Inhibition of Proteasome Is Associated with Early Alterations of Cell Cycle Regulators and Induces Synergistic Antitumour Activities in Mantle Cell Lymphoma in a Sequence Dependent Manner.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2409-2409 ◽  
Author(s):  
Alessandro Pastore ◽  
Malte Rieken ◽  
Oliver Weigert ◽  
Yvonne Zimmermann ◽  
Grit Hutter ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Single Agent ◽  
Proteasome Inhibition ◽  
Cell Cycle Regulators ◽  
Cytostatic Drugs ◽  
Cytostatic Agents ◽  
Bortezomib Treatment ◽  
Mantle Cell

Abstract Mantle cell lymphoma (MCL) displays an especially poor clinical outcome with only transient response to conventional chemotherapy, continuous relapses and a median survival of only 3 - 4 years. The Ubiquitin-proteasome pathway is known to alter homeostasis of various oncogenes, transcription factors (e.g. NF-κB) regulators of cell cycle progression and apoptosis. In various phase II trials, proteasome inhibition with single agent bortezomib (Velcade®) achieved response rates of up to 60% in relapsed disease. Five MCL cell lines (HBL2, Granta 519, Jeko-1, NCEB-1 and Rec-1) and two hematological control cell lines (Jurkat, Karpas 422) were treated with bortezomib at a previously defined effective concentration (25 nM). Real-time RT-PCR and Western Blot analysis of cyclin D1 (CCND1), Cdk inhibitors (INK4s, KIPs), and other regulators of cell cycle and apoptosis were performed at various time points during bortezomib treatment (0 to 12 hours). Additionally, analyses of cell cycle were performed by flow cytometry. All cells lines were also exposed to different doses of bortezomib in combination with various cytostatic drugs, cell proliferation (WST-1 assay) and apoptosis (Annexin V PE/7-AAD staining) were analysed. After only 2 - 4 hours of bortezomib treatment analysis of relative RNA expression levels revealed downregulation of Cdk4 inhibitor p21CIP1, CCND1 and BCL2, thus representing early effects of proteasome inhibition in MCL cell lines. In contrast, CCND1 expression temporarily increased in cell lines with moderate sensitivity to bortezomib. Interaction between bortezomib and cytostatic drugs were evaluated applying the combination index (CI). Simultaneous exposure to bortezomib and various cytostatic drugs (cytarabine, mitoxantrone, fludarabine and gemcitabine) resulted in a significantly enhanced inhibition of proliferation and apoptosis. In order to investigate the interaction of cytostatic agents and bortezomib different incubation schedules were evelusated. Notably, pre-exposure to cytarabine and subsequent proteasome inhibition results in a strong synergism (CI = 0.5) that was not observed with prior bortezomib incubation. Interesting this pattern is chemotherapy specific, since bortezomib pre-incubation induced synergism with mitoxantrone (CI = 0.6). Finally, combination of cytarabine or gemcitabine with bortezomib was able to sensitize and inhibit cell proliferation of MCL cell lines resistant to single agent treatment. In summary, alteration of protein expression profiles and cell cycle regulators occur early after proteasome inhibition in MCL cell lines. In addition, combination of bortezomib with distinct cytostatic agents demonstrated a synergistic schedule dependent efficacy in vitro. Currently, confirmatory analyses of primary patient samples are being performed representing the rationale of a future randomized phase II/III study of the European MCL Network.

scholarly journals Abemaciclib-Based Combinational Therapies to Overcome Therapeutic Resistance in Mantle Cell Lymphoma

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 33-34
Author(s):  
Yuxuan Che ◽  
Yang Liu ◽  
Lingzhi Li ◽  
Holly Hill ◽  
Joseph McIntosh ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Lines ◽  
Research Funding ◽  
Cell Lymphoma ◽  
Single Agent ◽  
Therapeutic Resistance ◽  
Cycle Arrest ◽  
Mantle Cell ◽  
Ic50 Values

Introduction The past decades witnessed dramatic improvement of overall survival rate of mantle cell lymphoma (MCL) patients by constant efforts in developing novel therapeutic strategies that include ibrutinib and venetoclax. Nevertheless, resistance is still a major challenge in refractory/relapsed MCL patients. Chromosomal translocation t(11:14)(q13:q32) of the cyclin D1 (CCND1) gene is the hallmark of MCL, which leads to overexpression of cyclin D1. This overexpression promotes aberrant cell cycle progression by activating CDK4/6. Abemaciclib is a selective CDK4/6 inhibitor used as a clinical treatment of breast cancer and has been shown to be effective in preclinical human MCL xenograft models. It has also been used in a phase II clinical trial as a single agent among refractory/relapsed MCL patients with an objective response rate of 35.7%. In this preclinical study, we aim to evaluate the benefit of a combinational therapeutic strategy using abemaciclib with other molecular targeting agents among MCL patients with therapeutic resistance. Methods Cytotoxic efficacy of abemaciclib as a single agent and in combination with other drugs on different MCL cell lines and primary lymphoma cells from MCL patients with or without resistance was used as a key criterion for screening beneficial therapeutic strategies. Cell apoptosis and cell cycle arrest assays were conducted to further evaluate those effective combinations. Western blot was performed to investigate the mechanism of action of the combinations. Finally, the efficacy of abemaciclib alone or in combination were assessed in ibrutinib-resistant or venetoclax-resistant MCL PDX models in vivo. Results Our preliminary data showed that all MCL cell lines involved in this study were highly sensitive to abemaciclib treatment with IC50 values ranging from 50 nM to 1 µM. Further investigation of abemaciclib cytotoxicity on ibrutinib and/or venetoclax resistant MCL cell lines showed effective inhibition with a higher IC50 values ranging from 5 µM to 10 µM. More importantly, abemaciclib had potent efficacy on cells from primary MCL patients as well as from patients with acquired ibrutinib resistance. Our recent findings revealed that the addition of PI3K inhibitor TGR-1202 significantly enhanced cytotoxicity of abemaciclib in both sensitive and resistant MCL cell lines. Abemaciclib significantly inhibited phosphorylation of Rb1, the active form of the protein, in 4 different MCL cell lines. The active Rb1 maintains the cell in the G1 phase, preventing progression through the cell cycle and acting as a growth suppressor. The result suggests that CDK4/6 inhibition with abemaciclib disrupts CDK4/6 suppressive activity towards pRb-E2F and induce cell cycle arrest in the MCL cells. Interestingly, abemaciclib somehow interrupted phosphorylation of Chk1, which is continuously phosphorylated and hence activated in the MCL cell lines. Inhibiting activation of Chk1 by abemaciclib may induce cell death via unmonitored and accumulated DNA damage. The efficacy of abemaciclib in combination with Bcl-2 or BTK inhibitors in MCL cell lines and isolated cells from MCL patients are ongoing. These data suggest that abemaciclib in combination with other therapeutic drugs could be beneficial in targeting therapeutic resistant MCL cells. Conclusions Abemaciclib showed impressive therapeutic potency on both MCL cell lines and isolated primary cells from MCL patients, which is likely due to the predominant contribution of cyclin D1-CDK4/6 pathway to malignancy. Other agents, such as PI3K inhibitors, can sensitize abemaciclib in therapeutic resistant MCL cells. Thus, an abemaciclib based multi-drug combinational strategy may be a promising therapy for refractory/relapsed MCL patients in the near future. Disclosures Wang: Beijing Medical Award Foundation: Honoraria; Lu Daopei Medical Group: Honoraria; Kite Pharma: Consultancy, Other: Travel, accommodation, expenses, Research Funding; Pulse Biosciences: Consultancy; Loxo Oncology: Consultancy, Research Funding; Targeted Oncology: Honoraria; OMI: Honoraria, Other: Travel, accommodation, expenses; Nobel Insights: Consultancy; Guidepoint Global: Consultancy; Dava Oncology: Honoraria; Verastem: Research Funding; Molecular Templates: Research Funding; OncLive: Honoraria; Celgene: Consultancy, Other: Travel, accommodation, expenses, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Oncternal: Consultancy, Research Funding; Juno: Consultancy, Research Funding; BioInvent: Research Funding; VelosBio: Research Funding; Acerta Pharma: Research Funding; InnoCare: Consultancy; MoreHealth: Consultancy; Pharmacyclics: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding.

Cell Cycle Dysregulation Represents an Early Effect of the Proteasome Inhibitor Bortezomib in Mantle Cell Lymphoma.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2287-2287 ◽  
Author(s):  
Grit Hutter ◽  
Yvonne Zimmermann ◽  
Malte Rieken ◽  
Marc Weinkauf ◽  
Oliver Weigert ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Expression ◽  
Cyclin D1 ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Proteasome Inhibitor ◽  
Cell Lymphoma ◽  
Genetic Alterations ◽  
Cell Cycle Regulators ◽  
Mantle Cell

Abstract Mantle cell lymphoma (MCL) is a distinct subtype of malignant lymphoma with an especially poor clinical outcome, a median survival time of 3 years and virtually no long-term survivors. On the molecular level, MCL is characterized by the chromosomal translocation t(11;14)(q13;q32) resulting in the constitutive overexpression of cyclin D1. However, additional genetic alterations of cell cycle regulators, e.g. deletions of the INK4A gene cluster, are detectable in the majority of cases. In various phase II studies the proteasome inhibitor bortezomib (Velcade) has demonstrated a high clinical efficacy with up to 60% remission rates in relapsed MCL. Additionally, in a previous in vitro study, the inhibitor induced a downregulation of cyclin D1 expression and a concomitant G(1) cell cycle arrest. However, little is known which molecules represent the critical targets of proteosome inhibition and how different regulators of cell cycle and apoptosis (inhibitors of CDK/INK4: p15INK4A, p16INK4B -and p14ARF and other kinase inhibitor proteins/KIP: 21CIP1, p27KIP1 and p57KIP2) are affected. 4 MCL cell lines (HBL2, GRANTA 519, Jeko-1, NCEB-1) and 2 hematological control cell lines (Jurkat, Karpas 422) were exposed to bortezomib at the minimal cytotoxic concentration (25 nmol) which corresponds to clinically achieved drug levels and results in a significant cytolysis after 48 – 72 hours. Real-time RT-PCR and protein expression levels of various CDK inhibitors (INK4s, KIPs) and cyclin D1 were determined a 0, 4, 8 and 12 hours after treatment with bortezomib. In addition, RNA- and protein expression data were compared to functional cell cycle phase (FACS) and cell apoptosis. Prelimenary data indicate that downregulation of cyclin D1 RNA expression after 12 and 24h of treatment represents a rather late event whereas alterations of other cell cycle regulators (like p21CIP1) were detected siginificantly earlier in all four MCL cell lines. Thus, expression of cell cycle regulators may indicate early events of proteasome inhibition. A comparative analysis of the cell cycle regulation network is currently being performed and will be presented at the conference.

Bortezomib Resistant Constitutive NF-κB Activation in Mantle Cell Lymphoma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3465-3465
Author(s):  
David T. Yang ◽  
Ken H. Young ◽  
Brad S. Kahl ◽  
Shigeki Miyamoto
Keyword(s):  
Dna Binding ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Proteasome Inhibitor ◽  
Cytotoxic Effect ◽  
Cell Lymphoma ◽  
Proteasome Inhibition ◽  
Bortezomib Treatment ◽  
Mantle Cell ◽  
Synergistic Cytotoxic Effect

Abstract Bortezomib is a proteasome inhibitor whose antineoplastic effects include inhibition of NF-κB, a transcription factor whose deregulation may play a central role in mantle cell lymphoma (MCL) pathogenesis. Bortezomib has shown clinical efficacy in relapsed and refractory cases of MCL with response rates of 40%. NF-κB can be activated through several pathways, including a proteasome inhibitor resistant pathway. It remains unknown whether MCL harbors bortezomib resistant constitutive NF-κB activity, but characterization of this may have important implications in elucidating bortezomib resistance and also in establishing rational therapeutic combinations. We investigated the effect of bortezomib on constitutive NF-κB activity in 3 EBV-negative MCL cell lines (Jeko, Rec-1 and Z138) and 20 MCL patient samples. Electrophoretic mobility supershift assay demonstrated that each of the cell lines had distinct NF-κB complexes with the Jeko and Rec-1 containing mainly p50/p65 and p50/cRel heterodimers, and Z138 comprised almost entirely of p52/RelB heterodimers. At a physiologically achievable dose of bortezomib (20nM), a live cell-based proteasome inhibition assay demonstrated greater than 80% proteasome inhibition in all three cell lines. Treatment of Jeko cells with such a dose resulted in a 50% decrease of NF-κB DNA binding, in contrast to a 10 to 30% increase of DNA binding in Rec-1 and Z138 cells by electrophoretic mobililty shift assay. Of 10 MCL patient samples from which results could be obtained, only 2 demonstrated a greater than 50% decrease in NF-κB DNA binding after treatment with 20nM and 100nM of bortezomib, whereas the remainder showed either no inhibition or even increased binding. Thus, bortezomib resistant constitutive NF-κB activity appears to be present in Rec-1, Z138, and a majority of MCL cases. Cytotoxicity assessed by flow cytometry following staining with propidium iodide showed Rec-1 and Z138 cells had greater resistance to bortezomib induced apoptosis (82 ± 5% and 69 ± 5% viability) than Jeko cells (47 ± 6% viability) after 20nM bortezomib treatment for 24 hours. Combining bortezomib with perillyl alcohol, a known suppressor of proteasome inhibitor resistant NF-κB activation, resulted in a synergistic cytotoxic effect in all 3 cell lines as assessed by the combination index (CI) method with CIs of 0.31, 0.32, and 0.60 for Jeko, Rec-1, and Z138 cells respectively, where CI of 0.1–0.3 is strong synergism, 0.3–0.7 is synergism, 0.7–0.85 is moderate synergism and 0.85–0.9 is slight synergism. In conclusion, our findings suggest that bortezomib resistant NF-κB activity is present in a significant subset of MCL cases, and the combination of bortezomib with a suppressor of proteasome inhibitor resistant NF-κB activity may elicit a synergistic cytotoxic effect in MCL.

scholarly journals BET bromodomain inhibitor birabresib in mantle cell lymphoma: in vivo activity and identification of novel combinations to overcome adaptive resistance

ESMO Open ◽  
2018 ◽  
Vol 3 (6) ◽  
pp. e000387 ◽  
Author(s):  
Chiara Tarantelli ◽  
Elena Bernasconi ◽  
Eugenio Gaudio ◽  
Luciano Cascione ◽  
Valentina Restelli ◽  
...  
Keyword(s):  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Antitumour Activity ◽  
Single Agent ◽  
Treatment Strategies ◽  
Bet Inhibitor ◽  
Mantle Cell

BackgroundThe outcome of patients affected by mantle cell lymphoma (MCL) has improved in recent years, but there is still a need for novel treatment strategies for these patients. Human cancers, including MCL, present recurrent alterations in genes that encode transcription machinery proteins and of proteins involved in regulating chromatin structure, providing the rationale to pharmacologically target epigenetic proteins. The Bromodomain and Extra Terminal domain (BET) family proteins act as transcriptional regulators of key signalling pathways including those sustaining cell viability. Birabresib (MK-8628/OTX015) has shown antitumour activity in different preclinical models and has been the first BET inhibitor to successfully undergo early clinical trials.Materials and methodsThe activity of birabresib as a single agent and in combination, as well as its mechanism of action was studied in MCL cell lines.ResultsBirabresib showed in vitro and in vivo activities, which appeared mediated via downregulation of MYC targets, cell cycle and NFKB pathway genes and were independent of direct downregulation of CCND1. Additionally, the combination of birabresib with other targeted agents (especially pomalidomide, or inhibitors of BTK, mTOR and ATR) was beneficial in MCL cell lines.ConclusionOur data provide the rationale to evaluate birabresib in patients affected by MCL.

Cell Cycle Regulation by Iron: Novel Approaches to Mantle Cell Lymphoma Therapy.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2515-2515 ◽  
Author(s):  
Heather Gilbert ◽  
John Cumming ◽  
Josef T. Prchal
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Cyclin D1 ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Iron Chelation ◽  
Lymphoma Cell ◽  
Protein Levels ◽  
Mantle Cell

Abstract Abstract 2515 Poster Board II-492 Mantle cell lymphoma is a well defined subtype of B-cell non-Hodgkin lymphoma characterized by a translocation that juxtaposes the BCL1 gene on chromosome 11q13 (which encodes cyclin D1) next to the immunoglobulin heavy chain gene promoter on chromosome 14q32. The result is constitutive overexpression of cyclin D1 (CD1) resulting in deregulation of the cell cycle and activation of cell survival mechanisms. There are no “standard” treatments for MCL. Despite response rates to many chemotherapy regimens of 50% to 70%, the disease typically progresses after treatment, with a median survival time of approximately 3-4 years. Mantle cell lymphoma represents a small portion of malignant lymphomas, but it accounts for a disproportionately large percentage of lymphoma-related mortality. Novel therapeutic approaches are needed. In 2007, Nurtjaha-Tjendraputra described how iron chelation causes post-translational degradation of cyclin D1 via von Hippel Lindau protein-independent ubiquitinization and subsequent proteasomal degradation (1). Nurtjaha-Tjendraputra demonstrated that iron chelation inhibits cell cycle progression and induces apoptosis via proteosomal degradation of cyclin D1 in various cell lines, including breast cancer, renal carcinoma, neuroepithelioma and melanoma. Our preliminary data show similar findings in mantle cell lymphoma. To establish whether iron chelation can selectively inhibit and promote apoptosis in mantle cell derived cell lines, the human MCL cell lines Jeko-1, Mino, Granta and Hb-12; the Diffuse Large B cell lymphoma line SUDHL-6; and the Burkitt's Lymphoma lines BL-41 and DG75 were grown with media only, with two different iron chelators (deferoxamine (DFO) and deferasirox) at various concentrations (10, 20, 40, 100 and 250 μM), and with DMSO as an appropriate vehicle control. Cells were harvested at 24, 48 and 72 hours. For detection of apoptotic cells, cell-surface staining was performed with FITC-labeled anti–Annexin V antibody and PI (BD Pharmingen, San Diego, CA). Cell growth was analyzed using the Promega MTS cytotoxicity assay. CD1 protein levels were assessed using standard Western blot techniques. At 24, 48 and 72 hours of incubation with iron chelators, the mantle cell lymphoma cell lines showed significantly increased rates of apoptosis compared to the non-mantle cell lymphoma cell lines (p<0.0001 for all time points). DFO and deferasirox inhibted cell growth with an IC50 of 18 and 12 μM respectively. All of the mantle cell lines had measurable cyclin D1 levels at baseline. None of the non-mantle cell lines expressed baseline measurable cyclin D1. In the mantle cell lines, cyclin D1 protein levels were no longer apparent on western blot after 24 hours of incubation with chelation. We then added ferrous ammonium sulfate (FAS) to DFO in a 1:1 molarity ratio and to deferasirox in a 2:1 ratio, and then treated the same lymphoma cell lines with the FAS/chelator mixture and with FAS alone for 72 hours. Adding iron to the chelators completely negated all the pro-apoptotic effects that were seen with iron chelation treatment. Treating with FAS alone had no effect on cell growth or apoptosis. Iron chelation therapy with both DFO and deferasirox results in decreased cell growth, increased cellular apoptosis, and decreased cyclin D1 protein levels in vitro in mantle cell lymphoma. The cytotoxic effects are prevented by coincubation with ferrous ammonium citrate, confirming that the effects are due to iron depletion. Proposed future research includes further defining the molecular basis of iron chelation effects; studying these therapies in combination with other cancer treatments both in vitro and in vivo; and studying iron chelation therapy in mantle cell lymphoma patients. 1. Nurtjahja-Tjendraputra, E., D. Fu, et al. (2007). “Iron chelation regulates cyclin D1 expression via the proteasome: a link to iron deficiency-mediated growth suppression.” Blood109(9): 4045–54. Disclosures: No relevant conflicts of interest to declare.

Enzastaurin Treatment Affects Multiple Regulatory Pathways at Transcriptome and Cellular Proteome Level of Mantle Cell Lymphoma

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2893-2893
Author(s):  
Marc Weinkauf ◽  
Grit Hutter ◽  
Yvonne Zimmermann ◽  
Malte Rieken ◽  
Alessandro Pastore ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mantle Cell Lymphoma ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Signal Pathways ◽  
Rna Expression ◽  
Cellular Functions ◽  
Mantle Cell ◽  
Canonical Pathways

Abstract Abstract 2893 Background: The protein kinase C beta inhibitor enzastaurin is one of the promising molecular targeted approaches currently investigated in mantle cell lymphoma (MCL), a disease still characterized by a dismal long term prognosis. Methods: Four well characterized MCL cell lines (Granta 519, HBL-2, Jeko-1 and Rec-1) as well as three patient samples were exposed to enzastaurin at a previously defined dose (10 μM). Cell viability as well as cell cycle activity were analyzed by tryphan blue exclusion test and flow cytometry, respectively, after 24 and 48 hours. To dissect the regulatory processes targeted by enzastaurin, the panel of MCL cell lines was screened on both protein and RNA expression levels (2D-gel electrophoresis and mass spectrometric peptide fingerprint analysis and Affymetrix microarray) after 4h enzastaurin treatment. Results: Enzastaurin in vitro resulted in a reduced viability and cell proliferation by 15–20% after 24h in cell lines and 9–20% in primary patient samples after 48h. This effect was related to a G2/M block of cell cycle and induction of apoptosis. Based on the proteome and transcriptome analysis of early alterations, only HSPD1 was affected on both regulation levels. Nonetheless, combined analysis of alterations on both, protein and RNA expression levels, resulted in identification of common signal pathways characterizing a more comprehensive network of affected molecular interactions mapping to distinct canonical pathways and defined cellular functions. Indicated canonical pathways included ‘calcium signalling', (CAMKK2, HDAC5, HDAC9, TP63) ‘calcium induced T-lymphocyte apoptosis' (MEF2D, NR4A1, PRKCG, TRA@), ‘NFkB signalling' (KRAS, MAP3K8, TNFAIP3, TNFRS17) and ‘molecular mechanisms of cancer' (APAF1, CDKN2D, FOS, PAK6), whereas the top ranking cellular functions were ‘cellular growth and proliferation' (CCNG2, EIF4E, PDIA3, TOP1, TPM1,), ‘cell death' (BCL6, EEF1D, PAK6, RAD50), ‘cell cycle'(AKAP9, BMF, CUL5, GADD45B, PDIA3), ‘cellular development' (APAF1, GAS7, ID1, PAX8) and ‘gene expression' (ABCG1, HOXB4, LMO4, PIM1). Alterations of these pathways were confirmed by Western Blot analysis of selected candidate proteins marker proteins of the regulated pathways. Conclusion: In summary, the combined approach of RNA and protein analysis revealed the targeted signal pathways after Enzastaurin exposure. These data will allow a more rationally designed combination of biologicals to finally improve the clinical outcome of MCL. Disclosures: Dreyling: Eli Lilly: Support of in vitro studies of Enzostaurin in MCL.

The Bioactive Polyphenol Curcumin (diferuloylmethane) In Human Apolipoprotein A-1 Nanodisks Enhances Apoptosis and G1 Cell Cycle Arrest In Mantle Cell Lymphoma Compared with Free Curcumin

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3934-3934
Author(s):  
Amareshwar T.K. Singh ◽  
Mistuni Ghosh ◽  
C. Shad Thaxton ◽  
Trudy M. Forte ◽  
Robert O. Ryan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Drug Delivery ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Parp Cleavage ◽  
Cycle Arrest ◽  
Mantle Cell ◽  
Induced Apoptosis

Abstract Abstract 3934 Background: Mantle cell lymphoma (MCL) is a pre–germinal center neoplasm characterized by cyclin D1 overexpression resulting from translocation of the cyclin D1 gene on 11q13 to the promoter of the immunoglobulin heavy chain locus on 14q32. Since MCL is incurable with standard lymphoma therapies, new treatment approaches are needed that target specific biologic pathways. The bioactive polyphenol curcumin (Curc), derived from the rhizome of Curcuma longa Linn, has been shown to have pleiotropic activities related to its complex chemistry and its influence on multiple signaling pathways including NF-kB, Akt, Nrf2 and pathways involved in metastasis and angiogenesis. Curc has been shown to cause growth arrest and apoptosis of BKS-2 immature B-cell lymphoma by downregulating growth and survival promoting genes (Clin Immunol 1999; 93:152). However, because of poor aqueous solubility Curc has had limited clinical utility, so investigators have explored nanoparticle drug delivery approaches (J Nanobiotech 2007, 5:3, MCT 2010; 9:2255). We reasoned that effective and targeted drug delivery by nanoparticles required appropriate receptors to facilitate binding. We therefore screened lymphoma cell lines for receptors that recognize apolipoprotein (apo) A-1. We hypothesized that a novel discoidal nanoparticle (ND) consisting of apoA-1, phospholipid and Curc (Curc ND) would bind to such receptors to facilitate drug delivery. Methods: We compared biologic activity of free Curc vs. Curc-ND in MCL cell lines expressing receptors for apoA-1. Cell lines were grown and maintained in culture, treated, and apoptosis and cell cycle progression was measured by flow cytometry. Relevant signaling intermediates and presence of apoA-1 receptors were measured by immunoblotting using specific antibodies. Results: Granta and Jeko cells (both MCL cell lines) expressed apoA-1 receptors including class B scavenger receptor (SR-B1) and the ATP-binding cassette transporter of the sub-family G1 (ABCG1). To compare the pro-apoptotic effect of free Curc and Curc-ND, Granta cells were incubated with free Curc, Curc-ND, empty ND, and medium alone (untreated). Compared to medium alone, empty ND had no effect while free Curc (20 μM) induced apoptosis. Curc-ND produced a dose-dependent increase in apoptosis, with ∼70% apoptosis at 20 μM. To investigate the mechanism of Curc-ND induced apoptosis, apoptosis-related proteins were studied in cultured Granta cells. A time-dependent decrease in caspase-9 levels was observed following incubation with Curc-ND or free Curc. The decrease in caspase-9 seen with Curc-ND, however, occurs much earlier (between 2–4 h of incubation) than for free-Curc. Caspase-3 was undetectable after 16 h with either treatment. Loss of this band implies activation of caspase-3, which was confirmed by PARP cleavage, wherein a decrease in the 116 kD band was accompanied by an increase in the 85 kD cleavage product. Unlike free Curc, Curc-ND induced PARP cleavage even at 16 h of incubation, suggesting sustained drug release. Curc-ND downregulated cyclin D1, decreased Akt phosphorylation and enhanced cleavage of caspases-9 and -3, and PARP. In addition, Curc-ND induced G1 cell cycle arrest to a greater extent than free Curc in Granta and Jeko cells (Granta: Control 34% G1, Curc 37% G1, Curc-ND 46% G1; Jeko: Control 39% G1, Curc 49% G1, Curc-ND 54% G1). Conclusion: We have shown that the MCL cell lines Granta and Jeko express apoA-1 receptors, making them likely targets for discoidal nanoscale delivery vehicles stabilized with Apo-A1. These nanodisks, when carrying the polyphenol Curc, can result in increased caspase -dependent apoptosis, cell cycle arrest, downregulation of cyclin-D1 and decreased p-Akt. These data suggest that the pleiotropic polyphenol Curc has cell killing/arrest activity in MCL and that Curc-ND may be a potential therapeutic with drug targeting ability. Disclosures: Forte: Lypro Biosciences: Employment.

The HDACi Romidepsin Markedly Synergizes With Inhibition Of ATM By KU60019 In Mantle Cell Lymphoma

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3066-3066 ◽  
Author(s):  
Luigi Scotto ◽  
Kelly Zullo ◽  
Xavier Jirau Serrano ◽  
Laura K Fogli ◽  
Owen A. O'Connor
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Mantle Cell Lymphoma ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Cdk Inhibitor ◽  
Protein Levels ◽  
Cycle Arrest ◽  
Mantle Cell

Abstract Mantle cell lymphoma (MCL) is a disease characterized by gross cell cycle dysregulation driven by the constitutive overexpression of cyclin D1. The identification of a “proliferation signature” in MCL, underscores the necessity of new therapeutic approaches aimed at lowering the proliferative signature of the disease, theoretically shifting the prognostic features of the disease. Romidepsin, an HDAC inhibitor (HDACi) approved for the treatment of relapsed T-cell lymphoma, is thought to induce cell cycle arrest and apoptosis. Central to the block of cell proliferation is the up-regulation of the cdk inhibitor p21Cip1/Waf1. However up-regulation of p21Cip1/Waf1 has also been shown to reduce sensitivity to romidepsin. HDACi activates p21Cip1/Waf1 expression via ATM and KU60019, a specific ATM inhibitor, has been shown to decrease the p21Cip1/Waf1 protein levels in a concentration dependent manner. We sought to explore the effect of the combination of romidepsin and KU60019 in inducing cell death in MCL. Analysis of romidepsin treated Jeko-1 cell extracts showed a marked effect on the expression of proteins involved in cell cycle regulation. Decrease expression of Emi1, a mitotic regulator required for the accumulation of the APC/C substrates was observed. Emi1 is also responsible for the stability of the E3 ubiquitin ligase Skp2 that specifically recognizes and promotes the degradation of phosphorylated cdk inhibitor p27. However, decrease in Emi1 protein levels, upon addition of romidepsin, was not followed by an increased expression of the cdk inhibitor p27. On the other end, increased expression of the cdk inhibitor p21Cip1/Waf1, was a common feature of all romidepsin treated MCL lines analyzed. Cell cycle analysis via Fluorescent Activated Cell Sorting (FACS) of romidepsin treated Jeko-1 cells showed an accumulation of romidepsin treated cells in the G2/M phase when compared to the control suggesting a p21Cip1/Waf1 induced cell cycle arrest. For all cytotoxicity assays, luminescent cell viability was performed using CellTiter-GloTM followed by acquisition on a Biotek Synergy HT and IC50s calculated using the Calcusyn software. Drug: drug interactions were analyzed using the calculation of the relative risk ratios (RRR). Synergy analyses were performed using Jeko-1, Maver-1 and Z-138 cells treated with different concentrations of romidepsin corresponding to IC10-20 in combination with KU60019 at a concentration of 2.5, 5.0, 7.5 and 15 umol/L for 24, 48 and 72 hours. A synergistic cytotoxic effect was observed in all MCL cell lines when the HDACi was combined with KU60019 throughout the range of all concentrations. The RRR analysis showed a strong synergism at 48 and 72 hours in virtually all combinations of HDACi and KU60019 in all three cell lines. The results of drug:drug combination in two of the three cell lines are shown below. Protein expression analysis of Jeko-1 and Maver-1cells treated with single agents or combinations for 48 hours revealed changes in a host of proteins known to be involved in cell cycle control and apoptosis. The increased p21 protein expression upon addition of romidepsin, was not observed when the romidepsin treatment was combined with the KU60019. Increased activation of the programmed cell death proteins Caspase 8, induced by Fas, and Caspase 3 was observed upon combinations of the single agents in all three cell lines, resulting in an increased cleavage of Poly (ADP-ribose) polymerase (PARP-1). Finally, the abundance of the anti-apoptotic proteins Bcl-XL and BCL-2 showed a significant decrease after treatment with romidepsin plus increase concentrations of KU60019 when compared with their abundance in the presence of the single agents. Cell cycle analysis of Jeko-1 cells treated for 24 hours with single agents and combination suggests that the increased apoptosis is the result of inhibition of the p21Cip1/Waf1 induced G2/M cell cycle arrest by KU60019. Overall, these data demonstrated that the combination of romidepsin and KU60019 was synergistically effective in inhibiting the in vitro growth of the mantle cell lymphoma lines. Jeko-1 Maver-1 Disclosures: O'Connor: Celgene: Consultancy, Research Funding.

Cyclin D1 Maintains Mantle Cell Lymphoma Through CDK4-Independent Regulation Of DNA Replicative Checkpoints

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2512-2512
Author(s):  
Suchismita Mohanty ◽  
Atish Mohanty ◽  
Natalie Sandoval ◽  
Victoria Bedell ◽  
Joyce Murata-Collins ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Survival ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
Replication Stress ◽  
G1 Phase ◽  
Origin Firing ◽  
Mantle Cell ◽  
Cdk4 Activity

Abstract Mantle cell lymphoma (MCL) is rarely curable and therapy resistance often leaves few viable treatment options for patients. Previous studies have identified the importance of cyclin D1 (CCND1) translocation and overexpression in MCL pathogenesis, which leads to increased cyclin-dependent kinase 4 (CDK4) activity and accelerated cell cycle progression. However, targeting this abnormal cell cycle control, mainly through CDK4 inhibition causes only G1-phase growth arrest without significant cell death (Marzec et al. 2006). In contrast, prolonged inhibition of CCND1 with RNA interference induces apoptosis in MCL cell lines (Weinstein et al. 2012), suggesting an essential function of CCND1 independent of CDK4 activity. The mechanism of this non-catalytic role of CCND1 in maintaining MCL cell survival is largely unknown. To clarify the cell cycle role of CCND1 in addition to its CDK4-dependent function, we compared the effects of CCND1 and CDK4 silencing on MCL cell survival. MCL cell lines co-expressing GFP and doxycycline-inducible shRNA targeting CCND1 or CDK4 were generated. Cells with similar GFP expression levels were FACS sorted to normalize for shRNA expression. Both CCND1 and CDK4 silencing resulted in G1-phase arrest, but only CCND1-silenced cells demonstrated a marked increase in apoptosis. Investigation of the potential cause of apoptosis revealed significant accumulation of DNA double-strand breaks following CCND1 ablation, as measured by nuclear gamma-H2AX focus formation. Interestingly, CCND1-silenced cells exhibited a significant increase in 53BP1+ nuclear bodies in G1-phase, reminiscent of 53BP1 foci observed by Lukas and colleagues in cells undergoing aphidicolin-induced replication stress (Lukas et al. 2011). Analysis of replication fork movement in CCND1-depleted cells showed substantially reduced fork speed and increased frequency of origin firing, both of which are indicative of replication stress. In contrast, knockdown of CDK4 did not result in slower forks or increase in the frequency of origin firing. Genomic instability associated with replication stress was also apparent in CCND1-silenced cells, including increased micronucleus formation and recurrent chromatid gaps or breaks detected by cytokinesis-block assay and karyotyping, respectively. Analysis of DNA replicative and damage checkpoints revealed that both ATR-CHEK1 and ATM-CHEK2 pathways were activated by phosphorylation following CCND1 silencing in MCL cell lines, a xenograft animal model, and primary tumor samples, but not in non-MCL tumors. Interestingly, this activation (with the exception of ATM phosphorylation) was unsustainable over time and did not cause down-regulation of the downstream targets CDC25 and CDK1/2 but, instead, we observed an increase in CDC25A/B protein levels and CDK1/2 activity, indicating defective cell cycle checkpoints. Exposing CCND1-silenced cells to replication stress-inducing or DNA-damaging agents such hydroxyurea, aphidicolin, etoposide or ionizing radiation further amplified the checkpoint defects seen in unperturbed cells. We did not observe any significant difference in this checkpoint signaling in control and CDK4 knockdown cells under these conditions. Furthermore, CCND1-deficient cells were more sensitive to pharmacological inhibition of ATR and CHEK1 but not ATM, confirming a constitutive role of CCND1 in the ATR-CHEK1 pathway. In conclusion, these studies revealed an unexpected CDK4-independent role of CCND1 in maintaining DNA replicative checkpoints to prevent replication stress and genome instability in MCL cells. As most cancer treatments rely on agents that create DNA replication stress, targeting this function of CCND1 could provide a rational approach to overcome resistance to conventional therapies in MCL. Disclosures: No relevant conflicts of interest to declare.

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