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Neale DA, Morris JC, Verrills NM, Ammit AJ. Understanding the regulatory landscape of protein phosphatase 2A (PP2A): Pharmacological modulators and potential therapeutics. Pharmacol Ther 2025; 269:108834. [PMID: 40023321 DOI: 10.1016/j.pharmthera.2025.108834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2024] [Revised: 01/20/2025] [Accepted: 02/20/2025] [Indexed: 03/04/2025]
Abstract
Protein phosphatase 2A (PP2A) is a ubiquitously expressed serine/threonine phosphatase with a diverse and integral role in cellular signalling pathways. Consequently, its dysfunction is frequently observed in disease states such as cancer, inflammation and Alzheimer's disease. A growing understanding of both PP2A and its endogenous regulatory proteins has presented numerous targets for therapeutic intervention. This provides important context for the dynamic control and dysregulation of PP2A function in disease states. Understanding the intricate regulation of PP2A signalling in disease has resulted in the development of novel pharmacological agents aimed at restoring cellular homeostasis. Herein we review the structure and function of PP2A together with pharmacological modulators, both endogenous (proteins) and exogenous (small molecules and peptides), with relevance to targeting PP2A as a future pharmacotherapeutic strategy.
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Affiliation(s)
- David A Neale
- School of Chemistry, UNSW Sydney, NSW 2052, Australia
| | | | - Nicole M Verrills
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, NSW 2308, Australia; Precision Medicine Program, Hunter Medical Research Institute, New Lambton, NSW 2305, Australia
| | - Alaina J Ammit
- Woolcock Emphysema Centre, Woolcock Institute of Medical Research, Macquarie University, NSW, Australia; School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW, Australia.
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2
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Yao H, Zhang M, Wang D. The next decade of SET: from an oncoprotein to beyond. J Mol Cell Biol 2024; 16:mjad082. [PMID: 38157418 PMCID: PMC11267991 DOI: 10.1093/jmcb/mjad082] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 11/22/2023] [Accepted: 12/24/2023] [Indexed: 01/03/2024] Open
Abstract
This year marks the fourth decade of research into the protein SET, which was discovered in 1992. SET was initially identified as an oncoprotein but later shown to be a multifaceted protein involved in regulating numerous biological processes under both physiological and pathophysiological conditions. SET dysfunction is closely associated with diseases, such as cancer and Alzheimer's disease. With the increasing understanding of how SET works and how it is regulated in cells, targeting aberrant SET has emerged as a potential strategy for disease intervention. In this review, we present a comprehensive overview of the advancements in SET studies, encompassing its biological functions, regulatory networks, clinical implications, and pharmacological inhibitors. Furthermore, we provide insights into the future prospects of SET research, with a particular emphasis on its promising potential in the realm of immune modulation.
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Affiliation(s)
- Han Yao
- State Key Laboratory of Common Mechanism Research for Major Diseases & Department of Medical Genetics, Institute of Basic Medical Sciences & School of Basic Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
| | - Meng Zhang
- State Key Laboratory of Common Mechanism Research for Major Diseases & Department of Medical Genetics, Institute of Basic Medical Sciences & School of Basic Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
| | - Donglai Wang
- State Key Laboratory of Common Mechanism Research for Major Diseases & Department of Medical Genetics, Institute of Basic Medical Sciences & School of Basic Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, China
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3
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Johnson H, Narayan S, Sharma AK. Altering phosphorylation in cancer through PP2A modifiers. Cancer Cell Int 2024; 24:11. [PMID: 38184584 PMCID: PMC10770906 DOI: 10.1186/s12935-023-03193-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 12/25/2023] [Indexed: 01/08/2024] Open
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase integral to the regulation of many cellular processes. Due to the deregulation of PP2A in cancer, many of these processes are turned toward promoting tumor progression. Considerable research has been undertaken to discover molecules capable of modulating PP2A activity in cancer. Because PP2A is capable of immense substrate specificity across many cellular processes, the therapeutic targeting of PP2A in cancer can be completed through either enzyme inhibitors or activators. PP2A modulators likewise tend to be effective in drug-resistant cancers and work synergistically with other known cancer therapeutics. In this review, we will discuss the patterns of PP2A deregulation in cancer, and its known downstream signaling pathways important for cancer regulation, along with many activators and inhibitors of PP2A known to inhibit cancer progression.
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Affiliation(s)
- Hannah Johnson
- Department of Pharmacology, Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Satya Narayan
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL, 32610, USA
| | - Arun K Sharma
- Department of Pharmacology, Penn State Cancer Institute, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA.
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4
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Clementi L, Sabetta S, Zelli V, Compagnoni C, Tessitore A, Mattei V, Angelucci A. Mitotic phosphorylation of Tau/MAPT modulates cell cycle progression in prostate cancer cells. J Cancer Res Clin Oncol 2023; 149:7689-7701. [PMID: 37000265 PMCID: PMC10374748 DOI: 10.1007/s00432-023-04721-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 03/22/2023] [Indexed: 04/01/2023]
Abstract
PURPOSE Tau/MAPT (microtubule associated protein tau) protein is actively studied for the pathologic consequences of its aberrant proteostasis in central nervous system leading to neurodegenerative diseases. Besides its ability to generate insoluble toxic oligomers, Tau homeostasis has attracted attention for its involvement in the formation of the mitotic spindle. This evidence, in association with the description of Tau expression in extra-neuronal tissues, and mainly in cancer tissues, constitutes the rationale for a more in-depth investigation of Tau role also in neoplastic diseases. METHODS In our study, we investigated the expression of phosphorylated Tau in prostate cancer cell lines with particular focus on the residue Thr231 present in microtubule binding domain. RESULTS The analysis of prostate cancer cells synchronized with nocodazole demonstrated that the expression of Tau protein phosphorylated at residue Thr231 is restricted to G2/M cell cycle phase. The phosphorylated form was unable to bind tubulin and it does not localize on mitotic spindle. As demonstrated by the use of specific inhibitors, the phosphorylation status of Tau is under the direct control of cdk5 and PP2A, while cdk1 activation was able to exert an indirect control. These mechanisms were also active in cells treated with docetaxel, where counteracting the expression of the dephosphorylated form, by kinase inhibition or protein silencing, determined resistance to drug toxicity. CONCLUSIONS We hypothesize that phosphorylation status of Tau is a key marker for G2/M phase in prostate cancer cells and that the forced modulation of Tau phosphorylation can interfere with the capacity of cell to efficiently progress through G2/M phase.
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Affiliation(s)
- Letizia Clementi
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio, 67100, L'Aquila, Italy
| | - Samantha Sabetta
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio, 67100, L'Aquila, Italy
| | - Veronica Zelli
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio, 67100, L'Aquila, Italy
- Center for Molecular Diagnostics and Advanced Therapies, University of L'Aquila, 67100, L'Aquila, Italy
| | - Chiara Compagnoni
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio, 67100, L'Aquila, Italy
| | - Alessandra Tessitore
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio, 67100, L'Aquila, Italy
- Center for Molecular Diagnostics and Advanced Therapies, University of L'Aquila, 67100, L'Aquila, Italy
| | - Vincenzo Mattei
- Biomedicine and Advanced Technologies Rieti Center "Sabina Universitas", 02100, Rieti, Italy
| | - Adriano Angelucci
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, Via Vetoio, 67100, L'Aquila, Italy.
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5
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Kashani E, Vassella E. Pleiotropy of PP2A Phosphatases in Cancer with a Focus on Glioblastoma IDH Wildtype. Cancers (Basel) 2022; 14:5227. [PMID: 36358647 PMCID: PMC9654311 DOI: 10.3390/cancers14215227] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/13/2022] [Accepted: 10/20/2022] [Indexed: 07/29/2023] Open
Abstract
Serine/Threonine protein phosphatase 2A (PP2A) is a heterotrimeric (or occasionally, heterodimeric) phosphatase with pleiotropic functions and ubiquitous expression. Despite the fact that they all contribute to protein dephosphorylation, multiple PP2A complexes exist which differ considerably by their subcellular localization and their substrate specificity, suggesting diverse PP2A functions. PP2A complex formation is tightly regulated by means of gene expression regulation by transcription factors, microRNAs, and post-translational modifications. Furthermore, a constant competition between PP2A regulatory subunits is taking place dynamically and depending on the spatiotemporal circumstance; many of the integral subunits can outcompete the rest, subjecting them to proteolysis. PP2A modulation is especially important in the context of brain tumors due to its ability to modulate distinct glioma-promoting signal transduction pathways, such as PI3K/Akt, Wnt, Ras, NF-κb, etc. Furthermore, PP2A is also implicated in DNA repair and survival pathways that are activated upon treatment of glioma cells with chemo-radiation. Depending on the cancer cell type, preclinical studies have shown some promise in utilising PP2A activator or PP2A inhibitors to overcome therapy resistance. This review has a special focus on "glioblastoma, IDH wild-type" (GBM) tumors, for which the therapy options have limited efficacy, and tumor relapse is inevitable.
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Affiliation(s)
- Elham Kashani
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Erik Vassella
- Institute of Pathology, University of Bern, 3008 Bern, Switzerland
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6
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Galiger C, Dahlhaus M, Vitek MP, Debatin KM, Beltinger C. PPP2CA Is a Novel Therapeutic Target in Neuroblastoma Cells That Can Be Activated by the SET Inhibitor OP449. Front Oncol 2022; 12:744984. [PMID: 35814385 PMCID: PMC9258974 DOI: 10.3389/fonc.2022.744984] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 05/11/2022] [Indexed: 11/13/2022] Open
Abstract
Neuroblastoma (NB) is the most common extracranial solid tumor in childhood and has a poor prognosis in high-risk cases, requiring novel therapies. Pathways that depend on phospho-signaling maintain the aggressiveness of NB. Protein phosphatase 2 (PP2A) with its catalytic subunit PPP2CA is a major phosphatase in cancer cells, including NB. We show that reduction of PPP2CA by knock-down decreased growth of NB cells and that complete ablation of PPP2CA by knock-out was not tolerated. Thus, NB cells are addicted to PPP2CA, an addiction augmented by MYCN activation. SET, a crucial endogenous inhibitor of PP2A, was overexpressed in poor-prognosis NB. The SET inhibitor OP449 effectively decreased the viability of NB cells, independent of their molecular alterations and in line with a tumor suppressor function of PPP2CA. The contrasting concentration-dependent functions of PPP2CA as an essential survival gene at low expression levels and a tumor suppressor at high levels are reminiscent of other genes showing this so-called Goldilocks phenomenon. PP2A reactivated by OP449 decreased activating phosphorylation of serine/threonine residues in the AKT pathway. Conversely, induced activation of AKT led to partial rescue of OP449-mediated viability inhibition. Dasatinib, a kinase inhibitor used in relapsed/refractory NB, and OP449 synergized, decreasing activating AKT phosphorylations. In summary, concomitantly reactivating phosphatases and inhibiting kinases with a combination of OP449 and dasatinib are promising novel therapeutic approaches to NB.
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Affiliation(s)
- Celimene Galiger
- Section of Experimental Pediatric Oncology, Department of Pediatrics and Adolescent Medicine, University Medical Center, Ulm, Germany
| | - Meike Dahlhaus
- Section of Experimental Pediatric Oncology, Department of Pediatrics and Adolescent Medicine, University Medical Center, Ulm, Germany
| | - Michael Peter Vitek
- Cognosci, Inc., Research Triangle Park, NC, United States
- Department of Neurology, Duke University Medical Center, Durham, NC, United States
| | - Klaus-Michael Debatin
- Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Christian Beltinger
- Section of Experimental Pediatric Oncology, Department of Pediatrics and Adolescent Medicine, University Medical Center, Ulm, Germany
- Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
- *Correspondence: Christian Beltinger,
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7
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Kohyanagi N, Kitamura N, Tanaka K, Mizuno T, Fujiwara N, Ohama T, Sato K. The protein level of the tumor-promoting factor SET is regulated by cell density. J Biochem 2022; 171:295-303. [PMID: 35076073 DOI: 10.1093/jb/mvab125] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 11/15/2021] [Indexed: 11/14/2022] Open
Abstract
SET/I2PP2A is a multifunctional protein that acts as an intrinsic inhibitor of the tumor suppressor protein phosphatase 2A and as a histone chaperone. Increased SET levels have been observed in various cancers; however, the underlying molecular mechanisms remain unclear. In this study, we found that SET protein accumulates with the increasing density of cultured cells. This phenomenon was observed not only in cancer cell lines but also in non-cancer cell lines. The mRNA levels of SET were not affected by the cell density. Proteasome inhibition decreased SET levels, whereas autophagy inhibition led to SET accumulation, indicating the involvement of autophagy. The mRNA and protein expression of SETBP1, which stabilizes the SET protein, increased with cell density. The decrease in SET level due to the loss of SETBP1 was more pronounced in wild-type cells than that in autophagy-deficient cells. These results have revealed a mechanism underlying the regulation of SET level, wherein increased cell density induces SETBP1 expression and protects SET from autophagy.
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Affiliation(s)
- Naoki Kohyanagi
- Laboratory of Veterinary Pharmacology and Laboratory of Molecular Diagnostics
| | - Nao Kitamura
- Laboratory of Veterinary Pharmacology and Laboratory of Molecular Diagnostics
| | - Keiko Tanaka
- Laboratory of Veterinary Pharmacology and Laboratory of Molecular Diagnostics
| | - Takuya Mizuno
- Laboratory of Molecular Diagnostics and Therapeutics, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, 753-8515, Japan
| | - Nobuyuki Fujiwara
- Laboratory of Drug Discovery and Pharmacology, Faculty of Veterinary Medicine, Okayama University of Science, 794-8555 Ehime, Japan
| | - Takashi Ohama
- Laboratory of Veterinary Pharmacology and Laboratory of Molecular Diagnostics
| | - Koichi Sato
- Laboratory of Veterinary Pharmacology and Laboratory of Molecular Diagnostics
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8
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Cristóbal I, Santos A, Rubio J, Rojo F, García-Foncillas J. Comment on "miR-199b-5p-DDR1-ERK signalling axis suppresses prostate cancer metastasis via inhibiting epithelial-mesenchymal transition". Br J Cancer 2021; 125:618-619. [PMID: 34012034 PMCID: PMC8367958 DOI: 10.1038/s41416-021-01433-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/23/2021] [Accepted: 04/28/2021] [Indexed: 02/02/2023] Open
Affiliation(s)
- Ion Cristóbal
- grid.476442.7Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS-Fundación Jimenez Díaz-UAM, Madrid, Spain ,grid.419651.e0000 0000 9538 1950Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jimenez Díaz-UAM, Madrid, Spain
| | - Andrea Santos
- grid.476442.7Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS-Fundación Jimenez Díaz-UAM, Madrid, Spain ,grid.419651.e0000 0000 9538 1950Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jimenez Díaz-UAM, Madrid, Spain
| | - Jaime Rubio
- grid.476442.7Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS-Fundación Jimenez Díaz-UAM, Madrid, Spain ,grid.419651.e0000 0000 9538 1950Medical Oncology Department, University Hospital “Fundacion Jimenez Diaz”, Madrid, Spain
| | - Federico Rojo
- grid.419651.e0000 0000 9538 1950Pathology Department, IIS-Fundación Jiménez Díaz-UAM, Madrid, Spain
| | - Jesús García-Foncillas
- grid.419651.e0000 0000 9538 1950Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jimenez Díaz-UAM, Madrid, Spain ,grid.419651.e0000 0000 9538 1950Medical Oncology Department, University Hospital “Fundacion Jimenez Diaz”, Madrid, Spain
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9
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Dacol EC, Wang S, Chen Y, Lepique AP. The interaction of SET and protein phosphatase 2A as target for cancer therapy. Biochim Biophys Acta Rev Cancer 2021; 1876:188578. [PMID: 34116173 DOI: 10.1016/j.bbcan.2021.188578] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/31/2021] [Accepted: 05/31/2021] [Indexed: 11/16/2022]
Abstract
In cancer cells, tumor suppressor proteins loss-of-function are usually the result of genetic mutations. Protein Phosphatase 2A is a tumor suppressor that inactivates several signaling pathways through removal of phosphate residues important for other proteins stability and/or activation. Different from other tumor suppressors, PP2A is, in many cancer types, inactivated by endogenous inhibitors. In physiological conditions, these inhibitors are important to balance PP2A activity. However, in cancer cells, overexpression of these inhibitors can keep PP2A inactive, resulting in sustained activation of mitogenic signaling pathways and transcription factors, metabolic reprogramming, with the resulting cancer progression and the resistance to anti-cancer therapies. One of these endogenous inhibitors is the protein SET (SE Translocation). SET is a multifunctional protein, which high expression has been associated with several types of cancer, as well as other diseases such as Alzheimer's disease. Disruption of the interaction between SET and PP2A to rescue the activity of PP2A may represent a new therapeutic strategy and opportunity for cancer treatment. This review brings up-to-date advances on the interactions between SET and PP2A and their biological consequences. Moreover, we review reported inhibitors of SET-PP2A interaction under investigation as therapeutic opportunities for the treatment of cancers.
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Affiliation(s)
- E C Dacol
- Department of Immunology, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av.Prof. Lineu Prestes, 1730, room 136, Biomedicas IV Building, São Paulo CEP 05508-000, SP, Brazil
| | - S Wang
- Laboratory of Chemical Biology, China Pharmaceutical University, 639 Longmian Avenue, Nanjing 211198, China
| | - Y Chen
- Laboratory of Chemical Biology, China Pharmaceutical University, 639 Longmian Avenue, Nanjing 211198, China.
| | - A P Lepique
- Department of Immunology, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av.Prof. Lineu Prestes, 1730, room 136, Biomedicas IV Building, São Paulo CEP 05508-000, SP, Brazil.
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10
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Abstract
Chromosome instability (CIN) is a major hallmark of cancer cells and believed to drive tumor progression. Several cellular defects including weak centromeric cohesion are proposed to promote CIN, but the molecular mechanisms underlying these defects are poorly understood. In a screening for SET protein levels in various cancer cell lines, we found that most of the cancer cells exhibit higher SET protein levels than nontransformed cells, including RPE-1. Cancer cells with elevated SET often show weak centromeric cohesion, revealed by MG132-induced cohesion fatigue. Partial SET knockdown largely strengthens centromeric cohesion in cancer cells without increasing overall phosphatase 2A (PP2A) activity. Pharmacologically increased PP2A activity in these cancer cells barely ameliorates centromeric cohesion. These results suggest that compromised PP2A activity, a common phenomenon in cancer cells, may not be responsible for weak centromeric cohesion. Furthermore, centromeric cohesion in cancer cells can be strengthened by ectopic Sgo1 overexpression and weakened by SET WT, not by Sgo1-binding-deficient mutants. Altogether, these findings demonstrate that SET overexpression contributes to impaired centromeric cohesion in cancer cells and illustrate misregulated SET-Sgo1 pathway as an underlying mechanism.
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Affiliation(s)
- Lu Yang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112
| | - Qian Zhang
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112
| | - Tianhua Niu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112
| | - Hong Liu
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA 70112.,Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112.,Tulane Aging Center, Tulane University School of Medicine, New Orleans, LA 70112
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11
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Abstract
MYC is a master transcriptional regulator that controls almost all cellular processes. Over the last several decades, researchers have strived to define the context-dependent transcriptional gene programs that are controlled by MYC, as well as the mechanisms that regulate MYC function, in an effort to better understand the contribution of this oncoprotein to cancer progression. There are a wealth of data indicating that deregulation of MYC activity occurs in a large number of cancers and significantly contributes to disease progression, metastatic potential, and therapeutic resistance. Although the therapeutic targeting of MYC in cancer is highly desirable, there remain substantial structural and functional challenges that have impeded direct MYC-targeted drug development and efficacy. While efforts to drug the ‘undruggable’ may seem futile given these challenges and considering the broad reach of MYC, significant strides have been made to identify points of regulation that can be exploited for therapeutic purposes. These include targeting the deregulation of MYC transcription in cancer through small-molecule inhibitors that induce epigenetic silencing or that regulate the G-quadruplex structures within the MYC promoter. Alternatively, compounds that disrupt the DNA-binding activities of MYC have been the long-standing focus of many research groups, since this method would prevent downstream MYC oncogenic activities regardless of upstream alterations. Finally, proteins involved in the post-translational regulation of MYC have been identified as important surrogate targets to reduce MYC activity downstream of aberrant cell stimulatory signals. Given the complex regulation of the MYC signaling pathway, a combination of these approaches may provide the most durable response, but this has yet to be shown. Here, we provide a comprehensive overview of the different therapeutic strategies being employed to target oncogenic MYC function, with a focus on post-translational mechanisms.
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12
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Farrington CC, Yuan E, Mazhar S, Izadmehr S, Hurst L, Allen-Petersen BL, Janghorban M, Chung E, Wolczanski G, Galsky M, Sears R, Sangodkar J, Narla G. Protein phosphatase 2A activation as a therapeutic strategy for managing MYC-driven cancers. J Biol Chem 2020. [DOI: 10.1016/s0021-9258(17)49933-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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13
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Farrington CC, Yuan E, Mazhar S, Izadmehr S, Hurst L, Allen-Petersen BL, Janghorban M, Chung E, Wolczanski G, Galsky M, Sears R, Sangodkar J, Narla G. Protein phosphatase 2A activation as a therapeutic strategy for managing MYC-driven cancers. J Biol Chem 2019; 295:757-770. [PMID: 31822503 DOI: 10.1074/jbc.ra119.011443] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/04/2019] [Indexed: 12/14/2022] Open
Abstract
The tumor suppressor protein phosphatase 2A (PP2A) is a serine/threonine phosphatase whose activity is inhibited in most human cancers. One of the best-characterized PP2A substrates is MYC proto-oncogene basic helix-loop-helix transcription factor (MYC), whose overexpression is commonly associated with aggressive forms of this disease. PP2A directly dephosphorylates MYC, resulting in its degradation. To explore the therapeutic potential of direct PP2A activation in a diverse set of MYC-driven cancers, here we used biochemical assays, recombinant cell lines, gene expression analyses, and immunohistochemistry to evaluate a series of first-in-class small-molecule activators of PP2A (SMAPs) in Burkitt lymphoma, KRAS-driven non-small cell lung cancer, and triple-negative breast cancer. In all tested models of MYC-driven cancer, the SMAP treatment rapidly and persistently inhibited MYC expression through proteasome-mediated degradation, inhibition of MYC transcriptional activity, decreased cancer cell proliferation, and tumor growth inhibition. Importantly, we generated a series of cell lines expressing PP2A-dependent phosphodegron variants of MYC and demonstrated that the antitumorigenic activity of SMAPs depends on MYC degradation. Collectively, the findings presented here indicate a pharmacologically tractable approach to drive MYC degradation by using SMAPs for the management of a broad range of MYC-driven cancers.
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Affiliation(s)
| | - Eric Yuan
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio 44106
| | - Sahar Mazhar
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Sudeh Izadmehr
- Department of Medicine, Division of Hematology and Medical Oncology, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Lauren Hurst
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48105
| | - Brittany L Allen-Petersen
- Department of Molecular and Medical Genetics, Oregon Health and Sciences University, Portland, Oregon 97239
| | - Mahnaz Janghorban
- Department of Molecular and Medical Genetics, Oregon Health and Sciences University, Portland, Oregon 97239
| | - Eric Chung
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio 44106
| | - Grace Wolczanski
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48105
| | - Matthew Galsky
- Department of Medicine, Division of Hematology and Medical Oncology, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029
| | - Rosalie Sears
- Department of Molecular and Medical Genetics, Oregon Health and Sciences University, Portland, Oregon 97239
| | - Jaya Sangodkar
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48105
| | - Goutham Narla
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48105
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14
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Clark AR, Ohlmeyer M. Protein phosphatase 2A as a therapeutic target in inflammation and neurodegeneration. Pharmacol Ther 2019; 201:181-201. [PMID: 31158394 PMCID: PMC6700395 DOI: 10.1016/j.pharmthera.2019.05.016] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 12/11/2022]
Abstract
Protein phosphatase 2A (PP2A) is a highly complex heterotrimeric enzyme that catalyzes the selective removal of phosphate groups from protein serine and threonine residues. Emerging evidence suggests that it functions as a tumor suppressor by constraining phosphorylation-dependent signalling pathways that regulate cellular transformation and metastasis. Therefore, PP2A-activating drugs (PADs) are being actively sought and investigated as potential novel anti-cancer treatments. Here we explore the concept that PP2A also constrains inflammatory responses through its inhibitory effects on various signalling pathways, suggesting that PADs may be effective in the treatment of inflammation-mediated pathologies.
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Affiliation(s)
- Andrew R Clark
- Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
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15
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Yin L, Zeng Y, Xiao Y, Chen Y, Shen H, Dong J. Cyclin-dependent kinase 1-mediated phosphorylation of SET at serine 7 is essential for its oncogenic activity. Cell Death Dis 2019; 10:385. [PMID: 31097686 PMCID: PMC6522553 DOI: 10.1038/s41419-019-1621-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/24/2019] [Accepted: 04/29/2019] [Indexed: 01/02/2023]
Abstract
SE translocation (SET), an inhibitor of protein phosphatase 2A (PP2A), plays important roles in mitosis and possesses oncogenic activity in several types of cancer. However, little is known regarding its regulation. Here we reveal a novel phosphorylation site of SET isoform 1, and we have determined its biological significance in tumorigenesis. We found that the mitotic kinase cyclin-dependent kinase 1 (CDK1) phosphorylates SET isoform 1 in vitro and in vivo at serine 7 during antitubulin drug-induced mitotic arrest and normal mitosis. SET deletion resulted in massive multipolar spindles, chromosome misalignment and missegregation, and centrosome amplification during mitosis. Moreover, mitotic phosphorylation of SET isoform 1 is required for cell migration, invasion, and anchorage-independent growth in vitro and tumorigenesis in xenograft animal models. We further documented that SET phosphorylation affects Akt activity. Collectively, our findings suggest that SET isoform 1 promotes oncogenesis in a mitotic phosphorylation-dependent manner.
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Affiliation(s)
- Ling Yin
- Department of Oncology, Xiangya Hospital, Central South University, 410008, Changsha, China
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Yongji Zeng
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Yi Xiao
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
- Department of Biochemistry and Molecular Biology, Shandong University School of Basic Medical Science, 250012, Jinan, China
| | - Yuanhong Chen
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Hong Shen
- Department of Oncology, Xiangya Hospital, Central South University, 410008, Changsha, China
| | - Jixin Dong
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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16
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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: 65] [Impact Index Per Article: 10.8] [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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17
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Wei Y, Maximov V, Morrissy SA, Taylor MD, Pallas DC, Kenney AM. p53 Function Is Compromised by Inhibitor 2 of Phosphatase 2A in Sonic Hedgehog Medulloblastoma. Mol Cancer Res 2018; 17:186-198. [PMID: 30224541 DOI: 10.1158/1541-7786.mcr-18-0485] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/10/2018] [Accepted: 08/21/2018] [Indexed: 01/09/2023]
Abstract
Medulloblastomas, the most common malignant pediatric brain tumors, have been genetically defined into four subclasses, namely WNT-activated, Sonic Hedgehog (SHH)-activated, Group 3, and Group 4. Approximately 30% of medulloblastomas have aberrant SHH signaling and thus are referred to as SHH-activated medulloblastoma. The tumor suppressor gene TP53 has been recently recognized as a prognostic marker for patients with SHH-activated medulloblastoma; patients with mutant TP53 have a significantly worse outcome than those with wild-type TP53. It remains unknown whether p53 activity is impaired in SHH-activated, wild-type TP53 medulloblastoma, which is about 80% of the SHH-activated medulloblastomas. Utilizing the homozygous NeuroD2:SmoA1 mouse model with wild-type Trp53, which recapitulates human SHH-activated medulloblastoma, it was discovered that the endogenous Inhibitor 2 of Protein Phosphatase 2A (SET/I2PP2A) suppresses p53 function by promoting accumulation of phospho-MDM2 (S166), an active form of MDM2 that negatively regulates p53. Knockdown of I2PP2A in SmoA1 primary medulloblastoma cells reduced viability and proliferation in a p53-dependent manner, indicating the oncogenic role of I2PP2A. Importantly, this mechanism is conserved in the human medulloblastoma cell line ONS76 with wild-type TP53. Taken together, these findings indicate that p53 activity is inhibited by I2PP2A upstream of PP2A in SHH-activated and TP53-wildtype medulloblastomas. IMPLICATIONS: This study suggests that I2PP2A represents a novel therapeutic option and its targeting could improve the effectiveness of current therapeutic regimens for SHH-activated or other subclasses of medulloblastoma with wild-type TP53.
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Affiliation(s)
- Yun Wei
- Department of Pediatrics, Emory University, Atlanta, Georgia.,Winship Cancer Institute, Atlanta, Georgia
| | - Victor Maximov
- Department of Pediatrics, Emory University, Atlanta, Georgia
| | - Sorana A Morrissy
- Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Michael D Taylor
- The Hospital for Sick Children (SickKids), University of Toronto, Toronto, Ontario, Canada
| | - David C Pallas
- Winship Cancer Institute, Atlanta, Georgia.,Department of Biochemistry, Emory University, Atlanta, Georgia
| | - Anna Marie Kenney
- Department of Pediatrics, Emory University, Atlanta, Georgia. .,Winship Cancer Institute, Atlanta, Georgia
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18
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Sipeky C, Gao P, Zhang Q, Wang L, Ettala O, Talala KM, Tammela TLJ, Auvinen A, Wiklund F, Wei GH, Schleutker J. Synergistic Interaction of HOXB13 and CIP2A Predisposes to Aggressive Prostate Cancer. Clin Cancer Res 2018; 24:6265-6276. [PMID: 30181389 DOI: 10.1158/1078-0432.ccr-18-0444] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/09/2018] [Accepted: 08/28/2018] [Indexed: 11/16/2022]
Abstract
PURPOSE Distinguishing aggressive prostate cancer from indolent disease improves personalized treatment. Although only few genetic variants are known to predispose to aggressive prostate cancer, synergistic interactions of HOXB13 G84E high-risk prostate cancer susceptibility mutation with other genetic loci remain unknown. The purpose of this study was to examine the interplay of HOXB13 rs138213197 (G84E) and CIP2A rs2278911 (R229Q) germline variants on prostate cancer risk. EXPERIMENTAL DESIGN Genotyping was done in Finnish discovery cohort (n = 2,738) and validated in Swedish (n = 3,132) and independent Finnish (n = 1,155) prostate cancer cohorts. Expression pattern analysis was followed by functional studies in prostate cancer cell models. RESULTS Interplay of HOXB13 (G84E) and CIP2A (R229Q) variants results in highest observed inherited prostate cancer risk (OR, 21.1; P = 0.000024). In addition, this synergism indicates a significant association of HOXB13 T and CIP2A T dual carriers with elevated risk for high Gleason score (OR, 2.3; P = 0.025) and worse prostate cancer-specific life expectancy (HR, 3.9; P = 0.048), and it is linked with high PSA at diagnosis (OR, 3.30; P = 0.028). Furthermore, combined high expression of HOXB13-CIP2A correlates with earlier biochemical recurrence. Finally, functional experiments showed that ectopic expression of variants stimulates prostate cancer cell growth and migration. In addition, we observed strong chromatin binding of HOXB13 at CIP2A locus and revealed that HOXB13 functionally promotes CIP2A transcription. The study is limited to retrospective Nordic cohorts. CONCLUSIONS Simultaneous presence of HOXB13 T and CIP2A T alleles confers for high prostate cancer risk and aggressiveness of disease, earlier biochemical relapse, and lower disease-specific life expectancy. HOXB13 protein binds to CIP2A gene and functionally promotes CIP2A transcription.
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Affiliation(s)
- Csilla Sipeky
- Institute of Biomedicine, University of Turku, Turku, Finland
| | - Ping Gao
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Qin Zhang
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Liang Wang
- Department of Pathology, MCW Cancer Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Otto Ettala
- Department of Urology, Turku University Hospital, Turku, Finland
| | - Kirsi M Talala
- Finnish Cancer Registry, Mass Screening Registry, Helsinki, Finland
| | - Teuvo L J Tammela
- Department of Urology, Tampere University Hospital and Medical School, University of Tampere, Tampere, Finland
| | - Anssi Auvinen
- Department of Epidemiology, School of Health Sciences, University of Tampere, Tampere, Finland
| | - Fredrik Wiklund
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden
| | - Gong-Hong Wei
- Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
| | - Johanna Schleutker
- Institute of Biomedicine, University of Turku, Turku, Finland. .,Tyks Microbiology and Genetics, Department of Medical Genetics, Turku University Hospital, Turku, Finland
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19
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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: 3.7] [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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20
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Almeida LO, Neto MPC, Sousa LO, Tannous MA, Curti C, Leopoldino AM. SET oncoprotein accumulation regulates transcription through DNA demethylation and histone hypoacetylation. Oncotarget 2018; 8:26802-26818. [PMID: 28460463 PMCID: PMC5432298 DOI: 10.18632/oncotarget.15818] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 02/20/2017] [Indexed: 01/23/2023] Open
Abstract
Epigenetic modifications are essential in the control of normal cellular processes and cancer development. DNA methylation and histone acetylation are major epigenetic modifications involved in gene transcription and abnormal events driving the oncogenic process. SET protein accumulates in many cancer types, including head and neck squamous cell carcinoma (HNSCC); SET is a member of the INHAT complex that inhibits gene transcription associating with histones and preventing their acetylation. We explored how SET protein accumulation impacts on the regulation of gene expression, focusing on DNA methylation and histone acetylation. DNA methylation profile of 24 tumour suppressors evidenced that SET accumulation decreased DNA methylation in association with loss of 5-methylcytidine, formation of 5-hydroxymethylcytosine and increased TET1 levels, indicating an active DNA demethylation mechanism. However, the expression of some suppressor genes was lowered in cells with high SET levels, suggesting that loss of methylation is not the main mechanism modulating gene expression. SET accumulation also downregulated the expression of 32 genes of a panel of 84 transcription factors, and SET directly interacted with chromatin at the promoter of the downregulated genes, decreasing histone acetylation. Gene expression analysis after cell treatment with 5-aza-2′-deoxycytidine (5-AZA) and Trichostatin A (TSA) revealed that histone acetylation reversed transcription repression promoted by SET. These results suggest a new function for SET in the regulation of chromatin dynamics. In addition, TSA diminished both SET protein levels and SET capability to bind to gene promoter, suggesting that administration of epigenetic modifier agents could be efficient to reverse SET phenotype in cancer.
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Affiliation(s)
- Luciana O Almeida
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.,Department of Genetics and Evolution, Federal University of São Carlos, São Carlos, SP, Brazil
| | - Marinaldo P C Neto
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Lucas O Sousa
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Maryna A Tannous
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Carlos Curti
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Andreia M Leopoldino
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.,CEPID-FAPESP, Center for Cell Based Therapy, Hemotherapy Center of Ribeirão Preto, Ribeirão Preto, SP, Brazil
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21
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McClinch K, Avelar RA, Callejas D, Izadmehr S, Wiredja D, Perl A, Sangodkar J, Kastrinsky DB, Schlatzer D, Cooper M, Kiselar J, Stachnik A, Yao S, Hoon D, McQuaid D, Zaware N, Gong Y, Brautigan DL, Plymate SR, Sprenger CCT, Oh WK, Levine AC, Kirschenbaum A, Sfakianos JP, Sears R, DiFeo A, Ioannou Y, Ohlmeyer M, Narla G, Galsky MD. Small-Molecule Activators of Protein Phosphatase 2A for the Treatment of Castration-Resistant Prostate Cancer. Cancer Res 2018; 78:2065-2080. [PMID: 29358171 DOI: 10.1158/0008-5472.can-17-0123] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 05/13/2017] [Accepted: 01/17/2018] [Indexed: 02/01/2023]
Abstract
Primary prostate cancer is generally treatable by androgen deprivation therapy, however, later recurrences of castrate-resistant prostate cancer (CRPC) that are more difficult to treat nearly always occur due to aberrant reactivation of the androgen receptor (AR). In this study, we report that CRPC cells are particularly sensitive to the growth-inhibitory effects of reengineered tricyclic sulfonamides, a class of molecules that activate the protein phosphatase PP2A, which inhibits multiple oncogenic signaling pathways. Treatment of CRPC cells with small-molecule activators of PP2A (SMAP) in vitro decreased cellular viability and clonogenicity and induced apoptosis. SMAP treatment also induced an array of significant changes in the phosphoproteome, including most notably dephosphorylation of full-length and truncated isoforms of the AR and downregulation of its regulatory kinases in a dose-dependent and time-dependent manner. In murine xenograft models of human CRPC, the potent compound SMAP-2 exhibited efficacy comparable with enzalutamide in inhibiting tumor formation. Overall, our results provide a preclinical proof of concept for the efficacy of SMAP in AR degradation and CRPC treatment.Significance: A novel class of small-molecule activators of the tumor suppressor PP2A, a serine/threonine phosphatase that inhibits many oncogenic signaling pathways, is shown to deregulate the phosphoproteome and to destabilize the androgen receptor in advanced prostate cancer. Cancer Res; 78(8); 2065-80. ©2018 AACR.
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Affiliation(s)
- Kimberly McClinch
- Department of Medicine, Division of Hematology and Medical Oncology, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Rita A Avelar
- Department of Medicine, Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, Ohio
| | - David Callejas
- Department of Medicine, Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Sudeh Izadmehr
- Department of Medicine, Division of Hematology and Medical Oncology, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Danica Wiredja
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Abbey Perl
- Department of Medicine, Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Jaya Sangodkar
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - David B Kastrinsky
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio
| | - Daniela Schlatzer
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Maxwell Cooper
- Department of Medicine, Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Janna Kiselar
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Agnes Stachnik
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Shen Yao
- Department of Medicine, Division of Endocrine, Diabetes and Bone Diseases, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Divya Hoon
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Daniel McQuaid
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Nilesh Zaware
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio
| | - Yixuan Gong
- Department of Medicine, Division of Hematology and Medical Oncology, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - David L Brautigan
- Center for Cell Signaling, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Stephen R Plymate
- Department of Medicine, University of Washington School of Medicine, Seattle, Washington
| | - Cynthia C T Sprenger
- Department of Medicine, University of Washington School of Medicine, Seattle, Washington
| | - William K Oh
- Department of Medicine, Division of Hematology and Medical Oncology, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Alice C Levine
- Department of Medicine, Division of Endocrine, Diabetes and Bone Diseases, Icahn School of Medicine at Mount Sinai, New York, New York
| | | | - John P Sfakianos
- Department of Urology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Rosalie Sears
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon
| | - Analisa DiFeo
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio
| | - Yiannis Ioannou
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Michael Ohlmeyer
- Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, Ohio
| | - Goutham Narla
- Department of Medicine, Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, Ohio.
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio
| | - Matthew D Galsky
- Department of Medicine, Division of Hematology and Medical Oncology, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
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22
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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: 35] [Impact Index Per Article: 5.0] [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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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: 9] [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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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: 67] [Impact Index Per Article: 8.4] [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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25
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Cristóbal I, Torrejón B, Martínez-Useros J, Madoz-Gurpide J, Rojo F, García-Foncillas J. PP2A regulates signaling through hormonal receptors in breast cancer with important therapeutic implications. Biochim Biophys Acta Rev Cancer 2017; 1868:435-438. [PMID: 28916342 DOI: 10.1016/j.bbcan.2017.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/10/2017] [Accepted: 08/31/2017] [Indexed: 11/27/2022]
Abstract
The functional inhibition of protein phosphatase 2A (PP2A) has emerged in the last years as a common alteration in breast cancer that determines poor outcome and contributes to disease progression and aggressiveness. Furthermore, expression of estrogen receptor (ER) is a high relevant molecular event with key therapeutic implications in breast cancer, and androgen receptor (AR) signaling is involved in the pathogenesis of breast cancer and represents a novel target with crescent importance in this disease. In this review, we summarize the role of the tumor suppressor PP2A in modulating ER and AR signaling in breast cancer, the molecular mechanisms involved, and its biological and therapeutic impact.
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Affiliation(s)
- Ion Cristóbal
- Translational Oncology Division, Oncohealth Institute, IIS-Fundacion Jimenez Diaz, UAM, University Hospital "Fundacion Jimenez Diaz", Madrid, Spain.
| | - Blanca Torrejón
- Translational Oncology Division, Oncohealth Institute, IIS-Fundacion Jimenez Diaz, UAM, University Hospital "Fundacion Jimenez Diaz", Madrid, Spain
| | - Javier Martínez-Useros
- Translational Oncology Division, Oncohealth Institute, IIS-Fundacion Jimenez Diaz, UAM, University Hospital "Fundacion Jimenez Diaz", Madrid, Spain
| | | | - Federico Rojo
- Pathology Department, IIS "Fundación Jiménez Diaz", Madrid, Spain.
| | - Jesús García-Foncillas
- Translational Oncology Division, Oncohealth Institute, IIS-Fundacion Jimenez Diaz, UAM, University Hospital "Fundacion Jimenez Diaz", Madrid, Spain.
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26
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Phosphatases and solid tumors: focus on glioblastoma initiation, progression and recurrences. Biochem J 2017; 474:2903-2924. [PMID: 28801478 DOI: 10.1042/bcj20170112] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 06/21/2017] [Accepted: 06/23/2017] [Indexed: 12/15/2022]
Abstract
Phosphatases and cancer have been related for many years now, as these enzymes regulate key cellular functions, including cell survival, migration, differentiation and proliferation. Dysfunctions or mutations affecting these enzymes have been demonstrated to be key factors for oncogenesis. The aim of this review is to shed light on the role of four different phosphatases (PTEN, PP2A, CDC25 and DUSP1) in five different solid tumors (breast cancer, lung cancer, pancreatic cancer, prostate cancer and ovarian cancer), in order to better understand the most frequent and aggressive primary cancer of the central nervous system, glioblastoma.
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27
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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: 2.0] [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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28
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Jiang SW, Xu S, Chen H, Liu X, Tang Z, Cui Y, Liu J. Pathologic significance of SET/I2PP2A-mediated PP2A and non-PP2A pathways in polycystic ovary syndrome (PCOS). Clin Chim Acta 2017; 464:155-159. [PMID: 27836688 DOI: 10.1016/j.cca.2016.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 11/06/2016] [Accepted: 11/07/2016] [Indexed: 02/05/2023]
Abstract
SET (SE translocation, SET), a constitutive inhibitor of protein phosphatase 2A (PP2A), is a multifunctional oncoprotein involved in DNA replication, histone modification, nucleosome assembly, gene transcription and cell proliferation. It is widely expressed in human tissues including the gonadal system and brain. Intensive studies have shown that overexpressed SET plays an important role in the development of Alzheimer's disease (AD), and may also contribute to the malignant transformation of breast and ovarian cancers. Recent studies indicated that through interaction with PP2A, SET may upregulate androgen biosynthesis and contribute to hyperandrogenism in polycystic ovary syndrome (PCOS) patients. This review article summarizes data concerning the SET expression in ovaries from PCOS and normal women, and analyzes the role/regulatory mechanism of SET for androgen biosynthesis in PCOS, as well as the significance of this action in the development of PCOS. The potential value of SET-triggered pathway as a therapeutic target and the application of anti-SET reagents for treating hyperandrogenism in PCOS patients are also discussed.
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Affiliation(s)
- Shi-Wen Jiang
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital, Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, China; Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, USA.
| | - Siliang Xu
- Department of Biomedical Science, Mercer University School of Medicine, Savannah, GA, USA; The State Key Laboratory of Reproductive Medicine, Clinical Center of Reproductive Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Haibin Chen
- Department of Histology and Embryology, Shantou University Medical College, Shantou, Guangdong 515000, China
| | - Xiaoqiang Liu
- The Third People's Hospital of Qingdao, Department of Obstetrics and Gynecology, Qingdao, Shandong 266041, China; Department of Medical Genetics and Developmental Biology, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Zuoqing Tang
- Department of Medical Genetics, School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Yugui Cui
- The State Key Laboratory of Reproductive Medicine, Clinical Center of Reproductive Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Jiayin Liu
- The State Key Laboratory of Reproductive Medicine, Clinical Center of Reproductive Medicine, First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
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29
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Cristóbal I, Torrejón B, Pedregal M, Rojo F, García-Foncillas J. Targeting PP2A to overcome enzalutamide resistance in AR+ breast tumors. Endocr Relat Cancer 2017; 24:L5-L6. [PMID: 27765801 DOI: 10.1530/erc-16-0444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 10/20/2016] [Indexed: 01/06/2023]
Affiliation(s)
- Ion Cristóbal
- Translational Oncology DivisionOncohealth Institute, IIS-Fundacion Jimenez Diaz-UAM, University Hospital 'Fundacion Jimenez Diaz', Madrid, Spain
| | - Blanca Torrejón
- Translational Oncology DivisionOncohealth Institute, IIS-Fundacion Jimenez Diaz-UAM, University Hospital 'Fundacion Jimenez Diaz', Madrid, Spain
| | - Manuel Pedregal
- Translational Oncology DivisionOncohealth Institute, IIS-Fundacion Jimenez Diaz-UAM, University Hospital 'Fundacion Jimenez Diaz', Madrid, Spain
| | - Federico Rojo
- Pathology DepartmentIIS-Fundacion Jimenez Diaz-UAM, University Hospital 'Fundacion Jimenez Diaz', Madrid, Spain
| | - Jesús García-Foncillas
- Translational Oncology DivisionOncohealth Institute, IIS-Fundacion Jimenez Diaz-UAM, University Hospital 'Fundacion Jimenez Diaz', Madrid, Spain
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30
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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: 2.7] [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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