SIRT1 and HSP90alpha Are Functionally Linked and Control Mitotic Chromosome Segregation and Cell Viability in a Subset of Dlbcls

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 28-29
Author(s):  
Emilia Bialopiotrowicz ◽  
Monika Noyszewska-Kania ◽  
Ewa Jabłońska ◽  
Tomasz Sewastianik ◽  
Monika Stańczak ◽  
...  
Keyword(s):  
Heat Shock ◽  
B Cell ◽  
Cell Lines ◽  
Chromosome Segregation ◽  
B Cell Lymphoma ◽  
Hsp90 Inhibitor ◽  
Proximity Ligation Assay ◽  
Functional Link ◽  
Chromosome Dynamics ◽  
Number Of Cells

Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive non-Hodgkin lymphoma in adults, exhibiting highly heterogenous clinical behavior and complex molecular background. In addition to the genetic complexity, different DLBCL subsets are functionally dependent on different survival mechanisms and exhibit distinct metabolic fingerprints. One of DLBCLs subtypes relies on mitochondrial oxidative phosphorylation and nutrient utilization pathways that provide pro-survival advantage independent of B-cell receptor (BCR) signaling. These OxPhos-DLBCLs are resistant to BCR inhibition and remain functionally poorly defined. We and others found that OxPhos-DLBCLs, compared to the BCR-dependent DLBCLs, overexpress heat shock protein HSP90alpha (Br J Haematol 2009; 144:358-66). Expression of multiple heat shock proteins is regulated by the activity of a stress-responsive, acetylation-dependent transcription factor HSF1. Acetylation blocks, whereas deacetylation by sirtuins increases HSF1 activity. We found that HSP90alpha gene/protein expression correlated with SIRT1 protein level in DLBCL cell lines. SIRT1 knockdown or chemical inhibition reduced HSP90alpha expression in a mechanism involving HSF1, whereas HSP90 inhibitor (17AAG) reduced SIRT1 protein stability suggesting a chaperone function of HSP90alpha toward SIRT1 and a functional link between these proteins. We confirmed the SIRT1-HSP90alpha interaction in DLBCL cells using proximity ligation assay (PLA). The number of PLA complexes was significantly higher in OxPhos- (Ly4, K422, Toledo) than BCR- (Ly1, DHL4, Ly7, DHL6) DLBCL cell lines (p<0.001). Importantly, the number of PLA complexes increased markedly in mitotic when compared to interphase cells, indicating that the interaction between these proteins plays a mitosis-specific role. For this reason, we next assessed the chromosome segregation of DLBCL cells in the presence and absence of SIRT1 and/or HSP90alpha activity. Both genetic (siRNA) and chemical (EX-527) inhibition of SIRT1 significantly increased the number of cells with chromosome segregation errors (multipolar spindle formation, anaphase bridges and lagging chromosomes- respectively 50%, 26% and 20% of all observed abnormal mitotic incidents). Similarly, chemical (17AAG) or genetic (siRNA) inhibition of HSP90alpha disturbed chromosome segregation, albeit to a lesser extent than SIRT1 disruption. Concurrent chemical or genetic ablation of SIRT1 and HSP90alpha synergistically increased the number of mitotic cells with chromosome segregation errors in OxPhos-DLBCLs. In the BCR-dependent cell lines, neither of the inhibitors used separately had a significant impact on the number of cells with improper chromosome segregation events, but the simultaneous inhibition of SIRT1 (EX-527) and HSP90alpha (17AAG) significantly increased the number of cells with aberrant mitosis, although to a lesser extent than in OxPhos-DLBCLs (15.4-17.1% for BCR-DLBCL versus 28.37-48% for OxPhos-DLBCL, respectively). Consistent with the postulated role of SIRT1 in chromosome dynamics during mitosis, we found downregulated expression of SIRT1-dependent genes in the recently characterized DLBCL subset characterized by chromosome instability (C2, Chapuy et al., Nat Medicine 2018). While low rates of chromosomal instability induces tumorigenesis, increased chromosomal missegregaton leads to cell death and suppresses cancer development. SIRT1 inhibitors (EX-527, cambinol, tenovin-6) induced dose-dependent cytotoxicity in DLBCL cell lines, while simultaneous addition of HSP90 inhibitor (17AAG) produced synergistic or additive effect in OxPhos-, but not BCR-DLBCLs. Taken together, our findings define a new OxPhos DLBCL-specific pathogenetic mechanism involving SIRT1 and HSP90alpha that regulates chromosome dynamics during mitosis and may be exploited therapeutically. Disclosures Juszczynski: Ryvu Therapeutics: Other: member of advisory board.

Functional Link Between Heat Shock Protein HSP90alpha and Sirtuin 1 (SIRT1) in the Pathogenesis of Diffuse Large B Cell Lymphoma

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4120-4120
Author(s):  
Emilia Bialopiotrowicz ◽  
Tomasz Sewastianik ◽  
Monika Noyszewska-Kania ◽  
Maciej Szydlowski ◽  
Ewa Jablonska ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
B Cell ◽  
Cell Lines ◽  
Feedback Loop ◽  
B Cell Lymphoma ◽  
Synergistic Activity ◽  
Sirt1 Inhibitor ◽  
Interfering Rna ◽  
Large B Cell

Abstract Diffuse large B-cell lymphomas (DLBCL) are heterogenous tumors. A large subset of DLBCL is reliant on B-cell receptor activity ('BCR'-DLBCLs). Additional subset of tumors that does not exhibit addiction to BCR signaling features transcriptional program is associated with increased oxidative phosphorylation ('OxPhos'-DLBCLs, Blood 2005; 105: 1851-61). These OxPhos tumros are resistant to BCR inhibition and remain functionally poorly defined. We and others found that OxPhos-DLBCLs, compared to BCR subtype, exhibit overexpression of heat shock protein HSP90alpha (Br J Haematol 2009; 144: 358-66). Expression of multiple heat shock proteins is regulated by the activity of a stress-responsive, acetylation-dependent transcription factor HSF1. Acetylation blocks, whereas deacetylation by sirtuins increases HSF1 activity. However, molecular mechanisms responsible for increased HSP90alpha expression in OxPhos-DLBCLs remain unknown. We investigated the abundance of NAD-dependent deacetylase SIRT1 in a panel of DLBCL cell lines and found that SIRT1 protein level was higher in OxPhos- than BCR-DLBCLs and correlated positively with HSP90alpha gene expression (p=0.02, r=0.7857). To assess the role of SIRT1 in transcriptional regulation of HSP90alpha, we used a small molecule SIRT1 inhibitor tenovin-6 or interfering RNA, which dramatically reduced HSP90alpha induction after heat shock. We next characterized the mechanisms of SIRT1 overexpression in OxPhos cells. SIRT1 transcript abundance was similar in OxPhos and BCR cells, suggesting that changes in SIRT1 expression result from different protein half-life/stability. To test this assumption, OxPhos and BCR cells were incubated with a protein synthesis inhibitor, cycloheximide, and assessed for SIRT1 protein decays over time. Our experiments revealed increased stability of SIRT1 protein in OxPhos-DLBCLs, compared to BCR-DLBCLs. Addition of an HSP90 inhibitor 17-AAG accelerated SIRT1 protein degradation, suggesting that HSP90 might chaperone and thus protect SIRT1 against degradation. We further found that SIRT1 coimmunoprecipitated with HSP90alpha, confirming interaction between these proteins and highlighting a self-reinforcing feedback loop linking HSP90alpha and SIRT1 in OxPhos-DLBCLs. We next assessed the therapeutic potential of SIRT1 inhibition in DLBCLs. SIRT1 knockdown with small interfering RNA or chemical SIRT1 inhibition (tenovin-6) decreased proliferation of OxPhos-DLBCL cells, but also of BCR-DLBCLs, indicating that SIRT1 inhibition exhibits broader, subtype-independent activity in DLBCL cell lines. Surprisingly, BCR-type DLBCLs were significantly more sensitive to SIRT1 inhibitor, tenovin-6. We thus sought to identify a mechanism responsible for SIRT1 inhibition in BCR-DLBCLs. Since SIRT1 deacetylase modulates the transcriptional activity of BCL6 oncogene, critical for survival of BCR-type DLBCLs (PNAS 2007; 104: 3207-12), we assessed the expression of BCL6-regulated genes in these cells. SIRT1 inhibition upregulated the abundance of multiple BCL6-dependent transcripts (including FCER2, CCL3, BLIMP1 and CD74), suggesting that toxicity of SIRT1 inhibition in BCL6-dependent DLBCLs is, at least partially, mediated by decreased BCL6 repressor activity. Although OxPhos-DLBCLs were less sensitive to tenovin-6 than BCR-type DLBCLs, we hypothesized that, given the feedback loop between SIRT1 and HSP90, simultaneous inhibition of HSP90 would increase the cellular sensitivity to tenovin-6. Consistent with this, we found that combination of these two compounds exhibited synergistic activity in OxPhos-DLBCL. Taken together, our data demonstrate that SIRT1 and HSP90alpha are mutually linked and involved in the pathogenesis of OxPhos-DLBCL. Targeting SIRT1-HSP90alpha loop with combinatorial use of SIRT1 and HSP90 inhibitors might be a promising treatment strategy in OxPhos-DLBCLs. Disclosures Warzocha: BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Juszczynski:Selvita S.A.: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Antitumor Efficacy of the Purine-Scaffold Hsp90 Inhibitor PU-H71 in Diffuse Large-B Cell Lymphoma

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 602-602
Author(s):  
Eloisi Caldas Lopes ◽  
Leandro Cerchietti ◽  
Shao Ning Yang ◽  
Ari Melnick ◽  
Gabriela Chiosis
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Hsp90 Inhibitor ◽  
Hsp90 Inhibitors ◽  
Hsp90 Inhibition ◽  
Normal Tissues ◽  
Large B Cell Lymphoma ◽  
Large B Cell

Abstract Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma. Although many DLBCLs are responsive to CD20 antibody/chemotherapy regimens, a significant proportion of patients will still die of their disease. It is possible that targeting important lymphomagenic pathways could improve the potency and reduce the toxicity of future lymphoma therapy. One of the challenges of harnessing molecular targets for the therapy of DLBCL is the remarkable genetic and molecular heterogeneity of this disease. Along these lines, we found that Hsp90 is expressed in more than 90% of patients with DLBCL. Taken together with the fact that Hsp90 is a crucial component of a wide range of signaling processes that are important for cancer cell survival, we hypothesized that Hsp90 inhibition could be an effective strategy for heterogeneous tumors with multiple pathway aberrations such as DLBCL. However, the clinical translation of the available benzoquinone Hsp90 inhibitors has been challenged by their liver toxicity. We developed a non-quinone Hsp90 inhibitor PU-H71 with potent activity in pre-clinical models of DLBCL. When screened against a panel of 32 DLBCL cell lines, PU-H71 was among the most active drugs even compared to classical chemotherapy and new targeted drugs. Inhibition of Hsp90 by PU-H71 in DLBCL (OCI-Ly7, Farage and SUDHL4 cell lines) resulted in significant activation of apoptosis, as observed morphologically and biochemically by detecting the activation of caspase-3, 7 and the cleavage of PARP. Hsp90 inhibition by PU-H71 in DLBCL was associated with the destabilization and subsequent degradation of several onco-proteins such as Akt, c-Raf and IKK/Nemo, thus affecting the activity of many oncogenic pathways. To evaluate the in vivo anti-lymphoma effect of PU-H71, OCI-Ly7, Farage and SUDHL4 xenografted tumors were established in SCID mice. Mice received either 75mg/kg/day of PU-H71 or vehicle (water) (n=5 per treatment and per cell line). By day 10, the tumors in the PU-H71 treated mice were significantly smaller in volume than their respective controls, with 76%, 95% and 95% inhibition of tumor growth observed in Farage, OCI-Ly7 and SUDHL4 mice, respectively (p=0.002, p<0.0001and p=0.0002, respectively). The tumor weight at day 10 was also reduced by PU-H71, as were the serum levels of the DLBCL surrogate marker human B-2-microglobulin. There was also a significant increase in the survival time of the PU-H71 treated mice (n=15) compared to the control treated mice (n=15) (Kaplan-Meier survival curve, Cox’s F test p<0.0001). No toxicity was observed during treatment as evidenced by a lack of significant change in animal weight, fur appearance, appetite and posture. Furthermore, no visible internal organ damage was detected at sacrifice upon gross inspection and histological examination. Additional toxicity studies in normal mice which also included biochemical panels and CBC, confirmed these results. There were no abnormalities in liver enzymes levels nor was the appearance of gastrointestinal mucositis observed in PU-H71 treated mice, in contrast to previous reports with the benzoquinone Hsp90 inhibitors, 17-AAG and 17-DMAG. The serum and tissues of Farage xenografts were analyzed for PU-H71 concentration by HPLC-MS. Pharmacologically relevant doses of PUH71 were found retained in tumors even at 24 h post-administration (42.1 ug/g at 6 h, 27.6 ug/g at 12 h and 12 ug/g at 24 h). In contrast, the levels of PU-H71 in normal tissues rapidily dropped at 12 h post administration and were at all-times bellow the level reached in tumors (at 12 h the tumor concentration of PU-H71 was between 11.2 and 125.6 times higher than in normal tissues). This indicates that PU-H71 is preferentially retained in DLBCL compared to normal tissues, partly explaining the lack of toxicity observed at highly efficient therapeutic doses of PU-H71. Its preferential tumor retention could also be observed by PET in living animals using a radiolabeled PU-H71. Due to its potent anti-tumor activity and favorable toxicity profile, PU-H71 is undergoing late-stage IND evaluation and is scheduled to enter Phase I clinical evaluation in patients with lymphomas in 2009.

Anti-Apoptotic Bcl2 and Bcl-Xl Proteins Involved in Stroma-Induced Drug Tolerance to Hsp70 and Hsp90 Inhibitors in Leukemia and B-Cell Lymphoma

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4900-4900
Author(s):  
Eloisi Caldas Lopes ◽  
Fabian M Correa ◽  
Ling-Bo Shen ◽  
Jae-Hung Shieh ◽  
Tony Taldone ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Stromal Cells ◽  
Stromal Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Hsp90 Inhibitor ◽  
Large B Cell Lymphoma ◽  
Induced Apoptosis ◽  
Large B Cell

Abstract Abstract 4900 Background: Multiple studies have demonstrated that the bone marrow stromal microenvironment contributes to the survival of hematologic malignant cells, eventually leading to relapse. However, molecular mechanisms associated with this stromal niche remain unclear. The human bone marrow stromal cell lines, HS-5 and HS-27, provide physical contact with hematologic cells, while HS-5 cells secrete more growth factors and cytokines than HS-27 stromal cells. Our objective is to dissect the mechanisms underlying stromal-mediated drug tolerance in leukemia and lymphoma cells, which could potentially lead to novel therapies for various leukemia. Methods and Results: A panel of leukemia and B-cell lymphoma cell lines were used in this project, including Kasumi1 (AML: Acute Myeloid Leukemia) and OCILy1 (DLBCL: Diffuse Large B-Cell Lymphoma) cells and their respective sub-lines resistant to heat shock protein-70 and −90 (HSP70/90) inhibitors. To determine the ability of stromal cell lines to confer tolerance to HSP-inhibitors, Kasumi1 and OCILy1 (sensitive and resistant) cells were cultured alone or in the presence of the HS-27 or HS-5 cells with HSP70 inhibitor or HSP90 inhibitor for 48h. The resulting cultures were then harvested and analyzed for apoptosis and by western blot. Both HS-5 and HS-27 stromal cells markedly protected OCILy1 and Kasumi1 cells from HSP70 inhibitor induced apoptosis. At a dose of 0.5 μM, % apoptotic cells were 74.0±1.6% for OCILy1 alone, 38.3±2.1% for OCILy1 with HS-5 and 42.2±1.8% for OCILY1 with HS-27. At a dose of 1 μM of HSP90 inhibitor, apoptosis rate are 61.9±1.5% for OCILy1 alone, 28.2±2.2% for OCILy1 with HS-5 and 36.4±1.9% for OCILy1 with HS-27. A similar HSP inhibitor induced apoptosis was also observed in Kasumi1 cells. In contrast, both Kasumi1 and OCILy1 HSP70/90 inhibitor resistant sub-lines in the presence or absence of the stromal cells did not respond to treatment with respective inhibitors. Further study reveals the stromal cells up-modulated the expression of the anti-apoptotic proteins Bcl2 and Bcl-xL in both Kasumi and OCILY1 cells. Conclusions: Our results demonstrate that the stromal niche is able to mediate tolerance to HSP70 and HSP90 inhibitors in Leukemia and B-cell lymphoma via up-regulation of antiapoptotic proteins such as Bcl2 and Bcl-xL. The Bcl2 protein is deregulated and plays a crucial role in diffuse large B-cell lymphoma (DLBCL) with the t(14;18) translocation. Our finding elucidates one of the drug-specific mechanisms that suggest a promising combination therapy targeting both HSP70 and HSP90 to reduce antineoplastic resistance and relapse, and thereby improve survival for patients with leukemia and lymphoma. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Epiligrin, a component of epithelial basement membranes, is an adhesive ligand for alpha 3 beta 1 positive T lymphocytes.

1993 ◽  
Vol 121 (5) ◽  
pp. 1141-1152 ◽  
Author(s):  
E A Wayner ◽  
S G Gil ◽  
G F Murphy ◽  
M S Wilke ◽  
W G Carter
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Basement Membrane ◽  
B Cell ◽  
Cell Lines ◽  
B Cell Lymphoma ◽  
Lymphokine Activated Killer Cells ◽  
Cutaneous Inflammation ◽  
Epidermal Basement Membrane

The cutaneous T cell lymphomas (CTCL), typified by mycosis fungoides, and several chronic T cell mediated dermatoses are characterized by the migration of T lymphocytes into the epidermis (epidermotropism). Alternatively, other types of cutaneous inflammation (malignant cutaneous B cell lymphoma, CBCL, or lymphocytoma cutis, non-malignant T or B cell type) do not show evidence of epidermotropism. This suggests that certain T lymphocyte subpopulations are able to interact with and penetrate the epidermal basement membrane. We show here that T lymphocytes derived from patients with CTCL (HUT 78 or HUT 102 cells), adhere to the detergent-insoluble extracellular matrix prepared from cultured basal keratinocytes (HFK ECM). HUT cell adhesion to HFK ECM was inhibitable with monoclonal antibodies (mAbs) directed to the alpha 3 (P1B5) or beta 1 (P4C10) integrin receptors, and could be up-regulated by an activating anti-beta 1 mAb (P4G11). An inhibitory mAb, P3H9-2, raised against keratinocytes identified epiligrin as the ligand for alpha 3 beta 1 positive T cells in HFK ECM. Interestingly, two lymphocyte populations could be clearly distinguished relative to expression of alpha 3 beta 1 by flow cytometry analysis. Lymphokine activated killer cells, alloreactive cytotoxic T cells and T cells derived from patients with CTCL expressed high levels of alpha 3 beta 1 (alpha 3 beta 1high). Non-adherent peripheral blood mononuclear cells, acute T or B lymphocytic leukemias, or non-cutaneous T or B lymphocyte cell lines expressed low levels of alpha 3 beta 1 (alpha 3 beta 1low). Resting PBL or alpha 3 beta 1low T or B cell lines did not adhere to HFK ECM or purified epiligrin. However, adhesion to epiligrin could be up-regulated by mAbs which activate the beta 1 subunit indicating that alpha 3 beta 1 activity is a function of expression and affinity. In skin derived from patients with graft-vs.-host (GVH) disease, experimentally induced delayed hypersensitivity reactions, and CTCL, the infiltrating T cells could be stained with mAbs to alpha 3 or beta 1 and were localized in close proximity to the epiligrin-containing basement membrane. Infiltrating lymphocytes in malignant cutaneous B disease (CBCL) did not express alpha 3 beta 1 by immunohistochemical techniques and did not associate with the epidermal basement membrane. The present findings clearly define a function for alpha 3 beta 1 in T cells and strongly suggest that alpha 3 beta 1 interaction with epiligrin may be involved in the pathogenesis of cutaneous inflammation.

scholarly journals MicroRNA-181a Inhibits Activated B-Cell-Like Diffuse Large B-Cell Lymphoma Progression by Repressing CARD11

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Danxia Zhu ◽  
Cheng Fang ◽  
Wenting He ◽  
Chen Wu ◽  
Xiaodong Li ◽  
...  
Keyword(s):  
B Cell ◽  
Binding Site ◽  
Cell Lines ◽  
Expression Vector ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Wild Type ◽  
Protein Levels ◽  
Large B Cell Lymphoma ◽  
Large B Cell

We investigated the role of miR-181a in diffuse large B-cell lymphoma (DLBCL) and its potential target genes. miR-181a levels were lower in activated B-cell- (ABC-) like DLBCL cells than that in germinal center B-cell- (GCB-) like DLBCL cells. Overexpression of miR-181a in ABC-like DLBCL cell lines (OCI-LY10 and U2932) resulted in G0/G1 cell cycle arrest, increased apoptosis, and decreased invasiveness. miRNA target prediction programs (miRanda, TargetScan, and miRDB) identified caspase recruitment domain-containing protein 11 (CARD11) as a putative miR-181a target. CARD11 mRNA and protein levels were higher in the ABC-like DLBCL than that in GCB-like DLBCL. Moreover, CARD11 mRNA and protein levels were downregulated in the OCI-LY10 and U2932 cell lines overexpressing miR-181a. Dual luciferase reporter assays confirmed the miR-181a binding site in the CARD11 3′UTR region. OCI-LY10 and U2932 cells transfected with a CARD11 expression vector encoding miR-181a with a mutated binding site showed higher CARD11 protein levels, cell viability, G2/M phase cells, and invasiveness compared to those transfected with a wild-type CARD11 expression vector. Nude mice xenografted with OCI-LY10 cells with overexpressed wild-type miR-181a generated smaller tumors compared to those with overexpressed mutated binding site of CARD11 3′UTR and miR-181a. These results indicate that miR-181a inhibits ABC-like DLBCL by repressing CARD11.

Characterization of two new high-grade B-cell lymphoma cell lines with MYC and BCL2 rearrangements that are suitable for in vitro drug sensitivity studies

2018 ◽  
Vol 60 (4) ◽  
pp. 1043-1052
Author(s):  
Marie-Sophie Dheur ◽  
Hélène A. Poirel ◽  
Geneviève Ameye ◽  
Gaëlle Tilman ◽  
Pascale Saussoy ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Drug Sensitivity ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Lymphoma Cell ◽  
High Grade ◽  
Sensitivity Studies

scholarly journals Targeting ubiquitin-activating enzyme induces ER stress–mediated apoptosis in B-cell lymphoma cells

2019 ◽  
Vol 3 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Scott Best ◽  
Taylor Hashiguchi ◽  
Adam Kittai ◽  
Nur Bruss ◽  
Cody Paiva ◽  
...  
Keyword(s):  
Er Stress ◽  
B Cell ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Proteasome Inhibitors ◽  
B Cell Lymphoma ◽  
Proteasome Inhibition ◽  
Cell Of Origin ◽  
Protein Ubiquitination

Abstract Alterations in the ubiquitin proteasome system (UPS) leave malignant cells in heightened cellular stress, making them susceptible to proteasome inhibition. However, given the limited efficacy of proteasome inhibitors in non-Hodgkin lymphoma (NHL), novel approaches to target the UPS are needed. Here, we show that TAK-243, the first small-molecule inhibitor of the ubiquitin activating enzyme (UAE) to enter clinical development, disrupts all ubiquitin signaling and global protein ubiquitination in diffuse large B-cell lymphoma (DLBCL) cells, thereby inducing endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). Activation of the ER stress response protein kinase R (PKR)–like ER kinase and phosphorylation of eukaryotic translation initiator factor 2α led to upregulation of the proapoptotic molecule C/EBP homologous protein and cell death across a panel of DLBCL cell lines independent of cell of origin. Concurrently, targeting UAE led to accumulation of Cdt1, a replication licensing factor, leading to DNA rereplication, checkpoint activation, and cell cycle arrest. MYC oncoprotein sensitized DLBCL cells to UAE inhibition; engineered expression of MYC enhanced while genetic MYC knockdown protected from TAK-243–induced apoptosis. UAE inhibition demonstrated enhanced ER stress and UPR and increased potency compared with bortezomib in DLBCL cell lines. In vivo treatment with TAK-243 restricted the growth of xenografted DLBCL tumors, accompanied by reduced cell proliferation and apoptosis. Finally, primary patient-derived DLBCL cells, including those expressing aberrant MYC, demonstrated susceptibility to UAE inhibition. In sum, targeting UAE may hold promise as a novel therapeutic approach in NHL.

scholarly journals Repurposing dasatinib for diffuse large B cell lymphoma

2019 ◽  
Vol 116 (34) ◽  
pp. 16981-16986 ◽  
Author(s):  
Claudio Scuoppo ◽  
Jiguang Wang ◽  
Mirjana Persaud ◽  
Sandeep K. Mittan ◽  
Katia Basso ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Kinase Inhibitor ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Multikinase Inhibitor ◽  
Large B Cell Lymphoma ◽  
Large B Cell

To repurpose compounds for diffuse large B cell lymphoma (DLBCL), we screened a library of drugs and other targeted compounds approved by the US Food and Drug Administration on 9 cell lines and validated the results on a panel of 32 genetically characterized DLBCL cell lines. Dasatinib, a multikinase inhibitor, was effective against 50% of DLBCL cell lines, as well as against in vivo xenografts. Dasatinib was more broadly active than the Bruton kinase inhibitor ibrutinib and overcame ibrutinib resistance. Tumors exhibiting dasatinib resistance were commonly characterized by activation of the PI3K pathway and loss of PTEN expression as a specific biomarker. PI3K suppression by mTORC2 inhibition synergized with dasatinib and abolished resistance in vitro and in vivo. These results provide a proof of concept for the repurposing approach in DLBCL, and point to dasatinib as an attractive strategy for further clinical development in lymphomas.

scholarly journals Establishment of two Epstein-Barr virus negative Burkitt cell lines from a patient with AIDS and B-cell lymphoma

Blood ◽  
1988 ◽  
Vol 72 (4) ◽  
pp. 1255-1260 ◽  
Author(s):  
A Ganser ◽  
C Carlo-Stella ◽  
CR Bartram ◽  
T Boehm ◽  
G Heil ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Epstein Barr Virus ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Cell Receptor ◽  
Immunoglobulin Gene ◽  
Barr Virus ◽  
Epstein Barr ◽  
Immunodeficiency Syndrome

Abstract To analyze the pathogenesis of B-cell lymphomas in patients with acquired immunodeficiency syndrome (AIDS), we studied two cell lines, Es I and Es III, established from one such lymphoma for the presence of sequences of the Epstein-Barr virus (EBV) and the human immunodeficiency virus [HIV; lymphadenopathy-associated virus (LAV/HTLV- III)] as well as for the presence of cytogenetic abnormalities and monoclonal rearrangements of immunoglobulin and T-cell receptor genes. Both cell lines expressed the same IgM, kappa phenotype as the original lymphoma. The karyotype of Es I was 46, XY, t(8;14), 2 p+, inv (6p), 17p-, and the cells of Es III had an additional i(7q). Immunoglobulin gene studies demonstrated the identical monoclonal rearrangements in both cell lines. Neither EBV nor HIV sequences were detectable in the malignant B cells at the genomic level, leading to the conclusion that mechanisms other than transformation by EBV or HIV may have contributed to the B-cell lymphoma in this patient and possibly also to the generally increased frequency in patients with AIDS.

Sign in / Sign up

Export Citation Format

Share Document