51
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Raman D, Pervaiz S. Redox inhibition of protein phosphatase PP2A: Potential implications in oncogenesis and its progression. Redox Biol 2019; 27:101105. [PMID: 30686777 PMCID: PMC6859563 DOI: 10.1016/j.redox.2019.101105] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 01/17/2023] Open
Abstract
Cellular processes are dictated by the active signaling of proteins relaying messages to regulate cell proliferation, apoptosis, signal transduction and cell communications. An intricate web of protein kinases and phosphatases are critical to the proper transmission of signals across such cascades. By governing 30–50% of all protein dephosphorylation in the cell, with prominent substrate proteins being key regulators of signaling cascades, the phosphatase PP2A has emerged as a celebrated player in various developmental and tumorigenic pathways, thereby posing as an attractive target for therapeutic intervention in various pathologies wherein its activity is deregulated. This review is mainly focused on refreshing our understanding of the structural and functional complexity that cocoons the PP2A phosphatase, and its expression in cancers. Additionally, we focus on its physiological regulation as well as into recent advents and strategies that have shown promise in countering the deregulation of the phosphatase through its targeted reactivation. Finally, we dwell upon one of the key regulators of PP2A in cancer cells-cellular redox status-its multifarious nature, and its integration into the reactome of PP2A, highlighting some of the significant impacts that ROS can inflict on the structural modifications and functional aspect of PP2A.
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Affiliation(s)
- Deepika Raman
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shazib Pervaiz
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Medical Science Cluster Cancer Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; National University Cancer Institute, National University Health System, Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore.
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52
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Fowle H, Zhao Z, Graña X. PP2A holoenzymes, substrate specificity driving cellular functions and deregulation in cancer. Adv Cancer Res 2019; 144:55-93. [PMID: 31349904 PMCID: PMC9994639 DOI: 10.1016/bs.acr.2019.03.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PP2A is a highly conserved eukaryotic serine/threonine protein phosphatase of the PPP family of phosphatases with fundamental cellular functions. In cells, PP2A targets specific subcellular locations and substrates by forming heterotrimeric holoenzymes, where a core dimer consisting of scaffold (A) and catalytic (C) subunits complexes with one of many B regulatory subunits. PP2A plays a key role in positively and negatively regulating a myriad of cellular processes, as it targets a very sizable fraction of the cellular substrates phosphorylated on Ser/Thr residues. This review focuses on insights made toward the understanding on how the subunit composition and structure of PP2A holoenzymes mediates substrate specificity, the role of substrate modulation in the signaling of cellular division, growth, and differentiation, and its deregulation in cancer.
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Affiliation(s)
- Holly Fowle
- Fels Institute for Cancer Research and Molecular Biology and Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States
| | - Ziran Zhao
- Fels Institute for Cancer Research and Molecular Biology and Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States
| | - Xavier Graña
- Fels Institute for Cancer Research and Molecular Biology and Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States.
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53
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Allen-Petersen BL, Risom T, Feng Z, Wang Z, Jenny ZP, Thoma MC, Pelz KR, Morton JP, Sansom OJ, Lopez CD, Sheppard B, Christensen DJ, Ohlmeyer M, Narla G, Sears RC. Activation of PP2A and Inhibition of mTOR Synergistically Reduce MYC Signaling and Decrease Tumor Growth in Pancreatic Ductal Adenocarcinoma. Cancer Res 2019; 79:209-219. [PMID: 30389701 PMCID: PMC6318036 DOI: 10.1158/0008-5472.can-18-0717] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 08/16/2018] [Accepted: 10/26/2018] [Indexed: 12/26/2022]
Abstract
In cancer, kinases are often activated and phosphatases suppressed, leading to aberrant activation of signaling pathways driving cellular proliferation, survival, and therapeutic resistance. Although pancreatic ductal adenocarcinoma (PDA) has historically been refractory to kinase inhibition, therapeutic activation of phosphatases is emerging as a promising strategy to restore balance to these hyperactive signaling cascades. In this study, we hypothesized that phosphatase activation combined with kinase inhibition could deplete oncogenic survival signals to reduce tumor growth. We screened PDA cell lines for kinase inhibitors that could synergize with activation of protein phosphatase 2A (PP2A), a tumor suppressor phosphatase, and determined that activation of PP2A and inhibition of mTOR synergistically increase apoptosis and reduce oncogenic phenotypes in vitro and in vivo. This combination treatment resulted in suppression of AKT/mTOR signaling coupled with reduced expression of c-MYC, an oncoprotein implicated in tumor progression and therapeutic resistance. Forced expression of c-MYC or loss of PP2A B56α, the specific PP2A subunit shown to negatively regulate c-MYC, increased resistance to mTOR inhibition. Conversely, decreased c-MYC expression increased the sensitivity of PDA cells to mTOR inhibition. Together, these studies demonstrate that combined targeting of PP2A and mTOR suppresses proliferative signaling and induces cell death and implicates this combination as a promising therapeutic strategy for patients with PDA. SIGNIFICANCE: These findings present a combinatorial strategy targeting serine/threonine protein phosphatase PP2A and mTOR in PDA, a cancer for which there are currently no targeted therapeutic options.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/1/209/F1.large.jpg.
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Affiliation(s)
- Brittany L Allen-Petersen
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon
| | - Tyler Risom
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon
| | - Zipei Feng
- Department of Cell, Developmental & Cancer Biology, Oregon Health and Science University, Portland, Oregon
| | - Zhiping Wang
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon
| | - Zina P Jenny
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon
| | - Mary C Thoma
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon
| | - Katherine R Pelz
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon
| | - Jennifer P Morton
- CRUK Beatson Institute, Glasgow, Scotland, United Kingdom
- Institute of Cancer Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Owen J Sansom
- CRUK Beatson Institute, Glasgow, Scotland, United Kingdom
- Institute of Cancer Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Charles D Lopez
- Department of Hematology and Oncology, Oregon Health and Science University, Portland, Oregon
| | - Brett Sheppard
- Department of Surgery, Oregon Health and Science University, Portland, Oregon
| | | | | | - Goutham Narla
- School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Rosalie C Sears
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon.
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54
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Fujiki H, Sueoka E, Watanabe T, Suganuma M. The concept of the okadaic acid class of tumor promoters is revived in endogenous protein inhibitors of protein phosphatase 2A, SET and CIP2A, in human cancers. J Cancer Res Clin Oncol 2018; 144:2339-2349. [PMID: 30341686 PMCID: PMC6244643 DOI: 10.1007/s00432-018-2765-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/04/2018] [Indexed: 01/27/2023]
Abstract
PURPOSE The okadaic acid class of tumor promoters, which are inhibitors of protein phosphatases 1 and 2A (PP1 and PP2A), induced tumor promotion in mouse skin, rat glandular stomach, and rat liver. Endogenous protein inhibitors of PP2A, SET and CIP2A, were up-regulated in various human cancers, so it is vital to review the essential mechanisms of tumor promotion by the okadaic acid class compounds, together with cancer progression by SET and CIP2A in humans. RESULTS AND DISCUSSION The first part of this review introduces the okadaic acid class compounds and the mechanism of tumor promotion: (1) inhibition of PP1 and PP2A activities of the okadaic acid class compounds; (2) some topics of tumor promotion; (3) TNF-α gene expression as a central mediator in tumor promotion; (4) exposure to the okadaic acid class of tumor promoters in relation to human cancer. The second part emphasizes the overexpression of SET and CIP2A in cancer progression, and the anticancer activity of SET antagonists as follows: (5) isolation and characterization of SET; (6) isolation and characterization of CIP2A; (7) progression of leukemia with SET; (8) progression of breast cancer with SET and CIP2A; (9) progression of lung cancer with SET; (10) anti-carcinogenic effects of SET antagonists OP449 and FTY720; and also (11) TNF-α-inducing protein of Helicobacter pylori, which is a clinical example of the okadaic acid pathway. CONCLUSIONS The overexpression of endogenous protein inhibitors of PP2A, SET and CIP2A, is tightly linked to the progression of various human cancers, as well as Alzheimer's disease.
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Affiliation(s)
- Hirota Fujiki
- Faculty of Medicine, Saga University, Nabeshima, Saga 849-8501 Japan
| | - Eisaburo Sueoka
- Faculty of Medicine, Saga University, Nabeshima, Saga 849-8501 Japan
| | - Tatsuro Watanabe
- Faculty of Medicine, Saga University, Nabeshima, Saga 849-8501 Japan
| | - Masami Suganuma
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570 Japan
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55
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Brander DM, Friedman DR, Volkheimer AD, Christensen DJ, Rassenti LZ, Kipps TJ, Guadalupe E, Chen Y, Zhang D, Wang X, Davis C, Owzar K, Weinberg JB. SET alpha and SET beta mRNA isoforms in chronic lymphocytic leukaemia. Br J Haematol 2018; 184:605-615. [PMID: 30443898 DOI: 10.1111/bjh.15677] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 09/04/2018] [Indexed: 01/01/2023]
Abstract
Alteration in RNA splicing is implicated in carcinogenesis and progression. Mutations in spliceosome genes and alternative splicing of other genes have been noted in chronic lymphocytic leukaemia (CLL), a common B cell malignancy with heterogeneous outcomes. We previously demonstrated that differences in the amount of SET oncoprotein (a physiological inhibitor of the serine/threonine phosphatase, PP2A) is associated with clinical aggressiveness in patients with CLL. It is unknown if alternative splicing of gene transcripts regulating kinases and phosphatases affects disease pathobiology and CLL progression. We show here for the first time that mRNA levels of the alternatively spliced SET isoforms, SETA and SETB (SETα and SETβ), significantly correlate with disease severity (overall survival and time-to-first-treatment) in CLL patients. In addition, we demonstrate that relative increase of SETA to SETB mRNA can discriminate patients with a more aggressive disease course within the otherwise favourable CLL risk classifications of IGHV mutated and favourable hierarchical fluorescence in situ hybridisation groups. We validate our finding by showing comparable relationships of SET mRNA with disease outcomes using samples from an independent CLL cohort from a separate institution. These findings indicate that alternative splicing of SET, and potentially other signalling cascade molecules, influences CLL biology and patient outcomes.
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Affiliation(s)
- Danielle M Brander
- Duke University Medical Center, Durham, NC, USA.,Duke Cancer Institute, Durham, NC, USA
| | - Daphne R Friedman
- Duke University Medical Center, Durham, NC, USA.,Duke Cancer Institute, Durham, NC, USA.,Durham VA Medical Center, Durham, NC, USA
| | | | | | - Laura Z Rassenti
- University of California San Diego Moores Cancer Center, San Diego, CA, USA
| | - Thomas J Kipps
- University of California San Diego Moores Cancer Center, San Diego, CA, USA
| | | | - Youwei Chen
- Duke University Medical Center, Durham, NC, USA
| | - Dadong Zhang
- Duke University Medical Center, Durham, NC, USA.,Duke Cancer Institute, Durham, NC, USA
| | - Xi Wang
- Duke University Medical Center, Durham, NC, USA.,Duke Cancer Institute, Durham, NC, USA
| | | | - Kouros Owzar
- Duke University Medical Center, Durham, NC, USA.,Duke Cancer Institute, Durham, NC, USA
| | - J Brice Weinberg
- Duke University Medical Center, Durham, NC, USA.,Duke Cancer Institute, Durham, NC, USA.,Durham VA Medical Center, Durham, NC, USA
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56
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Williams AP, Garner EF, Waters AM, Stafman LL, Aye JM, Markert H, Stewart JE, Beierle EA. Investigation of PP2A and Its Endogenous Inhibitors in Neuroblastoma Cell Survival and Tumor Growth. Transl Oncol 2018; 12:84-95. [PMID: 30286326 PMCID: PMC6169101 DOI: 10.1016/j.tranon.2018.09.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 12/22/2022] Open
Abstract
High-risk neuroblastoma continues to carry a poor prognosis. Nearly 50% of these tumors relapse following extensive treatment regimens. Protein phosphatase 2A (PP2A), a tumor suppressor, has been shown to be downregulated in many human cancers via multiple mechanisms including upregulation of its endogenous inhibitors, I2PP2A or CIP2A. We hypothesized that inhibition of the endogenous PP2A inhibitors or activation of PP2A would decrease tumorigenicity in human neuroblastoma cells. Four human neuroblastoma cell lines were utilized. Expression of PP2A and its endogenous inhibitors I2PP2A and CIP2A was confirmed by immunoblotting. PP2A activation was measured via phosphatase activation assay. Multiple parallel methods including siRNA inhibition of the endogenous PP2A inhibitors and pharmacologic activation of PP2A were utilized. Cell viability, proliferation, migration, and invasion assays were performed. In vivo studies were utilized to determine the effects of PP2A activation on neuroblastoma tumor growth. Inhibition of the endogenous inhibitors of PP2A or pharmacologic activation of PP2A with the PP2A activator FTY720 led to decreased neuroblastoma cell viability, proliferation, migration, and invasion. Treatment of mice bearing SK-N-AS or SK-N-BE(2) neuroblastoma tumors with FTY720 resulted in a significant decrease in tumor growth compared to vehicle-treated animals. In conclusion, activation of PP2A may provide a novel therapeutic target for neuroblastoma.
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Affiliation(s)
- Adele P Williams
- Division of Pediatric Surgery, Department of Surgery, University of Alabama, Birmingham, Birmingham, AL
| | - Evan F Garner
- Division of Pediatric Surgery, Department of Surgery, University of Alabama, Birmingham, Birmingham, AL
| | - Alicia M Waters
- Division of Pediatric Surgery, Department of Surgery, University of Alabama, Birmingham, Birmingham, AL
| | - Laura L Stafman
- Division of Pediatric Surgery, Department of Surgery, University of Alabama, Birmingham, Birmingham, AL
| | - Jamie M Aye
- Division of Hematology and Oncology Department of Pediatrics, University of Alabama, Birmingham, Birmingham, AL
| | - Hooper Markert
- Division of Pediatric Surgery, Department of Surgery, University of Alabama, Birmingham, Birmingham, AL
| | - Jerry E Stewart
- Division of Pediatric Surgery, Department of Surgery, University of Alabama, Birmingham, Birmingham, AL
| | - Elizabeth A Beierle
- Division of Pediatric Surgery, Department of Surgery, University of Alabama, Birmingham, Birmingham, AL.
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57
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Mazhar S, Taylor SE, Sangodkar J, Narla G. Targeting PP2A in cancer: Combination therapies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:51-63. [PMID: 30401535 DOI: 10.1016/j.bbamcr.2018.08.020] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/21/2018] [Accepted: 08/28/2018] [Indexed: 12/12/2022]
Abstract
The serine/threonine phosphatase PP2A regulates a vast portion of the phosphoproteome including pathways involved in apoptosis, proliferation and DNA damage response and PP2A inactivation is a vital step in malignant transformation. Many groups have explored the therapeutic venue of combining PP2A reactivation with kinase inhibition to counteract the very changes in tumor suppressors and oncogenes that lead to cancer development. Conversely, inhibition of PP2A to complement chemotherapy and radiation-induced cancer cell death is also an area of active investigation. Here we review the studies that utilize PP2A targeted agents as combination therapy in cancer. A potential role for PP2A in tumor immunity is also highlighted.
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Affiliation(s)
- Sahar Mazhar
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah E Taylor
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Jaya Sangodkar
- Division of Genetic Medicine, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Goutham Narla
- Division of Genetic Medicine, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
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58
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Narla G, Sangodkar J, Ryder CB. The impact of phosphatases on proliferative and survival signaling in cancer. Cell Mol Life Sci 2018; 75:2695-2718. [PMID: 29725697 PMCID: PMC6023766 DOI: 10.1007/s00018-018-2826-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 03/24/2018] [Accepted: 04/23/2018] [Indexed: 02/06/2023]
Abstract
The dynamic and stringent coordination of kinase and phosphatase activity controls a myriad of physiologic processes. Aberrations that disrupt the balance of this interplay represent the basis of numerous diseases. For a variety of reasons, early work in this area portrayed kinases as the dominant actors in these signaling events with phosphatases playing a secondary role. In oncology, these efforts led to breakthroughs that have dramatically altered the course of certain diseases and directed vast resources toward the development of additional kinase-targeted therapies. Yet, more recent scientific efforts have demonstrated a prominent and sometimes driving role for phosphatases across numerous malignancies. This maturation of the phosphatase field has brought with it the promise of further therapeutic advances in the field of oncology. In this review, we discuss the role of phosphatases in the regulation of cellular proliferation and survival signaling using the examples of the MAPK and PI3K/AKT pathways, c-Myc and the apoptosis machinery. Emphasis is placed on instances where these signaling networks are perturbed by dysregulation of specific phosphatases to favor growth and persistence of human cancer.
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Affiliation(s)
| | - Jaya Sangodkar
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
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59
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Huang CY, Hung MH, Shih CT, Hsieh FS, Kuo CW, Tsai MH, Chang SS, Hsiao YJ, Chen LJ, Chao TI, Chen KF. Antagonizing SET Augments the Effects of Radiation Therapy in Hepatocellular Carcinoma through Reactivation of PP2A-Mediated Akt Downregulation. J Pharmacol Exp Ther 2018; 366:410-421. [PMID: 29914877 DOI: 10.1124/jpet.118.249102] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/13/2018] [Indexed: 12/23/2022] Open
Abstract
Increasing evidence suggests that SET functions as an oncoprotein and promotes cancer survival and therapeutic resistance. However, whether SET affects radiation therapy (RT)-mediated anticancer effects has not yet been explored. We investigated the impact of SET on RT sensitivity in hepatocellular carcinoma (HCC). Using colony and hepatosphere formation assays, we found that RT-induced proliferative inhibition was critically associated with SET expression. We next tested a novel SET antagonist, N4-(3-ethynylphenyl)-6,7-dimethoxy-N2-(4-phenoxyphenyl) quinazoline-2,4-diamine (EMQA), in combination with RT. We showed that additive use of EMQA significantly enhanced the effects of RT against HCC in vitro and in vivo. Notably, compared with mice receiving either RT or EMQA alone, the growth of PLC5 xenografted tumor in mice receiving RT plus EMQA was significantly reduced without compromising treatment tolerability. Furthermore, we proved that antagonizing SET to restore protein phosphatase 2A-mediated phospho-Akt (p-AKT) downregulation was responsible for the synergism between EMQA and RT. Our data demonstrate a new oncogenic property of SET and provide preclinical evidence that combining a SET antagonist and RT may be effective for treatment of HCC. Further investigation is warranted to validate the clinical relevance of this approach.
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Affiliation(s)
- Chao-Yuan Huang
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Man-Hsin Hung
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Chi-Ting Shih
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Feng-Shu Hsieh
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Chiung-Wen Kuo
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Ming-Hsien Tsai
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Shih-Shin Chang
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Yung-Jen Hsiao
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Li-Ju Chen
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Tzu-I Chao
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
| | - Kuen-Feng Chen
- Division of Radiation Oncology, Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan (C.-Y.H.); Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan (M.-H.H.); Institute of Biopharmaceutical Sciences (C.-T.S.) and School of Medicine (M.-H.H.), National Yang-Ming University, Taipei, Taiwan; Department of Medical Research (F.-S.H., M.-H.T., S.-S.C., Y.-J.H, L.-J.C., K.-F.C.) and National Center of Excellence for Clinical Trial and Research (K.-F.C.), National Taiwan University Hospital, Taipei, Taiwan; Department of Medical Imaging and Radiological Technology, Yuanpei University, Hsinchu, Taiwan (C.-Y.H., C.-W.K.); and SupremeCure Pharma Inc., Taipei, Taiwan (T.-I.C.)
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60
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Bayarkhangai B, Noureldin S, Yu L, Zhao N, Gu Y, Xu H, Guo C. A comprehensive and perspective view of oncoprotein SET in cancer. Cancer Med 2018; 7:3084-3094. [PMID: 29749127 PMCID: PMC6051184 DOI: 10.1002/cam4.1526] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/25/2018] [Accepted: 04/05/2018] [Indexed: 12/16/2022] Open
Abstract
SET is a multifunctional oncoprotein which is ubiquitously expressed in all kinds of cells. The SET protein participates in many cellular processes including cell cycle, cell migration, apoptosis, transcription, and DNA repair. Accumulating evidence demonstrates that the expression and activity of SET correlate with cancer occurrence, metastasis, and prognosis. Therefore, the SET protein is regarded as a potential target for cancer therapy and several inhibitors are being developed for clinical use. Herein, we comprehensively review the physiological and pathological functions of SET as well as its structure-function relationship. Additionally, the regulatory mechanisms of SET at both transcriptional and posttranslational levels are also discussed.
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Affiliation(s)
- Buuvee Bayarkhangai
- State Key of Natural Medicine, China Pharmaceutical University, Nanjing, China
| | - Suzan Noureldin
- State Key of Natural Medicine, China Pharmaceutical University, Nanjing, China
| | - Liting Yu
- State Key of Natural Medicine, China Pharmaceutical University, Nanjing, China
| | - Na Zhao
- State Key of Natural Medicine, China Pharmaceutical University, Nanjing, China
| | - Yaru Gu
- State Key of Natural Medicine, China Pharmaceutical University, Nanjing, China
| | - Hanmei Xu
- State Key of Natural Medicine, China Pharmaceutical University, Nanjing, China
| | - Changying Guo
- State Key of Natural Medicine, China Pharmaceutical University, Nanjing, China
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61
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Larrosa-Garcia M, Baer MR. FLT3 Inhibitors in Acute Myeloid Leukemia: Current Status and Future Directions. Mol Cancer Ther 2018; 16:991-1001. [PMID: 28576946 DOI: 10.1158/1535-7163.mct-16-0876] [Citation(s) in RCA: 205] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 01/13/2017] [Accepted: 04/05/2017] [Indexed: 12/11/2022]
Abstract
The receptor tyrosine kinase fms-like tyrosine kinase 3 (FLT3), involved in regulating survival, proliferation, and differentiation of hematopoietic stem/progenitor cells, is expressed on acute myeloid leukemia (AML) cells in most patients. Mutations of FLT3 resulting in constitutive signaling are common in AML, including internal tandem duplication (ITD) in the juxtamembrane domain in 25% of patients and point mutations in the tyrosine kinase domain in 5%. Patients with AML with FLT3-ITD have a high relapse rate and short relapse-free and overall survival after chemotherapy and after transplant. A number of inhibitors of FLT3 signaling have been identified and are in clinical trials, both alone and with chemotherapy, with the goal of improving clinical outcomes in patients with AML with FLT3 mutations. While inhibitor monotherapy produces clinical responses, they are usually incomplete and transient, and resistance develops rapidly. Diverse combination therapies have been suggested to potentiate the efficacy of FLT3 inhibitors and to prevent development of resistance or overcome resistance. Combinations with epigenetic therapies, proteasome inhibitors, downstream kinase inhibitors, phosphatase activators, and other drugs that alter signaling are being explored. This review summarizes the current status of translational and clinical research on FLT3 inhibitors in AML, and discusses novel combination approaches. Mol Cancer Ther; 16(6); 991-1001. ©2017 AACR.
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MESH Headings
- Animals
- Antineoplastic Combined Chemotherapy Protocols/adverse effects
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- Clinical Trials as Topic
- Drug Evaluation, Preclinical
- Drug Resistance, Neoplasm/genetics
- Humans
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/mortality
- Leukemia, Myeloid, Acute/pathology
- Mutation
- Protein Binding
- Protein Interaction Domains and Motifs
- Protein Kinase Inhibitors/pharmacology
- Protein Kinase Inhibitors/therapeutic use
- Protein Multimerization
- Tandem Repeat Sequences
- Treatment Outcome
- fms-Like Tyrosine Kinase 3/antagonists & inhibitors
- fms-Like Tyrosine Kinase 3/chemistry
- fms-Like Tyrosine Kinase 3/genetics
- fms-Like Tyrosine Kinase 3/metabolism
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Affiliation(s)
- Maria Larrosa-Garcia
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, Maryland
| | - Maria R Baer
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, Maryland.
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland
- Veterans Affairs Medical Center, Baltimore, Maryland
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62
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Richard NP, Pippa R, Cleary MM, Puri A, Tibbitts D, Mahmood S, Christensen DJ, Jeng S, McWeeney S, Look AT, Chang BH, Tyner JW, Vitek MP, Odero MD, Sears R, Agarwal A. Combined targeting of SET and tyrosine kinases provides an effective therapeutic approach in human T-cell acute lymphoblastic leukemia. Oncotarget 2018; 7:84214-84227. [PMID: 27705940 PMCID: PMC5356656 DOI: 10.18632/oncotarget.12394] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 09/24/2016] [Indexed: 12/21/2022] Open
Abstract
Recent evidence suggests that inhibition of protein phosphatase 2A (PP2A) tumor suppressor activity via the SET oncoprotein contributes to the pathogenesis of various cancers. Here we demonstrate that both SET and c-MYC expression are frequently elevated in T-ALL cell lines and primary samples compared to healthy T cells. Treatment of T-ALL cells with the SET antagonist OP449 restored the activity of PP2A and reduced SET interaction with the PP2A catalytic subunit, resulting in a decrease in cell viability and c-MYC expression in a dose-dependent manner. Since a tight balance between phosphatases and kinases is required for the growth of both normal and malignant cells, we sought to identify a kinase inhibitor that would synergize with SET antagonism. We tested various T-ALL cell lines against a small-molecule inhibitor screen of 66 compounds targeting two-thirds of the tyrosine kinome and found that combined treatment of T-ALL cells with dovitinib, an orally active multi-targeted small-molecule receptor tyrosine kinase inhibitor, and OP449 synergistically reduced the viability of all tested T-ALL cell lines. Mechanistically, combined treatment with OP449 and dovitinib decreased total and phospho c-MYC levels and reduced ERK1/2, AKT, and p70S6 kinase activity in both NOTCH-dependent and independent T-ALL cell lines. Overall, these results suggest that combined targeting of tyrosine kinases and activation of serine/threonine phosphatases may offer novel therapeutic strategies for the treatment of T-ALL.
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Affiliation(s)
- Nameeta P Richard
- Randall Children's Hospital at Legacy Emanuel, Children's Cancer and Blood Disorders Program, Portland, OR 97227, USA.,Division of Pediatric Hematology Oncology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Raffaella Pippa
- Division of Oncology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
| | - Megan M Cleary
- Division of Hematology and Medical Oncology, Oregon Health and Science University, Portland, OR 97239, USA.,Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Alka Puri
- Division of Hematology and Medical Oncology, Oregon Health and Science University, Portland, OR 97239, USA.,Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Deanne Tibbitts
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR 97239, USA
| | - Shawn Mahmood
- Division of Hematology and Medical Oncology, Oregon Health and Science University, Portland, OR 97239, USA.,Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Dale J Christensen
- Research and Development, Oncotide Pharmaceuticals, Research Triangle Park, NC 27710, USA .,Spyryx Biosciences, Durham, NC 27713, USA
| | - Sophia Jeng
- Division of Bioinformatics and Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, Portland, OR 97239, USA.,Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Shannon McWeeney
- Division of Bioinformatics and Computational Biology, Department of Medical Informatics and Clinical Epidemiology, Oregon Health and Science University, Portland, OR 97239, USA.,Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - A Thomas Look
- Dana-Farber Cancer Institute, Harvard Cancer Center, Boston, MA 02215, USA
| | - Bill H Chang
- Division of Pediatric Hematology Oncology, Oregon Health and Science University, Portland, OR 97239, USA.,Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Jeffrey W Tyner
- Department of Cell and Developmental Biology, Oregon Health and Science University, Portland, OR 97239, USA.,Knight Cancer Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Michael P Vitek
- Research and Development, Oncotide Pharmaceuticals, Research Triangle Park, NC 27710, USA
| | - María D Odero
- Division of Oncology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
| | - Rosalie Sears
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR USA-97239.,Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA-97239
| | - Anupriya Agarwal
- Division of Hematology and Medical Oncology, Oregon Health and Science University, Portland, OR, USA-97239.,Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR USA-97239.,Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA-97239
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63
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Kauko O, Westermarck J. Non-genomic mechanisms of protein phosphatase 2A (PP2A) regulation in cancer. Int J Biochem Cell Biol 2018; 96:157-164. [DOI: 10.1016/j.biocel.2018.01.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 12/03/2017] [Accepted: 01/09/2018] [Indexed: 02/08/2023]
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64
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Weng S, Stoner SA, Zhang DE. Sex chromosome loss and the pseudoautosomal region genes in hematological malignancies. Oncotarget 2018; 7:72356-72372. [PMID: 27655702 PMCID: PMC5342167 DOI: 10.18632/oncotarget.12050] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 09/07/2016] [Indexed: 11/25/2022] Open
Abstract
Cytogenetic aberrations, such as chromosomal translocations, aneuploidy, and amplifications, are frequently detected in hematological malignancies. For many of the common autosomal aberrations, the mechanisms underlying their roles in cancer development have been well-characterized. On the contrary, although loss of a sex chromosome is observed in a broad range of hematological malignancies, how it cooperates in disease development is less understood. Nevertheless, it has been postulated that tumor suppressor genes reside on the sex chromosomes. Although the X and Y sex chromosomes are highly divergent, the pseudoautosomal regions are homologous between both chromosomes. Here, we review what is currently known about the pseudoautosomal region genes in the hematological system. Additionally, we discuss implications for haploinsufficiency of critical pseudoautosomal region sex chromosome genes, driven by sex chromosome loss, in promoting hematological malignancies. Because mechanistic studies on disease development rely heavily on murine models, we also discuss the challenges and caveats of existing models, and propose alternatives for examining the involvement of pseudoautosomal region genes and loss of a sex chromosome in vivo. With the widespread detection of loss of a sex chromosome in different hematological malignances, the elucidation of the role of pseudoautosomal region genes in the development and progression of these diseases would be invaluable to the field.
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Affiliation(s)
- Stephanie Weng
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Samuel A Stoner
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA
| | - Dong-Er Zhang
- Moores Cancer Center, University of California San Diego, La Jolla, CA, USA.,Department of Pathology and Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
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65
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Smith AM, Dun MD, Lee EM, Harrison C, Kahl R, Flanagan H, Panicker N, Mashkani B, Don AS, Morris J, Toop H, Lock RB, Powell JA, Thomas D, Guthridge MA, Moore A, Ashman LK, Skelding KA, Enjeti A, Verrills NM. Activation of protein phosphatase 2A in FLT3+ acute myeloid leukemia cells enhances the cytotoxicity of FLT3 tyrosine kinase inhibitors. Oncotarget 2018; 7:47465-47478. [PMID: 27329844 PMCID: PMC5216954 DOI: 10.18632/oncotarget.10167] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/06/2016] [Indexed: 11/25/2022] Open
Abstract
Constitutive activation of the receptor tyrosine kinase Fms-like tyrosine kinase 3 (FLT3), via co-expression of its ligand or by genetic mutation, is common in acute myeloid leukemia (AML). In this study we show that FLT3 activation inhibits the activity of the tumor suppressor, protein phosphatase 2A (PP2A). Using BaF3 cells transduced with wildtype or mutant FLT3, we show that FLT3-induced PP2A inhibition sensitizes cells to the pharmacological PP2A activators, FTY720 and AAL(S). FTY720 and AAL(S) induced cell death and inhibited colony formation of FLT3 activated cells. Furthermore, PP2A activators reduced the phosphorylation of ERK and AKT, downstream targets shared by both FLT3 and PP2A, in FLT3/ITD+ BaF3 and MV4-11 cell lines. PP2A activity was lower in primary human bone marrow derived AML blasts compared to normal bone marrow, with blasts from FLT3-ITD patients displaying lower PP2A activity than WT-FLT3 blasts. Reduced PP2A activity was associated with hyperphosphorylation of the PP2A catalytic subunit, and reduced expression of PP2A structural and regulatory subunits. AML patient blasts were also sensitive to cell death induced by FTY720 and AAL(S), but these compounds had minimal effect on normal CD34+ bone marrow derived monocytes. Finally, PP2A activating compounds displayed synergistic effects when used in combination with tyrosine kinase inhibitors in FLT3-ITD+ cells. A combination of Sorafenib and FTY720 was also synergistic in the presence of a protective stromal microenvironment. Thus combining a PP2A activating compound and a FLT3 inhibitor may be a novel therapeutic approach for treating AML.
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Affiliation(s)
- Amanda M Smith
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia.,Current address: The University of Queensland Diamantina Institute, Woolloongabba, Queensland, Australia
| | - Matthew D Dun
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia
| | - Erwin M Lee
- Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, UNSW, Sydney, New South Wales, Australia
| | - Celeste Harrison
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia
| | - Richard Kahl
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia
| | - Hayley Flanagan
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia
| | - Nikita Panicker
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia
| | - Baratali Mashkani
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia.,Current address: Department of Medical Biochemistry, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Anthony S Don
- Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Jonathan Morris
- School of Chemistry, University of New South Wales, Sydney, New South Wales, Australia
| | - Hamish Toop
- School of Chemistry, University of New South Wales, Sydney, New South Wales, Australia
| | - Richard B Lock
- Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, UNSW, Sydney, New South Wales, Australia
| | - Jason A Powell
- Centre for Cancer Biology, SA Pathology, Adelaide, South Australia, Australia
| | - Daniel Thomas
- Centre for Cancer Biology, SA Pathology, Adelaide, South Australia, Australia.,Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Mark A Guthridge
- Department Clinical Haematology, Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria, Australia
| | - Andrew Moore
- Translational Research Institute, The University of Queensland Diamantina Institute, Woolloongabba, Queensland, Australia
| | - Leonie K Ashman
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia
| | - Kathryn A Skelding
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia
| | - Anoop Enjeti
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia.,Calvary Mater Hospital, Newcastle, New South Wales, Australia
| | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia.,Hunter Medical Research Institute, Newcastle, New South Wales, Australia
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66
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Enjoji S, Yabe R, Tsuji S, Yoshimura K, Kawasaki H, Sakurai M, Sakai Y, Takenouchi H, Yoshino S, Hazama S, Nagano H, Oshima H, Oshima M, Vitek MP, Matsuura T, Hippo Y, Usui T, Ohama T, Sato K. Stemness Is Enhanced in Gastric Cancer by a SET/PP2A/E2F1 Axis. Mol Cancer Res 2018; 16:554-563. [PMID: 29330298 DOI: 10.1158/1541-7786.mcr-17-0393] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/10/2017] [Accepted: 12/13/2017] [Indexed: 11/16/2022]
Abstract
Gastric cancer is the fifth most common malignancy and the third leading cause of cancer-related deaths worldwide. Chemotherapies against gastric cancer often fail, with cancer recurrence due potentially to the persistence of cancer stem cells. This unique subpopulation of cells in tumors possesses the ability to self-renew and dedifferentiate. These cancer stem cells are critical for initiation, maintenance, metastasis, and relapse of cancers; however, the molecular mechanisms supporting cancer stemness remain largely unknown. Increased kinase and decreased phosphatase activity are hallmarks of oncogenic signaling. Protein phosphatase 2A (PP2A) functions as a tumor-suppressor enzyme, and elevated levels of SET/I2PP2A, an endogenous PP2A protein inhibitor, are correlated with poor prognosis of several human cancers. Here, it was determined that SET expression was elevated in tumor tissue in a gastric cancer mouse model system, and SET expression was positively correlated with poor survival of human gastric cancer patients. Mechanistically, SET knockdown decreased E2F1 levels and suppressed the stemness of cancer cell lines. Immunoprecipitations show SET associated with the PP2A-B56 complex, and the B56 subunit interacted with the E2F1 transcription factor. Treatment of gastric cancer cells with the SET-targeting drug OP449 increased PP2A activity, decreased E2F1 protein levels, and suppressed stemness of cancer cells. These data indicate that a SET/PP2A/E2F1 axis regulates cancer cell stemness and is a potential target for gastric cancer therapy.Implications: This study highlights the oncogenic role of SET/I2PP2A in gastric cancer and suggests that SET maintains cancer cell stemness by suppressing PP2A activity and stabilizing E2F1. Mol Cancer Res; 16(3); 554-63. ©2018 AACR.
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Affiliation(s)
- Shuhei Enjoji
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Ryotaro Yabe
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Shunya Tsuji
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Kazuhiro Yoshimura
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Hideyoshi Kawasaki
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Masashi Sakurai
- Laboratory of Veterinary Pathology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Yusuke Sakai
- Laboratory of Veterinary Pathology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Hiroko Takenouchi
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | | | - Shoichi Hazama
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Hiroaki Nagano
- Department of Gastroenterological, Breast and Endocrine Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Hiroko Oshima
- Division of Genetics, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Masanobu Oshima
- Division of Genetics, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Michael P Vitek
- Department of Neurology, Duke University Medical Center, Durham, North Carolina.,Oncotide Pharmaceuticals, Inc., Research Triangle Park, North Carolina
| | - Tetsuya Matsuura
- Department of Gastroenterology and Hepatology, Yokohama City University School of Medicine, Kanagawa, Japan
| | | | - Tatsuya Usui
- Laboratory of Veterinary Toxicology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Takashi Ohama
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan.
| | - Koichi Sato
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan
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67
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Zhao H, Li D, Zhang B, Qi Y, Diao Y, Zhen Y, Shu X. PP2A as the Main Node of Therapeutic Strategies and Resistance Reversal in Triple-Negative Breast Cancer. Molecules 2017; 22:molecules22122277. [PMID: 29261144 PMCID: PMC6149800 DOI: 10.3390/molecules22122277] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/07/2017] [Accepted: 12/19/2017] [Indexed: 12/31/2022] Open
Abstract
Triple negative breast cancer (TNBC), is defined as a type of tumor lacking the expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2). The ER, PR and HER2 are usually the molecular therapeutic targets for breast cancers, but they are ineffective for TNBC because of their negative expressions, so chemotherapy is currently the main treatment strategy in TNBC. However, drug resistance remains a major impediment to TNBC chemotherapeutic treatment. Recently, the protein phosphatase 2A (PP2A) has been found to regulate the phosphorylation of some substrates involved in the relevant target of TNBC, such as cell cycle control, DNA damage responses, epidermal growth factor receptor, immune modulation and cell death resistance, which may be the effective therapeutic strategies or influence drug sensitivity to TNBCs. Furthermore, PP2A has also been found that could induce ER re-expression in ER-negative breast cancer cells, and which suggests PP2A could promote the sensitivity of tamoxifen to TNBCs as a resistance reversal agent. In this review, we will summarize the potential therapeutic value of PP2A as the main node in developing targeting agents, disrupting resistance or restoring drug sensitivity in TNBC.
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Affiliation(s)
- Henan Zhao
- Department of Pathophysiology, Dalian Medical University, Dalian 116044, China.
| | - Duojiao Li
- Kamp Pharmaceutical Co. Ltd., Changsha 410008, China.
| | - Baojing Zhang
- College of Pharmacy, Dalian Medical University, Dalian 116044, China.
| | - Yan Qi
- College of Pharmacy, Dalian Medical University, Dalian 116044, China.
| | - Yunpeng Diao
- College of Pharmacy, Dalian Medical University, Dalian 116044, China.
| | - Yuhong Zhen
- College of Pharmacy, Dalian Medical University, Dalian 116044, China.
| | - Xiaohong Shu
- College of Pharmacy, Dalian Medical University, Dalian 116044, China.
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68
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Janghorban M, Langer EM, Wang X, Zachman D, Daniel CJ, Hooper J, Fleming WH, Agarwal A, Sears RC. The tumor suppressor phosphatase PP2A-B56α regulates stemness and promotes the initiation of malignancies in a novel murine model. PLoS One 2017; 12:e0188910. [PMID: 29190822 PMCID: PMC5708644 DOI: 10.1371/journal.pone.0188910] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 11/15/2017] [Indexed: 01/13/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is a ubiquitously expressed Serine-Threonine phosphatase mediating 30–50% of protein phosphatase activity. PP2A functions as a heterotrimeric complex, with the B subunits directing target specificity to regulate the activity of many key pathways that control cellular phenotypes. PP2A-B56α has been shown to play a tumor suppressor role and to negatively control c-MYC stability and activity. Loss of B56α promotes cellular transformation, likely at least in part through its regulation of c-MYC. Here we report generation of a B56α hypomorph mouse with very low B56α expression that we used to study the physiologic activity of the PP2A-B56α phosphatase. The predominant phenotype we observed in mice with B56α deficiency in the whole body was spontaneous skin lesion formation with hyperproliferation of the epidermis, hair follicles and sebaceous glands. Increased levels of c-MYC phosphorylation on Serine62 and c-MYC activity were observed in the skin lesions of the B56αhm/hm mice. B56α deficiency was found to increase the number of skin stem cells, and consistent with this, papilloma initiation was accelerated in a carcinogenesis model. Further analysis of additional tissues revealed increased inflammation in spleen, liver, lung, and intestinal lymph nodes as well as in the skin lesions, resembling elevated extramedullary hematopoiesis phenotypes in the B56αhm/hm mice. We also observed an increase in the clonogenicity of bone marrow stem cells in B56αhm/hm mice. Overall, this model suggests that B56α is important for stem cells to maintain homeostasis and that B56α loss leading to increased activity of important oncogenes, including c-MYC, can result in aberrant cell growth and increased stem cells that can contribute to the initiation of malignancy.
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Affiliation(s)
- Mahnaz Janghorban
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Ellen M. Langer
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Xiaoyan Wang
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Derek Zachman
- Papé Family Pediatric Research Institute, Oregon Stem Cell Center, Department of Pediatrics, Portland, Oregon, United States of America
| | - Colin J. Daniel
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Jody Hooper
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - William H. Fleming
- Papé Family Pediatric Research Institute, Oregon Stem Cell Center, Department of Pediatrics, Portland, Oregon, United States of America
- Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Anupriya Agarwal
- Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, United States of America
- Division of Hematology & Medical Oncology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Rosalie C. Sears
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, Oregon, United States of America
- Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon, United States of America
- Brenden-Colson Center for Pancreatic Care, Oregon Health and Science University, Portland, Oregon, United States of America
- * E-mail:
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69
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Therapeutic targeting of PP2A. Int J Biochem Cell Biol 2017; 96:182-193. [PMID: 29107183 DOI: 10.1016/j.biocel.2017.10.008] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 10/13/2017] [Accepted: 10/16/2017] [Indexed: 12/19/2022]
Abstract
Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase that regulates many cellular processes. Given the central role of PP2A in regulating diverse biological functions and its dysregulation in many diseases, including cancer, PP2A directed therapeutics have become of great interest. The main approaches leveraged thus far can be categorized as follows: 1) inhibiting endogenous inhibitors of PP2A, 2) targeted disruption of post translational modifications on PP2A subunits, or 3) direct targeting of PP2A. Additional insight into the structural, molecular, and biological framework driving the efficacy of these therapeutic strategies will provide a foundation for the refinement and development of novel and clinically tractable PP2A targeted therapies.
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70
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Meeusen B, Janssens V. Tumor suppressive protein phosphatases in human cancer: Emerging targets for therapeutic intervention and tumor stratification. Int J Biochem Cell Biol 2017; 96:98-134. [PMID: 29031806 DOI: 10.1016/j.biocel.2017.10.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 10/04/2017] [Accepted: 10/05/2017] [Indexed: 02/06/2023]
Abstract
Aberrant protein phosphorylation is one of the hallmarks of cancer cells, and in many cases a prerequisite to sustain tumor development and progression. Like protein kinases, protein phosphatases are key regulators of cell signaling. However, their contribution to aberrant signaling in cancer cells is overall less well appreciated, and therefore, their clinical potential remains largely unexploited. In this review, we provide an overview of tumor suppressive protein phosphatases in human cancer. Along their mechanisms of inactivation in defined cancer contexts, we give an overview of their functional roles in diverse signaling pathways that contribute to their tumor suppressive abilities. Finally, we discuss their emerging roles as predictive or prognostic markers, their potential as synthetic lethality targets, and the current feasibility of their reactivation with pharmacologic compounds as promising new cancer therapies. We conclude that their inclusion in clinical practice has obvious potential to significantly improve therapeutic outcome in various ways, and should now definitely be pushed forward.
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Affiliation(s)
- Bob Meeusen
- Laboratory of Protein Phosphorylation & Proteomics, Dept. of Cellular & Molecular Medicine, Faculty of Medicine, KU Leuven & Leuven Cancer Institute (LKI), KU Leuven, Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation & Proteomics, Dept. of Cellular & Molecular Medicine, Faculty of Medicine, KU Leuven & Leuven Cancer Institute (LKI), KU Leuven, Belgium.
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71
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Tian L, Zhang X, Haesen D, Bravo J, Fominaya J, Choquet S, Zini JM, Loisel S, Waelkens E, Janssens V, Rebollo A. Identification of PP2A/Set Binding Sites and Design of Interacting Peptides with Potential Clinical Applications. Int J Pept Res Ther 2017. [DOI: 10.1007/s10989-017-9633-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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72
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Shlomai G, Zelenko Z, Antoniou IM, Stasinopoulos M, Tobin-Hess A, Vitek MP, LeRoith D, Gallagher EJ. OP449 inhibits breast cancer growth without adverse metabolic effects. Endocr Relat Cancer 2017; 24:519-529. [PMID: 28830934 PMCID: PMC5678946 DOI: 10.1530/erc-17-0077] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 07/21/2017] [Indexed: 12/23/2022]
Abstract
Hyperinsulinemia is associated with a decrease in breast cancer recurrence-free survival and overall survival. Inhibition of insulin receptor signaling is associated with glycemic dysregulation. SET is a direct modulator of PP2A, which negatively regulates the PI3K/AKT/mTOR pathway. OP449, a SET inhibitor, decreases AKT/mTOR activation. The effects of OP449 treatment on breast cancer growth in the setting of pre-diabetes, and its metabolic implications are currently unknown. We found that the volumes and weights of human MDA-MB-231 breast cancer xenografts were greater in hyperinsulinemic mice compared with controls (P < 0.05), and IR phosphorylation was 4.5-fold higher in these mice (P < 0.05). Human and murine breast cancer tumors treated with OP449 were 47% and 39% smaller than controls (P < 0.05, for both, respectively). AKT and S6RP phosphorylation were 82% and 34% lower in OP449-treated tumors compared with controls (P < 0.05, P = 0.06, respectively). AKT and S6RP phosphorylation in response to insulin was 30% and 12% lower in cells, pre-treated with OP449, compared with control cells (P < 0.01, P < 0.05, respectively). However, even with decreased AKT/mTOR activation, body weights and composition, blood glucose and plasma insulin, glucose tolerance, serum triglyceride and cholesterol levels were similar between OP449-treated mice and controls. Xenografts and liver tissue from OP449-treated mice showed a 64% and 70% reduction in STAT5 activation, compared with controls (P < 0.01 and P = 0.06, respectively). Our data support an anti-neoplastic effect of OP449 on human breast cancer cells in vitro and in xenografts in the setting of hyperinsulinemia. OP449 led to the inhibition of AKT/mTOR signaling, albeit, not leading to metabolic derangements.
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Affiliation(s)
- Gadi Shlomai
- Division of EndocrinologyDiabetes and Bone Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA
- The Dr Pinchas Borenstein Talpiot Medical Leadership Program 2013Tel-Hashomer, Israel
| | - Zara Zelenko
- Division of EndocrinologyDiabetes and Bone Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Irini Markella Antoniou
- Division of EndocrinologyDiabetes and Bone Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Marilyn Stasinopoulos
- Division of EndocrinologyDiabetes and Bone Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Aviva Tobin-Hess
- Division of EndocrinologyDiabetes and Bone Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Michael P Vitek
- CognosciInc., Durham, North Carolina, USA
- Department of NeurologyDuke University Medical Center, Research Drive, Durham, North Carolina, USA
| | - Derek LeRoith
- Division of EndocrinologyDiabetes and Bone Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Emily Jane Gallagher
- Division of EndocrinologyDiabetes and Bone Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, USA
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73
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Yuan X, Zhang T, Zheng X, Zhang Y, Feng T, Liu P, Sun Z, Qin S, Liu X, Zhang L, Song J, Liu Y. Overexpression of SET oncoprotein is associated with tumor progression and poor prognosis in human gastric cancer. Oncol Rep 2017; 38:1733-1741. [PMID: 28677734 DOI: 10.3892/or.2017.5788] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 06/22/2017] [Indexed: 11/05/2022] Open
Abstract
SE translocation (SET) oncoprotein, an inhibitor of protein phosphatase 2A, is abnormally expressed in many cancers. In this study, SET was aberrantly upregulated in gastric cancer (GC) compared with control tissues. Clinicopathological analysis showed that SET expression was significantly correlated with pathological grade (p=0.002), lymph node stage (p=0.014), and invasive depth (p=0.022). Kaplan-Meier analysis indicated that patients with high SET expression showed poorer overall survival rates than those with low SET expression. Moreover, SET knockdown downregulated GC cell proliferation, colony formation, tumorigenesis, and metastasis. The biological effect of SET on proliferation and invasion was mediated by inhibition of protein phosphatase 2, which in turn, activated Akt. Taken together, our results suggested that SET overexpression is associated with GC progression, and it might be a potential diagnostic marker for GC, thereby a possible target for GC drug development.
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Affiliation(s)
- Xiaoning Yuan
- Laboratory of Molecular Target Therapy of Cancer, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Te Zhang
- Laboratory of Molecular Target Therapy of Cancer, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Xin Zheng
- Department of Gastrointestinal Surgery, Dongfeng General Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Yunfei Zhang
- Laboratory of Molecular Target Therapy of Cancer, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Tingting Feng
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Pengfei Liu
- Laboratory of Molecular Target Therapy of Cancer, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Zhiting Sun
- Laboratory of Molecular Target Therapy of Cancer, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Shanshan Qin
- Laboratory of Molecular Target Therapy of Cancer, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Xuewen Liu
- Laboratory of Molecular Target Therapy of Cancer, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Liang Zhang
- Laboratory of Molecular Target Therapy of Cancer, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Jie Song
- Department of Gastrointestinal Surgery, Dongfeng General Hospital, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Ying Liu
- Laboratory of Molecular Target Therapy of Cancer, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
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74
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Hung MH, Chen KF. Reprogramming the oncogenic response: SET protein as a potential therapeutic target in cancer. Expert Opin Ther Targets 2017; 21:685-694. [DOI: 10.1080/14728222.2017.1336226] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Man-Hsin Hung
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Kuen-Feng Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
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75
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Chung V, Mansfield AS, Braiteh F, Richards D, Durivage H, Ungerleider RS, Johnson F, Kovach JS. Safety, Tolerability, and Preliminary Activity of LB-100, an Inhibitor of Protein Phosphatase 2A, in Patients with Relapsed Solid Tumors: An Open-Label, Dose Escalation, First-in-Human, Phase I Trial. Clin Cancer Res 2016; 23:3277-3284. [PMID: 28039265 DOI: 10.1158/1078-0432.ccr-16-2299] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Revised: 11/30/2016] [Accepted: 12/05/2016] [Indexed: 11/16/2022]
Abstract
Purpose: To determine the MTD and to assess the safety, tolerability, and potential activity of LB-100, a first-in-class small-molecule inhibitor of protein phosphatase 2A (PP2A) in adult patients with progressive solid tumors.Experimental Design: LB-100 was administered intravenously daily for 3 days in 21-day cycles in a 3 + 3 dose escalation design.Results: There were 29 patient entries over 7 dose escalations. One patient stopped treatment after one dose because of an acute infection and was reenrolled after recovery; each course was analyzed as a separate patient entry. Two patients had dose-limiting toxicity (reversible increases in serum creatinine or calculated serum creatinine clearance) at the 3.1 mg/m2 level. Probable or possible study drug-related grade 3 adverse events occurred in 6 (20.7%) patients [anemia (n = 2), decreased creatinine clearance, dyspnea, hyponatremia, and lymphopenia]. Ten (50%) of 20 response-evaluable patients had stable disease for four or more cycles. One patient with pancreatic adenocarcinoma had a partial response noted after 10 cycles, which was maintained for five additional cycles. The other patients achieving stable disease had one of the following: fibrosarcoma, chondrosarcoma, thymoma, atypical carcinoid of lung, or ovarian, testicular, breast (n = 2), and prostate cancer. The recommended phase II dose of LB-100 is 2.33 mg/m2 daily for 3 days every 3 weeks.Conclusions: The safety, tolerability, preliminary evidence of antitumor activity, and novel mechanism of action of LB-100 support its continued development alone and in combination with other therapies. Clin Cancer Res; 23(13); 3277-84. ©2016 AACR.
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Affiliation(s)
| | | | - Fadi Braiteh
- Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada.,US Oncology Research, The Woodlands, Texas
| | - Donald Richards
- US Oncology Research, The Woodlands, Texas.,Texas Oncology, Tyler, Texas
| | | | | | | | - John S Kovach
- Lixte Biotechnology Holdings, Inc., East Setauket, New York.
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76
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Zhang W, Zheng X, Meng T, You H, Dong Y, Xing J, Chen S. SET protein overexpression contributes to paclitaxel resistance in MCF-7/S cells through PI3K/Akt pathway. J Drug Target 2016; 25:255-263. [PMID: 27718638 DOI: 10.1080/1061186x.2016.1245307] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Weipeng Zhang
- Department of Pharmacy, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
- Department of Pharmacy, The Eighth Hospital of Xi’an, Xi’an, PR China
| | - Xiaowei Zheng
- Department of Pharmacy, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Ti Meng
- Department of Pharmacy, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Haisheng You
- Department of Pharmacy, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Yalin Dong
- Department of Pharmacy, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
| | - Jianfeng Xing
- School of Pharmacy, Xi’an Jiaotong University, Xi’an, PR China
| | - Siying Chen
- Department of Pharmacy, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, PR China
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77
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Cayssials E, Guilhot F. Beyond tyrosine kinase inhibitors: Combinations and other agents. Best Pract Res Clin Haematol 2016; 29:271-283. [PMID: 27839568 DOI: 10.1016/j.beha.2016.10.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 10/10/2016] [Indexed: 12/17/2022]
Abstract
The modern therapeutic strategy for patients with chronic myeloid leukemia (CML) has been successfully altered by first and subsequently second generation tyrosine kinase inhibitors. However, despite high rate of molecular response, minimal residual disease persists in the majority of patients. Thus other approaches are warranted in order to eliminate the leukemia stem cells. Targeting CML stem cells could be of clinical benefit and a number of new agents are currently tested in phase I/II trials. Also immunological approaches with vaccination strategies and combination of tyrosine kinase inhibitors with various form of interferons are actively ongoing.
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78
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MYC-dependent recruitment of RUNX1 and GATA2 on the SET oncogene promoter enhances PP2A inactivation in acute myeloid leukemia. Oncotarget 2016; 8:53989-54003. [PMID: 28903318 PMCID: PMC5589557 DOI: 10.18632/oncotarget.9840] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/22/2016] [Indexed: 01/15/2023] Open
Abstract
The SET (I2PP2A) oncoprotein is a potent inhibitor of protein phosphatase 2A (PP2A) that regulates many cell processes and important signaling pathways. Despite the importance of SET overexpression and its prognostic impact in both hematologic and solid tumors, little is known about the mechanisms involved in its transcriptional regulation. In this report, we define the minimal promoter region of the SET gene, and identify a novel multi-protein transcription complex, composed of MYC, SP1, RUNX1 and GATA2, which activates SET expression in AML. The role of MYC is crucial, since it increases the expression of the other three transcription factors of the complex, and supports their recruitment to the promoter of SET. These data shed light on a new regulatory mechanism in cancer, in addition to the already known PP2A-MYC and SET-PP2A. Besides, we show that there is a significant positive correlation between the expression of SET and MYC, RUNX1, and GATA2 in AML patients, which further endorses our results. Altogether, this study opens new directions for understanding the mechanisms that lead to SET overexpression, and demonstrates that MYC, SP1, RUNX1 and GATA2 are key transcriptional regulators of SET expression in AML.
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79
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Cristóbal I, Madoz-Gúrpide J, Manso R, González-Alonso P, Rojo F, García-Foncillas J. Potential anti-tumor effects of FTY720 associated with PP2A activation: a brief review. Curr Med Res Opin 2016; 32:1137-41. [PMID: 26950691 DOI: 10.1185/03007995.2016.1162774] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
FTY720 (Fingolimod, Gilenya (†) ) is an FDA-approved immunosuppressant currently used in the treatment of multiple sclerosis. However, a large number of studies over the last few years have shown that FTY720 shows potent antitumor properties that suggest its potential usefulness as a novel anticancer agent. Interestingly, the restoration of protein phosphatase 2A (PP2A) activity mediated by FTY720 could play a key role in its antitumor effects. Taking into account that PP2A inactivation is a common event that determines poor outcome in several tumor types, FTY720 could serve as an alternative therapeutic strategy for cancer patients with such alterations.
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Affiliation(s)
- Ion Cristóbal
- a Translational Oncology Division , Oncohealth Institute, IIS-Fundacion Jimenez Diaz-UAM, University Hospital 'Fundacion Jimenez Diaz' , Madrid , Spain
| | | | - Rebeca Manso
- b Pathology Department , IIS 'Fundacion Jimenez Diaz' , Madrid , Spain
| | | | - Federico Rojo
- b Pathology Department , IIS 'Fundacion Jimenez Diaz' , Madrid , Spain
| | - Jesús García-Foncillas
- a Translational Oncology Division , Oncohealth Institute, IIS-Fundacion Jimenez Diaz-UAM, University Hospital 'Fundacion Jimenez Diaz' , Madrid , Spain
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80
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Arriazu E, Pippa R, Odero MD. Protein Phosphatase 2A as a Therapeutic Target in Acute Myeloid Leukemia. Front Oncol 2016; 6:78. [PMID: 27092295 PMCID: PMC4822158 DOI: 10.3389/fonc.2016.00078] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/21/2016] [Indexed: 12/31/2022] Open
Abstract
Acute myeloid leukemia (AML) is a heterogeneous malignant disorder of hematopoietic progenitor cells in which several genetic and epigenetic aberrations have been described. Despite progressive advances in our understanding of the molecular biology of this disease, the outcome for most patients is poor. It is, therefore, necessary to develop more effective treatment strategies. Genetic aberrations affecting kinases have been widely studied in AML; however, the role of phosphatases remains underexplored. Inactivation of the tumor-suppressor protein phosphatase 2A (PP2A) is frequent in AML patients, making it a promising target for therapy. There are several PP2A inactivating mechanisms reported in this disease. Deregulation or specific post-translational modifications of PP2A subunits have been identified as a cause of PP2A malfunction, which lead to deregulation of proliferation or apoptosis pathways, depending on the subunit affected. Likewise, overexpression of either SET or cancerous inhibitor of protein phosphatase 2A, endogenous inhibitors of PP2A, is a recurrent event in AML that impairs PP2A activity, contributing to leukemogenesis progression. Interestingly, the anticancer activity of several PP2A-activating drugs (PADs) depends on interaction/sequestration of SET. Preclinical studies show that pharmacological restoration of PP2A activity by PADs effectively antagonizes leukemogenesis, and that these drugs have synergistic cytotoxic effects with conventional chemotherapy and kinase inhibitors, opening new possibilities for personalized treatment in AML patients, especially in cases with SET-dependent inactivation of PP2A. Here, we review the role of PP2A as a druggable tumor suppressor in AML.
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Affiliation(s)
- Elena Arriazu
- Hematology/Oncology Program, Center for Applied Medical Research (CIMA), University of Navarra , Pamplona , Spain
| | - Raffaella Pippa
- Centre for Gene Regulation and Expression, University of Dundee , Dundee , UK
| | - María D Odero
- Hematology/Oncology Program, Center for Applied Medical Research (CIMA), University of Navarra, Pamplona, Spain; Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
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81
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Wang S, Xie W, Wang D, Peng Z, Zheng Y, Liu N, Dai W, Wang Y, Wang Z, Yang Y, Chen Y. Discovery of a small molecule targeting SET-PP2A interaction to overcome BCR-ABLT315I mutation of chronic myeloid leukemia. Oncotarget 2016; 6:12128-40. [PMID: 25900240 PMCID: PMC4494927 DOI: 10.18632/oncotarget.3665] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 03/02/2015] [Indexed: 01/05/2023] Open
Abstract
Despite the great success in using tyrosine kinase inhibitors (TKIs) to treat chronic myeloid leukemia (CML), the frequent development of multi-drug resistance, particularly the T315I mutation of BCR-ABL, remains a challenging issue. Enhancement of protein phosphatase 2A (PP2A) activity by dissociating its endogenous inhibitor SET is an effective approach to combat TKI-based resistance. Here, we report the identification of a novel 2-phenyloxypyrimidine compound TGI1002 to specifically disrupt SET-PP2A interaction. By binding to SET, TGI1002 inhibits SET-PP2A interaction and increases PP2A activity. In addition, knocking-down SET expression decreases tumor cell sensitivity to TGI1002. TGI1002 treatments also markedly increase dephosphorylation of BCR-ABL. Moreover, TGI1002 significantly inhibits tumor growth and prolongs survival of xenografted mice implanted with BaF3-p210T315I cells. These findings demonstrate that TGI1002 is a novel SET inhibitor with important therapeutic potential for the treatment of drug-resistant CML.
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Affiliation(s)
- Shuzhen Wang
- State Key Laboratory of Natural Medicines and Laboratory of Chemical Biology, China Pharmaceutical University, Nanjing, China
| | - Weiquan Xie
- State Key Laboratory of Natural Medicines and Laboratory of Chemical Biology, China Pharmaceutical University, Nanjing, China
| | - Duowei Wang
- State Key Laboratory of Natural Medicines and Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, China
| | - Zhigang Peng
- State Key Laboratory of Natural Medicines and Laboratory of Chemical Biology, China Pharmaceutical University, Nanjing, China
| | - Yan Zheng
- State Key Laboratory of Natural Medicines and Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, China
| | - Nan Liu
- State Key Laboratory of Natural Medicines and Laboratory of Chemical Biology, China Pharmaceutical University, Nanjing, China
| | - Wen Dai
- State Key Laboratory of Natural Medicines and Laboratory of Chemical Biology, China Pharmaceutical University, Nanjing, China
| | - Yang Wang
- State Key Laboratory of Natural Medicines and Laboratory of Chemical Biology, China Pharmaceutical University, Nanjing, China
| | - Zongqiang Wang
- State Key Laboratory of Natural Medicines and Laboratory of Chemical Biology, China Pharmaceutical University, Nanjing, China
| | - Yong Yang
- State Key Laboratory of Natural Medicines and Institute of Pharmaceutical Science, China Pharmaceutical University, Nanjing, China
| | - Yijun Chen
- State Key Laboratory of Natural Medicines and Laboratory of Chemical Biology, China Pharmaceutical University, Nanjing, China
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82
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Sangodkar J, Farrington C, McClinch K, Galsky MD, Kastrinsky DB, Narla G. All roads lead to PP2A: exploiting the therapeutic potential of this phosphatase. FEBS J 2016; 283:1004-24. [PMID: 26507691 PMCID: PMC4803620 DOI: 10.1111/febs.13573] [Citation(s) in RCA: 230] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/29/2015] [Accepted: 10/21/2015] [Indexed: 12/22/2022]
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase involved in the regulation of many cellular processes. A confirmed tumor suppressor protein, PP2A is genetically altered or functionally inactivated in many cancers highlighting a need for its therapeutic reactivation. In this review we discuss recent literature on PP2A: the elucidation of its structure and the functions of its subunits, and the identification of molecular lesions and post-translational modifications leading to its dysregulation in cancer. A final section will discuss the proteins and small molecules that modulate PP2A and how these might be used to target dysregulated forms of PP2A to treat cancers and other diseases.
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Affiliation(s)
- Jaya Sangodkar
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mt. Sinai, New York, NY, USA
| | - Caroline Farrington
- Department of Medicine and Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Kimberly McClinch
- Department of Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Matthew D. Galsky
- Department of Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - David B. Kastrinsky
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Goutham Narla
- Department of Medicine and Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, OH, USA
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83
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Hung MH, Chen YL, Chu PY, Shih CT, Yu HC, Tai WT, Shiau CW, Chen KF. Upregulation of the oncoprotein SET determines poor clinical outcomes in hepatocellular carcinoma and shows therapeutic potential. Oncogene 2016; 35:4891-902. [DOI: 10.1038/onc.2016.21] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 12/08/2015] [Accepted: 12/29/2015] [Indexed: 12/18/2022]
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84
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Ottenlinger F, Schwiebs A, Pfarr K, Wagner A, Grüner S, Mayer CA, Pfeilschifter JM, Radeke HH. Fingolimod targeting protein phosphatase 2A differently affects IL-33 induced IL-2 and IFN-γ production in CD8(+) lymphocytes. Eur J Immunol 2016; 46:941-51. [PMID: 26683421 DOI: 10.1002/eji.201545805] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 11/02/2015] [Accepted: 12/10/2015] [Indexed: 01/05/2023]
Abstract
Multiple sclerosis patients are treated with fingolimod (FTY720), a prodrug that acts as an immune modulator. FTY720 is first phosphorylated to FTY720-P and then internalizes sphingosine-1-phosphate receptors, preventing lymphocyte sequestration. IL-33 is released from necrotic endothelial cells and contributes to MS severity by coactivating T cells. Herein we analyzed the influence of FTY720, FTY720-P, and S1P on IL-33 induced formation of IL-2 and IFN-γ, by using IL-33 receptor overexpressing EL4 cells, primary CD8(+) T cells, and splenocytes. EL4-ST2 cells released IL-2 after IL-33 stimulation that was inhibited dose-dependently by FTY720-P but not FTY720. In this system, S1P increased IL-2, and accordingly, inhibition of S1P producing sphingosine kinases diminished IL-2 release. In primary CD8(+) T cells and splenocytes IL-33/IL-12 stimulation induced IFN-γ, which was prevented by FTY720 but not FTY720-P, independently from intracellular phosphorylation. The inhibition of IFN-γ by nonphosphorylated FTY720 was mediated via the SET/protein phosphatase 2A (PP2A) pathway, since a SET peptide antagonist also prevented IFN-γ formation and the inhibition of IFN-γ by FTY720 was reversible by a PP2A inhibitor. While our findings directly improve the understanding of FTY720 therapy in MS, they could also contribute to side effects of FTY720 treatment, like progressive multifocal leukoencephalopathy, caused by an insufficient immune response to a viral infection.
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Affiliation(s)
- Florian Ottenlinger
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Anja Schwiebs
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Kathrin Pfarr
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Annika Wagner
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Sophia Grüner
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Christoph A Mayer
- Center for Neurology and Neurosurgery, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Josef M Pfeilschifter
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
| | - Heinfried H Radeke
- pharmazentrum frankfurt/ZAFES, Hospital of the Goethe University, Frankfurt am Main, Germany
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85
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Hung MH, Wang CY, Chen YL, Chu PY, Hsiao YJ, Tai WT, Chao TT, Yu HC, Shiau CW, Chen KF. SET antagonist enhances the chemosensitivity of non-small cell lung cancer cells by reactivating protein phosphatase 2A. Oncotarget 2016; 7:638-55. [PMID: 26575017 PMCID: PMC4808023 DOI: 10.18632/oncotarget.6313] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 10/30/2015] [Indexed: 12/12/2022] Open
Abstract
SET is known as a potent PP2A inhibitor, however, its oncogenic role including its tumorigenic potential and involvement in the development of chemoresistance in non-small cell lung cancer (NSCLC) has not yet been fully discussed. In present study, we investigated the oncogenic role of SET by SET-knockdown and showed that SET silencing impaired cell growth rate, colony formation and tumor sphere formation in A549 cells. Notably, silencing SET enhanced the pro-apoptotic effects of paclitaxel, while ectopic expression of SET diminished the sensitivity of NSCLC cells to paclitaxel. Since the SET protein was shown to affect chemosensitivity, we next examined whether combining a novel SET antagonist, EMQA, sensitized NSCLC cells to paclitaxel. Both the in vitro and in vivo experiments suggested that EMQA and paclitaxel combination treatment was synergistic. Importantly, we found that downregulating p-Akt by inhibiting SET-mediated protein phosphatase 2A (PP2A) inactivation determined the pro-apoptotic effects of EMQA and paclitaxel combination treatment. To dissect the critical site for EMQA functioning, we generated several truncated SET proteins. By analysis of the effects of EMQA on the binding affinities of different truncated SET proteins to PP2A-catalytic subunits, we revealed that the 227-277 amino-acid sequence is critical for EMQA-induced SET inhibition. Our findings demonstrate the critical role of SET in NSCLC, particularly in the development of chemoresistance. The synergistic effects of paclitaxel and the SET antagonist shown in current study encourage further validation of the clinical potential of this combination.
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Affiliation(s)
- Man-Hsin Hung
- Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taipei City, Taiwan
- Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taipei City, Taiwan
- Program in Molecular Medicine, School of Life Science, National Yang-Ming University, Taipei City, Taiwan
- School of Medicine, National Yang-Ming University, Taipei City, Taiwan
| | - Cheng-Yi Wang
- Medical Research Center, Cardinal Tien Hospital, Fu Jen Catholic University, New Taipei, Taiwan
| | - Yen-Lin Chen
- Department of Pathology, Cardinal Tien Hospital, Fu Jen Catholic University, New Taipei, Taiwan
| | - Pei-Yi Chu
- Department of Pathology, Show Chwan Memorial Hospital, Changhua City, Taiwan
| | - Yung-Jen Hsiao
- Department of Medical Research, National Taiwan University Hospital, Zhongzheng District, Taiwan
| | - Wei-Tien Tai
- Department of Medical Research, National Taiwan University Hospital, Zhongzheng District, Taiwan
- National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Zhongzheng District, Taiwan
| | - Ting-Ting Chao
- Medical Research Center, Cardinal Tien Hospital, Fu Jen Catholic University, New Taipei, Taiwan
| | - Hui-Chuan Yu
- Department of Medical Research, National Taiwan University Hospital, Zhongzheng District, Taiwan
| | - Chung-Wai Shiau
- Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei City, Taiwan
| | - Kuen-Feng Chen
- Department of Medical Research, National Taiwan University Hospital, Zhongzheng District, Taiwan
- National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Zhongzheng District, Taiwan
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86
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Zhang W, Zheng X, Meng T, You H, Dong Y, Xing J, Chen S. HDACI regulates the PI3K/Akt signaling pathway to reverse MCF-7/PTX resistance by inhibiting SET. RSC Adv 2016. [DOI: 10.1039/c6ra06423j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The occurrence of chemoresistance greatly restricts the efficacy of antitumor drugs, and so novel agents are urgently needed to abrogate resistant phenotypes.
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Affiliation(s)
- Weipeng Zhang
- Department of Pharmacy
- The First Affiliated Hospital of Xi'an Jiaotong University
- Xi'an
- PR China
- Department of Pharmacy
| | - Xiaowei Zheng
- Department of Pharmacy
- The First Affiliated Hospital of Xi'an Jiaotong University
- Xi'an
- PR China
| | - Ti Meng
- Department of Pharmacy
- The First Affiliated Hospital of Xi'an Jiaotong University
- Xi'an
- PR China
| | - Haisheng You
- Department of Pharmacy
- The First Affiliated Hospital of Xi'an Jiaotong University
- Xi'an
- PR China
| | - Yalin Dong
- Department of Pharmacy
- The First Affiliated Hospital of Xi'an Jiaotong University
- Xi'an
- PR China
| | - Jianfeng Xing
- School of Pharmacy
- Xi'an Jiaotong University
- Xi'an
- PR China
| | - Siying Chen
- Department of Pharmacy
- The First Affiliated Hospital of Xi'an Jiaotong University
- Xi'an
- PR China
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87
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Hu X, Garcia C, Fazli L, Gleave M, Vitek MP, Jansen M, Christensen D, Mulholland DJ. Inhibition of Pten deficient Castration Resistant Prostate Cancer by Targeting of the SET - PP2A Signaling axis. Sci Rep 2015; 5:15182. [PMID: 26563471 PMCID: PMC4643319 DOI: 10.1038/srep15182] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 09/15/2015] [Indexed: 11/11/2022] Open
Abstract
The PP2A signaling axis regulates multiple oncogenic drivers of castration resistant prostate cancer (CRPC). We show that targeting the endogenous PP2A regulator, SET (I2PP2A), is a viable strategy to inhibit prostate cancers that are resistant to androgen deprivation therapy. Our data is corroborated by analysis of prostate cancer patient cohorts showing significant elevation of SET transcripts. Tissue microarray analysis reveals that elevated SET expression correlates with clinical cancer grading, duration of neoadjuvant hormone therapy (NHT) and time to biochemical recurrence. Using prostate regeneration assays, we show that in vivo SET overexpression is sufficient to induce hyperplasia and prostatic intraepithelial neoplasia. Knockdown of SET induced significant reductions in tumorgenesis both in murine and human xenograft models. To further validate SET as a therapeutic target, we conducted in vitro and in vivo treatments using OP449 - a recently characterized PP2A-activating drug (PAD). OP449 elicits robust anti-cancer effects inhibiting growth in a panel of enzalutamide resistant prostate cancer cell lines. Using the Pten conditional deletion mouse model of prostate cancer, OP449 potently inhibited PI3K-Akt signaling and impeded CRPC progression. Collectively, our data supports a critical role for the SET-PP2A signaling axis in CRPC progression and hormone resistant disease.
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Affiliation(s)
- Xiaoyong Hu
- The 6th People's Hospital, Shanghai Jiaotong University, Shanghai, 200233, China.,Icahn School of Medicine, Mount Sinai Medical Center, New York, NY, 10029, USA
| | - Consuelo Garcia
- Icahn School of Medicine, Mount Sinai Medical Center, New York, NY, 10029, USA
| | - Ladan Fazli
- The Prostate Centre at Vancouver General Hospital Vancouver, British Columbia, Canada
| | - Martin Gleave
- The Prostate Centre at Vancouver General Hospital Vancouver, British Columbia, Canada
| | - Michael P Vitek
- Oncotide Pharmaceuticals, Research Triangle Park, NC, 27709, USA
| | - Marilyn Jansen
- Oncotide Pharmaceuticals, Research Triangle Park, NC, 27709, USA
| | - Dale Christensen
- Oncotide Pharmaceuticals, Research Triangle Park, NC, 27709, USA.,Division of Hematology, Duke University Medical Center, Durham, NC 27710, USA
| | - David J Mulholland
- Icahn School of Medicine, Mount Sinai Medical Center, New York, NY, 10029, USA
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88
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Abstract
Cancer, more than any other human disease, now has a surfeit of potential molecular targets poised for therapeutic exploitation. Currently, a number of attractive and validated cancer targets remain outside of the reach of pharmacological regulation. Some have been described as undruggable, at least by traditional strategies. In this article, we outline the basis for the undruggable moniker, propose a reclassification of these targets as undrugged, and highlight three general classes of this imposing group as exemplars with some attendant strategies currently being explored to reclassify them. Expanding the spectrum of disease-relevant targets to pharmacological manipulation is central to reducing cancer morbidity and mortality.
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Affiliation(s)
- John S Lazo
- Fiske Drug Discovery Laboratory, Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908-0735; ,
| | - Elizabeth R Sharlow
- Fiske Drug Discovery Laboratory, Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908-0735; ,
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89
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Lamba JK, Pounds S, Cao X, Crews KR, Cogle CR, Bhise N, Raimondi SC, Downing JR, Baker SD, Ribeiro RC, Rubnitz JE. Clinical significance of in vivo cytarabine-induced gene expression signature in AML. Leuk Lymphoma 2015; 57:909-20. [PMID: 26366682 DOI: 10.3109/10428194.2015.1086918] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Despite initial remission, ∼60-70% of adult and 30% of pediatric patients experience relapse or refractory AML. Studies so far have identified base line gene expression profiles of pathogenic and prognostic significance in AML; however, the extent of change in gene expression post-initiation of treatment has not been investigated. Exposure of leukemic cells to chemotherapeutic agents such as cytarabine, a mainstay of AML chemotherapy, can trigger adaptive response by influencing leukemic cell transcriptome and, hence, development of resistance or refractory disease. It is, however, challenging to perform such a study due to lack of availability of specimens post-drug treatment. The primary objective of this study was to identify in vivo cytarabine-induced changes in leukemia cell transcriptome and to evaluate their impact on clinical outcome. The results highlight genes relevant to cytarabine resistance and support the concept of targeting cytarabine-induced genes as a means of improving response.
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Affiliation(s)
- Jatinder K Lamba
- a Pharmacotherapy and Translational Research, University of Florida , Gainesville , FL , USA
| | - Stanley Pounds
- b Biostatistics, St Jude Children's Research Hospital , Memphis , TN , USA
| | - Xueyuan Cao
- b Biostatistics, St Jude Children's Research Hospital , Memphis , TN , USA
| | - Kristine R Crews
- c Pharmaceutical Sciences, St Jude Children's Research Hospital , Memphis , TN , USA
| | - Christopher R Cogle
- d Division of Hematology and Oncology, Department of Medicine , University of Florida , Gainesville , FL , USA
| | - Neha Bhise
- a Pharmacotherapy and Translational Research, University of Florida , Gainesville , FL , USA
| | - Susana C Raimondi
- e Pathology, St Jude Children's Research Hospital , Memphis , TN , USA , and
| | - James R Downing
- e Pathology, St Jude Children's Research Hospital , Memphis , TN , USA , and
| | - Sharyn D Baker
- c Pharmaceutical Sciences, St Jude Children's Research Hospital , Memphis , TN , USA
| | - Raul C Ribeiro
- f Oncology, St Jude Children's Research Hospital , Memphis , TN , USA
| | - Jeffrey E Rubnitz
- f Oncology, St Jude Children's Research Hospital , Memphis , TN , USA
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90
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Lyn sustains oncogenic signaling in chronic lymphocytic leukemia by strengthening SET-mediated inhibition of PP2A. Blood 2015; 125:3747-55. [DOI: 10.1182/blood-2014-12-619155] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 04/21/2015] [Indexed: 01/12/2023] Open
Abstract
Key Points
Cytosolic HSP90-bound Lyn mediates resistance to apoptosis by strengthening PP2A/SET interaction in CLL cells. FTY720-analogues antagonizing the PP2A/SET interaction and Lyn inhibitors may provide a therapeutic approach of CLL.
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91
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Tortorella SM, Hung A, Karagiannis TC. The implication of cancer progenitor cells and the role of epigenetics in the development of novel therapeutic strategies for chronic myeloid leukemia. Antioxid Redox Signal 2015; 22:1425-62. [PMID: 25366930 DOI: 10.1089/ars.2014.6096] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SIGNIFICANCE Chronic myeloid leukemia (CML) involves the malignant transformation of hematopoietic stem cells, defined largely by the Philadelphia chromosome and expression of the breakpoint cluster region-Abelson (BCR-ABL) oncoprotein. Pharmacological tyrosine kinase inhibitors (TKIs), including imatinib mesylate, have overcome limitations in conventional treatment for the improved clinical management of CML. RECENT ADVANCES Accumulated evidence has led to the identification of a subpopulation of quiescent leukemia progenitor cells with stem-like self renewal properties that may initiate leukemogenesis, which are also shown to be present in residual disease due to their insensitivity to tyrosine kinase inhibition. CRITICAL ISSUES The characterization of quiescent leukemia progenitor cells as a unique cell population in CML pathogenesis has become critical with the complete elucidation of mechanisms involved in their survival independent of BCR-ABL that is important in the development of novel anticancer strategies. Understanding of these functional pathways in CML progenitor cells will allow for their selective therapeutic targeting. In addition, disease pathogenesis and drug responsiveness is also thought to be modulated by epigenetic regulatory mechanisms such as DNA methylation, histone acetylation, and microRNA expression, with a capacity to control CML-associated gene transcription. FUTURE DIRECTIONS A number of compounds in combination with TKIs are under preclinical and clinical investigation to assess their synergistic potential in targeting leukemic progenitor cells and/or the epigenome in CML. Despite the collective promise, further research is required in order to refine understanding, and, ultimately, advance antileukemic therapeutic strategies.
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Affiliation(s)
- Stephanie M Tortorella
- 1 Epigenomic Medicine, Baker IDI Heart and Diabetes Institute, The Alfred Medical Research and Education Precinct , Melbourne, Australia
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92
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Leucine-rich repeat-containing protein 59 mediates nuclear import of cancerous inhibitor of PP2A in prostate cancer cells. Tumour Biol 2015; 36:6383-90. [PMID: 25833693 DOI: 10.1007/s13277-015-3326-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 03/12/2015] [Indexed: 10/23/2022] Open
Abstract
Using yeast two-hybrid analysis, we identified several novel protein interactions for the oncoprotein Cancerous Inhibitor of PP2A (CIP2A) and confirmed a subset of these interactions in human cancer cell lines. Analysis of the interaction in prostate carcinoma cells between CIP2A and leucine-rich repeat-containing protein 59 (LRRC59) suggests that CIP2A is translocated into the nucleus at G2/M through its association with LRRC59. Recent work by others has demonstrated that nuclear CIP2A disrupts mitotic checkpoints, which promotes deregulation of the cell cycle and increases cancerous phenotypes. Thus, we provide a novel therapeutic mechanism for inhibiting CIP2A function in cancerous cells via targeting the CIP2A-LRRC59 interaction.
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93
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Ciccone M, Calin GA, Perrotti D. From the Biology of PP2A to the PADs for Therapy of Hematologic Malignancies. Front Oncol 2015; 5:21. [PMID: 25763353 PMCID: PMC4329809 DOI: 10.3389/fonc.2015.00021] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 01/16/2015] [Indexed: 11/13/2022] Open
Abstract
Over the past decades, an emerging role of phosphatases in the pathogenesis of hematologic malignancies and solid tumors has been established. The tumor-suppressor protein phosphatase 2A (PP2A) belongs to the serine-threonine phosphatases family and accounts for the majority of serine-threonine phosphatase activity in eukaryotic cells. Numerous studies have shown that inhibition of PP2A expression and/or function may contribute to leukemogenesis in several hematological malignancies. Likewise, overexpression or aberrant expression of physiologic PP2A inhibitory molecules (e.g., SET and its associated SETBP1 and CIP2A) may turn off PP2A function and participate to leukemic progression. The discovery of PP2A as tumor suppressor has prompted the evaluation of the safety and the efficacy of new compounds, which can restore PP2A activity in leukemic cells. Although further studies are needed to better understand how PP2A acts in the intricate phosphatases/kinases cancer network, the results reviewed herein strongly support the development on new PP2A-activating drugs and the immediate introduction of those available into clinical protocols for leukemia patients refractory or resistant to current available therapies.
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Affiliation(s)
- Maria Ciccone
- Department of Experimental Therapeutics, MD Anderson Cancer Center, The University of Texas , Houston, TX , USA
| | - George A Calin
- Department of Experimental Therapeutics, MD Anderson Cancer Center, The University of Texas , Houston, TX , USA
| | - Danilo Perrotti
- Department of Medicine, The Greenebaum Cancer Center, University of Maryland School of Medicine , Baltimore, MD , USA
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94
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Ramaswamy K, Spitzer B, Kentsis A. Therapeutic Re-Activation of Protein Phosphatase 2A in Acute Myeloid Leukemia. Front Oncol 2015; 5:16. [PMID: 25699237 PMCID: PMC4313608 DOI: 10.3389/fonc.2015.00016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 01/13/2015] [Indexed: 11/13/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase that is required for normal cell growth and development. PP2A is a potent tumor suppressor, which is inactivated in cancer cells as a result of genetic deletions and mutations. In myeloid leukemias, genes encoding PP2A subunits are generally intact. Instead, PP2A is functionally inhibited by post-translational modifications of its catalytic C subunit, and interactions with negative regulators by its regulatory B and scaffold A subunits. Here, we review the molecular mechanisms of genetic and functional inactivation of PP2A in human cancers, with a particular focus on human acute myeloid leukemias (AML). By analyzing expression of genes encoding PP2A subunits using transcriptome sequencing, we find that PP2A dysregulation in AML is characterized by silencing and overexpression of distinct A scaffold and B regulatory subunits, respectively. We review the mechanisms of functional PP2A activation by drugs such as fingolimod, forskolin, OP449, and perphenazine. This analysis yields two non-mutually exclusive mechanisms for therapeutic PP2A re-activation: (i) allosteric activation of the phosphatase activity, and (ii) stabilization of active holo-enzyme assembly and displacement of negative regulatory factors from A and B subunits. Future studies should allow the development of specific and potent pharmacologic activators of PP2A, and definition of susceptible disease subsets based on specific mechanisms of PP2A dysregulation.
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Affiliation(s)
- Kavitha Ramaswamy
- Molecular Pharmacology and Chemistry Program, Department of Pediatrics, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, Weill Medical College of Cornell University , New York, NY , USA
| | - Barbara Spitzer
- Molecular Pharmacology and Chemistry Program, Department of Pediatrics, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, Weill Medical College of Cornell University , New York, NY , USA
| | - Alex Kentsis
- Molecular Pharmacology and Chemistry Program, Department of Pediatrics, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, Weill Medical College of Cornell University , New York, NY , USA
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95
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Barragán E, Chillón MC, Castelló-Cros R, Marcotegui N, Prieto MI, Hoyos M, Pippa R, Llop M, Etxabe A, Cervera J, Rodríguez G, Buño I, Rifón J, Sierra J, González M, Calasanz MJ, Sanz MA, Odero MD. CIP2A high expression is a poor prognostic factor in normal karyotype acute myeloid leukemia. Haematologica 2015; 100:e183-5. [PMID: 25637054 DOI: 10.3324/haematol.2014.118117] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Eva Barragán
- Clinical Laboratory and Department of Hematology, University Hospital La Fe, Valencia, Spain
| | - María Carmen Chillón
- Department of Hematology, University Hospital of Salamanca, Salamanca Institute for Biomedical Research (IBSAL), Spain
| | | | - Nerea Marcotegui
- Program of Hematology-Oncology, CIMA, University of Navarra, Pamplona, Spain
| | - María Isabel Prieto
- Department of Hematology, University Hospital of Salamanca, Salamanca Institute for Biomedical Research (IBSAL), Spain
| | - Montserrat Hoyos
- Department of Hematology, Hospital Santa Creu i Sant Pau, Barcelona, Spain
| | - Raffaella Pippa
- Program of Hematology-Oncology, CIMA, University of Navarra, Pamplona, Spain
| | - Marta Llop
- Clinical Laboratory and Department of Hematology, University Hospital La Fe, Valencia, Spain
| | - Amaia Etxabe
- Program of Hematology-Oncology, CIMA, University of Navarra, Pamplona, Spain
| | - José Cervera
- Clinical Laboratory and Department of Hematology, University Hospital La Fe, Valencia, Spain
| | - Gabriela Rodríguez
- Department of Hematology, Gregorio Marañón Institute for Health Research, Madrid, Spain
| | - Ismael Buño
- Department of Hematology, Gregorio Marañón Institute for Health Research, Madrid, Spain
| | - José Rifón
- Department of Hematology, Clinical University of Navarra, Pamplona, Spain
| | - Jorge Sierra
- Department of Hematology, Hospital Santa Creu i Sant Pau, Barcelona, Spain
| | - Marcos González
- Department of Hematology, University Hospital of Salamanca, Salamanca Institute for Biomedical Research (IBSAL), Spain
| | - María J Calasanz
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain
| | - Miguel A Sanz
- Clinical Laboratory and Department of Hematology, University Hospital La Fe, Valencia, Spain
| | - María D Odero
- Program of Hematology-Oncology, CIMA, University of Navarra, Pamplona, Spain Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain
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96
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Haesen D, Sents W, Lemaire K, Hoorne Y, Janssens V. The Basic Biology of PP2A in Hematologic Cells and Malignancies. Front Oncol 2014; 4:347. [PMID: 25566494 PMCID: PMC4263090 DOI: 10.3389/fonc.2014.00347] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 11/20/2014] [Indexed: 12/30/2022] Open
Abstract
Reversible protein phosphorylation plays a crucial role in regulating cell signaling. In normal cells, phosphoregulation is tightly controlled by a network of protein kinases counterbalanced by several protein phosphatases. Deregulation of this delicate balance is widely recognized as a central mechanism by which cells escape external and internal self-limiting signals, eventually resulting in malignant transformation. A large fraction of hematologic malignancies is characterized by constitutive or unrestrained activation of oncogenic kinases. This is in part achieved by activating mutations, chromosomal rearrangements, or constitutive activation of upstream kinase regulators, in part by inactivation of their anti-oncogenic phosphatase counterparts. Protein phosphatase 2A (PP2A) represents a large family of cellular serine/threonine phosphatases with suspected tumor suppressive functions. In this review, we highlight our current knowledge about the complex structure and biology of these phosphatases in hematologic cells, thereby providing the rationale behind their diverse signaling functions. Eventually, this basic knowledge is a key to truly understand the tumor suppressive role of PP2A in leukemogenesis and to allow further rational development of therapeutic strategies targeting PP2A.
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Affiliation(s)
- Dorien Haesen
- Laboratory of Protein Phosphorylation and Proteomics, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
| | - Ward Sents
- Laboratory of Protein Phosphorylation and Proteomics, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
| | - Katleen Lemaire
- Gene Expression Unit, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
| | - Yana Hoorne
- Laboratory of Protein Phosphorylation and Proteomics, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation and Proteomics, Department Cellular and Molecular Medicine, University of Leuven , Leuven , Belgium
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97
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Elo LL, Karjalainen R, Ohman T, Hintsanen P, Nyman TA, Heckman CA, Aittokallio T. Statistical detection of quantitative protein biomarkers provides insights into signaling networks deregulated in acute myeloid leukemia. Proteomics 2014; 14:2443-53. [PMID: 25211154 DOI: 10.1002/pmic.201300460] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 07/31/2014] [Accepted: 09/08/2014] [Indexed: 12/12/2022]
Abstract
The increasing coverage and sensitivity of LC-MS/MS-based proteomics have expanded its applications in systems medicine. In particular, label-free quantitation approaches are enabling biomarker discovery in terms of statistical comparison of proteomic profiles across large numbers of clinical samples. However, it still remains poorly understood how much protein markers can add novel insights compared to markers derived from mRNA transcriptomic profiling. Using paired label-free LC-MS/MS and gene expression microarray measurements from primary samples of patients with acute myeloid leukemia (AML), we demonstrate here that while the quantitative proteomic and transcriptomic profiles were highly correlated, in general, the marker panels showing statistically significant expression changes across the disease and healthy groups were profoundly different between protein and mRNA levels. In particular, the proteomic assay enabled unique links to known leukemic processes, which were missed when using the transcriptomic profiling alone, as well as identified additional links to metabolic regulators and chromatin remodelers, such as GPX1, fumarate hydratase, and SET oncogene, which have subsequently been evaluated in independent AML samples. Overall, these results highlighted the complementary and informative view obtained from the quantitative LC-MS/MS approach into the AML deregulated signaling networks.
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Affiliation(s)
- Laura L Elo
- Department of Mathematics and Statistics, University of Turku, Turku, Finland; Turku Centre for Biotechnology, Turku, Finland
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98
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Reilly PT, Yu Y, Hamiche A, Wang L. Cracking the ANP32 whips: important functions, unequal requirement, and hints at disease implications. Bioessays 2014; 36:1062-71. [PMID: 25156960 PMCID: PMC4270211 DOI: 10.1002/bies.201400058] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The acidic (leucine-rich) nuclear phosphoprotein 32 kDa (ANP32) family is composed of small, evolutionarily conserved proteins characterized by an N-terminal leucine-rich repeat domain and a C-terminal low-complexity acidic region. The mammalian family members (ANP32A, ANP32B, and ANP32E) are ascribed physiologically diverse functions including chromatin modification and remodelling, apoptotic caspase modulation, protein phosphatase inhibition, as well as regulation of intracellular transport. In addition to reviewing the widespread literature on the topic, we present a concept of the ANP32s as having a whip-like structure. We also present hypotheses that ANP32C and other intronless sequences should not currently be considered bona fide family members, that their disparate necessity in development may be due to compensatory mechanisms, that their contrasting roles in cancer are likely context-dependent, along with an underlying hypothesis that ANP32s represent an important node of physiological regulation by virtue of their diverse biochemical activities.
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Affiliation(s)
- Patrick T Reilly
- Laboratory of Inflammation Biology, National Cancer Centre Singapore, Singapore, Singapore
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99
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Liu H, Gu Y, Yin J, Zheng G, Wang C, Zhang Z, Deng M, Liu J, Jia X, He Z. SET-mediated NDRG1 inhibition is involved in acquisition of epithelial-to-mesenchymal transition phenotype and cisplatin resistance in human lung cancer cell. Cell Signal 2014; 26:2710-20. [PMID: 25152373 DOI: 10.1016/j.cellsig.2014.08.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 08/15/2014] [Indexed: 12/22/2022]
Abstract
Development of resistance to therapy continues to be a serious clinical problem in lung cancer management. Cancer cells undergoing epithelial-to-mesenchymal transition (EMT) have been shown to play roles in resistance to chemotherapy. Here, we utilized a proteomics-based method and identified a significant downregulation of the metastasis suppressor NDRG1 in drug resistant lung cancer cells. We showed that downregulation of DNRG1 constitutes a mechanism for acquisition of EMT phenotype and endows lung cancer cells with an increased resistance to cisplatin. We also identified a signal cascade, namely, SET--| PP2A--| c-myc--| NDRG1, in which upregulation of SET is critical for inhibition of NDRG1. We also found that blockade of SET (or reactivation of PP2A) by FTY720 reverted EMT, restored drug sensitivity, and inhibited invasiveness and growth of lung tumor xenografts. Together, our results indicated a functional link between SET-mediated NDRG1 regulation and acquisition of EMT phenotype and drug resistance, and provided an evidence that blockade of SET-driven EMT can overcome drug resistance and inhibit tumor progression.
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Affiliation(s)
- Hao Liu
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China
| | - Yixue Gu
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China
| | - Jiang Yin
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China
| | - Guopei Zheng
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China
| | - Chenkun Wang
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China
| | - Zhijie Zhang
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China
| | - Min Deng
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China
| | - Jifang Liu
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China
| | - Xiaoting Jia
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China
| | - Zhimin He
- Cancer Hospital and Cancer Research Institute, Guangzhou Medical University, Guangzhou, China.
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100
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Targeting c-MYC by antagonizing PP2A inhibitors in breast cancer. Proc Natl Acad Sci U S A 2014; 111:9157-62. [PMID: 24927563 DOI: 10.1073/pnas.1317630111] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The transcription factor c-MYC is stabilized and activated by phosphorylation at serine 62 (S62) in breast cancer. Protein phosphatase 2A (PP2A) is a critical negative regulator of c-MYC through its ability to dephosphorylate S62. By inactivating c-MYC and other key signaling pathways, PP2A plays an important tumor suppressor function. Two endogenous inhibitors of PP2A, I2PP2A, Inhibitor-2 of PP2A (SET oncoprotein) and cancerous inhibitor of PP2A (CIP2A), inactivate PP2A and are overexpressed in several tumor types. Here we show that SET is overexpressed in about 50-60% and CIP2A in about 90% of breast cancers. Knockdown of SET or CIP2A reduces the tumorigenic potential of breast cancer cell lines both in vitro and in vivo. Treatment of breast cancer cells in vitro or in vivo with OP449, a novel SET antagonist, also decreases the tumorigenic potential of breast cancer cells and induces apoptosis. We show that this is, at least in part, due to decreased S62 phosphorylation of c-MYC and reduced c-MYC activity and target gene expression. Because of the ubiquitous expression and tumor suppressor activity of PP2A in cells, as well as the critical role of c-MYC in human cancer, we propose that activation of PP2A (here accomplished through antagonizing endogenous inhibitors) could be a novel antitumor strategy to posttranslationally target c-MYC in breast cancer.
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