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Kwanten B, Deconick T, Walker C, Wang F, Landesman Y, Daelemans D. E3 ubiquitin ligase ASB8 promotes selinexor-induced proteasomal degradation of XPO1. Biomed Pharmacother 2023; 160:114305. [PMID: 36731340 DOI: 10.1016/j.biopha.2023.114305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 02/04/2023] Open
Abstract
Selinexor (KPT-330), a small-molecule inhibitor of exportin-1 (XPO1, CRM1) with potent anticancer activity, has recently been granted FDA approval for treatment of relapsed/refractory multiple myeloma and diffuse large B-cell lymphoma (DLBCL), with a number of additional indications currently under clinical investigation. Since selinexor has often demonstrated synergy when used in combination with other drugs, notably bortezomib and dexamethasone, a more comprehensive approach to uncover new beneficial interactions would be of great value. Moreover, stratifying patients, personalizing therapeutics and improving clinical outcomes requires a better understanding of the genetic vulnerabilities and resistance mechanisms underlying drug response. Here, we used CRISPR-Cas9 loss-of-function chemogenetic screening to identify drug-gene interactions with selinexor in chronic myeloid leukemia, multiple myeloma and DLBCL cell lines. We identified the TGFβ-SMAD4 pathway as an important mediator of resistance to selinexor in multiple myeloma cells. Moreover, higher activity of this pathway correlated with prolonged progression-free survival in multiple myeloma patients treated with selinexor, indicating that the TGFβ-SMAD4 pathway is a potential biomarker predictive of therapeutic outcome. In addition, we identified ASB8 (ankyrin repeat and SOCS box containing 8) as a shared modulator of selinexor sensitivity across all tested cancer types, with both ASB8 knockout and overexpression resulting in selinexor hypersensitivity. Mechanistically, we showed that ASB8 promotes selinexor-induced proteasomal degradation of XPO1. This study provides insight into the genetic factors that influence response to selinexor treatment and could support both the development of predictive biomarkers as well as new drug combinations.
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Affiliation(s)
- Bert Kwanten
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy (Rega Institute), Leuven, Belgium
| | - Tine Deconick
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy (Rega Institute), Leuven, Belgium
| | | | - Feng Wang
- Karyopharm Therapeutics, Newton, MA 02459, USA
| | | | - Dirk Daelemans
- KU Leuven Department of Microbiology, Immunology and Transplantation, Laboratory of Virology and Chemotherapy (Rega Institute), Leuven, Belgium.
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2
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Carrà G, Russo I, Guerrasio A, Morotti A. Nuclear-cytoplasmic Shuttling in Chronic Myeloid Leukemia: Implications in Leukemia Maintenance and Therapy. Cells 2019; 8:E1248. [PMID: 31614958 PMCID: PMC6830087 DOI: 10.3390/cells8101248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/10/2019] [Accepted: 10/11/2019] [Indexed: 01/09/2023] Open
Abstract
Nuclear-cytoplasmic shuttling is a highly regulated and complex process, which involves both proteins and nucleic acids. Changes in cellular compartmentalization of various proteins, including oncogenes and tumor suppressors, affect cellular behavior, promoting or inhibiting proliferation, apoptosis and sensitivity to therapies. In this review, we will recapitulate the role of various shuttling components in Chronic Myeloid Leukemia and we will provide insights on the potential role of shuttling proteins as therapeutic targets.
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Affiliation(s)
- Giovanna Carrà
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, 10043 Orbassano (Turin), Italy.
| | - Isabella Russo
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, 10043 Orbassano (Turin), Italy.
| | - Angelo Guerrasio
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, 10043 Orbassano (Turin), Italy.
| | - Alessandro Morotti
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, 10043 Orbassano (Turin), Italy.
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3
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Chen D, Wu D, Shao K, Ye B, Huang J, Gao Y. MiR-15a-5p negatively regulates cell survival and metastasis by targeting CXCL10 in chronic myeloid leukemia. Am J Transl Res 2017; 9:4308-4316. [PMID: 28979704 PMCID: PMC5622273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 03/22/2017] [Indexed: 06/07/2023]
Abstract
Chronic myeloid leukemia (CML) is a common malignant disease from hematopoietic system. Aberrant expression of microRNAs (miRNAs) has been found in CML, however, the roles of many miRNAs including miR-15a-5p in CML are still unknown. In this study, the expression and roles of miR-15a-5p in CML were investigated. We found that restoration miR-15a-5p expression in CML cells decreased cell growth, metastasis and enhanced cell apoptosis. Chemokine ligand 10 (CXCL10) was predicted as a target gene of miR-15a-5p, which was verified by luciferase assay. CXCL10 mRNA and protein was down-regulated in the CML cells with miR-15a-5p overexpression by real time RT-PCR and western blotting. We also found that there were low levels of miR-15a-5p companied with high levels of CXCL10 in blood samples from CML patients. In a conclusion, miR-15a-5p suppresses cell survival and metastasis of CML by targeting CXCL10, which is a therapeutic option for CML patients.
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Affiliation(s)
- Dan Chen
- Department of Hematology, Fourth Affiliated Hospital, School of Medicine, Zhejiang UniversityYiwu, China
| | - Dijiong Wu
- Department of Hematology, First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhou, China
| | - Keding Shao
- Department of Hematology, First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhou, China
| | - Baodong Ye
- Department of Hematology, First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhou, China
| | - Jian Huang
- Department of Hematology, Fourth Affiliated Hospital, School of Medicine, Zhejiang UniversityYiwu, China
| | - Yanting Gao
- Department of Hematology, First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhou, China
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4
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Perrotti D, Silvestri G, Stramucci L, Yu J, Trotta R. Cellular and Molecular Networks in Chronic Myeloid Leukemia: The Leukemic Stem, Progenitor and Stromal Cell Interplay. Curr Drug Targets 2017; 18:377-388. [PMID: 27307150 DOI: 10.2174/1389450117666160615074120] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 12/13/2022]
Abstract
The use of imatinib, second and third generation ABL tyrosine kinase inhibitors (TKI) (i.e. dasatinib, nilotinib, bosutinib and ponatinib) made CML a clinically manageable and, in a small percentage of cases, a cured disease. TKI therapy also turned CML blastic transformation into a rare event; however, disease progression still occurs in those patients who are refractory, not compliant with TKI therapy or develop resistance to multiple TKIs. In the past few years, it became clear that the BCRABL1 oncogene does not operate alone to drive disease emergence, maintenance and progression. Indeed, it seems that bone marrow (BM) microenvironment-generated signals and cell autonomous BCRABL1 kinase-independent genetic and epigenetic alterations all contribute to: i. persistence of a quiescent leukemic stem cell (LSC) reservoir, ii. innate or acquired resistance to TKIs, and iii. progression into the fatal blast crisis stage. Herein, we review the intricate leukemic network in which aberrant, but finely tuned, survival, mitogenic and self-renewal signals are generated by leukemic progenitors, stromal cells, immune cells and metabolic microenvironmental conditions (e.g. hypoxia) to promote LSC maintenance and blastic transformation.
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Affiliation(s)
- Danilo Perrotti
- Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, United States
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5
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Li Q, Wu Y, Zhang J, Yi T, Li W. MicroRNA-130a regulates cell malignancy by targeting RECK in chronic myeloid leukemia. Am J Transl Res 2016; 8:955-967. [PMID: 27158382 PMCID: PMC4846939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 01/26/2016] [Indexed: 06/05/2023]
Abstract
Emerging evidence has indicated that microRNAs are involved in tumor development and progression, acting as either tumor suppressors or oncogenes. In this study, we aimed to investigate the role of miR-130a in the pathogenesis of chronic myeloid leukemia (CML). Functional studies indicate that over-expression of miR-130a in A562 CML cells dramatically suppresses cell proliferation and induces cell apoptosis both in vitro and in vivo. Furthermore, we demonstrate that the transcriptional regulator RECK is a target of miR-130a. In conclusion, our study suggests that miR-130a may function as a novel tumor suppressor in CML, and its anti-oncogenic activity may involve the direct targeting and inhibition of RECK.
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Affiliation(s)
- Quan Li
- Department of Oncology, Xiangyang Central Hospital, Hubei University of Arts and ScienceXiangyang 441021, China
| | - Yaohui Wu
- Department of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology1277# Jiefang Avenue, Wuhan 430022, China
| | - Jian Zhang
- Department of Oncology, Xiangyang Central Hospital, Hubei University of Arts and ScienceXiangyang 441021, China
| | - Tienan Yi
- Department of Oncology, Xiangyang Central Hospital, Hubei University of Arts and ScienceXiangyang 441021, China
| | - Weiming Li
- Department of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology1277# Jiefang Avenue, Wuhan 430022, China
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6
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Zhu X, Zhao H, Lin Z, Zhang G. Functional studies of miR-130a on the inhibitory pathways of apoptosis in patients with chronic myeloid leukemia. Cancer Gene Ther 2015; 22:573-80. [PMID: 26494558 DOI: 10.1038/cgt.2015.50] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 08/27/2015] [Accepted: 09/03/2015] [Indexed: 02/05/2023]
Abstract
The p53 mutation in chronic myeloid leukemia (CML) led to decreased overall survival and therapy resistance which was also closely correlated with the downstream proto-oncogenes BCL-2, TCL-1 and MCL-1. We in this study aimed to investigate the function of miR130a in p53 tumor suppressor signaling pathway. We performed microRNA (miRNA) expression profile analysis in CML cancer stem cells of 38 cases and extracted total RNA from peripheral blood of 143 cases. Standard curves of U6 and miRNA were made from 10-fold serial dilutions of the cDNA, which were quantified using real-time quantitative PCR with SYBR Green by ABI 7300. The p53 mutations and BCR/ABL mutation status analysis in CML patients were detected by PCR and direct sequencing. Candidate targets of miR130a of putative relevance in CML pathogenesis were analyzed by bioinformatics approach. We then used dual-luciferase activity assay to verify the target genes of miR130a and used western blot analysis to elucidate the mechanism of miR130a on modulating drug resistance. The levels of miR-130a expression in CML were significantly lower in poor prognostic subgroups, defined by prognostic factors including mutated BCR/ABL status, p53 and ATM deletions and p53 mutations. Furthermore, underexpression of miR-130a was significantly associated with shorter overall survival and treatment-free survival in CML patients. We demonstrated that miR130a function as tumor suppressors by inhibiting multiple anti-apoptosis proteins, including BCL-2, MCL-1 and XIAP. This was a direct effect because miR130a negatively regulated expression of a BCL-2/MCL-1/XIAP 3'untranslated region-based reporter construct. Transfection of miR130a mimics into CML cells from 30 patients without p53 aberrations led to significant increases in apoptosis compared with transfection with the miRNA control. Besides, enforced expression of miR130a had no significant drug-sensitization effect in CML cells from p53-attenuated patients. MiR-130a may have an important role in the pathogenesis of CML and may be useful for assessing prognosis in patients with CML. Moreover, miR130a may provide a possible therapeutic avenue and a sensitive indicator of the activity of the p53 in CML.
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MESH Headings
- Apoptosis
- Ataxia Telangiectasia Mutated Proteins/genetics
- Female
- Fusion Proteins, bcr-abl
- Gene Expression
- Gene Expression Regulation, Leukemic
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/physiopathology
- Male
- MicroRNAs/genetics
- Middle Aged
- Mutation
- Prognosis
- Signal Transduction
- Tumor Suppressor Protein p53/genetics
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Affiliation(s)
- X Zhu
- Cancer Center, Beijing Shijitan Hospital, Capital Medical Hospital, Beijing, China
| | - H Zhao
- Clinical Department, Capital Medical University, Beijing, China
| | - Z Lin
- Clinical Research Center, Affiliated Hospital of Guangdong Medical College, Guangdong, China
| | - G Zhang
- The Breast Center, Cancer Hospital, Shantou University Medical College, Shantou, China
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7
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Senapedis WT, Baloglu E, Landesman Y. Clinical translation of nuclear export inhibitors in cancer. Semin Cancer Biol 2014; 27:74-86. [DOI: 10.1016/j.semcancer.2014.04.005] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 04/10/2014] [Indexed: 01/18/2023]
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8
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Walker CJ, Oaks JJ, Santhanam R, Neviani P, Harb JG, Ferenchak G, Ellis JJ, Landesman Y, Eisfeld AK, Gabrail NY, Smith CL, Caligiuri MA, Hokland P, Roy DC, Reid A, Milojkovic D, Goldman JM, Apperley J, Garzon R, Marcucci G, Shacham S, Kauffman MG, Perrotti D. Preclinical and clinical efficacy of XPO1/CRM1 inhibition by the karyopherin inhibitor KPT-330 in Ph+ leukemias. Blood 2013; 122:3034-44. [PMID: 23970380 PMCID: PMC3811176 DOI: 10.1182/blood-2013-04-495374] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 08/11/2013] [Indexed: 02/07/2023] Open
Abstract
As tyrosine kinase inhibitors (TKIs) fail to induce long-term response in blast crisis chronic myelogenous leukemia (CML-BC) and Philadelphia chromosome-positive (Ph(+)) acute lymphoblastic leukemia (ALL), novel therapies targeting leukemia-dysregulated pathways are necessary. Exportin-1 (XPO1), also known as chromosome maintenance protein 1, regulates cell growth and differentiation by controlling the nucleocytoplasmic trafficking of proteins and RNAs, some of which are aberrantly modulated in BCR-ABL1(+) leukemias. Using CD34(+) progenitors from CML, B-ALL, and healthy individuals, we found that XPO1 expression was markedly increased, mostly in a TKI-sensitive manner, in CML-BC and Ph(+) B-ALL. Notably, XPO1 was also elevated in Ph(-) B-ALL. Moreover, the clinically relevant XPO1 inhibitor KPT-330 strongly triggered apoptosis and impaired the clonogenic potential of leukemic, but not normal, CD34(+) progenitors, and increased survival of BCR-ABL1(+) mice, 50% of which remained alive and, mostly, became BCR-ABL1 negative. Moreover, KPT-330 compassionate use in a patient with TKI-resistant CML undergoing disease progression significantly reduced white blood cell count, blast cells, splenomegaly, lactate dehydrogenase levels, and bone pain. Mechanistically, KPT-330 altered the subcellular localization of leukemia-regulated factors including RNA-binding heterogeneous nuclear ribonucleoprotein A1 and the oncogene SET, thereby inducing reactivation of protein phosphatase 2A tumor suppressor and inhibition of BCR-ABL1 in CML-BC cells. Because XPO1 is important for leukemic cell survival, KPT-330 may represent an alternative therapy for TKI-refractory Ph(+) leukemias.
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MESH Headings
- Adult
- Animals
- Antigens, CD34/genetics
- Antigens, CD34/metabolism
- Antineoplastic Agents/pharmacology
- Apoptosis/drug effects
- Cell Proliferation/drug effects
- Clinical Trials, Phase I as Topic
- DNA-Binding Proteins
- Drug Evaluation, Preclinical
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/metabolism
- Gene Expression Regulation, Leukemic/drug effects
- Histone Chaperones/antagonists & inhibitors
- Histone Chaperones/genetics
- Histone Chaperones/metabolism
- Humans
- Hydrazines/pharmacology
- Karyopherins/antagonists & inhibitors
- Karyopherins/genetics
- Karyopherins/metabolism
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Male
- Mice
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/pathology
- Protein Kinase Inhibitors/pharmacology
- Protein Transport
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Ribonucleoproteins/antagonists & inhibitors
- Ribonucleoproteins/genetics
- Ribonucleoproteins/metabolism
- Transcription Factors/antagonists & inhibitors
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Triazoles/pharmacology
- Exportin 1 Protein
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Affiliation(s)
- Christopher J Walker
- Human Cancer Genetics Program, Department Molecular Virology Immunology and Medical Genetics
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9
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Turroni S, Tolomeo M, Mamone G, Picariello G, Giacomini E, Brigidi P, Roberti M, Grimaudo S, Pipitone RM, Di Cristina A, Recanatini M. A natural-like synthetic small molecule impairs bcr-abl signaling cascades and induces megakaryocyte differentiation in erythroleukemia cells. PLoS One 2013; 8:e57650. [PMID: 23460890 PMCID: PMC3584047 DOI: 10.1371/journal.pone.0057650] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 01/24/2013] [Indexed: 11/28/2022] Open
Abstract
Over the past years, we synthesized a series of new molecules that are hybrids of spirocyclic ketones as complexity-bearing cores with bi- and ter-phenyls as privileged fragments. Some of these newly-shaped small molecules showed antiproliferative, pro-apoptotic and differentiating activity in leukemia cell lines. In the present study, to investigate more in depth the mechanisms of action of these molecules, the protein expression profiles of K562 cells treated with or without the compounds IND_S1, MEL_T1, IND_S7 and MEL_S3 were analyzed using two-dimensional gel electrophoresis coupled with mass spectrometry. Proteome comparisons revealed several differentially expressed proteins, mainly related to cellular metabolism, chaperone activity, cytoskeletal organization and RNA biogenesis. The major results were validated by Western blot and qPCR. To attempt integrating findings into a cellular signaling context, proteomic data were explored using MetaCore. Network analysis highlighted relevant relationships between the identified proteins and additional potential effectors. Notably, qPCR validation of central hubs showed that the compound MEL_S3 induced high mRNA levels of the transcriptional factors EGR1 and HNF4-alpha; the latter to our knowledge is reported here for the first time to be present in K562 cells. Consistently with the known EGR1 involvement in the regulation of differentiation along megakaryocyte lineage, MEL_S3-treated leukemia cells showed a marked expression of glycoprotein IIb/IIIa (CD41) and glycoprotein Ib (CD42), two important cell markers in megakaryocytic differentiation, together with morphological aspects of megakaryoblasts and megakaryocytes.
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MESH Headings
- Biomarkers, Tumor/metabolism
- Cell Differentiation/drug effects
- Cell Differentiation/genetics
- Cell Shape/drug effects
- Cluster Analysis
- Fusion Proteins, bcr-abl/metabolism
- Gene Expression Regulation, Leukemic/drug effects
- Humans
- K562 Cells
- Leukemia, Erythroblastic, Acute/genetics
- Leukemia, Erythroblastic, Acute/pathology
- Megakaryocytes/drug effects
- Megakaryocytes/metabolism
- Megakaryocytes/pathology
- Multivariate Analysis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Proteome/metabolism
- Proteomics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Reproducibility of Results
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Small Molecule Libraries/chemistry
- Small Molecule Libraries/pharmacology
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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Affiliation(s)
- Silvia Turroni
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Manlio Tolomeo
- Interdepartmental Center of Research in Clinical Oncology and Department of Infectious Diseases, University of Palermo, Palermo, Italy
| | | | | | - Elisa Giacomini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Patrizia Brigidi
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Marinella Roberti
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
- * E-mail:
| | - Stefania Grimaudo
- Interdepartmental Center of Research in Clinical Oncology and Department of Infectious Diseases, University of Palermo, Palermo, Italy
| | - Rosaria Maria Pipitone
- Interdepartmental Center of Research in Clinical Oncology and Department of Infectious Diseases, University of Palermo, Palermo, Italy
| | - Antonietta Di Cristina
- Interdepartmental Center of Research in Clinical Oncology and Department of Infectious Diseases, University of Palermo, Palermo, Italy
| | - Maurizio Recanatini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
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10
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Liao B, Hu Y, Brewer G. RNA-binding protein insulin-like growth factor mRNA-binding protein 3 (IMP-3) promotes cell survival via insulin-like growth factor II signaling after ionizing radiation. J Biol Chem 2011; 286:31145-52. [PMID: 21757716 DOI: 10.1074/jbc.m111.263913] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ionizing radiation (IR) induces proapoptotic gene expression programs that inhibit cell survival. These programs often involve RNA-binding proteins that associate with their mRNA targets to elicit changes in mRNA stability and/or translation. The RNA-binding protein IMP-3 is an oncofetal protein overexpressed in many human malignancies. IMP-3 abundance correlates with tumor aggressiveness and poor prognosis. As such, IMP-3 is proving to be a highly significant biomarker in surgical pathology. Among its many mRNA targets, IMP-3 binds to and promotes translation of insulin-like growth factor II (IGFII) mRNA. Our earlier studies showed that reducing IMP-3 abundance with siRNAs reduced proliferation of human K562 chronic myeloid leukemia cells because of reduced IGF-II biosynthesis. However, the role of IMP-3 in apoptosis is unknown. Here, we have used IR-induced apoptosis of K562 cells as a model to explore a role for IMP-3 in cell survival. Knockdown of IMP-3 with siRNA increased susceptibility of cells to IR-induced apoptosis and led to reduced IGF-II production. Gene reporter assays revealed that IMP-3 acts through the 5' UTR of IGFII mRNA during apoptosis to promote translation. Finally, culture of IR-treated cells with recombinant IGF-II partially reversed the effects of IMP-3 knockdown on IR-induced apoptosis. Together, these results indicate that IMP-3 acts in part through the IGF-II pathway to promote cell survival in response to IR. Thus, IMP-3 might serve as a new drug target to increase sensitivity of CML cells or other cancers to IR therapy.
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Affiliation(s)
- Baisong Liao
- Department of Molecular Genetics, Microbiology, and Immunology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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