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Wang Y, Vandewalle N, De Veirman K, Vanderkerken K, Menu E, De Bruyne E. Targeting mTOR signaling pathways in multiple myeloma: biology and implication for therapy. Cell Commun Signal 2024; 22:320. [PMID: 38862983 PMCID: PMC11165851 DOI: 10.1186/s12964-024-01699-3] [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: 02/13/2024] [Accepted: 06/03/2024] [Indexed: 06/13/2024] Open
Abstract
Multiple Myeloma (MM), a cancer of terminally differentiated plasma cells, is the second most prevalent hematological malignancy and is incurable due to the inevitable development of drug resistance. Intense protein synthesis is a distinctive trait of MM cells, supporting the massive production of clonal immunoglobulins or free light chains. The mammalian target of rapamycin (mTOR) kinase is appreciated as a master regulator of vital cellular processes, including regulation of metabolism and protein synthesis, and can be found in two multiprotein complexes, mTORC1 and mTORC2. Dysregulation of these complexes is implicated in several types of cancer, including MM. Since mTOR has been shown to be aberrantly activated in a large portion of MM patients and to play a role in stimulating MM cell survival and resistance to several existing therapies, understanding the regulation and functions of the mTOR complexes is vital for the development of more effective therapeutic strategies. This review provides a general overview of the mTOR pathway, discussing key discoveries and recent insights related to the structure and regulation of mTOR complexes. Additionally, we highlight findings on the mechanisms by which mTOR is involved in protein synthesis and delve into mTOR-mediated processes occurring in MM. Finally, we summarize the progress and current challenges of drugs targeting mTOR complexes in MM.
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Affiliation(s)
- Yanmeng Wang
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
| | - Niels Vandewalle
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
| | - Kim De Veirman
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Universitair Ziekenhuis Brussel (UZ Brussel), Jette, Belgium
| | - Karin Vanderkerken
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium
| | - Eline Menu
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium.
| | - Elke De Bruyne
- Translational Oncology Research Center (TORC) - Team Hematology and Immunology (HEIM), Vrije Universiteit Brussel (VUB), Jette, Belgium.
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2
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Jhanwar-Uniyal M, Zeller SL, Spirollari E, Das M, Hanft SJ, Gandhi CD. Discrete Mechanistic Target of Rapamycin Signaling Pathways, Stem Cells, and Therapeutic Targets. Cells 2024; 13:409. [PMID: 38474373 DOI: 10.3390/cells13050409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/14/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a serine/threonine kinase that functions via its discrete binding partners to form two multiprotein complexes, mTOR complex 1 and 2 (mTORC1 and mTORC2). Rapamycin-sensitive mTORC1, which regulates protein synthesis and cell growth, is tightly controlled by PI3K/Akt and is nutrient-/growth factor-sensitive. In the brain, mTORC1 is also sensitive to neurotransmitter signaling. mTORC2, which is modulated by growth factor signaling, is associated with ribosomes and is insensitive to rapamycin. mTOR regulates stem cell and cancer stem cell characteristics. Aberrant Akt/mTOR activation is involved in multistep tumorigenesis in a variety of cancers, thereby suggesting that the inhibition of mTOR may have therapeutic potential. Rapamycin and its analogues, known as rapalogues, suppress mTOR activity through an allosteric mechanism that only suppresses mTORC1, albeit incompletely. ATP-catalytic binding site inhibitors are designed to inhibit both complexes. This review describes the regulation of mTOR and the targeting of its complexes in the treatment of cancers, such as glioblastoma, and their stem cells.
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Affiliation(s)
- Meena Jhanwar-Uniyal
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Sabrina L Zeller
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Eris Spirollari
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Mohan Das
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Simon J Hanft
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
| | - Chirag D Gandhi
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY 10595, USA
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3
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Ragupathi A, Kim C, Jacinto E. The mTORC2 signaling network: targets and cross-talks. Biochem J 2024; 481:45-91. [PMID: 38270460 PMCID: PMC10903481 DOI: 10.1042/bcj20220325] [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: 10/02/2023] [Revised: 11/29/2023] [Accepted: 12/18/2023] [Indexed: 01/26/2024]
Abstract
The mechanistic target of rapamycin, mTOR, controls cell metabolism in response to growth signals and stress stimuli. The cellular functions of mTOR are mediated by two distinct protein complexes, mTOR complex 1 (mTORC1) and mTORC2. Rapamycin and its analogs are currently used in the clinic to treat a variety of diseases and have been instrumental in delineating the functions of its direct target, mTORC1. Despite the lack of a specific mTORC2 inhibitor, genetic studies that disrupt mTORC2 expression unravel the functions of this more elusive mTOR complex. Like mTORC1 which responds to growth signals, mTORC2 is also activated by anabolic signals but is additionally triggered by stress. mTORC2 mediates signals from growth factor receptors and G-protein coupled receptors. How stress conditions such as nutrient limitation modulate mTORC2 activation to allow metabolic reprogramming and ensure cell survival remains poorly understood. A variety of downstream effectors of mTORC2 have been identified but the most well-characterized mTORC2 substrates include Akt, PKC, and SGK, which are members of the AGC protein kinase family. Here, we review how mTORC2 is regulated by cellular stimuli including how compartmentalization and modulation of complex components affect mTORC2 signaling. We elaborate on how phosphorylation of its substrates, particularly the AGC kinases, mediates its diverse functions in growth, proliferation, survival, and differentiation. We discuss other signaling and metabolic components that cross-talk with mTORC2 and the cellular output of these signals. Lastly, we consider how to more effectively target the mTORC2 pathway to treat diseases that have deregulated mTOR signaling.
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Affiliation(s)
- Aparna Ragupathi
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, U.S.A
| | - Christian Kim
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, U.S.A
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, U.S.A
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4
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Liu Y, Zhang M, Jang H, Nussinov R. The allosteric mechanism of mTOR activation can inform bitopic inhibitor optimization. Chem Sci 2024; 15:1003-1017. [PMID: 38239681 PMCID: PMC10793652 DOI: 10.1039/d3sc04690g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024] Open
Abstract
mTOR serine/threonine kinase is a cornerstone in the PI3K/AKT/mTOR pathway. Yet, the detailed mechanism of activation of its catalytic core is still unresolved, likely due to mTOR complexes' complexity. Its dysregulation was implicated in cancer and neurodevelopmental disorders. Using extensive molecular dynamics (MD) simulations and compiled published experimental data, we determine exactly how mTOR's inherent motifs can control the conformational changes in the kinase domain, thus kinase activity. We also chronicle the critical regulation by the unstructured negative regulator domain (NRD). When positioned inside the catalytic cleft (NRD IN state), mTOR tends to adopt a deep and closed catalytic cleft. This is primarily due to the direct interaction with the FKBP-rapamycin binding (FRB) domain which restricts it, preventing substrate access. Conversely, when outside the catalytic cleft (NRD OUT state), mTOR favors an open conformation, exposing the substrate-binding site on the FRB domain. We further show how an oncogenic mutation (L2427R) promotes shifting the mTOR ensemble toward the catalysis-favored state. Collectively, we extend mTOR's "active-site restriction" mechanism and clarify mutation action. In particular, our mechanism suggests that RMC-5552 (RMC-6272) bitopic inhibitors may benefit from adjustment of the (PEG8) linker length when targeting certain mTOR variants. In the cryo-EM mTOR/RMC-5552 structure, the distance between the allosteric and orthosteric inhibitors is ∼22.7 Å. With a closed catalytic cleft, this linker bridges the sites. However, in our activation mechanism, in the open cleft it expands to ∼24.7 Å, offering what we believe to be the first direct example of how discovering an activation mechanism can potentially increase the affinity of inhibitors targeting mutants.
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Affiliation(s)
- Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA +1-301-846-5579
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA +1-301-846-5579
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA +1-301-846-5579
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University Tel Aviv 69978 Israel
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5
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Khalil MI, Ali MM, Holail J, Houssein M. Growth or death? Control of cell destiny by mTOR and autophagy pathways. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 185:39-55. [PMID: 37944568 DOI: 10.1016/j.pbiomolbio.2023.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/08/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023]
Abstract
One of the central regulators of cell growth, proliferation, and metabolism is the mammalian target of rapamycin, mTOR, which exists in two structurally and functionally different complexes: mTORC1 and mTORC2; unlike m TORC2, mTORC1 is activated in response to the sufficiency of nutrients and is inhibited by rapamycin. mTOR complexes have critical roles not only in protein synthesis, gene transcription regulation, proliferation, tumor metabolism, but also in the regulation of the programmed cell death mechanisms such as autophagy and apoptosis. Autophagy is a conserved catabolic mechanism in which damaged molecules are recycled in response to nutrient starvation. Emerging evidence indicates that the mTOR signaling pathway is frequently activated in tumors. In addition, dysregulation of autophagy was associated with the development of a variety of human diseases, such as cancer and aging. Since mTOR can inhibit the induction of the autophagic process from the early stages of autophagosome formation to the late stage of lysosome degradation, the use of mTOR inhibitors to regulate autophagy could be considered a potential therapeutic option. The present review sheds light on the mTOR and autophagy signaling pathways and the mechanisms of regulation of mTOR-autophagy.
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Affiliation(s)
- Mahmoud I Khalil
- Department of Biological Sciences, Faculty of Science, Beirut Arab University, Beirut, 11072809, Lebanon; Molecular Biology Unit, Department of Zoology, Faculty of Science, Alexandria University, Alexandria, 21511, Egypt.
| | - Mohamad M Ali
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, SE-751 23, Uppsala, Sweden.
| | - Jasmine Holail
- Department of Biochemistry and Molecular Medicine, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia; Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom.
| | - Marwa Houssein
- Department of Biological Sciences, Faculty of Science, Beirut Arab University, Beirut, 11072809, Lebanon.
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6
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Frappaolo A, Giansanti MG. Using Drosophila melanogaster to Dissect the Roles of the mTOR Signaling Pathway in Cell Growth. Cells 2023; 12:2622. [PMID: 37998357 PMCID: PMC10670727 DOI: 10.3390/cells12222622] [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: 10/23/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/25/2023] Open
Abstract
The evolutionarily conserved target of rapamycin (TOR) serine/threonine kinase controls eukaryotic cell growth, metabolism and survival by integrating signals from the nutritional status and growth factors. TOR is the catalytic subunit of two distinct functional multiprotein complexes termed mTORC1 (mechanistic target of rapamycin complex 1) and mTORC2, which phosphorylate a different set of substrates and display different physiological functions. Dysregulation of TOR signaling has been involved in the development and progression of several disease states including cancer and diabetes. Here, we highlight how genetic and biochemical studies in the model system Drosophila melanogaster have been crucial to identify the mTORC1 and mTORC2 signaling components and to dissect their function in cellular growth, in strict coordination with insulin signaling. In addition, we review new findings that involve Drosophila Golgi phosphoprotein 3 in regulating organ growth via Rheb-mediated activation of mTORC1 in line with an emerging role for the Golgi as a major hub for mTORC1 signaling.
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Affiliation(s)
- Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
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7
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Chen Y, Jiao D, He H, Sun H, Liu Y, Shi Q, Zhang P, Li Y, Mo R, Gao K, Wang C. Disruption of the Keap1-mTORC2 axis by cancer-derived Keap1/mLST8 mutations leads to oncogenic mTORC2-AKT activation. Redox Biol 2023; 67:102872. [PMID: 37688978 PMCID: PMC10498434 DOI: 10.1016/j.redox.2023.102872] [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: 06/09/2023] [Revised: 08/29/2023] [Accepted: 09/01/2023] [Indexed: 09/11/2023] Open
Abstract
The mechanistic target of the rapamycin (mTOR) pathway, which participates in the regulation of cellular growth and metabolism, is aberrantly regulated in various cancer types. The mTOR complex 2 (mTORC2), which consists of the core components mTOR, Rictor, mSin1, and mLST8, primarily responds to growth signals. However, the coordination between mTORC2 assembly and activity remains poorly understood. Keap1, a major sensor of oxidative stress in cells, functions as a substrate adaptor for Cullin 3-RING E3 ubiquitin ligase (CRL3) to promote proteasomal degradation of NF-E2-related factor 2 (NRF2), which is a transcription factor that protects cells against oxidative and electrophilic stress. In the present study, we demonstrate that Keap1 binds to mLST8 via a conserved ETGE motif. The CRL3Keap1 ubiquitin ligase complex promotes non-degradative ubiquitination of mLST8, thus reducing mTORC2 complex integrity and mTORC2-AKT activation. However, this effect can be prevented by oxidative/electrophilic stresses and growth factor signaling-induced reactive oxygen species (ROS) burst. Cancer-derived Keap1 or mLST8 mutations disrupt the Keap1-mLST8 interaction and allow mLST8 to evade Keap1-mediated ubiquitination, thereby enhancing mTORC2-AKT activation and promoting cell malignancy and remodeling cell metabolism. Our findings provide new insights into the molecular mechanisms of Keap1/mLST8 mutation-driven tumorigenesis by promoting mTORC2-AKT activation, which is independent of the canonical NRF2 pathway.
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Affiliation(s)
- Yingji Chen
- Shanghai Stomatological Hospital & School of Stomatology, State Key Lab of Genetic Engineering, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan University, Shanghai, 200438, PR China
| | - Dongyue Jiao
- Shanghai Stomatological Hospital & School of Stomatology, State Key Lab of Genetic Engineering, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan University, Shanghai, 200438, PR China
| | - Huiying He
- Shanghai Stomatological Hospital & School of Stomatology, State Key Lab of Genetic Engineering, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan University, Shanghai, 200438, PR China
| | - Huiru Sun
- Shanghai Stomatological Hospital & School of Stomatology, State Key Lab of Genetic Engineering, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan University, Shanghai, 200438, PR China
| | - Yajuan Liu
- Shanghai Stomatological Hospital & School of Stomatology, State Key Lab of Genetic Engineering, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan University, Shanghai, 200438, PR China
| | - Qing Shi
- Shanghai Stomatological Hospital & School of Stomatology, State Key Lab of Genetic Engineering, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan University, Shanghai, 200438, PR China
| | - Pingzhao Zhang
- Fudan University Shanghai Cancer Center and Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China
| | - Yao Li
- Shanghai Stomatological Hospital & School of Stomatology, State Key Lab of Genetic Engineering, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan University, Shanghai, 200438, PR China
| | - Ren Mo
- Department of Urology, Inner Mongolia Urological Institute, Inner Mongolia Autonomous Region People's Hospital, Hohhot, 010017, Inner Mongolia, PR China.
| | - Kun Gao
- Department of Clinical Laboratory, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, 200092, PR China; Shanghai Key Laboratory of Maternal and Fetal Medicine, Shanghai First Maternity and Infant Hospital, Shanghai, 200092, PR China.
| | - Chenji Wang
- Shanghai Stomatological Hospital & School of Stomatology, State Key Lab of Genetic Engineering, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan University, Shanghai, 200438, PR China.
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8
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Li X, Chen K, Wang Z, Li J, Wang X, Xie C, Tong J, Shen Y. The mTOR signalling in corneal diseases: A recent update. Biochem Pharmacol 2023; 213:115620. [PMID: 37217140 DOI: 10.1016/j.bcp.2023.115620] [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: 03/23/2023] [Revised: 05/16/2023] [Accepted: 05/16/2023] [Indexed: 05/24/2023]
Abstract
Corneal diseases affect 4.2 million people worldwide and are a leading cause of vision impairment and blindness. Current treatments for corneal diseases, such as antibiotics, steroids, and surgical interventions, have numerous disadvantages and challenges. Thus, there is an urgent need for more effective therapies. Although the pathogenesis of corneal diseases is not fully understood, it is known that injury caused by various stresses and postinjury healing, such as epithelial renewal, inflammation, stromal fibrosis, and neovascularization, are highly involved. Mammalian target of rapamycin (mTOR) is a key regulator of cell growth, metabolism, and the immune response. Recent studies have revealed that activation of mTOR signalling extensively contributes to the pathogenesis of various corneal diseases, and inhibition of mTOR with rapamycin achieves promising outcomes, supporting the potential of mTOR as a therapeutic target. In this review, we detail the function of mTOR in corneal diseases and how these characteristics contribute to disease treatment using mTOR-targeted drugs.
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Affiliation(s)
- Xiang Li
- Department of Ophthalmology, the First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Kuangqi Chen
- Department of Ophthalmology, the First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Zixi Wang
- Bone Marrow Transplantation Center, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jiayuan Li
- Department of Ophthalmology, the First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Xiawei Wang
- Department of Ophthalmology, the First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Chen Xie
- Department of Ophthalmology, the First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang Province, China.
| | - Jianping Tong
- Department of Ophthalmology, the First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang Province, China.
| | - Ye Shen
- Department of Ophthalmology, the First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang Province, China.
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9
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Panigrahi L, Anjum S, Ahmed S. Critical role of Wat1/Pop3 in regulating the TORC1 signalling pathway in fission yeast S. pombe. Fungal Genet Biol 2023; 164:103764. [PMID: 36481249 DOI: 10.1016/j.fgb.2022.103764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 11/21/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022]
Abstract
The target of rapamycin (TOR), a major pathway for the regulation of cell growth and proliferation is conserved from yeast to humans. Fission yeast contains two tor complexes, TORC1 is crucial for cell growth while TORC2 gets activated under stress conditions. Pop3/Wat1, a mammalian Lst8 ortholog is an important component of both TOR complexes and has been implicated in the oxidative stress response pathway. Here in this study, the genetic interaction analysis revealed a synthetic lethal interaction of wat1 with tor2-287 mutant cells. Co-immunoprecipitation analysis revealed Wat1 interacts with TORC1 components Tor2, Mip1, and Tco89 while wat1-17 mutant protein fails to interact with these proteins. In the absence of Wat1, the cells arrest at G1 phase with reduced cell size at non-permissive temperature reminiscent of tor2-287 mutant phenotype. Similarly, inactivation of Wat1 results in the failure of TORC1 mediated phosphorylation of Psk1 and Rps602, leading to dysregulation of amino acid permeases and delocalization of Gaf1, a DNA binding transcription factor. Overall, we have hypothesized that Wat1/Pop3 is required to execute the function of TORC1.
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Affiliation(s)
- Lalita Panigrahi
- Biochemistry and Structural Biology Division, CSIR- Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow 226031, India
| | - Simmi Anjum
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shakil Ahmed
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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10
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Jhanwar-Uniyal M, Gellerson O, Bree J, Das M, Kleinman G, Gandhi CD. Defining the role of mTOR pathway in the regulation of stem cells of glioblastoma. Adv Biol Regul 2022; 88:100946. [PMID: 36658088 DOI: 10.1016/j.jbior.2022.100946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 01/01/2023]
Abstract
The mechanistic target of rapamycin (mTOR), a serine/threonine kinase, functions by forming two multiprotein complexes termed mTORC1 and mTORC2. Glioblastoma (GBM) is a uniformly fatal brain tumor that remains incurable partly due to the existence of untreatable cancer stem cells (CSC). The pathogenesis of GBM is largely due to the loss of the tumor suppressor gene PTEN, which is implicated in the aberrant activation of the mTOR pathway. The major cause of tumor recurrence, growth, and invasion is the presence of the unique population of CSC. Resistance to conventional therapies appears to be caused by both extensive genetic abnormalities and dysregulation of the transcription landscape. Consequently, CSCs have emerged as targets of interest in new treatment paradigms. Evidence suggests that inhibition of the mTOR pathway can also be applied to target CSCs. Here we explored the role of the mTOR pathway in the regulation of stem cells of GBM by treating them with inhibitors of canonical PI3K/AKT/mTOR pathways such as rapamycin (mTORC1 inhibitor), PP242 (ATP binding mTORC1/2 inhibitor), LY294002 (PI3K inhibitor), and MAPK inhibitor, U0126. A significant number of GBM tumors expressed stem cell marker nestin and activated mTOR (pmTORSer2448), with most tumor cells co-expressing both markers. The expression of stem cell marker NANOG was suppressed following rapamycin treatment. The neurospheres were disrupted following rapamycin and LY294002 treatments. Rapamycin or PP242 along with differentiating agent All-trans-retinoic acid reduced stem cell proliferation. Treatment with novel small molecule inhibitors of mTORC1/2 demonstrated that Torin1 and Torin2 suppressed the proliferation of GBM CSC, while XL388 was less effective. Torin1 and XL388 delay the process of self-renewal as compared to controls, whereas Torin2 halted self-renewal. Torin2 was able to eradicate tumor cells. In conclusion, Torin2 effectively targeted CSCs of GBM by halting self-renewal and inhibiting cell proliferation, underscoring the use of Torin2 in the treatment of GBM.
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Affiliation(s)
- Meena Jhanwar-Uniyal
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY, 10595, USA.
| | - Olivia Gellerson
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY, 10595, USA
| | - Julie Bree
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY, 10595, USA
| | - Mohan Das
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY, 10595, USA
| | - George Kleinman
- Department of Pathology, New York Medical College/Westchester Medical Center, Valhalla, NY, 10595, USA
| | - Chirag D Gandhi
- Department of Neurosurgery, New York Medical College/Westchester Medical Center, Valhalla, NY, 10595, USA
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11
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Frappaolo A, Karimpour-Ghahnavieh A, Cesare G, Sechi S, Fraschini R, Vaccari T, Giansanti MG. GOLPH3 protein controls organ growth by interacting with TOR signaling proteins in Drosophila. Cell Death Dis 2022; 13:1003. [PMID: 36435842 PMCID: PMC9701223 DOI: 10.1038/s41419-022-05438-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 11/28/2022]
Abstract
The oncoprotein GOLPH3 (Golgi phosphoprotein 3) is an evolutionarily conserved phosphatidylinositol 4-phosphate effector, mainly localized to the Golgi apparatus, where it supports organelle architecture and vesicular trafficking. Overexpression of human GOLPH3 correlates with poor prognosis in several cancer types and is associated with enhanced signaling downstream of mTOR (mechanistic target of rapamycin). However, the molecular link between GOLPH3 and mTOR remains elusive. Studies in Drosophila melanogaster have shown that Translationally controlled tumor protein (Tctp) and 14-3-3 proteins are required for organ growth by supporting the function of the small GTPase Ras homolog enriched in the brain (Rheb) during mTORC1 (mTOR complex 1) signaling. Here we demonstrate that Drosophila GOLPH3 (dGOLPH3) physically interacts with Tctp and 14-3-3ζ. RNAi-mediated knockdown of dGOLPH3 reduces wing and eye size and enhances the phenotypes of Tctp RNAi. This phenotype is partially rescued by overexpression of Tctp, 14-3-3ζ, or Rheb. We also show that the Golgi localization of Rheb in Drosophila cells depends on dGOLPH3. Consistent with dGOLPH3 involvement in Rheb-mediated mTORC1 activation, depletion of dGOLPH3 also reduces levels of phosphorylated ribosomal S6 kinase, a downstream target of mTORC1. Finally, the autophagy flux and the expression of autophagic transcription factors of the TFEB family, which anti correlates with mTOR signaling, are compromised upon reduction of dGOLPH3. Overall, our data provide the first in vivo demonstration that GOLPH3 regulates organ growth by directly associating with mTOR signaling proteins.
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Affiliation(s)
- Anna Frappaolo
- grid.7841.aIstituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
| | - Angela Karimpour-Ghahnavieh
- grid.7841.aIstituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
| | - Giuliana Cesare
- grid.4708.b0000 0004 1757 2822Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Stefano Sechi
- grid.7841.aIstituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
| | - Roberta Fraschini
- grid.7563.70000 0001 2174 1754Dipartimento di Biotecnologie e Bioscienze, Università degli studi di Milano Bicocca, 20126 Milano, Italy
| | - Thomas Vaccari
- grid.4708.b0000 0004 1757 2822Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milano, Italy
| | - Maria Grazia Giansanti
- grid.7841.aIstituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, 00185 Roma, Italy
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12
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Geng H, Feng C, Sun Z, Fan X, Xie Y, Gu J, Fan L, Liu G, Li C, Thorne RF, Zhang XD, Li X, Liu X. Chloride intracellular channel 1 promotes esophageal squamous cell carcinoma proliferation via mTOR signalling. Transl Oncol 2022; 27:101560. [PMID: 36252281 PMCID: PMC9579717 DOI: 10.1016/j.tranon.2022.101560] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVES To investigate the clinical significance of Chloride Intracellular Channel 1 (CLIC1) expression in esophageal squamous cell carcinoma (ESCC) and its functional contribution and molecular mechanisms to the progression of ESCC. METHODS CLIC1 expression was analyzed by immunohistochemistry (IHC) in a cohort of 86 ESCC tissue specimens and paired normal adjacent esophageal tissues. Associations between clinicopathological features of ESCC and CLIC1 expression were determined. In vitro analyses examined CLIC1 expression in the ESCC cell lines KYSE150 and TE1 using RT-PCR and Western blotting. The downstream pathways of CLIC1 were detected by lentiviral shRNA knockdown and subsequent proteomic analyses. CLIC1 siRNA knockdown was performed in ESCC cell lines KYSE150 and TE1 and the functional effects of CLIC1 on the growth and proliferation of ESCC cells were evaluated combined with cell viability and colony formation assays; the mTOR signaling pathway-related proteins were detected by Western blotting based on the previous proteomic data. RESULTS CLIC1 expression was significantly increased in ex vivo ESCC tissues compared with corresponding normal tissues, and the up-regulation was associated with clinical tumor node metastasis (TNM) classifications. Knockdown of CLIC1 inhibited in vitro cell proliferation of ESCC cell lines KYSE150 and TE1. CLIC1 knockdown down-regulated the protein expression of p-mTOR and the downstream targets Rictor and p-4EBP1 in both KYSE150 and TE1 cell lines. And the CLIC1 knockdown induced inhibition of cell proliferation on ESCC cells could be rescued by mTOR overexpression. CONCLUSIONS CLIC1 expression increases during esophageal carcinogenesis and it may functionally contribute to the progression of ESCC through growth promotion effects by promoting the mTOR and downstream signaling pathway. CLIC1 therefore constitutes a candidate molecular biomarker of ESCC.
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Affiliation(s)
- Huiwu Geng
- School of Life Sciences, Anhui Medical University, Hefei 230032, China
| | - Cheng Feng
- School of Life Sciences, Anhui Medical University, Hefei 230032, China
| | - Zhangran Sun
- School of Life Sciences, Anhui Medical University, Hefei 230032, China
| | - Xu Fan
- School of Life Sciences, Anhui Medical University, Hefei 230032, China
| | - Yiqing Xie
- School of Life Sciences, Anhui Medical University, Hefei 230032, China
| | - Jinghua Gu
- School of Life Sciences, Anhui Medical University, Hefei 230032, China
| | - Libin Fan
- School of Life Sciences, Anhui Medical University, Hefei 230032, China
| | - Gang Liu
- School of Life Sciences, Anhui Medical University, Hefei 230032, China
| | - Chao Li
- School of Life Sciences, Anhui Medical University, Hefei 230032, China
| | - Rick F. Thorne
- Henan International Joint Laboratory of Non-Coding RNA and Metabolism in Cancer, Henan Provincial Key Laboratory of Long Non-Coding RNA and Cancer Metabolism, Translational Research Institute of Henan Provincial People's Hospital and People's Hospital of Zhengzhou University, Henan 450053, China,School of Biomedical Sciences and Pharmacy, The University of Newcastle, Newcastle, NSW 2308, Australia
| | - Xu Dong Zhang
- Henan International Joint Laboratory of Non-Coding RNA and Metabolism in Cancer, Henan Provincial Key Laboratory of Long Non-Coding RNA and Cancer Metabolism, Translational Research Institute of Henan Provincial People's Hospital and People's Hospital of Zhengzhou University, Henan 450053, China,School of Biomedical Sciences and Pharmacy, The University of Newcastle, Newcastle, NSW 2308, Australia
| | - Xinying Li
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China,Corresponding author at: Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China.
| | - Xiaoying Liu
- School of Life Sciences, Anhui Medical University, Hefei 230032, China,Henan International Joint Laboratory of Non-Coding RNA and Metabolism in Cancer, Henan Provincial Key Laboratory of Long Non-Coding RNA and Cancer Metabolism, Translational Research Institute of Henan Provincial People's Hospital and People's Hospital of Zhengzhou University, Henan 450053, China,Corresponding author at: School of Life Sciences, Anhui Medical University, Hefei 230032, China. Research Institute of Henan Provincial People's Hospital and People's Hospital of Zhengzhou University, Henan 450053, China.
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13
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Pudewell S, Lissy J, Nakhaeizadeh H, Mosaddeghzadeh N, Nakhaei-Rad S, Dvorsky R, Ahmadian MR. New mechanistic insights into the RAS-SIN1 interaction at the membrane. Front Cell Dev Biol 2022; 10:987754. [PMID: 36274845 PMCID: PMC9583166 DOI: 10.3389/fcell.2022.987754] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Stress-activated MAP kinase-interacting protein 1 (SIN1) is a central member of the mTORC2 complex that contains an N-terminal domain (NTD), a conserved region in the middle (CRIM), a RAS-binding domain (RBD), and a pleckstrin homology domain. Recent studies provided valuable structural and functional insights into the interactions of SIN1 and the RAS-binding domain of RAS proteins. However, the mechanism for a reciprocal interaction of the RBD-PH tandem with RAS proteins and the membrane as an upstream event to spatiotemporal mTORC2 regulation is not clear. The biochemical assays in this study led to the following results: 1) all classical RAS paralogs, including HRAS, KRAS4A, KRAS4B, and NRAS, can bind to SIN1-RBD in biophysical and SIN1 full length (FL) in cell biology experiments; 2) the SIN1-PH domain modulates interactions with various types of membrane phosphoinositides and constantly maintains a pool of SIN1 at the membrane; and 3) a KRAS4A-dependent decrease in membrane binding of the SIN1-RBD-PH tandem was observed, suggesting for the first time a mechanistic influence of KRAS4A on SIN1 membrane association. Our study strengthens the current mechanistic understanding of SIN1-RAS interaction and suggests membrane interaction as a key event in the control of mTORC2-dependent and mTORC2-independent SIN1 function.
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Affiliation(s)
- Silke Pudewell
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jana Lissy
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Hossein Nakhaeizadeh
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Niloufar Mosaddeghzadeh
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Saeideh Nakhaei-Rad
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Stem Cell Biology and Regenerative Medicine Research Group, Institute of Biotechnology, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Radovan Dvorsky
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- Center for Interdisciplinary Biosciences, P. J. Šafárik University, Košice, Slovakia
| | - Mohammad R. Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- *Correspondence: Mohammad R. Ahmadian,
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14
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mTOR: A Potential New Target in Nonalcoholic Fatty Liver Disease. Int J Mol Sci 2022; 23:ijms23169196. [PMID: 36012464 PMCID: PMC9409235 DOI: 10.3390/ijms23169196] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 11/17/2022] Open
Abstract
The global prevalence of nonalcoholic fatty liver disease (NAFLD) continues to rise, yet effective treatments are lacking due to the complex pathogenesis of this disease. Although recent research has provided evidence for the “multiple strikes” theory, the classic “two strikes” theory has not been overturned. Therefore, there is a crucial need to identify multiple targets in NAFLD pathogenesis for the development of diagnostic markers and targeted therapeutics. Since its discovery, the mechanistic target of rapamycin (mTOR) has been recognized as the central node of a network that regulates cell growth and development and is closely related to liver lipid metabolism and other processes. This paper will explore the mechanisms by which mTOR regulates lipid metabolism (SREBPs), insulin resistance (Foxo1, Lipin1), oxidative stress (PIG3, p53, JNK), intestinal microbiota (TLRs), autophagy, inflammation, genetic polymorphisms, and epigenetics in NAFLD. The specific influence of mTOR on NAFLD was hypothesized to be divided into micro regulation (the mechanism of mTOR’s influence on NAFLD factors) and macro mediation (the relationship between various influencing factors) to summarize the influence of mTOR on the developmental process of NAFLD, and prove the importance of mTOR as an influencing factor of NAFLD regarding multiple aspects. The effects of crosstalk between mTOR and its upstream regulators, Notch, Hedgehog, and Hippo, on the occurrence and development of NAFLD-associated hepatocellular carcinoma are also summarized. This analysis will hopefully support the development of diagnostic markers and new therapeutic targets in NAFLD.
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15
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Luciano AK, Korobkina E, Lyons SP, Haley JA, Fluharty S, Jung SM, Kettenbach AN, Guertin DA. Proximity labeling of endogenous RICTOR identifies mTOR Complex 2 regulation by ADP ribosylation factor ARF1. J Biol Chem 2022; 298:102379. [PMID: 35973513 PMCID: PMC9513271 DOI: 10.1016/j.jbc.2022.102379] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 07/22/2022] [Accepted: 08/09/2022] [Indexed: 01/08/2023] Open
Abstract
Mechanistic target of rapamycin (mTOR) complex 2 (mTORC2) regulates metabolism, cell proliferation, and cell survival. mTORC2 activity is stimulated by growth factors, and it phosphorylates the hydrophobic motif site of the AGC kinases AKT, SGK, and PKC. However, the proteins that interact with mTORC2 to control its activity and localization remain poorly defined. To identify mTORC2-interacting proteins in living cells, we tagged endogenous RICTOR, an essential mTORC2 subunit, with the modified BirA biotin ligase BioID2 and performed live-cell proximity labeling. We identified 215 RICTOR-proximal proteins, including proteins with known mTORC2 pathway interactions, and 135 proteins (63%) not previously linked to mTORC2 signaling, including nuclear and cytoplasmic proteins. Our imaging and cell fractionation experiments suggest nearly 30% of RICTOR is in the nucleus, hinting at potential nuclear functions. We also identified 29 interactors containing RICTOR-dependent, insulin-stimulated phosphorylation sites, thus providing insight into mTORC2-dependent insulin signaling dynamics. Finally, we identify the endogenous ADP ribosylation factor 1 (ARF1) GTPase as an mTORC2-interacting protein. Through gain-of-function and loss-of-function studies, we provide functional evidence that ARF1 may negatively regulate mTORC2. In summary, we present a new method of studying endogenous mTORC2, a resource of RICTOR/mTORC2 protein interactions in living cells, and a potential mechanism of mTORC2 regulation by the ARF1 GTPase.
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Affiliation(s)
- Amelia K Luciano
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Ekaterina Korobkina
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Scott P Lyons
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - John A Haley
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Shelagh Fluharty
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Su Myung Jung
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - David A Guertin
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01605; Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605.
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16
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Pérez S, Rius-Pérez S. Macrophage Polarization and Reprogramming in Acute Inflammation: A Redox Perspective. Antioxidants (Basel) 2022; 11:antiox11071394. [PMID: 35883885 PMCID: PMC9311967 DOI: 10.3390/antiox11071394] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/07/2022] [Accepted: 07/15/2022] [Indexed: 12/12/2022] Open
Abstract
Macrophage polarization refers to the process by which macrophages can produce two distinct functional phenotypes: M1 or M2. The balance between both strongly affects the progression of inflammatory disorders. Here, we review how redox signals regulate macrophage polarization and reprogramming during acute inflammation. In M1, macrophages augment NADPH oxidase isoform 2 (NOX2), inducible nitric oxide synthase (iNOS), synaptotagmin-binding cytoplasmic RNA interacting protein (SYNCRIP), and tumor necrosis factor receptor-associated factor 6 increase oxygen and nitrogen reactive species, which triggers inflammatory response, phagocytosis, and cytotoxicity. In M2, macrophages down-regulate NOX2, iNOS, SYNCRIP, and/or up-regulate arginase and superoxide dismutase type 1, counteract oxidative and nitrosative stress, and favor anti-inflammatory and tissue repair responses. M1 and M2 macrophages exhibit different metabolic profiles, which are tightly regulated by redox mechanisms. Oxidative and nitrosative stress sustain the M1 phenotype by activating glycolysis and lipid biosynthesis, but by inhibiting tricarboxylic acid cycle and oxidative phosphorylation. This metabolic profile is reversed in M2 macrophages because of changes in the redox state. Therefore, new therapies based on redox mechanisms have emerged to treat acute inflammation with positive results, which highlights the relevance of redox signaling as a master regulator of macrophage reprogramming.
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17
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Wang Y, Fung NSK, Lam WC, Lo ACY. mTOR Signalling Pathway: A Potential Therapeutic Target for Ocular Neurodegenerative Diseases. Antioxidants (Basel) 2022; 11:antiox11071304. [PMID: 35883796 PMCID: PMC9311918 DOI: 10.3390/antiox11071304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 02/04/2023] Open
Abstract
Recent advances in the research of the mammalian target of the rapamycin (mTOR) signalling pathway demonstrated that mTOR is a robust therapeutic target for ocular degenerative diseases, including age-related macular degeneration (AMD), diabetic retinopathy (DR), and glaucoma. Although the exact mechanisms of individual ocular degenerative diseases are unclear, they share several common pathological processes, increased and prolonged oxidative stress in particular, which leads to functional and morphological impairment in photoreceptors, retinal ganglion cells (RGCs), or retinal pigment epithelium (RPE). mTOR not only modulates oxidative stress but is also affected by reactive oxygen species (ROS) activation. It is essential to understand the complicated relationship between the mTOR pathway and oxidative stress before its application in the treatment of retinal degeneration. Indeed, the substantial role of mTOR-mediated autophagy in the pathogenies of ocular degenerative diseases should be noted. In reviewing the latest studies, this article summarised the application of rapamycin, an mTOR signalling pathway inhibitor, in different retinal disease models, providing insight into the mechanism of rapamycin in the treatment of retinal neurodegeneration under oxidative stress. Besides basic research, this review also summarised and updated the results of the latest clinical trials of rapamycin in ocular neurodegenerative diseases. In combining the current basic and clinical research results, we provided a more complete picture of mTOR as a potential therapeutic target for ocular neurodegenerative diseases.
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18
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mTOR substrate phosphorylation in growth control. Cell 2022; 185:1814-1836. [PMID: 35580586 DOI: 10.1016/j.cell.2022.04.013] [Citation(s) in RCA: 117] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 12/20/2022]
Abstract
The target of rapamycin (TOR), discovered 30 years ago, is a highly conserved serine/threonine protein kinase that plays a central role in regulating cell growth and metabolism. It is activated by nutrients, growth factors, and cellular energy. TOR forms two structurally and functionally distinct complexes, TORC1 and TORC2. TOR signaling activates cell growth, defined as an increase in biomass, by stimulating anabolic metabolism while inhibiting catabolic processes. With emphasis on mammalian TOR (mTOR), we comprehensively reviewed the literature and identified all reported direct substrates. In the context of recent structural information, we discuss how mTORC1 and mTORC2, despite having a common catalytic subunit, phosphorylate distinct substrates. We conclude that the two complexes recruit different substrates to phosphorylate a common, minimal motif.
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19
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Huang WQ, Zou Y, Tian Y, Ma XF, Zhou QY, Li ZY, Gong SX, Wang AP. Mammalian Target of Rapamycin as the Therapeutic Target of Vascular Proliferative Diseases: Past, Present, and Future. J Cardiovasc Pharmacol 2022; 79:444-455. [PMID: 34983907 DOI: 10.1097/fjc.0000000000001208] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 12/16/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT The abnormal proliferation of vascular smooth muscle cells (VSMCs) is a key pathological characteristic of vascular proliferative diseases. Mammalian target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase that plays an important role in regulating cell growth, motility, proliferation, and survival, as well as gene expression in response to hypoxia, growth factors, and nutrients. Increasing evidence shows that mTOR also regulates VSMC proliferation in vascular proliferative diseases and that mTOR inhibitors, such as rapamycin, effectively restrain VSMC proliferation. However, the molecular mechanisms linking mTOR to vascular proliferative diseases remain elusive. In our review, we summarize the key roles of the mTOR and the recent discoveries in vascular proliferative diseases, focusing on the therapeutic potential of mTOR inhibitors to target the mTOR signaling pathway for the treatment of vascular proliferative diseases. In this study, we discuss mTOR inhibitors as promising candidates to prevent VSMC-associated vascular proliferative diseases.
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Affiliation(s)
- Wen-Qian Huang
- Institute of Clinical Research, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
- Department of Physiology, Institute of Neuroscience Research, Hengyang Key Laboratory of Neurodegeneration and Cognitive Impairment, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
| | - Yan Zou
- Department of Hand and Foot Surgery, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China ; and
| | - Ying Tian
- Institute of Clinical Research, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
| | - Xiao-Feng Ma
- Institute of Clinical Research, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
| | - Qin-Yi Zhou
- Institute of Clinical Research, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
- Department of Physiology, Institute of Neuroscience Research, Hengyang Key Laboratory of Neurodegeneration and Cognitive Impairment, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
| | - Zhen-Yu Li
- Institute of Clinical Research, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
- Department of Physiology, Institute of Neuroscience Research, Hengyang Key Laboratory of Neurodegeneration and Cognitive Impairment, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
| | - Shao-Xin Gong
- Department of Pathology, First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
| | - Ai-Ping Wang
- Institute of Clinical Research, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
- Department of Physiology, Institute of Neuroscience Research, Hengyang Key Laboratory of Neurodegeneration and Cognitive Impairment, Hengyang Medical School, University of South China, Hengyang, Hunan, PR China
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20
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Karlsen TR, Olsen MB, Kong XY, Yang K, Quiles-Jiménez A, Kroustallaki P, Holm S, Lines GT, Aukrust P, Skarpengland T, Bjørås M, Dahl TB, Nilsen H, Gregersen I, Halvorsen B. NEIL3-deficient bone marrow displays decreased hematopoietic capacity and reduced telomere length. Biochem Biophys Rep 2022; 29:101211. [PMID: 35079641 PMCID: PMC8777121 DOI: 10.1016/j.bbrep.2022.101211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 11/24/2022] Open
Abstract
Deficiency of NEIL3, a DNA repair enzyme, has significant impact on mouse physiology, including vascular biology and gut health, processes related to aging. Leukocyte telomere length (LTL) is suggested as a marker of biological aging, and shortened LTL is associated with increased risk of cardiovascular disease. NEIL3 has been shown to repair DNA damage in telomere regions in vitro. Herein, we explored the role of NEIL3 in telomere maintenance in vivo by studying bone marrow cells from atherosclerosis-prone NEIL3-deficient mice. We found shortened telomeres and decreased activity of the telomerase enzyme in bone marrow cells derived from Apoe -/- Neil3 -/- as compared to Apoe -/- mice. Furthermore, Apoe -/- Neil3 -/- mice had decreased leukocyte levels as compared to Apoe -/- mice, both in bone marrow and in peripheral blood. Finally, RNA sequencing of bone marrow cells from Apoe -/- Neil3 -/- and Apoe -/- mice revealed different expression levels of genes involved in cell cycle regulation, cellular senescence and telomere protection. This study points to NEIL3 as a telomere-protecting protein in murine bone marrow in vivo.
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Affiliation(s)
- Tom Rune Karlsen
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Maria B. Olsen
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Xiang Y. Kong
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Kuan Yang
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Ana Quiles-Jiménez
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Penelope Kroustallaki
- Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, Lørenskog, Norway
| | - Sverre Holm
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | | | - Pål Aukrust
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Tonje Skarpengland
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Magnar Bjørås
- Department of Microbiology, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Tuva B. Dahl
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Department of Research and Development, Division of Emergencies and Critical Care, Oslo University Hospital HF, Rikshospitalet, Norway
| | - Hilde Nilsen
- Department of Clinical Molecular Biology, University of Oslo and Akershus University Hospital, Lørenskog, Norway
| | - Ida Gregersen
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
| | - Bente Halvorsen
- Research Institute of Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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21
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Jhanwar-Uniyal M, Dominguez JF, Mohan AL, Tobias ME, Gandhi CD. Disentangling the signaling pathways of mTOR complexes, mTORC1 and mTORC2, as a therapeutic target in glioblastoma. Adv Biol Regul 2021; 83:100854. [PMID: 34996736 DOI: 10.1016/j.jbior.2021.100854] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 12/13/2022]
Abstract
Aberrant signaling of mechanistic target of rapamycin (mTOR' aka mammalian target of rapamycin) is shown to be linked to tumorigenesis of numerous malignancies including glioblastoma (GB). Glioblastoma mTOR is a serine threonine kinase that functions by forming two multiprotein complexes. There complexes are named mTORC1 and mTORC2 and downstream activated substrate execute cellular and metabolic functions. This signaling cascade of PI3K/AKT/mTOR is often upregulated due to frequent loss of the tumor suppressor PTEN, a phosphatase that functions antagonistically to PI3K. mTOR regulates cell growth, motility, and metabolism by forming two multiprotein complexes, mTORC1 and mTORC2, which are composed of special binding partners. These complexes are sensitive to distinct stimuli. mTORC1 is sensitive to nutrients and mTORC2 is regulated via PI3K and growth factor signaling. Since rapamycin and it's analogue are less effective in treatment of GB, we used novel ATP-competitive dual inhibitors of mTORC1 and mTORC2, namely, Torin1, Torin2, and XL388. Torin2 caused a concentration dependent pharmacodynamic effects on inhibition of phosphorylation of the mTORC1 substrates S6KSer235/236 and 4E-BP1Thr37/46 as well as the mTORC2 substrate AKTSer473 resulting in suppression of tumor cell proliferation and migration. Torin1 showed similar effects only at higher doses. Another small molecule compound, XL388 suppressed cell proliferation at a higher dose but failed to inhibit cell migration. Torin1 suppressed phosphorylation of PRAS40Thr246, however Torin2 completely abolished it. XL388 treatment inhibited the phosphorylation of PRAS40Thr246 at higher doses only. These findings underscore the use of novel compounds in treatment of cancer. In addition, formulation of third generation mTOR inhibitor "Rapalink-1" may provide new aspects to target mTOR pathways. Numerous inhibitors are currently being used in clinical trials that are aimed to target activated mTOR pathways.
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Affiliation(s)
- Meena Jhanwar-Uniyal
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY, 10595, USA.
| | - Jose F Dominguez
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY, 10595, USA
| | - Avinash L Mohan
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY, 10595, USA
| | - Michael E Tobias
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY, 10595, USA
| | - Chirag D Gandhi
- Department of Neurosurgery, Westchester Medical Center, New York Medical College, Valhalla, NY, 10595, USA
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22
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Ghomlaghi M, Yang G, Shin SY, James DE, Nguyen LK. Dynamic modelling of the PI3K/MTOR signalling network uncovers biphasic dependence of mTORC1 activity on the mTORC2 subunit SIN1. PLoS Comput Biol 2021; 17:e1008513. [PMID: 34529665 PMCID: PMC8478217 DOI: 10.1371/journal.pcbi.1008513] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 09/28/2021] [Accepted: 09/03/2021] [Indexed: 11/18/2022] Open
Abstract
The PI3K/MTOR signalling network regulates a broad array of critical cellular processes, including cell growth, metabolism and autophagy. The mechanistic target of rapamycin (MTOR) kinase functions as a core catalytic subunit in two physically and functionally distinct complexes mTORC1 and mTORC2, which also share other common components including MLST8 (also known as GβL) and DEPTOR. Despite intensive research, how mTORC1 and 2 assembly and activity are coordinated, and how they are functionally linked remain to be fully characterized. This is due in part to the complex network wiring, featuring multiple feedback loops and intricate post-translational modifications. Here, we integrate predictive network modelling, in vitro experiments and -omics data analysis to elucidate the emergent dynamic behaviour of the PI3K/MTOR network. We construct new mechanistic models that encapsulate critical mechanistic details, including mTORC1/2 coordination by MLST8 (de)ubiquitination and the Akt-to-mTORC2 positive feedback loop. Model simulations validated by experimental studies revealed a previously unknown biphasic, threshold-gated dependence of mTORC1 activity on the key mTORC2 subunit SIN1, which is robust against cell-to-cell variation in protein expression. In addition, our integrative analysis demonstrates that ubiquitination of MLST8, which is reversed by OTUD7B, is regulated by IRS1/2. Our results further support the essential role of MLST8 in enabling both mTORC1 and 2’s activity and suggest MLST8 as a viable therapeutic target in breast cancer. Overall, our study reports a new mechanistic model of PI3K/MTOR signalling incorporating MLST8-mediated mTORC1/2 formation and unveils a novel regulatory linkage between mTORC1 and mTORC2. Signalling networks are the key information-processing machineries that underpin the ability of living cells to respond proportionately to extra- (and intra-) cellular cues. The PI3K/MTOR signalling network is one of the most important signalling networks in human cells that regulates cellular response to critical hormones such as insulin; yet our understanding of the network behaviour remains far from complete. Here, we employed a highly integrative approach that combines predictive mathematical modelling, biological experimentation, and data analysis to gain novel systems-level insights into PI3K/MTOR signalling. We constructed new mathematical models of this complex network incorporating important regulatory mechanisms. In contrary to commonly-held views that mTORC2 lies upstream and is a positive regulator of mTORC1, we found that their relationship is highly non-linear and dose dependent. This finding has major implications for anti-mTORC2 therapy as depending on the cellular contexts, inhibiting mTORC2 may either reduce or enhance mTORC1 activation, the latter could inadvertently dampen the effect of mTORC2 blockade. Furthermore, our results demonstrate that MLST8 is required for the assembly and activity of both MTOR complexes and suggest MLST8 is a viable therapeutic target in breast cancer.
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Affiliation(s)
- Milad Ghomlaghi
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Guang Yang
- Charles Perkins Centre, School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Sung-Young Shin
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - David E James
- Charles Perkins Centre, School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Lan K Nguyen
- Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Melbourne, Australia.,Biomedicine Discovery Institute, Monash University, Melbourne, Australia
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23
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Abstract
Cells metabolize nutrients for biosynthetic and bioenergetic needs to fuel growth and proliferation. The uptake of nutrients from the environment and their intracellular metabolism is a highly controlled process that involves cross talk between growth signaling and metabolic pathways. Despite constant fluctuations in nutrient availability and environmental signals, normal cells restore metabolic homeostasis to maintain cellular functions and prevent disease. A central signaling molecule that integrates growth with metabolism is the mechanistic target of rapamycin (mTOR). mTOR is a protein kinase that responds to levels of nutrients and growth signals. mTOR forms two protein complexes, mTORC1, which is sensitive to rapamycin, and mTORC2, which is not directly inhibited by this drug. Rapamycin has facilitated the discovery of the various functions of mTORC1 in metabolism. Genetic models that disrupt either mTORC1 or mTORC2 have expanded our knowledge of their cellular, tissue, as well as systemic functions in metabolism. Nevertheless, our knowledge of the regulation and functions of mTORC2, particularly in metabolism, has lagged behind. Since mTOR is an important target for cancer, aging, and other metabolism-related pathologies, understanding the distinct and overlapping regulation and functions of the two mTOR complexes is vital for the development of more effective therapeutic strategies. This review discusses the key discoveries and recent findings on the regulation and metabolic functions of the mTOR complexes. We highlight findings from cancer models but also discuss other examples of the mTOR-mediated metabolic reprogramming occurring in stem and immune cells, type 2 diabetes/obesity, neurodegenerative disorders, and aging.
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Affiliation(s)
- Angelia Szwed
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey
| | - Eugene Kim
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey
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24
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Yin S, Liu L, Gan W. The Roles of Post-Translational Modifications on mTOR Signaling. Int J Mol Sci 2021; 22:ijms22041784. [PMID: 33670113 PMCID: PMC7916890 DOI: 10.3390/ijms22041784] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a master regulator of cell growth, proliferation, and metabolism by integrating various environmental inputs including growth factors, nutrients, and energy, among others. mTOR signaling has been demonstrated to control almost all fundamental cellular processes, such as nucleotide, protein and lipid synthesis, autophagy, and apoptosis. Over the past fifteen years, mapping the network of the mTOR pathway has dramatically advanced our understanding of its upstream and downstream signaling. Dysregulation of the mTOR pathway is frequently associated with a variety of human diseases, such as cancers, metabolic diseases, and cardiovascular and neurodegenerative disorders. Besides genetic alterations, aberrancies in post-translational modifications (PTMs) of the mTOR components are the major causes of the aberrant mTOR signaling in a number of pathologies. In this review, we summarize current understanding of PTMs-mediated regulation of mTOR signaling, and also update the progress on targeting the mTOR pathway and PTM-related enzymes for treatment of human diseases.
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25
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Scaiola A, Mangia F, Imseng S, Boehringer D, Berneiser K, Shimobayashi M, Stuttfeld E, Hall MN, Ban N, Maier T. The 3.2-Å resolution structure of human mTORC2. SCIENCE ADVANCES 2020; 6:6/45/eabc1251. [PMID: 33158864 PMCID: PMC7673708 DOI: 10.1126/sciadv.abc1251] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 09/22/2020] [Indexed: 05/22/2023]
Abstract
The protein kinase mammalian target of rapamycin (mTOR) is the central regulator of cell growth. Aberrant mTOR signaling is linked to cancer, diabetes, and neurological disorders. mTOR exerts its functions in two distinct multiprotein complexes, mTORC1 and mTORC2. Here, we report a 3.2-Å resolution cryo-EM reconstruction of mTORC2. It reveals entangled folds of the defining Rictor and the substrate-binding SIN1 subunits, identifies the carboxyl-terminal domain of Rictor as the source of the rapamycin insensitivity of mTORC2, and resolves mechanisms for mTORC2 regulation by complex destabilization. Two previously uncharacterized small-molecule binding sites are visualized, an inositol hexakisphosphate (InsP6) pocket in mTOR and an mTORC2-specific nucleotide binding site in Rictor, which also forms a zinc finger. Structural and biochemical analyses suggest that InsP6 and nucleotide binding do not control mTORC2 activity directly but rather have roles in folding or ternary interactions. These insights provide a firm basis for studying mTORC2 signaling and for developing mTORC2-specific inhibitors.
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Affiliation(s)
- Alain Scaiola
- Institute for Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Francesca Mangia
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Stefan Imseng
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | | | - Karolin Berneiser
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Mitsugu Shimobayashi
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Edward Stuttfeld
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Michael N Hall
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Nenad Ban
- Institute for Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
| | - Timm Maier
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
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26
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Kim LC, Rhee CH, Chen J. RICTOR Amplification Promotes NSCLC Cell Proliferation through Formation and Activation of mTORC2 at the Expense of mTORC1. Mol Cancer Res 2020; 18:1675-1684. [PMID: 32801163 PMCID: PMC7642103 DOI: 10.1158/1541-7786.mcr-20-0262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/10/2020] [Accepted: 08/07/2020] [Indexed: 11/16/2022]
Abstract
Non-small cell lung cancer (NSCLC) is characterized by genomic alterations, yet a targetable mutation has not been discovered in nearly half of all patients. Recent studies have identified amplification of RICTOR, an mTORC2-specific cofactor, as a novel actionable target in NSCLC. mTORC2 is one of two distinct mTOR complexes to sense environmental cues and regulate a variety of cellular processes, including cell growth, proliferation, and metabolism, all of which promote tumorigenesis when aberrantly regulated. Interestingly, other components of mTORC2 are not coamplified with RICTOR in human lung cancer, raising the question as to whether RICTOR amplification-induced changes are dependent on mTORC2 function. To model RICTOR amplification, we overexpressed Rictor using the Cas9 Synergistic Activation Mediator system. Overexpression of Rictor increased mTORC2 integrity and signaling, but at the expense of mTORC1, suggesting that overexpressed Rictor recruits common components away from mTORC1. Additionally, Rictor overexpression increases the proliferation and growth of NSCLC 3D cultures and tumors in vivo. Conversely, knockout of RICTOR leads to decreased mTORC2 formation and activity, but increased mTORC1 function. Because Rictor has mTOR-dependent and -independent functions, we also knocked out mLST8, a shared mTOR cofactor but is specifically required for mTORC2 function. Inducible loss of mLST8 in RICTOR-amplified NSCLC cells inhibited mTORC2 integrity and signaling, tumor cell proliferation, and tumor growth. Collectively, these data identify a mechanism for Rictor-driven tumor progression and provide further rationale for the development of an mTORC2-specific inhibitor. IMPLICATIONS: RICTOR amplification drives NSCLC proliferation through formation of mTORC2, suggesting mTORC2-specific inhibition could be a beneficial therapeutic option.
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Affiliation(s)
- Laura C Kim
- Program in Cancer Biology, Vanderbilt University, Nashville, Tennessee
| | | | - Jin Chen
- Program in Cancer Biology, Vanderbilt University, Nashville, Tennessee.
- Division of Rheumatology and Immunology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
- Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, Tennessee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee
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27
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Fu W, Hall MN. Regulation of mTORC2 Signaling. Genes (Basel) 2020; 11:E1045. [PMID: 32899613 PMCID: PMC7564249 DOI: 10.3390/genes11091045] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 08/31/2020] [Accepted: 09/02/2020] [Indexed: 12/12/2022] Open
Abstract
Mammalian target of rapamycin (mTOR), a serine/threonine protein kinase and a master regulator of cell growth and metabolism, forms two structurally and functionally distinct complexes, mTOR complex 1 (mTORC1) and mTORC2. While mTORC1 signaling is well characterized, mTORC2 is relatively poorly understood. mTORC2 appears to exist in functionally distinct pools, but few mTORC2 effectors/substrates have been identified. Here, we review recent advances in our understanding of mTORC2 signaling, with particular emphasis on factors that control mTORC2 activity.
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Affiliation(s)
- Wenxiang Fu
- Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming 650500, China
- Biozentrum, University of Basel, CH4056 Basel, Switzerland;
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28
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Feng G, Cai J, Huang Y, Zhu X, Gong B, Yang Z, Yan C, Hu Z, Yang L, Wang Z. G-Protein-Coupled Estrogen Receptor 1 Promotes Gender Disparities in Hepatocellular Carcinoma via Modulation of SIN1 and mTOR Complex 2 Activity. Mol Cancer Res 2020; 18:1863-1875. [PMID: 32873626 DOI: 10.1158/1541-7786.mcr-20-0173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 06/30/2020] [Accepted: 08/25/2020] [Indexed: 11/16/2022]
Abstract
Due to its intricate heterogeneity and limited treatment, hepatocellular carcinoma (HCC) has been considered a major cause of cancer-related mortality worldwide. Increasing evidence indicates that G-protein-coupled estrogen receptor 1 (GPER1) can promote estrogen-dependent hepatocellular proliferation by activating AKT signaling. The mTOR complex 2 (mTORC2), whose integrity and activity are modulated by its subunit Sin1, controls the activation of AKT by phosphorylation at position S473. In this study, we investigate the modulation of Sin1 and how estrogen signaling may influence the mTORC2-AKT cascade in HCC cells and a DEN-induced mouse model. We have found that estradiol-dependent Sin1 expression is transcriptionally modulated by GPER1 as well as ERα. GPER1 is able to regulate Sin1 stability via nuclear translocation, therefore increasing Sin1-mTORC2-AKT activation. Moreover, Sin1 interacts with ERα and further enhances its transcriptional activity. Sin1 is highly expressed in acute liver injury and in cases of HCC harboring high expression of GPER1 and constitutive activation of mTORC2-AKT signaling. GPER1 inhibition using the antagonist G-15 reverses DEN-induced acute liver injury by suppressing Sin1 expression and mTORC2-AKT activation. Notably, SIN1 expression varies between male and female mice in the context of both liver injury and liver cancer. In addition, high SIN1 expression is predictive of good prognosis in both male and female patients with HCC who are free from hepatitis virus infection and who report low alcohol consumption. Hence, here we demonstrate that Sin1 can be regulated by GPER1 both through nongenomic and indirect genomic signaling. IMPLICATIONS: This study suggests that Sin1 may be a novel HCC biomarker which is gender-dependent and sensitive to particular risk factor.
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Affiliation(s)
- Guanying Feng
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Jingshu Cai
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Yunchuanxiang Huang
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Xianjun Zhu
- Key Laboratory for Human Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Bo Gong
- Key Laboratory for Human Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Zhenglin Yang
- Key Laboratory for Human Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Chunhong Yan
- Georgia Cancer Center, Augusta University, Augusta, Georgia
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Zhuowei Hu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lu Yang
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
| | - Ziyan Wang
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
- Key Laboratory for Human Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
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29
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Yu XN, Shen XZ, Guo HY, Zhu JM. ASO Author Reflections: mLST8 is a Prognostic Biomarker and Involved in Tumor Progression in Hepatocellular Carcinoma. Ann Surg Oncol 2020; 27:1558-1559. [DOI: 10.1245/s10434-020-08275-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Indexed: 08/30/2023]
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30
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Liu GY, Sabatini DM. mTOR at the nexus of nutrition, growth, ageing and disease. Nat Rev Mol Cell Biol 2020; 21:183-203. [PMID: 31937935 PMCID: PMC7102936 DOI: 10.1038/s41580-019-0199-y] [Citation(s) in RCA: 1302] [Impact Index Per Article: 325.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2019] [Indexed: 12/21/2022]
Abstract
The mTOR pathway integrates a diverse set of environmental cues, such as growth factor signals and nutritional status, to direct eukaryotic cell growth. Over the past two and a half decades, mapping of the mTOR signalling landscape has revealed that mTOR controls biomass accumulation and metabolism by modulating key cellular processes, including protein synthesis and autophagy. Given the pathway's central role in maintaining cellular and physiological homeostasis, dysregulation of mTOR signalling has been implicated in metabolic disorders, neurodegeneration, cancer and ageing. In this Review, we highlight recent advances in our understanding of the complex regulation of the mTOR pathway and discuss its function in the context of physiology, human disease and pharmacological intervention.
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Affiliation(s)
- Grace Y Liu
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute, Cambridge, MA, USA
- The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
- Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Broad Institute, Cambridge, MA, USA.
- The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA, USA.
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31
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Yu XN, Zhang GC, Sun JL, Zhu HR, Shi X, Song GQ, Weng SQ, Dong L, Liu TT, Shen XZ, Guo HY, Zhu JM. Enhanced mLST8 Expression Correlates with Tumor Progression in Hepatocellular Carcinoma. Ann Surg Oncol 2020; 27:1546-1557. [PMID: 32157528 DOI: 10.1245/s10434-020-08263-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Indexed: 12/24/2022]
Abstract
BACKGROUND The mechanistic target of rapamycin (mTOR) pathway, containing mTOR complex 1 (mTORC1) and mTORC2, is dysregulated in multiple cancers, including hepatocellular carcinoma (HCC). Mammalian lethal with sec-13 protein 8 (mLST8) is a shared constituent of both mTORC1 and mTORC2, yet little is known regarding its role in HCC development. METHODS mLST8 expression was detected in a total of 186 pairs of HCC and adjacent non-tumor specimens. The correlation between mLST8 level and clinicopathological features or prognostic significance were analyzed. The role of mLST8 on biological functions was also preliminarily studied. RESULTS The study revealed that the mLST8 level was dramatically higher in HCC specimens than in adjacent non-tumor specimens. mLST8 overexpression positively correlated with tumor size, differentiation, and vessel invasion. Cases with elevated mLST8 level had more unfavorable overall survival (OS) and disease-free survival (DFS) than those with downregulated mLST8 level. Multivariate analysis demonstrated that mLST8 upregulation was an independent predictive marker for OS and DFS. Calibration curves from nomogram models indicated an excellent coherence between nomogram prediction and actual situation. Decision curve analysis proved that mLST8-based nomograms presented much higher predictive accuracy when compared with conventional clinical staging systems. Mechanistically, mLST8 enhanced cell proliferation and invasion through the AKT (protein kinase B) pathway. CONCLUSIONS Our study demonstrates that mLST8 exerts an oncogenic role in HCC and may become a promising prognostic biomarker and therapeutic target for HCC patients.
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Affiliation(s)
- Xiang-Nan Yu
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China
| | - Guang-Cong Zhang
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China
| | - Jia-Lei Sun
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China
| | - Hai-Rong Zhu
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China
| | - Xuan Shi
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China
| | - Guang-Qi Song
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China
| | - Shu-Qiang Weng
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China
| | - Ling Dong
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China
| | - Tao-Tao Liu
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China
| | - Xi-Zhong Shen
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China.,Shanghai Institute of Liver Disease, Shanghai, China.,Key Laboratory of Medical Molecular Virology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Hong-Ying Guo
- Department of Severe Hepatitis, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.
| | - Ji-Min Zhu
- Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China. .,Shanghai Institute of Liver Disease, Shanghai, China.
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32
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Huang Y, Feng G, Cai J, Peng Q, Yang Z, Yan C, Yang L, Wang Z. Sin1 promotes proliferation and invasion of prostate cancer cells by modulating mTORC2-AKT and AR signaling cascades. Life Sci 2020; 248:117449. [PMID: 32088212 DOI: 10.1016/j.lfs.2020.117449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/09/2020] [Accepted: 02/17/2020] [Indexed: 12/29/2022]
Abstract
AIMS Prostate cancer (PCa) is the most common type of cancer and a major cause of death in men worldwide. Aberrant Androgen receptor (AR) and PI3K-AKT signaling are very frequent in PCa patients and, therefore, considered as therapeutic targets in the clinic. Sin1 is an essential component of mTORC2 complex, which determines full AKT activation and PCa development in PTEN-/- mice. Here we examined the role of Sin1 in human PCa cell lines and respective tumor samples. MAIN METHODS Western blotting and immunohistochemistry (IHC) were performed to analyze the expression of Sin1-mTORC2-AKT related proteins in human PCa cells, as well as prostate tumors and normal tissue counterparts. Cell viability and invasion assays were also pursued in the presence or not of Sin1 in PCa cells. Immunoprecipitation assays were additionally carried out to examine the interaction of Sin1 with AR. KEY FINDINGS We have presently demonstrated that high levels of Sin1 expression in human PCa tissues correlate with cancer progression. Sin1-mediated cell proliferation and invasion of PCa cells occurs by regulating mTORC2-AKT signaling, epithelial-mesenchymal transition and matrix metalloproteinases. Moreover, androgens are able to induce Sin1 expression, which is further translocated to the nucleus of PCa cells. Finally, Sin1 interacts with AR to suppress its transcriptional activity. SIGNIFICANCE Taken together, these data indicate that both Sin1-mediated mTORC2-AKT signaling and Sin1-AR interaction regulate PCa development. Hence, Sin1 may be considered a novel biomarker of PCa progression.
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Affiliation(s)
- Yunchuanxiang Huang
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Guanying Feng
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Jingshu Cai
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Qian Peng
- Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Zhenglin Yang
- Key Laboratory for Human Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China; Research Unit for Blindness Prevention of Chinese Academy of Medical Science (2019RU026), Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Chengdu, Sichuan, China
| | - Chunhong Yan
- Georgia Cancer Center, Augusta University, Augusta, GA, USA; Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Lu Yang
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
| | - Ziyan Wang
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China; Key Laboratory for Human Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China; Research Unit for Blindness Prevention of Chinese Academy of Medical Science (2019RU026), Sichuan Academy of Medical Science & Sichuan Provincial People's Hospital, Chengdu, Sichuan, China.
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33
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Santos de Oliveira FL, Vieira Carletti J, Azevedo FFN, Freitas de Sousa FJ, Caetano EWS, Freire VN, Zanatta G. mTOR–mLST8 interaction: hot spot identification through quantum biochemistry calculations. NEW J CHEM 2020. [DOI: 10.1039/d0nj04099a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Quantum calculation of mTOR–mLST8 interaction.
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Affiliation(s)
| | | | | | | | | | | | - Geancarlo Zanatta
- Department of Physics at Federal University of Ceará
- 60455-760 Fortaleza
- Brazil
- Postgraduate Research Program in Biochemistry at Federal University of Ceará
- Fortaleza
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