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Pore D, Bodo J, Danda A, Yan D, Phillips JG, Lindner D, Hill BT, Smith MR, Hsi ED, Gupta N. Identification of Ezrin-Radixin-Moesin proteins as novel regulators of pathogenic B-cell receptor signaling and tumor growth in diffuse large B-cell lymphoma. Leukemia 2015; 29:1857-67. [PMID: 25801911 PMCID: PMC4558318 DOI: 10.1038/leu.2015.86] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 02/07/2023]
Abstract
Diffuse large B-cell lymphoma (DLBCL) is a hematological cancer associated with an aggressive clinical course. The predominant subtypes of DLBCL display features of chronic or tonic B-cell antigen receptor (BCR) signaling. However, it is not known whether the spatial organization of the BCR contributes to the regulation of pro-survival signaling pathways and cell growth. Here, we show that primary DLBCL tumors and patient-derived DLBCL cell lines contain high levels of phosphorylated Ezrin-Radixin-Moesin (ERM) proteins. The surface BCRs in both activated B cell and germinal B cell subtype DLBCL cells co-segregate with phosphoERM suggesting that the cytoskeletal network may support localized BCR signaling and contribute to pathogenesis. Indeed, ablation of membrane-cytoskeletal linkages by dominant-negative mutants, pharmacological inhibition and knockdown of ERM proteins disrupted cell surface BCR organization, inhibited proximal and distal BCR signaling, and reduced the growth of DLBCL cell lines. In vivo administration of the ezrin inhibitor retarded the growth of DLBCL tumor xenografts, concomitant with reduction in intratumor phosphoERM levels, dampened pro-survival signaling and induction of apoptosis. Our results reveal a novel ERM-based spatial mechanism that is coopted by DLBCL cells to sustain tumor cell growth and survival.
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Affiliation(s)
- D Pore
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - J Bodo
- Department of Clinical Pathology, Institute of Pathology and Laboratory Medicine, Cleveland Clinic, Cleveland, OH, USA
| | - A Danda
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - D Yan
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - J G Phillips
- Department of Translational Hematology and Oncology Research, Cleveland Clinic, Cleveland, OH, USA
| | - D Lindner
- Department of Translational Hematology and Oncology Research, Cleveland Clinic, Cleveland, OH, USA
| | - B T Hill
- Department of Hematology and Medical Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - M R Smith
- Department of Hematology and Medical Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - E D Hsi
- Department of Clinical Pathology, Institute of Pathology and Laboratory Medicine, Cleveland Clinic, Cleveland, OH, USA
| | - N Gupta
- Department of Immunology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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Chitta K, Paulus A, Akhtar S, Blake MKK, Caulfield TR, Novak AJ, Ansell SM, Advani P, Ailawadhi S, Sher T, Linder S, Chanan-Khan A. Targeted inhibition of the deubiquitinating enzymes, USP14 and UCHL5, induces proteotoxic stress and apoptosis in Waldenström macroglobulinaemia tumour cells. Br J Haematol 2015; 169:377-90. [PMID: 25691154 DOI: 10.1111/bjh.13304] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/03/2014] [Indexed: 12/17/2022]
Abstract
Deubiquitinase enzymes (DUBs) of the proteasomal 19S regulatory particle are emerging as important therapeutic targets in several malignancies. Here we demonstrate that inhibition of two proteasome-associated DUBs (USP14 and UCHL5) with the small molecule DUB inhibitor b-AP15, results in apoptosis of human Waldenström macroglobulinaemia (WM) cell lines and primary patient-derived WM tumour cells. Importantly, b-AP15 produced proteotoxic stress and apoptosis in WM cells that have acquired resistance to the proteasome inhibitor bortezomib. In silico modelling identified protein residues that were critical for the binding of b-AP15 with USP14 or UCHL5 and proteasome enzyme activity assays confirmed that b-AP15 does not affect the proteolytic capabilities of the 20S proteasome β-subunits. In vitro toxicity from b-AP15 appeared to result from a build-up of ubiquitinated proteins and activation of the endoplasmic reticulum stress response in WM cells, an effect that also disrupted the mitochondria. Focused transcriptome profiling of b-AP15-treated WM cells revealed modulation of several genes regulating cell stress and NF-κB signalling, the latter whose protein translocation and downstream target activation was reduced by b-AP15 in vitro. This is the first report to define the effects and underlying mechanisms associated with inhibition of USP14 and UCHL5 DUB activity in WM tumour cells.
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Affiliation(s)
- Kasyapa Chitta
- Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA
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Abstract
The mitogen activated protein kinase kinase kinase transforming growth factor-β-activated kinase 1 (TAK1) has emerged as an interesting therapeutic target for inflammatory diseases and cancer. TAK1 is a tightly regulated kinase that represents a key signaling node in cellular responses to inflammatory stimuli, modulating both expression of inflammatory mediators and cell death. The first inhibitors described for TAK1 exploit the active site cysteine residue found in this kinase, but more recently both type I ATP hinge-binding inhibitors and type II DFG-out inhibitors have been described. This article will review the emerging role of TAK1 kinase in inflammation, the current state of the art for small molecule inhibitor development and opportunities for chemical biology approaches.
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54
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Rossi D. Role of MYD88 in lymphoplasmacytic lymphoma diagnosis and pathogenesis. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2014; 2014:113-118. [PMID: 25696843 DOI: 10.1182/asheducation-2014.1.113] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Lymphoplasmacytic lymphoma (LPL) is a distinct B-cell lymphoproliferative disorder primarily characterized by bone marrow infiltration of lymphoplasmacytic cells. When LPL produces a serum monoclonal immunoglobulin of the IgM class, it is termed Waldenström macroglobulinemia (WM). The differential diagnosis between LPL and other types of morphologically similar B-cell tumors that may also have plasmacytic differentiation and/or secretion of IgM paraproteins is not always clear-cut based solely on the pathologic and phenotypic features of the tumor. Although the current treatments for LPL/WM are initially effective in inducing responses in most patients, they are not curative and show decreasing efficacy with repeated administrations, ultimately resulting in the selection of a chemoresistant clone. Next-generation sequencing studies have identified somatic mutations of MYD88, a key component of the Toll-like receptor signaling machinery, in ∼90% of LPL/WM. Deregulated MYD88 signaling promoted by mutations sustains tumor cell survival in LPL/WM, demonstrating that they are gain-of-function driver events in this lymphoma. This review discusses the molecular and biological mechanisms underlying MYD88 mutations in LPL/WM, the role of MYD88 mutations as molecular biomarker for the refinement of diagnosis and the improvement classification of LPL/WM, and novel targeted therapeutic strategies for LPL/WM based on the pharmacological manipulation of MYD88 signaling to which this lymphoma is addicted.
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Affiliation(s)
- Davide Rossi
- Division of Hematology, Department of Translational Medicine, Amedeo Avogadro University of Eastern Piedmont, Novara, Italy
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Chitta K, Paulus A, Caulfield TR, Akhtar S, Blake MKK, Ailawadhi S, Knight J, Heckman MG, Pinkerton A, Chanan-Khan A. Nimbolide targets BCL2 and induces apoptosis in preclinical models of Waldenströms macroglobulinemia. Blood Cancer J 2014; 4:e260. [PMID: 25382610 PMCID: PMC5424099 DOI: 10.1038/bcj.2014.74] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/15/2014] [Accepted: 09/18/2014] [Indexed: 12/31/2022] Open
Abstract
Neem leaf extract (NLE) has medicinal properties, which have been attributed to its limonoid content. We identified the NLE tetranorterpenoid, nimbolide, as being the key limonoid responsible for the cytotoxicity of NLE in various preclinical models of human B-lymphocyte cancer. Of the models tested, Waldenströms macroglobulinemia (WM) cells were most sensitive to nimbolide, undergoing significant mitochondrial mediated apoptosis. Notably, nimbolide toxicity was also observed in drug-resistant (bortezomib or ibrutinib) WM cells. To identify putative targets of nimbolide, relevant in WM, we used chemoinformatics-based approaches comprised of virtual in silico screening, molecular modeling and target–ligand reverse docking. In silico analysis revealed the antiapoptotic protein BCL2 was the preferential binding partner of nimbolide. The significance of this finding was further tested in vitro in RS4;11 (BCL2-dependent) tumor cells, in which nimbolide induced significantly more apoptosis compared with BCL2 mutated (Jurkat BCL2Ser70-Ala) cells. Lastly, intraperitoneal administration of nimbolide in WM tumor xenografted mice, significantly reduced tumor growth and IgM secretion in vivo, while modulating the expression of several proteins as seen on immunohistochemistry. Overall, our data demonstrate that nimbolide is highly active in WM cells, as well as other B-cell cancers, and engages BCL2 to exert its cytotoxic activity.
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Affiliation(s)
- K Chitta
- Department of Cancer Biology, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA
| | - A Paulus
- Department of Cancer Biology, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA
| | - T R Caulfield
- Department of Molecular Neuroscience, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA
| | - S Akhtar
- Department of Cancer Biology, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA
| | - M-K K Blake
- Department of Cancer Biology, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA
| | - S Ailawadhi
- Division of Hematology and Oncology, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA
| | - J Knight
- Department of Cancer Biology, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA
| | - M G Heckman
- Department of Health Science Research, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA
| | - A Pinkerton
- Conrad Prebys Center for Chemical Genomics at Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - A Chanan-Khan
- Division of Hematology and Oncology, Mayo Clinic, 4500 San Pablo Road South, Jacksonville, FL, USA
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Cao Y, Hunter ZR, Liu X, Xu L, Yang G, Chen J, Tsakmaklis N, Kanan S, Castillo JJ, Treon SP. CXCR4 WHIM-like frameshift and nonsense mutations promote ibrutinib resistance but do not supplant MYD88(L265P) -directed survival signalling in Waldenström macroglobulinaemia cells. Br J Haematol 2014; 168:701-7. [PMID: 25371371 DOI: 10.1111/bjh.13200] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/12/2014] [Indexed: 12/28/2022]
Abstract
CXCR4(WHIM) frameshift and nonsense mutations follow MYD88(L265P) as the most common somatic variants in Waldenström Macroglobulinaemia (WM), and impact clinical presentation and ibrutinib response. While the nonsense (CXCR4(S338X) ) mutation has been investigated, little is known about CXCR4 frameshift (CXCR4(FS) ) mutations. We engineered WM cells to express CXCR4(FS) mutations present in patients, and compared their CXCL12 (SDF-1a) induced signalling and ibrutinib sensitivity to CXCR4(wild-type (WT)) and CXCR4(S338X) cells. Following CXCL12 stimulation, CXCR4(FS) and CXCR4(S338X) WM cells showed impaired CXCR4 receptor internalization, and enhanced AKT1 (also termed AKT) and MAPK1 (also termed ERK) activation versus CXCR(WT) cells (P < 0·05), though MAPK1 activation was more prolonged in CXCR4(S338X) cells (P < 0·05). CXCR4(FS) and CXCR4(S338X) cells, but not CXCR4(WT) cells, were rescued from ibrutinib-triggered apoptosis by CXCL12 that was reversed by AKT1, MAPK1 or CXCR4 antagonists. Treatment with an inhibitor that blocks MYD88(L265P) signalling triggered similar levels of apoptosis that was not abrogated by CXCL12 treatment in CXCR4(WT) and CXCR4(WHIM) cells. These studies show a functional role for CXCR4(FS) mutations in WM, and provide a framework for the investigation of CXCR4 antagonists with ibrutinib in CXCR4(WHIM) -mutated WM patients. Direct inhibition of MYD88(L265P) signalling overcomes CXCL12 triggered survival effects in CXCR4(WHIM) -mutated cells supporting a primary role for this survival pathway in WM.
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Affiliation(s)
- Yang Cao
- Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
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Activation of lymphoma-associated MyD88 mutations via allostery-induced TIR-domain oligomerization. Blood 2014; 124:3896-904. [PMID: 25359991 DOI: 10.1182/blood-2014-05-573188] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Myeloid differentiation 88 (MyD88) is the key signaling adapter of Toll-like and interleukin-1 receptors. Recurrent lymphoma-associated mutations, particularly Leu265Pro (L265P), within the MyD88 Toll/interleukin-1 receptor (TIR) domain sustain lymphoma cell survival due to constitutive nuclear factor κB signaling. We found that mutated TIR domains displayed an intrinsic propensity for augmented oligomerization and spontaneous formation of cytosolic Myddosome aggregates in lymphoma cell lines, mimicking the effect of dimerized TIR domains. Blocking of MyD88 oligomerization induced apoptosis. The L265P TIR domain can recruit the endogenous wild-type MyD88 for oligomer formation and hyperactivity. Molecular dynamics simulations and analysis of additional mutations suggest that constitutive activity is caused by allosteric oligomerization.
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Bohers E, Mareschal S, Bertrand P, Viailly PJ, Dubois S, Maingonnat C, Ruminy P, Tilly H, Jardin F. Activating somatic mutations in diffuse large B-cell lymphomas: lessons from next generation sequencing and key elements in the precision medicine era. Leuk Lymphoma 2014; 56:1213-22. [DOI: 10.3109/10428194.2014.941836] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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60
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MYD88 and beyond: novel opportunities for diagnosis, prognosis and treatment in Waldenström’s Macroglobulinemia. Leukemia 2014; 28:1799-803. [DOI: 10.1038/leu.2014.88] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/13/2014] [Accepted: 01/15/2014] [Indexed: 12/28/2022]
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