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Latent Membrane Proteins from EBV Differentially Target Cellular Pathways to Accelerate MYC-induced Lymphomagenesis. Blood Adv 2022; 6:4283-4296. [PMID: 35605249 PMCID: PMC9327557 DOI: 10.1182/bloodadvances.2022007695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/12/2022] [Indexed: 11/20/2022] Open
Abstract
EBV LMP1 enhances MYC-mediated degradation of the p27kip1 tumor suppressor and accelerates MYC-induced lymphomagenesis. EBV LMP1 and LMP2A differentially use G1-specific cell cycle and BCR-mediated signaling to accelerate MYC-induced lymphomagenesis.
MYC translocations in association with Epstein-Barr virus (EBV) infection are often observed in B-cell lymphomas. A subset of Burkitt lymphoma (BL) expresses EBV latent membrane proteins 1 and 2A (LMP1 and LMP2A) in addition to the typical restricted EBV latent gene expression. EBV-associated diffuse large B-cell lymphoma (DLBCL) typically exhibits latency type II or III and expresses LMP1. Here, we investigate the role of LMP1 in MYC-driven lymphomagenesis in our murine model. λ-MYC mice develop tumors having a “starry sky” appearance and have abnormal p53 expression that is also observed in human BL. LMP2A/λ-MYC double-transgenic mice develop tumors significantly faster than mice only expressing MYC. Similar to LMP2A/λ-MYC mice, LMP1/λ-MYC mice also have accelerated MYC-driven lymphomagenesis. As observed in LMP2A/λ-MYC mice, p27kip1 was degraded in LMP1/λ-MYC pretumor and tumor B cells. Coexpression of LMP1 and LMP2A resulted in the enhancement of B cell proliferation. In contrast to LMP2A, the inhibition of Syk or cyclin-dependant kinase (CDK)4/6 activity did not effectively inhibit LMP1-mediated MYC lymphomagenesis. Also, in contrast to LMP2A, LMP1 did not lessen abnormal p53 expression in λ-MYC tumors. To investigate the significance of LMP1 expression in human BL development, we reanalyzed RNA sequencing (RNA-Seq) data of primary human BL from previous studies. Interestingly, p53 mutations were less observed in LMP1-expressing BL, although they were not significantly changed by EBV infection, indicating LMP1 may lessen p53 mutations in human primary BL. This suggests that LMP1 effects in EBV-associated human BL vary from what we observe in our murine model. Finally, our studies suggest a novel pathogenic role of LMP1 in lymphomagenesis.
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Gallardo M, Malaney P, Aitken MJL, Zhang X, Link TM, Shah V, Alybayev S, Wu MH, Pageon LR, Ma H, Jacamo R, Yu L, Xu-Monette ZY, Steinman H, Lee HJ, Sarbassov D, Rapado I, Barton MC, Martinez-Lopez J, Bueso-Ramos C, Young KH, Post SM. Uncovering the Role of RNA-Binding Protein hnRNP K in B-Cell Lymphomas. J Natl Cancer Inst 2020; 112:95-106. [PMID: 31077320 PMCID: PMC7489062 DOI: 10.1093/jnci/djz078] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 03/22/2019] [Accepted: 04/29/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Heterogeneous nuclear ribonucleoprotein K (hnRNP K) is an RNA-binding protein that is aberrantly expressed in cancers. We and others have previously shown that reduced hnRNP K expression downmodulates tumor-suppressive programs. However, overexpression of hnRNP K is the more commonly observed clinical phenomenon, yet its functional consequences and clinical significance remain unknown. METHODS Clinical implications of hnRNP K overexpression were examined through immunohistochemistry on samples from patients with diffuse large B-cell lymphoma who did not harbor MYC alterations (n = 75). A novel transgenic mouse model that overexpresses hnRNP K specifically in B cells was generated to directly examine the role of hnRNP K overexpression in mice (three transgenic lines). Molecular consequences of hnRNP K overexpression were determined through proteomics, formaldehyde-RNA-immunoprecipitation sequencing, and biochemical assays. Therapeutic response to BET-bromodomain inhibition in the context of hnRNP K overexpression was evaluated in vitro and in vivo (n = 3 per group). All statistical tests were two-sided. RESULTS hnRNP K is overexpressed in diffuse large B-cell lymphoma patients without MYC genomic alterations. This overexpression is associated with dismal overall survival and progression-free survival (P < .001). Overexpression of hnRNP K in transgenic mice resulted in the development of lymphomas and reduced survival (P < .001 for all transgenic lines; Line 171[n = 30]: hazard ratio [HR] = 64.23, 95% confidence interval [CI] = 26.1 to 158.0; Line 173 [n = 31]: HR = 25.27, 95% CI = 10.3 to 62.1; Line 177 [n = 25]: HR = 119.5, 95% CI = 42.7 to 334.2, compared with wild-type mice). Clinical samples, mouse models, global screening assays, and biochemical studies revealed that hnRNP K's oncogenic potential stems from its ability to posttranscriptionally and translationally regulate MYC. Consequently, Hnrnpk overexpression renders cells sensitive to BET-bromodomain-inhibition in both in vitro and transplantation models, which represents a strategy for mitigating hnRNP K-mediated c-Myc activation in patients. CONCLUSION Our findings indicate that hnRNP K is a bona fide oncogene when overexpressed and represents a novel mechanism for c-Myc activation in the absence of MYC lesions.
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Affiliation(s)
- Miguel Gallardo
- Department of Leukemia
- H12O-CNIO Haematological Malignancies Clinical Research Unit, Clinical Research Programme, CNIO, Madrid, Spain
| | | | - Marisa J L Aitken
- Department of Leukemia
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences
| | | | | | - Vrutant Shah
- Department of Epigenetics and Molecular Carcinogenesis
| | | | | | | | | | | | - Li Yu
- Department of Hematopathology
| | | | | | - Hun Ju Lee
- Department of Lymphoma and Myeloma The University of Texas, MD Anderson Cancer Center, Houston, TX
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Wong JP, Stuhlmiller TJ, Giffin LC, Lin C, Bigi R, Zhao J, Zhang W, Bravo Cruz AG, Park SI, Earp HS, Dittmer DP, Frye SV, Wang X, Johnson GL, Damania B. Kinome profiling of non-Hodgkin lymphoma identifies Tyro3 as a therapeutic target in primary effusion lymphoma. Proc Natl Acad Sci U S A 2019; 116:16541-16550. [PMID: 31346082 PMCID: PMC6697815 DOI: 10.1073/pnas.1903991116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Non-Hodgkin lymphomas (NHLs) make up the majority of lymphoma diagnoses and represent a very diverse set of malignancies. We sought to identify kinases uniquely up-regulated in different NHL subtypes. Using multiplexed inhibitor bead-mass spectrometry (MIB/MS), we found Tyro3 was uniquely up-regulated and important for cell survival in primary effusion lymphoma (PEL), which is a viral lymphoma infected with Kaposi's sarcoma-associated herpesvirus (KSHV). Tyro3 was also highly expressed in PEL cell lines as well as in primary PEL exudates. Based on this discovery, we developed an inhibitor against Tyro3 named UNC3810A, which hindered cell growth in PEL, but not in other NHL subtypes where Tyro3 was not highly expressed. UNC3810A also significantly inhibited tumor progression in a PEL xenograft mouse model that was not seen in a non-PEL NHL model. Taken together, our data suggest Tyro3 is a therapeutic target for PEL.
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Affiliation(s)
- Jason P Wong
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Timothy J Stuhlmiller
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Louise C Giffin
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Carolina Lin
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Rachele Bigi
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Microbiology and Immunology and Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Jichen Zhao
- Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Weihe Zhang
- Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Ariana G Bravo Cruz
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Steven I Park
- Department of Medicine and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - H Shelton Earp
- Department of Medicine and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Dirk P Dittmer
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Microbiology and Immunology and Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Stephen V Frye
- Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Xiaodong Wang
- Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Gary L Johnson
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599;
| | - Blossom Damania
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
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The role of G-quadruplex structures of LIGS-generated aptamers R1.2 and R1.3 in IgM specific recognition. Int J Biol Macromol 2019; 133:839-849. [PMID: 31022491 DOI: 10.1016/j.ijbiomac.2019.04.141] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/17/2019] [Accepted: 04/18/2019] [Indexed: 12/27/2022]
Abstract
Exploiting a variant of SELEX called "Ligand-Guided Selection" (LI-GS), we recently identified two novel truncated G-rich aptamers, called R1.2 and R1.3, specific for membrane-bound IgM (mIgM), the hallmark of B cells. Herein, the conformational behaviour of these aptamers has been analysed by multiple biophysical methods. In order to investigate their functional secondary structures, these studies have been carried out in pseudo-physiological buffers mimicking different cellular environments. Both aptamers proved to be highly polymorphic, folding into stable, unimolecular G-quadruplex structures in K+-rich buffers. In turn, in buffered solutions containing Na+/Mg2+ ions, R1.2 and R1.3 formed mainly duplex structures. Remarkably, these aptamers were able to effectively bind mIgM on B-cell lymphoma exclusively in the presence of potassium ions. These findings demonstrate the key role of G-quadruplex folding in the molecular recognition and efficient binding of R1.2 and R1.3 to mIgM expressed in lymphoma and leukemia cells, providing a precious rational basis for the design of effective aptamer-based biosensors potentially useful for the detection of cancer-relevant biomarkers.
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Batool S, Argyropoulos KV, Azad R, Okeoma P, Zumrut H, Bhandari S, Dekhang R, Mallikaratchy PR. Dimerization of an aptamer generated from Ligand-guided selection (LIGS) yields a high affinity scaffold against B-cells. Biochim Biophys Acta Gen Subj 2018; 1863:232-240. [PMID: 30342154 DOI: 10.1016/j.bbagen.2018.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 09/13/2018] [Accepted: 10/04/2018] [Indexed: 12/18/2022]
Abstract
Nucleic Acid Aptamers (NAAs) are a class of synthetic DNA or RNA molecules that bind specifically to their target. We recently introduced an aptamer termed R1.2 against membrane Immunoglobulin M (mIgM) expressing B-cell neoplasms using Ligand Guided Selection (LIGS). While LIGS-generated aptamers are highly specific, their lower affinity prevents aptamers from being used for translational applications. Highly specific aptamers with higher affinity can increase targetability, boosting the application of aptamers as diagnostic and therapeutic molecules. Herein, we report that dimerization of R1.2, an aptamer generated from LIGS, leads to high affinity variants without compromising the specificity. Three dimeric aptamer analogues with variable linker lengths were designed to evaluate the effect of linker length in affinity. The optimized dimeric R1.2 against cultured B-cell neoplasms, four donor B-cell samples and mIgM-positive Waldenström's Macroglobulinemia (WM) showed specificity. Furthermore, confocal imaging of dimeric aptamer and anti-IgM antibody in purified B-cells suggests co-localization. Binding assays against IgM knockout Burkitt's Lymphoma cells utilizing CRISPR/Cas9 further validated specificity of dimeric R1.2. Collectively, our findings show that LIGS-generated aptamers can be re-engineered into dimeric aptamers with high specificity and affinity, demonstrating wide-range of applicability of LIGS in developing clinically practical diagnostic and therapeutic aptamers.
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Affiliation(s)
- Sana Batool
- Department of Chemistry, Lehman College, The City University of New York, 250 Bedford Park Blvd, NY 10468, USA
| | - Kimon V Argyropoulos
- Immunology Program, Memorial Sloan Kettering Cancer Center, 408 E69th street, New York, NY, 10021, USA
| | - Roksana Azad
- Ph.D. Program in Chemistry and Biochemistry, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA
| | - Precious Okeoma
- Department of Chemistry, Lehman College, The City University of New York, 250 Bedford Park Blvd, NY 10468, USA
| | - Hasan Zumrut
- Ph.D. Program in Chemistry and Biochemistry, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA
| | - Sanam Bhandari
- Department of Chemistry, Lehman College, The City University of New York, 250 Bedford Park Blvd, NY 10468, USA
| | - Rigzin Dekhang
- Department of Chemistry, Lehman College, The City University of New York, 250 Bedford Park Blvd, NY 10468, USA
| | - Prabodhika R Mallikaratchy
- Department of Chemistry, Lehman College, The City University of New York, 250 Bedford Park Blvd, NY 10468, USA; Ph.D. Program in Chemistry and Biochemistry, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA; Ph.D. Program in Molecular, Cellular and Developmental Biology, CUNY Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA.
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