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Zhao YX, Ma LB, Yang Z, Wang F, Wang HY, Dang JY. Cancerous inhibitor of protein phosphatase 2A enhances chemoresistance of gastric cancer cells to oxaliplatin. World J Gastrointest Oncol 2023; 15:286-302. [PMID: 36908323 PMCID: PMC9994047 DOI: 10.4251/wjgo.v15.i2.286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/23/2022] [Accepted: 01/05/2023] [Indexed: 02/14/2023] Open
Abstract
BACKGROUND Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a newly discovered oncogene. It is an active cell proliferation regulatory factor that inhibits tumor apoptosis in gastric cancer (GC) cells. CIP2A is functionally related to chemoresistance in various types of tumors according to recent studies. The underlying mechanism, however, is unknown. Further, the primary treatment regimen for GC is oxaliplatin-based chemotherapy. Nonetheless, it often fails due to chemoresistance of GC cells to oxaliplatin.
AIM The goal of this study was to examine CIP2A expression and its association with oxaliplatin resistance in human GC cells.
METHODS Immunohistochemistry was used to examine CIP2A expression in GC tissues and adjacent normal tissues. CIP2A expression in GC cell lines was reduced using small interfering RNA. After confirming the silencing efficiency, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium and flow cytometry assays were used to evaluate cell proliferation and apoptosis caused by oxaliplatin treatment. Further, the key genes and protein changes were verified using real-time quantitative reverse transcription PCR and Western blotting, respectively, before and after intervention. For bioinformatics analysis, we used the R software and Bioconductor project. For statistical analysis, we used GraphPad Prism 6.0 and the Statistical Package for the Social Sciences software version 20.0 (IBM, Armonk, United States).
RESULTS A high level of CIP2A expression was associated with tumor size, T stage, lymph node metastasis, Tumor Node Metastasis stage, and a poor prognosis. Further, CIP2A expression was higher in GC cells than in normal human gastric epithelial cells. Using small interfering RNA against CIP2A, we discovered that CIP2A knockdown inhibited cell proliferation and significantly increased GC cell sensitivity to oxaliplatin. Moreover, CIP2A knockdown enhanced oxaliplatin-induced apoptosis in GC cells. Hence, high CIP2A levels in GC may be a factor in chemoresistance to oxaliplatin. In human GC cells, CIP2A regulated protein kinase B phosphorylation, and chemical inhibition of the protein kinase B signaling pathway was significantly associated with increased sensitivity to oxaliplatin. Therefore, the protein kinase B signaling pathway was correlated with CIP2A-enhanced chemoresistance of human GC cells to oxaliplatin.
CONCLUSION CIP2A expression could be a novel therapeutic strategy for chemoresistance in GC.
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Affiliation(s)
- Yong-Xun Zhao
- The Seventh Department of General Surgery, The First Hospital of Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Li-Bin Ma
- The Seventh Department of General Surgery, The First Hospital of Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Ze Yang
- The Seventh Department of General Surgery, The First Hospital of Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Fang Wang
- Department of Pathology, The First Hospital of Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Hui-Ying Wang
- The First Clinical Medical School, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Jia-Yao Dang
- The First Clinical Medical School, Lanzhou University, Lanzhou 730000, Gansu Province, China
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Chen B, Hu H, Chen X. From Basic Science to Clinical Practice: The Role of Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A)/p90 in Cancer. Front Genet 2023; 14:1110656. [PMID: 36911405 PMCID: PMC9998691 DOI: 10.3389/fgene.2023.1110656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/03/2023] [Indexed: 03/14/2023] Open
Abstract
Cancerous inhibitor of protein phosphatase 2A (CIP2A), initially reported as a tumor-associated antigen (known as p90), is highly expressed in most solid and hematological tumors. The interaction of CIP2A/p90, protein phosphatase 2A (PP2A), and c-Myc can hinder the function of PP2A toward c-Myc S62 induction, thus stabilizing c-Myc protein, which represents a potential role of CIP2A/p90 in tumorigeneses such as cell proliferation, invasion, and migration, as well as cancer drug resistance. The signaling pathways and regulation networks of CIP2A/p90 are complex and not yet fully understood. Many previous studies have also demonstrated that CIP2A/p90 can be used as a potential therapeutic cancer target. In addition, the autoantibody against CIP2A/p90 in sera may be used as a promising biomarker in the diagnosis of certain types of cancer. In this Review, we focus on recent advances relating to CIP2A/p90 and their implications for future research.
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Affiliation(s)
- Beibei Chen
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, Henan, China.,Zhengzhou Key Laboratory for Precision Therapy of Gastrointestinal Cancer, Zhengzhou, Henan, China
| | - Huihui Hu
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, Henan, China.,Zhengzhou Key Laboratory for Precision Therapy of Gastrointestinal Cancer, Zhengzhou, Henan, China
| | - Xiaobing Chen
- Department of Medical Oncology, Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou, Henan, China.,Zhengzhou Key Laboratory for Precision Therapy of Gastrointestinal Cancer, Zhengzhou, Henan, China
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The Pivotal Role of Protein Phosphatase 2A (PP2A) in Brain Tumors. Int J Mol Sci 2022; 23:ijms232415717. [PMID: 36555359 PMCID: PMC9779694 DOI: 10.3390/ijms232415717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/09/2022] [Accepted: 12/10/2022] [Indexed: 12/14/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is a highly complex heterotrimeric Ser/Thr phosphatase that regulates many cellular processes. PP2A is dysregulated in several human diseases, including oncological pathology; interestingly, PP2A appears to be essential for controlling cell growth and may be involved in cancer development. The role of PP2A as a tumor suppressor has been extensively studied and reviewed. To leverage the potential clinical utility of combination PP2A inhibition and radiotherapy treatment, it is vital that novel highly specific PP2A inhibitors be developed. In this review, the existing literature on the role of PP2A in brain tumors, especially in gliomas and glioblastoma (GBM), was analyzed. Interestingly, the review focused on the role of PP2A inhibitors, focusing on CIP2A inhibition, as CIP2A participated in tumor cell growth by stimulating cell-renewal survival, cellular proliferation, evasion of senescence and inhibition of apoptosis. This review suggested CIP2A inhibition as a promising strategy in oncology target therapy.
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Son HE, Jang WG. Cip2A modulates osteogenic differentiation via the ERK-Runx2 pathway in MG63 cells. Biofactors 2021; 47:658-664. [PMID: 34077593 DOI: 10.1002/biof.1760] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/08/2021] [Indexed: 01/25/2023]
Abstract
Cancerous inhibitor of protein phosphatase 2A (Cip2A) is an oncoprotein that promotes the development of several types of cancer. However, its molecular function in osteoblast differentiation remains unclear. In this study, we found that Cip2A was upregulated under osteogenic conditions in MG63 cells. Besides, overexpression of Cip2A significantly increased the expression of Runt-related transcription factor 2 (Runx2) and alkaline phosphatase (ALP). Inversely, the knockdown of Cip2A in MG63 cells suppressed osteoblast differentiation. Cip2A expression during osteogenic differentiation was mediated by extracellular signal-regulated kinase (ERK) activation. Taken together, our results suggest that Cip2A plays important role in regulating osteoblast differentiation by inducing ERK phosphorylation in MG63 cells.
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Affiliation(s)
- Hyo-Eun Son
- Department of Biotechnology, School of Engineering, Daegu University, Gyeongbuk, Republic of Korea
- Research Institute of Anti-Aging, Daegu University, Gyeongbuk, Republic of Korea
| | - Won-Gu Jang
- Department of Biotechnology, School of Engineering, Daegu University, Gyeongbuk, Republic of Korea
- Research Institute of Anti-Aging, Daegu University, Gyeongbuk, Republic of Korea
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Clark RE, Basabrain AA, Austin GM, Holcroft AK, Loaiza S, Apperley JF, Law C, Scott L, Parry AD, Bonnett L, Lucas CM. Validation of CIP2A as a Biomarker of Subsequent Disease Progression and Treatment Failure in Chronic Myeloid Leukaemia. Cancers (Basel) 2021; 13:cancers13092155. [PMID: 33947031 PMCID: PMC8124525 DOI: 10.3390/cancers13092155] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/29/2021] [Accepted: 04/01/2021] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND It would be clinically useful to prospectively identify the risk of disease progression in chronic myeloid leukaemia (CML). Overexpression of cancerous inhibitor of protein phosphatase 2A (PP2A) (CIP2A) protein is an adverse prognostic indicator in many cancers. METHODS We examined CIP2A protein levels in diagnostic samples from the SPIRIT2 trial in 172 unselected patients, of whom 90 received imatinib and 82 dasatinib as first-line treatment. RESULTS High CIP2A levels correlated with inferior progression-free survival (p = 0.04) and with worse freedom from progression (p = 0.03), and these effects were confined to dasatinib recipients. High CIP2A levels were associated with a six-fold higher five-year treatment failure rate than low CIP2A levels (41% vs. 7.5%; p = 0.0002), in both imatinib (45% vs. 11%; p = 0.02) and dasatinib recipients (36% vs. 4%; p = 0.007). Imatinib recipients with low CIP2A levels had a greater risk of treatment failure (p = 0.0008). CIP2A levels were independent of Sokal, Hasford, EUTOS (EUropean Treatment and Outcome Study), or EUTOS long-term survival scores (ELTS) or the presence of major route cytogenetic abnormalities. No association was seen between CIP2A levels and time to molecular response or the levels of the CIP2A-related proteins PP2A, SET, SET binding protein 1 (SETBP1), or AKT. CONCLUSIONS These data confirm that high diagnostic CIP2A levels correlate with subsequent disease progression and treatment failure. CIP2A is a simple diagnostic biomarker that may be useful in planning treatment strategies.
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Affiliation(s)
- Richard E. Clark
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3GA, UK; (R.E.C.); (A.A.B.); (G.M.A.); (A.K.H.); (L.S.)
| | - Ammar A. Basabrain
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3GA, UK; (R.E.C.); (A.A.B.); (G.M.A.); (A.K.H.); (L.S.)
| | - Gemma M. Austin
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3GA, UK; (R.E.C.); (A.A.B.); (G.M.A.); (A.K.H.); (L.S.)
| | - Alison K. Holcroft
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3GA, UK; (R.E.C.); (A.A.B.); (G.M.A.); (A.K.H.); (L.S.)
| | - Sandra Loaiza
- John Goldman Centre for Cellular Therapy, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London W12 0HS, UK;
| | - Jane F. Apperley
- Centre for Haematology, Imperial College London at Hammersmith Hospital, London W12 0HS, UK;
| | - Christopher Law
- Technology Directorate, University of Liverpool, Liverpool L69 3GA, UK;
| | - Laura Scott
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3GA, UK; (R.E.C.); (A.A.B.); (G.M.A.); (A.K.H.); (L.S.)
| | - Alexandra D. Parry
- Chester Medical School, University of Chester, Bache Hall, Chester CH2 1BR, UK;
| | - Laura Bonnett
- Department of Biostatistics, University of Liverpool, Liverpool L69 3GA, UK;
| | - Claire M. Lucas
- Department of Molecular and Clinical Cancer Medicine, University of Liverpool, Liverpool L69 3GA, UK; (R.E.C.); (A.A.B.); (G.M.A.); (A.K.H.); (L.S.)
- Chester Medical School, University of Chester, Bache Hall, Chester CH2 1BR, UK;
- Correspondence:
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2,5-Dimethyl Celecoxib Inhibits Proliferation and Cell Cycle and Induces Apoptosis in Glioblastoma by Suppressing CIP2A/PP2A/Akt Signaling Axis. J Mol Neurosci 2021; 71:1703-1713. [PMID: 33400072 DOI: 10.1007/s12031-020-01773-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/09/2020] [Indexed: 01/10/2023]
Abstract
2,5-Dimethyl-celecoxib (DMC) is a close structural analog of the selective COX-2 inhibitor celecoxib that lacks COX-2-inhibitory function. Thus, DMC is a promising drug for anti-tumor. In this study, we evaluated the efficacy and the molecular basis of DMC in the treatment of human glioblastoma multiforme (GBM). DMC inhibited the growth and proliferation of GBM cell lines (LN229, A172, U251, and U87MG) in a dose-dependent manner (P < 0.001). In GBM cells treated with DMC, detection by flow cytometry showed cell cycle arrest, and proteins involved in cell cycle such as P21 were increased. Compared with control group, Annexin-V/PI-staining in DMC-treatment group was increased, indicating that DMC could induce apoptosis in GBM cells. Also, associated proteins including cleaved caspase 3 and cleaved PARP-1 were increased. It was further explored whether DMC blocked cell cycle and induced apoptosis in GBM cells through CIP2A/PP2A/AKT signaling pathway. After treatment of DMC, the phosphorylation of Akt was reduced while the total Akt level was not affected. DMC suppressed the expression of CIP2A in a time-dependent manner, while the CIP2A overexpression group reversed cell cycle and apoptotic protein expression led by DMC. Finally, in a xenograft model in nude mice using LN229 cells, DMC suppressed tumor growth. These findings proved that DMC could block cell cycle and induce apoptosis in GBM cells by suppressing CIP2A/PP2A/Akt signaling axis, which indicated that DMC could be an effective option for GBM treatment.
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Bhowmick S, Roy K, Saha A. Exploring CIP2A modulators using multiple molecular modeling approaches. J Biomol Struct Dyn 2020; 40:1048-1063. [PMID: 32930061 DOI: 10.1080/07391102.2020.1821781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Shovonlal Bhowmick
- Department of Chemical Technology, University of Calcutta, Kolkata, West Bengal, India
| | - Kunal Roy
- Department of Pharmaceutical Technology, Drug Theoretics and Cheminformatics Laboratory, Jadavpur University, Kolkata, West Bengal, India
| | - Achintya Saha
- Department of Chemical Technology, University of Calcutta, Kolkata, West Bengal, India
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8
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Kim SH, Lee WH, Seong D, An JH, Je HU, Nam HY, Kim SY, Kim SW, Han MW. The role of CIP2A as a therapeutic target of rapamycin in radioresistant head and neck cancer with TP53 mutation. Head Neck 2019; 41:3362-3371. [DOI: 10.1002/hed.25868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 06/13/2019] [Accepted: 06/18/2019] [Indexed: 02/06/2023] Open
Affiliation(s)
- Song Hee Kim
- Department of OtolaryngologyUlsan University Hospital, University of Ulsan College of Medicine Ulsan Republic of Korea
| | - Won Hyeok Lee
- Department of OtolaryngologyUlsan University Hospital, University of Ulsan College of Medicine Ulsan Republic of Korea
| | - Daseul Seong
- Department of OtolaryngologyUlsan University Hospital, University of Ulsan College of Medicine Ulsan Republic of Korea
| | - Jae Hee An
- Department of OtolaryngologyUlsan University Hospital, University of Ulsan College of Medicine Ulsan Republic of Korea
| | - Hyoung Uk Je
- Department of Radiation OncologyUlsan University Hospital, University of Ulsan College of Medicine Ulsan Republic of Korea
| | - Hae Yun Nam
- Department of Biochemistry and Molecular BiologyAsan Medical Center, University of Ulsan College of Medicine Seoul Republic of Korea
| | - Sang Yoon Kim
- Department of OtolaryngologyAsan Medical Center, University of Ulsan College of Medicine Seoul Republic of Korea
| | - Seong Who Kim
- Department of Biochemistry and Molecular BiologyAsan Medical Center, University of Ulsan College of Medicine Seoul Republic of Korea
| | - Myung Woul Han
- Department of OtolaryngologyUlsan University Hospital, University of Ulsan College of Medicine Ulsan Republic of Korea
- Department of Otolaryngology‐Head and Neck SurgeryLondon Health Sciences Center, Schulich School of Medicine & Dentistry, Western University London Ontario Canada
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Elgenaidi IS, Spiers JP. Regulation of the phosphoprotein phosphatase 2A system and its modulation during oxidative stress: A potential therapeutic target? Pharmacol Ther 2019; 198:68-89. [PMID: 30797822 DOI: 10.1016/j.pharmthera.2019.02.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 02/15/2019] [Indexed: 02/06/2023]
Abstract
Phosphoprotein phosphatases are of growing interest in the pathophysiology of many diseases and are often the neglected partner of protein kinases. One family member, PP2A, accounts for dephosphorylation of ~55-70% of all serine/threonine phosphosites. Interestingly, dysregulation of kinase signalling is a hallmark of many diseases in which an increase in oxidative stress is also noted. With this in mind, we assess the evidence to support oxidative stress-mediated regulation of the PP2A system In this article, we first present an overview of the PP2A system before providing an analysis of the regulation of PP2A by endogenous inhibitors, post translational modification, and miRNA. Next, a detailed critique of data implicating reactive oxygen species, ischaemia, ischaemia-reperfusion, and hypoxia in regulating the PP2A holoenzyme and associated regulators is presented. Finally, the pharmacological targeting of PP2A, its endogenous inhibitors, and enzymes responsible for its post-translational modification are covered. There is extensive evidence that oxidative stress modulates multiple components of the PP2A system, however, most of the data pertains to the catalytic subunit of PP2A. Irrespective of the underlying aetiology, free radical-mediated attenuation of PP2A activity is an emerging theme. However, in many instances, a dichotomy exists, which requires clarification and mechanistic insight. Nevertheless, this raises the possibility that pharmacological activation of PP2A, either through small molecule activators of PP2A or CIP2A/SET antagonists may be beneficial in modulating the cellular response to oxidative stress. A better understanding of which, will have wide ranging implications for cancer, heart disease and inflammatory conditions.
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Affiliation(s)
- I S Elgenaidi
- Department of Pharmacology and Therapeutics, Trinity College Dublin, Ireland
| | - J P Spiers
- Department of Pharmacology and Therapeutics, Trinity College Dublin, Ireland.
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10
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The role of CIP2A in cancer: A review and update. Biomed Pharmacother 2017; 96:626-633. [DOI: 10.1016/j.biopha.2017.08.146] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 08/01/2017] [Accepted: 08/13/2017] [Indexed: 12/11/2022] Open
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Baldacchino S, Wastall LM, Saliba C, Hughes TA, Scerri C, Berwick A, Speirs V, Hanby AM, Grech G. CIP2A expression predicts recurrences of tamoxifen-treated breast cancer. Tumour Biol 2017; 39:1010428317722064. [PMID: 29034804 DOI: 10.1177/1010428317722064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
CIP2A is emerging as an oncoprotein overexpressed commonly across many tumours and generally correlated with higher tumour grade and therapeutic resistance. CIP2A drives an oncogenic potential through inhibiting protein phosphatase 2A, stabilizing MYC, and promoting epithelial-to-mesenchymal transition, although further biological mechanisms for CIP2A are yet to be defined. CIP2A protein expression was studied by immunohistochemistry in oestrogen receptor-positive primary breast cancers (n = 250) obtained from the Leeds Tissue Bank. In total, 51 cases presented with a relapse or metastasis during adjuvant treatment with tamoxifen and were regarded as tamoxifen resistant. CIP2A expression was scored separately for cytoplasmic, nuclear, or membranous staining, and scores were tested for statistically significant relationships with clinicopathological features. Membranous CIP2A was preferentially expressed in cases who experienced a recurrence during tamoxifen treatment thus predicting a worse overall survival (log rank = 8.357, p = 0.004) and disease-free survival (log rank = 21.766, p < 0.001). Cox multivariate analysis indicates that it is an independent prognostic indicator for overall survival (hazard ratio = 4.310, p = 0.013) and disease-free survival (hazard ratio = 5.449, p = 0.002). In this study, we propose the assessment of membranous CIP2A expression as a potential novel prognostic and predictive indicator for tamoxifen resistance and recurrence within oestrogen receptor-positive breast cancer.
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Affiliation(s)
- Shawn Baldacchino
- 1 Laboratory of Molecular Pathology, Department of Pathology, Faculty of Medicine & Surgery, University of Malta, Msida, Malta
| | - Laura M Wastall
- 2 School of Medicine, University of Leeds, Leeds, UK.,3 Department of Cellular Pathology, St James's University Hospital, Leeds, UK
| | - Christian Saliba
- 4 Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | | | - Christian Scerri
- 5 Department of Physiology & Biochemistry, Faculty of Medicine & Surgery, University of Malta, Msida, Malta
| | - Angelene Berwick
- 6 Leeds Institute of Cancer & Pathology, Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - Valerie Speirs
- 6 Leeds Institute of Cancer & Pathology, Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - Andrew M Hanby
- 3 Department of Cellular Pathology, St James's University Hospital, Leeds, UK.,6 Leeds Institute of Cancer & Pathology, Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - Godfrey Grech
- 1 Laboratory of Molecular Pathology, Department of Pathology, Faculty of Medicine & Surgery, University of Malta, Msida, Malta
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Cip2a promotes cell cycle progression in triple-negative breast cancer cells by regulating the expression and nuclear export of p27Kip1. Oncogene 2016; 36:1952-1964. [DOI: 10.1038/onc.2016.355] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 08/06/2016] [Accepted: 08/19/2016] [Indexed: 01/22/2023]
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13
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Cristóbal I, Madoz-Gúrpide J, Manso R, González-Alonso P, Rojo F, García-Foncillas J. Potential anti-tumor effects of FTY720 associated with PP2A activation: a brief review. Curr Med Res Opin 2016; 32:1137-41. [PMID: 26950691 DOI: 10.1185/03007995.2016.1162774] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
FTY720 (Fingolimod, Gilenya (†) ) is an FDA-approved immunosuppressant currently used in the treatment of multiple sclerosis. However, a large number of studies over the last few years have shown that FTY720 shows potent antitumor properties that suggest its potential usefulness as a novel anticancer agent. Interestingly, the restoration of protein phosphatase 2A (PP2A) activity mediated by FTY720 could play a key role in its antitumor effects. Taking into account that PP2A inactivation is a common event that determines poor outcome in several tumor types, FTY720 could serve as an alternative therapeutic strategy for cancer patients with such alterations.
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Affiliation(s)
- Ion Cristóbal
- a Translational Oncology Division , Oncohealth Institute, IIS-Fundacion Jimenez Diaz-UAM, University Hospital 'Fundacion Jimenez Diaz' , Madrid , Spain
| | | | - Rebeca Manso
- b Pathology Department , IIS 'Fundacion Jimenez Diaz' , Madrid , Spain
| | | | - Federico Rojo
- b Pathology Department , IIS 'Fundacion Jimenez Diaz' , Madrid , Spain
| | - Jesús García-Foncillas
- a Translational Oncology Division , Oncohealth Institute, IIS-Fundacion Jimenez Diaz-UAM, University Hospital 'Fundacion Jimenez Diaz' , Madrid , Spain
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Cancerous Inhibitor of PP2A Silencing Inhibits Proliferation and Promotes Apoptosis in Human Multiple Myeloma Cells. BIOMED RESEARCH INTERNATIONAL 2016; 2016:6864135. [PMID: 27144172 PMCID: PMC4837246 DOI: 10.1155/2016/6864135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/13/2016] [Accepted: 03/20/2016] [Indexed: 12/11/2022]
Abstract
Multiple myeloma is the second most prevalent type of blood cancer, representing approximately 1% of all cancers and 2% of all cancer deaths. There is therefore a strong need to identify critical targets in multiple myeloma neoplasia and progression. Cancerous inhibitor of PP2A (CIP2A) is a human oncoprotein that regulates cancer cell viability and anchorage-independent growth and induces apoptosis. The present study investigated CIP2A function in the human multiple myeloma cell lines RPMI-8226 and NCI-H929 to determine whether it can serve as a potential therapeutic target. CIP2A was silenced in the cells by transfection of short interfering RNA and cell proliferation and apoptosis were evaluated by a tetrazolium salt-based assay and flow cytometry, respectively. CIP2A knockdown inhibited proliferation and induced apoptosis in RPMI-8226 and NCI-H929 cells and decreased the phosphorylation of phosphoinositide 3-kinase (PI3K) p85, AKT1, and mammalian target of rapamycin (mTOR) without affecting total protein levels. Treatment of CIP2A-depletion cells with insulin-like growth factor 1 decreased the effects of CIP2A inhibition on cell viability and apoptosis. These results indicate that CIP2A modulates myeloma cell proliferation and apoptosis via PI3K/AKT/mTOR signaling and suggest that it can potentially serve as a drug target for the treatment of multiple myeloma.
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Sangodkar J, Farrington C, McClinch K, Galsky MD, Kastrinsky DB, Narla G. All roads lead to PP2A: exploiting the therapeutic potential of this phosphatase. FEBS J 2016; 283:1004-24. [PMID: 26507691 PMCID: PMC4803620 DOI: 10.1111/febs.13573] [Citation(s) in RCA: 230] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/29/2015] [Accepted: 10/21/2015] [Indexed: 12/22/2022]
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase involved in the regulation of many cellular processes. A confirmed tumor suppressor protein, PP2A is genetically altered or functionally inactivated in many cancers highlighting a need for its therapeutic reactivation. In this review we discuss recent literature on PP2A: the elucidation of its structure and the functions of its subunits, and the identification of molecular lesions and post-translational modifications leading to its dysregulation in cancer. A final section will discuss the proteins and small molecules that modulate PP2A and how these might be used to target dysregulated forms of PP2A to treat cancers and other diseases.
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Affiliation(s)
- Jaya Sangodkar
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mt. Sinai, New York, NY, USA
| | - Caroline Farrington
- Department of Medicine and Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Kimberly McClinch
- Department of Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Matthew D. Galsky
- Department of Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - David B. Kastrinsky
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Goutham Narla
- Department of Medicine and Institute for Transformative Molecular Medicine, Case Western Reserve University, Cleveland, OH, USA
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16
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Peng B, Chai Y, Li Y, Liu X, Zhang J. CIP2A overexpression induces autoimmune response and enhances JNK signaling pathway in human lung cancer. BMC Cancer 2015; 15:895. [PMID: 26560124 PMCID: PMC4642650 DOI: 10.1186/s12885-015-1899-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 11/03/2015] [Indexed: 01/16/2023] Open
Abstract
Background Cancerous inhibitor of PP2A (CIP2A) is a recently characterized oncoprotein, which promotes cancer cell proliferation. But the role of CIP2A in lung cancer progression is still not well understood. Methods The expression level of CIP2A in lung cancer tissues was examined by immunohistochemistry. CIP2A-associated cell proliferation was performed by knock down or overexpression of CIP2A in lung cancer cells. Phospho-array was used to screen kinase candidates related to expression change of CIP2A. Western-blot and luciferase reporter assay were used to validate phospho-array results. Results Overexpression of CIP2A in lung cancer not only triggers immune response in lung cancer patients but also promotes lung cancer cell proliferation. By phospho-array, several kinase candidates were identified, one of which is c-Jun activated kinases (JNK). The knock down of CIP2A decreased JNK phosphorylation, and the phosphorylation of downstream transcriptional factors, ATF2 and c-Jun, whose transcriptional activity were decreased as well. Furthermore, the expression level of CIP2A also affected the phosphorylation of the upstream kinase of JNK, MKK4/MKK7. At last, treatment with JNK inhibitor partially abolished CIP2A-induced cell proliferation. Conclusion CIP2A is a tumor-associated autoantigen in lung cancer, which promote lung cancer proliferation partially through MKK4/7-JNK signaling pathway.
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Affiliation(s)
- Bo Peng
- Border Biomedical Research Center & Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA.
| | - Yurong Chai
- Border Biomedical Research Center & Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA.
| | - Yang Li
- Border Biomedical Research Center & Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA.
| | - Xinxin Liu
- Border Biomedical Research Center & Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA.
| | - Jianying Zhang
- Border Biomedical Research Center & Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX, 79968, USA.
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Chen KF, Yen CC, Lin JK, Chen WS, Yang SH, Jiang JK, Lan YT, Lin CC, Yu HC, Hsu HM, Lin WL, Teng HW. Cancerous inhibitor of protein phosphatase 2A (CIP2A) is an independent prognostic marker in wild-type KRAS metastatic colorectal cancer after colorectal liver metastasectomy. BMC Cancer 2015; 15:301. [PMID: 25896895 PMCID: PMC4404594 DOI: 10.1186/s12885-015-1300-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 03/31/2015] [Indexed: 01/07/2023] Open
Abstract
Background The impact of KRAS signaling on cancerous inhibitor of protein phosphatase 2A (CIP2A) expression has not yet been explored. We investigated the impact of KRAS on CIP2A expression in colorectal cancer patients after colorectal liver metastasectomy. Methods We examined CIP2A expression by immunohistochemistry (IHC) and used direct sequencing to identify the mutational status of KRAS exon 2 (codon 12 and 13). The association between CIP2A expression, KRAS genotype, clinicopathological parameters and survival were examined by the Kaplan–Meier method and the Cox proportional hazards model. A combination of immunoblotting and proliferation assays were employed to elucidate the role of CIP2A in signal transduction pathways in wild-type KRAS Caco-2 cells. Results A total of 220 colorectal cancer patients who had undergone colorectal liver metastasectomy were included in the study. The mutant KRAS genotype was associated with CIP2A overexpression. CIP2A expression was an independent prognostic marker in patients with wild-type KRAS metastatic colorectal cancer after colorectal liver metastasectomy (relative risk = 1.873, P = 0.019). Targeted silencing of CIP2A in Caco-2 cells (wild-type KRAS) led to decreased expression of pERK/ERK and decreased cell proliferation. Overexpression of mutant KRAS G12D in Caco-2 cells led to an increase in CIP2A expression and cell proliferation. In Caco-2 cells with the KRAS G12D, KRAS overexpression preserved the regulation effect of CIP2A in KRAS and abrogated the impact of CIP2A regulation on pERK/ERK and cell proliferation. CIP2A inhibition also increased the efficacy of cetuximab in Caco-2 cells. Conclusions CIP2A is an independent prognostic marker in patients with wild-type KRAS metastatic colorectal cancer after colorectal liver metastasectomy.
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Affiliation(s)
- Kuen-Feng Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan. .,National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan.
| | - Chueh-Chuan Yen
- Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, No. 201, Section 2, Shih-Pai Road, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Jen-Kou Lin
- Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Wei-Shone Chen
- Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Shung-Haur Yang
- Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Jeng-Kai Jiang
- Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Yuan-Tzu Lan
- Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Chun-Chi Lin
- Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Hui-Chuan Yu
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan. .,National Center of Excellence for Clinical Trial and Research, National Taiwan University Hospital, Taipei, Taiwan.
| | - Hui-Mei Hsu
- Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Wen-Ling Lin
- Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
| | - Hao-Wei Teng
- Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, No. 201, Section 2, Shih-Pai Road, Taipei, Taiwan. .,Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan. .,National Yang-Ming University School of Medicine, Taipei, Taiwan.
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18
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Khanna A, Pimanda JE. Clinical significance of cancerous inhibitor of protein phosphatase 2A in human cancers. Int J Cancer 2015; 138:525-32. [DOI: 10.1002/ijc.29431] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 12/28/2014] [Accepted: 12/29/2014] [Indexed: 01/03/2023]
Affiliation(s)
- Anchit Khanna
- Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales (UNSW) Medicine Department; Sydney New South Wales 2052 Australia
| | - John E. Pimanda
- Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales (UNSW) Medicine Department; Sydney New South Wales 2052 Australia
- Department of Haematology; the Prince of Wales Hospital; Randwick New South Wales Australia
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CIP2A is overexpressed and involved in the pathogenesis of chronic myelocytic leukemia by interacting with breakpoint cluster region-Abelson leukemia virus. Med Oncol 2014; 31:112. [DOI: 10.1007/s12032-014-0112-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 06/30/2014] [Indexed: 01/26/2023]
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20
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De P, Carlson J, Leyland-Jones B, Dey N. Oncogenic nexus of cancerous inhibitor of protein phosphatase 2A (CIP2A): an oncoprotein with many hands. Oncotarget 2014; 5:4581-602. [PMID: 25015035 PMCID: PMC4148086 DOI: 10.18632/oncotarget.2127] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/20/2014] [Indexed: 12/23/2022] Open
Abstract
Oncoprotein CIP2A a Cancerous Inhibitor of PP2A forms an "oncogenic nexus" by virtue of its control on PP2A and MYC stabilization in cancer cells. The expression and prognostic function of CIP2A in different solid tumors including colorectal carcinoma, head and neck cancers, gastric cancers, lung carcinoma, cholangiocarcinoma, esophageal cancers, pancreatic carcinoma, brain cancers, breast carcinoma, bladder cancers, ovarian carcinoma, renal cell carcinomas, tongue cancers, cervical carcinoma, prostate cancers, and oral carcinoma as well as a number of hematological malignancies are just beginning to emerge. Herein, we reviewed the recent progress in our understanding of (1) how an "oncogenic nexus" of CIP2A participates in the tumorigenic transformation of cells and (2) how we can prospect/view the clinical relevance of CIP2A in the context of cancer therapy. The review will try to understand the role of CIP2A (a) as a biomarker in cancers and evaluate the prognostic value of CIP2A in different cancers (b) as a therapeutic target in cancers and (c) in drug response and developing chemo-resistance in cancers.
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Affiliation(s)
- Pradip De
- Department of Molecular & Experimental Medicine, Avera Research Institute, Sioux Falls, SD
- Department of Internal Medicine, SSOM, University of South Dakota, Sioux Falls, SD
| | - Jennifer Carlson
- Department of Molecular & Experimental Medicine, Avera Research Institute, Sioux Falls, SD
| | - Brian Leyland-Jones
- Department of Molecular & Experimental Medicine, Avera Research Institute, Sioux Falls, SD
- Department of Internal Medicine, SSOM, University of South Dakota, Sioux Falls, SD
| | - Nandini Dey
- Department of Molecular & Experimental Medicine, Avera Research Institute, Sioux Falls, SD
- Department of Internal Medicine, SSOM, University of South Dakota, Sioux Falls, SD
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21
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Wei L, Qu W, Sun J, Wang X, Lv L, Xie L, Song X. Knockdown of cancerous inhibitor of protein phosphatase 2A may sensitize NSCLC cells to cisplatin. Cancer Gene Ther 2014; 21:194-9. [PMID: 24874844 DOI: 10.1038/cgt.2014.18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 04/09/2014] [Accepted: 04/09/2014] [Indexed: 11/09/2022]
Abstract
Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a recently identified human oncoprotein that can stabilize some proteins by inhibiting degradation mediated by protein phosphatase 2A (PP2A) and it increases the proliferation of several cancer cells. Recent studies have highlighted a potential role for CIP2A in promoting tumor progression and metastasis. However, whether CIP2A could increase chemoresistance of cancer cells to chemotherapeutic agent cisplatin remains unclear. To determine whether CIP2A serves as a potential therapeutic target of human non-small-cell lung cancer (NSCLC), we utilized small interference RNA (siRNA) to knock down CIP2A expression in human NSCLC cells and analyzed their phenotypic changes. The data demonstrated that CIP2A silencing led to decreased proliferation, impaired clonogenicity and enhanced chemosensitivity and apoptosis to cisplatin in human NSCLC cells, as well as reduced Akt phosphorylation. In addition, overexpression of CIP2A diminished NSCLC cell chemosensitivity to cisplatin by inducing activation of Akt pathway, suggesting critical roles of CIP2A in NSCLC cell chemoresistance to cisplatin and rasing the possibility of CIP2A inhibition as a promising approach for lung cancer therapy.
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Affiliation(s)
- L Wei
- Shandong Provincial Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China
| | - W Qu
- Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China
| | - J Sun
- Department of Pathology, Shandong Cancer Hospital and Institute, Jinan, China
| | - X Wang
- Shandong Provincial Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China
| | - L Lv
- Shandong Provincial Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China
| | - L Xie
- Shandong Provincial Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China
| | - X Song
- Shandong Provincial Key Laboratory of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China
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22
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Laine A, Westermarck J. Molecular pathways: harnessing E2F1 regulation for prosenescence therapy in p53-defective cancer cells. Clin Cancer Res 2014; 20:3644-50. [PMID: 24788101 DOI: 10.1158/1078-0432.ccr-13-1942] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Induction of terminal proliferation arrest, senescence, is important for in vivo tumor-suppressive function of p53. Moreover, p53-mutant cells are highly resistant to senescence induction by either oncogenic signaling during cellular transformation or in response to different therapies. Senescence resistance in p53-mutant cells has been attributed mostly to inhibition of the checkpoint function of p53 in response to senescence-inducing stress signals. Here, we review very recent evidence that offers an alternative explanation for senescence resistance in p53-defective cancer cells: p21-mediated E2F1 expression. We discuss the potential relevance of these findings for senescence-inducing therapies and highlight cyclin-dependent kinases (CDK) and mechanisms downstream of retinoblastoma protein (RB) as prospective prosenescence therapeutic targets. In particular, we discuss recent findings indicating an important role for the E2F1-CIP2A feedback loop in causing senescence resistance in p53-compromised cancer cells. We further propose that targeting of the E2F1-CIP2A feedback loop could provide a prosenescence therapeutic approach that is effective in both p53-deficient and RB-deficient cancer cells, which together constitute the great majority of all cancer cells. Diagnostic evaluation of the described senescence resistance mechanisms in human tumors might also be informative for patient stratification for already existing therapies.
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Affiliation(s)
- Anni Laine
- Authors' Affiliations: Turku Centre for Biotechnology, University of Turku and Åbo Akademi University; and
| | - Jukka Westermarck
- Authors' Affiliations: Turku Centre for Biotechnology, University of Turku and Åbo Akademi University; and Department of Pathology, University of Turku, Turku, Finland
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23
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Choi YA, Koo JS, Park JS, Park MY, Jeong AL, Oh KS, Yang Y. Estradiol enhances CIP2A expression by the activation of p70 S6 kinase. Endocr Relat Cancer 2014; 21:189-202. [PMID: 24280132 DOI: 10.1530/erc-13-0453] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cancerous inhibitor of PP2A (CIP2A) stimulates the proliferation of various cancer cells, and 17β-estradiol (E₂) enhances the proliferation of breast cancer cells. E₂ activates epidermal growth factor receptor (EGFR), stimulating the MEK1/2 and PI3K pathways, and CIP2A expression is increased by the MEK1/2-induced transcription factor ETS1. It is possible for E₂ to increase CIP2A expression. This study examined whether E₂ could increase CIP2A expression and whether CIP2A is highly expressed in estrogen receptor (ER)-positive breast cancer tissues. E₂ increased CIP2A expression at the translational level in a c-MYC-independent manner in MCF-7 cells. E₂-enhanced proliferation was impaired without CIP2A expression. E₂-stimulated EGFR activated the MAPK and PI3K pathways, which converged to activate p70 S6 kinase (S6K). Phosphorylation at all the three phosphorylation sites (S424/T421, T229, and T389) on S6K was required for the phosphorylation of eukaryotic initiation factor 4B (eIF4B), which was responsible for the increase in CIP2A translation. Furthermore, CIP2A expression was higher in ER-positive tissues than in ER-negative tissues. This is the first study, to our knowledge, to demonstrate that CIP2A is a key factor in E₂-enhanced proliferation and that estrogen regulates CIP2A expression by non-genomic action through EGFR.
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Affiliation(s)
- Yeon A Choi
- Department of Life Science, Research Center for Women's Disease, Sookmyung Women's University, Seoul 140-742, Republic of Korea Department of Pathology, Yonsei University College of Medicine, Seoul, South Korea
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24
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Jeong AL, Lee S, Park JS, Han S, Jang CY, Lim JS, Lee MS, Yang Y. Cancerous inhibitor of protein phosphatase 2A (CIP2A) protein is involved in centrosome separation through the regulation of NIMA (never in mitosis gene A)-related kinase 2 (NEK2) protein activity. J Biol Chem 2013; 289:28-40. [PMID: 24214971 DOI: 10.1074/jbc.m113.507954] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cancerous inhibitor of protein phosphatase 2A (CIP2A) is overexpressed in most human cancers and has been described as being involved in the progression of several human malignancies via the inhibition of protein phosphatase 2A (PP2A) activity toward c-Myc. However, with the exception of this role, the cellular function of CIP2A remains poorly understood. On the basis of yeast two-hybrid and coimmunoprecipitation assays, we demonstrate here that NIMA (never in mitosis gene A)-related kinase 2 (NEK2) is a binding partner for CIP2A. CIP2A exhibited dynamic changes in distribution, including the cytoplasm and centrosome, depending on the cell cycle stage. When CIP2A was depleted, centrosome separation and the mitotic spindle dynamics were impaired, resulting in the activation of spindle assembly checkpoint signaling and, ultimately, extension of the cell division time. Our data imply that CIP2A strongly interacts with NEK2 during G2/M phase, thereby enhancing NEK2 kinase activity to facilitate centrosome separation in a PP1- and PP2A-independent manner. In conclusion, CIP2A is involved in cell cycle progression through centrosome separation and mitotic spindle dynamics.
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Affiliation(s)
- Ae Lee Jeong
- From the Research Center for Women's Disease, Department of Life Systems and
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25
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Zhai M, Cong L, Han Y, Tu G. CIP2A is overexpressed in osteosarcoma and regulates cell proliferation and invasion. Tumour Biol 2013; 35:1123-8. [PMID: 24014087 DOI: 10.1007/s13277-013-1150-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 08/26/2013] [Indexed: 12/24/2022] Open
Abstract
Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a newly characterized oncoprotein involved in a variety of malignant tumors. However, its expression pattern and biological functions in osteosarcoma remain unclear. In the present study, CIP2A expression was analyzed in 51 human osteosarcoma specimens using immunohistochemistry. CIP2A siRNA was used in the MG-63 cell line, and the effect of CIP2A depletion on cell proliferation and invasion was evaluated. We found that CIP2A was overexpressed in 76.5 % (39/51) of osteosarcoma tissues, while normal bone tissues showed negative CIP2A expression. In addition, the positive rate of CIP2A expression was higher in stage IIB osteosarcoma than stage IIA cases. Knockdown of the CIP2A expression significantly reduced osteosarcoma cell proliferation and invasion, with decreased c-Myc expression and p-AKT expression. CIP2A depletion also facilitated apoptosis and inhibited MMP9 mRNA expression. Taken together, our data identified CIP2A as a critical oncoprotein involved in cell proliferation and invasion, which could serve as a therapeutic target in osteosarcoma.
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Affiliation(s)
- Mo Zhai
- Department of Orthopaedics, The First Hospital of China Medical University, No. 155 Nanjingbei Street, Heping District, Shenyang, 110001, China
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26
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CIP2A expression and prognostic role in patients with esophageal adenocarcinoma. Med Oncol 2013; 30:684. [PMID: 23925667 DOI: 10.1007/s12032-013-0684-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 07/30/2013] [Indexed: 12/17/2022]
Abstract
CIP2A is overexpressed in many cancers, including esophageal squamous cell carcinoma. The regulation of c-MYC and CIP2A expression is characterized by a positive feedback mechanism facilitating the expression of both of them and accelerating cancer cell proliferation in gastric cancer. Increased CIP2A expression is a predictor of poor survival in some cancers. The incidence of positive CIP2A immunostaining and its association with c-MYC and its predictive value in esophageal adenocarcinoma are unknown. All esophageal adenocarcinoma patients from 1990 to 2007 with sufficient material for analysis of CIP2A and c-MYC in two university hospitals were included in the study. In addition, biopsies from Barrett's epithelium from the cancer patients and control tissue from normal esophageal mucosa adjacent to the tumor were included. CIP2A was moderately or strongly positive in 77.9 %, and c-MYC in 93.8 % of the cancer specimens. These frequencies were statistically different from the expression in normal esophageal epithelium. In addition, there was a positive correlation between CIP2A and c-MYC expression (p = 0.018). According to adjusted Cox regression survival analysis, CIP2A and c-MYC had no effect on survival. However, among patients with stage IVA-IVB cancer, there was a trend toward poor prognosis in CIP2A-positive patients. The expression of CIP2A and c-MYC was associated with each other, and their overexpression was found in most cases of esophageal adenocarcinoma. However, CIP2A and c-MYC had no effect on survival.
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Dai L, Lei N, Liu M, Zhang JY. Autoantibodies to tumor-associated antigens as biomarkers in human hepatocellular carcinoma (HCC). Exp Hematol Oncol 2013; 2:15. [PMID: 23687996 PMCID: PMC3665485 DOI: 10.1186/2162-3619-2-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 05/07/2013] [Indexed: 01/29/2023] Open
Abstract
Tumor-associated antigens (TAAs) recognized by cellular and/or humoral effectors of the immune system are attractive targets for diagnostic and therapeutic approaches to human cancer. Different approaches can be used to comprehensively characterize and validate the identified TAA/anti-TAA systems, which are potential biomarkers in cancer immunodiagnosis. Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. The high fatality rate of HCC within one year after its detection might be partly attributed to a lack of diagnostic methods that enable the early detection. Our previous studies have shown that novel autoantibodies can appear which are not detected prior to pre-malignant conditions during transition from chronic liver disease to HCC. The hypothesis we advance is the transition to malignancy can be associated with autoantibody response to certain cellular proteins that might have some role in tumorigenesis. We propose that the information that the cancer patient’s immune system is conveying in the form of autoantibodies to tumor-associated antigens (TAAs) should be utilized to a greater extent in identifying early signs of tumorigenesis. In this review, we will focus on the important features of TAA and the possibility that autoantibodies to TAAs can be used as biomarkers in immunodiagnosis and prognosis of HCC.
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Affiliation(s)
- Liping Dai
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Ningjing Lei
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Mei Liu
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
| | - Jian-Ying Zhang
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX 79968, USA
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Yi F, Ni W, Liu W, Bai J, Li W. Expression and biological role of CIP2A in human astrocytoma. Mol Med Rep 2013; 7:1376-80. [PMID: 23467938 DOI: 10.3892/mmr.2013.1357] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 02/21/2013] [Indexed: 11/06/2022] Open
Abstract
Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a recently characterized oncoprotein involved in the progression of several human malignancies. The present study aimed to investigate the clinical significance and biological function of CIP2A in astrocytoma. CIP2A expression was analyzed in 135 archived astrocytoma specimens using immunohistochemistry. Of these specimens, 75 cases (55.6%) overexpressed CIP2A. The CIP2A overexpression was observed to be positively correlated with advanced tumor grade (P<0.001). siRNA-mediated knockdown of CIP2A was performed in A172 and U87 cell lines. MTT, colony formation and soft agar colony formation assays and Annexin V/propidium iodide analysis were performed to assess the role of CIP2A in cell proliferation and apoptosis. CIP2A depletion in the astrocytoma cell lines inhibited cell growth, reduced anchorage‑independent cell growth and increased apoptosis. In addition, CIP2A depletion increased caspase‑3 cleavage and downregulated c‑Myc, Bcl‑2 and phospho‑Akt expression. These results validate the role of CIP2A as a clinically relevant oncoprotein and establish CIP2A as a promising therapeutic target of astrocytoma.
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Affiliation(s)
- Fuxin Yi
- Department of Neurosurgery, First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121000, PR China.
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Cancerous inhibitor of protein phosphatase 2A mediates bortezomib-induced autophagy in hepatocellular carcinoma independent of proteasome. PLoS One 2013; 8:e55705. [PMID: 23383345 PMCID: PMC3562236 DOI: 10.1371/journal.pone.0055705] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 12/28/2012] [Indexed: 12/25/2022] Open
Abstract
Previously, we reported that cancerous inhibitor of protein phosphatase 2A (CIP2A) mediates the apoptotic effect of bortezomib in hepatocellular carcinoma (HCC). Here, we report a proteasome-independent mechanism by which bortezomib induces autophagy in HCC. Our data indicate that bortezomib activated autophagy in a dose- and time- dependent manner in HCC cell lines including Huh-7, Sk-Hep1, and Hep3B. Bortezomib downregulated CIP2A, phospho-Akt (P-Akt) and phospho-4EBP1 (P-4EBP1) in a dose- and time-dependent manner in all tested HCC cells. Ectopic expression of CIP2A abolished the effect of bortezomib on autophagy. Co-treatment of bortezomib and calyculin A, a PP2A inhibitor, reduced the effect of bortezomib on P-Akt, P-4EBP1, and autophagy. Increased phosphorylation of either Akt or 4EBP1 by ectopic overexpression protected cells from bortezomib-induced autophagy. Furthermore, we examined the effect of ΔBtz, a bortezomib derivative that closely resembles bortezomib structurally but has no proteasome activity, in HCC. Interestingly, ΔBtz demonstrated similar effects to bortezomib on autophagy, CIP2A, P-Akt and P-4EBP1, suggesting that the effect of bortezomib on autophagy is independent of proteasome inhibition. Moreover, our in vivo data showed that both bortezomib and ΔBtz inhibited tumor growth, downregulated CIP2A, P-Akt and induced autophagy in Huh-7 tumors. In conclusion, bortezomib induces autophagy in HCC through a CIP2A-PP2A-Akt-4EBP1 pathway.
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Xue Y, Wu G, Wang X, Zou X, Zhang G, Xiao R, Yuan Y, Long D, Yang J, Wu Y, Xu H, Liu F, Liu M. CIP2A is a predictor of survival and a novel therapeutic target in bladder urothelial cell carcinoma. Med Oncol 2012; 30:406. [PMID: 23275123 DOI: 10.1007/s12032-012-0406-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 10/05/2012] [Indexed: 11/28/2022]
Abstract
Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a recently identified human oncoprotein that stabilizes the c-MYC protein. Herein, we aimed to investigate its expression pattern, clinical significance, and biological function in urothelial cell carcinoma (UCC) of the bladder. CIP2A expression was examined in 20 fresh bladder UCC tissues and paired adjacent normal bladder tissues by RT-PCR and Western blot. Immunohistochemistry for CIP2A was performed on additional 117 bladder UCC tissues. The clinical significance of CIP2A expression was analyzed. CIP2A downregulation was performed in bladder UCC cell line T24 with high abundance of CIP2A, and the effects of CIP2A silencing on cell proliferation, migration, invasion in vitro, and tumor growth in vivo were evaluated. We found that CIP2A expression was upregulated in bladder UCC tissues relative to adjacent normal bladder tissues. Clinicopathological analysis showed that CIP2A expression was significantly associated with tumor stage (P = 0.004), histological grade (P = 0.007), and lymph node status (P = 0.001). The Kaplan-Meier survival curves revealed that CIP2A expression was associated with poor prognosis in bladder UCC patients (log-rank value = 14.704, P < 0.001). CIP2A expression was an independent prognostic marker of overall patient survival in a multivariate analysis (P = 0.015). Knockdown of the CIP2A expression reduced cell proliferation, anchorage-independent growth, migration, invasion, and tumor growth in xenograft model mice. Our findings suggest that CIP2A is an independent predictor of poor prognosis of bladder UCC patients, and inhibition of its expression might be of therapeutic significance.
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Affiliation(s)
- Yijun Xue
- Department of Urology, First Affiliated Hospital of Gannan Medical University, No. 23, Qing Nian Road, Ganzhou 341000, China
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Pallai R, Bhaskar A, Sodi V, Rice LM. Ets1 and Elk1 transcription factors regulate cancerous inhibitor of protein phosphatase 2A expression in cervical and endometrial carcinoma cells. Transcription 2012; 3:323-35. [PMID: 23117818 DOI: 10.4161/trns.22518] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cancerous inhibitor of protein phosphatase 2A (CIP2A) has been identified as a proto-oncogene that is overexpressed in various types of human cancers. CIP2A acts by inhibiting protein phosphatase 2A-dependent destabilization of c-Myc, resulting in increased cell proliferation. Here, we have characterized the proximal promoter region of the human CIP2A gene in cervical, endometrial and liver carcinoma cells. The 5' flanking minimal proximal promoter of the CIP2A gene consists of putative binding sites for Ets1 and Elk1 in forward and reverse orientations. Here, we show that Ets1 and Elk1 binding is essential for CIP2A basal expression in several urogenital cancer cell lines. Interestingly, both Ets1 and Elk1 are required together for CIP2A expression, as siRNA knockdown of Ets1 and Elk1 together decreased CIP2A gene transcription, whereas knockdown of Ets1 or Elk1 alone had no effect. Moreover, ectopic expression of Ets1 and Elk1 together increased CIP2A expression. To gain physiological significance of the Ets1 and Elk1 regulation we observed, a panel of matched human cervical carcinoma samples was analyzed for the expression of CIP2A and Ets1 and/or Elk1. We found a direct correlation between the levels of CIP2A and the levels of Ets1 and Elk1. Our results suggest that the binding of Ets1 and Elk1 together to the proximal CIP2A promoter is absolutely required for CIP2A expression in cervical, endometrial and liver carcinoma cell lines. Thus, different factors regulate CIP2A expression in a cell-type specific manner. As previous work has shown a requirement for only Ets1 in prostate and gastric carcinomas, our results now indicate that CIP2A regulation is more complex than previously determined.
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Affiliation(s)
- Rajash Pallai
- Department of Cancer Signaling and Cell Cycle, Venenum Biodesign, L.L.C, Hamilton, NJ, USA
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Lin YC, Chen KC, Chen CC, Cheng AL, Chen KF. CIP2A-mediated Akt activation plays a role in bortezomib-induced apoptosis in head and neck squamous cell carcinoma cells. Oral Oncol 2012; 48:585-93. [DOI: 10.1016/j.oraloncology.2012.01.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 01/22/2012] [Accepted: 01/25/2012] [Indexed: 12/27/2022]
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Huang P, Qiu J, You J, Hong J, Li B, Zhou K, Chen G, Yuan Y, Zou R. Expression and prognostic significance of CIP2A mRNA in hepatocellular carcinoma and nontumoral liver tissues. Biomarkers 2012; 17:422-9. [PMID: 22537152 DOI: 10.3109/1354750x.2012.680608] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE This study was undertaken to determine the role of cancerous inhibitor of protein phosphatase 2A (CIP2A) in predicting prognosis of hepatocellular carcinoma (HCC). METHODS CIP2A mRNA level of 136 pairs of tumor and nontumoral liver tissues of HCC patients after hepatectomy were investigated by quantitative real-time reverse transcription polymerase chain reaction. RESULTS Intratumoral CIP2A mRNA was not associated with patients' prognosis. However, nontumoral CIP2A mRNA, which was correlated with lack of tumor encapsulation, poor tumor differentiation, intrahepatic metastasis, and high tumor-node-metastasis stage was an independent risk factor for overall survival and recurrence-free survival. CONCLUSIONS Nontumoral CIP2A mRNA expression might serve as a novel biomarker for HCC patients undergoing resection.
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Affiliation(s)
- Pinzhu Huang
- State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong, China
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Böckelman C, Koskensalo S, Hagström J, Lundin M, Ristimäki A, Haglund C. CIP2A overexpression is associated with c-Myc expression in colorectal cancer. Cancer Biol Ther 2012; 13:289-95. [PMID: 22310977 DOI: 10.4161/cbt.18922] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND To improve the prognostic evaluation of colorectal cancer requires new molecular markers. Cancerous inhibitor of protein phosphatase 2A (CIP2A) serves as an oncoprotein by targeting PP 2A-mediated inhibition of c-Myc. A prognostic role for CIP2A has been demonstrated in gastric, lung and tongue cancers. RESULTS CIP2A was overexpressed in 661 (87.9%) specimens. CIP2A overexpression was associated with tumor differentiation grade (p = 0.014), p53 immunopositivity (p = 0.042), EGFR immunopositivity (p = 0.007) and c-Myc nuclear immunopositivity (p = 0.018). In survival analysis, CIP2A failed to show any prognostic significance (p = 0.270, log-rank test). METHODS 863 consecutive colorectal cancer patients treated at Helsinki University Central Hospital in 1983–2001 were collected with 752 scored successfully for CIP2A immunohistochemical expression from tumor tissue microarrays. Associations with clinicopathologic variables and molecular markers were explored by the chi-square test, and the Kaplan-Meier method served for survival analysis. CONCLUSIONS Overexpression of CIP2A in colorectal cancer patients may be an important step in colorectal carcinogenesis. Based on our findings, CIP2A shows no association with patient prognosis in colorectal cancer, but is associated with nuclear c-Myc.
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Affiliation(s)
- Camilla Böckelman
- Genome-Scale Biology Research Program, Biomedicum Helsinki, Helsinki, Finland
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Niemelä M, Kauko O, Sihto H, Mpindi JP, Nicorici D, Pernilä P, Kallioniemi OP, Joensuu H, Hautaniemi S, Westermarck J. CIP2A signature reveals the MYC dependency of CIP2A-regulated phenotypes and its clinical association with breast cancer subtypes. Oncogene 2012; 31:4266-78. [DOI: 10.1038/onc.2011.599] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Bortezomib enhances radiation-induced apoptosis in solid tumors by inhibiting CIP2A. Cancer Lett 2011; 317:9-15. [PMID: 22085493 DOI: 10.1016/j.canlet.2011.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 10/27/2011] [Accepted: 11/02/2011] [Indexed: 01/28/2023]
Abstract
Previously, we demonstrated that cancerous inhibitor of protein phosphatase 2A (CIP2A) mediates bortezomib-induced apoptosis in hepatocellular carcinoma cells. Herein, we report that bortezomib sensitizes solid tumor cells to radiation-induced apoptosis. Treatment with a combination of bortezomib and radiation downregulated CIP2A in a dose-dependent manner in solid tumor cells. Knockdown of CIP2A enhanced radiation-induced apoptosis in cancer cells, and ectopic expression of CIP2A in cancer cells abolished radiation-induced apoptosis. Finally, our in vivo data showed that bortezomib and radiation combination treatment decreased tumor growth significantly. Thus, bortezomib sensitized solid tumor cells to radiation through the inhibition of CIP2A.
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Expression of CIP2A in renal cell carcinomas correlates with tumour invasion, metastasis and patients' survival. Br J Cancer 2011; 105:1905-11. [PMID: 22075943 PMCID: PMC3251889 DOI: 10.1038/bjc.2011.492] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Background: Cancerous inhibitor of protein phosphatase 2A (CIP2A) drives cellular transformation. The objective of this study was to detect the potential effects of CIP2A in renal cell carcinomas (RCCs). Methods: A total of 107 RCC patients were involved in the study. Cancerous inhibitor of protein phosphatase 2A expression was investigated by real-time PCR and immunohistochemistry. In vitro, we examined the expression of CIP2A and c-Myc and tested the migration and invasion capability of A498 and KRC/Y cells with scratch migration assay and Matrigel invasion assay after down-regulating CIP2A expression using siRNA. Results: Cancerous inhibitor of protein phosphatase 2A was over-expressed in RCC tissues. Clear cell RCC showed an even higher-CIP2A expression level than papillary or chromophobe RCC did. The CIP2A immunostaining level was positively correlated with primary tumour stage, lymph node metastasis, distant metastasis, TNM stage and histological grade (all P<0.05). High-CIP2A expression implied poor survival for patients (P<0.05). Cancerous inhibitor of protein phosphatase 2A depletion by siRNA down-regulated c-Myc expression and attenuated the migration and invasion of RCC cells. Conclusion: Higher-CIP2A expression positively correlates with the aggressive phenotype of RCCs, and predicts poor prognosis for patients. Cancerous inhibitor of protein phosphatase 2A may be a novel target for prevention and treatment of RCC metastasis and recurrence.
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Overexpression and small molecule-triggered downregulation of CIP2A in lung cancer. PLoS One 2011; 6:e20159. [PMID: 21655278 PMCID: PMC3105001 DOI: 10.1371/journal.pone.0020159] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 04/12/2011] [Indexed: 11/19/2022] Open
Abstract
Background Lung cancer is the leading cause of cancer deaths worldwide, with a five-year overall survival rate of only 15%. Cancerous inhibitor of PP2A (CIP2A) is a human oncoprotein inhibiting PP2A in many human malignancies. However, whether CIP2A can be a new drug target for lung cancer is largely unclear. Methodology/Principal Findings Normal and malignant lung tissues were derived from 60 lung cancer patients from southern China. RT-PCR, Western blotting and immunohistochemistry were used to evaluate the expression of CIP2A. We found that among the 60 patients, CIP2A was undetectable or very low in paratumor normal tissues, but was dramatically elevated in tumor samples in 38 (63.3%) patients. CIP2A overexpression was associated with cigarette smoking. Silencing CIP2A by siRNA inhibited the proliferation and clonogenic activity of lung cancer cells. Intriguingly, we found a natural compound, rabdocoetsin B which is extracted from a Traditional Chinese Medicinal herb Rabdosia coetsa, could induce down-regulation of CIP2A and inactivation of Akt pathway, and inhibit proliferation and induce apoptosis in a variety of lung cancer cells. Conclusions/Significance Our findings strongly indicate that CIP2A could be an effective target for lung cancer drug development, and the therapeutic potentials of CIP2A-targeting agents warrant further investigation.
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Böckelman C, Hagström J, Mäkinen LK, Keski-Säntti H, Häyry V, Lundin J, Atula T, Ristimäki A, Haglund C. High CIP2A immunoreactivity is an independent prognostic indicator in early-stage tongue cancer. Br J Cancer 2011; 104:1890-5. [PMID: 21610708 PMCID: PMC3111200 DOI: 10.1038/bjc.2011.167] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND No reliable prognostic markers exist for squamous cell carcinoma of the tongue, and its prognosis can even in early stages be unpredictable and survival poor despite treatment. A potential marker is oncoprotein cancerous inhibitor of PP2A (CIP2A), which acts as a prognostic marker in gastric and non-small cell lung cancers. METHODS We collected specimens of 73 stage T1N0M0 and T2N0M0 oral squamous cell carcinomas of the tongue, as well as samples from normal oral mucosa, dysplastic lesions, and invasive carcinomas (n=39). All samples were stained for CIP2A by immunohistochemistry. Survival curves were constructed according to the Kaplan-Meier method. The Cox proportional hazard model served for univariate and multivariate survival analysis. RESULTS High CIP2A immunoreactivity predicted poor survival in tongue cancer patients (P=0.027, logrank test). In multivariate survival analysis, CIP2A was an independent prognostic factor (HR 2.02, 95% confidence interval 1.07-3.82, P=0.030). Cytoplasmic CIP2A expression was higher in severe dysplasia than in mild dysplasia. CONCLUSION Our results suggest that high CIP2A expression characterises aggressive disease. Acting as a prognostic marker it might be of help when choosing patients for adjuvant treatment in tongue cancer patients.
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Affiliation(s)
- C Böckelman
- Genome-Scale Biology Research Program, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, 00014 Helsinki, Finland
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