scholarly journals Targetable genetic alterations of TCF4 (E2-2) drive immunoglobulin expression in the activated B-cell subtype of diffuse large B-cell lymphoma

2017 ◽  
Author(s):  
Neeraj Jain ◽  
Keenan Hartert ◽  
Saber Tadros ◽  
Warren Fiskus ◽  
Ondrej Havranek ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Genetic Alterations ◽  
Immunoglobulin Gene ◽  
Large B Cell Lymphoma ◽  
Bet Inhibitors ◽  
Large B Cell

ABSTRACTThe activated B-cell (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) is characterized by the chronic activation of signaling initiated by immunoglobulin-μ (IgM). By analyzing DNA copy profiles of 1,000 DLBCLs, we identified gains of 18q21.2 as the most frequent genetic alteration in ABC-like DLBCL. We show that these alterations target the TCF4 (E2-2) transcription factor, and that over-expression of TCF4 leads to its occupancy on immunoglobulin gene enhancers and increased expression of IgM at the transcript and protein level. The TCF4 gene is one of the top BRD4-regulated genes in DLBCL. Using a BET proteolysis-targeting chimera (PROTAC) we show that TCF4 and IgM expression can be extinguished, and ABC-like DLBCL cells can be killed in vitro and in vivo. This highlights a novel genetic mechanism for promoting immunoglobulin signaling in ABC-like DLBCL and provides a functional rationale for the use of BET inhibitors in this disease.

Novel cyclophosphamide of natural products osalmide and pterostilbene induces cytotoxicity and cell cycle arrest in diffuse large B-cell lymphoma cells

2020 ◽  
Vol 52 (4) ◽  
pp. 401-410
Author(s):  
Mengyu Xi ◽  
Wan He ◽  
Bo Li ◽  
Jinfeng Zhou ◽  
Zhijian Xu ◽  
...  
Keyword(s):  
Natural Products ◽  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Underlying Mechanism ◽  
Anticancer Activities ◽  
Large B Cell Lymphoma ◽  
Large B Cell

Abstract Diffuse large B-cell lymphoma (DLBCL) is the most common category and disease entity of non-Hodgkin lymphoma. Osalmide and pterostilbene are natural products with anticancer activities via different mechanism. In this study, using a new synthetic strategy for the two natural products, we obtained the compound DCZ0801, which was previously found to have anti-multiple myeloma activity. We performed both in vitro and in vivo assays to investigate its bioactivity and explore its underlying mechanism against DLBCL cells. The results showed that DCZ0801 treatment gave rise to a dose- and time-dependent inhibition of cell viability as determined by CCK-8 assay and flow cytometry assay. Western blot analysis results showed that the expression of caspase-3, caspase-8, caspase-9 and Bax was increased, while BCL-2 and BCL-XL levels were decreased, which suggested that DCZ0801 inhibited cell proliferation and promoted intrinsic apoptosis. In addition, DCZ0801 induced G0/G1 phase arrest by downregulating the protein expression levels of CDK4, CDK6 and cyclin D1. Furthermore, DCZ0801 exerted an anti-tumor effect by down-regulating the expressions of p-PI3K and p-AKT. There also existed a trend that the expression of p-JNK and p-P38 was restrained. Intraperitoneal injection of DCZ0801 suppressed tumor development in xenograft mouse models. The preliminary metabolic study showed that DCZ0801 displayed a rapid metabolism within 30 min. These results demonstrated that DCZ0801 may be a new potential anti-DLBCL agent in DLBCL therapy.

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.

Loss of IRF8 Inhibits the Growth of Diffuse Large B-Cell Lymphoma

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3004-3004
Author(s):  
Yulian Xu ◽  
Lei Jiang ◽  
Rachel R. Fang ◽  
Jeff Xiwu Zhou ◽  
Herbert Morse
Keyword(s):  
Cell Proliferation ◽  
B Cell ◽  
Cell Lymphoma ◽  
Critical Role ◽  
B Cell Lymphoma ◽  
Expression Levels ◽  
Large B Cell Lymphoma ◽  
Large B Cell

Abstract IRF8 is a transcription factor with a critical role in B lymphocyte development and biological functions. Although it has been reported that IRF8 is highly expressed in human diffuse large B-cell lymphoma (DLBCL) and the translocation of IRF8-IgH loci occurs in DLBCL, little information is available regarding the function and mechanisms for the role of IRF8 in DLBCL. In this study, by using several human DLBCL cell lines with shRNA-mediated decrease in IRF8 expression levels, we found that the loss of IRF8 significantly reduced the proliferation of lymphoma cells (Figure 1). Mechanistically, decreasing the levels of IRF8 led to a decrease in p38 and ERK phosphorylation (Figure 2), molecular events critical for B cell proliferation. Furthermore, using a xenograft lymphoma mice model, we found that the loss of IRF8 significantly inhibited the growth of lymphomas in vivo (n=5 for each group) (Figure 3). Analysis of public available data also suggested that the expression levels of IRF8 mRNA in human DLBCL tissues were inversely correlated patientsÕ overall survival time. Taken together, this study showed that IRF8 may play an oncogenic role in human DLBCL by promoting cell proliferation. Figure 1. Loss of IRF8 decreased the proliferation of DLBCL cells in vitro. Figure 1. Loss of IRF8 decreased the proliferation of DLBCL cells in vitro. Figure 2. Loss of IRF8 decreased the phosphorylation of p38 and ERK in DLBCL cells. Figure 2. Loss of IRF8 decreased the phosphorylation of p38 and ERK in DLBCL cells. Figure 3. Loss of IRF8 decreased the growth of DLBCL in vivo. Figure 3. Loss of IRF8 decreased the growth of DLBCL in vivo. Disclosures No relevant conflicts of interest to declare.

scholarly journals Targeting Positive Cofactor 4 induces autophagic cell death in MYC-expressing diffuse large B cell lymphoma

2021 ◽  
Author(s):  
Le Ma ◽  
Qiang Gong ◽  
Zelin Chen ◽  
Yu Wang ◽  
Xu Tan ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cell ◽  
Molecular Mechanisms ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Autophagic Cell Death ◽  
Large B Cell Lymphoma ◽  
Large B Cell

Abstract Background: The MYC-expressing diffuse large B-cell lymphoma (DLBCL) is one of the refractory lymphomas. The pathogenesis of MYC-expressing DLBCL is still unclear, and there is a lack of effective therapy. In this study, we have explored the clinical significance and the molecular mechanisms of transcription co-activator 4 (PC4) in MYC-expressing DLBCL.Methods: We investigated PC4 expression in 54 cases of DLBCL patients’ tissues and matched normal specimens, and studied the molecular mechanisms of PC4 in MYC-expressing DLBCL both in vitro and in vivo.Results: We reported for the first time that targeting c-Myc could induce autophagic cell death in MYC-expressing DLBCL cell lines. We next characterized that PC4 was an upstream regulator of c-Myc, and PC4 was overexpressed in DLBCL and was closely related to clinical staging, prognosis and c-Myc expression. Further, our in vivo and in vitro studies revealed that PC4 knockdown could induce autophagic cell death of MYC-expressing DLBCL. And inhibition of c-Myc mediated aerobic glycolysis and activation of AMPK / mTOR signaling pathway were responsible for the autophagic cell death induced by PC4 knockdown in MYC-expressing DLBCL. Through the CHIP, DLRTM and EMSA assay, we also found that PC4 exerted its oncogenic functions by directly binding to c-Myc promoters.Conclusions: PC4 exerts its oncogenic functions by directly binding to c-Myc promoters. Inhibition of PC4 can induce autophagic cell death of MYC-expressing DLBCL. Our study provides novel insights into the functions and mechanisms of PC4 in MYC-expressing DLBCL, and suggests that PC4 might be a promising therapeutic target for MYC-expressing DLBCL.

scholarly journals Circulating Exosomal MiR-107 Restrains Tumorigenesis in Diffuse Large B-Cell Lymphoma by Targeting 14-3-3η

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiarui Liu ◽  
Yang Han ◽  
Shunfeng Hu ◽  
Yiqing Cai ◽  
Juan Yang ◽  
...  
Keyword(s):  
B Cell ◽  
Target Genes ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Prognostic Indicator ◽  
Diagnostic Value ◽  
Large B Cell Lymphoma ◽  
Large B Cell

Exosomes, nanometer-sized membranous vesicles in body fluids, have emerged as promising non-invasive biomarkers for cancer diagnosis. However, the function of exosomes in diffuse large B-cell lymphoma (DLBCL) remains elusive. This study aimed to investigate the role of exosomal miR-107 in lymphomagenesis and explore its clinical significance. In this study, decreased exosomal miR-107, miR-375-3p, and upregulated exosomal miR-485-3p were detected in the plasma of DLBCL patients and showed potential diagnostic value. Downregulated miR-107 expression was associated with advanced Ann Arbor stage, high IPI score, LDH, and β2-MG level in DLBCL patients. Overexpression of miR-107 by miR-107 Agomir significantly abrogated cell proliferation, induced apoptosis, and inhibited cell invasion in vitro, and repressed tumor growth in vivo. Moreover, the downregulation of miR-107 went in the opposite direction. The target genes of miR-107 were mainly enriched in the PI3K-Akt, Hippo, and AMPK signaling pathways. Notably, upregulated 14-3-3η (YWHAH) was suppressed by miR-107 in DLBCL, suggesting that miR-107 may restrain tumorigenesis by targeting 14-3-3η. In summary, this study unveils the function of miR-107 in lymphomagenesis, highlighting its potential as a diagnostic and prognostic indicator and as a new therapeutic target in the management of DLBCL.

scholarly journals The bromodomain and extra-terminal domain degrader MZ1 exhibits preclinical anti-tumoral activity in diffuse large B-cell lymphoma of the activated B cell-like type

2021 ◽  
Vol 2 (6) ◽  
pp. 586-601
Author(s):  
Chiara Tarantelli ◽  
Eleonora Cannas ◽  
Hillarie Ekeh ◽  
Carmelo Moscatello ◽  
Eugenio Gaudio ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Bet Inhibitor ◽  
Terminal Domain ◽  
Large B Cell Lymphoma ◽  
Bet Inhibitors ◽  
Large B Cell

Aim: Bromodomain and extra-terminal domain (BET) proteins are epigenetic readers that play a fundamental role in transcription regulation. Preclinical and early clinical evidence sustain BET targeting as an anti-cancer approach. BET degraders are chimeric compounds comprising of a BET inhibitor, which allows the binding to BET bromodomains, linked to a small molecule, binder for an E3 ubiquitin ligase complex, triggering BET proteins degradation via the proteasome. These degraders, called proteolysis-targeting chimeras (PROTACs), can exhibit greater target specificity compared to BET inhibitors and overcome some of their limitations, such as the upregulation of the BET proteins themselves. Here are presented data on the anti-tumor activity and the mechanism of action of the BET degrader MZ1 in diffuse large B cell lymphoma (DLBCL) of the activated B-cell like (ABC, ABC DLBCL), using a BET inhibitor as a comparison. Methods: Established lymphoma cell lines were exposed for 72 h to increasing doses of the compounds. Cell proliferation was evaluated by using an 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazoliumbromide (MTT) assay. Fluorescent-Activated Cell Sorter (FACS) analysis was performed to measure apoptotic activation and RNA sequencing (RNA-Seq) to study the transcriptional changes induced by the compounds. Results: MZ1, and not its negative control epimer cisMZ1, was very active with a median half maximal inhibitory concentration (IC50) of 49 nmol/L. MZ1 was more in vitro active than the BET inhibitor birabresib (OTX015). Importantly, MZ1 induced cell death in all the ABC DLBCL cell lines, while the BET inhibitor was cytotoxic only in a fraction of them. BET degrader and inhibitor shared partially similar changes at transcriptome level but the MZ1 effect was stronger and overlapped with that caused cyclin-dependent kinase 9 (CDK9) inhibition. Conclusions: The BET degrader MZ1 had strong cytotoxic activity in all the ABC DLBCL cell lines that were tested, and, at least in vitro, it elicited more profound effects than BET inhibitors, and encourages further investigations.

scholarly journals MYC-Dependent PI3K and MCL-1 Feedbacks Attenuate BET Inhibitors Activity in Diffuse Large B-Cell Lymphoma

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 294-294
Author(s):  
Enrico Derenzini ◽  
Patrizia Mondello ◽  
Yuxuan Liu ◽  
Mary Scallion ◽  
Zahra Asgari ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Pi3k Pathway ◽  
Combination Strategies ◽  
Large B Cell Lymphoma ◽  
Bet Inhibitors ◽  
Large B Cell

Abstract MYC overexpression is a poor prognostic predictor in Diffuse Large B-Cell Lymphoma (DLBCL). MYC-targeting with bromodomain and extraterminal protein family (BET) inhibitors is a promising strategy for the treatment of MYC-driven cancers, including lymphomas. However, preclinical and emerging data from early clinical trials demonstrated a modest antiproliferative activity in vitro and in vivo. We hypothesized that BET inhibition may induce feedback survival mechanisms preventing or attenuating cell death that could be exploited for designing future, more effective, combination strategies. In a high-throughput combinatorial drug screening experiment, we found that phosphatidylinositol 3-kinase (PI3K) pathway inhibitors enhanced the antiproliferative effects of BET inhibitors (JQ1, I-BET 151, CPI-203) with a strong class effect. JQ1 upregulated the mRNA expression of several upstream components of the PI3K pathway, including PIK3CA, PIK3R1, PDK1 in a large panel of DLBCL and Burkitt lymphoma cell lines. These effects translated in increased pathway activation as demonstrated by increased levels of the phosphorylated forms of downstream targets GSK3α/β, TSC2, P70S6K, and by increased concentrations of chemokines known to be regulated by PI3K in cell culture supernatants (CCL3 and CCL4). This effect was reversed by submicromolar doses of the PI3K inhibitor BKM-120. MYC silencing recapitulated the effects of BET inhibitors on PI3K pathway gene expression, activation and chemokine secretion. These data indicate that BET inhibition induces PI3K activation by a MYC-dependent feedback. We also observed transcriptional upregulation of the antiapoptotic gene Myeloid Leukemia 1 (MCL-1) following BET inhibition or MYC depletion, suggesting a second MYC-dependent mechanism. RNAi-mediated MCL-1 silencing or co-treatment with a small molecule MCL-1 inhibitor (UMI-77) enhanced the effects of BET inhibitors in DLBCL cell lines by inducing apoptosis. Using SILAC-based quantitative mass spectrometry, we found that BET inhibitors at submicromolar doses downregulated several E2 ubiquitin conjugating enzymes including UBE2C. RNAi mediated UBE2C knockdown induced MCL-1 upregulation in DLBCL cells. The enhanced in vitro effect of combining BETi and PI3Ki was reproduced in TMD8 mouse xenografts. To our knowledge, this is the first study demonstrating MYC-dependent regulation of the PI3K pathway, MCL-1 and the ubiquitin system upon BET inhibition. Our study revealed previously unknown mechanisms of action of BET inhibitors uncovering novel MYC-dependent survival feedback loops, and providing a framework for future combination strategies. Disclosures Zelenetz: Gilead Sciences: Research Funding.

scholarly journals The Synergistic Anti-Tumor Activity of EZH2 Inhibitor SHR2554 and HDAC Inhibitor Chidamide through ORC1 Reduction of DNA Replication Process in Diffuse Large B Cell Lymphoma

Cancers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 4249
Author(s):  
Xing Wang ◽  
Dedao Wang ◽  
Ning Ding ◽  
Lan Mi ◽  
Hui Yu ◽  
...  
Keyword(s):  
B Cell ◽  
Hdac Inhibitor ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Replication Process ◽  
Large B Cell Lymphoma ◽  
Anti Tumor Activity ◽  
Large B Cell

Background: Upregulation of H3K27me3 induced by EZH2 overexpression or somatic heterozygous mutations were implicated in lymphomagenesis. It has been demonstrated that several EZH2-target agents have notable therapeutic effects in EZH2-mutant B-cell lymphoma patients. Here we present a novel highly selective EZH2 inhibitor SHR2554 and possible combination strategy in diffuse large B-cell lymphoma (DLBCL). Methods: Cell proliferation, cell cycle and apoptosis were analyzed by CellTiter-Glo Luminescent Cell Viability Assay and flow cytometry. Western Blot was used to detect the expression of related proteins. The gene expression profiling post combination treatment was analyzed by RNA-Seq. Finally, CDX and PDX models were used to evaluate the synergistic anti-tumor effects of the combination treatment in vivo. Results: The novel EZH2 inhibitor SHR2554 inhibited proliferation and induced G1 phase arrest in EZH2-mutant DLBCL cell lines. The combination of EZH2 inhibitor SHR2554 with histone deacetylase (HDAC) inhibitor chidamide (hereafter referred to as HBI8000) exerted synergistic anti-proliferative activity in vitro and in vivo. Gene expression profile analysis revealed dramatic inhibition of the DNA replication process in combined treatment. Conclusions: SHR2554, a potent, highly selective small molecule inhibitor of EZH2, inhibited EZH2-mutant DLBCL more significantly in vitro and in vivo. The combination of HDAC inhibitor HBI8000 with EZH2 inhibitor SHR2554 exhibited dramatic anti-tumor activity in both mutant and wild-type DLBCL, which may become a potential therapeutic modality for the treatment of DLBCL patients.

An Orally Available Small Molecule BCL6 Inhibitor Effectively Suppresses Diffuse Large B Cell Lymphoma Cells Growth in Vitro and in Vivo

2021 ◽  
Author(s):  
Yajing Xing ◽  
Weikai Guo ◽  
Min Wu ◽  
Jiuqing Xie ◽  
Dongxia Huang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cell ◽  
Small Molecule ◽  
Target Genes ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Large B Cell Lymphoma ◽  
Large B Cell

Abstract Background: The transcription factor B cell lymphoma 6 (BCL6) is an oncogenic driver of diffuse large B cell lymphoma (DLBCL) and mediates lymphomagenesis through transcriptional repression of its target genes by recruiting corepressors to its N-terminal broad-complex/tramtrack/bric-a-brac (BTB) domain. Blocking the protein-protein interactions of BCL6 and its corepressors has been proposed as an effective approach for the treatment of DLBCL. However, BCL6 inhibitors with excellent drug-like properties are rare. Hence, the development of BCL6 inhibitors is worth pursuing. Methods: We screened our internal chemical library by luciferase reporter assay and Homogenous Time Resolved Fluorescence (HTRF) assay and a small molecule compound named WK500B was identified. The binding affinity between WK500B and BCL6 was evaluated by surface plasmon resonance (SPR) assay and the binding mode of WK500B and BCL6 was predicted by molecular docking. The function evaluation and anti-cancer activity of WK500B in vitro and in vivo was detected by immunofluorescence assay, Real-Time Quantitative PCR, cell proliferation assay, cell cycle assay, cell apoptosis assay, enzyme-linked immunosorbent assay (ELISA), germinal centre (GC) formation mouse model and mouse xenograft model. Results: WK500B engaged BCL6 inside cells, blocked BCL6 repression complexes, reactivated BCL6 target genes, killed DLBCL cells and caused apoptosis as well as cell cycle arrest. In animal models, WK500B inhibited germinal centre formation and DLBCL tumor growth without toxic and side effects. Moreover, WK500B showed favourable pharmacokinetics and presented superior druggability compared to other BCL6 inhibitors. Conclusions: WK500B showed strong efficacy and favourable pharmacokinetics and presented superior druggability compared to other BCL6 inhibitors. So, WK500B is a promising candidate that could be developed as an effective orally available therapeutic agent for DLBCL.

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