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Abroon S, Nouri M, Mahdavi M. Hesperidin/Salinomycin Combination; a Natural Product for Deactivation of the PI3K/Akt Signaling Pathway and Anti-Apoptotic Factors in KG1a Cells. J Fluoresc 2024:10.1007/s10895-024-03808-4. [PMID: 38916633 DOI: 10.1007/s10895-024-03808-4] [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: 03/27/2024] [Accepted: 06/06/2024] [Indexed: 06/26/2024]
Abstract
AML is a highly aggressive malignant clonal disease of hematopoietic origin. Hesperidin as a polyphenol glycoside, Activates the apoptotic pathway and salinomycin as a k + selective ionophore. We examined how hesperidin and salinomycin induce pro-apoptotic effects in KG1a cells. Cells were divided into four groups; 1) control cells (CRTL), 2) cells treated with hesperidin 85 μM, 3) cells treated with 2 μM salinomycin, 4) cells treated with combination of salinomycin and hesperidin. The MTT assay was implemented to determine the IC50 of hesperidin and salinomycin in KG1a cell lines. Propidium iodide staining and flow cytometry were used to analyze the distribution of the cell cycle. The level of ROS was evaluated by fluorescent microscopy and spectrophotometry. Additionally, Akt, XIAP, Bad, and FOXO1 gene expression was analyzed by real-time PCR. Hesperidin/Salinomycin decreased the viability of KG1a leukemic cells more than Hesperidin and Salinomycin separately. Changes in the shape of apoptotic cells and rise in ROS levels were detected after Hesperidin/Salinomycin treatment. Our findings showed that following Hesperidin/Salinomycin treatment, the expression of PI3K/AKT signaling pathway related genes (AKT, PTEN and FOXO1), were in line with the destruction of KG-1a cells. Furthermore, XIAP and BAD mRNA were regulated to trigger apoptosis in cancer cells. The study discovered that hesperidin and salinomycin, could effectively hinder the PI3K/Akt signaling pathway in leukemia cancer cells. Also, the combination of hesperidin and salinomycin has the potential to be a treatment option for acute myeloid leukemia.
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Affiliation(s)
- Sina Abroon
- Department of Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
- Department of biochemistry and clinical laboratories, Faculty of medicine, Tabriz University of medical sciences, Tabriz, Iran
| | - Mohammad Nouri
- Department of biochemistry and clinical laboratories, Faculty of medicine, Tabriz University of medical sciences, Tabriz, Iran
| | - Majid Mahdavi
- Department of Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran.
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
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2
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Liu J, Pan Y, Liu Y, Wei W, Hu X, Xin W, Chen N. The regulation of PTEN: Novel insights into functions as cancer biomarkers and therapeutic targets. J Cell Physiol 2023; 238:1693-1715. [PMID: 37334436 DOI: 10.1002/jcp.31053] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/10/2023] [Accepted: 05/17/2023] [Indexed: 06/20/2023]
Abstract
This review summarizes the implications of the primary tumor suppressor protein phosphatase and tensin homolog (PTEN) in aggressive cancer development. PTEN interacts with other cellular proteins or factors suggesting the existence of an intricate molecular network that regulates their oncogenic function. Accumulating evidence has shown that PTEN exists and plays a role in the cytoplasmic organelles and in the nucleus. PTEN blocks phosphoinositide 3-kinases (PI3K)-protein kinase B-mammalian target of rapamycin signaling pathway by dephosphorylating phosphatidylinositol (PI)-3,4,5-triphosphate to PI-4,5-bisphosphate thus counteracting PI3K function. Studies have shown that PTEN expression is tightly regulated at transcriptional, posttranscriptional, and posttranslational levels (including protein-protein interactions and posttranslational modifications). Despite recent advances in PTEN research, the regulation and function of the PTEN gene remain largely unknown. How mutation or loss of specific exons in the PTEN gene occurs and involves in cancer development is not clear. This review illustrates the regulatory mechanisms of PTEN expression and discusses how PTEN participates in tumor development and/or suppression. Future prospects for the clinical applications are also highlighted.
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Affiliation(s)
- Jie Liu
- Department of Dermatology, Skin Research, Peking University Shenzhen Hospital, Shenzhen, Guangdong, China
| | - Yongli Pan
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Yuheng Liu
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Wei Wei
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Xiaoping Hu
- Department of Dermatology, Skin Research, Peking University Shenzhen Hospital, Shenzhen, Guangdong, China
| | - Wenqiang Xin
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Nan Chen
- Department of Gastroenterology, Liaocheng People's Hospital, Liaocheng, China
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3
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Akizuki K, Sekine M, Kogure Y, Kameda T, Shide K, Koya J, Kamiunten A, Kubuki Y, Tahira Y, Hidaka T, Kiwaki T, Tanaka H, Sato Y, Kataoka H, Kataoka K, Shimoda K. TP53 and PTEN mutations were shared in concurrent germ cell tumor and acute megakaryoblastic leukemia. BMC Cancer 2020; 20:5. [PMID: 31898539 PMCID: PMC6941398 DOI: 10.1186/s12885-019-6497-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 12/23/2019] [Indexed: 01/08/2023] Open
Abstract
Background The occurrence of a mediastinal germ cell tumor (GCT) and hematological malignancy in the same patient is very rare. Due to its rarity, there have been only two reports of the concurrent cases undergoing detailed genetic analysis with whole-exome sequencing (WES), and the possible clonal relationship between the both tumors remained not fully elucidated. Methods We performed whole-exome sequencing analysis of mediastinal GCT and acute myeloid leukemia (AML) samples obtained from one young Japanese male adult patient with concurrent both tumors, and investigated the possible clonal relationship between them. Results Sixteen somatic mutations were detected in the mediastinal GCT sample and 18 somatic mutations in the AML sample. Mutations in nine genes, including TP53 and PTEN both known as tumor suppressor genes, were shared in both tumors. Conclusions All in our case and in the previous two cases with concurrent mediastinal GCT and AML undergoing with whole-exome sequencing analysis, TP53 and PTEN mutations were commonly shared in both tumors. These data not only suggest that these tumors share a common founding clone, but also indicate that associated mediastinal GCT and AML harboring TP53 and PTEN mutations represent a unique biological entity.
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Affiliation(s)
- Keiichi Akizuki
- Department of Gastroenterology and Hematology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Masaaki Sekine
- Department of Gastroenterology and Hematology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Yasunori Kogure
- Division of Molecular Oncology, National Cancer Center Research Institute, Tokyo, Japan
| | - Takuro Kameda
- Department of Gastroenterology and Hematology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Kotaro Shide
- Department of Gastroenterology and Hematology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Junji Koya
- Division of Molecular Oncology, National Cancer Center Research Institute, Tokyo, Japan
| | - Ayako Kamiunten
- Department of Gastroenterology and Hematology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Yoko Kubuki
- Department of Gastroenterology and Hematology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Yuki Tahira
- Department of Gastroenterology and Hematology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Tomonori Hidaka
- Department of Gastroenterology and Hematology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Takumi Kiwaki
- Department of Pathology, Faculty of Medicine, Section of Oncopathology and Regenerative Biology, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Hiroyuki Tanaka
- Department of Pathology, Faculty of Medicine, Section of Oncopathology and Regenerative Biology, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Yuichiro Sato
- Department of Diagnostic Pathology, Department of Pathology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Hiroaki Kataoka
- Department of Pathology, Faculty of Medicine, Section of Oncopathology and Regenerative Biology, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan
| | - Keisuke Kataoka
- Division of Molecular Oncology, National Cancer Center Research Institute, Tokyo, Japan
| | - Kazuya Shimoda
- Department of Gastroenterology and Hematology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki, 889-1692, Japan.
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Cardoso BA. The Bone Marrow Niche - The Tumor Microenvironment That Ensures Leukemia Progression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1219:259-293. [PMID: 32130704 DOI: 10.1007/978-3-030-34025-4_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The human body requires a constant delivery of fresh blood cells that are needed to maintain body homeostasis. Hematopoiesis is the process that drives the formation of new blood cells from a single stem cell. This is a complex, orchestrated and tightly regulated process that occurs within the bone marrow. When such process is faulty or deregulated, leukemia arises, develops and thrives by subverting normal hematopoiesis and availing the supplies of this rich milieu.In this book chapter we will describe and characterize the bone marrow microenvironment and its key importance for leukemia expansion. The several components of the bone marrow niche, their interaction with the leukemic cells and the cellular pathways activated within the malignant cells will be emphasized. Finally, novel therapeutic strategies to target this sibling interaction will also be discussed.
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Affiliation(s)
- Bruno António Cardoso
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal.
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5
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Luongo F, Colonna F, Calapà F, Vitale S, Fiori ME, De Maria R. PTEN Tumor-Suppressor: The Dam of Stemness in Cancer. Cancers (Basel) 2019; 11:E1076. [PMID: 31366089 PMCID: PMC6721423 DOI: 10.3390/cancers11081076] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 12/11/2022] Open
Abstract
PTEN is one of the most frequently inactivated tumor suppressor genes in cancer. Loss or variation in PTEN gene/protein levels is commonly observed in a broad spectrum of human cancers, while germline PTEN mutations cause inherited syndromes that lead to increased risk of tumors. PTEN restrains tumorigenesis through different mechanisms ranging from phosphatase-dependent and independent activities, subcellular localization and protein interaction, modulating a broad array of cellular functions including growth, proliferation, survival, DNA repair, and cell motility. The main target of PTEN phosphatase activity is one of the most significant cell growth and pro-survival signaling pathway in cancer: PI3K/AKT/mTOR. Several shreds of evidence shed light on the critical role of PTEN in normal and cancer stem cells (CSCs) homeostasis, with its loss fostering the CSC compartment in both solid and hematologic malignancies. CSCs are responsible for tumor propagation, metastatic spread, resistance to therapy, and relapse. Thus, understanding how alterations of PTEN levels affect CSC hallmarks could be crucial for the development of successful therapeutic approaches. Here, we discuss the most significant findings on PTEN-mediated control of CSC state. We aim to unravel the role of PTEN in the regulation of key mechanisms specific for CSCs, such as self-renewal, quiescence/cell cycle, Epithelial-to-Mesenchymal-Transition (EMT), with a particular focus on PTEN-based therapy resistance mechanisms and their exploitation for novel therapeutic approaches in cancer treatment.
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Affiliation(s)
- Francesca Luongo
- Istituto di Patologia Generale, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Francesca Colonna
- Istituto di Patologia Generale, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Federica Calapà
- Istituto di Patologia Generale, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Sara Vitale
- Istituto di Patologia Generale, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy
| | - Micol E Fiori
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, 00161 Rome, Italy.
| | - Ruggero De Maria
- Istituto di Patologia Generale, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy.
- Scientific Vice-Direction, Fondazione Policlinico Universitario "A. Gemelli"-I.R.C.C.S., Largo Francesco Vito 1-8, 00168 Rome, Italy.
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6
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Alasseiri M, Ahmed AU, Williams BRG. Mechanisms and consequences of constitutive activation of integrin-linked kinase in acute myeloid leukemia. Cytokine Growth Factor Rev 2018; 43:1-7. [PMID: 29903521 DOI: 10.1016/j.cytogfr.2018.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 05/31/2018] [Accepted: 06/05/2018] [Indexed: 12/22/2022]
Abstract
Integrin-linked kinase (ILK) has emerged as a critical adaptor and mediator protein in cell signaling pathways that is commonly deregulated in acute myeloid leukemia (AML). This has led to the expectation that therapeutic targeting of ILK may be a useful option in treating leukemia. Although ILK can regulate many cellular processes, including cell differentiation, survival, migration, apoptosis and production of pro-inflammatory cytokines, its role in promoting AML is still unclear. However, its ability to mediate phosphorylation and regulate the important hematopoietic stem cell regulators protein kinase B (AKT) and glycogen synthase kinase-3β supports ILK as an attractive target for the development of novel anticancer therapeutics. In this review, we summarize the existing knowledge of ILK signaling and its impact on cytokines, paying particular attention to the relevance of ILK signaling in AML. We also discuss the rationale for targeting ILK in the treatment of AML and conclude with perspectives on the future of ILK-targeted therapy in AML.
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Affiliation(s)
- Mohammed Alasseiri
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, VIC, 3168, Australia; Department of Clinical Laboratory Sciences, Faculty of Applied Medical Sciences, University of Tabuk, Tabuk, 71491, Saudi Arabia
| | - Afsar U Ahmed
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, VIC, 3168, Australia
| | - Bryan R G Williams
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, VIC, 3168, Australia; Department of Molecular and Translational Science, Monash University, Clayton, VIC, 3168, Australia.
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7
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Evaluation of the Gene Expression of the Cytoprotective Proteins in Response to Daunorubicin in U937 Cells. INTERNATIONAL JOURNAL OF CANCER MANAGEMENT 2018. [DOI: 10.5812/ijcm.10044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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8
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Ricciardi MR, Mirabilii S, Licchetta R, Piedimonte M, Tafuri A. Targeting the Akt, GSK-3, Bcl-2 axis in acute myeloid leukemia. Adv Biol Regul 2017; 65:36-58. [PMID: 28549531 DOI: 10.1016/j.jbior.2017.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 06/07/2023]
Abstract
Over the last few decades, there has been significant progress in the understanding of the pathogenetic mechanisms of the Acute Myeloid Leukemia (AML). However, despite important advances in elucidating molecular mechanisms, the treatment of AML has not improved significantly, remaining anchored at the standard chemotherapy regimen "3 + 7", with the prognosis of patients remaining severe, especially for the elderly and for those not eligible for transplant procedures. The biological and clinical heterogeneity of AML represents the major obstacle that hinders the improvement of prognosis and the identification of new effective therapeutic approaches. To date, abundant information has been collected on the genetic and molecular alterations of AML carrying prognostic significance. However, not enough is known on how AML progenitors regulate proliferation and survival by redundant and cross-talking signal transduction pathways (STP). Furthermore, it remains unclear how such complicated network affects prognosis and therapeutic treatment options, although many of these molecular determinants are potentially attractive for their druggable characteristics. In this review, some of the key STP frequently deregulated in AML, such as PI3k/Akt/mTOR pathway, GSK3 and components of Bcl-2 family of proteins, are summarized, highlighting in addition their interplay. Based on this information, we reviewed new targeted therapeutic approaches, focusing on the aberrant networks that sustain the AML blast proliferation, survival and drug resistance, aiming to improve disease treatment. Finally, we reported the approaches aimed at disrupting key signaling cross-talk overcoming resistances based on the combination of different targeting therapeutic strategies.
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Affiliation(s)
- Maria Rosaria Ricciardi
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy
| | - Simone Mirabilii
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy.
| | - Roberto Licchetta
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy
| | - Monica Piedimonte
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy
| | - Agostino Tafuri
- Hematology, "Sant'Andrea" Hospital-Sapienza, University of Rome, Department of Clinical and Molecular Medicine, Rome, Italy
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9
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Pulliam SR, Pellom ST, Shanker A, Adunyah SE. Butyrate regulates the expression of inflammatory and chemotactic cytokines in human acute leukemic cells during apoptosis. Cytokine 2016; 84:74-87. [PMID: 27253488 DOI: 10.1016/j.cyto.2016.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 05/12/2016] [Accepted: 05/13/2016] [Indexed: 02/06/2023]
Abstract
Butyrate is a histone deacetylase inhibitor implicated in many studies as a potential therapy for various forms of cancer. High concentrations of butyrate (>1.5mM) have been shown to activate apoptosis in several cancer cell lines including prostate, breast, and leukemia. Butyrate is also known to influence multiple signaling pathways that are mediators of cytokine production. The purpose of this study was to evaluate the impact of high concentrations of butyrate on the cancer microenvironment vis-à-vis apoptosis, cellular migration, and capacity to modulate cytokine expression in cancer cells. The results indicate that high concentrations of butyrate induced a 2-fold activation of caspase-3 and reduced cell viability by 60% in U937 leukemia cells. Within 24h, butyrate significantly decreased the levels of chemokines CCL2 and CCL5 in HL-60 and U937 cells, and decreased CCL5 in THP-1 leukemia cells. Differential effects were observed in treatments with valproic acid for CCL2 and CCL5 indicating butyrate-specificity. Many of the biological effects examined in this study are linked to activation of the AKT and MAPK signaling pathways; therefore, we investigated whether butyrate alters the levels of phosphorylated forms of these signaling proteins and how it correlated with the expression of chemokines. The results show that butyrate may partially regulate CCL5 production via p38 MAPK. The decrease in p-ERK1/2 and p-AKT levels correlated with the decrease in CCL2 production. These data suggest that while promoting apoptosis, butyrate has the potential to influence the cancer microenvironment by inducing differential expression of cytokines.
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Affiliation(s)
- Stephanie R Pulliam
- School of Graduate Studies and Research, Meharry Medical College, 1005 Dr. DB Todd, Jr. Blvd., Nashville, TN 37208, USA; Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, 1005 Dr. DB Todd, Jr. Blvd., Nashville, TN 37208, USA
| | - Samuel T Pellom
- School of Graduate Studies and Research, Meharry Medical College, 1005 Dr. DB Todd, Jr. Blvd., Nashville, TN 37208, USA; Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, 1005 Dr. DB Todd, Jr. Blvd., Nashville, TN 37208, USA; Department of Microbiology and Immunology, School of Medicine, Meharry Medical College, 1005 Dr. DB Todd, Jr. Blvd., Nashville, TN 37208, USA
| | - Anil Shanker
- School of Graduate Studies and Research, Meharry Medical College, 1005 Dr. DB Todd, Jr. Blvd., Nashville, TN 37208, USA; Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, 1005 Dr. DB Todd, Jr. Blvd., Nashville, TN 37208, USA; Host-Tumor Interactions Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Samuel E Adunyah
- School of Graduate Studies and Research, Meharry Medical College, 1005 Dr. DB Todd, Jr. Blvd., Nashville, TN 37208, USA; Department of Biochemistry and Cancer Biology, School of Medicine, Meharry Medical College, 1005 Dr. DB Todd, Jr. Blvd., Nashville, TN 37208, USA.
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Morotti A, Panuzzo C, Crivellaro S, Carrà G, Torti D, Guerrasio A, Saglio G. The Role of PTEN in Myeloid Malignancies. Hematol Rep 2015; 7:5844. [PMID: 26734127 PMCID: PMC4691678 DOI: 10.4081/hr.2015.6027] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 10/20/2015] [Indexed: 12/31/2022] Open
Abstract
PTEN deletion in the mouse and in the zebrafish highlights the essential role of this tumor suppressor in the development of myeloid malignancies, in particular acute myeloid leukemia and myeloproliferative disorders. In humans, extensive genetic sequences of myeloid malignancies did not reveal recurrent PTEN mutations and deletions. However, PTEN was shown to be functionally inactivated in several acute myeloid leukemia and chronic myeloid leukemia samples, through both post-trasductional modifications, changes in protein levels and cellular compartmentalization. Notably, non genomic inactivation of PTEN in myeloid malignancies could represent a challenging therapeutic opportunity for these diseases. Targeting those mechanisms that affect PTEN function could indeed promote PTEN reactivation with consequent cancer selective apoptosis induction. In this review we will describe the role of PTEN in the development of myeloid malignancies.
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Affiliation(s)
- Alessandro Morotti
- Department of Clinical and Biological Sciences, University of Turin , Orbassano, Italy
| | - Cristina Panuzzo
- Department of Clinical and Biological Sciences, University of Turin , Orbassano, Italy
| | - Sabrina Crivellaro
- Department of Clinical and Biological Sciences, University of Turin , Orbassano, Italy
| | - Giovanna Carrà
- Department of Clinical and Biological Sciences, University of Turin , Orbassano, Italy
| | - Davide Torti
- Department of Clinical and Biological Sciences, University of Turin , Orbassano, Italy
| | - Angelo Guerrasio
- Department of Clinical and Biological Sciences, University of Turin , Orbassano, Italy
| | - Giuseppe Saglio
- Department of Clinical and Biological Sciences, University of Turin , Orbassano, Italy
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Lima K, Ribeiro DM, Campos PDM, Costa FF, Traina F, Saad STO, Sonati MDF, Machado-Neto JA. Differential profile of PIP4K2A expression in hematological malignancies. Blood Cells Mol Dis 2015; 55:228-35. [PMID: 26227852 DOI: 10.1016/j.bcmd.2015.06.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 06/21/2015] [Indexed: 10/23/2022]
Abstract
PIP4K2A is a lipid kinase that phosphorylates PtdIns5P, generating PtdIns4,5P2. Recently, PIP4K2A was identified as a potential target in acute myeloid leukemia cells. The objective of the present study was to investigate the PIP4K2A expression in hematological malignancies and verify the effects of PIP4K2A silencing on proliferation and survival of leukemia cell lines. PIP4K2A was found to be a cytoplasmic and nuclear protein with reduced levels in leukemia cell lines compared to normal leukocytes. PIP4K2A mRNA levels were significantly reduced in bone marrow cells from acute lymphoid leukemia (ALL) patients compared with healthy donors and in myelodysplastic syndromes (MDS) with ≥5% compared with <5% bone marrow blasts. Low PIP4K2A expression (lowest tertile versus 2 higher tertiles) negatively impacted overall survival of MDS patients by univariate analysis. PIP4K2A silencing did not modulate cell proliferation, clonogenicity and apoptosis of HEL and Namalwa leukemia cells. In summary, we characterized the expression of PIP4K2A in a cohort of patients with hematological malignancies and we found that PIP4K2A mRNA expression is downregulated in RAEB-1/RAEB-2 MDS and ALL cells, and PIP4K2A silencing does not modulate cell survival in HEL and Namalwa leukemia cells.
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Affiliation(s)
- Keli Lima
- Department of Clinical Pathology, School of Medical Sciences, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil
| | - Daniela Maria Ribeiro
- Department of Clinical Pathology, School of Medical Sciences, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil
| | - Paula de Melo Campos
- Hematology and Hemotherapy Center, University of Campinas - UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil
| | - Fernando Ferreira Costa
- Hematology and Hemotherapy Center, University of Campinas - UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil
| | - Fabiola Traina
- Hematology and Hemotherapy Center, University of Campinas - UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil
| | - Sara Teresinha Olalla Saad
- Hematology and Hemotherapy Center, University of Campinas - UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil
| | - Maria de Fátima Sonati
- Department of Clinical Pathology, School of Medical Sciences, University of Campinas - UNICAMP, Campinas, São Paulo, Brazil
| | - João Agostinho Machado-Neto
- Hematology and Hemotherapy Center, University of Campinas - UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, São Paulo, Brazil.
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12
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de Necochea-Campion R, Diaz Osterman CJ, Hsu HW, Fan J, Mirshahidi S, Wall NR, Chen CS. AML sensitivity to YM155 is modulated through AKT and Mcl-1. Cancer Lett 2015; 366:44-51. [PMID: 26118775 DOI: 10.1016/j.canlet.2015.05.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 05/29/2015] [Accepted: 05/29/2015] [Indexed: 10/23/2022]
Abstract
HL60 and U937 (acute myeloid leukemia (AML) cell lines) were assessed for sensitivity to YM155, and found to have distinct sensitive and resistant phenotypes, respectively. In HL60 cells, YM155 inhibition of growth proliferation was due to apoptosis which was measured by annexin V/PI staining. YM155 induced apoptosis through activation of intrinsic and extrinsic pathways that also culminated in caspase-3 activity and PARP cleavage. YM155 sensitivity was partially associated with this compound's ability to down-regulate survivin transcription since this was more pronounced in the HL60 cell line. However, marked differences were also observed in XIAP, Bcl-2, and Mcl-1L, and Mcl-1s. Furthermore, YM155 treatment completely inhibited production of total Akt protein in HL60, but not U937 cells. Importantly, Akt activity (pAkt-Ser473) levels were maintained in YM155 treated U937 cells which may help stabilize other anti-apoptotic proteins. Combination treatments with an Akt inhibitor, MK-2206, reduced levels of pAkt-Ser473 in U937 cells and synergistically sensitized them to YM155 cytotoxicity. Collectively our results indicate that Akt signaling may be an important factor mediating YM155 response in AML, and combinatorial therapies with Akt inhibitors could improve treatment efficacy in YM155-resistant cells.
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Affiliation(s)
- Rosalia de Necochea-Campion
- Department of Internal Medicine, Division of Hematology and Medical Oncology & Biospecimen Laboratory, Loma Linda University, Loma Linda, CA 92350, USA
| | - Carlos J Diaz Osterman
- Center for Health Disparities & Molecular Medicine, Department of Basic Sciences, Division of Biochemistry, Loma Linda University, Loma Linda, CA 92350, USA
| | - Heng-Wei Hsu
- Department of Internal Medicine, Division of Hematology and Medical Oncology & Biospecimen Laboratory, Loma Linda University, Loma Linda, CA 92350, USA
| | - Junjie Fan
- Department of Internal Medicine, Division of Hematology and Medical Oncology & Biospecimen Laboratory, Loma Linda University, Loma Linda, CA 92350, USA
| | - Saied Mirshahidi
- Department of Internal Medicine, Division of Hematology and Medical Oncology & Biospecimen Laboratory, Loma Linda University, Loma Linda, CA 92350, USA
| | - Nathan R Wall
- Center for Health Disparities & Molecular Medicine, Department of Basic Sciences, Division of Biochemistry, Loma Linda University, Loma Linda, CA 92350, USA.
| | - Chien-Shing Chen
- Department of Internal Medicine, Division of Hematology and Medical Oncology & Biospecimen Laboratory, Loma Linda University, Loma Linda, CA 92350, USA.
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Inositol polyphosphate 4-phosphatase II (INPP4B) is associated with chemoresistance and poor outcome in AML. Blood 2015; 125:2815-24. [DOI: 10.1182/blood-2014-09-603555] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 02/19/2015] [Indexed: 01/06/2023] Open
Abstract
Key Points
INPP4B promotes chemoresistance in AML independent of phosphoinositide phosphatase function.
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14
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Fransecky L, Mochmann LH, Baldus CD. Outlook on PI3K/AKT/mTOR inhibition in acute leukemia. MOLECULAR AND CELLULAR THERAPIES 2015; 3:2. [PMID: 26056603 PMCID: PMC4452048 DOI: 10.1186/s40591-015-0040-8] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 03/05/2015] [Indexed: 02/08/2023]
Abstract
Technological advances allowing high throughput analyses across numerous cancer tissues have allowed much progress in understanding complex cellular signaling. In the future, the genetic landscape in cancer may have more clinical relevance than diagnosis based on tumor origin. This progress has emphasized PI3K/AKT/mTOR, among others, as a central signaling center of cancer development due to its governing control in cellular growth, survival, and metabolism. The discovery of high frequencies of mutations in the PI3K/AKT/mTOR pathway in different cancer entities has sparked interest to inhibit elements of this pathway. In acute leukemia pharmacological interruption has yet to achieve desirable efficacy as targetable downstream mutations in PI3K/AKT/mTOR are absent. Nevertheless, mutations in membrane-associated genes upstream of PI3K/AKT/mTOR are frequent in acute leukemia and are associated with aberrant activation of PI3K/AKT/mTOR thus providing a good rationale for further exploration. This review attempts to summarize key findings leading to aberrant activation and to reflect on both promises and challenges of targeting PI3K/AKT/mTOR in acute leukemia. Our emphasis lies on the insights gained through high-throughput data acquisition that open up new avenues for identifying specific subgroups of acute leukemia as ideal candidates for PI3K/AKT/mTOR targeted therapy.
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Affiliation(s)
- Lars Fransecky
- Department of Hematology and Oncology, Charité University Hospital Berlin, Campus Benjamin Franklin, Berlin, Germany
| | - Liliana H Mochmann
- Department of Hematology and Oncology, Charité University Hospital Berlin, Campus Benjamin Franklin, Berlin, Germany
| | - Claudia D Baldus
- Department of Hematology and Oncology, Charité University Hospital Berlin, Campus Benjamin Franklin, Berlin, Germany
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15
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Milella M, Falcone I, Conciatori F, Cesta Incani U, Del Curatolo A, Inzerilli N, Nuzzo CMA, Vaccaro V, Vari S, Cognetti F, Ciuffreda L. PTEN: Multiple Functions in Human Malignant Tumors. Front Oncol 2015; 5:24. [PMID: 25763354 PMCID: PMC4329810 DOI: 10.3389/fonc.2015.00024] [Citation(s) in RCA: 323] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/22/2015] [Indexed: 12/16/2022] Open
Abstract
PTEN is the most important negative regulator of the PI3K signaling pathway. In addition to its canonical, PI3K inhibition-dependent functions, PTEN can also function as a tumor suppressor in a PI3K-independent manner. Indeed, the PTEN network regulates a broad spectrum of biological functions, modulating the flow of information from membrane-bound growth factor receptors to nuclear transcription factors, occurring in concert with other tumor suppressors and oncogenic signaling pathways. PTEN acts through its lipid and protein phosphatase activity and other non-enzymatic mechanisms. Studies conducted over the past 10 years have expanded our understanding of the biological role of PTEN, showing that in addition to its ability to regulate proliferation and cell survival, it also plays an intriguing role in regulating genomic stability, cell migration, stem cell self-renewal, and tumor microenvironment. Changes in PTEN protein levels, location, and enzymatic activity through various molecular mechanisms can generate a continuum of functional PTEN levels in inherited syndromes, sporadic cancers, and other diseases. PTEN activity can indeed, be modulated by mutations, epigenetic silencing, transcriptional repression, aberrant protein localization, and post-translational modifications. This review will discuss our current understanding of the biological role of PTEN, how PTEN expression and activity are regulated, and the consequences of PTEN dysregulation in human malignant tumors.
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Affiliation(s)
- Michele Milella
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Italia Falcone
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Fabiana Conciatori
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Ursula Cesta Incani
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Anais Del Curatolo
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Nicola Inzerilli
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Carmen M A Nuzzo
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Vanja Vaccaro
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Sabrina Vari
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Francesco Cognetti
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
| | - Ludovica Ciuffreda
- Division of Medical Oncology A, Regina Elena National Cancer Institute , Rome , Italy
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16
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Oshrine BR, Olsen MN, Heneghan M, Wertheim G, Daber R, Wilmoth DM, Biegel JA, Pawel B, Aplenc R, King RL. Acquired isochromosome 12p, somatic TP53 and PTEN mutations, and a germline ATM variant in an adolescent male with concurrent acute megakaryoblastic leukemia and mediastinal germ cell tumor. Cancer Genet 2014; 207:153-9. [PMID: 24831771 DOI: 10.1016/j.cancergen.2014.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/24/2014] [Accepted: 03/27/2014] [Indexed: 01/21/2023]
Abstract
Previous reports have described an association between hematologic malignancies (HMs) and extragonadal germ cell tumor (GCT). Most patients have been adolescent males with mediastinal nonseminomatous GCT. Although a variety of HMs have been reported, there is a striking predilection toward acute megakaryoblastic leukemia (AMKL). Shared cytogenetic anomalies--particularly isochromosome 12p [i(12p)]--have suggested common clonal origins to the tumors. We report the case of a 17-year-old boy presenting with AMKL and a synchronous mediastinal GCT, with the characteristic i(12p) in both neoplasms. The common clonal origin of the AMKL and GCT was further confirmed with massively parallel sequencing, which identified somatic TP53 and PTEN mutations, as well as a rare germline ATM variant. Although these represent commonly mutated genes in cancer, this combination of mutations is not typically associated with either GCT or AMKL, suggesting that these tumors may represent unique biologic entities when they co-occur.
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Affiliation(s)
- Benjamin R Oshrine
- Division of Oncology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.
| | - Molly N Olsen
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mallorie Heneghan
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Gerald Wertheim
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Robert Daber
- Department of Pathology and Lab Medicine, Center for Personalized Diagnostics, University of Pennsylvania, Philadelphia, PA, USA
| | - Donna M Wilmoth
- Department of Pathology and Lab Medicine, Center for Personalized Diagnostics, University of Pennsylvania, Philadelphia, PA, USA
| | - Jaclyn A Biegel
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA; Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Bruce Pawel
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Richard Aplenc
- Division of Oncology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Rebecca L King
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, USA
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17
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Song SJ, Ito K, Ala U, Kats L, Webster K, Sun SM, Jongen-Lavrencic M, Manova-Todorova K, Teruya-Feldstein J, Avigan DE, Delwel R, Pandolfi PP. The oncogenic microRNA miR-22 targets the TET2 tumor suppressor to promote hematopoietic stem cell self-renewal and transformation. Cell Stem Cell 2014; 13:87-101. [PMID: 23827711 DOI: 10.1016/j.stem.2013.06.003] [Citation(s) in RCA: 255] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 03/07/2013] [Accepted: 06/11/2013] [Indexed: 12/21/2022]
Abstract
MicroRNAs are frequently deregulated in cancer. Here we show that miR-22 is upregulated in myelodysplastic syndrome (MDS) and leukemia and its aberrant expression correlates with poor survival. To explore its role in hematopoietic stem cell function and malignancy, we generated transgenic mice conditionally expressing miR-22 in the hematopoietic compartment. These mice displayed reduced levels of global 5-hydroxymethylcytosine (5-hmC) and increased hematopoietic stem cell self-renewal accompanied by defective differentiation. Conversely, miR-22 inhibition blocked proliferation in both mouse and human leukemic cells. Over time, miR-22 transgenic mice developed MDS and hematological malignancies. We also identify TET2 as a key target of miR-22 in this context. Ectopic expression of TET2 suppressed the miR-22-induced phenotypes. Downregulation of TET2 protein also correlated with poor clinical outcomes and miR-22 overexpression in MDS patients. Our results therefore identify miR-22 as a potent proto-oncogene and suggest that aberrations in the miR-22/TET2 regulatory network are common in hematopoietic malignancies.
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Affiliation(s)
- Su Jung Song
- Cancer Genetics Program, Beth Israel Deaconess Cancer Center, Harvard Medical School, Boston, MA 02215, USA
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18
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Abstract
PTEN (phosphatase and tensin homolog deleted in chromosome 10) is a bona fide dual lipid and protein phosphatase with cytoplasmic (Cy) and nuclear localization. PTEN nuclear exclusion has been associated with tumorigenesis. Nucleophosmin (NPM1) is frequently mutated in acute myeloid leukemia (AML) and displays Cy localization in mutated nucleophosmin (NPMc+) AML. Here we show that NPM1 directly interacts with herpes virus-associated ubiquitin specific protease (HAUSP), which is known as a PTEN deubiquitinating enzyme. Strikingly, PTEN is aberrantly localized in AML carrying NPMc+. Mechanistically, NPM1 in the nucleus opposes HAUSP-mediated deubiquitination and this promotes the shuttle of PTEN to the cytoplasm. In the cytoplasm, NPMc+ prevents HAUSP from deubiquitinating PTEN, causing the latter to stay in the cytoplasm where it is polyubiquitinated and degraded. Our findings delineate a new NPM1-HAUSP molecular interaction controlling PTEN deubiquitination and trafficking.
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19
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Gao N, Cheng S, Budhraja A, Gao Z, Chen J, Liu EH, Huang C, Chen D, Yang Z, Liu Q, Li P, Shi X, Zhang Z. Ursolic acid induces apoptosis in human leukaemia cells and exhibits anti-leukaemic activity in nude mice through the PKB pathway. Br J Pharmacol 2012; 165:1813-1826. [PMID: 21950524 PMCID: PMC3372832 DOI: 10.1111/j.1476-5381.2011.01684.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 08/11/2011] [Accepted: 08/16/2011] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND AND PURPOSE Ursolic acid (UA) has been extensively used as an anti-leukaemic agent in traditional Chinese medicine. In the present study, we investigated the ability of UA to induce apoptosis in human leukaemia cells in relation to its effects on caspase activation, Mcl-1 down-regulation and perturbations in stress-induced signalling pathways such as PKB and JNK. EXPERIMENTAL APPROACH Leukaemia cells were treated with UA after which apoptosis, caspase activation, PKB and JNK signalling pathways were evaluated. The anti-tumour activity of UA was evaluated using xenograft mouse model. KEY RESULTS UA induced apoptosis in human leukaemia cells in a dose- and time-dependent manner; this was associated with caspase activation, down-regulation of Mcl-1 and inactivation of PKB accompanied by activation of JNK. Enforced activation of PKB by a constitutively active PKB construct prevented UA-mediated JNK activation, Mcl-1 down-regulation, caspase activation and apoptosis. Conversely, UA lethality was potentiated by the PI3-kinase inhibitor LY294002. Interruption of the JNK pathway by pharmacological or genetic (e.g. siRNA) attenuated UA-induced apoptosis. Furthermore, UA-mediated inhibition of tumour growth in vivo was associated with induction of apoptosis, inactivation of PKB as well as activation of JNK. CONCLUSIONS AND IMPLICATIONS Collectively, these findings suggest a hierarchical model of UA-induced apoptosis in human leukaemia cells in which UA induces PKB inactivation, leading to JNK activation and culminating in Mcl-1 down-regulation, caspase activation and apoptosis. These findings indicate that interruption of PKB/JNK pathways may represent a novel therapeutic strategy in haematological malignancies.
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Affiliation(s)
- Ning Gao
- Department of Pharmacognosy, College of Pharmacy, 3rd Military Medical UniversityChongqing, China
- Graduate Center for Toxicology, College of Medicine, University of KentuckyLexington, Kentucky
| | - Senping Cheng
- Graduate Center for Toxicology, College of Medicine, University of KentuckyLexington, Kentucky
| | - Amit Budhraja
- Graduate Center for Toxicology, College of Medicine, University of KentuckyLexington, Kentucky
| | - Ziyi Gao
- Graduate Center for Toxicology, College of Medicine, University of KentuckyLexington, Kentucky
| | - Jieping Chen
- Department of Hematology, Southwest Hospital, 3rd Military Medical UniversityChongqing, China
| | - E-Hu Liu
- Department of Pharmacognosy, College of Pharmacy, 3rd Military Medical UniversityChongqing, China
| | - Cheng Huang
- Graduate Center for Toxicology, College of Medicine, University of KentuckyLexington, Kentucky
| | - Deying Chen
- Department of Pharmacognosy, College of Pharmacy, 3rd Military Medical UniversityChongqing, China
| | - Zailin Yang
- Department of Hematology, Southwest Hospital, 3rd Military Medical UniversityChongqing, China
| | - Qun Liu
- Key Laboratory of Modern Chinese Medicines (China Pharmaceutical University), Ministry of EducationNanjing, China
| | - Ping Li
- Key Laboratory of Modern Chinese Medicines (China Pharmaceutical University), Ministry of EducationNanjing, China
| | - Xianglin Shi
- Graduate Center for Toxicology, College of Medicine, University of KentuckyLexington, Kentucky
| | - Zhuo Zhang
- Graduate Center for Toxicology, College of Medicine, University of KentuckyLexington, Kentucky
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3,3'-Diindolylmethane exhibits antileukemic activity in vitro and in vivo through a Akt-dependent process. PLoS One 2012; 7:e31783. [PMID: 22363731 PMCID: PMC3283648 DOI: 10.1371/journal.pone.0031783] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 01/16/2012] [Indexed: 12/15/2022] Open
Abstract
3,3′-diindolylmethane (DIM), one of the active products derived from Brassica plants, is a promising antitumor agent. The present study indicated that DIM significantly induced apoptosis in U937 human leukemia cells in dose- and time-dependent manners. These events were also noted in other human leukemia cells (Jurkat and HL-60) and primary human leukemia cells (AML) but not in normal bone marrow mononuclear cells. We also found that DIM-induced lethality is associated with caspases activation, myeloid cell leukemia-1 (Mcl-1) down-regulation, p21cip1/waf1 up-regulation, and Akt inactivation accompanied by c-jun NH2-terminal kinase (JNK) activation. Enforced activation of Akt by a constitutively active Akt construct prevented DIM-mediated caspase activation, Mcl-1 down-regulation, JNK activation, and apoptosis. Conversely, DIM lethality was potentiated by the PI3K inhibitor LY294002. Interruption of the JNK pathway by pharmacologic or genetic approaches attenuated DIM-induced caspases activation, Mcl-1 down-regulation, and apoptosis. Lastly, DIM inhibits tumor growth of mouse U937 xenograft, which was related to induction of apoptosis and inactivation of Akt, as well as activation of JNK. Collectively, these findings suggest that DIM induces apoptosis in human leukemia cell lines and primary human leukemia cells, and exhibits antileukemic activity in vivo through Akt inactivation and JNK activation.
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Yoshimi A, Kurokawa M. Evi1 forms a bridge between the epigenetic machinery and signaling pathways. Oncotarget 2012; 2:575-86. [PMID: 21795762 PMCID: PMC3248179 DOI: 10.18632/oncotarget.304] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Recent studies have demonstrated the significance of the leukemia oncogene Evi1 as the regulator of hematopoietic stem cells and marker of poor clinical outcomes in myeloid malignancies. Evi1-mediated leukemogenic activities include a wide array of functions such as the induction of epigenetic modifications, transcriptional control, and regulation of signaling pathways. We have recently succeeded in comprehensively elucidating the oncogenic function of Evi1 in a model of the polycomb-Evi1-PTEN/AKT/mTOR axis. These results may provide us with novel therapeutic approaches to conquer the poor prognosis associated with Evi1-activated leukemia or other solid tumors with high Evi1 expression. Here, we review the current understanding of the role of Evi1 in controlling the development of leukemia and highlight potential modalities for targeting factors involved in Evi1-regulated signaling.
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Affiliation(s)
- Akihide Yoshimi
- Department of Hematology and Oncology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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22
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Cheng Z, Yang N, Liang W, Yan X, Li L, Pan L. Effect of phosphatase and tensin homology deleted on chromosome 10 (PTEN) gene transfection on reversal of multidrug resistance in K562/ADM cells. Leuk Lymphoma 2012; 53:1383-9. [DOI: 10.3109/10428194.2011.650695] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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23
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The PI3K/PKB signaling module as key regulator of hematopoiesis: implications for therapeutic strategies in leukemia. Blood 2012; 119:911-23. [PMID: 22065598 DOI: 10.1182/blood-2011-07-366203] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Abstract
An important mediator of cytokine signaling implicated in regulation of hematopoiesis is the PI3K/protein kinase B (PKB/c-Akt) signaling module. Constitutive activation of this signaling module has been observed in a large group of leukemias. Because activation of this signaling pathway has been demonstrated to be sufficient to induce hematologic malignancies and is thought to correlate with poor prognosis and enhanced drug resistance, it is considered to be a promising target for therapy. A high number of pharmacologic inhibitors directed against either individual or multiple components of this pathway have already been developed to improve therapy. In this review, the safety and efficacy of both single and dual-specificity inhibitors will be discussed as well as the potential of combination therapy with either inhibitors directed against other signal transduction molecules or classic chemotherapy.
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Class I phosphoinositide 3-kinases in normal and pathologic hematopoietic cells. Curr Top Microbiol Immunol 2012; 362:163-84. [PMID: 23086418 DOI: 10.1007/978-94-007-5025-8_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Class I phosphoinositide 3-kinases which produce the D3-phosphoinositide second messenger phosphatidylinositol 3,4,5-trisphosphate in response to membrane receptors activation play a critical role in cell proliferation, survival, metabolism, and motility. These lipid kinases and the phosphatases regulating the level of D3-phosphoinositides have been an intense area of research these last two decades. The class I phosphoinositide 3-kinases signaling is found aberrantly activated in numerous human cancers, including in malignant hemopathies, and are important therapeutic targets for cancer therapy. Haematopoiesis is an ongoing process which generates the distinct blood cell types from a common hematopoietic stem cell through the action of a variety of cytokines. In the human adult hematopoiesis occurs primarily in the bone marrow, and defects in hematopoiesis result in diseases, such as anemia, thrombocytopenia, myeloproliferative syndromes, or leukemia. Here we give a brief overview of the role of class I phosphoinositide 3-kinases in hematopoietic stem cells, in hematopoietic lineage development and in leukemia, particularly in acute myeloid leukemia and summarize the potential therapeutic implications.
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25
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Budhraja A, Gao N, Zhang Z, Son YO, Cheng S, Wang X, Ding S, Hitron A, Chen G, Luo J, Shi X. Apigenin induces apoptosis in human leukemia cells and exhibits anti-leukemic activity in vivo. Mol Cancer Ther 2011; 11:132-42. [PMID: 22084167 DOI: 10.1158/1535-7163.mct-11-0343] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this study, we investigated the functional role of Akt and c-jun-NH(2)-kinase (JNK) signaling cascades in apigenin-induced apoptosis in U937 human leukemia cells and anti-leukemic activity of apigenin in vivo. Apigenin induced apoptosis by inactivation of Akt with a concomitant activation of JNK, Mcl-1 and Bcl-2 downregulation, cytochrome c release from mitochondria, and activation of caspases. Constitutively active myristolated Akt prevented apigenin-induced JNK, caspase activation, and apoptosis. Conversely, LY294002 and a dominant-negative construct of Akt potentiated apigenin-induced apoptosis in leukemia cells. Interruption of the JNK pathway showed marked reduction in apigenin-induced caspase activation and apoptosis in leukemia cells. Furthermore, in vivo administration of apigenin resulted in attenuation of tumor growth in U937 xenografts accompanied by inactivation of Akt and activation of JNK. Attenuation of tumor growth in U937 xenografts by apigenin raises the possibility that apigenin may have clinical implications and can be further tested for incorporating in leukemia treatment regimens.
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Affiliation(s)
- Amit Budhraja
- Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536, USA
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Clinical implications of novel mutations in epigenetic modifiers in AML. Hematol Oncol Clin North Am 2011; 25:1119-33. [PMID: 22093580 DOI: 10.1016/j.hoc.2011.09.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The studies highlighted in this article suggest that mutations in TET2 mutations may impart adverse outcome in patients with CN-AML, whereas mutations in DNMT3a may have adverse implications in a broader set of patients with AML. The data with IDH enzyme mutations are less clear, in that individual IDH1 and IDH2 mutations may have different clinical effects and the data so far have not suggested a uniform effect on outcome. Despite the exciting data indicating that mutational testing for these alterations may be clinically useful, several challenges to understanding their clinical relevance remain. First, patients may simultaneously have mutations in multiple genes described in this article (FLT3, NPM1, CEBPa, DNMT3a, IDH1/2, or TET2), and in additional genes not mentioned earlier (Ras,47 PTEN,48 PHF6,49 ASXL1,15 and RUNX145). Furthermore, comprehensive sequencing studies of well-annotated, homogeneously treated patient cohorts are needed to understand the clinical implications of integrated mutational profiling in AML. An additional challenge to using mutational analysis for TET2 and DNMT3a in clinical use is identifying a means for rapid molecular testing of these mutations. This challenge may be met by the use of non–polymerase chain reaction–based methods of target enrichment, such as hybrid capture, followed by next-generation sequencing technologies. Moreover, clinical studies evaluating the biochemical consequences of mutations in some of these genes (eg, production of 2-HG in bodily fluids from patients with IDH-mutant AML or increased hydroxymethylcytosine levels in pretreatment blast DNA in patients with TET2/IDH mutant AML) may also prove to be useful in identifying biomarkers. Alternatively, protein-based technologies such as immunohistochemistry or mass spectrometry may be used in the clinical setting to detect the mutant proteins or loss of expression of specific proteins in patients with mutations. An additional area of importance highlighted by these discoveries is the increasing realization that several of these genes encode enzymes or result in alterations in enzymatic activities, which may represent novel, tractable therapeutic targets for patients with AML. This finding may hopefully lead to the development of novel targeted therapeutics for patients with specific genetic alterations in AML. This development may be occurring now with the advent of DOT1L-targeted therapy for leukemic cells with translocations involving MLL1.50,51 Studies to identify whether the neomorphic enzymatic activity of IDH1/2 mutations may be targetable or if the downstream effects of TET2 mutations can be targeted are ongoing and may lead to the development of rational epigenetic therapies that improve outcomes for patients with AML.
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27
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Phenethyl isothiocyanate exhibits antileukemic activity in vitro and in vivo by inactivation of Akt and activation of JNK pathways. Cell Death Dis 2011; 2:e140. [PMID: 21472003 PMCID: PMC3122055 DOI: 10.1038/cddis.2011.22] [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: 11/25/2022]
Abstract
Effects of phenethyl isothiocyanate (PEITC) have been investigated in human leukemia cells (U937, Jurkat, and HL-60) as well as in primary human acute myeloid leukemia (AML) cells in relation to apoptosis and cell signaling events. Exposure of cells to PEITC resulted in pronounced increase in the activation of caspase-3, -8, -9, cleavage/degradation of PARP, and apoptosis in dose- and time-dependent manners. These events were accompanied by the caspase-independent downregulation of Mcl-1, inactivation of Akt, as well as activation of Jun N-terminal kinase (JNK). Inhibition of PI3K/Akt by LY294002 significantly enhanced PEITC-induced apoptosis. Conversely, enforced activation of Akt by a constitutively active Akt construct markedly abrogated PEITC-mediated JNK activation, Mcl-1 downregulation, caspase activation, and apoptosis, and also interruption of the JNK pathway by pharmacological or genetically (e.g., siRNA) attenuated PEITC-induced apoptosis. Finally, administration of PEITC markedly inhibited tumor growth and induced apoptosis in U937 xenograft model in association with inactivation of Akt, activation of JNK, as well as downregulation of Mcl-1. Taken together, these findings represent a novel mechanism by which agents targeting Akt/JNK/Mcl-1 pathway potentiate PEITC lethality in transformed and primary human leukemia cells and inhibitory activity of tumor growth of U937 xenograft model.
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Abstract
Although classical mutations in genes such as PIK3CA and PTEN occur at a relatively low frequency in haematological malignancies, activation of PI3K signalling is often detected in these tumours. In some conditions, for example acute myeloid leukaemia (AML), this is due to activating mutations of upstream regulators such as the FLT3 tyrosine kinase or RAS. Primary tumour cells taken from patients with AML, acute lymphoblastic leukaemia, chronic lymphocytic leukaemia and multiple myeloma show varying levels of sensitivity to PI3K and mTOR inhibitors. The challenge now is to conduct high quality trials with novel agents that target these pathways to establish the level of clinical response and to identify those subsets of patients that are more likely to respond.
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Blalock WL, Bavelloni A, Piazzi M, Tagliavini F, Faenza I, Martelli AM, Follo MY, Cocco L. Multiple forms of PKR present in the nuclei of acute leukemia cells represent an active kinase that is responsive to stress. Leukemia 2010; 25:236-45. [PMID: 21072047 DOI: 10.1038/leu.2010.264] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A number of cancers possess constitutive activity of the dsRNA-dependent kinase, PKR. Inhibition of PKR in these cancers leads to tumor cell death. We recently reported the increased presence of PKR phosphorylated on Thr451 (p-T451 PKR) in clinical samples from myelodysplastic syndrome (MDS) patients and acute leukemia cell lines. Whereas p-T451 PKR in low-risk patient samples or PTEN-positive acute leukemia cell lines was mostly cytoplasmic, in high-risk patient samples and acute leukemia cell lines deficient in PTEN, p-T451 PKR was mainly nuclear. As nuclear activity of PKR has not been previously characterized, we examined the status of nuclear PKR in acute leukemia cell lines. Using antibodies to N-terminus, C-terminus and the kinase domain in conjunction with a proteomics approach, we found that PKR exists in diverse molecular weight forms in the nucleus. Analysis of PKR transcripts by reverse transcriptase-PCR, and PKR-derived peptides by MS/MS revealed that these forms were the result of post-translational modifications (PTMs). Biochemical analysis demonstrated that nuclear PKR is an active kinase that can respond to stress. Given the association of PKR with PTEN and the Fanconi complex, these results indicate that PKR likely has other previously unrecognized roles in nuclear signaling that may contribute to leukemic development.
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Affiliation(s)
- W L Blalock
- Department of Human Anatomical Sciences, University of Bologna, Bologna, Italy
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30
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Response. Exp Hematol 2010. [DOI: 10.1016/j.exphem.2010.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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31
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Abstract
The tumor suppressor gene phosphatase and tensin homolog (PTEN) is inactivated in many human cancers. However, it is unknown whether PTEN functions as a tumor suppressor in human Philadelphia chromosome-positive leukemia that includes chronic myeloid leukemia (CML) and B-cell acute lymphoblastic leukemia (B-ALL) and is induced by the BCR-ABL oncogene. By using our mouse model of BCR-ABL-induced leukemias, we show that Pten is down-regulated by BCR-ABL in leukemia stem cells in CML and that PTEN deletion causes acceleration of CML development. In addition, overexpression of PTEN delays the development of CML and B-ALL and prolongs survival of leukemia mice. PTEN suppresses leukemia stem cells and induces cell-cycle arrest of leukemia cells. Moreover, PTEN suppresses B-ALL development through regulating its downstream gene Akt1. These results demonstrate a critical role of PTEN in BCR-ABL-induced leukemias and suggest a potential strategy for the treatment of Philadelphia chromosome-positive leukemia.
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Mechanistic insight into WEB-2170-induced apoptosis in human acute myelogenous leukemia cells: The crucial role of PTEN. Exp Hematol 2009; 37:1176-1185.e21. [DOI: 10.1016/j.exphem.2009.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 06/29/2009] [Accepted: 07/09/2009] [Indexed: 11/20/2022]
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33
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Gallay N, Dos Santos C, Cuzin L, Bousquet M, Simmonet Gouy V, Chaussade C, Attal M, Payrastre B, Demur C, Récher C. The level of AKT phosphorylation on threonine 308 but not on serine 473 is associated with high-risk cytogenetics and predicts poor overall survival in acute myeloid leukaemia. Leukemia 2009; 23:1029-38. [DOI: 10.1038/leu.2008.395] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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34
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Hu S, Niu H, Minkin P, Orwick S, Shimada A, Inaba H, Dahl GVH, Rubnitz J, Baker SD. Comparison of antitumor effects of multitargeted tyrosine kinase inhibitors in acute myelogenous leukemia. Mol Cancer Ther 2008; 7:1110-20. [PMID: 18483300 DOI: 10.1158/1535-7163.mct-07-2218] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We compared the antitumor activities of the multitargeted tyrosine kinase inhibitors imatinib, sorafenib, and sunitinib to determine which inhibitor is best suited to be used for the treatment of acute myelogenous leukemia (AML). In nine human AML cell lines, sorafenib and sunitinib were more potent inhibitors of cellular proliferation than imatinib (IC50, 0.27 to >40, 0.002-9.1, and 0.007-13 micromol/L for imatinib, sorafenib, and sunitinib, respectively). Sorafenib and sunitinib were potent inhibitors of cells with fms-like tyrosine kinase 3 internal tandem duplication (IC50, 2 and 7 nmol/L) and c-KIT N822K mutations (IC50, 23 and 40 nmol/L). In four cell lines (MV4-11, Kasumi-1, KG-1, and U937) that spanned a range of drug sensitivities, sorafenib and sunitinib had similar activity in apoptosis and cell cycle assays, except that sunitinib did not promote apoptosis in U937 cells. Both drugs inhibited mitogen-activated protein kinase signaling but had no effect on AKT signaling in most of the cell lines tested. Sorafenib was substantially more bound than sunitinib in human plasma (unbound fraction, 0.59% versus 8.4%) and cell culture medium (unbound fraction, 1.3% versus 39%), indicating that sorafenib was more potent than sunitinib and that unbound sorafenib concentrations with activity against most AML cell lines are achievable in vivo. There was more intracellular accumulation of sorafenib than of sunitinib and imatinib in AML cells. Between 1 and 10 micromol/L, sorafenib inhibited the proliferation of six of nine primary AML blast samples by > or =50%. Our results highlight the pharmacologic features of sorafenib that may provide it an advantage in the treatment of AML.
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Affiliation(s)
- Shuiying Hu
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, 332 North Lauderdale Street, DTRC Room D1034, Mail Stop 314, Memphis, TN 38105, USA
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35
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Loriaux MM, Levine RL, Tyner JW, Fröhling S, Scholl C, Stoffregen EP, Wernig G, Erickson H, Eide CA, Berger R, Bernard OA, Griffin JD, Stone RM, Lee B, Meyerson M, Heinrich MC, Deininger MW, Gilliland DG, Druker BJ. High-throughput sequence analysis of the tyrosine kinome in acute myeloid leukemia. Blood 2008; 111:4788-96. [PMID: 18252861 PMCID: PMC2343606 DOI: 10.1182/blood-2007-07-101394] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Accepted: 01/27/2008] [Indexed: 12/20/2022] Open
Abstract
To determine whether aberrantly activated tyrosine kinases other than FLT3 and c-KIT contribute to acute myeloid leukemia (AML) pathogenesis, we used high-throughput (HT) DNA sequence ana-lysis to screen exons encoding the activation loop and juxtamembrane domains of 85 tyrosine kinase genes in 188 AML patients without FLT3 or c-KIT mutations. The screen identified 30 nonsynonymous sequence variations in 22 different kinases not previously reported in single-nucleotide polymorphism (SNP) databases. These included a novel FLT3 activating allele and a previously described activating mutation in MET (METT1010I). The majority of novel sequence variants were stably expressed in factor-dependent Ba/F3 cells. Apart from one FLT3 allele, none of the novel variants showed constitutive phosphorylation by immunoblot analysis and none transformed Ba/F3 cells to factor-independent growth. These findings indicate the majority of these alleles are not potent tyrosine kinase activators in this cellular context and that a significant proportion of nonsynonymous sequence variants identified in HT DNA sequencing screens may not have functional significance. Although some sequence variants may represent SNPs, these data are consistent with recent reports that a significant fraction of such sequence variants are "passenger" rather than "driver" alleles and underscore the importance of functional assessment of candidate disease alleles.
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Affiliation(s)
- Marc M Loriaux
- Division of Hematology and Medical Oncology, Oregon Health & Science University Cancer Institute, Portland, OR 97239, USA
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36
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Zenz T, Döhner K, Denzel T, Döhner H, Stilgenbauer S, Bullinger L. Chronic lymphocytic leukaemia and acute myeloid leukaemia are not associated with AKT1 pleckstrin homology domain (E17K) mutations. Br J Haematol 2008; 141:742-3. [PMID: 18410456 DOI: 10.1111/j.1365-2141.2008.07113.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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37
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Yilmaz OH, Morrison SJ. The PI-3kinase pathway in hematopoietic stem cells and leukemia-initiating cells: a mechanistic difference between normal and cancer stem cells. Blood Cells Mol Dis 2008; 41:73-6. [PMID: 18387833 DOI: 10.1016/j.bcmd.2008.02.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Accepted: 02/15/2008] [Indexed: 10/22/2022]
Abstract
The identification of cancer stem cells in leukemia, breast, brain, colon, and other cancers suggests that many tumors are maintained by stem cells in much the same way as normal tissues are maintained. Because cancer stem cells share remarkable phenotypic and functional similarities with normal stem cells, it may be difficult to identify therapeutic approaches to kill cancer stem cells without killing the normal stem cells in the same tissue. Yet in certain tissues, like the hematopoietic system and gut epithelium, this will be critical as regenerative capacity in these tissues is acutely required for life. Components of the PI-3kinase pathway, including Akt, mTor and FoxO are critical regulators of both normal stem cell function and tumorigenesis. Intriguingly, inactivation of some pathway components, like Pten, has opposite effects on normal hematopoietic stem cells (HSCs) and leukemia-initiating cells. This raises the possibility that drugs targeting this pathway could be more effective at eliminating cancer stem cells while being less toxic against normal stem cells.
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Affiliation(s)
- Omer H Yilmaz
- Howard Hughes Medical Institute, Department of Internal Medicine, and Center for Stem Cell Biology, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, 48109-2216, USA
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38
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Woo KJ, Yoo YH, Park JW, Kwon TK. Bcl-2 attenuates anticancer agents-induced apoptosis by sustained activation of Akt/protein kinase B in U937 cells. Apoptosis 2008; 10:1333-43. [PMID: 16215670 DOI: 10.1007/s10495-005-2763-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Aberrant overexpression of antiapoptotic members of the Bcl-2 protein family contributes to resistance to anticancer therapeutic drugs. Thus, this protein represent attractive target for novel anticancer agents. In the present study, we determined the effect of the anti-apoptosis protein Bcl-2 on caspase-3 activation, PLC-gamma1 degradation and Akt activation during the various anticancer agents-induced apoptosis. Treatment with chrysin for 12 h produced morphological features of apoptosis in U937 cells, which was associated with caspase-3 activation and PLC-gamma1 degradation. Induction of apoptosis was also accompanied by down-regulation of XIAP and inactivation of Akt. Chrysin-induced caspase-3 activation, PLC-gamma1 degradation and apoptosis were significantly attenuated in Bcl-2 overexpressing U937/Bcl-2 cells. Ectopic expression of Bcl-2 appeared to inhibit ceramide-, and Akt specific inhibitor (SH-6)-induced apoptosis by sustained Akt activation. Thus, our findings imply that some of the biological functions of Bcl-2 may be attributed to their ability to inhibit anticancer agents-induced apoptosis through the sustained Akt activation.
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Affiliation(s)
- K J Woo
- Department of Immunology, School of Medicine, Keimyung University, 194 DongSan-Dong Jung-Gu, Taegu 700-712, Korea
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39
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Contributions of the Raf/MEK/ERK, PI3K/PTEN/Akt/mTOR and Jak/STAT pathways to leukemia. Leukemia 2008; 22:686-707. [DOI: 10.1038/leu.2008.26] [Citation(s) in RCA: 293] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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40
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Doepfner KT, Spertini O, Arcaro A. Autocrine insulin-like growth factor-I signaling promotes growth and survival of human acute myeloid leukemia cells via the phosphoinositide 3-kinase/Akt pathway. Leukemia 2007; 21:1921-30. [PMID: 17581609 DOI: 10.1038/sj.leu.2404813] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Insulin-like growth factor (IGF) signaling plays an important role in various human cancers. Therefore, the role of insulin-like growth factor I (IGF-I) signaling in growth and survival of acute myeloid leukemia (AML) cells was investigated. Expression of the IGF-I receptor (IGF-IR) and its ligand IGF-I were detected in a panel of human AML blasts and cell lines. IGF-I and insulin promoted the growth of human AML blasts in vitro and activated the phosphoinositide 3-kinase (PI3K)/Akt and the extracellular signal-regulated kinase (Erk) pathways. IGF-I-stimulated growth of AML blasts was blocked by an inhibitor of the PI3K/Akt pathway. Moreover, downregulation of the class Ia PI3K isoforms p110beta and p110delta by RNA interference impaired IGF-I-stimulated Akt activation, cell growth and survival in AML cells. Proliferation of a panel of AML cell lines and blasts isolated from patients with AML was inhibited by the IGF-IR kinase inhibitor NVP-AEW541 or by an IGF-IR neutralizing antibody. In addition to its antiproliferative effects, NVP-AEW541 sensitized primary AML blasts and cell lines to etoposide-induced apoptosis. Together, our data describe a novel role for autocrine IGF-I signaling in the growth and survival of primary AML cells. IGF-IR inhibitors in combination with chemotherapeutic agents may represent a novel approach to target human AML.
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Affiliation(s)
- K T Doepfner
- Division of Clinical Chemistry and Biochemistry, University Children's Hospital Zurich, Zurich, Switzerland
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41
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McLornan DP, McMullin MF, Johnston P, Longley DB. Molecular mechanisms of drug resistance in acute myeloid leukaemia. Expert Opin Drug Metab Toxicol 2007; 3:363-77. [PMID: 17539744 DOI: 10.1517/17425255.3.3.363] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Resistance to chemotherapy in acute myeloid leukaemia is a major obstacle to a successful outcome for many patients. Often, there is resistance against a broad range of drugs due to multiple, simultaneously active processes. These mechanisms include effects on drug influx and efflux, drug activation/inactivation, DNA repair mechanisms, altered response of end targets, an altered haematopoietic microenvironment and dysfunctional apoptotic pathways. This article reviews the factors that determine leukaemic cell chemosensitivity and discusses the potential for rationally guided therapy.
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Affiliation(s)
- Donal P McLornan
- Medical Research Council Clinical Research Fellow, Queen's University Belfast, Centre for Cancer Research and Cell Biology, BT7 1NN, Northern Ireland, UK
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42
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Martelli AM, Nyåkern M, Tabellini G, Bortul R, Tazzari PL, Evangelisti C, Cocco L. Phosphoinositide 3-kinase/Akt signaling pathway and its therapeutical implications for human acute myeloid leukemia. Leukemia 2006; 20:911-28. [PMID: 16642045 DOI: 10.1038/sj.leu.2404245] [Citation(s) in RCA: 262] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The phosphoinositide 3-kinase (PI3K)/Akt signaling pathway is crucial to many aspects of cell growth, survival and apoptosis, and its constitutive activation has been implicated in the both the pathogenesis and the progression of a wide variety of neoplasias. Hence, this pathway is an attractive target for the development of novel anticancer strategies. Recent studies showed that PI3K/Akt signaling is frequently activated in acute myeloid leukemia (AML) patient blasts and strongly contributes to proliferation, survival and drug resistance of these cells. Upregulation of the PI3K/Akt network in AML may be due to several reasons, including FLT3, Ras or c-Kit mutations. Small molecules designed to selectively target key components of this signal transduction cascade induce apoptosis and/or markedly increase conventional drug sensitivity of AML blasts in vitro. Thus, inhibitory molecules are currently being developed for clinical use either as single agents or in combination with conventional therapies. However, the PI3K/Akt pathway is important for many physiological cellular functions and, in particular, for insulin signaling, so that its blockade in vivo might cause severe systemic side effects. In this review, we summarize the existing knowledge about PI3K/Akt signaling in AML cells and we examine the rationale for targeting this fundamental signal transduction network by means of selective pharmacological inhibitors.
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Affiliation(s)
- A M Martelli
- Cell Signalling Laboratory, Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Sezione di Anatomia Umana, Università di Bologna, Bologna, Italy.
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43
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Gao P, Wange RL, Zhang N, Oppenheim JJ, Howard OMZ. Negative regulation of CXCR4-mediated chemotaxis by the lipid phosphatase activity of tumor suppressor PTEN. Blood 2005; 106:2619-26. [PMID: 15994292 PMCID: PMC1895312 DOI: 10.1182/blood-2004-08-3362] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Accepted: 06/15/2005] [Indexed: 02/02/2023] Open
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a multifunctional tumor suppressor, has been shown to play a regulatory role in cell migration. Dictyostelium discoideum cells lacking PTEN exhibited impaired migration toward chemoattractant gradients. In the present study, we investigated the involvement of PTEN in chemotaxis of mammalian cells by examining PTEN-null Jurkat T cells. We observed that, in contrast to observations made in D discoideum, PTEN-null Jurkat T cells exhibited potent chemotactic responses to the chemokine stromal cell-derived factor 1alpha (SDF-1alpha), indicating that PTEN was not requisite for CXC chemokine receptor 4 (CXCR4)-mediated chemotaxis of Jurkat cells. Conversely, reconstitution of PTEN in Jurkat cells by using a tetracycline (Tet-on)-inducible expression system down-regulated CXCR4-mediated chemotaxis. Furthermore, we established the lipid phosphatase activity of PTEN as essential for its inhibitory effect on chemotaxis. In addition, using PTEN-expressing T-cell lines and primary T cells, we demonstrated that down-regulation of PTEN expression with vector-based small interfering RNAs (siRNAs) enhanced CXCR4-mediated chemotaxis. Based on these results, we conclude that PTEN expression negatively regulates chemotaxis of lymphoid mammalian cells via its lipid phosphatase activity. Our findings may account for the reported increase in metastatic activity of PTEN-null tumor cells.
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Affiliation(s)
- Ping Gao
- Laboratory of Molecular Immunoregulation, Center for Cancer Research, National Cancer Institute-Frederick, PO Box B, Bldg 560, Rm 31-19, Frederick, MD 21702-1201, USA
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44
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Chang H, Qi XY, Claudio J, Zhuang L, Patterson B, Stewart AK. Analysis of PTEN deletions and mutations in multiple myeloma. Leuk Res 2005; 30:262-5. [PMID: 16112193 DOI: 10.1016/j.leukres.2005.07.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 07/10/2005] [Accepted: 07/12/2005] [Indexed: 11/20/2022]
Abstract
Clonal plasma cells from patients with multiple myeloma (MM), plasma cell leukemia (PCL) and human myeloma cell lines (HMCLs) were analyzed for deletions/mutations of the tumor suppressor gene PTEN. By interphase-FISH, hemizygous PTEN deletions were detected in 4 (5.6%) of 71 MM patients, 2 (20%) of 10 PCLs, and 2 (20%) of 10 HMCLs. PTEN deletions were detected in 4 MM patients at diagnosis with stage III disease (Durie-Salmon). Of the six cases with PTEN deletions, 1 MM had a 13q deletion, 1 PCL had a t(11;14), and the other PCL had a t(14;16), a 13q deletion and a p53 deletion. Sequencing analysis did not detect PTEN mutations in 11 primary MM and 5 PCL cases. Our results indicate that alterations of PTEN are uncommon in MM patients, and PTEN deletions tend to occur in advanced disease suggesting that they are secondary, rather than primary, events in the pathogenesis of MM.
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Affiliation(s)
- Hong Chang
- Department of Laboratory Hematology, Princess Margaret Hospital/University Health Network, University of Toronto, Ont., Canada M5G 2M9.
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45
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Agrawal S, Pilarski R, Eng C. Different splicing defects lead to differential effects downstream of the lipid and protein phosphatase activities of PTEN. Hum Mol Genet 2005; 14:2459-68. [PMID: 16014636 DOI: 10.1093/hmg/ddi246] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PTEN, encoding a dual phosphatase tumor suppressor, is mutated in 85 and 65% of individuals with Cowden syndrome (CS) and Bannayan-Riley-Ruvalcaba syndrome (BRRS), respectively. Approximately 23 germline mutations in putative splice sites have been published, but resulting downstream outcome data are limited. We determined splicing defects in PTEN in 40 germline PTEN mutation positive cases and 33 mutation negative cases with classic CS, BRRS and CS- or BRRS-like features. Altered splicing was observed in 4/40 mutation positive probands and 2/33 mutation negative probands. We then sought to characterize the transcriptional and biochemical outcomes of the five distinct splice-site mutations, which led to the skipping of exon 3, 4 or 6. Two mutation negative BRRS patients also showed exon 3 skipping, and later, genomic sequencing revealed a mutation deep in intron 2. The splice-site mutations leading to the deletions of exon 3, 4 or 6 resulted in reduced dual phosphatase activities of PTEN. Deletion of exon 4 was associated with severely reduced lipid phosphatase activity, whereas exon 3 skipping resulted in markedly reduced protein phosphatase activity. In addition, exon 3 deleted transcript and protein were stable and localized to the nucleus more efficiently than the wild-type PTEN. In contrast, exon 4 skipping resulted in unstable transcripts and severely truncated unstable PTEN protein lacking its phosphatase domain. We have not only described for the first time, the effect of a deep intronic/branch-site mutation on exon skipping in PTEN but also found that different splice-site mutations resulting in the deletion of different exons lead to distinct outcomes.
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Affiliation(s)
- Shipra Agrawal
- Clinical Cancer Genetics Program, Human Cancer Genetics Program, Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
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46
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Barjesteh van Waalwijk van Doorn-Khosrovani S, Spensberger D, de Knegt Y, Tang M, Löwenberg B, Delwel R. Somatic heterozygous mutations in ETV6 (TEL) and frequent absence of ETV6 protein in acute myeloid leukemia. Oncogene 2005; 24:4129-37. [PMID: 15806161 DOI: 10.1038/sj.onc.1208588] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2004] [Revised: 01/14/2005] [Accepted: 01/27/2005] [Indexed: 01/11/2023]
Abstract
ETV6 (ets translocation variant gene 6) TEL (translocation ets leukemia), encoding a transcriptional repressor, is involved in various translocations associated with human malignancies. Strikingly, the nonrearranged ETV6 allele is often deleted or inactivated in cells harboring these translocations. Although ETV6 translocations are infrequent in acute myeloid leukemia (AML), mutations or deregulated expression of ETV6 may contribute to leukemogenesis. To investigate the involvement of ETV6 in AML, we analysed 300 newly diagnosed patients for mutations in the coding region of the gene. Furthermore, we studied protein expression in 77 patients using two ETV6-specific antibodies. Five somatic heterozygous mutations were detected, which affected either the homodimerization- or the DNA-binding domain of ETV6. The proteins translated from the cDNAs of these mutants were unable to repress transcription and showed dominant-negative effects. In addition, we demonstrate that one-third of AML patients have deficient ETV6 protein expression, which is not related to ETV6 mRNA expression levels. In conclusion, we demonstrate that ETV6 abnormalities are not restricted to translocations and occur more frequently in AML than previously thought. Additional comprehensive studies are required to define the clinical consequence of ETV6 loss of function in AML.
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Min YH, Cheong JW, Lee MH, Kim JY, Lee ST, Hahn JS, Ko YW. Elevated S-Phase Kinase-Associated Protein 2 Protein Expression in Acute Myelogenous Leukemia. Clin Cancer Res 2004; 10:5123-30. [PMID: 15297415 DOI: 10.1158/1078-0432.ccr-04-0136] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The F-box protein S-phase kinase-associated protein 2 (Skp2) positively regulates the G(1)-S phase transition by controlling the stability of several G(1) regulators, such as p27Kip1. However, the clinical significance of Skp2 in patients with acute myelogenous leukemia (AML) remains unknown. EXPERIMENTAL DESIGN We examined the clinical and biological significance of Skp2 expression in AML and evaluated the relationship between Skp2 and p27Kip1 expression and phosphatase and tensin homologue (PTEN) phosphorylation. RESULTS Western blot analysis showed that high Skp2 expression was observed in 57 (57.6%) cases and significantly correlated with unfavorable cytogenetics (P = 0.035) but not with age, white blood cell count, serum lactic dehydrogenase level, and the French-American-British subtype. An inverse correlation was not observed between Skp2 and p27Kip1 expression. However, p27Kip1 protein was preferentially localized to cytoplasm in the high-Skp2-expression group. The cytoplasmic to nuclear ratio of p27Kip1 expression was significantly correlated with the levels of Skp2 expression (P < 0.001). The frequency of PTEN phosphorylation was significantly higher in the high-Skp2-expression group compared with the low- Skp2-expression group (P = 0.035). The Skp2 overexpression was significantly associated with shorter disease-free survival and overall survival (P = 0.0386 and P = 0.0369, respectively). Multivariate analysis showed that Skp2 expression was an independent prognostic factor both in the disease-free survival and overall survival. CONCLUSION These findings suggest that Skp2 expression is an independent marker for a poor prognosis in AML. The presence of a positive correlation between Skp2 and phosphorylated PTEN suggests that an aberration in the PTEN/Skp2 signaling pathway might be operating in AML.
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Affiliation(s)
- Yoo Hong Min
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
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48
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Recher C, Ysebaert L, Beyne-Rauzy O, Mansat-De Mas V, Ruidavets JB, Cariven P, Demur C, Payrastre B, Laurent G, Racaud-Sultan C. Expression of focal adhesion kinase in acute myeloid leukemia is associated with enhanced blast migration, increased cellularity, and poor prognosis. Cancer Res 2004; 64:3191-7. [PMID: 15126359 DOI: 10.1158/0008-5472.can-03-3005] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase playing an important role in cell motility and survival. However, very little is known about FAK in normal and leukemic myeloid cells. In this study, FAK protein expression and mRNA were detected in 25 of 60 cases (42%) of acute myeloid leukemia (AML). Whereas FAK was expressed in 46% of CD34+ AML cells, it was not detected in normal purified CD34+ cells. Conversely, the FAK homologue proline-rich tyrosine kinase 2 (PYK2) was found to be expressed both in normal and leukemic myeloid cells. When expressed, FAK displayed phosphorylation on Tyr-397, an important step for its activation. Moreover, FAK expression was correlated with the phosphorylation of PYK2 on Tyr-881, a critical site for the PYK2 function in cell migration. FAK+ AML cells displayed significantly higher migration capacities and resistance to daunorubicin, compared with FAK- cells. The implication of FAK in both cell motility and drug resistance was demonstrated by small interfering RNA experiments with the FAK-positive KG1 cell line. However, adhesion on fibronectin efficiently protected FAK- AML cells from daunorubicin-mediated killing, suggesting that cellular adhesion mediated-drug resistance is not mediated by FAK. Finally, in a retrospective cohort of 60 AML patients, FAK expression was significantly correlated with high blast cell count, early death, and shorter survival rate. Altogether, this study shows that FAK is aberrantly expressed and activated in about half of the cases of AML and suggests that FAK may contribute to the regulation of AML cell transit from the marrow to blood compartment and that it may influence clinical outcome.
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Affiliation(s)
- Christian Recher
- Institut National de la Santé et de la Recherche Médicale Unité 563, Département d'Oncogenèse et Signalisation Cellulaire dans les Cellules Hématopoïétiques, Institut Fédératif de Recherche (IFR)30, Toulouse, France
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49
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Cappellini A, Tabellini G, Zweyer M, Bortul R, Tazzari PL, Billi AM, Falà F, Cocco L, Martelli AM. The phosphoinositide 3-kinase/Akt pathway regulates cell cycle progression of HL60 human leukemia cells through cytoplasmic relocalization of the cyclin-dependent kinase inhibitor p27(Kip1) and control of cyclin D1 expression. Leukemia 2003; 17:2157-67. [PMID: 12931221 DOI: 10.1038/sj.leu.2403111] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The serine/threonine protein kinase Akt, a downstream effector of phosphoinositide 3-kinase (PI3K), plays a pivotal role in tumorigenesis because it affects the growth and survival of cancer cells. Several laboratories have demonstrated that Akt inhibits transcriptional activation of a number of related forkhead transcription factors now referred to as FoxO1, FoxO3, and FoxO4. Akt-regulated forkhead transcription factors are involved in the control of the expression of both the cyclin-dependent kinase (cdk) inhibitor p27(Kip1) and proapoptotic Bim protein. Very little information is available concerning the importance of the PI3K/Akt pathway in HL60 human leukemia cells. Here, we present our findings showing that the PI3K/Akt axis regulates cell cycle progression of HL60 cells through multiple mechanisms also involving the control of FoxO1 and FoxO3. To this end, we took advantage of a HL60 cell clone (HL60AR cells) with a constitutively activated PI3K/Akt axis. When compared with parental (PT) HL60 cells, HL60AR cells displayed higher levels of phosphorylated FoxO1 and FoxO3. In AR cells forkhead factors localized predominantly in the cytoplasm, whereas in PT cells they were mostly nuclear. AR cells proliferated faster than PT cells and showed a lower amount of the cdk inhibitor p27(Kip1), which was mainly found in the cytoplasm and was hyperphosphorylated on threonine residues. AR cells also displayed higher levels of cyclin D1 and phosphorylated p110 Retinoblastoma protein. The protein levels of cdk2, cdk4, and cdk6 were not altered in HL60AR cells, whereas the activities of both ckd2 and cdk6 were higher in AR than in PT cells. These results show that in HL60 cells the PI3K/Akt signaling pathway may be involved in the control of the cell cycle progression most likely through mechanisms involving the activation of forkhead transcription factors.
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Affiliation(s)
- A Cappellini
- Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Sezione di Anatomia, Cell Signalling Laboratory, Università di Bologna, Italy
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50
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Martelli AM, Tazzari PL, Tabellini G, Bortul R, Billi AM, Manzoli L, Ruggeri A, Conte R, Cocco L. A new selective AKT pharmacological inhibitor reduces resistance to chemotherapeutic drugs, TRAIL, all-trans-retinoic acid, and ionizing radiation of human leukemia cells. Leukemia 2003; 17:1794-805. [PMID: 12970779 DOI: 10.1038/sj.leu.2403044] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It is now well established that the reduced capacity of tumor cells of undergoing cell death through apoptosis plays a key role both in the pathogenesis of cancer and in therapeutic treatment failure. Indeed, tumor cells frequently display multiple alterations in signal transduction pathways leading to either cell survival or apoptosis. In mammals, the pathway based on phosphoinositide 3-kinase (PI3K)/Akt conveys survival signals of extreme importance and its downregulation, by means of pharmacological inhibitors of PI3K, considerably lowers resistance to various types of therapy in solid tumors. We recently described an HL60 leukemia cell clone (HL60AR cells) with a constitutively active PI3K/Akt pathway. These cells were resistant to multiple chemotherapeutic drugs, all-trans-retinoic acid (ATRA), and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Treatment with two pharmacological inhibitors of PI3K, wortmannin and Ly294002, restored sensitivity of HL60AR cells to the aforementioned treatments. However, these inhibitors have some drawbacks that may severely limit or impede their clinical use. Here, we have tested whether or not a new selective Akt inhibitor, 1L-6-hydroxymethyl-chiro-inositol 2(R)-2-O-methyl-3-O-octadecylcarbonate (Akt inhibitor), was as effective as Ly294002 in lowering the sensitivity threshold of HL60 cells to chemotherapeutic drugs, TRAIL, ATRA, and ionizing radiation. Our findings demonstrate that, at a concentration which does not affect PI3K activity, the Akt inhibitor markedly reduced resistance of HL60AR cells to etoposide, cytarabine, TRAIL, ATRA, and ionizing radiation. This effect was likely achieved through downregulation of expression of antiapoptotic proteins such as c-IAP1, c-IAP2, cFLIP(L), and of Bad phosphorylation on Ser 136. The Akt inhibitor did not influence PTEN activity. At variance with Ly294002, the Akt inhibitor did not negatively affect phosphorylation of protein kinase C-zeta and it was less effective in downregulating p70S6 kinase (p70S6K) activity. The Akt inhibitor increased sensitivity to apoptotic inducers of K562 and U937, but not of MOLT-4, leukemia cells. Overall, our results indicate that selective Akt pharmacological inhibitors might be used in the future for enhancing the sensitivity of leukemia cells to therapeutic treatments that induce apoptosis or for overcoming resistance to these treatments.
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Affiliation(s)
- A M Martelli
- Dipartimento di Scienze Anatomiche Umane e Fisiopatologia dell'Apparato Locomotore, Sezione di Anatomia, Cell Signalling Laboratory, Università di Bologna, Bologna, Italy
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