1
|
Yao J, Jia L, Khan N, Lin C, Mitter SK, Boulton ME, Dunaief JL, Klionsky DJ, Guan JL, Thompson DA, Zacks DN. Deletion of autophagy inducer RB1CC1 results in degeneration of the retinal pigment epithelium. Autophagy 2016; 11:939-53. [PMID: 26075877 DOI: 10.1080/15548627.2015.1041699] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Autophagy regulates cellular homeostasis and response to environmental stress. Within the retinal pigment epithelium (RPE) of the eye, the level of autophagy can change with both age and disease. The purpose of this study is to determine the relationship between reduced autophagy and age-related degeneration of the RPE. The gene encoding RB1CC1/FIP200 (RB1-inducible coiled-coil 1), a protein essential for induction of autophagy, was selectively knocked out in the RPE by crossing Best1-Cre mice with mice in which the Rb1cc1 gene was flanked with Lox-P sites (Rb1cc1(flox/flox)). Ex vivo and in vivo analyses, including western blot, immunohistochemistry, transmission electron microscopy, fundus photography, optical coherence tomography, fluorescein angiography, and electroretinography were performed to assess the structure and function of the retina as a function of age. Deletion of Rb1cc1 resulted in multiple autophagy defects within the RPE including decreased conversion of LC3-I to LC3-II, accumulation of autophagy-targeted precursors, and increased numbers of mitochondria. Age-dependent degeneration of the RPE occurred, with formation of atrophic patches, subretinal migration of activated microglial cells, subRPE deposition of inflammatory and oxidatively damaged proteins, subretinal drusenoid deposits, and occasional foci of choroidal neovascularization. There was secondary loss of photoreceptors overlying the degenerated RPE and reduction in the electroretinogram. These observations are consistent with a critical role of autophagy in the maintenance of normal homeostasis in the aging RPE, and indicate that disruption of autophagy leads to retinal phenotypes associated with age-related degeneration.
Collapse
Key Words
- AMD, age-related macular degeneration
- ANOVA, analysis of variance
- Bru, Bruch's membrane
- CKO, conditional knockout
- CTSD, cathepsin D
- ERG, electroretinogram
- FIP200
- GCL, ganglion cell layer
- INL, inner nuclear layer
- IS, inner segment
- LAP, LC3-associated phagocytosis
- MTOR, mechanistic target of rapamycin
- OCT, optical coherence tomography
- ONL, outer nuclear layer
- OS, outer segment
- PBS, phosphate-buffered saline
- POS, photoreceptor outer segments
- RB1CC1, RB1-inducible coiled-coil 1
- RPE, retinal pigment epithelium
- age-related macular degeneration
- photoreceptor
- retina
- retinal pigment epithelium
- siRNA, small interfering ribonucleic acid.
Collapse
Affiliation(s)
- Jingyu Yao
- a Department of Ophthalmology and Visual Sciences ; University of Michigan ; Ann Arbor , MI USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
2
|
Abstract
Cocaine abuse leads to neuroinflammation, which, in turn, contributes to the pathogenesis of neurodegeneration associated with advanced HIV-1 infection. Autophagy plays important roles in both innate and adaptive immune responses. However, the possible functional link between cocaine and autophagy has not been explored before. Herein, we demonstrate that cocaine exposure induced autophagy in both BV-2 and primary rat microglial cells as demonstrated by a dose- and time-dependent induction of autophagy-signature proteins such as BECN1/Beclin 1, ATG5, and MAP1LC3B. These findings were validated wherein cocaine treatment of BV-2 cells resulted in increased formation of puncta in cells expressing either endogenous MAP1LC3B or overexpressing GFP-MAP1LC3B. Specificity of cocaine-induced autophagy was confirmed by treating cells with inhibitors of autophagy (3-MA and wortmannin). Intriguingly, cocaine-mediated induction of autophagy involved upstream activation of 2 ER stress pathways (EIF2AK3- and ERN1-dependent), as evidenced by the ability of the ER stress inhibitor salubrinal to ameliorate cocaine-induced autophagy. In vivo validation of these findings demonstrated increased expression of BECN1, ATG5, and MAP1LC3B-II proteins in cocaine-treated mouse brains compared to untreated animals. Increased autophagy contributes to cocaine-mediated activation of microglia since pretreatment of cells with wortmannin resulted in decreased expression and release of inflammatory factors (TNF, IL1B, IL6, and CCL2) in microglial cells. Taken together, our findings suggest that cocaine exposure results in induction of autophagy that is closely linked with neuroinflammation. Targeting autophagic proteins could thus be considered as a therapeutic strategy for the treatment of cocaine-related neuroinflammation diseases.
Collapse
Key Words
- 3-MA, 3-methyladenine
- ATF6, activating transcription factor 6
- ATG5, autophagy-related 5
- BCL2, B-cell CLL/lymphoma 2
- BECN1
- BECN1, Beclin 1, autophagy related
- Baf1, bafilomycin A1
- CCL2, chemokine (C-C motif) ligand 2
- DAPI: 4, 6-diamidino-2-phenylindole, dihydrochloride
- DDIT3, DNA-damage-inducible transcript 3
- EGFP, enhanced green fluorescent protein
- EIF2AK3, eukaryotic translation initiation factor 2-α kinase 3
- EIF2S1, eukaryotic translation initiation factor 2, subunit 1 α, 35kDa
- ER stress
- ER, endoplasmic reticulum
- ERN1, endoplasmic reticulum to nucleus signaling 1
- HIV, human immunodeficiency virus
- IL1B, interleukin 1, β
- IL6, interleukin 6
- MAP1LC3B
- MAP1LC3B, microtubule-associated protein 1 light chain 3
- METH, methamphetamine
- MTOR, mechanistic target of rapamycin
- NFKB1, nuclear factor of kappa light polypeptide gene enhancer in B-cells 1
- PBN, N-tert-butyl-α-phenylnitrone
- PPP1R3A, protein phosphatase 1, regulatory subunit 3A
- PtdIns3K, class III phosphatidylinositol 3-kinase
- ROS, reactive oxygen species
- RPS6, ribosomal protein S6
- TLR4, toll-like receptor 4
- TNF, tumor necrosis factor
- autophagy
- cocaine
- microglial cells
- neuroinflammation
- rPMCs, rat primary microglial cells
- wort, wortmannin
Collapse
Affiliation(s)
- Ming-Lei Guo
- a Department of Pharmacology and Experimental Neuroscience; Nebraska Medical Center; University of Nebraska Medical Center ; Omaha , NE , USA
| | | | | | | | | | | | | |
Collapse
|
3
|
Abstract
Autophagy and senescence have been described as central features of cell biology, but the interplay between these mechanisms remains obscure. Using a therapeutically relevant model of DNA damage-induced senescence in human glioma cells, we demonstrated that acute treatment with temozolomide induces DNA damage, a transitory activation of PRKAA/AMPK-ULK1 and MAPK14/p38 and the sustained inhibition of AKT-MTOR. This produced a transient induction of autophagy, which was followed by senescence. However, at the single cell level, this coordinated transition was not observed, and autophagy and senescence were triggered in a very heterogeneous manner. Indeed, at a population level, autophagy was highly negatively correlated with senescence markers, while in single cells this correlation did not exist. The inhibition of autophagy triggered apoptosis and decreased senescence, while its activation increased temozolomide-induced senescence, showing that DNA damage-induced autophagy acts by suppressing apoptosis.
Collapse
Key Words
- 3MA, 3-methyladenine
- AMP-activated
- AO, acridine orange
- BafA1, bafilomycin A1
- CDKN1A/p21, cyclin-dependent kinase inhibitor 1A (p21 Cip1)
- CPD, cumulative population doubling
- DDR, DNA damage response
- DFM, drug-free medium
- DNA damage
- H2AFX, H2A histone family
- MAP1LC3A/LC3, microtubule-associated protein 1 light chain 3 α
- MTOR, mechanistic target of rapamycin
- MTORC1, MTOR complex 1
- NA, nuclear area
- NMA, nuclear morphometric analysis
- PRKAA/AMPKα, protein kinase
- RAPA, rapamycin
- RPTOR/RAPTOR, regulatory-associated protein of MTOR
- SA-β-gal, senescence associated β-galactosidase assay
- SQSTM1/p62, sequestosome 1
- TMZ, temozolomide
- autophagy
- cP1-4, cellular population 1 to 4
- complex 1
- member X
- nP1–5, nuclear population 1 to 5
- senescence
- single cell
- temozolomide
Collapse
|
4
|
Filippi-Chiela EC, Bueno e Silva MM, Thomé MP, Lenz G. Single-cell analysis challenges the connection between autophagy and senescence induced by DNA damage. Autophagy. 2015;11:1099-1113. [PMID: 25701485 DOI: 10.0180/15548627.2015.1009795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Autophagy and senescence have been described as central features of cell biology, but the interplay between these mechanisms remains obscure. Using a therapeutically relevant model of DNA damage-induced senescence in human glioma cells, we demonstrated that acute treatment with temozolomide induces DNA damage, a transitory activation of PRKAA/AMPK-ULK1 and MAPK14/p38 and the sustained inhibition of AKT-MTOR. This produced a transient induction of autophagy, which was followed by senescence. However, at the single cell level, this coordinated transition was not observed, and autophagy and senescence were triggered in a very heterogeneous manner. Indeed, at a population level, autophagy was highly negatively correlated with senescence markers, while in single cells this correlation did not exist. The inhibition of autophagy triggered apoptosis and decreased senescence, while its activation increased temozolomide-induced senescence, showing that DNA damage-induced autophagy acts by suppressing apoptosis.
Collapse
Key Words
- 3MA, 3-methyladenine
- AMP-activated
- AO, acridine orange
- BafA1, bafilomycin A1
- CDKN1A/p21, cyclin-dependent kinase inhibitor 1A (p21 Cip1)
- CPD, cumulative population doubling
- DDR, DNA damage response
- DFM, drug-free medium
- DNA damage
- H2AFX, H2A histone family
- MAP1LC3A/LC3, microtubule-associated protein 1 light chain 3 α
- MTOR, mechanistic target of rapamycin
- MTORC1, MTOR complex 1
- NA, nuclear area
- NMA, nuclear morphometric analysis
- PRKAA/AMPKα, protein kinase
- RAPA, rapamycin
- RPTOR/RAPTOR, regulatory-associated protein of MTOR
- SA-β-gal, senescence associated β-galactosidase assay
- SQSTM1/p62, sequestosome 1
- TMZ, temozolomide
- autophagy
- cP1-4, cellular population 1 to 4
- complex 1
- member X
- nP1–5, nuclear population 1 to 5
- senescence
- single cell
- temozolomide
Collapse
|
5
|
Kanamori H, Takemura G, Goto K, Tsujimoto A, Mikami A, Ogino A, Watanabe T, Morishita K, Okada H, Kawasaki M, Seishima M, Minatoguchi S. Autophagic adaptations in diabetic cardiomyopathy differ between type 1 and type 2 diabetes. Autophagy 2016; 11:1146-60. [PMID: 26042865 DOI: 10.1080/15548627.2015.1051295] [Citation(s) in RCA: 173] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Little is known about the association between autophagy and diabetic cardiomyopathy. Also unknown are possible distinguishing features of cardiac autophagy in type 1 and type 2 diabetes. In hearts from streptozotocin-induced type 1 diabetic mice, diastolic function was impaired, though autophagic activity was significantly increased, as evidenced by increases in microtubule-associated protein 1 light chain 3/LC3 and LC3-II/-I ratios, SQSTM1/p62 (sequestosome 1) and CTSD (cathepsin D), and by the abundance of autophagic vacuoles and lysosomes detected electron-microscopically. AMP-activated protein kinase (AMPK) was activated and ATP content was reduced in type 1 diabetic hearts. Treatment with chloroquine, an autophagy inhibitor, worsened cardiac performance in type 1 diabetes. In addition, hearts from db/db type 2 diabetic model mice exhibited poorer diastolic function than control hearts from db/+ mice. However, levels of LC3-II, SQSTM1 and phosphorylated MTOR (mechanistic target of rapamycin) were increased, but CTSD was decreased and very few lysosomes were detected ultrastructurally, despite the abundance of autophagic vacuoles. AMPK activity was suppressed and ATP content was reduced in type 2 diabetic hearts. These findings suggest the autophagic process is suppressed at the final digestion step in type 2 diabetic hearts. Resveratrol, an autophagy enhancer, mitigated diastolic dysfunction, while chloroquine had the opposite effects in type 2 diabetic hearts. Autophagy in the heart is enhanced in type 1 diabetes, but is suppressed in type 2 diabetes. This difference provides important insight into the pathophysiology of diabetic cardiomyopathy, which is essential for the development of new treatment strategies.
Collapse
Key Words
- AMP-activated protein kinase
- AMPK, AMP-activated protein kinase
- CTSD, cathepsin D
- DM, diabetes mellitus
- GFP, green fluorescent protein
- HBA1c, glycated hemoglobin α 1
- LV, left ventricular
- MAP1LC3/LC3, microtubule-associated protein 1 light chain 3
- MTOR, mechanistic target of rapamycin
- Mn-SOD, superoxide dismutase 2, mitochondrial
- SIRT1, sirtuin 1
- SQSTM1/p62, sequestosome 1
- STZ, streptozotocin
- autophagy
- cardiomyopathy
- chloroquine
- diabetes mellitus
- insulin
- resveratrol
- type 1 diabetes
- type 2 diabetes
- ultrastructure
Collapse
Affiliation(s)
- Hiromitsu Kanamori
- a Department of Cardiology; Gifu University Graduate School of Medicine ; Gifu , Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Lenoir O, Jasiek M, Hénique C, Guyonnet L, Hartleben B, Bork T, Chipont A, Flosseau K, Bensaada I, Schmitt A, Massé JM, Souyri M, Huber TB, Tharaux PL. Endothelial cell and podocyte autophagy synergistically protect from diabetes-induced glomerulosclerosis. Autophagy 2016; 11:1130-45. [PMID: 26039325 DOI: 10.1080/15548627.2015.1049799] [Citation(s) in RCA: 204] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The glomerulus is a highly specialized capillary tuft, which under pressure filters large amounts of water and small solutes into the urinary space, while retaining albumin and large proteins. The glomerular filtration barrier (GFB) is a highly specialized filtration interface between blood and urine that is highly permeable to small and midsized solutes in plasma but relatively impermeable to macromolecules such as albumin. The integrity of the GFB is maintained by molecular interplay between its 3 layers: the glomerular endothelium, the glomerular basement membrane and podocytes, which are highly specialized postmitotic pericytes forming the outer part of the GFB. Abnormalities of glomerular ultrafiltration lead to the loss of proteins in urine and progressive renal insufficiency, underlining the importance of the GFB. Indeed, albuminuria is strongly predictive of the course of chronic nephropathies especially that of diabetic nephropathy (DN), a leading cause of renal insufficiency. We found that high glucose concentrations promote autophagy flux in podocyte cultures and that the abundance of LC3B II in podocytes is high in diabetic mice. Deletion of Atg5 specifically in podocytes resulted in accelerated diabetes-induced podocytopathy with a leaky GFB and glomerulosclerosis. Strikingly, genetic alteration of autophagy on the other side of the GFB involving the endothelial-specific deletion of Atg5 also resulted in capillary rarefaction and accelerated DN. Thus autophagy is a key protective mechanism on both cellular layers of the GFB suggesting autophagy as a promising new therapeutic strategy for DN.
Collapse
Key Words
- BUN, blood urea nitrogen
- CASP3, caspase 3, apoptosis-related cysteine peptidase
- Cdh5, cadherin 5
- DM, diabetes mellitus
- DN, diabetic nephropathy
- ESRD, end-stage renal disease
- GBM, glomerular basement membrane
- GEC, glomerular endothelial cells
- GFB, glomerular filtration barrier
- MAP1LC3A/B/LC3A/B), microtubule-associated protein 1 light chain 3 α/β
- MTOR, mechanistic target of rapamycin
- Nphs2, nephrosis 2, podocin
- SQSTM1, sequestosome 1
- STZ, streptozotocin
- TEM, transmission electron microscopy
- TUBA, tubulin
- autophagy
- diabetic nephropathy
- endothelial cells
- podocytes
- proteinuria
- sclerosis
- α, WT1, Wilms tumor 1
Collapse
Affiliation(s)
- Olivia Lenoir
- a Paris Cardiovascular Research Center; Institut National de la Santé et de la Recherche Médicale (INSERM) ; Paris , France
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Abstract
Primary cilium is an organelle that plays significant roles in a number of cellular functions ranging from cell mechanosensation, proliferation, and differentiation to apoptosis. Autophagy is an evolutionarily conserved cellular function in biology and indispensable for cellular homeostasis. Both cilia and autophagy have been linked to different types of genetic and acquired human diseases. Their interaction has been suggested very recently, but the underlying mechanisms are still not fully understood. We examined autophagy in cells with suppressed cilia and measured cilium length in autophagy-activated or -suppressed cells. It was found that autophagy was repressed in cells with short cilia. Further investigation showed that MTOR activation was enhanced in cilia-suppressed cells and the MTOR inhibitor rapamycin could largely reverse autophagy suppression. In human kidney proximal tubular cells (HK2), autophagy induction was associated with cilium elongation. Conversely, autophagy inhibition by 3-methyladenine (3-MA) and chloroquine (CQ) as well as bafilomycin A1 (Baf) led to short cilia. Cilia were also shorter in cultured atg5-knockout (KO) cells and in atg7-KO kidney proximal tubular cells in mice. MG132, an inhibitor of the proteasome, could significantly restore cilium length in atg5-KO cells, being concomitant with the proteasome activity. Together, the results suggest that cilia and autophagy regulate reciprocally through the MTOR signaling pathway and ubiquitin-proteasome system.
Collapse
Key Words
- 3-MA, 3-methyladenine
- 70kDa, polypeptide 1
- ANKS6, ankyrin repeat and sterile α motif domain containing 6
- ATG/atg, autophagy-related
- Ac-TUBA, acetylated-tubulin α
- Baf, bafilomycin A1
- CF, confluence
- CQ, chloroquine
- DAPI, 4′-6-diamidino-2-phenylindole
- FBS, fetal bovine serum
- HK2, human kidney proximal tubular cells
- IFT, intraflagellar transport
- KAP3, kinesin family-associated protein 3
- KD, knockdown
- KIF3A/3B, kinesin family member 3A/3B
- KO, knockout
- LTA, lotus tetragonolobus agglutinin
- MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3 β
- MEF, mouse embryonic fibroblast
- MTOR
- MTOR, mechanistic target of rapamycin
- OFD1, oral-ficial-digital syndrome 1
- PBS, phosphate-buffered saline
- PKD, polycystic kidney disease
- RKRB, Krebs-Henseleit saline containing 25 mM NaHCO3
- RPS6KB1, ribosomal protein S6 kinase
- Rapa, rapamycin
- SD, standard deviation
- autophagy
- cilia
- polycystic kidney disease
- proteasome
Collapse
Affiliation(s)
- Shixuan Wang
- a Department of Cellular Biology and Anatomy ; Medical College of Georgia; Georgia Reagents University and Charlie Norwood VA Medical Center ; Augusta , GA USA
| | | | | | | |
Collapse
|
8
|
Abstract
Genetic variations in the autophagic pathway influence genetic predispositions to Crohn disease. Autophagy, the major lysosomal pathway for degrading and recycling cytoplasmic material, constitutes an important homeostatic cellular process. Of interest, single-nucleotide polymorphisms in ATG16L1 (autophagy-related 16-like 1 [S. cerevisiae]), a key component in the autophagic response to invading pathogens, have been associated with an increased risk of developing Crohn disease. The most common and well-studied genetic variant of ATG16L1 (rs2241880; leading to a T300A conversion) exhibits a strong association with risk for developing Crohn disease. The rs2241880 variant plays a crucial role in pathogen clearance, resulting in imbalanced cytokine production, and is linked to other biological processes, such as the endoplasmic reticulum stress/unfolded protein response. In this review, we focus on the importance of ATG16L1 and its genetic variant (T300A) within the elementary biological processes linked to Crohn disease.
Collapse
Key Words
- ATG16L1
- ATG16L1, autophagy-related 16-like 1 (S. cerevisiae)
- BCL2, B-cell CLL/lymphoma 2
- Crohn disease
- DCs, dendritic cells
- ER, endoplasmic reticulum
- GWAS, genome-wide association studies
- IBD, inflammatory bowel disease
- MDP, muramyl dipeptide
- MTOR, mechanistic target of rapamycin
- NFKB, nuclear factor of kappa light polypeptide gene enhancer in B-cells
- NOD2
- NOD2, nucleotide-binding oligomerization domain containing 2
- RIPK2, receptor-interacting serine-threonine kinase 2
- SNP, single-nucleotide polymorphism
- T300A, threonine-to-alanine substitution at amino acid position 300
- TNF/TNF-α, tumor necrosis factor
- UC, ulcerative colitis
- ULK1, unc-51 like autophagy-activating kinase 1
- XBP1, X-box binding protein 1
- autophagy
- bacterial clearance
- endoplasmic reticulum stress
Collapse
Affiliation(s)
- Mohammad Salem
- a Department of Gastroenterology ; Medical Section; Herlev Hospital; University of Copenhagen ; Copenhagen , Denmark
| | | | | | | | | |
Collapse
|
9
|
Zhang J, Ng S, Wang J, Zhou J, Tan SH, Yang N, Lin Q, Xia D, Shen HM. Histone deacetylase inhibitors induce autophagy through FOXO1-dependent pathways. Autophagy 2016; 11:629-42. [PMID: 25919885 DOI: 10.1080/15548627.2015.1023981] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Autophagy is a catabolic process in response to starvation or other stress conditions to sustain cellular homeostasis. At present, histone deacetylase inhibitors (HDACIs) are known to induce autophagy in cells through inhibition of mechanistic target of rapamycin (MTOR) pathway. FOXO1, an important transcription factor regulated by AKT, is also known to play a role in autophagy induction. At present, the role of FOXO1 in the HDACIs-induced autophagy has not been reported. In this study, we first observed that HDACIs increased the expression of FOXO1 at the mRNA and protein level. Second, we found that FOXO1 transcriptional activity was enhanced by HDACIs, as evidenced by increased FOXO1 nuclear accumulation and transcriptional activity. Third, suppression of FOXO1 function by siRNA knockdown or by a chemical inhibitor markedly blocked HDACIs-induced autophagy. Moreover, we found that FOXO1-mediated autophagy is achieved via its transcriptional activation, leading to a dual effect on autophagy induction: (i) enhanced expression of autophagy-related (ATG) genes, and (ii) suppression of MTOR via transcription of the SESN3 (sestrin 3) gene. Finally, we found that inhibition of autophagy markedly enhanced HDACIs-mediated cell death, indicating that autophagy serves as an important cell survival mechanism. Taken together, our studies reveal a novel function of FOXO1 in HDACIs-mediated autophagy in human cancer cells and thus support the development of a novel therapeutic strategy by combining HDACIs and autophagy inhibitors in cancer therapy.
Collapse
Key Words
- ATG, autophagy-related
- BAF, bafilomycin A1
- CQ, chloroquine
- FOXO, forkhead box O
- FOXO1
- GFP, green fluorescent protein
- MAP1LC3/LC3, microtubule-associated protein 1 light chain 3
- MEF, mouse embryonic fibroblast
- MTOR
- MTOR, mechanistic target of rapamycin
- PI3K, phosphoinositide 3-kinase
- SAHA, suberoylanilide hydroxamic acid
- TSA, trichostatin A
- TSC, tuberous sclerosis
- autophagy
- cancer
- cell death
- histone deacetylase inhibitors
- siRNA, short interfering RNA
Collapse
Affiliation(s)
- Jianbin Zhang
- a Department of Physiology ; Yong Loo Lin School of Medicine; National University of Singapore ; Singapore
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Xu D, Zhang T, Xiao J, Zhu K, Wei R, Wu Z, Meng H, Li Y, Yuan J. Modification of BECN1 by ISG15 plays a crucial role in autophagy regulation by type I IFN/interferon. Autophagy 2016; 11:617-28. [PMID: 25906440 DOI: 10.1080/15548627.2015.1023982] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
ISG15 (ISG15 ubiquitin-like modifier), a ubiquitin-like protein, is one of the major type I IFN (interferon) effector systems. ISG15 can be conjugated to target proteins (ISGylation) via the stepwise action of E1, E2, and E3 enzymes. Conjugated ISG15 can be removed (deISGylated) from target proteins by USP18 (ubiquitin-specific peptidase 18). Here we investigated the role of deISGylation by USP18 in regulating autophagy and EGFR degradation in cells treated with type I IFNs. We show that type I IFN induced expression of ISG15 leads to ISGylation of BECN1 at Lys117, as well as Lys263, Lys265, and Lys266 which competes with Lys63 ubiquitination of BECN1. We demonstrate that ISGylation of BECN1 at Lys117, as well as Lys263, Lys265, and Lys266 serve an important role in negative regulation of intracellular processes including autophagy and EGFR degradation that are critically dependent upon the activity of class III PtdIns 3-kinase. Our studies provide fundamental new mechanistic insights into the innate immunity response implemented by type I IFNs.
Collapse
Key Words
- AKT/PKB, v-akt murine thymoma viral oncogene homolog
- ATG, autophagy-related
- BECN1
- BECN1, Beclin 1, autophagy-related
- EGF, epidermal growth factor
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- HERC5, HECT, and RLD domain containing E3 ubiquitin protein ligase 5
- IFN, interferon
- ISG15
- ISG15, ISG15 ubiquitin-like modifier
- LC3, microtubule-associated protein 1 light chain 3
- MTOR, mechanistic target of rapamycin
- MX1, MX dynamin-like GTPase 1
- PIK3C3, phosphatidylinositol 3-kinase, catalytic subunit type 3
- RPS6KB, ribosomal protein S6 kinase, 70kDa, polypeptide
- SQSTM1/p62, sequestosome 1
- UBA7, ubiquitin-like modifier activating enzyme 7
- USP18
- USP18, ubiquitin specific peptidase 18
- Ub, ubiquitin
- autophagy
- type I IFN
Collapse
Affiliation(s)
- Daichao Xu
- a Interdisciplinary Research Center on Biology and Chemistry; Shanghai Institute of Organic Chemistry; Chinese Academy of Sciences ; Shanghai , China
| | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Guo S, Liang Y, Murphy SF, Huang A, Shen H, Kelly DF, Sobrado P, Sheng Z. A rapid and high content assay that measures cyto-ID-stained autophagic compartments and estimates autophagy flux with potential clinical applications. Autophagy 2016; 11:560-72. [PMID: 25714620 PMCID: PMC4502761 DOI: 10.1080/15548627.2015.1017181] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The lack of a rapid and quantitative autophagy assay has substantially hindered the development and implementation of autophagy-targeting therapies for a variety of human diseases. To address this critical issue, we developed a novel autophagy assay using the newly developed Cyto-ID fluorescence dye. We first verified that the Cyto-ID dye specifically labels autophagic compartments with minimal staining of lysosomes and endosomes. We then developed a new Cyto-ID fluorescence spectrophotometric assay that makes it possible to estimate autophagy flux based on measurements of the Cyto-ID-stained autophagic compartments. By comparing to traditional autophagy approaches, we found that this assay yielded a more sensitive, yet less variable, quantification of the stained autophagic compartments and the estimate of autophagy flux. Furthermore, we tested the potential application of this autophagy assay in high throughput research by integrating it into an RNA interference (RNAi) screen and a small molecule screen. The RNAi screen revealed WNK2 and MAP3K6 as autophagy-modulating genes, both of which inhibited the MTOR pathway. Similarly, the small molecule screen identified sanguinarine and actinomycin D as potent autophagy inducers in leukemic cells. Moreover, we successfully detected autophagy responses to kinase inhibitors and chloroquine in normal or leukemic mice using this assay. Collectively, this new Cyto-ID fluorescence spectrophotometric assay provides a rapid, reliable quantification of autophagic compartments and estimation of autophagy flux with potential applications in developing autophagy-related therapies and as a test to monitor autophagy responses in patients being treated with autophagy-modulating drugs.
Collapse
Key Words
- 3-MA, 3-methyladenine
- Cyto-ID
- FBS, fetal bovine serum
- GFP, green fluorescent protein
- LAMP1, lysosomal-associated membrane protein 1
- MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3 beta
- MAP3K6, mitogen-activated protein kinase kinase kinase 6
- MDC, monodansylcadaverine
- MTOR, mechanistic target of rapamycin
- NS, nonsilencing
- RAB5A, member RAS oncogene family
- RNA interference screen
- RNAi, RNA interference
- SQSTM1, sequestosome 1
- WNK2, WNK lysine deficient protein kinase 2
- autophagy
- autophagy flux
- autophagy response
- mRFP, monomeric red fluorescent protein
- shRNA, short-hairpin RNA
- small molecule screen
- spectrophotometric assay
Collapse
Affiliation(s)
- Sujuan Guo
- a Virginia Tech Carilion Research Institute ; Roanoke , VA USA
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Pedro JMBS, Wei Y, Sica V, Maiuri MC, Zou Z, Kroemer G, Levine B. BAX and BAK1 are dispensable for ABT-737-induced dissociation of the BCL2-BECN1 complex and autophagy. Autophagy 2016; 11:452-9. [PMID: 25715028 PMCID: PMC4502763 DOI: 10.1080/15548627.2015.1017191] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Disruption of the complex of BECN1 with BCL2 or BCL2L1/BCL-XL is an essential switch that turns on cellular autophagy in response to environmental stress or treatment with BH3 peptidomimetics. Recently, it has been proposed that BCL2 and BCL2L1/BCL-XL may inhibit autophagy indirectly through a mechanism dependent on the proapoptotic BCL2 family members, BAX and BAK1. Here we report that the BH3 mimetic, ABT-737, induces autophagy in parallel with disruption of BCL2-BECN1 binding in 2 different apoptosis-deficient cell types lacking BAX and BAK1, namely in mouse embryonic fibroblasts cells and in human colon cancer HCT116 cells. We conclude that the BH3 mimetic ABT-737 induces autophagy through a BAX and BAK1-independent mechanism that likely involves disruption of BECN1 binding to antiapoptotic BCL2 family members.
Collapse
Key Words
- ABT-737
- ACTB, actin, β
- BAK1
- BAK1, BCL2-antagonist/killer 1
- BAX
- BAX, BCL2-associated X protein
- BCL2
- BCL2, B-cell CLL/lymphoma 2
- BECN1 (Beclin 1)
- BECN1, Beclin 1, autophagy-related
- Baf A1, bafilomycin A1
- DKO, double-knockout
- FBS, fetal bovine serum
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- HBSS, Hanks’ balanced salt solution
- HRP, horseradish peroxidase
- MAP1LC3/LC3, microtubule-associated protein 1 light chain 3
- MCL1, myeloid cell leukemia 1
- MEFs, mouse embryonic fibroblasts
- MTOR, mechanistic target of rapamycin
- PBS, phosphate-buffered saline
- SQSTM1, sequestosome 1
- STS, staurosporine
- WT, wild type
- apoptosis
- autophagy
Collapse
Affiliation(s)
- Jose Manuel Bravo-San Pedro
- a Equipe 11 labellisée pas la Ligue Nationale contre le Cancer ; Center de Recherche des Cordeliers ; Paris , France
| | | | | | | | | | | | | |
Collapse
|
13
|
Namkoong S, Lee KI, Lee JI, Park R, Lee EJ, Jang IS, Park J. The integral membrane protein ITM2A, a transcriptional target of PKA-CREB, regulates autophagic flux via interaction with the vacuolar ATPase. Autophagy 2016; 11:756-68. [PMID: 25951193 PMCID: PMC4509440 DOI: 10.1080/15548627.2015.1034412] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The PKA-CREB signaling pathway is involved in many cellular processes including autophagy. Recent studies demonstrated that PKA-CREB inhibits autophagy in yeast; however, the role of PKA-CREB signaling in mammalian cell autophagy has not been fully characterized. Here, we report that the integral membrane protein ITM2A expression is positively regulated by PKA-CREB signaling and ITM2A expression interferes with autophagic flux by interacting with vacuolar ATPase (v-ATPase). The ITM2A promoter contains a CRE element, and mutation at the CRE consensus site decreases the promoter activity. Forskolin treatment and PKA expression activate the ITM2A promoter confirming that ITM2A expression is dependent on the PKA-CREB pathway. ITM2A expression results in the accumulation of autophagosomes and interferes with autolysosome formation by blocking autophagic flux. We demonstrated that ITM2A physically interacts with v-ATPase and inhibits lysosomal function. These results support the notion that PKA-CREB signaling pathway regulates ITM2A expression, which negatively regulates autophagic flux by interfering with the function of v-ATPase.
Collapse
Key Words
- BafA1, bafilomycin A1
- CRE, cAMP response element
- CREB
- CREB, cAMP responsive element binding protein
- ChIP, chromatin immunoprecipitation
- EBSS, Earle's balanced salt solution
- ITM2A
- ITM2A, integral membrane protein 2A
- LAMP1, lysosomal-associated membrane protein 1
- MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3 β
- MAPK, mitogen-activated protein kinase
- MTOR, mechanistic target of rapamycin
- PKA
- PKA, protein kinase A
- SQSTM1, sequestosome 1
- TPA, 12-O-tetradecanoylphorbol-13-acetate
- autophagy
- cAMP, cyclic adenosine monophosphate
- tfLC3, tandem fluorescent-tagged LC3
- v-ATPase
- v-ATPase, vacuolar ATPase.
Collapse
Affiliation(s)
- Sim Namkoong
- a Division of Biological Science and Technology; Yonsei University ; Wonju , Korea
| | | | | | | | | | | | | |
Collapse
|
14
|
Mauro-Lizcano M, Esteban-Martínez L, Seco E, Serrano-Puebla A, Garcia-Ledo L, Figueiredo-Pereira C, Vieira HLA, Boya P. New method to assess mitophagy flux by flow cytometry. Autophagy 2016; 11:833-43. [PMID: 25945953 DOI: 10.1080/15548627.2015.1034403] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial autophagy, also known as mitophagy, is an autophagosome-based mitochondrial degradation process that eliminates unwanted or damaged mitochondria after cell stress. Most studies dealing with mitophagy rely on the analysis by fluorescence microscopy of mitochondrial-autophagosome colocalization. However, given the fundamental role of mitophagy in the physiology and pathology of organisms, there is an urgent need for novel quantitative methods with which to study this process. Here, we describe a flow cytometry-based approach to determine mitophagy by using MitoTracker Deep Red, a widely used mitochondria-selective probe. Used in combination with selective inhibitors it may allow for the determination of mitophagy flux. Here, we test the validity of the use of this method in cell lines and in primary cell and tissue cultures.
Collapse
Key Words
- 3MA, 3-methyladenine
- Atg, autophagy-related
- CCCP, carbonyl cyanide m-chlorophenyl hydrazone
- COX4I1, cytochrome c oxidase subunit IV isoform 1
- Co, control
- CsA, cyclosporin A
- E, embryonic day
- EBSS, Earle's balanced salt solution
- FIS, fisetin
- HCQ, hydroxychloroquine
- KO, knockout
- LC3, MAP1LC3/LC3
- MEFs, mouse embryonic fibroblasts
- MTDR, MitoTracker Deep Red
- MTOR, mechanistic target of rapamycin
- N+L, ammonium chloride + leupeptin
- NAM, nicotinamide
- P, postnatal day
- PARK2, Parkin RBR E3 ubiquitin protein ligase
- PHEN, 1,10-phenanthroline
- PINK1, PTEN-induced putative kinase 1
- Rapa, rapamycin
- TIMM23, translocase of inner mitochondrial membrane 23 homolog (yeast)
- TOMM20, translocase of outer mitochondrial membrane 20 homolog (yeast)
- TOMM40, translocase of outer mitochondrial membrane 40 homolog (yeast)
- WM, wortmannin
- WT, wild type
- astrocyte primary culture
- autophagic flux
- autophagy
- flow cytometry
- mitochondria
- mitophagic flux
- mitophagy
- neurodegeneration
- retina
- ΔΨ, mitochondrial membrane potential
Collapse
Affiliation(s)
- Marta Mauro-Lizcano
- a Departament of Cellular and Molecular Biology; Centro de Investigaciones Biológicas; CSIC ; Madrid , Spain
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Shi Y, Tan SH, Ng S, Zhou J, Yang ND, Koo GB, McMahon KA, Parton RG, Hill MM, Del Pozo MA, Kim YS, Shen HM. Critical role of CAV1/caveolin-1 in cell stress responses in human breast cancer cells via modulation of lysosomal function and autophagy. Autophagy 2016; 11:769-84. [PMID: 25945613 DOI: 10.1080/15548627.2015.1034411] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
CAV1 (caveolin 1, caveolae protein, 22kDa) is well known as a principal scaffolding protein of caveolae, a specialized plasma membrane structure. Relatively, the caveolae-independent function of CAV1 is less studied. Autophagy is a process known to involve various membrane structures, including autophagosomes, lysosomes, and autolysosomes for degradation of intracellular proteins and organelles. Currently, the function of CAV1 in autophagy remains largely elusive. In this study, we demonstrate for the first time that CAV1 deficiency promotes both basal and inducible autophagy. Interestingly, the promoting effect was found mainly in the late stage of autophagy via enhancing lysosomal function and autophagosome-lysosome fusion. Notably, the regulatory function of CAV1 in lysosome and autophagy was found to be caveolae-independent, and acts through lipid rafts. Furthermore, the elevated autophagy level induced by CAV1 deficiency serves as a cell survival mechanism under starvation. Importantly, downregulation of CAV1 and enhanced autophagy level were observed in human breast cancer cells and tissues. Taken together, our data reveal a novel function of CAV1 and lipid rafts in breast cancer development via modulation of lysosomal function and autophagy.
Collapse
Key Words
- ATP6V0D1, ATPase H+ transporting lysosomal 38kDa, V0 subunit d1
- Baf, bafilomycin A1
- CAV1, caveolin 1
- CHO, water-soluble cholesterol
- CQ, choloroquine
- CTSL, cathepsin L
- CTxB, cholera toxin subunit B
- DRF, detergent-resistant fraction
- DSF, detergent-soluble fraction
- EGF, epidermal growth factor
- KO, knockout
- LAMP1, lysosomal-associated membrane protein 1
- MAP1LC3/LC3, microtubule-associated protein 1 light chain 3
- MBCD, methyl-β-cyclodextrin
- MEF, mouse embryonic fibroblasts
- MTOR, mechanistic target of rapamycin
- PBS, phosphate-buffered saline
- PI, propidium iodide
- PLA, proximity ligation assay
- PTRF, polymerase I and transcript release factor
- TFRC, transferrin receptor
- TSC, tuberous sclerosis complex
- WT, wild type.
- autophagy
- breast cancer
- caveolin 1
- lipid rafts
- lysosome
- tfLC3B, mRFP-GFP tandem fluorescent-tagged LC3B
Collapse
Affiliation(s)
- Yin Shi
- a Department of Physiology; Yong Loo Lin School of Medicine; National University of Singapore ; Singapore
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
Protein quality control (proteostasis) depends on constant protein degradation and resynthesis, and is essential for proper homeostasis in systems from single cells to whole organisms. Cells possess several mechanisms and processes to maintain proteostasis. At one end of the spectrum, the heat shock proteins modulate protein folding and repair. At the other end, the proteasome and autophagy as well as other lysosome-dependent systems, function in the degradation of dysfunctional proteins. In this review, we examine how these systems interact to maintain proteostasis. Both the direct cellular data on heat shock control over autophagy and the time course of exercise-associated changes in humans support the model that heat shock response and autophagy are tightly linked. Studying the links between exercise stress and molecular control of proteostasis provides evidence that the heat shock response and autophagy coordinate and undergo sequential activation and downregulation, and that this is essential for proper proteostasis in eukaryotic systems.
Collapse
Key Words
- AKT, v-akt murine thymoma viral oncogene homolog 1
- AMPK, adenosine monophosphate-activated protein kinase
- ATG, autophagy-related
- BECN1, Beclin 1, autophagy related
- EIF4EBP1, eukaryotic translation initiation factor 4E binding protein 1
- ER, endoplasmic reticulum
- FOXO, forkhead box O
- HSF1, heat shock transcription factor 1
- HSP, heat shock protein
- HSP70
- HSPA8/HSC70, heat shock 70kDa protein 8
- IL, interleukin
- LC3, MAP1LC3, microtubule-associated protein 1 light chain 3
- MTMR14/hJumpy, myotubularin related protein 14
- MTOR, mechanistic target of rapamycin
- NR1D1/Rev-Erb-α, nuclear receptor subfamily 1, group D, member 1
- PBMC, peripheral blood mononuclear cell
- PPARGC1A/PGC-1α, peroxisome proliferator-activated receptor, gamma, coactivator 1 α
- RHEB, Ras homolog enriched in brain
- SOD, superoxide dismutase
- SQSTM1/p62, sequestosome 1
- TPR, translocated promoter region, nuclear basket protein
- TSC, tuberous sclerosis complex
- ULK1, unc-51 like autophagy activating kinase 1
- autophagy
- exercise
- heat shock response
- humans
- protein breakdown
- protein synthesis
Collapse
Affiliation(s)
- Karol Dokladny
- a Department of Internal Medicine; Health Sciences Center; Health, Exercise & Sports Science of University of New Mexico ; Albuquerque , NM USA
| | | | | |
Collapse
|
17
|
Zeng X, Zhao H, Li Y, Fan J, Sun Y, Wang S, Wang Z, Song P, Ju D. Targeting Hedgehog signaling pathway and autophagy overcomes drug resistance of BCR-ABL-positive chronic myeloid leukemia. Autophagy 2016; 11:355-72. [PMID: 25701353 DOI: 10.4161/15548627.2014.994368] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The frontline tyrosine kinase inhibitor (TKI) imatinib has revolutionized the treatment of patients with chronic myeloid leukemia (CML). However, drug resistance is the major clinical challenge in the treatment of CML. The Hedgehog (Hh) signaling pathway and autophagy are both related to tumorigenesis, cancer therapy, and drug resistance. This study was conducted to explore whether the Hh pathway could regulate autophagy in CML cells and whether simultaneously regulating the Hh pathway and autophagy could induce cell death of drug-sensitive or -resistant BCR-ABL(+) CML cells. Our results indicated that pharmacological or genetic inhibition of Hh pathway could markedly induce autophagy in BCR-ABL(+) CML cells. Autophagic inhibitors or ATG5 and ATG7 silencing could significantly enhance CML cell death induced by Hh pathway suppression. Based on the above findings, our study demonstrated that simultaneously inhibiting the Hh pathway and autophagy could markedly reduce cell viability and induce apoptosis of imatinib-sensitive or -resistant BCR-ABL(+) cells. Moreover, this combination had little cytotoxicity in human peripheral blood mononuclear cells (PBMCs). Furthermore, this combined strategy was related to PARP cleavage, CASP3 and CASP9 cleavage, and inhibition of the BCR-ABL oncoprotein. In conclusion, this study indicated that simultaneously inhibiting the Hh pathway and autophagy could potently kill imatinib-sensitive or -resistant BCR-ABL(+) cells, providing a novel concept that simultaneously inhibiting the Hh pathway and autophagy might be a potent new strategy to overcome CML drug resistance.
Collapse
Key Words
- ACTB, actin
- AKT/protein kinase B, v-akt murine thymoma viral oncogene homolog
- ATG, autophagy-related
- BCC, basal cell carcinoma
- BCR-ABL
- BCR-ABL, breakpoint cluster region-ABL proto-oncogene, non-receptor tyrosine kinase
- Bafi A1, bafilomycin A1
- CASP, caspase
- CML
- CML, chronic myeloid leukemia
- CQ, chloroquine
- EIF4EBP1, eukaryotic translation initiation factor 4E binding protein 1
- HCQ, hydroxychloroquine
- Hh, Hedgehog
- MAP1LC3B, microtubule-associated protein 1 light chain 3 β
- MTOR, mechanistic target of rapamycin
- PARP, poly (ADP-ribose) polymerase
- PBMC, human peripheral blood mononuclear cell
- PCR, polymerase chain reaction
- RPS6KB, ribosomal protein S6 kinase, 70kDa
- SQSTM1, sequestosome 1
- TKI, tyrosine kinase inhibitor
- apoptosis-related cysteine peptidase
- autophagy
- drug resistance
- hedgehog pathway
- siRNA, small interfering RNA
- β
Collapse
Affiliation(s)
- Xian Zeng
- a Department of Biosynthesis and Key Laboratory of Smart Drug Delivery; MOE; School of Pharmacy ; Fudan University ; Shanghai , China
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Rah B, ur Rasool R, Nayak D, Yousuf SK, Mukherjee D, Kumar LD, Goswami A. PAWR-mediated suppression of BCL2 promotes switching of 3-azido withaferin A (3-AWA)-induced autophagy to apoptosis in prostate cancer cells. Autophagy 2016; 11:314-31. [PMID: 25803782 DOI: 10.1080/15548627.2015.1017182] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
An active medicinal component of plant origin with an ability to overcome autophagy by inducing apoptosis should be considered a therapeutically active lead pharmacophore to control malignancies. In this report, we studied the effect of concentration-dependent 3-AWA (3-azido withaferin A) sensitization to androgen-independent prostate cancer (CaP) cells which resulted in a distinct switching of 2 interrelated conserved biological processes, i.e. autophagy and apoptosis. We have observed 3 distinct parameters which are hallmarks of autophagy in our studies. First, a subtoxic concentration of 3-AWA resulted in an autophagic phenotype with an elevation of autophagy markers in prostate cancer cells. This led to a massive accumulation of MAP1LC3B and EGFP-LC3B puncta coupled with gradual degradation of SQSTM1. Second, higher toxic concentrations of 3-AWA stimulated ER stress in CaP cells to turn on apoptosis within 12 h by elevating the expression of the proapoptotic protein PAWR, which in turn suppressed the autophagy-related proteins BCL2 and BECN1. This inhibition of BECN1 in CaP cells, leading to the disruption of the BCL2-BECN1 interaction by overexpressed PAWR has not been reported so far. Third, we provide evidence that pawr-KO MEFs exhibited abundant autophagy signs even at toxic concentrations of 3-AWA underscoring the relevance of PAWR in switching of autophagy to apoptosis. Last but not least, overexpression of EGFP-LC3B and DS-Red-BECN1 revealed a delayed apoptosis turnover at a higher concentration of 3-AWA in CaP cells. In summary, this study provides evidence that 3-AWA is a strong anticancer candidate to abrogate protective autophagy. It also enhanced chemosensitivity by sensitizing prostate cancer cells to apoptosis through induction of PAWR endorsing its therapeutic potential.
Collapse
Key Words
- 3-AWA, 3-azido withaferin A
- 3-azido withaferin A
- AO, acridine orange
- ATG, autophagy-related
- AVOs, acidic vesicular organelles
- BAD, BCL2-associated agonist of cell death
- BAF A1, bafilomycin A1
- BCL2
- BCL2, B-cell CLL/lymphoma 2
- BECN1
- BECN1, Beclin 1, autophagy-related
- CASP3, caspase 3
- CASP9, caspase 9
- CQ, chloroquine
- CYCS, cytochrome c, somatic
- CaP, prostate cancer cells
- DAPI, 4’6-diamidino-2-phenylindole
- DCF, dichlorofluorescein
- DDIT3/CHOP, DNA-damage-inducible transcript 3
- EIF2AK3/PERK, eukaryotic initiation translation factor 2-α kinase 3
- ER, endoplasmic reticulum
- HSPA5/GRP78, heat shock 70kDa protein 5 (glucose-regulated protein, 78kDa)
- MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3 β
- MDC, monodansylcadaverine
- MEFs, mouse embryonic fibroblasts
- MMPψ, mitochondrial membrane potential
- MTOR, mechanistic target of rapamycin
- NAC, N-acetyl-L-cysteine
- PARP1, poly (ADP-ribose) polymerase 1
- PAWR
- PAWR/Par-4, PRKC, apoptosis, WT1, regulator
- PRKCZ/PKCζ, protein kinase C, zeta
- SQSTM1/p62, sequestosome 1
- WT1, Wilms tumor 1
- apoptosis
- autophagy
- myrAKT1, myristoylated v-akt murine thymoma viral oncogene homolog 1
Collapse
Affiliation(s)
- Bilal Rah
- a Academy of Scientific & Innovative Research (AcSIR) ; New Delhi , India
| | | | | | | | | | | | | |
Collapse
|
19
|
He J, Yu JJ, Xu Q, Wang L, Zheng JZ, Liu LZ, Jiang BH. Downregulation of ATG14 by EGR1-MIR152 sensitizes ovarian cancer cells to cisplatin-induced apoptosis by inhibiting cyto-protective autophagy. Autophagy 2016; 11:373-84. [PMID: 25650716 DOI: 10.1080/15548627.2015.1009781] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cisplatin is commonly used in ovarian cancer treatment by inducing apoptosis in cancer cells as a result of lethal DNA damage. However, the intrinsic and acquired resistance to cisplatin in cancer cells remains a big challenge for improving overall survival. The cyto-protective functions of autophagy in cancer cells have been suggested as a potential mechanism for chemoresistance. Here, we reported MIR152 as a new autophagy-regulating miRNA that plays a role in cisplatin-resistance. We showed that MIR152 expression was dramatically downregulated in the cisplatin-resistant cell lines A2780/CP70, SKOV3/DDP compared with their respective parental cells, and in ovarian cancer tissues associated with cisplatin-resistance. Overexpression of MIR152 sensitized cisplatin-resistant ovarian cancer cells by reducing cisplatin-induced autophagy, enhancing cisplatin-induced apoptosis and inhibition of cell proliferation. A mouse subcutaneous xenograft tumor model using A2780/CP70 cells with overexpressing MIR152 was established and displayed decreased tumor growth in response to cisplatin. We also identified that ATG14 is a functional target of MIR152 in regulating autophagy inhibition. Furthermore, we found that EGR1 (early growth response 1) regulated the MIR152 gene at the transcriptional level. Ectopic expression of EGR1 enhanced efficacy of chemotherapy in A2780/CP70 cells. More importantly, these findings were relevant to clinical cases. Both EGR1 and MIR152 expression levels were significantly lower in ovarian cancer tissues with high levels of ERCC1 (excision repair cross-complementation group 1), a marker for cisplatin-resistance. Collectively, these data provide insights into novel mechanisms for acquired cisplatin-resistance. Activation of EGR1 and MIR152 may be a useful therapeutic strategy to overcome cisplatin-resistance by preventing cyto-protective autophagy in ovarian cancer.
Collapse
Key Words
- ANXA5, annexin A5
- ATG14
- ATG14, autophagy-related 14
- CSF1, colony stimulating factor 1 (macrophage)
- EGR1
- EGR1, early growth response 1
- ERCC1
- ERCC1, excision repair cross-complementation group 1
- FOXO, forkhead box O
- GFP, green fluorescent protein
- MAPILC3/LC3, microtubule-associated protein 1 light chain 3
- MIR152
- MTOR, mechanistic target of rapamycin
- PI, propidium iodide
- RPS6KB1, ribosomal protein S6 kinase, 70kDa, polypeptide 1
- SQSTM1, sequestosome 1
- autophagy
- cisplatin-resistance
- ovarian cancer
Collapse
Affiliation(s)
- Jun He
- a State Key Lab of Reproductive Medicine and Department of Pathology ; Cancer Center ; Collaborative Innovation Center for Cancer Personalized Medicine; Nanjing Medical University ; Nanjing , China
| | | | | | | | | | | | | |
Collapse
|
20
|
Vucicevic L, Misirkic-Marjanovic M, Paunovic V, Kravic-Stevovic T, Martinovic T, Ciric D, Maric N, Petricevic S, Harhaji-Trajkovic L, Bumbasirevic V, Trajkovic V. Autophagy inhibition uncovers the neurotoxic action of the antipsychotic drug olanzapine. Autophagy 2015; 10:2362-78. [PMID: 25551567 DOI: 10.4161/15548627.2014.984270] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We investigated the role of autophagy, a controlled cellular self-digestion process, in regulating survival of neurons exposed to atypical antipsychotic olanzapine. Olanzapine induced autophagy in human SH-SY5Y neuronal cell line, as confirmed by the increase in autophagic flux and presence of autophagic vesicles, fusion of autophagosomes with lysosomes, and increase in the expression of autophagy-related (ATG) genes ATG4B, ATG5, and ATG7. The production of reactive oxygen species, but not modulation of the main autophagy repressor MTOR or its upstream regulators AMP-activated protein kinase and AKT1, was responsible for olanzapine-triggered autophagy. Olanzapine-mediated oxidative stress also induced mitochondrial depolarization and damage, and the autophagic clearance of dysfunctional mitochondria was confirmed by electron microscopy, colocalization of autophagosome-associated MAP1LC3B (LC3B henceforth) and mitochondria, and mitochondrial association with the autophagic cargo receptor SQSTM1/p62. While olanzapine-triggered mitochondrial damage was not overtly toxic to SH-SY5Y cells, their death was readily initiated upon the inhibition of autophagy with pharmacological inhibitors, RNA interference knockdown of BECN1 and LC3B, or biological free radical nitric oxide. The treatment of mice with olanzapine for 14 d increased the brain levels of autophagosome-associated LC3B-II and mRNA encoding Atg4b, Atg5, Atg7, Atg12, Gabarap, and Becn1. The administration of the autophagy inhibitor chloroquine significantly increased the expression of proapoptotic genes (Trp53, Bax, Bak1, Pmaip1, Bcl2l11, Cdkn1a, and Cdkn1b) and DNA fragmentation in the frontal brain region of olanzapine-exposed animals. These data indicate that olanzapine-triggered autophagy protects neurons from otherwise fatal mitochondrial damage, and that inhibition of autophagy might unmask the neurotoxic action of the drug.
Collapse
Key Words
- AKT1, v-akt murine thymoma viral oncogene homolog 1
- AMPK, AMP-activated protein kinase
- APAF1, apoptotic protease activating factor 1
- ATG, autophagy-related
- BAD, BCL2-associated agonist of cell death
- BAK1, BCL2-antagonist/killer 1
- BAX, BCL2-associated X protein
- BBC3, BCL2 binding component 3
- BCL2, B-cell CLL/lymphoma 2
- BCL2L1, BCL2-like 1
- BCL2L11, BCL2-like 11 (apoptosis facilitator)
- BECN1, Beclin 1, autophagy-related
- BIRC5, baculoviral IAP repeat containing 5
- CDKN1A, cyclin-dependent kinase inhibitor 1A (p21, Cip1)
- CDKN1B, cyclin-dependent kinase inhibitor 1B (p27, Kip1)
- CFLAR/FLIP, CASP8 and FADD-like apoptosis regulator
- COX4I1/COX IV, cytochrome c oxidase IV isoform 1
- DEA-NONOate, diethylamine NONOate
- DHR, dihydrorhodamine 123
- FOXO, forkhead box O
- GABARAP, GABA(A) receptor-associated protein
- LDH, lactate dehydrogenase
- MAP1LC3B, microtubule-associated protein 1 light chain 3 β
- MTOR, mechanistic target of rapamycin
- PAPA-NONOate, propylamine propylamine NONOate
- PMAIP1, phorbol-12-myristate-13-acetate-induced protein 1
- PTEN, phosphatase and tensin homolog
- ROS, reactive oxygen species
- RPS6KB1/S6K1, ribosomal protein S6 kinase, 70kDa, polypeptide 1
- SQSTM1
- SQSTM1/p62, sequestosome 1
- TRP53, transformation related protein 53 (mouse ortholog of human TP53, tumor protein p53)
- TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling
- XIAP, X-linked inhibitor of apoptosis
- antipsychotic
- apoptosis
- autophagy
- mitophagy
- neurotoxicity
- nitric oxide, NO
- olanzapine
- oxidative stress
Collapse
Affiliation(s)
- Ljubica Vucicevic
- a Institute for Biological Research ; University of Belgrade ; Belgrade , Serbia
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Xiong Y, Yepuri G, Forbiteh M, Yu Y, Montani JP, Yang Z, Ming XF. ARG2 impairs endothelial autophagy through regulation of MTOR and PRKAA/AMPK signaling in advanced atherosclerosis. Autophagy 2015; 10:2223-38. [PMID: 25484082 PMCID: PMC4502672 DOI: 10.4161/15548627.2014.981789] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Impaired autophagy function and enhanced ARG2 (arginase 2)-MTOR (mechanistic target of rapamycin) crosstalk are implicated in vascular aging and atherosclerosis. We are interested in the role of ARG2 and the potential underlying mechanism(s) in modulation of endothelial autophagy. Using human nonsenescent “young” and replicative senescent endothelial cells as well as Apolipoprotein E-deficient (apoe−/−Arg2+/+) and Arg2-deficient apoe−/− (apoe−/−arg2−/−) mice fed a high-fat diet for 10 wk as the atherosclerotic animal model, we show here that overexpression of ARG2 in the young cells suppresses endothelial autophagy with concomitant enhanced expression of RICTOR, the essential component of the MTORC2 complex, leading to activation of the AKT-MTORC1-RPS6KB1/S6K1 (ribosomal protein S6 kinase, 70kDa, polypeptide 1) cascade and inhibition of PRKAA/AMPK (protein kinase, AMP-activated, α catalytic subunit). Expression of an inactive ARG2 mutant (H160F) had the same effect. Moreover, silencing RPS6KB1 or expression of a constitutively active PRKAA prevented autophagy suppression by ARG2 or H160F. In senescent cells, enhanced ARG2-RICTOR-AKT-MTORC1-RPS6KB1 and decreased PRKAA signaling and autophagy were observed, which was reversed by silencing ARG2 but not by arginase inhibitors. In line with the above observations, genetic ablation of Arg2 in apoe−/− mice reduced RPS6KB1, enhanced PRKAA signaling and endothelial autophagy in aortas, which was associated with reduced atherosclerosis lesion formation. Taken together, the results demonstrate that ARG2 impairs endothelial autophagy independently of the L-arginine ureahydrolase activity through activation of RPS6KB1 and inhibition of PRKAA, which is implicated in atherogenesis.
Collapse
Key Words
- AKT/PKB, v-akt murine thymoma viral oncogene homolog 1
- ANOVA, analysis of variance
- AR, aortic roots
- ARG1, arginase 1
- ARG2, arginase 2
- ARGINASE
- Atg, autophagy-related
- BEC, S-12 bromoethyl-L-cystine-HCl
- BECN1, Beclin 1, autophagy-related
- Baf A1, bafilomycin A1
- CMV, cytomegalovirus
- EC, endothelial cell
- H160F, inactive mutant of mouse ARG2
- HAEC, human aortic endothelial cells
- HUVEC, human umbilical vein endothelial cells
- LC3, microtubule-associated protein 1 light chain 3
- LDL, low-density lipoprotein
- MTOR
- MTOR, mechanistic target of rapamycin
- NOS3/eNOS, nitric oxide synthase 3 (endothelial cell)
- PE, phosphatidylethanolamine
- PRKAA
- PRKAA/AMPK, protein kinase, AMP-activated, α catalytic subunit
- PtdIns3K, phosphatidylinositol 3-kinase
- RPS6, ribosomal protein S6
- RPS6KB1/S6K1, ribosomal protein S6 kinase, 70kDa, polypeptide 1
- SA-ß-gal, senescence-associated-β-gal
- SMC, smooth muscle cells
- SQSTM1/p62, sequestosome 1
- TP53/p53, tumor protein 53
- Three-MA, 3-methyladenine
- ULK1, unc-51 like autophagy activating kinase 1
- VWF, von Willebrand factor
- WT, wild type
- apoe−/−, Apolipoprotein E-deficient
- arg2−/−, arginase type II deficient
- atherosclerosis
- autophagy
- endothelial cells
- nor-NOHA, Nω-hydroxy-nor-Arginine
- senescence
- shRNA, short hairpin RNA
Collapse
Affiliation(s)
- Yuyan Xiong
- a Vascular Biology; Department of Medicine; Division of Physiology; Faculty of Science ; University of Fribourg ; Fribourg , Switzerland
| | | | | | | | | | | | | |
Collapse
|
22
|
Song YM, Lee YH, Kim JW, Ham DS, Kang ES, Cha BS, Lee HC, Lee BW. Metformin alleviates hepatosteatosis by restoring SIRT1-mediated autophagy induction via an AMP-activated protein kinase-independent pathway. Autophagy 2015; 11:46-59. [PMID: 25484077 DOI: 10.4161/15548627.2014.984271] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Metformin activates both PRKA and SIRT1. Furthermore, autophagy is induced by either the PRKA-MTOR-ULK1 or SIRT1-FOXO signaling pathways. We aimed to elucidate the mechanism by which metformin alleviates hepatosteatosis by examining the molecular interplay between SIRT1, PRKA, and autophagy. ob/ob mice were divided into 3 groups: one with ad libitum feeding of a standard chow diet, one with 300 mg/kg intraperitoneal metformin injections, and one with 3 g/d caloric restriction (CR) for a period of 4 wk. Primary hepatocytes or HepG2 cells were treated with oleic acid (OA) plus high glucose in the absence or presence of metformin. Both CR and metformin significantly improved body weight and glucose homeostasis, along with hepatic steatosis, in ob/ob mice. Furthermore, CR and metformin both upregulated SIRT1 expression and also stimulated autophagy induction and flux in vivo. Metformin also prevented OA with high glucose-induced suppression of both SIRT1 expression and SIRT1-dependent activation of autophagy machinery, thereby alleviating intracellular lipid accumulation in vitro. Interestingly, metformin treatment upregulated SIRT1 expression and activated PRKA even after siRNA-mediated knockdown of PRKAA1/2 and SIRT1, respectively. Taken together, these results suggest that metformin alleviates hepatic steatosis through PRKA-independent, SIRT1-mediated effects on the autophagy machinery.
Collapse
Key Words
- 3MA, 3-methyladenine
- CQ, chloroquine
- CR, caloric restriction
- GOT1/AST, glutamic-oxaloacetic transaminase 1, soluble
- GPT/ALT, glutamic-pyruvate transaminase (alanine aminotransferase)
- IPGTTs, intraperitoneal glucose tolerance tests
- MTOR, mechanistic target of rapamycin
- Met, metformin
- NAFLD, nonalcoholic fatty liver disease
- OA, oleic acid
- ORO, Oil Red O
- PRKA
- PRKA, protein kinase, AMP-activated
- SIRT1
- SIRT1, sirtuin 1
- T-CHO, total cholesterol
- TG, triglyceride
- autophagy
- hepatoseatosis
- metformin
- siRNA, short interfering RNA
Collapse
Affiliation(s)
- Young Mi Song
- a Brain Korea 21 PLUS Project for Medical Science ; Yonsei University College of Medicine ; Seoul , Korea
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Salem M, Ammitzboell M, Nys K, Seidelin JB, Nielsen OH. ATG16L1: A multifunctional susceptibility factor in Crohn disease. Autophagy 2015. [PMID: 25906181 DOI: 10.1080/+15548627.2015.1017187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2022] Open
Abstract
Genetic variations in the autophagic pathway influence genetic predispositions to Crohn disease. Autophagy, the major lysosomal pathway for degrading and recycling cytoplasmic material, constitutes an important homeostatic cellular process. Of interest, single-nucleotide polymorphisms in ATG16L1 (autophagy-related 16-like 1 [S. cerevisiae]), a key component in the autophagic response to invading pathogens, have been associated with an increased risk of developing Crohn disease. The most common and well-studied genetic variant of ATG16L1 (rs2241880; leading to a T300A conversion) exhibits a strong association with risk for developing Crohn disease. The rs2241880 variant plays a crucial role in pathogen clearance, resulting in imbalanced cytokine production, and is linked to other biological processes, such as the endoplasmic reticulum stress/unfolded protein response. In this review, we focus on the importance of ATG16L1 and its genetic variant (T300A) within the elementary biological processes linked to Crohn disease.
Collapse
Key Words
- ATG16L1
- ATG16L1, autophagy-related 16-like 1 (S. cerevisiae)
- BCL2, B-cell CLL/lymphoma 2
- Crohn disease
- DCs, dendritic cells
- ER, endoplasmic reticulum
- GWAS, genome-wide association studies
- IBD, inflammatory bowel disease
- MDP, muramyl dipeptide
- MTOR, mechanistic target of rapamycin
- NFKB, nuclear factor of kappa light polypeptide gene enhancer in B-cells
- NOD2
- NOD2, nucleotide-binding oligomerization domain containing 2
- RIPK2, receptor-interacting serine-threonine kinase 2
- SNP, single-nucleotide polymorphism
- T300A, threonine-to-alanine substitution at amino acid position 300
- TNF/TNF-α, tumor necrosis factor
- UC, ulcerative colitis
- ULK1, unc-51 like autophagy-activating kinase 1
- XBP1, X-box binding protein 1
- autophagy
- bacterial clearance
- endoplasmic reticulum stress
Collapse
Affiliation(s)
- Mohammad Salem
- a Department of Gastroenterology ; Medical Section; Herlev Hospital; University of Copenhagen ; Copenhagen , Denmark
| | | | | | | | | |
Collapse
|
24
|
Florey O, Gammoh N, Kim SE, Jiang X, Overholtzer M. V-ATPase and osmotic imbalances activate endolysosomal LC3 lipidation. Autophagy 2015; 11:88-99. [PMID: 25484071 PMCID: PMC4502810 DOI: 10.4161/15548627.2014.984277] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/25/2014] [Accepted: 07/08/2014] [Indexed: 02/01/2023] Open
Abstract
Recently a noncanonical activity of autophagy proteins has been discovered that targets lipidation of microtubule-associated protein 1 light chain 3 (LC3) onto macroendocytic vacuoles, including macropinosomes, phagosomes, and entotic vacuoles. While this pathway is distinct from canonical autophagy, the mechanism of how these nonautophagic membranes are targeted for LC3 lipidation remains unclear. Here we present evidence that this pathway requires activity of the vacuolar-type H(+)-ATPase (V-ATPase) and is induced by osmotic imbalances within endolysosomal compartments. LC3 lipidation by this mechanism is induced by treatment of cells with the lysosomotropic agent chloroquine, and through exposure to the Heliobacter pylori pore-forming toxin VacA. These data add novel mechanistic insights into the regulation of noncanonical LC3 lipidation and its associated processes, including LC3-associated phagocytosis (LAP), and demonstrate that the widely and therapeutically used drug chloroquine, which is conventionally used to inhibit autophagy flux, is an inducer of LC3 lipidation.
Collapse
Key Words
- ATG, autophagy-related
- Baf, bafilomycin A1
- CALCOCO2/NDP52, calcium binding and coiled-coil domain 2
- CQ, chloroquine
- ConA, concanamycin A
- FYCO1, FYVE and coiled-coil domain containing 1
- GFP, green fluorescent protein
- Helicobacter pylori
- LAMP1, lysosomal-associated membrane protein 1
- LAP
- LAP, LC3-associated phagocytosis
- LC3
- MAP1LC3/LC3, microtubule-associated protein 1 light chain 3
- MTOR, mechanistic target of rapamycin
- PIK3C3/VPS34, phosphatidylinositol 3-kinase
- PtdIns3K, phosphatidylinositol 3-kinase
- PtdIns3P, phosphatidylinositol 3-phosphate
- RB1CC1/FIP200, RB1-inducible coiled-coil 1
- SQSTM1/p62, sequestosome 1
- TEM, transmission electron microscopy
- TLR, toll-like receptor
- ULK1/2, unc-51 like autophagy activating kinase 1/2
- V-ATPase
- V-ATPase, vacuolar-type H+-ATPase
- VacA, vacuolating toxin A
- autophagy
- catalytic subunit type 3
- chloroquine
- entosis
- lysosome
- phagocytosis
Collapse
Affiliation(s)
- Oliver Florey
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
- Signalling Program; The Babraham Institute; Cambridge, UK
| | - Noor Gammoh
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
- Edinburgh Cancer Research UK Center; Institute of Genetics and Molecular Medicine; University of Edinburgh; Edinburgh, UK
| | - Sung Eun Kim
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
- BCMB Allied Program; Weill Cornell Medical College; New York, NY USA
| | - Xuejun Jiang
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
| | - Michael Overholtzer
- Cell Biology Program; Memorial Sloan-Kettering Cancer Center; New York, NY USA
- BCMB Allied Program; Weill Cornell Medical College; New York, NY USA
| |
Collapse
|
25
|
Akin D, Wang SK, Habibzadegah-Tari P, Law B, Ostrov D, Li M, Yin XM, Kim JS, Horenstein N, Dunn WA. A novel ATG4B antagonist inhibits autophagy and has a negative impact on osteosarcoma tumors. Autophagy 2014; 10:2021-35. [PMID: 25483883 PMCID: PMC4502682 DOI: 10.4161/auto.32229] [Citation(s) in RCA: 157] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Autophagy has been implicated in the progression and chemoresistance of various cancers. In this study, we have shown that osteosarcoma Saos-2 cells lacking ATG4B, a cysteine proteinase that activates LC3B, are defective in autophagy and fail to form tumors in mouse models. By combining in silico docking with in vitro and cell-based assays, we identified small compounds that suppressed starvation-induced protein degradation, LC3B lipidation, and formation of autophagic vacuoles. NSC185058 effectively inhibited ATG4B activity in vitro and in cells while having no effect on MTOR and PtdIns3K activities. In addition, this ATG4B antagonist had a negative impact on the development of Saos-2 osteosarcoma tumors in vivo. We concluded that tumor suppression was due to a reduction in ATG4B activity, since we found autophagy suppressed within treated tumors and the compound had no effects on oncogenic protein kinases. Our findings demonstrate that ATG4B is a suitable anti-autophagy target and a promising therapeutic target to treat osteosarcoma.
Collapse
Key Words
- 3MA, 3-methyladenine
- ACTB, actin, beta
- ATG, autophagy-related
- ATG4B
- ATG4B, autophagy-related 4B, cysteine protease
- AV, autophagic vacuole
- BECN1, beclin 1, autophagy related
- CMPase, cytidine monophosphatase
- DMEM, Dulbecco's modified Eagle medium
- ECL, enhanced chemiluminescence
- FYVE, zinc-finger domain named after 4 cysteine-rich proteins: FAB1, YOTB, VAC1, and EEA1
- GABARAPL2, GABA(A) receptor-associated protein-like 2
- GFP, green fluorescent protein
- GST, glutathione S-transferase
- HRP, horseradish peroxidase
- IC50, half maximal inhibitory concentration
- IP, intraperitoneal
- LC3B
- MAP1LC3B/LC3B, microtubule-associated protein 1 light chain 3beta
- MP, melting point
- MTOR, mechanistic target of rapamycin
- NCI, National Cancer Institute
- NMR, nuclear magnetic resonance
- PLA2, phospholipase A2
- PVDF, polyvinylidene difluoride
- PtdIns3K, phosphatidylinositol 3-kinase class III
- PtdIns3P, phosphatidylinositol 3-phosphate
- RFP, red fluorescent protein
- RLU, relative luciferase units
- RPS6, ribosomal protein S6
- RPS6KB1, ribosomal protein S6 kinase, 70kDa, polypeptide 1
- SEM, standard error of the mean
- ULK1/2, unc-51-like autophagy activating kinase 1/2
- and xenografts
- antiautophagy compounds
- dNGLUC, Gaussia luciferase
- in silico docking
- osteosarcoma
Collapse
Affiliation(s)
- Debra Akin
- a Department of Anatomy and Cell Biology ; University of Florida ; Gainesville , FL USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Lu Y, Dong S, Hao B, Li C, Zhu K, Guo W, Wang Q, Cheung KH, Wong CWM, Wu WT, Markus H, Yue J. Vacuolin-1 potently and reversibly inhibits autophagosome-lysosome fusion by activating RAB5A. Autophagy 2014; 10:1895-905. [PMID: 25483964 PMCID: PMC4502727 DOI: 10.4161/auto.32200] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Autophagy is a catabolic lysosomal degradation process essential for cellular homeostasis and cell survival. Dysfunctional autophagy has been associated with a wide range of human diseases, e.g., cancer and neurodegenerative diseases. A large number of small molecules that modulate autophagy have been widely used to dissect this process and some of them, e.g., chloroquine (CQ), might be ultimately applied to treat a variety of autophagy-associated human diseases. Here we found that vacuolin-1 potently and reversibly inhibited the fusion between autophagosomes and lysosomes in mammalian cells, thereby inducing the accumulation of autophagosomes. Interestingly, vacuolin-1 was less toxic but at least 10-fold more potent in inhibiting autophagy compared with CQ. Vacuolin-1 treatment also blocked the fusion between endosomes and lysosomes, resulting in a defect in general endosomal-lysosomal degradation. Treatment of cells with vacuolin-1 alkalinized lysosomal pH and decreased lysosomal Ca2+ content. Besides marginally inhibiting vacuolar ATPase activity, vacuolin-1 treatment markedly activated RAB5A GTPase activity. Expression of a dominant negative mutant of RAB5A or RAB5A knockdown significantly inhibited vacuolin-1-induced autophagosome-lysosome fusion blockage, whereas expression of a constitutive active form of RAB5A suppressed autophagosome-lysosome fusion. These data suggest that vacuolin-1 activates RAB5A to block autophagosome-lysosome fusion. Vacuolin-1 and its analogs present a novel class of drug that can potently and reversibly modulate autophagy.
Collapse
Key Words
- ATG, autophagy-related
- BAF, bafilomycin A1
- CQ, chloroquine
- CTSB, cathepsin B
- CTSL, cathepsin L
- EGFR, epidermal growth factor receptor
- GFP, green fluorescent protein
- GPN, glycyl-l-phenylalanine 2-naphthylamide
- LAMP1, lysosomal-associated membrane protein 1
- Leup, leupeptin
- MAP1LC3, microtubule-associated protein 1 light chain 3
- MTOR, mechanistic target of rapamycin
- RAB5A
- RFP, red fluorescent protein
- autophagosomes
- endosomes
- lysosomes
- pH
- tfLC3, tandem fluorescence-tagged LC3
- vacuolin-1
Collapse
Affiliation(s)
- Yingying Lu
- a Department of Biomedical Sciences ; City University of Hong Kong ; Hong Kong , China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Lin J, Huang Z, Wu H, Zhou W, Jin P, Wei P, Zhang Y, Zheng F, Zhang J, Xu J, Hu Y, Wang Y, Li Y, Gu N, Wen L. Inhibition of autophagy enhances the anticancer activity of silver nanoparticles. Autophagy 2014; 10:2006-20. [PMID: 25484080 PMCID: PMC4502813 DOI: 10.4161/auto.36293] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/04/2014] [Accepted: 08/29/2014] [Indexed: 12/19/2022] Open
Abstract
Silver nanoparticles (Ag NPs) are cytotoxic to cancer cells and possess excellent potential as an antitumor agent. A variety of nanoparticles have been shown to induce autophagy, a critical cellular degradation process, and the elevated autophagy in most of these situations promotes cell death. Whether Ag NPs can induce autophagy and how it might affect the anticancer activity of Ag NPs has not been reported. Here we show that Ag NPs induced autophagy in cancer cells by activating the PtdIns3K signaling pathway. The autophagy induced by Ag NPs was characterized by enhanced autophagosome formation, normal cargo degradation, and no disruption of lysosomal function. Consistent with these properties, the autophagy induced by Ag NPs promoted cell survival, as inhibition of autophagy by either chemical inhibitors or ATG5 siRNA enhanced Ag NPs-elicited cancer cell killing. We further demonstrated that wortmannin, a widely used inhibitor of autophagy, significantly enhanced the antitumor effect of Ag NPs in the B16 mouse melanoma cell model. Our results revealed a novel biological activity of Ag NPs in inducing cytoprotective autophagy, and inhibition of autophagy may be a useful strategy for improving the efficacy of Ag NPs in anticancer therapy.
Collapse
Key Words
- ANXA5, annexin A5
- CASP3, caspase 3, apoptosis-related cysteine peptidase
- CTSB, cathepsin B
- DLS, dynamic light scattering
- DMEM, Dulbecco's Modified Eagle's medium
- EGFP-LC3, enhanced green fluorescent protein-tagged LC3
- I-MEF, immortalized mouse embryonic fibroblast
- ICP-MS, inductively coupled plasma-mass spectrometry
- MDC, monodansylcadaverine
- MTOR, mechanistic target of rapamycin
- P-MEF, primary mouse embryonic fibroblast
- PI, propidium iodide
- PI3K, phosphoinositide 3-kinase
- PVP, polyvinylpyrrolidone
- PtdIns3K, phosphatidylinositol 3-kinase
- RPS6KB, ribosomal protein S6 kinase, 70 kDa
- SQSTM1, sequestosome 1
- TEM, transmission electron microscopy
- TUNEL, terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick end labeling
- UV-Vis, ultraviolet visible
- XRD, X-ray diffraction
- autophagy
- autophagy inhibition
- lysosomal function
- s.c., subcutaneously
- silver nanoparticles (Ag NPs)
- tumor therapy
Collapse
Affiliation(s)
- Jun Lin
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Zhihai Huang
- State Key Laboratory of Bioelectronics; Jiangsu Key Laboratory for Biomaterials and Devices; School of Biological Science and Medical Engineering; Southeast University; Nanjing, China
| | - Hao Wu
- State Key Laboratory of Bioelectronics; Jiangsu Key Laboratory for Biomaterials and Devices; School of Biological Science and Medical Engineering; Southeast University; Nanjing, China
| | - Wei Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Peipei Jin
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Pengfei Wei
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Yunjiao Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Fang Zheng
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Jiqian Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Jing Xu
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Yi Hu
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Yanhong Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Yajuan Li
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Ning Gu
- State Key Laboratory of Bioelectronics; Jiangsu Key Laboratory for Biomaterials and Devices; School of Biological Science and Medical Engineering; Southeast University; Nanjing, China
| | - Longping Wen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| |
Collapse
|