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Lima MP, Hornsby BD, Lim CS, Cheatham TE. Molecular Modeling of Single- and Double-Hydrocarbon-Stapled Coiled-Coil Inhibitors against Bcr-Abl: Toward a Treatment Strategy for CML. J Phys Chem B 2024; 128:6476-6491. [PMID: 38951498 PMCID: PMC11247501 DOI: 10.1021/acs.jpcb.4c02699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 06/10/2024] [Accepted: 06/11/2024] [Indexed: 07/03/2024]
Abstract
The chimeric oncoprotein Bcr-Abl is the causative agent of virtually all chronic myeloid leukemias and a subset of acute lymphoblastic leukemias. As a result of the so-called Philadelphia chromosome translocation t(9;22), Bcr-Abl manifests as a constitutively active tyrosine kinase, which promotes leukemogenesis by activation of cell cycle signaling pathways. Constitutive and oncogenic activation is mediated by an N-terminal coiled-coil oligomerization domain in Bcr (Bcr-CC), presenting a therapeutic target for inhibition of Bcr-Abl activity toward the treatment of Bcr-Abl+ leukemias. Previously, we demonstrated that a rationally designed Bcr-CC mutant, CCmut3, exerts a dominant negative effect upon Bcr-Abl activity by preferential oligomerization with Bcr-CC. Moreover, we have shown that conjugation to a leukemia-specific cell-penetrating peptide (CPP-CCmut3) improves intracellular delivery and activity. However, our full-length CPP-CCmut3 construct (81 aa) is encumbered by an intrinsically high degree of conformational variability and susceptibility to proteolytic degradation relative to traditional small-molecule therapeutics. Here, we iterate a new generation of CCmut3 inhibitors against Bcr-CC-mediated Bcr-Abl assembly designed to address these constraints through incorporation of all-hydrocarbon staples spanning i and i + 7 positions in α-helix 2 (CPP-CCmut3-st). We utilize computational modeling and biomolecular simulation to evaluate single- and double-stapled CCmut3 candidates in silico for dynamics and binding energetics. We further model a truncated system characterized by the deletion of α-helix 1 and the flexible loop linker, which are known to impart high conformational variability. To study the impact of the N-terminal cyclic CPP toward model stability and inhibitor activity, we also model the full-length and truncated systems devoid of the CPP, with a cyclized CPP, and with an open-configuration CPP, for a total of six systems that comprise our library. From this library, we present lead-stapled peptide candidates to be synthesized and evaluated experimentally as our next iteration of inhibitors against Bcr-Abl.
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MESH Headings
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/metabolism
- Fusion Proteins, bcr-abl/chemistry
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Humans
- Protein Kinase Inhibitors/chemistry
- Protein Kinase Inhibitors/pharmacology
- Protein Kinase Inhibitors/metabolism
- Models, Molecular
- Molecular Dynamics Simulation
- Antineoplastic Agents/chemistry
- Antineoplastic Agents/pharmacology
- Cell-Penetrating Peptides/chemistry
- Cell-Penetrating Peptides/pharmacology
- Cell-Penetrating Peptides/metabolism
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Affiliation(s)
- Maria
Carolina P. Lima
- Department
of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Braxten D. Hornsby
- Department
of Molecular Pharmaceutics, University of
Utah, Salt Lake City, Utah 84112, United States
| | - Carol S. Lim
- Department
of Molecular Pharmaceutics, University of
Utah, Salt Lake City, Utah 84112, United States
| | - Thomas E. Cheatham
- Department
of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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2
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Lima MCP, Hornsby BD, Lim CS, Cheatham TE. Computational Modeling of Stapled Coiled-Coil Inhibitors Against Bcr-Abl: Toward a Treatment Strategy for CML. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.15.566894. [PMID: 38014060 PMCID: PMC10680756 DOI: 10.1101/2023.11.15.566894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The chimeric oncoprotein Bcr-Abl is the causative agent of virtually all chronic myeloid leukemias (CML) and a subset of acute lymphoblastic leukemias (ALL). As a result of the so-called Philadelphia Chromosome translocation t(9;22), Bcr-Abl manifests as a constitutively active tyrosine kinase which promotes leukemogenesis by activation of cell cycle signaling pathways. Constitutive and oncogenic activation is mediated by an N-terminal coiled-coil oligomerization domain in Bcr (Bcr-CC), presenting a therapeutic target for inhibition of Bcr-Abl activity toward the treatment of Bcr-Abl+ leukemias. Previously, we demonstrated that a rationally designed Bcr-CC mutant, CCmut3, exerts a dominant negative effect upon Bcr-Abl activity by preferential oligomerization with Bcr-CC. Moreover, we have shown conjugation to a leukemia-specific cell-penetrating peptide (CPP-CCmut3) improves intracellular delivery and activity. However, our full-length CPP-CCmut3 construct (81 aa) is encumbered by an intrinsically high degree of conformational variability and susceptibility to proteolytic degradation, relative to traditional small molecule therapeutics. Here, we iterate a new generation of our inhibitor against Bcr-CC mediated Bcr-Abl assembly that is designed to address these constraints through incorporation of all-hydrocarbon staples spanning i, i + 7 positions in helix α2 (CPP-CCmut3-st). We utilize computational modeling and biomolecular simulation to design and characterize single and double staple candidates in silico, evaluating binding energetics and building upon our seminal work modeling single hydrocarbon staples when applied to a truncated Bcr-CC sequence. This strategy enables us to efficiently build, characterize, and screen lead single/double stapled CPP-CCmut3-st candidates for experimental studies and validation in vitro and in vivo. In addition to full-length CPP-CCmut, we model a truncated system characterized by deletion of helix α1 and the flexible-loop linker, which are known to impart high conformational variability. To study the impact of the N-terminal cyclic CPP toward model stability and inhibitor activity, we also model the full-length and truncated systems without CPP, with cyclized CPP, and with linear CPP, for a total of six systems which comprise our library. From this library, we present lead stapled peptide candidates to be synthesized and evaluated experimentally as our next-generation inhibitors against Bcr-Abl.
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Affiliation(s)
- Maria Carolina P. Lima
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Braxten D. Hornsby
- Department of Molecular Pharmaceutics, University of Utah, Salt Lake City, Utah 84112, United States
| | - Carol S. Lim
- Department of Molecular Pharmaceutics, University of Utah, Salt Lake City, Utah 84112, United States
| | - Thomas E. Cheatham
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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3
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Liu Y, Zhang M, Jang H, Nussinov R. Higher-order interactions of Bcr-Abl can broaden chronic myeloid leukemia (CML) drug repertoire. Protein Sci 2023; 32:e4504. [PMID: 36369657 PMCID: PMC9795542 DOI: 10.1002/pro.4504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/31/2022] [Accepted: 11/06/2022] [Indexed: 11/14/2022]
Abstract
Bcr-Abl, a nonreceptor tyrosine kinase, is associated with leukemias, especially chronic myeloid leukemia (CML). Deletion of Abl's N-terminal region, to which myristoyl is linked, renders the Bcr-Abl fusion oncoprotein constitutively active. The substitution of Abl's N-terminal region by Bcr enables Bcr-Abl oligomerization. Oligomerization is critical: it promotes clustering on the membrane, which is essential for potent MAPK signaling and cell proliferation. Here we decipher the Bcr-Abl specific, step-by-step oligomerization process, identify a specific packing surface, determine exactly how the process is structured and identify its key elements. Bcr's coiled coil (CC) domain at the N-terminal controls Bcr-Abl oligomerization. Crystallography validated oligomerization via Bcr-Abl dimerization between two Bcr CC domains, with tetramerization via tight packing between two binary assemblies. However, the structural principles guiding Bcr CC domain oligomerization are unknown, hindering mechanistic understanding and drugs exploiting it. Using molecular dynamics (MD) simulations, we determine that the binary complex of the Bcr CC domain serves as a basic unit in the quaternary complex providing a specific surface for dimer-dimer packing and higher-order oligomerization. We discover that the small α1-helix is the key. In the binary assembly, the helix forms interchain aromatic dimeric packing, and in the quaternary assembly, it contributes to the specific dimer-dimer packing. Our mechanism is supported by the experimental literature. It offers the key elements controlling this process which can expand the drug discovery strategy, including by Bcr CC-derived peptides, and candidate residues for small covalent drugs, toward quenching oligomerization, supplementing competitive and allosteric tyrosine kinase inhibitors.
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Affiliation(s)
- Yonglan Liu
- Cancer Innovation LaboratoryNational Cancer InstituteFrederickMarylandUSA
| | - Mingzhen Zhang
- Computational Structural Biology SectionFrederick National Laboratory for Cancer ResearchFrederickMarylandUSA
| | - Hyunbum Jang
- Computational Structural Biology SectionFrederick National Laboratory for Cancer ResearchFrederickMarylandUSA
| | - Ruth Nussinov
- Computational Structural Biology SectionFrederick National Laboratory for Cancer ResearchFrederickMarylandUSA,Department of Human Molecular Genetics and BiochemistrySackler School of Medicine, Tel Aviv UniversityTel AvivIsrael
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4
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Selection-free endogenous tagging of cell lines by bicistronic co-expression of the surface antigen NGFR. MethodsX 2022; 9:101929. [DOI: 10.1016/j.mex.2022.101929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/13/2022] [Indexed: 11/19/2022] Open
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5
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Downes CEJ, McClure BJ, McDougal DP, Heatley SL, Bruning JB, Thomas D, Yeung DT, White DL. JAK2 Alterations in Acute Lymphoblastic Leukemia: Molecular Insights for Superior Precision Medicine Strategies. Front Cell Dev Biol 2022; 10:942053. [PMID: 35903543 PMCID: PMC9315936 DOI: 10.3389/fcell.2022.942053] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/16/2022] [Indexed: 11/13/2022] Open
Abstract
Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer, arising from immature lymphocytes that show uncontrolled proliferation and arrested differentiation. Genomic alterations affecting Janus kinase 2 (JAK2) correlate with some of the poorest outcomes within the Philadelphia-like subtype of ALL. Given the success of kinase inhibitors in the treatment of chronic myeloid leukemia, the discovery of activating JAK2 point mutations and JAK2 fusion genes in ALL, was a breakthrough for potential targeted therapies. However, the molecular mechanisms by which these alterations activate JAK2 and promote downstream signaling is poorly understood. Furthermore, as clinical data regarding the limitations of approved JAK inhibitors in myeloproliferative disorders matures, there is a growing awareness of the need for alternative precision medicine approaches for specific JAK2 lesions. This review focuses on the molecular mechanisms behind ALL-associated JAK2 mutations and JAK2 fusion genes, known and potential causes of JAK-inhibitor resistance, and how JAK2 alterations could be targeted using alternative and novel rationally designed therapies to guide precision medicine approaches for these high-risk subtypes of ALL.
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Affiliation(s)
- Charlotte EJ. Downes
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Barbara J. McClure
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Daniel P. McDougal
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA, Australia
- Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, SA, Australia
| | - Susan L. Heatley
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
- Australian and New Zealand Children’s Oncology Group (ANZCHOG), Clayton, VIC, Australia
| | - John B. Bruning
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA, Australia
- Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, Adelaide, SA, Australia
| | - Daniel Thomas
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
| | - David T. Yeung
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
- Department of Haematology, Royal Adelaide Hospital and SA Pathology, Adelaide, SA, Australia
| | - Deborah L. White
- Blood Cancer Program, Precision Cancer Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
- School of Biological Sciences, Faculty of Sciences, University of Adelaide, Adelaide, SA, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
- Australian and New Zealand Children’s Oncology Group (ANZCHOG), Clayton, VIC, Australia
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6
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Ma B, Feng H, Feng C, Liu Y, Zhang H, Wang J, Wang W, He P, Niu F. Kill Two Birds with One Stone: A Multifunctional Dual-Targeting Protein Drug to Overcome Imatinib Resistance in Philadelphia Chromosome-Positive Leukemia. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2104850. [PMID: 35239999 PMCID: PMC9069375 DOI: 10.1002/advs.202104850] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 01/26/2022] [Indexed: 06/07/2023]
Abstract
The Bcr/Abl plays a central role in Philadelphia chromosome-positive (Ph+) leukemia because of the constitutively activated Abl tyrosine kinase and its downstream pathways. Currently, the clinical treatment of imatinib-resistant patients with tyrosine kinase inhibitors is severely limited by drug resistance and adverse effects. Herein, a dual-targeting proteolysis-targeting chimera (PROTAC) protein drug, termed PMI Bcr/Abl-R6, is designed by engrafting an MDM2/p53 inhibition peptide sequence onto the Bcr/Abl tetramerization domain. PMI Bcr/Abl-R6, harboring a Bcr/Abl targeting sequence and an MDM2 binding sequence, acts as a PROTAC drug in Ph+ leukemia cells. Its dual-targeting constitution suggests that PMI Bcr/Abl-R6 designs to target the tetramerization domain instead of the Abl kinase domain, therefore has the potential to overcome drug resistance mutations in the kinase domain. The efficient ability of PMI Bcr/Abl-R6 is demonstrated to simultaneously induce Bcr/Abl degradation and activate the p53 pathway. PMI Bcr/Abl-R6 has the potential to overcome drug resistance in Ph+ leukemias by multiple mechanisms.
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Affiliation(s)
- Bohan Ma
- Department of UrologyThe First Affiliated HospitalXi'an Jiaotong UniversityXi'an710061China
| | - Hui Feng
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Chao Feng
- Department of EndocrinologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Yi Liu
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Hailing Zhang
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Jincheng Wang
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Wenjuan Wang
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Pengcheng He
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
| | - Fan Niu
- Department of HematologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an710061China
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7
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Al Hamad M. Contribution of BCR-ABL molecular variants and leukemic stem cells in response and resistance to tyrosine kinase inhibitors: a review. F1000Res 2022; 10:1288. [PMID: 35284066 PMCID: PMC8886173 DOI: 10.12688/f1000research.74570.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/08/2022] [Indexed: 11/20/2022] Open
Abstract
Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm generated by reciprocal chromosomal translocation, t (9; 22) (q34; q11) in the transformed hematopoietic stem cell. Tyrosine kinase inhibitors (TKIs) target the mature proliferating BCR-ABL cells, the major CML driver, and increase overall and disease-free survival. However, mutant clones, pre-existing or due to therapy, develop resistance against TKIs. BCR-ABL1 oncoprotein activates various molecular pathways including the RAS/RAF/MEK/ERK pathway, JAK2/STAT pathway, and PI3K/AKT/mTOR pathway. Stimulation of these pathways in TKI resistant CML patients, make them a new target. Moreover, a small proportion of CML cells, leukemic stem cells (LSCs), persist during the TKI therapy and sustain the disease in the patient. Engraftment of LSCs in the bone marrow niche and dysregulation of miRNA participate greatly in the TKI resistance. Current efforts are needed for determining the reason behind TKI resistance, identification, and elimination of CML LSC might be of great need for cancer cure.
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Affiliation(s)
- Mohammad Al Hamad
- Department of Pathology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Dammam, 31441, Saudi Arabia
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8
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Al Hamad M. Contribution of BCR-ABL molecular variants and leukemic stem cells in response and resistance to tyrosine kinase inhibitors: a review. F1000Res 2021; 10:1288. [PMID: 35284066 PMCID: PMC8886173 DOI: 10.12688/f1000research.74570.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/08/2022] [Indexed: 08/28/2023] Open
Abstract
Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm generated by reciprocal chromosomal translocation, t (9; 22) (q34; q11) in the transformed hematopoietic stem cell. Tyrosine kinase inhibitors (TKIs) target the mature proliferating BCR-ABL cells, the major CML driver, and increase overall and disease-free survival. However, mutant clones, pre-existing or due to therapy, develop resistance against TKIs. BCR-ABL1 oncoprotein activates various molecular pathways including the RAS/RAF/MEK/ERK pathway, JAK2/STAT pathway, and PI3K/AKT/mTOR pathway. Stimulation of these pathways in TKI resistant CML patients, make them a new target. Moreover, a small proportion of CML cells, leukemic stem cells (LSCs), persist during the TKI therapy and sustain the disease in the patient. Engraftment of LSCs in the bone marrow niche and dysregulation of miRNA participate greatly in the TKI resistance. Current efforts are needed for determining the reason behind TKI resistance, identification, and elimination of CML LSC might be of great need for cancer cure.
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Affiliation(s)
- Mohammad Al Hamad
- Department of Pathology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Dammam, 31441, Saudi Arabia
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9
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Hirai N, Sasaki T, Okumura S, Minami Y, Chiba S, Ohsaki Y. Monomerization of ALK Fusion Proteins as a Therapeutic Strategy in ALK-Rearranged Non-small Cell Lung Cancers. Front Oncol 2020; 10:419. [PMID: 32300555 PMCID: PMC7142238 DOI: 10.3389/fonc.2020.00419] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 03/10/2020] [Indexed: 11/21/2022] Open
Abstract
Objective: Oncogenic echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) (EML4-ALK) fusion proteins found in non-small cell lung cancers (NSCLC) are constitutively phosphorylated and activated by dimerization via the coiled-coil domain (cc) within EML4. Here, we investigated whether disruption of ALK fusion protein oligomerization via competitive cc mimetic compounds could be a therapeutic strategy for EML4-ALK NSCLC. Methods: A Ba/F3 cell model was created that expressed an ALK intracellular domain in which the dimer/monomer state is ligand-regulated. This novel cell model was used to investigate the effect of disrupting ALK fusion protein oligomerization on tumor cell growth in vitro and in vivo using nude mice. Subsequently, the antiproliferative effects of endogenous cc domain co-expression and mimetic cc peptides were assayed in EML4-ALK cancer cell lines. Results: Cells induced to express monomeric ALK in vitro did not survive. When transplanted into mice, induction of monomers abrogated tumor formation. Using a fluorescent protein system to quantify protein-protein interactions of EML4-ALK and EML4cc, we demonstrated that co-expression of EML4cc suppressed EML4-ALK assembly concomitant with decreasing the rate of tumor growth in vitro and in vivo. In EML4-ALK cancer cell lines, administration of synthetic EML4cc peptide elicited a decrease of phosphorylation of ALK leading to reduction in tumor cell growth. Conclusions: Our findings support the monomerization of ALK fusion proteins using EML4cc peptides for competitive inhibition of dimerization as a promising therapeutic strategy for EML4-ALK NSCLC. Further studies are warranted to explore the use of specific cc peptide as a therapeutic option for other lung cancers harboring driver fusion genes containing a cc or oligomerization domain within the fusion partner.
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Affiliation(s)
- Noriko Hirai
- Respiratory Center, Asahikawa Medical University Hospital, Asahikawa, Japan
| | - Takaaki Sasaki
- Respiratory Center, Asahikawa Medical University Hospital, Asahikawa, Japan
| | - Shunsuke Okumura
- Respiratory Center, Asahikawa Medical University Hospital, Asahikawa, Japan
| | - Yoshinori Minami
- Respiratory Center, Asahikawa Medical University Hospital, Asahikawa, Japan
| | - Shinichi Chiba
- Center for Advanced Research and Education, Asahikawa Medical University, Asahikawa, Japan
| | - Yoshinobu Ohsaki
- Respiratory Center, Asahikawa Medical University Hospital, Asahikawa, Japan
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10
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Cornillie SP, Bruno BJ, Lim CS, Cheatham TE. Computational Modeling of Stapled Peptides toward a Treatment Strategy for CML and Broader Implications in the Design of Lengthy Peptide Therapeutics. J Phys Chem B 2018. [DOI: 10.1021/acs.jpcb.8b01014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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11
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Demirel Ö, Balló O, Reddy PNG, Vakhrusheva O, Zhang J, Eichler A, Fernandes R, Badura S, Serve H, Brandts C. SOCS1 function in BCR-ABL mediated myeloproliferative disease is dependent on the cytokine environment. PLoS One 2017; 12:e0180401. [PMID: 28753604 PMCID: PMC5533340 DOI: 10.1371/journal.pone.0180401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 06/15/2017] [Indexed: 11/23/2022] Open
Abstract
Treatment with tyrosine kinase inhibitors is the standard of care for Philadelphia chromosome positive leukemias. However the eradication of leukemia initiating cells remains a challenge. Circumstantial evidence suggests that the cytokine microenvironment may play a role in BCR-ABL mediated leukemogenesis and in imatinib resistance. Gene expression analyses of BCR-ABL positive ALL long-term cultured cells revealed strong reduction of SOCS mRNA expression after imatinib treatment, thereby demonstrating a strong inhibition of cytokine signaling. In this study we employed SOCS1—a strong inhibitor of cytokine signaling—as a tool to terminate external cytokine signals in BCR-ABL transformed cells in vitro and in vivo. In colony formation assays with primary bone marrow cells, expression of SOCS1 decreased colony numbers under pro-proliferative cytokines, while it conferred growth resistance to anti-proliferative cytokines. Importantly, co-expression of SOCS1 with BCR-ABL led to the development of a MPD phenotype with a prolonged disease latency compared to BCR-ABL alone in a murine bone marrow transplantation model. Interestingly, SOCS1 co-expression protected 20% of mice from MPD development. In summary, we conclude that under pro-proliferative cytokine stimulation at the onset of myeloproliferative diseases SOCS1 acts as a tumor suppressor, while under anti-proliferative conditions it exerts oncogenic function. Therefore SOCS1 can promote opposing functions depending on the cytokine environment.
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Affiliation(s)
- Özlem Demirel
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Olivier Balló
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
| | - Pavankumar N. G. Reddy
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
- Hematology/Oncology, Children’s Hospital Boston, Harvard Medical School, Boston, United States of America
| | - Olesya Vakhrusheva
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
| | - Jing Zhang
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Astrid Eichler
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
| | - Ramona Fernandes
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
| | - Susanne Badura
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
| | - Hubert Serve
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Christian Brandts
- Department of Medicine, Hematology/Oncology, Goethe University, Frankfurt, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
- * E-mail:
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12
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The Philadelphia chromosome in leukemogenesis. CHINESE JOURNAL OF CANCER 2016; 35:48. [PMID: 27233483 PMCID: PMC4896164 DOI: 10.1186/s40880-016-0108-0] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 05/03/2016] [Indexed: 02/07/2023]
Abstract
The truncated chromosome 22 that results from the reciprocal translocation t(9;22)(q34;q11) is known as the Philadelphia chromosome (Ph) and is a hallmark of chronic myeloid leukemia (CML). In leukemia cells, Ph not only impairs the physiological signaling pathways but also disrupts genomic stability. This aberrant fusion gene encodes the breakpoint cluster region-proto-oncogene tyrosine-protein kinase (BCR-ABL1) oncogenic protein with persistently enhanced tyrosine kinase activity. The kinase activity is responsible for maintaining proliferation, inhibiting differentiation, and conferring resistance to cell death. During the progression of CML from the chronic phase to the accelerated phase and then to the blast phase, the expression patterns of different BCR-ABL1 transcripts vary. Each BCR-ABL1 transcript is present in a distinct leukemia phenotype, which predicts both response to therapy and clinical outcome. Besides CML, the Ph is found in acute lymphoblastic leukemia, acute myeloid leukemia, and mixed-phenotype acute leukemia. Here, we provide an overview of the clinical presentation and cellular biology of different phenotypes of Ph-positive leukemia and highlight key findings regarding leukemogenesis.
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13
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Haberbosch I, Rafiei A, Oancea C, Ottmann GO, Ruthardt M, Mian AA. BCR: a new target in resistance mediated by BCR/ABL-315I? Genes Cancer 2016; 7:36-46. [PMID: 27014420 PMCID: PMC4773704 DOI: 10.18632/genesandcancer.93] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Targeting BCR/ABL with Tyrosine kinase inhibitors (TKIs) is a proven concept for the treatment of Philadelphia chromosome-positive (Ph+) leukemias but the “gatekeeper” mutation T315I confers resistance against all approved TKIs, with the only exception of ponatinib, a multi-targeted kinase inhibitor. Besides resistance to TKIs, T315I also confers additional features to the leukemogenic potential of BCR/ABL, involving endogenous BCR. Therefore we studied the role of BCR on BCR/ABL mutants lacking functional domains indispensable for the oncogenic activity of BCR/ABL. We used the factor independent growth of murine myeloid progenitor 32D cells and the transformation of Rat-1 fibroblasts both mediated by BCR/ABL. Here we report that T315I restores the capacity to mediate factor-independent growth and transformation potential of loss-of-function mutants of BCR/ABL. Targeting endogenous Bcr abrogated the capacity of oligomerization deficient mutant of BCR/ABL-T315I to mediate factor independent growth of 32D cells and strongly reduced their transformation potential in Rat-1 cells, as well as led to the up-regulation of mitogen activated protein kinase (MAPK) pathway. Our data show that the T315I restores the capacity of loss-of-function mutants to transform cells which is dependent on the transphosphorylation of endogenous Bcr, which becomes a putative therapeutic target to overcome resistance by T315I.
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Affiliation(s)
| | - Anahita Rafiei
- Department of Hematology, University of Zurich, Zurich, Switzerland
| | - Claudia Oancea
- Deparment of Haematology, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Gerhart Oliver Ottmann
- Deparment of Haematology, School of Medicine, Cardiff University, Cardiff, United Kingdom; Cardiff Experimental Cancer Medicine Centre (ECMC), Cardiff, United Kingdom
| | - Martin Ruthardt
- Deparment of Haematology, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Afsar Ali Mian
- Deparment of Haematology, School of Medicine, Cardiff University, Cardiff, United Kingdom
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Paratala BS, Dolfi SC, Khiabanian H, Rodriguez-Rodriguez L, Ganesan S, Hirshfield KM. Emerging Role of Genomic Rearrangements in Breast Cancer: Applying Knowledge from Other Cancers. BIOMARKERS IN CANCER 2016; 8:1-14. [PMID: 26917980 PMCID: PMC4756769 DOI: 10.4137/bic.s34417] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 12/28/2015] [Accepted: 12/31/2015] [Indexed: 12/16/2022]
Abstract
Significant advances in our knowledge of cancer genomes are rapidly changing the way we think about tumor biology and the heterogeneity of cancer. Recent successes in genomically-guided treatment approaches accompanied by more sophisticated sequencing techniques have paved the way for deeper investigation into the landscape of genomic rearrangements in cancer. While considerable research on solid tumors has focused on point mutations that directly alter the coding sequence of key genes, far less is known about the role of somatic rearrangements. With many recurring alterations observed across tumor types, there is an obvious need for functional characterization of these genomic biomarkers in order to understand their relevance to tumor biology, therapy, and prognosis. As personalized therapy approaches are turning toward genomic alterations for answers, these biomarkers will become increasingly relevant to the practice of precision medicine. This review discusses the emerging role of genomic rearrangements in breast cancer, with a particular focus on fusion genes. In addition, it raises several key questions on the therapeutic value of such rearrangements and provides a framework to evaluate their significance as predictive and prognostic biomarkers.
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Affiliation(s)
- Bhavna S. Paratala
- Department of Medicine, Division of Medical Oncology, Rutgers Cancer Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
- Department of Cellular and Molecular Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Sonia C. Dolfi
- Department of Medicine, Division of Medical Oncology, Rutgers Cancer Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Hossein Khiabanian
- Department of Pathology, Division of Medical Informatics, Rutgers Cancer Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Lorna Rodriguez-Rodriguez
- Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Rutgers Cancer Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Shridar Ganesan
- Department of Medicine, Division of Medical Oncology, Rutgers Cancer Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Kim M. Hirshfield
- Department of Medicine, Division of Medical Oncology, Rutgers Cancer Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
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15
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Bruno BJ, Lim CS. Inhibition of Bcr-Abl in Human Leukemic Cells with a Coiled-Coil Protein Delivered by a Leukemia-Specific Cell-Penetrating Peptide. Mol Pharm 2015; 12:1412-21. [DOI: 10.1021/mp500701u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Benjamin J. Bruno
- Department
of Pharmaceutics
and Pharmaceutical Chemistry, College of Pharmacy, University of Utah, Salt Lake
City, Utah 84112, United States
| | - Carol S. Lim
- Department
of Pharmaceutics
and Pharmaceutical Chemistry, College of Pharmacy, University of Utah, Salt Lake
City, Utah 84112, United States
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16
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Woessner DW, Eiring AM, Bruno BJ, Zabriskie MS, Reynolds KR, Miller GD, O'Hare T, Deininger MW, Lim CS. A coiled-coil mimetic intercepts BCR-ABL1 dimerization in native and kinase-mutant chronic myeloid leukemia. Leukemia 2015; 29:1668-75. [PMID: 25721898 PMCID: PMC4621806 DOI: 10.1038/leu.2015.53] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/05/2015] [Accepted: 01/09/2015] [Indexed: 01/14/2023]
Abstract
Targeted therapy of chronic myeloid leukemia is currently based on small-molecule inhibitors that directly bind the tyrosine kinase domain of BCR-ABL1. This strategy has generally been successful, but is subject to drug resistance due to point mutations in the kinase domain. Kinase activity requires transactivation of BCR-ABL1 following an oligomerization event, which is mediated by the coiled-coil (CC) domain at the N-terminus of the protein. Here, we describe a rationally engineered mutant version of the CC domain, called CCmut3, which interferes with BCR-ABL1 oligomerization and promotes apoptosis in BCR-ABL1-expressing cells, regardless of kinase domain mutation status. CCmut3 exhibits strong pro-apoptotic and anti-proliferative activity in cell lines expressing native BCR-ABL1, single kinase domain mutant BCR-ABL1 (E255V and T315I) or compound mutant BCR-ABL1 (E255V/T315I). Moreover, CCmut3 inhibits colony formation by primary CML CD34+ cells ex vivo, including a sample expressing the T315I mutant. These data suggest that targeting BCR-ABL1 with CC mutants may provide a novel alternative strategy for treating patients with resistance to current targeted therapies.
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Affiliation(s)
- D W Woessner
- Department of Pharmacology and Toxicology, College of Pharmacy, The University of Utah, Salt Lake City, UT, USA
| | - A M Eiring
- Huntsman Cancer Institute, The University of Utah, Salt Lake City, UT, USA
| | - B J Bruno
- Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The University of Utah, Salt Lake City, UT, USA
| | - M S Zabriskie
- Huntsman Cancer Institute, The University of Utah, Salt Lake City, UT, USA
| | - K R Reynolds
- Huntsman Cancer Institute, The University of Utah, Salt Lake City, UT, USA
| | - G D Miller
- Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The University of Utah, Salt Lake City, UT, USA
| | - T O'Hare
- 1] Huntsman Cancer Institute, The University of Utah, Salt Lake City, UT, USA [2] Division of Hematology and Hematologic Malignancies, The University of Utah, Salt Lake City, UT, USA
| | - M W Deininger
- 1] Huntsman Cancer Institute, The University of Utah, Salt Lake City, UT, USA [2] Division of Hematology and Hematologic Malignancies, The University of Utah, Salt Lake City, UT, USA
| | - C S Lim
- 1] Huntsman Cancer Institute, The University of Utah, Salt Lake City, UT, USA [2] Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The University of Utah, Salt Lake City, UT, USA
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17
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T-cell receptor transfer into human T cells with ecotropic retroviral vectors. Gene Ther 2014; 21:533-8. [DOI: 10.1038/gt.2014.25] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/27/2014] [Accepted: 02/10/2014] [Indexed: 12/17/2022]
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18
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Bernt KM, Hunger SP. Current concepts in pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia. Front Oncol 2014; 4:54. [PMID: 24724051 PMCID: PMC3971203 DOI: 10.3389/fonc.2014.00054] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/06/2014] [Indexed: 12/22/2022] Open
Abstract
The t(9;22)(q34;q11) or Philadelphia chromosome creates a BCR-ABL1 fusion gene encoding for a chimeric BCR-ABL1 protein. It is present in 3-4% of pediatric acute lymphoblastic leukemia (Ph(+) ALL), and about 25% of adult ALL cases. Prior to the advent of tyrosine kinase inhibitors (TKI), Ph(+) ALL was associated with a very poor prognosis despite the use of intensive chemotherapy and frequently hematopoietic stem-cell transplantation (HSCT) in first remission. The development of TKIs revolutionized the therapy of Ph(+) ALL. Addition of the first generation ABL1 class TKI imatinib to intensive chemotherapy dramatically increased the survival for children with Ph(+) ALL and established that many patients can be cured without HSCT. In parallel, the mechanistic understanding of Ph(+) ALL expanded exponentially through careful mapping of pathways downstream of BCR-ABL1, the discovery of mutations in master regulators of B-cell development such as IKZF1 (Ikaros), PAX5, and early B-cell factor (EBF), the recognition of the complex clonal architecture of Ph(+) ALL, and the delineation of genomic, epigenetic, and signaling abnormalities contributing to relapse and resistance. Still, many important basic and clinical questions remain unanswered. Current clinical trials are testing second generation TKIs in patients with newly diagnosed Ph(+) ALL. Neither the optimal duration of therapy nor the optimal chemotherapy backbone are currently defined. The role of HSCT in first remission and post-transplant TKI therapy also require further study. In addition, it will be crucial to continue to dig deeper into understanding Ph(+) ALL at a mechanistic level, and translate findings into complementary targeted approaches. Expanding targeted therapies hold great promise to decrease toxicity and improve survival in this high-risk disease, which provides a paradigm for how targeted therapies can be incorporated into treatment of other high-risk leukemias.
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Affiliation(s)
- Kathrin M Bernt
- Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado , Aurora, CO , USA
| | - Stephen P Hunger
- Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado , Aurora, CO , USA
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19
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Wang HX, Xiao H, Zhong L, Tao K, Li YJ, Huang SF, Wen JP, Feng WL. Cell-penetrating fusion peptides OD1 and OD2 interact with Bcr-Abl and influence the growth and apoptosis of K562 cells. Mol Cell Biochem 2013; 385:311-8. [PMID: 24091918 DOI: 10.1007/s11010-013-1841-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/26/2013] [Indexed: 11/26/2022]
Abstract
The Bcr-Abl oncoprotein is the cause of chronic myelogenous leukemia (CML). Crystal structure analysis suggests that Bcr30-63 is the core of the Bcr-Abl oligomerization interface for aberrant kinase activity; however, the precise role of other residues of Bcr1-72 excluding Bcr30-63 have not been evaluated. In this study, Bcr30-63 was named OD2 and other residues of Bcr1-72 were named OD1. Cytoplasmic transduction peptide (CTP) was used to carry molecules into cytoplasm. CTP-OD1 and CTP-OD2 fusion peptides were expressed from a cold-inducible expression system. Our results demonstrated that both fusion peptides could localize into the cytoplasm, specifically interact with the Bcr-Abl protein and further inhibit growth, induce apoptosis, and decrease the phosphorylation of Bcr-Abl in K562 cell lines. However, the viability of THP-1, a Bcr-Abl negative cell line, was unaffected. These results suggested that CTP-OD1 and CTP-OD2 may be an attractive therapeutic option to inhibit the activation of Bcr-Abl kinase in CML.
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Affiliation(s)
- Hai-Xia Wang
- Key Laboratory of Laboratory Medical Diagnostics Designated by the Ministry of Education, Department of Clinical Hematology, Chongqing Medical University, Chongqing, 400016, People's Republic of China
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20
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Najajreh Y, Khamaisie H, Ruimi N, Khatib S, Katzhendler J, Ruthardt M, Mahajna J. Oleylamine-carbonyl-valinol inhibits auto-phosphorylation activity of native and T315I mutated Bcr-Abl, and exhibits selectivity towards oncogenic Bcr-Abl in SupB15 ALL cell lines. Mol Biol Rep 2012; 40:2205-13. [PMID: 23212614 DOI: 10.1007/s11033-012-2282-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Accepted: 11/19/2012] [Indexed: 02/03/2023]
Abstract
Chronic myeloid leukemia (CML) is characterized by the presence of p210(Bcr-Abl) which exhibits an abnormal kinase activity. Selective Abl kinase inhibitors have been successfully established for the treatment of CML. Despite high rates of clinical response, CML patients can develop resistance against these kinase inhibitors mainly due to point mutations within the Abl protein kinase domain. Previously, we have identified oleic acid as the active component in the mushroom Daedalea gibbosa that inhibited the kinase activity of Bcr-Abl. Here, we report that the oleyl amine derivatives, S-1-(1-Hydroxymethyl-2-methyl-propyl)-3-octadec-9-enyl-urea [oleylaminocarbonyl-L-N-valinol,oroleylaminocarbonyl-S-2-isopropyl-N-ethanolamine,oleylamine-carbonyl-L-valinol] (cpd 6) and R-1-(1-Hydroxymethyl-2-methyl-propyl)-3-octadec-9-enyl-urea [oleylamineocarbonyl-D-N-valinol, oleylaminocarbonyl-R-2-isopropyl-N-ethanolamine, or oleylamine-carbonyl-D-valinol] (cpd 7), inhibited the activity of the native and T315I mutated Bcr-Abl. Furthermore, cpd 6 and 7 exhibited higher activity towards the oncogenic Bcr-Abl in comparison to native c-Abl in SupB15 Ph-positive ALL cell line.
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Affiliation(s)
- Yousef Najajreh
- Anticancer Drugs Research Lab, Faculty of Pharmacy, Al-Quds University, Jerusalem-Abu Dies, P.O. Box 20002, Palestine
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21
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Mian AA, Metodieva A, Badura S, Khateb M, Ruimi N, Najajreh Y, Ottmann OG, Mahajna J, Ruthardt M. Allosteric inhibition enhances the efficacy of ABL kinase inhibitors to target unmutated BCR-ABL and BCR-ABL-T315I. BMC Cancer 2012; 12:411. [PMID: 22985168 PMCID: PMC3488316 DOI: 10.1186/1471-2407-12-411] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 08/31/2012] [Indexed: 11/28/2022] Open
Abstract
Background Chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive (Ph+) acute lymphatic leukemia (Ph + ALL) are caused by the t(9;22), which fuses BCR to ABL resulting in deregulated ABL-tyrosine kinase activity. The constitutively activated BCR/ABL-kinase “escapes” the auto-inhibition mechanisms of c-ABL, such as allosteric inhibition. The ABL-kinase inhibitors (AKIs) Imatinib, Nilotinib or Dasatinib, which target the ATP-binding site, are effective in Ph + leukemia. Another molecular therapy approach targeting BCR/ABL restores allosteric inhibition. Given the fact that all AKIs fail to inhibit BCR/ABL harboring the ‘gatekeeper’ mutation T315I, we investigated the effects of AKIs in combination with the allosteric inhibitor GNF2 in Ph + leukemia. Methods The efficacy of this approach on the leukemogenic potential of BCR/ABL was studied in Ba/F3 cells, primary murine bone marrow cells, and untransformed Rat-1 fibroblasts expressing BCR/ABL or BCR/ABL-T315I as well as in patient-derived long-term cultures (PDLTC) from Ph + ALL-patients. Results Here, we show that GNF-2 increased the effects of AKIs on unmutated BCR/ABL. Interestingly, the combination of Dasatinib and GNF-2 overcame resistance of BCR/ABL-T315I in all models used in a synergistic manner. Conclusions Our observations establish a new approach for the molecular targeting of BCR/ABL and its resistant mutants using a combination of AKIs and allosteric inhibitors.
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Affiliation(s)
- Afsar Ali Mian
- Department of Hematology, Goethe University, Frankfurt, Germany
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22
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TAT-CC fusion protein depresses the oncogenicity of BCR-ABL in vitro and in vivo through interrupting its oligomerization. Amino Acids 2012; 44:461-72. [PMID: 22782217 DOI: 10.1007/s00726-012-1354-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 06/26/2012] [Indexed: 10/28/2022]
Abstract
Chronic myeloid leukemia (CML) is a clonal hematologic malignancy characterized by the BCR-ABL protein. BCR-ABL is a constitutively active tyrosine kinase and plays a critical role in the pathogenesis of CML. Imatinib mesylate, a selective tyrosine kinase inhibitor, is effective in CML, but drug resistance and relapse occur. The coiled-coil (CC) domain located in BCR(1-72) mediates BCR-ABL tetramerization, which is essential for the activation of tyrosine kinase and transformation potential of BCR-ABL. CC domain is supposed to be a therapeutic target for CML. We purified a TAT-CC protein competively binding with the endogenous CC domain to reduce BCR-ABL kinase activity. We found that TAT-CC co-located and interacted with BCR-ABL in Ba/F3-p210 and K562 cells. It induced apoptosis and inhibited proliferation in these cells. It increased the sensitivity of these cells to imatinib and reduced the phosphorylation of BCR-ABL, CRKL and STAT5. We confirmed that TAT-CC could attenuate the oncogenicity of Ba/F3-p210 cells and diminish the volume of K562 solid tumor in mice. We conclude targeting the CC may provide a complementary therapy to inhibit BCR-ABL oncogenicity.
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Abstract
Abl kinases are prototypic cytoplasmic tyrosine kinases and are involved in a variety of chromosomal aberrations in different cancers. This causes the expression of Abl fusion proteins, such as Bcr-Abl, that are constitutively activated and drivers of tumorigenesis. Over the past decades, biochemical and functional studies on the molecular mechanisms of Abl regulation have gone hand in hand with progression of our structural understanding of autoinhibited and active Abl conformations. In parallel, Abl oncoproteins have become prime molecular targets for cancer therapy, using adenosine triphosphate (ATP)-competitive kinase inhibitors, such as imatinib. Abl-targeting drugs serve as a paradigm for our understanding of kinase inhibitor action, specificity, and resistance development. In this review article, I will review the molecular mechanisms that are responsible for the regulation of Abl kinase activity and how oncogenic Abl fusions signal. Furthermore, past and ongoing efforts to target Abl oncoproteins using ATP-competitive and allosteric inhibitors, as well as future possibilities using combination therapy, will be discussed.
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Affiliation(s)
- Oliver Hantschel
- École polytechnique fédérale de Lausanne (EPFL), School of Life Sciences, Swiss Institute for Experimental Cancer Research (ISREC), Lausanne, Switzerland
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24
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Dixon AS, Miller GD, Bruno BJ, Constance JE, Woessner DW, Fidler TP, Robertson JC, Cheatham TE, Lim CS. Improved coiled-coil design enhances interaction with Bcr-Abl and induces apoptosis. Mol Pharm 2011; 9:187-95. [PMID: 22136227 DOI: 10.1021/mp200461s] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The oncoprotein Bcr-Abl drives aberrant downstream activity through trans-autophosphorylation of homo-oligomers in chronic myelogenous leukemia (CML).(1, 2) The formation of Bcr-Abl oligomers is achieved through the coiled-coil domain at the N-terminus of Bcr.(3, 4) We have previously reported a modified version of this coiled-coil domain, CCmut2, which exhibits disruption of Bcr-Abl oligomeric complexes and results in decreased proliferation of CML cells and induction of apoptosis.(5) A major contributing factor to these enhanced capabilities is the destabilization of the CCmut2 homodimers, increasing the availability to interact with and inhibit Bcr-Abl. Here, we included an additional mutation (K39E) that could in turn further destabilize the mutant homodimer. Incorporation of this modification into CCmut2 (C38A, S41R, L45D, E48R, Q60E) generated what we termed CCmut3, and resulted in further improvements in the binding properties with the wild-type coiled-coil domain representative of Bcr-Abl [corrected]. A separate construct containing one revert mutation, CCmut4, did not demonstrate improved oligomeric properties and indicated the importance of the L45D mutation. CCmut3 demonstrated improved oligomerization via a two-hybrid assay as well as through colocalization studies, in addition to showing similar biologic activity as CCmut2. The improved binding between CCmut3 and the Bcr-Abl coiled-coil may be used to redirect Bcr-Abl to alternative subcellular locations with interesting therapeutic implications.
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Affiliation(s)
- Andrew S Dixon
- Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108, United States
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25
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Direct interaction of PU.1 with oncogenic transcription factors reduces its serine phosphorylation and promoter binding. Leukemia 2011; 26:1338-47. [DOI: 10.1038/leu.2011.331] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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26
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Mian AA, Metodieva A, Najajreh Y, Ottmann OG, Mahajna J, Ruthardt M. p185(BCR/ABL) has a lower sensitivity than p210(BCR/ABL) to the allosteric inhibitor GNF-2 in Philadelphia chromosome-positive acute lymphatic leukemia. Haematologica 2011; 97:251-7. [PMID: 22058195 DOI: 10.3324/haematol.2011.047191] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND The t(9;22) translocation leads to the formation of the chimeric breakpoint cluster region/c-abl oncogene 1 (BCR/ABL) fusion gene on der22, the Philadelphia chromosome. The p185(BCR/ABL) or the p210(BCR/ABL) fusion proteins are encoded as a result of the translocation, depending on whether a "minor" or "major" breakpoint occurs, respectively. Both p185(BCR/ABL) and p210(BCR/ABL) exhibit constitutively activated ABL kinase activity. Through fusion to BCR the ABL kinase in p185(BCR/ABL) and p210(BCR/ABL) "escapes" the auto-inhibition mechanisms of c-ABL, such as allosteric inhibition. A novel class of compounds including GNF-2 restores allosteric inhibition of the kinase activity and the transformation potential of BCR/ABL. Here we investigated whether there are differences between p185(BCR/ABL) and p210(BCR/ABL) regarding their sensitivity towards allosteric inhibition by GNF-2 in models of Philadelphia chromosome-positive acute lymphatic leukemia. DESIGN AND METHODS We investigated the anti-proliferative activity of GNF-2 in different Philadelphia chromosome-positive acute lymphatic leukemia models, such as cell lines, patient-derived long-term cultures and factor-dependent lymphatic Ba/F3 cells expressing either p185(BCR/ABL) or p210(BCR/ABL) and their resistance mutants. RESULTS The inhibitory effects of GNF-2 differed constantly between p185(BCR/ABL) and p210(BCR/ABL) expressing cells. In all three Philadelphia chromosome-positive acute lymphatic leukemia models, p210(BCR/ABL)-transformed cells were more sensitive to GNF-2 than were p185BCR/ABL-positive cells. Similar results were obtained for p185(BCR/ABL) and the p210(BCR/ABL) harboring resistance mutations. CONCLUSIONS Our data provide the first evidence of a differential response of p185(BCR/ABL)- and p210(BCR/ABL)- transformed cells to allosteric inhibition by GNF-2, which is of importance for the treatment of patients with Philadelphia chromosome-positive acute lymphatic leukemia.
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Affiliation(s)
- Afsar A Mian
- Department of Hematology, Goethe University, Frankfurt, Germany.
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Dixon AS, Pendley SS, Bruno BJ, Woessner DW, Shimpi AA, Cheatham TE, Lim CS. Disruption of Bcr-Abl coiled coil oligomerization by design. J Biol Chem 2011; 286:27751-60. [PMID: 21659527 DOI: 10.1074/jbc.m111.264903] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Oligomerization is an important regulatory mechanism for many proteins, including oncoproteins and other pathogenic proteins. The oncoprotein Bcr-Abl relies on oligomerization via its coiled coil domain for its kinase activity, suggesting that a designed coiled coil domain with enhanced binding to Bcr-Abl and reduced self-oligomerization would be therapeutically useful. Key mutations in the coiled coil domain of Bcr-Abl were identified that reduce homo-oligomerization through intermolecular charge-charge repulsion yet increase interaction with the Bcr-Abl coiled coil through additional salt bridges, resulting in an enhanced ability to disrupt the oligomeric state of Bcr-Abl. The mutations were modeled computationally to optimize the design. Assays performed in vitro confirmed the validity and functionality of the optimal mutations, which were found to exhibit reduced homo-oligomerization and increased binding to the Bcr-Abl coiled coil domain. Introduction of the mutant coiled coil into K562 cells resulted in decreased phosphorylation of Bcr-Abl, reduced cell proliferation, and increased caspase-3/7 activity and DNA segmentation. Importantly, the mutant coiled coil domain was more efficacious than the wild type in all experiments performed. The improved inhibition of Bcr-Abl through oligomeric disruption resulting from this modified coiled coil domain represents a viable alternative to small molecule inhibitors for therapeutic intervention.
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Affiliation(s)
- Andrew S Dixon
- Department of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, University of Utah, Salt Lake City, Utah 84108, USA
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28
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Oancea C, Rüster B, Henschler R, Puccetti E, Ruthardt M. The t(6;9) associated DEK/CAN fusion protein targets a population of long-term repopulating hematopoietic stem cells for leukemogenic transformation. Leukemia 2010; 24:1910-9. [PMID: 20827285 DOI: 10.1038/leu.2010.180] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The t(6;9)-positive acute myeloid leukemia (AML) is classified as a separate clinical entity because of its early onset and poor prognosis. The hallmark of t(6;9) AML is the expression of the DEK/CAN fusion protein. The leukemogenic potential of DEK/CAN has been called into question, because it was shown to be unable to block the differentiation of hematopoietic progenitors. We found that DEK/CAN initiated leukemia from a small subpopulation within the hematopoietic stem cell (HSC) population expressing a surface marker pattern of long-term (LT) HSC. The propagation of established DEK/CAN-positive leukemia was not restricted to the LT-HSC population, but occurred even from more mature and heterogeneous cell populations. This finding indicates that in DEK/CAN-induced leukemia, there is a difference between 'leukemia-initiating cells' (L-ICs) and 'leukemia-maintaining cells' (L-MCs). In contrast to the L-IC cells represented by a very rare subpopulation of LT-HSC, the L-MC seem to be represented by a larger and phenotypically heterogeneous cell population.
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Affiliation(s)
- C Oancea
- Department of Hematology, Goethe University, Frankfurt, Germany
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Dixon AS, Lim CS. The nuclear translocation assay for intracellular protein-protein interactions and its application to the Bcr coiled-coil domain. Biotechniques 2010; 49:519-24. [PMID: 20615205 PMCID: PMC2949290 DOI: 10.2144/000113452] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Protein interactions are critical for normal biological processes and molecular pathogenesis. While it is important to study these interactions, there are limited assays that are performed inside the cell, in the native cell environment, where the majority of protein-protein interactions take place. Here we present a method of studying protein interactions intracellularly using one protein of interest fused to a localization-controllable enhanced GFP (EGFP) construct and the other protein of interest fused to the red fluorescent protein, DsRed. Nuclear translocation of the EGFP construct is induced by addition of a ligand, and the difference in nuclear localization between the induced and noninduced states of the DsRed construct provides an indication of the interaction between the two proteins. This assay, the nuclear translocation assay (NTA), is introduced here as broadly applicable for studying protein interactions in the native environment inside cells and is demonstrated using forms of the coiled-coil domain from the breakpoint cluster region (Bcr) protein.
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Affiliation(s)
- Andrew S Dixon
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, 84108, USA
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Zheng X, Oancea C, Henschler R, Moore MAS, Ruthardt M. Reciprocal t(9;22) ABL/BCR fusion proteins: leukemogenic potential and effects on B cell commitment. PLoS One 2009; 4:e7661. [PMID: 19876398 PMCID: PMC2764858 DOI: 10.1371/journal.pone.0007661] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 10/07/2009] [Indexed: 11/18/2022] Open
Abstract
Background t(9;22) is a balanced translocation, and the chromosome 22 breakpoints (Philadelphia chromosome – Ph+) determine formation of different fusion genes that are associated with either Ph+ acute lymphatic leukemia (Ph+ ALL) or chronic myeloid leukemia (CML). The “minor” breakpoint in Ph+ ALL encodes p185BCR/ABL from der22 and p96ABL/BCR from der9. The “major” breakpoint in CML encodes p210BCR/ABL and p40ABL/BCR. Herein, we investigated the leukemogenic potential of the der9-associated p96ABL/BCR and p40ABL/BCR fusion proteins and their roles in the lineage commitment of hematopoietic stem cells in comparison to BCR/ABL. Methodology All t(9;22) derived proteins were retrovirally expressed in murine hematopoietic stem cells (SL cells) and human umbilical cord blood cells (UCBC). Stem cell potential was determined by replating efficiency, colony forming - spleen and competitive repopulating assays. The leukemic potential of the ABL/BCR fusion proteins was assessed by in a transduction/transplantation model. Effects on the lineage commitment and differentiation were investigated by culturing the cells under conditions driving either myeloid or lymphoid commitment. Expression of key factors of the B-cell differentiation and components of the preB-cell receptor were determined by qRT-PCR. Principal Findings Both p96ABL/BCR and p40ABL/BCR increased proliferation of early progenitors and the short term stem cell capacity of SL-cells and exhibited own leukemogenic potential. Interestingly, BCR/ABL gave origin exclusively to a myeloid phenotype independently from the culture conditions whereas p96ABL/BCR and to a minor extent p40ABL/BCR forced the B-cell commitment of SL-cells and UCBC. Conclusions/Significance Our here presented data establish the reciprocal ABL/BCR fusion proteins as second oncogenes encoded by the t(9;22) in addition to BCR/ABL and suggest that ABL/BCR contribute to the determination of the leukemic phenotype through their influence on the lineage commitment.
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Affiliation(s)
- Xiaomin Zheng
- Department of Hematology, Laboratory for Tumor Stem Cell Biology, Goethe University, Frankfurt, Germany
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Claudia Oancea
- Department of Hematology, Laboratory for Tumor Stem Cell Biology, Goethe University, Frankfurt, Germany
| | - Reinhard Henschler
- Department of Transfusion Medicine and Immunohematology, Goethe University, Frankfurt, Germany
| | - Malcolm A. S. Moore
- Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Martin Ruthardt
- Department of Hematology, Laboratory for Tumor Stem Cell Biology, Goethe University, Frankfurt, Germany
- * E-mail:
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Oligomerization inhibition, combined with allosteric inhibition, abrogates the transformation potential of T315I-positive BCR/ABL. Leukemia 2009; 23:2242-7. [PMID: 19798092 DOI: 10.1038/leu.2009.194] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The t(9;22) translocation leads to the formation of the chimeric bcr/abl fusion gene, which encodes the BCR/ABL fusion protein. In contrast to its physiological counterpart c-ABL, the BCR/ABL kinase is constitutively activated, inducing the leukemic phenotype. The N-terminus of c-ABL (Cap region) contributes to the regulation of its kinase function. It is myristoylated, and the myristate residue binds to a hydrophobic pocket in the kinase domain known as the myristoyl-binding pocket in a process called 'capping', which results in an auto-inhibited conformation. Because the cap region is replaced by the N-terminus of BCR, the BCR/ABL 'escapes' this auto-inhibition. Allosteric inhibition by myristate 'mimics', such as GNF-2, is able to inhibit unmutated BCR/ABL, but not the BCR/ABL that harbors the 'gatekeeper' mutation T315I. In this study, we analyzed the possibility of increasing the efficacy of allosteric inhibition by blocking BCR/ABL oligomerization. We showed that inhibition of oligomerization was able to not only increase the efficacy of GNF-2 on unmutated BCR/ABL, but also overcome the resistance of BCR/ABL-T315I to allosteric inhibition. These results strongly suggest that the response to allosteric inhibition by GNF-2 is inversely related to the degree of oligomerization of BCR/ABL. In summary, our observations establish a new approach for the molecular targeting of BCR/ABL and its resistant mutants represented by the combination of oligomerization and allosteric inhibitors.
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Translocation Biosensors - Cellular System Integrators to Dissect CRM1-Dependent Nuclear Export by Chemicogenomics. SENSORS 2009; 9:5423-45. [PMID: 22346706 PMCID: PMC3274152 DOI: 10.3390/s90705423] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 07/03/2009] [Accepted: 07/03/2009] [Indexed: 12/20/2022]
Abstract
Fluorescent protein biosensors are powerful cellular systems biology tools for dissecting the complexity of cellular processes with high spatial and temporal resolution. As regulated nucleo-cytoplasmic transport is crucial for the modulation of numerous (patho)physiological cellular responses, a detailed understanding of its molecular mechanism would open up novel options for a rational manipulation of the cell. In contrast to genetic approaches, we here established and employed high-content cellular translocation biosensors applicable for dissecting nuclear export by chemicogenomics. A431 cell lines, stably expressing a translocation biosensor composed of glutathione S-transferase, GFP and a rational combination of nuclear import and export signals, were engineered by antibiotic selection and flow cytometry sorting. Using an optimized nuclear translocation algorithm, the translocation response could be robustly quantified on the Cellomics Arrayscan® VTI platform. Subsequent to assay optimization, the assay was developed into a higher density 384-well format high-content assay and employed for the screening of the 17K ChemBioNet compound collection. This library was selected on the basis of a genetic algorithm used to identify maximum common chemical substructures in a database of annotated bioactive molecules and hence, is well-placed in the chemical space covered by bioactive compounds. Automated multiparameter data analysis combined with visual inspection allowed us to identify and to rationally discriminate true export inhibitors from false positives, which included fluorescent compounds or cytotoxic substances that dramatically affected the cellular morphology. A total of 120 potential hit compounds were selected for Cellomics Arrayscan® VTI based rescreening. The export inhibitory activity of 20 compounds effective at concentrations < 25 μM were confirmed by fluorescence microscopy in several cell lines. Interestingly, kinetic analysis allowed the identification of inhibitors capable to interfere with the export receptor CRM1-mediated nuclear export not only in an irreversible, but also in a reversible fashion. In sum, exploitation of biosensor based screening allows the identification of chemicogenomic tools applicable for dissecting nucleo-cytoplasmic transport in living cells.
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The gatekeeper mutation T315I confers resistance against small molecules by increasing or restoring the ABL-kinase activity accompanied by aberrant transphosphorylation of endogenous BCR, even in loss-of-function mutants of BCR/ABL. Leukemia 2009; 23:1614-21. [PMID: 19369965 DOI: 10.1038/leu.2009.69] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In Philadelphia chromosome-positive (Ph+) leukemia BCR/ABL induces the leukemic phenotype. Targeted inhibition of BCR/ABL by kinase inhibitors leads to complete remission. However, patients with advanced Ph+ leukemia relapse and acquire resistance, mainly due to point mutations in BCR/ABL. The 'gatekeeper mutation' T315I is responsible for a general resistance to small molecules. It seems not only to decrease the affinity for kinase inhibitors, but to also confer additional features to the leukemogenic potential of BCR/ABL. To determine the role of T315I in resistance to the inhibition of oligomerization and in the leukemogenic potential of BCR/ABL, we investigated its influence on loss-of-function mutants with regard to the capacity to mediate factor independence. Here, we show that T315I (i) requires autophosphorylation at tyrosine 177 in the BCR-portion to mediate resistance against the inhibition of oligomerization; (ii) restores the capacity to mediate factor-independent growth of loss-of-function mutants due to an increase in or activation of ABL-kinase; (iii) leads to phosphorylation of endogenous BCR, suggesting aberrant substrate activation by BCR/ABL harboring the T315I mutation. These data show that T315I confers additional leukemogenic activity to BCR/ABL, which might explain the clinical behavior of patients with BCR/ABL-T315I-positive blasts.
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Gwanmesia PM, Romanski A, Schwarz K, Bacic B, Ruthardt M, Ottmann OG. The effect of the dual Src/Abl kinase inhibitor AZD0530 on Philadelphia positive leukaemia cell lines. BMC Cancer 2009; 9:53. [PMID: 19216789 PMCID: PMC2654659 DOI: 10.1186/1471-2407-9-53] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Accepted: 02/13/2009] [Indexed: 11/10/2022] Open
Abstract
Background Imatinib mesylate, a selective inhibitor of Abl tyrosine kinase, is efficacious in treating chronic myeloid leukaemia (CML) and Ph+ acute lymphoblastic leukaemia (ALL). However, most advanced-phase CML and Ph+ ALL patients relapse on Imatinib therapy. Several mechanisms of refractoriness have been reported, including the activation of the Src-family kinases (SFK). Here, we investigated the biological effect of the new specific dual Src/Abl kinase inhibitor AZD0530 on Ph+ leukaemic cells. Methods Cell lines used included BV173 (CML in myeloid blast crisis), SEM t(4;11), Ba/F3 (IL-3 dependent murine pro B), p185Bcr-Abl infected Ba/F3 cells, p185Bcr-Abl mutant infected Ba/F3 cells, SupB15 (Ph+ ALL) and Imatinib resistant SupB15 (RTSupB15) (Ph+ ALL) cells. Cells were exposed to AZD0530 and Imatinib. Cell proliferation, apoptosis, survival and signalling pathways were assessed by dye exclusion, flow cytometry and Western blotting respectively. Results AZD0530 specifically inhibited the growth of, and induced apoptosis in CML and Ph+ ALL cells in a dose dependent manner, but showed only marginal effects on Ph- ALL cells. Resistance to Imatinib due to the mutation Y253F in p185Bcr-Abl was overcome by AZD0530. Combination of AZD0530 and Imatinib showed an additive inhibitory effect on the proliferation of CML BV173 cells but not on Ph+ ALL SupB15 cells. An ongoing transphosphorylation was demonstrated between SFKs and Bcr-Abl. AZD0530 significantly down-regulated the activation of survival signalling pathways in Ph+ cells, resistant or sensitive to Imatinib, with the exception of the RTSupB15. Conclusion Our results indicate that AZD0530 targets both Src and Bcr-Abl kinase activity and reduces the leukaemic maintenance by Bcr-Abl.
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