1
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Screen M, Matheson LS, Howden AJ, Strathdee D, Willis AE, Bushell M, Sansom O, Turner M. RNA helicase EIF4A1-mediated translation is essential for the GC response. Life Sci Alliance 2024; 7:e202302301. [PMID: 38011999 PMCID: PMC10681908 DOI: 10.26508/lsa.202302301] [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: 07/31/2023] [Revised: 11/09/2023] [Accepted: 11/09/2023] [Indexed: 11/29/2023] Open
Abstract
EIF4A1 and cofactors EIF4B and EIF4H have been well characterised in cancers, including B cell malignancies, for their ability to promote the translation of oncogenes with structured 5' untranslated regions. However, very little is known of their roles in nonmalignant cells. Using mouse models to delete Eif4a1, Eif4b or Eif4h in B cells, we show that EIF4A1, but not EIF4B or EIF4H, is essential for B cell development and the germinal centre response. After B cell activation in vitro, EIF4A1 facilitates an increased rate of protein synthesis, MYC expression, and expression of cell cycle regulators. However, EIF4A1-deficient cells remain viable, whereas inhibition of EIF4A1 and EIF4A2 by Hippuristanol treatment induces cell death.
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Affiliation(s)
- Michael Screen
- Immunology Programme, The Babraham Institute, Babraham Research Campus, Cambridge, UK
| | - Louise S Matheson
- Immunology Programme, The Babraham Institute, Babraham Research Campus, Cambridge, UK
| | - Andrew Jm Howden
- Cell Signalling and Immunology, University of Dundee, Dundee, UK
| | | | - Anne E Willis
- MRC Toxicology Unit, University of Cambridge, Cambridge, UK
| | - Martin Bushell
- Cancer Research UK Beatson Institute, Glasgow, UK
- School of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Owen Sansom
- Cancer Research UK Beatson Institute, Glasgow, UK
- School of Cancer Sciences, University of Glasgow, Glasgow, UK
| | - Martin Turner
- Immunology Programme, The Babraham Institute, Babraham Research Campus, Cambridge, UK
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2
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Largeot A, Klapp V, Viry E, Gonder S, Fernandez Botana I, Blomme A, Benzarti M, Pierson S, Duculty C, Marttila P, Wierz M, Gargiulo E, Pagano G, An N, El Hachem N, Perez Hernandez D, Chakraborty S, Ysebaert L, François JH, Cortez Clemente S, Berchem G, Efremov DG, Dittmar G, Szpakowska M, Chevigné A, Nazarov PV, Helleday T, Close P, Meiser J, Stamatopoulos B, Désaubry L, Paggetti J, Moussay E. Inhibition of MYC translation through targeting of the newly identified PHB-eIF4F complex as a therapeutic strategy in CLL. Blood 2023; 141:3166-3183. [PMID: 37084385 PMCID: PMC10646824 DOI: 10.1182/blood.2022017839] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 02/08/2023] [Accepted: 03/05/2023] [Indexed: 04/23/2023] Open
Abstract
Dysregulation of messenger RNA (mRNA) translation, including preferential translation of mRNA with complex 5' untranslated regions such as the MYC oncogene, is recognized as an important mechanism in cancer. Here, we show that both human and murine chronic lymphocytic leukemia (CLL) cells display a high translation rate, which is inhibited by the synthetic flavagline FL3, a prohibitin (PHB)-binding drug. A multiomics analysis performed in samples from patients with CLL and cell lines treated with FL3 revealed the decreased translation of the MYC oncogene and of proteins involved in cell cycle and metabolism. Furthermore, inhibiting translation induced a proliferation arrest and a rewiring of MYC-driven metabolism. Interestingly, contrary to other models, the RAS-RAF-(PHBs)-MAPK pathway is neither impaired by FL3 nor implicated in translation regulation in CLL cells. Here, we rather show that PHBs are directly associated with the eukaryotic initiation factor (eIF)4F translation complex and are targeted by FL3. Knockdown of PHBs resembled FL3 treatment. Importantly, inhibition of translation controlled CLL development in vivo, either alone or combined with immunotherapy. Finally, high expression of translation initiation-related genes and PHBs genes correlated with poor survival and unfavorable clinical parameters in patients with CLL. Overall, we demonstrated that translation inhibition is a valuable strategy to control CLL development by blocking the translation of several oncogenic pathways including MYC. We also unraveled a new and direct role of PHBs in translation initiation, thus creating new therapeutic opportunities for patients with CLL.
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MESH Headings
- Humans
- Mice
- Animals
- Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Eukaryotic Initiation Factor-4F/genetics
- Prohibitins
- Genes, myc
- RNA, Messenger/genetics
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Affiliation(s)
- Anne Largeot
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Vanessa Klapp
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
- Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Elodie Viry
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Susanne Gonder
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
- Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Iria Fernandez Botana
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
- Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Arnaud Blomme
- Laboratory of Cancer Signaling, GIGA Stem Cells, University of Liège, Liège, Belgium
| | - Mohaned Benzarti
- Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
- Department of Cancer Research, Cancer Metabolism Group, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Sandrine Pierson
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Chloé Duculty
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
- Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Petra Marttila
- Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet, Solna, Sweden
| | - Marina Wierz
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Ernesto Gargiulo
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Giulia Pagano
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
- Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Ning An
- Laboratory of Cancer Signaling, GIGA Stem Cells, University of Liège, Liège, Belgium
| | - Najla El Hachem
- Laboratory of Cancer Signaling, GIGA Stem Cells, University of Liège, Liège, Belgium
| | - Daniel Perez Hernandez
- Department of Infection and Immunity, Proteomics of Cellular Signaling, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Supriya Chakraborty
- Molecular Hematology, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Loïc Ysebaert
- Haematology Department, Institut Universitaire du Cancer Toulouse Oncopole, Toulouse, France
| | - Jean-Hugues François
- Laboratoire d’hématologie, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg
| | - Susan Cortez Clemente
- Département d’hémato-oncologie, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg
| | - Guy Berchem
- Département d’hémato-oncologie, Centre Hospitalier de Luxembourg, Luxembourg, Luxembourg
- Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Dimitar G. Efremov
- Molecular Hematology, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Gunnar Dittmar
- Department of Infection and Immunity, Proteomics of Cellular Signaling, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
- Department of Life Sciences and Medicine, University of Luxembourg, Belvaux, Luxembourg
| | - Martyna Szpakowska
- Department of Infection and Immunity, Immuno-Pharmacology and Interactomics, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Andy Chevigné
- Department of Infection and Immunity, Immuno-Pharmacology and Interactomics, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Petr V. Nazarov
- Department of Cancer Research, Multiomics Data Science, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Thomas Helleday
- Department of Oncology-Pathology, Science for Life Laboratory, Karolinska Institutet, Solna, Sweden
- Department of Oncology and Metabolism, Weston Park Cancer Centre, The Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Pierre Close
- Laboratory of Cancer Signaling, GIGA Stem Cells, University of Liège, Liège, Belgium
- WELBIO Department, WEL Research Institute, Wavre, Belgium
| | - Johannes Meiser
- Department of Cancer Research, Cancer Metabolism Group, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Basile Stamatopoulos
- Laboratory of Clinical Cell Therapy, ULB-Research Cancer Center, Jules Bordet Institute, Université Libre de Bruxelles, Brussels, Belgium
| | - Laurent Désaubry
- Regenerative Nanomedicine Laboratory (UMR1260), Faculty of Medicine, Fédération de Médecine Translationnelle de Strasbourg, INSERM-University of Strasbourg, Strasbourg, France
| | - Jérôme Paggetti
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Etienne Moussay
- Department of Cancer Research, Tumor Stroma Interactions, Luxembourg Institute of Health, Luxembourg, Luxembourg
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Melnik BC, Stadler R, Weiskirchen R, Leitzmann C, Schmitz G. Potential Pathogenic Impact of Cow’s Milk Consumption and Bovine Milk-Derived Exosomal MicroRNAs in Diffuse Large B-Cell Lymphoma. Int J Mol Sci 2023; 24:ijms24076102. [PMID: 37047075 PMCID: PMC10094152 DOI: 10.3390/ijms24076102] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/05/2023] [Accepted: 03/16/2023] [Indexed: 03/29/2023] Open
Abstract
Epidemiological evidence supports an association between cow’s milk consumption and the risk of diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma worldwide. This narrative review intends to elucidate the potential impact of milk-related agents, predominantly milk-derived exosomes (MDEs) and their microRNAs (miRs) in lymphomagenesis. Upregulation of PI3K-AKT-mTORC1 signaling is a common feature of DLBCL. Increased expression of B cell lymphoma 6 (BCL6) and suppression of B lymphocyte-induced maturation protein 1 (BLIMP1)/PR domain-containing protein 1 (PRDM1) are crucial pathological deviations in DLBCL. Translational evidence indicates that during the breastfeeding period, human MDE miRs support B cell proliferation via epigenetic upregulation of BCL6 (via miR-148a-3p-mediated suppression of DNA methyltransferase 1 (DNMT1) and miR-155-5p/miR-29b-5p-mediated suppression of activation-induced cytidine deaminase (AICDA) and suppression of BLIMP1 (via MDE let-7-5p/miR-125b-5p-targeting of PRDM1). After weaning with the physiological termination of MDE miR signaling, the infant’s BCL6 expression and B cell proliferation declines, whereas BLIMP1-mediated B cell maturation for adequate own antibody production rises. Because human and bovine MDE miRs share identical nucleotide sequences, the consumption of pasteurized cow’s milk in adults with the continued transfer of bioactive bovine MDE miRs may de-differentiate B cells back to the neonatal “proliferation-dominated” B cell phenotype maintaining an increased BLC6/BLIMP1 ratio. Persistent milk-induced epigenetic dysregulation of BCL6 and BLIMP1 expression may thus represent a novel driving mechanism in B cell lymphomagenesis. Bovine MDEs and their miR cargo have to be considered potential pathogens that should be removed from the human food chain.
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4
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Taylor J, Wilmore S, Marriot S, Rogers-Broadway KR, Fell R, Minton AR, Branch T, Ashton-Key M, Coldwell M, Stevenson FK, Forconi F, Steele AJ, Packham G, Yeomans A. B-cell receptor signaling induces proteasomal degradation of PDCD4 via MEK1/2 and mTORC1 in malignant B cells. Cell Signal 2022; 94:110311. [PMID: 35306137 PMCID: PMC9077442 DOI: 10.1016/j.cellsig.2022.110311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 03/11/2022] [Accepted: 03/13/2022] [Indexed: 12/12/2022]
Abstract
B-cell receptor (BCR) signaling plays a major role in the pathogenesis of B-cell malignancies and is an established target for therapy, including in chronic lymphocytic leukemia cells (CLL), the most common B-cell malignancy. We previously demonstrated that activation of BCR signaling in primary CLL cells downregulated expression of PDCD4, an inhibitor of the translational initiation factor eIF4A and a potential tumor suppressor in lymphoma. Regulation of the PDCD4/eIF4A axis appeared to be important for expression of the MYC oncoprotein as MYC mRNA translation was increased following BCR stimulation and MYC protein induction was repressed by pharmacological inhibition of eIF4A. Here we show that MYC expression is also associated with PDCD4 down-regulation in CLL cells in vivo and characterize the signaling pathways that mediate BCR-induced PDCD4 down-regulation in CLL and lymphoma cells. PDCD4 downregulation was mediated by proteasomal degradation as it was inhibited by proteasome inhibitors in both primary CLL cells and B-lymphoma cell lines. In lymphoma cells, PDCD4 degradation was predominantly dependent on signaling via the AKT pathway. By contrast, in CLL cells, both ERK and AKT pathways contributed to PDCD4 down-regulation and dual inhibition using ibrutinib with either MEK1/2 or mTORC1 inhibition was required to fully reverse PDCD4 down-regulation. Consistent with this, dual inhibition of BTK with MEK1/2 or mTORC1 resulted in the strongest inhibition of BCR-induced MYC expression. This study provides important new insight into the regulation of mRNA translation in B-cell malignancies and a rationale for combinations of kinase inhibitors to target translation control and MYC expression.
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Affiliation(s)
- Joe Taylor
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Sarah Wilmore
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Sophie Marriot
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Karly-Rai Rogers-Broadway
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Rachel Fell
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Annabel R Minton
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Tom Branch
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Meg Ashton-Key
- Department of Cellular Pathology, Southampton General Hospital, Southampton, United Kingdom
| | - Mark Coldwell
- Centre for Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, United Kingdom
| | - Freda K Stevenson
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Francesco Forconi
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Andrew J Steele
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Graham Packham
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.
| | - Alison Yeomans
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
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5
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Kapadia BB, Roychowdhury A, Kayastha F, Nanaji N, Gartenhaus RB. PARK2 regulates eIF4B-driven lymphomagenesis. Mol Cancer Res 2022; 20:molcanres.MCR-21-0729-A.2021. [PMID: 35191952 PMCID: PMC9339581 DOI: 10.1158/1541-7786.mcr-21-0729] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/07/2021] [Accepted: 01/26/2022] [Indexed: 01/09/2023]
Abstract
Patients with high-risk diffuse large B-cell lymphoma (DLBCL) have poor outcomes following first-line cyclophosphamide, doxorubicin, vincristine, prednisone, and rituximab (R-CHOP); thus, treatment of this fatal disease remains an area of unmet medical need and requires identification of novel therapeutic approaches. Dysregulation of protein translation initiation has emerged as a common downstream node in several malignancies, including lymphoma. Ubiquitination, a prominent post-translational modification associated with substrate degradation, has recently been shown to be a key modulator of nascent peptide synthesis by limiting several translational initiation factors. While a few deubiquitinases have been identified, the E3-ligase responsible for the critical ubiquitination of these translational initiation factors is still unknown. In this study, using complementary cellular models along with clinical readouts, we establish that PARK2 ubiquitinates eIF4B and consequently regulates overall protein translational activity. The formation of this interaction depends on upstream signaling, which is negatively regulated at the protein level of PARK2. Through biochemical, mutational, and genetic studies, we identified PARK2 as a mTORC1 substrate. mTORC1 phosphorylates PARK2 at Ser127, which blocks its cellular ubiquitination activity, thereby hindering its tumor suppressor effect on eIF4B's stability. This resultant increase of eIF4B protein level helps drive enhanced overall protein translation. These data support a novel paradigm in which PARK2-generated eIF4B ubiquitination serves as an anti-oncogenic intracellular inhibitor of protein translation, attenuated by mTORC1 signaling. Implications: Our data implicates the FASN/mTOR-PARK2-eIF4B axis as a critical driver of enhanced oncogene expression contributing to lymphomagenesis.
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Affiliation(s)
- Bandish B. Kapadia
- Section of Hematology and Oncology, Medicine Service, McGuire Cancer Center, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
- Division of Hematology, Oncology, and Palliative Care, Department of Internal Medicine, Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
| | - Anirban Roychowdhury
- Section of Hematology and Oncology, Medicine Service, McGuire Cancer Center, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
- Division of Hematology, Oncology, and Palliative Care, Department of Internal Medicine, Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
| | - Forum Kayastha
- Section of Hematology and Oncology, Medicine Service, McGuire Cancer Center, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
- Division of Hematology, Oncology, and Palliative Care, Department of Internal Medicine, Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
| | - Nahid Nanaji
- Department of Veteran Affairs, Maryland Healthcare System, Baltimore, Maryland
| | - Ronald B. Gartenhaus
- Section of Hematology and Oncology, Medicine Service, McGuire Cancer Center, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
- Division of Hematology, Oncology, and Palliative Care, Department of Internal Medicine, Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia
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6
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Forconi F, Lanham SA, Chiodin G. Biological and Clinical Insight from Analysis of the Tumor B-Cell Receptor Structure and Function in Chronic Lymphocytic Leukemia. Cancers (Basel) 2022; 14:663. [PMID: 35158929 PMCID: PMC8833472 DOI: 10.3390/cancers14030663] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 02/04/2023] Open
Abstract
The B-cell receptor (BCR) is essential to the behavior of the majority of normal and neoplastic mature B cells. The identification in 1999 of the two major CLL subsets expressing unmutated immunoglobulin (Ig) variable region genes (U-IGHV, U-CLL) of pre-germinal center origin and poor prognosis, and mutated IGHV (M-CLL) of post-germinal center origin and good prognosis, ignited intensive investigations on structure and function of the tumor BCR. These investigations have provided fundamental insight into CLL biology and eventually the mechanistic rationale for the development of successful therapies targeting BCR signaling. U-CLL and M-CLL are characterized by variable low surface IgM (sIgM) expression and signaling capacity. Variability of sIgM can in part be explained by chronic engagement with (auto)antigen at tissue sites. However, other environmental elements, genetic changes, and epigenetic signatures also contribute to the sIgM variability. The variable levels have consequences on the behavior of CLL, which is in a state of anergy with an indolent clinical course when sIgM expression is low, or pushed towards proliferation and a more aggressive clinical course when sIgM expression is high. Efficacy of therapies that target BTK may also be affected by the variable sIgM levels and signaling and, in part, explain the development of resistance.
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Affiliation(s)
- Francesco Forconi
- School of Cancer Sciences, Cancer Research UK and NIHR Experimental Cancer Medicine Centres, University of Southampton, Southampton SO16 6YD, UK; (S.A.L.); (G.C.)
- Department of Haematology, University Hospital Southampton NHS Trust, Southampton SO16 6YD, UK
| | - Stuart A. Lanham
- School of Cancer Sciences, Cancer Research UK and NIHR Experimental Cancer Medicine Centres, University of Southampton, Southampton SO16 6YD, UK; (S.A.L.); (G.C.)
| | - Giorgia Chiodin
- School of Cancer Sciences, Cancer Research UK and NIHR Experimental Cancer Medicine Centres, University of Southampton, Southampton SO16 6YD, UK; (S.A.L.); (G.C.)
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Greger H. Comparative phytochemistry of flavaglines (= rocaglamides), a group of highly bioactive flavolignans from Aglaia species (Meliaceae). PHYTOCHEMISTRY REVIEWS : PROCEEDINGS OF THE PHYTOCHEMICAL SOCIETY OF EUROPE 2022; 21:725-764. [PMID: 34104125 PMCID: PMC8176878 DOI: 10.1007/s11101-021-09761-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 05/17/2021] [Indexed: 05/07/2023]
Abstract
Flavaglines are formed by cycloaddition of a flavonoid nucleus with a cinnamic acid moiety representing a typical chemical character of the genus Aglaia of the family Meliaceae. Based on biosynthetic considerations 148 derivatives are grouped together into three skeletal types representing 77 cyclopenta[b]benzofurans, 61 cyclopenta[bc]benzopyrans, and 10 benzo[b]oxepines. Apart from different hydroxy, methoxy, and methylenedioxy groups of the aromatic rings, important structural variation is created by different substitutions and stereochemistries of the central cyclopentane ring. Putrescine-derived bisamides constitute important building blocks occurring as cyclic 2-aminopyrrolidines or in an open-chained form, and are involved in the formation of pyrimidinone flavaglines. Regarding the central role of cinnamic acid in the formation of the basic skeleton, rocagloic acid represents a biosynthetic precursor from which aglafoline- and rocaglamide-type cyclopentabenzofurans can be derived, while those of the rocaglaol-type are the result of decarboxylation. Broad-based comparison revealed characteristic substitution trends which contribute as chemical markers to natural delimitation and grouping of taxonomically problematic Aglaia species. A wide variety of biological activities ranges from insecticidal, antifungal, antiprotozoal, and anti-inflammatory properties, especially to pronounced anticancer and antiviral activities. The high insecticidal activity of flavaglines is comparable with that of the well-known natural insecticide azadirachtin. Comparative feeding experiments informed about structure-activity relationships and exhibited different substitutions of the cyclopentane ring essential for insecticidal activity. Parallel studies on the antiproliferative activity of flavaglines in various tumor cell lines revealed similar structural prerequisites that let expect corresponding molecular mechanisms. An important structural modification with very high cytotoxic potency was found in the benzofuran silvestrol characterized by an unusual dioxanyloxy subunit. It possessed comparable cytotoxicity to that of the natural anticancer compounds paclitaxel (Taxol®) and camptothecin without effecting normal cells. The primary effect was the inhibition of protein synthesis by binding to the translation initiation factor eIF4A, an ATP-dependent DEAD-box RNA helicase. Flavaglines were also shown to bind to prohibitins (PHB) responsible for regulation of important signaling pathways, and to inhibit the transcriptional factor HSF1 deeply involved in metabolic programming, survival, and proliferation of cancer cells. Flavaglines were shown to be not only promising anticancer agents but gained now also high expectations as agents against emerging RNA viruses like SARS-CoV-2. Targeting the helicase eIF4A with flavaglines was recently described as pan-viral strategy for minimizing the impact of future RNA virus pandemics.
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Affiliation(s)
- Harald Greger
- Chemodiversity Research Group, Faculty of Life Sciences, University of Vienna, Rennweg 14, 1030 Wien, Austria
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8
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Wilmore S, Rogers-Broadway KR, Taylor J, Lemm E, Fell R, Stevenson FK, Forconi F, Steele AJ, Coldwell M, Packham G, Yeomans A. Targeted inhibition of eIF4A suppresses B-cell receptor-induced translation and expression of MYC and MCL1 in chronic lymphocytic leukemia cells. Cell Mol Life Sci 2021; 78:6337-6349. [PMID: 34398253 PMCID: PMC8429177 DOI: 10.1007/s00018-021-03910-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 07/09/2021] [Accepted: 08/02/2021] [Indexed: 12/18/2022]
Abstract
Signaling via the B-cell receptor (BCR) is a key driver and therapeutic target in chronic lymphocytic leukemia (CLL). BCR stimulation of CLL cells induces expression of eIF4A, an initiation factor important for translation of multiple oncoproteins, and reduces expression of PDCD4, a natural inhibitor of eIF4A, suggesting that eIF4A may be a critical nexus controlling protein expression downstream of the BCR in these cells. We, therefore, investigated the effect of eIF4A inhibitors (eIF4Ai) on BCR-induced responses. We demonstrated that eIF4Ai (silvestrol and rocaglamide A) reduced anti-IgM-induced global mRNA translation in CLL cells and also inhibited accumulation of MYC and MCL1, key drivers of proliferation and survival, respectively, without effects on upstream signaling responses (ERK1/2 and AKT phosphorylation). Analysis of normal naïve and non-switched memory B cells, likely counterparts of the two main subsets of CLL, demonstrated that basal RNA translation was higher in memory B cells, but was similarly increased and susceptible to eIF4Ai-mediated inhibition in both. We probed the fate of MYC mRNA in eIF4Ai-treated CLL cells and found that eIF4Ai caused a profound accumulation of MYC mRNA in anti-IgM treated cells. This was mediated by MYC mRNA stabilization and was not observed for MCL1 mRNA. Following drug wash-out, MYC mRNA levels declined but without substantial MYC protein accumulation, indicating that stabilized MYC mRNA remained blocked from translation. In conclusion, BCR-induced regulation of eIF4A may be a critical signal-dependent nexus for therapeutic attack in CLL and other B-cell malignancies, especially those dependent on MYC and/or MCL1.
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MESH Headings
- Antibodies, Anti-Idiotypic/pharmacology
- Benzofurans/pharmacology
- Cells, Cultured
- Eukaryotic Initiation Factor-4A/antagonists & inhibitors
- Eukaryotic Initiation Factor-4A/metabolism
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Leukocytes, Mononuclear/cytology
- Leukocytes, Mononuclear/drug effects
- Leukocytes, Mononuclear/metabolism
- Myeloid Cell Leukemia Sequence 1 Protein/genetics
- Myeloid Cell Leukemia Sequence 1 Protein/metabolism
- Protein Biosynthesis/drug effects
- Proto-Oncogene Proteins c-myc/genetics
- Proto-Oncogene Proteins c-myc/metabolism
- RNA Stability/drug effects
- RNA, Messenger/metabolism
- Receptors, Antigen, B-Cell/metabolism
- Signal Transduction/drug effects
- Triterpenes/pharmacology
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Affiliation(s)
- Sarah Wilmore
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK
| | - Karly-Rai Rogers-Broadway
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK
| | - Joe Taylor
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK
| | - Elizabeth Lemm
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK
| | - Rachel Fell
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK
| | - Freda K Stevenson
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK
| | - Francesco Forconi
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK
| | - Andrew J Steele
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK
| | - Mark Coldwell
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
| | - Graham Packham
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK.
| | - Alison Yeomans
- Cancer Research UK Centre, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Somers Building, Southampton, SO16 6YD, UK
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