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Han Y, Liu Y, Zhen J, Hou S, Zhang B, Cui Z, Wan Q, Feng H. P53 regulates mitochondrial biogenesis via transcriptionally induction of mitochondrial ribosomal protein L12. Exp Cell Res 2022; 418:113249. [PMID: 35691378 DOI: 10.1016/j.yexcr.2022.113249] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 11/16/2022]
Abstract
The well-documented tumor suppressor p53 is also a major stress response factor for its diverse regulation on cellular energetics. However, the effect of p53 on mitochondrial biogenesis, which plays a predominant role in response to the elevated energy demands, appears to be pleiotropic in various conditions and has not reached agreement. Mitochondrial ribosomal protein L12 (MRPL12), reported as a bi-functional protein for its roles in both mitochondrial ribosomes and transcriptional complexes, is a core regulatory component in mitochondrial biogenesis. Here we proved that MRPL12 is transcriptionally regulated by p53. Furthermore, the p53/MRPL12 regulation of mitochondria is part of the signaling pathway that maintains the basal mitochondrial content and positively coordinates the mitochondrial biogenesis and oxidative phosphorylation (OXPHOS) in response to metabolic perturbation. Since p53 serves as the'Guardian of the Genome', our findings may revealed a new mechanism underlying the conditions when more ATP is warranted to maintain the genome integrity and cell survival. Therefore the pharmacological intervention or metabolic modulation (e.g., through fasting or exercise) of the p53/MRPL12 pathway promises to be a therapeutic approach that can safeguard health.
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Affiliation(s)
- Yitong Han
- Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China; Department of Critical Care Medicine, Zibo First Hospital, Weifang Medical University, Zibo, Shandong, China
| | - Yi Liu
- Department of Pulmonary and Critical Care Medicine, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, 250021, China; Department of Pulmonary and Critical Care Medicine, Shandong Provincial Hospidhandongtal Affiliated to Shandong First Medical University, Jinan, Shandong, 250021, China; Shandong Key Laboratory of Infectious Respiratory Disease, Jinan, Shandong, 250021, China
| | - Junhui Zhen
- Qilu Hospital, Shandong University, Jinan, Shandong, China
| | - Shaoshuai Hou
- Department of Endocrinology, Shandong Provincial Hospital, Shandong First Medical University, Jinan, Shandong, China
| | - Bo Zhang
- Department of Endocrinology, Shandong Provincial Hospital, Shandong First Medical University, Jinan, Shandong, China
| | - ZhengGuo Cui
- Department of Environmental Health, University of Fukui School of Medical Science, University of Fukui, Fukui, Japan
| | - Qiang Wan
- Department of Cell Metabolism and Disease Laboratory, Jinan Central Hospital, Qilu Medical College, Shandong University, Jinan, 250012, China.
| | - Hong Feng
- Cancer Center, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
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2
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Silencing of AURKA augments the antitumor efficacy of the AURKA inhibitor MLN8237 on neuroblastoma cells. Cancer Cell Int 2020; 20:9. [PMID: 31920463 PMCID: PMC6947931 DOI: 10.1186/s12935-019-1072-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 12/13/2019] [Indexed: 12/30/2022] Open
Abstract
Background Aurora kinase A (AURKA) has been implicated in the regulation of cell cycle progression, mitosis and a key number of oncogenic signaling pathways in various malignancies including neuroblastoma. Small molecule inhibitors of AURKA have shown potential, but still not as good as expected effects in clinical trials. Little is known about this underlying mechanism. Here, we evaluated the inhibitory effects of AURKA inhibitor MLN8237 on neuroblastoma cells to understand the potential mechanisms responsible for tumor therapy. Methods MLN8237 treatment on neuroblastoma cell line IMR32 was done and in vivo inhibitory effects were investigated using tumor xenograft model. Cellular senescence was evaluated by senescence-associated β-gal Staining assay. Flow cytometry was used to tested cell cycle arrest and cell apoptosis. Senescence-associated signal pathways were detected by western blot. CD133 microbeads and microsphere formation were used to separate and enrich CD133+ cells. AURKA small interfering RNA transfection was carried to downregulate AURKA level. Finally, the combination of MLN8237 treatment with AURKA small interfering RNA transfection were adopted to evaluate the inhibitory effect on neuroblastoma cells. Results We demonstrate that MLN8237, an inhibitor of AURKA, induces the neuroblastoma cell line IMR32 into cellular senescence and G2/M cell phase arrest. Inactivation of AURKA results in MYCN destabilization and inhibits cell growth in vitro and in a mouse model. Although MLN8237 inhibits AURKA kinase activity, it has almost no inhibitory effect on the AURKA protein level. By contrast, MLN8237 treatment leads to abnormal high expression of AURKA in vitro and in vivo. Knockdown of AURKA reduces cell survival. The combination of MLN8237 with AURKA small interfering RNA results in more profound inhibitory effects on neuroblastoma cell growth. Moreover, MLN8237 treatment followed by AURKA siRNA forces senescent cells into apoptosis via suppression of the Akt/Stat3 pathway. Conclusions The effect of AURKA-targeted inhibition of tumor growth plays roles in both the inactivation of AURKA activity and the decrease in the AURKA protein expression level.
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3
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Pan JA, Tang Y, Yu JY, Zhang H, Zhang JF, Wang CQ, Gu J. miR-146a attenuates apoptosis and modulates autophagy by targeting TAF9b/P53 pathway in doxorubicin-induced cardiotoxicity. Cell Death Dis 2019; 10:668. [PMID: 31511497 PMCID: PMC6739392 DOI: 10.1038/s41419-019-1901-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 07/30/2019] [Accepted: 08/08/2019] [Indexed: 12/03/2022]
Abstract
Clinical therapy of doxorubicin (DOX) is limited due to its cardiotoxicity. miR-146a was proved as a protective factor in many cardiovascular diseases, but its role in chronic DOX-induced cardiotoxicity is unclear. The objective of this study was to demonstrate the role of miR-146a in low-dose long-term DOX-induced cardiotoxicity. Experiments have shown that DOX intervention caused a dose-dependent and time-dependent cardiotoxicity involving the increased of apoptosis and dysregulation of autophagy. The cardiotoxicity was inhibited by overexpressed miR-146a and was more severe when miR-146a was downgraded. Further research proved that miR-146a targeted TATA-binding protein (TBP) associated factor 9b (TAF9b), a coactivator and stabilizer of P53, indirectly destroyed the stability of P53, thereby inhibiting apoptosis and improving autophagy in cardiomyocytes. Besides, miR-146a knockout mice were used for in vivo validation. In the DOX-induced model, miR-146a deficiency made it worse whether in cardiac function, cardiomyocyte apoptosis or basal level of autophagy, than wild-type. In conclusion, miR-146a partially reversed the DOX-induced cardiotoxicity by targeting TAF9b/P53 pathway to attenuate apoptosis and adjust autophagy levels.
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Affiliation(s)
- Jian-An Pan
- Department of Cardiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Yong Tang
- Department of Hematology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Jian-Ying Yu
- Department of Cardiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Hui Zhang
- Department of Cardiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Jun-Feng Zhang
- Department of Cardiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Chang-Qian Wang
- Department of Cardiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Jun Gu
- Department of Cardiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.
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4
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McDonnell SJ, Spiller DG, White MRH, Prior IA, Paraoan L. ER stress-linked autophagy stabilizes apoptosis effector PERP and triggers its co-localization with SERCA2b at ER-plasma membrane junctions. Cell Death Discov 2019; 5:132. [PMID: 31508245 PMCID: PMC6718399 DOI: 10.1038/s41420-019-0212-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/24/2019] [Accepted: 07/29/2019] [Indexed: 01/01/2023] Open
Abstract
Specific molecular interactions that underpin the switch between ER stress-triggered autophagy-mediated cellular repair and cellular death by apoptosis are not characterized. This study reports the unexpected interaction elicited by ER stress between the plasma membrane (PM)-localized apoptosis effector PERP and the ER Ca2+ pump SERCA2b. We show that the p53 effector PERP, which specifically induces apoptosis when expressed above a threshold level, has a heterogeneous distribution across the PM of un-stressed cells and is actively turned over by the lysosome. PERP is upregulated following sustained starvation-induced autophagy, which precedes the onset of apoptosis indicating that PERP protein levels are controlled by a lysosomal pathway that is sensitive to cellular physiological state. Furthermore, ER stress stabilizes PERP at the PM and induces its increasing co-localization with SERCA2b at ER–PM junctions. The findings highlight a novel crosstalk between pro-survival autophagy and pro-death apoptosis pathways and identify, for the first time, accumulation of an apoptosis effector to ER–PM junctions in response to ER stress.
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Affiliation(s)
- Samantha J McDonnell
- 1Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX UK
| | - David G Spiller
- 2Systems Microscopy Centre, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT UK
| | - Michael R H White
- 3School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT UK
| | - Ian A Prior
- 4Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, L69 3BX UK
| | - Luminita Paraoan
- 1Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX UK
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5
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Abstract
Rapamycin inhibits cell proliferation, yet preserves (re)-proliferative potential (RPP). RPP is a potential of quiescent cells that is lost in senescent cells. mTOR drives conversion from quiescence to senescence (geroconversion). By suppressing geroconversion, rapamycin preserves RPP. Geroconversion is characterized by proliferation-like levels of phospho-S6K/S6/4E-BP1 in nonproliferating cells arrested by p16 and/or p21. mTOR-driven geroconversion is associated with cellular hyperfunction, which in turn leads to organismal aging manifested by age-related diseases.
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6
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Song S, Wu S, Wang Y, Wang Z, Ye C, Song R, Song D, Ruan Y. 17β-estradiol inhibits human umbilical vascular endothelial cell senescence by regulating autophagy via p53. Exp Gerontol 2018; 114:57-66. [PMID: 30399406 DOI: 10.1016/j.exger.2018.10.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 10/30/2018] [Accepted: 10/30/2018] [Indexed: 12/13/2022]
Abstract
Vascular endothelial cell (VEC) senescence is an initiating factor in numerous cardiovascular diseases. Recent studies showed that 17β-estradiol (17β-E2), an estrogen with numerous biological activities such as inhibition of atherosclerosis, protects VECs from senescence. However, the effects of 17β-E2 on human umbilical VECs (HUVECs) remain unknown. This study investigated the anti-senescent effect of 17β-E2 on HUVECs and explored the underlying mechanism with respect to autophagy and p53 activity. First, rapamycin and 3-methyladenine were used to clarify the relationship between autophagy and senescence in HUVECs, and an inverse relationship was demonstrated. Next, the effect of 17β-E2 on H2O2-induced senescence of HUVECs was examined. Increased autophagy induced by 17β-E2 inhibited H2O2-induced senescence of HUVECs, increased cell viability, and maintained HUVEC morphology. 17β-E2 pre-treatment also decreased cell cycle arrest, decreased the dephosphorylation of Rb, decreased the production of ET-1, and increased the production of NO. Most importantly, 17β-E2 pre-treatment increased autophagy by activating p53 and its downstream effector p53-upregulated modulator of apoptosis (PUMA). Overall, our data indicate the critical role of autophagy in the anti-senescent effect of 17β-E2 on HUVECs.
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Affiliation(s)
- Shicong Song
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Saizhu Wu
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuyan Wang
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhiwei Wang
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Changxiong Ye
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Rui Song
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Dongqing Song
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yunjun Ruan
- Department of Gerontology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
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7
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Simabuco FM, Morale MG, Pavan IC, Morelli AP, Silva FR, Tamura RE. p53 and metabolism: from mechanism to therapeutics. Oncotarget 2018; 9:23780-23823. [PMID: 29805774 PMCID: PMC5955117 DOI: 10.18632/oncotarget.25267] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/06/2018] [Indexed: 11/25/2022] Open
Abstract
The tumor cell changes itself and its microenvironment to adapt to different situations, including action of drugs and other agents targeting tumor control. Therefore, metabolism plays an important role in the activation of survival mechanisms to keep the cell proliferative potential. The Warburg effect directs the cellular metabolism towards an aerobic glycolytic pathway, despite the fact that it generates less adenosine triphosphate than oxidative phosphorylation; because it creates the building blocks necessary for cell proliferation. The transcription factor p53 is the master tumor suppressor; it binds to more than 4,000 sites in the genome and regulates the expression of more than 500 genes. Among these genes are important regulators of metabolism, affecting glucose, lipids and amino acids metabolism, oxidative phosphorylation, reactive oxygen species (ROS) generation and growth factors signaling. Wild-type and mutant p53 may have opposing effects in the expression of these metabolic genes. Therefore, depending on the p53 status of the cell, drugs that target metabolism may have different outcomes and metabolism may modulate drug resistance. Conversely, induction of p53 expression may regulate differently the tumor cell metabolism, inducing senescence, autophagy and apoptosis, which are dependent on the regulation of the PI3K/AKT/mTOR pathway and/or ROS induction. The interplay between p53 and metabolism is essential in the decision of cell fate and for cancer therapeutics.
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Affiliation(s)
- Fernando M. Simabuco
- Laboratory of Functional Properties in Foods, School of Applied Sciences (FCA), Universidade de Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Mirian G. Morale
- Center for Translational Investigation in Oncology/LIM24, Instituto do Câncer do Estado de São Paulo (ICESP), São Paulo, Brazil
- Department of Radiology and Oncology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Isadora C.B. Pavan
- Laboratory of Functional Properties in Foods, School of Applied Sciences (FCA), Universidade de Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Ana P. Morelli
- Laboratory of Functional Properties in Foods, School of Applied Sciences (FCA), Universidade de Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Fernando R. Silva
- Laboratory of Functional Properties in Foods, School of Applied Sciences (FCA), Universidade de Campinas (UNICAMP), Limeira, São Paulo, Brazil
| | - Rodrigo E. Tamura
- Center for Translational Investigation in Oncology/LIM24, Instituto do Câncer do Estado de São Paulo (ICESP), São Paulo, Brazil
- Department of Radiology and Oncology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
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8
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Manai F, Azzalin A, Gabriele F, Martinelli C, Morandi M, Biggiogera M, Bozzola M, Comincini S. The In Vitro Effects of Enzymatic Digested Gliadin on the Functionality of the Autophagy Process. Int J Mol Sci 2018; 19:ijms19020635. [PMID: 29473905 PMCID: PMC5855857 DOI: 10.3390/ijms19020635] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/16/2018] [Accepted: 02/19/2018] [Indexed: 12/22/2022] Open
Abstract
Gliadin, the alcohol-soluble protein fraction of wheat, contains the factor toxic for celiac disease (CD), and its toxicity is not reduced by digestion with gastro-pancreatic enzymes. Importantly, it is proved that an innate immunity to gliadin plays a key role in the development of CD. The immune response induces epithelial stress and reprograms intraepithelial lymphocytes into natural killer (NK)-like cells, leading to enterocyte apoptosis and an increase in epithelium permeability. In this contribution, we have reported that in Caco-2 cells the administration of enzymatically digested gliadin (PT-gliadin) reduced significantly the expression of the autophagy-related marker LC3-II. Furthermore, electron and fluorescent microscope analysis suggested a compromised functionality of the autophagosome apparatus. The rescue of the dysregulated autophagy process, along with a reduction of PT-gliadin toxicity, was obtained with a starvation induction protocol and by 3-methyladenine administration, while rapamycin, a well-known autophagy inducer, did not produce a significant improvement in the clearance of extra- and intra-cellular fluorescent PT-gliadin amount. Altogether, our results highlighted the possible contribution of the autophagy process in the degradation and in the reduction of extra-cellular release of gliadin peptides and suggest novel molecular targets to counteract gliadin-induced toxicity in CD.
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Affiliation(s)
- Federico Manai
- Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy.
| | - Alberto Azzalin
- Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy.
| | - Fabio Gabriele
- Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy.
| | - Carolina Martinelli
- Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy.
| | - Martina Morandi
- Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy.
| | - Marco Biggiogera
- Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy.
| | - Mauro Bozzola
- Pediatrics and Adolescentology Unit, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS San Matteo, 27100 Pavia, Italy.
| | - Sergio Comincini
- Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy.
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9
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The ER stress regulator Bip mediates cadmium-induced autophagy and neuronal senescence. Sci Rep 2016; 6:38091. [PMID: 27905509 PMCID: PMC5131476 DOI: 10.1038/srep38091] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/03/2016] [Indexed: 12/25/2022] Open
Abstract
Autophagy is protective in cadmium (Cd)-induced oxidative damage. Endoplasmic reticulum (ER) stress has been shown to induce autophagy in a process requiring the unfolded protein response signalling pathways. Cd treatment significantly increased senescence in neuronal cells, which was aggravated by 3-MA or silencing of Atg5 and abolished by rapamycin. Cd increased expression of ER stress regulators Bip, chop, eIf2α, and ATF4, and activated autophagy as evidenced by upregulated LC3. Moreover, the ER stress inhibitor mithramycin inhibited the expression of ER stress protein chaperone Bip and blocked autophagic flux. Downregulating Bip significantly blocked the conversion of LC3-I to LC3-II, decreased LC3 puncta formation, and prevented the increase of senescence in PC12 cells. Interestingly, knocking down Bip regulated the expression of p-AMPK, p-AKT and p-s6k induced by Cd. BAPTA, a Bip inhibitor, decreased the expression of p-AMPK and LC3-II, but enhanced neuronal senescence. In addition, we found that siRNA for Bip enhanced GATA4 expression after 6 h Cd exposure in PC12 cells, while rapamycin treatment decreased GATA4 levels induced by 24 h Cd exposure. These results indicate that autophagy degraded GATA4 in a Bip-dependent way. Our findings suggest that autophagy regulated by Bip expression after ER stress suppressed Cd-induced neuronal senescence.
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10
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Affiliation(s)
- Xinbing Sui
- Department of Medical Oncology, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China.,Biomedical Research Center and Key Laboratory of Biotherapy of Zhejiang Province, Hangzhou, China
| | - Weidong Han
- Department of Medical Oncology, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China.,Biomedical Research Center and Key Laboratory of Biotherapy of Zhejiang Province, Hangzhou, China
| | - Hongming Pan
- Department of Medical Oncology, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China.,Biomedical Research Center and Key Laboratory of Biotherapy of Zhejiang Province, Hangzhou, China
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11
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Leontieva OV, Blagosklonny MV. Tumor promoter-induced cellular senescence: cell cycle arrest followed by geroconversion. Oncotarget 2015; 5:12715-27. [PMID: 25587030 PMCID: PMC4350340 DOI: 10.18632/oncotarget.3011] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 12/26/2014] [Indexed: 02/07/2023] Open
Abstract
Phorbol ester (PMA or TPA), a tumor promoter, can cause either proliferation or cell cycle arrest, depending on cellular context. For example, in SKBr3 breast cancer cells, PMA hyper-activates the MEK/MAPK pathway, thus inducing p21 and cell cycle arrest. Here we showed that PMA-induced arrest was followed by conversion to cellular senescence (geroconversion). Geroconversion was associated with active mTOR and S6 kinase (S6K). Rapamycin suppressed geroconversion, maintaining quiescence instead. In this model, PMA induced arrest (step one of a senescence program), whereas constitutively active mTOR drove geroconversion (step two). Without affecting Akt phosphorylation, PMA increased phosphorylation of S6K (T389) and S6 (S240/244), and that was completely prevented by rapamycin. Yet, T421/S424 and S235/236 (p-S6K and p-S6, respectively) phosphorylation became rapamycin-insensitive in the presence of PMA. Either MEK or mTOR was sufficient to phosphorylate these PMA-induced rapamycin-resistant sites because co-treatment with U0126 and rapamycin was required to abrogate them. We next tested whether activation of rapamycin-insensitive pathways would shift quiescence towards senescence. In HT-p21 cells, cell cycle arrest was caused by IPTG-inducible p21 and was spontaneously followed by mTOR-dependent geroconversion. Rapamycin suppressed geroconversion, whereas PMA partially counteracted the effect of rapamycin, revealing the involvement of rapamycin-insensitive gerogenic pathways. In normal RPE cells arrested by serum withdrawal, the mTOR/pS6 pathway was inhibited and cells remained quiescent. PMA transiently activated mTOR, enabling partial geroconversion. We conclude that PMA can initiate a senescent program by either inducing arrest or fostering geroconversion or both. Rapamycin can decrease gero-conversion by PMA, without preventing PMA-induced arrest. The tumor promoter PMA is a gero-promoter, which may be useful to study aging in mammals.
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Affiliation(s)
- Olga V Leontieva
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, NY, USA
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12
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Wang HL, Fan SS, Pang M, Liu YH, Guo M, Liang JB, Zhang JL, Yu BF, Guo R, Xie J, Zheng GP. The Ankyrin Repeat Domain 49 (ANKRD49) Augments Autophagy of Serum-Starved GC-1 Cells through the NF-κB Pathway. PLoS One 2015; 10:e0128551. [PMID: 26043108 PMCID: PMC4455995 DOI: 10.1371/journal.pone.0128551] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 04/28/2015] [Indexed: 11/18/2022] Open
Abstract
The ankyrin repeat domain 49 (ANKRD49) is an evolutionarily conserved protein highly expressed in testes. However, the function of ANKRD49 in spermatogenesis is unknown. In this study, we found that ANKRD49 resides primarily in nucleus of spermatogonia, spermatocytes and round spermatids. ANKRD49 overexpression augments starvation-induced autophagy in male germ GC-1 cells whereas shRNA knockdown of ANKRD49 attenuates the autophagy. Inhibition of NF-κB pathway by its inhibitors or p65 siRNA prevents the ANKRD49-dependent autophagy augmentation, demonstrating that ANKRD49 enhances autophagy via NF-κB pathway. Our findings suggest that ANKRD49 plays an important role in spermatogenesis via promotion of autophagy-dependent survival.
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Affiliation(s)
- Hai-long Wang
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Sha-sha Fan
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Min Pang
- Department of Respiratory, the First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Yi-heng Liu
- Class 041002, Department of Anestesioloy, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Min Guo
- Center of Laboratory Animal, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Jun-bo Liang
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Tsinghua University, 5 Dong Dan San Tiao, Beijing, 100005, China
| | - Jian-lin Zhang
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Bao-feng Yu
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
| | - Rui Guo
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
- * E-mail: (RG); (JX); (GPZ)
| | - Jun Xie
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
- * E-mail: (RG); (JX); (GPZ)
| | - Guo-ping Zheng
- Department of Biochemistry and Molecular Biology, Shanxi Medical University, Taiyuan, Shanxi, 030001, PR China
- * E-mail: (RG); (JX); (GPZ)
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13
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Abstract
Apoptosis and autophagy are both highly regulated biological processes that have important roles in development, differentiation, homeostasis, and disease. These processes may take place independently, with autophagy being cytoprotective for preventing cells from apoptosis and apoptosis blocking autophagy. But in most circumstances, both may be induced sequentially with autophagy preceding apoptosis. The simultaneous activation of both processes has been observed not only in experimental settings but also in pathophysiological conditions. In fact, these two pathways are tightly connected with each other by substantial interplays between them, enabling the coordinated regulation of cell fates by these two pathways. They share some common upstream signaling components, and some components of one pathway may play important roles in the other, and vice versa. Such proteins represent the critical interconnections of the two pathways, which seem to determine the cell for survival or death. Here several critical molecular interconnections between apoptosis and autophagy pathways are reviewed, with their action mechanisms being highlighted.
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Affiliation(s)
- Gao-Xiang Zhao
- Department of Immunobiology, College of Life Science and Technology, Jinan University , Guangzhou 510632 , China
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