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γKlotho is a novel marker and cell survival factor in a subset of triple negative breast cancers. Oncotarget 2016; 7:2611-28. [PMID: 26556877 PMCID: PMC4823059 DOI: 10.18632/oncotarget.6006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 10/04/2015] [Indexed: 12/31/2022] Open
Abstract
Over the last decade, breast cancer mortality has declined. However, triple negative breast cancer (TNBC) remains a challenging problem mostly due to early recurrence and lack of molecularly driven treatments. There is a critical need to identify subgroups of TNBC with common molecular features that can be therapeutically targeted. Here we show that in contrast to Klotho and βKlotho, the third member of the Klotho protein family, γKlotho, is overexpressed in more than 60% of TNBCs and correlates with poorer disease progression. Furthermore, we find that γKlotho is expressed in a subset of TNBC cell lines promoting cell growth. Importantly, we demonstrate that in these cells γKlotho is necessary for cell survival and that its depletion leads to constitutive ERK activation, cell cycle arrest and apoptosis. Interestingly, we observe increased oxidative stress in γKlotho-depleted cells suggesting that γKlotho enables cancer cells to cope with an oxidative environment and that cells become dependent on its expression to maintain this survival advantage. These findings indicate that γKlotho might be a potential marker for patients that would benefit from treatments that alter oxidative stress and constitutes a novel drug target for a subset of TN breast cancers.
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102
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Ding ZB, Fu XT, Shi YH, Zhou J, Peng YF, Liu WR, Shi GM, Gao Q, Wang XY, Song K, Jin L, Tian MX, Shen YH, Fan J. Lamp2a is required for tumor growth and promotes tumor recurrence of hepatocellular carcinoma. Int J Oncol 2016; 49:2367-2376. [PMID: 27840904 DOI: 10.3892/ijo.2016.3754] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/20/2016] [Indexed: 11/05/2022] Open
Abstract
Exploring the function of chaperone-mediated autophagy (CMA) in cancer has promoted progress in cancer treatment through the regulation of CMA pathways. However, CMA status and function in hepatocellular carcinoma (HCC) by focusing on the regulatory role of lyso-some-associated membrane protein type 2a (Lamp2a) remain to be clarified. We examined Lamp2a in a normal human liver cell line, 6 HCC cell lines, 10 normal liver samples as well as 42 HCC tissue and para-tumor tissues samples, and then validated it in 228 HCC patients to assess the relationship between Lamp2a and clinical prognosis. Gain and loss of Lamp2a function were also explored in HCC cell lines and xenograft models. Significantly lower level of Lamp2a expression was found in HCC cells and tissues compared with normal hepatic cells, para-tumor tissues and normal livers. Although no differences in HCC cell morphology or function were observed in relation to Lamp2a expression under normal culture or short-term starvation conditions, Lamp2a blockage significantly inhibited HCC cell viability under prolonged starvation. Critically, Lamp2a is required for HCC xenograft growth in vivo by helping cells to avoid apoptosis and promoting cell proliferation. Furthermore, a significant correlation between Lamp2a expression and tumor size or cumulative recurrence was uncovered in HCC patients. Collectively, the present study shows that impaired Lamp2a expression in HCC contributes to tumor cell viability and promotes tumor growth and recurrence. Targeting chaperone-mediated autophagy through Lamp2a may also imply a potentially novel treatment strategy for HCC.
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Affiliation(s)
- Zhen-Bin Ding
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Xiu-Tao Fu
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Ying-Hong Shi
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Jian Zhou
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Yuan-Fei Peng
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Wei-Ren Liu
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Guo-Ming Shi
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Qiang Gao
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Xiao-Ying Wang
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Kang Song
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Lei Jin
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Meng-Xin Tian
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Ying-Hao Shen
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
| | - Jia Fan
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai 200032, P.R. China
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Morell C, Bort A, Vara-Ciruelos D, Ramos-Torres Á, Altamirano-Dimas M, Díaz-Laviada I, Rodríguez-Henche N. Up-Regulated Expression of LAMP2 and Autophagy Activity during Neuroendocrine Differentiation of Prostate Cancer LNCaP Cells. PLoS One 2016; 11:e0162977. [PMID: 27627761 PMCID: PMC5023108 DOI: 10.1371/journal.pone.0162977] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/31/2016] [Indexed: 11/18/2022] Open
Abstract
Neuroendocrine (NE) prostate cancer (PCa) is a highly aggressive subtype of prostate cancer associated with resistance to androgen ablation therapy. In this study, we used LNCaP prostate cancer cells cultured in a serum-free medium for 6 days as a NE model of prostate cancer. Serum deprivation increased the expression of NE markers such as neuron-specific enolase (NSE) and βIII tubulin (βIII tub) and decreased the expression of the androgen receptor protein in LNCaP cells. Using cDNA microarrays, we compared gene expression profiles of NE cells and non-differentiated LNCaP cells. We identified up-regulation of 155 genes, among them LAMP2, a lysosomal membrane protein involved in lysosomal stability and autophagy. We then confirmed up-regulation of LAMP2 in NE cells by qRT-PCR, Western blot and confocal microscopy assays, showing that mRNA up-regulation correlated with increased levels of LAMP2 protein. Subsequently, we determined autophagy activity in NE cells by assessing the protein levels of SQSTM/p62 and LC3 by Western blot and LC3 and Atg5 mRNAs content by qRT-PCR. The decreased levels of SQSTM/p62 was accompanied by an enhanced expression of LC3 and ATG5, suggesting activation of autophagy in NE cells. Blockage of autophagy with 1μM AKT inhibitor IV, or by silencing Beclin 1 and Atg5, prevented NE cell differentiation, as revealed by decreased levels of the NE markers. In addition, AKT inhibitor IV as well as Beclin1 and Atg5 kwockdown attenuated LAMP2 expression in NE cells. On the other hand, LAMP2 knockdown by siRNA led to a marked blockage of autophagy, prevention of NE differentiation and decrease of cell survival. Taken together, these results suggest that LAMP2 overexpression assists NE differentiation of LNCaP cells induced by serum deprivation and facilitates autophagy activity in order to attain the NE phenotype and cell survival. LAMP2 could thus be a potential biomarker and potential target for NE prostate cancer.
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Affiliation(s)
- Cecilia Morell
- Department of Systems Biology, Biochemistry and Molecular Biology Unit, School of Medicine and Health Sciences, University of Alcalá, Alcalá de Henares, Spain
| | - Alicia Bort
- Department of Systems Biology, Biochemistry and Molecular Biology Unit, School of Medicine and Health Sciences, University of Alcalá, Alcalá de Henares, Spain
| | - Diana Vara-Ciruelos
- Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Ágata Ramos-Torres
- Department of Systems Biology, Biochemistry and Molecular Biology Unit, School of Medicine and Health Sciences, University of Alcalá, Alcalá de Henares, Spain
| | | | - Inés Díaz-Laviada
- Department of Systems Biology, Biochemistry and Molecular Biology Unit, School of Medicine and Health Sciences, University of Alcalá, Alcalá de Henares, Spain
| | - Nieves Rodríguez-Henche
- Department of Systems Biology, Biochemistry and Molecular Biology Unit, School of Medicine and Health Sciences, University of Alcalá, Alcalá de Henares, Spain
- * E-mail:
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104
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Lee EJ, Park KS, Jeon IS, Choi JW, Lee SJ, Choy HE, Song KD, Lee HK, Choi JK. LAMP-3 (Lysosome-Associated Membrane Protein 3) Promotes the Intracellular Proliferation of Salmonella typhimurium. Mol Cells 2016; 39:566-72. [PMID: 27329040 PMCID: PMC4959022 DOI: 10.14348/molcells.2016.0112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/10/2016] [Accepted: 05/11/2016] [Indexed: 11/27/2022] Open
Abstract
Lysosomes are cellular organelles containing diverse classes of catabolic enzymes that are implicated in diverse cellular processes including phagocytosis, autophagy, lipid transport, and aging. Lysosome-associated membrane proteins (LAMP-1 and LAMP-2) are major glycoproteins important for maintaining lysosomal integrity, pH, and catabolism. LAMP-1 and LAMP-2 are constitutively expressed in Salmonella-infected cells and are recruited to Salmonella-containing vacuoles (SCVs) as well as Salmonella-induced filaments (Sifs) that promote the survival and proliferation of the Salmonella. LAMP-3, also known as DC-LAMP/CD208, is a member of the LAMP family of proteins, but its role during Salmonella infection remains unclear. DNA microarray analysis identified LAMP-3 as one of the genes responding to LPS stimulation in THP-1 macrophage cells. Subsequent analyses reveal that LPS and Salmonella induced the expression of LAMP-3 at both the transcriptional and translational levels. Confocal Super resolution N-SIM imaging revealed that LAMP-3, like LAMP-2, shifts its localization from the cell surface to alongside Salmonella. Knockdown of LAMP-3 by specific siRNAs decreased the number of Salmonella recovered from the infected cells. Therefore, we conclude that LAMP-3 is induced by Salmonella infection and recruited to the Salmonella pathogen for intracellular proliferation.
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Affiliation(s)
- Eun-Ju Lee
- Department of Biochemistry, College of Medicine, Chungbuk National University, Cheongju 28644,
Korea
| | - Kwan-Sik Park
- Department of Biochemistry, College of Medicine, Chungbuk National University, Cheongju 28644,
Korea
- Department of Animal Biotechnology, Chonbuk National University, Jeonju 54896,
Korea
| | - In-Sook Jeon
- Department of Biochemistry, College of Medicine, Chungbuk National University, Cheongju 28644,
Korea
| | - Jae-Woon Choi
- Department of Surgery, College of Medicine, Chungbuk National University, Cheongju 28644,
Korea
| | - Sang-Jeon Lee
- Department of Surgery, College of Medicine, Chungbuk National University, Cheongju 28644,
Korea
| | - Hyun E. Choy
- Department of Microbiology, Chonnam National University Medical School, Gwangju 61186,
Korea
| | - Ki-Duk Song
- Department of Animal Biotechnology, Chonbuk National University, Jeonju 54896,
Korea
| | - Hak-Kyo Lee
- Department of Animal Biotechnology, Chonbuk National University, Jeonju 54896,
Korea
| | - Joong-Kook Choi
- Department of Biochemistry, College of Medicine, Chungbuk National University, Cheongju 28644,
Korea
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105
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Su C, Yang X, Lou J. Geniposide reduces α-synuclein by blocking microRNA-21/lysosome-associated membrane protein 2A interaction in Parkinson disease models. Brain Res 2016; 1644:98-106. [PMID: 27173998 DOI: 10.1016/j.brainres.2016.05.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 05/05/2016] [Accepted: 05/07/2016] [Indexed: 12/22/2022]
Abstract
OBJECTIVE This study aimed to explore whether the regulatory effect of miR-21 on α-synuclein expression in neurons is a potential mechanism by which geniopside (GP) protects the central nervous system from Parkinson disease (PD). METHODS The human neuroblastoma cell line SH-SY5Y was induced to differentiate in vitro and treated with dimethyl sulfoxide (DMSO), N-methyl-4-phenylpyridinium iodide (MPP(+)), and MPP(+) together with GP. To identify the role of miR-21 in the regulation of lysosome-associated membrane protein 2 (LAMP2A) and α-synuclein, SH-SY5Y cells pretreated with MPP(+) were transfected with miR-21 mimic and miR-21 inhibitor. To identify whether GP could reduce the level of α-synuclein through miR-21/LAMP2A, SHSY5Y cells pretreated with GP were treated with miR-21 mimic or miR-21 inhibitor; meanwhile, a luciferase reporter assay was performed to confirm the direct target of miR-21. LAMP2A was overexpressed using a pCMV6-XL5-LAMP2A vector to confirm the role of LAMP2A in the regulation of α-synuclein by miR-21. In these in vitro experiments, the RNA and/or protein expressions of miR-21, LAMP2A, and α-synuclein in SH-SY5Y cells were determined by quantitative real-time polymerase chain reaction and/or western blotting, respectively. An in vivo PD mouse model was established through intraperitoneal injection with N-methyl-4-phenyl-l,2,3,6-tetrahydropyridine (MPTP). The mice were treated with saline, MPTP, MPTP+GP, and MPTP+GP+miR-21 agomir. The numbers of TH(+) cells in the substantia nigra in different groups of mice were compared. The RNA and/or protein expressions of miR-21, LAMP2A, and α-synuclein were also determined. RESULTS The level of miR-21 in the cells or mice models was significantly higher than that in normal cells or normal mice, respectively, and GP significantly downregulated miR-21. GP also raised the protein and mRNA expressions of LAMP2A and reduced the protein level of α-synuclein in PD models. MiR-21 upregulated the expression of α-synuclein by directly targeting 3' UTR of LAMP2A. LAMP2A overexpression abolished the upregulating effect of miR-21 mimic on α-synuclein. MiR-21 mimics/agomir reversed the GP-induced downregulation of α-synuclein; miR-21 inhibitor effectively increased the downregulation of α-synuclein caused by GP. CONCLUSION GP exhibits neuroprotective properties by inhibiting α-synuclein expression in PD models through the miR-21/LAMP2A axis.
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Affiliation(s)
- Chunhe Su
- Department of Neurology, Second Affiliated Hospital of Zhengzhou University, Zhengzhou 450014, Henan Province, China
| | - Xiaopeng Yang
- Department of Neurology, Second Affiliated Hospital of Zhengzhou University, Zhengzhou 450014, Henan Province, China
| | - Jiyu Lou
- Department of Neurology, Second Affiliated Hospital of Zhengzhou University, Zhengzhou 450014, Henan Province, China.
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106
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Tasset I, Cuervo AM. Role of chaperone-mediated autophagy in metabolism. FEBS J 2016; 283:2403-13. [PMID: 26854402 DOI: 10.1111/febs.13677] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 01/27/2016] [Accepted: 02/04/2016] [Indexed: 12/20/2022]
Abstract
Different types of autophagy coexist in most mammalian cells, and each of them fulfills very specific tasks in intracellular degradation. Some of these autophagic pathways contribute to cellular metabolism by directly hydrolyzing intracellular lipid stores and glycogen. Chaperone-mediated autophagy (CMA), in contrast, is a selective form of autophagy that can only target proteins for lysosomal degradation. Consequently, it was expected that the only possible contribution of this pathway to cellular metabolism would be by providing free amino acids resulting from protein breakdown. However, recent studies have demonstrated that disturbance in CMA leads to important alterations in glucose and lipid metabolism and in overall organism energetics. Here, we describe the unique mechanisms by which CMA contributes to the regulation of cellular metabolism and discuss the possible implications of these previously unknown functions of CMA for the pathogenesis of common metabolic diseases.
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Affiliation(s)
- Inmaculada Tasset
- Department of Developmental and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ana Maria Cuervo
- Department of Developmental and Molecular Biology, Institute for Aging Studies, Albert Einstein College of Medicine, Bronx, NY, USA
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107
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Expression of LC3, LAMP2, KEAP1 and NRF2 in Salivary Adenoid Cystic Carcinoma. Pathol Oncol Res 2015; 22:109-14. [PMID: 26350055 DOI: 10.1007/s12253-015-9981-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 09/01/2015] [Indexed: 10/23/2022]
Abstract
Salivary Adenoid Cystic Carcinoma (SACC) is a tumor characterized by inevitable local progression and terminal hematogenous metastasis. This study aimed to investigate the expression of LC3, LAMP2, KEAP1 and NRF2 in SACC. Human salivary gland tissue microarray which contains 74 SACC, 12 pleomorphic adenoma and 18 normal salivary gland specimens. High expression of LC3, LAMP2, KEAP1 and NRF2 were found in SACC patients, and LC3, LAMP2, KEAP1 and NRF2 expression were significantly higher in SACC than as compared with pleomorphic adenoma and (or) normal salivary gland. The expression of NRF2 was correlated with pathological type of human SACC (P < 0.05). Moreover, the high-expression of KEAP1 had significant correlations with LC3 (P < 0.001, R = 0.3195), and LAMP2 (P < 0.001, R = 0.3346) and NRF2 (P < 0.05, R = 0.2246) by using the Pearson correlation coefficient test. Our findings demonstrated that up-regulation of LC3, LAMP2, KEAP1 and NRF2 were associated with carcinogenesis and progression of SACC patients, suggesting that they may be useful molecular targets in salivary adenoid cystic carcinoma.
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108
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Li CL, Wei HL, Chen J, Wang B, Xie B, Fan LL, Li LJ. Ebb-and-flow of macroautophagy and chaperone-mediated autophagy in Raji cells induced by starvation and arsenic trioxide. Asian Pac J Cancer Prev 2015; 15:5715-9. [PMID: 25081691 DOI: 10.7314/apjcp.2014.15.14.5715] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Autophagy is crucial in the maintenance of homeostasis and regenerated energy of mammalian cells. Macroautophagy and chaperone-mediated autophagy(CMA) are the two best-identified pathways. Recent research has found that in normal cells, decline of macroautophagy is appropriately parallel with activation of CMA. However, whether it is also true in cancer cells has been poorly studied. Here we focused on cross-talk and conversion between macroautophagy and CMA in cultured Burkitt lymphoma Raji cells when facing serum deprivation and exposure to a toxic compound, arsenic trioxide. The results showed that both macroautophagy and CMA were activated sequentially instead of simultaneously in starvation-induced Raji cells, and macroautophagy was quickly activated and peaked during the first hours of nutrition deprivation, and then gradually decreased to near baseline. With nutrient deprivation persisted, CMA progressively increased along with the decline of macroautophagy. On the other hand, in arsenic trioxide-treated Raji cells, macroautophagy activity was also significantly increased, but CMA activity was not rapidly enhanced until macroautophagy was inhibited by 3-methyladenine, an inhibitor. Together, we conclude that cancer cells exhibit differential responses to diverse stressor-induced damage by autophagy. The sequential switch of the first-aider macroautophagy to the homeostasis-stabilizer CMA, whether active or passive, might be conducive to the adaption of cancer cells to miscellaneous intracellular or extracellular stressors. These findings must be helpful to understand the characteristics, compensatory mechanisms and answer modes of different autophagic pathways in cancer cells, which might be very important and promising to the development of potential targeting interventions for cancer therapies via regulation of autophagic pathways.
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Affiliation(s)
- Cai-Li Li
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China E-mail :
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109
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Rothaug M, Stroobants S, Schweizer M, Peters J, Zunke F, Allerding M, D’Hooge R, Saftig P, Blanz J. LAMP-2 deficiency leads to hippocampal dysfunction but normal clearance of neuronal substrates of chaperone-mediated autophagy in a mouse model for Danon disease. Acta Neuropathol Commun 2015; 3:6. [PMID: 25637286 PMCID: PMC4359523 DOI: 10.1186/s40478-014-0182-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 12/30/2014] [Indexed: 12/30/2022] Open
Abstract
The Lysosomal Associated Membrane Protein type-2 (LAMP-2) is an abundant lysosomal membrane protein with an important role in immunity, macroautophagy (MA) and chaperone-mediated autophagy (CMA). Mutations within the Lamp2 gene cause Danon disease, an X-linked lysosomal storage disorder characterized by (cardio)myopathy and intellectual dysfunction. The pathological hallmark of this disease is an accumulation of glycogen and autophagic vacuoles in cardiac and skeletal muscle that, along with the myopathy, is also present in LAMP-2-deficient mice. Intellectual dysfunction observed in the human disease suggests a pivotal role of LAMP-2 within brain. LAMP-2A, one specific LAMP-2 isoform, was proposed to be important for the lysosomal degradation of selective proteins involved in neurodegenerative diseases such as Huntington’s and Parkinson’s disease. To elucidate the neuronal function of LAMP-2 we analyzed knockout mice for neuropathological changes, MA and steady-state levels of CMA substrates. The absence of LAMP-2 in murine brain led to inflammation and abnormal behavior, including motor deficits and impaired learning. The latter abnormality points to hippocampal dysfunction caused by altered lysosomal activity, distinct accumulation of p62-positive aggregates, autophagic vacuoles and lipid storage within hippocampal neurons and their presynaptic terminals. The absence of LAMP-2 did not apparently affect MA or steady-state levels of selected CMA substrates in brain or neuroblastoma cells under physiological and prolonged starvation conditions. Our data contribute to the understanding of intellectual dysfunction observed in Danon disease patients and highlight the role of LAMP-2 within the central nervous system, particularly the hippocampus.
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110
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Oridonin phosphate-induced autophagy effectively enhances cell apoptosis of human breast cancer cells. Med Oncol 2014; 32:365. [PMID: 25491140 DOI: 10.1007/s12032-014-0365-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 11/13/2014] [Indexed: 01/08/2023]
Abstract
Oridonin is an active diterpenoid, which was extracted from traditional Chinese herbs and had been widely used in clinical treatment nowadays. Oridonin phosphate is one of the derivatives of oridonin. In the present study, we explored its anti-tumor effect and investigated the molecular mechanism of oridonin phosphate in breast cancer cell lines. Firstly, cell viability was analyzed by MTT assay. The breast cancer cells were treated with increasing concentrations of oridonin phosphate for 24, 48 and 72 h, respectively. The results demonstrated that oridonin phosphate inhibited the proliferation of MDA-MB-436 and MDA-MB-231 cells in a dose- and time-dependent manner. Next, cell apoptosis rate was detected in oridonin phosphate-treated breast cancer cells by Annexin V-FITC/PI dual staining analysis and the data demonstrated that oridonin phosphate induced cell apoptosis of breast cancer cells in time- and dose-dependent manner. Moreover, apoptosis-related proteins were detected by Western blotting analysis. The results showed that the expression level of Bax was up-regulated and the expression level of Bcl-2 was down-regulated. Meanwhile, the level of cleaved caspase-9 was significantly increased when the cells were treated with 40 μM of oridonin phosphate for 48 h, although the expression level of pro-caspase-9 was not obviously changed. All of the data revealed that mitochondrial apoptosis pathway may be involved in the cell apoptosis induced by oridonin phosphate in breast cancer cells. Importantly, the expression levels of autophagy-related protein beclin-1 and LC3-II were significantly higher in oridonin phosphate-treated breast cancer cell lines MDA-MB-436 and MDA-MB-231 for 48 h. Additionally, we further explored the relationship between apoptosis and autophagy specifically induced by oridonin phosphate in breast cancer cells. The result showed that inhibition of autophagy suppressed the cell apoptosis in oridonin phosphate-treated MDA-MB-436 cells. Taken together, the compound of oridonin phosphate simultaneously induced cell apoptosis and autophagy in breast cancer cells. Inhibition oridonin phosphate-induced cell autophagy suppressed the progression of cell apoptosis, which revealed that oridonin phosphate-induced autophagy participated in up-regulation of apoptosis in human breast cancer cells. It would provide some new clues for the therapy of breast cancer.
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111
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Chen GY, Chen CL, Tuan HY, Yuan PX, Li KC, Yang HJ, Hu YC. Graphene oxide triggers toll-like receptors/autophagy responses in vitro and inhibits tumor growth in vivo. Adv Healthc Mater 2014; 3:1486-95. [PMID: 24652749 DOI: 10.1002/adhm.201300591] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/24/2014] [Indexed: 11/10/2022]
Abstract
Graphene oxide (GO) is a nanomaterial with burgeoning bioapplications, while autophagy is implicated in cancer therapy. Although induction of autophagy by nanomaterials is reported, the underlying signaling mechanism in cancer cells and how this implicates the potential of GO in cancer therapy remain obscure. Here, it is shown that GO itself can induce the toll-like receptors (TLRs) responses and autophagy in cancer cells and confer antitumor effects in mice. GO can be phagocytosed by CT26 colon cancer cells, simultaneously triggering autophagy as well as TLR-4 and TLR-9 signaling cascades. By dissecting the crosstalk between the TLRs and autophagy pathways, it is uncovered that the GO-activated autophagy is regulated through the myeloid differentiation primary response gene 88 (MyD88)- and TNF receptor-associated factor 6 (TRAF6)-associated TLR-4/9 signaling pathways. Injection of GO alone into immunocompetent mice bearing the CT26 colon tumors not only suppresses the tumor progression but also enhances cell death, autophagy, and immune responses within the tumor bed. These data altogether implicate the potential of GO as an effective nanomaterial for autophagy induction and cancer therapy.
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Affiliation(s)
- Guan-Yu Chen
- Department of Chemical Engineering; National Tsing Hua University; Hsinchu Taiwan 300
| | - Chiu-Ling Chen
- Department of Chemical Engineering; National Tsing Hua University; Hsinchu Taiwan 300
| | - Hsing-Yu Tuan
- Department of Chemical Engineering; National Tsing Hua University; Hsinchu Taiwan 300
| | - Pei-Xiang Yuan
- Department of Chemical Engineering; National Tsing Hua University; Hsinchu Taiwan 300
| | - Kuei-Chang Li
- Department of Chemical Engineering; National Tsing Hua University; Hsinchu Taiwan 300
| | - Hong-Jie Yang
- Department of Chemical Engineering; National Tsing Hua University; Hsinchu Taiwan 300
| | - Yu-Chen Hu
- Department of Chemical Engineering; National Tsing Hua University; Hsinchu Taiwan 300
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112
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Zhang YB, Zhao W, Zeng RX. Autophagic degradation of caspase-8 protects U87MG cells against H2O2-induced oxidative stress. Asian Pac J Cancer Prev 2014; 14:4095-9. [PMID: 23991959 DOI: 10.7314/apjcp.2013.14.7.4095] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Oxidative stress induces apoptosis in many cellular systems including glioblastoma cells, with caspase-8 activation was regarded as a major contribution to H2O2-induced cell death. This study focused on the role of the autophagic protein p62 in H2O2-induced apoptosis in U87MG cells. Oxidative stress was applied with H2O2, and cell apoptosis and viability were measured with use of caspase inhibitors or autophagic mediators or siRNA p62, GFP-p62 and GFP-p62-UBA (del) transfection. We found that H2O2 -induced U87MG cell death was correlated with caspase-8. To understand the role of p62 in MG132-induced cell death, the levels of p62/SQSTM1 or autophagy in U87MG cells were modulated with biochemical or genetic methods. The results showed that the over-expression of wild type p62/SQSTM1 significantly reduced H2O2 induced cell death, but knockdown of p62 aggravated the process. In addition, inhibition of autophagy promoted p62 and active caspase-8 increasing H2O2 -induced apoptosis while induction of autophagy manifested the opposite effect. We further demonstrated that the function of p62/SQSTM1 required its C-terminus UBA domain to attenuate H2O2 cytotoxity by inhibition of caspase-8 activity. Our results indicated that p62/SQSTM1 was a potential contributor to mediate caspase-8 activation by autophagy in oxidative stress process.
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Affiliation(s)
- Yi-Bo Zhang
- Department of Pathogen Biology, School of Basic Medical Sciences, Liaoning Medical University, Jinzhou, China.
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113
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Abstract
Studies performed in the liver in the 1960s led to the identification of lysosomes and the discovery of autophagy, the process by which intracellular proteins and organelles are degraded in lysosomes. Early studies in hepatocytes also uncovered how nutritional status regulates autophagy and how various circulating hormones modulate the activity of this catabolic process in the liver. The intensive characterization of hepatic autophagy over the years has revealed that lysosome-mediated degradation is important not only for maintaining liver homeostasis in normal physiological conditions, but also for an adequate response of this organ to stressors such as proteotoxicity, metabolic dysregulation, infection and carcinogenesis. Autophagic malfunction has also been implicated in the pathogenesis of common liver diseases, suggesting that chemical manipulation of this process might hold potential therapeutic value. In this Review--intended as an introduction to the topic of hepatic autophagy for clinical scientists--we describe the different types of hepatic autophagy, their role in maintaining homeostasis in a healthy liver and the contribution of autophagic malfunction to liver disease.
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Abstract
This review focuses on chaperone-mediated autophagy (CMA), one of the proteolytic systems that contributes to degradation of intracellular proteins in lysosomes. CMA substrate proteins are selectively targeted to lysosomes and translocated into the lysosomal lumen through the coordinated action of chaperones located at both sides of the membrane and a dedicated protein translocation complex. The selectivity of CMA permits timed degradation of specific proteins with regulatory purposes supporting a modulatory role for CMA in enzymatic metabolic processes and subsets of the cellular transcriptional program. In addition, CMA contributes to cellular quality control through the removal of damaged or malfunctioning proteins. Here, we describe recent advances in the understanding of the molecular dynamics, regulation and physiology of CMA, and discuss the evidence in support of the contribution of CMA dysfunction to severe human disorders such as neurodegeneration and cancer.
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115
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Ma B, Liang LZ, Liao GQ, Liang YJ, Liu HC, Zheng GS, Su YX. Inhibition of autophagy enhances cisplatin cytotoxicity in human adenoid cystic carcinoma cells of salivary glands. J Oral Pathol Med 2013; 42:774-80. [PMID: 23590333 DOI: 10.1111/jop.12066] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2013] [Indexed: 12/14/2022]
Abstract
BACKGROUND The relationship between autophagy and chemotherapy in cancer has been studied a lot recent years. However, there is currently no study on the role of autophagy in chemotherapy of adenoid cystic carcinoma (ACC) of human salivary glands. We hypothesized that autophagy plays a protective role for human salivary gland ACC cells during chemotherapy, diminishes the effect of treatment, and ultimately results in poor sensitivity to chemotherapy. MATERIALS AND METHODS After inhibition of autophagy by 5 mM 3-methyladenine (3MA), 20 μM Chloroquine (CQ), or Beclin-1 shRNA, we examined the sensitivity of human salivary gland ACC cells to different concentrations of cis-diamminedichloroplatinum (CDDP) using MTT assay. Also, levels of autophagy in ACC cells treated by CDDP were assessed by western blot, GFP-LC3 fluorescence and transmission electron microscopy (TEM). RESULTS Inhibition of autophagy induced by 3MA, CQ, or Beclin-1 shRNA could all enhance human salivary gland ACC cell death treated by CDDP. And, levels of autophagy in these cells showed a significant increase after treated by CDDP. CONCLUSION Autophagy played a protective role for human salivary gland ACC cells during CDDP chemotherapy. Inhibition of autophagy in these cells could enhance cisplatin cytotoxicity-effects. These findings indicate a novel and promising way to reduce chemotherapy resistance and improve treatment outcome in human salivary gland ACC.
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Affiliation(s)
- Ben Ma
- Department of Oral and Maxillofacial Surgery, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China
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