101
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Awan MUF, Deng Y. Role of autophagy and its significance in cellular homeostasis. Appl Microbiol Biotechnol 2014; 98:5319-28. [PMID: 24743981 DOI: 10.1007/s00253-014-5721-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/21/2014] [Accepted: 03/22/2014] [Indexed: 12/18/2022]
Abstract
Autophagy is a catabolic pathway that regulates homeostasis in cells. It is an exceptional pathway of membrane trafficking. Autophagy is characterized by the formation of double-membrane vesicles; autophagosomes that are responsible for delivering damaged organelle and extra proteins to lysosome for recycling. A series of actions including environmental and genetic factors are responsible for induction of autophagy. In the past few decades, the research on autophagy has been immensely expanded because it is a vital process in maintaining cellular balance as well as deeply connected with pathogenesis of a number of diseases. The aim of this review is to present an overview of modern work on autophagy and highlight some essential genetic role in the induction of autophagy. There is an emerging need to identify, quantify, and manipulate the pathway of autophagy, due to its close relationship with a variety of developmental pathways and functions especially in cancer, diabetes, neurodegenerative disorders, and infectious diseases.
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Affiliation(s)
- M Umer Farooq Awan
- School of Life Sciences, Beijing Institute of Technology, No. 5 Zhongguancunn South Street, Beijing, 100081, People's Republic of China
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102
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Wang Y, Zhan Y, Xu R, Shao R, Jiang J, Wang Z. Src mediates extracellular signal-regulated kinase 1/2 activation and autophagic cell death induced by cardiac glycosides in human non-small cell lung cancer cell lines. Mol Carcinog 2014; 54 Suppl 1:E26-34. [DOI: 10.1002/mc.22147] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 02/04/2014] [Accepted: 02/17/2014] [Indexed: 12/18/2022]
Affiliation(s)
- Yan Wang
- Biochemistry Department; Institute of Medicinal Biotechnology; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing P.R. China
- Pharmacology Department; Institute of Materia Medica; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing P.R. China
| | - Yuechen Zhan
- Biochemistry Department; Institute of Medicinal Biotechnology; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing P.R. China
| | - Rong Xu
- Biochemistry Department; Institute of Medicinal Biotechnology; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing P.R. China
| | - Rongguang Shao
- Biochemistry Department; Institute of Medicinal Biotechnology; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing P.R. China
| | - Jiandong Jiang
- Biochemistry Department; Institute of Medicinal Biotechnology; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing P.R. China
- Pharmacology Department; Institute of Materia Medica; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing P.R. China
| | - Zhen Wang
- Biochemistry Department; Institute of Medicinal Biotechnology; Chinese Academy of Medical Sciences & Peking Union Medical College; Beijing P.R. China
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103
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Harder LM, Bunkenborg J, Andersen JS. Inducing autophagy: a comparative phosphoproteomic study of the cellular response to ammonia and rapamycin. Autophagy 2013; 10:339-55. [PMID: 24300666 PMCID: PMC5396081 DOI: 10.4161/auto.26863] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Autophagy is a lysosomal-mediated catabolic process, which through degradation of different cytoplasmic components aids in maintaining cellular homeostasis and survival during exposure to extra- or intracellular stresses. Ammonia is a potential toxic and stress-inducing byproduct of glutamine 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 activity was not affected, but indicated increased MAPK3 activity, regulation of proteins involved in Rho signal transduction, and a novel phosphorylation motif, serine-proline-threonine (SPT), which could be linked to cytoskeleton-associated proteins. MAPK3 could not be identified as the primary driver of ammonia-induced autophagy but instead the data suggested an upregulation of AMPK and the unfolded protein response (UPR), which might link ammonia to autophagy induction. Support of UPR induction was further obtained from the finding of increased protein levels of the ER stress markers DDIT3/CHOP and HSPA5 during ammonia treatment. The large-scale data set presented here comprises extensive high-quality quantitative information on phosphoprotein regulation in response to 2 very different autophagy inducers and should therefore be considered a general resource for the community.
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Affiliation(s)
- Lea M Harder
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense, Denmark
| | - Jakob Bunkenborg
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense, Denmark
| | - Jens S Andersen
- Department of Biochemistry and Molecular Biology; University of Southern Denmark; Odense, Denmark
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104
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Vitale N, Kisslinger A, Paladino S, Procaccini C, Matarese G, Pierantoni GM, Mancini FP, Tramontano D. Resveratrol couples apoptosis with autophagy in UVB-irradiated HaCaT cells. PLoS One 2013; 8:e80728. [PMID: 24260465 PMCID: PMC3834311 DOI: 10.1371/journal.pone.0080728] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 10/07/2013] [Indexed: 12/17/2022] Open
Abstract
UVB radiation causes about 90% of non-melanoma skin cancers by damaging DNA either directly or indirectly by increasing levels of reactive oxygen species (ROS). Skin, chronically exposed to both endogenous and environmental pro-oxidant agents, contains a well-organised system of chemical and enzymatic antioxidants. However, increased or prolonged free radical action can overwhelm ROS defence mechanisms, contributing to the development of cutaneous diseases. Thus, new strategies for skin protection comprise the use of food antioxidants to counteract oxidative stress. Resveratrol, a phytoalexin from grape, has gained a great interest for its ability to influence several biological mechanisms like redox balance, cell proliferation, signal transduction pathways, immune and inflammatory response. Therefore, the potential of resveratrol to modify skin cell response to UVB exposure could turn out to be a useful option to protect skin from sunlight-induced degenerative diseases. To investigate into this matter, HaCaT cells, a largely used model for human skin keratinocytes, were treated with 25 or 100 µM resveratrol for 2 and 24 hours prior to UVB irradiation (10 to 100 mJ/cm2). Cell viability and molecular markers of proliferation, oxidative stress, apoptosis, and autophagy were analyzed. In HaCaT cells resveratrol pretreatment: reduces UVB-induced ROS formation, enhances the detrimental effect of UVB on HaCaT cell vitality, increases UVB-induced caspase 8, PARP cleavage, and induces autophagy. These findings suggest that resveratrol could exert photochemopreventive effects by enhancing UVB-induced apoptosis and by inducing autophagy, thus reducing the odds that damaged cells could escape programmed cell death and initiate malignant transformation.
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Affiliation(s)
- Nicoletta Vitale
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
| | | | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
| | - Claudio Procaccini
- Institute of Oncology and Experimental Endocrinology, CNR, Naples, Italy
| | - Giuseppe Matarese
- Department of Medicine and Surgery, University of Salerno, Baronissi Campus, Salerno, Italy
- IRCCS MultiMedica, Milan, Italy
| | - Giovanna Maria Pierantoni
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
| | | | - Donatella Tramontano
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples “Federico II”, Naples, Italy
- * E-mail:
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105
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Chua JP, Reddy SL, Merry DE, Adachi H, Katsuno M, Sobue G, Robins DM, Lieberman AP. Transcriptional activation of TFEB/ZKSCAN3 target genes underlies enhanced autophagy in spinobulbar muscular atrophy. Hum Mol Genet 2013; 23:1376-86. [PMID: 24150846 DOI: 10.1093/hmg/ddt527] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Spinobulbar muscular atrophy (SBMA) is an inherited neuromuscular disorder caused by the expansion of a CAG repeat encoding a polyglutamine tract in exon 1 of the androgen receptor (AR) gene. SBMA demonstrates androgen-dependent toxicity due to unfolding and aggregation of the mutant protein. There are currently no disease-modifying therapies, but of increasing interest for therapeutic targeting is autophagy, a highly conserved cellular process mediating protein quality control. We have previously shown that genetic manipulations inhibiting autophagy diminish skeletal muscle atrophy and extend the lifespan of AR113Q knock-in mice. In contrast, manipulations inducing autophagy worsen muscle atrophy, suggesting that chronic, aberrant upregulation of autophagy contributes to pathogenesis. Since the degree to which autophagy is altered in SBMA and the mechanisms responsible for such alterations are incompletely defined, we sought to delineate autophagic status in SBMA using both cellular and mouse models. Here, we confirm that autophagy is induced in cellular and knock-in mouse models of SBMA and show that the transcription factors transcription factor EB (TFEB) and ZKSCAN3 operate in opposing roles to underlie these changes. We demonstrate upregulation of TFEB target genes in skeletal muscle from AR113Q male mice and SBMA patients. Furthermore, we observe a greater response in AR113Q mice to physiological stimulation of autophagy by both nutrient starvation and exercise. Taken together, our results indicate that transcriptional signaling contributes to autophagic dysregulation and provides a mechanistic framework for the pathologic increase of autophagic responsiveness in SBMA.
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106
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Ahn JH, Lee M. Autophagy-Dependent Survival of Mutant B-Raf Melanoma Cells Selected for Resistance to Apoptosis Induced by Inhibitors against Oncogenic B-Raf. Biomol Ther (Seoul) 2013; 21:114-20. [PMID: 24009868 PMCID: PMC3762312 DOI: 10.4062/biomolther.2013.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 03/13/2013] [Accepted: 03/13/2013] [Indexed: 01/16/2023] Open
Abstract
Most patients with mutant B-Raf melanomas respond to inhibitors of oncogenic B-Raf but resistance eventually emerges. To better understand the mechanisms that determine the long-term responses of mutant B-Raf melanoma cells to B-Raf inhibitor, we used chronic selection to establish B-Raf (V600E) melanoma clones with acquired resistance to the new oncogenic B-Raf inhibitor UI-152. Whereas the parental A375P cells were highly sensitive to UI-152 (IC50<0.5 μM), the resistant sub-line (A375P/Mdr) displayed strong resistance to UI-152 (IC50>20 μM). Immunofluorescence analysis indicated the absence of an increase in the levels of P-glycoprotein multidrug resistance (MDR) transporter in A375P/Mdr cells, suggesting that resistance was not attributable to P-glycoprotein overexpression. In UI-152-sensitive A375P cells, the anti-proliferative activity of UI-152 appeared to be due to cell-cycle arrest at G0/G1 with the induction of apoptosis. However, we found that A375P/Mdr cells were resistant to the apoptosis induced by UI-152. Interestingly, UI-152 preferentially induced autophagy in A375P/Mdr cells but not in A375P cells, as determined by GFP-LC3 puncta/cell counts. Further, autophagy inhibition with 3-methyladenine (3-MA) partially augmented growth inhibition of A375P/Mdr cells by UI-152, which implies that a high level of autophagy may protect UI-152-treated cells from undergoing growth inhibition. Together, our data implicate high rates of autophagy as a key mechanism of acquired resistance to the oncogenic B-Raf inhibitor, in support of clinical studies in which combination therapy with autophagy targeted drugs is being designed to overcome resistance.
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Affiliation(s)
- Jun-Ho Ahn
- Division of Life Sciences, College of Life Sciences and Bioengineering, University of Incheon, Incheon 406-772, Republic of Korea
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107
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Zheng Z, Yang J, Zhao D, Gao D, Yan X, Yao Z, Liu Z, Ma Z. Downregulated adaptor protein p66(Shc) mitigates autophagy process by low nutrient and enhances apoptotic resistance in human lung adenocarcinoma A549 cells. FEBS J 2013; 280:4522-30. [PMID: 23815759 DOI: 10.1111/febs.12416] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 04/11/2013] [Accepted: 06/25/2013] [Indexed: 12/31/2022]
Abstract
Macroautophagy or autophagy is a lysosome-dependent process in which enzymatic degradation and recycling of cytosolic components occur in stressful contexts. The mechanisms underlying the signaling from starvation to the regulation of autophagy are not fully understood. We previously showed that the Src family member p66(Shc) (focal adhesion-associated 66 kDa isoform of the Src homology and collagen) promotes anoikis and suppresses tumor metastasis via k-Ras-dependent control of proliferation and survival. However, the role of p66(Shc) in low-nutrient-induced autophagy-related pathways remains elusive. In this work, human lung adenocarcinoma A549 cells were used to further investigate the biological effects of p66(Shc) on autophagy and apoptotic resistance. Here, we show that deficiency of p66(Shc) mitigates the low-nutrient-induced autophagy process in the levels of microtubule-associated protein 1A light chain protein 3B (LC3B) conversion, in the number of autophagic vacuoles and in p62/sequestosome 1 protein degradation. However, autophagy-related protein Beclin 1 was not significantly changed during low-nutrient treatment. Furthermore, we found that prolonged phosphorylation of extracellular signaling-regulated kinase (Erk)1/2, but not phosphorylation of Akt is significantly sustained when p66(Shc) expression is inhibited by shRNA. In addition, cleavage of caspase 7 and poly(ADP-ribose) polymerase, but not caspase 6 and 9 are retarded with this effect compared to the shRNA control cells. Together, these findings suggest the possibility that p66(Shc) plays a pivotal role in coordinately regulating autophagy process and apoptotic resistance in A549 cells under nutrient-limited conditions.
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Affiliation(s)
- Zhichao Zheng
- Tianjin Key Laboratory of Medical Epigenetics, Tianjin Medical University, China
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108
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Essick EE, Wilson RM, Pimentel DR, Shimano M, Baid S, Ouchi N, Sam F. Adiponectin modulates oxidative stress-induced autophagy in cardiomyocytes. PLoS One 2013; 8:e68697. [PMID: 23894332 PMCID: PMC3716763 DOI: 10.1371/journal.pone.0068697] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 06/02/2013] [Indexed: 11/18/2022] Open
Abstract
Diastolic heart failure (HF) i.e., "HF with preserved ejection fraction" (HF-preserved EF) accounts for up to 50% of all HF presentations; however there have been no therapeutic advances. This stems in part from an incomplete understanding about HF-preserved EF. Hypertension is the major cause of HF-preserved EF whilst HF-preserved EF is also highly associated with obesity. Similarly, excessive reactive oxygen species (ROS), i.e., oxidative stress occurs in hypertension and obesity, sensitizing the heart to the renin-angiotensin-aldosterone system, inducing autophagic type-II programmed cell death and accelerating the propensity to adverse cardiac remodeling, diastolic dysfunction and HF. Adiponectin (APN), an adipokine, mediates cardioprotective actions but it is unknown if APN modulates cardiomyocyte autophagy. We tested the hypothesis that APN ameliorates oxidative stress-induced autophagy in cardiomyocytes. Isolated adult rat ventricular myocytes were pretreated with recombinant APN (30 µg/mL) followed by 1mM hydrogen peroxide (H2O2) exposure. Wild type (WT) and APN-deficient (APN-KO) mice were infused with angiotensin (Ang)-II (3.2 mg/kg/d) for 14 days to induced oxidative stress. Autophagy-related proteins, mTOR, AMPK and ERK expression were measured. H2O2 induced LC3I to LC3II conversion by a factor of 3.4±1.0 which was abrogated by pre-treatment with APN by 44.5±10%. However, neither H2O2 nor APN affected ATG5, ATG7, or Beclin-1 expression. H2O2 increased phospho-AMPK by 49±6.0%, whilst pretreatment with APN decreased phospho-AMPK by 26±4%. H2O2 decreased phospho-mTOR by 36±13%, which was restored by APN. ERK inhibition demonstrated that the ERK-mTOR pathway is involved in H2O2-induced autophagy. Chronic Ang-II infusion significantly increased myocardial LC3II/I protein expression ratio in APN-KO vs. WT mice. These data suggest that excessive ROS caused cardiomyocyte autophagy which was ameliorated by APN by inhibiting an H2O2-induced AMPK/mTOR/ERK-dependent mechanism. These findings demonstrate the anti-oxidant potential of APN in oxidative stress-associated cardiovascular diseases, such as hypertension-induced HF-preserved EF.
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Affiliation(s)
- Eric E. Essick
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Richard M. Wilson
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - David R. Pimentel
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Cardiovascular Section and Evans Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Masayuki Shimano
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Simoni Baid
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Noriyuki Ouchi
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Flora Sam
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Cardiovascular Section and Evans Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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109
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Promotion of autophagy at the maturation step by IL-6 is associated with the sustained mitogen-activated protein kinase/extracellular signal-regulated kinase activity. Mol Cell Biochem 2013; 380:219-27. [PMID: 23677697 DOI: 10.1007/s11010-013-1676-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Accepted: 05/02/2013] [Indexed: 12/19/2022]
Abstract
Increased autophagic vacuoles (AVs) occur in injured or degenerating neurons, under both developmental and pathological situations. Although an induced autophagy has been shown in inflammation response to cell factors, the underlying mechanism(s) remain(s) unknown. Here, we show that both cell factor IL-6 and environmental toxin MPP(+) promote the formation of vacuolation in SHSY5Y cells. By electron and immunofluorescent microscopy analyses, we showed that these structures are acid autolysosomes, containing cellular debris, and labeled by LC3 or LAMP1, markers of autophagosomes or lysosomes, respectively. Combining MPP(+) and IL-6 do not further increase vacuolation of SHSY5Y cells, and the vacuolation is less than that in the MPP(+)-treated group. MPP(+)-induced vacuolation results from significant increase in autophagy formation and delay in autophagy degradation, in relation to a decline of the lysosomal activity of arylsulfatase A. At molecular level, we show that this defect in autolysosomal maturation is independent of mammalian target of rapamycin and p38 inhibitions. Most importantly, we provide the first evidence that activation of ERK pathway is sufficient to commit cell to autophagic vacuolation. The sustained activation is required for MPP(+) to disrupt the autophagic pathway. IL-6 also induces a temporary and significant activation of ERK, but not sustained activation, and change sustained activation in MPP(+)-treated group into temporary activation. Taken together, these findings strongly support that IL-6 promotes the maturation of autophagosomes into functional autolysosomes by regulating ERK.
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110
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Balasubramanian MN, Butterworth EA, Kilberg MS. Asparagine synthetase: regulation by cell stress and involvement in tumor biology. Am J Physiol Endocrinol Metab 2013; 304:E789-99. [PMID: 23403946 PMCID: PMC3625782 DOI: 10.1152/ajpendo.00015.2013] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Asparagine synthetase (ASNS) catalyzes the conversion of aspartate and glutamine to asparagine and glutamate in an ATP-dependent reaction. The enzyme is ubiquitous in its organ distribution in mammals, but basal expression is relatively low in tissues other than the exocrine pancreas. Human ASNS activity is highly regulated in response to cell stress, primarily by increased transcription from a single gene located on chromosome 7. Among the genomic elements that control ASNS transcription is the C/EBP-ATF response element (CARE) within the promoter. Protein limitation or an imbalanced dietary amino acid composition activate the ASNS gene through the amino acid response (AAR), a process that is replicated in cell culture through limitation for any single essential amino acid. Endoplasmic reticulum stress also increases ASNS transcription through the PERK-eIF2-ATF4 arm of the unfolded protein response (UPR). Both the AAR and UPR lead to increased synthesis of ATF4, which binds to the CARE and induces ASNS transcription. Elevated expression of ASNS protein is associated with resistance to asparaginase therapy in childhood acute lymphoblastic leukemia and may be a predictive factor in drug sensitivity for certain solid tumors as well. Activation of the GCN2-eIF2-ATF4 signaling pathway, leading to increased ASNS expression appears to be a component of solid tumor adaptation to nutrient deprivation and/or hypoxia. Identifying the roles of ASNS in fetal development, tissue differentiation, and tumor growth may reveal that ASNS function extends beyond asparagine biosynthesis.
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Affiliation(s)
- Mukundh N Balasubramanian
- Department of Biochemistry and Molecular Biology, Shands Cancer Center and Center for Nutritional Sciences, University of Florida College of Medicine, Gainesville, FL 32610, USA
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111
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Dokladny K, Zuhl MN, Mandell M, Bhattacharya D, Schneider S, Deretic V, Moseley PL. Regulatory coordination between two major intracellular homeostatic systems: heat shock response and autophagy. J Biol Chem 2013; 288:14959-72. [PMID: 23576438 DOI: 10.1074/jbc.m113.462408] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The eukaryotic cell depends on multitiered homeostatic systems ensuring maintenance of proteostasis, organellar integrity, function and turnover, and overall cellular viability. At the two opposite ends of the homeostatic system spectrum are heat shock response and autophagy. Here, we tested whether there are interactions between these homeostatic systems, one universally operational in all prokaryotic and eukaryotic cells, and the other one (autophagy) is limited to eukaryotes. We found that heat shock response regulates autophagy. The interaction between the two systems was demonstrated by testing the role of HSF-1, the central regulator of heat shock gene expression. Knockdown of HSF-1 increased the LC3 lipidation associated with formation of autophagosomal organelles, whereas depletion of HSF-1 potentiated both starvation- and rapamycin-induced autophagy. HSP70 expression but not expression of its ATPase mutant inhibited starvation or rapamycin-induced autophagy. We also show that exercise induces autophagy in humans. As predicted by our in vitro studies, glutamine supplementation as a conditioning stimulus prior to exercise significantly increased HSP70 protein expression and prevented the expected exercise induction of autophagy. Our data demonstrate for the first time that heat shock response, from the top of its regulatory cascade (HSF-1) down to the execution stages delivered by HSP70, controls autophagy thus connecting and coordinating the two extreme ends of the homeostatic systems in the eukaryotic cell.
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Affiliation(s)
- Karol Dokladny
- Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA
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112
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Raina K, Agarwal C, Wadhwa R, Serkova NJ, Agarwal R. Energy deprivation by silibinin in colorectal cancer cells: a double-edged sword targeting both apoptotic and autophagic machineries. Autophagy 2013; 9:697-713. [PMID: 23445752 DOI: 10.4161/auto.23960] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Small molecules with the potential to initiate different types of programmed cell death could be useful 'adjunct therapy' where current anticancer modalities fail to generate significant activity due to a defective apoptotic machinery or resistance of cancer cells to the specific death mechanism induced by that treatment. The current study identified silibinin, for the first time, as one such natural agent, having dual efficacy against colorectal cancer (CRC) cells. First, silibinin rapidly induced oxidative stress in CRC SW480 cells due to reactive oxygen species (ROS) generation with a concomitant dissipation of mitchondrial potential (ΔΨm) and cytochrome c release leading to mild apoptosis as a biological effect. However, with increased exposure to silibinin, cytoplasmic vacuolization intensified within the cells followed by sequestration of the organelles, which inhibits the further release of cytochrome c. Interestingly, this decrease in apoptotic response correlated with increased autophagic events as evidenced by tracking the dynamics of LC3-II within the cells. Mechanistic studies revealed that silibinin strongly inhibited PIK3CA-AKT-MTOR but activated MAP2K1/2-MAPK1/3 pathways for its biological effects. Corroborating these effects, endoplasmic reticulum stress was generated and glucose uptake inhibition as well as energy restriction were induced by silibinin, thus, mimicking starvation-like conditions. Further, the cellular damage to tumor cells by silibinin was severe and irreparable due to sustained interference in essential cellular processes such as mitochondrial metabolism, phospholipid and protein synthesis, suggesting that silibinin harbors a deadly 'double-edged sword' against CRC cells thereby further advocating its clinical effectiveness against this malignancy.
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Affiliation(s)
- Komal Raina
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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113
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Li Y, Zhang J, Ma H, Chen X, Liu T, Jiao Z, He W, Wang F, Liu X, Zeng X. Protective role of autophagy in matrine‑induced gastric cancer cell death. Int J Oncol 2013; 42:1417-26. [PMID: 23404079 DOI: 10.3892/ijo.2013.1817] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 12/07/2012] [Indexed: 11/06/2022] Open
Abstract
Matrine has potent antitumor activity against a broad variety of cancer cells and our previous study showed that both autophagy and apoptosis were activated during matrine-induced gastric cancer cell death. The aim of the present study was to determine the significance of autophagy in antineoplastic effects of matrine and the molecular mechanism by which matrine induces autophagy in gastric cancer cells. Western blot analysis showed that exposure of gastric cancer cells to matrine resulted in the extent of autophagy increasing in a dose- and time-dependent manner by detecting micro-tubule-associated protein 1 light chain 3 (LC3). This induction was due to activation of autophagic flux, as supported using the lysosome inhibitor, bafilomycin A1, which produced an accumulation of LC3-II. Propidium iodide staining demonstrated that matrine induced cell death in a dose-dependent manner and the autophagy inhibitor 3-methyladenine (3-MA) or bafilomycin A1 enhanced lethality of matrine against gastric cancer cells. Moreover, after pretreatment with 3-MA, some of the gastric cancer cells treated with matrine exhibited prototypical characteristics of apoptosis by transmission electron microscopy. The ability of 3-MA to increase matrine-induced apoptosis was further confirmed by Annexin V-FITC/PI staining. Also, the combination of matrine and 3-MA was more potent than matrine alone in inhibiting the proliferation of SGC-7901 cells assessed by sulphorhodamine B assay. Furthermore, administration of the pan-caspase inhibitor zVAD-fmk or autophagy inducer rapamycin decreased the matrine-induced cell death. In addition, matrine treatment did not inhibit the phosphorylation of Akt and its downstream effectors mammalian target of rapamycin (mTOR) as well as p70 ribosomal protein S6 kinase (p70S6K), although the levels of the total Akt and mTOR were decreased. These results suggest that autophagy was activated as a protective mechanism against matrine-induced apoptosis and inhibition of autophagy may be an attractive strategy for enhancing the antitumor potential of matrine in gastric cancer.
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Affiliation(s)
- Yumin Li
- The Second Hospital of Lanzhou University, Lanzhou, Gansu 730030, P.R. China.
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114
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Suppression of autophagy enhanced growth inhibition and apoptosis of interferon-β in human glioma cells. Mol Neurobiol 2013; 47:1000-10. [PMID: 23329343 DOI: 10.1007/s12035-013-8403-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 01/03/2013] [Indexed: 12/19/2022]
Abstract
Interferon-beta (IFN-β) is a cytokine with anti-viral, anti-proliferative, and immunomodulatory effects. In this study, we investigated the effects of IFN-β on the induction of autophagy and the relationships among autophagy, growth inhibition, and apoptosis induced by IFN-β in human glioma cells. We found that IFN-β induced autophagosome formation and conversion of microtubule associated protein 1 light chain 3 (LC3) protein, whereas it inhibited cell growth through caspase-dependent cell apoptosis. The Akt/mTOR signaling pathway was involved in autophagy induced by IFN-β. A dose- and time-dependent increase of p-ERK 1/2 expression was also observed in human glioma cells treated with IFN-β. Autophagy induced by IFN-β was suppressed when p-ERK1/2 was impaired by treatment with U0126. We also demonstrated that suppression of autophagy significantly enhanced growth inhibition and cell apoptosis induced by IFN-β, whereas inhibition of caspase-dependent cell apoptosis impaired autophagy induced by IFN-β. Collectively, these findings indicated that autophagy induced by IFN-β was associated with the Akt/mTOR and ERK 1/2 signaling pathways, and inhibition of autophagy could enhance the growth inhibitory effects of IFN-β and increase apoptosis in human glioma cells. Together, these findings support the possibility that autophagy inhibitors may improve IFN-β therapy for gliomas.
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115
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ABE AKIHISA, KOKUBA HIROKO. Harmol induces autophagy and subsequent apoptosis in U251MG human glioma cells through the downregulation of survivin. Oncol Rep 2013; 29:1333-42. [DOI: 10.3892/or.2013.2242] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 11/12/2012] [Indexed: 11/06/2022] Open
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116
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Helgason GV, Holyoake TL, Ryan KM. Role of autophagy in cancer prevention, development and therapy. Essays Biochem 2013; 55:133-51. [PMID: 24070477 DOI: 10.1042/bse0550133] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Autophagy is a process that takes place in all mammalian cells and ensures homoeostasis and quality control. The term autophagy [self (auto)-eating (phagy)] was first introduced in 1963 by Christian de Duve, who discovered the involvement of lysosomes in the autophagy process. Since then, substantial progress has been made in understanding the molecular mechanism and signalling regulation of autophagy and several reviews have been published that comprehensively summarize these findings. The role of autophagy in cancer has received a lot of attention in the last few years and autophagy modulators are now being tested in several clinical trials. In the present chapter we aim to give a brief overview of recent findings regarding the mechanism and key regulators of autophagy and discuss the important physiological role of mammalian autophagy in health and disease. Particular focus is given to the role of autophagy in cancer prevention, development and in response to anticancer therapy. In this regard, we also give an updated list and discuss current clinical trials that aim to modulate autophagy, alone or in combination with radio-, chemo- or targeted therapy, for enhanced anticancer intervention.
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Affiliation(s)
- G Vignir Helgason
- *Paul O'Gorman Leukaemia Research Centre, Institute of Cancer Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 0ZD, U.K
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117
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Pallauf K, Rimbach G. Autophagy, polyphenols and healthy ageing. Ageing Res Rev 2013; 12:237-52. [PMID: 22504405 DOI: 10.1016/j.arr.2012.03.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 03/22/2012] [Accepted: 03/30/2012] [Indexed: 01/25/2023]
Abstract
Autophagy is a lysosomal degradation process that evolved as a starvation response in lower eukaryotes and has gained numerous functions in higher organisms. In animals, autophagy works as a central process in cellular quality control by removing waste or excess proteins and organelles. Impaired autophagy and the age-related decline of this pathway favour the pathogenesis of many diseases that occur especially at higher age such as neurodegenerative diseases and cancer. Caloric restriction (CR) promotes longevity and healthy ageing. Currently, the contributing role of autophagy in the context of CR-induced health benefits is being unravelled. Furthermore recent studies imply that the advantages from polyphenol consumption may be also connected to autophagy induction. In this review, the literature on autophagy regulation by (dietary) polyphenols such as resveratrol, catechin, quercetin, silibinin and curcumin is discussed with a focus on the underlying molecular mechanisms. Special attention is paid to the implications of age-related autophagy decline for diseases and the possibility of dietary countermeasures.
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118
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Bravo-San Pedro JM, Niso-Santano M, Gómez-Sánchez R, Pizarro-Estrella E, Aiastui-Pujana A, Gorostidi A, Climent V, López de Maturana R, Sanchez-Pernaute R, López de Munain A, Fuentes JM, González-Polo RA. The LRRK2 G2019S mutant exacerbates basal autophagy through activation of the MEK/ERK pathway. Cell Mol Life Sci 2013; 70:121-36. [PMID: 22773119 PMCID: PMC11113213 DOI: 10.1007/s00018-012-1061-y] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 05/29/2012] [Accepted: 06/14/2012] [Indexed: 01/16/2023]
Abstract
Mutations in leucine-rich repeat kinase 2 (LRRK2) are a major cause of familial Parkinsonism, and the G2019S mutation of LRRK2 is one of the most prevalent mutations. The deregulation of autophagic processes in nerve cells is thought to be a possible cause of Parkinson's disease (PD). In this study, we observed that G2019S mutant fibroblasts exhibited higher autophagic activity levels than control fibroblasts. Elevated levels of autophagic activity can trigger cell death, and in our study, G2019S mutant cells exhibited increased apoptosis hallmarks compared to control cells. LRRK2 is able to induce the phosphorylation of MAPK/ERK kinases (MEK). The use of 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio]butadiene (U0126), a highly selective inhibitor of MEK1/2, reduced the enhanced autophagy and sensibility observed in G2019S LRRK2 mutation cells. These data suggest that the G2019S mutation induces autophagy via MEK/ERK pathway and that the inhibition of this exacerbated autophagy reduces the sensitivity observed in G2019S mutant cells.
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Affiliation(s)
- José M. Bravo-San Pedro
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Mireia Niso-Santano
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Rubén Gómez-Sánchez
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Elisa Pizarro-Estrella
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Ana Aiastui-Pujana
- Neuroscience Area, Instituto Biodonostia and CIBERNED, 20014 San Sebastián, Spain
| | - Ana Gorostidi
- Neuroscience Area, Instituto Biodonostia and CIBERNED, 20014 San Sebastián, Spain
| | - Vicente Climent
- Departamento de Anatomía y Embriología Humana, Facultad de Medicina, Universidad de Extremadura, 06071 Badajoz, Spain
| | - Rakel López de Maturana
- Laboratorio de Células madre y Neurorreparación, Fundación Inbiomed, 20009 San Sebastián, Spain
| | | | - Adolfo López de Munain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto Biodonostia, Servicio de Neurología, Hospital Donostia, 20014 San Sebastián, Spain
| | - José M. Fuentes
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
| | - Rosa A. González-Polo
- Departamento de Bioquímica y Biología Molecular y Genética, E. Enfermería y T.O., Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universidad de Extremadura, Avda Universidad, s/n, 10003 Cáceres, Spain
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119
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Zhavoronkov A, Smit-McBride Z, Guinan KJ, Litovchenko M, Moskalev A. Potential therapeutic approaches for modulating expression and accumulation of defective lamin A in laminopathies and age-related diseases. J Mol Med (Berl) 2012; 90:1361-89. [PMID: 23090008 PMCID: PMC3506837 DOI: 10.1007/s00109-012-0962-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 09/08/2012] [Accepted: 09/25/2012] [Indexed: 01/28/2023]
Abstract
Scientific understanding of the genetic components of aging has increased in recent years, with several genes being identified as playing roles in the aging process and, potentially, longevity. In particular, genes encoding components of the nuclear lamina in eukaryotes have been increasingly well characterized, owing in part to their clinical significance in age-related diseases. This review focuses on one such gene, which encodes lamin A, a key component of the nuclear lamina. Genetic variation in this gene can give rise to lethal, early-onset diseases known as laminopathies. Here, we analyze the literature and conduct computational analyses of lamin A signaling and intracellular interactions in order to examine potential mechanisms for altering or slowing down aberrant Lamin A expression and/or for restoring the ratio of normal to aberrant lamin A. The ultimate goal of such studies is to ameliorate or combat laminopathies and related diseases of aging, and we provide a discussion of current approaches in this review.
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Affiliation(s)
- Alex Zhavoronkov
- Bioinformatics and Medical Information Technology Laboratory, Center for Pediatric Hematology, Oncology and Immunology, Moscow, 119296 Russia
- The Biogerontology Research Foundation, Reading, UK
| | - Zeljka Smit-McBride
- Department of Ophthalmology and Vision Science, School of Medicine, University of California at Davis, Davis, CA 95616 USA
| | - Kieran J. Guinan
- The Biogerontology Research Foundation, Reading, UK
- BioAtlantis Ltd., Kerry Technology Park, Tralee, County Kerry Ireland
| | - Maria Litovchenko
- Bioinformatics and Medical Information Technology Laboratory, Center for Pediatric Hematology, Oncology and Immunology, Moscow, 119296 Russia
| | - Alexey Moskalev
- The Biogerontology Research Foundation, Reading, UK
- Laboratory of Molecular Radiobiology and Gerontology, Institute of Biology, Komi Science Center of Russian Academy of Sciences, Syktyvkar, 167982 Russia
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120
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Lin ML, Lu YC, Chen HY, Lee CC, Chung JG, Chen SS. Suppressing the formation of lipid raft-associated Rac1/PI3K/Akt signaling complexes by curcumin inhibits SDF-1α-induced invasion of human esophageal carcinoma cells. Mol Carcinog 2012. [PMID: 23192861 DOI: 10.1002/mc.21984] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Stromal cell-derived factor-1α (SDF-1α) is a ligand for C-X-C chemokine receptor type 4 (CXCR4), which contributes to the metastasis of cancer cells by promoting cell migration. Here, we show that the SDF-1α/CXCR4 axis can significantly increase invasion of esophageal carcinoma (EC) cells. We accomplished this by examining the effects of CXCR4 knockdown as well as treatment with a CXCR4-neutralizing antibody and the CXCR4-specific inhibitor AMD3100. Curcumin suppressed SDF-1α-induced cell invasion and matrix metalloproteinase-2 (MMP-2) promoter activity, cell surface localization of CXCR4 at lipid rafts, and lipid raft-associated ras-related C3 botulinum toxin substrate 1 (Rac1)/phosphatidylinositol 3-kinase (PI3K) p85α/Akt signaling. Curcumin inhibited SDF-1α-induced cell invasion by suppressing the Rac1-PI3K signaling complex at lipid rafts but did not abrogate lipid raft formation. We further demonstrate that the attenuation of lipid raft-associated Rac1 activity by curcumin was critical for the inhibition of SDF-1α-induced PI3K/Akt/NF-κB activation, cell surface localization of CXCR4 at lipid rafts, MMP-2 promoter activity, and cell invasion. Collectively, our results indicate that curcumin inhibits SDF-1α-induced EC cell invasion by suppressing the formation of the lipid raft-associated Rac1-PI3K-Akt signaling complex, the localization of CXCR4 with lipid rafts at the cell surface, and MMP-2 promoter activity, likely through the inhibition of Rac1 activity.
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Affiliation(s)
- Meng-Liang Lin
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
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121
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Ghislat G, Patron M, Rizzuto R, Knecht E. Withdrawal of essential amino acids increases autophagy by a pathway involving Ca2+/calmodulin-dependent kinase kinase-β (CaMKK-β). J Biol Chem 2012; 287:38625-36. [PMID: 23027865 DOI: 10.1074/jbc.m112.365767] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Autophagy is the main lysosomal catabolic process that becomes activated under stress conditions, such as amino acid starvation and cytosolic Ca(2+) upload. However, the molecular details on how both conditions control autophagy are still not fully understood. Here we link essential amino acid starvation and Ca(2+) in a signaling pathway to activate autophagy. We show that withdrawal of essential amino acids leads to an increase in cytosolic Ca(2+), arising from both extracellular medium and intracellular stores, which induces the activation of adenosine monophosphate-activated protein kinase (AMPK) via Ca(2+)/calmodulin-dependent kinase kinase-β (CaMKK-β). Furthermore, we show that autophagy induced by amino acid starvation requires AMPK, as this induction is attenuated in its absence. Subsequently, AMPK activates UNC-51-like kinase (ULK1), a mammalian autophagy-initiating kinase, through phosphorylation at Ser-555 in a process that requires CaMKK-β. Finally, the mammalian target of rapamycin complex C1 (mTORC1), a negative regulator of autophagy downstream of AMPK, is inhibited by amino acid starvation in a Ca(2+)-sensitive manner, and CaMKK-β appears to be important for mTORC1 inactivation, especially in the absence of extracellular Ca(2+). All these results highlight that amino acid starvation regulates autophagy in part through an increase in cellular Ca(2+) that activates a CaMKK-β-AMPK pathway and inhibits mTORC1, which results in ULK1 stimulation.
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Affiliation(s)
- Ghita Ghislat
- Laboratorio de Biología Celular, Centro de Investigación Príncipe Felipe and CIBERER, C/Eduardo Primo Yúfera 3, 46012 Valencia, Spain
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122
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Liu N, Tai S, Ding B, Thor RK, Bhuta S, Sun Y, Huang J. Arsenic trioxide synergizes with everolimus (Rad001) to induce cytotoxicity of ovarian cancer cells through increased autophagy and apoptosis. Endocr Relat Cancer 2012; 19:711-23. [PMID: 22919067 DOI: 10.1530/erc-12-0150] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin pathway plays a key role in the tumorigenesis of a variety of human cancers including ovarian cancer. However, inhibitors of this pathway such as Rad001 have not shown therapeutic efficacy as a single agent for this cancer. Arsenic trioxide (ATO) induces an autophagic pathway in ovarian carcinoma cells. We found that ATO can synergize with Rad001 to induce cytotoxicity of ovarian cancer cells. Moreover, we identified synergistic induction of autophagy and apoptosis as the likely underlying mechanism that is responsible for the enhanced cytotoxicity. The enhanced cytotoxicity is accompanied by decreased p-AKT levels as well as upregulation of ATG5-ATG12 conjugate and LC3-2, hallmarks of autophagy. Rad001 and ATO can also synergistically inhibit tumors in a xenograft animal model of ovarian cancer. These results thus identify and validate a novel mechanism to enhance and expand the existing targeted therapeutic agent to treat human ovarian cancer.
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Affiliation(s)
- Nan Liu
- Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, Republic of China
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123
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Possible involvement of the relationship of LRRK2 and autophagy in Parkinson's disease. Biochem Soc Trans 2012; 40:1129-33. [DOI: 10.1042/bst20120095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PD (Parkinson's disease) is a neurodegenerative disorder caused by loss of dopamine-generating cells in the substantia nigra. The implication of genetic factors in the aetiology of PD has an essential importance in our understanding of the development of the disease. Mutations in the LRRK2 (leucine-rich repeat kinase 2) gene cause late-onset PD with a clinical appearance indistinguishable from idiopathic PD. Moreover, LRRK2 has been associated with the process of autophagy regulation. Autophagy is an intracellular catabolic mechanism whereby a cell recycles or degrades damaged proteins and cytoplasmic organelles. In the present paper, we discuss the role of LRRK2 in autophagy, and the importance of this relationship in the development of nigral degeneration in PD.
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124
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Lavallard VJ, Meijer AJ, Codogno P, Gual P. Autophagy, signaling and obesity. Pharmacol Res 2012; 66:513-25. [PMID: 22982482 DOI: 10.1016/j.phrs.2012.09.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 09/04/2012] [Indexed: 12/28/2022]
Abstract
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 the regulation of cellular processes such as lipid metabolism and insulin sensitivity. Important links between the regulation of autophagy and obesity including food intake, adipose tissue development, β cell function, insulin sensitivity and hepatic steatosis exist. This review will provide insight into the current understanding of autophagy, its regulation, and its role in the complications associated with obesity.
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Affiliation(s)
- Vanessa J Lavallard
- INSERM, U1065, Equipe 8 «Complications hépatiques de l'obésité», Nice, France
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125
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Yabu T, Imamura S, Mizusawa N, Touhata K, Yamashita M. Induction of autophagy by amino acid starvation in fish cells. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2012; 14:491-501. [PMID: 22290406 PMCID: PMC3374110 DOI: 10.1007/s10126-012-9432-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 12/21/2011] [Indexed: 05/10/2023]
Abstract
Autophagy is well established as a starvation-induced process in yeast and mammalian cells and tissues. To elucidate the cellular mechanisms induced by starvation in fish, we characterized the induction of autophagy in cultured zebrafish cells under starvation conditions. As an autophagic marker protein, the microtubule-associated protein 1-light chain 3B protein (MAP1-LC3B) was cloned from the fish cells, and its expression and localization were characterized. In zebrafish embryonic (ZE) cells, posttranslational modifications produced two distinct forms of MAP1-LC3B, i.e., a cytosolic form and a membrane-bound form (types I and II, respectively). Immunofluorescence microscopy revealed fluorescently labeled autophagosomes in cells stably transfected with a green fluorescent protein (GFP)–MAP1-LC3B fusion protein and showed that this protein accumulated in punctate dots in a time-dependent manner in response to amino acid starvation. Starvation also induced the degradation of long-lived proteins. Treatment with 3-methyladenine and wortmannin, two class-III inhibitors of phosphoinositide 3-kinase (PI3K), repressed autophagy under starvation conditions, indicating that the PI3K class-III pathway regulates starvation-induced autophagy in fish.
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Affiliation(s)
- Takeshi Yabu
- National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648 Japan
| | - Shintaro Imamura
- National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648 Japan
| | - Nanami Mizusawa
- National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648 Japan
| | - Ken Touhata
- National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648 Japan
| | - Michiaki Yamashita
- National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-8648 Japan
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126
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Wang Y, Qiu Q, Shen JJ, Li DD, Jiang XJ, Si SY, Shao RG, Wang Z. Cardiac glycosides induce autophagy in human non-small cell lung cancer cells through regulation of dual signaling pathways. Int J Biochem Cell Biol 2012; 44:1813-24. [PMID: 22750415 DOI: 10.1016/j.biocel.2012.06.028] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 06/08/2012] [Accepted: 06/19/2012] [Indexed: 12/30/2022]
Abstract
Na(+)/K(+)-ATPase targeted cancer therapy has attracted increasing interests of oncologists in lung cancer field. Although multiple anti-cancer mechanisms of cardiac glycosides as Na(+)/K(+)-ATPase inhibitors are revealed, the role of autophagy and related molecular signaling pathway for the class of compounds in human non-small cell lung cancer (NSCLC) cells has not been systematically examined. We herein investigated the anti-cancer effects of two representative cardiac glycosides, digoxin and ouabain, in A549 and H460 cell lines. Both agents caused significant growth inhibition at nanomolar level. The cardiac glycosides were found to induce moderate G(2)/M arrest but not apoptosis at IC(50) level in the NSCLC cell lines. Moreover, autophagy was markedly induced by both agents, as evidenced by the time- and dose-dependent increase of LC3-II, up-regulation of Atg5 and Beclin1, as well as by the observations through acridine orange staining, transmission electron microscopy and quantification of GFP-LC3 fluorescence. Importantly, AMP-activated protein kinase (AMPK) pathway was activated, resulting in mammalian target of rapamycin (mTOR) deactivation during autophagy induction. Moreover, extracellular-signal-regulated kinase 1/2 (ERK1/2) activation was simultaneously found to be involved in the autophagy regulation. Co-treatment with respective inhibitors or siRNAs could either block the autophagic phenotypes and signals, or significantly increase the cellular viability, indicating the drugs-induced autophagy plays tumor-suppressing role. This work provides first evidence showing that the cardiac glycosides induce autophagy in human NSCLC cells through regulation of both mTOR and ERK1/2 signaling pathways. The autophagy may at least partially account for the growth inhibitory effects of the compounds in human NSCLC cells.
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Affiliation(s)
- Yan Wang
- The Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, PR China
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127
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Zhao Y, Chen H, Shang Z, Jiao B, Yuan B, Sun W, Wang B, Miao M, Huang C. SD118-xanthocillin X (1), a novel marine agent extracted from Penicillium commune, induces autophagy through the inhibition of the MEK/ERK pathway. Mar Drugs 2012; 10:1345-1359. [PMID: 22822377 PMCID: PMC3397444 DOI: 10.3390/md10061345] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 05/29/2012] [Accepted: 05/30/2012] [Indexed: 11/30/2022] Open
Abstract
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.
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Affiliation(s)
- Ying Zhao
- Department of Biochemistry and Molecular Biology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China; (Y.Z.); (H.C.); (B.J.); (B.Y.)
| | - Huan Chen
- Department of Biochemistry and Molecular Biology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China; (Y.Z.); (H.C.); (B.J.); (B.Y.)
| | - Zhuo Shang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;
| | - Binghua Jiao
- Department of Biochemistry and Molecular Biology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China; (Y.Z.); (H.C.); (B.J.); (B.Y.)
| | - Bin Yuan
- Department of Biochemistry and Molecular Biology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China; (Y.Z.); (H.C.); (B.J.); (B.Y.)
| | - Weizhang Sun
- PET (Positron Emission Computed Tomography) Center, General Hospital of Chengdu Military Command, Chengdu, Sichuan 610083, China;
| | - Bingui Wang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;
- Authors to whom correspondence should be addressed; (B.W.); (M.M.); (C.H.); Tel./Fax: +86-532-8289-8553 (B.W.); Tel.: +86-21-8187-0970 (ext. 8006) (M.M.); Fax: +86-21-6533-4344 (M.M.); Tel.: +86-21-8187-0970 (ext. 8020) (C.H.); Fax: +86-21-6533-4344 (C.H.)
| | - Mingyong Miao
- Department of Biochemistry and Molecular Biology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China; (Y.Z.); (H.C.); (B.J.); (B.Y.)
- Authors to whom correspondence should be addressed; (B.W.); (M.M.); (C.H.); Tel./Fax: +86-532-8289-8553 (B.W.); Tel.: +86-21-8187-0970 (ext. 8006) (M.M.); Fax: +86-21-6533-4344 (M.M.); Tel.: +86-21-8187-0970 (ext. 8020) (C.H.); Fax: +86-21-6533-4344 (C.H.)
| | - Caiguo Huang
- Department of Biochemistry and Molecular Biology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China; (Y.Z.); (H.C.); (B.J.); (B.Y.)
- Authors to whom correspondence should be addressed; (B.W.); (M.M.); (C.H.); Tel./Fax: +86-532-8289-8553 (B.W.); Tel.: +86-21-8187-0970 (ext. 8006) (M.M.); Fax: +86-21-6533-4344 (M.M.); Tel.: +86-21-8187-0970 (ext. 8020) (C.H.); Fax: +86-21-6533-4344 (C.H.)
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128
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Botta G, Passaro C, Libertini S, Abagnale A, Barbato S, Maione AS, Hallden G, Beguinot F, Formisano P, Portella G. Inhibition of autophagy enhances the effects of E1A-defective oncolytic adenovirus dl922-947 against glioma cells in vitro and in vivo. Hum Gene Ther 2012; 23:623-34. [PMID: 22475378 DOI: 10.1089/hum.2011.120] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Oncolytic viruses represent a novel therapeutic approach for aggressive tumors, such as glioblastoma multiforme, which are resistant to available treatments. Autophagy has been observed in cells infected with oncolytic viruses; however, its role in cell death/survival is unclear. To elucidate the potential therapeutic use of autophagy modulators in association with viral therapy, we analyzed autophagy induction in human glioma cell lines U373MG and U87MG infected with the oncolytic adenovirus dl922-947. dl922-947 infection triggered an autophagic cellular response, as shown by the development of acidic vesicular organelles, LC3-I→LC3-II conversion, and reduction of p62 levels. However, on infection, the Akt/mTOR/p70s6k pathway, which negatively regulates autophagy, was activated, whereas the ERK1/2 pathway, a positive regulator of autophagy, was inhibited. Accordingly, MEK inhibition by PD98059 sensitized glioma cells to dl922-947 effects, whereas autophagy induction by rapamycin protected cells from dl922-947-induced death. Treatment with two inhibitors of autophagy, chloroquine and 3-methyladenine, increased the cytotoxic effects of dl922-947 in vitro. In vivo, the growth of U87MG-induced xenografts was further reduced by adding chloroquine to the dl922-947 treatment. In conclusion, autophagy acts as a survival response in glioma cells infected with dl922-947, thus suggesting autophagy inhibitors as adjuvant/neoadjuvant drugs in oncolytic virus-based treatments.
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Affiliation(s)
- Ginevra Botta
- Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università Federico II, 80131, Naples, Italy
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129
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Phadwal K, Watson AS, Simon AK. Tightrope act: autophagy in stem cell renewal, differentiation, proliferation, and aging. Cell Mol Life Sci 2012; 70:89-103. [PMID: 22669258 PMCID: PMC3535400 DOI: 10.1007/s00018-012-1032-3] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 05/09/2012] [Accepted: 05/10/2012] [Indexed: 12/19/2022]
Abstract
Autophagy is a constitutive lysosomal catabolic pathway that degrades damaged organelles and protein aggregates. Stem cells are characterized by self-renewal, pluripotency, and quiescence; their long life span, limited capacity to dilute cellular waste and spent organelles due to quiescence, along with their requirement for remodeling in order to differentiate, all suggest that they require autophagy more than other cell types. Here, we review the current literature on the role of autophagy in embryonic and adult stem cells, including hematopoietic, mesenchymal, and neuronal stem cells, highlighting the diverse and contrasting roles autophagy plays in their biology. Furthermore, we review the few studies on stem cells, lysosomal activity, and autophagy. Novel techniques to detect autophagy in primary cells are required to study autophagy in different stem cell types. These will help to elucidate the importance of autophagy in stem cells during transplantation, a promising therapeutic approach for many diseases.
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Affiliation(s)
- Kanchan Phadwal
- BRC Translational Immunology Lab, NIHR, Nuffield Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU UK
| | - Alexander Scarth Watson
- BRC Translational Immunology Lab, NIHR, Nuffield Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU UK
| | - Anna Katharina Simon
- BRC Translational Immunology Lab, NIHR, Nuffield Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU UK
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS UK
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130
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Impaired mitochondrial biogenesis contributes to depletion of functional mitochondria in chronic MPP+ toxicity: dual roles for ERK1/2. Cell Death Dis 2012; 3:e312. [PMID: 22622131 PMCID: PMC3366080 DOI: 10.1038/cddis.2012.46] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The regulation of mitochondrial quality has emerged as a central issue in neurodegeneration, diabetes, and cancer. We utilized repeated low-dose applications of the complex I inhibitor 1-methyl-4-phenylpyridinium (MPP+) over 2 weeks to study cellular responses to chronic mitochondrial stress. Chronic MPP+ triggered depletion of functional mitochondria resulting in diminished capacities for aerobic respiration. Inhibiting autophagy/mitophagy only partially restored mitochondrial content. In contrast, inhibiting activation of extracellular signal-regulated protein kinases conferred complete cytoprotection with full restoration of mitochondrial functional and morphological parameters, enhancing spare respiratory capacity in MPP+ co-treated cells above that of control cells. Reversal of mitochondrial injury occurred when U0126 was added 1 week after MPP+, implicating enhanced repair mechanisms. Chronic MPP+ caused a >90% decrease in complex I subunits, along with decreases in complex III and IV subunits. Decreases in respiratory complex subunits were reversed by co-treatment with U0126, ERK1/2 RNAi or transfection of dominant-negative MEK1, but only partially restored by degradation inhibitors. Chronic MPP+ also suppressed the de novo synthesis of mitochondrial DNA-encoded proteins, accompanied by decreased expression of the mitochondrial transcription factor TFAM. U0126 completely reversed each of these deficits in mitochondrial translation and protein expression. These data indicate a key, limiting role for mitochondrial biogenesis in determining the outcome of injuries associated with elevated mitophagy.
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131
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Abstract
Autophagy is an evolutionarily conserved catabolic pathway that has multiple roles in carcinogenesis and cancer therapy. It can inhibit the initiation of tumorigenesis through limiting cytoplasmic damage, genomic instability and inflammation, and the loss of certain autophagy genes can lead to cancer. Conversely, autophagy can also assist cells in dealing with stressful metabolic environments, thereby promoting cancer cell survival. In fact, some cancers rely on autophagy to survive and progress. Furthermore, tumour cells can exploit autophagy to cope with the cytotoxicity of certain anticancer drugs. By contrast, it appears that certain therapeutics require autophagy for the effective killing of cancer cells. Despite these dichotomies, it is clear that autophagy has an important, if complex, role in cancer. This is further exemplified by the fact that autophagy is connected with major cancer networks, including those driven by p53, mammalian target of rapamycin (mTOR), RAS and glutamine metabolism. In this Commentary, we highlight recent advances in our understanding of the role that autophagy has in cancer and discuss current strategies for targeting autophagy for therapeutic gain.
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Affiliation(s)
- Emma Y Liu
- Tumour Cell Death Laboratory, Beatson Institute for Cancer Research, Garscube Estate, Glasgow, UK
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132
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Chiacchiera F, Grossi V, Cappellari M, Peserico A, Simonatto M, Germani A, Russo S, Moyer MP, Resta N, Murzilli S, Simone C. Blocking p38/ERK crosstalk affects colorectal cancer growth by inducing apoptosis in vitro and in preclinical mouse models. Cancer Lett 2012; 324:98-108. [PMID: 22579651 DOI: 10.1016/j.canlet.2012.05.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 05/02/2012] [Accepted: 05/03/2012] [Indexed: 02/08/2023]
Abstract
We recently demonstrated that p38α is required to maintain colorectal cancer (CRC) metabolism, as its inhibition leads to FoxO3A activation, autophagy, cell death, and tumor growth reduction both in vitro and in vivo. Here we show that inhibition of p38α is followed by TRAIL-mediated activation of caspase-8 and FoxO3A-dependent HER3 upregulation with consequent overactivation of the MEK-ERK1/2 survival pathway. p38α and MEK combined inhibition specifically induces apoptosis by enabling TRAIL signaling propagation through t-Bid and caspase-3, and fosters cell death in CRC cells and preclinical mouse models. Current MEK1-directed pharmacological strategies could thus be exploited, in combination with p38α inhibition, to develop new approaches for CRC treatment.
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Affiliation(s)
- Fulvio Chiacchiera
- Laboratory of Signal-Dependent Transcription, Dept. of Translational Pharmacology, Consorzio Mario Negri Sud, Santa Maria Imbaro (CH) 66030, Italy.
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133
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Autophagy in tumorigenesis and cancer therapy: Dr. Jekyll or Mr. Hyde? Cancer Lett 2012; 323:115-27. [PMID: 22542808 DOI: 10.1016/j.canlet.2012.02.017] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 02/06/2012] [Accepted: 02/16/2012] [Indexed: 12/13/2022]
Abstract
Autophagy is an evolutionarily conserved mechanism for intracellular substance degradation, responsible for the recycling of metabolic substances and the maintenance of intracellular stability. It has early been demonstrated to play a significant role in tumorigenesis, but whether it acts as a promoter or a suppressor during tumorigenesis seems to be context-specific. Moreover, autophagy is also implicated in promoting chemoresistance of cancer cells so as to attenuate therapeutic efficacy of chemotherapy. On the contrary, other reports highlight a tumor-killing role of autophagy during cancer treatment. Herein, this review aims to revisit the key features of autophagy, summarize the seemingly contradictory roles of autophagy during both tumorigenesis and cancer chemotherapy, and evaluate the feasibility of altering the level of cellular autophagy as part of cancer adjuvant treatment.
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134
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Hu P, Lai D, Lu P, Gao J, He H. ERK and Akt signaling pathways are involved in advanced glycation end product-induced autophagy in rat vascular smooth muscle cells. Int J Mol Med 2012; 29:613-8. [PMID: 22293957 PMCID: PMC3573741 DOI: 10.3892/ijmm.2012.891] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 12/29/2011] [Indexed: 12/14/2022] Open
Abstract
Advanced glycation end products (AGEs) play an important role in the proliferation of vascular smooth muscle cells (VSMCs) and accelerate atherosclerosis in diabetic patients. Autophagy, a life-sustaining process, is stimulated in atherosclerotic plaques by oxidized lipids, inflammation and metabolic stress conditions. In our studies, we utilized MTT assays to show that autophagy is involved in AGE-induced proliferation of VSMCs. Furthermore, treatment with AGEs (100 μg/ml) could induce autophagy in a time- and dose-dependent manner in rat aortic VSMCs. These results were further substantiated by electron microscopy and immunofluorescence imaging. Treatment with AGEs activated ERK, JNK and p38/MAPK, but inhibited Akt. Pretreatment with an ERK inhibitor and an Akt activator inhibited AGE-induced autophagy, demonstrating that AGEs induce autophagy in VSMCs through the ERK and Akt signaling pathways. In addition, RNA interference of RAGE decreased autophagy, indicating that RAGE is pivotal in the process of AGE-induced autophagy. Therefore, AGE-induced autophagy contributes to the process of AGE-induced proliferation of VSMCs, which is related to atherosclerosis in diabetes.
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Affiliation(s)
- Pengfei Hu
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, Zhejiang Province, PR China
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135
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Zeng Y, Yang X, Wang J, Fan J, Kong Q, Yu X. Aristolochic acid I induced autophagy extenuates cell apoptosis via ERK 1/2 pathway in renal tubular epithelial cells. PLoS One 2012; 7:e30312. [PMID: 22276178 PMCID: PMC3262826 DOI: 10.1371/journal.pone.0030312] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 12/13/2011] [Indexed: 12/22/2022] Open
Abstract
Autophagy is a lysosomal degradation pathway that is essential for cell survival and tissue homeostasis. However, limited information is available about autophagy in aristolochic acid (AA) nephropathy. In this study, we investigated the role of autophagy and related signaling pathway during progression of AAI-induced injury to renal tubular epithelial cells (NRK52E cells). The results showed that autophagy in NRK52E cells was detected as early as 3–6 hrs after low dose of AAI (10 µM) exposure as indicated by an up-regulated expression of LC3-II and Beclin 1 proteins. The appearance of AAI-induced punctated staining of autophagosome-associated LC3-II upon GFP-LC3 transfection in NRK52E cells provided further evidence for autophagy. However, cell apoptosis was not detected until 12 hrs after AAI treatment. Blockade of autophagy with Wortmannin or 3-Methyladenine (two inhibitors of phosphoinositede 3-kinases) or small-interfering RNA knockdown of Beclin 1 or Atg7 sensitized the tubular cells to apoptosis. Treatment of NRK52E cells with AAI caused a time-dependent increase in extracellular signal-regulated kinase 1 and 2 (ERK1/2) activity, but not c-Jun N-terminal kinase (JNK) and p38. Pharmacological inhibition of ERK1/2 phosphorylation with U0126 resulted in a decreased AAI-induced autophagy that was accompanied by an increased apoptosis. Taken together, our study demonstrated for the first time that autophagy occurred earlier than apoptosis during AAI-induced tubular epithelial cell injury. Autophagy induced by AAI via ERK1/2 pathway might attenuate apoptosis, which may provide a protective mechanism for cell survival under AAI-induced pathological condition.
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Affiliation(s)
- Youjia Zeng
- Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Key Laboratory of Nephrology, Ministry of Health, Guangzhou, Guangdong, China
| | - Xiao Yang
- Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Key Laboratory of Nephrology, Ministry of Health, Guangzhou, Guangdong, China
- * E-mail:
| | - Juan Wang
- Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Key Laboratory of Nephrology, Ministry of Health, Guangzhou, Guangdong, China
| | - Jinjin Fan
- Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Key Laboratory of Nephrology, Ministry of Health, Guangzhou, Guangdong, China
| | - Qingyu Kong
- Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Key Laboratory of Nephrology, Ministry of Health, Guangzhou, Guangdong, China
| | - Xueqing Yu
- Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Key Laboratory of Nephrology, Ministry of Health, Guangzhou, Guangdong, China
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136
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para-Phenylenediamine-induced autophagy in human uroepithelial cell line mediated mutant p53 and activation of ERK signaling pathway. Toxicol In Vitro 2011; 25:1630-7. [DOI: 10.1016/j.tiv.2011.06.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Revised: 06/08/2011] [Accepted: 06/16/2011] [Indexed: 12/22/2022]
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137
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The KDEL receptor induces autophagy to promote the clearance of neurodegenerative disease-related proteins. Neuroscience 2011; 190:43-55. [DOI: 10.1016/j.neuroscience.2011.06.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/10/2011] [Accepted: 06/01/2011] [Indexed: 12/14/2022]
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138
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Fu L, Balasubramanian M, Shan J, Dudenhausen EE, Kilberg MS. Auto-activation of c-JUN gene by amino acid deprivation of hepatocellular carcinoma cells reveals a novel c-JUN-mediated signaling pathway. J Biol Chem 2011; 286:36724-38. [PMID: 21862593 DOI: 10.1074/jbc.m111.277673] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mammalian cells respond to protein or amino acid (AA) limitation by activating a number of signaling pathways, collectively referred to as the AA response (AAR), that modulate a range of cellular functions, including transcriptional induction of target genes. This study demonstrates that in hepatocellular carcinoma cells, expression of c-JUN, JUN-B, c-FOS, and FOS-B was induced by the AAR, whereas JUN-D, FRA-1, and FRA-2 were not. Of the four activated FOS/JUN members, c-JUN made the largest contribution to the induction of several known AAR target genes. For several human liver, prostate, and ovarian cell lines, the AAR-induced increase in c-JUN expression was greater in transformed cells compared with nontransformed counterparts, an effect independent of cell growth rate. Thus far, the best characterized AA-responsive genes are all transcriptionally activated by ATF4, but the AAR-dependent induction of c-JUN transcription was ATF4-independent. The increased expression of c-JUN was dependent on ATF2 and on activation of the MEK-ERK and JNK arms of the MAPK signaling pathways. Formation of c-JUN-ATF2-activated heterodimers was increased after AA limitation, and c-JUN or ATF2 knockdown suppressed the induction of c-JUN and other AAR target genes. AA deprivation triggers a feed-forward process that involves phosphorylation of existing c-JUN protein by JNK and subsequent auto-activation of the c-JUN gene by recruitment of c-JUN and ATF2 to two AP-1 sites within the proximal promoter. The results document the novel observation that AP-1 sequences within the c-JUN gene can function as transcriptional amino acid-response elements.
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Affiliation(s)
- Lingchen Fu
- Department of Biochemistry and Molecular Biology, Shands Cancer Center, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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139
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Is autophagy rather than apoptosis the regression driver in imatinib-treated gastrointestinal stromal tumors? Transl Oncol 2011; 1:177-86. [PMID: 19043528 DOI: 10.1593/tlo.08157] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 09/04/2008] [Accepted: 09/08/2008] [Indexed: 12/23/2022] Open
Abstract
Although apoptosis (programmed cell death type I) is more frequently reported in the literature in imatinib-treated gastrointestinal stromal tumor (GIST) cell lines,morphological features consistent with autophagic changes aremore often encountered in surgical specimens of treated patients. Autophagy (programmed cell death type II) is highly regulated by a tumor-suppressor mechanism that mainly involves the genes beclin1, PI3KIII, and bcl2. Being our material not suitable for electron microscopy analysis (not paraformaldehyde-glutaraldehyde-fixed), we evaluated the morphological, biochemical, and immunophenotypical profiles expected to be related to autophagy and apoptosis in a series of surgically resected samples taken from 11 imatinib-treated patients with molecularly characterized GISTs. The samples were examined for imatinib-induced morphological changes, the presence/interactions of the autophagic-related proteins (beclin1, PI3KIII, bcl2, and LC3-II) and the presence of apoptosis-related proteins (caspase 3, caspase 7, and lamin A/C) by means ofWestern blot analysis and coimmunoprecipitation, complemented by immunohistochemistry. We also studied samples of two untreated GISTs used as controls. Sampling areas with different residual cellularity scores fromboth the imatinib-treated and untreated patients showed biochemical and immunohistochemical evidence of high levels of proautophagy beclin1/PI3KIII and low levels of antiautophagy beclin1/bcl2 complexes, together with the presence of LC3-II detected by Western blot analysis, thus supporting the presence of autophagy. There was no expression of cleaved/activated caspase 3 or 7 or cleaved lamin A/C. Our descriptive results support the idea that GISTs activate autophagy rather than apoptosis in response to imatinib treatment and that their molecular makeup includes fingerprints of autophagy.
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140
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Abstract
Autophagy is a degradative pathway that involves delivery of cytoplasmic components, including proteins, organelles, and invaded microbes to the lysosome for digestion. Autophagy is implicated in the pathology of various human diseases. The association of autophagy to inflammatory bowel diseases is consistent with recent discoveries of its role in immunity. A complex of signaling pathways control the induction of autophagy in different cellular contexts. Reactive oxygen species (ROS) are highly reactive oxygen free radicals or non-radical molecules that are generated by multiple mechanisms in cells, with the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and mitochondria as major cellular sources. These ROS are important signaling molecules that regulate many signal-transduction pathways and play critical roles in cell survival, death, and immune defenses. ROS were recently shown to activate starvation-induced autophagy, antibacterial autophagy, and autophagic cell death. Current findings implicate ROS in the regulation of autophagy through distinct mechanisms, depending on cell types and stimulation conditions. Conversely, autophagy can also suppress ROS production. Understanding the mechanisms behind ROS-induced autophagy will provide significant therapeutic implications for related diseases.
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Affiliation(s)
- Ju Huang
- Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada
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141
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Morselli E, Galluzzi L, Kepp O, Mariño G, Michaud M, Vitale I, Maiuri MC, Kroemer G. Oncosuppressive functions of autophagy. Antioxid Redox Signal 2011; 14:2251-69. [PMID: 20712403 DOI: 10.1089/ars.2010.3478] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Macroautophagy (herein referred to as autophagy) constitutes a phylogenetically old mechanism leading to the lysosomal degradation of cytoplasmic structures. At baseline levels, autophagy exerts homeostatic functions by ensuring the turnover of potentially harmful organelles and long-lived aggregate-prone proteins. Moreover, the autophagic flow can be dramatically upregulated in response to a plethora of stressful conditions, including glucose, amino acid, oxygen, or growth factor deprivation, accumulation of unfolded proteins in the endoplasmic reticulum, and invasion by intracellular pathogens. In some experimental settings, stress-induced autophagy has been shown to contribute to programmed cell death. Nevertheless, autophagy most often confers cytoprotection by providing cells with new metabolic substrates or by ridding them of noxious intracellular entities including protein aggregates and invading organisms. Thus, autophagy has been implicated in an ever-increasing number of human diseases including cancer. Autophagy inhibition accelerates the demise of tumor cells that are subjected to chemo- or radiotherapy, thereby constituting an interesting target for the development of anticancer strategies. However, several oncosuppressor proteins and oncoproteins have been recently shown to stimulate and inhibit the autophagic flow, respectively, suggesting that autophagy exerts bona fide tumor-suppressive functions. In this review, we will discuss the mechanisms by which autophagy may prevent oncogenesis.
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142
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Chen SY, Chiu LY, Maa MC, Wang JS, Chien CL, Lin WW. zVAD-induced autophagic cell death requires c-Src-dependent ERK and JNK activation and reactive oxygen species generation. Autophagy 2011; 7:217-28. [PMID: 21127402 DOI: 10.4161/auto.7.2.14212] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The treatment of L929 fibrosarcoma cells with zVAD has been shown to induce necroptosis. However, whether autophagy is involved or not in this event remains controversial. In this study, we re-examined the role of autophagy in zVAD-induced cell death in L929 cells and further elucidated the signaling pathways triggered by caspase inhibition and contributing to autophagic death. First, we found that zVAD can stimulate LC3-II formation, autophagosome and autolysosome formation, and ROS accumulation. Antioxidants, beclin 1 or Atg5 silencing, and class III PtdIns3K inhibitors all effectively blocked ROS production and cell death, suggesting ROS accumulation downstream of autophagy contributes to cell necrosis. zVAD also stimulated PARP activation, and the PARP inhibitor DPQ can reduce zVAD-induced cell death, but did not affect ROS production, suggesting the increased ROS leads to PARP activation and cell death. Notably, our data also indicated the involvement of Src-dependent JNK and ERK in zVAD-induced ROS production and autophagic death. We found caspase 8 is associated with c-Src at the resting state, and upon zVAD treatment this association was decreased and accompanied by c-Src activation. In conclusion, we confirm the autophagic death in zVAD-treated L929 cells, and define a new molecular pathway in which Src-dependent ERK and JNK activation can link a signal from caspase inhibition to autophagy, which in turn induce ROS production and PARP activation, eventually leading to necroptosis. Thus, in addition to initiating proteolytic activity for cell apoptosis, inactivated caspase 8 also functions as a signaling molecule for autophagic death.
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Affiliation(s)
- Szu-ying Chen
- Department of Pharmacology, College of Medicine, National Taiwan University, Taiwan, Taiwan
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143
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Lock R, Roy S, Kenific CM, Su JS, Salas E, Ronen SM, Debnath J. Autophagy facilitates glycolysis during Ras-mediated oncogenic transformation. Mol Biol Cell 2011; 22:165-78. [PMID: 21119005 PMCID: PMC3020913 DOI: 10.1091/mbc.e10-06-0500] [Citation(s) in RCA: 365] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2010] [Revised: 10/22/2010] [Accepted: 11/08/2010] [Indexed: 12/13/2022] Open
Abstract
The protumorigenic functions for autophagy are largely attributed to its ability to promote cancer cell survival in response to diverse stresses. Here we demonstrate an unexpected connection between autophagy and glucose metabolism that facilitates adhesion-independent transformation driven by a strong oncogenic insult-mutationally active Ras. In cells ectopically expressing oncogenic H-Ras as well as human cancer cell lines harboring endogenous K-Ras mutations, autophagy is induced following extracellular matrix detachment. Inhibiting autophagy due to the genetic deletion or RNA interference-mediated depletion of multiple autophagy regulators attenuates Ras-mediated adhesion-independent transformation and proliferation as well as reduces glycolytic capacity. Furthermore, in contrast to autophagy-competent cells, both proliferation and transformation in autophagy-deficient cells expressing oncogenic Ras are insensitive to reductions in glucose availability. Overall, increased glycolysis in autophagy-competent cells facilitates Ras-mediated adhesion-independent transformation, suggesting a unique mechanism by which autophagy may promote Ras-driven tumor growth in specific metabolic contexts.
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Affiliation(s)
- Rebecca Lock
- Department of Pathology, University of California, San Francisco
- Biomedical Sciences Graduate Program, University of California, San Francisco
| | - Srirupa Roy
- Department of Pathology, University of California, San Francisco
| | - Candia M. Kenific
- Department of Pathology, University of California, San Francisco
- Biomedical Sciences Graduate Program, University of California, San Francisco
| | - Judy S. Su
- Department of Radiology and Biomedical Imaging, University of California, San Francisco
| | - Eduardo Salas
- Department of Pathology, University of California, San Francisco
| | - Sabrina M. Ronen
- Department of Radiology and Biomedical Imaging, University of California, San Francisco
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143
| | - Jayanta Debnath
- Department of Pathology, University of California, San Francisco
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143
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144
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Abe A, Yamada H, Moriya S, Miyazawa K. The .BETA.-Carboline Alkaloid Harmol Induces Cell Death via Autophagy but Not Apoptosis in Human Non-small Cell Lung Cancer A549 Cells. Biol Pharm Bull 2011; 34:1264-72. [DOI: 10.1248/bpb.34.1264] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Akihisa Abe
- Department of Biochemistry, Tokyo Medical University
| | - Hiroyuki Yamada
- Bacteriology Division, Mycobacterium Reference Center, Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association (JATA)
| | - Shota Moriya
- Department of Biochemistry, Tokyo Medical University
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145
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Overmeyer JH, Maltese WA. Death pathways triggered by activated Ras in cancer cells. Front Biosci (Landmark Ed) 2011; 16:1693-713. [PMID: 21196257 DOI: 10.2741/3814] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ras GTPases are best known for their ability to serve as molecular switches regulating cell growth, differentiation and survival. Gene mutations that result in expression of constitutively active forms of Ras have been linked to oncogenesis in animal models and humans. However, over the past two decades, evidence has gradually accumulated to support a paradoxical role for Ras proteins in the initiation of cell death pathways. In this review we survey the literature pointing to the ability of activated Ras to promote cell death under conditions where cancer cells encounter apoptotic stimuli or Ras is ectopically expressed. In some of these cases Ras acts through known effectors and well defined apoptotic death pathways. However, in other cases it appears that Ras operates by triggering novel non-apoptotic death mechanisms that are just beginning to be characterized. Understanding these mechanisms and the factors that go into changing the nature of Ras signaling from pro-survival to pro-death could set the stage for development of novel therapeutic approaches aimed at manipulating pro-death Ras signaling pathways in cancer.
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Affiliation(s)
- Jean H Overmeyer
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine, Toledo, Ohio 43614, USA
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146
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Liu JJ, Lin M, Yu JY, Liu B, Bao JK. Targeting apoptotic and autophagic pathways for cancer therapeutics. Cancer Lett 2011; 300:105-14. [DOI: 10.1016/j.canlet.2010.10.001] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2010] [Revised: 09/07/2010] [Accepted: 10/04/2010] [Indexed: 12/19/2022]
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147
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Wu CY, Yan J, Yang YF, Xiao FJ, Li QF, Zhang QW, Wang LS, Guo XZ, Wang H. Overexpression of KAI1 induces autophagy and increases MiaPaCa-2 cell survival through the phosphorylation of extracellular signal-regulated kinases. Biochem Biophys Res Commun 2010; 404:802-8. [PMID: 21168384 DOI: 10.1016/j.bbrc.2010.12.063] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 12/10/2010] [Indexed: 12/19/2022]
Abstract
KAI1, a metastasis-suppressor gene belonging to the tetraspanin family, is known to inhibit cancer metastasis without affecting the primary tumorigenicity by inhibiting the epidermal growth factor (EGF) signaling pathway. Recent studies have shown that hypoxic conditions of solid tumors induce high-level autophagy and KAI1 expression. However, the relationship between autophagy and KAI1 remains unclear. By using transmission electron microscopy, confocal microscopy, and Western blotting, we found that KAI1 can induce autophagy in a dose- and time-dependent manner in the human pancreatic cell line MiaPaCa-2. KAI1-induced autophagy was confirmed by the expression of autophagy-related proteins LC3 and Beclin 1. KAI1 induces autophagy through phosphorylation of extracellular signal-related kinases rather than that of AKT. KAI1-induced autophagy protects MiaPaCa-2 cells from apoptosis and proliferation inhibition partially through the downregulation of poly [adenosine diphosphate (ADP)-ribose] polymerase (PARP) cleavage and caspase-3 activation.
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Affiliation(s)
- Chun-Yan Wu
- State Key Laboratory of Cancer Biology and Institute of Digestive Diseases, Xijing Hospital of Digestive Disease, Fourth Military Medical University, Xi'an 710032, PR China
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148
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Rikiishi H. Possible role of autophagy in the treatment of pancreatic cancer with histone deacetylase inhibitors. Cancers (Basel) 2010; 2:2026-43. [PMID: 24281216 PMCID: PMC3840459 DOI: 10.3390/cancers2042026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 11/09/2010] [Accepted: 11/22/2010] [Indexed: 12/15/2022] Open
Abstract
Pancreatic cancer is a lethal disease and notoriously difficult to treat. Only a small proportion is curative by surgical resection, whilst standard chemotherapy for patients with advanced disease has only a modest effect with substantial toxicity. Clearly there is a need for the continual development of novel therapeutic agents to improve the current situation. Currently, there is a bulk of data indicating the important function of autophagy in cancer. While genetic evidence indicates that autophagy functions as a tumor suppressor, it is also apparent that autophagy can promote the survival of established tumors under stress conditions and in response to chemotherapy. This review provides a spectrum of potential pharmacological agents and autophagic approaches to enhance cell killing in pancreatic cancer.
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Affiliation(s)
- Hidemi Rikiishi
- Department of Microbiology and Immunology, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
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149
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Ravikumar B, Sarkar S, Davies JE, Futter M, Garcia-Arencibia M, Green-Thompson ZW, Jimenez-Sanchez M, Korolchuk VI, Lichtenberg M, Luo S, Massey DCO, Menzies FM, Moreau K, Narayanan U, Renna M, Siddiqi FH, Underwood BR, Winslow AR, Rubinsztein DC. Regulation of mammalian autophagy in physiology and pathophysiology. Physiol Rev 2010; 90:1383-435. [PMID: 20959619 DOI: 10.1152/physrev.00030.2009] [Citation(s) in RCA: 1343] [Impact Index Per Article: 95.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
(Macro)autophagy is a bulk degradation process that mediates the clearance of long-lived proteins and organelles. Autophagy is initiated by double-membraned structures, which engulf portions of cytoplasm. The resulting autophagosomes ultimately fuse with lysosomes, where their contents are degraded. Although the term autophagy was first used in 1963, the field has witnessed dramatic growth in the last 5 years, partly as a consequence of the discovery of key components of its cellular machinery. In this review we focus on mammalian autophagy, and we give an overview of the understanding of its machinery and the signaling cascades that regulate it. As recent studies have also shown that autophagy is critical in a range of normal human physiological processes, and defective autophagy is associated with diverse diseases, including neurodegeneration, lysosomal storage diseases, cancers, and Crohn's disease, we discuss the roles of autophagy in health and disease, while trying to critically evaluate if the coincidence between autophagy and these conditions is causal or an epiphenomenon. Finally, we consider the possibility of autophagy upregulation as a therapeutic approach for various conditions.
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Affiliation(s)
- Brinda Ravikumar
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Addenbrooke’s Hospital, Cambridge, United Kingdom
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150
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Eum KH, Lee M. Crosstalk between autophagy and apoptosis in the regulation of paclitaxel-induced cell death in v-Ha-ras-transformed fibroblasts. Mol Cell Biochem 2010; 348:61-8. [DOI: 10.1007/s11010-010-0638-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 10/28/2010] [Indexed: 12/19/2022]
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