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Tecik M, Adan A. Emerging DNA Methylome Targets in FLT3-ITD-Positive Acute Myeloid Leukemia: Combination Therapy with Clinically Approved FLT3 Inhibitors. Curr Treat Options Oncol 2024; 25:719-751. [PMID: 38696033 PMCID: PMC11222205 DOI: 10.1007/s11864-024-01202-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2024] [Indexed: 07/04/2024]
Abstract
OPINION STATEMENT The internal tandem duplication (ITD) mutation of the FMS-like receptor tyrosine kinase 3 (FLT3-ITD) is the most common mutation observed in approximately 30% of acute myeloid leukemia (AML) patients. It represents poor prognosis due to continuous activation of downstream growth-promoting signaling pathways such as STAT5 and PI3K/AKT. Hence, FLT3 is considered an attractive druggable target; selective small FLT3 inhibitors (FLT3Is), such as midostaurin and quizartinib, have been clinically approved. However, patients possess generally poor remission rates and acquired resistance when FLT3I used alone. Various factors in patients could cause these adverse effects including altered epigenetic regulation, causing mainly abnormal gene expression patterns. Epigenetic modifications are required for hematopoietic stem cell (HSC) self-renewal and differentiation; however, critical driver mutations have been identified in genes controlling DNA methylation (such as DNMT3A, TET2, IDH1/2). These regulators cause leukemia pathogenesis and affect disease diagnosis and prognosis when they co-occur with FLT3-ITD mutation. Therefore, understanding the role of different epigenetic alterations in FLT3-ITD AML pathogenesis and how they modulate FLT3I's activity is important to rationalize combinational treatment approaches including FLT3Is and modulators of methylation regulators or pathways. Data from ongoing pre-clinical and clinical studies will further precisely define the potential use of epigenetic therapy together with FLT3Is especially after characterized patients' mutational status in terms of FLT3 and DNA methlome regulators.
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Affiliation(s)
- Melisa Tecik
- Bioengineering Program, Graduate School of Engineering and Science, Abdullah Gul University, Kayseri, Turkey
| | - Aysun Adan
- Department of Molecular Biology and Genetics, Faculty of Life and Natural Sciences, Abdullah Gul University, Kayseri, Turkey.
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2
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Tecik M, Adan A. Therapeutic Targeting of FLT3 in Acute Myeloid Leukemia: Current Status and Novel Approaches. Onco Targets Ther 2022; 15:1449-1478. [PMID: 36474506 PMCID: PMC9719701 DOI: 10.2147/ott.s384293] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 11/19/2022] [Indexed: 08/13/2023] Open
Abstract
FMS-like tyrosine kinase 3 (FLT3) is mutated in approximately 30% of acute myeloid leukemia (AML) patients. The presence of FLT3-ITD (internal tandem duplication, 20-25%) mutation and, to a lesser extent, FLT3-TKD (tyrosine kinase domain, 5-10%) mutation is associated with poorer diagnosis and therapy response since the leukemic cells become hyperproliferative and resistant to apoptosis after continuous activation of FLT3 signaling. Targeting FLT3 has been the focus of many pre-clinical and clinical studies. Hence, many small-molecule FLT3 inhibitors (FLT3is) have been developed, some of which are approved such as midostaurin and gilteritinib to be used in different clinical settings, either in combination with chemotherapy or alone. However, many questions regarding the best treatment strategy remain to be answered. On the other hand, various FLT3-dependent and -independent resistance mechanisms could be evolved during FLT3i therapy which limit their clinical impact. Therefore, identifying molecular mechanisms of resistance and developing novel strategies to overcome this obstacle is a current interest in the field. In this review, recent studies of approved FLT3i and knowledge about major resistance mechanisms of clinically approved FLT3i's will be discussed together with novel treatment approaches such as designing novel FLT3i and dual FLT3i and combination strategies including approved FLT3i plus small-molecule agents targeting altered molecules in the resistant cells to abrogate resistance. Moreover, how to choose an appropriate FLT3i for the patients will be summarized based on what is currently known from available clinical data. In addition, strategies beyond FLT3i's including immunotherapeutics, small-molecule FLT3 degraders, and flavonoids will be summarized to highlight potential alternatives in FLT3-mutated AML therapy.
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Affiliation(s)
- Melisa Tecik
- Bioengineering Program, Graduate School of Engineering and Science, Abdullah Gul University, Kayseri, Turkey
| | - Aysun Adan
- Department of Molecular Biology and Genetics, Faculty of Life and Natural Sciences, Abdullah Gul University, Kayseri, Turkey
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3
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Ding L, Zhang Q, Zhao K, Jiao X, Zhou Y, Fan W, Tang C. Synthesis and biological evaluation of novel 5,6-dihydrobenzo[h]quinazoline derivatives as FLT3 inhibitors. Chem Biol Drug Des 2021; 99:527-534. [PMID: 34877799 DOI: 10.1111/cbdd.13992] [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: 09/05/2021] [Revised: 11/10/2021] [Accepted: 11/27/2021] [Indexed: 11/29/2022]
Abstract
Fms-like tyrosine kinase 3 (FLT3) is widely expressed and often mutated in acute myeloid leukemia (AML), which makes it an important target for the treatment of AML. The structure-based synthesis and biological evaluation of 5,6-dihydrobenzo[h]quinazoline derivatives as FLT3 inhibitors have been studied in this paper. III-1a, III-1c, III-2a, III-2c, and III-4a displayed comparable inhibitory potency against FLT3-ITD and showed remarkable antiproliferative activities against MV4-11.
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Affiliation(s)
- Lei Ding
- School of Pharmaceutical Science, Jiangnan University, Wuxi, China
| | - Qing Zhang
- School of Pharmaceutical Science, Jiangnan University, Wuxi, China
| | - Kuantao Zhao
- School of Pharmaceutical Science, Jiangnan University, Wuxi, China
| | - Xiaoyu Jiao
- School of Pharmaceutical Science, Jiangnan University, Wuxi, China
| | - Ying Zhou
- School of Pharmaceutical Science, Jiangnan University, Wuxi, China
| | - Weizheng Fan
- School of Pharmaceutical Science, Jiangnan University, Wuxi, China
| | - Chunlei Tang
- School of Pharmaceutical Science, Jiangnan University, Wuxi, China
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4
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Hu S, Liu J, Chen S, Gao J, Zhou Y, Liu T, Dong X. Discover Novel Covalent Inhibitors Targeting FLT3 through Hybrid Virtual Screening Strategy. Biol Pharm Bull 2021; 44:1872-1877. [PMID: 34853270 DOI: 10.1248/bpb.b21-00579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
FMS-like tyrosine kinase 3 (FLT3) plays a very important role in regulating the proliferation, differentiation and survival of normal hematopoietic stem cells. Internal tandem duplications of the FLT3 gene (FLT3-ITD) mutations are present in 25% of all acute myeloid leukemia (AML) patients and are frequently associated with adverse clinical outcomes. Therefore, FLT3-ITD is a promising target for the treatment of AML. The use of covalent virtual screenings has shown that efficient rational approaches for the rapid discovery of new drugs scaffold. Herein, we report a hybrid virtual screening strategy that led to the discovery of FLT3 inhibitors. Using the combination of non-covalent docking and covalent docking, 8 compounds were found to inhibit FLT3, and G856-8335, S346-0154 are also effective against mutant FLT3. These two compounds also show selectivity to receptor tyrosine kinase (C-KIT), which has the potential for optimization. And this work can be extended to the screening of other covalent inhibitors.
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Affiliation(s)
- Shengquan Hu
- Hangzhou Institute of Innovative Medicine, Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University
| | - Jing Liu
- Hangzhou Institute of Innovative Medicine, Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University
| | - Sikang Chen
- Hangzhou Institute of Innovative Medicine, Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University
| | - Jian Gao
- Hangzhou Institute of Innovative Medicine, Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University
| | - Yubo Zhou
- National Center for Drug Screening, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences
| | - Tao Liu
- Hangzhou Institute of Innovative Medicine, Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University
| | - Xiaowu Dong
- Hangzhou Institute of Innovative Medicine, Institute of Drug Discovery and Design, College of Pharmaceutical Sciences, Zhejiang University.,Cancer Center, Zhejiang University.,Innovation Institute for Artificial Intelligence in Medicine, Zhejiang University
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5
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Al-Subaie AM, Kamaraj B. The Structural Effect of FLT3 Mutations at 835th Position and Their Interaction with Acute Myeloid Leukemia Inhibitors: In Silico Approach. Int J Mol Sci 2021; 22:7602. [PMID: 34299222 PMCID: PMC8303888 DOI: 10.3390/ijms22147602] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 06/30/2021] [Accepted: 07/09/2021] [Indexed: 12/25/2022] Open
Abstract
FMS-like tyrosine kinase 3 (FLT3) gene mutations have been found in more than one-third of Acute Myeloid Leukemia (AML) cases. The most common point mutation in FLT3 occurs at the 835th residue (D835A/E/F/G/H/I/N/V/Y), in the activation loop region. The D835 residue is critical in maintaining FLT3 inactive conformation; these mutations might influence the interaction with clinically approved AML inhibitors used to treat the AML. The molecular mechanism of each of these mutations and their interactions with AML inhibitors at the atomic level is still unknown. In this manuscript, we have investigated the structural consequence of native and mutant FLT-3 proteins and their molecular mechanisms at the atomic level, using molecular dynamics simulations (MDS). In addition, we use the molecular docking method to investigate the binding pattern between the FLT-3 protein and AML inhibitors upon mutations. This study apparently elucidates that, due to mutations in the D835, the FLT-3 structure loses its conformation and becomes more flexible compared to the native FLT3 protein. These structural changes are suggested to contribute to the relapse and resistance responses to AML inhibitors. Identifying the effects of FLT3 at the molecular level will aid in developing a personalized therapeutic strategy for treating patients with FLT-3-associated AML.
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Affiliation(s)
- Abeer M. Al-Subaie
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Imam Abdulrahman Bin Faisal University, Dammam 31441, Saudi Arabia;
| | - Balu Kamaraj
- Department of Neuroscience Technology, College of Applied Medical Sciences in Jubail, Imam Abdulrahman Bin Faisal University, Jubail 35816, Saudi Arabia
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6
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FLT3 Tyrosine Kinase Inhibitors for the Treatment of Fit and Unfit Patients with FLT3-Mutated AML: A Systematic Review. Int J Mol Sci 2021; 22:ijms22115873. [PMID: 34070902 PMCID: PMC8198781 DOI: 10.3390/ijms22115873] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 11/17/2022] Open
Abstract
FLT3-mutated acute myeloid leukemia accounts for around 30% of acute myeloid leukemia (AML). The mutation carried a poor prognosis until the rise of tyrosine kinase inhibitors (TKIs). New potent and specific inhibitors have successfully altered the course of the disease, increasing the complete response rate and the survival of patients with FLT3-mutated AML. The aim of this article is to review all the current knowledge on these game-changing drugs as well as the unsolved issues raised by their use for fit and unfit FLT3-mutated AML patients. To this end, we analyzed the results of phase I, II, III clinical trials evaluating FLT3-TKI both in the first-line, relapse monotherapy or in combination referenced in the PubMed, the American Society of Hematology, the European Hematology Association, and the Clinicaltrials.gov databases, as well as basic science reports on TKI resistance from the same databases. The review follows a chronological presentation of the different trials that allowed the development of first- and second-generation TKI and ends with a review of the current lines of evidence on leukemic blasts resistance mechanisms that allow them to escape TKI.
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7
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Li M, Xue N, Liu X, Wang Q, Yan H, Liu Y, Wang L, Shi X, Cao D, Zhang K, Zhang Y. Discovery of Potent EGFR Inhibitors With 6-Arylureido-4-anilinoquinazoline Derivatives. Front Pharmacol 2021; 12:647591. [PMID: 34122069 PMCID: PMC8187944 DOI: 10.3389/fphar.2021.647591] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 05/06/2021] [Indexed: 12/22/2022] Open
Abstract
According to the classical pharmacophore fusion strategy, a series of 6-arylureido-4-anilinoquinazoline derivatives ( Compounds 7a - t ) were designed, synthesized, and biologically evaluated by the standard CCK-8 method and enzyme inhibition assay. Among the title compounds, Compounds 7a , 7c , 7d , 7f , 7i , 7o , 7p , and 7q exhibited promising anti-proliferative bioactivities, especially Compound 7i , which had excellent antitumor activity against the A549, HT-29, and MCF-7 cell lines (IC50 = 2.25, 1.72, and 2.81 μM, respectively) compared with gefitinib, erlotinib, and sorafenib. In addition, the enzyme activity inhibition assay indicated that the synthesized compounds had sub-micromolar inhibitory levels (IC50, 11.66-867.1 nM), which was consistent with the results of the tumor cell line growth inhibition tests. By comparing the binding mechanisms of Compound 7i (17.32 nM), gefitinib (25.42 nM), and erlotinib (33.25 nM) to the EGFR, it was found that Compound 7i could extend into the effective region with a similar action conformation to that of gefitinib and interact with residues L85, D86, and R127, increasing the binding affinity of Compound 7i to the EGFR. Based on the molecular hybridization strategy, 14 compounds with EGFR inhibitory activity were designed and synthesized, and the action mechanism was explored through computational approaches, providing valuable clues for the research of antitumor agents based on EGFR inhibitors.
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Affiliation(s)
- Meng Li
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
| | - Na Xue
- Department of Pharmaceutical Engineering, Hebei Chemical and Pharmaceutical College, Shijiazhuang, China
| | - Xingang Liu
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
| | - Qiaoyun Wang
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
| | - Hongyi Yan
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
| | - Yifan Liu
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
| | - Lei Wang
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
| | - Xiaowei Shi
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
| | - Deying Cao
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
| | - Kai Zhang
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
| | - Yang Zhang
- Department of Medicinal Chemistry, Hebei Medical University, Shijiazhuang, China
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8
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Abstract
Acute myeloid leukemia (AML) is a very heterogeneous type of blood cancer, which presents with a high rate of mortality especially in elderly patients. Better understanding of critical players, such as molecules with tumor suppressive properties, may help to fine-tune disease classification and thereby treatment modalities for this detrimental disease. Here, we summarize well-known and established tumor suppressors as well as emerging tumor suppressors, including transcription factors (TCFs) and other transcriptional regulators, such as epigenetic modulators. In addition, we look into the versatile field of miRNAs also interfering with tumorigenesis and progression, which offer new possibilities in AML diagnosis, prognosis, and therapy.
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Affiliation(s)
- Jacqueline Wallwitz
- Department Pharmacology, Physiology and Microbiology, Division Pharmacology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Petra Aigner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Dagmar Stoiber
- Department Pharmacology, Physiology and Microbiology, Division Pharmacology, Karl Landsteiner University of Health Sciences, Krems, Austria
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9
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Exploiting Clonal Evolution to Improve the Diagnosis and Treatment Efficacy Prediction in Pediatric AML. Cancers (Basel) 2021; 13:cancers13091995. [PMID: 33919131 PMCID: PMC8122278 DOI: 10.3390/cancers13091995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/12/2021] [Accepted: 04/19/2021] [Indexed: 01/18/2023] Open
Abstract
Despite improvements in therapeutic protocols and in risk stratification, acute myeloid leukemia (AML) remains the leading cause of childhood leukemic mortality. Indeed, the overall survival accounts for ~70% but still ~30% of pediatric patients experience relapse, with poor response to conventional chemotherapy. Thus, there is an urgent need to improve diagnosis and treatment efficacy prediction in the context of this disease. Nowadays, in the era of high throughput techniques, AML has emerged as an extremely heterogeneous disease from a genetic point of view. Different subclones characterized by specific molecular profiles display different degrees of susceptibility to conventional treatments. In this review, we describe in detail this genetic heterogeneity of pediatric AML and how it is linked to relapse in terms of clonal evolution. We highlight some innovative tools to characterize minor subclones that could help to enhance diagnosis and a preclinical model suitable for drugs screening. The final ambition of research is represented by targeted therapy, which could improve the prognosis of pediatric AML patients, as well as to limit the side toxicity of current treatments.
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10
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Pannecoucke E, Raes L, Savvides SN. Engineering and crystal structure of a monomeric FLT3 ligand variant. Acta Crystallogr F Struct Biol Commun 2021; 77:121-127. [PMID: 33830077 PMCID: PMC8034431 DOI: 10.1107/s2053230x21003289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/27/2021] [Indexed: 12/02/2022] Open
Abstract
The overarching paradigm for the activation of class III and V receptor tyrosine kinases (RTKs) prescribes cytokine-mediated dimerization of the receptor ectodomains and homotypic receptor-receptor interactions. However, structural studies have shown that the hematopoietic receptor FLT3, a class III RTK, does not appear to engage in such receptor-receptor contacts, despite its efficient dimerization by dimeric FLT3 ligand (FL). As part of efforts to better understand the intricacies of FLT3 activation, we sought to engineer a monomeric FL. It was found that a Leu27Asp substitution at the dimer interface of the cytokine led to a stable monomeric cytokine (FLL27D) without abrogation of receptor binding. The crystal structure of FLL27D at 1.65 Å resolution revealed that the introduced point mutation led to shielding of the hydrophobic footprint of the dimerization interface in wild-type FL without affecting the conformation of the FLT3 binding site. Thus, FLL27D can serve as a monomeric FL variant to further interrogate the assembly mechanism of extracellular complexes of FLT3 in physiology and disease.
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Affiliation(s)
- Erwin Pannecoucke
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 71, 9052 Zwijnaarde, Belgium
- Unit for Structural Biology, VIB Center for Inflammation Research, Technologiepark-Zwijnaarde 71, 9052 Zwijnaarde, Belgium
| | - Laurens Raes
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 71, 9052 Zwijnaarde, Belgium
- Laboratory for General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Gent, Belgium
| | - Savvas N. Savvides
- Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Technologiepark-Zwijnaarde 71, 9052 Zwijnaarde, Belgium
- Unit for Structural Biology, VIB Center for Inflammation Research, Technologiepark-Zwijnaarde 71, 9052 Zwijnaarde, Belgium
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11
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Sobanski T, Rose M, Suraweera A, O’Byrne K, Richard DJ, Bolderson E. Cell Metabolism and DNA Repair Pathways: Implications for Cancer Therapy. Front Cell Dev Biol 2021; 9:633305. [PMID: 33834022 PMCID: PMC8021863 DOI: 10.3389/fcell.2021.633305] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/19/2021] [Indexed: 12/13/2022] Open
Abstract
DNA repair and metabolic pathways are vital to maintain cellular homeostasis in normal human cells. Both of these pathways, however, undergo extensive changes during tumorigenesis, including modifications that promote rapid growth, genetic heterogeneity, and survival. While these two areas of research have remained relatively distinct, there is growing evidence that the pathways are interdependent and intrinsically linked. Therapeutic interventions that target metabolism or DNA repair systems have entered clinical practice in recent years, highlighting the potential of targeting these pathways in cancer. Further exploration of the links between metabolic and DNA repair pathways may open new therapeutic avenues in the future. Here, we discuss the dependence of DNA repair processes upon cellular metabolism; including the production of nucleotides required for repair, the necessity of metabolic pathways for the chromatin remodeling required for DNA repair, and the ways in which metabolism itself can induce and prevent DNA damage. We will also discuss the roles of metabolic proteins in DNA repair and, conversely, how DNA repair proteins can impact upon cell metabolism. Finally, we will discuss how further research may open therapeutic avenues in the treatment of cancer.
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Affiliation(s)
- Thais Sobanski
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Maddison Rose
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Amila Suraweera
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Kenneth O’Byrne
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
- Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Derek J. Richard
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Emma Bolderson
- Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
- Princess Alexandra Hospital, Brisbane, QLD, Australia
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12
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Long Y, Yu M, Ochnik AM, Karanjia JD, Basnet SK, Kebede AA, Kou L, Wang S. Discovery of novel 4-azaaryl-N-phenylpyrimidin-2-amine derivatives as potent and selective FLT3 inhibitors for acute myeloid leukaemia with FLT3 mutations. Eur J Med Chem 2021; 213:113215. [PMID: 33516985 DOI: 10.1016/j.ejmech.2021.113215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 01/15/2021] [Accepted: 01/15/2021] [Indexed: 01/12/2023]
Abstract
Feline McDonough sarcoma (FMS)-like tyrosine kinase 3 (FLT3) is one of the most pursued targets in the treatment of acute myeloid leukaemia (AML) as its gene amplification and mutations, particularly internal tandem duplication (ITD), contribute to the pathogenesis of AML and the resistance to known FLT3 inhibitors. To conquer this challenge, there is a quest for structurally novel FLT3 inhibitors. Herein, we report the discovery of a new series of 4-azaaryl-N-phenylpyrimidin-2-amine derivatives as potent and selective FLT3 inhibitors. Compounds 12b and 12r were capable of suppressing a wide range of mutated FLT3 kinases including ITD and D835Y mutants; the latter isoform is closely associated with acquired drug resistance. In addition, both compounds displayed an anti-proliferative specificity for FLT3-ITD-harbouring cell lines (i.e., MV4-11 and MOLM-13 cells) over those with expression of the wild-type kinase or even without FLT3 expression. In mechanistic studies using MV4-11 cells, 12b was found to diminish the phosphorylation of key downstream effectors of FLT3 and induce apoptosis, supporting an FLT3-ITD-targeted mechanism of its anti-proliferative action.
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Affiliation(s)
- Yi Long
- Drug Discovery and Development, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5001, Australia
| | - Mingfeng Yu
- Drug Discovery and Development, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5001, Australia
| | - Aleksandra M Ochnik
- Drug Discovery and Development, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5001, Australia
| | - Jasmine D Karanjia
- Drug Discovery and Development, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5001, Australia
| | - Sunita Kc Basnet
- Drug Discovery and Development, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5001, Australia
| | - Alemwork A Kebede
- Drug Discovery and Development, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5001, Australia
| | - Lianmeng Kou
- Drug Discovery and Development, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5001, Australia
| | - Shudong Wang
- Drug Discovery and Development, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5001, Australia.
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13
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Guruprasad P, Lee YG, Kim KH, Ruella M. The current landscape of single-cell transcriptomics for cancer immunotherapy. J Exp Med 2021; 218:e20201574. [PMID: 33601414 PMCID: PMC7754680 DOI: 10.1084/jem.20201574] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/28/2020] [Accepted: 12/02/2020] [Indexed: 12/28/2022] Open
Abstract
Immunotherapies such as immune checkpoint blockade and adoptive cell transfer have revolutionized cancer treatment, but further progress is hindered by our limited understanding of tumor resistance mechanisms. Emerging technologies now enable the study of tumors at the single-cell level, providing unprecedented high-resolution insights into the genetic makeup of the tumor microenvironment and immune system that bulk genomics cannot fully capture. Here, we highlight the recent key findings of the use of single-cell RNA sequencing to deconvolute heterogeneous tumors and immune populations during immunotherapy. Single-cell RNA sequencing has identified new crucial factors and cellular subpopulations that either promote tumor progression or leave tumors vulnerable to immunotherapy. We anticipate that the strategic use of single-cell analytics will promote the development of the next generation of successful, rationally designed immunotherapeutics.
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Affiliation(s)
- Puneeth Guruprasad
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Department of Medicine, Division of Hematology and Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Yong Gu Lee
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Department of Medicine, Division of Hematology and Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Ki Hyun Kim
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Department of Medicine, Division of Hematology and Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Marco Ruella
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Department of Medicine, Division of Hematology and Oncology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA
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14
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Gebru MT, Wang HG. Therapeutic targeting of FLT3 and associated drug resistance in acute myeloid leukemia. J Hematol Oncol 2020; 13:155. [PMID: 33213500 PMCID: PMC7678146 DOI: 10.1186/s13045-020-00992-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/03/2020] [Indexed: 02/07/2023] Open
Abstract
Acute myeloid leukemia (AML) is a heterogeneous disease caused by several gene mutations and cytogenetic abnormalities affecting differentiation and proliferation of myeloid lineage cells. FLT3 is a receptor tyrosine kinase commonly overexpressed or mutated, and its mutations are associated with poor prognosis in AML. Although aggressive chemotherapy often followed by hematopoietic stem cell transplant is the current standard of care, the recent approval of FLT3-targeted drugs is revolutionizing AML treatment that had remained unchanged since the 1970s. However, despite the dramatic clinical response to targeted agents, such as FLT3 inhibitors, remission is almost invariably short-lived and ensued by relapse and drug resistance. Hence, there is an urgent need to understand the molecular mechanisms driving drug resistance in order to prevent relapse. In this review, we discuss FLT3 as a target and highlight current understanding of FLT3 inhibitor resistance.
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Affiliation(s)
- Melat T Gebru
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Hong-Gang Wang
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA, USA. .,Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey, PA, USA. .,Penn State College of Medicine, 500 University Drive, Hershey, PA, 17033, USA.
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15
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Rai S, Tanaka H, Suzuki M, Espinoza JL, Kumode T, Tanimura A, Yokota T, Oritani K, Watanabe T, Kanakura Y, Matsumura I. Chlorpromazine eliminates acute myeloid leukemia cells by perturbing subcellular localization of FLT3-ITD and KIT-D816V. Nat Commun 2020; 11:4147. [PMID: 32811837 PMCID: PMC7434901 DOI: 10.1038/s41467-020-17666-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 07/13/2020] [Indexed: 12/14/2022] Open
Abstract
Mutated receptor tyrosine kinases (MT-RTKs) such as internal tandem duplication of FMS-like tyrosine kinase 3 (FLT3 ITD) and a point mutation KIT D816V are driver mutations for acute myeloid leukemia (AML). Clathrin assembly lymphoid myeloid leukemia protein (CALM) regulates intracellular transport of RTKs, however, the precise role for MT-RTKs remains elusive. We here show that CALM knock down leads to severely impaired FLT3 ITD- or KIT D814V-dependent cell growth compared to marginal influence on wild-type FLT3- or KIT-mediated cell growth. An antipsychotic drug chlorpromazine (CPZ) suppresses the growth of primary AML samples, and human CD34+CD38- AML cells including AML initiating cells with MT-RTKs in vitro and in vivo. Mechanistically, CPZ reduces CALM protein at post transcriptional level and perturbs the intracellular localization of MT-RTKs, thereby blocking their signaling. Our study presents a therapeutic strategy for AML with MT-RTKs by altering the intracellular localization of MT-RTKs using CPZ.
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Affiliation(s)
- Shinya Rai
- Department of Hematology and Rheumatology, Kindai University Faculty of Medicine, Osaka-sayama, Osaka, Japan
| | - Hirokazu Tanaka
- Department of Hematology and Rheumatology, Kindai University Faculty of Medicine, Osaka-sayama, Osaka, Japan.
| | - Mai Suzuki
- Division of Hematological Malignancy, National Cancer Center Research Institute, Chuo, Tokyo, Japan
| | - J Luis Espinoza
- Department of Hematology and Rheumatology, Kindai University Faculty of Medicine, Osaka-sayama, Osaka, Japan
| | - Takahiro Kumode
- Department of Hematology and Rheumatology, Kindai University Faculty of Medicine, Osaka-sayama, Osaka, Japan
| | - Akira Tanimura
- Department of Hematology and Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Takafumi Yokota
- Department of Hematology and Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Kenji Oritani
- Department of Hematology, International University of Health and Welfare, Narita, Chiba, Japan
| | - Toshio Watanabe
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara, Nara, Japan
| | - Yuzuru Kanakura
- Department of Hematology and Oncology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Itaru Matsumura
- Department of Hematology and Rheumatology, Kindai University Faculty of Medicine, Osaka-sayama, Osaka, Japan
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16
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Fortelny N, Bock C. Knowledge-primed neural networks enable biologically interpretable deep learning on single-cell sequencing data. Genome Biol 2020; 21:190. [PMID: 32746932 PMCID: PMC7397672 DOI: 10.1186/s13059-020-02100-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 07/10/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Deep learning has emerged as a versatile approach for predicting complex biological phenomena. However, its utility for biological discovery has so far been limited, given that generic deep neural networks provide little insight into the biological mechanisms that underlie a successful prediction. Here we demonstrate deep learning on biological networks, where every node has a molecular equivalent, such as a protein or gene, and every edge has a mechanistic interpretation, such as a regulatory interaction along a signaling pathway. RESULTS With knowledge-primed neural networks (KPNNs), we exploit the ability of deep learning algorithms to assign meaningful weights in multi-layered networks, resulting in a widely applicable approach for interpretable deep learning. We present a learning method that enhances the interpretability of trained KPNNs by stabilizing node weights in the presence of redundancy, enhancing the quantitative interpretability of node weights, and controlling for uneven connectivity in biological networks. We validate KPNNs on simulated data with known ground truth and demonstrate their practical use and utility in five biological applications with single-cell RNA-seq data for cancer and immune cells. CONCLUSIONS We introduce KPNNs as a method that combines the predictive power of deep learning with the interpretability of biological networks. While demonstrated here on single-cell sequencing data, this method is broadly relevant to other research areas where prior domain knowledge can be represented as networks.
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Affiliation(s)
- Nikolaus Fortelny
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Christoph Bock
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria.
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17
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Impact of NPM1/FLT3-ITD genotypes defined by the 2017 European LeukemiaNet in patients with acute myeloid leukemia. Blood 2020; 135:371-380. [PMID: 31826241 DOI: 10.1182/blood.2019002697] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 11/07/2019] [Indexed: 12/13/2022] Open
Abstract
Patients with acute myeloid leukemia (AML) harboring FLT3 internal tandem duplications (ITDs) have poor outcomes, in particular AML with a high (≥0.5) mutant/wild-type allelic ratio (AR). The 2017 European LeukemiaNet (ELN) recommendations defined 4 distinct FLT3-ITD genotypes based on the ITD AR and the NPM1 mutational status. In this retrospective exploratory study, we investigated the prognostic and predictive impact of the NPM1/FLT3-ITD genotypes categorized according to the 2017 ELN risk groups in patients randomized within the RATIFY trial, which evaluated the addition of midostaurin to standard chemotherapy. The 4 NPM1/FLT3-ITD genotypes differed significantly with regard to clinical and concurrent genetic features. Complete ELN risk categorization could be done in 318 of 549 trial patients with FLT3-ITD AML. Significant factors for response after 1 or 2 induction cycles were ELN risk group and white blood cell (WBC) counts; treatment with midostaurin had no influence. Overall survival (OS) differed significantly among ELN risk groups, with estimated 5-year OS probabilities of 0.63, 0.43, and 0.33 for favorable-, intermediate-, and adverse-risk groups, respectively (P < .001). A multivariate Cox model for OS using allogeneic hematopoietic cell transplantation (HCT) in first complete remission as a time-dependent variable revealed treatment with midostaurin, allogeneic HCT, ELN favorable-risk group, and lower WBC counts as significant favorable factors. In this model, there was a consistent beneficial effect of midostaurin across ELN risk groups.
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18
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Hamid AB, Petreaca RC. Secondary Resistant Mutations to Small Molecule Inhibitors in Cancer Cells. Cancers (Basel) 2020; 12:cancers12040927. [PMID: 32283832 PMCID: PMC7226513 DOI: 10.3390/cancers12040927] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/14/2022] Open
Abstract
Secondary resistant mutations in cancer cells arise in response to certain small molecule inhibitors. These mutations inevitably cause recurrence and often progression to a more aggressive form. Resistant mutations may manifest in various forms. For example, some mutations decrease or abrogate the affinity of the drug for the protein. Others restore the function of the enzyme even in the presence of the inhibitor. In some cases, resistance is acquired through activation of a parallel pathway which bypasses the function of the drug targeted pathway. The Catalogue of Somatic Mutations in Cancer (COSMIC) produced a compendium of resistant mutations to small molecule inhibitors reported in the literature. Here, we build on these data and provide a comprehensive review of resistant mutations in cancers. We also discuss mechanistic parallels of resistance.
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19
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The prognosis predictive value of FMS-like tyrosine kinase 3-internal tandem duplications mutant allelic ratio (FLT3-ITD MR) in patients with acute myeloid leukemia detected by GeneScan. Gene 2020; 726:144195. [DOI: 10.1016/j.gene.2019.144195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 10/18/2019] [Accepted: 10/20/2019] [Indexed: 01/04/2023]
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20
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Georgoulia PS, Bjelic S, Friedman R. Deciphering the molecular mechanism of FLT3 resistance mutations. FEBS J 2020; 287:3200-3220. [PMID: 31943770 DOI: 10.1111/febs.15209] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/13/2019] [Accepted: 01/09/2020] [Indexed: 12/18/2022]
Abstract
FMS-like tyrosine kinase 3 (FLT3) has been found to be mutated in ~ 30% of acute myeloid leukaemia patients. Small-molecule inhibitors targeting FLT3 that are currently approved or still undergoing clinical trials are subject to drug resistance due to FLT3 mutations. How these mutations lead to drug resistance is hitherto poorly understood. Herein, we studied the molecular mechanism of the drug resistance mutations D835N, Y842S and M664I, which confer resistance against the most advanced inhibitors, quizartinib and PLX3397 (pexidartinib), using enzyme kinetics and computer simulations. In vitro kinase assays were performed to measure the comparative catalytic activity of the native protein and the mutants, using a bacterial expression system developed to this aim. Our results reveal that the differential drug sensitivity profiles can be rationalised by the dynamics of the protein-drug interactions and perturbation of the intraprotein contacts upon mutations. Drug binding induced a single conformation in the native protein, whereas multiple conformations were observed otherwise (in the mutants or in the absence of drugs). The end-point kinetics measurements indicated that the three resistant mutants conferred catalytic activity that is at least as high as that of the reference without such mutations. Overall, our calculations and measurements suggest that the structural dynamics of the drug-resistant mutants that affect the active state and the increased conformational freedom of the remaining inactive drug-bound population are the two major factors that contribute to drug resistance in FLT3 harbouring cancer cells. Our results explain the mechanism of drug resistance mutations and can aid to the design of more effective tyrosine kinase inhibitors.
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Affiliation(s)
| | - Sinisa Bjelic
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Ran Friedman
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
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21
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Tao S, Wang C, Chen Y, Deng Y, Song L, Shi Y, Ling L, Ding B, He Z, Yu L. Prognosis and outcome of patients with acute myeloid leukemia based on FLT3-ITD mutation with or without additional abnormal cytogenetics. Oncol Lett 2019; 18:6766-6774. [PMID: 31807186 PMCID: PMC6876342 DOI: 10.3892/ol.2019.11051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/10/2019] [Indexed: 01/08/2023] Open
Abstract
The FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) gene mutation is present in ~20% of patients with de novo acute myeloid leukemia (AML). Patients with an FLT3-ITD mutation have a poor prognosis. However, the prognostic function of FLT3-ITD combined with other cytogenetic abnormalities are not clear. In the present study, a retrospective analysis of 103 newly diagnosed patients with AML was performed. The results revealed that the overall survival (OS) and recurrence-free survival (RFS) times were significantly longer in patients with an FLT3-ITD mutation combined with other favorable risk genes, compared with in those patients with a single FLT3-ITD mutation (P=0.0361 and P=0.0426). Sorafenib combined with chemotherapy significantly improved the overall response rate (ORR) when compared with mono-chemotherapy (P=0.039), but no significant differences were observed in the OS and RFS. In conclusion, favorable-risk cytogenetics may improve the clinical outcomes of patients with FLT3-ITD-mutated AML, but adverse-risk cytogenetics may not further worsen the prognosis. Sorafenib combined with chemotherapy may increase the ORR but would not result in a longer OS and RFS.
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Affiliation(s)
- Shandong Tao
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Chunling Wang
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Yue Chen
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Yuan Deng
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Lixiao Song
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Yuyue Shi
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Lanlan Ling
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Banghe Ding
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Zhengmei He
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
| | - Liang Yu
- Department of Hematology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, P.R. China.,Key Laboratory of Hematology of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China
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22
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Gregory MA, Nemkov T, Park HJ, Zaberezhnyy V, Gehrke S, Adane B, Jordan CT, Hansen KC, D'Alessandro A, DeGregori J. Targeting Glutamine Metabolism and Redox State for Leukemia Therapy. Clin Cancer Res 2019; 25:4079-4090. [PMID: 30940653 DOI: 10.1158/1078-0432.ccr-18-3223] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 03/02/2019] [Accepted: 03/29/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE Acute myeloid leukemia (AML) is a hematologic malignancy characterized by the accumulation of immature myeloid precursor cells. AML is poorly responsive to conventional chemotherapy and a diagnosis of AML is usually fatal. More effective and less toxic forms of therapy are desperately needed. AML cells are known to be highly dependent on the amino acid glutamine for their survival. These studies were directed at determining the effects of glutaminase inhibition on metabolism in AML and identifying general weaknesses that can be exploited therapeutically. EXPERIMENTAL DESIGN AML cancer cell lines, primary AML cells, and mouse models of AML and acute lymphoblastic leukemia (ALL) were utilized. RESULTS We show that blocking glutamine metabolism through the use of a glutaminase inhibitor (CB-839) significantly impairs antioxidant glutathione production in multiple types of AML, resulting in accretion of mitochondrial reactive oxygen species (mitoROS) and apoptotic cell death. Moreover, glutaminase inhibition makes AML cells susceptible to adjuvant drugs that further perturb mitochondrial redox state, such as arsenic trioxide (ATO) and homoharringtonine (HHT). Indeed, the combination of ATO or HHT with CB-839 exacerbates mitoROS and apoptosis, and leads to more complete cell death in AML cell lines, primary AML patient samples, and in vivo using mouse models of AML. In addition, these redox-targeted combination therapies are effective in eradicating ALL cells in vitro and in vivo. CONCLUSIONS Targeting glutamine metabolism in combination with drugs that perturb mitochondrial redox state represents an effective and potentially widely applicable therapeutic strategy for treating multiple types of leukemia.
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Affiliation(s)
- Mark A Gregory
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado.
| | - Travis Nemkov
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Hae J Park
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Vadym Zaberezhnyy
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Sarah Gehrke
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Biniam Adane
- Division of Hematology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Craig T Jordan
- Division of Hematology, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Angelo D'Alessandro
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - James DeGregori
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado.
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23
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Perez M, Blankenhorn J, Murray KJ, Parker LL. High-throughput Identification of FLT3 Wild-type and Mutant Kinase Substrate Preferences and Application to Design of Sensitive In Vitro Kinase Assay Substrates. Mol Cell Proteomics 2019; 18:477-489. [PMID: 30541869 PMCID: PMC6398213 DOI: 10.1074/mcp.ra118.001111] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/23/2018] [Indexed: 12/15/2022] Open
Abstract
Acute myeloid leukemia (AML) is an aggressive disease that is characterized by abnormal increase of immature myeloblasts in blood and bone marrow. The FLT3 receptor tyrosine kinase plays an integral role in hematopoiesis, and one third of AML diagnoses exhibit gain-of-function mutations in FLT3, with the juxtamembrane domain internal tandem duplication (ITD) and the kinase domain D835Y variants observed most frequently. Few FLT3 substrates or phosphorylation sites are known, which limits insight into FLT3's substrate preferences and makes assay design particularly challenging. We applied in vitro phosphorylation of a cell lysate digest (adaptation of the Kinase Assay Linked with Phosphoproteomics (KALIP) technique and similar methods) for high-throughput identification of substrates for three FLT3 variants (wild-type, ITD mutant, and D835Y mutant). Incorporation of identified substrate sequences as input into the KINATEST-ID substrate preference analysis and assay development pipeline facilitated the design of several peptide substrates that are phosphorylated efficiently by all three FLT3 kinase variants. These substrates could be used in assays to identify new FLT3 inhibitors that overcome resistant mutations to improve FLT3-positive AML treatment.
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Affiliation(s)
- Minervo Perez
- From the ‡University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics, 420 Washington Avenue SE, Minneapolis, Minnesota 55455
- §Purdue University, Department of Medicinal Chemistry and Molecular Pharmacology, 201 S. University Street, West Lafayette, Indiana 47907
| | - John Blankenhorn
- From the ‡University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics, 420 Washington Avenue SE, Minneapolis, Minnesota 55455
| | - Kevin J Murray
- ¶University of Minnesota, Department of Veterinary Population Medicine, 319 15 Avenue South East, Minneapolis, Minnesota 55455
| | - Laurie L Parker
- From the ‡University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics, 420 Washington Avenue SE, Minneapolis, Minnesota 55455;
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24
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Single-Cell RNA-Seq Reveals AML Hierarchies Relevant to Disease Progression and Immunity. Cell 2019; 176:1265-1281.e24. [PMID: 30827681 DOI: 10.1016/j.cell.2019.01.031] [Citation(s) in RCA: 582] [Impact Index Per Article: 116.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 12/07/2018] [Accepted: 01/17/2019] [Indexed: 02/08/2023]
Abstract
Acute myeloid leukemia (AML) is a heterogeneous disease that resides within a complex microenvironment, complicating efforts to understand how different cell types contribute to disease progression. We combined single-cell RNA sequencing and genotyping to profile 38,410 cells from 40 bone marrow aspirates, including 16 AML patients and five healthy donors. We then applied a machine learning classifier to distinguish a spectrum of malignant cell types whose abundances varied between patients and between subclones in the same tumor. Cell type compositions correlated with prototypic genetic lesions, including an association of FLT3-ITD with abundant progenitor-like cells. Primitive AML cells exhibited dysregulated transcriptional programs with co-expression of stemness and myeloid priming genes and had prognostic significance. Differentiated monocyte-like AML cells expressed diverse immunomodulatory genes and suppressed T cell activity in vitro. In conclusion, we provide single-cell technologies and an atlas of AML cell states, regulators, and markers with implications for precision medicine and immune therapies. VIDEO ABSTRACT.
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25
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Gallipoli P, Huntly BJP. Prognostic Models Turn the Heat(IT)up on FLT3ITD -Mutated AML. Clin Cancer Res 2019; 25:460-462. [PMID: 30389660 PMCID: PMC6339517 DOI: 10.1158/1078-0432.ccr-18-3146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 10/18/2018] [Accepted: 10/30/2018] [Indexed: 12/28/2022]
Abstract
The presence of internal tandem duplications (ITD) in the FLT3 receptor tyrosine kinase gene have long been known to confer a poor prognosis in patients with acute myeloid leukemia. Now, specific structural features of the ITDs are also suggested to alter patient outcome, including sensitivity to targeted therapies, prompting their evaluation in therapeutic algorithms.See related article by Schwartz et al., p. 573.
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Affiliation(s)
- Paolo Gallipoli
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Brian J P Huntly
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, United Kingdom.
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
- Cambridge Institute for Medical Research, Cambridge Biomedical Campus, Cambridge, United Kingdom
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26
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Cladribine in the remission induction of adult acute myeloid leukemia: where do we stand? Ann Hematol 2018; 98:561-579. [DOI: 10.1007/s00277-018-3562-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/16/2018] [Indexed: 01/22/2023]
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27
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Impact of FLT3 Receptor (CD135) Detection by Flow Cytometry on Clinical Outcome of Adult Acute Myeloid Leukemia Patients. CLINICAL LYMPHOMA MYELOMA & LEUKEMIA 2018; 18:541-547. [PMID: 29907544 DOI: 10.1016/j.clml.2018.05.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 05/04/2018] [Accepted: 05/17/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND The significance of FMS-like tyrosine kinase 3 (FLT3)-ITD mutation in acute myeloid leukemia (AML) prognosis has been well established. The aims of this study were to investigate the prognostic impact of the FLT3 protein (CD135) expression and its association with FLT3-ITD mutation, and to identify its role in minimal residual disease. PATIENTS AND METHODS CD135 was measured by flow cytometry on leukemic blasts of 257 adults with de novo AML. High expression of CD135 ≥ 20% was correlated with clinical, laboratory, and other prognostic factors that influenced treatment outcome. FLT3-ITD mutation was tested by PCR. RESULTS The frequency of CD135 expression was 138 (53.7%) of 257. FLT3-ITD was detected in (21.4%). Positive CD135 expression was associated with high total leukocyte count (P = .006), platelet count (P = .003), monocytic leukemia (P < .001), and CD34 (P = .008) and CD117 (P = .006) expression. CD135 expression ≥ 25% was a predictor of FLT3-ITD mutation (P = .03). CD135 overexpression was a negative predictor of complete remission and of postinduction minimal residual disease at days 14 and 28 (P < .001). CD135 had an adverse impact on overall and disease-free survival (68.5% vs. 15%, P = .002). Multivariate analysis indicated CD135 was the sole independent prognostic factor for overall survival (hazard ratio = 2.49; 95% confidence interval, 1.855-3.345; P < .001). CONCLUSION CD135 is emerging as a prognostic factor, a new marker for minimal residual disease, and a potential novel therapeutic target of AML.
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28
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Tyrosine kinase inhibitor-induced defects in DNA repair sensitize FLT3(ITD)-positive leukemia cells to PARP1 inhibitors. Blood 2018; 132:67-77. [PMID: 29784639 DOI: 10.1182/blood-2018-02-834895] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/15/2018] [Indexed: 01/03/2023] Open
Abstract
Mutations in FMS-like tyrosine kinase 3 (FLT3), such as internal tandem duplications (ITDs), can be found in up to 23% of patients with acute myeloid leukemia (AML) and confer a poor prognosis. Current treatment options for FLT3(ITD)-positive AMLs include genotoxic therapy and FLT3 inhibitors (FLT3i's), which are rarely curative. PARP1 inhibitors (PARP1i's) have been successfully applied to induce synthetic lethality in tumors harboring BRCA1/2 mutations and displaying homologous recombination (HR) deficiency. We show here that inhibition of FLT3(ITD) activity by the FLT3i AC220 caused downregulation of DNA repair proteins BRCA1, BRCA2, PALB2, RAD51, and LIG4, resulting in inhibition of 2 major DNA double-strand break (DSB) repair pathways, HR, and nonhomologous end-joining. PARP1i, olaparib, and BMN673 caused accumulation of lethal DSBs and cell death in AC220-treated FLT3(ITD)-positive leukemia cells, thus mimicking synthetic lethality. Moreover, the combination of FLT3i and PARP1i eliminated FLT3(ITD)-positive quiescent and proliferating leukemia stem cells, as well as leukemic progenitors, from human and mouse leukemia samples. Notably, the combination of AC220 and BMN673 significantly delayed disease onset and effectively reduced leukemia-initiating cells in an FLT3(ITD)-positive primary AML xenograft mouse model. In conclusion, we postulate that FLT3i-induced deficiencies in DSB repair pathways sensitize FLT3(ITD)-positive AML cells to synthetic lethality triggered by PARP1i's. Therefore, FLT3(ITD) could be used as a precision medicine marker for identifying AML patients that may benefit from a therapeutic regimen combining FLT3 and PARP1i's.
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He Y, Sun L, Xu Y, Fu L, Li Y, Bao X, Fu H, Xie C, Lou L. Combined inhibition of PI3Kδ and FLT3 signaling exerts synergistic antitumor activity and overcomes acquired drug resistance in FLT3-activated acute myeloid leukemia. Cancer Lett 2018; 420:49-59. [PMID: 29409989 DOI: 10.1016/j.canlet.2018.01.071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 01/26/2018] [Accepted: 01/27/2018] [Indexed: 12/28/2022]
Abstract
PI3Kδ and FLT3 are frequently activated in acute myeloid leukemia (AML) and have been implicated as potential therapeutic targets. In this report, we demonstrate that combined inhibition of PI3Kδ and FLT3 exerts synergistic antitumor activity in FLT3-activated AML. Synergistic antiproliferative effects were observed in FLT3-activated MV-4-11 and EOL-1 AML cell lines, but not in FLT3-independent RS4;11 and HEL cells, as demonstrated by both pharmacological inhibition and silencing of PI3Kδ/FLT3. Combined treatment with PI3Kδ and FLT3 inhibitors more effectively inhibited AKT and ERK phosphorylation, and induced apoptosis more efficiently than either agent alone. This synergistic effect was confirmed in hematopoietic 32D cells transfected with an FLT3-ITD mutant, but not FLT3 wild type. In in vivo FLT3-activated AML xenografts, a PI3Kδ inhibitor CAL101 combined with FLT3 inhibitor led to significantly enhanced antitumor activity compared with either agent alone, in association with simultaneous inhibition of AKT and ERK. Importantly, CAL101 combined with FLT3 inhibitors overcame acquired drug resistance in FLT3-ITD AML cells. Thus, combined inhibition of PI3Kδ and FLT3 may be a promising strategy in FLT3-activated AML, particularly for patients with FLT3-inhibitor-resistant mutations.
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Affiliation(s)
- Ye He
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China; University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049, China
| | - Liping Sun
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China
| | - Yongping Xu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China
| | - Li Fu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China
| | - Yun Li
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China
| | - Xubin Bao
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China
| | - Haoyu Fu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China
| | - Chengying Xie
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China.
| | - Liguang Lou
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai, 201203, China.
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Epstein DJ, Seo SK, Brown JM, Papanicolaou GA. Echinocandin prophylaxis in patients undergoing haematopoietic cell transplantation and other treatments for haematological malignancies. J Antimicrob Chemother 2018; 73:i60-i72. [PMID: 29304213 PMCID: PMC7189969 DOI: 10.1093/jac/dkx450] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Antifungal prophylaxis is the standard of care for patients undergoing intensive chemotherapy for haematological malignancy or haematopoietic cell transplantation (HCT). Prophylaxis with azoles reduces invasive fungal infections and may reduce mortality. However, breakthrough infections still occur, and the use of azoles is sometimes complicated by pharmacokinetic variability, drug interactions, adverse events and other issues. Echinocandins are highly active against Candida species, including some organisms resistant to azoles, and have some clinical activity against Aspergillus species as well. Although currently approved echinocandins require daily intravenous administration, the drugs have a favourable safety profile and more predictable pharmacokinetics than mould-active azoles. Clinical data support the efficacy and safety of echinocandins for antifungal prophylaxis in haematology and HCT patients, though data are less robust than for azoles. Notably, sparse evidence exists supporting the use of echinocandins as antifungal prophylaxis for patients with significant graft-versus-host disease (GvHD) after HCT. Two drugs that target (1,3)-β-d-glucan are in development, including an oral glucan synthase inhibitor and an echinocandin with unique pharmacokinetics permitting subcutaneous and weekly administration. Echinocandins are a reasonable alternative to azoles and other agents for antifungal prophylaxis in patients undergoing intensive chemotherapy for haematological malignancy or those receiving HCT, excluding those with significant GvHD.
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Affiliation(s)
- David J Epstein
- Division of Infectious Diseases, Stanford University, Palo Alto, CA, USA
| | - Susan K Seo
- Infectious Disease Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Janice M Brown
- Division of Infectious Diseases, Stanford University, Palo Alto, CA, USA
| | - Genovefa A Papanicolaou
- Infectious Disease Service, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Weill Cornell Medical College, New York, NY, USA
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Gallogly MM, Perl AE, Lazarus HM. Midostaurin and emerging FLT3 inhibitors for the treatment of adults with newly diagnosed acute myeloid leukemia with the FLT3 mutation. EXPERT REVIEW OF PRECISION MEDICINE AND DRUG DEVELOPMENT 2017. [DOI: 10.1080/23808993.2017.1406798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Molly M. Gallogly
- University Hospitals Cleveland Medical Center, Department of Medicine, Division of Hematology and Oncology, Cleveland, OH, USA
- Case Western Reserve University, Cleveland, OH, USA
| | - Alexander E. Perl
- University of Pennsylvania, Division of Hematology Oncology, Perelman Center for Advanced Medicine, Philadelphia, PA, USA
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Asai A, Miyata Y, Takehara K, Kanda S, Watanabe SI, Greer PA, Sakai H. Pathological significance and prognostic significance of FES expression in bladder cancer vary according to tumor grade. J Cancer Res Clin Oncol 2017; 144:21-31. [PMID: 28952025 PMCID: PMC5756570 DOI: 10.1007/s00432-017-2524-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/17/2017] [Indexed: 12/13/2022]
Abstract
Purpose The feline sarcoma oncogene protein (FES) is a non-receptor tyrosine kinase implicated in both oncogenesis and tumor suppression. Here, cancer cell lines and human tissues were employed to clarify the pathological and prognostic significance of FES in bladder cancer. Methods The relationship between FES expression and cancer aggressiveness was investigated using 3 cell lines (T24: corresponding to grade 3, 5637: corresponding to grade 2, and RT4: corresponding to grade 1) and 203 tissues derived from human bladder malignancies. Proliferation, invasion, and migration of cancer cells were assessed following the knockdown (KD) of FES expression by the siRNA method. Relationships between FES expression and pathological features, aggressiveness, and outcome were investigated. Results FES-KD inhibited the proliferation, migration, and invasion of T24 cells but not of RT4 cells and 5637 cells. Considering all patients, FES expression demonstrated a negative relationship with grade but no association with muscle invasion or cancer cell proliferation. However, it was positively correlated with pT stage and cell proliferation in high-grade tumors (p = 0.002); no such association was found for low-grade tumors. In addition, elevated FES expression was a negative prognostic indicator of metastasis after radical surgery for patients with high-grade tumors (p = 0.021) but not for those with low-grade malignancies. Conclusions FES appeared to act as a suppressor of carcinogenesis, being associated with low tumor grade in the overall patient group. However, its expression correlated with cancer aggressiveness and poor outcome in high-grade bladder cancer. FES, therefore, represents a potential therapeutic target and useful prognostic factor for such patients.
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Affiliation(s)
- Akihiro Asai
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Yasuyoshi Miyata
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
| | - Kosuke Takehara
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Shigeru Kanda
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Shin-Ichi Watanabe
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
| | - Peter A Greer
- Division of Cancer Biology and Genetics, Department of Pathology and Molecular Medicine, Queen's Cancer Research Institute, Queens University, Kingston, ON, K7L 3N6, Canada
| | - Hideki Sakai
- Department of Urology, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan
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Abstract
Whether or not FLT3 mutations are present and expressed within a leukemic hematopoietic stem cell has engendered some controversy. New evidence has now been presented on this issue that could change the way we manage the disease in the future.
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Affiliation(s)
- Mark Levis
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, MD
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