang, Bing; Zhang, Yuan; Wang, Yi; Tang, Jianyu; Shi, Gongning

    Oxidized low-density lipoprotein (ox-LDL) has been reported to induce apoptosis of endothelial cells (ECs) and contribute to the progression of atherosclerosis. Kaempferol has been shown to possess antiatherosclerotic effect. The aim of the present study was to evaluate the effect of kaempferol on ox-LDL-induced apoptosis of human umbilical vein endothelial cells (HUVECs) and its possible molecular basis. The results showed that kaempferol alleviated ox-LDL-induced apoptosis. Kaempferol increased the ratio of LC3-II/I and beclin-1 level in ox-LDL-induced HUVECs. Moreover, the expression of p-Akt and p-mTOR was down-regulated after treatment with kaempferol in ox-LDL-treated HUVECs, which is similar to the effect of PI3K inhibitor (LY294002) or mTOR inhibitor [rapamycin (RAP)]. Besides, autophagy induced by kaempferol was enhanced by LY294002 or RAP, while kaempferol-induced autophagy was attenuated with insulin treatment, the activator of PI3K/Akt/mTOR pathway. Furthermore, insulin also abated the effect of kaempferol on cell viability and apoptosis in ox-LDL-induced HUVECs. The results indicated that kaempferol alleviated ox-LDL-induced cell apoptosis by up-regulation of autophagy via inhibiting PI3K/Akt/mTOR pathway in human ECs. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Crosstalk of ROS/RNS and autophagy in silibinin-induced apoptosis of MCF-7 human breast cancer cells in vitro

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    Zheng, Nan; Liu, Lu; Liu, Wei-wei; Li, Fei; Hayashi, Toshihiko; Tashiro, Shin-ichi; Onodera, Satoshi; Ikejima, Takashi

    2017-01-01

    Reactive oxygen species (ROS) and reactive nitrogen species (RNS) play important roles in regulating cell survival and death. Silibinin is a natural polyphenolic flavonoid isolated from milk thistle with anti-tumor activities, but it was found to induce cytoprotective ROS/RNS in human breast cancer MCF-7 cells. Furthermore, treatment with silibinin down-regulates ERα expression in MCF-7 cells, and inducing both autophagy and apoptosis. In this study we explored the relationship between ER-associated pathways and RNS/ROS in MCF-7 cells. We also investigated the molecular mechanisms underlying the reciprocal regulation between ROS/RNS levels and autophagy in the death signaling pathways in silibinin-treated MCF-7 cells. Silibinin (100–300 μmol/L) dose-dependently increased ROS/RNS generation in MCF-7 cells (with high expression of ERα and low expression of ERβ) and MDA-MB-231 cells (with low expression of ERα and high expression of ERβ). Scavenging ROS/RNS significantly enhanced silibinin-induced death of MCF-7 cells, but not MDA-MB231 cells. Pharmacological activation or blockade of ERα in MCF-7 cells significantly enhanced or decreased, respectively, silibinin-induced ROS/RNS generation, whereas activation or block of ERβ had no effect. In silibinin-treated MCF-7 cells, exposure to the ROS/RNS donators decreased the autophagic levels, whereas inhibition of autophagy with 3-MA significantly increased ROS/RNS levels. We further showed that increases in ROS/RNS generation, ERα activation or autophagy down-regulation had protective roles in silibinin-treated MCF-7 cells. Under a condition of ERα activation, scavenging ROS/RNS or stimulating autophagy enhanced the cytotoxicity of silibinin. These results demonstrate the existence of two conflicting pathways in silibinin-induced death of MCF-7 cells: one involves the down-regulation of ERα and thereby augmenting the pro-apoptotic autophagy downstream, leading to cell death; the other involves the up

  10. Involvement of Autophagy in Coronavirus Replication

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    Paul Britton

    2012-11-01

    Full Text Available Coronaviruses are single stranded, positive sense RNA viruses, which induce the rearrangement of cellular membranes upon infection of a host cell. This provides the virus with a platform for the assembly of viral replication complexes, improving efficiency of RNA synthesis. The membranes observed in coronavirus infected cells include double membrane vesicles. By nature of their double membrane, these vesicles resemble cellular autophagosomes, generated during the cellular autophagy pathway. In addition, coronavirus infection has been demonstrated to induce autophagy. Here we review current knowledge of coronavirus induced membrane rearrangements and the involvement of autophagy or autophagy protein microtubule associated protein 1B light chain 3 (LC3 in coronavirus replication.

  11. Comparative study of the effects of PM1-induced oxidative stress on autophagy and surfactant protein B and C expressions in lung alveolar type II epithelial MLE-12 cells.

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    Bai, Ru; Guan, Longfei; Zhang, Wei; Xu, Jinxia; Rui, Wei; Zhang, Fang; Ding, Wenjun

    2016-12-01

    There is a strong link between smaller air pollution particles and a range of serious health conditions. Thus, there is a need for understanding the impacts of airborne fine particulate matter (PM) with an aerodynamic diameter of PM1) on lung alveolar epithelial cells. In the present study, mouse lung epithelial type II cell MLE-12 cells were used to examine the intracellular oxidative responses and the surfactant protein expressions after exposure to various concentrations of PM1 collected from an urban site and a steel-factory site (referred as uPM1 and sPM1 hereafter, respectively). Physicochemical characterization of PM1 was performed by using scanning electron microscopy and transmission electron microscopy. Cytotoxicity and autophagy induced by PM1 were assessed by using comprehensive approaches after MLE-12 cells were exposed to different concentrations of PM1 for various times. Expression of surfactant proteins B and C in MLE-12 cells was determined by Western blotting. All of the tested PM1 induced cytotoxicity evidenced by significant decrease of cell viability and increase of lactate dehydrogenase (LDH) release in a time- and concentration-dependent manner in the exposed cells compared with the unexposed cells. A similar pattern of increase of intercellular reactive oxygen species (ROS) generation and decrease of superoxide dismutase (SOD) and catalase (CAT) activities was also observed. PM1-induced autophagy was evidenced by an increase in microtubule-associated protein light chain-3 (LC3) puncta, accumulation of LC3II, and increased levels of beclin1. Data from Western blotting showed significant decrease of surfactant protein B and C expressions. Relatively high concentrations of transition metals, including Fe, Cu and Mn, may be responsible for the higher toxicity of sPM1 compared with uPM1. Moreover, pretreatment with N-acetylcysteine (NAC) or Chelex (a metal chelating agent, which removes a large suite of metals from PM1) prevented the increase of

  12. [The mechanism underlying the effects of tea polyphenol on epirubicin-induced autophagy and apoptosis in T24 bladder cancer cells].

    Science.gov (United States)

    Gu, Wen; Yin, Hubin; Liu, Yan; Gou, Xin

    2017-06-01

    Objective To investigate the mechanism by which epirubicin (EPI) induces autophagy and the mechanism by which tea polyphenol (TP) regulates EPI-induced autophagy and apoptosis in T24 bladder cancer cells. Methods T24 cells weredivided into control group, EPI group, TP group and TP plus EPI group. Eight hours after corresponding treatments in different groups, transmission electron microscopy (TEM) was used to observe the image of autophagosomes. The expressions of autophagy-related protein LC3II and p62 in the cells were detected by Western blotting. Apoptotic cells were evaluated after EPI-treatment for 24 hours by flow cytometry combined with annexin V-FITC/PI staining. Western blotting was performed to determine the levels of cleaved-caspase-3 (c-caspase-3) and cleaved-PARP (c-PARP). LC3II was again tested by Western blotting 8 hours after T24 cells were treated with EPI added with autophagy pathway inhibitor chloroquine and 3-methyladenine, and moreover, the levels of LC3II and p-JNK were detected by Western blotting after T24 cells were treated with EPI combined with TP or the JNK inhibitor SP for 8 hours. Results The amount of autophagosomes and the level of LC3IIin TP plus EPI group were much lower than those in EPI group. SP reduced the level of LC3II induced by EPI. EPI increased p-JNK in a time-dependent manner. TP combined with EPI reduced the activity of JNK pathway. The apoptosis rate and the levels of c-caspase-3 and c-PARP in TP plus EPI group were much higher than those in EPI group. Conclusion TP inhibits autophagy through JNK pathway to enhance EPI-induced apoptosis in T24 bladder cancer cell line.

  13. Isogenic FUS-eGFP iPSC Reporter Lines Enable Quantification of FUS Stress Granule Pathology that Is Rescued by Drugs Inducing Autophagy

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    Lara Marrone

    2018-02-01

    Full Text Available Summary: Perturbations in stress granule (SG dynamics may be at the core of amyotrophic lateral sclerosis (ALS. Since SGs are membraneless compartments, modeling their dynamics in human motor neurons has been challenging, thus hindering the identification of effective therapeutics. Here, we report the generation of isogenic induced pluripotent stem cells carrying wild-type and P525L FUS-eGFP. We demonstrate that FUS-eGFP is recruited into SGs and that P525L profoundly alters their dynamics. With a screening campaign, we demonstrate that PI3K/AKT/mTOR pathway inhibition increases autophagy and ameliorates SG phenotypes linked to P525L FUS by reducing FUS-eGFP recruitment into SGs. Using a Drosophila model of FUS-ALS, we corroborate that induction of autophagy significantly increases survival. Finally, by screening clinically approved drugs for their ability to ameliorate FUS SG phenotypes, we identify a number of brain-penetrant anti-depressants and anti-psychotics that also induce autophagy. These drugs could be repurposed as potential ALS treatments. : Sterneckert and colleagues generate isogenic FUS-eGFP reporter iPSCs that enable the identification of stress granule (SG phenotypes specifically induced by the ALS mutation FUS P525L. Compound screening shows that modulation of the PI3K/AKT/mTOR pathway regulating autophagy ameliorates SG phenotypes. A second screen identifies similarly acting brain-penetrant US FDA-approved drugs that could be repurposed to treat ALS. Keywords: amyotrophic lateral sclerosis, induced pluripotent stem cells, FUS, stress granules, autophagy, gene editing, CRISPR/Cas9n

  14. Alcohol Dehydrogenase Protects against Endoplasmic Reticulum Stress-Induced Myocardial Contractile Dysfunction via Attenuation of Oxidative Stress and Autophagy: Role of PTEN-Akt-mTOR Signaling.

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    Jiaojiao Pang

    Full Text Available The endoplasmic reticulum (ER plays an essential role in ensuring proper folding of the newly synthesized proteins. Aberrant ER homeostasis triggers ER stress and development of cardiovascular diseases. ADH is involved in catalyzing ethanol to acetaldehyde although its role in cardiovascular diseases other than ethanol metabolism still remains elusive. This study was designed to examine the impact of ADH on ER stress-induced cardiac anomalies and underlying mechanisms involved using cardiac-specific overexpression of alcohol dehydrogenase (ADH.ADH and wild-type FVB mice were subjected to the ER stress inducer tunicamycin (1 mg/kg, i.p., for 48 hrs. Myocardial mechanical and intracellular Ca(2+ properties, ER stress, autophagy and associated cell signaling molecules were evaluated.ER stress compromised cardiac contractile function (evidenced as reduced fractional shortening, peak shortening, maximal velocity of shortening/relengthening, prolonged relengthening duration and impaired intracellular Ca(2+ homeostasis, oxidative stress and upregulated autophagy (increased LC3B, Atg5, Atg7 and p62, along with dephosphorylation of PTEN, Akt and mTOR, all of which were attenuated by ADH. In vitro study revealed that ER stress-induced cardiomyocyte anomaly was abrogated by ADH overexpression or autophagy inhibition using 3-MA. Interestingly, the beneficial effect of ADH was obliterated by autophagy induction, inhibition of Akt and mTOR. ER stress also promoted phosphorylation of the stress signaling ERK and JNK, the effect of which was unaffected by ADH transgene.Taken together, these findings suggested that ADH protects against ER stress-induced cardiac anomalies possibly via attenuation of oxidative stress and PTEN/Akt/mTOR pathway-regulated autophagy.

  15. Modulation of pathogen recognition by autophagy

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    Ji Eun eOh

    2012-03-01

    Full Text Available Autophagy is an ancient biological process for maintaining cellular homeostasis by degradation of long-lived cytosolic proteins and organelles. Recent studies demonstrated that autophagy is availed by immune cells to regulate innate immunity. On the one hand, cells exert direct effector function by degrading intracellular pathogens; on the other hand, autophagy modulates pathogen recognition and downstream signaling for innate immune responses. Pathogen recognition via pattern recognition receptors induces autophagy. The function of phagocytic cells is enhanced by recruitment of autophagy-related proteins. Moreover, autophagy acts as a delivery system for viral replication complexes to migrate to the endosomal compartments where virus sensing occurs. In another case, key molecules of the autophagic pathway have been found to negatively regulate immune signaling, thus preventing aberrant activation of cytokine production and consequent immune responses. In this review, we focus on the recent advances in the role of autophagy in pathogen recognition and modulation of innate immune responses.

  16. Dopamine Oxidation and Autophagy

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    Patricia Muñoz

    2012-01-01

    Full Text Available The molecular mechanisms involved in the neurodegenerative process of Parkinson's disease remain unclear. Currently, there is a general agreement that mitochondrial dysfunction, α-synuclein aggregation, oxidative stress, neuroinflammation, and impaired protein degradation are involved in the neurodegeneration of dopaminergic neurons containing neuromelanin in Parkinson's disease. Aminochrome has been proposed to play an essential role in the degeneration of dopaminergic neurons containing neuromelanin by inducing mitochondrial dysfunction, oxidative stress, the formation of neurotoxic α-synuclein protofibrils, and impaired protein degradation. Here, we discuss the relationship between the oxidation of dopamine to aminochrome, the precursor of neuromelanin, autophagy dysfunction in dopaminergic neurons containing neuromelanin, and the role of dopamine oxidation to aminochrome in autophagy dysfunction in dopaminergic neurons. Aminochrome induces the following: (i the formation of α-synuclein protofibrils that inactivate chaperone-mediated autophagy; (ii the formation of adducts with α- and β-tubulin, which induce the aggregation of the microtubules required for the fusion of autophagy vacuoles and lysosomes.

  17. Angiogenesis impairment in diabetes: role of methylglyoxal-induced receptor for advanced glycation endproducts, autophagy and vascular endothelial growth factor receptor 2.

    Directory of Open Access Journals (Sweden)

    Hongtao Liu

    Full Text Available Diabetes impairs physiological angiogenesis by molecular mechanisms that are not fully understood. Methylglyoxal (MGO, a metabolite of glycolysis, is increased in patients with diabetes. This study defined the role of MGO in angiogenesis impairment and tested the mechanism in diabetic animals. Endothelial cells and mouse aortas were subjected to Western blot analysis of vascular endothelial growth factor receptor 2 (VEGFR2 protein levels and angiogenesis evaluation by endothelial cell tube formation/migration and aortic ring assays. Incubation with MGO reduced VEGFR2 protein, but not mRNA, levels in a time and dose dependent manner. Genetic knockdown of the receptor for advanced glycation endproducts (RAGE attenuated the reduction of VEGFR2. Overexpression of Glyoxalase 1, the enzyme that detoxifies MGO, reduced the MGO-protein adducts and prevented VEGFR2 reduction. The VEGFR2 reduction was associated with impaired angiogenesis. Suppression of autophagy either by inhibitors or siRNA, but not of the proteasome and caspase, normalized both the VEGFR2 protein levels and angiogenesis. Conversely, induction of autophagy either by rapamycin or overexpression of LC3 and Beclin-1 reduced VEGFR2 and angiogenesis. MGO increased endothelial LC3B and Beclin-1, markers of autophagy, which were accompanied by an increase of both autophagic flux (LC3 punctae and co-immunoprecipitation of VEGFR2 with LC3. Pharmacological or genetic suppression of peroxynitrite (ONOO(- generation not only blocked the autophagy but also reversed the reduction of VEGFR2 and angiogenesis. Like MGO-treated aortas from normglycemic C57BL/6J mice, aortas from diabetic db/db and Akita mice presented reductions of angiogenesis or VEGFR2. Administration of either autophagy inhibitor ex vivo or superoxide scavenger in vivo abolished the reductions. Taken together, MGO reduces endothelial angiogenesis through RAGE-mediated, ONOO(-dependent and autophagy-induced VEGFR2 degradation, which

  18. Triptolide Inhibited Cytotoxicity of Differentiated PC12 Cells Induced by Amyloid-Beta₂₅₋₃₅ via the Autophagy Pathway.

    Science.gov (United States)

    Xu, Pengjuan; Li, Zhigui; Wang, Hui; Zhang, Xiaochen; Yang, Zhuo

    2015-01-01

    Evidence shows that an abnormal deposition of amyloid beta-peptide25-35 (Aβ25-35) was the primary cause of the pathogenesis of Alzheimer's disease (AD). And the elimination of Aβ25-35 is considered an important target for the treatment of AD. Triptolide (TP), isolated from Tripterygium wilfordii Hook.f. (TWHF), has been shown to possess a broad spectrum of biological profiles, including neurotrophic and neuroprotective effects. In our study investigating the effect and potential mechanism of triptolide on cytotoxicity of differentiated rat pheochromocytoma cell line (the PC12 cell line is often used as a neuronal developmental model) induced by Amyloid-Beta25-35 (Aβ25-35), we used 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) assay, flow cytometry, Western blot, and acridine orange staining to detect whether triptolide could inhibit Aβ25-35-induced cell apoptosis. We focused on the potential role of the autophagy pathway in Aβ25-35-treated differentiated PC12 cells. Our experiments show that cell viability is significantly decreased, and the apoptosis increased in Aβ25-35-treated differentiated PC12 cells. Meanwhile, Aβ25-35 treatment increased the expression of microtubule-associated protein light chain 3 II (LC3 II), which indicates an activation of autophagy. However, triptolide could protect differentiated PC12 cells against Aβ25-35-induced cytotoxicity and attenuate Aβ25-35-induced differentiated PC12 cell apoptosis. Triptolide could also suppress the level of autophagy. In order to assess the effect of autophagy on the protective effects of triptolide in differentiated PC12 cells treated with Aβ25-35, we used 3-Methyladenine (3-MA, an autophagy inhibitor) and rapamycin (an autophagy activator). MTT assay showed that 3-MA elevated cell viability compared with the Aβ25-35-treated group and rapamycin inhibits the protection of triptolide. These results suggest that triptolide will repair the neurological damage in AD caused by

  19. Intermittent fasting preserves beta-cell mass in obesity-induced diabetes via the autophagy-lysosome pathway.

    Science.gov (United States)

    Liu, Haiyan; Javaheri, Ali; Godar, Rebecca J; Murphy, John; Ma, Xiucui; Rohatgi, Nidhi; Mahadevan, Jana; Hyrc, Krzysztof; Saftig, Paul; Marshall, Connie; McDaniel, Michael L; Remedi, Maria S; Razani, Babak; Urano, Fumihiko; Diwan, Abhinav

    2017-01-01

    Obesity-induced diabetes is characterized by hyperglycemia, insulin resistance, and progressive beta cell failure. In islets of mice with obesity-induced diabetes, we observe increased beta cell death and impaired autophagic flux. We hypothesized that intermittent fasting, a clinically sustainable therapeutic strategy, stimulates autophagic flux to ameliorate obesity-induced diabetes. Our data show that despite continued high-fat intake, intermittent fasting restores autophagic flux in islets and improves glucose tolerance by enhancing glucose-stimulated insulin secretion, beta cell survival, and nuclear expression of NEUROG3, a marker of pancreatic regeneration. In contrast, intermittent fasting does not rescue beta-cell death or induce NEUROG3 expression in obese mice with lysosomal dysfunction secondary to deficiency of the lysosomal membrane protein, LAMP2 or haplo-insufficiency of BECN1/Beclin 1, a protein critical for autophagosome formation. Moreover, intermittent fasting is sufficient to provoke beta cell death in nonobese lamp2 null mice, attesting to a critical role for lysosome function in beta cell homeostasis under fasting conditions. Beta cells in intermittently-fasted LAMP2- or BECN1-deficient mice exhibit markers of autophagic failure with accumulation of damaged mitochondria and upregulation of oxidative stress. Thus, intermittent fasting preserves organelle quality via the autophagy-lysosome pathway to enhance beta cell survival and stimulates markers of regeneration in obesity-induced diabetes.

  20. Downregulation of ATG14 by EGR1-MIR152 sensitizes ovarian cancer cells to cisplatin-induced apoptosis by inhibiting cyto-protective autophagy

    Science.gov (United States)

    He, Jun; Yu, Jing-Jie; Xu, Qing; Wang, Lin; Zheng, Jenny Z; Liu, Ling-Zhi; Jiang, Bing-Hua

    2015-01-01

    Cisplatin is commonly used in ovarian cancer treatment by inducing apoptosis in cancer cells as a result of lethal DNA damage. However, the intrinsic and acquired resistance to cisplatin in cancer cells remains a big challenge for improving overall survival. The cyto-protective functions of autophagy in cancer cells have been suggested as a potential mechanism for chemoresistance. Here, we reported MIR152 as a new autophagy-regulating miRNA that plays a role in cisplatin-resistance. We showed that MIR152 expression was dramatically downregulated in the cisplatin-resistant cell lines A2780/CP70, SKOV3/DDP compared with their respective parental cells, and in ovarian cancer tissues associated with cisplatin-resistance. Overexpression of MIR152 sensitized cisplatin-resistant ovarian cancer cells by reducing cisplatin-induced autophagy, enhancing cisplatin-induced apoptosis and inhibition of cell proliferation. A mouse subcutaneous xenograft tumor model using A2780/CP70 cells with overexpressing MIR152 was established and displayed decreased tumor growth in response to cisplatin. We also identified that ATG14 is a functional target of MIR152 in regulating autophagy inhibition. Furthermore, we found that EGR1 (early growth response 1) regulated the MIR152 gene at the transcriptional level. Ectopic expression of EGR1 enhanced efficacy of chemotherapy in A2780/CP70 cells. More importantly, these findings were relevant to clinical cases. Both EGR1 and MIR152 expression levels were significantly lower in ovarian cancer tissues with high levels of ERCC1 (excision repair cross-complementation group 1), a marker for cisplatin-resistance. Collectively, these data provide insights into novel mechanisms for acquired cisplatin-resistance. Activation of EGR1 and MIR152 may be a useful therapeutic strategy to overcome cisplatin-resistance by preventing cyto-protective autophagy in ovarian cancer. PMID:25650716

  1. Characterization of early autophagy signaling by quantitative phosphoproteomics

    DEFF Research Database (Denmark)

    Rigbolt, Kristoffer Tg; Zarei, Mostafa; Sprenger, Adrian

    2014-01-01

    Under conditions of nutrient shortage autophagy is the primary cellular mechanism ensuring availability of substrates for continuous biosynthesis. Subjecting cells to starvation or rapamycin efficiently induces autophagy by inhibiting the MTOR signaling pathway triggering increased autophagic flux...

  2. Autophagy suppresses host adaptive immune responses toward Borrelia burgdorferi

    NARCIS (Netherlands)

    Buffen, Kathrin; Oosting, Marije; Li, Yang; Kanneganti, Thirumala-Devi; Netea, Mihai G.; Joosten, Leo A. B.

    Inhibition of autophagy increases the severity of murine Lyme arthritis and human adaptive immune responses against B. burgdorferi. We have previously demonstrated that inhibition of autophagy increased the Borrelia burgdorferi induced innate cytokine production in vitro, but little is known

  3. Roles of oxidative stress and the ERK1/2, PTEN and p70S6K signaling pathways in arsenite-induced autophagy.

    Science.gov (United States)

    Huang, Ya-Chun; Yu, Hsin-Su; Chai, Chee-Yin

    2015-12-15

    Studies show that arsenite induces oxidative stress and modifies cellular function via phosphorylation of proteins and inhibition of DNA repair enzymes. Autophagy, which has multiple physiological and pathological roles in cellular function, is initiated by oxidative stress and is regulated by the signaling pathways of phosphatidylinositol 3-phosphate kinase (PI3K)/mammalian target of rapamycin (mTOR)/p70S6 kinase (p70S6K) and extracellular signaling-regulated protein kinase 1/2 (ERK1/2) that play important roles in oncogenesis. However, the effects of arsenite-induced oxidative stress on autophagy and on expression of related proteins are not fully understood. This study found that cells treated with sodium arsenite had reduced 8-oxoguanine DNA glycosylase 1 (OGG1) and increased 8-hydroxy-2'-deoxyguanosine (8-OHdG) and activating transcription factor (ATF) 3 in SV-40 immortalized human uroepithelial (SV-HUC-1) cells. Arsenite also increased the number of autophagosomes and increased levels of the autophagy markers Beclin-1 and microtubule-associated protein 1 light chain 3B. Reactive oxygen species scavenger decreased arsenite-induced autophagy in SV-HUC-1 cells. Our previous work showed that arsenite induced phosphorylation of the ERK1/2 signaling pathway. The current study further showed that arsenite decreased phosphatase and tensin homologue (PTEN) levels and increased phospho-p70S6 kinase (p-p70S6K) in SV-HUC-1 cells. However, both kinase inhibitor U0126 and the DNA (cytosine-5-)-methyltransferase 1 (DNMT1) inhibitor 5-aza-deoxycytidine abolished the effect of arsenite on expressions of PTEN and p-p70S6K. These results show that autophagy induced by arsenite exposure is mediated by oxidative stress, which regulates activation of the PTEN, p70S6K and ERK1/2 signaling pathways. Thus, this study clarifies the role of autophagy in arsenite-induced urothelial carcinogenesis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. H2O2 treatment or serum deprivation induces autophagy and apoptosis in naked mole-rat skin fibroblasts by inhibiting the PI3K/Akt signaling pathway.

    Science.gov (United States)

    Zhao, Shanmin; Li, Li; Wang, Shiyong; Yu, Chenlin; Xiao, Bang; Lin, Lifang; Cong, Wei; Cheng, Jishuai; Yang, Wenjing; Sun, Wei; Cui, Shufang

    2016-12-20

    Naked mole-rats (NMR; Heterocephalus glaber) display extreme longevity and resistance to cancer. Here, we examined whether autophagy contributes to the longevity of NMRs by assessing the effects of the PI3K/Akt pathway inhibitor LY294002 and the autophagy inhibitor chloroquine (CQ) on autophagy and apoptosis in NMR skin fibroblasts. Serum starvation, H2O2 treatment, and LY294002 treatment all increased the LC3-II/LC3-I ratio and numbers of double-membraned autophagosomes and autophagic vacuoles, and decreased levels of p70S6K, p-AktSer473, and p-AktThr308. By contrast, CQ treatment decreased p70S6K, AktSer473, and AktThr308 levels. The Bax/Bcl-2 ratio increased after 12 h of exposure to LY294002 or CQ. These data show that inhibiting the Akt pathway promotes autophagy and apoptosis in NMR skin fibroblasts. Furthermore, LY294002 or CQ treatment decreased caspase-3, p53, and HIF1-α levels, suggesting that serum starvation or H2O2 treatment increase autophagy and apoptosis in NMR skin fibroblasts by inhibiting the PI3K/Akt pathway. CQ-induced inhibition of late autophagy stages also prevented Akt activation and induced apoptosis. Finally, the HIF-1α and p53 pathways were involved in serum starvation- or H2O2-induced autophagy in NMR skin fibroblasts.

  5. Protective effects of salicylate on PKA inhibitor (H-89)-induced spatial memory deficit via lessening autophagy and apoptosis in rats.

    Science.gov (United States)

    Azimi, Leila; Kachooeian, Maryam; Khodagholi, Fariba; Yans, Asal; Heysieattalab, Soomaayeh; Vakilzadeh, Gelareh; Vosoughi, Nasim; Sanati, Mehdi; Taghizadeh, Ghorban; Sharifzadeh, Mohammad

    In this study, the effects of salicylate on spatial learning and memory, through its effects on autophagy and apoptosis, were evaluated in the presence of the PKA inhibitor H-89. Adult male Wistar rats were divided into experimental groups as follows: salicylate (30, 50, 100μg/0.5μl/side, intra-hippocampal; 400mg/kg, intra-peritoneal), donepezil (1mg/kg as a positive control for behavioral effects of salicylate), H-89 (1μl/side of 5 or 20μM), H-89 plus salicylate and H-89 plus donepezil. The Morris water maze test was used for evaluation of spatial learning and memory. The levels of different apoptotic and autophagic biomarkers were evaluated using the western blot technique. Salicylate (100μg/0.5μl/side) significantly reduced the escape latency on training days, increased the percentage of time spent in the target quadrant during the probe trial and reversed the inhibitory effects of H-89 during the process of spatial learning and memory. The behavioral efficacy of salicylate was comparable to that of donepezil. In addition, salicylate significantly decreased the levels of apoptotic proteins, Bax and caspase 3, and increased the Bcl2 levels in all groups. Furthermore, the levels of LC3II and Atg7 were decreased by salicylate. Our study revealed that both systemic and direct intra-hippocampal administration of salicylate can facilitate the spatial learning and memory. Additionally, intra-hippocampal administration of salicylate can reduce apoptotic and autophagic proteins. The antioxidant activity of salicylate might lead to increased pCREB via stimulation of signaling pathways, resulting in reduction of H-89-induced apoptosis and autophagy. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. TFE3 Alleviates Hepatic Steatosis through Autophagy-Induced Lipophagy and PGC1α-Mediated Fatty Acid β-Oxidation

    Directory of Open Access Journals (Sweden)

    Jie Xiong

    2016-03-01

    Full Text Available Autophagy flux deficiency is closely related to the development of hepatic steatosis. Transcription factor E3 (TFE3 is reported to be a crucial gene that regulates autophagy flux and lysosome function. Therefore, we investigated the role of TFE3 in a cell model of hepatic steatosis. We constructed L02 hepatocyte lines that stably over-expressed or knocked down the expression of TFE3. Subsequently, the effects of TFE3 on hepatocellular lipid metabolism were determined by autophagy flux assay, lipid oil red O (ORO staining, immunofluorescence staining, and mitochondrial β-oxidation assessment. Finally, we analyzed whether peroxisome proliferative activated receptor gamma coactivator 1α (PGC1α was the potential target gene of TFE3 in the regulation of hepatic steatosis using a chromatin immunoprecipitation (CHIP assay and a luciferase reporter system. We found that overexpression of TFE3 markedly alleviated hepatocellular steatosis. On the contrary, downregulation of TFE3 resulted in an aggravated steatosis. The mechanistic studies revealed that the TFE3-manipulated regulatory effects on hepatocellular steatosis are dependent on autophagy-induced lipophagy and PGC1α-mediated fatty acid β-oxidation because blocking these pathways with an Atg5 small interfering RNA (siRNA or PGC1α siRNA dramatically blunted the TFE3-mediated regulation of steatosis. In conclusion, TFE3 gene provides a novel insight into the treatment of hepatic steatosis and other metabolic disease.

  7. Cannabidiol Post-Treatment Alleviates Rat Epileptic-Related Behaviors and Activates Hippocampal Cell Autophagy Pathway Along with Antioxidant Defense in Chronic Phase of Pilocarpine-Induced Seizure.

    Science.gov (United States)

    Hosseinzadeh, Mahshid; Nikseresht, Sara; Khodagholi, Fariba; Naderi, Nima; Maghsoudi, Nader

    2016-04-01

    Abnormal and sometimes severe behavioral and molecular symptoms are usually observed in epileptic humans and animals. To address this issue, we examined the behavioral and molecular aspects of seizure evoked by pilocarpine. Autophagy can promote both cell survival and death, but there are controversial reports about the neuroprotective or neurodegenerative effects of autophagy in seizure. Cannabidiol has anticonvulsant properties in some animal models when used as a pretreatment. In this study, we investigated alteration of seizure scores, autophagy pathway proteins, and antioxidant status in hippocampal cells during the chronic phase of pilocarpine-induced epilepsy after treatment with cannabidiol. Cannabidiol (100 ng, intracerebroventricular injection) delayed the chronic phase of epilepsy. Single administration of cannabidiol during the chronic phase of seizure significantly diminished seizure scores such as mouth clonus, head nodding, monolateral and bilateral forelimb clonus and increased the activity of catalase enzyme and reduced glutathione content. Such a protective effect in the behavioral scores of epileptic rats was also observed after repeated administrations of cannabidiol at the onset of the silent phase. Moreover, the amount of Atg7, conjugation of Atg5/12, Atg12, and LC3II/LC3I ratio increased significantly in epileptic rats treated with repeated injections of cannabidiol. In short, our results suggest that post-treatment of Cannabidiol could enhance the induction of autophagy pathway and antioxidant defense in the chronic phase of epilepsy, which could be considered as the protective mechanisms of cannabidiol in a temporal lobe epilepsy model.

  8. Moderate calorie restriction to achieve normal weight reverses β-cell dysfunction in diet-induced obese mice: involvement of autophagy.

    Science.gov (United States)

    Gao, Xiuying; Yan, Dien; Zhao, Yinan; Tao, Hong; Zhou, Yingsheng

    2015-01-01

    Severe calorie restriction (CR) is shown to improve or even reverse β-cell dysfunction in patients with obesity and type 2 diabetes mellitus. However, whether mild to moderate CR can reverse β-cell dysfunction induced by obesity and the underlying mechanism remain unclear. Autophagy plays an important role in maintaining mass, architecture and function of β-cells. While the impact of CR on β-cell autophagy is unknown. This study aims to investigate the effects of moderate CR on β-cell function and autophagy activity in diet-induced obese (DIO) mice. DIO C57BL/6 mice were subjected to 3 weeks of switching to normal chow (HF → NC group) or normal chow with 40 % CR (HF → NC CR group). Then hematoxylin-eosin and immunohistochemistry staining were performed to observe β-cell morphology. β-cell function was evaluated by intraperitoneal glucose tolerance test in vivo and static GSIS (glucose-stimulated insulin secretion) in isolated islets. β-cell autophagy activity was determined by transmission electron microscope and western blot. In the HF → NC CR group, CR normalized body weights, completely restored glucose tolerance, early-phase and second-phase insulin secretion, insulin sensitivity, and islet size. CR also normalized insulin content and glucose-stimulated insulin secretion in isolated islets in vitro. Furthermore, β-cell autophagy level was increased in the HF → NC CR group, but AMPK phosphorylation remained unchanged. Although HF → NC mice achieved moderate weight loss and normal glucose tolerance, their insulin secretion was not improved compared with obese control mice, and additionally, β-cell autophagy was not activated in these mice. Moderate (40 %) CR to achieve normal weight reversed β-cell dysfunction and insulin resistance, and restored glucose homeostasis in DIO mice. Furthermore, the up-regulation of β-cell autophagy may play a role in this process, independent of AMPK activation.

  9. Rage induces hepatocellular carcinoma proliferation and sorafenib resistance by modulating autophagy.

    Science.gov (United States)

    Li, Jun; Wu, Peng-Wen; Zhou, Yuan; Dai, Bo; Zhang, Peng-Fei; Zhang, Yu-Hen; Liu, Yang; Shi, Xiao-Lei

    2018-02-14

    The receptor for advanced glycation end products (Rage) is involved in the development of various tumors and acts as an oncogenic protein. Rage is overexpressed in tumors including hepatocellular carcinoma (HCC). However, the molecular mechanism of Rage in HCC progression and sorafenib resistance remains unclear. In this study, enhanced Rage expression is highly associated proliferation and contributes to sorafenib resistance. Rage deficiency contributed to autophagy induction through activating AMPK/mTOR signaling pathway, which is important for sorafenib response. Moreover, the interactions between Rage and Rage ligands such as high mobility group box 1 (HMGB1) and s100a4 positively increased Rage expression. Our data indicate that Rage may be a potential target for therapeutic intervention in HCC and biomarker for sorafenib resistance.

  10. Halofuginone-induced autophagy suppresses the migration and invasion of MCF-7 cells via regulation of STMN1 and p53.

    Science.gov (United States)

    Xia, Xiaojing; Wang, Lei; Zhang, Xiaojian; Wang, Shan; Lei, Lianchen; Cheng, Likun; Xu, Yanzhao; Sun, Yawei; Hang, Bolin; Zhang, Gaiping; Bai, YueYu; Hu, JianHe

    2018-05-01

    Traditional Chinese medicines have been recognized as especially promising anticancer agents in modern anticancer research. Halofuginone (HF), an analog of quinazolinone alkaloid extracted from Dichroa febrifuga, is widely used in traditional medicine. However, whether HF inhibits the growth of breast cancer cells and/or reduces the migration and invasion of MCF-7 human breast cancer cells, as well as the underlying mechanisms in vitro, remains unclear. In this study, we report that an HF extract inhibits the growth of MCF-7 cells and reduces their migration and invasion, an important feature of potential anticancer agents. In addition, HF significantly increases the activation of autophagy, which is closely associated with tumor metastasis. As STMN1 and p53 have been closely implicated in breast cancer progression, we analyzed their expression in the context of HF extract treatment. Western blot analysis showed that HF suppresses STMN1 and p53 expression and activity in an autophagy-dependent manner. Collectively, these data indicate that activation of autophagy reduces expression of STMN1 and p53, and the migration and invasion of cancer cells contributes to the anti-cancer effects of the HF. These findings may provide new insight into breast cancer prevention and therapy. © 2017 Wiley Periodicals, Inc.

  11. Inhibition of autophagy induced by PTEN loss promotes intrinsic breast cancer resistance to trastuzumab therapy.

    Science.gov (United States)

    Ning, Liao; Guo-Chun, Zhang; Sheng-Li, An; Xue-Rui, Li; Kun, Wang; Jian, Zu; Chong-Yang, Ren; Ling-Zhu, Wen; Hai-Tong, Lv

    2016-04-01

    This study aims to explore the effects of the phosphatase and tension homolog (PTEN) expression level on autophagic status and on the resistance of breast cancer to trastuzumab treatment. PTEN and LC3I/II were knocked down with shRNA expression vectors, which were transfected into estrogen receptor (ER)-positive breast cancer cell lines. After trastuzumab treatment, the changes in the autophagy signal transduction pathways and autophagic proteins (LC3I/II, p62, LAMP, and cathepsin B) in these stably transfected cells were detected using western blot. The cells were also orthotopically implanted into nude mice to explore the influence of PTEN knockdown on tumor size, cell viability, and autophagic proteins after trastuzumab treatment. Similar determinations were performed using the LC3I/II overexpressed shPTEN breast cancer cells (LC3I/II-shPTEN). Downregulation of PTEN and autophagic proteins LC3-I and LC3-II was observed in resistant human breast cancer samples. Knockdown of PTEN and PTEN+ LC3I/II with shRNA in breast cancer cells resulted in increased resistance to trastuzumab. Consistently, trastuzumab treatment could not effectively reduce tumor size. Significant decreases in the levels of autophagic proteins LC3I/II, LAMP, p62, cathepsin B, and PI3K-Akt-mTOR and the signaling pathway protein Akt were found in PTEN knockdown cells, compared to the PTEN normal group, after trastuzumab administration, both in vitro and in vivo. However, these findings were reversed with the LC3I/II-shPTEN treatment. Therefore, the loss of PTEN may promote the development of primary resistance to trastuzumab in breast cancer via autophagy defects.

  12. 5-Methoxyflavanone induces cell cycle arrest at the G2/M phase, apoptosis and autophagy in HCT116 human colon cancer cells

    International Nuclear Information System (INIS)

    Shin, Soon Young; Hyun, Jiye; Yu, Jae-Ran; Lim, Yoongho; Lee, Young Han

    2011-01-01

    Natural flavonoids have diverse pharmacological activities, including anti-oxidative, anti-inflammatory, and anti-cancer activities. In this study, we investigated the molecular mechanism underlying the action of 5-methoxyflavanone (5-MF) which has a strong bioavailability and metabolic stability. Our results show that 5-MF inhibited the growth and clonogenicity of HCT116 human colon cancer cells, and that it activated DNA damage responses, as revealed by the accumulation of p53 and the phosphorylation of DNA damage-sensitive proteins, including ataxia-telangiectasia mutated (ATM) at Ser1981, checkpoint kinase 2 (Chk2) at Thr68, and histone H2AX at Ser139. 5-MF-induced DNA damage was confirmed in a comet tail assay. We also found that 5-MF increased the cleavage of caspase-2 and -7, leading to the induction of apoptosis. Pretreatment with the ATM inhibitor KU55933 enhanced 5-MF-induced γ-H2AX formation and caspase-7 cleavage. HCT116 cells lacking p53 (p53 -/- ) or p21 (p21 -/- ) exhibited increased sensitivity to 5-MF compared to wild-type cells. 5-MF further induced autophagy via an ERK signaling pathway. Blockage of autophagy with the MEK inhibitor U0126 potentiated 5-MF-induced γ-H2AX formation and caspase-2 activation. These results suggest that a caspase-2 cascade mediates 5-MF-induced anti-tumor activity, while an ATM/Chk2/p53/p21 checkpoint pathway and ERK-mediated autophagy act as a survival program to block caspase-2-mediated apoptosis induced by 5-MF. - Graphical abstract: Display Omitted Highlights: → 5-MF inhibits the proliferation of HCT116 colon cancer cells. → 5-MF inhibits cell cycle progression and induces apoptosis. → Inhibition of autophagy triggers 5-MF-induced apoptosis. → Inhibition of ERK signaling blocks 5-MF-induced autophagy but activates apoptosis. → Treatment with 5-MF in combination with an ERK inhibitor may be a potential therapeutic strategy in human colon cancer.

  13. Heat-modified citrus pectin induces apoptosis-like cell death and autophagy in HepG2 and A549 cancer cells.

    Directory of Open Access Journals (Sweden)

    Lionel Leclere

    Full Text Available Cancer is still one of the leading causes of death worldwide, and finding new treatments remains a major challenge. Previous studies showed that modified forms of pectin, a complex polysaccharide present in the primary plant cell wall, possess anticancer properties. Nevertheless, the mechanism of action of modified pectin and the pathways involved are unclear. Here, we show that citrus pectin modified by heat treatment induced cell death in HepG2 and A549 cells. The induced cell death differs from classical apoptosis because no DNA cleavage was observed. In addition, Z-VAD-fmk, a pan-caspase inhibitor, did not influence the observed cell death in HepG2 cells but appeared to be partly protective in A549 cells, indicating that heat-modified citrus pectin might induce caspase-independent cell death. An increase in the abundance of the phosphatidylethanolamine-conjugated Light Chain 3 (LC3 protein and a decrease in p62 protein abundance were observed in both cell types when incubated in the presence of heat-modified citrus pectin. These results indicate the activation of autophagy. To our knowledge, this is the first time that autophagy has been revealed in cells incubated in the presence of a modified form of pectin. This autophagy activation appears to be protective, at least for A549 cells, because its inhibition with 3-methyladenine increased the observed modified pectin-induced cytotoxicity. This study confirms the potential of modified pectin to improve chemotherapeutic cancer treatments.

  14. Heat-modified citrus pectin induces apoptosis-like cell death and autophagy in HepG2 and A549 cancer cells.

    Science.gov (United States)

    Leclere, Lionel; Fransolet, Maude; Cote, Francois; Cambier, Pierre; Arnould, Thierry; Van Cutsem, Pierre; Michiels, Carine

    2015-01-01

    Cancer is still one of the leading causes of death worldwide, and finding new treatments remains a major challenge. Previous studies showed that modified forms of pectin, a complex polysaccharide present in the primary plant cell wall, possess anticancer properties. Nevertheless, the mechanism of action of modified pectin and the pathways involved are unclear. Here, we show that citrus pectin modified by heat treatment induced cell death in HepG2 and A549 cells. The induced cell death differs from classical apoptosis because no DNA cleavage was observed. In addition, Z-VAD-fmk, a pan-caspase inhibitor, did not influence the observed cell death in HepG2 cells but appeared to be partly protective in A549 cells, indicating that heat-modified citrus pectin might induce caspase-independent cell death. An increase in the abundance of the phosphatidylethanolamine-conjugated Light Chain 3 (LC3) protein and a decrease in p62 protein abundance were observed in both cell types when incubated in the presence of heat-modified citrus pectin. These results indicate the activation of autophagy. To our knowledge, this is the first time that autophagy has been revealed in cells incubated in the presence of a modified form of pectin. This autophagy activation appears to be protective, at least for A549 cells, because its inhibition with 3-methyladenine increased the observed modified pectin-induced cytotoxicity. This study confirms the potential of modified pectin to improve chemotherapeutic cancer treatments.

  15. Autophagy in DNA Damage Response

    Directory of Open Access Journals (Sweden)

    Piotr Czarny

    2015-01-01

    Full Text Available DNA damage response (DDR involves DNA repair, cell cycle regulation and apoptosis, but autophagy is also suggested to play a role in DDR. Autophagy can be activated in response to DNA-damaging agents, but the exact mechanism underlying this activation is not fully understood, although it is suggested that it involves the inhibition of mammalian target of rapamycin complex 1 (mTORC1. mTORC1 represses autophagy via phosphorylation of the ULK1/2–Atg13–FIP200 complex thus preventing maturation of pre-autophagosomal structures. When DNA damage occurs, it is recognized by some proteins or their complexes, such as poly(ADPribose polymerase 1 (PARP-1, Mre11–Rad50–Nbs1 (MRN complex or FOXO3, which activate repressors of mTORC1. SQSTM1/p62 is one of the proteins whose levels are regulated via autophagic degradation. Inhibition of autophagy by knockout of FIP200 results in upregulation of SQSTM1/p62, enhanced DNA damage and less efficient damage repair. Mitophagy, one form of autophagy involved in the selective degradation of mitochondria, may also play role in DDR. It degrades abnormal mitochondria and can either repress or activate apoptosis, but the exact mechanism remains unknown. There is a need to clarify the role of autophagy in DDR, as this process may possess several important biomedical applications, involving also cancer therapy.

  16. Autophagy, signaling and obesity

    NARCIS (Netherlands)

    Lavallard, Vanessa J.; Meijer, Alfred J.; Codogno, Patrice; Gual, Philippe

    2012-01-01

    Autophagy is a cellular pathway crucial for development, differentiation, survival and homeostasis. Autophagy can provide protection against aging and a number of pathologies such as cancer, neurodegeneration, cardiac disease and infection. Recent studies have reported new functions of autophagy in

  17. Nucleotropic doxorubicin nanoparticles decrease cancer cell viability, destroy mitochondria, induce autophagy and enhance tumour necrosis.

    Science.gov (United States)

    Friedhuber, Anna M; Chandolu, Vijay; Manchun, Somkamon; Donkor, Osaana; Sriamornsak, Pornsak; Dass, Crispin R

    2015-01-01

    Doxorubicin (Dox) is used clinically against various neoplasias, but suffers from serious side effects, and for the past three decades, this shortcoming has spurred research towards finding better drug delivery systems (DDSs) for this frontline drug. A non-targeted nucleotropic Dox-loaded nanoparticle (DNP) DDS is described, which has a simple chemical design, is easy to formulate and administer, is inexpensive, non-biohazardous and may prove to be useful clinically. The DNP formulated via vortex-assisted complex coarcevation enhanced (300-fold) cell-inhibitory activity of the drug in a panel of human cancer cells (osteosarcoma, breast, prostate and colorectal cancer) and enhanced (10-fold) efficacy against osteosarcoma (OS) in vivo. The slow-release DNPs localised to the endoplasmic reticulum disrupted the mitochondria and entered the nucleus. Prominent cytosolic vacuolisation, budding off of portions of the cytoplasm, both suggestive of autophagy, were observed. Mice that were administered with DNPs intratumorally had the smallest tumours at the end of the study, with more necrotic hotspots. This promising nucleotropic DDS enhances the cell delivery and activity of Dox against a variety of human cancer cell lines and in OS tumours in mice. © 2014 Royal Pharmaceutical Society.

  18. Obestatin controls the ubiquitin-proteasome and autophagy-lysosome systems in glucocorticoid-induced muscle cell atrophy.

    Science.gov (United States)

    Cid-Díaz, Tania; Santos-Zas, Icía; González-Sánchez, Jessica; Gurriarán-Rodríguez, Uxía; Mosteiro, Carlos S; Casabiell, Xesús; García-Caballero, Tomás; Mouly, Vincent; Pazos, Yolanda; Camiña, Jesús P

    2017-12-01

    Many pathological states characterized by muscle atrophy are associated with an increase in circulating glucocorticoids and poor patient prognosis, making it an important target for treatment. The development of treatments for glucocorticoid-induced and wasting disorder-related skeletal muscle atrophy should be designed based on how the particular transcriptional program is orchestrated and how the balance of muscle protein synthesis and degradation is deregulated. Here, we investigated whether the obestatin/GPR39 system, an autocrine/paracrine signaling system acting on myogenesis and with anabolic effects on the skeletal muscle, could protect against glucocorticoid-induced muscle cell atrophy. In the present study, we have utilized mouse C2C12 myotube cultures to examine whether the obestatin/GPR39 signaling pathways can affect the atrophy induced by the synthetic glucocorticoid dexamethasone. We have extended these findings to in vitro effects on human atrophy using human KM155C25 myotubes. The activation of the obestatin/GPR39 system protects from glucocorticoid-induced atrophy by regulation of Akt, PKD/PKCμ, CAMKII and AMPK signaling and its downstream targets in the control of protein synthesis, ubiquitin-proteasome system and autophagy-lysosome system in mouse cells. We compared mouse and human myotube cells in their response to glucocorticoid and identified differences in both the triggering of the atrophic program and the response to obestatin stimulation. Notably, we demonstrate that specific patterns of post-translational modifications of FoxO4 and FoxO1 play a key role in directing FoxO activity in response to obestatin in human myotubes. Our findings emphasize the function of the obestatin/GPR39 system in coordinating a variety of pathways involved in the regulation of protein degradation during catabolic conditions. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on

  19. Emerging role of mammalian autophagy in ketogenesis to overcome starvation

    OpenAIRE

    Takagi, Ayano; Kume, Shinji; Maegawa, Hiroshi; Uzu, Takashi

    2016-01-01

    Autophagy is essential for the survival of lower organisms under conditions of nutrient depletion. However, whether autophagy plays a physiological role in mammals experiencing starvation is unknown. Ketogenesis is critical for overcoming starvation in mammals. We recently revealed that hepatic and renal autophagy are involved in starvation-induced ketogenesis, by utilizing tissue-specific autophagy-deficient mouse models. The liver is the principal organ to regulate ketogenesis, and a defici...

  20. rBTI reduced β-amyloid-induced toxicity by promoting autophagy-lysosomal degradation via DAF-16 in Caenorhabditis elegans.

    Science.gov (United States)

    Li, Jiao; Cui, Xiaodong; Ma, Xiaoli; Wang, Zhuanhua

    2017-03-01

    Alzheimer's disease (AD) is an age-related neurodegenerative disease, of which β-amyloid (Aβ) induced toxicity was suggested as a main cause. Some substances with prolongevity effects have been shown to be protective against AD. In a previous study we demonstrated that a recombinant buckwheat trypsin inhibitor (rBTI) could prolonge the lifespan in Caenorhabditis elegans (C. elegans). Here, we investigated whether rBTI may benefit to mitigate the AD symptom by feeding the AD model C. elegans CL4176. CL4176 is a transgenic C. elegans expressing human Aβ 3-42 in muscle tissue. The results showed that rBTI not only could extend lifespan but also could reduce Aβ toxicity-triggered body paralysis in AD worms. Further study found the accumulation of Aβ was decreased and autophagy-lysosomal degradation pathway was activated in AD worms treated with rBTI. Moreover, the inhibition of autophagy reduced rBTI-mediated paralysis delay. Genetic analyses showed rBTI increased the transcriptional activity of dauer formation abnormal-16 (DAF-16) and the disruption of daf-16 abolished rBTI-mediated protective effect in AD worms. Taken together, these data indicated that rBTI promoted the autophagy-lysosomal degradation pathway to reduce the Aβ-induced toxicity via DAF-16 in an AD model C. elegans, implying that BTI has the potential to protect against AD. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Reduction of STAT3 expression induces mitochondrial dysfunction and autophagy in cardiac HL-1 cells.

    Science.gov (United States)

    Elschami, Myriam; Scherr, Michaela; Philippens, Brigitte; Gerardy-Schahn, Rita

    2013-01-01

    Signal transducer and activator of transcription 3 (STAT3) is an important mediator of cardiac survival pathways. Reduced levels of STAT3 in patients with end-stage heart failure suggest a clinical relevance of STAT3 deficiency for cardiac disease. The recent identification of STAT3 as a mitochondrial protein which is important for full activity of mitochondrial complex I has opened a new field for the investigation of how STAT3 functions in cardioprotection. The goal of this study was to establish a cell culture model with a reduced STAT3 expression, and to use this model for the investigation of mitochondrial and mitochondrial-associated functions under STAT3 deficiency. In the murine cardiomyogenic cell line HL-1, the expression of STAT3 was silenced by lentiviral transduction with anti-STAT3 shRNA (STAT3 KD cells). STAT3 mRNA and protein levels were significantly reduced in HL-1 STAT3 KD cells compared to HL-1 cells transduced with a control shRNA. Spectrophotometric and polarographic assays with mitochondrial enriched fractions and intact cells showed reduced activities of respiratory chain complexes I, II, III and IV in HL-1 STAT3 KD cells. At ultrastructural level, a severe damage of mitochondrial integrity was observed, combined with a significant increase in autophagolysosomes in STAT3-deficient HL-1 cells. Our results demonstrate that the HL-1 STAT3 KD cell line is a good model to study cellular consequences of STAT3 deficiency. Moreover, this is the first study to show that STAT3 deficiency leads to a disruption of mitochondrial ultrastructure and increased autophagy. Copyright © 2012 Elsevier GmbH. All rights reserved.

  2. Melatonin Reverses Fas, E2F-1 and Endoplasmic Reticulum Stress Mediated Apoptosis and Dysregulation of Autophagy Induced by the Herbicide Atrazine in Murine Splenocytes.

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    Shweta Sharma

    Full Text Available Exposure to the herbicide Atrazine (ATR can cause immunotoxicity, apart from other adverse consequences for animal and human health. We aimed at elucidating the apoptotic mechanisms involved in immunotoxicity of ATR and their attenuation by Melatonin (MEL. Young Swiss mice were divided into control, ATR and MEL+ATR groups based on daily (x14 intraperitoneal administration of the vehicle (normal saline, ATR (100 mg/kg body weight and MEL (20 mg/kg body weight with ATR. Isolated splenocytes were processed for detection of apoptosis by Annexin V-FITC and TUNEL assays, and endoplasmic reticulum (ER stress by immunostaining. Key proteins involved in apoptosis, ER stress and autophagy were quantified by immunoblotting. ATR treatment resulted in Fas-mediated activation of caspases 8 and 3 and inactivation of PARP1 which were inhibited significantly by co-treatment with MEL. MEL also attenuated the ATR-induced, p53 independent mitochondrial apoptosis through upregulation of E2F-1 and PUMA and suppression of their downstream target Bax. An excessive ER stress triggered by ATR through overexpression of ATF-6α, spliced XBP-1, CREB-2 and GADD153 signals was reversed by MEL. MEL also reversed the ATR-induced impairment of autophagy which was indicated by a decline in BECN-1, along with significant enhancement in LC3B-II and p62 expressions. Induction of mitochondrial apoptosis, ER stress and autophagy dysregulation provide a new insight into the mechanism of ATR immunotoxicity. The cytoprotective role of MEL, on the other hand, was defined by attenuation of ER stress, Fas-mediated and p53 independent mitochondria-mediated apoptosis as well as autophagy signals.

  3. A tail-anchored myotonic dystrophy protein kinase isoform induces perinuclear clustering of mitochondria, autophagy, and apoptosis.

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    Ralph J A Oude Ophuis

    Full Text Available BACKGROUND: Studies on the myotonic dystrophy protein kinase (DMPK gene and gene products have thus far mainly concentrated on the fate of length mutation in the (CTGn repeat at the DNA level and consequences of repeat expansion at the RNA level in DM1 patients and disease models. Surprisingly little is known about the function of DMPK protein products. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrate here that transient expression of one major protein product of the human gene, the hDMPK A isoform with a long tail anchor, results in mitochondrial fragmentation and clustering in the perinuclear region. Clustering occurred in a variety of cell types and was enhanced by an intact tubulin cytoskeleton. In addition to morphomechanical changes, hDMPK A expression induces physiological changes like loss of mitochondrial membrane potential, increased autophagy activity, and leakage of cytochrome c from the mitochondrial intermembrane space accompanied by apoptosis. Truncation analysis using YFP-hDMPK A fusion constructs revealed that the protein's tail domain was necessary and sufficient to evoke mitochondrial clustering behavior. CONCLUSION/SIGNIFICANCE: Our data suggest that the expression level of the DMPK A isoform needs to be tightly controlled in cells where the hDMPK gene is expressed. We speculate that aberrant splice isoform expression might be a codetermining factor in manifestation of specific DM1 features in patients.

  4. Emerging role of mammalian autophagy in ketogenesis to overcome starvation.

    Science.gov (United States)

    Takagi, Ayano; Kume, Shinji; Maegawa, Hiroshi; Uzu, Takashi

    2016-01-01

    Autophagy is essential for the survival of lower organisms under conditions of nutrient depletion. However, whether autophagy plays a physiological role in mammals experiencing starvation is unknown. Ketogenesis is critical for overcoming starvation in mammals. We recently revealed that hepatic and renal autophagy are involved in starvation-induced ketogenesis, by utilizing tissue-specific autophagy-deficient mouse models. The liver is the principal organ to regulate ketogenesis, and a deficiency of liver-specific autophagy partially but significantly attenuates starvation-induced ketogenesis. While deficiency of renal-specific autophagy does not affect starvation-induced ketogenesis, mice with deficiency of both liver and kidney autophagy have even lower blood ketone levels and physical activity under starvation conditions than those lacking autophagy in the liver alone. These results suggest that the kidney can compensate for impaired hepatic ketogenesis. Since ketone bodies are catabolized from fatty acids, the uptake of fatty acids, the formation of intracellular lipid droplets, and fatty acid oxidation are critical for ketogenesis. We found that starvation-induced lipid droplet formation is impaired in autophagy-deficient organs. Thus, hepatic and renal autophagy are required for starvation-induced ketogenesis. This process is essential for maintaining systemic energy homeostasis and physical activity during starvation. Our findings provide a novel insight into mammalian autophagy and the physiology of starvation.

  5. Autophagy Proteins in Phagocyte Endocytosis and Exocytosis

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    Christian Münz

    2017-09-01

    Full Text Available Autophagy was initially described as a catabolic pathway that recycles nutrients of cytoplasmic constituents after lysosomal degradation during starvation. Since the immune system monitors products of lysosomal degradation via major histocompatibility complex (MHC class II restricted antigen presentation, autophagy was found to process intracellular antigens for display on MHC class II molecules. In recent years, however, it has become apparent that the molecular machinery of autophagy serves phagocytes in many more membrane trafficking pathways, thereby regulating immunity to infectious disease agents. In this minireview, we will summarize the recent evidence that autophagy proteins regulate phagocyte endocytosis and exocytosis for myeloid cell activation, pathogen replication, and MHC class I and II restricted antigen presentation. Selective stimulation and inhibition of the respective functional modules of the autophagy machinery might constitute valid therapeutic options in the discussed disease settings.

  6. Approaches for Studying Autophagy in Caenorhabditis elegans

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    Yanfang Chen

    2017-08-01

    Full Text Available Macroautophagy (hereafter referred to as autophagy is an intracellular degradative process, well conserved among eukaryotes. By engulfing cytoplasmic constituents into the autophagosome for degradation, this process is involved in the maintenance of cellular homeostasis. Autophagy induction triggers the formation of a cup-shaped double membrane structure, the phagophore, which progressively elongates and encloses materials to be removed. This double membrane vesicle, which is called an autophagosome, fuses with lysosome and forms the autolysosome. The inner membrane of the autophagosome, along with engulfed compounds, are degraded by lysosomal enzymes, which enables the recycling of carbohydrates, amino acids, nucleotides, and lipids. In response to various factors, autophagy can be induced for non-selective degradation of bulk cytoplasm. Autophagy is also able to selectively target cargoes and organelles such as mitochondria or peroxisome, functioning as a quality control system. The modification of autophagy flux is involved in developmental processes such as resistance to stress conditions, aging, cell death, and multiple pathologies. So, the use of animal models is essential for understanding these processes in the context of different cell types throughout the entire lifespan. For almost 15 years, the nematode Caenorhabditis elegans has emerged as a powerful model to analyze autophagy in physiological or pathological contexts. This review presents a rapid overview of physiological processes involving autophagy in Caenorhabditis elegans, the different assays used to monitor autophagy, their drawbacks, and specific tools for the analyses of selective autophagy.

  7. Autophagy and the nutritional signaling pathway

    Directory of Open Access Journals (Sweden)

    Long HE,Shabnam ESLAMFAM,Xi MA,Defa LI

    2016-09-01

    Full Text Available During their growth and development, animals adapt to tremendous changes in order to survive. These include responses to both environmental and physiological changes and autophagy is one of most important adaptive and regulatory mechanisms. Autophagy is defined as an autolytic process to clear damaged cellular organelles and recycle the nutrients via lysosomic degradation. The process of autophagy responds to special conditions such as nutrient withdrawal. Once autophagy is induced, phagophores form and then elongate and curve to form autophagosomes. Autophagosomes then engulf cargo, fuse with endosomes, and finally fuse with lysosomes for maturation. During the initiation process, the ATG1/ULK1 (unc-51-like kinase 1 and VPS34 (which encodes a class III phosphatidylinositol (PtdIns 3-kinase complexes are critical in recruitment and assembly of other complexes required for autophagy. The process of autophagy is regulated by autophagy related genes (ATGs. Amino acid and energy starvation mediate autophagy by activating mTORC1 (mammalian target of rapamycin and AMP-activated protein kinase (AMPK. AMPK is the energy status sensor, the core nutrient signaling component and the metabolic kinase of cells. This review mainly focuses on the mechanism of autophagy regulated by nutrient signaling especially for the two important complexes, ULK1 and VPS34.

  8. Longevity-relevant regulation of autophagy at the level of the acetylproteome

    DEFF Research Database (Denmark)

    Mariño, Guillermo; Morselli, Eugenia; Bennetzen, Martin V

    2011-01-01

    , spermidine and resveratrol frequently affect the acetylation pattern in a similar fashion. In the cytoplasm, spermidine and resveratrol induce convergent protein de-acetylation more frequently than convergent acetylation, while in the nucleus, acetylation is dominantly triggered by both agents. We surmise......The acetylase inhibitor, spermidine and the deacetylase activator, resveratrol, both induce autophagy and prolong life span of the model organism Caenorhabditis elegans in an autophagydependent fashion. Based on these premises, we investigated the differences and similarities in spermidine...

  9. Molecular Interactions of Autophagy with the Immune System and Cancer

    Directory of Open Access Journals (Sweden)

    Yunho Jin

    2017-08-01

    Full Text Available Autophagy is a highly conserved catabolic mechanism that mediates the degradation of damaged cellular components by inducing their fusion with lysosomes. This process provides cells with an alternative source of energy for the synthesis of new proteins and the maintenance of metabolic homeostasis in stressful environments. Autophagy protects against cancer by mediating both innate and adaptive immune responses. Innate immune receptors and lymphocytes (T and B are modulated by autophagy, which represent innate and adaptive immune responses, respectively. Numerous studies have demonstrated beneficial roles for autophagy induction as well as its suppression of cancer cells. Autophagy may induce either survival or death depending on the cell/tissue type. Radiation therapy is commonly used to treat cancer by inducing autophagy in human cancer cell lines. Additionally, melatonin appears to affect cancer cell death by regulating programmed cell death. In this review, we summarize the current understanding of autophagy and its regulation in cancer.

  10. 14-Deoxy-11,12-didehydroandrographolide induces DDIT3-dependent endoplasmic reticulum stress-mediated autophagy in T-47D breast carcinoma cells

    International Nuclear Information System (INIS)

    Tan, Heng Kean; Muhammad, Tengku Sifzizul Tengku; Tan, Mei Lan

    2016-01-01

    14-Deoxy-11,12-didehydroandrographolide (14-DDA), a major diterpenoid isolated from Andrographis paniculata (Burm.f.) Nees, is known to be cytotoxic and elicits a non-apoptotic cell death in T-47D breast carcinoma cells. In this study, the mechanistic toxicology properties of 14-DDA in T-47D cells were further investigated. 14-DDA is found to induce the formation of endoplasmic reticulum (ER) vacuoles and autophagosomes, with concurrent upregulation of LC3-II in the breast carcinoma cells. It stimulated an increase in cytosolic calcium concentration and caused a collapse in mitochondrial membrane potential in these cells. In addition, both DDIT3 and GADD45A, molecules implicated in ER stress pathway, were significantly upregulated. DDIT3 knockdown suppressed the formation of both ER vacuoles and autophagosomes, indicating that 14-DDA-induced ER stress and autophagy is dependent on this transcription factor. Collectively, it is possible that GADD45A/p38 MAPK/DDIT3 pathway is involved in the 14-DDA-induced ER-stress-mediated autophagy in T-47D cells. - Highlights: • The mechanistic toxicology properties of 14-DDA in T-47D breast carcinoma cells were investigated. • 14-DDA induces the formation of ER vacuoles and autophagosomes, with concurrent upregulation of LC3-II. • It stimulates an increase in cytosolic calcium concentration and causing collapse in the mitochondrial membrane potential. • Both DDIT3 and GADD45A, molecules implicated in ER stress pathway, were significantly upregulated. • 4-DDA induces ER stress-mediated autophagy in T-47D cells possibly via GADD45A/p38 MAPK/DDIT3 pathway.

  11. Picornavirus Subversion of the Autophagy Pathway

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    William T. Jackson

    2011-08-01

    Full Text Available While autophagy has been shown to act as an anti-viral defense, the Picornaviridae avoid and, in many cases, subvert this pathway to promote their own replication. Evidence indicates that some picornaviruses hijack autophagy in order to induce autophagosome-like membrane structures for genomic RNA replication. Expression of picornavirus proteins can specifically induce the machinery of autophagy, although the mechanisms by which the viruses employ autophagy appear to differ. Many picornaviruses up-regulate autophagy in order to promote viral replication while some members of the family also inhibit degradation by autolysosomes. Here we explore the unusual relationship of this medically important family of viruses with a degradative mechanism of innate immunity.

  12. Picornavirus subversion of the autophagy pathway.

    Science.gov (United States)

    Klein, Kathryn A; Jackson, William T

    2011-09-01

    While autophagy has been shown to act as an anti-viral defense, the Picornaviridae avoid and, in many cases, subvert this pathway to promote their own replication. Evidence indicates that some picornaviruses hijack autophagy in order to induce autophagosome-like membrane structures for genomic RNA replication. Expression of picornavirus proteins can specifically induce the machinery of autophagy, although the mechanisms by which the viruses employ autophagy appear to differ. Many picornaviruses up-regulate autophagy in order to promote viral replication while some members of the family also inhibit degradation by autolysosomes. Here we explore the unusual relationship of this medically important family of viruses with a degradative mechanism of innate immunity.

  13. Herbal extract of Artemisia vulgaris (mugwort) induces antitumor effects in HCT-15 human colon cancer cells via autophagy induction, cell migration suppression and loss of mitochondrial membrane potential.

    Science.gov (United States)

    Lian, Guanghui; Li, Fujun; Yin, Yani; Chen, Linlin; Yang, Junwen

    2018-01-01

    Artemisia vulgaris (A.vulgaris) belonging to family Compositae, commonly known as mugwort, has been used as a medicinal herb in Chinese traditional medicine for treatment of diseases. Studies have reported a diversity of activities for this plant which include antiseptic, antispasmodic, antigastric, anticancer and nervous system diseases. However, the anticancer activity of A.vulgaris in HCT-15 human colon cancer cells has not been scientifically validated. Therefore the present study aimed at evaluating the anticancer activity of methanolic extract of A.vulgaris against HCT-15 human colon cancer cell line. Cell cytotoxicity effects of the extract were evaluated by MTT cell viability assay, while clonogenic assay assessed the effects on cancer cell colony formation. Effects on reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP) were evaluated by flow cytometry. In vitro wound healing assay was used to evaluate the effects on cell migration. To confirm autophagy, we evaluated the expression of several autophagy-associated proteins using Western blot assay. Results indicated that the methanolic extract of A.vulgaris exhibited an IC50 value of 50 μg/ml and exerted its cytotoxic effects in a dose-dependent manner. Moreover, it was observed that the extract inhibits colony formation and induces autophagy dose-dependently. The underlying mechanism for the induction of autophagy was found to be ROS-mediated MMP and significant inhibition of cell migration potential of colon cancer cells at the IC50 was observed. These results strongly stress that the methanolic extract may prove a source for the isolation of novel anticancer lead molecules for the management of colon cancer.

  14. Concurrent Autophagy Inhibition Overcomes the Resistance of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Human Bladder Cancer Cells

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    Minyong Kang

    2017-02-01

    Full Text Available Despite the potential therapeutic efficacy of epithelial growth factor receptor (EGFR inhibitors in the treatment of advanced stage bladder cancer, there currently is no clear evidence to support this hypothesis. In this study, we investigate whether the concurrent treatment of autophagy-blocking agents with EGFR inhibitors exerts synergistic anti-cancer effects in T24 and J82 human bladder cancer cells. Lapatinib and gefitinib were used as EGFR inhibitors, and bafilomycin A1 (BFA1, chloroquine (CQ and 3-methyladenine (3-MA were used as the pharmacologic inhibitors of autophagy activities. To assess the proliferative and self-renewal capabilities, the Cell Counting Kit-8 (CCK-8 assay and a clonogenic assay were performed, respectively. To examine apoptotic cell death, flow cytometry using annexin-V/propidium iodide (PI was used. To measure the autophagy activities, the expression levels of LC3I and II was determined by Western blot analysis. To validate the synergistic effects of autophagy inhibition with EGFR inhibitors, we specifically blocked key autophagy regulatory gene ATG12 by transfection of small interference RNA and examined the phenotypic changes. Of note, lapatinib and gefitinib triggered autophagy activities in T24 and J82 human bladder cancer cells, as indicated by upregulation of LC3II. More importantly, inhibiting autophagy activities with pharmacologic inhibitors (BFA1, CQ or 3-MA remarkably reduced the cell viabilities and clonal proliferation of T24 and J82 cells, compared to those treated with either of the agents alone. We also obtained similar results of the enhanced anti-cancer effects of EGFR inhibitors by suppressing the expression of ATG12. Notably, the apoptotic assay showed that synergistic anti-cancer effects were induced via the increase of apoptotic cell death. In summary, concomitant inhibition of autophagy activities potentiated the anti-cancer effects of EGFR inhibitors in human bladder cancer cells, indicating

  15. Carbamazepine suppresses calpain-mediated autophagy impairment after ischemia/reperfusion in mouse livers

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae-Sung, E-mail: Jae.Kim@surgery.ufl.edu; Wang, Jin-Hee, E-mail: jin-hee.wang@surgery.ufl.edu; Biel, Thomas G., E-mail: Thomas.Biel@surgery.ufl.edu; Kim, Do-Sung, E-mail: do-sung.kim@surgery.med.ufl.edu; Flores-Toro, Joseph A., E-mail: Joseph.Flores-Toro@surgery.ufl.edu; Vijayvargiya, Richa, E-mail: rvijayvargiya@ufl.edu; Zendejas, Ivan, E-mail: ivan.zendejas@surgery.ufl.edu; Behrns, Kevin E., E-mail: Kevin.Behrns@surgery.ufl.edu

    2013-12-15

    Onset of the mitochondrial permeability transition (MPT) plays a causative role in ischemia/reperfusion (I/R) injury. Current therapeutic strategies for reducing reperfusion injury remain disappointing. Autophagy is a lysosome-mediated, catabolic process that timely eliminates abnormal or damaged cellular constituents and organelles such as dysfunctional mitochondria. I/R induces calcium overloading and calpain activation, leading to degradation of key autophagy-related proteins (Atg). Carbamazepine (CBZ), an FDA-approved anticonvulsant drug, has recently been reported to increase autophagy. We investigated the effects of CBZ on hepatic I/R injury. Hepatocytes and livers from male C57BL/6 mice were subjected to simulated in vitro, as well as in vivo I/R, respectively. Cell death, intracellular calcium, calpain activity, changes in autophagy-related proteins (Atg), autophagic flux, MPT and mitochondrial membrane potential after I/R were analyzed in the presence and absence of 20 μM CBZ. CBZ significantly increased hepatocyte viability after reperfusion. Confocal microscopy revealed that CBZ prevented calcium overloading, the onset of the MPT and mitochondrial depolarization. Immunoblotting and fluorometric analysis showed that CBZ blocked calpain activation, depletion of Atg7 and Beclin-1 and loss of autophagic flux after reperfusion. Intravital multiphoton imaging of anesthetized mice demonstrated that CBZ substantially reversed autophagic defects and mitochondrial dysfunction after I/R in vivo. In conclusion, CBZ prevents calcium overloading and calpain activation, which, in turn, suppresses Atg7 and Beclin-1 depletion, defective autophagy, onset of the MPT and cell death after I/R. - Highlights: • A mechanism of carbamazepine (CBZ)-induced cytoprotection in livers is proposed. • Impaired autophagy is a key event contributing to lethal reperfusion injury. • The importance of autophagy is extended and confirmed in an in vivo model. • CBZ is a potential

  16. miR-155 Affects Osteosarcoma MG-63 Cell Autophagy Induced by Adriamycin Through Regulating PTEN-PI3K/AKT/mTOR Signaling Pathway.

    Science.gov (United States)

    Wang, Lin; Tang, Bing; Han, Heng; Mao, Dan; Chen, Jie; Zeng, Yun; Xiong, Min

    2018-02-01

    Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) plays a positive regulatory role on cell autophagy through inhibiting PI3K/AKT/mammalian target of rapamycin (mTOR) signaling pathway. miR-155 plays a critical role in osteosarcoma occurrence and chemoresistance. Bioinformatics analysis revealed the targeted binding site between miR-155 and the 3'-UTR (untranslated region) of PTEN mRNA. This study investigated the role of miR-155 in regulating osteosarcoma cell autophagy, chemosensitivity to Adriamycin (ADM), and PTEN-PI3K/AKT/mTOR signaling pathway. Dual luciferase reporter gene assay confirmed the relationship between miR-155 and PTEN. MG-63 cells and drug-resistant MG-63/ADM cells were treated by ADM to compare miR-155, PTEN, p-AKT, p-mTOR, and Beclin-1 expressions. Cell apoptosis was tested by flow cytometry. MG-63/ADM cells were divided into five groups, including anti-miR-NC, anti-miR-155, pSicoR-blank, pSicoR-PTEN, and anti-miR-155+pSicoR-PTEN group. miR-155 targeted suppressed PTEN expression. miR-155, p-AKT, and p-mTOR significantly increased, while PTEN and Beclin-1 obviously reduced in MG-63/ADM cells compared with MG-63 cells. ADM treatment markedly elevated miR-155, p-AKT, and p-mTOR expressions, whereas reduced PTEN level. Beclin-1 was slightly upregulated, and autophagy and apoptosis levels were low. Anti-miR-155 and/or pSicoR-PTEN significantly enhanced PTEN and Beclin-1 expressions, cell apoptosis, and autophagy induced by ADM and declined p-AKT and p-mTOR levels. miR-155 targeted suppressed PTEN expression, enhanced PI3K/AKT/mTOR signaling pathway, inhibited cell apoptosis and autophagy induced by ADM, and reduced sensitivity to ADM.

  17. Inhibition of HDAC3- and HDAC6-promoted survivin expression plays an important role in SAHA-induced autophagy and viability reduction in breast cancer cells

    Directory of Open Access Journals (Sweden)

    Jane Ying-Chieh Lee

    2016-03-01

    Full Text Available SAHA is a class I HDAC/HDAC6 co-inhibitor and an autophagy inducer currently undergoing clinical investigations in breast cancer patients. However, the molecular mechanism of action of SAHA in breast cancer cells remains unclear. In this study, we found that SAHA is equally effective in targeting cells of different breast cancer subtypes and tamoxifen sensitivity. Importantly, we found that down-regulation of survivin plays an important role in SAHA-induced autophagy and cell viability reduction in human breast cancer cells. SAHA decreased survivin and XIAP gene transcription, induced survivin protein acetylation and early nuclear translocation in MCF7 and MDA-MB-231 breast cancer cells. It also reduced survivin and XIAP protein stability in part through modulating the expression and activation of the 26S proteasome and heat-shock protein 90. Interestingly, targeting HDAC3 and HDAC6, but not other HDAC isoforms, by siRNA/pharmacological inhibitors mimicked the effects of SAHA in modulating the acetylation, expression, and nuclear translocation of survivin and induced autophagy in MCF7 and MDA-MB-231 cancer cells. Targeting HDAC3 also mimicked the effect of SAHA in up-regulating the expression and activity of proteasome, which might lead to the reduced protein stability of survivin in breast cancer cells. In conclusion, this study provides new insights into SAHA’s molecular mechanism of actions in breast cancer cells. Our findings emphasize the complexity of the regulatory roles in different HDAC isoforms and potentially assist in predicting the mechanism of novel HDAC inhibitors in targeted or combinational therapies in the future.

  18. WNK1 is an unexpected autophagy inhibitor

    Science.gov (United States)

    Gallolu Kankanamalage, Sachith; Lee, A-Young; Wichaidit, Chonlarat; Lorente-Rodriguez, Andres; Shah, Akansha M.; Stippec, Steve; Whitehurst, Angelique W.; Cobb, Melanie H.

    2017-01-01

    ABSTRACT Autophagy is a cellular degradation pathway that is essential to maintain cellular physiology, and deregulation of autophagy leads to multiple diseases in humans. In a recent study, we discovered that the protein kinase WNK1 (WNK lysine deficient protein kinase 1) is an inhibitor of autophagy. The loss of WNK1 increases both basal and starvation-induced autophagy. In addition, the depletion of WNK1 increases the activation of the class III phosphatidylinositol 3-kinase (PtdIns3K) complex, which is required to induce autophagy. Moreover, the loss of WNK1 increases the expression of ULK1 (unc-51 like kinase 1), which is upstream of the PtdIns3K complex. It also increases the pro-autophagic phosphorylation of ULK1 at Ser555 and the activation of AMPK (AMP-activated protein kinase), which is responsible for that phosphorylation. The inhibition of AMPK by compound C decreases the magnitude of autophagy induction following WNK1 loss; however, it does not prevent autophagy induction. We found that the UVRAG (UV radiation resistance associated gene), which is a component of the PtdIns3K, binds to the N-terminal region of WNK1. Moreover, WNK1 partially colocalizes with UVRAG and this colocalization decreases when autophagy is stimulated in cells. The loss of WNK1 also alters the cellular distribution of UVRAG. The depletion of the downstream target of WNK1, OXSR1/OSR1 (oxidative-stress responsive 1) has no effect on autophagy, whereas the depletion of its relative STK39/SPAK (serine/threonine kinase 39) induces autophagy under nutrient-rich and starved conditions. PMID:28282258

  19. Polygonatum odoratum lectin induces apoptosis and autophagy by regulation of microRNA-1290 and microRNA-15a-3p in human lung adenocarcinoma A549 cells.

    Science.gov (United States)

    Wu, Lei; Liu, Tao; Xiao, Yan; Li, Xin; Zhu, Yanan; Zhao, Yan; Bao, Jinku; Wu, Chuanfang

    2016-04-01

    Polygonatum odoratum lectin (POL), a mannose-binding specific Galanthus nivalis agglutinin (GNA)-related lectin has been reported with remarkable anti-proliferative and apoptosis-inducing effects against several tumor cells. Our previous research revealed that POL can induce apoptosis and autophagy in A549 cells. However, whether microRNAs (miRNAs) are involved in POL-induced apoptosis and autophagy in A549 cells has not been investigated. The aim of this study was to evaluate whether miRNAs were involved in POL-induced apoptosis and autophagy in A549 cells. In the present study, we performed microarray analysis on A549 cells to identify altered miRNAs after POL treatment. We found that miR-1290 was down-regulated after POL treatment and down-regulated miR-1290 amplifies POL-induced apoptosis in A549 cells. Moreover, we revealed that glycogen synthase kinase-3β (GSK3β) was a direct target of miR-1290 and POL treatment could result in Wnt pathway down regulation. We also found that miR-15a-3p was up-regulated after POL treatment and over-expression of miR-15a-3p resulted in A549 cells apoptosis and autophagy. In addition, we confirmed that a miR-15a-3p mediated ROS-p53 pathway was involved in POL-induced apoptosis and autophagy in A549 cells. Taken together, these data provide evidence that POL induces A549 cells apoptosis and autophagy by regulation of miR-1290 and miR-15a-3p. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Targeting the Enterohepatic Bile Acid Signaling Induces Hepatic Autophagy via a CYP7A1–AKT–mTOR Axis in MiceSummary

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    Yifeng Wang

    2017-03-01

    Full Text Available Background & Aims: Hepatic cholesterol accumulation and autophagy defects contribute to hepatocyte injury in fatty liver disease. Bile acid synthesis is a major pathway for cholesterol catabolism in the liver. This study aims to understand the molecular link between cholesterol and bile acid metabolism and hepatic autophagy activity. Methods: The effects of cholesterol and cholesterol 7α-hydroxylase (CYP7A1 expression on autophagy and lysosome function were studied in cell models. The effects and mechanism of disrupting enterohepatic bile acid circulation on hepatic autophagy were studied in mice. Results: The results first showed differential regulation of hepatic autophagy by free cholesterol and cholesterol ester, whereby a modest increase of cellular free cholesterol, but not cholesterol ester, impaired lysosome function and caused marked autolysosome accumulation. We found that CYP7A1 induction, either by cholestyramine feeding in mice or adenovirus-mediated CYP7A1 expression in hepatocytes, caused strong autophagy induction. Mechanistically, we showed that CYP7A1 expression markedly attenuated growth factor/AKT signaling activation of mechanistic target of rapamycin (mTOR, but not amino acid signaling to mTOR in vitro and in vivo. Metabolomics analysis further found that CYP7A1 induction not only decreased hepatic cholesterol but also altered phospholipid and sphingolipid compositions. Collectively, these results suggest that CYP7A1 induction interferes with growth factor activation of AKT/mTOR signaling possibly by altering membrane lipid composition. Finally, we showed that cholestyramine feeding restored impaired hepatic autophagy and improved metabolic homeostasis in Western diet–fed mice. Conclusions: This study identified a novel CYP7A1–AKT–mTOR signaling axis that selectively induces hepatic autophagy, which helps improve hepatocellular integrity and metabolic homeostasis. Keywords: Cholesterol

  1. Autophagy induction contributes to GDC-0349 resistance in head and neck squamous cell carcinoma (HNSCC) cells

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    Zhou, Yajuan; Peng, Yi [Department of Radiation Oncology, Hubei Cancer Hospital, Wuhan (China); Tang, Hao [Department of Pathology, Hubei Cancer Hospital, Wuhan 430071 (China); He, Xiaojun; Wang, Zhaohua [Department of Radiation Oncology, Hubei Cancer Hospital, Wuhan (China); Hu, Desheng, E-mail: hudeshengvvip@sina.com [Department of Radiation Oncology, Hubei Cancer Hospital, Wuhan (China); Zhou, Xiaoyi, E-mail: zhouxy1218@126.com [Department of Radiation Oncology, Hubei Cancer Hospital, Wuhan (China)

    2016-08-19

    Dysregulation of mammalian target of rapamycin (mTOR) signaling contributes to head and neck squamous cell carcinoma (HNSCC) tumorigenesis and progression. In the current study, we tested the anti-HNSCC cell activity by GDC-0349, a selective ATP-competitive inhibitor of mTOR. We showed that GDC-0349 inhibited proliferation of established and primary human HNSCC cells bearing high-level of p-AKT/p-S6K. Further, it induced caspase-dependent apoptosis in the HNSCC cells. GDC-0349 blocked mTORC1 and mTORC2 activation, yet it simultaneously induced autophagy activation in HNSCC cells. The latter was evidenced by induction of LC3B-II, Beclin-1 and Autophagy-related (ATG)-7, as well as downregulation of p62. Autophagy inhibitors (3-methyladenine and bafilomycin A1) or ATG-7 siRNA dramatically potentiated GDC-0349’s cytotoxicity against HNSCC cells. Intriguingly, we showed that ceramide (C14), a pro-apoptotic sphingolipid, also induced ATG-7 degradation, and sensitized HNSCC cells to GDC-0349. Collectively, the preclinical study provided evidences to support GDC-0349 as a promising anti-HNSCC agent. GDC-0349 sensitization may be achieved via autophagy inhibition. - Highlights: • GDC-0349 inhibits proliferation of HNSCC cells bearing high-level of p-AKT/p-S6K. • GDC-0349 activates caspase-dependent apoptosis in HNSCC cells. • Simultaneous blockage of mTORC1/2 by GDC-0349 induces autophagy activation. • Autophagy inhibitor or ATG-7 siRNA potentiates GDC-0349’s cytotoxicity. • C14 ceramide downregulates ATG-7 and sensitizes HNSCC cells to GDC-0349.

  2. The autophagy induced by curcumin via MEK/ERK pathway plays an early anti-leukemia role in human Philadelphia chromosome-positive acute lymphoblastic leukemia SUP-B15 cells

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    Yong Guo

    2018-01-01

    Conclusions: Curcumin induce autophagic cell death in SUP-B15 cells via activating RAF/MEK/ERK pathway. These findings suggest that autophagic mechanism contribute to the curcumin-induced early SUP-B15 cell death, and autophagy is another anti-leukemia mechanism of curcumin.

  3. Chemotherapy-induced pulmonary hypertension: role of alkylating agents.

    Science.gov (United States)

    Ranchoux, Benoît; Günther, Sven; Quarck, Rozenn; Chaumais, Marie-Camille; Dorfmüller, Peter; Antigny, Fabrice; Dumas, Sébastien J; Raymond, Nicolas; Lau, Edmund; Savale, Laurent; Jaïs, Xavier; Sitbon, Olivier; Simonneau, Gérald; Stenmark, Kurt; Cohen-Kaminsky, Sylvia; Humbert, Marc; Montani, David; Perros, Frédéric

    2015-02-01

    Pulmonary veno-occlusive disease (PVOD) is an uncommon form of pulmonary hypertension (PH) characterized by progressive obstruction of small pulmonary veins and a dismal prognosis. Limited case series have reported a possible association between different chemotherapeutic agents and PVOD. We evaluated the relationship between chemotherapeutic agents and PVOD. Cases of chemotherapy-induced PVOD from the French PH network and literature were reviewed. Consequences of chemotherapy exposure on the pulmonary vasculature and hemodynamics were investigated in three different animal models (mouse, rat, and rabbit). Thirty-seven cases of chemotherapy-associated PVOD were identified in the French PH network and systematic literature analysis. Exposure to alkylating agents was observed in 83.8% of cases, mostly represented by cyclophosphamide (43.2%). In three different animal models, cyclophosphamide was able to induce PH on the basis of hemodynamic, morphological, and biological parameters. In these models, histopathological assessment confirmed significant pulmonary venous involvement highly suggestive of PVOD. Together, clinical data and animal models demonstrated a plausible cause-effect relationship between alkylating agents and PVOD. Clinicians should be aware of this uncommon, but severe, pulmonary vascular complication of alkylating agents. Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  4. Sigma-1 and Sigma-2 receptor ligands induce apoptosis and autophagy but have opposite effect on cell proliferation in uveal melanoma.

    Science.gov (United States)

    Longhitano, Lucia; Castracani, Carlo Castruccio; Tibullo, Daniele; Avola, Roberto; Viola, Maria; Russo, Giuliano; Prezzavento, Orazio; Marrazzo, Agostino; Amata, Emanuele; Reibaldi, Michele; Longo, Antonio; Russo, Andrea; Parrinello, Nunziatina Laura; Volti, Giovanni Li

    2017-10-31

    Uveal melanoma is the most common primary intraocular tumor in adults, with about 1200-1500 new cases occurring per year in the United States. Metastasis is a frequent occurrence in uveal melanoma, and outcomes are poor once distant spread occurs and no clinically significant chemotherapeutic protocol is so far available. The aim of the present study was to test the effect of various σ 1 and σ 2 receptor ligands as a possible pharmacological strategy for this rare tumor. Human uveal melanoma cells (92.1) were treated with various concentrations of different σ 2 ligands (haloperidol and haloperidol metabolite II) and σ 1 ligand ((+)-pentazocine) at various concentrations (1, 10 and 25 μM) and time points (0, 4 h, 8 h, 24 h and 48 h). Cell proliferation and migration were evaluated respectively by continuous cell monitoring by xCELLigence analysis, clonogenic assay and wound healing. Apoptosis and autophagy were also measured by cytofluorimetric and microscopy analysis. Our results showed that σ 2 receptor ligands significantly reduced cell proliferation whereas (+)-pentazocine exhibited opposite results. All tested ligands showed significant decrease in cell migration. Interestingly, both σ 1 and σ 2 receptor ligands showed significant increase of autophagy and apoptosis at all concentrations. Taken all together these results suggest that sigma receptors mediates opposite biological effects but they also share common pharmacological effect on apoptosis and autophagy in uveal melanoma. In conclusion, these data provide the first evidence that sigma receptors may represent a "druggable" target to develop new chemotherapic agent for uveal melanoma.

  5. Cucurbitane Triterpenoid from Momordica charantia Induces Apoptosis and Autophagy in Breast Cancer Cells, in Part, through Peroxisome Proliferator-Activated Receptor γ Activation

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    Jing-Ru Weng

    2013-01-01

    Full Text Available Although the antitumor activity of the crude extract of wild bitter gourd (Momordica charantia L. has been reported, its bioactive constituents and the underlying mechanism remain undefined. Here, we report that 3β,7β-dihydroxy-25-methoxycucurbita-5,23-diene-19-al (DMC, a cucurbitane-type triterpene isolated from wild bitter gourd, induced apoptotic death in breast cancer cells through peroxisome proliferator-activated receptor (PPAR γ activation. Luciferase reporter assays indicated the ability of DMC to activate PPARγ, and pharmacological inhibition of PPARγ protected cells from DMC's antiproliferative effect. Western blot analysis indicated that DMC suppressed the expression of many PPARγ-targeted signaling effectors, including cyclin D1, CDK6, Bcl-2, XIAP, cyclooxygenase-2, NF-κB, and estrogen receptor α, and induced endoplasmic reticulum stress, as manifested by the induction of GADD153 and GRP78 expression. Moreover, DMC inhibited mTOR-p70S6K signaling through Akt downregulation and AMPK activation. The ability of DMC to activate AMPK in liver kinase (LK B1-deficient MDA-MB-231 cells suggests that this activation was independent of LKB1-regulated cellular metabolic status. However, DMC induced a cytoprotective autophagy presumably through mTOR inhibition, which could be overcome by the cotreatment with the autophagy inhibitor chloroquine. Together, the ability of DMC to modulate multiple PPARγ-targeted signaling pathways provides a mechanistic basis to account for the antitumor activity of wild bitter gourd.

  6. Cucurbitacin B inhibits proliferation, induces G2/M cycle arrest and autophagy without affecting apoptosis but enhances MTT reduction in PC12 cells

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    Chuanhong Wu

    2016-03-01

    Full Text Available In the present study, the effect of cucurbitacin B (a natural product with anti-cancer effect was studied on PC12 cells. It significantly reduced the cell number, changed cell morphology and inhibited colony formation while MTT results showed increased cell viability. Cucurbitacin B treatment increased activity of succinode hydrogenase. No alteration in the integrity of mem-brane, the release of lactic dehydrogenase, the mitochondrial membrane potential, and the expression of apoptotic proteins suggested that cucurbitacin B did not induce apoptosis. The cell cycle was remarkably arrested at G2/M phase. Furthermore, cucurbitacin B induced autophagy as evidence by accumulation