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Cristóbal I, Rubio J, Santos A, Torrejón B, Caramés C, Imedio L, Mariblanca S, Luque M, Sanz-Alvarez M, Zazo S, Madoz-Gúrpide J, Rojo F, García-Foncillas J. MicroRNA-199b Downregulation Confers Resistance to 5-Fluorouracil Treatment and Predicts Poor Outcome and Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer Patients. Cancers (Basel) 2020; 12:cancers12061655. [PMID: 32580513 PMCID: PMC7352382 DOI: 10.3390/cancers12061655] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/18/2020] [Accepted: 06/18/2020] [Indexed: 12/17/2022] Open
Abstract
Neoadjuvant 5-fluorouracil (5-FU)-based chemoradiotherapy followed by mesorectal excision is the current standard treatment in locally advanced rectal cancer (LARC) and the lack of complete response represents a major problem that compromises long-term patient survival. However, there is a lack of robust established markers predictive of response to this preoperative treatment available in the clinical routine. The tumor suppressor microRNA (miR)-199b directly targets the PP2A inhibitor SET, which has been involved in 5-FU resistance, and its downregulation has been found to correlate with poor outcome in metastatic colorectal cancer. Here, we studied the functional effects of miR-199b on 5-FU sensitivity after its ectopic modulation, and its expression was quantified by real-time-PCR in a cohort of 110 LARC patients to evaluate its potential clinical significance. Interestingly, our findings demonstrate that miR-199b enhances the sensitivity of colorectal cancer cells to 5-FU in a SET-dependent manner, and that both miR-199b overexpression and SET inhibition are able to overcome resistance to this drug using an acquired 5-FU-resistant model. MiR-199b was found downregulated in 26.4% of cases and was associated with positive lymph node levels after chemoradiotherapy (CRT, p = 0.007) and high pathological stage (p = 0.029). Moreover, miR-199b downregulation determined shorter overall (p = 0.003) and event-free survival (p = 0.005), and was an independent predictor of poor response to preoperative CRT (p = 0.004). In conclusion, our findings highlight the clinical impact of miR-199b downregulation predicting poor outcome and pathological response in LARC, and suggest the miR-199b/SET signaling axis as a novel molecular target to prevent the development of resistance to 5-FU treatment.
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Affiliation(s)
- Ion Cristóbal
- Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS- Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (J.R.); (A.S.); (B.T.); (C.C.); (L.I.); (S.M.)
- Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain
- Correspondence: (I.C.); (J.G.-F.); Tel.: +34-915504800 (I.C. & J.G.-F.)
| | - Jaime Rubio
- Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS- Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (J.R.); (A.S.); (B.T.); (C.C.); (L.I.); (S.M.)
- Medical Oncology Department, University Hospital “Fundación Jiménez Díaz”, UAM, E-28040 Madrid, Spain
| | - Andrea Santos
- Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS- Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (J.R.); (A.S.); (B.T.); (C.C.); (L.I.); (S.M.)
- Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain
| | - Blanca Torrejón
- Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS- Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (J.R.); (A.S.); (B.T.); (C.C.); (L.I.); (S.M.)
- Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain
| | - Cristina Caramés
- Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS- Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (J.R.); (A.S.); (B.T.); (C.C.); (L.I.); (S.M.)
- Medical Oncology Department, University Hospital “Fundación Jiménez Díaz”, UAM, E-28040 Madrid, Spain
| | - Laura Imedio
- Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS- Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (J.R.); (A.S.); (B.T.); (C.C.); (L.I.); (S.M.)
- Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain
| | - Sofía Mariblanca
- Cancer Unit for Research on Novel Therapeutic Targets, Oncohealth Institute, IIS- Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (J.R.); (A.S.); (B.T.); (C.C.); (L.I.); (S.M.)
- Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain
| | - Melani Luque
- Pathology Department, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (M.L.); (M.S.-A.); (S.Z.); (J.M.-G.); (F.R.)
| | - Marta Sanz-Alvarez
- Pathology Department, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (M.L.); (M.S.-A.); (S.Z.); (J.M.-G.); (F.R.)
| | - Sandra Zazo
- Pathology Department, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (M.L.); (M.S.-A.); (S.Z.); (J.M.-G.); (F.R.)
| | - Juan Madoz-Gúrpide
- Pathology Department, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (M.L.); (M.S.-A.); (S.Z.); (J.M.-G.); (F.R.)
| | - Federico Rojo
- Pathology Department, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain; (M.L.); (M.S.-A.); (S.Z.); (J.M.-G.); (F.R.)
| | - Jesús García-Foncillas
- Translational Oncology Division, Oncohealth Institute, IIS-Fundación Jiménez Díaz-UAM, E-28040 Madrid, Spain
- Medical Oncology Department, University Hospital “Fundación Jiménez Díaz”, UAM, E-28040 Madrid, Spain
- Correspondence: (I.C.); (J.G.-F.); Tel.: +34-915504800 (I.C. & J.G.-F.)
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Protein Phosphatase 2A Inhibiting β-Catenin Phosphorylation Contributes Critically to the Anti-renal Interstitial Fibrotic Effect of Norcantharidin. Inflammation 2020; 43:878-891. [DOI: 10.1007/s10753-019-01173-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Deregulation of SET is Associated with Tumor Progression and Predicts Adverse Outcome in Patients with Early-Stage Colorectal Cancer. J Clin Med 2019; 8:jcm8030346. [PMID: 30871013 PMCID: PMC6463201 DOI: 10.3390/jcm8030346] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 12/26/2022] Open
Abstract
SET nuclear proto-oncogene (SET) deregulation is a novel molecular target in metastatic colorectal cancer (CRC). However, its role in CRC progression and its potential clinical impact in early-stage CRC patients remain unknown. Here, we studied the biological effects of SET on migration using wound-healing and transwell assays, and anchorage-independent cell growth using soft agar colony formation assays after ectopic SET modulation. SET was analyzed by immuno-staining in 231 early-stage CRC patients, and miR-199b expression was quantified by real-time PCR in a set of CRC patients. Interestingly, SET enhances cell migration, markedly affects the colony-forming ability, promotes epithelial to mesenchymal transition, and induces the expression of the MYC proto-oncogene (c-MYC) in CRC cells. SET overexpression was detected in 15.4% of cases and was associated with worse Eastern Cooperative Oncology Group (ECOG) status (p = 0.021) and relapse in stage-II CRC patients (p = 0.008). Moreover, SET overexpression predicted shorter overall survival (p < 0.001) and time to metastasis (p < 0.001), and its prognostic value was particularly evident in elderly patients. MiR-199b downregulation was identified as a molecular mechanism to deregulate SET in patients with localized disease. In conclusion, SET overexpression is a common alteration in early-stage CRC, playing an oncogenic role associated with progression and aggressiveness, and portends a poor outcome. Thus, SET emerges as a novel potential molecular target with clinical impact in early-stage in CRC.
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Downregulation of microRNA-199b predicts unfavorable prognosis and emerges as a novel therapeutic target which contributes to PP2A inhibition in metastatic colorectal cancer. Oncotarget 2018; 8:40169-40180. [PMID: 27517624 PMCID: PMC5522310 DOI: 10.18632/oncotarget.11174] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 07/17/2016] [Indexed: 01/09/2023] Open
Abstract
The tumor suppressor microRNA-199b (miR-199b) is a negative SET regulator associated with poor outcome in some human cancers. However, its expression levels as well as potential biological and clinical significance in colorectal cancer (CRC) remain completely unexplored. The PP2A inhibitor SET has shown promising therapeutic and clinical implications in metastatic CRC (mCRC) but the molecular mechanisms underlying SET deregulation are currently unknown. We show here miR-199b downregulation in 4 out of 5 CRC SET-overexpressing cell lines and its inverse correlation with SET overexpression in CRC patients. Moreover, miR-199b led to PP2A activation through a direct SET inhibition, impaired cell viability and enhanced oxaliplatin sensitivity in CRC cells. MiR-199b was found downregulated in 25% of cases, and associated with lymph metastasis (p = 0.049), presence of synchronous metastasis at diagnosis (p = 0.026) and SET overexpression (p < 0.001). Furthermore, low miR-199b levels determined shorter overall (p < 0.001), progression-free survival (p = 0.003) and predicted clinical benefit to oxaliplatin treatment. The miR-199b prognostic impact was particularly evident in both younger and KRAS wild-type subgroups. Multivariate analyses confirmed its independent prognostic impact. Altogether, our results show that miR-199b is a tumor suppressor whose downregulation independently determines worse outcome and emerges as a potential contributing mechanism to inhibit PP2A via SET overexpression in a subgroup of mCRC patients.
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Lange L, Marks M, Liu J, Wittler L, Bauer H, Piehl S, Bläß G, Timmermann B, Herrmann BG. Patterning and gastrulation defects caused by the tw18 lethal are due to loss of Ppp2r1a. Biol Open 2017; 6:752-764. [PMID: 28619992 PMCID: PMC5483016 DOI: 10.1242/bio.023200] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The mouse t haplotype, a variant 20 cM genomic region on Chromosome 17, harbors 16 embryonic control genes identified by recessive lethal mutations isolated from wild mouse populations. Due to technical constraints so far only one of these, the tw5 lethal, has been cloned and molecularly characterized. Here we report the molecular isolation of the tw18 lethal. Embryos carrying the tw18 lethal die from major gastrulation defects commencing with primitive streak formation at E6.5. We have used transcriptome and marker gene analyses to describe the molecular etiology of the tw18 phenotype. We show that both WNT and Nodal signal transduction are impaired in the mutant epiblast, causing embryonic patterning defects and failure of primitive streak and mesoderm formation. By using a candidate gene approach, gene knockout by homologous recombination and genetic rescue, we have identified the gene causing the tw18 phenotype as Ppp2r1a, encoding the PP2A scaffolding subunit PR65alpha. Our work highlights the importance of phosphatase 2A in embryonic patterning, primitive streak formation, gastrulation, and mesoderm formation downstream of WNT and Nodal signaling.
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Affiliation(s)
- Lisette Lange
- Max Planck Institute for Molecular Genetics, Department Developmental Genetics, Ihnestraße 63-73, Berlin 14195, Germany.,Free University Berlin, Department of Biology, Chemistry and Pharmacy, Takustrasse 3, Berlin 14195, Germany
| | - Matthias Marks
- Max Planck Institute for Molecular Genetics, Department Developmental Genetics, Ihnestraße 63-73, Berlin 14195, Germany
| | - Jinhua Liu
- Max Planck Institute for Molecular Genetics, Department Developmental Genetics, Ihnestraße 63-73, Berlin 14195, Germany
| | - Lars Wittler
- Max Planck Institute for Molecular Genetics, Department Developmental Genetics, Ihnestraße 63-73, Berlin 14195, Germany
| | - Hermann Bauer
- Max Planck Institute for Molecular Genetics, Department Developmental Genetics, Ihnestraße 63-73, Berlin 14195, Germany
| | - Sandra Piehl
- Max Planck Institute for Molecular Genetics, Department Developmental Genetics, Ihnestraße 63-73, Berlin 14195, Germany
| | - Gabriele Bläß
- Max Planck Institute for Molecular Genetics, Department Developmental Genetics, Ihnestraße 63-73, Berlin 14195, Germany
| | - Bernd Timmermann
- Max Planck Institute for Molecular Genetics, Sequencing Core Facility, Ihnestraße 63-73, Berlin 14195, Germany
| | - Bernhard G Herrmann
- Max Planck Institute for Molecular Genetics, Department Developmental Genetics, Ihnestraße 63-73, Berlin 14195, Germany .,Charité-University Medicine Berlin, Institute for Medical Genetics, Campus Benjamin Franklin, Hindenburgdamm 30, Berlin 12203, Germany
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6
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Rauschenberger V, Bernkopf DB, Krenn S, Jalal K, Heller J, Behrens J, Gentzel M, Schambony A. The phosphatase Pgam5 antagonizes Wnt/β-Catenin signaling in embryonic anterior-posterior axis patterning. Development 2017; 144:2234-2247. [PMID: 28506997 DOI: 10.1242/dev.144477] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 05/03/2017] [Indexed: 12/13/2022]
Abstract
The scaffold protein Dishevelled is a central intracellular component of Wnt signaling pathways. Various kinases have been described that regulate and modulate Wnt signaling through phosphorylation of Dishevelled. However, besides general protein phosphatases 1 and 2 (PP1 and PP2), no specific protein phosphatases have been identified. Here, we report on the identification and functional characterization of the protein phosphatase Pgam5 in vitro and in vivo in Xenopus Pgam5 is a novel antagonist of Wnt/β-Catenin signaling in human cells and Xenopus embryogenesis. In early development, Pgam5 is essential for head formation, and for establishing and maintaining the Wnt/β-Catenin signaling gradient that patterns the anterior-posterior body axis. Inhibition of Wnt/β-Catenin signaling and developmental function depend on Pgam5 phosphatase activity. We show that Pgam5 interacts with Dishevelled2 and that Dishevelled2 is a substrate of Pgam5. Pgam5 mediates a marked decrease in Dishevelled2 phosphorylation in the cytoplasm and in the nucleus, as well as decreased interaction between Dishevelled2, Tcf1 and β-Catenin, indicating that Pgam5 regulates Dishevelled function upstream and downstream of β-Catenin stabilization.
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Affiliation(s)
- Verena Rauschenberger
- Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Dominic B Bernkopf
- Experimental Medicine II, Nikolaus-Fiebiger-Centre, Friedrich-Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Sabrina Krenn
- Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Kowcee Jalal
- Experimental Medicine II, Nikolaus-Fiebiger-Centre, Friedrich-Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Jens Heller
- Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
| | - Jürgen Behrens
- Experimental Medicine II, Nikolaus-Fiebiger-Centre, Friedrich-Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Marc Gentzel
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.,Center for Molecular and Cellular Bioengineering, Molecular Analysis - Mass Spectrometry, TU Dresden, 01307 Dresden, Germany
| | - Alexandra Schambony
- Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058 Erlangen, Germany
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7
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Ito T, Ozaki S, Chanasong R, Mizutani Y, Oyama T, Sakurai H, Matsumoto I, Takemura H, Kawahara E. Activation of ERK/IER3/PP2A-B56γ-positive feedback loop in lung adenocarcinoma by allelic deletion of B56γ gene. Oncol Rep 2016; 35:2635-42. [PMID: 26986830 DOI: 10.3892/or.2016.4677] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 12/27/2015] [Indexed: 11/06/2022] Open
Abstract
In order to investigate the involvement of the IER3/PP2A-B56γ/ERK-positive feedback loop, which leads to sustained phosphorylation/activation of ERK in carcinogenesis, we immunohistochemically examined the expression of IER3 and phosphorylated ERK in lung tumor tissues. IER3 was overexpressed in all cases of adenocarcinomas examined, but was not overexpressed in squamous cell carcinomas. Phosphorylated ERK (pERK) was also overexpressed in almost all adenocarcinomas. EGFR and RAS, whose gene product is located upstream of ERK, were sequenced. Activating mutation of EGFR, which is a possible cause of overexpression of IER3 and pERK, was found only in 5 adenocarcinomas (42%). No mutation of RAS was found. We further examined the sequences of all exons of B56γ gene (PPP2R5C) and IER3, but no mutation was found. Using a single nucleotide insertion in intron 1 of PPP2R5C, which was found in the process of sequencing, allelic deletion of PPP2R5C was examined. Eight cases were informative (67%), and the deletion was found in 4 of them (50%). Three cases having deletion of PPP2R5C did not have EGFR mutation. Finally, PPP2R5C deletion or EGFR mutation that could be responsible for IER3/pERK overexpression was found in at least 8 cases (67% or more). This is the first report of a high incidence of deletion of PPP2R5C in human carcinomas.
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Affiliation(s)
- Tomoko Ito
- Department of Thoracic, Cardiovascular and General Surgery, Graduate School of Medical Sciences, Kanazawa University, Kanazawa 920-8640, Japan
| | - Satoru Ozaki
- Department of Clinical Laboratory Medicine, Graduate School of Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
| | - Rachanee Chanasong
- Department of Anatomy, Faculty of Medical Sciences, Naresuan University, Phitsanulok 65000, Thailand
| | - Yuki Mizutani
- Department of Clinical Laboratory Medicine, Graduate School of Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
| | - Takeru Oyama
- Department of Pathology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa 920-8640, Japan
| | - Hiroshi Sakurai
- Department of Clinical Laboratory Medicine, Graduate School of Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
| | - Isao Matsumoto
- Department of Thoracic, Cardiovascular and General Surgery, Graduate School of Medical Sciences, Kanazawa University, Kanazawa 920-8640, Japan
| | - Hirofumi Takemura
- Department of Thoracic, Cardiovascular and General Surgery, Graduate School of Medical Sciences, Kanazawa University, Kanazawa 920-8640, Japan
| | - Ei Kawahara
- Department of Clinical Laboratory Medicine, Graduate School of Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
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Li J, Wang SW, Zhang DS, Sun Y, Zhu CY, Fei Q, Hu J, Zhang C, Sun YM. FTY720-induced enhancement of autophagy protects cells from FTY720 cytotoxicity in colorectal cancer. Oncol Rep 2016; 35:2833-42. [PMID: 26985637 DOI: 10.3892/or.2016.4668] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 02/01/2016] [Indexed: 11/05/2022] Open
Abstract
FTY720, also known as fingolimod, is a widely used immunomodulator in multiple sclerosis and multiple organ transplantation. It is also an important protein phosphatase 2A (PP2A) activator. Based on this, a number of studies have recently demonstrated the cytotoxic effect of FTY720 in various cancers. Yet in colorectal cancer (CRC), the underlying mechanisms of FTY720 cytotoxicity remain less clear, especially the relationship between a drug and autophagy. We demonstrate here for the first time that FTY720 promotes the appearance of autophagic hallmarks such as autophagosome formation and light chain 3 (LC3)-II accumulation, indicating the participation of autophagy in FTY720 cytotoxicity on CRC. Moreover, inhibition of autophagy using 3-methyladenine (3-MA), a specific inhibitor of autophagy, enhanced FTY720 cytotoxicity, indicating the protective role of autophagy against the drug's own cytotoxic effect. The protective autophagy was likely affected by cancerous inhibitor of PP2A (CIP2A), an endogenous PP2A inhibitor that is closely related with poor prognosis and drug resistance. Consequently, our data not only demonstrate a new mechanism underlying the cytotoxic effect of FTY720 in CRC, but also a new strategy for CRC treatment, especially in cases resistant to conventional chemotherapies because of high CIP2A levels.
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Affiliation(s)
- Juan Li
- Department of Colorectal Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Shu-Wei Wang
- Department of General Surgery, Wuxi Affiliated Hospital of Nanjing University of Chinese Medicine, Wuxi, P.R. China
| | - Dong-Sheng Zhang
- Department of Colorectal Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Ye Sun
- Department of Colorectal Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Chun-Yan Zhu
- Department of Colorectal Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Qiang Fei
- Department of Colorectal Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Jun Hu
- Department of Hepatobiliary Surgery, First People's Hospital of Changzhou, Changzhou, Jiangsu 214000, P.R. China
| | - Chuan Zhang
- Department of Colorectal Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Yue-Ming Sun
- Department of Colorectal Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
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Hong CS, Ho W, Zhang C, Yang C, Elder JB, Zhuang Z. LB100, a small molecule inhibitor of PP2A with potent chemo- and radio-sensitizing potential. Cancer Biol Ther 2015; 16:821-33. [PMID: 25897893 DOI: 10.1080/15384047.2015.1040961] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase that plays a significant role in mitotic progression and cellular responses to DNA damage. While traditionally viewed as a tumor suppressor, inhibition of PP2A has recently come to attention as a novel therapeutic means of driving senescent cancer cells into mitosis and promoting cell death via mitotic catastrophe. These findings have been corroborated in numerous studies utilizing naturally produced compounds that selectively inhibit PP2A. To overcome the known human toxicities associated with these compounds, a water-soluble small molecule inhibitor, LB100, was recently developed to competitively inhibit the PP2A protein. This review summarizes the pre-clinical studies to date that have demonstrated the anti-cancer activity of LB100 via its chemo- and radio-sensitizing properties. These studies demonstrate the tremendous therapeutic potential of LB100 in a variety of cancer types. The results of an ongoing phase 1 trial are eagerly anticipated.
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Key Words
- ABC, ATP-binding cassette.
- APC, adenomatous polyposis coli
- ARPP19, cyclic AMP-regulated phosphoprotein 19
- ATM, ataxia-telangiectasia mutated
- CIP2A, cancerous inhibitor of PP2A
- CNTF, ciliary neurotrophic factor
- DISC, death-inducing signaling complex
- DVL, dishevelled
- ENSA, α-endosulphine
- GBM, glioblastoma
- GFAP, glial fibrillary acidic protein
- HCC, hepatocellular carcinoma
- HDACs, histone deacetylase complexes
- HIF-1a, hypoxia-inducible factor-1a
- HRR, homologous recombination repair
- MDM2, mouse double minute 2 homolog
- MRI, magnetic resonance imaging
- NPC, nasopharyngeal carcinoma
- PP2A, protein phosphatase 2A
- Plk1, polo-like kinase 1
- TCTP, translationally-controlled tumor protein
- TMZ, temozolomide
- TRAIL, TNF-related apoptosis-inducing ligand
- VEGF, vascular endothelial growth factor
- cell cycle
- chemosensitization
- mitotic catastrophe
- protein phosphatase 2A
- radiosensitizationreview
- small molecule inhibitor
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Affiliation(s)
- Christopher S Hong
- a The Ohio State University Wexner Medical Center ; Department of Neurological Surgery ; Columbus , OH USA
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