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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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Peris I, Romero-Murillo S, Vicente C, Narla G, Odero MD. Regulation and role of the PP2A-B56 holoenzyme family in cancer. Biochim Biophys Acta Rev Cancer 2023; 1878:188953. [PMID: 37437699 DOI: 10.1016/j.bbcan.2023.188953] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 07/07/2023] [Accepted: 07/08/2023] [Indexed: 07/14/2023]
Abstract
Protein phosphatase 2A (PP2A) inactivation is common in cancer, leading to sustained activation of pro-survival and growth-promoting pathways. PP2A consists of a scaffolding A-subunit, a catalytic C-subunit, and a regulatory B-subunit. The functional complexity of PP2A holoenzymes arises mainly through the vast repertoire of regulatory B-subunits, which determine both their substrate specificity and their subcellular localization. Therefore, a major challenge for developing more effective therapeutic strategies for cancer is to identify the specific PP2A complexes to be targeted. Of note, the development of small molecules specifically directed at PP2A-B56α has opened new therapeutic avenues in both solid and hematological tumors. Here, we focus on the B56/PR61 family of PP2A regulatory subunits, which have a central role in directing PP2A tumor suppressor activity. We provide an overview of the mechanisms controlling the formation and regulation of these complexes, the pathways they control, and the mechanisms underlying their deregulation in cancer.
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Affiliation(s)
- Irene Peris
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.
| | - Silvia Romero-Murillo
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain
| | - Carmen Vicente
- Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Goutham Narla
- Division of Genetic Medicine, Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI, USA
| | - Maria D Odero
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain; Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain; Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain; CIBERONC, Instituto de Salud Carlos III, Madrid, Spain.
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You M, Song Y, Chen J, Liu Y, Chen W, Cen Y, Zhao X, Tao Z, Yang G. Combined exposure to benzo(a)pyrene and dibutyl phthalate aggravates pro-inflammatory macrophage polarization in spleen via pyroptosis involving cathepsin B. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 881:163460. [PMID: 37061049 DOI: 10.1016/j.scitotenv.2023.163460] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/23/2023] [Accepted: 04/08/2023] [Indexed: 06/01/2023]
Abstract
Humans are often simultaneously exposed to benzo(a)pyrene (BaP) and dibutyl phthalate (DBP) through consumption of food and water. Yet, direct evidence of the link between BaP and DBP co-exposure and the risk of splenic injury is lacking. In the present study, we established the rats and primary splenic macrophages models to evaluate the effects of BaP or/and DBP exposure on spleen and underlying mechanisms. Compared to the single exposure or control groups, the co-exposure group showed more severe spleen damage and higher production of pro-inflammatory cytokines. Co-exposure to BaP and DBP resulted in a 1.79-fold, 2.11-fold and 1.9-fold increase in the M1 macrophage markers iNOS, NLRP3 (pyroptosis marker protein) and cathepsin B (CTSB), respectively, and a 0.8-fold decrease in the M2 macrophage marker Arg1 in vivo. The more prominent effects in perturbation of imbalance in M1/M2 polarization (iNOS, 2.25-fold; Arg1, 0.55-fold), pyroptosis (NLRP3, 1.43-fold), and excess CTSB (1.07-fold) in macrophages caused by BaP and DBP co-exposure in vitro were also found. Notably, MCC950 (the NLRP3-specific inhibitor) treatment attenuated the pro-inflammatory macrophage polarization and following pro-inflammatory cytokine production triggered by BaP and DBP co-exposure. Furthermore, CA-074Me (the CTSB-specific inhibitor) suppressed the macrophages pyroptosis, pro-inflammatory macrophage polarization, and secretion of pro-inflammatory cytokine induced by BaP and DBP co-exposure. In conclusion, this study indicates co-exposure to BaP and DBP poses a higher risk of spleen injury. Pro-inflammatory macrophage polarization regulated by pyroptosis involving CTSB underlies the spleen injury caused by BaP and DBP co-exposure.
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Affiliation(s)
- Mingdan You
- School of Public Health, the key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, China
| | - Yawen Song
- School of Public Health, the key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, China
| | - Jing Chen
- School of Public Health, the key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, China
| | - Yining Liu
- School of Public Health, the key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, China
| | - Wenyan Chen
- School of Public Health, the key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, China
| | - Yanli Cen
- School of Public Health, the key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, China
| | - Xiaodeng Zhao
- Guizhou Center for Disease Control and Prevention, Guiyang, Guizhou 550004, China
| | - Zhongfa Tao
- Guizhou Center for Disease Control and Prevention, Guiyang, Guizhou 550004, China
| | - Ganghong Yang
- Guizhou Center for Disease Control and Prevention, Guiyang, Guizhou 550004, China; School of Public Health, Guizhou Medical University, Guiyang 550025, China.
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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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da Silva G, de Matos LL, Kowalski LP, Kulcsar M, Leopoldino AM. Profile of sphingolipid-related genes and its association with prognosis highlights sphingolipid metabolism in oral cancer. Cancer Biomark 2021; 32:49-63. [PMID: 34092610 DOI: 10.3233/cbm-203100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Sphingolipids are bioactive lipids that play a role in cancer development. However, the clinical role of sphingolipid (SPL)-related genes in oral cancer (OC) remains not fully understood. OBJECTIVE This study, aimed to examine the mRNA expression of 14 sphingolipid-related genes in oral cancer patients and their implication with clinicopathological features and prognosis. METHODS qPCR analysis was performed in 50 OC tissues and their matched surgical margins. Next, Kaplan-Meier, Cox regression, and Receiver operating characteristics (ROC) analysis were applied to evaluate the impact of sphingolipid-related genes expression on the prognosis of OC. RESULTS The genes SET, ACER3, SK1 and S1PR5 were predominantly up-regulated, while ABCG2, S1PR1, ABCB1 and SPNS2 were down-regulated in OC patients. Analyzing the Cancer Genome Atlas Head-Neck Squamous Cell Carcinoma (TCGA-HNSC) data, which are predominantly composed of OC samples, these genes displayed a similar profile. In OC patients, high levels of SK1 were associated with lymph node metastasis, extracapsular invasion, desmoplasia, locoregional relapse, and disease status. Low levels of SPNS2 were associated with lymph node metastasis, perineural invasion, and disease status. Furthermore, OC and HNSC patients with higher SK1 expression demonstrated shorter disease-free survival (p= 0.0037; p= 0.0087), whereas those with lower SPNS2 expression exhibited shorter overall survival (p= 0.051; p= 0.0012). High levels of ACER3 and low levels of S1PR1 were associated with shorter disease-free and overall survival in HNSC patients. CONCLUSION Several sphingolipid-related genes are deregulated in OC at the mRNA level and are associated with clinicopathological features and presented potencial for the prediction of poor prognosis in OC patients.
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Affiliation(s)
- Gabriel da Silva
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, SP, Brazil
| | - Leandro Luongo de Matos
- Head and Neck Surgery Department, Instituto do Câncer do Estado de São Paulo, University of São Paulo Medical School (LIM28), SP, Brazil.,Surgery Department, Faculdade Israelita de Ciências da Saúde Albert Einstein, SP, Brazil
| | - Luiz Paulo Kowalski
- Surgery Department, Faculdade Israelita de Ciências da Saúde Albert Einstein, SP, Brazil.,Department of Head and Neck Surgery and Otorhinolaryngology, A. C. Camargo Cancer Center, SP, Brazil
| | - Marco Kulcsar
- Head and Neck Surgery Department, Instituto do Câncer do Estado de São Paulo, University of São Paulo Medical School (LIM28), SP, Brazil
| | - Andreia Machado Leopoldino
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, SP, Brazil
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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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Baldino MEL, Medina-Silva R, Sumienski J, Figueiredo MA, Salum FG, Cherubini K. Nystatin effect on chlorhexidine efficacy against Streptococcus mutans as planktonic cells and mixed biofilm with Candida albicans. Clin Oral Investig 2021; 26:633-642. [PMID: 34160701 PMCID: PMC8219785 DOI: 10.1007/s00784-021-04041-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 06/17/2021] [Indexed: 01/23/2023]
Abstract
Objective The aim of this study was to evaluate the effect of nystatin on the efficacy of chlorhexidine against Streptococcus mutans in planktonic cells and mixed biofilm with Candida albicans. Material and methods S. mutans ATCC 25,175 in suspension and also combined with C. albicans ATCC 18,804 in biofilm were cultured. Minimum inhibitory concentration (MIC), crystal violet colorimetric assay, and colony-forming unit counting (CFUs/mL) were performed. Results An increased MIC of chlorhexidine against S. mutans was observed when the drugs were administered mixed in a single formulation and with time intervals in between, except for the 30-min interval. The biofilm optical density (OD) in treatments using chlorhexidine and nystatin combined did not significantly differ from chlorhexidine alone. Either in biofilm colorimetric assay or determination of CFUs, the combined treatments with nystatin administered before chlorhexidine had less effect on chlorhexidine efficacy. Conclusions Nystatin interferes with the action of chlorhexidine against S. mutans. The antimicrobial effectiveness of the combined drugs depends on their concentration, time interval used, and the planktonic or biofilm behavior of the microorganisms. Clinical relevance In view of the great number of patients that can receive a prescription of chlorhexidine and nystatin concomitantly, this study contributes to the knowledge about the effect of the combined drugs. Given the high prevalence of prescriptions of chlorhexidine and nystatin in dentistry, dental professionals should be aware of their possible antagonistic effect.
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Affiliation(s)
- Maria Eduarda Lanes Baldino
- Post-Graduate Program, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Renata Medina-Silva
- Laboratory of Immunology and Microbiology, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Juliana Sumienski
- Laboratory of Immunology and Microbiology, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Maria Antonia Figueiredo
- Post-Graduate Program, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Fernanda Gonçalves Salum
- Post-Graduate Program, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Karen Cherubini
- Post-Graduate Program, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande Do Sul, Porto Alegre, RS, Brazil.
- Serviço de Estomatologia - Hospital São Lucas, PUCRS, Av. Ipiranga, 6690 Sala 231, Porto Alegre, RS, CEP 90610-000, Brazil.
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