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Wu C, Hu L, Liu B, Zeng X, Ma H, Cao Y, Li H, Zhang X. TRAF6-mediated ubiquitination of AKT in the nucleus is a critical event underlying the desensitization of G protein-coupled receptors. Cell Commun Signal 2024; 22:213. [PMID: 38566235 PMCID: PMC10986131 DOI: 10.1186/s12964-024-01592-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 03/23/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Desensitization of G protein-coupled receptors (GPCRs) refers to the attenuation of receptor responsiveness by prolonged or intermittent exposure to agonists. The binding of β-arrestin to the cytoplasmic cavity of the phosphorylated receptor, which competes with the G protein, has been widely accepted as an extensive model for explaining GPCRs desensitization. However, studies on various GPCRs, including dopamine D2-like receptors (D2R, D3R, D4R), have suggested the existence of other desensitization mechanisms. The present study employed D2R/D3R variants with different desensitization properties and utilized loss-of-function approaches to uncover the mechanisms underlying GPCRs homologous desensitization, focusing on the signaling cascade that regulates the ubiquitination of AKT. RESULTS AKT undergoes K8/14 ubiquitination by TRAF6, which occurs in the nucleus and promotes its membrane recruitment, phosphorylation and activation under receptor desensitization conditions. The nuclear entry of TRAF6 relies on the presence of the importin complex. Src regulates the nuclear entry of TRAF6 by mediating the interaction between TRAF6 and importin β1. Ubiquitinated AKT translocates to the plasma membrane where it associates with Mdm2 to phosphorylate it at the S166 and S186 residues. Thereafter, phosphorylated Mdm2 is recruited to the nucleus, resulting in the deubiquitination of β-Arr2. The deubiquitinated β-Arr2 then forms a complex with Gβγ, which serves as a biomarker for GPCRs desensitization. Like in D3R, ubiquitination of AKT is also involved in the desensitization of β2 adrenoceptors. CONCLUSION Our study proposed that the property of a receptor that causes a change in the subcellular localization of TRAF6 from the cytoplasm to the nucleus to mediate AKT ubiquitination could initiate the desensitization of GPCRs.
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Affiliation(s)
- Chengyan Wu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Li Hu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Bing Liu
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Xingyue Zeng
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Haixiang Ma
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China
| | - Yongkai Cao
- Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University, Shenzhen, 518035, China
| | - Huijun Li
- Department of Pharmaceuticals, People's Hospital of Zunyi City Bo Zhou District, Zunyi, 563000, China
| | - Xiaohan Zhang
- School of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025, China.
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2
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Zhang Y, Yang YS, Chen WC, Wang CM, He HF. Constructing and Validating a Network of Potential Olfactory Sheathing Cell Transplants Regulating Spinal Cord Injury Progression. Mol Neurobiol 2023; 60:6883-6895. [PMID: 37515671 DOI: 10.1007/s12035-023-03510-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 07/10/2023] [Indexed: 07/31/2023]
Abstract
The pathology of spinal cord injury (SCI), including primary and secondary injuries, primarily involves hemorrhage, ischemia, edema, and inflammatory responses. Cell transplantation has been the most promising treatment for SCI in recent years; however, its specific molecular mechanism remains unclear. In this study, bioinformatics analysis verified by experiment was used to elucidate the hub genes associated with SCI and to discover the underlying molecular mechanisms of cell intervention. GSE46988 data were downloaded from the Gene Expression Omnibus dataset. In our study, differentially expressed genes (DEGs) were reanalyzed using the "R" software (R v4.2.1). Functional enrichment and protein-protein interaction network analyses were performed, and key modules and hub genes were identified. Network construction was performed for the hub genes and their associated miRNAs. Finally, a semi-quantitative analysis of hub genes and pathways was performed using quantitative real-time polymerase chain reaction. In total, 718 DEGs were identified, mainly enriched in immune and inflammation-related functions. We found that Cd4, Tp53, Rac2, and Akt3 differed between vehicle and transplanted groups, suggesting that these genes may play an essential role in the transplantation of olfactory ensheathing cells, while a toll-like receptor signaling pathway was significantly enriched in Gene set enrichment analysis, and then, the differences were statistically significant by experimentally verifying the expression of their associated molecules (Tlr4, Nf-κb, Ikkβ, Cxcl2, and Tnf-α). In addition, we searched for upstream regulatory molecules of these four central genes and constructed a regulatory network. This study is the first to construct a regulatory network for olfactory ensheathing cell transplantation in treating SCI, providing a new idea for SCI cell therapy.
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Affiliation(s)
- Yan Zhang
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, China
| | - Yu-Shen Yang
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, China
| | - Wei-Can Chen
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, China
| | - Cong-Mei Wang
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, China
| | - He-Fan He
- Department of Anesthesiology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian Province, China.
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3
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Deng RM, Zhou J. The role of PI3K/AKT signaling pathway in myocardial ischemia-reperfusion injury. Int Immunopharmacol 2023; 123:110714. [PMID: 37523969 DOI: 10.1016/j.intimp.2023.110714] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 07/09/2023] [Accepted: 07/24/2023] [Indexed: 08/02/2023]
Abstract
Myocardial ischemia has a high incidence and mortality rate, and reperfusion is currently the standard intervention. However, reperfusion may lead to further myocardial damage, known as myocardial ischemia/reperfusion injury (MIRI). There are currently no effective clinical treatments for MIRI. The PI3K/Akt signaling pathway is involved in cardiovascular health and disease and plays an important role in reducing myocardial infarct size and restoring cardiac function after MIRI. Activation of the PI3K/Akt pathway provides myocardial protection through synergistic upregulation of antioxidant, anti-inflammatory, and autophagy activities and inhibition of mitochondrial dysfunction and cardiomyocyte apoptosis. Many studies have shown that PI3K/Akt has a significant protective effect against MIRI. Here, we reviewed the molecular regulation of PI3K/Akt in MIRI and summarized the molecular mechanism by which PI3K/Akt affects MIRI, the effects of ischemic preconditioning and ischemic postconditioning, and the role of related drugs or activators targeting PI3K/Akt in MIRI, providing novel insights for the formulation of myocardial protection strategies. This review provides evidence of the role of PI3K/Akt activation in MIRI and supports its use as a therapeutic target.
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Affiliation(s)
- Rui-Ming Deng
- Department of Anesthesiology, Ganzhou People's Hospital, 16 Meiguan Avenue, Ganzhou, Jiangxi Province 341000, PR China; The Affiliated Ganzhou Hospital of Nanchang University, 16 Meiguan Avenue, Ganzhou, Jiangxi Province 341000, PR China
| | - Juan Zhou
- Department of thyroid and Breast Surgery, Ganzhou People's Hospital, 16 Meiguan Avenue, Ganzhou, Jiangxi Province 341000, PR China; The Affiliated Ganzhou Hospital of Nanchang University, 16 Meiguan Avenue, Ganzhou, Jiangxi Province 341000, PR China.
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4
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Tao Y, Luo W, Chen Y, Chen C, Chen S, Li X, Chen K, Zeng C. Exercise ameliorates skeletal muscle insulin resistance by modulating GRK4-mediated D1R expression. Clin Sci (Lond) 2023; 137:1391-1407. [PMID: 37622333 DOI: 10.1042/cs20230664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/24/2023] [Accepted: 08/24/2023] [Indexed: 08/26/2023]
Abstract
Exercise has been recommended as a nonpharmaceutical therapy to treat insulin resistance (IR). Previous studies showed that dopamine D1-like receptor agonists, such as fenoldopam, could improve peripheral insulin sensitivity, while antipsychotics, which are dopamine receptor antagonists, increased susceptibility to Type 2 diabetes mellitus (T2DM). Meanwhile, exercise has been proved to stimulate dopamine receptors. However, whether the dopamine D1 receptor (D1R) is involved in exercise-mediated amelioration of IR remains unclear. We found that the D1-like receptor antagonist, SCH23390, reduced the effect of exercise on lowering blood glucose and insulin in insulin-resistant mice and inhibited the contraction-induced glucose uptake in C2C12 myotubes. Similarly, the opposite was true for the D1-like receptor agonist, fenoldopam. Furthermore, the expression of D1R was decreased in skeletal muscles from streptozotocin (STZ)- and high-fat intake-induced T2DM mice, accompanied by increased D1R phosphorylation, which was reversed by exercise. A screening study showed that G protein-coupled receptor kinase 4 (GRK4) may be the candidate kinase for the regulation of D1R function, because, in addition to the increased GRK4 expression in skeletal muscles of T2DM mice, GRK4 transgenic T2DM mice exhibited lower insulin sensitivity, accompanied by higher D1R phosphorylation than control mice, whereas the AAV9-shGRK4 mice were much more sensitive to insulin than AAV9-null mice. Mechanistically, the up-regulation of GRK4 expression caused by increased reactive oxygen species (ROS) in IR was ascribed to the enhanced expression of c-Myc, a transcriptional factor of GRK4. Taken together, the present study shows that exercise, via regulation of ROS/c-Myc/GRK4 pathway, ameliorates D1R dysfunction and improves insulin sensitivity.
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Affiliation(s)
- Yu Tao
- Department of Cardiology, Daping Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- Key Laboratory of Geriatric Cardiovascular and Cerebrovascular Disease Research, Ministry of Education of China, Chongqing Key Laboratory for Hypertension Research, Chongqing Cardiovascular Clinical Research Center, Chongqing Institute of Cardiology, Chongqing, China
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, China
| | - Wenbin Luo
- Department of Cardiology, Daping Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- Key Laboratory of Geriatric Cardiovascular and Cerebrovascular Disease Research, Ministry of Education of China, Chongqing Key Laboratory for Hypertension Research, Chongqing Cardiovascular Clinical Research Center, Chongqing Institute of Cardiology, Chongqing, China
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, China
| | - Yue Chen
- Department of Cardiology, Daping Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- Key Laboratory of Geriatric Cardiovascular and Cerebrovascular Disease Research, Ministry of Education of China, Chongqing Key Laboratory for Hypertension Research, Chongqing Cardiovascular Clinical Research Center, Chongqing Institute of Cardiology, Chongqing, China
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, China
| | - Caiyu Chen
- Department of Cardiology, Daping Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- Key Laboratory of Geriatric Cardiovascular and Cerebrovascular Disease Research, Ministry of Education of China, Chongqing Key Laboratory for Hypertension Research, Chongqing Cardiovascular Clinical Research Center, Chongqing Institute of Cardiology, Chongqing, China
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, China
| | - Shengnan Chen
- Department of Cardiology, Daping Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- Key Laboratory of Geriatric Cardiovascular and Cerebrovascular Disease Research, Ministry of Education of China, Chongqing Key Laboratory for Hypertension Research, Chongqing Cardiovascular Clinical Research Center, Chongqing Institute of Cardiology, Chongqing, China
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, China
| | - Xiaoping Li
- Department of Cardiology, Daping Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- Key Laboratory of Geriatric Cardiovascular and Cerebrovascular Disease Research, Ministry of Education of China, Chongqing Key Laboratory for Hypertension Research, Chongqing Cardiovascular Clinical Research Center, Chongqing Institute of Cardiology, Chongqing, China
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, China
| | - Ken Chen
- Department of Cardiology, Daping Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- Key Laboratory of Geriatric Cardiovascular and Cerebrovascular Disease Research, Ministry of Education of China, Chongqing Key Laboratory for Hypertension Research, Chongqing Cardiovascular Clinical Research Center, Chongqing Institute of Cardiology, Chongqing, China
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, China
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, Third Military Medical University (Army Medical University), Chongqing, China
- Key Laboratory of Geriatric Cardiovascular and Cerebrovascular Disease Research, Ministry of Education of China, Chongqing Key Laboratory for Hypertension Research, Chongqing Cardiovascular Clinical Research Center, Chongqing Institute of Cardiology, Chongqing, China
- State Key Laboratory of Trauma, Burns and Combined Injury, Daping Hospital, Army Medical University, Chongqing, China
- Cardiovascular Research Center of Chongqing College, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Chongqing, P.R. China
- Department of Cardiology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan Province, P.R. China
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5
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Ding Y, Chen Q. The NF-κB Pathway: a Focus on Inflammatory Responses in Spinal Cord Injury. Mol Neurobiol 2023; 60:5292-5308. [PMID: 37286724 DOI: 10.1007/s12035-023-03411-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 05/29/2023] [Indexed: 06/09/2023]
Abstract
Spinal cord injury (SCI) is a type of central nervous system trauma that can lead to severe nerve injury. Inflammatory reaction after injury is an important pathological process leading to secondary injury. Long-term stimulation of inflammation can further deteriorate the microenvironment of the injured site, leading to the deterioration of neural function. Understanding the signaling pathways that regulate responses after SCI, especially inflammatory responses, is critical for the development of new therapeutic targets and approaches. Nuclear transfer factor-κB (NF-κB) has long been recognized as a key factor in regulating inflammatory responses. The NF-κB pathway is closely related to the pathological process of SCI. Inhibition of this pathway can improve the inflammatory microenvironment and promote the recovery of neural function after SCI. Therefore, the NF-κB pathway may be a potential therapeutic target for SCI. This article reviews the mechanism of inflammatory response after SCI and the characteristics of NF-κB pathway, emphasizing the effect of inhibiting NF-κB on the inflammatory response of SCI to provide a theoretical basis for the biological treatment of SCI.
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Affiliation(s)
- Yi Ding
- Department of Spine Surgery, Ganzhou People's Hospital, 16 Meiguan Avenue, Ganzhou, Jiangxi Province, 341000, People's Republic of China
- The Affiliated Ganzhou Hospital of Nanchang University, 16 Meiguan Avenue, Ganzhou, Jiangxi Province, 341000, People's Republic of China
| | - Qin Chen
- Department of Spine Surgery, Ganzhou People's Hospital, 16 Meiguan Avenue, Ganzhou, Jiangxi Province, 341000, People's Republic of China.
- The Affiliated Ganzhou Hospital of Nanchang University, 16 Meiguan Avenue, Ganzhou, Jiangxi Province, 341000, People's Republic of China.
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6
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Candido MF, Medeiros M, Veronez LC, Bastos D, Oliveira KL, Pezuk JA, Valera ET, Brassesco MS. Drugging Hijacked Kinase Pathways in Pediatric Oncology: Opportunities and Current Scenario. Pharmaceutics 2023; 15:pharmaceutics15020664. [PMID: 36839989 PMCID: PMC9966033 DOI: 10.3390/pharmaceutics15020664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/18/2023] Open
Abstract
Childhood cancer is considered rare, corresponding to ~3% of all malignant neoplasms in the human population. The World Health Organization (WHO) reports a universal occurrence of more than 15 cases per 100,000 inhabitants around the globe, and despite improvements in diagnosis, treatment and supportive care, one child dies of cancer every 3 min. Consequently, more efficient, selective and affordable therapeutics are still needed in order to improve outcomes and avoid long-term sequelae. Alterations in kinases' functionality is a trademark of cancer and the concept of exploiting them as drug targets has burgeoned in academia and in the pharmaceutical industry of the 21st century. Consequently, an increasing plethora of inhibitors has emerged. In the present study, the expression patterns of a selected group of kinases (including tyrosine receptors, members of the PI3K/AKT/mTOR and MAPK pathways, coordinators of cell cycle progression, and chromosome segregation) and their correlation with clinical outcomes in pediatric solid tumors were accessed through the R2: Genomics Analysis and Visualization Platform and by a thorough search of published literature. To further illustrate the importance of kinase dysregulation in the pathophysiology of pediatric cancer, we analyzed the vulnerability of different cancer cell lines against their inhibition through the Cancer Dependency Map portal, and performed a search for kinase-targeted compounds with approval and clinical applicability through the CanSAR knowledgebase. Finally, we provide a detailed literature review of a considerable set of small molecules that mitigate kinase activity under experimental testing and clinical trials for the treatment of pediatric tumors, while discuss critical challenges that must be overcome before translation into clinical options, including the absence of compounds designed specifically for childhood tumors which often show differential mutational burdens, intrinsic and acquired resistance, lack of selectivity and adverse effects on a growing organism.
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Affiliation(s)
- Marina Ferreira Candido
- Department of Cell Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Mariana Medeiros
- Regional Blood Center, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - Luciana Chain Veronez
- Department of Pediatrics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - David Bastos
- Department of Biology, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-901, SP, Brazil
| | - Karla Laissa Oliveira
- Department of Biology, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-901, SP, Brazil
| | - Julia Alejandra Pezuk
- Departament of Biotechnology and Innovation, Anhanguera University of São Paulo, UNIAN/SP, São Paulo 04119-001, SP, Brazil
| | - Elvis Terci Valera
- Department of Pediatrics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil
| | - María Sol Brassesco
- Departament of Biotechnology and Innovation, Anhanguera University of São Paulo, UNIAN/SP, São Paulo 04119-001, SP, Brazil
- Correspondence: ; Tel.: +55-16-3315-9144; Fax: +55-16-3315-4886
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7
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The role of PI3K/Akt signalling pathway in spinal cord injury. Biomed Pharmacother 2022; 156:113881. [DOI: 10.1016/j.biopha.2022.113881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 10/13/2022] [Accepted: 10/13/2022] [Indexed: 11/18/2022] Open
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8
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Siddika T, Balasuriya N, Frederick MI, Rozik P, Heinemann IU, O’Donoghue P. Delivery of Active AKT1 to Human Cells. Cells 2022; 11:cells11233834. [PMID: 36497091 PMCID: PMC9738475 DOI: 10.3390/cells11233834] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/22/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022] Open
Abstract
Protein kinase B (AKT1) is a serine/threonine kinase and central transducer of cell survival pathways. Typical approaches to study AKT1 biology in cells rely on growth factor or insulin stimulation that activates AKT1 via phosphorylation at two key regulatory sites (Thr308, Ser473), yet cell stimulation also activates many other kinases. To produce cells with specific AKT1 activity, we developed a novel system to deliver active AKT1 to human cells. We recently established a method to produce AKT1 phospho-variants from Escherichia coli with programmed phosphorylation. Here, we fused AKT1 with an N-terminal cell penetrating peptide tag derived from the human immunodeficiency virus trans-activator of transcription (TAT) protein. The TAT-tag did not alter AKT1 kinase activity and was necessary and sufficient to rapidly deliver AKT1 protein variants that persisted in human cells for 24 h without the need to use transfection reagents. TAT-pAKT1T308 induced selective phosphorylation of the known AKT1 substrate GSK-3α, but not GSK-3β, and downstream stimulation of the AKT1 pathway as evidenced by phosphorylation of ribosomal protein S6 at Ser240/244. The data demonstrate efficient delivery of AKT1 with programmed phosphorylation to human cells, thus establishing a cell-based model system to investigate signaling that is dependent on AKT1 activity.
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Affiliation(s)
- Tarana Siddika
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Nileeka Balasuriya
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Mallory I. Frederick
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Peter Rozik
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Ilka U. Heinemann
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
- Correspondence: (I.U.H.); (P.O.)
| | - Patrick O’Donoghue
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
- Correspondence: (I.U.H.); (P.O.)
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9
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Chen M, Choi S, Wen T, Chen C, Thapa N, Lee JH, Cryns VL, Anderson RA. A p53-phosphoinositide signalosome regulates nuclear AKT activation. Nat Cell Biol 2022; 24:1099-1113. [PMID: 35798843 PMCID: PMC9833102 DOI: 10.1038/s41556-022-00949-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 05/26/2022] [Indexed: 01/13/2023]
Abstract
The tumour suppressor p53 and PI3K-AKT pathways have fundamental roles in the regulation of cell growth and apoptosis, and are frequently mutated in cancer. Here, we show that genotoxic stress induces nuclear AKT activation through a p53-dependent mechanism that is distinct from the canonical membrane-localized PI3K-AKT pathway. Following genotoxic stress, a nuclear PI3K binds p53 in the non-membranous nucleoplasm to generate a complex of p53 and phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3), which recruits AKT, PDK1 and mTORC2 to activate AKT and phosphorylate FOXO proteins, thereby inhibiting DNA damage-induced apoptosis. Wild-type p53 activates nuclear AKT in an on/off fashion following stress, whereas mutant p53 dose-dependently stimulates high basal AKT activity. The p53-PtdIns(3,4,5)P3 complex is dephosphorylated to p53-phosphatidylinositol 4,5-bisphosphate by PTEN to inhibit AKT activation. The nuclear p53-phosphoinositide signalosome is distinct from the canonical membrane-localized pathway and insensitive to PI3K inhibitors currently in the clinic, which underscores its therapeutic relevance.
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Affiliation(s)
- Mo Chen
- University of Wisconsin-Madison, School of Medicine and Public Health; 1300 University Avenue, Madison, WI 53706, USA
| | - Suyong Choi
- University of Wisconsin-Madison, School of Medicine and Public Health; 1300 University Avenue, Madison, WI 53706, USA
| | - Tianmu Wen
- University of Wisconsin-Madison, School of Medicine and Public Health; 1300 University Avenue, Madison, WI 53706, USA
| | - Changliang Chen
- University of Wisconsin-Madison, School of Medicine and Public Health; 1300 University Avenue, Madison, WI 53706, USA,Department of Medicine, University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, School of Medicine and Public Health; 1111 Highland Avenue, Madison, WI 53705, USA
| | - Narendra Thapa
- University of Wisconsin-Madison, School of Medicine and Public Health; 1300 University Avenue, Madison, WI 53706, USA
| | - Jeong Hyo Lee
- University of Wisconsin-Madison, School of Medicine and Public Health; 1300 University Avenue, Madison, WI 53706, USA,Department of Medicine, University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, School of Medicine and Public Health; 1111 Highland Avenue, Madison, WI 53705, USA
| | - Vincent L. Cryns
- Department of Medicine, University of Wisconsin Carbone Cancer Center, University of Wisconsin-Madison, School of Medicine and Public Health; 1111 Highland Avenue, Madison, WI 53705, USA,These authors contributed equally to this work,Correspondence: (R.A.A.); (V.L.C.)
| | - Richard A. Anderson
- University of Wisconsin-Madison, School of Medicine and Public Health; 1300 University Avenue, Madison, WI 53706, USA,These authors contributed equally to this work,Correspondence: (R.A.A.); (V.L.C.)
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10
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Gupta S, Kumar M, Chaudhuri S, Kumar A. The non-canonical nuclear functions of key players of the PI3K-AKT-MTOR pathway. J Cell Physiol 2022; 237:3181-3204. [PMID: 35616326 DOI: 10.1002/jcp.30782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/05/2022] [Accepted: 05/02/2022] [Indexed: 12/29/2022]
Abstract
The PI3K-AKT-MTOR signal transduction pathway is one of the essential signalling cascades within the cell due to its involvement in many vital functions. The pathway initiates with the recruitment of phosphatidylinositol-3 kinases (PI3Ks) onto the plasma membrane, generating phosphatidylinositol-3,4,5-triphosphate [PtdIns(3,4,5)P3 ] and subsequently activating AKT. Being the central node of the PI3K network, AKT activates the mechanistic target of rapamycin kinase complex 1 (MTORC1) via Tuberous sclerosis complex 2 inhibition in the cytoplasm. Although the cytoplasmic role of the pathway has been widely explored for decades, we now know that most of the effector molecules of the PI3K axis diverge from the canonical route and translocate to other cell organelles including the nucleus. The presence of phosphoinositides (PtdIns) inside the nucleus itself indicates the existence of a nuclear PI3K signalling. The nuclear localization of these signaling components is evident in regulating many nuclear processes like DNA replication, transcription, DNA repair, maintenance of genomic integrity, chromatin architecture, and cell cycle control. Here, our review intends to present a comprehensive overview of the nuclear functions of the PI3K-AKT-MTOR signaling biomolecules.
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Affiliation(s)
- Sakshi Gupta
- Department of Molecular Reproduction, Development & Genetics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Mukund Kumar
- Department of Molecular Reproduction, Development & Genetics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Soumi Chaudhuri
- Department of Molecular Reproduction, Development & Genetics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Arun Kumar
- Department of Molecular Reproduction, Development & Genetics, Indian Institute of Science, Bangalore, Karnataka, India
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Marosi M, Nenov MN, Di Re J, Dvorak NM, Alshammari M, Laezza F. Inhibition of the Akt/PKB Kinase Increases Na v1.6-Mediated Currents and Neuronal Excitability in CA1 Hippocampal Pyramidal Neurons. Int J Mol Sci 2022; 23:ijms23031700. [PMID: 35163623 PMCID: PMC8836202 DOI: 10.3390/ijms23031700] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 01/21/2022] [Accepted: 01/28/2022] [Indexed: 02/07/2023] Open
Abstract
In neurons, changes in Akt activity have been detected in response to the stimulation of transmembrane receptors. However, the mechanisms that lead to changes in neuronal function upon Akt inhibition are still poorly understood. In the present study, we interrogate how Akt inhibition could affect the activity of the neuronal Nav channels with while impacting intrinsic excitability. To that end, we employed voltage-clamp electrophysiological recordings in heterologous cells expressing the Nav1.6 channel isoform and in hippocampal CA1 pyramidal neurons in the presence of triciribine, an inhibitor of Akt. We showed that in both systems, Akt inhibition resulted in a potentiation of peak transient Na+ current (INa) density. Akt inhibition correspondingly led to an increase in the action potential firing of the CA1 pyramidal neurons that was accompanied by a decrease in the action potential current threshold. Complementary confocal analysis in the CA1 pyramidal neurons showed that the inhibition of Akt is associated with the lengthening of Nav1.6 fluorescent intensity along the axonal initial segment (AIS), providing a mechanism for augmented neuronal excitability. Taken together, these findings provide evidence that Akt-mediated signal transduction might affect neuronal excitability in a Nav1.6-dependent manner.
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Affiliation(s)
- Mate Marosi
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX 77555, USA; (M.M.); (M.N.N.); (J.D.R.); (N.M.D.); (M.A.)
| | - Miroslav N. Nenov
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX 77555, USA; (M.M.); (M.N.N.); (J.D.R.); (N.M.D.); (M.A.)
| | - Jessica Di Re
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX 77555, USA; (M.M.); (M.N.N.); (J.D.R.); (N.M.D.); (M.A.)
| | - Nolan M. Dvorak
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX 77555, USA; (M.M.); (M.N.N.); (J.D.R.); (N.M.D.); (M.A.)
| | - Musaad Alshammari
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX 77555, USA; (M.M.); (M.N.N.); (J.D.R.); (N.M.D.); (M.A.)
- Department of Pharmacology, College of Pharmacy, King Saud University, Riyadh P.O. Box 145111, Saudi Arabia
| | - Fernanda Laezza
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX 77555, USA; (M.M.); (M.N.N.); (J.D.R.); (N.M.D.); (M.A.)
- Center for Addiction Research, Center for Biomedical Engineering and Mitchell, Center for Neurodegenerative Diseases, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
- Correspondence: ; Tel.: +1-(409)-772-9672; Fax: +1-(409)-772-9642
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12
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Lai ZY, Tsai KY, Chang SJ, Chuang YJ. Gain-of-Function Mutant TP53 R248Q Overexpressed in Epithelial Ovarian Carcinoma Alters AKT-Dependent Regulation of Intercellular Trafficking in Responses to EGFR/MDM2 Inhibitor. Int J Mol Sci 2021; 22:ijms22168784. [PMID: 34445495 PMCID: PMC8395913 DOI: 10.3390/ijms22168784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/07/2021] [Accepted: 08/12/2021] [Indexed: 01/27/2023] Open
Abstract
As the most common gene mutation found in cancers, p53 mutations are detected in up to 96% of high-grade serous ovarian carcinoma (HGSOC). Meanwhile, mutant p53 overexpression is known to drive oncogenic phenotypes in cancer patients and to sustain the activation of EGFR signaling. Previously, we have demonstrated that the combined inhibition of EGFR and MDM2-p53 pathways, by gefitinib and JNJ-26854165, exerts a strong synergistic lethal effect on HGSOC cells. In this study, we investigated whether the gain-of-function p53 mutation (p53R248Q) overexpression could affect EGFR-related signaling and the corresponding drug inhibition outcome in HGSOC. The targeted inhibition responses of gefitinib and JNJ-26854165, in p53R248Q-overexpressing cells, were extensively evaluated. We found that the phosphorylation of AKT increased when p53R248Q was transiently overexpressed. Immunocytochemistry analysis further showed that upon p53R248Q overexpression, several AKT-related regulatory proteins translocated in unique intracellular patterns. Subsequent analysis revealed that, under the combined inhibition of gefitinib and JNJ-26854165, the cytonuclear trafficking of EGFR and MDM2 was disrupted. Next, we analyzed the gefitinib and JNJ-26854165 responses and found differential sensitivity to the single- or combined-drug inhibitions in p53R248Q-overexpressing cells. Our findings suggested that the R248Q mutation of p53 in HGSOC caused significant changes in signaling protein function and trafficking, under EGFR/MDM2-targeted inhibition. Such knowledge could help to advance our understanding of the role of mutant p53 in ovarian carcinoma and to improve the prognosis of patients receiving EGFR/MDM2-targeted therapies.
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Affiliation(s)
- Zih-Yin Lai
- Department of Medical Science & Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 30013, Taiwan; (Z.-Y.L.); (K.-Y.T.)
| | - Kai-Yun Tsai
- Department of Medical Science & Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 30013, Taiwan; (Z.-Y.L.); (K.-Y.T.)
| | - Shing-Jyh Chang
- Department of Obstetrics and Gynecology, Hsinchu MacKay Memorial Hospital, Hsinchu 30071, Taiwan
- Correspondence: (S.-J.C.); (Y.-J.C.); Tel.: +886-3-6119595 (S.-J.C.); +886-3-5742764 (Y.-J.C.); Fax: +886-3-6110900 (S.-J.C.); +886-3-5715934 (Y.-J.C.)
| | - Yung-Jen Chuang
- Department of Medical Science & Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 30013, Taiwan; (Z.-Y.L.); (K.-Y.T.)
- Correspondence: (S.-J.C.); (Y.-J.C.); Tel.: +886-3-6119595 (S.-J.C.); +886-3-5742764 (Y.-J.C.); Fax: +886-3-6110900 (S.-J.C.); +886-3-5715934 (Y.-J.C.)
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13
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Anjali A, Fatima U, Manu MS, Ramasamy S, Senthil-Kumar M. Structure and regulation of SWEET transporters in plants: An update. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 156:1-6. [PMID: 32891967 DOI: 10.1016/j.plaphy.2020.08.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/16/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
Sugar will eventually be exported transporters (SWEETs), a novel family of sugar transporters found in both eukaryotes and prokaryotes, facilitate sugar flux across the cell membrane. Although these transporters were first discovered in plants, their homologs have been reported in different organisms. SWEETs have critical roles in various developmental processes, including phloem loading, nectar secretion, and pathogen nutrition. The structure of bacterial homologs, called SemiSWEETs, has been well studied thus far. Here, we provide an overview of SWEET protein structure and dynamic function by analyzing the solved crystal structures and predicted models that are available for a few SWEETs in a monocot plant (rice) and dicot plant (Arabidopsis thaliana). Despite the advancement in structure-related studies, the regulation of SWEETs remains unknown. In light of reported regulatory mechanisms of a few other sugar transporters, we propose the regulation of SWEETs at the post-translational level. We then enumerate the potential post-translational modification sites in SWEETs using computational tools. Overall, in this review, we critically analyze SWEET protein structure in plants to predict the post-translational regulation of SWEETs. Such findings have a direct bearing on plant nutrition and defense and targeting the regulation at these levels will be important in crop improvement.
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Affiliation(s)
- Anjali Anjali
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Urooj Fatima
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - M S Manu
- Biochemical Science Division, CSIR-National Chemical Laboratory, Pune, 411008, India
| | - Sureshkumar Ramasamy
- Biochemical Science Division, CSIR-National Chemical Laboratory, Pune, 411008, India
| | - Muthappa Senthil-Kumar
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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14
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Jiang N, Dai Q, Su X, Fu J, Feng X, Peng J. Role of PI3K/AKT pathway in cancer: the framework of malignant behavior. Mol Biol Rep 2020; 47:4587-4629. [PMID: 32333246 PMCID: PMC7295848 DOI: 10.1007/s11033-020-05435-1] [Citation(s) in RCA: 296] [Impact Index Per Article: 74.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/03/2020] [Indexed: 12/12/2022]
Abstract
Given that the PI3K/AKT pathway has manifested its compelling influence on multiple cellular process, we further review the roles of hyperactivation of PI3K/AKT pathway in various human cancers. We state the abnormalities of PI3K/AKT pathway in different cancers, which are closely related with tumorigenesis, proliferation, growth, apoptosis, invasion, metastasis, epithelial-mesenchymal transition, stem-like phenotype, immune microenvironment and drug resistance of cancer cells. In addition, we investigated the current clinical trials of inhibitors against PI3K/AKT pathway in cancers and found that the clinical efficacy of these inhibitors as monotherapy has so far been limited despite of the promising preclinical activity, which means combinations of targeted therapy may achieve better efficacies in cancers. In short, we hope to feature PI3K/AKT pathway in cancers to the clinic and bring the new promising to patients for targeted therapies.
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Affiliation(s)
- Ningni Jiang
- Department of Pathology, The Third Affiliated Hospital of Guangzhou Medical University, 63 Duobao Road, Guangzhou, 510150 China
- The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150 China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, 510150 China
| | - Qijie Dai
- Department of Pathology, The Third Affiliated Hospital of Guangzhou Medical University, 63 Duobao Road, Guangzhou, 510150 China
- The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150 China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, 510150 China
| | - Xiaorui Su
- Department of Pathology, The Third Affiliated Hospital of Guangzhou Medical University, 63 Duobao Road, Guangzhou, 510150 China
- The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150 China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, 510150 China
| | - Jianjiang Fu
- Department of Pathology, The Third Affiliated Hospital of Guangzhou Medical University, 63 Duobao Road, Guangzhou, 510150 China
- The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150 China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, 510150 China
| | - Xuancheng Feng
- Department of Pathology, The Third Affiliated Hospital of Guangzhou Medical University, 63 Duobao Road, Guangzhou, 510150 China
- The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150 China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, 510150 China
| | - Juan Peng
- Department of Pathology, The Third Affiliated Hospital of Guangzhou Medical University, 63 Duobao Road, Guangzhou, 510150 China
- The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150 China
- Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, 510150 China
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157 USA
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15
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Yudushkin I. Control of Akt activity and substrate phosphorylation in cells. IUBMB Life 2020; 72:1115-1125. [PMID: 32125765 PMCID: PMC7317883 DOI: 10.1002/iub.2264] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 02/22/2020] [Indexed: 12/20/2022]
Abstract
Protein kinase B/Akt is a serine/threonine kinase that links receptors coupled to the PI3K lipid kinase to cellular anabolic pathways. Its activity in cells is controlled by reversible phosphorylation and an intramolecular lipid-controlled allosteric switch. In this review, I outline the current progress in understanding Akt regulatory mechanisms, define three models of Akt activation in cells, and highlight how intramolecular allosterism cooperates with cell-autonomous mechanisms to control Akt localization and activity and direct it toward specific sets of substrates in cells.
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Affiliation(s)
- Ivan Yudushkin
- Department of Structural and Computational BiologyUniversity of ViennaViennaAustria
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16
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Gallyas Jr. F, Sumegi B. Mitochondrial Protection by PARP Inhibition. Int J Mol Sci 2020; 21:ijms21082767. [PMID: 32316192 PMCID: PMC7215481 DOI: 10.3390/ijms21082767] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/11/2020] [Accepted: 04/14/2020] [Indexed: 02/07/2023] Open
Abstract
Inhibitors of the nuclear DNA damage sensor and signalling enzyme poly(ADP-ribose) polymerase (PARP) have recently been introduced in the therapy of cancers deficient in double-strand DNA break repair systems, and ongoing clinical trials aim to extend their use from other forms of cancer non-responsive to conventional treatments. Additionally, PARP inhibitors were suggested to be repurposed for oxidative stress-associated non-oncological diseases resulting in a devastating outcome, or requiring acute treatment. Their well-documented mitochondria- and cytoprotective effects form the basis of PARP inhibitors’ therapeutic use for non-oncological diseases, yet can limit their efficacy in the treatment of cancers. A better understanding of the processes involved in their protective effects may improve the PARP inhibitors’ therapeutic potential in the non-oncological indications. To this end, we endeavoured to summarise the basic features regarding mitochondrial structure and function, review the major PARP activation-induced cellular processes leading to mitochondrial damage, and discuss the role of PARP inhibition-mediated mitochondrial protection in several oxidative stress-associated diseases.
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Affiliation(s)
- Ferenc Gallyas Jr.
- Department of Biochemistry and Medical Chemistry, University of Pecs Medical School, 7624 Pecs, Hungary;
- Szentagothai Research Centre, University of Pecs, 7624 Pecs, Hungary
- HAS-UP Nuclear-Mitochondrial Interactions Research Group, 1245 Budapest, Hungary
- Correspondence: ; Tel.: +36-72-536-278
| | - Balazs Sumegi
- Department of Biochemistry and Medical Chemistry, University of Pecs Medical School, 7624 Pecs, Hungary;
- Szentagothai Research Centre, University of Pecs, 7624 Pecs, Hungary
- HAS-UP Nuclear-Mitochondrial Interactions Research Group, 1245 Budapest, Hungary
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17
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Rashid MM, Shatabda S, Hasan MM, Kurata H. Recent Development of Machine Learning Methods in Microbial Phosphorylation Sites. Curr Genomics 2020; 21:194-203. [PMID: 33071613 PMCID: PMC7521030 DOI: 10.2174/1389202921666200427210833] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 04/12/2020] [Accepted: 04/13/2020] [Indexed: 01/10/2023] Open
Abstract
A variety of protein post-translational modifications has been identified that control many cellular functions. Phosphorylation studies in mycobacterial organisms have shown critical importance in diverse biological processes, such as intercellular communication and cell division. Recent technical advances in high-precision mass spectrometry have determined a large number of microbial phosphorylated proteins and phosphorylation sites throughout the proteome analysis. Identification of phosphorylated proteins with specific modified residues through experimentation is often labor-intensive, costly and time-consuming. All these limitations could be overcome through the application of machine learning (ML) approaches. However, only a limited number of computational phosphorylation site prediction tools have been developed so far. This work aims to present a complete survey of the existing ML-predictors for microbial phosphorylation. We cover a variety of important aspects for developing a successful predictor, including operating ML algorithms, feature selection methods, window size, and software utility. Initially, we review the currently available phosphorylation site databases of the microbiome, the state-of-the-art ML approaches, working principles, and their performances. Lastly, we discuss the limitations and future directions of the computational ML methods for the prediction of phosphorylation.
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Affiliation(s)
| | | | - Md. Mehedi Hasan
- Address correspondence to these authors at the Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan; Tel: +81-948-297-828;, E-mail: and Biomedical Informatics R&D Center, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan; Tel: +81-948-297-828; E-mail:
| | - Hiroyuki Kurata
- Address correspondence to these authors at the Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan; Tel: +81-948-297-828;, E-mail: and Biomedical Informatics R&D Center, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka, Fukuoka 820-8502, Japan; Tel: +81-948-297-828; E-mail:
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18
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Role of Akt Activation in PARP Inhibitor Resistance in Cancer. Cancers (Basel) 2020; 12:cancers12030532. [PMID: 32106627 PMCID: PMC7139751 DOI: 10.3390/cancers12030532] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 02/19/2020] [Accepted: 02/24/2020] [Indexed: 12/12/2022] Open
Abstract
Poly(ADP-ribose) polymerase (PARP) inhibitors have recently been introduced in the therapy of several types of cancers not responding to conventional treatments. However, de novo and acquired PARP inhibitor resistance is a significant limiting factor in the clinical therapy, and the underlying mechanisms are not fully understood. Activity of the cytoprotective phosphatidylinositol-3 kinase (PI3K)-Akt pathway is often increased in human cancer that could result from mutation, expressional change, or amplification of upstream growth-related factor signaling elements or elements of the Akt pathway itself. However, PARP-inhibitor-induced activation of the cytoprotective PI3K-Akt pathway is overlooked, although it likely contributes to the development of PARP inhibitor resistance. Here, we briefly summarize the biological role of the PI3K-Akt pathway. Next, we overview the significance of the PARP-Akt interplay in shock, inflammation, cardiac and cerebral reperfusion, and cancer. We also discuss a recently discovered molecular mechanism that explains how PARP inhibition induces Akt activation and may account for apoptosis resistance and mitochondrial protection in oxidative stress and in cancer.
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19
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Effects of phosphorylated estrogen receptor alpha on apoptosis in human endometrial epithelial cells. Anat Sci Int 2019; 95:240-250. [PMID: 31823335 DOI: 10.1007/s12565-019-00515-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 11/29/2019] [Indexed: 01/15/2023]
Abstract
It is known that the activities of estrogen receptor α (ERα) can be modulated by epidermal growth factor (EGF) through the phosphatidylinostitol 3-kinase-alpha serine/threonine protein kinase (PI3K-AKT) pathway by phosphorylation. To clarify how ERα functions are regulated in endometrial cells during menstrual cycle, molecules related to phosphorylation of ERα (pERα) were examined. It was found that the expression of phosphorylated AKT on serine 473 (pAKT-Ser473) was increased during the proliferative phase, but decreased in the secretory phase. Although the expression of pAKT on threonine 308 in the proliferative phase was only identified in the wall of arterioles, it was strongly expressed in the cytoplasm of endometrial glandular cells after entering the secretory phase. Further observations revealed that while the expression of pERα-Ser104 was constant, pERα-Ser118 was expressed following a cyclic pattern similar to that of the pAKT-Ser473. Following treatment with specific inhibitors for EGFR-PI3K-AKT pathway, it was found that while the expression of pERα-Ser118 and pERα-Ser167 was inhibited, the induced apoptosis could be antagonized by the addition of estrogen, indicating that a mitochondrial pathway is involved. Therefore, pAKT and pERα or ERα could act cooperatively on coiled arterioles and endometrial cells in order to control menstrual cycle.
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20
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Kearney AL, Cooke KC, Norris DM, Zadoorian A, Krycer JR, Fazakerley DJ, Burchfield JG, James DE. Serine 474 phosphorylation is essential for maximal Akt2 kinase activity in adipocytes. J Biol Chem 2019; 294:16729-16739. [PMID: 31548312 DOI: 10.1074/jbc.ra119.010036] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/15/2019] [Indexed: 01/06/2023] Open
Abstract
The Ser/Thr protein kinase Akt regulates essential biological processes such as cell survival, growth, and metabolism. Upon growth factor stimulation, Akt is phosphorylated at Ser474; however, how this phosphorylation contributes to Akt activation remains controversial. Previous studies, which induced loss of Ser474 phosphorylation by ablating its upstream kinase mTORC2, have implicated Ser474 phosphorylation as a driver of Akt substrate specificity. Here we directly studied the role of Akt2 Ser474 phosphorylation in 3T3-L1 adipocytes by preventing Ser474 phosphorylation without perturbing mTORC2 activity. This was achieved by utilizing a chemical genetics approach, where ectopically expressed S474A Akt2 was engineered with a W80A mutation to confer resistance to the Akt inhibitor MK2206, and thus allow its activation independent of endogenous Akt. We found that insulin-stimulated phosphorylation of four bona fide Akt substrates (TSC2, PRAS40, FOXO1/3a, and AS160) was reduced by ∼50% in the absence of Ser474 phosphorylation. Accordingly, insulin-stimulated mTORC1 activation, protein synthesis, FOXO nuclear exclusion, GLUT4 translocation, and glucose uptake were attenuated upon loss of Ser474 phosphorylation. We propose a model where Ser474 phosphorylation is required for maximal Akt2 kinase activity in adipocytes.
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Affiliation(s)
- Alison L Kearney
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Kristen C Cooke
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Dougall M Norris
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Armella Zadoorian
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - James R Krycer
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Daniel J Fazakerley
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - James G Burchfield
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - David E James
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia .,Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
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21
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Yu Y, Xiong Y, Ladeiras D, Yang Z, Ming XF. Myosin 1b Regulates Nuclear AKT Activation by Preventing Localization of PTEN in the Nucleus. iScience 2019; 19:39-53. [PMID: 31349190 PMCID: PMC6660601 DOI: 10.1016/j.isci.2019.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 05/17/2019] [Accepted: 07/05/2019] [Indexed: 02/08/2023] Open
Abstract
Insulin-induced AKT activation is dependent on phosphoinositide 3-kinase and opposed by tumor suppressor phosphatase and tensin homolog (PTEN). Our previous study demonstrates that myosin 1b (MYO1B) mediates arginase-II-induced activation of mechanistic target of rapamycin complex 1 that is regulated by AKT. However, the role of MYO1B in AKT activation is unknown. Here we show that silencing MYO1B in mouse embryonic fibroblasts (MEF) inhibits insulin-induced nuclear but not cytoplasmic AKT activation accompanied by elevated nuclear PTEN level. Co-immunoprecipitation, co-immunostaining, and proximity ligation assay show an interaction of MYO1B and PTEN resulting in reduced nuclear PTEN. Moreover, the elevated nuclear PTEN upon silencing MYO1B promotes apoptosis of MEFs and melanoma B16F10 cells. Taken together, we demonstrate that MYO1B, by interacting with PTEN, prevents nuclear localization of PTEN contributing to nuclear AKT activation and suppression of cell apoptosis. This may present a therapeutic approach for cancer treatment such as melanoma. MYO1B, by interacting with PTEN, prevents PTEN localization in the nucleus MYO1B prevents nuclear localization of PTEN depending on its motor activity This contributes to nuclear AKT activation and suppression of cell apoptosis Targeting MYO1B may represent a therapeutic approach for cancer treatment
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Affiliation(s)
- Yi Yu
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland
| | - Yuyan Xiong
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland
| | - Diogo Ladeiras
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland
| | - Zhihong Yang
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland.
| | - Xiu-Fen Ming
- Cardiovascular and Aging Research, Department of Endocrinology, Metabolism and Cardiovascular System, Medicine Section, Faculty of Science and Medicine, University of Fribourg, Chemin du Musée 5, 1700 Fribourg, Switzerland.
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22
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Revathidevi S, Munirajan AK. Akt in cancer: Mediator and more. Semin Cancer Biol 2019; 59:80-91. [PMID: 31173856 DOI: 10.1016/j.semcancer.2019.06.002] [Citation(s) in RCA: 348] [Impact Index Per Article: 69.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 04/29/2019] [Accepted: 06/03/2019] [Indexed: 02/06/2023]
Abstract
Akt is a serine/threonine kinase and it participates in the key role of the PI3K signaling pathway. The Akt can be activated by a wide range of growth signals and the biochemical mechanisms leading to Akt activation are well defined. Once activated, Akt modulates the function of many downstream proteins involved in cellular survival, proliferation, migration, metabolism, and angiogenesis. The Akt is a central node of many signaling pathways and it is frequently deregulated in many types of human cancers. In this review, we provide an overview of Akt function and its role in the hallmarks of human cancer. We also discussed various mechanisms of Akt dysregulation in cancers, including epigenetic modifications like methylation, post-transcriptional non-coding RNAs-mediated regulation, and the overexpression and mutation.
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Affiliation(s)
- Sundaramoorthy Revathidevi
- Department of Genetics, Dr. ALM PG Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, 113, Tamil Nadu, India
| | - Arasambattu Kannan Munirajan
- Department of Genetics, Dr. ALM PG Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, 113, Tamil Nadu, India.
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23
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Aftab S, Shakoori AR. Low glucose availability alters the expression of genes involved in initial adhesion of human glioblastoma cancer cell line SF767. J Cell Biochem 2019; 120:16824-16839. [PMID: 31111555 DOI: 10.1002/jcb.28940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 02/26/2019] [Accepted: 02/28/2019] [Indexed: 01/09/2023]
Abstract
Studying the metabolic pathways of cancer cells is considered as a key to control cancer malignancies and open windows for effective drug discovery against cancer. Of all the properties of a tumor, metastasis potential is a defining characteristic. Metastasis is controlled by a variety of factors that directly control the expression of cell adhesion proteins. In this study we have investigated the expression of cell to cell and cell to matrix adhesion protein genes during the initial phases of attachment of human glioblastoma cancer cell line SF767 (66Y old human female: UCSF Neurosurgery Tissue Bank) to the attachment surface under (Cell culture treated polystyrene plate bottom) glucose-rich and glucose-starved conditions. The aim was to imitate the natural microenvironment of glucose availability to cancer cells inside a tumor that triggers epithelial to mesenchymal transition (EMT). In this study, we have observed the gene expression of epithelial and mesenchymal isoforms of cadherin (E-CAD and N-CAD) and Ig like cell adhesion molecules (E-CAM and N-CAM) along with Integrin family subunits for the initial attachment of cancer cells. We observed that high glucose environments promoted cell survival and cell adhesion, whereas low glucose accelerated EMT by downregulating the expression level of integrin, E-CAD, and N-CAD, and upregulation of N-CAM during early period of cell adhesion. Low glucose availability also downregulated variety of structural and regulatory genes, such as zinc finger E-box binding home box 1A), cytokeratin, Snail, and β catenin, and upregulation of hypoxia-inducible factor 1, matrix metalloprotease 13/Collagenase 3, vimentim, p120, and fructose 1,6 bisphosphatase. Glucose conditions are more efficient for cancer studies in this case glioblastoma cells.
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Affiliation(s)
- Saira Aftab
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore, Pakistan
| | - Abdul Rauf Shakoori
- School of Biological Sciences, University of the Punjab, Quaid-i-Azam Campus, Lahore, Pakistan.,Department of Biochemistry, Faculty of Life Sciences, University of Central Punjab, Lahore, Pakistan
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24
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Sugiyama MG, Fairn GD, Antonescu CN. Akt-ing Up Just About Everywhere: Compartment-Specific Akt Activation and Function in Receptor Tyrosine Kinase Signaling. Front Cell Dev Biol 2019; 7:70. [PMID: 31131274 PMCID: PMC6509475 DOI: 10.3389/fcell.2019.00070] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/09/2019] [Indexed: 12/12/2022] Open
Abstract
The serine/threonine kinase Akt is a master regulator of many diverse cellular functions, including survival, growth, metabolism, migration, and differentiation. Receptor tyrosine kinases are critical regulators of Akt, as a result of activation of phosphatidylinositol-3-kinase (PI3K) signaling leading to Akt activation upon receptor stimulation. The signaling axis formed by receptor tyrosine kinases, PI3K and Akt, as well as the vast range of downstream substrates is thus central to control of cell physiology in many different contexts and tissues. This axis must be tightly regulated, as disruption of PI3K-Akt signaling underlies the pathology of many diseases such as cancer and diabetes. This sophisticated regulation of PI3K-Akt signaling is due in part to the spatial and temporal compartmentalization of Akt activation and function, including in specific nanoscale domains of the plasma membrane as well as in specific intracellular membrane compartments. Here, we review the evidence for localized activation of PI3K-Akt signaling by receptor tyrosine kinases in various specific cellular compartments, as well as that of compartment-specific functions of Akt leading to control of several fundamental cellular processes. This spatial and temporal control of Akt activation and function occurs by a large number of parallel molecular mechanisms that are central to regulation of cell physiology.
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Affiliation(s)
- Michael G Sugiyama
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Gregory D Fairn
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada.,Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Costin N Antonescu
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
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25
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AKT/protein kinase B associates with β-actin in the nucleus of melanoma cells. Biosci Rep 2019; 39:BSR20181312. [PMID: 30643008 PMCID: PMC6356016 DOI: 10.1042/bsr20181312] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/21/2018] [Accepted: 01/07/2019] [Indexed: 12/19/2022] Open
Abstract
The serine-threonine kinase AKT/PKB is a critical regulator of various essential cellular processes, and dysregulation of AKT has been implicated in many diseases, including cancer. Despite AKT action is known to function mainly in the cytoplasm, AKT has been reported to translocate to the nucleus. However, very little is known about the mechanism required for the nuclear import of AKT as well as its function in this cellular compartment. In the present study, we characterized the presence of endogenous nuclear AKT in human melanoma cells and addressed the possible role of AKT by exploring its potential association with key interaction nuclear partners. Confocal and Western blot analyses showed that both phosphorylated and non-phosphorylated forms of AKT are present in melanoma cells nuclei. Using mass spectrometry in combination with protein-crosslinking and co-immunoprecipitation, we identified a series of putative protein partners of nuclear AKT, including heterogeneous nuclear ribonucleoprotein (hnRNP), cytoskeleton proteins β-actin, γ-actin, β-actin-like 2 and vimentin. Confocal microscopy and biochemical analyses validated β-actin as a new nuclear AKT-interacting partner. Cofilin and active RNA Polymerase II, two proteins that have been described to interact and work in concert with nuclear actin in transcription regulation, were also found associated with nuclear AKT. Overall, the present study uncovered a yet unrecognized nuclear coupling of AKT and provides insights into the involvement of AKT in the interaction network of nuclear actin.
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26
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Carcinoma-associated fibroblasts affect sensitivity to oxaliplatin and 5FU in colorectal cancer cells. Oncotarget 2018; 7:59766-59780. [PMID: 27517495 PMCID: PMC5312347 DOI: 10.18632/oncotarget.11121] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/19/2016] [Indexed: 01/08/2023] Open
Abstract
The importance of tumor microenvironment (TME) as a relevant contributor to cancer progression and its role in the development of de novo resistance to targeted therapies has become increasingly apparent. However, the mechanisms of microenvironment-mediated drug resistance for nonspecific conventional chemotherapeutic agents, such as platinum compounds or antimetabolites, are still unclear. Here we describe a mechanism induced by soluble factors released by carcinoma-associated fibroblasts (CAFs) that induce the translocation of AKT, Survivin and P38 to the nucleus of tumor cells. These changes are guided to ensure DNA repair and the correct entrance and exit from mitosis in the presence of chemotherapy. We used conditioned media (CM) from normal-colonic fibroblasts and paired CAFs to assess dose response curves of oxaliplatin and 5-fluorouracil, separately or combined, compared with standard culture medium. We also evaluated a colony-forming assay and cell death to demonstrate the protective role of CAF-CM. Immunofluorescence confirmed the translocation of AKT, P38 and Survivin to the nucleus induced by CAF-soluble factors. We also have shown that STAT3 or P38 inhibition provides a promising strategy for overcoming microenvironment-mediated resistance. Conversely, pharmacologic AKT inhibition induces an antagonistic effect that relieves a cMET and STAT3-mediated compensatory feedback that might explain the failure of AKT inhibitors in the clinic so far.
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27
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Ebner M, Lučić I, Leonard TA, Yudushkin I. PI(3,4,5)P 3 Engagement Restricts Akt Activity to Cellular Membranes. Mol Cell 2017; 65:416-431.e6. [PMID: 28157504 DOI: 10.1016/j.molcel.2016.12.028] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 10/19/2016] [Accepted: 12/29/2016] [Indexed: 01/13/2023]
Abstract
Protein kinase B/Akt regulates cellular metabolism, survival, and proliferation in response to hormones and growth factors. Hyperactivation of Akt is frequently observed in cancer, while Akt inactivation is associated with severe diabetes. Here, we investigated the molecular and cellular mechanisms that maintain Akt activity proportional to the activating stimulus. We show that binding of phosphatidylinositol-3,4,5-trisphosphate (PIP3) or PI(3,4)P2 to the PH domain allosterically activates Akt by promoting high-affinity substrate binding. Conversely, dissociation from PIP3 was rate limiting for Akt dephosphorylation, dependent on the presence of the PH domain. In cells, active Akt associated primarily with cellular membranes. In contrast, a transforming mutation that uncouples kinase activation from PIP3 resulted in the accumulation of hyperphosphorylated, active Akt in the cytosol. Our results suggest that intramolecular allosteric and cellular mechanisms cooperate to restrict Akt activity to cellular membranes, thereby enhancing the fidelity of Akt signaling and the specificity of downstream substrate phosphorylation.
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Affiliation(s)
- Michael Ebner
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, Vienna Biocenter (VBC), Campus Vienna Biocenter 5, 1030 Vienna, Austria
| | - Iva Lučić
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, Vienna Biocenter (VBC), Campus Vienna Biocenter 5, 1030 Vienna, Austria
| | - Thomas A Leonard
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, Vienna Biocenter (VBC), Campus Vienna Biocenter 5, 1030 Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
| | - Ivan Yudushkin
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, Vienna Biocenter (VBC), Campus Vienna Biocenter 5, 1030 Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
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28
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Elucidating the role of the FoxO3a transcription factor in the IGF-1-induced migration and invasion of uveal melanoma cancer cells. Biomed Pharmacother 2016; 84:1538-1550. [DOI: 10.1016/j.biopha.2016.11.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/27/2016] [Accepted: 11/08/2016] [Indexed: 01/20/2023] Open
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29
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Akizuki R, Shimobaba S, Matsunaga T, Endo S, Ikari A. Claudin-5, -7, and -18 suppress proliferation mediated by inhibition of phosphorylation of Akt in human lung squamous cell carcinoma. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:293-302. [PMID: 27884700 DOI: 10.1016/j.bbamcr.2016.11.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/26/2016] [Accepted: 11/18/2016] [Indexed: 12/11/2022]
Abstract
Abnormal expression of claudin (CLDN) subtypes has been reported in various solid cancers. However, it is unknown which subtype plays a key role in the regulation of proliferation in cancer cells. The expression of CLDN3-5, 7, and 18 in human lung squamous carcinoma tissues was lower than that in normal tissue. Here, we examined which combination of exogenous CLDNs expression inhibits proliferation and the molecular mechanism using human lung squamous RERF-LC-AI cells. Real-time polymerase chain reaction and western blotting showed that CLDN3-5, 7, and 18 are little expressed in RERF-LC-AI cells. In the exogenously transfected cells, CLDN5, 7, and 18 were distributed in the cell-cell contact areas concomitant with ZO-1, a tight junctional scaffolding protein, whereas CLDN3 and 4 were not. Cell proliferation was individually and additively suppressed by CLDN5, 7, and 18. The expression of these CLDNs showed no cytotoxicity compared with mock cells. CLDN5, 7, and 18 increased p21 and decreased cyclin D1, resulting in the suppression of cell cycle G1-S transition. The expression of these CLDNs inhibited phosphorylation of Akt without affecting phosphorylated ERK1/2. Furthermore, these CLDNs inhibited the nuclear localization of Akt and its association with 3-phosphoinositide-dependent protein kinase-1 (PDK1). The suppression of G1-S transition caused by CLDN5, 7, and 18 was rescued by the expression of constitutively active-Akt. We suggest that the reduction of CLDN5, 7, and 18 expression loses the suppressive ability of interaction between PDK1 and Akt and causes sustained phosphorylation of Akt, resulting in the disordered proliferation in lung squamous carcinoma cells.
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Affiliation(s)
- Risa Akizuki
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University
| | - Shun Shimobaba
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University
| | - Toshiyuki Matsunaga
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University
| | - Satoshi Endo
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University
| | - Akira Ikari
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University.
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30
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CD38 Deficiency Protects the Heart from Ischemia/Reperfusion Injury through Activating SIRT1/FOXOs-Mediated Antioxidative Stress Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:7410257. [PMID: 27547294 PMCID: PMC4983367 DOI: 10.1155/2016/7410257] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 05/25/2016] [Accepted: 06/14/2016] [Indexed: 01/05/2023]
Abstract
Ischemia/reperfusion (I/R) injury induces irreversible oxidative stress damage to the cardiac muscle. We previously observed that CD38 deficiency remarkably protects mouse embryonic fibroblasts (MEFs) from oxidative stress-induced injury. However, whether CD38 deficiency protects from I/R injury in the heart is not explored. Here, we showed that the hearts of CD38 deficient mice or wild type mice supplied with exogenous NAD were significantly protected from ischemia/reperfusion injury, seen as reduction of the myocardial infarct sizes when the mice were subjected to 30 min ischemia followed by 24 hours of reperfusion. Consistently, the protection of CD38 deficiency on hypoxia/reoxygenation (H/R) injury was confirmed with a CD38 knockdown H9c2 stable cell line. Furthermore, we observed that knockdown of CD38 remarkably inhibited ROS generation and intracellular Ca2+ overloading induced by H/R in H9c2 cells. The FOXO1 and FOXO3 expressions were significantly elevated by H/R injury in CD38 knockdown cells compared with normal H9c2 cells. The cell immunofluorescence assay showed that FOXO1 nuclear translocation was significantly increased in CD38 knockdown H9c2 cells. In addition, we demonstrated that the increase of FOXO1 nuclear translocation was associated with the increased expressions of antioxidant catalase and SOD2 and the attenuated expression of the ROS generation enzyme NOX4. In conclusion, our results provide new evidence that CD38 deficiency protects the heart from I/R injury through activating SIRT1/FOXOs-mediated antioxidative stress pathway.
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31
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PI3K/AKT Signaling Regulates H3K4 Methylation in Breast Cancer. Cell Rep 2016; 15:2692-704. [PMID: 27292631 DOI: 10.1016/j.celrep.2016.05.046] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 02/25/2016] [Accepted: 05/10/2016] [Indexed: 12/15/2022] Open
Abstract
Post-translational histone H3 modifications regulate transcriptional competence. The mechanisms by which the epigenome is regulated in response to oncogenic signaling remain unclear. Here we show that H3K4me3 is increased in breast tumors driven by an activated PIK3CA allele and that inhibition of PI3K/AKT signaling reduces promoter-associated H3K4me3 in human breast cancer cells. We show that the H3K4 demethylase KDM5A is an AKT target and that phosphorylation of KDM5A regulates its nuclear localization and promoter occupancy. Supporting a role for KDM5A in mediating PI3K/AKT transcriptional effects, the decreased expression in response to AKT inhibition of a subset of cell-cycle genes associated with poor clinical outcome is blunted by KDM5A silencing. Our data identify a mechanism by which PI3K/AKT signaling modulates the cancer epigenome through controlling H3K4 methylation and suggest that KDM5A subcellular localization and genome occupancy may be pharmacodynamic markers of the activity of PI3K/AKT inhibitors currently in clinical development.
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32
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Chen J, Lian X, Du J, Xu S, Wei J, Pang L, Song C, He L, Wang S. Inhibition of phosphorylated Ser473-Akt from translocating into the nucleus contributes to 2-cell arrest and defective zygotic genome activation in mouse preimplantation embryogenesis. Dev Growth Differ 2016; 58:280-92. [DOI: 10.1111/dgd.12273] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 02/03/2016] [Accepted: 02/05/2016] [Indexed: 12/01/2022]
Affiliation(s)
- Junming Chen
- Department of Human Anatomy, Histology and Embryology; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
| | - Xiuli Lian
- Department of Human Anatomy, Histology and Embryology; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
| | - Juan Du
- Department of Human Anatomy, Histology and Embryology; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
| | - Songhua Xu
- Department of Human Anatomy, Histology and Embryology; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
| | - Jianen Wei
- Department of Human Anatomy, Histology and Embryology; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
| | - Lili Pang
- Cellular and Developmental Engineering Center; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
| | - Chanchan Song
- Cellular and Developmental Engineering Center; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
| | - Lin He
- Department of Human Anatomy, Histology and Embryology; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
| | - Shie Wang
- Department of Human Anatomy, Histology and Embryology; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
- Cellular and Developmental Engineering Center; School of Basic Medical Sciences; Fujian Medical University; Fuzhou Fujian 350108 China
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33
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Delisle A, Ferraris E, Plante I. Chronic exposure to hexachlorobenzene results in down-regulation of connexin43 in the breast. ENVIRONMENTAL RESEARCH 2015; 143:229-240. [PMID: 26519829 DOI: 10.1016/j.envres.2015.10.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/29/2015] [Accepted: 10/19/2015] [Indexed: 06/05/2023]
Abstract
Decreased expression of connexins has been associated with cancer, but the underlying mechanisms are poorly understood. We have previously shown that a 5 day exposure to hexachlorobenzene (HCB) resulted in decreased connexins expression in hepatocytes 45 days later, and that this down-regulation was linked to activation of Akt through the ILK pathway. Because HCB promotes cancer in both the liver and breast, the present study aimed to determine if the mechanisms are similar in both tissues. MCF-12A breast cells were thus transfected with vectors coding for either Akt or a constitutively active form of Akt. In those cells, activation of Akt was correlated with decreased Cx43 levels. Female rats were then exposed to HCB by gavage either following the same protocol used previously for the liver or through a chronic exposure. While no changes were observed after the 5 days exposure protocol, chronic exposure to HCB resulted in increased Akt levels and decreased Cx43 levels in breast cells. In vitro, Akt was activated in MCF-12A cells exposed to HCB either for 7 days or chronically, but no changes were observed in junctional proteins. Together, these results suggested that, while activation of Akt can decrease Cx43 expression in breast cells in vitro, other mechanisms are involved during HCB exposure, leading to a decrease in Cx43 levels in a model- and duration-dependent manner. Finally, we showed that HCB effects are tissue specific, as we did not observe the same results in breast and liver tissues.
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Affiliation(s)
- Ariane Delisle
- INRS-Institut Armand-Frappier, Laval, Québec, Canada H7V 1B7
| | | | - Isabelle Plante
- INRS-Institut Armand-Frappier, Laval, Québec, Canada H7V 1B7. http://www.inrs.ca
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34
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Li F, Qu H, Cao HC, Li MH, Chen C, Chen XF, Yu B, Yu L, Zheng LM, Zhang W. Both FOXO3a and FOXO1 are involved in the HGF-protective pathway against apoptosis in endothelial cells. Cell Biol Int 2015; 39:1131-7. [PMID: 25952685 DOI: 10.1002/cbin.10486] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/29/2015] [Indexed: 12/11/2022]
Affiliation(s)
- Fang Li
- Biomedical Research Institute; Shenzhen Peking University-the Hong Kong University of Science and Technology Medical Center; Shenzhen Guangdong China
| | - Huan Qu
- Department of Cardiovascularology; Peking University Shenzhen Hospital; Shenzhen Guangdong China
| | - Heng-Chang Cao
- Department of Emergency Surgery; Peking University Shenzhen Hospital; Shenzhen Guangdong China
| | - Mei-Hong Li
- Department of Cardiovascularology; Peking University Shenzhen Hospital; Shenzhen Guangdong China
| | - Chen Chen
- Department of Cardiovascularology; Peking University Shenzhen Hospital; Shenzhen Guangdong China
| | - Xiao-Fan Chen
- Biomedical Research Institute; Shenzhen Peking University-the Hong Kong University of Science and Technology Medical Center; Shenzhen Guangdong China
| | - Bo Yu
- Department of Dermatology; Peking University Shenzhen Hospital; Shenzhen Guangdong China
| | - Lin Yu
- Department of obstetrics and gynaecology; Peking University Shenzhen Hospital; Shenzhen Guangdong China
| | - Le-Min Zheng
- Department of Cardiovascular Sciences; Peking University Health Science Center; Peking University; Peking China
| | - Wei Zhang
- Biomedical Research Institute; Shenzhen Peking University-the Hong Kong University of Science and Technology Medical Center; Shenzhen Guangdong China
- Department of Dermatology; Peking University Shenzhen Hospital; Shenzhen Guangdong China
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35
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Davis WJ, Lehmann PZ, Li W. Nuclear PI3K signaling in cell growth and tumorigenesis. Front Cell Dev Biol 2015; 3:24. [PMID: 25918701 PMCID: PMC4394695 DOI: 10.3389/fcell.2015.00024] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Accepted: 03/27/2015] [Indexed: 12/12/2022] Open
Abstract
The PI3K/Akt signaling pathway is a major driving force in a variety of cellular functions. Dysregulation of this pathway has been implicated in many human diseases including cancer. While the activity of the cytoplasmic PI3K/Akt pathway has been extensively studied, the functions of these molecules and their effector proteins within the nucleus are poorly understood. Harboring key cellular processes such as DNA replication and repair as well as nascent messenger RNA transcription, the nucleus provides a unique compartmental environment for protein–protein and protein–DNA/RNA interactions required for cell survival, growth, and proliferation. Here we summarize recent advances made toward elucidating the nuclear PI3K/Akt signaling cascade and its key components within the nucleus as they pertain to cell growth and tumorigenesis. This review covers the spatial and temporal localization of the major nuclear kinases having PI3K activities and the counteracting phosphatases as well as the role of nuclear PI3K/Akt signaling in mRNA processing and exportation, DNA replication and repair, ribosome biogenesis, cell survival, and tumorigenesis.
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Affiliation(s)
- William J Davis
- College of Medical Sciences, Washington State University Spokane, WA, USA
| | - Peter Z Lehmann
- College of Medical Sciences, Washington State University Spokane, WA, USA
| | - Weimin Li
- College of Medical Sciences, Washington State University Spokane, WA, USA
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36
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Merkely B, Gara E, Lendvai Z, Skopál J, Leja T, Zhou W, Kosztin A, Várady G, Mioulane M, Bagyura Z, Németh T, Harding SE, Földes G. Signaling via PI3K/FOXO1A pathway modulates formation and survival of human embryonic stem cell-derived endothelial cells. Stem Cells Dev 2015; 24:869-78. [PMID: 25387407 PMCID: PMC4367527 DOI: 10.1089/scd.2014.0247] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Vascular derivatives of human embryonic stem cells (hESC) are being developed as sources of tissue-specific cells for organ regeneration. However, identity of developmental pathways that modulate the specification of endothelial cells is not known yet. We studied phosphatidylinositol 3-kinase (PI3K)-Forkhead box O transcription factor 1A (FOXO1A) pathways during differentiation of hESC toward endothelial lineage and on proliferation, maturation, and cell death of hESC-derived endothelial cells (hESC-EC). During differentiation of hESC, expression of FOXO1A transcription factor was linked to the expression of a cluster of angiogenesis- and vascular remodeling-related genes. PI3K inhibitor LY294002 activated FOXO1A and induced formation of CD31(+) hESC-EC. In contrast, differentiating hESC with silenced FOXO1A by small interfering RNA (siRNA) showed lower mRNA levels of CD31 and angiopoietin2. LY294002 decreased proliferative activity of purified hESC-EC, while FOXO1A siRNA increased their proliferation. LY294002 inhibits migration and tube formation of hESC-EC; in contrast, FOXO1A siRNA increased in vitro tube formation activity of hESC-EC. After in vivo conditioning of cells in athymic nude rats, cells retain their low FOXO1A expression levels. PI3K/FOXO1A pathway is important for function and survival of hESC-EC and in the regulation of endothelial cell fate. Understanding these properties of hESC-EC may help in future applications for treatment of injured organs.
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Affiliation(s)
- Béla Merkely
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Edit Gara
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | | | - Judit Skopál
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Thomas Leja
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Wenhua Zhou
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | | | - György Várady
- Membrane Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Maxime Mioulane
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Zsolt Bagyura
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Tamás Németh
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Sian E. Harding
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Gábor Földes
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary.,National Heart and Lung Institute, Imperial College London, London, United Kingdom
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37
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Vasou O, Skagias L, Anastasia M, Paulina A, Patsouris E, Politi E. Detection of pAkt protein in imprint cytology of invasive breast cancer: Correlation with HER2/neu, hormone receptors, and other clinicopathological variables. Cytojournal 2015; 12:6. [PMID: 25838835 PMCID: PMC4382762 DOI: 10.4103/1742-6413.153965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 01/14/2015] [Indexed: 11/16/2022] Open
Abstract
Purpose: Akt is a serine/threonine protein kinase and has emerged as a crucial regulator of widely divergent cellular processes, including apoptosis, proliferation, differentiation, and metabolism. Activation of Akt/protein kinase B has been positively associated with human epidermal growth-factor receptor 2 (HER2)/neu overexpression in breast carcinoma and a worse outcome among endocrine treated patients. The Akt signaling pathway currently attracts considerable attention as a new target for effective therapeutic strategies. We therefore investigated the relationship between activation of Akt and clinicopathologic variables including hormone receptor and HER2/neu status. Methods: Archival tumor tissues from 100 patients with invasive breast carcinoma were analyzed by immunocytochemistry. This study describes the results of immunocytochemical pAkt expression in breast carcinoma imprints, prepared from cut surfaces of freshly removed tumors. Both nuclear and cytoplasmic expressions were evaluated for pAkt. Results: Nuclear and cytoplasmic positive scores of 72% (72/100) and 42% (42/100), respectively, were found. Coexistence of nuclear and cytoplasmic staining was observed in 32 cases (32/100). Nuclear positive staining correlated with HER2/neu overexpression (P = 0.043) and was significantly associated with positive involvement of axillary lymph nodes (P = 0.013). No correlation was found between cytoplasmic pAkt rate and clinicopathological parameters, estrogen receptor, progesterone receptor or HER2/neu expression. Conclusions: pAkt expression can be evaluated in cytological material and may add valuable information to current prognostic models for breast cancer. pAkt overexpression appears to be linked with potentially aggressive tumor phenotype in invasive breast carcinoma.
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Affiliation(s)
- Olympia Vasou
- Address: Department of Cytopathology, Aretaieion University Hospital, Athens, Greece, Europe
| | - Lazaros Skagias
- Department of Cytopathology, 424 General Army Hospital, Thessaloniki, Greece, Europe
| | - Margariti Anastasia
- Department of Pathology, Mitera General Hospital and Maternity Clinic, Athens, Greece, Europe
| | - Athanasiadou Paulina
- Department of Pathology, Medical School, University of Athens, Athens, Greece, Europe
| | - Efstratios Patsouris
- Department of Pathology, Medical School, University of Athens, Athens, Greece, Europe
| | - Ekaterini Politi
- Address: Department of Cytopathology, Aretaieion University Hospital, Athens, Greece, Europe
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Recurrent BCAM-AKT2 fusion gene leads to a constitutively activated AKT2 fusion kinase in high-grade serous ovarian carcinoma. Proc Natl Acad Sci U S A 2015; 112:E1272-7. [PMID: 25733895 DOI: 10.1073/pnas.1501735112] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
High-grade serous ovarian cancer (HGSC) is among the most lethal forms of cancer in women. Excessive genomic rearrangements, which are expected to create fusion oncogenes, are the hallmark of this cancer. Here we report a cancer-specific gene fusion between BCAM, a membrane adhesion molecule, and AKT2, a key kinase in the PI3K signaling pathway. This fusion is present in 7% of the 60 patient cancers tested, a significant frequency considering the highly heterogeneous nature of this malignancy. Further, we provide direct evidence that BCAM-AKT2 is translated into an in-frame fusion protein in the patient's tumor. The resulting AKT2 fusion kinase is membrane-associated, constitutively phosphorylated, and activated as a functional kinase in cells. Unlike endogenous AKT2, whose activity is tightly regulated by external stimuli, BCAM-AKT2 escapes the regulation from external stimuli. Moreover, a BCAM-AKT2 fusion gene generated via chromosomal translocation using the CRISPR/Cas9 system leads to focus formation in both OVCAR8 and HEK-293T cell lines, suggesting that BCAM-AKT2 is oncogenic. Together, the results indicate that BCAM-AKT2 expression is a new mechanism of AKT2 kinase activation in HGSC. BCAM-AKT2 is the only fusion gene in HGSC that is proven to translate an aberrant yet functional kinase fusion protein with oncogenic properties. This recurrent genomic alteration is a potential therapeutic target and marker of a clinically relevant subtype for tailored therapy of HGSC.
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Xu K, Li F, Ma L, Wang B, Zhang H, Ni M, Hong F, Shen W, Li B. Mechanism of enhanced Bombyx mori nucleopolyhedrovirus-resistance by titanium dioxide nanoparticles in silkworm. PLoS One 2015; 10:e0118222. [PMID: 25692869 PMCID: PMC4333570 DOI: 10.1371/journal.pone.0118222] [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: 09/23/2014] [Accepted: 01/11/2015] [Indexed: 02/07/2023] Open
Abstract
The infection of Bombyx mori nucleopolyhedrovirus (BmNPV) in silkworms is often lethal. It is difficult to prevent, and its lethality is correlated with both viral particle characteristics and silkworm strains. Low doses of titanium dioxide nanoparticles (TiO2 NPs) can promote silkworm growth and improve its resistance to organophosphate pesticides. In this study, TiO2 NPs' effect on BmNPV resistance was investigated by analyzing the characteristics of BmNPV proliferation and transcriptional differences in silkworm midgut and the transcriptional changes of immunity related genes after feeding with TiO2 NPs. We found that low doses of TiO2 NPs improved the resistance of silkworm against BmNPV by 14.88-fold, with the mortalities of the experimental group and control group being 0.56% and 8.33% at 144 h, respectively. The proliferation of BmNPV in the midgut was significantly increased 72 h after infection in both experimental and control groups; the control group reached the peak at 120 h, while the experimental group took 24 more hours to reach the maximal value that was 12.63 times lower than the control, indicating that TiO2 NPs can inhibit BmNPV proliferation in the midgut. Consistently, the expression of the BmNPV-resistant gene Bmlipase-1 had the same increase pattern as the proliferation changes. Immune signaling pathway analysis revealed that TiO2 NPs inhibited the proliferation of silkworm BmNPV to reduce the activation levels of janus kinase/signal transducer and activator of transcription (JAK/STAT) and phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway, while promoting the expression of Bmakt to improve the immunity. Overall, our results demonstrate that TiO2 NPs increase silkworm resistance against BmNPV by inhibiting virus proliferation and improving immunity in silkworms.
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Affiliation(s)
- Kaizun Xu
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Fanchi Li
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Lie Ma
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Binbin Wang
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Hua Zhang
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Min Ni
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Fashui Hong
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Weide Shen
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
- National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Bing Li
- School of Basic Medicine and Biological Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
- National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, Jiangsu 215123, P.R. China
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40
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Hu B, Emdad L, Bacolod MD, Kegelman TP, Shen XN, Alzubi MA, Das SK, Sarkar D, Fisher PB. Astrocyte elevated gene-1 interacts with Akt isoform 2 to control glioma growth, survival, and pathogenesis. Cancer Res 2014; 74:7321-32. [PMID: 25304263 DOI: 10.1158/0008-5472.can-13-2978] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The oncogene astrocyte elevated gene-1 (AEG-1; MTDH) is highly expressed in glioblastoma multiforme (GBM) and many other types of cancer, where it activates multiple signaling pathways that drive proliferation, invasion, angiogenesis, chemoresistance, radioresistance, and metastasis. AEG-1 activates the Akt signaling pathway and Akt and c-Myc are positive regulators of AEG-1 transcription, generating a positive feedback loop between AEG-1 and Akt in regulating tumorigenesis. Here, we describe in GBM cells a direct interaction between an internal domain of AEG-1 and the PH domain of Akt2, a major driver in GBM. Expression and interaction of AEG-1 and Akt2 are elevated in GBM and contribute to tumor cell survival, proliferation, and invasion. Clinically, in silico gene expression and immunohistochemical analyses of patient specimens showed that AEG-1 and Akt2 expression correlated with GBM progression and reduced patient survival. AEG-1-Akt2 interaction prolonged stabilization of Akt2 phosphorylation at S474, regulating downstream signaling cascades that enable cell proliferation and survival. Disrupting AEG-1-Akt2 interaction by competitive binding of the Akt2-PH domain led to reduced cell viability and invasion. When combined with AEG-1 silencing, conditional expression of Akt2-PH markedly increased survival in an orthotopic mouse model of human GBM. Our study uncovers a novel molecular mechanism by which AEG-1 augments glioma progression and offers a rationale to block AEG-1-Akt2 signaling function as a novel GBM treatment.
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Affiliation(s)
- Bin Hu
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Luni Emdad
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia. VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia. VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Manny D Bacolod
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia. VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Timothy P Kegelman
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Xue-Ning Shen
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Mohammad A Alzubi
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Swadesh K Das
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia. VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Devanand Sarkar
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia. VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia. VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, Virginia. VCU Institute of Molecular Medicine, Virginia Commonwealth University, School of Medicine, Richmond, Virginia. VCU Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, Virginia.
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Ahn JY. Neuroprotection signaling of nuclear akt in neuronal cells. Exp Neurobiol 2014; 23:200-6. [PMID: 25258566 PMCID: PMC4174610 DOI: 10.5607/en.2014.23.3.200] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 08/11/2014] [Accepted: 08/12/2014] [Indexed: 12/29/2022] Open
Abstract
Akt is one of the central kinases that perform a pivotal function in mediating survival signaling in a wide range of neuronal cell types in response to growth factor stimulation. The recent findings of a number of targets for Akt suggest that it prohibits neuronal death by both impinging on the cytoplasmic cell death machinery and by regulating nuclear proteins. The presence of active Akt in the nuclei of mammalian cells is no longer debatable, and this has been corroborated by the finding of multiple targets in the nucleus of PC12 cells. However, it is also clear that the nuclear Akt signaling exists independent of the cytosolic Akt signaling, thereby showing a distinctive feature of nuclear Akt signaling as opposed to its cytosolic counterpart. The principal objective of this review is to summarize our current state of knowledge regarding nuclear Akt signaling in neuronal survival, and to introduce current theories regarding the roles of nuclear Akt in neuron.
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Affiliation(s)
- Jee-Yin Ahn
- Department of Molecular Cell Biology, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea
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42
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Girardi C, James P, Zanin S, Pinna LA, Ruzzene M. Differential phosphorylation of Akt1 and Akt2 by protein kinase CK2 may account for isoform specific functions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1865-74. [DOI: 10.1016/j.bbamcr.2014.04.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 03/25/2014] [Accepted: 04/17/2014] [Indexed: 10/25/2022]
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43
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Yang XF, He Y, Li HY, Liu X, Chen H, Liu JB, Ji WJ, Wang B, Chen LN. Hepatoprotective effects of erythropoietin on D-galactosamine/lipopolysaccharide-induced fulminant hepatic failure in mice. Mol Med Rep 2014; 10:555-9. [PMID: 24788561 DOI: 10.3892/mmr.2014.2164] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 03/24/2014] [Indexed: 01/18/2023] Open
Abstract
Fulminant hepatic failure is a severe clinical syndrome associated with a high rate of patient mortality. Recent studies have shown that in addition to its hematopoietic effect, erythropoietin (EPO) has multiple protective effects and exhibits antiapoptotic, antioxidant and anti-inflammatory activities. The present study aimed to determine the hepatoprotective effect of EPO and to elucidate the underlying mechanisms using a D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced model of acute liver injury. Experimental groups of mice were administered with various doses of EPO (1,000, 3,000 or 10,000 U/kg, intraperitoneal) once per day for 3 days, prior to injection with D-GalN (700 mg/kg)/LPS (10 µg/kg). Mice were sacrificed 8 h after treatment with D‑GalN/LPS. Liver function and histopathology, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH‑Px) activities and EPO receptor (EPOR) and phosphatidylinositol 3-kinase (PI3K) mRNA expression were evaluated. D-GalN/LPS administration markedly induced liver injury, as evidenced by elevated levels of serum aminotransferases, as well as histopathological changes. Compared with the D-GalN/LPS group, pretreatment with EPO significantly decreased the levels of aspartate aminotransferase, alanine aminotransferase and MDA, and increased the activities of SOD and GSH-Px. Furthermore, the protective effects of EPO were paralleled by an upregulation in the mRNA expression of EPOR and PI3K. These data suggest that EPO can ameliorate D-GalN/LPS-induced acute liver injury by reducing oxidative stress and upregulating the mRNA expression of EPOR and PI3K.
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Affiliation(s)
- Xue-Fei Yang
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yi He
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Hai-Yuan Li
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Xin Liu
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Huan Chen
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Jian-Bang Liu
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Wen-Jun Ji
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Bing Wang
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Li-Na Chen
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
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Koushik AB, Welter BH, Rock ML, Temesvari LA. A genomewide overexpression screen identifies genes involved in the phosphatidylinositol 3-kinase pathway in the human protozoan parasite Entamoeba histolytica. EUKARYOTIC CELL 2014; 13:401-11. [PMID: 24442890 PMCID: PMC3957588 DOI: 10.1128/ec.00329-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 01/12/2014] [Indexed: 11/20/2022]
Abstract
Entamoeba histolytica is a protozoan parasite that causes amoebic dysentery and liver abscess. E. histolytica relies on motility, phagocytosis, host cell adhesion, and proteolysis of extracellular matrix for virulence. In eukaryotic cells, these processes are mediated in part by phosphatidylinositol 3-kinase (PI3K) signaling. Thus, PI3K may be critical for virulence. We utilized a functional genomics approach to identify genes whose products may operate in the PI3K pathway in E. histolytica. We treated a population of trophozoites that were overexpressing genes from a cDNA library with a near-lethal dose of the PI3K inhibitor wortmannin. This screen was based on the rationale that survivors would be overexpressing gene products that directly or indirectly function in the PI3K pathway. We sequenced the overexpressed genes in survivors and identified a cDNA encoding a Rap GTPase, a protein previously shown to participate in the PI3K pathway. This supports the validity of our approach. Genes encoding a coactosin-like protein, EhCoactosin, and a serine-rich E. histolytica protein (SREHP) were also identified. Cells overexpressing EhCoactosin or SREHP were also less sensitive to a second PI3K inhibitor, LY294002. This corroborates the link between these proteins and PI3K. Finally, a mutant cell line with an increased level of phosphatidylinositol (3,4,5)-triphosphate, the product of PI3K activity, exhibited increased expression of SREHP and EhCoactosin. This further supports the functional connection between these proteins and PI3K in E. histolytica. To our knowledge, this is the first forward-genetics screen adapted to reveal genes participating in a signal transduction pathway in this pathogen.
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Affiliation(s)
- Amrita B. Koushik
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, USA
- Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, South Carolina, USA
| | - Brenda H. Welter
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
- Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, South Carolina, USA
| | - Michelle L. Rock
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
- Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, South Carolina, USA
| | - Lesly A. Temesvari
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
- Eukaryotic Pathogens Innovation Center (EPIC), Clemson University, Clemson, South Carolina, USA
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Lai TW, Zhang S, Wang YT. Excitotoxicity and stroke: identifying novel targets for neuroprotection. Prog Neurobiol 2013; 115:157-88. [PMID: 24361499 DOI: 10.1016/j.pneurobio.2013.11.006] [Citation(s) in RCA: 734] [Impact Index Per Article: 66.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/28/2013] [Accepted: 11/29/2013] [Indexed: 01/22/2023]
Abstract
Excitotoxicity, the specific type of neurotoxicity mediated by glutamate, may be the missing link between ischemia and neuronal death, and intervening the mechanistic steps that lead to excitotoxicity can prevent stroke damage. Interest in excitotoxicity began fifty years ago when monosodium glutamate was found to be neurotoxic. Evidence soon demonstrated that glutamate is not only the primary excitatory neurotransmitter in the adult brain, but also a critical transmitter for signaling neurons to degenerate following stroke. The finding led to a number of clinical trials that tested inhibitors of excitotoxicity in stroke patients. Glutamate exerts its function in large by activating the calcium-permeable ionotropic NMDA receptor (NMDAR), and different subpopulations of the NMDAR may generate different functional outputs, depending on the signaling proteins directly bound or indirectly coupled to its large cytoplasmic tail. Synaptic activity activates the GluN2A subunit-containing NMDAR, leading to activation of the pro-survival signaling proteins Akt, ERK, and CREB. During a brief episode of ischemia, the extracellular glutamate concentration rises abruptly, and stimulation of the GluN2B-containing NMDAR in the extrasynaptic sites triggers excitotoxic neuronal death via PTEN, cdk5, and DAPK1, which are directly bound to the NMDAR, nNOS, which is indirectly coupled to the NMDAR via PSD95, and calpain, p25, STEP, p38, JNK, and SREBP1, which are further downstream. This review aims to provide a comprehensive summary of the literature on excitotoxicity and our perspectives on how the new generation of excitotoxicity inhibitors may succeed despite the failure of the previous generation of drugs.
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Affiliation(s)
- Ted Weita Lai
- Graduate Institute of Clinical Medical Science, China Medical University, 91 Hsueh-Shih Road, 40402 Taichung, Taiwan; Translational Medicine Research Center, China Medical University Hospital, 2 Yu-De Road, 40447 Taichung, Taiwan.
| | - Shu Zhang
- Translational Medicine Research Center, China Medical University Hospital, 2 Yu-De Road, 40447 Taichung, Taiwan; Brain Research Center, University of British Columbia, 2211 Wesbrook Mall, V6T 2B5 Vancouver, Canada
| | - Yu Tian Wang
- Brain Research Center, University of British Columbia, 2211 Wesbrook Mall, V6T 2B5 Vancouver, Canada.
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Mejía-García TA, Portugal CC, Encarnação TG, Prado MAM, Paes-de-Carvalho R. Nitric oxide regulates AKT phosphorylation and nuclear translocation in cultured retinal cells. Cell Signal 2013; 25:2424-39. [DOI: 10.1016/j.cellsig.2013.08.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 08/07/2013] [Accepted: 08/10/2013] [Indexed: 02/07/2023]
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47
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Yip PY, Cooper WA, Kohonen-Corish MRJ, Lin BPC, McCaughan BC, Boyer MJ, Kench JG, Horvath LG. Phosphorylated Akt expression is a prognostic marker in early-stage non-small cell lung cancer. J Clin Pathol 2013; 67:333-40. [PMID: 24265323 DOI: 10.1136/jclinpath-2013-201870] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
AIMS To determine the prognostic significance of pAkt expression in order to identify high-risk stage IB patients with non-small cell lung cancer (NSCLC) in an exploratory study. METHODS We identified 471 consecutive patients with stage IB primary NSCLC according to the American Joint Commission on Cancer 6th edition tumour-node-metastasis (TNM) staging system, who underwent surgical resection between 1990 and 2008. Patients who received neoadjuvant or adjuvant treatments were excluded. Pathology reports were reviewed, and pathological characteristics were extracted. Expression of phosphorylated Akt (pAkt) in both cytoplasmic and nuclear locations was assessed by immunohistochemistry, and clinicopathological factors were analysed against 10-year overall survival using Kaplan-Meier and Cox proportional hazards model. RESULTS 455 (96.6%) cancers were adequate for pAkt immunohistochemical analysis. The prevalence of pAkt expression in the cytoplasm and nucleus of the cancers was 60.7% and 43.7%, respectively. Patients whose cancers expressed higher levels of cytoplasmic pAkt had a trend towards longer overall survival than those with lower levels (p=0.06). Conversely, patients whose cancers expressed higher levels of nuclear pAkt had a poorer prognosis than those with lower levels of expression (p=0.02). Combined low cytoplasmic/high nuclear expression of pAkt was an independent predictor of overall survival (HR=2.86 (95% CI 1.35 to 6.04); p=0.006) when modelled with age (HR=1.05 (95% CI 1.03 to 1.07); p<0.001), extent of operation (HR=2.11 (95% CI 1.48 to 3.01); p<0.001), visceral pleural invasion (HR=1.63 (95% CI 1.24 to 2.15); p<0.001), gender, tumour size, histopathological type and grade (p>0.05). CONCLUSIONS Level of expression of pAkt in the cytoplasm and nucleus is an independent prognostic factor that may help to select patients with high-risk disease.
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Affiliation(s)
- P Y Yip
- Department of Medical Oncology, Sydney Cancer Centre, Royal Prince Alfred Hospital, , Sydney, New South Wales, Australia
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Sin1 phosphorylation impairs mTORC2 complex integrity and inhibits downstream Akt signalling to suppress tumorigenesis. Nat Cell Biol 2013; 15:1340-50. [PMID: 24161930 PMCID: PMC3827117 DOI: 10.1038/ncb2860] [Citation(s) in RCA: 201] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Accepted: 09/18/2013] [Indexed: 12/15/2022]
Abstract
The mechanistic target of rapamycin (mTOR) functions as a critical regulator of cellular growth and metabolism by forming multi-component, yet functionally distinct complexes mTORC1 and mTORC2. Although mTORC2 has been implicated in mTORC1 activation, little is known about how mTORC2 is regulated. Here we report that phosphorylation of Sin1 at Thr 86 and Thr 398 suppresses mTORC2 kinase activity by dissociating Sin1 from mTORC2. Importantly, Sin1 phosphorylation, triggered by S6K or Akt, in a cellular context-dependent manner, inhibits not only insulin- or IGF-1-mediated, but also PDGF- or EGF-induced Akt phosphorylation by mTORC2, demonstrating a negative regulation of mTORC2 independent of IRS-1 and Grb10. Finally, a cancer-patient-derived Sin1-R81T mutation impairs Sin1 phosphorylation, leading to hyper-activation of mTORC2 by bypassing this negative regulation. Together, our results reveal a Sin1-phosphorylation-dependent mTORC2 regulation, providing a potential molecular mechanism by which mutations in the mTORC1-S6K-Sin1 signalling axis might cause aberrant hyper-activation of the mTORC2-Akt pathway, which facilitates tumorigenesis.
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49
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Nin DS, Ali AB, Okumura K, Asou N, Chen CS, Chng WJ, Khan M. Akt-induced phosphorylation of N-CoR at serine 1450 contributes to its misfolded conformational dependent loss (MCDL) in acute myeloid leukemia of the M5 subtype. PLoS One 2013; 8:e70891. [PMID: 23940660 PMCID: PMC3733915 DOI: 10.1371/journal.pone.0070891] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 06/25/2013] [Indexed: 11/18/2022] Open
Abstract
The nuclear receptor co-repressor (N-CoR) is a key component of the generic co-repressor complex that plays an important role in the control of cellular growth and differentiation. As shown by us recently, the growth suppressive function of N-CoR largely relies on its capacity to repress Flt3, a key regulator of cellular gorwth during normal and malignant hematopoesis. We further demonstrated how de-repression of Flt3 due to the misfolded conformation dependent loss (MCDL) of N-CoR contributed to malignant growth in acute myeloid leukemia (AML). However, the molecular mechanism underlying the MCDL of N-CoR and its implication in AML pathogenesis is not fully understood. Here, we report that Akt-induced phosphorylation of N-CoR at the consensus Akt motif is crucial for its misfolding and subsequent loss in AML (AML-M5). N-CoR displayed significantly higher level of serine specific phosphorylation in almost all AML-M5 derived cells and was subjected to processing by AML-M5 specific aberrant protease activity. To identify the kinase linked to N-CoR phosphorylation, a library of activated kinases was screened with the extracts of AML cells; leading to the identification of Akt as the putative kinase linked to N-CoR phosphorylation. Consistent with this finding, a constitutively active Akt consistently phosphorylated N-CoR leading to its misfolding; while the therapeutic and genetic ablation of Akt largely abrogated the MCDL of N-CoR in AML-M5 cells. Site directed mutagenic analysis of N-CoR identified serine 1450 as the crucial residue whose phosphorylation by Akt was essential for the misfolding and loss of N-CoR protein. Moreover, Akt-induced phosphorylation of N-CoR contributed to the de-repression of Flt3, suggesting a cross talk between Akt signaling and N-CoR misfolding pathway in the pathogenesis of AML-M5. The N-CoR misfolding pathway could be the common downstream thread of pleiotropic Akt signaling activated by various oncogenic insults in some subtypes of leukemia and solid tumors.
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Affiliation(s)
- Dawn Sijin Nin
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine,
National University of Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of
Medicine, National University of Singapore, Singapore
| | - Azhar Bin Ali
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
| | - Koichi Okumura
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
| | - Norio Asou
- Department of Haematology, Kumamoto University, Kumamoto, Japan
| | - Chien-Shing Chen
- Division of Hematologyand Oncology, School of Medicine, Loma Linda University, Loma Linda, California, United States of America
| | - Wee Joo Chng
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine,
National University of Singapore, Singapore
- Department of Haematology-Oncology, National Cancer
Institute of Singapore, National University Health System,
Singapore
| | - Matiullah Khan
- Cancer Science Institute of Singapore, Yong Loo Lin School
of Medicine, National University of Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine,
National University of Singapore, Singapore
- School of Medicine, Asian Institute of Medicine, Science and Technology (AIMST), Bedong, Malaysia
- * E-mail: ,
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Shimamura M, Zhou P, Casolla B, Qian L, Capone C, Kurinami H, Iadecola C, Anrather J. Prostaglandin E2 type 1 receptors contribute to neuronal apoptosis after transient forebrain ischemia. J Cereb Blood Flow Metab 2013; 33:1207-14. [PMID: 23632967 PMCID: PMC3734771 DOI: 10.1038/jcbfm.2013.69] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 04/02/2013] [Accepted: 04/03/2013] [Indexed: 11/09/2022]
Abstract
Cyclooxygenase-2-derived prostaglandin E2 (PGE2) contributes to excitotoxic and ischemic neuronal cell death by engaging neuronal PGE2 type 1 receptors (EP1R). Our previous studies have shown that EP1R signaling resulted in disturbances of intracellular Ca(2+) homeostasis and suppression of the pro-survival protein kinase AKT. The aim of this study was to investigate whether these pathophysiological mechanism have a role in the neuronal cell death after transient forebrain ischemia. Mice were subjected to ischemia/reperfusion by bilateral common carotid artery occlusion. Hippocampal cornu ammonis area 1 (CA1) neuronal cell death was determined 5 days after reperfusion. Animals treated with the EP1R antagonist SC51089 or EP1R-deficient mice (EP1(-/-)) showed significantly less neuronal injury as compared to vehicle-treated wild-type controls. Benefits of EP1R blockage were still evident 14 days after injury. Better neuronal survival was correlated with reduced neuronal caspase-3 activity and decreased nuclear translocation of the apoptosis-inducing factor . Neuroprotection could be reverted by intracerebroventricular administration of the phosphoinositide 3-kinase inhibitor LY294002 and was not further increased by the calcineurin inhibitor FK506. These data implicate EP1R in postischemic neuronal apoptosis possibly by facilitating AKT inhibition.
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Affiliation(s)
- Munehisa Shimamura
- Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
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