1
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Bastos IM, Rebelo S, Silva VLM. A comprehensive review on phosphatidylinositol-3-kinase (PI3K) and its inhibitors bearing pyrazole or indazole core for cancer therapy. Chem Biol Interact 2024; 398:111073. [PMID: 38823538 DOI: 10.1016/j.cbi.2024.111073] [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: 04/29/2024] [Accepted: 05/27/2024] [Indexed: 06/03/2024]
Abstract
Cancer is a complex and multifaceted group of diseases with a high mortality rate characterized by uncontrolled proliferation of abnormal cells. Dysregulation of normal signalling pathways in cancer contributes to the different hallmarks of this disease. The signalling pathway of which phosphatidylinositol 3-kinase (PI3K) is a part is not an exception. In fact, dysregulated activation of PI3K signalling pathways can result in unbridled cellular proliferation and enhanced cell survival, thereby fostering the onset and advancement of cancer. Therefore, there is substantial interest in developing targeted therapies specifically aimed at inhibiting the PI3K enzyme and its associated pathways. Also, the therapeutic interest on pyrazoles and indazoles has been growing due to their various medicinal properties, namely, anticancer activity. Derivatives of these compounds have been studied as PI3K inhibitors, and they showed promising results. There are already some PI3K inhibitors approved by Food and Drug Administration (FDA), such as Idelalisib (Zydelig®) and Alpelisib (Piqray®). In this context, this review aims to address the importance of PI3K in cellular processes and its role in cancer. Additionally, it aims to report a comprehensive literature review of PI3K inhibitors, containing the pyrazole and indazole scaffolds, published in the last fifteen years, focusing on structure-activity relationship aspects, thus providing important insights for the design of novel and more effective PI3K inhibitors.
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Affiliation(s)
- Inês M Bastos
- LAQV-REQUIMTE and Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Sandra Rebelo
- Institute of Biomedicine-iBiMED, Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Vera L M Silva
- LAQV-REQUIMTE and Department of Chemistry, University of Aveiro, 3810-193, Aveiro, Portugal.
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2
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Fomo KN, Perumal N, Manicam C, Pfeiffer N, Grus FH. Neuroretinal Cell Culture Model as a Tool for the Development of New Therapeutic Approaches for Oxidative Stress-Induced Ocular Diseases, with a Focus on Glaucoma. Cells 2024; 13:775. [PMID: 38727311 PMCID: PMC11083839 DOI: 10.3390/cells13090775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/15/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024] Open
Abstract
Glaucoma is a heterogeneous group of optic neuropathies characterized by a progressive degeneration of the retinal ganglion cells (RGCs), leading to irreversible vision loss. Nowadays, the traditional therapeutic approach to glaucoma consists of lowering the intraocular pressure (IOP), which does not address the neurodegenerative features of the disease. Besides animal models of glaucoma, there is a considerable need for in vitro experimental models to propose new therapeutic strategies for this ocular disease. In this study, we elucidated the pathological mechanisms leading to neuroretinal R28 cell death after exposure to glutamate and hydrogen peroxide (H2O2) in order to develop new therapeutic approaches for oxidative stress-induced retinal diseases, including glaucoma. We were able to show that glutamate and H2O2 can induce a decrease in R28 cell viability in a concentration-dependent manner. A cell viability of about 42% was found after exposure to 3 mM of glutamate and about 56% after exposure to 100 µM of H2O2 (n = 4). Label-free quantitative mass spectrometry analysis revealed differential alterations of 193 and 311 proteins in R28 cells exposed to 3 mM of glutamate and 100 µM of H2O2, respectively (FDR < 1%; p < 0.05). Bioinformatics analysis indicated that the protein changes were associated with the dysregulation of signaling pathways, which was similar to those observed in glaucoma. Thus, the proteomic alteration induced by glutamate was associated with the inhibition of the PI3K/AKT signaling pathway. On the other hand, H2O2-induced toxicity in R28 cells was linked to the activation of apoptosis signaling and the inhibition of the mTOR and ERK/MAPK signaling pathways. Furthermore, the data show a similarity in the inhibition of the EIF2 and AMPK signaling pathways and the activation of the sumoylation and WNT/β-catenin signaling pathways in both groups. Our findings suggest that the exposure of R28 cells to glutamate and H2O2 could induce glaucoma-like neurodegenerative features and potentially provide a suitable tool for the development of new therapeutic strategies for retinal diseases.
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Affiliation(s)
| | | | | | | | - Franz H. Grus
- Experimental and Translational Ophthalmology, Department of Ophthalmology, University Medical Centre of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany; (K.N.F.); (N.P.); (C.M.); (N.P.)
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3
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Lee KY. Membrane-Driven Dimerization of the Peripheral Membrane Protein KRAS: Implications for Downstream Signaling. Int J Mol Sci 2024; 25:2530. [PMID: 38473778 DOI: 10.3390/ijms25052530] [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: 12/15/2023] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 03/14/2024] Open
Abstract
Transient homo-dimerization of the RAS GTPase at the plasma membrane has been shown to promote the mitogen-activated protein kinase (MAPK) signaling pathway essential for cell proliferation and oncogenesis. To date, numerous crystallographic studies have focused on the well-defined GTPase domains of RAS isoforms, which lack the disordered C-terminal membrane anchor, thus providing limited structural insight into membrane-bound RAS molecules. Recently, lipid-bilayer nanodisc platforms and paramagnetic relaxation enhancement (PRE) analyses have revealed several distinct structures of the membrane-anchored homodimers of KRAS, an isoform that is most frequently mutated in human cancers. The KRAS dimerization interface is highly plastic and altered by biologically relevant conditions, including oncogenic mutations, the nucleotide states of the protein, and the lipid composition. Notably, PRE-derived structures of KRAS homodimers on the membrane substantially differ in terms of the relative orientation of the protomers at an "α-α" dimer interface comprising two α4-α5 regions. This interface plasticity along with the altered orientations of KRAS on the membrane impact the accessibility of KRAS to downstream effectors and regulatory proteins. Further, nanodisc platforms used to drive KRAS dimerization can be used to screen potential anticancer drugs that target membrane-bound RAS dimers and probe their structural mechanism of action.
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Affiliation(s)
- Ki-Young Lee
- Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Sciences, CHA University, Pocheon-si 11160, Gyeonggi-Do, Republic of Korea
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4
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Geißert R, Lammert A, Wirth S, Hönig R, Lohfink D, Unger M, Pek D, Schlüter K, Scheftschik T, Smit DJ, Jücker M, Menke A, Giehl K. K-Ras(V12) differentially affects the three Akt isoforms in lung and pancreatic carcinoma cells and upregulates E-cadherin and NCAM via Akt3. Cell Commun Signal 2024; 22:85. [PMID: 38291468 PMCID: PMC10826106 DOI: 10.1186/s12964-024-01484-2] [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: 08/22/2023] [Accepted: 01/08/2024] [Indexed: 02/01/2024] Open
Abstract
K-Ras is the most frequently mutated Ras variant in pancreatic, colon and non-small cell lung adenocarcinoma. Activating mutations in K-Ras result in increased amounts of active Ras-GTP and subsequently a hyperactivation of effector proteins and downstream signaling pathways. Here, we demonstrate that oncogenic K-Ras(V12) regulates tumor cell migration by activating the phosphatidylinositol 3-kinases (PI3-K)/Akt pathway and induces the expression of E-cadherin and neural cell adhesion molecule (NCAM) by upregulation of Akt3. In vitro interaction and co-precipitation assays identified PI3-Kα as a bona fide effector of active K-Ras4B but not of H-Ras or N-Ras, resulting in enhanced Akt phosphorylation. Moreover, K-Ras(V12)-induced PI3-K/Akt activation enhanced migration in all analyzed cell lines. Interestingly, Western blot analyses with Akt isoform-specific antibodies as well as qPCR studies revealed, that the amount and the activity of Akt3 was markedly increased whereas the amount of Akt1 and Akt2 was downregulated in EGFP-K-Ras(V12)-expressing cell clones. To investigate the functional role of each Akt isoform and a possible crosstalk of the isoforms in more detail, each isoform was stably depleted in PANC-1 pancreatic and H23 lung carcinoma cells. Akt3, the least expressed Akt isoform in most cell lines, is especially upregulated and active in Akt2-depleted cells. Since expression of EGFP-K-Ras(V12) reduced E-cadherin-mediated cell-cell adhesion by induction of polysialylated NCAM, Akt3 was analyzed as regulator of E-cadherin and NCAM. Western blot analyses revealed pronounced reduction of E-cadherin and NCAM in the Akt3-kd cells, whereas Akt1 and Akt2 depletion upregulated E-cadherin, especially in H23 lung carcinoma cells. In summary, we identified oncogenic K-Ras4B as a key regulator of PI3-Kα-Akt signaling and Akt3 as a crucial regulator of K-Ras4B-induced modulation of E-cadherin and NCAM expression and localization.
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Affiliation(s)
- Rebekka Geißert
- Signal Transduction of Cellular Motility, Internal Medicine IV, Science Unit for Basic and Clinical Medicine, Justus Liebig University Giessen, Aulweg 128, D-35392, Giessen, Germany
| | - Angela Lammert
- Signal Transduction of Cellular Motility, Internal Medicine IV, Science Unit for Basic and Clinical Medicine, Justus Liebig University Giessen, Aulweg 128, D-35392, Giessen, Germany
| | - Stefanie Wirth
- Signal Transduction of Cellular Motility, Internal Medicine IV, Science Unit for Basic and Clinical Medicine, Justus Liebig University Giessen, Aulweg 128, D-35392, Giessen, Germany
| | - Rabea Hönig
- Signal Transduction of Cellular Motility, Internal Medicine IV, Science Unit for Basic and Clinical Medicine, Justus Liebig University Giessen, Aulweg 128, D-35392, Giessen, Germany
| | - Dirk Lohfink
- Molecular Oncology of Solid Tumors, Internal Medicine IV, Justus Liebig University Giessen, Aulweg 128, D-35392, Giessen, Germany
| | - Monika Unger
- Institute of Pharmacology and Toxicology, University of Ulm, D-89069, Ulm, Germany
| | - Denis Pek
- Institute of Pharmacology and Toxicology, University of Ulm, D-89069, Ulm, Germany
| | - Konstantin Schlüter
- Signal Transduction of Cellular Motility, Internal Medicine IV, Science Unit for Basic and Clinical Medicine, Justus Liebig University Giessen, Aulweg 128, D-35392, Giessen, Germany
| | - Theresa Scheftschik
- Molecular Oncology of Solid Tumors, Internal Medicine IV, Justus Liebig University Giessen, Aulweg 128, D-35392, Giessen, Germany
| | - Daniel J Smit
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, D-20246, Hamburg, Germany
| | - Manfred Jücker
- Institute of Biochemistry and Signal Transduction, University Medical Center Hamburg-Eppendorf, D-20246, Hamburg, Germany
| | - Andre Menke
- Molecular Oncology of Solid Tumors, Internal Medicine IV, Justus Liebig University Giessen, Aulweg 128, D-35392, Giessen, Germany
| | - Klaudia Giehl
- Signal Transduction of Cellular Motility, Internal Medicine IV, Science Unit for Basic and Clinical Medicine, Justus Liebig University Giessen, Aulweg 128, D-35392, Giessen, Germany.
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5
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Nussinov R, Liu Y, Zhang W, Jang H. Protein conformational ensembles in function: roles and mechanisms. RSC Chem Biol 2023; 4:850-864. [PMID: 37920394 PMCID: PMC10619138 DOI: 10.1039/d3cb00114h] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/02/2023] [Indexed: 11/04/2023] Open
Abstract
The sequence-structure-function paradigm has dominated twentieth century molecular biology. The paradigm tacitly stipulated that for each sequence there exists a single, well-organized protein structure. Yet, to sustain cell life, function requires (i) that there be more than a single structure, (ii) that there be switching between the structures, and (iii) that the structures be incompletely organized. These fundamental tenets called for an updated sequence-conformational ensemble-function paradigm. The powerful energy landscape idea, which is the foundation of modernized molecular biology, imported the conformational ensemble framework from physics and chemistry. This framework embraces the recognition that proteins are dynamic and are always interconverting between conformational states with varying energies. The more stable the conformation the more populated it is. The changes in the populations of the states are required for cell life. As an example, in vivo, under physiological conditions, wild type kinases commonly populate their more stable "closed", inactive, conformations. However, there are minor populations of the "open", ligand-free states. Upon their stabilization, e.g., by high affinity interactions or mutations, their ensembles shift to occupy the active states. Here we discuss the role of conformational propensities in function. We provide multiple examples of diverse systems, including protein kinases, lipid kinases, and Ras GTPases, discuss diverse conformational mechanisms, and provide a broad outlook on protein ensembles in the cell. We propose that the number of molecules in the active state (inactive for repressors), determine protein function, and that the dynamic, relative conformational propensities, rather than the rigid structures, are the hallmark of cell life.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University Tel Aviv 69978 Israel
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Wengang Zhang
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
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6
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Zhang Y, Wang Y, Zhang B, Li P, Zhao Y. Methods and biomarkers for early detection, prediction, and diagnosis of colorectal cancer. Biomed Pharmacother 2023; 163:114786. [PMID: 37119736 DOI: 10.1016/j.biopha.2023.114786] [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: 02/22/2023] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 05/01/2023] Open
Abstract
Colorectal cancer (CRC) is one of the most common digestive diseases worldwide. It has steadily ascended to the top three cancers in terms of incidence and mortality. The primary cause is the inability to diagnose it at an early stage. Therefore, early detection and diagnosis are essential for colorectal cancer prevention. Although there are now various methods for CRC early detection, in addition to recent developments in surgical and multimodal therapy, the poor prognosis and late detection of CRC still remain significant. Thus, it is important to investigate novel technologies and biomarkers to improve the sensitization and specification of CRC diagnosis. Here, we present some common methods and biomarkers for early detection and diagnosis of CRC, we hope this review will encourage the adoption of screening programs and the clinical use of these potential molecules as biomarkers for CRC early detection and prognosis.
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Affiliation(s)
- Yue Zhang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao 266021, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao 266021, China; Key Laboratory of Birth Regulation and Control Technology of National Health Commission of China, Maternal and Child Health Care Hospital of Shandong Province affiliated to Qingdao University, Shandong Province, China
| | - Bingqiang Zhang
- Key Laboratory of Cancer and Immune Cells of Qingdao, Qingdao 266021, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao 266021, China.
| | - Yi Zhao
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao 266021, China.
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7
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Nussinov R, Tsai CJ, Jang H. A New View of Activating Mutations in Cancer. Cancer Res 2022; 82:4114-4123. [PMID: 36069825 PMCID: PMC9664134 DOI: 10.1158/0008-5472.can-22-2125] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/16/2022] [Accepted: 09/01/2022] [Indexed: 12/14/2022]
Abstract
A vast effort has been invested in the identification of driver mutations of cancer. However, recent studies and observations call into question whether the activating mutations or the signal strength are the major determinant of tumor development. The data argue that signal strength determines cell fate, not the mutation that initiated it. In addition to activating mutations, factors that can impact signaling strength include (i) homeostatic mechanisms that can block or enhance the signal, (ii) the types and locations of additional mutations, and (iii) the expression levels of specific isoforms of genes and regulators of proteins in the pathway. Because signal levels are largely decided by chromatin structure, they vary across cell types, states, and time windows. A strong activating mutation can be restricted by low expression, whereas a weaker mutation can be strengthened by high expression. Strong signals can be associated with cell proliferation, but too strong a signal may result in oncogene-induced senescence. Beyond cancer, moderate signal strength in embryonic neural cells may be associated with neurodevelopmental disorders, and moderate signals in aging may be associated with neurodegenerative diseases, like Alzheimer's disease. The challenge for improving patient outcomes therefore lies in determining signaling thresholds and predicting signal strength.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, NCI, Frederick, Maryland
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, NCI, Frederick, Maryland
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, NCI, Frederick, Maryland
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8
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Kotzampasi DM, Premeti K, Papafotika A, Syropoulou V, Christoforidis S, Cournia Z, Leondaritis G. The orchestrated signaling by PI3Kα and PTEN at the membrane interface. Comput Struct Biotechnol J 2022; 20:5607-5621. [PMID: 36284707 PMCID: PMC9578963 DOI: 10.1016/j.csbj.2022.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 11/16/2022] Open
Abstract
The oncogene PI3Kα and the tumor suppressor PTEN represent two antagonistic enzymatic activities that regulate the interconversion of the phosphoinositide lipids PI(4,5)P2 and PI(3,4,5)P3 in membranes. As such, they are defining components of phosphoinositide-based cellular signaling and membrane trafficking pathways that regulate cell survival, growth, and proliferation, and are often deregulated in cancer. In this review, we highlight aspects of PI3Kα and PTEN interplay at the intersection of signaling and membrane trafficking. We also discuss the mechanisms of PI3Kα- and PTEN- membrane interaction and catalytic activation, which are fundamental for our understanding of the structural and allosteric implications on signaling at the membrane interface and may aid current efforts in pharmacological targeting of these proteins.
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Affiliation(s)
- Danai Maria Kotzampasi
- Biomedical Research Foundation, Academy of Athens, Athens 11527, Greece
- Department of Biology, University of Crete, Heraklion 71500, Greece
| | - Kyriaki Premeti
- Laboratory of Pharmacology, Faculty of Medicine, University of Ioannina, Ioannina 45110, Greece
| | - Alexandra Papafotika
- Laboratory of Biological Chemistry, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina 45110, Greece
- Biomedical Research Institute, Foundation for Research and Technology, Ioannina 45110, Greece
| | - Vasiliki Syropoulou
- Laboratory of Pharmacology, Faculty of Medicine, University of Ioannina, Ioannina 45110, Greece
| | - Savvas Christoforidis
- Laboratory of Biological Chemistry, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina 45110, Greece
- Biomedical Research Institute, Foundation for Research and Technology, Ioannina 45110, Greece
| | - Zoe Cournia
- Biomedical Research Foundation, Academy of Athens, Athens 11527, Greece
| | - George Leondaritis
- Laboratory of Pharmacology, Faculty of Medicine, University of Ioannina, Ioannina 45110, Greece
- Institute of Biosciences, University Research Center of Ioannina, Ioannina 45110, Greece
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9
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Hall DCN, Benndorf RA. Aspirin sensitivity of PIK3CA-mutated Colorectal Cancer: potential mechanisms revisited. Cell Mol Life Sci 2022; 79:393. [PMID: 35780223 PMCID: PMC9250486 DOI: 10.1007/s00018-022-04430-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/01/2022] [Accepted: 06/14/2022] [Indexed: 11/30/2022]
Abstract
PIK3CA mutations are amongst the most prevalent somatic mutations in cancer and are associated with resistance to first-line treatment along with low survival rates in a variety of malignancies. There is evidence that patients carrying PIK3CA mutations may benefit from treatment with acetylsalicylic acid, commonly known as aspirin, particularly in the setting of colorectal cancer. In this regard, it has been clarified that Class IA Phosphatidylinositol 3-kinases (PI3K), whose catalytic subunit p110α is encoded by the PIK3CA gene, are involved in signal transduction that regulates cell cycle, cell growth, and metabolism and, if disturbed, induces carcinogenic effects. Although PI3K is associated with pro-inflammatory cyclooxygenase-2 (COX-2) expression and signaling, and COX-2 is among the best-studied targets of aspirin, the mechanisms behind this clinically relevant phenomenon are still unclear. Indeed, there is further evidence that the protective, anti-carcinogenic effect of aspirin in this setting may be mediated in a COX-independent manner. However, until now the understanding of aspirin's prostaglandin-independent mode of action is poor. This review will provide an overview of the current literature on this topic and aims to analyze possible mechanisms and targets behind the aspirin sensitivity of PIK3CA-mutated cancers.
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Affiliation(s)
- Daniella C N Hall
- Department of Clinical Pharmacy and Pharmacotherapy, Institute of Pharmacy, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany
| | - Ralf A Benndorf
- Department of Clinical Pharmacy and Pharmacotherapy, Institute of Pharmacy, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany.
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10
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Maloney RC, Zhang M, Liu Y, Jang H, Nussinov R. The mechanism of activation of MEK1 by B-Raf and KSR1. Cell Mol Life Sci 2022; 79:281. [PMID: 35508574 PMCID: PMC9068654 DOI: 10.1007/s00018-022-04296-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/04/2022] [Accepted: 04/07/2022] [Indexed: 12/01/2022]
Abstract
MEK1 interactions with B-Raf and KSR1 are key steps in Ras/Raf/MEK/ERK signaling. Despite this, vital mechanistic details of how these execute signal transduction are still enigmatic. Among these is why, despite B-Raf and KSR1 kinase domains similarity, the B-Raf/MEK1 and KSR1/MEK1 complexes have distinct contributions to MEK1 activation, and broadly, what is KSR1's role. Our molecular dynamics simulations clarify these still unresolved ambiguities. Our results reveal that the proline-rich (P-rich) loop of MEK1 plays a decisive role in MEK1 activation loop (A-loop) phosphorylation. In the inactive B-Raf/MEK1 heterodimer, the collapsed A-loop of B-Raf interacts with the P-rich loop and A-loop of MEK1, minimizing MEK1 A-loop fluctuation and preventing it from phosphorylation. In the active B-Raf/MEK1 heterodimer, the P-rich loop moves in concert with the A-loop of B-Raf as it extends. This reduces the number of residues interacting with MEK1 A-loop, allowing increased A-loop fluctuation, and bringing Ser222 closer to ATP for phosphorylation. B-Raf αG-helix Arg662 promotes MEK1 activation by orienting Ser218 towards ATP. In KSR1/MEK1, the KSR1 αG-helix has Ala826 in place of B-Raf Arg662. This difference results in much fewer interactions between KSR1 αG-helix and MEK1 A-loop, thus a more flexible A-loop. We postulate that if KSR1 were to adopt an active configuration with an extended A-loop as seen in other protein kinases, then the MEK1 P-rich loop would extend in a similar manner, as seen in the active B-Raf/MEK1 heterodimer. This would result in highly flexible MEK1 A-loop, and KSR1 functioning as an active, B-Raf-like, kinase.
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Affiliation(s)
- Ryan C Maloney
- 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
| | - Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute, Frederick, MD, 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA.
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel.
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11
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Abstract
Three-dimensional protein structural data at the molecular level are pivotal for successful precision medicine. Such data are crucial not only for discovering drugs that act to block the active site of the target mutant protein but also for clarifying to the patient and the clinician how the mutations harbored by the patient work. The relative paucity of structural data reflects their cost, challenges in their interpretation, and lack of clinical guidelines for their utilization. Rapid technological advancements in experimental high-resolution structural determination increasingly generate structures. Computationally, modeling algorithms, including molecular dynamics simulations, are becoming more powerful, as are compute-intensive hardware, particularly graphics processing units, overlapping with the inception of the exascale era. Accessible, freely available, and detailed structural and dynamical data can be merged with big data to powerfully transform personalized pharmacology. Here we review protein and emerging genome high-resolution data, along with means, applications, and examples underscoring their usefulness in precision medicine. Expected final online publication date for the Annual Review of Biomedical Data Science, Volume 5 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA; .,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA;
| | - Guy Nir
- Department of Biochemistry and Molecular Biology, Department of Neuroscience, Cell Biology and Anatomy, and Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA;
| | - Feixiong Cheng
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.,Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.,Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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12
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Kulkarni P, Leite VBP, Roy S, Bhattacharyya S, Mohanty A, Achuthan S, Singh D, Appadurai R, Rangarajan G, Weninger K, Orban J, Srivastava A, Jolly MK, Onuchic JN, Uversky VN, Salgia R. Intrinsically disordered proteins: Ensembles at the limits of Anfinsen's dogma. BIOPHYSICS REVIEWS 2022; 3:011306. [PMID: 38505224 PMCID: PMC10903413 DOI: 10.1063/5.0080512] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/17/2022] [Indexed: 03/21/2024]
Abstract
Intrinsically disordered proteins (IDPs) are proteins that lack rigid 3D structure. Hence, they are often misconceived to present a challenge to Anfinsen's dogma. However, IDPs exist as ensembles that sample a quasi-continuum of rapidly interconverting conformations and, as such, may represent proteins at the extreme limit of the Anfinsen postulate. IDPs play important biological roles and are key components of the cellular protein interaction network (PIN). Many IDPs can interconvert between disordered and ordered states as they bind to appropriate partners. Conformational dynamics of IDPs contribute to conformational noise in the cell. Thus, the dysregulation of IDPs contributes to increased noise and "promiscuous" interactions. This leads to PIN rewiring to output an appropriate response underscoring the critical role of IDPs in cellular decision making. Nonetheless, IDPs are not easily tractable experimentally. Furthermore, in the absence of a reference conformation, discerning the energy landscape representation of the weakly funneled IDPs in terms of reaction coordinates is challenging. To understand conformational dynamics in real time and decipher how IDPs recognize multiple binding partners with high specificity, several sophisticated knowledge-based and physics-based in silico sampling techniques have been developed. Here, using specific examples, we highlight recent advances in energy landscape visualization and molecular dynamics simulations to discern conformational dynamics and discuss how the conformational preferences of IDPs modulate their function, especially in phenotypic switching. Finally, we discuss recent progress in identifying small molecules targeting IDPs underscoring the potential therapeutic value of IDPs. Understanding structure and function of IDPs can not only provide new insight on cellular decision making but may also help to refine and extend Anfinsen's structure/function paradigm.
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Affiliation(s)
- Prakash Kulkarni
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Vitor B. P. Leite
- Departamento de Física, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista (UNESP), São José do Rio Preto, São Paulo 15054-000, Brazil
| | - Susmita Roy
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741246, India
| | - Supriyo Bhattacharyya
- Translational Bioinformatics, Center for Informatics, Department of Computational and Quantitative Medicine, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Atish Mohanty
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Srisairam Achuthan
- Center for Informatics, Division of Research Informatics, City of Hope National Medical Center, Duarte, California 91010, USA
| | - Divyoj Singh
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Rajeswari Appadurai
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Govindan Rangarajan
- Department of Mathematics, Indian Institute of Science, Bangalore 560012, India
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
| | | | - Anand Srivastava
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Mohit Kumar Jolly
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Jose N. Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005-1892, USA
| | | | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, California 91010, USA
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13
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Protein Tyrosine Phosphatases: Mechanisms in Cancer. Int J Mol Sci 2021; 22:ijms222312865. [PMID: 34884670 PMCID: PMC8657787 DOI: 10.3390/ijms222312865] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 12/12/2022] Open
Abstract
Protein tyrosine kinases, especially receptor tyrosine kinases, have dominated the cancer therapeutics sphere as proteins that can be inhibited to selectively target cancer. However, protein tyrosine phosphatases (PTPs) are also an emerging target. Though historically known as negative regulators of the oncogenic tyrosine kinases, PTPs are now known to be both tumor-suppressive and oncogenic. This review will highlight key protein tyrosine phosphatases that have been thoroughly investigated in various cancers. Furthermore, the different mechanisms underlying pro-cancerous and anti-cancerous PTPs will also be explored.
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14
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Nussinov R, Zhang M, Maloney R, Tsai CJ, Yavuz BR, Tuncbag N, Jang H. Mechanism of activation and the rewired network: New drug design concepts. Med Res Rev 2021; 42:770-799. [PMID: 34693559 PMCID: PMC8837674 DOI: 10.1002/med.21863] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/06/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022]
Abstract
Precision oncology benefits from effective early phase drug discovery decisions. Recently, drugging inactive protein conformations has shown impressive successes, raising the cardinal questions of which targets can profit and what are the principles of the active/inactive protein pharmacology. Cancer driver mutations have been established to mimic the protein activation mechanism. We suggest that the decision whether to target an inactive (or active) conformation should largely rest on the protein mechanism of activation. We next discuss the recent identification of double (multiple) same-allele driver mutations and their impact on cell proliferation and suggest that like single driver mutations, double drivers also mimic the mechanism of activation. We further suggest that the structural perturbations of double (multiple) in cis mutations may reveal new surfaces/pockets for drug design. Finally, we underscore the preeminent role of the cellular network which is deregulated in cancer. Our structure-based review and outlook updates the traditional Mechanism of Action, informs decisions, and calls attention to the intrinsic activation mechanism of the target protein and the rewired tumor-specific network, ushering innovative considerations in precision medicine.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA
| | - Ryan Maloney
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA
| | - Bengi Ruken Yavuz
- Department of Health Informatics, Graduate School of Informatics, Middle East Technical University, Ankara, Turkey
| | - Nurcan Tuncbag
- Department of Health Informatics, Graduate School of Informatics, Middle East Technical University, Ankara, Turkey.,Department of Chemical and Biological Engineering, College of Engineering, Koc University, Istanbul, Turkey.,Koc University Research Center for Translational Medicine, School of Medicine, Koc University, Istanbul, Turkey
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland, USA
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15
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Chen Y, Zheng YF, Lin XH, Zhang JP, Lin F, Shi H. Dendrobium mixture attenuates renal damage in rats with diabetic nephropathy by inhibiting the PI3K/Akt/mTOR pathway. Mol Med Rep 2021; 24:590. [PMID: 34165163 PMCID: PMC8222963 DOI: 10.3892/mmr.2021.12229] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/18/2021] [Indexed: 11/06/2022] Open
Abstract
Dendrobium mixture (DMix) is a Traditional Chinese Medicine widely used for preventing and treating diabetic nephropathy (DN). Autophagy contributes to DN development and progression. The present study aimed to investigate the mechanism underlying the protective effects of DMix on the kidneys of rats with DN and to determine whether this involves autophagy. Herein, a high‑sugar and high‑fat diet, combined with the intra‑abdominal injection of low‑dose streptozocin, was used to induce DN in 40 Sprague‑Dawley male rats. In total, 10 additional rats were used as controls. The rats with DN were then randomly divided into three groups and treated with DMix, gliquidone or saline via gastric administration for 8 weeks. Body weight, kidney weight, kidney index, fasting blood glucose (FBG), blood lipid, hemoglobin A1c (HbA1c), insulin, blood urea nitrogen and serum creatinine levels, as well as the 24‑h urinary albumin excretion rate (UAER) were measured. H&E, Periodic Acid‑Schiff and Masson staining were used to examine the renal pathology. The mRNA and protein expression levels of LC3 and Beclin‑1 in renal tissues were measured using reverse transcription‑quantitative PCR and immunohistochemistry, respectively. Western blotting was conducted to measure the protein expression levels of PI3K, phosphorylated (p)‑PI3K, Akt, p‑Akt, mTOR, p‑mTOR, LC3 and Beclin‑1 in renal tissues. It was found that DMix significantly reduced the FBG, blood lipids, HbA1c and insulin levels, kidney weight, kidney index and UAER in rats with DN, as well as improved renal function. Rats with DN showed notable glomerular hypertrophy, an increase in mesangial matrix content and renal interstitial fibrosis. Moreover, DMix notably reduced kidney damage. The results demonstrated that DMix inhibited the phosphorylation of PI3K, Akt and mTOR in the kidney tissues of rats with DN, and increased the protein and mRNA expression levels of LC3 and Beclin‑1. Therefore, it was suggested that DMix has protective effects on the kidney of rats with DN, which may be associated with the inhibition of the PI3K/Akt/mTOR signaling pathway and activation of renal autophagy by this traditional medicine.
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Affiliation(s)
- Yong Chen
- School of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China
| | - Yan Fang Zheng
- School of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China
| | - Xiao Hui Lin
- School of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China
| | - Jie Ping Zhang
- School of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China
| | - Fan Lin
- School of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China
| | - Hong Shi
- School of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, P.R. China
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16
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Novel MAPK/AKT-impairing germline NRAS variant identified in a melanoma-prone family. Fam Cancer 2021; 21:347-355. [PMID: 34215961 DOI: 10.1007/s10689-021-00267-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/12/2021] [Indexed: 12/24/2022]
Abstract
While several high-penetrance melanoma risk genes are known, variation in these genes fail to explain melanoma susceptibility in a large proportion of high-risk families. As part of a melanoma family sequencing study, including 435 families from Mediterranean populations we identified a novel NRAS variant (c.170A > C, p.D57A) in an Italian melanoma-prone family. This variant is absent in exomes in gnomAD, ESP, UKBiobank, and the 1000 Genomes Project, as well as in 11,273 Mediterranean individuals and 109 melanoma-prone families from the US and Australia. This variant occurs in the GTP-binding pocket of NRAS. Differently from other RAS activating alterations, NRAS D57A expression is unable to activate MAPK-pathway both constitutively and after stimulation but enhances EGF-induced PI3K-pathway signaling in serum starved conditions in vitro. Consistent with in vitro data demonstrating that NRAS D57A does not enrich GTP binding, molecular modeling suggests that the D57A substitution would be expected to impair Mg2 + binding and decrease nucleotide-binding and GTPase activity of NRAS. While we cannot firmly establish NRAS c.170A > C (p.D57A) as a melanoma susceptibility variant, further investigation of NRAS as a familial melanoma gene is warranted.
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17
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Maloney RC, Zhang M, Jang H, Nussinov R. The mechanism of activation of monomeric B-Raf V600E. Comput Struct Biotechnol J 2021; 19:3349-3363. [PMID: 34188782 PMCID: PMC8215184 DOI: 10.1016/j.csbj.2021.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/30/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
Oncogenic mutations in the serine/threonine kinase B-Raf, particularly the V600E mutation, are frequent in cancer, making it a major drug target. Although much is known about B-Raf's active and inactive states, questions remain about the mechanism by which the protein changes between these two states. Here, we utilize molecular dynamics to investigate both wild-type and V600E B-Raf to gain mechanistic insights into the impact of the Val to Glu mutation. The results show that the wild-type and mutant follow similar activation pathways involving an extension of the activation loop and an inward motion of the αC-helix. The V600E mutation, however, destabilizes the inactive state by disrupting hydrophobic interactions present in the wild-type structure while the active state is stabilized through the formation of a salt bridge between Glu600 and Lys507. Additionally, when the activation loop is extended, the αC-helix is able to move between an inward and outward orientation as long as the DFG motif adopts a specific orientation. In that orientation Phe595 rotates away from the αC-helix, allowing the formation of a salt bridge between Lys483 and Glu501. These mechanistic insights have implications for the development of new Raf inhibitors.
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Affiliation(s)
- Ryan C. Maloney
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
- Corresponding author at: Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA.
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18
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Weako J, Jang H, Keskin O, Nussinov R, Gursoy A. The structural basis of Akt PH domain interaction with calmodulin. Biophys J 2021; 120:1994-2008. [PMID: 33775637 PMCID: PMC8204387 DOI: 10.1016/j.bpj.2021.03.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 03/10/2021] [Accepted: 03/18/2021] [Indexed: 11/17/2022] Open
Abstract
Akt plays a key role in the Ras/PI3K/Akt/mTOR signaling pathway. In breast cancer, Akt translocation to the plasma membrane is enabled by the interaction of its pleckstrin homology domain (PHD) with calmodulin (CaM). At the membrane, the conformational change promoted by PIP3 releases CaM and facilitates Thr308 and Ser473 phosphorylation and activation. Here, using modeling and molecular dynamics simulations, we aim to figure out how CaM interacts with Akt's PHD at the atomic level. Our simulations show that CaM-PHD interaction is thermodynamically stable and involves a β-strand rather than an α-helix, in agreement with NMR data, and that electrostatic and hydrophobic interactions are critical. The PHD interacts with CaM lobes; however, multiple modes are possible. IP4, the polar head of PIP3, weakens the CaM-PHD interaction, implicating the release mechanism at the plasma membrane. Recently, we unraveled the mechanism of PI3Kα activation at the atomistic level and the structural basis for Ras role in the activation. Here, our atomistic structural data clarify the mechanism of how CaM interacts, delivers, and releases Akt-the next node in the Ras/PI3K pathway-at the plasma membrane.
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Affiliation(s)
- Jackson Weako
- Computational Science and Engineering Program, Koç University, Istanbul, Turkey
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koç University, Istanbul, Turkey
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Attila Gursoy
- Department of Computer Engineering, Koç University, Istanbul, Turkey.
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19
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Tian W, Liu X, Wang L, Zheng B, Jiang K, Fu G, Feng W. Deciphering the selective binding mechanisms of anaplastic lymphoma kinase-derived neuroblastoma tumor neoepitopes to human leukocyte antigen. J Mol Model 2021; 27:134. [PMID: 33899124 DOI: 10.1007/s00894-021-04754-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 04/15/2021] [Indexed: 12/14/2022]
Abstract
Neuroblastoma (NB), as a metastatic form of solid tumor, has a high fatality rate found in early childhood. The two anaplastic lymphoma kinase (ALK) neoepitopes nonamer and decamer used in cancer immunotherapy against NB cancer can selectively bind to the human leukocyte antigen (HLA-B*15:01) groove with high affinities, whereas the native self-peptide is unable to interact with the HLA-B*15:01. Here, we performed molecular dynamics (MD) simulations and subsequent molecular mechanics-generalized born surface area (MM-GBSA) binding free energy calculations to explore the selective binding mechanisms of nonamer and decamer to the HLA-B*15:01 against the self-peptide. MD simulations revealed the significant conformational dynamics of the self-peptide in the HLA-B*15:01 groove against the nonamer and decamer. Binding free energy calculations showed that the binding affinities of HLA-B*15:01-neoepitope complexes were followed in the order decamer > nonamer > self-peptide. Detailed analysis of HLA-B*15:01-neoepitope structural complexes showed that compared to the nonamer, the self-peptide tended to move outward to the solvent, whereas the decamer moved deep to the HLA-B*15:01 groove. These different dynamic observations of the ALK neoepitopes can explain the distinct binding affinities of self-peptide, nonamer, and decamer to the HLA-B*15:01. The results may be useful for the design of more selective ALK neoepitopes.
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Affiliation(s)
- Wenchao Tian
- Pediatric Surgery, Binzhou Medical University Hospital, Binzhou, 256603, Shandong, China
| | - Xianxian Liu
- Department of Infectious Diseases, Binzhou Medical University Hospital, Binzhou, 256603, Shandong, China
| | - Lulu Wang
- Department of Critical Care Medicine, Binzhou Medical University Hospital, Binzhou, 256603, Shandong, China
| | - Bufeng Zheng
- Pediatric Surgery, Binzhou Medical University Hospital, Binzhou, 256603, Shandong, China
| | - Kun Jiang
- Pediatric Surgery, Binzhou Medical University Hospital, Binzhou, 256603, Shandong, China
| | - Guoyong Fu
- Pediatric Surgery, Binzhou Medical University Hospital, Binzhou, 256603, Shandong, China
| | - Wenyu Feng
- Pediatric Surgery, Binzhou Medical University Hospital, Binzhou, 256603, Shandong, China.
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20
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Jang H, Smith IN, Eng C, Nussinov R. The mechanism of full activation of tumor suppressor PTEN at the phosphoinositide-enriched membrane. iScience 2021; 24:102438. [PMID: 34113810 PMCID: PMC8169795 DOI: 10.1016/j.isci.2021.102438] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/15/2021] [Accepted: 04/12/2021] [Indexed: 12/13/2022] Open
Abstract
Tumor suppressor PTEN, the second most highly mutated protein in cancer, dephosphorylates signaling lipid PIP3 produced by PI3Ks. Excess PIP3 promotes cell proliferation. The mechanism at the membrane of this pivotal phosphatase is unknown hindering drug discovery. Exploiting explicit solvent simulations, we tracked full-length PTEN trafficking from the cytosol to the membrane. We observed its interaction with membranes composed of zwitterionic phosphatidylcholine, anionic phosphatidylserine, and phosphoinositides, including signaling lipids PIP2 and PIP3. We tracked its moving away from the zwitterionic and getting absorbed onto anionic membrane that harbors PIP3. We followed it localizing on microdomains enriched in signaling lipids, as PI3K does, and observed PIP3 allosterically unfolding the N-terminal PIP2 binding domain, positioning it favorably for the polybasic motif interaction with PIP2. Finally, we determined PTEN catalytic action at the membrane, all in line with experimental observations, deciphering the mechanisms of how PTEN anchors to the membrane and restrains cancer. PTEN localizes on membrane microdomains enriched in phosphoinositides, as PI3K does Full PTEN activation requires both signaling lipids, PIP2 and PIP3 Strong salt bridge interactions sustain stable PTEN membrane localization Substrate-induced P loop conformational change implicates PTEN catalytic activity
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Affiliation(s)
- Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Iris Nira Smith
- Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA
| | - Charis Eng
- Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA.,Center for Personalized Genetic Healthcare, Cleveland Clinic Community Care and Population Health, Cleveland, OH 44195, USA.,Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.,Germline High Risk Cancer Focus Group, Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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21
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Martinez NG, Thieker DF, Carey LM, Rasquinha JA, Kistler SK, Kuhlman BA, Campbell SL. Biophysical and Structural Characterization of Novel RAS-Binding Domains (RBDs) of PI3Kα and PI3Kγ. J Mol Biol 2021; 433:166838. [PMID: 33539876 PMCID: PMC8005443 DOI: 10.1016/j.jmb.2021.166838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/26/2020] [Accepted: 01/18/2021] [Indexed: 12/15/2022]
Abstract
Phosphatidylinositol-3-kinases (PI3Ks) are lipid kinases that phosphorylate phosphatidylinositol 4,5-bisphosphate to generate a key lipid second messenger, phosphatidylinositol 3,4,5-bisphosphate. PI3Kα and PI3Kγ require activation by RAS proteins to stimulate signaling pathways that control cellular growth, differentiation, motility and survival. Intriguingly, RAS binding to PI3K isoforms likely differ, as RAS mutations have been identified that discriminate between PI3Kα and PI3Kγ, consistent with low sequence homology (23%) between their RAS binding domains (RBDs). As disruption of the RAS/PI3Kα interaction reduces tumor growth in mice with RAS- and epidermal growth factor receptor driven skin and lung cancers, compounds that interfere with this key interaction may prove useful as anti-cancer agents. However, a structure of PI3Kα bound to RAS is lacking, limiting drug discovery efforts. Expression of full-length PI3K isoforms in insect cells has resulted in low yield and variable activity, limiting biophysical and structural studies of RAS/PI3K interactions. This led us to generate the first RBDs from PI3Kα and PI3Kγ that can be expressed at high yield in bacteria and bind to RAS with similar affinity to full-length PI3K. We also solved a 2.31 Å X-ray crystal structure of the PI3Kα-RBD, which aligns well to full-length PI3Kα. Structural differences between the PI3Kα and PI3Kγ RBDs are consistent with differences in thermal stability and may underly differential RAS recognition and RAS-mediated PI3K activation. These high expression, functional PI3K RBDs will aid in interrogating RAS interactions and could aid in identifying inhibitors of this key interaction.
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Affiliation(s)
- Nicholas G Martinez
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, United States
| | - David F Thieker
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, United States; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, United States
| | - Leiah M Carey
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, United States; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, United States
| | - Juhi A Rasquinha
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, United States
| | - Samantha K Kistler
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, United States
| | - Brian A Kuhlman
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, United States; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, United States
| | - Sharon L Campbell
- Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, United States; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, United States.
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22
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Nussinov R, Jang H, Gursoy A, Keskin O, Gaponenko V. Inhibition of Nonfunctional Ras. Cell Chem Biol 2021; 28:121-133. [PMID: 33440168 PMCID: PMC7897307 DOI: 10.1016/j.chembiol.2020.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/28/2020] [Accepted: 12/21/2020] [Indexed: 02/07/2023]
Abstract
Intuitively, functional states should be targeted; not nonfunctional ones. So why could drugging the inactive K-Ras4BG12Cwork-but drugging the inactive kinase will likely not? The reason is the distinct oncogenic mechanisms. Kinase driver mutations work by stabilizing the active state and/or destabilizing the inactive state. Either way, oncogenic kinases are mostly in the active state. Ras driver mutations work by quelling its deactivation mechanisms, GTP hydrolysis, and nucleotide exchange. Covalent inhibitors that bind to the inactive GDP-bound K-Ras4BG12C conformation can thus work. By contrast, in kinases, allosteric inhibitors work by altering the active-site conformation to favor orthosteric drugs. From the translational standpoint this distinction is vital: it expedites effective pharmaceutical development and extends the drug classification based on the mechanism of action. Collectively, here we postulate that drug action relates to blocking the mechanism of activation, not to whether the protein is in the active or inactive state.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Attila Gursoy
- Department of Computer Engineering, Koc University, Istanbul 34450, Turkey
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koc University, Istanbul 34450, Turkey
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.
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Zhang M, Jang H, Nussinov R. PI3K Driver Mutations: A Biophysical Membrane-Centric Perspective. Cancer Res 2021; 81:237-247. [PMID: 33046444 PMCID: PMC7855922 DOI: 10.1158/0008-5472.can-20-0911] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/24/2020] [Accepted: 10/07/2020] [Indexed: 11/16/2022]
Abstract
Ras activates its effectors at the membrane. Active PI3Kα and its associated kinases/phosphatases assemble at membrane regions enriched in signaling lipids. In contrast, the Raf kinase domain extends into the cytoplasm and its assembly is away from the crowded membrane surface. Our structural membrane-centric outlook underscores the spatiotemporal principles of membrane and signaling lipids, which helps clarify PI3Kα activation. Here we focus on mechanisms of activation driven by PI3Kα driver mutations, spotlighting the PI3Kα double (multiple) activating mutations. Single mutations can be potent, but double mutations are stronger: their combination is specific, a single strong driver cannot fully activate PI3K, and two weak drivers may or may not do so. In contrast, two strong drivers may successfully activate PI3K, where one, for example, H1047R, modulates membrane interactions facilitating substrate binding at the active site (km) and the other, for example, E542K and E545K, reduces the transition state barrier (ka), releasing autoinhibition by nSH2. Although mostly unidentified, weak drivers are expected to be common, so we ask here how common double mutations are likely to be and why PI3Kα with double mutations responds effectively to inhibitors. We provide a structural view of hotspot and weak driver mutations in PI3Kα activation, explain their mechanisms, compare these with mechanisms of Raf activation, and point to targeting cell-specific, chromatin-accessible, and parallel (or redundant) pathways to thwart the expected emergence of drug resistance. Collectively, our biophysical outlook delineates activation and highlights the challenges of drug resistance.
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Affiliation(s)
- Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland.
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Nussinov R, Zhang M, Tsai CJ, Jang H. Phosphorylation and Driver Mutations in PI3Kα and PTEN Autoinhibition. Mol Cancer Res 2020; 19:543-548. [PMID: 33288731 DOI: 10.1158/1541-7786.mcr-20-0818] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/29/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022]
Abstract
PI3K and PTEN are the second and third most highly mutated proteins in cancer following only p53. Their actions oppose each other. PI3K phosphorylates signaling lipid PIP2 to PIP3 PTEN dephosphorylates it back. Driver mutations in both proteins accrue PIP3 PIP3 recruits AKT and PDK1 to the membrane, promoting cell-cycle progression. Here we review phosphorylation events and mutations in autoinhibition in PI3K and PTEN from the structural standpoint. Our purpose is to clarify how they control the autoinhibited states. In autoinhibition, a segment or a subunit of the protein occludes its functional site. Protein-protein interfaces are often only marginally stable, making them sensitive to changes in conditions in living cells. Phosphorylation can stabilize or destabilize the interfaces. Driver mutations commonly destabilize them. In analogy to "passenger mutations," we coin "passenger phosphorylation" to emphasize that the presence of a phosphorylation recognition sequence logo does not necessarily imply function. Rather, it may simply reflect a statistical occurrence. In both PI3K and PTEN, autoinhibiting phosphorylation events are observed in the occluding "piece." In PI3Kα, the "piece" is the p85α subunit. In PTEN, it is the C-terminal segment. In both enzymes the stabilized interface covers the domain that attaches to the membrane. Driver mutations that trigger rotation of the occluding piece or its deletion prompt activation. To date, both enzymes lack specific, potent drugs. We discuss the implications of detailed structural and mechanistic insight into oncogenic activation and how it can advance allosteric precision oncology.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, NCI, Frederick, Maryland. .,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, NCI, Frederick, Maryland
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, NCI, Frederick, Maryland
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, NCI, Frederick, Maryland
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25
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Abstract
The genetic alterations in cancer cells are tightly linked to signaling pathway dysregulation. Ras is a key molecule that controls several tumorigenesis-related processes, and mutations in RAS genes often lead to unbiased intensification of signaling networks that fuel cancer progression. In this article, we review recent studies that describe mutant Ras-regulated signaling routes and their cross-talk. In addition to the two main Ras-driven signaling pathways, i.e., the RAF/MEK/ERK and PI3K/AKT/mTOR pathways, we have also collected emerging data showing the importance of Ras in other signaling pathways, including the RAC/PAK, RalGDS/Ral, and PKC/PLC signaling pathways. Moreover, microRNA-regulated Ras-associated signaling pathways are also discussed to highlight the importance of Ras regulation in cancer. Finally, emerging data show that the signal alterations in specific cell types, such as cancer stem cells, could promote cancer development. Therefore, we also cover the up-to-date findings related to Ras-regulated signal transduction in cancer stem cells.
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Affiliation(s)
- Tamás Takács
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Gyöngyi Kudlik
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Anita Kurilla
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Bálint Szeder
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
| | - László Buday
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary
- Department of Medical Chemistry, Semmelweis University Medical School, Budapest, Hungary
| | - Virag Vas
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Hungary.
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26
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Zhang M, Jang H, Nussinov R. Structural Features that Distinguish Inactive and Active PI3K Lipid Kinases. J Mol Biol 2020; 432:5849-5859. [PMID: 32918948 PMCID: PMC8916166 DOI: 10.1016/j.jmb.2020.09.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/10/2020] [Accepted: 09/02/2020] [Indexed: 12/25/2022]
Abstract
PI3K lipid kinases signal through the PI3K/Akt pathway, regulating cell growth and proliferation. While the structural features that distinguish between the active and inactive states of protein kinases are well established, that has not been the case for lipid kinases, and neither was the structural mechanism controlling the switch between the two states. Class I PI3Ks are obligate heterodimers with catalytic and regulatory subunits. Here, we analyze PI3K crystal structures. Structures with the nSH2 (inactive state) are featured by collapsed activation loop (a-loop) and an IN kinase domain helix 11 (kα11). In the active state, the a-loop is extended and kα11 in the OUT conformation. Our analysis suggests that the nSH2 domain in the regulatory subunit regulates activation, catalysis and autoinhibition through the a-loop. Inhibition, activation and catalytic scenarios are shared by class IA PI3Ks; the activation is mimicked by oncogenic mutations and the inhibition offers an allosteric inhibitor strategy.
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Affiliation(s)
- Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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Study of Ras Mutations' Prognostic Value in Metastatic Colorectal Cancer: STORIA Analysis. Cancers (Basel) 2020; 12:cancers12071919. [PMID: 32708575 PMCID: PMC7409181 DOI: 10.3390/cancers12071919] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/06/2020] [Accepted: 07/13/2020] [Indexed: 12/16/2022] Open
Abstract
Background: Colorectal cancer (CRC) is the second most common cause of cancer-specific death in both sexes in Western countries. KRAS mutations occur in about 50% of metastatic CRCs (mCRCs). The prognostic value of specific KRAS mutations still remains unexplored and unclear. Methods: Two hundred and forty KRAS wild-type and 206 KRAS/NRAS mutant consecutive unresectable mCRC patients with PS Eastern Cooperative Oncology Group (ECOG) 0 or 1, aged < 80 years, and with a life expectancy >3 months entered into this study. DNA was extracted from paraffin-embedded formalin-fixed tumour tissues, and it was sequenced with the Oncomine Solid Tumour DNA kit (Thermo Fisher Scientific, Waltham, MA, USA). Data were analysed using the Torrent Suite Software v5.0 (Thermo Fisher Scientific). The primary outcome was the analysis of the prognostic role of different KRAS mutations in terms of overall survival (OS). Results: There were no significant differences among the most prevalent mutations (p.G12D, p.G12V, p.G13D, p.G12A, p.G12C, and p.G12S) in terms of age (<65 vs. ≥65 years), gender (male vs. female), grading (G1/G2 vs. G3), side of primary tumour (left vs. right), pT, and pN. At the median follow-up of 25.6 months, there were 77 deaths in KRAS-mutated patients and 94 in wild-type patients. Three homogeneous prognostic groups were identified: wild-type patients (group A, median survival: 27.5 months), p.G13D/p.G12A/p.G12V/p.G12D mutants (group B, median survival: 17.3 months), and p.G12C/p.G12S mutants (group C, median survival: 5.0 months, p < 0.0001 according to Log Rank test). Upon multivariate analysis, metastatic involvement and p.G12C/p.G12S KRAS mutation group C (vs. other mutations) emerged as independent prognostic variables for survival. Conclusions: We show that mutant KRAS is a negative prognostic factor and that p.G12C/p.G12S variants present the worst clinical courses. This information suggests a clear difference among KRAS mutations, and it will be useful to test potentiated and/or innovative therapeutic strategies in p.G12C/p.G12S metastatic CRC patients.
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Zhang M, Jang H, Nussinov R. PI3K inhibitors: review and new strategies. Chem Sci 2020; 11:5855-5865. [PMID: 32953006 PMCID: PMC7472334 DOI: 10.1039/d0sc01676d] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/18/2020] [Indexed: 12/16/2022] Open
Abstract
The search is on for effective specific inhibitors for PI3Kα mutants. PI3Kα, a critical lipid kinase, has two subunits, catalytic and inhibitory. PIK3CA, the gene that encodes the p110α catalytic subunit is a highly mutated protein in cancer. Dysregulation of PI3Kα signalling is commonly associated with tumorigenesis and drug resistance. Despite its vast importance, only recently the FDA approved the first drug (alpelisib by Novartis) for breast cancer. A second (GDC0077), classified as PI3Kα isoform-specific, is undergoing clinical trials. Not surprisingly, these ATP-competitive drugs commonly elicit severe concentration-dependent side effects. Here we briefly review PI3Kα mutations, focus on PI3K drug repertoire and propose new, to-date unexplored PI3Kα therapeutic strategies. These include (1) an allosteric and orthosteric inhibitor combination and (2) taking advantage of allosteric rescue mutations to guide drug discovery.
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Affiliation(s)
- Mingzhen Zhang
- Computational Structural Biology Section , Frederick National Laboratory for Cancer Research , National Cancer Institute at Frederick , Frederick , MD 21702 , USA . ; Tel: +1-301-846-5579
| | - Hyunbum Jang
- Computational Structural Biology Section , Frederick National Laboratory for Cancer Research , National Cancer Institute at Frederick , Frederick , MD 21702 , USA . ; Tel: +1-301-846-5579
| | - Ruth Nussinov
- Computational Structural Biology Section , Frederick National Laboratory for Cancer Research , National Cancer Institute at Frederick , Frederick , MD 21702 , USA . ; Tel: +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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29
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Ras assemblies and signaling at the membrane. Curr Opin Struct Biol 2020; 62:140-148. [DOI: 10.1016/j.sbi.2020.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/16/2020] [Indexed: 02/07/2023]
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30
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Nussinov R, Jang H, Zhang M, Tsai CJ, Sablina AA. The Mystery of Rap1 Suppression of Oncogenic Ras. Trends Cancer 2020; 6:369-379. [PMID: 32249186 PMCID: PMC7211489 DOI: 10.1016/j.trecan.2020.02.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 01/30/2020] [Accepted: 02/03/2020] [Indexed: 12/11/2022]
Abstract
Decades ago, Rap1, a small GTPase very similar to Ras, was observed to suppress oncogenic Ras phenotype, reverting its transformation. The proposed reason, persisting since, has been competition between Ras and Rap1 for a common target. Yet, none was found. There was also Rap1's puzzling suppression of Raf-1 versus activation of BRAF. Reemerging interest in Rap1 envisages capturing its Ras suppression action by inhibitors. Here, we review the literature and resolve the enigma. In vivo oncogenic Ras exists in isoform-distinct nanoclusters. The presence of Rap1 within the nanoclusters reduces the number of the clustered oncogenic Ras molecules, thus suppressing Raf-1 activation and mitogen-activated protein kinase (MAPK) signaling. Nanoclustering suggests that Rap1 suppression is Ras isoform dependent. Altogether, a potent Rap1-like inhibitor appears unlikely.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Anna A Sablina
- VIB Center for the Biology of Disease and KU Leuven Department of Oncology, Leuven Cancer Institute, Leuven, Belgium
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31
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Jang H, Zhang M, Nussinov R. The quaternary assembly of KRas4B with Raf-1 at the membrane. Comput Struct Biotechnol J 2020; 18:737-748. [PMID: 32257057 PMCID: PMC7125320 DOI: 10.1016/j.csbj.2020.03.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/17/2020] [Accepted: 03/19/2020] [Indexed: 02/07/2023] Open
Abstract
Proximally located in the membrane, oncogenic Ras dimers (or nanoclusters) can recruit and promote Raf dimerization and MAPK (Raf/MEK/ERK) signaling. Among Ras isoforms, KRas4B is the most frequently mutated. Recent data on the binary KRas4B–Raf-1 complex suggested that Raf-1 CRD not only executes membrane anchorage, but also supports the high-affinity interaction of Raf-1 RBD with KRas4B catalytic domain. For a detailed mechanistic picture of Raf activation at the membrane, we employ explicit MD simulations of the quaternary KRas4B–Raf-1 complex. The complex contains two active GTP-bound KRas4B proteins forming a dimer through the allosteric lobe interface and two tandem RBD-CRD segments of Raf-1 interacting with the effector lobes at both ends of the KRas4B dimer. We show that Raf-1 RBD-CRD supports stable KRas4B dimer at preferred interface and orientation at the membrane, thereby cooperatively enhancing the affinity of the KRas4B–Raf-1 interaction. We propose that a Ras dimer at the membrane can increase the population of proximal Raf kinase domains, promoting kinase domain dimerization in the cytoplasm. Collectively, the dynamic Ras–Raf assembly promotes Raf activation not by allostery; instead, Ras activates Raf by shifting its ensemble toward kinase domain-accessible states through enhanced affinity at the membrane.
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Affiliation(s)
- Hyunbum Jang
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Mingzhen Zhang
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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32
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Pantsar T. The current understanding of KRAS protein structure and dynamics. Comput Struct Biotechnol J 2019; 18:189-198. [PMID: 31988705 PMCID: PMC6965201 DOI: 10.1016/j.csbj.2019.12.004] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/06/2019] [Accepted: 12/07/2019] [Indexed: 01/10/2023] Open
Abstract
One of the most common drivers in human cancer is the mutant KRAS protein. Not so long ago KRAS was considered as an undruggable oncoprotein. After a long struggle, however, we finally see some light at the end of the tunnel as promising KRAS targeted therapies are in or approaching clinical trials. In recent years, together with the promising progress in RAS drug discovery, our understanding of KRAS has increased tremendously. This progress has been accompanied with a resurgence of publicly available KRAS structures, which were limited to nine structures less than ten years ago. Furthermore, the ever-increasing computational capacity has made biologically relevant timescales accessible, enabling molecular dynamics (MD) simulations to study the dynamics of KRAS protein in more detail at the atomistic level. In this minireview, my aim is to provide the reader an overview of the publicly available KRAS structural data, insights to conformational dynamics revealed by experiments and what we have learned from MD simulations. Also, I will discuss limitations of the current data and provide suggestions for future research related to KRAS, which would fill out the existing gaps in our knowledge and provide guidance in deciphering this enigmatic oncoprotein.
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Affiliation(s)
- Tatu Pantsar
- Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmaceutical Sciences, Eberhard Karls University Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1, 70210 Kuopio, Finland
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33
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Li X, Dai J, Ni D, He X, Zhang H, Zhang J, Fu Q, Liu Y, Lu S. Insight into the mechanism of allosteric activation of PI3Kα by oncoprotein K-Ras4B. Int J Biol Macromol 2019; 144:643-655. [PMID: 31816384 DOI: 10.1016/j.ijbiomac.2019.12.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/02/2019] [Accepted: 12/03/2019] [Indexed: 12/16/2022]
Abstract
Ras is a key member in the superfamily of small GTPase. Transforming between GTP-bound active state and GDP-bound inactive state in response to exogenous signals, Ras serves as a binary switch in various signaling pathways. One of its downstream effectors is phosphatidylinositol-4,5-bisphosphate 3-kinase α (PI3Kα), which phosphorylates phosphatidylinositol 4,5-bisphosphate into phosphatidylinositol 3,4,5-trisphosphate in the PI3K/Akt/mTOR pathway and mediates an array of important cellular activities including cell growth, migration and survival. Hyperactivation of PI3Kα induced by the Ras isoform K-Ras4B has been unveiled as a key event during the oncogenesis of pancreatic ductal adenocarcinoma, but the underlying mechanism of how K-Ras4B allosterically activates PI3Kα still remains largely unsolved. Here, we employed accelerated molecular dynamic simulations and allosteric pathway analysis to explore into the activation process of PI3Kα by K-Ras4B and unraveled the underlying structural mechanisms. We found that K-Ras4B binding induced more conformational dynamics within PI3Kα and triggered its step-wise transition from a self-inhibited state towards an activated state. Moreover, K-Ras4B binding markedly disrupted the interactions along the p110/p85 interface, especially the ones between nSH2 in p85 and its nearby functional domains in p110 like C2, helical, and kinase domains. The altered inter-domain interactions exposed the kinase domain, which promoted the membrane association and substrate phosphorylation of PI3Kα, thereby facilitating its activation. In particular, the community networks and allosteric pathways analysis further revealed that in PI3Kα/K-Ras4B system, allosteric signaling regulating p110/p85 interaction was rewired from the helical domain to the kinase domain and several important residues and their related allosteric pathways mediating PI3Kα autoinhibition were bypassed. The obtained structural mechanisms provide an in-depth mechanistic insight into the allosteric activation of PI3Kα by K-Ras4B as well as shed light on its drug discovery.
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Affiliation(s)
- Xinyi Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Jinyuan Dai
- Chemical Engineering and Technology, School of Chemical Engineering, East China University of Science and Technology, Shanghai 201424, China
| | - Duan Ni
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Xinheng He
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Hao Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Qiang Fu
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China.
| | - Yaqin Liu
- Medicinal Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China.
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China; Medicinal Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China.
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34
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Li J, Wu G, Fu Q, Ge H, Liu S, Li X, Cheng B. Exploring the influence of conserved lysine69 on the catalytic activity of the helicobacter pylori shikimate dehydrogenase: A combined QM/MM and MD simulations. Comput Biol Chem 2019; 83:107098. [DOI: 10.1016/j.compbiolchem.2019.107098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/22/2019] [Accepted: 08/04/2019] [Indexed: 12/29/2022]
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35
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Nussinov R, Tsai C, Jang H. Autoinhibition can identify rare driver mutations and advise pharmacology. FASEB J 2019; 34:16-29. [DOI: 10.1096/fj.201901341r] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/18/2019] [Accepted: 10/09/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section Basic Science Program Frederick National Laboratory for Cancer Research Frederick MD USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Chung‐Jung Tsai
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Hyunbum Jang
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine Tel Aviv University Tel Aviv Israel
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36
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Nussinov R, Tsai CJ, Jang H. Does Ras Activate Raf and PI3K Allosterically? Front Oncol 2019; 9:1231. [PMID: 31799192 PMCID: PMC6874141 DOI: 10.3389/fonc.2019.01231] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/28/2019] [Indexed: 12/11/2022] Open
Abstract
The mechanism through which oncogenic Ras activates its effectors is vastly important to resolve. If allostery is at play, then targeting allosteric pathways could help in quelling activation of MAPK (Raf/MEK/ERK) and PI3K (PI3K/Akt/mTOR) cell proliferation pathways. On the face of it, allosteric activation is reasonable: Ras binding perturbs the conformational ensembles of its effectors. Here, however, we suggest that at least for Raf, PI3K, and NORE1A (RASSF5), that is unlikely. Raf's long disordered linker dampens effective allosteric activation. Instead, we suggest that the high-affinity Ras–Raf binding relieves Raf's autoinhibition, shifting Raf's ensemble from the inactive to the nanocluster-mediated dimerized active state, as Ras also does for NORE1A. PI3K is recruited and allosterically activated by RTK (e.g., EGFR) at the membrane. Ras restrains PI3K's distribution and active site orientation. It stabilizes and facilitates PIP2 binding at the active site and increases the PI3K residence time at the membrane. Thus, RTKs allosterically activate PI3Kα; however, merging their action with Ras accomplishes full activation. Here we review their activation mechanisms in this light and draw attention to implications for their pharmacology.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, United States.,Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, United States
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD, United States
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37
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Jang H, Banerjee A, Marcus K, Makowski L, Mattos C, Gaponenko V, Nussinov R. The Structural Basis of the Farnesylated and Methylated KRas4B Interaction with Calmodulin. Structure 2019; 27:1647-1659.e4. [PMID: 31495533 DOI: 10.1016/j.str.2019.08.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/31/2019] [Accepted: 08/16/2019] [Indexed: 02/07/2023]
Abstract
Ca2+-calmodulin (CaM) extracts KRas4B from the plasma membrane, suggesting that KRas4B/CaM interaction plays a role in regulating Ras signaling. To gain mechanistic insight, we provide a computational model, supported by experimental structural data, of farnesylated/methylated KRas4B1-185 interacting with CaM in solution and at anionic membranes including signaling lipids. Due to multiple interaction modes, we observe diverse conformational ensembles of the KRas4B-CaM complex. A highly populated conformation reveals the catalytic domain interacting with the N-lobe and the hypervariable region (HVR) wrapping around the linker with the farnesyl docking to the extended CaM's C-lobe pocket. Alternatively, KRas4B can interact with collapsed CaM with the farnesyl penetrating CaM's center. At anionic membranes, CaM interacts with the catalytic domain with large fluctuations, drawing the HVR. Signaling lipids establishing strong salt bridges with CaM prevent membrane departure. Membrane-interacting KRas4B-CaM complex can productively recruit phosphatidylinositol 3-kinase α (PI3Kα) to the plasma membrane, serving as a coagent in activating PI3Kα/Akt signaling.
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Affiliation(s)
- Hyunbum Jang
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Avik Banerjee
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Kendra Marcus
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Lee Makowski
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
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